TWI498603B - Antiglare film and antiglare polarizing sheet - Google Patents

Description

Anti-glare film and anti-glare polarizer

The present invention relates to an anti-glare (antiglare) film and an anti-glare polarizing plate using the same.

An image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT (Cathode Ray Tube)) display, or an organic electroluminescence (EL) display, when external light is mapped to the display surface, Will significantly damage the viewing. In order to prevent such mapping of external light, cameras and digital cameras that are used in outdoor lighting, digital cameras that are used outdoors, and mobile phones that use reflected light for display have been used in the past. The surface of the image display device is provided with an anti-glare film for preventing the mapping of external light.

For example, JP-A-2006-053371 discloses that a mold for a polished mold base is subjected to sandblasting, and then electroless nickel plating is applied to produce a mold having fine irregularities on the surface, and then The photocurable resin layer formed on the cellulose triacetate (TAC: Triacetyl Cellulose) is cured while being pressed against the uneven surface of the mold, whereby the uneven surface of the mold is transferred onto the surface of the photocurable resin layer. Anti-glare film.

For the anti-glare film, in addition to the anti-glare property, it is also desirable to exhibit high contrast when disposed on the surface of the image display device, and when disposed on the surface of the image display device, it is possible to suppress the display surface from being changed by the scattered light. The generation of the so-called "whitening" which shows the turbidity, and the arrangement of the surface of the image display device can suppress the occurrence of the brightness distribution due to the interference of the surface unevenness of the pixel of the image display device and the anti-glare film. The production of so-called "flash spots" that are difficult to watch. However, the anti-glare film described in the above-mentioned Japanese Patent Publication No. 2006-053371 is produced by using a mold which is formed into a concave-convex shape by sandblasting, so that the accuracy of the uneven shape formed on the anti-glare film is insufficient, and in particular, Since a relatively large uneven shape having a period of 50 μm or more is produced, there is a problem that "flash spots" are likely to occur.

Further, the anti-glare film described in the same document is liable to cause damage, and is not necessarily sufficient from the viewpoint of mechanical strength. In addition, the anti-glare film described in the same document has insufficient moisture resistance, and when the anti-glare film is bonded to a polarizing film, the polarizing film may be deteriorated by moisture absorption.

Accordingly, it is an object of the present invention to provide an anti-glare film which can exhibit better anti-glare properties and exhibit good contrast, and can prevent deterioration of visibility due to "whitening" and "flash spots". And an anti-glare polarizing plate which is an anti-glare polarizing plate which is composed of a laminate of the anti-glare film and the polarizing film, and can effectively suppress deterioration of the polarizing film. .

The present invention provides an anti-glare film comprising: a base film; and an anti-glare layer laminated on the base film and having an uneven surface, wherein the base film contains an acrylic resin; and the spatial frequency is 0.01 μm ^-1 the irregularities in the surface elevation of the spectra H ₁ ² in the spatial frequency spectrum of the elevation of the surface irregularities of 0.04μm ^-1 H _{² 2} in the range of 3 to 20 the ratio of H _{1 ²} / H ^{2 2,} based The ratio of the energy spectrum H ₃ ² of the elevation of the relief surface in the spatial frequency 0.1 μm ^-1 to the energy spectrum H ₂ ² of the elevation of the relief surface in the spatial frequency 0.04 μm ^-1 H ₃ ² /H ₂ ² The surface of the uneven surface contains 95% or more of a surface having an inclination angle of 5 or less. The thickness of the base film is preferably 20 μm or more and 100 μm or less.

Furthermore, the present invention provides an anti-glare polarizing plate comprising the anti-glare film and a polarizing film laminated on a surface of the base film opposite to the anti-glare layer.

The anti-glare film of the present invention can exhibit better anti-glare properties and exhibit good contrast, and can effectively prevent deterioration of visibility due to the occurrence of "whitening" and "flash spots". Further, the antiglare film of the present invention is excellent in mechanical strength and moisture resistance. In the anti-glare polarizing plate of the present invention using the anti-glare film, deterioration of the polarizing film due to moisture absorption can be effectively suppressed.

<anti-glare film>

Fig. 1 is a cross-sectional view schematically showing an example of an anti-glare film of the present invention. The antiglare film of the present invention, as shown in Fig. 1, includes a base film 101 containing an acrylic resin and an antiglare layer 102 laminated on the base film 101. The surface of the anti-glare layer 102 on the opposite side to the base film 101 is composed of a fine uneven surface (fine uneven surface 103). The anti-glare film of the present invention will be described in more detail below.

(anti-glare layer)

In the antiglare layer 102 provided in the antiglare film of the present invention, the energy spectrum H ₁ ² of the level of the fine uneven surface 103 in the spatial frequency of 0.01 μm ^-1 and the height of the fine uneven surface 103 in the spatial frequency of 0.04 μm ^-1 The energy spectrum H ₂ ² ratio H ₁ ² /H ₂ ² is in the range of 3 to 20, and the energy spectrum H ₃ ² and the spatial frequency of 0.04 μm of the level of the fine uneven surface 103 in the spatial frequency of 0.1 μm ^-1 The ratio H ₃ ² /H ₂ ² of the energy spectrum H ₂ ² of the level of the fine uneven surface 103 in ^-1 is 0.1 or less.

