CN104834034A - Anti-dazzle film - Google Patents

Abstract

An object of the present invention is to provide an anti-glare film which has excellent anti-glare properties over a wide viewing angle despite low haze, and which can sufficiently suppress occurrence of whitening and glare when disposed on an image display device. The antiglare film of the present invention comprises a transparent support body and an antiglare layer formed on the support body with fine surface irregularities, wherein the antiglare film has a total haze of 0.1% or more and 3% or less, and the surface The haze is not less than 0.1% and not more than 2%, the kurtosis Rku of the roughness curve of the surface irregularity is not more than 4.9, and the power spectrum of the complex amplitude calculated from the elevation of the surface irregularity and the refractive index of the antiglare layer is within a specific 2 The intensity ratios at each spatial frequency are within a given range.

Description

Anti-glare film

technical field

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

Background technique

For image display devices such as liquid crystal displays, plasma display panels, Braun tube (cathode ray tube: CRT) displays, and organic electroluminescent (EL) displays, in order to avoid Deterioration of visibility (visibility), an anti-glare film is disposed on the display surface.

As an anti-glare film, a transparent film having a surface unevenness has been mainly considered. Such an anti-glare film exhibits anti-glare properties by reducing the reflection of external light by scattering and reflecting external light (external light scattered light) by using the uneven shape of the surface. However, when the scattered light from external light is strong, the entire display surface of the image display device may be whitish and the displayed color may not be clear, so-called "whitening (白ちゃけ)" may occur. In addition, the pixel of the image display device interferes with the surface irregularities of the anti-glare film to cause luminance distribution, which may cause so-called "glare" that is difficult to see. Based on the above background, anti-glare films are required to sufficiently prevent the occurrence of "whitening" and "glare" while ensuring excellent anti-glare properties.

As such an anti-glare film, for example, in Patent Document 1, the following anti-glare film is disclosed as an anti-glare film that does not cause glare even when it is arranged on a high-definition image display device, and can sufficiently prevent the occurrence of whitening. Film: It has fine surface irregularities formed on a transparent substrate, and the average length PSm of any profile curve of the surface irregularities is 12 μm or less, and the ratio of the arithmetic mean height Pa of the profile curve to the average length PSm is Pa/PSm 0.005 or more and 0.012 or less, the proportion of surfaces with an inclination angle of 2° or less is 50% or less, and the proportion of surfaces with an inclination angle of 6° or less is 90% or more.

The anti-glare film disclosed in Patent Document 1 can effectively suppress the glare by eliminating the surface irregularities with a period of about 50 μm that tend to cause glare by making the average length PSm of any profile curve very small. However, for the anti-glare film disclosed in Patent Document 1, if the haze is to be further reduced (if low haze is to be achieved), the image display device equipped with the anti-glare film may be viewed obliquely. The anti-glare property of the surface is reduced. Therefore, the antiglare film disclosed in Patent Document 1 still has room for improvement in terms of antiglare properties at wide viewing angles.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2007-187952

Contents of the invention

The problem to be solved by the invention

An object of the present invention is to provide an anti-glare film which has excellent anti-glare properties over a wide viewing angle despite low haze, and which can sufficiently suppress occurrence of whitening and glare when disposed on an image display device.

way of solving the problem

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides an antiglare film comprising a transparent support and an antiglare layer formed on the support with fine surface irregularities,

The antiglare film has a total haze of 0.1% to 3% and a surface haze of 0.1% to 2%,

The kurtosis Rku of the roughness curve of the surface uneven shape is 4.9 or less,

The power spectrum of the complex amplitude obtained by the following power spectrum calculation method satisfies all the conditions of the following (1) to (3):

(1) The ratio H(0.01)/H(0.002) of the intensity H(0.002) of the power spectrum at a spatial frequency of 0.002 μm ^-1 to the intensity H(0.01) of the power spectrum at a spatial frequency of 0.01 μm ^-1 is 0.02 or more And below 0.6;

(2) The ratio H(0.02)/H(0.002) of the intensity H(0.002) of the power spectrum at a spatial frequency of 0.002 μm ^-1 to the intensity H(0.02) of the power spectrum at a spatial frequency of 0.02 μm ^-1 is 0.005 or more And below 0.05;

(3) The ratio H(0.04)/H(0.002) of the intensity H(0.002) of the power spectrum at a spatial frequency of 0.002 μm ^-1 to the intensity H(0.04) of the power spectrum at a spatial frequency of 0.04 μm ^-1 is 0.0005 or more And below 0.01.

<Power Spectrum Calculation Method>

(A) determine as the average surface of the imaginary plane by the average elevation of above-mentioned surface concave-convex shape;

(B) Determination of the lowest elevation plane including the lowest elevation point of the above-mentioned surface unevenness and parallel to the above-mentioned average plane as an imaginary plane, and determining the highest elevation point including the above-mentioned surface unevenness and parallel to the above-mentioned average plane as an imaginary plane the highest elevation of the plane;

(C) For a plane wave with a wavelength of 550nm incident from the main normal direction perpendicular to the above-mentioned lowest elevation surface and emitted from the above-mentioned highest elevation surface, calculate the complex of the above-mentioned highest elevation surface by the elevation of the above-mentioned surface concave-convex shape and the refractive index of the anti-glare layer Amplitude, find the power spectrum of the complex amplitude at this time.

Furthermore, for the antiglare film of the present invention, preferably

The sum Tc of transmission clarity measured by using five kinds of optical combs whose widths of dark and bright parts are respectively 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm is above 375%.

The sum Rc(45) of the reflection clarity measured at an incident angle of light of 45° using four kinds of optical combs whose widths of the dark part and bright part are 0.25mm, 0.5mm, 1.0mm and 2.0mm respectively is 180% or less,

The sum Rc(60) of the reflection clarity measured at an incident angle of light of 60° using four kinds of optical combs with dark and light widths of 0.25mm, 0.5mm, 1.0mm and 2.0mm respectively was 240% or less.

Invention effect

According to the present invention, it is possible to provide an anti-glare film which has sufficient anti-glare properties over a wide viewing angle despite low haze, and which can sufficiently suppress occurrence of whitening and glare when it is arranged in an image display device.

Description of drawings

[ Fig. 1 ] A diagram for simply explaining the elevation of the surface irregularities of the anti-glare film.

[ Fig. 2 ] A diagram for simply explaining the relationship between the height of the surface unevenness of the anti-glare film and the coordinates (x, y).

[ Fig. 3 ] A diagram for simply explaining the relationship between the level h(x, y) of the surface unevenness of the antiglare film, the level reference plane, and the highest level plane.

[ Fig. 4 ] A schematic diagram showing a state in which the elevation of the surface unevenness shape of the anti-glare film is discretely obtained.

[ Fig. 5 ] A schematic diagram showing a state in which a one-dimensional power spectrum is calculated from a two-dimensional power spectrum of complex amplitude calculated from the elevation of the surface concave-convex shape obtained as a discrete function.

[ Fig. 6 ] A graph showing a one-dimensional power spectrum H(f) of complex amplitude calculated from the elevation of the surface uneven shape of the anti-glare film with respect to the spatial frequency f.

[ Fig. 7 ] A diagram schematically showing a preferred example of a method of manufacturing a mold (first half).

[ Fig. 8 ] A diagram schematically showing a preferred example of a method of manufacturing a mold (second half).

[ Fig. 9 ] A diagram schematically showing a preferred example of a manufacturing apparatus used in the method of manufacturing an anti-glare film of the present invention.

[ Fig. 10 ] A diagram schematically showing a preferred pre-curing step in the method for producing the anti-glare film of the present invention.

[ Fig. 11 ] A diagram schematically showing a unit cell used for dazzle evaluation.

[ Fig. 12 ] A diagram schematically showing a glare evaluation device.

[ Fig. 13 ] A diagram showing a part of pattern A used in Example 1.

[ Fig. 14 ] A diagram showing a part of pattern B used in Example 2.

[ Fig. 15 ] A diagram showing a part of pattern C used in Example 3.

[ FIG. 16 ] A diagram showing a part of pattern D used in Comparative Example 1. [ FIG.

[ FIG. 17 ] A diagram showing a part of pattern E used in Comparative Example 2. [ FIG.

Symbol Description

40 base material for mold,

41 The surface (plating layer) of the base material for the mold after the first plating process and the grinding process,

46 The first surface uneven shape formed by the first etching process,

47 The surface roughness shape passivated by the second etching process,

50 photosensitive resin film,

60 masks,

70 After chrome-plating, the concave-convex shape of the surface has a passivated surface,

71 chrome plating,

80 export rollers,

81 transparent support body,

83 application area,

86 active energy ray irradiation device,

87 cylindrical molds,

88,89 pinch roller,

90 film winding device

103 lowest elevation surface,

104 Highest elevation surface.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as needed, but the dimensions and the like shown in the drawings are arbitrarily set for the convenience of observation.

The antiglare film of the present invention is characterized in that the kurtosis Rku of the roughness curve of the uneven surface shape is 4.9 or less, and the intensity of the power spectrum obtained by the above ^- mentioned power spectrum calculation method at a spatial frequency of 0.002 μm The ratios of intensities at frequencies of 0.01 μm ^-1 , 0.02 μm ^-1 and 0.04 μm ^-1 were within the above ranges, respectively.

First, a method of obtaining the kurtosis Rku of the roughness curve and the power spectrum of the complex amplitude for the antiglare film of the present invention will be described.

[Kurtosis Rku of roughness curve]

Regarding the surface irregularity shape of the antiglare layer of the antiglare film of the present invention, the kurtosis Rku of the roughness curve obtained by the method based on the JIS B 0601 standard is 4.9 or less. This large kurtosis Rku means that there are many sharp asperity portions in the surface asperity shape, that is, the surface asperity shape has many regions with sharp inclination angles. If an image display device is obtained using an anti-glare film having a large kurtosis Rku, whitening will occur in such an image display device. The inventors of the present invention found that an antiglare film having a kurtosis Rku of a roughness curve of 4.9 or less is effective in effectively suppressing whitening when the antiglare film is placed on an image display device. In order to obtain an image display device in which whitening is further suppressed, the kurtosis Rku of the roughness curve of the anti-glare film is preferably 4.5 or less, more preferably 4 or less.

The measurement conditions (sampling length, evaluation length) when measuring the kurtosis Rku of the roughness curve can be appropriately set according to the surface roughness Ra obtained by JIS B0633. That is, when the surface roughness Ra exceeds 0.006 μm and is 0.02 μm or less, the sampling length is 0.08 mm and the evaluation length is 0.4 mm, and when the surface roughness Ra exceeds 0.02 μm and is 0.1 μm or less, the sampling length 0.25mm, the evaluation length is 1.25mm, when the surface roughness Ra exceeds 0.1μm and is 2μm or less, the sampling length is 0.8mm, the evaluation length is 4mm, and the surface roughness Ra exceeds 2μm and 10μm or less In this case, the sampling length is 2.5 mm, and the evaluation length is 12.5 mm.

The above-mentioned surface roughness Ra can be measured and obtained by a method based on JIS B0601.

[Power Spectrum of Complex Amplitude]

The power spectrum of the complex amplitude calculated from the elevation of the surface unevenness of the anti-glare film and the refractive index of the anti-glare layer will be described. FIG. 1 is a cross-sectional view schematically showing the surface of the antiglare film of the present invention. As shown in Figure 1, the anti-glare film 1 of the present invention has a transparent support 101 and an anti-glare layer 102 formed on the transparent support 101. Bump 2 The surface bump shape.

Here, the "elevation of surface unevenness" in the present invention means that any point P on the surface unevenness and the above-mentioned minimum elevation surface are in the main normal direction 5 of the anti-glare film of the present invention (for the above-mentioned minimum elevation surface The straight-line distance in the normal direction). The elevation of an arbitrary point on the hypothetically determined lowest elevation surface is 0 μm, which is a reference for calculating the elevation of an arbitrary point on the surface unevenness, and is represented by the lowest elevation surface 103 in FIG. 1 .

Actually, as schematically shown in FIG. 2 , the anti-glare film includes an anti-glare layer having fine surface irregularities on a two-dimensional plane. Therefore, as shown in FIG. 2, when (x, y) is used to represent the orthogonal coordinates in the film surface, the elevation of the surface uneven shape can be expressed as a binary function h(x, y) of coordinates (x, y).

The elevation of the surface irregularities can be obtained from the three-dimensional information of the surface shape measured with a confocal microscope, an interference microscope, an atomic force microscope (AFM), or the like. The horizontal resolution required for the measuring machine is preferably 5 μm or less, more preferably 2 μm or less. In addition, the vertical resolution required for the measuring machine is preferably 0.1 μm or less, more preferably 0.01 μm or less. Examples of non-contact three-dimensional surface shape-roughness measuring instruments suitable for this measurement include New View 5000 series (manufactured by Zygo Corporation), three-dimensional microscope PLμ2300 (manufactured by Sensofar Corporation), and the like. The measurement area is preferably at least 500 μm×500 μm, more preferably 750 μm×750 μm or more, since the resolution of the power spectrum of the elevation needs to be 0.002 μm ⁻¹ or less.

FIG. 3 schematically shows the relationship between the elevation h(x, y) of the concave-convex shape of the surface and the lowest elevation surface 103 and the highest elevation surface 104 . Here, let the elevation of the highest elevation surface 104 be h _max (μm). In addition, this FIG. 3 has shown the cross-sectional structure including the highest point and the lowest point of this anti-glare film.

The optical path length d(x, y) between the lowest elevation surface 103 and the highest elevation surface 104 at the coordinates (x, y) can be expressed by the binary function h(x, y) related to the elevation, expressed by formula (1) .

[mathematical formula 1]

d(x,y)=n _AG h(x,y)+n _air [h _max -h(x,y)]…Formula (1)

Here, n _AG is the refractive index of the antiglare layer, and n _air is the refractive index of air. However, when the refractive index n _air of air is approximated to 1, the formula (1) can be expressed as the formula (2).

