KR101598637B1 - Anti-glare film - Google Patents

Abstract

An antiglare film comprising a transparent support and an antiglare layer having a fine irregular surface formed thereon, the antiglare film comprising an energy spectrum H ₁ ^{2 at} a spatial frequency of 0.01 μm ^-1 at an elevation (height) of the fine irregular surface, ^-1 , the ratio H ₂ ² / H ₂ ² of the energy spectrum H ₂ ² is in the range of 3 to 15, the antiglare film exhibits excellent antiglare performance and is prevented from deterioration in visibility due to whitening , It is possible to provide an antiglare film which exhibits high contrast without occurrence of glare when placed on the surface of a high-definition image display device.

Description

ANTI-GLARE FILM

The present invention relates to an anti-glare film having low haze and excellent anti-glare properties.

An image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT) display, and an organic electroluminescence (EL) display is remarkably damaged in visibility when external light is projected on the display surface. In order to prevent the projection of the external light, in a television or a personal computer with an emphasis on picture quality, a video camera or a digital camera used in outdoor with a strong external light, a portable telephone which performs display using reflected light, A film layer for preventing the projection of external light is formed. This film layer is composed of a film on which an anti-reflection treatment is carried out by interference with an optical multilayer film and a film on which an antireflection treatment is performed to scatter incident light by making fine irregularities on the surface to blur the projected image. do. Among them, the former non-reflecting film needs to form a multi-layered film having a uniform optical film thickness, which increases the cost. On the other hand, the latter antiglare film can be produced at a relatively low cost, and thus is widely used for applications such as a large-sized personal computer and a monitor.

Such an antiglare film has heretofore been produced by, for example, a method of applying a resin solution in which fine particles are dispersed on a substrate sheet and adjusting the thickness of the coating film to expose the fine particles on the surface of the coating film to form random irregularities on the sheet have. However, the antiglare film produced by dispersing such fine particles has difficulty in obtaining the desired concavity and convexity because the arrangement and shape of the concavities and convexities depend on the dispersion state and the coating state of the fine particles in the resin solution, There is a problem that sufficient antiglare effect can not be obtained. Further, when such a conventional antiglare film is disposed on the surface of an image display device, there is a problem that so-called " whitening " is likely to occur in which the entire display surface becomes white due to scattered light, . It is also known that a so-called " flashing " phenomenon is likely to occur in which a pixel of an image display device and a surface irregularity shape of an antiglare film interfere with each other due to high definition of recent image display devices, There was also a problem. There is an attempt to diffuse light by providing a refractive index difference between the binder resin and the dispersed fine particles in order to solve the glare. However, when such an antiglare film is disposed on the surface of the image display device, There was also a problem that the contrast tends to decrease due to scattering.

On the other hand, there is also an attempt to develop the antifogging property only with fine irregularities formed on the surface of the transparent resin layer without containing fine particles. For example, Japanese Unexamined Patent Publication (Kokai) No. 2002-189106 (Patent Document 1) discloses a three-dimensional 10-point average roughness and a three-dimensional 10-point average roughness by curing the ionizing radiation curable resin with the ionizing radiation curable resin sandwiched between the embossing mold and the transparent resin film. And the average distance between the adjacent convex portions on the three-dimensional roughness reference plane is smaller than the predetermined value, and the ionizing radiation-curable resin layer on which the concavities and convexities are formed is provided on the transparent resin film Film is disclosed. However, even with the antiglare film disclosed in Patent Document 1, it has been difficult to achieve sufficient antiglare effect, inhibition of whitening, high contrast, and suppression of glare.

It is also possible to use not a diffusing film disposed on the display surface of a display device but a film in which fine irregularities are formed on the surface as the light diffusing layer disposed on the back side of the liquid crystal display device, as disclosed in Japanese Patent Application Laid- (Patent Document 2), Japanese Patent Application Laid-Open No. 2004-45471 (Patent Document 3), Japanese Patent Application Laid-Open No. 2004-45472 (Patent Document 4), and the like. Patent Documents 3 and 4 disclose a method of forming irregularities on the surface of a film by filling an emboss roll having a shape obtained by reversing the irregularities into an ionizing radiation curable resin liquid, The resin between the rolled plate and the transparent substrate is cured when the transparent substrate is in contact with the roll concave plate and the cured resin and the transparent substrate are brought into close contact with each other at the same time as the curing, And a transparent substrate is peeled from the roll concave plate.

However, in the methods disclosed in Patent Documents 3 and 4, since the composition of the ionic radiation curable resin liquid which can be used is limited and the leveling as in the case of diluting with a solvent and applying it can not be expected, It is expected to be. Further, in the methods disclosed in Patent Documents 3 and 4, it is necessary to directly fill the emboss roll concave plate with the resin liquid. Therefore, in order to ensure the uniformity of the concave and convex surface, the emboss roll concave plate requires high mechanical precision, There was a problem that it was difficult to produce emboss rolls.

Next, as a production method of a roll used for producing a film having concave and convex on its surface, for example, in Patent Document 2 described above, a cylindrical body is manufactured by using a metal or the like, and an electronic piece, A method of forming irregularities is disclosed. Japanese Patent Laid-Open Publication No. 2004-29240 (Patent Document 5) discloses a method for producing an embossing roll by a beads shot method. Japanese Patent Application Laid-Open No. 2004-90187 Document 6) discloses a method of producing an embossing roll through a step of forming a metal plating layer on the surface of the embossing roll, a step of mirror polishing the surface of the metal plating layer, and a step of peening if necessary .

However, in the state in which the surface of the embossing roll is subjected to the blast treatment as described above, the distribution of the irregularities due to the particle size distribution of the blast particles is generated, and it is difficult to control the depth of the recesses obtained by the blasting , There is a problem in obtaining a shape of irregularities excellent in anti-glare function with good reproducibility.

In addition, Patent Document 1 described above discloses that irregularities are formed by a sandblasting method or a beads shot method using a chromium-plated roller on the surface of iron. In addition, it is preferable to use chromium plating or the like for the purpose of improving the durability at the time of use on the mold surface on which the unevenness is formed, thereby making it possible to achieve hardening (hardening) and corrosion prevention There is indication of purpose. On the other hand, in each of the above-described Patent Documents 3 and 4, the iron core surface is chrome plated, subjected to a liquid sandblasting treatment of # 250 and then chrome-plated again to form fine irregularities on the surface .

However, in the embossing roll producing method, since the blasting or the shot is performed on the chrome plating having high hardness, it is difficult to form irregularities and it is difficult to precisely control the shape of the irregularities formed. Further, as described in Japanese Patent Application Laid-Open No. 2004-29672 (Patent Document 7), the chromium plating often has a rough surface depending on the material and the shape of the underlying material, There has been a problem in that it is difficult to design what kind of unevenness will occur because fine cracks generated by chromium plating are formed on the unevenness formed. Further, since there is a minute crack generated by chromium plating, the scattering characteristic of the finally obtained antiglare film changes in an undesirable direction. Further, since the surface of the finished roll varies in various colors depending on the combination of the material of the surface of the embossing roll base material and the plating type, in order to obtain the required surface relief shape with high precision, And an appropriate plating species must be selected. Further, even if a desired surface relief shape is obtained, durability at the time of use may be insufficient depending on the plating species.

Japanese Patent Application Laid-Open No. 2000-284106 (Patent Document 8) discloses that a substrate is subjected to sandblasting followed by an etching step and / or a lamination step of a thin film, but a metal plating layer is formed before the sandblasting step There is no description about the thing to do. Japanese Patent Laying-Open No. 2006-53371 (Patent Document 9) discloses polishing a base material, performing sandblasting, and then performing electroless nickel plating. Japanese Patent Application Laid-Open No. 2007-187952 (Patent Document 10) discloses a method in which a substrate is subjected to copper plating or nickel plating, followed by polishing, sandblasting, chrome plating to form an embossed plate Japanese Patent Laying-Open No. 2007-237541 (Patent Document 11) discloses a copper plating or a nickel plating, followed by polishing, sandblasting, etching, or copper plating, followed by chromium plating To produce an embossed plate. In the production method using these sand blasting processes, it is difficult to form the surface irregularities in a precisely controlled state, so that relatively large irregularities having a period of 50 mu m or more are also formed on the surface irregularities. As a result, there has been a problem that these large concavo-convex shapes interfere with the pixels of the image display device, resulting in a luminance distribution which is difficult to see, that is, so-called glare is likely to occur.