In the past, the period of the fine uneven surface of the anti-glare film is evaluated by the average length RSm of the roughness curve elements described in JIS B 0601, the average length PSm of the profiled curve elements, and the average length WSm of the curved curve elements. . However, in such conventional evaluation methods, it is not possible to correctly evaluate the plurality of cycles included in the surface of the fine uneven surface. Therefore, the correlation between the speckle and the fine uneven surface and the correlation between the anti-glare property and the fine uneven surface cannot be correctly evaluated. Under the control of the values of RSm, PSm, WSm, etc., it is difficult to produce both An anti-glare film with suppression of flash spots and sufficient anti-glare properties.

The present inventors have found that in the anti-glare film in which the antiglare layer having the fine uneven surface is laminated on the base film containing the acrylic resin, the fine uneven surface exhibits the use of the "fine surface of the fine uneven surface". predetermined specific spatial frequencies of the spectrum "distribution, i.e., elevation of spectrum in the range of 3 to 20 ratio _{^{H 1 2 / H 2 2,}} 0.1 or less of the antiglare film and H _{3 ²} / H ^{2 2} to be It exhibits better anti-glare performance and prevents deterioration of visibility due to whitening, and even when applied to a high-definition image display device, no speckle is generated and high contrast can be exhibited.

First, the energy spectrum of the level of the fine uneven surface of the anti-glare film will be described. Fig. 2 is a perspective view schematically showing the surface of the anti-glare film of the present invention. As shown in FIG. 2, the anti-glare film 1 of the present invention includes an anti-glare layer having a fine uneven surface composed of fine unevenness 2. Here, the "elevation of the fine uneven surface" in the present invention means that the height of the lowest point of the fine uneven surface in the arbitrary point P on the surface of the anti-glare film 1 is from the virtual plane having the height (the elevation system) The linear distance of the main normal direction 5 (the normal direction of the imaginary plane) of the anti-glare film based on 0 μm. As shown in Fig. 2, when the orthogonal coordinates in the plane of the anti-glare film are represented by (x, y), the elevation of the fine concave-convex surface can be represented by the two-dimensional function h(x, y) of the coordinates (x, y). Said. In Fig. 2, the entire surface of the anti-glare film is indicated by the projection surface 3.

The elevation of the fine uneven surface can be obtained from three-dimensional information of the surface shape measured by a device such as a confocal microscope, an interference microscope, or an atomic force microscope (AFM). The horizontal decomposition energy required for the measuring machine is at least 5 μm or less, preferably 2 μm or less, and the vertical decomposition energy is at least 0.1 μm or less, preferably 0.01 μm or less. The non-contact three-dimensional surface shape and the roughness measuring machine suitable for the measurement include a New View 5000 series (manufactured by Zygo Corporation, available from Zygo Co., Ltd. in Japan), a three-dimensional microscope PLμ2300 (manufactured by Sensofar Co., Ltd.), and the like. . Regarding the measurement area, since the decomposition energy of the energy spectrum of the elevation must be 0.01 μm ^-1 or less, it is preferably at least 200 μm × 200 μm or more, and more preferably 500 μm × 500 μm or more.

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

Here, f _x and f _y are spatial frequencies in the x direction and the y direction, respectively, and have a dimension having a reciprocal of length. Further, π in the formula (1) is a pi, and i is an imaginary unit. By averaging the obtained two-dimensional function H(f _x , f _y ), the energy spectrum H ² (f _x , f _y ) of the elevation can be obtained. This energy spectrum H ² (f _x , f _y ) represents the spatial frequency distribution of the fine uneven surface of the anti-glare film.

Hereinafter, a method of obtaining an energy spectrum of the level of the fine uneven surface of the anti-glare film will be more specifically described. The three-dimensional information of the surface shape actually measured by the confocal microscope, the interference microscope, the atomic force microscope, or the like can be generally obtained as a discrete value, that is, an elevation corresponding to a plurality of measurement points. Fig. 3 is a schematic diagram showing a state in which the function h(x, y) indicating the elevation is discretely obtained. As shown in Fig. 3, the orthogonal coordinates in the plane of the anti-glare film are indicated by (x, y), and the line divided by Δx in the x-axis direction on the projection surface 3 of the anti-glare film is indicated by a broken line. And in the case of a line divided by Δy in the y-axis direction, in actual measurement, the elevation of the fine uneven surface can be used as a discrete elevation value of each intersection of each broken line on the projection surface 3 of the anti-glare film. obtain.

The number of the obtained elevation values is determined by the measurement range and Δx and Δy. As shown in Fig. 3, 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 (M+1) × (N + 1).