[mathematical formula 2]

d(x,y)=(n _AG -1)h(x,y)+h _max ...Formula (2)

Next, a plane wave of a single wavelength λ propagating in the principal normal direction 5 (the principal normal direction perpendicular to the lowest elevation surface) is incident from the transparent support body side (the lowest elevation surface 103 side) and passes through the antiglare layer side ( The complex amplitude of the plane wave in the case of emission from the highest elevation surface 104 side) will be described. The complex amplitude refers to a portion that does not include a time element when expressing the amplitude of fluctuations by a complex factor. Generally, the amplitude of a plane wave with a single wavelength λ can be represented by a complex factor using the following equation (3).

[mathematical formula 3]

$\mathrm{A\; exp}(\frac{2\mathrm{\&pi;iz}}{\mathrm{\&lambda;}}-\mathrm{\&omega;t}+{\mathrm{\&phi;}}_0)=\mathrm{A\; exp}(\frac{2\mathrm{\&pi;iz}}{\mathrm{\&lambda;}}+{\mathrm{\&phi;}}_0)\exp (-\mathrm{\&omega;t})$ ...Formula (3)

Here, A in formula (3) is the maximum amplitude of the plane wave, π is the circumference ratio, i is the imaginary number unit, z is the coordinate (optical path length relative to the origin) in the z-axis direction (principal normal direction 5), and ω is the angle frequency, t is time, for the initial phase.

The time-independent term in equation (3) is the complex amplitude. Therefore, the complex amplitude ψ(x, y) at the coordinates (x, y) of the highest elevation surface 104 shown in equation (3) for plane waves, in the time-independent term of equation (3), It can be represented by the following formula (4) obtained by substituting the said optical path length d(x, y) into z.

[mathematical formula 4]

$\mathrm{\&psi;}(x,\mathrm{the\; y})=\mathrm{A\; exp}[\frac{2\mathrm{\&pi;i}}{\mathrm{\&lambda;}}d(x,\mathrm{the\; y})+{\mathrm{\&phi;}}_0]=\mathrm{A\; exp}\left({\mathrm{\&phi;}}_0\right)\exp \left[\frac{2\mathrm{\&pi;i}}{\mathrm{\&lambda;}}d(x,\mathrm{the\; y})\right]$ ...Formula (4)

Further, in formula (4), the maximum amplitude A of the plane wave and the initial phase It does not depend on the coordinates (x, y), and in the present invention to specify the distribution of the surface unevenness at the coordinates (x, y), it is a constant, so A=1 and φ ₀ =0 are assumed hereinafter. In addition, when substituting the above-mentioned formula (2), the complex amplitude ψ(x, y) can be represented by the following formula (5). It should be noted that, in the present invention, λ=550nm is used as a benchmark.

[mathematical formula 5]

$\mathrm{\&psi;}(x,\mathrm{the\; y})=\exp \left[\frac{2\mathrm{\&pi;i}}{\mathrm{\&lambda;}}\right\{({\mathrm{no}}_{\mathrm{AG}}-1)h(x,\mathrm{the\; y})+h_{\max }\left\}\right]$ ...Formula (5)

Next, a method for obtaining a power spectrum of a complex amplitude will be described. First, the binary function ψ(x, y) represented by the formula (5) and the binary function Ψ(f _x , f _y ) are solved by the two-dimensional Fourier transform defined by the formula (6).

[mathematical formula 6]

$\mathrm{\&Psi;}(f_x,f_{\mathrm{the\; y}})=\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\mathrm{\&psi;}(x,\mathrm{the\; y})\exp \left[2\mathrm{\&pi;i}(f_{x}x+f_{\mathrm{the\; y}}\mathrm{the\; y})\right]\mathrm{dxdy}$ ...Formula (6)

Here, f _x and f _y are frequencies in the x-direction and y-direction, respectively, and have dimensions of the reciprocal of the length. By taking the absolute value of the obtained binary function Ψ(f _x ,f _y ) to the second power, the two-dimensional power spectrum H(f _x ,f _y ) can be obtained according to formula (7).

[mathematical formula 7]

H(f _x ,f _y )＝|Ψ(f _x ,f _y )| ² …Formula (7)

This two-dimensional power spectrum H(f _x , f _y ) represents the spatial frequency distribution of the complex amplitude calculated from the height of the surface unevenness of the antiglare film. Since the anti-glare film is isotropic, the binary function H(f _x , f _y ) representing the two-dimensional power spectrum of the complex amplitude can be obtained by a one-variable function that only depends on the distance f from the origin (0,0) H(f) said. Next, a method for solving the unary function H(f) from the binary function H(f _x , f _y ) will be shown. First, a binary function H(f _x , f _y ) that is a two-dimensional power spectrum of complex amplitude is expressed using polar coordinates based on Equation (8).

[mathematical formula 8]

H(f _x ,f _y )＝H(f cosθ,f sinθ)...Formula (8)

Here, θ is the declination angle in Fourier space. The one-variable function H(f) can be obtained by calculating the rotation average of the two-variable function H(fcosθ, fsinθ) expressed in polar coordinates based on Equation (9). Hereinafter, the unary function H(f) obtained from the rotation average of the binary function H(f _x , f _y ) which is a two-dimensional power spectrum of complex amplitude is also referred to as one-dimensional power spectrum H(f).

[mathematical formula 9]

$h\left(f\right)\&equiv;\frac{1}{2\mathrm{\&pi;}}\underset{0}{\overset{2\mathrm{\&pi;}}{\&Integral;}}h(f\cos \mathrm{\&theta;},f\sin \mathrm{\&theta;})\mathrm{d\&theta;}$ ...Formula (9)

The antiglare film of the present invention is characterized in that the intensity H(0.002) of the one-dimensional power spectrum H(f) of the complex amplitude calculated from the elevation of the surface concave ^- convex shape at a spatial frequency of 0.002 ^μm The ratio H(0.01)/H(0.002) of the intensity H(0.01), the ratio H(0.02)/H(0.002) of the intensity H(0.002) to the intensity H(0.02) at the spatial frequency 0.02μm ^-1 , And the ratio H(0.04)/H(0.002) of the intensity H(0.002) to the intensity H(0.04) at the spatial frequency of 0.04 μm ⁻¹ is within a specific range.

Hereinafter, the method of calculating the two-dimensional power spectrum of the complex amplitude calculated from the elevation of the surface unevenness shape which an anti-glare film has is demonstrated more concretely. The above-mentioned three-dimensional information on the surface shape actually measured by a confocal microscope, interference microscope, atomic force microscope, etc. is usually obtained in the form of discrete values, that is, a plurality of elevations corresponding to the measurement points. FIG. 4 is a schematic diagram showing a state in which a function h(x, y) representing an elevation is obtained discretely. As shown in Figure 4, the orthogonal coordinates in the film plane are represented by (x, y), and the film projection surface 3 is represented by a dotted line on the line divided by Δx in the x-axis direction and every Δy in the y-axis direction In the case of dividing lines, in actual measurement, the elevation of the surface unevenness is obtained as discrete elevation values for each area Δx×Δy divided by each dotted line on the film projection surface 3 .

The number of obtained elevation values is determined by the measurement range, and Δx and Δy. As shown in Figure 4, when the measurement range in the x-axis direction is set as X=MΔx and the measurement range in the y-axis direction is Y=NΔy, the obtained elevation The number of values is M×N.

As shown in FIG. 4 , when the coordinates of the focus point A on the film projection plane 3 are (mΔx, nΔy) [where m is 0 to M-1 and n is 0 to N-1], The elevation of point P on the membrane surface corresponding to point A can be represented by h(mΔx, nΔy).

Here, the measurement intervals Δx and Δy depend on the horizontal resolution of the measurement equipment, and in order to evaluate the surface unevenness with high precision, both Δx and Δy are preferably 5 μm or less, more preferably 2 μm or less. In addition, as described above, both the measurement ranges X and Y are preferably 500 μm or more, more preferably 750 μm or more.

Thus, in actual measurement, the function representing the elevation of the surface unevenness is obtained as a discrete function h(x, y) having M×N values. Thus, the complex amplitude ψ(x, y) obtained from the binary function h(x, y) of the surface uneven shape and the formula (5) is also obtained in the form of a discrete function, and the complex amplitude ψ(x, y) obtained from the complex amplitude ψ(x ,y) The binary function Ψ(f _x , f _y ) obtained by two-dimensional Fourier transform can also be calculated discretely by discrete Fourier transform of equation (6), as shown in equation (10) In that way, it is obtained as a discrete function.

[mathematical formula 10]

$\begin{array}{c}\mathrm{\&Psi;}(\mathrm{j\&Delta;}{f}_x,\mathrm{k\&Delta;}{f}_{\mathrm{the\; y}})=\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\mathrm{\&psi;}(x,\mathrm{the\; y})\exp \left[2\mathrm{\&pi;i}(f_{x}x+f_{\mathrm{the\; y}}\mathrm{the\; y})\right]\mathrm{dxdy}\\ \&ap;\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\underset{m=0}{\overset{m-1}{\mathrm{\&Sigma;}}}\mathrm{\&psi;}(\mathrm{m\&Delta;x},\mathrm{n\&Delta;y})\exp \left[2\mathrm{\&pi;i}(\mathrm{j\&Delta;}{f}_x\mathrm{n\&Delta;x}+\mathrm{k\&Delta;}{f}_{\mathrm{the\; y}}\mathrm{m\&Delta;y})\right]\mathrm{\&Delta;x\&Delta;y}\\ =\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\underset{m=0}{\overset{m-1}{\mathrm{\&Sigma;}}}\mathrm{\&psi;}(\mathrm{m\&Delta;x},\mathrm{n\&Delta;y})\exp \left[2\mathrm{\&pi;i}(\frac{\mathrm{jn}}{m}+\frac{\mathrm{km}}{N})\right]\mathrm{\&Delta;x\&Delta;y}\end{array}$ ...Formula (10)

Here, j in Formula (10) 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. In addition, Δf _x and Δf _y are the frequency intervals in the x-direction and y-direction, respectively, and are defined by Equation (11) and Equation (12).

[mathematical formula 11]

$\mathrm{\&Delta;}{f}_x\&equiv;\frac{1}{\mathrm{M\&Delta;x}}$ ...Formula (11)

[mathematical formula 12]

$\mathrm{\&Delta;}{f}_{\mathrm{the\; y}}\&equiv;\frac{1}{\mathrm{M\&Delta;y}}$ ...Formula (12)

The two-dimensional power spectrum H(f _x ,f _y ) can be obtained by taking the absolute value of the discrete function Ψ(f _x ,f _y ) obtained according to formula (10) to the second power, as shown in formula (13): be asked.

[mathematical formula 13]

$h(\mathrm{j\&Delta;}{f}_x,\mathrm{k\&Delta;}{f}_{\mathrm{the\; y}})=|\mathrm{\&Psi;}(\mathrm{j\&Delta;}{f}_x,\mathrm{k\&Delta;}{f}_{\mathrm{the\; y}}){|}^2={\left(\mathrm{\&Delta;x\&Delta;y}\right)}^2|\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\underset{m=0}{\overset{m-1}{\mathrm{\&Sigma;}}}\mathrm{\&psi;}(\mathrm{m\&Delta;x},\mathrm{n\&Delta;y})\exp \left[2\mathrm{\&pi;i}(\frac{\mathrm{jn}}{m}+\frac{\mathrm{km}}{N})\right]{|}^2$ ...Formula (13)

The two-dimensional power spectrum H(f _x , f _y ) obtained in the form of a discrete function also represents the spatial frequency distribution of the complex amplitude calculated from the height of the surface unevenness of the antiglare film. In addition, the anti-glare film is isotropic, therefore, the two-dimensional discrete function H(f _x ,f _y ) representing the two-dimensional power spectrum of the complex amplitude can also be obtained by only depending on the distance f from the origin (0,0) The one-dimensional discrete function H(f) represents. When solving the one-dimensional discrete function H(f) from the two-dimensional discrete function H(f _x , f _y ), it is only necessary to calculate the rotation average in the same manner as in Equation (9). The discrete rotational average of the two-dimensional discrete function H(f _x , f _y ) can be calculated using formula (14). The power spectrum calculation method described above is a method for calculating the one-dimensional power spectrum represented by the one-dimensional discrete function H(f).

[mathematical formula 14]

$h\left(\mathrm{l\&Delta;f}\right)=\frac{\underset{k=-N/2}{\overset{N/2-1}{\mathrm{\&Sigma;}}}\underset{j=-m/2}{\overset{m/2-1}{\mathrm{\&Sigma;}}}h(\mathrm{j\&Delta;}{f}_x,\mathrm{k\&Delta;}{f}_{\mathrm{the\; y}})[\mathrm{\&Theta;}(f_{\mathrm{jk}}-(l-\frac{1}{2})\mathrm{\&Delta;\; f})-\mathrm{\&Theta;}(f_{\mathrm{jk}}-(l+\frac{1}{2}\mathrm{\&Delta;f}))]}{\underset{k=-N/2}{\overset{N/2-1}{\mathrm{\&Sigma;}}}\underset{j=-m/2}{\overset{m/2-1}{\mathrm{\&Sigma;}}}[\mathrm{\&Theta;}(f_{\mathrm{jk}}-(l-\frac{1}{2})\mathrm{\&Delta;\; f})-\mathrm{\&Theta;}(f_{\mathrm{jk}}-(l+\frac{1}{2}\mathrm{\&Delta;f}))]}$ ...Formula (14)

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 an interval of distance from the origin, and Δf=(Δf _x +Δf _y )/2. In addition, Θ(x) is a unit step (Heaviside) function defined by equation (15). f _jk is the distance from the origin at (j,k), which can be calculated by formula (16).