An object of the present invention is to provide an antiglare film which exhibits excellent antiglare performance while preventing deterioration of visibility due to whitening and exhibiting high contrast without causing glare when placed on the surface of a high definition image display device do.

The antiglare film of the present invention is an antiglare film formed by forming an antiglare layer having a fine uneven surface on a transparent support, wherein an energy spectrum H _{1 at} an elevation (altitude) at a spatial frequency of 0.01 탆 ^-1 of the fine uneven surface ² and the ratio H ₁ ² / H ₂ ² of the energy spectrum H ₂ ^{2 at} a spatial frequency of 0.04 μm ^-1 is in the range of 3 to 15.

In the antiglare film of the present invention, the energy spectrum H ₃ ^{2 at} the spatial frequency of 0.1 μm ^-1 at the height of the fine uneven surface and the ratio H ₃ ² / H ₃ of the energy spectrum H ₂ ^{2 at} the spatial frequency of 0.04 μm ^-1 , H ₂ ² is preferably 0.01 or less.

In the antiglare film of the present invention, it is preferable that the ratio of the surface with the inclined angle of the fine uneven surface of 5 or less is 95% or more.

In the antiglare film of the present invention, it is preferable that the antiglare layer does not contain fine particles of 0.4 탆 or more.

These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

1 is a perspective view schematically showing the surface of an antiglare film of the present invention.
Fig. 2 is a schematic diagram showing a state in which a function h (x, y) representing an elevation (height) is obtained in a discrete manner.
Fig. 3 shows the elevation of the fine concavo-convex surface topography of the antiglare film of the present invention as a two-dimensional discrete function h (x, y).
Fig. 4 shows an energy spectrum H ² (f _x , f _y ) obtained by performing discrete Fourier transform on the two-dimensional function h (x, y) shown in Fig. 3 in white and black gradations.
Fig. 5 is a diagram showing a cross section of the energy spectrum H ² (f _x , f _y ) shown in Fig. 4 at f _x = 0.
6 is a schematic diagram for explaining a method of measuring the tilt angle of the fine uneven surface.
7 is a graph showing an example of a bar graph of the inclination angle distribution of the fine uneven surface of the antiglare film.
8 is a diagram showing a part of image data, which is a pattern used for producing the antiglare film of the present invention, as a two-dimensional discrete function g (x, y) of gradation (gradation).
9 is a diagram showing an energy spectrum G ² (f _x , f _y ) obtained by performing discrete Fourier transform on the two-dimensional discrete function g (x, y) of the gradation shown in FIG. 8 by white and black gradations.
10 is a diagram showing a cross section at f _x = 0 of the energy spectrum G ² (f _x , f _y ) shown in Fig.
Fig. 11 is a diagram schematically showing a preferable example of the first half of the manufacturing method of a metal mold.
Fig. 12 is a diagram schematically showing a preferable example of the second half of the manufacturing method of the metal mold.
13 is a diagram schematically showing a state in which the side etching proceeds in the first etching step.
14 is a diagram schematically showing a state in which the uneven surface formed by the first etching step is dulled by the second etching step.
Fig. 15 is a diagram showing the gradation of image data obtained from the pattern used at the time of manufacturing the mold of Embodiment 2 by a two-dimensional function.
16 is a diagram showing the gradation of image data obtained from a pattern used in manufacturing a mold of Comparative Example 1 by a two-dimensional function.
17 is a diagram showing the gradation of image data obtained from the pattern used in the production of the mold of Comparative Example 2 by a two-dimensional function.
18 is a view showing a cross section of the energy spectrum obtained at the f _x = 0 obtained from the two-dimensional function of the elevation height of the micro concavo-convex surface shape of the antiglare films B to F. Fig.
19 is a view showing a cross-section according to the second embodiment and Comparative Example 1 and Comparative Example 2 f _x = 0 of the energy spectrum of the pattern used for.

<Antidrug film>

Hereinafter, preferred embodiments of the present invention will be described in detail.

An anti-glare film of the present invention, the transparent support on, will the formed antiglare layer having a fine uneven surface shape (fine uneven surface), the energy spectrum of the spatial frequency of 0.01 ㎛ ^-1 minute uneven surface elevations (標高) of H ^_12, a non-H _{1 ²} / H ^{2 2} ₂ H ² of the energy spectrum of the spatial frequency is 0.04 ㎛ ^-1 characterized in that the range of 3 to 15. Up to now, the period of the micro concavo-convex surface of the antiglare film is determined by the average length (RSm) of the roughness curve elements described in JIS B 0601, the average length (PSm) of the section curve elements and the average length (WSm) It was evaluated. However, in such a conventional evaluation method, it is not possible to accurately evaluate a plurality of cycles included in the fine uneven surface. Therefore, it is difficult to precisely evaluate the correlation between the glare and the micro concavo-convex surface and the correlation between the fluorescence and the micro concavo-convex surface, and it is difficult to produce an antiglare film having both suppression of glare and sufficient antiglare performance.

The inventors of the present invention have found that, in an antiglare film in which an antiglare layer having a fine uneven surface is formed on a transparent support, when the fine uneven surface exhibits a specific spatial frequency distribution, Respectively. That is, according to the present invention, the energy spectrum H ₁ ^{2 at} the spatial frequency of 0.01 μm ^-1 at the elevation of the fine uneven surface and the ratio H ₁ ² / H of the energy spectrum H ₂ ^{2 at} the spatial frequency of 0.04 μm ^-1 ₂ ² within a specific range, it is possible to prevent deterioration of visibility due to whitening, while exhibiting excellent antiglare performance, and to provide an antiglare film that exhibits high contrast without causing glare when placed on the surface of a high- / RTI &gt;

First, the energy spectrum of the elevation of the fine uneven surface of the antiglare film will be described. 1 is a perspective view schematically showing the surface of an antiglare film of the present invention. As shown in Fig. 1, the antiglare film 1 of the present invention has an antiglare layer in which fine irregularities 2 are formed on its surface. Here, the "elevation of the fine uneven surface" in the present invention means a virtual plane having the height at the lowest point of the fine uneven surface at an arbitrary point P on the surface of the film 1 0 占 퐉) of the film in the main normal direction 5 (normal direction in the virtual plane) of the film. As shown in Fig. 1, when the rectangular coordinates in the film plane are represented by (x, y), the elevation of the fine uneven surface can be represented by a two-dimensional function h (x, y) of coordinates (x, y). In Fig. 1, the entire surface of the film is indicated by the projection plane 3.

The elevation of the fine uneven surface can be obtained from the three-dimensional information of the surface shape measured by a confocal microscope, an interference microscope, an atomic force microscope (AFM), or the like. The horizontal resolution required for the measuring instrument is at least 5 μm or less, preferably 2 μm or less, and the vertical resolution is at least 0.1 μm or less, preferably 0.01 μm or less. Examples of the non-contact three-dimensional surface shape and roughness measuring instrument suitable for this measurement include a New View 5000 series (manufactured by Zygo Corporation, available from Zagyo Co., Ltd.) and a three-dimensional microscope PLμ2300 [manufactured by Sensofar Co., Ltd.]. The measurement area is preferably at least 200 탆 x 200 탆 or more, and more preferably 500 탆 x 500 탆 or more, since the resolution of the energy spectrum of the elevation is required to be 0.01 탆 ^-1 or less.

Next, a method of obtaining the elevation energy spectrum from the two-dimensional function h (x, y) will be described. First, a two-dimensional function H (f _x , f _y ) is obtained from the two-dimensional function h (x, y) by two-dimensional Fourier transform defined by equation (1).

Where f _x and f _y are frequencies in the x and y directions, respectively, and have a dimension of the reciprocal of the length. In the equation (1),? Is the circumferential ratio and i is the imaginary unit. The energy spectrum H ² (f _x , f _y ) can be obtained by squaring the obtained two-dimensional function H (f _x , f _y ). This energy spectrum H ² (f _x , f _y ) represents the spatial frequency distribution of the fine uneven surface of the antiglare film.

Hereinafter, a method of obtaining the energy spectrum of the fine uneven surface of the antiglare film will be described in more detail. Three-dimensional information of the surface shape actually measured by the confocal microscope, interference microscope, atomic force microscope and the like is generally obtained as a discrete value, that is, an elevation corresponding to a plurality of measurement points. Fig. 2 is a schematic diagram showing a state in which a function h (x, y) representing an altitude is discretely obtained. As shown in Fig. 2, the orthogonal coordinate in the film plane is represented by (x, y), a line divided on the film projection plane 3 in units of? X in the x-axis direction and a line divided in? In the actual measurement, the elevation of the surface of the fine irregularities is obtained as a discrete elevation value for each intersection of each dashed line on the film projection surface 3, represented by the broken line.