As shown in FIG. 3, when the coordinate of the eye point A on the projection surface 3 of the anti-glare film is (jΔx, kΔy) (here, j is 0 or more and M or less, and k is 0 or more and N or less), The elevation of the point P on the surface of the anti-glare film corresponding to the point of view A can be expressed as h(jΔx, kΔy).

Here, the measurement intervals Δx and Δy are dependent on the horizontal decomposition energy of the measuring device, and the fine uneven surface is evaluated for accuracy. As described above, Δx and Δy are preferably 5 μm or less, and particularly preferably 2 μm or less. Further, the measurement ranges X and Y are preferably 200 μm or more, and more preferably 500 μm or more, as described above.

As described above, in the actual measurement, the function indicating the elevation of the fine uneven surface can be obtained as a discrete function h(x, y) having (M+1) × (N+1) values. Therefore, the discrete function H(f _x , f _y ) is obtained by the discrete function h(x, y) obtained by the measurement and the discrete Fourier transform defined by the following formula (2), and by discretizing The function H(f _x , f _y ) is squared to obtain the discrete function H ² (f _x , f _y ) of the energy spectrum. 1 in the formula (2) is an integer of -(M+1)/2 or more and (M+1)/2 or less, and m is an integer of -(N+1)/2 or more (N+1)/2 or less. Further, Δf _x and Δf _y are spatial frequency intervals in the x direction and the y direction, respectively, and are defined by the equations (3) and (4), respectively. Δf _x and Δf _y correspond to the horizontal decomposition energy of the energy spectrum of the elevation.

Fig. 4 is a view showing an example of the elevation of the fine uneven surface of the antiglare layer of the antiglare film of the present invention by a two-dimensional discrete function h(x, y). In Fig. 4, the elevation is expressed in terms of white and black gradations. The discrete function h(x, y) shown in Fig. 4 has 512 × 512 values, and the horizontal decomposition energy Δx and Δy are 1.66 μm.

In addition, Fig. 5 shows the energy spectrum H ² (f _x , f _y ) of the elevation obtained by discrete Fourier transform of the two-dimensional function h(x, y) shown in Fig. 4 in white and black _gradation . Picture. The energy spectrum H ² (f _x , f _y ) of the elevation shown in Fig. 5 is also a discrete function having 512 × 512 values, and the horizontal decomposition energies Δf _x and Δf _y of the energy spectrum of the elevation are 0.0012 μm ^-1 .

As shown in Fig. 4, since the fine uneven surface of the antiglare layer provided in the antiglare film of the present invention is composed of randomly formed irregularities, the energy spectrum H ² of the elevation is as shown in Fig. 5. It is symmetrical with the origin as the center. Therefore, the energy spectrum H ₁ ² and the spatial frequency of 0.04 μm in the spatial frequency of 0.01 μm ^-1 can be obtained from the profile of the origin through the energy spectrum H ² (f _x , f _y ) belonging to the two-dimensional function. ^-1 spectrum of the elevation H _{² 2} and 0.1 m of the spatial frequency spectrum elevation ^-1 H ₃ ^2. Fig. 6 is a view showing a cross section of f _x =0 in the energy spectrum H ² (f _x , f _y ) shown in Fig. 5. It can be seen from Fig. 6 that the energy spectrum H ₁ ² of the elevation in the spatial frequency of 0.01 μm ^-1 is 4.4, and the energy spectrum H ₂ ² of the elevation in the spatial frequency of 0.04 μm ^-1 is 0.35, and the spatial frequency is 0.1 μm ^- the level ¹ is H ₃ ² 0.00076 spectrum than H _{1 ²} / H ^{2 2} to 14, than H _{3 ²} / H ^{2 2} 0.0022.

As described above, in the antiglare film of the present invention, the ratio H of the elevation spectrum H ₁ ² of the fine uneven surface in the spatial frequency of 0.01 μm ^-1 to the energy spectrum H ₂ ² of the elevation in the spatial frequency of 0.04 μm ^-1 _{1 ²} / H ^{2 2} is set within a range of 3 to 20. When the ratio H ₁ ² /H ₂ ² of the energy spectrum of the elevation is less than 3, it is shown that the uneven surface of the long period of 100 μm or more contained in the fine uneven surface of the antiglare layer is small, and the unevenness of the short period of 25 μm is less. More shapes. At this time, the mapping of external light cannot be effectively prevented, and sufficient anti-glare performance cannot be obtained. On the other hand, in the case where the ratio H ₁ ² /H ₂ ² of the energy spectrum of the elevation is higher than 20, the long-period shape of the long period of 100 μm or more contained in the surface of the fine uneven surface is large, and the short period of 25 μm or less is short. The shape of the bump is less. At this time, when the anti-glare film is disposed in a high-definition image display device, there is a tendency to generate a flare. In order to exhibit better anti-glare properties and more effectively suppress the flare, the energy spectrum ratio H ₁ ² /H ₂ ^{2 of the} elevation is preferably in the range of 5 to 18, more preferably in the range of 8 to 15.