[mathematical formula 15]

$\mathrm{\&Theta;}\left(x\right)\&equiv;\left\{\begin{array}{cc}0& (x<0)\\ 1& (x\&Greater\; Equal;0)\end{array}\right.$ ...Formula (15)

[mathematical formula 16]

$f_{\mathrm{jk}}\&equiv;\sqrt{{\left(\mathrm{j\&Delta;}{f}_x\right)}^2+{\left(\mathrm{k\&Delta;}{f}_{\mathrm{the\; y}}\right)}^2}$ ...Formula (16)

The calculation shown in formula (14) will be described with reference to FIG. 5 . The function Θ(f _jk -(l-1/2)Δf) is 0 when f _jk is less than (l-1/2)Δf, and is 1 when f _jk is (l-1/2)Δf or more. The function Θ (f _jk -(l+1/2)Δf) is 0 when f _jk is less than (l+1/2)Δf, and is 1 when f _jk is (l+1/2)Δf or more. Therefore, the formula ( Θ(f _jk -(l-1/2)Δf)-Θ(f _jk -(l+1/2)Δf) in 14) is only when f _jk is (l-1/2)Δf or more and less than ( 1-1/2) Δf is 1, otherwise it is 0. Here, f _jk is the distance from the origin O (f _x =0, f _y =0) in the frequency space, therefore, the denominator of the formula (14) calculates the distance f _jk from the origin O in (l-1 /2) The number of all points (black dots in FIG. 5 ) at positions above Δf and less than (1+1/2)Δf. In addition, what the _numerator of formula (14) calculates is the H(f The total value of _x ,f _y ) (the total value of H(f _x ,f _y ) at the black circle point in FIG. 5 ).

In general, the one-dimensional power spectrum obtained by the above method includes disturbances in the measurement. Here, when calculating the one-dimensional power spectrum, in order to eliminate the influence of the interference, it is preferable to measure the elevations of the surface irregularities at multiple locations on the anti-glare film, and to calculate the one-dimensional power spectrum obtained from the elevations of the various surface irregularities. The average value is used as the one-dimensional power spectrum H(f). The number of sites for measuring the height of the surface unevenness on the anti-glare film is preferably 3 or more, more preferably 5 or more.

FIG. 6 shows H(f) of the one-dimensional power spectrum of the complex amplitude calculated from the elevations of the thus-obtained surface irregularities. The one-dimensional power spectrum H(f) in FIG. 6 is obtained by averaging the one-dimensional power spectra obtained from the elevations of the surface irregularities at five different locations on the antiglare film.

The antiglare film of the present invention is characterized in that the intensity H(0.002) of the one-dimensional power spectrum H(f) of the complex amplitude calculated from the elevation of the surface unevenness at the spatial frequency 0.002 μm ^-1 is related ^to the spatial frequency 0.01 μm -1 The ratio H(0.01)/H(0.002) of the intensity H(0.01) at ¹ is 0.02 to 0.6, and the ratio H(0.02) of the intensity H(0.002) to the intensity H(0.02) at a spatial frequency of 0.02 μm ^-1 )/H(0.002) is not less than 0.005 and not more than 0.05, and the ratio H(0.04)/H(0.002) of the intensity H(0.002) to the intensity H(0.04) at a spatial frequency of 0.04 μm ⁻¹ is not less than 0.0005 and not more than 0.01. Here, the one-dimensional power spectrum H(f) is obtained in the form of a discrete function. Therefore, in order to obtain the intensity H(f ₁ ) at a specific spatial frequency f ₁ , interpolation is performed as shown in equation (17). Just do the calculation.

[mathematical formula 17]

$h\left(f_1\right)=\left[\frac{h(l_1\mathrm{\&Delta;\; f}+\mathrm{\&Delta;\; f})-h\left(l_1\mathrm{\&Delta;\; f}\right)}{\mathrm{\&Delta;\; f}}\right](f_1-l_1\mathrm{\&Delta;\; f})+h\left(l_1\mathrm{\&Delta;f}\right)$ ...Formula (17)

The anti-glare film of the present invention can satisfactorily prevent occurrence of whitening and glare by making the intensity ratios at the above-mentioned specific spatial frequencies within the specified ranges, and utilizing the synergistic effect with the haze and reflectance ratios described later, and Excellent anti-glare properties can be exhibited. In order to exhibit the above effect more effectively, the ratio H(0.01)/H(0.002) is preferably 0.02 to 0.6, more preferably 0.03 to 0.3. Likewise, the ratio H(0.02)/H(0.002) is preferably 0.005 to 0.05, more preferably 0.007 to 0.04, and the ratio H(0.04)/H(0.002) is preferably 0.0005 to 0.01, and further Preferably, it is 0.001 or more and 0.005 or less.

When the ratio H(0.01)/H(0.002) is less than the above range, about 100 μm (equivalent to 0.01 μm in terms of spatial frequency) is advantageous for the anti-glare effect when the anti-glare film is viewed obliquely (over 30°) ^{- 1} ) The periodic optical change is small, and the anti-glare property is insufficient. When the ratio H(0.01)/H(0.002) exceeds the above range, the optical change at a period of about 100 μm becomes too large, and the surface roughness of the anti-glare film tends to increase, which tends to increase the haze. Not preferred.

When the ratio H(0.02)/H(0.002) is lower than the above range, about 50 μm (equivalent to 0.02 in terms of spatial frequency) is favorable for the anti-glare effect when the anti-glare film is observed from an oblique direction (10°-30°). μm ^-1 ) periodic optical change is small, and the anti-glare property is insufficient. When the ratio H(0.02)/H(0.002) exceeds the above-mentioned range, the optical change at a period of about 50 μm becomes too large, causing glare.

When the ratio H(0.04)/H(0.002) is less than the above range, the anti-glare effect is favorable when the anti-glare film is viewed from the front (0°-10°) at about 25 μm (equivalent to 0.04 μm in terms of spatial frequency) ^-1 ) Periodic optical changes are small, and the anti-glare property is insufficient. When the ratio H(0.04)/H(0.002) exceeds the above range, scattering due to short-period optical changes at about 25 μm is enhanced, and whitening tends to occur.

[total haze, surface haze]

In order to exhibit anti-glare properties and prevent whitening, the anti-glare film of the present invention has a total haze of 0.1% to 3% with respect to vertically incident light, and a surface haze of 0.1% to 2% inclusive. membrane. The total haze of the antiglare film can be measured based on the method shown in JIS K7136. An image display device provided with an anti-glare film having a total haze or a surface haze of less than 0.1% is not preferable since sufficient anti-glare properties cannot be exhibited. In addition, when the total haze exceeds 3%, or when the surface haze exceeds 2%, since the image display device in which the anti-glare film is arranged will cause whitening, it is not preferable. Such an image display device also suffers from insufficient contrast.

The lower the internal haze obtained by subtracting the surface haze from the total haze, the more preferable. An image display device provided with an anti-glare film having an internal haze higher than 2.5% tends to lower contrast.

[Transmission clarity (sharpness) Tc, reflection clarity Rc (45) and reflection clarity Rc (60)]

The antiglare film of the present invention preferably has a sum Tc of transmitted clarity obtained under the following measurement conditions of 375% or more. The sum Tc of the transmission sharpness can be obtained by measuring the image sharpness separately using a method based on JIS K 7105 using an optical comb of a specified width, and calculating the sum thereof. Specifically, using five kinds of optical combs with a width ratio of 1:1 between the dark part and the bright part and whose widths are 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm, the image sharpness is measured respectively, and then the Take out its addition and set it as Tc. When an anti-glare film having a Tc of less than 375% is disposed on a higher-definition image display device, glare may easily occur. As far as the upper limit of Tc is concerned, it can be selected within the range of 500% or less of its maximum value, but if the Tc is too high, an image display device whose anti-glare property is easily reduced when viewed from the front will be obtained, so the Tc Preferably, it is, for example, 450% or less.

It is preferable that the reflection clarity Rc(45) of the antiglare film of this invention measured by the incident light of an incident angle of 45 degrees is 180 % or less. The reflection clarity Rc(45) can be measured by the method based on JIS K 7105 similarly to the above Tc, using four kinds of optical combs with a width of 0.25mm, 0.5mm, 1.0mm and 2.0mm among the above five kinds of optical combs to measure the image respectively Clarity, and calculate its addition, set as Rc(45). When Rc(45) is 180% or less, the anti-glare property when viewed from the front and oblique directions of the image display device in which such an anti-glare film is arranged becomes more favorable, and it is preferable. The lower limit of Rc(45) is not particularly limited, but is preferably, for example, 80% or more in order to suppress occurrence of whitening and glare well.

It is preferable that the reflection clarity Rc(60) of the antiglare film of this invention measured by the incident light of an incident angle of 60 degrees is 240 % or less. Except for changing the incident angle, the reflection clarity Rc(60) was measured by the method based on JIS K 7105 in the same manner as the reflection clarity Rc(45). When Rc(60) is 240% or less, the anti-glare property when viewed from an oblique direction of the image display device in which the anti-glare film is arranged becomes more favorable, and it is preferable. The lower limit of Rc(60) is not particularly limited, but is preferably, for example, 150% or more in order to more favorably suppress the occurrence of whitening and glare.

[Manufacturing method of anti-glare film]

The antiglare film of the present invention can be produced as follows, for example. The first method includes: preparing a mold for forming fine unevenness based on a predetermined pattern on the molding surface, transferring the shape of the uneven surface of the mold to a transparent support, and transferring the shape of the uneven surface The transparent support was peeled from the mold. The second method includes: preparing a composition comprising microparticles, a resin (binder) and a solvent in which the microparticles are dispersed in a resin solution, coating the composition on a transparent support, and drying as necessary, so that The thus formed coating film (coating film containing fine particles) is cured. In the second method, the coating film thickness and the aggregation state of the microparticles are adjusted according to the composition of the above-mentioned composition, the drying conditions of the above-mentioned coating film, etc., thereby exposing the microparticles on the surface of the coating film, so that the microparticles are exposed on the transparent support. Random irregularities are formed. From the viewpoint of production stability and production reproducibility of the anti-glare film, the anti-glare film of the present invention is preferably produced by the first method.

Here, the 1st method preferable as the manufacturing method of the antiglare film of this invention is demonstrated in detail.

In order to form the anti-glare layer having the surface unevenness shape with the above characteristics with high precision, it is important to prepare a mold for forming fine unevenness (hereinafter also simply referred to as "mold"). More specifically, the concave-convex shape of the surface of the mold (hereinafter also referred to as "the concave-convex surface of the mold") is formed based on a specified pattern, and in terms of the specified pattern, it is preferable that the one-dimensional power spectrum thereof has a spatial frequency of 0.002 μm ^- The ratio Γ(0.01)/Γ(0.002) of the intensity Γ(0.002) at ¹ to the intensity Γ(0.01) at the spatial frequency 0.01 μm ^-1 is 1.5 to 6, and the intensity Γ at the spatial frequency 0.002 μm ^-1 The ratio Γ(0.02)/Γ(0.002) of the intensity Γ(0.02) at the spatial frequency 0.02μm ^-1 to the intensity Γ(0.02) is 0.3 to 5, and the intensity Γ(0.002) at the spatial frequency 0.002μm ^-1 The ratio Γ(0.04)/Γ(0.002) of the intensity Γ(0.04) at a frequency of 0.04 μm ⁻¹ is 3 or more and 13 or less. Here, the "pattern" refers to image data for forming the surface concavo-convex shape of the anti-glare layer included in the anti-glare film, or a mask having a light-transmitting portion and a light-shielding portion, and is hereinafter simply referred to as a “pattern”.

First, the method of specifying the pattern for forming the surface roughness shape of the anti-glare layer which the anti-glare film of this invention has is demonstrated.

For example, a method for calculating a two-dimensional power spectrum of a pattern will be described for a case where the pattern is image data. First, after converting the image data into binarized image data of 2 gradation levels, the gradation levels are represented by a binary function g(x, y). Perform Fourier transform on the obtained binary function g(x, y) as shown in the following formula (18) to calculate the binary function G(f _x , f _y ), and then as shown in the following formula (19) , take the quadratic of the absolute value of the obtained binary function G(f _x ,f _y ), so as to calculate the two-dimensional power spectrum Γ(f _x ,f _y ). Here, x and y represent orthogonal coordinates within the image data plane. In addition, f _x and f _y represent frequencies in the x-direction and y-direction, respectively, and have dimensions of the reciprocal length.

[mathematical formula 18]

$G(f_x,f_{\mathrm{the\; y}})=\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\mathrm{g\&psi;}(x,\mathrm{the\; y})\exp \left[2\mathrm{\&pi;i}(f_{x}x+f_{\mathrm{the\; y}}\mathrm{the\; y})\right]\mathrm{dxdy}$ ...Formula (18)

π in formula (18) is pi, and i is the imaginary unit.

[mathematical formula 19]

Γ(f _x ,f _y )=|G(f _x ,f _y )| ² ...Formula (19)

This two-dimensional power spectrum Γ(f _x , f _y ) represents the spatial frequency distribution of the pattern. Usually, antiglare films are required to be isotropic, so the pattern for antiglare film production of the present invention is also isotropic. Thus, a binary function Γ(f _x ,f _y ) representing the two-dimensional power spectrum of a pattern can be represented by a unary function Γ(f) that depends only on the distance f from the origin (0,0). Next, a method for calculating the unary function Γ(f) from the binary function Γ(f _x , f _y ) will be described. First, a binary function Γ(f _x , f _y ), which is a two-dimensional power spectrum of the gradation level of a pattern, is represented by polar coordinates as in Equation (20).

[mathematical formula 20]

Γ(f _x ,f _y )=Γ(f cosθ,f sinθ)...Formula (20)

Here, θ is the declination angle in Fourier space. The one-variable function Γ(f) can be obtained by calculating the rotation average of the two-variable function Γ(fcosθ, fsinθ) expressed in polar coordinates as in Equation (21). Hereinafter, the unary function Γ(f) obtained from the rotational average of the binary function Γ(f _x , f _y ) which is the two-dimensional power spectrum of the gradation level of the pattern is also referred to as the one-dimensional power spectrum Γ(f).