As shown in Fig. 2, when the measurement range in the x-axis direction is X = MΔx and the measurement range in the y-axis direction is Y = NΔy, the number of the obtained elevation values is determined by the measurement range and Δx and Δy. The number of elevation values obtained is (M + 1) x (N + 1).

(J DELTA x, k DELTA y) (where j is not less than 0 but not more than M, and k is not less than 0 but not more than N), the target point A on the film projection plane 3 corresponds to the target point A The elevation of the point P on the film plane can be expressed as h (jΔx, kΔy).

Here, the measurement intervals [Delta] x and [Delta] y depend on the horizontal resolution of the measuring instrument. In order to evaluate the surface of fine irregularities with precision, both of [Delta] x and [Delta] y are preferably 5 [micro] m or less and more preferably 2 [micro] m or less. Also, as described above, the measurement ranges X and Y are all preferably 200 mu m or more, more preferably 500 mu m or more.

Thus, in the actual measurement, the function representing the elevation of the fine uneven surface is obtained as a discrete function h (x, y) having (M + 1) x (N + 1) A discrete function h (x, y) and equation _{(2) (f x, f} y) that is obtained discrete function H (f _x, f _y) by a discrete Fourier transform, a discrete function H, defined as obtained by the measurement The discrete function H ² (f _x , f _y ) of the energy spectrum is found by squaring. 1 in the formula (2) is an integer equal to or greater than (M + 1) / 2 and equal to or less than (M + 1) / 2 and m is an integer equal to or greater than - (N + . Further,? F _x and? F _y are frequency intervals in the x direction and the y direction, respectively, and are defined by equations (3) and (4).

Fig. 3 shows the height of the fine uneven surface of the antiglare film of the present invention as a two-dimensional discrete function h (x, y). In FIG. 3, the elevation is represented by a white and black gradation. The discrete function h (x, y) shown in FIG. 3 has 512 × 512 values, and the horizontal resolutions Δx and Δy are 1.66 μm.

4 shows the energy spectrum H ² (f _x , f _y ) obtained by the discrete Fourier transform of the two-dimensional function h (x, y) shown in FIG. 3 as a white and black gradation. The energy spectrum H ² (f _x , f _y ) shown in FIG. 4 is also a discrete function having 512 × 512 values, and the horizontal resolutions Δf _x and Δf _y are 0.0012 μm ^-1 .

As shown in Fig. 3, the concave and convex portions of the micro concavity and convexity of the antiglare film of the present invention are randomly formed, so that the energy spectrum of Fig. 4 is symmetrical about the origin. Thus, the energy spectrum of the spatial frequency H ₁ ² 0.01 ㎛ ^-1, the zero point of the energy spectrum is a two-dimensional function, H ₂ ^{2 2} energy spectrum H (f _x, f _y) in the spatial frequency 0.04 ㎛ ^-1 And can be obtained from the cross section of the passage. Fig. 5 shows a cross section at _fx = 0 of the energy spectrum H ² (f _x , f _y ) shown in Fig. From this, the energy spectrum H ₁ ² at the spatial frequency of 0.01 μm ^-1 was 4.8, the energy spectrum H ₂ ² at the spatial frequency of 0.04 μm ^-1 was 0.35, and the ratio H ₁ ² / H ₂ ² was 14 .

As described above, in the antiglare film of the present invention, the energy spectrum H ₁ ^{2 at} the spatial frequency of 0.01 μm ^-1 at the height of the fine irregularities and the energy spectrum H ₂ ^{2 at} the spatial frequency of 0.04 μm ^-1 And the ratio H ₁ ² / H ₂ ² is 3 to 15. The reason why the ratio H ₁ ² / H ₂ ² of the energy spectrum is less than 3 is that the concavity and convexity of the long period of 100 mu m or more contained in the fine concavo-convex surface of the antiglare film is small, have. In such a case, the projection of the external light can not be effectively prevented, and sufficient anti-glare performance can not be obtained. On the other hand, the ratio H ₁ ² / H ₂ ² of the energy spectrum is higher than 15 in the case where the concavity and convexity of the long period of 100 μm or more contained in the surface of the fine irregularities is large, Respectively. In such a case, the antiglare film tends to cause glare when placed in a high-definition image display device. In addition, the short-period component of less than 10 占 퐉 included in the surface of the fine irregularities does not contribute effectively to the antifogging property and causes scattering of light incident on the fine irregular surface to cause whitening. Specifically, if the energy spectrum of the spatial frequency of 0.1 ㎛ ^-1 as H ₃ ^2, preferred ratio is 0.1 or less H _{3 ²} / H ^{2 2} of the energy spectrum, and more preferably 0.01 or less. In the energy spectrum shown in FIG. 5, the energy spectrum H ₃ ² at a spatial frequency of 0.1 μm ^-1 is 0.00076. From this, it can be seen that the ratio H ₃ ² / H ₂ ² is 0.0022.

The inventors of the present invention have further found that when the surface of micro concavity and convexity exhibits a specific inclined angle distribution in the antiglare film, the antiglare film exhibits excellent antiglare performance and is more effective in effectively preventing whitening. That is, in the antiglare film of the present invention, it is preferable that the ratio of the surface of the micro concavo-convex surface having the inclination angle of 5 or less is 95% or more. If the ratio of the surface with the inclined angle of the fine concavo-convex surface of 5 or less is less than 95%, the inclination angle of the concavo-convex surface is urged and the light from the circumference is condensed to cause whitening in which the display surface becomes wholly white . In order to suppress such a light condensing effect and prevent whitening, the higher the ratio of the surface having the inclined angle of the fine irregularities of 5 DEG or less, the better the higher the ratio is, preferably 97% or more, and more preferably 99% or more.

Here, the "angle of inclination of the fine concavo-convex surface" in the present invention refers to the angle of inclination of the surface of the antiglare film 1 at an arbitrary point P on the surface of the antiglare film 1 shown in FIG. 1, And the angle (ψ) formed by the local normal line (6) with respect to the normal line (6). Similar to the elevation, the inclination angle of the fine uneven surface can be obtained from the three-dimensional information of the surface shape measured by a confocal microscope, an interference microscope, and an atomic force microscope (AFM).

Here, FIG. 6 is a schematic diagram for explaining a method of measuring the tilt angle of the fine uneven surface. As shown in FIG. 6, a point of interest A on a virtual plane FGHI indicated by a dotted line is determined, and a point A on the point A is determined in the vicinity of the point A on the x- Points C and E are taken symmetrically with respect to the point A in the vicinity of the point A and the point A on the y-axis passing through the point A and in the vicinity of the point A on the y-axis and the points C and E corresponding to these points B, C, D and E The points Q, R, S and T on the film surface are determined. In Fig. 6, the orthogonal coordinates in the film plane are represented by (x, y), and the coordinates in the film thickness direction are represented by z. The plane FGHI is defined by a straight line parallel to the x axis passing through point C on the y axis and a straight line parallel to the x axis passing through point E on the y axis and parallel to the y axis passing through point B on the x axis, G, H, and I of a straight line parallel to the y-axis passing through the point D on the x-axis. 6, the position of the actual film surface is drawn to the upper side with respect to the plane FGHI, but depending on the position taken by the point of interest A, the actual position of the film surface may come above the plane FGHI , It may come down.

The inclination angles of the obtained surface shape data are set such that points P on the actual film surface corresponding to the target point A and points Q on the actual film surface corresponding to the four points B, C, D, An average normal vector obtained by averaging the normal vectors 6a, 6b, 6c and 6d of the polygon 4 planes extended by the total of five points of R, S, and T, that is, the four triangles PQR, PRS, PST, 6). After determining the tilt angle for each measurement point, a bar graph is calculated.

7 is a graph showing an example of a bar graph of the inclination angle distribution of the fine uneven surface of the antiglare film. In the graph shown in Fig. 7, the horizontal axis is an inclined angle, and is divided into 0.5 degree pitches. For example, the leftmost vertical bar indicates the distribution of the set in which the inclination angle is in the range of 0 DEG to 0.5 DEG, and the angle increases by 0.5 DEG in the rightward direction. In the figure, the lower limit value of the value is indicated for each of two graduations of the horizontal axis. For example, the portion indicated by "1" on the horizontal axis represents the distribution of the set whose inclination angle is in the range of 1 ° to 1.5 °. The vertical axis represents the distribution of the inclination angle, and is a value that becomes 1 when the total is inclined. In this example, the ratio of the face having the inclination angle of 5 DEG or less is approximately 100%.