Further, in the antiglare film of the present invention, the ratio H ₃ ² of the energy spectrum H ₃ ² of the fine uneven surface in the spatial frequency of 0.1 μm ^-1 to the energy spectrum H ₂ ² of the elevation in the spatial frequency of 0.04 μm ^-1 is H ₃ ² /H ₂ ² is set to 0.1 or less, preferably 0.01 or less. When the ratio of H ₃ ² /H ₂ ² is 0.1 or less, it is shown that the short-period component of less than 10 μm contained in the surface of the fine uneven surface can be sufficiently reduced, whereby the occurrence of whitening can be effectively suppressed. The short-period component of less than 10 μm contained in the fine uneven surface not only does not effectively impart anti-glare properties, but also causes light incident on the surface of the fine uneven surface to scatter white light.

In the conventional anti-glare film described in Japanese Laid-Open Patent Publication No. 2006-053371, the energy spectrum H ₁ ² and the spatial frequency of 0.04 μm ^{-1 of the} surface of the fine uneven surface in the spatial frequency of 0.01 μm ^-1 are obtained. elevation in the spectrum ratio H _{² 2} H _{1 ²} / H ^{2 2} greater than the present application, it is easy to spot the flash problem. Therefore, in order to set the ratio H ₁ ² /H ₂ ² in the range of 3 to 20, it is necessary to lower the energy spectrum H ₁ ² of the level of the fine uneven surface in the spatial frequency of 0.01 μm ^-1 . In this way, the anti-glare film having the fine uneven surface on which the energy spectrum H ₁ ^{2 of the} surface of the fine uneven surface in the spatial frequency of 0.01 μm ^-1 is lowered can be displayed at a spatial frequency of more than 0 μm by using - as will be described later ^- spectrum does not have a maximum value of ¹ and the pattern is a range of 0.04μm ^-1 or less, ideally fabricated. Here, the "pattern" generally means a second-order tone (for example, binarized image data of white and black) which is used by a computer for forming a fine uneven surface of an anti-glare film. Or image data composed of gradations above the 3rd order, but may also contain data (array, etc.) that can be converted into the image data in a single meaning. It can be converted into data of image data in a single sense, such as coordinates of each pixel and data of only the tone.

Thus, by using a pattern showing an energy spectrum having no maximum value in a range in which the spatial frequency is larger than 0 μm ^-1 and 0.04 μm ^-1 or less, the fine uneven surface of the anti-glare film can be formed, and the spatial frequency can be effectively reduced by 0.01. The energy spectrum H ₁ ² of the level of the fine uneven surface in μm ^-1 is set to be in the range of 3 to 20 than H ₁ ² /H ₂ ² .

Further, in order to obtain a spatial frequency spectrum having a fine uneven surface of 0.1μm ^-1 H ₃ ² elevation of 0.04μm spatial frequency spectrum of the ^level-1 ratio of H _{² 2} H _{3 ²} / H ^{2 2} The antiglare film having a fine uneven surface of 0.1 or less, the energy spectrum of the pattern is preferably a maximum value in a range in which the spatial frequency is larger than 0.04 μm ^-1 and less than 0.1 μm ^-1 . By forming the fine uneven surface of the anti-glare film using the pattern having such a spectrum, the energy spectrum H ₂ ² of the level of the fine uneven surface in the spatial frequency of 0.04 μm ^-1 can be effectively increased, and the ratio H _{3 is obtained.} ² /H ₂ ^{2 is} set to 0.1 or less.

A method of forming a fine uneven surface of an anti-glare film using such a pattern, preferably using the pattern to form a mold having a concave-convex surface, and transferring the uneven surface of the mold to a resin layer formed on the base film Surface method (embossing method).

The present inventors have further found that the fine uneven surface of the antiglare layer exhibits a specific distribution of the oblique angle, exhibits better antiglare performance, and is more effective in preventing whitening. In other words, in the antiglare film of the present invention, the fine uneven surface of the antiglare layer contains 95% or more of a surface having an inclination angle of 5 or less. When the ratio of the surface of the fine uneven surface having an inclination angle of 5 or less is less than 95%, the inclination angle of the uneven surface becomes steep, and the light from the surroundings is concentrated, which tends to cause whitening of the entire display surface. phenomenon. In order to suppress this condensing effect to prevent whitening, the ratio of the surface of the fine uneven surface having an inclination angle of 5 or less is preferably higher, preferably 97% or more, and particularly preferably 99% or more.

Here, the "inclination angle of the fine uneven surface" in the present invention means that, at any point P on the surface of the anti-glare film 1, with respect to the main normal direction 5 of the anti-glare film, referring to FIG. 2, The angle (surface tilt angle) 局部 formed by the local normal 6 after weighting the concave and convex portions. The inclination angle of the fine uneven surface can be obtained from the three-dimensional information of the surface shape measured by a device such as a confocal microscope, an interference microscope, or an atomic force microscope (AFM), similarly to the elevation.