[Mathematical formula 21]

$\mathrm{\&Gamma;}\left(f\right)\&equiv;\frac{1}{2\mathrm{\&pi;}}\underset{0}{\overset{2\mathrm{\&pi;}}{\&Integral;}}\mathrm{\&Gamma;}(f\cos \mathrm{\&theta;},f\sin \mathrm{\&theta;})\mathrm{d\&theta;}$ ...Formula (21)

In order to obtain the anti-glare film of the present invention with high precision, the ratio Γ of the intensity Γ (0.002) of the one ^- dimensional power spectrum of the pattern at a spatial frequency of 0.002 μm to the intensity ^Γ (0.01) at a spatial frequency of 0.01 μm (0.01)/Γ(0.002) is 1.5 to 6, the ratio Γ(0.02)/Γ of the intensity Γ(0.002) at the spatial frequency 0.002μm- ¹ to the intensity Γ(0.02) at the spatial frequency 0.02μm ^-1 (0.002) is not less than 0.3 and not more than 5, the ratio Γ(0.04)/Γ(0.002) of the intensity Γ(0.002) at the spatial frequency 0.002 μm ^-1 to the intensity Γ(0.04) at the spatial frequency 0.04 μm ^-1 is 3 Above and below 13.

When obtaining the two-dimensional power spectrum of a pattern, the binary function g(x, y) of the gray scale is usually obtained as a discrete function. In this case, the two-dimensional power spectrum may be calculated by discrete Fourier transform. The one-dimensional power spectrum of the pattern can be similarly obtained from the two-dimensional power spectrum of the pattern.

In order to make the kurtosis Rku of the roughness curve of the surface unevenness of the antiglare film be 4.9 or less to manufacture the antiglare film of the present invention, it is preferable to make the average value of the binary function g(x, y) be the binary function g(x , 35-65% of the difference between the maximum value of the binary function g(x, y) and the minimum value of the binary function g(x, y). This binary function g(x, y) is the aperture ratio of the pattern in the case of manufacturing the concave-convex surface of the mold by photolithography. For the case of manufacturing the concave-convex surface of the mold by photolithography, the aperture ratio of the pattern here is defined in advance. When the photoresist used in the photolithography method is a positive photoresist, the aperture ratio means: when image data is drawn on the coating film of the positive photoresist, the ratio is relative to the coating film. The proportion of the total surface area of the film that is exposed. On the other hand, when the photoresist used in photolithography is a negative photoresist, the aperture ratio means: when image data is drawn on the coating film of the negative photoresist, the aperture ratio is relative to the coating film of the negative photoresist. The ratio of the exposed area to the entire surface area of the cloth film. When the photolithography method is one-shot exposure, the aperture ratio refers to the ratio of the light-transmitting portion of a mask having a light-transmitting portion and a light-shielding portion. When the opening ratio of the pattern is too small or too large, the convex or concave portions of the finely uneven surface formed on the mold become sparse, and as a result, the unevenness of the surface uneven shape of the obtained anti-glare film may become sparse and the kurtosis may increase. tendency. The inventors of the present invention found that if an anti-glare film is produced from a mold having a pattern opening ratio within the above-mentioned range, it is easy to make the kurtosis Rku of the roughness curve 4.9 or less.

The antiglare film of the present invention can be obtained by making the intensity ratios of the one-dimensional power spectrum of the pattern Γ(0.01)/Γ(0.002), Γ(0.02)/Γ(0.002), and Γ(0.04)/Γ(0.002) Within the above-mentioned ranges, a desired mold is produced, and the anti-glare film of the present invention is produced by the above-mentioned first method using the mold.

In order to create a one-dimensional power spectrum pattern having such an intensity ratio, a pattern in which dots are randomly arranged, or a pattern with random brightness distribution whose shading is determined by random numbers or pseudo-random numbers generated by a computer is created in advance. A pattern (preparation pattern) from which components of a specific spatial frequency range are removed. In order to remove components in this specific spatial frequency range, the above-mentioned preliminary pattern may be passed through a band-pass filter.

In order to produce an antiglare film having an antiglare layer having a surface irregularity based on a predetermined pattern, a mold having an uneven surface for transferring the surface irregularity formed based on the predetermined pattern to a transparent support is produced. The above-mentioned first method using such a mold is an embossing method characterized by forming an antiglare layer on a transparent support.

As said embossing method, the photo embossing method using a photocurable resin, the thermal embossing method using a thermoplastic resin, etc. are mentioned. Among them, the photoembossing method is preferable from the viewpoint of productivity.

In the photoembossing method, a photocurable resin layer is formed on a transparent support (the surface of the transparent support), and the photocurable resin layer is pressed against the concave and convex surface of the mold while curing it. A method of transferring the shape of the concave-convex surface of the mold to the photocurable resin layer. The details are as follows: in the state where the photocurable resin layer formed by coating the photocurable resin on the transparent support is closely adhered to the concave-convex surface of the mold, light is irradiated from the transparent support side (the light uses a light that can curable resin curing light), so that the photocurable resin (photocurable resin contained in the photocurable resin layer) is cured, and then the transparent support formed with the cured photocurable resin layer is peeled from the mold . In the antiglare film obtained by such a manufacturing method, the photocurable resin layer after hardening becomes an antiglare layer. It should be noted that, from the viewpoint of ease of manufacture, as the photocurable resin, an ultraviolet curable resin is preferred, and in the case of using the ultraviolet curable resin, ultraviolet light is used for the light to be irradiated (hereinafter, the ultraviolet curable resin is used as The embossing method of photocurable resin is called "UV embossing method"). In order to manufacture the antiglare film integrated with a polarizing film, using a polarizing film as a transparent support body, what is necessary is just to replace a transparent support body with a polarizing film in the embossing method demonstrated here.

The type of ultraviolet curable resin used in the UV embossing method is not particularly limited, and an appropriate resin can be selected and used from commercially available resins according to the type of transparent support to be used and the type of ultraviolet rays. Such an ultraviolet curable resin is a concept including monomers (polyfunctional monomers), oligomers, polymers, and mixtures thereof that are photopolymerized by irradiation with ultraviolet rays. In addition, by using in combination a photoinitiator appropriately selected according to the type of ultraviolet curable resin, a resin that can be cured also by visible light having a wavelength longer than ultraviolet rays can also be used. Preferred examples and the like of the ultraviolet curable resin will be described later.

As the transparent support used in the UV embossing method, for example, glass, a plastic film, or the like can be used. As the plastic film, any one having appropriate transparency and mechanical strength can be used. Specific examples include: cellulose acetate resins such as TAC (cellulose triacetate); acrylic resins; polycarbonate resins; polyester resins such as polyethylene terephthalate; Transparent resin film made of polyolefin resin such as acrylic. 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, more preferably 10 to 60 μm. When the thickness of the transparent support is within this range, an anti-glare film having sufficient mechanical strength tends to be obtained, and an image display device including the anti-glare film is less likely to be dazzled.

On the other hand, the thermal embossing method is a method in which a transparent resin film made of a thermoplastic resin is pressed against a mold concave-convex surface in a heated and softened state, and the surface concave-convex shape of the mold concave-convex surface is transferred to the transparent resin film. The transparent resin film used in the heat embossing method may be any film as long as it is substantially optically transparent, and specifically, the materials listed as the transparent resin film used in the UV embossing method are mentioned.

Hereinafter, the method of manufacturing the mold used for the embossing method is demonstrated.

Regarding the manufacturing method of the mold, as long as the molding surface of the mold is made to be able to transfer the above-mentioned surface unevenness formed based on the specified pattern on the transparent support (the anti-glare layer that can form the surface unevenness formed based on the specified pattern ) is not particularly limited, but in order to manufacture the anti-glare layer with the concave-convex shape of the surface with high precision and good reproducibility, photolithography is preferred. Further, the photolithography method preferably includes the following steps: [1] first plating step, [2] first polishing step, [3] photosensitive resin film forming step, [4] exposure step, [5] development step , [6] First etching step, [7] Photosensitive resin film peeling step, [8] Second etching step, [9] Second plating step, and [10] Second polishing step.

FIG. 7 schematically shows a preferred example of the first half of the mold manufacturing method. Fig. 7 schematically shows the cross section of the mold in each process. Hereinafter, each process of the manufacturing method of the mold for antiglare film manufacturing of this invention is demonstrated in detail with reference to FIG. 7. FIG.

[1] The first plating process

First, a base material (base material for mold) to be used for mold production is prepared, and copper plating is performed on the surface of the base material for mold. By performing copper plating on the surface of the base material for molds in this way, the adhesiveness and glossiness of the chromium plating in the 2nd plating process mentioned later can be improved. Copper plating has a high coating property and a strong smoothing effect, so it is possible to fill minute unevenness, cavities, etc. of the base material for a mold to form a flat and glossy surface. Thus, by performing copper plating on the surface of the base material for the mold in this way, even if chrome plating is performed in the second plating step described later, it is possible to eliminate the defects on the chrome-plated surface that are thought to be caused by the micro unevenness and voids in the base material. rough. Therefore, even if a surface irregularity shape (fine uneven surface shape) based on a predetermined pattern is formed on the molding surface of the base material for a mold, deviations caused by the influence of the surface of the base (base material for mold) such as minute unevenness and cavities can be sufficiently prevented.

As copper used in the copper plating in the first plating step, a pure metal of copper may be used, or an alloy (copper alloy) mainly composed of copper may be used. Therefore, "copper" used for copper plating is a concept including copper and copper alloys. Copper plating may be electroplating or electroless plating, but it is preferable to use electroplating for copper plating in the first plating step. Furthermore, the preferred plating layer in the first plating step is not only a plating layer consisting of a copper plating layer, but a plating layer formed by laminating a copper plating layer and a plating layer made of a metal other than copper.

If the plating layer formed by copper plating on the surface of the base material for the mold is too thin, the influence of the base surface (micro unevenness, voids, cracks, etc.) cannot be completely eliminated, so the thickness is preferably 50 μm or more. The upper limit of the plating thickness is not critical, but it is preferably about 500 μm or less in terms of cost and the like.

The base material for a mold is preferably a base material made of a metal material. Furthermore, aluminum, iron, etc. are preferable as a material of this metal material from a viewpoint of cost. Furthermore, it is particularly preferable to use a lightweight aluminum base material as the base material for the mold from the viewpoint of the ease of handling the base material for the mold. It should be noted that the aluminum and iron here do not need to be pure metals, and may be alloys mainly composed of aluminum or iron.

The shape of the base material for molds should just be an appropriate shape with respect to the manufacturing method of the antiglare film of this invention. Specifically, it can be selected from a flat substrate, a cylindrical substrate, a cylindrical (tubular) substrate, and the like. When continuously producing the antiglare film of the present invention, it is preferable that the mold is cylindrical. Such a mold can be produced from a cylindrical mold base material.

[2] The first grinding process

In the next first polishing step, the surface (plated layer) of the base material for a metal mold that has been copper-plated in the above-mentioned first plating step is polished. In the method for producing a mold used in the method for producing an antiglare film of the present invention, it is preferable to polish the surface of the base material for a mold to a state close to a mirror surface through the first polishing step. Commercially available products such as flat bases and cylindrical bases used as bases for molds are often subjected to mechanical processing such as cutting and grinding in order to achieve the desired accuracy, and as a result, the base material for molds Fine processing traces remain on the surface. Thus, even if a plating (preferably copper plating) layer is formed by the 1st plating process, the said processing mark may remain. Moreover, even if plating in the 1st plating process is performed, the surface of the base material for molds is not necessarily completely smooth. That is, even if the steps [3] to [10] described later are performed on a base material for a mold having such a surface on which deep processing traces and the like remain, the surface unevenness shape of the obtained mold surface may be different from the surface unevenness based on a predetermined pattern. There are differences in shape, or may include unevenness caused by processing traces, etc. When the anti-glare film is produced using a mold with residual effects such as processing traces, the desired optical properties such as anti-glare property may not be fully exhibited, resulting in unexpected effects.

The polishing method used in the first polishing step is not particularly limited, and the polishing method can be selected according to the shape and properties of the base material for a mold to be polished. Specific examples of the polishing method applicable to the first polishing step include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method. However, as the mechanical polishing method, any method of superfinishing, buffing, fluid polishing, buff polishing, and the like can be used. In addition, the surface of the mold base material can also be made into a mirror surface by performing mirror surface cutting using a cutting tool in the polishing step. In terms of the material and shape of the cutting tool at this time, cemented tools, CBN tools, ceramic tools, diamond tools, etc. can be used depending on the type of material (metal material) of the base material for the mold, but from the viewpoint of machining accuracy, Preference is given to using diamond tools. The surface roughness after grinding is represented by centerline average roughness Ra based on JIS B 0601, and is preferably 0.1 μm or less, more preferably 0.05 μm or less. When the centerline average roughness Ra after grinding is larger than 0.1 μm, the effect of the surface roughness may remain on the concave-convex surface of the finally obtained mold. In addition, the lower limit of the centerline average roughness Ra is not particularly limited. Therefore, the lower limit may be determined from the viewpoint of processing time (polishing time) in the first polishing step and processing cost.

[3] Photosensitive resin film forming process

Hereinafter, the photosensitive resin film forming process will be described with reference to FIG. 7 .

In the photosensitive resin film forming step, the solution (photosensitive resin solution), heated and dried to form a photosensitive resin film (photoresist film). FIG. 7 schematically shows a state where the photosensitive resin film 50 is formed on the surface 41 of the mold base material 40 ( FIG. 7( b )).

As the photosensitive resin, a conventionally known photosensitive resin can be used, and a resin commercially available as a photoresist may be used as it is, or after being purified by filtration or the like if necessary. For example, as a negative-type photosensitive resin having a property that the photosensitive part is cured, monomers or prepolymers of (meth)acrylates having acryloyl or methacryloyl groups in the molecule, bisazide ( Bisazide) and diene rubber mixture, polyvinyl cinnamate compounds, etc. In addition, as a positive-type photosensitive resin having a property that the photosensitive part is eluted by development and only the non-photosensitive part remains, phenolic resins, novolac type resins, and the like can be used. Such a positive-type or negative-type photosensitive resin can also be easily obtained from the market as a positive-type photoresist or a negative-type photoresist. In addition, various additives such as a sensitizer, a development accelerator, an adhesion improver, and a coatability improver may be added to the photosensitive resin solution as needed, and such additives may be mixed with a commercially available photoresist Use it as a photosensitive resin solution after mixing.