It is also preferable that the antiglare film of the present invention does not contain fine particles of 0.4 mu m or more in the antiglare layer from the viewpoint of effectively exhibiting high contrast when placed on the surface of the image display device. The conventional antiglare film is produced by applying a resin solution in which fine particles are dispersed on a base sheet and adjusting the thickness of the coating film to expose the fine particles on the surface of the coating film to thereby form random irregularities on the sheet. In order to eliminate glare, an antiglare film produced by dispersing such fine particles often has scattering of light by providing a refractive index difference between the binder resin and the fine particles. When such an antiglare film is disposed on the surface of an image display device, contrast is lowered due to light scattering at the interface between the fine particles and the binder resin. In the antiglare film of the present invention, since the frequency distribution of the fine uneven surface is appropriately designed, there is no need to scatter light and eliminate glare. Therefore, it is preferable not to include fine particles of 0.4 mu m or more which cause a decrease in contrast.

&Lt; Method of producing antiglare film >

The antiglare film of the present invention is preferably produced using a pattern in which the energy spectrum does not have a maximum value in the range of 0 占 퐉 ^{-1 to} 0.04 占 퐉 ^-1 or less in order to precisely form the fine uneven surface having the frequency distribution . Here, the &quot; pattern &quot; means image data for forming the fine concavo-convex surface of the antiglare film of the present invention, a mask having a transparent portion and a shielding portion, and the like.

The energy spectrum of the pattern is, for example, image data, the image data is converted into a gray scale of 256 gradations, the gradation of the image data is represented by a two-dimensional function g (x, y) (F _x , f _y ) by Fourier transform to obtain a two-dimensional function G (f _x , f _y ) and squaring the obtained two-dimensional function G (f _x , f _y ). In addition, when a mask having transparent portions and light blocking portions, indicates the transmittance in a two-dimensional function t (x, y), by a two-dimensional function t (x, y) obtained Fourier transform calculates a two-dimensional function T (f _x, f _y) , And the obtained two-dimensional function T (f _x , f _y ) is squared. Here, x and y represent orthogonal coordinates in the image data plane or in the mask plane, and f _x and f _y represent the frequency in the x direction and the frequency in the y direction.

The two-dimensional function g (x, y) of the gradation and the two-dimensional function t (x, y) of the transmittance are obtained as a discrete function even when the energy spectrum of the pattern is obtained as in the case of obtaining the energy spectrum of the surface of the fine uneven surface. The case is common. In this case, the energy spectrum can be calculated by discrete Fourier transform similarly to the case of obtaining the energy spectrum of the elevation of the fine uneven surface.

8 is a diagram showing a part of image data which is a pattern used for producing the antiglare film of the present invention (a pattern used in the production of a mold of Example 1 described later) by a two-dimensional discrete function g (x, y) . The two-dimensional discrete function g (x, y) shown in FIG. 8 has 512 × 512 values, and the horizontal resolutions Δx and Δy are 2 μm. The image data, which is a pattern shown in Fig. 8, has a size of 2 mm x 2 mm and is created at 12800 dpi.

9 is a diagram showing an energy spectrum G ² (f _x , f _y ) obtained by performing discrete Fourier transform on the two-dimensional discrete function g (x, y) of the gradation shown in FIG. 8 by white and black gradations. The discrete functions G ² (f _x , f _y ) shown in FIG. 8 also have 512 × 512 values, and the horizontal resolutions Δf _x and Δf _y are 0.0010 μm ^-1 . As shown in Fig. 8, since the pattern prepared for producing the antiglare film of the present invention is random, the energy spectrum of Fig. 9 is symmetrical about the origin. Therefore, the maximum value of the energy spectrum of the pattern can be obtained from the cross section passing through the origin of the energy spectrum. 10 is a diagram showing a cross section at f _x = 0 of the energy spectrum G ² (f _x , f _y ) shown in Fig. It from the pattern shown in Figure 8 has the maximum value in the spatial frequency 0.045 ㎛ ^-1, 0 ㎛ ^-1 exceeds 0.04 ㎛ ^-1 or less and it can be seen that it does not have the maximum value.

When the energy spectrum of the pattern for producing the antiglare film has a maximum value in the range of 0 占 퐉 ^{-1 to} 0.04 占 퐉 ^-1 or less, the frequency distribution of the fine uneven surface of the resulting antiglare film does not satisfy the requirements of the present invention So that it can not combine glare and sufficient repellency.

In order to prepare a pattern having a maximum value in an energy spectrum exceeding 0 占 퐉 ^{-1 and} 0.04 占 퐉 ^-1 or less, a dot diameter of less than 20 占 퐉 may be randomly and uniformly arranged. The dot diameters to be randomly arranged may be one type or a plurality of types.

The antiglare film having a fine uneven surface using the above-described pattern can be produced by a printing method, a pattern exposure method, an embossing method, or the like. For example, in the printing method, the above-mentioned pattern is printed and formed on a transparent support by flexographic printing, screen printing, inkjet printing or the like using a photo-curing resin or a thermosetting resin, followed by drying, And then curing it, the antiglare film of the present invention can be produced.

For example, in flexo printing, a flexo plate, which is a relief plate based on the above-described pattern, is manufactured, a photocurable resin is applied to the convex portion of the flexo plate, the applied photo-curing resin is transferred onto a transparent support, The fine unevenness based on the above-described pattern can be formed on the transparent support. In the case of screen printing, a screen, which is a hole plate based on the above-described pattern, is prepared, the above-described pattern is printed on a transparent support using the screen and a photo-curable resin, and then the photo- Fine irregularities can be formed on the transparent support. In the case of inkjet printing, the above-mentioned pattern is printed directly on the transparent support using a photo-curable resin, and then the photo-curable resin is cured by an actinic ray to form fine irregularities on the transparent support. Since fine irregularities formed by such a printing method generally have a tilted angle and there is a portion where the resin layer is not formed on the transparent support, a photocurable resin is further coated on the fine unevenness formed by the printing method , It is preferable to smooth the inclination angle and to form the resin layer on the entire surface of the transparent support.

In the pattern exposure method, after a photocurable resin is applied on a transparent support, pattern exposure is carried out by direct drawing exposure using a laser using the above-described pattern or by front exposure through a mask having the above-described pattern, After development, the antiglare film of the present invention can be produced by curing by actinic ray or heat. In the direct imaging exposure by laser, after the photocurable resin is applied on the transparent support, the above-described pattern is directly drawn and exposed by the laser light, and the exposed portion is left or dissolved by the development, and the remaining photocurable By irradiating the resin with an actinic ray to completely cure it, it is possible to form fine irregularities based on the pattern described above on the transparent support. Since micro-irregularities formed by such a direct drawing exposure by a laser generally have a tilting angle, it is preferable to further coat the photo-curing resin on fine irregularities formed by laser direct exposure and to smooth the tilting angle desirable. In the case of the entire exposure through the mask, a mask having the above-mentioned pattern is manufactured, a photocurable resin is coated on the transparent support, the photocurable resin is exposed through the mask, Or by dissolving the photo-curable resin, and irradiating the remaining photo-curing resin with an actinic ray to completely cure it, whereby the fine unevenness based on the above-described pattern can be formed on the transparent support. In the front exposure through the mask, the inclination angle of the fine unevenness can be controlled by appropriately controlling the proximity gap or by controlling the degree of exposure by manufacturing the mask with the gray-scale mask.

In the embossing method, a mold having a fine uneven surface is produced by using the above-described pattern, the uneven surface of the produced mold is transferred onto a transparent support, and then the transparent support onto which the uneven surface is transferred is peeled off from the mold, The antiglare film of the invention can be produced. Herein, the antiglare film of the present invention is preferably produced by the emboss method from the viewpoint of producing fine concavo-convex surfaces with high precision and reproducibility.

Examples of the embossing method include a UV embossing method using a photocurable resin and a hot embossing method using a thermoplastic resin. Among them, the UV embossing method is preferable from the viewpoint of productivity.

The UV embossing method is a method in which a photo-curable resin layer is formed on the surface of a transparent support, and the photo-curable resin layer is cured on the concavoconvex surface of the mold while curing it, thereby transferring the uneven surface of the mold to the photo-curable resin layer. Specifically, an ultraviolet curable resin is coated on a transparent support, and the ultraviolet curable resin is cured by irradiating ultraviolet rays from the transparent support side in a state in which the coated ultraviolet curable resin is in close contact with the uneven surface of the mold, The transparent support on which the ultraviolet curable resin layer after curing is formed is peeled off, and the shape of the mold is transferred to the ultraviolet curable resin.