Fig. 7 is a schematic view for explaining a method of measuring the inclination angle of the fine uneven surface. When the specific tilt angle determining method is described, as shown in Fig. 7, first, the eye point A on the virtual plane FGHI indicated by the broken line is determined, and in the vicinity of the eye point A on the x-axis passing through the point, Point A is almost symmetrical with points B and D, and points C and E which are almost symmetrical with respect to point A near the point of view A on the y-axis passing through point A, and are determined to correspond to points B and C. The points Q, R, S, and T on the anti-glare film surface of D, E. In Fig. 7, the orthogonal coordinates in the plane of the anti-glare film are indicated by (x, y), and the coordinates in the thickness direction of the anti-glare film are indicated by z. The plane FGHI is a line parallel to the x-axis passing through the point C on the y-axis, and a line parallel to the x-axis passing through the point E on the y-axis, respectively, passing through the point B on the x-axis parallel to the y-axis The straight line and the line formed by the straight line parallel to the y-axis of the point D on the x-axis and the intersections F, G, H, and I. In addition, in Fig. 7, the position of the actual anti-glare film surface is drawn upward with respect to the plane FGHI, but of course, the actual anti-glare film surface can be made different depending on the position of the eye point A. Position above or below the plane FGHI.

Regarding the tilt angle, the point P corresponding to the actual anti-glare film surface corresponding to the eye point A and the point corresponding to the point near the eye point A can be obtained from the three-dimensional information of the measured surface shape. 4 points B, C, D, E The four planes of the polygon formed by the total of five points Q, R, S, and T on the anti-glare film surface, that is, four triangles PQR, PRS, PST, PTQ The average normal vector obtained by averaging the normal vectors 6a, 6b, 6c, and 6d (the average normal vector is synonymous with the local normal 6 which is weighted by the unevenness shown in Fig. 2) Obtained from the polar angle of the main normal direction of the glare film. After obtaining the tilt angle for each measurement point, the histogram is calculated.

Fig. 8 is a graph showing an example of a histogram of the oblique angle distribution of the fine uneven surface of the antiglare layer provided in the antiglare film. In the graph shown in Fig. 8, the horizontal axis is an oblique angle and is divided by a scale of 0.5°. For example, the leftmost straight column represents a distribution of a set of ranges in which the tilt angle is in the range of 0 to 0.5, and then the angle is increased by 0.5° each time as it moves to the right. In Fig. 8, the lower limit value of the value of each of the two scales on the horizontal axis is shown. For example, the portion of "1" on the horizontal axis indicates the distribution of the set of the range in which the inclination angle is in the range of 1 to 1.5. Further, the vertical axis represents the distribution of the inclination angles and is a value of 1 (100%) in total. In this example, the ratio of the surface having an inclination angle of 5 or less is approximately 100%.

In order to produce an anti-glare film in which the fine uneven surface of the anti-glare layer contains 95% or more of a surface having an inclination angle of 5 or less, it is preferable to use a pattern to form a mold having a concave-convex surface, and the uneven surface of the mold is used. A method of transferring the surface of the resin layer formed on the substrate film (embossing method). In the embossing method as described above, the inclination angle of the fine uneven surface of the antiglare layer is determined by the manufacturing conditions of the mold having the uneven surface. Specifically, it can be controlled by changing the etching amount of the etching process in the manufacturing method of the mold mentioned later. In other words, by reducing the amount of etching in the first etching step, the height difference of the first surface unevenness formed can be reduced, and the ratio of the surface having the inclination angle of 5 or less can be increased. In order to obtain an anti-glare film having a fine uneven surface containing 95% or more of the surface having an inclination angle of 5 or less, the etching amount in the first etching step is preferably 2 to 8 μm. When the etching amount is less than 2 μm, the metal surface hardly forms an uneven shape and becomes a nearly flat mold, and the anti-glare film produced by using the mold cannot exhibit sufficient anti-glare property. Further, when the etching amount exceeds 8 μm, the height difference of the uneven shape formed on the metal surface increases, and the surface having an inclination angle of 5 or less may be less than 95%. The anti-glare film produced by using this mold has doubts about whitening.

Further, the inclination angle of the fine uneven surface of the antiglare layer can be controlled by the etching amount in the second etching step. By increasing the etching amount in the second etching step, it is possible to effectively passivate the portion where the surface of the first surface uneven shape is steeply inclined, and increase the ratio of the surface having the inclination angle of 5 or less. In order to obtain an anti-glare film having a fine uneven surface containing 95% or more of the surface having an inclination angle of 5 or less, the etching amount in the second etching step is preferably in the range of 4 to 20 μm. When the etching amount is small, the effect of passivating the surface shape of the unevenness obtained by the first etching step is insufficient, and the optical characteristics of the anti-glare film obtained by transferring the uneven shape are not good. On the other hand, when the etching amount is too large, the uneven shape almost disappears and becomes a nearly flat mold, so that the anti-glare property cannot be exhibited.