In order to apply these photosensitive resin solutions to the surface 41 of the base material 40 for a mold, it is preferable to select the most suitable solvent from the viewpoint of forming a smoother photosensitive resin film, and to use a solvent in which the photosensitive resin is dissolved And dilute the obtained photosensitive resin solution. Such a solvent can be selected according to the kind of photosensitive resin and its solubility. Specifically, it can be selected from, for example, cellosolve-based solvents, propylene glycol-based solvents, ester-based solvents, alcohol-based solvents, ketone-based solvents, and highly polar solvents. In the case of using a commercially available photoresist, the most suitable photoresist can be selected according to the type of solvent contained in the photoresist or through appropriate preliminary experiments, and can be used as a photosensitive resin solution.

As a method of coating the photosensitive resin solution on the mirror-polished surface of the base material for the mold, it can be selected from the following known methods according to the shape of the base material for the mold: meniscus coating, injection method, etc. Coating, dip coating, spin coating, roll coating, wire wound rod coating, air knife coating, knife coating, curtain coating, ring coating, etc. 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 process

The next exposure step is a step of transferring a target pattern to the photosensitive resin film 50 by exposing the photosensitive resin film 50 formed in the photosensitive resin film forming step described above. The light source used for the exposure step may be appropriately selected according to the photosensitive wavelength and sensitivity of the photosensitive resin contained in the photosensitive resin film. For example, g-rays (wavelength: 436 nm) and h-rays (wavelength: : 405nm), or i-ray (wavelength: 365nm), semiconductor laser (wavelength: 830nm, 532nm, 488nm, 405nm, etc.), YAG laser (wavelength: 1064nm), KrF excimer laser (wavelength: 248nm), ArF excimer laser (wavelength: 193nm), F2 excimer laser (wavelength: 157nm), etc. The exposure method may be a method of performing one-shot exposure using a mask corresponding to a target pattern, or a drawing method. It should be noted that the pattern of the target, as described above, is to make the intensity ratio of the one-dimensional power spectrum at the spatial frequency Γ(0.01)/Γ(0.002), Γ(0.02)/Γ(0.002) , and Γ(0.04)/Γ(0.002) are patterns in the specified preferred ranges, respectively.

In the method of manufacturing a mold, in order to form the uneven surface of the mold with higher precision, it is preferable to perform exposure in a state where a target pattern is precisely controlled on the photosensitive resin film. In order to expose in such a state, it is preferable to generate image data of a target pattern on a computer, and draw (laser draw) a pattern based on the image data on a photosensitive resin film with laser light emitted from a laser head controlled by a computer. When performing laser drawing, for example, a laser drawing apparatus commonly used in printing plate production and the like can be used. As a commercial item of such a laser drawing apparatus, LaserStream FX (manufactured by Think Laboratory, Ltd.) etc. are mentioned, for example.

FIG. 7( c ) schematically shows a state in which a 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 photoresist is used as the photosensitive resin solution), the exposed region 51 receives exposure energy to cause exchange of the photosensitive resin. Link reaction, so the solubility in the developer described later is reduced. Accordingly, in the developing step, the unexposed region 52 is dissolved by the developer, and only the exposed region 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 photoresist is used as a photosensitive resin solution), the exposed region 51 receives exposure energy and becomes photosensitive. Bond breaking of the permanent resin, etc., thereby becoming easy to dissolve in the developer solution described later. Thus, in the developing step, the exposed region 51 is dissolved by the developer, and only the unexposed region 52 remains on the surface of the base material to become the mask 60 .

[5] Development process

In the development process, when the photosensitive resin film 50 contains a negative photosensitive resin, the unexposed region 52 is dissolved by the developer solution, and the exposed region 51 remains on the base material for the mold to become a mask. 60. On the other hand, when the photosensitive resin film 50 includes a positive-type photosensitive resin, only the exposed region 51 is dissolved by the developer, and the non-exposed region 52 remains on the base material for the mold to become the mask 60. . For the base material for the mold on which a predetermined pattern is formed in the form of a photosensitive resin film, in the first etching step, the photosensitive resin film remaining on the base material for the mold is used as a mask in the first etching step described later. Play a role.

As for the developer used in the development step, an appropriate developer can be selected from conventionally known developers according to the type of photosensitive resin to be used. For example, the developing solution includes inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia dissolved therein; primary amines such as ethylamine and n-propylamine; secondary amines such as amine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium Quaternary ammonium compounds such as ammonium hydroxide and trimethylhydroxyethyl ammonium hydroxide; alkaline aqueous solutions of cyclic amines such as pyrrole and piperidine; organic solvents such as xylene and toluene.

The development method in the development step is not particularly limited, and dip development, jet development, brush development, ultrasonic development, and the like can be used.

FIG. 7( d ) schematically shows a state after performing a development process using a negative-type resin as a photosensitive resin. In FIG. 7( d ), 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. 7( e ) schematically shows a state after performing a developing process using a positive-type resin as a photosensitive resin. In FIG. 7( e ), 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] The first etching step

The first etching step is a step of etching the plated layer mainly in the maskless area on the surface of the mold base material using the photosensitive resin film remaining on the surface of the mold base material after the development process as a mask.

FIG. 8 schematically shows a preferred example of the second half of the mold manufacturing method. FIG. 8( a ) schematically shows the state after the plating layer in the maskless region is mainly etched by the etching process. Since the photosensitive resin film functions as the mask 60, the plated layer below the mask 60 is not etched, but etching proceeds from the maskless region 45 as the etching progresses. Accordingly, the plated layer located under the mask 60 is also etched near the boundary between the region where the mask 60 exists and the region 45 without the mask. In this way, the case where the plating layer under the mask 60 is also etched near the boundary between the region where the mask 60 exists and the region 45 without the mask is referred to as side etching.

The etching treatment in the first etching step is generally performed by using an etching solution such as a ferric chloride (FeCl ₃ ) solution, a copper chloride (CuCl ₂ ) solution, an alkaline etching solution (Cu(NH ₃ ) ₄ Cl ₂ ), The plating layer (metal surface) located mainly in the area without the mask 60 in the surface of the base material for the mold is etched. As the etching treatment, a strong acid such as hydrochloric acid or sulfuric acid can be used as an etching solution, and when the plated layer is formed by electroplating, the etching treatment can also be performed by reverse electrolytic etching in which a potential opposite to that during electroplating is applied. The surface irregularities formed on the base material for the mold during the etching process vary depending on the constituent material (metal material) or the type of plating of the base material for the mold, the type of photosensitive resin film, and the type of etching treatment in the etching process, etc. , cannot be generalized, but when the etching amount is 10 μm or less, it is etched substantially isotropically from the surface of the base material for a mold in contact with the etchant. The etching amount here refers to the thickness of the plating layer reduced by etching.

The etching amount in the first etching step is preferably 1 to 20 μm, more preferably 3 to 10 μm, even more preferably 5 to 8 μm. When the amount of etching is less than 1 μm, the surface unevenness is hardly formed on the mold, and the obtained mold has an almost flat surface, so even if the mold is used to manufacture an antiglare film, the resulting antiglare film will hardly have Surface bumpy shape. On the other hand, an image display device provided with such an anti-glare film cannot exhibit sufficient anti-glare properties. In addition, when the amount of etching is too large, it is easy to cause a large difference in height of the concave-convex surface of the finally obtained mold. Even if the anti-glare film is produced using this mold, there is a possibility that the occurrence of whitening cannot be sufficiently prevented in an image display device provided with the anti-glare film. The etching treatment in the etching step may be performed by only one etching treatment, or may be divided into two or more etching treatments. However, when the etching process is divided into two or more times, it is preferable that the total amount of etching in the two or more times of etching processes is 1 to 20 μm.

[7] Photosensitive resin film peeling process

The next step of peeling off the photosensitive resin film is a step of removing the photosensitive resin film remaining on the base material for the mold which functions as the mask 60 in the first etching process. The photosensitive resin film on the material is completely removed. In the photosensitive resin film peeling process, it is preferable to dissolve the photosensitive resin film using a peeling liquid. As the stripping liquid, a solution prepared by changing the concentration, pH, and the like of the materials listed as the developer can be used. Alternatively, the photosensitive resin film may be peeled by changing the temperature, immersion time, and the like in the image development process using the same solution as the developer used in the image development process. In the step of peeling the photosensitive resin film, there is no particular limitation on the contact method (peeling method) between the stripping liquid and the base material for the mold, and immersion peeling, spray peeling, brush peeling, ultrasonic peeling, etc. can be used.

FIG. 8( b ) schematically shows a state where the photosensitive resin film used as the mask 60 in the first etching step is completely dissolved and removed by the photosensitive resin film peeling step. The first surface unevenness 46 is formed on the surface of the mold base material by the mask 60 made of a photosensitive resin film and etching.

[8] Second etching step

The second etching step is a step for passivating the first surface unevenness 46 formed in the first etching step by further etching treatment (second etching treatment). By this 2nd etching process, at the 1st surface uneven shape 46 formed by the 1st etching process, the part where the surface inclination is sharp disappears (hereinafter, the case where the surface inclination is sharp in such a surface uneven shape is passivated called "shape passivation"). Fig. 8 (c) shows the following state: by utilizing the second etching process to make the first surface unevenness 46 of the base material 40 for the mold passivate in shape, thereby, the part with a sharp surface inclination is passivated, forming a smooth surface. The second surface concave-convex shape 47 whose surface is inclined. The mold obtained by performing the second etching treatment as described above has the effect of making the optical characteristics of the antiglare film of the present invention manufactured using the mold more ideal.

As the second etching treatment in the second etching step, etching treatment using the same etching solution as in the first etching step and reverse electrolytic etching may be employed. The degree of passivation of the shape after the second etching process (the degree of disappearance of the portion with a sharp surface inclination in the surface unevenness after the first etching process) depends on the material of the base material for the mold, the method of the second etching treatment, and the degree of elimination after the first etching process. The size and depth of the unevenness of the surface obtained by the etching process vary, so it cannot be generalized, but the most important factor in controlling the passivation (the degree of shape passivation) is the amount of etching in the second etching process . The etching amount here is expressed by the thickness of the base material cut by the second etching process as in the case of the first etching process. If the amount of etching in the second etching process is small, the effect of passivating the shape of the surface unevenness obtained in the first etching process will be insufficient. For this reason, whitening may occur in an anti-glare film manufactured using a mold whose shape is not sufficiently passivated. On the other hand, if the amount of etching in the second etching process is too large, the unevenness of the surface uneven shape formed in the first etching process will almost disappear, and a mold having a nearly flat surface may be obtained. An anti-glare film produced using such a mold having an almost flat surface may have insufficient anti-glare properties. Therefore, the etching amount of the second etching treatment is preferably within a range of 1 to 50 μm, more preferably within a range of 6 to 21 μm, and even more preferably within a range of 12 to 15 μm. Also about the second etching process, similarly to the first etching process, it may be performed by one etching process, or may be divided into two or more etching processes. However, when the etching process is divided into two or more times, it is preferable that the total amount of etching in the two or more times of etching processes is 1 to 50 μm.

[9] Second plating step

In the second plating step, plating is performed on the surface of the base material for a mold that has passed through the steps [6] and [7] above, preferably the base material for a mold that has passed the steps [6] to [8] above. (Preferably chrome plating described later). By performing the second plating step, while passivating the surface irregularities 47 of the base material for a mold, the surface of the mold can be protected by this plating. FIG. 8( d) shows a state where the surface roughness is passivated (mold roughness surface 70 ) by forming a chromium plating layer 71 on the second surface roughness 47 formed by the second etching process as described above. .

As the plated layer formed in the second plating step, chrome plating is preferable in terms of being glossy, having high hardness, having a small coefficient of friction, and being able to obtain good releasability. Among chrome platings, chrome plating exhibiting good gloss, such as so-called glossy chrome plating and decorative chrome plating, is particularly preferable. Chromium plating is usually performed by electrolysis, and as the plating bath, an aqueous solution containing anhydrous chromic acid (CrO ₃ ) and a small amount of sulfuric acid can be used as a plating solution. By adjusting the current density and electrolysis time, the thickness of the chromium plating layer can be controlled.

By performing chrome plating on the surface irregularities of the surface of the base material for the mold after the second etching treatment, it is possible to obtain a mold in which the shape is passivated and the surface hardness thereof is improved. The most important factor in controlling the degree of shape passivation at this time is the thickness of the chrome plating layer. If the thickness is thin, the degree of shape passivation is insufficient, and the antiglare film obtained by using such a mold may be whitened. On the other hand, if the thickness of the chrome plating layer is too thick, the anti-glare property will become insufficient. The inventors of the present invention have found that it is effective to manufacture a mold so that the thickness of the chrome-plated layer falls within a specified range for an anti-glare film for an image display device capable of sufficiently preventing occurrence of whitening and having excellent anti-glare properties. . That is, the thickness of the chromium plating layer is preferably within a range of 2 to 10 μm, more preferably within a range of 5 to 10 μm.

The chromium-plated layer formed through the second plating step is preferably formed so as to have a Vickers hardness of 800 or higher, and more preferably formed so as to have a Vickers hardness of 1,000 or higher. When the Vickers hardness of the chrome-plated layer is less than 800, the durability of the mold tends to decrease when the anti-glare film is produced using a mold.

[10] Second grinding process

The final stage of mold production is a second polishing step of polishing the surface (chrome-plated layer) of the base material for a mold that has been plated with chromium in the above-mentioned second plating step. Chromium plating has luster, high hardness, low coefficient of friction, and good mold release properties, but due to high internal stress when forming the chrome plating layer, it will cause microcracks on the surface. In the manufacturing method of the mold used in the method of manufacturing the anti-glare film of the present invention, it is preferable to eliminate the slight roughness of the surface shape caused by the microcracks of the chrome plating through the second polishing step. When an anti-glare film is produced using a mold with a rough surface shape caused by chrome-plated microcracks, there is a possibility that scattering on the surface will increase and whitening may occur. In addition, when the occurrence density of microcracks is distributed, the anti-glare film produced using the mold has strong scattering parts and weak scattering parts, which may cause unevenness.