When the UV embossing method is used, the transparent support may be a substantially optically transparent film. For example, a triacetylcellulose film, a polyethylene terephthalate film, a polymethylmethacrylate film, a polycarbonate film, or a norbornene compound may be used as a monomer And a resin film such as a solvent cast film or an extruded film of a thermoplastic resin such as amorphous cyclic polyolefin.

The type of ultraviolet-curing resin used when the UV embossing method is used is not particularly limited, but commercially available ones can be used. It is also possible to use a resin that can be cured in visible light having a longer wavelength than ultraviolet light by combining a photoinitiator appropriately selected for the ultraviolet curable resin. Specifically, polyfunctional acrylates such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate may be used alone or as a mixture of two or more of them. ), Irgacure 184 (manufactured by Ciba Specialty Chemicals Inc.), and lucylline TPO (manufactured by BASF) can be suitably used.

On the other hand, the hot emboss method is a method in which a transparent support formed of a thermoplastic resin is pressed against a mold in a heated state, and the surface shape of the mold is transferred to a transparent support. As the transparent support for use in the hot embossing method, any transparent support may be used as long as it is substantially transparent, and examples thereof include polymethyl methacrylate, polycarbonate, polyethylene terephthalate, triacetyl cellulose, amorphous cyclic polyolefin having a norbornene- Of a thermoplastic resin can be used. These transparent resin films can also be suitably used as a transparent support for coating the ultraviolet curable resin in the above-described UV embossing method.

&Lt; Method for producing a mold for manufacturing an antiglare film &

Hereinafter, a method for producing a mold used for producing the antiglare film of the present invention will be described. The method for producing the mold used in the production of the antiglare film of the present invention is not particularly limited as long as the method can obtain a predetermined surface shape using the above-described pattern. However, in order to produce fine concave- and convex surfaces with high precision and reproducibility, [1] a first plating step, [2] a polishing step, [3] a photosensitive resin film coating step, [4] an exposure step, [5] a developing step, [6] a first etching step, 7] photosensitive resin film peeling step, and [8] second plating step. Fig. 11 is a diagram schematically showing a preferable example of the first half of the manufacturing method of a metal mold. Fig. 11 schematically shows a cross section of a mold in each step. With reference to FIG. 11, each step of the manufacturing method of the present invention will be described in detail.

[1] First plating process

In the manufacturing method of the present mold, copper plating or nickel plating is first performed on the surface of the substrate used for the mold. As described above, by performing copper plating or nickel plating on the surface of the mold base material, the adhesion and gloss of the chromium plating in the subsequent second plating step can be improved. That is, as described in the background art, when chromium plating is performed on the surface of iron or the like, or chromium plating is performed again after the irregularities are formed on the chromium-plated surface by the sandblasting method, the beads shot method, or the like, So that fine cracks are generated and it becomes difficult to control the concavo-convex shape of the mold surface. On the other hand, by first subjecting the substrate surface to copper plating or nickel plating, such a problem can be eliminated. This is because copper plating or nickel plating has a high covering property and a strong smoothing action, so that it forms a flat and glossy surface by filling small irregularities and cavities of the substrate for a mold. Even if chrome plating is performed in the second plating process described later due to the characteristics of copper plating or nickel plating, the roughness of the chromium plating surface, which is thought to be caused by minute unevenness and cavities existing in the substrate, And the occurrence of fine cracks is reduced due to high coating properties of copper plating or nickel plating.

The copper or nickel used in the first plating process may be pure metal or may be an alloy mainly composed of copper or an alloy mainly composed of nickel. Thus, the term &quot; copper &quot; And copper alloy, and &quot; nickel &quot; is meant to include nickel and nickel alloys. Copper plating and nickel plating may be performed by electrolytic plating or electroless plating, respectively, but electrolytic plating is usually employed.

When copper plating or nickel plating is carried out, if the plating layer is too thin, the influence of the surface of the base can not be excluded. Therefore, the thickness is preferably 50 m or more. The upper limit of the thickness of the plating layer is not critical, but from the viewpoint of cost and the like, a range of about 500 탆 is generally sufficient.

In addition, in the method for producing the metal mold, aluminum, iron and the like can be mentioned as metal materials suitably used for forming the base material from the viewpoint of cost. For convenience of handling, lightweight aluminum is more preferable. The aluminum or the railway referred to herein may be a pure metal or an alloy mainly composed of aluminum or iron.

The shape of the base material is not particularly limited as long as it is a suitable shape conventionally employed in the art, and may be a flat plate shape, or a cylindrical or cylindrical shape roll. When a mold is produced using a roll-shaped substrate, there is an advantage that an antiglare film can be produced in a continuous roll shape.

[2] Polishing process

In the subsequent polishing step, the substrate surface subjected to copper plating or nickel plating is polished in the above-described first plating step. In the production method of the present mold, it is preferable to polish the surface of the base material in a state close to the mirror surface through this step. This is because the metal plate or the metal roll serving as the substrate often has been subjected to machining such as cutting or grinding in order to obtain a desired precision. As a result, a trace of machining remains on the surface of the substrate, and copper plating or nickel plating is performed , These processing marks may remain, and the surface may not be completely smoothed in the plated state. In other words, even if a step to be described later is carried out on the surface where such deep processing marks are left, there is a possibility that the irregularities such as machining marks are deeper than the irregularities formed after the respective steps are performed, , And when an antiglare film is produced using such a mold, the optical characteristics may have an unexpected influence. Fig. 11 (a) shows a case where the substrate 7 for the plate-shaped mold is subjected to copper plating or nickel plating on its surface in the first plating step (the copper plating or nickel plating layer formed in the step (Not shown), and also has a mirror-polished surface 8 by a polishing process.

The method of polishing the substrate surface subjected to copper plating or nickel plating is not particularly limited, and any of mechanical polishing, electrolytic polishing, and chemical polishing may be used. Examples of mechanical polishing include super finishing, lapping, fluid polishing, and buff polishing. The surface roughness after polishing preferably has a centerline average roughness (Ra) in accordance with JIS B 0601 of 0.1 탆 or less, more preferably 0.05 탆 or less. If the center line average roughness (Ra) after polishing is larger than 0.1 占 퐉, there is a possibility that the final roughness of the mold surface may remain affected by the surface roughness after polishing. The lower limit of the center line average roughness (Ra) is not particularly limited, and there is no need to specify the lower limit of the center line average roughness Ra because there are naturally limitations in terms of processing time and processing cost.

[3] Photosensitive resin film application step

In the subsequent photosensitive resin film application step, a photosensitive resin film is formed by applying a solution in which a photosensitive resin is dissolved in a solvent on the surface 8 of the base material 7 subjected to the mirror polishing by the above-mentioned polishing step, and heating and drying . Fig. 11 (b) schematically shows a state in which the photosensitive resin film 9 is formed on the surface 8 of the base material 7. Fig.

As the photosensitive resin, conventionally known photosensitive resins can be used. For example, as a negative-type photosensitive resin having a property of curing a photosensitive portion, a monomer or prepolymer of an acrylic ester having an acrylic group or a methacrylic group in the molecule, a mixture of a bisazide and a diene rubber, a polyvinyl cinnamate-based compound, . As the positive photosensitive resin having the property that the photosensitive portion is eluted by development and only the non-photosensitive portion remains, a phenol resin-based nano-bloc resin-based resin or the like can be used. If necessary, various additives such as a sensitizer, a development promoter, an adhesion modifier, and a coating improver may be added to the photosensitive resin.

When these photosensitive resins are applied to the surface 8 of the base material 7, it is preferable to apply them in an appropriate solvent in order to form a good coating film, and it is preferable to apply the photosensitive resin in a solvent such as cellosolve solvent, propylene glycol solvent, Alcohol-based solvents, ketone-based solvents, and highly polar solvents.

As a method of applying the photosensitive resin solution, known methods such as meniscus coat, fountain coat, dip coat, spin coating, roll coating, wire bar coating, air knife coating, blade coating and curtain coating can be used . The thickness of the coating film is preferably in the range of 1 탆 to 6 탆 after drying.