In the present invention, the antiglare layer may be composed of a cured product of a curable resin such as a photocurable resin or a thermoplastic resin, and is preferably composed of a cured product of a photocurable resin. In the antiglare layer, fine particles having a refractive index different from that of the cured resin or the thermoplastic resin may be dispersed. By dispersing the particles, the flare is more effectively suppressed.

When the fine particles are dispersed in the antiglare layer, the average particle diameter of the fine particles is preferably 5 μm or more, and particularly preferably 6 μm or more. Further, the average particle diameter of the fine particles may be about 10 μm or less, preferably 8 μm or less. When the average particle diameter is less than 5 μm, the scattered light intensity on the wide-angle side caused by the fine particles rises, and when applied to an image display device, the contrast tends to be lowered.

Further, the refractive index n _r and the refractive index n _b of the cured curable resin or a thermoplastic resin particle ratio n _b / n _r, is preferably 0.93 or more 1.01 or more 0.98 or less 1.04 or less, particularly preferably 0.97 or more and 0.98 or less or 1.01 or more and 1.03 or less. When the refractive index ratio n _b /n _{r is} less than 0.93 or higher than 1.04, the reflectance of the hardened resin or the interface between the thermoplastic resin and the fine particles is increased, and as a result, the backscattering is increased, and the total light transmittance is obtained. Reduce the tendency. A decrease in the total light transmittance increases the haze of the anti-glare film, and a contrast reduction occurs when applied to an image display device. Further, when the refractive index ratio n _b /n _r exceeds 0.98 and does not reach 1.01, since the internal scattering effect formed by the microparticles is small, in order to impart predetermined scattering characteristics to the antiglare layer to obtain a speckle caused by the microparticles When suppressing the effect, it may be necessary to increase the amount of addition of particles.

The content of the fine particles is usually 50 parts by weight or less, preferably 40 parts by weight or less, based on 100 parts by weight of the curable resin or the thermoplastic resin. Further, the content of the fine particles is preferably 10 parts by weight or more, and particularly preferably 15 parts by weight or more. When the content of the fine particles is less than 10 parts by weight, the effect of suppressing the speckle formation by the fine particles may be insufficient.

The material constituting the fine particles preferably satisfies the above preferred refractive index ratio. As described later, in the present invention, the UV embossing method is preferably used for the formation of the antiglare layer, and the ultraviolet curable resin is preferably used in the UV embossing method. In this case, since the cured product of the ultraviolet curable resin exhibits a refractive index of about 1.50, the antiglare film can be appropriately selected as the fine particles from the refractive index of 1.40 to 1.60. The fine particles are preferably those which are resin beads and which are almost spherical. Examples of such preferred resin beads are as disclosed below.

Melamine beads (refractive index 1.57), polymethylmethacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50 to 1.59), polycarbonate beads ( Refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), polydecane resin beads (refractive index 1.46), etc. .

(substrate film)

The base film used in the anti-glare film of the present invention is preferably composed of an acrylic resin which is excellent in transparency, moisture resistance, weather resistance, and mechanical strength, or an acrylic resin. Here, the acrylic resin in the present invention means a material obtained by mixing a methacrylic resin and an additive which is added as necessary, and melt-blending.

The methacrylic resin is a polymer mainly composed of methacrylate. The methacrylic resin may be a monomer of methacrylate or a copolymer of methacrylate and other methacrylate or acrylate. The methacrylate may, for example, be an alkyl methacrylate such as methyl methacrylate, ethyl methacrylate or butyl methacrylate, and the alkyl group usually has a carbon number of about 1 to 4. Further, an acrylate copolymerizable with a methacrylate, preferably an alkyl acrylate, may, for example, be methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate. The carbon number is usually about 1 to 8. Further, in the copolymer, an aromatic vinyl compound such as styrene having a compound having at least one polymerizable carbon-carbon double bond in the molecule or an ethylene cyanide compound such as acrylonitrile may be used.

The acrylic resin preferably contains acrylic rubber particles from the viewpoint of impact resistance and film forming properties of the base film. The amount of the acrylic rubber particles which may be contained in the acrylic resin is preferably 5% by weight or more, and particularly preferably 10% by weight or more. The upper limit of the amount of the acrylic rubber particles is not limited, but when the amount of the acrylic rubber particles is too large, the surface hardness of the base film is lowered, and when the surface treatment is applied to the base film, it is relative to the surface treatment agent. The solvent resistance of the organic solvent is lowered. Therefore, the amount of the acrylic rubber particles which may be contained in the acrylic resin is preferably 80% by weight or less, and particularly preferably 60% by weight or less.