The polishing method suitable for the second polishing step is preferably a method of selectively polishing only the roughness of the surface shape caused by microcracks without slightly affecting the uneven surface 70 of the mold formed in the second plating step. Specific examples of such a polishing method include buffing, a fluid polishing method, a sandblasting polishing method, and the like. The amount of polishing that is the amount by which the chromium plating layer is reduced in the second polishing step is preferably not less than 0.03 μm and not more than 0.2 μm. When the amount of polishing is less than 0.03 μm, the effect of eliminating the roughness of the surface shape due to microcracks becomes insufficient. On the other hand, when the amount of grinding exceeds 0.2 μm, flat areas are generated on the uneven surface 70 of the mold. When an anti-glare film is produced using a mold having a flat region, there is a possibility that the anti-glare property may become insufficient.

Hereinafter, the said optical embossing method preferable as a method for manufacturing the antiglare film of this invention is demonstrated. As described above, the UV embossing method is particularly preferable as the photo embossing method, but here, the embossing method using an active energy ray-curable resin will be specifically described.

In order to continuously manufacture the antiglare film of the present invention and under the situation of producing the antiglare film of the present invention by the optical embossing method, preferably include the following steps:

[P1] Coating process: Coating a coating liquid containing an active energy ray-curable resin on the continuously conveyed transparent support to form a coating layer;

[P2] Main curing step: In a state where the surface of the mold is pressed against the surface of the coating layer, active energy rays are irradiated from the side of the transparent support.

In addition, in the case of producing the antiglare film of the present invention by the optical embossing method, it is more preferable to include the following steps:

[P3] Pre-curing step: After the coating step [P1] and before the curing step [P2], the end regions on both sides in the width direction of the coating layer are irradiated with active energy rays.

Hereinafter, each step will be described in detail with reference to the drawings. FIG. 9 schematically shows a preferred example of the manufacturing apparatus used in the manufacturing method of the anti-glare film of the present invention. Arrows in FIG. 9 indicate the conveyance direction of the film or the rotation direction of the roll.

[P1] Coating process

In the coating step, a coating liquid containing an active energy ray-curable resin is coated on the transparent support to form a coating layer. In the coating process, as shown in FIG. 9 , a coating liquid containing an active energy ray-curable resin composition is coated on the coating area 83 with respect to the transparent support 81 led out from the lead-out roller 80 .

The coating of the coating liquid on the transparent support body 81 can be performed by, for example, a gravure coating method, a micro gravure coating method, a bar coating method, a knife coating method, an air knife coating method, a lick coating method, a die coating method, etc. .

(transparent support)

The transparent support body 81 should just be a light-transmitting support body, for example, glass, a plastic film, etc. can be used. As a plastic film, what is necessary is just to have moderate transparency and mechanical strength. Specifically, any of the supports listed above as transparent supports for the UV embossing method can be used. Moderately flexible material.

Various surface treatments may be applied to the surface of the transparent support 81 (coating layer side surface) for the purpose of improving the applicability of the coating liquid and improving the adhesiveness between the transparent support and the coating layer. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, acid surface treatment, alkali surface treatment, and ultraviolet irradiation treatment. In addition, another layer such as an undercoat layer may be formed on the transparent support 81 and a coating liquid may be applied on the other layer.

In addition, when an antiglare film integrated with a polarizing film is produced as the antiglare film of the present invention, in order to improve the adhesiveness between the transparent support and the polarizing film, it is preferable to treat the transparent support with various surface treatments in advance. The surface (the surface opposite to the coating layer) is hydrophilized. This surface treatment can also be performed after manufacture of an anti-glare film.

(coating solution)

The coating liquid contains an active energy ray-curable resin, and usually further contains a photopolymerization initiator (radical polymerization initiator). Various additives such as translucent fine particles, solvents such as organic solvents, leveling agents, dispersants, antistatic agents, antifouling agents, and surfactants may be contained as needed.

(1) Active energy ray curable resin

As the active energy ray curable resin, for example, a resin containing a polyfunctional (meth)acrylate compound can be preferably used. The polyfunctional (meth)acrylate compound is a compound having at least two (meth)acryloyloxy groups in the molecule. Specific examples of polyfunctional (meth)acrylate compounds include ester compounds of polyhydric alcohol and (meth)acrylic acid, urethane (meth)acrylate compounds, polyester (meth)acrylic acid A polyfunctional polymerizable compound containing two or more (meth)acryloyl groups, such as an ester compound and an epoxy (meth)acrylate compound, etc.

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, Propylene Glycol, Butylene Glycol, Pentylene Glycol, Hexylene Glycol, Neopentyl Glycol, 2-Ethyl-1,3-Hexanediol, 2,2'-Diethanol Thio, 1,4- Dihydric alcohols such as cyclohexanedimethanol; trihydric or higher alcohols such as trimethylolpropane, glycerol, pentaerythritol, diglycerol, dipentaerythritol, and ditrimethylolpropane.

As the esterified product of polyhydric alcohol and (meth)acrylic acid, specific examples include: ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di( Meth)acrylate, Neopentyl Glycol Di(meth)acrylate, Trimethylolpropane Tri(meth)acrylate, Trimethylolethane Tri(meth)acrylate, Tetramethylolmethane Tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tri( Meth)acrylate, Pentaerythritol tetra(meth)acrylate, Glycerin tri(meth)acrylate, Dipentaerythritol tri(meth)acrylate, Dipentaerythritol tetra(meth)acrylate, Dipentaerythritol penta(methyl)acrylate ) acrylate, dipentaerythritol hexa(meth)acrylate.

As a urethane (meth)acrylate compound, the urethanation reaction product of the organic isocyanate which has several isocyanate groups in 1 molecule, and the (meth)acrylic acid derivative which has a hydroxyl group is mentioned. Examples of organic isocyanates having a plurality of isocyanate groups in one molecule include hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate. Organic isocyanates having two isocyanate groups in one molecule, such as diisocyanate and dicyclohexylmethane diisocyanate, and one molecule of these organic isocyanates modified with isocyanurates, adducts, or biurets Organic isocyanates with 3 isocyanate groups, etc. Examples of (meth)acrylic acid derivatives having a hydroxyl group include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylate base) 2-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, pentaerythritol triacrylate.

As a polyester (meth)acrylate compound, polyester (meth)acrylate obtained by making hydroxyl-containing polyester and (meth)acrylic acid react is preferable. The preferably used hydroxyl-containing polyester is a hydroxyl-containing polyester obtained by esterification of a polyhydric alcohol with a carboxylic acid, or a compound having multiple carboxyl groups and/or an acid anhydride thereof. Examples of the polyol include the same polyols as those described above. Moreover, bisphenol A etc. which are phenols are mentioned other than a polyhydric alcohol. Examples of the carboxylic acid include formic acid, acetic acid, butylcarboxylic acid, benzoic acid and the like. Examples of compounds having a plurality of carboxyl groups and/or their anhydrides include maleic acid, phthalic acid, fumaric acid, itaconic acid, adipic acid, terephthalic acid, maleic anhydride, and phthalic acid. Anhydride, trimellitic acid, cyclohexanedicarboxylic anhydride, etc.

Among the polyfunctional (meth)acrylate compounds mentioned above, hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and base) acrylate, diethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, di Pentaerythritol hexa(meth)acrylate and other ester compounds; adducts of hexamethylene diisocyanate and 2-hydroxyethyl (meth)acrylate; isophorone diisocyanate and 2-hydroxyethyl (meth)acrylate Addition of ester; Addition of toluene diisocyanate and 2-hydroxyethyl (meth)acrylate; Addition of adduct modified isophorone diisocyanate and 2-hydroxyethyl (meth)acrylate and an adduct of biuret-modified isophorone diisocyanate and 2-hydroxyethyl (meth)acrylate. Furthermore, these polyfunctional (meth)acrylate compounds can be used individually or in combination of 2 or more types, respectively.

The active energy ray curable resin may contain a monofunctional (meth)acrylate compound other than the above-mentioned polyfunctional (meth)acrylate compound. Examples of monofunctional (meth)acrylate compounds include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylate, Base) tert-butyl acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, ( 2-Hydroxy-3-phenoxypropyl methacrylate, glycidyl (meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl (meth)acrylate, (meth) Cyclohexyl acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, acetyl (meth)acrylate, benzyl (meth)acrylate, 2-(meth)acrylate Ethoxyethyl ester, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide modified phenoxy Propylene oxide modified (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide modified (meth)acrylate, propylene oxide modified nonyl Phenol (meth)acrylate, Methoxydiethylene glycol (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, (meth (meth)acrylates such as dimethylaminoethyl acrylate and methoxytriethylene glycol (meth)acrylate. These compounds can be used individually or in combination of 2 or more types, respectively.

In addition, the active energy ray curable resin may contain a polymerizable oligomer. By containing the polymerizable oligomer, the hardness of the cured product can be adjusted. The polymerizable oligomer may be, for example, the above-mentioned polyfunctional (meth)acrylate compound, that is, an ester compound formed of a polyhydric alcohol and (meth)acrylic acid, a urethane (meth)acrylate compound, a polyester (meth)acrylate compound, ) oligomers such as dimers and trimers of acrylate compounds or epoxy (meth)acrylates.

As other polymerizable oligomers, urethane ( Meth)acrylate oligomers. As polyisocyanate, can enumerate: the polymer etc. of hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, as having at least 1 ( The polyhydric alcohol of meth)acryloyl group can be exemplified by the hydroxyl group-containing (meth)acrylic acid ester obtained by the esterification reaction of polyhydric alcohol and (meth)acrylic acid, and the polyhydric alcohol is, for example, 1,3-butanediol , 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, glycerin, pentaerythritol, Dipentaerythritol, etc. The polyol having at least one (meth)acryloyloxy group is a polyol in which part of the alcoholic hydroxyl groups of the polyol undergoes an esterification reaction with (meth)acrylic acid, and the alcoholic hydroxyl group remains in the molecule.

In addition, examples of other polymerizable oligomers include polyesters obtained by reacting a compound having a plurality of carboxyl groups and/or an acid anhydride thereof with a polyol having at least one (meth)acryloyloxy group. (meth)acrylate oligomers. As a compound and/or its acid anhydride which have several carboxyl groups, the same compound and/or its acid anhydride as described in the polyester (meth)acrylate of the said polyfunctional (meth)acrylate compound are mentioned. Moreover, as a polyhydric alcohol which has at least 1 (meth)acryloyloxy group, the thing similar to what was described in the said urethane (meth)acrylate oligomer is mentioned.

In addition to the polymerizable oligomers described above, examples of urethane (meth)acrylate oligomers include: isocyanates and hydroxyl-containing polyesters, hydroxyl-containing polyethers, or hydroxyl-containing ( A compound obtained by reacting hydroxyl groups of meth)acrylates. The preferably used hydroxyl-containing polyester is a hydroxyl-containing polyester obtained by esterification of a polyhydric alcohol with a carboxylic acid or a compound having multiple carboxyl groups and/or an anhydride thereof. Examples of the compound having a polyhydric alcohol, a plurality of carboxyl groups, and/or an acid anhydride thereof include the same compounds as those described in the polyester (meth)acrylate compound of the polyfunctional (meth)acrylate compound, respectively. A preferably used hydroxyl-containing polyether is a hydroxyl-containing polyether obtained by adding one or more alkylene oxides and/or ε-caprolactone to a polyol. The polyol may be the same polyol as can be used for the above-mentioned hydroxyl-containing polyester. As a preferably used hydroxyl-containing (meth)acrylate, the same hydroxyl-containing (meth)acrylate as described in the urethane (meth)acrylate oligomer of a polymerizable oligomer is mentioned. As the isocyanates, compounds having one or more isocyanate groups in the molecule are preferred, and divalent isocyanate compounds such as toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferred.

These polymerizable oligomer compounds can be used individually or in combination of 2 or more types, respectively.

(2) Photopolymerization initiator

A photopolymerization initiator can be suitably selected according to the kind of active energy rays used for antiglare 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 manufacture of the antiglare film of this invention.

As the photopolymerization initiator, for example, acetophenone-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzophenone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, triazine-based photopolymerization initiators, Photopolymerization initiators, oxadiazole-based photopolymerization initiators, and the like. In addition, as a photopolymerization initiator, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2'-bis(o-chlorophenyl)-4,4',5 ,5'-tetraphenyl-1,2'-biimidazole, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, benzil, 9,10-phenanthrenequinone, camphorquinone, benzene Methyl formylformate, titanocene compounds, etc. The usage-amount of a photoinitiator is 0.5-20 weight part normally with respect to 100 weight part of active energy ray curable resins, Preferably it is 1-5 weight part.

In order to improve the coatability of the coating liquid on the transparent support, solvents such as organic solvents may also be contained in the coating liquid. As the organic solvent, the following solvents can be selected and used in consideration of viscosity, etc.: Aliphatic hydrocarbons such as hexane, cyclohexane, and octane; Aromatic hydrocarbons such as toluene and xylene; Ethanol, 1-propanol, isopropyl Alcohols such as alcohol, 1-butanol, and cyclohexanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, and isobutyl acetate; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and other glycol ethers; ethylene glycol monomethyl ether Esterified glycol ethers such as acid esters and propylene glycol monomethyl ether acetate; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol and other cellosolves; 2-(2- Carbitols such as methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, and the like. These solvents may be used alone or in combination of two or more types as necessary. After coating, it is necessary to evaporate the above-mentioned organic solvent. For this reason, the boiling point is preferably in the range of 60°C to 160°C. In addition, it is preferable that the saturated vapor pressure at 20° C. is in the range of 0.1 kPa to 20 kPa.