[4] Exposure step

In the subsequent exposure step, a pattern having no maximum value in the energy spectrum exceeding 0 占 퐉 ^{-1 and} 0.04 占 퐉 ^-1 or less is exposed on the photosensitive resin film 9 formed in the above photosensitive resin film coating step. The light source used in the exposure process may be appropriately selected in accordance with the photosensitive wavelength and sensitivity of the applied photosensitive resin. For example, a g line (wavelength: 436 nm) of a high-pressure mercury lamp, an h line (wavelength: 405 nm) A semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm), a YAG laser (wavelength: 1064 nm), a KrF excimer laser (wavelength: 248 nm), ArF An excimer laser (wavelength: 193 nm), and an F2 excimer laser (wavelength: 157 nm).

In order to precisely form the surface relief shape in the manufacturing method of the present mold, it is preferable to expose the above-described pattern on the photosensitive resin film in a precisely controlled state in the exposure step. In the mold manufacturing method of the present invention, in order to expose the above-described pattern on the photosensitive resin film with high precision, a pattern on the computer is formed as image data, and a pattern based on the image data is formed on a computer- It is preferable to image by laser light. A laser drawing apparatus for forming a printing plate can be used for laser drawing. As such a laser beam drawing apparatus, for example, a Laser Stream FX (manufactured by Sankyu Laboratory Co., Ltd.) and the like can be mentioned.

Fig. 11 (c) schematically shows a state in which the pattern is exposed on the photosensitive resin film 9. Fig. When the photosensitive resin film is formed of a negative type photosensitive resin, the exposure of the exposed region 10 causes the crosslinking reaction of the resin to proceed by exposure, and the solubility in a developing solution described later is lowered. Therefore, in the developing step, the unexposed area 11 is dissolved by the developing solution, and only the exposed area 10 remains on the surface of the substrate to become a mask. On the other hand, in the case where the photosensitive resin film is formed of a positive photosensitive resin, the exposure of the exposed region 10 causes the bond of the resin to be broken by exposure to increase the solubility in a developing solution described later. Therefore, in the developing step, the exposed region 10 is dissolved by the developing solution, and only the unexposed region 11 remains on the substrate surface to become a mask.

[5] Development process

In the subsequent developing step, when a negative photosensitive resin is used for the photosensitive resin film 9, the unexposed area 11 is dissolved by the developing solution, and only the exposed area 10 remains on the mold base material , And serves as a mask in the subsequent first etching step. On the other hand, in the case where a positive photosensitive resin is used for the photosensitive resin film 9, only the exposed region 10 is dissolved by the developing solution, the unexposed region 11 remains on the substrate for a mold, 1 &lt; / RTI &gt; etching process.

Conventionally known developers may be used for the developer used in the development process. Examples thereof include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate and ammonia water, primary amines such as ethylamine and n-propylamine, and organic bases such as diethylamine and di- 2 amines, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide , And cyclic amines such as pyrrole and piperidine; organic solvents such as xylene and toluene; and the like.

The developing method in the developing step is not particularly limited, and examples of such methods include immersion, spray, brush, and ultrasonic.

Fig. 11 (d) schematically shows a state in which the photosensitive resin film 9 is subjected to development processing using a negative-type photosensitive resin. In Fig. 11C, the unexposed area 11 is dissolved by the developing solution, and only the exposed area 10 remains on the surface of the substrate to become the mask 12. Fig. Fig. 11 (e) schematically shows a state in which the photosensitive resin film 9 is subjected to development processing using a positive photosensitive resin. In Fig. 11 (c), the exposed region 10 is dissolved by the developing solution, and only the unexposed region 11 remains on the substrate surface to become the mask 12.

[6] First etching step

In the subsequent first etching step, the base material for a mold at a portion where there is no mask is mainly etched by using the photosensitive resin film remaining on the surface of the base material for the mold after the above-described development step as a mask. 12 is a diagram schematically showing a preferable example of the second half of the manufacturing method of the present mold. Fig. 12 (a) schematically shows a state in which the mold base material 7 of the portion 13 mainly having no mask is etched by the first etching step. The base material 7 for the lower portion of the mask 12 is not etched from the surface of the base material for the die but the etching proceeds from the region 13 without the mask as the etching progresses. Therefore, near the boundary between the mask 12 and the maskless region 13, the mold base material 7 under the mask 12 is also etched. In the vicinity of the boundary between the mask 12 and the maskless region 13, the substrate for the mold base 7 under the mask 12 is also etched, hereinafter referred to as side etching. Fig. 13 schematically shows the progress of the side etching. The dotted line 14 in Fig. 13 shows the surface of the mold base material which changes with the progress of etching stepwise.

The etching treatment in the first etching step is usually carried out by using a solution of ferric chloride (FeCl ₃ ), cupric chloride (CuCl ₂ ), an alkali etching solution (Cu (NH ₃ ) ₄ Cl ₂ ) But it is also possible to use a strong acid such as hydrochloric acid or sulfuric acid or use an inverse electrolytic etching by applying a potential opposite to that at electrolytic plating. The concave shape formed on the mold base material when the etching treatment is performed can not be uniformly determined because it depends on the kind of the base metal, the type of the photosensitive resin film, the etching method, and the like. When the etching amount is 10 m or less, Is etched approximately isotropically from the metal surface in contact. The etching amount referred to here is the thickness of the substrate which is etched by etching.

The amount of etching in the first etching step is preferably 1 m to 50 m. When the etching amount is less than 1 占 퐉, the concavo-convex shape is hardly formed on the metal surface, resulting in a substantially flat metal mold, resulting in no display of the antireflection property. When the etching amount is more than 50 占 퐉, the height difference of the concavo-convex shape formed on the metal surface becomes large, and the antiglare film produced by using the obtained metal mold becomes whitish. The etching treatment in the first etching step may be performed by one etching treatment, or may be performed by dividing the etching treatment two or more times. In the case where the etching treatment is divided into two or more times, it is preferable that the total etching amount in two or more etching treatments is 1 占 퐉 to 50 占 퐉.

[7] Photosensitive resin film peeling step

In the subsequent photosensitive resin film peeling step, the remaining photosensitive resin film used as a mask in the first etching step is completely dissolved and removed. In the photosensitive resin film peeling step, the photosensitive resin film is dissolved by using a peeling liquid. As the peeling solution, the same developer as the above-mentioned developing solution can be used. By changing the pH, temperature, concentration and immersion time or the like, when a negative photosensitive resin film is used, when a positive photosensitive resin film is used, Of the photosensitive resin film is completely dissolved and removed. The method of peeling in the photosensitive resin film peeling step is not particularly limited, and a method such as immersion phenomenon, spray phenomenon, brush phenomenon, and ultrasonic phenomenon can be used.

Fig. 12 (b) schematically shows a state in which the photosensitive resin film used as the mask in the first etching step is completely dissolved and removed by the photosensitive resin film peeling step. The first surface irregularities 15 are formed on the surface of the mold base material by the mask 12 and the etching with the photosensitive resin film.

[8] Second plating process

Subsequently, chromium plating is performed to make the concavo-convex shape of the surface blunt. 12 (c) shows a state in which the chromium plating layer 16 is formed on the surface irregularities formed by the etching treatment in the first etching step and the surface 17 is made dull.

In the production method of this mold, chrome plating is used which is glossy on the surface of a flat plate or a roll, has a high hardness, a small coefficient of friction, and can give good releasability. The type of chromium plating is not particularly limited, but it is preferable to use chromium plating which is called glossy chromium plating or decorative chromium plating and which exhibits good gloss. Chromium plating is usually carried out by electrolysis. As the plating bath, an aqueous solution containing chromic anhydride (CrO ₃ ) and a small amount of sulfuric acid is used. By adjusting the current density and the electrolysis time, the thickness of the chromium plating can be controlled.

The above-mentioned Japanese Patent Application Laid-Open Nos. 2002-189106, 2004-45472, 2004-90187 and the like disclose adopting chromium plating. However, Depending on the kind of the chromium plating, the surface roughness after plating or a lot of minute cracks due to chromium plating often occurs. As a result, the optical characteristic of the produced antiglare film proceeds in an undesirable direction. A metal mold in which the plating surface is roughened is not suitable for producing an antiglare film. This is because polishing of the surface of the plating is generally performed after chrome plating in order to eliminate lint, but as described later, polishing of the surface after plating is undesirable in the present invention. In this manufacturing method of the mold, copper plating or nickel plating is performed on the underlying metal to solve such a problem that is likely to occur in chromium plating.

Further, in the second plating step, plating other than chromium plating is not preferable. This is because, in plating other than chromium, the hardness and the abrasion resistance are lowered, so that the durability as a mold is lowered, and irregularities are worn out during use, and the metal mold is damaged. In the antiglare film obtained from such a mold, there is a high possibility that a sufficient antiglare function is hardly obtained, and the possibility of occurrence of defects on the film also increases.