The acrylic rubber particles are particles in which an elastic polymer mainly composed of acrylate is used as an essential component, and may be a single layer structure consisting essentially of only the elastic polymer, or the elastic polymer may be composed of 1 Multilayer construction of layers. Specifically, the elastic polymer is preferably a crosslinked elastic copolymer obtained by polymerization of the following monomer composition, which is composed of: alkyl acrylate 50 to 99.99% by weight, at least one type It can be composed of 0 to 49.9% by weight of the other vinyl monomer copolymerized with the alkyl acrylate, and 0.1 to 10% by weight of the copolymerizable crosslinking monomer.

The alkyl acrylate which forms the elastic polymer may, for example, be methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate. The alkyl group usually has a carbon number of about 1 to 8. Further, examples of the other vinyl monomer copolymerizable with the above alkyl acrylate include a compound having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methyl methacrylate is exemplified. A methacrylate, an aromatic vinyl compound such as styrene, an ethylene cyanide compound such as acrylonitrile, or the like. Further, the above-mentioned copolymerizable crosslinkable monomer may, for example, be a compound having at least two polymerizable carbon-carbon double bonds in the molecule, and specifically, for example, di(methyl) (meth) acrylates of polyols of ethylene glycol acrylate and butylene glycol di(meth)acrylate, such as allyl (meth) acrylate and methyl allyl (meth) acrylate (A) Alkenyl ester of acrylic acid, divinylbenzene, and the like. In the present specification, the term "(meth)acrylate" means methacrylate or acrylate, and the term "(meth)acrylic acid" means methacrylic acid or acrylic acid.

The acrylic resin may contain a usual additive in addition to the above acrylic rubber particles, and examples thereof include an ultraviolet absorber, an organic dye, a pigment, an inorganic dye, an antioxidant, an antistatic agent, and a surfactant. In view of improving weather resistance, an ultraviolet absorber can be preferably used. Examples of the ultraviolet absorber include, for example, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2- Phenol], 2-(5-methyl-2-hydroxyphenyl)-2H-benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl Phenyl-2H-benzotriazole, 2-(3,5-di-tertiary butyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(3-tert-butyl-5 -methyl-2-hydroxyphenyl)-5-chloro-2H-benzotriazole, 2-(3,5-di-tertiarybutyl-2-hydroxyphenyl)-5-chloro-2H-benzene And triazole, 2-(3,5-di-tri-pentyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(2'-hydroxy-5'-trioctylphenyl) -2H-benzotriazole benzotriazole-based UV absorber; such as 2-hydroxy-4-methoxydiphenyl ketone, 2-hydroxy-4-octyloxydiphenyl ketone, 2,4-dihydroxyl Diphenyl ketone, 2-hydroxy-4-methoxy-4'-chlorodiphenyl ketone, 2,2'-dihydroxy-4-methoxydiphenyl ketone, 2,2'-dihydroxy-4, 2-hydroxydiphenyl ketone ultraviolet absorber of 4'-dimethoxydiphenyl ketone; such as butyl phenyl phthalate, phenyl phenyl phenyl phenyl acrylate In addition, two or more of these may be used as necessary. When the ultraviolet absorber is contained in the acrylic resin, the amount is usually 0.1% by weight or more, preferably 0.3% by weight or more, and more preferably 2% by weight or less.

The thickness of the base film is preferably 20 μm or more from the viewpoint of mechanical strength and handleability, and from the viewpoint of preventing curling of the film during formation of the antiglare layer, and further, the thickness and cost of the image display device are reduced. From the viewpoint, it is preferably 100 μm or less. The thickness of the base film is preferably 40 μm or more and 80 μm or less.

As a method of producing the base film used in the antiglare film of the present invention, for example, various methods generally known, such as melt extrusion molding, can be used. In view of the fact that a film having a good surface property can be obtained, it is preferred to carry out melt extrusion molding from a T die, and at least one side of the obtained molten film is brought into contact with a roll surface or a belt surface. The method of film making. In particular, from the viewpoint of improving the surface smoothness and surface glossiness of the base film, it is preferred to form a film by contacting both surfaces of the molten film obtained by the melt extrusion molding on the surface of the roll or the surface of the belt. In the roll or belt used at this time, the surface of the roll or the surface of the belt which is in contact with the molten film of the acrylic resin is preferably a mirror surface in order to impart smoothness to the surface of the base film.

The base film may be composed of a multilayer structure, and the multilayer structure may be a laminated structure including a layer of acrylic rubber particles and a layer containing no acrylic rubber particles. The substrate film having a multilayer structure can be suitably produced, for example, by multilayer melt extrusion molding using a feed block or a multi-manifold mold. By forming the base film into a multilayer structure, the opposite characteristics can be imparted to the base film. For example, the base layer having a layer containing acrylic rubber particles and having a multilayer structure of a layer containing no acrylic rubber particles on the outermost surface of the surface layer can have high impact resistance by containing an intermediate layer of acrylic rubber particles. And has a high surface hardness by not containing the surface layer of the acrylic rubber particles.