When the coating liquid contains a solvent, it is preferable to provide a drying step of evaporating and drying the solvent after the above-mentioned coating step and before the first curing step. Drying can be performed by passing the transparent support 81 provided with the coating layer through the drying zone 84 as in the example shown in FIG. 9 . The drying temperature can be appropriately selected according to the type of solvent and transparent support to be used. It is usually in the range of 20°C to 120°C, but is not limited thereto. Moreover, when there are several drying furnaces, temperature can be changed for every drying furnace. The thickness of the dried coating layer is preferably 1 to 30 μm.

Thus, a laminate in which the transparent support and the coating layer are laminated can be formed.

[P2] Curing process

In this step, the coating layer is cured by irradiating active energy rays from the transparent support side while pressing the concave-convex surface (molding surface) of the mold having the desired surface concave-convex shape on the surface of the coating layer to cure the coating layer. A step of forming a cured resin layer on a support. Thereby, while curing the coating layer, it is possible to transfer the surface irregularities on the concave-convex surface of the mold to the coating layer surface. The mold used here is a cylindrical mold, which is manufactured using the cylindrical mold base material by the above-described mold manufacturing method.

This step can be as shown in FIG. 9 , for example, by using an active energy ray irradiation device 86 such as an ultraviolet irradiation device disposed on the transparent support body 81 side to apply to the coating area 83 (in the case of drying, it is a drying area 84, In the case of performing a pre-curing step described later, it is performed by irradiating active energy rays to the layered body having the coating layer passing through the pre-curing zone (which is irradiated by the active energy ray irradiation device 86 ).

First, the cylindrical mold 87 is pressed against the surface of the coating layer of the laminated body after the curing step by means of a pressing device such as a nip roller 88, and in this state, the active energy ray irradiation device 86 is used to remove the heat from the transparent layer. The coating layer 82 is cured by irradiating the active energy ray on the side of the support body 81 . 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. Use of nip rolls is effective in preventing air bubbles from entering between the coating layer and the mold of the laminate. One or more active energy ray irradiation devices may be used.

After the active energy ray irradiation, the laminate is peeled from the mold 87 using the nip roll 89 on the exit side as a fulcrum. In the obtained transparent support and the cured coating layer, the cured coating layer becomes the anti-glare layer, and the anti-glare film of the present invention is obtained. The resulting antiglare film is usually wound up by a film winding device 90 . At this time, for the purpose of protecting the anti-glare layer, a protective film made of polyethylene terephthalate, polyethylene, etc. can be bonded on the surface of the anti-glare layer through a re-peelable adhesive layer winding at the same time. In addition, the mold used here has demonstrated the case of the cylindrical mold, but the mold other than a cylindrical mold can also be used. In addition, additional active energy ray irradiation may be performed after peeling from the mold.

The active energy rays used in this step can be appropriately selected from ultraviolet rays, electron beams, near ultraviolet rays, visible light, near infrared rays, infrared rays, X-rays, etc. according to the type of 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 from the viewpoint of easy handling and high energy availability (as described above, UV embossing is preferable as the photoembossing method).

As a light source of ultraviolet rays, for example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, carbon arc lamps, electrodeless lamps, metal halide lamps, xenon arc lamps, and the like can be used. Alternatively, an ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like may 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.

In addition, examples of electron beams include Cockcroft-Walton type, Van de Graaff type, resonant transformer type, insulating core transformer type, linear type, and ground beam. An electron beam having an energy of 50 to 1000 keV, preferably 100 to 300 keV, released from various electron beam accelerators such as a Dynamitron type and a high frequency type.

When the active energy ray is ultraviolet rays, the cumulative light intensity under UVA of ultraviolet rays is preferably 100 mJ/cm ² to 3000 mJ/cm ² , more preferably 200 mJ/cm ² to 2000 mJ/cm ² . In addition, since the transparent support sometimes absorbs ultraviolet rays on the short-wavelength side, in order to suppress this absorption, the irradiation amount may be adjusted so that the integrated light amount under ultraviolet rays UVV (395 to 445 nm) in the wavelength range of visible light may be adjusted. achieve optimal. The integrated light intensity under UVV is preferably not less than 100 mJ/cm ² and not more than 3000 mJ/cm ² , more preferably not less than 200 mJ/cm ² and not more than 2000 mJ/cm ² . When the cumulative light intensity is less than 100 mJ/cm ² , the curing of the coating layer is insufficient, resulting in a reduction in the hardness of the anti-glare layer obtained, or uncured resin tends to adhere to guide rollers and the like, which tends to cause process contamination. In addition, when the cumulative light quantity exceeds 3000 mJ/cm ² , the heat radiated from the ultraviolet irradiation device may cause the transparent support to shrink and wrinkle.

[P3] Pre-curing process

This step is a step of irradiating active energy rays to end regions on both sides of the transparent support in the width direction of the coating layer prior to the curing step to precure the both end regions. Fig. 10 is a cross-sectional view schematically showing a pre-curing process. In FIG. 10 , an end region 82b in the width direction (direction perpendicular to the conveyance direction) of the coating layer is a region including the end of the coating layer and having a predetermined width from the end.

In the pre-curing step, by curing the end region in advance, the adhesion between the end region and the transparent support 81 can be further improved, thereby preventing a part of the cured resin from peeling off and falling off in the process after the curing step. polluting process. The end region 82 b can be, for example, a region of 5 mm or more and 50 mm or less from the end of the coating layer 82 .

The irradiation of the active energy ray to the end region of the coating layer is referred to FIG. 9 and FIG. 10 . 85 is performed by irradiating active energy rays to the transparent support body 81 having the coating layer 82 after passing through the coating zone 83 (drying zone 84 in the case of drying). The active energy ray irradiation device 85 may be provided on the transparent support 81 side as long as it can irradiate the end region 82b of the coating layer 82 with an active energy ray.

About the kind and light source of an active energy ray, it is the same as that of a main hardening process. When the active energy ray is an ultraviolet ray, the integrated light dose of the ultraviolet ray under UVA is preferably 10 mJ/cm ² to 400 mJ/cm ² , more preferably 50 mJ/cm ² to 400 mJ/cm ² . By irradiating with an integrated light quantity of 50 mJ/cm ² or more, deformation in the main curing process can be prevented more effectively. It should be noted that when the cumulative light intensity exceeds 400mJ/cm ² , the curing reaction proceeds excessively, and as a result, resin peeling may occur due to film thickness difference and distortion of internal stress at the boundary between the cured part and the uncured part.

[Use of the anti-glare film of the present invention]

The anti-glare film of the present invention obtained as described above can be used in image display devices, etc., and can be used as a viewing-side protective film of a viewing-side polarizing plate and bonded to a polarizing film (that is, placed on the side of an image display device). surface). Moreover, as mentioned above, when using a polarizing film as a transparent support body, in order to obtain the antiglare film integrated with a polarizing film, such an antiglare film integrated with a polarizing film can also be used for an image display apparatus. The image display device provided with the antiglare film of the present invention has sufficient antiglare properties over a wide viewing angle, and can prevent occurrence of whitening and glare well.

[Example]

Hereinafter, the present invention will be described in more detail in conjunction with examples. In the examples, "%" and "part" showing the content or the amount used are based on weight unless otherwise specified. The evaluation methods of molds or antiglare films in the following examples are as follows.

[1] Measurement of surface shape of anti-glare film

(Surface Roughness Parameters of Surface Concave and Convex Shapes)

The surface roughness parameters of the anti-glare film were measured using a surface roughness measuring instrument Surftest SJ-301 manufactured by Mitutoyo Co., Ltd. based on JIS B 0601. In order to prevent warping of the sample, measurement was performed after bonding to a glass substrate using an optically transparent adhesive so that the uneven surface was the surface.

(power spectrum of the complex amplitude calculated from the elevation of the concave-convex shape of the surface)

The elevation of the surface irregularities of the antiglare layer of the antiglare film as a measurement sample was measured using a three-dimensional microscope PLμ2300 (manufactured by Sensofar). In order to prevent warpage of the sample, the surface of the measurement sample opposite to the anti-glare layer was bonded to a glass substrate using an optically transparent adhesive, and then used for measurement. In the measurement, the magnification of the objective lens was set to 10 times, and the measurement was performed. The horizontal resolution Δx and Δy are both 1.66 μm, and the measurement area is 1270 μm×950 μm. Sampling 512 x 512 pieces (850 μm x 850 μm in terms of measurement area) data from the central part of the obtained measurement data, and obtained the surface unevenness (anti-glare) of the anti-glare film in the form of a binary function h (x, y). The elevation of the surface bump shape of the glare layer). Next, the complex amplitude in the form of the binary function ψ(x,y) is calculated from the binary function h(x,y). The wavelength λ at the time of calculating the complex amplitude is 550 nm. The binary function ψ(x, y) was subjected to discrete Fourier transform to obtain the binary function Ψ(f _x , f _y ). Square the absolute value of the binary function Ψ(f _x ,f _y ), calculate the binary function H(f _x ,f _y ) of the two-dimensional power spectrum, and calculate a function of the distance f from the origin The unary function H(f) of the dimensional power spectrum. For each sample, the elevation was measured for the surface concave-convex shape of 5 parts, and the average value of the one-dimensional power spectrum unary function H(f) calculated based on these data was used as the one-dimensional power spectrum unary function H(f) of each sample. f).

[2] Measurement of optical properties of anti-glare film

(haze)

The total haze of the anti-glare film is measured as follows: For the anti-glare film, an optically transparent adhesive is used, the surface of the measurement sample opposite to the anti-glare layer is attached to a glass substrate, and the surface of the anti-glare film attached to the glass The anti-glare film of the substrate was measured by a method based on JIS K 7136 using a haze meter "HM-150" manufactured by Murakami Color Technology Laboratory Co., Ltd. by incident light from the glass substrate side. The surface haze can be obtained by obtaining the internal haze of the anti-glare film and subtracting the internal haze from the total haze according to the following formula.

Surface haze = total haze - internal haze

The internal haze was measured as follows: a cellulose triacetate film with a haze of almost zero was attached to the anti-glare layer of the measurement sample after measuring the total haze with glycerin, and then measured by the same method as the total haze .

(transmission clarity)

The transmission clarity of the anti-glare film was measured by a method based on JIS K 7105 using an image measuring instrument "ICM-1DP" manufactured by Suga Test Instruments Co., Ltd. Also at this time, an optically transparent adhesive was used to prevent warping of the sample, and the surface of the measurement sample opposite to the anti-glare layer was bonded to a glass substrate and used for measurement. In this state, light was made to inject from the glass substrate side, and it measured. The measured value here is the total value of the values measured using five kinds of optical combs whose widths of the dark part and bright part are 0.125 mm, 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm, respectively.

(Reflection clarity measured at a light incident angle of 45°)

The reflection clarity of the anti-glare film was measured by a method based on JIS K 7105, using an image measuring instrument "ICM-1DP" manufactured by Suga Test Instruments Co., Ltd. Also at this time, an optically transparent adhesive was used to prevent warpage of the sample, and the surface of the measurement sample opposite to the anti-glare layer was bonded to a black acrylic resin substrate for measurement. In this state, light was incident at 45° from the anti-glare layer side, and the measurement was performed. The measured value here is the total value of the values measured using four kinds of optical combs whose widths of the dark portion and the bright portion are respectively 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm.

(Reflection clarity measured at a light incident angle of 60°)

The reflection clarity of the anti-glare film was measured by a method based on JIS K 7105, using an image measuring instrument "ICM-1DP" manufactured by Suga Test Instruments Co., Ltd. Also at this time, an optically transparent adhesive was used to prevent warpage of the sample, and the surface of the measurement sample opposite to the anti-glare layer was bonded to a black acrylic resin substrate for measurement. In this state, light was incident at 60° from the anti-glare layer side, and the measurement was performed. The measured value here is the total value of the values measured using four kinds of optical combs whose widths of the dark portion and the bright portion are respectively 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm.

[3] Evaluation of anti-glare performance of anti-glare film

(Visual evaluation of reflection and whitening)

In order to prevent reflection from the back of the anti-glare film, the surface of the anti-glare film opposite to the anti-glare layer of the measurement sample was attached to a black acrylic resin plate, and the anti-glare The layer side was visually observed, and the degree of reflection of the fluorescent lamp and the degree of whitening were visually evaluated. Regarding the reflection, the degree of reflection when the anti-glare film was viewed from the front and the degree of reflection when the anti-glare film was observed from an oblique direction of 30° were evaluated. Reflection and whitening were evaluated on three scales of 1 to 3, respectively, based on the following criteria.

Reflection 1: No reflection was observed.

2: Reflection is slightly observed.

3: Reflection is clearly observed.

Whitening 1: No whitening was observed.

2: Whitening is slightly observed.

3: Whitening is clearly observed.

(dazzling evaluation)

Dazzle was evaluated according to the following procedure. That is, first, a photomask having a unit lattice pattern as shown in a plan view in FIG. 11 is prepared. In this figure, a unit cell 100 has a hook-shaped chrome light-shielding pattern 101 with a line width of 10 μm formed on a transparent substrate, and the portion where the chrome light-shielding pattern 101 is not formed serves as an opening 102 . Here, the size of the cell used is 211 μm×70 μm (vertical×horizontal in the figure), so the size of the opening is 201 μm×60 μm (vertical×horizontal in the figure). A photomask is formed by arranging a plurality of illustrated unit cells vertically and horizontally.

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 facing up, and the anti-glare film 110 will be made of an adhesive to make the anti-glare layer become A sample bonded to a glass plate 117 in the form of a surface is placed on a photomask 113 . A light source 116 is arranged in the light box 115 . In this state, visual observation was performed at a position 119 about 30 cm away from the sample, and sensory evaluation was performed on the degree of glare in seven grades. Level 1 corresponds to a state in which no glare is observed at all, level 7 corresponds to a state in which glare is remarkably observed, and level 4 corresponds to a state in which glare is observed very slightly.