Furthermore, as disclosed in the above-mentioned Japanese Patent Laid-Open Publication No. 2004-90187, it is not preferable to polish the surface after plating as well. There is a possibility that the optical characteristic may be deteriorated because a flat portion is generated on the outermost surface by grinding and that control of shape is increased and shape control with good reproducibility becomes difficult All.

As described above, in the manufacturing method of the metal mold, after chrome plating, it is preferable to use the chromium plated surface as the uneven surface of the metal mold without grinding the surface. This is because chromium plating is applied to the surface on which the fine concavo-convex shape is formed, so that the convexo-concave shape becomes dull and a metal mold having increased surface hardness is obtained. The irregularity of the irregularities at this time differs depending on the kind of the base metal, the size and depth of the irregularities obtained by the first etching step, the type and thickness of the plating, and so on. The greatest factor is also the thickness of the plating. If the thickness of the chromium plating is small, the effect of dulling the surface shape of the irregularities obtained before chrome plating is insufficient, and the optical characteristics of the antiglare film obtained by transferring the irregular shape to the transparent film are not improved much. On the other hand, if the plating thickness is excessively large, productivity is deteriorated and a plating defect of a projection-like shape called a nodule is generated, which is not preferable. Therefore, the thickness of the chromium plating is preferably in the range of 1 탆 to 10 탆, more preferably in the range of 3 탆 to 6 탆.

The chromium plating layer formed in the second plating step is preferably formed so as to have a Vickers hardness of 800 or more, more preferably 1000 or more. When the Vickers hardness of the chromium plated layer is less than 800, the durability in use of the mold is lowered and the hardness is lowered by the chromium plating because there is a high possibility that the plating bath composition and the electrolytic conditions are abnormal during the plating process, Is likely to have an undesirable effect on the occurrence status of the product.

Further, in the method of manufacturing a mold for producing the antiglare film of the present invention, the uneven surface formed by the first etching step is etched between the photosensitive resin film peeling step [7] and the [8] second plating step described above And a second etching step of blunting by a treatment. In the second etching step, the first surface irregularities 15 formed by the first etching step using the photosensitive resin film as a mask are etched by etching. By this second etching treatment, the portion of the first surface concave-convex shape 15 formed by the first etching treatment disappears and the optical characteristics of the antiglare film produced by using the obtained mold disappear in a preferred direction Change. 14 shows that the first surface irregularity 15 of the substrate 7 is reduced by the second etching treatment and the second surface irregularity shape 18 having a gentle surface inclination ) Is formed on the substrate.

The etching treatment of the second etching step is also conducted in the same manner as in the first etching step except that a ferric chloride (FeCl ₃ ) solution, a cupric chloride (CuCl ₂ ) solution, an alkaline etching solution (Cu (NH ₃ ) ₄ Cl ₂ ) Or the like. However, a strong acid such as hydrochloric acid or sulfuric acid may be used, or an inverse electrolytic etching by applying a potential opposite to that at electrolytic plating may be used. Since the irregularity of the irregularities after the etching treatment varies depending on the kind of the underlying metal, the etching method, and the size and depth of the irregularities obtained by the first etching step, it can not be said uniformly. However, The largest factor is the etching amount. The amount of etching referred to here is the thickness of the base material to be ground by etching as in the first etching step. If the etching amount is small, the effect of dulling the surface shape of the irregularities obtained by the first etching step is insufficient, and the optical characteristics of the antiglare film obtained by transferring the irregular shape to the transparent film are not so improved. On the other hand, if the etching amount is excessively large, the irregular shape is almost lost and the metal becomes a substantially flat mold, so that it does not exhibit flicker resistance. Therefore, the etching amount is preferably in the range of 1 탆 to 50 탆, more preferably in the range of 4 탆 to 20 탆. The etching treatment in the second etching step may be performed by one etching treatment as in the first etching step, or may be performed by dividing the etching treatment into two or more times. In the case where the etching treatment is divided into two or more times, it is preferable that the total etching amount in two or more etching treatments is 1 占 퐉 to 50 占 퐉.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In the examples, "%" and "parts" indicating the content or amount are based on weight unless otherwise specified. The evaluation method of the mold or the antiglare film in the following examples is as follows.

[1] Measurement of surface shape of antiglare film

The surface morphology of the antiglare film was measured using a three-dimensional microscope PL 占 2300 (manufactured by Sensofar Inc.). In order to prevent the sample from warping, an optically transparent pressure-sensitive adhesive was applied to the glass substrate so that the uneven surface became the surface, and was provided for the measurement. At the time of measurement, the magnification of the objective lens was measured at 10 times. The horizontal resolutions [Delta] x and [Delta] y were both 1.66 mu m and the measurement area was 850 mu m x 850 mu m.

(Ratio of energy spectra H ₁ ² / H ₂ ² and H ₃ ² / H ₂ ² )

From the measurement data obtained above, to obtain a fine irregular surface of the antiglare film elevation a two-dimensional function, h (x, y), a two-dimensional function, h (x, y) to the discrete Fourier transform, two-dimensional function H (f _x, f _y) obtained Respectively. Two-dimensional function H (f _x, f _y) square by calculating a two-dimensional function of the energy spectrum ^{_{H 2 (f x, f y}} ), f x = 0 cross-sectional curve in H ² (0, f _y) from, the space the energy spectrum and the spatial frequency H ₁ ^{2 -1} 0.04 ㎛ energy spectrum H ₂ seek to Figure ^2, non-H ^2, the energy spectrum _1/2 H ² in the calculated according to the frequency 0.01 ㎛ ^-1. Further, the energy spectrum H ₃ ² at a spatial frequency of 0.1 μm ^-1 was obtained, and the ratio H ₃ ² / H ₂ ² of the energy spectrum was also calculated.

(Inclination angle of the surface of fine unevenness)

Based on the measurement data obtained above, calculation is made on the basis of the above-described algorithm to create a bar graph of the inclination angle of the uneven surface, obtain the distribution for each inclination angle from the bar graph, calculate the ratio of the inclination angle of 5 or less Respectively.

[2] Measurement of Optical Properties of Antiglare Film

(Hayes)

The haze of the antiglare film was measured by the method specified in JIS K 7136. Specifically, the haze was measured using a haze meter HM-150 (manufactured by Murakami Color Research Laboratory) conforming to this standard. In order to prevent warpage of the antiglare film, an optically transparent pressure-sensitive adhesive was used to bond the glass substrate so that the uneven surface became the surface, and then the film was provided for measurement. Generally, when the haze becomes large, the image becomes dark when applied to the image display apparatus, and as a result, the front contrast tends to decrease. Therefore, it is preferable that the haze is low.

[3] Evaluation of Antiglare Performance of Antiglare Film

(Projection, naked eye evaluation of whiteness)

In order to prevent reflection from the back surface of the antiglare film, the antiglare film was bonded to the black acrylic resin plate so that the uneven surface became the surface, and the naked eye was observed from the uneven surface side in the bright room where the fluorescent lamp was lit, Was assessed visually. The projections, whiteness and texture were evaluated in three steps of 1 to 3, respectively, according to the following criteria.

Projection 1: Projection is not observed.

      2: Projection is slightly observed.

      3: Projection is clearly observed.

Bleach 1: No whitening is observed.

      2: White pigment is slightly observed.

      3: Whiteness is clearly observed.

(Evaluation of flashing)

The glare was evaluated in the following manner. Namely, the polarizing plates on both sides of the front and back sides were peeled off from a commercially available liquid crystal television LC-32GH3 (manufactured by Sharp Corporation). In place of these original polarizing plates, a polarizing plate Sumikaran SRDB31E (manufactured by Sumitomo Chemical Co., Ltd.) was bonded to both the back side and the display surface side through an adhesive so that the absorption axes thereof coincided with the absorption axes of the original polarizing plates, On the surface side polarizing plate, the antiglare film shown in each of the following examples was bonded through a pressure-sensitive adhesive so that the uneven surface became the surface. In this state, the sample was visually observed from a position about 30 cm away from the sample, and the degree of glare was evaluated in seven steps. Level 1 is a state in which no glare is visible, Level 7 is a state in which a glaring glare is observed, and Level 3 is a state in which a slight glare is observed.

[4] Evaluation of patterns for producing antiglare film

The generated pattern data is image data of 256 gray scales, and the gray scales are expressed as a two-dimensional discrete function g (x, y). The horizontal resolutions? X and? Y of the discrete function g (x, y) are all 2 占 퐉. The obtained two-dimensional function g (x, y) is subjected to discrete Fourier transform to obtain a two-dimensional function G (f _x , f _y ). Two-dimensional function G (f _x, f _y) square by calculating a two-dimensional function of the energy spectrum ^{_{G 2 (f x, f y}} ), f x = 0 cross section curve of G, the space from the ² (0, f _y) of The maximum value at a spatial frequency with a frequency larger than 0 占 퐉 ^-1 and the absolute value being the smallest was obtained.

&Lt; Example 1 >

A surface of an aluminum roll (A5056 according to JIS) having a diameter of 200 mm was plated with copper ballard. The copper ballard plating is composed of a copper plating layer / a thin silver plating layer / a surface copper plating layer, and the thickness of the entire plating layer is set to be about 200 占 퐉. The copper-plated surface was mirror-polished, a polished copper-plated surface was coated with a photosensitive resin, and dried to form a photosensitive resin film. Subsequently, a pattern in which the patterns shown in FIG. 8 are repeatedly arranged was exposed on the photosensitive resin film by laser light and developed. Exposure by laser light and development were performed using Laser Stream FX (manufactured by Synkro Laboratories). A positive photosensitive resin was used for the photosensitive resin film.

Thereafter, the first etching treatment was performed with a cupric chloride solution. The etching amount at that time was set to be 7 占 퐉. The photosensitive resin film was removed from the roll after the first etching treatment, and the second etching treatment was again performed with the cupric chloride solution. The etching amount at that time was set to be 18 탆. Thereafter, chromium plating was carried out to prepare a mold A. At this time, the chromium plating thickness was set to be 4 탆.

The photo-curing resin composition GRANDIC 806T (manufactured by Dainippon Ink and Chemicals, Inc.) was dissolved in ethyl acetate to prepare a solution having a concentration of 50% by weight and a photocuring initiator, lucylline TPO (manufactured by BASF, chemical name: 2 , 4,6-trimethylbenzoyldiphenylphosphine oxide] was added in an amount of 5 parts by weight per 100 parts by weight of the curable resin component to prepare a coating liquid. This coating liquid was applied on a triacetylcellulose (TAC) film having a thickness of 80 탆 so that the coating thickness after drying was 10 탆 and dried in a drier set at 60 캜 for 3 minutes. The dried film was pressed against the uneven surface of the previously obtained mold A by rubber roll so that the photo-curable resin composition layer was on the mold side, and adhered. In this state, light from a high-pressure mercury lamp with a strength of 20 mW / cm 2 was irradiated from the TAC film side so as to have a h-converted light quantity of 200 mJ / cm 2 to cure the photocurable resin composition layer. Thereafter, the TAC film was peeled from the mold together with the cured resin to prepare a transparent antiglare film A comprising a laminate of a cured resin having a concavo-convex surface and a TAC film.

&Lt; Example 2 >

A mold B was obtained in the same manner as in Example 1 except that the pattern shown in Fig. 15 was used as a pattern to be exposed by laser light. The image data, which is a pattern shown in Fig. 15, has a size of 1 mm x 1 mm and is formed at 6400 dpi. An antiglare film B was produced in the same manner as in Example 1 except that the obtained mold B was used.

&Lt; Comparative Example 1 &

A mold C was obtained in the same manner as in Example 1 except that the pattern shown in Fig. 16 was used as a pattern to be exposed by laser light. The image data, which is a pattern shown in Fig. 16, has a size of 2 mm x 2 mm and is created at 12800 dpi. An antiglare film C was produced in the same manner as in Example 1 except that the obtained mold C was used.

&Lt; Comparative Example 2 &

The pattern shown in Fig. 17 was used as a pattern to be exposed by the laser beam, and the etching amount of the first etching treatment was set to be 10 占 퐉 and the etching amount of the second etching treatment was set to be 30 占 퐉 A mold D was obtained in the same manner as in Example 1. The image data, which is the pattern shown in Fig. 17, has a size of 20 mm x 20 mm and is formed at 3200 dpi. An antiglare film D was produced in the same manner as in Example 1 except that the obtained mold D was used.

&Lt; Comparative Example 3 &

(A5056 according to JIS) having a diameter of 200 mm was coated with copper ballard. The copper ballard plating is composed of a copper plating layer / a thin silver plating layer / a surface copper plating layer, and the thickness of the entire plating layer is set to be about 200 占 퐉. The copper-plated surface was mirror-polished and the polished copper-plated surface was treated with zirconia beads TZ-SX-17 (manufactured by TOSOH CORPORATION; average particle diameter: 20 mm) using a blast apparatus (manufactured by Fuji Seisakusho Co., Was blasted with a blast pressure of 0.05 MPa (gauge pressure, the same applies hereinafter) and an amount of beads used of 8 g / cm 2 (the amount used per 1 cm 2 of the surface area of the roll, hereinafter the same). A copper-plated aluminum roll having the obtained unevenness was chrome-plated to produce a metal mold E. At this time, the chromium plating thickness was set to be 6 占 퐉. An antiglare film E was produced in the same manner as in Example 1 except that the obtained mold E was used.

&Lt; Comparative Example 4 &

The surface of an aluminum roll (A5056 by JIS) having a diameter of 300 mm was mirror-polished and the polished aluminum surface was treated with zirconia beads TZ-SX-17 [Toso Co., Ltd. Blasted with a blast pressure of 0.1 MPa (gauge pressure, the same applies hereinafter) and an amount of beads used of 8 g / cm 2 (the amount per 1 cm 2 of the surface area of the roll, hereinafter the same) . An electroless nickel plating process was performed on the obtained aluminum roll having the unevenness to prepare a mold F. [ At this time, the electroless nickel plating thickness was set to be 15 占 퐉. An antiglare film F was produced in the same manner as in Example 1 except that the obtained mold F was used.

The results are shown in Table 1. In addition, it shows a cross-section of the f _x = 0 of the energy spectra obtained from the two-dimensional function representing the elevation of the minute uneven surface of the antiglare film B~F in Fig. In addition, it shows a cross-section of the f _x = 0 of the energy spectrum resulting from a pattern used in the production of an anti-glare film B~D in Fig. The energy spectrum of the pattern used for the production of an anti-glare film from a B 19 it can be seen that the spatial frequency does not have a maximum value in less than 0 ㎛ ^-1 0.04 ㎛ ^-1. In comparison, the energy spectrum of the pattern used in the manufacture of anti-glare films C and D it can be seen that having a spatial frequency less than the maximum value to 0 ㎛ ^-1 exceeds 0.04 ㎛ ^-1.

From the results shown in Table 1, the antiglare films A and B satisfying all the requirements of the present invention did not cause glare, exhibited sufficient antifogging property, and did not cause whitening. In addition, since the haze is also low, the contrast is not lowered even when the image display device is disposed. Since the energy spectrum anti-glare film C and D made from the pattern having the maximum value in less than 0.04 ^-1 0 ^-1 ㎛ ㎛ is, the ratio H _{1 ²} / H ^{2 2} of the energy spectrum does not meet the requirements of the present invention, sufficient And there was no whitening, but glare occurred. Further, the antiglare films E and F prepared without using a predetermined pattern could not satisfy both the sufficient spectral sensitivity and the suppression of glare because the energy spectrum ratio H ₁ ² / H ₂ ² did not satisfy the requirements of the present invention .

Claims (4)

An antiglare film comprising a transparent support and an antiglare layer having a fine irregular surface formed thereon, the antiglare film comprising an energy spectrum H ₁ ^{2 at} a spatial frequency of 0.01 μm ^-1 at an elevation (height) of the fine irregular surface, ^-1 spectral energy ratio H ₂ ² H _{1 ²} / H ^{2 2} is within the range of 3 to 15 of the anti-glare film according to the. The method according to claim ¹ , wherein the energy spectrum H ₃ ^{2 at} the spatial frequency of 0.1 μm ^-1 at the elevation of the fine uneven surface and the ratio H ₃ ² / H of the energy spectrum H ₂ ^{2 at} the spatial frequency of 0.04 μm ^-1 _{2 &lt; 2 &} ^gt; is 0.01 or less. The antiglare film according to any one of claims 1 to 3, wherein the ratio of the surface of the fine irregular surface having an inclination angle of 5 or less is 95% or more. The antiglare film according to claim 1, wherein when the antiglare layer contains fine particles, the fine particles are less than 0.4 탆.

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