(evaluation of contrast)

The front and back polarizing plates were peeled off from a commercially available liquid crystal TV ["KDL-32EX550" manufactured by Sony Corporation]. Instead of these original polarizing plates, polarizing plates "Sumikaran SRDB831E" manufactured by Sumitomo Chemical Co., Ltd. were bonded to both the back side and the display side with an adhesive, and the respective absorption axes of these polarizing plates were aligned with the absorption axes of the original polarizing plates. Then, the anti-glare films shown in the following examples were bonded to the display surface side polarizing plate through an adhesive so that the uneven surface became the surface. The thus-obtained liquid crystal television was started up in a dark room, and the luminance in a black display state and a white display state were measured with a luminance meter "BM5A" manufactured by TOPCON Co., Ltd., and the contrast ratio was calculated. Here, the contrast is represented by the ratio of the luminance of a white display state to the luminance of a black display state. As a result, the ratio of the contrast measured with the antiglare film bonded to the contrast measured with the antiglare film not bonded is shown.

[4] Evaluation of patterns for anti-glare film production

The created pattern data is binarized image data of 2 gradations, and the gradations are represented by a binary discrete function g(x, y). The horizontal resolutions Δx and Δy of the discrete function g(x,y) are both 2 μm. Perform discrete Fourier transform on the binary function g(x, y) obtained to obtain the binary function G(f _x , f _y ). Square the absolute value of the binary function G(f _x ,f _y ), calculate the binary function Γ(f _x ,f _y ) of the two-dimensional power spectrum, and calculate one as a function of the distance f from the origin The unary function Γ(f) of the dimensional power spectrum.

<Example 1>

(Preparation of molds for anti-glare film production)

A material obtained by performing repeated copper plating (copper バラードめっき) on the surface of an aluminum roll (A6063 based on JIS) having a diameter of 300 mm was prepared. The repetitive copper plating consists of copper plating/thin silver plating/surface copper plating, and the thickness of the entire plating is set to about 200 μm. The copper-plated surface was mirror-polished, and a photosensitive resin was applied and dried on the polished copper-plated surface to form a photosensitive resin film. Next, a pattern in which the pattern A shown in FIG. 13 was repeatedly arranged was exposed on the photosensitive resin film with a laser, and developed. Exposure and development by laser were performed using Laser Stream FX (manufactured by Think Laboratory Co., Ltd.). As the photosensitive resin film, a resin film containing a positive photosensitive resin was used. Here, pattern A is produced by passing a pattern with random luminance distribution through a plurality of Gaussian function-type bandpass filters with an aperture ratio of 45%, and the intensity Γ of the one-dimensional power spectrum at a spatial frequency of 0.002 μm ^-1 The ratio Γ(0.01)/Γ(0.002) of (0.002) to the intensity Γ(0.01) at the spatial frequency 0.01μm ^-1 is 4.8, and the intensity Γ(0.002) at the spatial frequency 0.002μm ^-1 to the spatial frequency 0.02μm ^- The ratio Γ(0.02)/ ^Γ ( ^{0.002) of the intensity Γ(0.02) at 1 is} 0.4. The ratio Γ(0.04)/Γ(0.002) was 5.5.

Then, the 1st etching process was performed using copper chloride solution. The etching amount at this time was set to 5 μm. The photosensitive resin film was removed from the roller after the 1st etching process, and the 2nd etching process was performed again using copper chloride solution. The etching amount at this time was set to 12 μm. Then, chrome plating was performed. At this time, the thickness of the chrome plating was set to 6 μm. The chrome-plated roller was buff-polished under the following conditions to prepare a mold A.

Abrasive: Micropolish (alumina abrasive with a particle size of 0.05 μm) (manufactured by Musashino Electronic Co., Ltd.)

Polishing cloth: Cross (Red) (manufactured by Musashino Electronic Co., Ltd.)

Roll speed: 60rpm

Pressing pressure: 1.1kPa

(Production of anti-glare film)

The following components were dissolved in ethyl acetate at a solid content concentration of 60%, and an ultraviolet curable resin composition A capable of forming a film showing a refractive index of 1.53 after curing was prepared.

Pentaerythritol triacrylate 60 parts

Multifunctional urethanized acrylate 40 parts

(reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate)

Diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide 5 parts

This ultraviolet curable resin composition A was coated on a triacetate cellulose (TAC) film with a thickness of 60 μm so that the thickness of the dried coating layer was 5 μm, and dried in a dryer set at 60° C. 3 minutes. The dried film was pressed against the molding surface (surface having surface irregularities) of the above-obtained mold A with a rubber roller so that the dried coating layer was on the mold side, and brought into close contact. In this state, light from a high-pressure mercury lamp with an intensity of 20 mW/cm ² is irradiated from the TAC film side, and the light is 200 mJ/cm ² in terms of h-ray conversion light quantity, and the coating layer is cured, thereby manufacturing the anti-glare membrane. Then, the obtained anti-glare film was peeled from the mold, and the transparent anti-glare film A provided with the anti-glare layer on the TAC film was produced.

<Example 2>

Mold B was fabricated in the same manner as Mold A in Example 1, except that the pattern formed by repeating the pattern B shown in FIG. , except that, it carried out similarly to Example 1, and produced the antiglare film. This antiglare film was referred to as antiglare film B. Here, pattern B is made by passing a pattern with random luminance distribution through a plurality of Gaussian function ^- type bandpass filters, the aperture ratio is 40%, and the intensity Γ( The ratio Γ(0.01)/Γ(0.002) of Γ(0.01)/Γ(0.002) to the intensity Γ(0.01) at the spatial frequency 0.01μm ^-1 is 3.7, and the intensity Γ(0.002) at the spatial frequency 0.002μm ^-1 is compared to the intensity Γ(0.01) at the spatial frequency 0.02μm ^-1 The ratio of the intensity Γ(0.02) at Γ(0.02)/Γ(0.002) is 0.3, the ratio of the intensity Γ(0.002) at the spatial frequency 0.002μm- ¹ to the intensity Γ(0.04) at the spatial frequency 0.04μm ^-1 Γ(0.04)/Γ(0.002) was 4.6.

<Example 3>

Mold C was produced in the same manner as that of Mold A in Example 1, except that a pattern formed by repeatedly arranging the pattern C shown in FIG. , except that, it carried out similarly to Example 1, and produced the antiglare film. Let this antiglare film be antiglare film C. Here, pattern C is made by passing a pattern with random luminance distribution through a plurality of Gaussian function-type bandpass filters with an aperture ratio of 45%, and the intensity Γ of the one-dimensional power spectrum at a spatial frequency of 0.002 μm ^-1 The ratio Γ(0.01)/Γ(0.002) of (0.002) to the intensity Γ(0.01) at the spatial frequency 0.01μm ^-1 is 3.5, and the intensity Γ(0.002) at the spatial frequency 0.002μm ^{- 1} is compared to the spatial frequency 0.02μm- The ratio Γ(0.02)/ ^Γ ( ^{0.002) of the intensity Γ(0.02) at 1 is} 0.42. The ratio Γ(0.04)/Γ(0.002) was 5.5.

<Comparative example 1>

Except for exposing the pattern formed by repeating the pattern D shown in FIG. D, except that, it carried out similarly to Example 1, and produced the antiglare film. This anti-glare film was referred to as anti-glare film D. Here, the pattern D is made by passing a pattern with random luminance distribution through a plurality of Gaussian function type band-pass filters with an aperture ratio of 35%, and the intensity Γ of the one-dimensional power spectrum at a spatial frequency of 0.002 μm ^-1 The ratio Γ(0.01)/Γ(0.002) of (0.002) to the intensity Γ(0.01) at the spatial frequency 0.01μm ^-1 is 4.8, and the intensity Γ(0.002) at the spatial frequency 0.002μm ^-1 to the spatial frequency 0.02μm ^- The ratio Γ(0.02)/ ^Γ ( ^{0.002) of the intensity Γ(0.02) at 1 is} 0.5. The ratio Γ(0.04)/Γ(0.002) was 6.9.

<Comparative example 2>

The production of the mold A of Example 1 was similar to that of Example 1, except that the pattern E shown in FIG. A mold E was produced in the same manner, and an anti-glare film was produced in the same manner as in Example 1 except that the mold A was replaced with the mold E. This anti-glare film was referred to as anti-glare film E. Here, the pattern E is made by passing a pattern with random brightness distribution through a plurality of Gaussian function-type bandpass filters with an aperture ratio of 45.0%, and the intensity Γ of the one-dimensional power spectrum at the spatial frequency of 0.002 μm ^-1 The ratio Γ(0.01)/Γ(0.002) of (0.002) to the intensity Γ(0.01) at the spatial frequency 0.01μm ^-1 is 4.2, and the intensity Γ(0.002) at the spatial frequency 0.002μm ^-1 to the spatial frequency 0.02μm ^- The ratio Γ(0.02)/Γ(0.002) of the intensity Γ(0.02) at ¹ is 14, the ratio of the intensity Γ(0.002) at the spatial frequency 0.002μm- ¹ to the intensity Γ(0.04) at the spatial frequency 0.04μm ^-1 The ratio Γ(0.04)/Γ(0.002) was 208.

<Comparative example 3>

Mirror-polish the surface of an aluminum roller (JIS-based A5056) with a diameter of 300 mm, and use a sand blasting device (manufactured by Fuji Seisakusho) to blast the polished aluminum surface with a blast pressure of 0.1 MPa (gauge pressure, the same below). ), the amount of beads used is 8 g/cm ² (the amount used for the unit surface area of the roller is 1 cm ² , the same below), sandblasted zirconia beads TZ-SX-17 (manufactured by Tosoh Co., Ltd., average particle size: 20 μm), aluminum Convexities and convexities were given to the surface of the roll. The obtained aluminum roll with unevenness was subjected to electroless nickel plating to prepare a die F. At this time, the thickness of the electroless nickel plating was set to 15 μm. Except having replaced mold A with mold F, it carried out similarly to Example 1, and produced the antiglare film. Let this antiglare film be antiglare film F.

<Comparative example 4>

The surface of the aluminum roll (A5056 based on JIS) with a diameter of 200 mm was prepared by repeating copper plating. Repeated copper plating consists of copper plating/thin silver plating/surface copper plating, and the overall thickness of the plating is about 200 μm. Mirror-polish the copper-plated surface, and then use a sandblasting device (manufactured by Fuji Manufacturing Co., Ltd.) to spray the abrasive surface with a sandblasting pressure of 0.05MPa (gauge pressure, the same below) and a bead consumption of 6g/ ^cm2 . Sand zirconia beads "TZ-SX-17" (manufactured by Tosoh Co., Ltd., average particle diameter: 20 μm) provided unevenness to the surface of the aluminum roll. The obtained copper-plated aluminum roll with unevenness was subjected to chrome plating, and a mold G was produced. At this time, the thickness of the chrome plating was set to 6 μm. Except having replaced mold A with mold G, it carried out similarly to Example 1, and produced the anti-glare film. Let this antiglare film be antiglare film G.

[Evaluation results]

Table 1 shows the evaluation results of the antiglare films obtained in the above Examples and Comparative Examples.

[Table 1]

The anti-glare films A to C (Examples 1 to 3) satisfying the requirements of the present invention have low haze, but have excellent anti-glare properties regardless of the frontal or oblique viewing angles, and suppress whitening and glare The effect is enough, too. On the other hand, whitening occurred in the antiglare film D (comparative example 1). The anti-glare film E (comparative example 2) had insufficient anti-glare property when viewed obliquely. The anti-glare film F (Comparative Example 3) easily generated glare. Antiglare film G (Comparative Example 4) had insufficient antiglare property when viewed obliquely.

Industrial applicability

The antiglare film of the present invention is suitable for image display devices such as liquid crystal displays.

Claims (2)

1. An antiglare film comprising a transparent support and an antiglare layer formed on the transparent support with fine surface irregularities, wherein, The anti-glare film has a total haze of 0.1% to 3% and a surface haze of 0.1% to 2%, The kurtosis Rku of the roughness curve of the surface uneven shape is 4.9 or less, The power spectrum of the complex amplitude obtained by the following power spectrum calculation method satisfies all the conditions of the following (1) to (3): (1) The ratio H(0.01)/H(0.002) of the intensity H(0.002) of the power spectrum at a spatial frequency of 0.002 μm ^-1 to the intensity H(0.01) of the power spectrum at a spatial frequency of 0.01 μm ^-1 is 0.02 or more And below 0.6; (2) The ratio H(0.02)/H(0.002) of the intensity H(0.002) of the power spectrum at a spatial frequency of 0.002 μm ^-1 to the intensity H(0.02) of the power spectrum at a spatial frequency of 0.02 μm ^-1 is 0.005 or more and less than 0.05; and (3) The ratio H(0.04)/H(0.002) of the intensity H(0.002) of the power spectrum at a spatial frequency of 0.002 μm ^-1 to the intensity H(0.04) of the power spectrum at a spatial frequency of 0.04 μm ^-1 is 0.0005 or more and less than 0.01, The power spectrum calculation method includes: (A) determine as the average plane of imaginary plane by the average elevation of described surface concavo-convex shape; (B) Determine the lowest elevation surface as an imaginary plane including the lowest elevation point of the surface uneven shape and parallel to the average plane, and the highest elevation point including the surface uneven shape and parallel to the average surface Parallel to the highest elevation plane as an imaginary plane; (C) For a plane wave with a wavelength of 550nm that is incident from the principal normal direction perpendicular to the lowest elevation surface and emerges from the highest elevation surface, calculate the highest Calculate the complex amplitude of the elevation surface, and obtain the power spectrum of the complex amplitude at this time. 2. The antiglare film according to claim 1, wherein, The sum Tc of transmission clarity measured by using five kinds of optical combs whose widths of dark and bright parts are 0.125mm, 0.25mm, 0.5mm, 1.0mm and 2.0mm is more than 375%. The sum Rc(45) of the reflection clarity measured at an incident angle of light of 45° using four kinds of optical combs with a width of 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm in the dark and bright parts is 180% or less, The sum Rc(60) of the reflection sharpness measured at an incident angle of light of 60° using four kinds of optical combs with dark and light widths of 0.25 mm, 0.5 mm, 1.0 mm, and 2.0 mm was 240% or less.