Further, the base film used in the antiglare film of the present invention may be subjected to a stretching treatment on the film formed of the acrylic resin obtained above. By the stretching treatment, stronger impact resistance can be imparted. The stretching method may be any method, and is not particularly limited, and examples thereof include a method of applying a heat setting treatment after stretching in a transverse direction by a tenter at a temperature equal to or higher than a glass transition temperature, or a temperature higher than a glass transition temperature. After the longitudinal stretching by a tenter, a heat setting treatment is applied, and then the transverse stretching is performed and then subjected to a heat setting treatment.

<Method for Producing Anti-Glare Film>

The antiglare film of the present invention described above is preferably produced by a method comprising the following steps (A) and (B).

(A) a step of producing a mold having a concave-convex surface based on a pattern showing an energy spectrum having a maximum value in a range of a spatial frequency of more than 0 μm ^-1 and not more than 0.04 μm ^-1 ;

(B) The step of transferring the uneven surface of the mold to the surface of the resin layer formed of the curable resin such as a photocurable resin or a thermoplastic resin, which is formed on the base film.

By using a pattern having an energy spectrum having a maximum value in a range of a spatial frequency of more than 0 μm ^-1 and not more than 0.04 μm ^-1 , it is possible to accurately form a fine uneven surface having the above-described specific spatial frequency distribution. Further, by producing a mold having a concave-convex surface according to the pattern, and transferring the uneven surface of the mold to the surface of the resin layer formed on the base film (embossing method), accuracy and reproducibility can be achieved. An anti-glare layer having a fine uneven surface is produced satisfactorily. Here, the "pattern" generally means a second-order tone (for example, binarized image data of white and black) which is used by a computer for forming a fine uneven surface of an anti-glare film. Or image data composed of gradations above the 3rd order, but may also contain data (array, etc.) that can be converted into the image data in a single meaning. It can be converted into data of image data in a single sense, such as coordinates of each pixel and data of only the tone.

The energy spectrum of the pattern used in the above step (A), for example, in the case of image data, can be obtained by converting the image data into a second-order binary image data by a two-dimensional function g(x, y) to represent the tone of the image data, and the resulting two-dimensional function g(x, y) is subjected to discrete Fourier transform to calculate a two-dimensional function G(f _x , f _y ), and then the obtained two-dimensional function G(f _x , f _y ) is obtained by squaring. Here, x and y represent orthogonal coordinates in the image data plane, and f _x and f _y represent the spatial frequency in the x direction and the spatial frequency in the y direction, respectively.

The same as the energy spectrum of the elevation of the surface of the fine concave and convex surface, the two-dimensional function g(x, y) of the tone is generally obtained as a discrete function when the energy spectrum of the pattern is obtained. At this time, the energy spectrum can be calculated by discrete Fourier transform, similar to the energy spectrum of the elevation of the surface of the fine uneven surface. Specifically, the discrete function G(f _x , f _y ) is calculated by the discrete Fourier transform defined by the equation (5), and then the obtained discrete function G(f _x , f _y ) is squared The energy spectrum G ² (f _x , f _y ) is taken. Here, π in the formula (5) is a pi, and i is an imaginary unit. Further, M is the number of pixels in the x direction, N is the number of pixels in the y direction, 1 is an integer of -M/2 or more and M/2 or less, and m is an integer of -N/2 or more and N/2 or less. Further, Δf _x and Δf _y are spatial frequency intervals in the x direction and the y direction, respectively, and are defined by the equations (6) and (7), respectively. Δx and Δy in the equations (6) and (7) are horizontal decomposition energies in the x-axis direction and the y-axis direction, respectively. When the pattern is image data, Δx and Δy are equal to the length of the x-axis direction of one pixel and the length of the y-axis direction, respectively. That is, when the pattern is made into image data of 6400 dpi, Δx = Δy = 4 μm, and when the pattern is made into image data of 12800 dpi, Δx = Δy = 2 μm.

Fig. 9 is a view showing a part of image data which can be used to fabricate the pattern used for the anti-glare film of the present invention, and is represented by a two-dimensional discrete function g(x, y) of a tone. The image data of the pattern shown in Fig. 9 was 2 mm × 2 mm and was produced at 12,800 dpi.

Figure 10 white and black lines in order to indicate a degree of order as shown in FIG 9, the two-dimensional transfer function g (x, y) for discrete Fourier transform of the resulting spectrum ^{_{G 2 (f x, f y}} ) of Figure. Since the pattern shown in Fig. 9 is randomly arranged, the energy spectrum G ² (f _x , f _y ) is symmetrical about the origin as shown in Fig. 10. Therefore, the spatial frequency of the maximum value of the display energy spectrum G ² (f _x , f _y ) of the pattern can be obtained from the profile passing through the origin of the energy spectrum. Fig. 11 is a view showing a cross section of f _x =0 in the energy spectrum G ² (f _x , f _y ) shown in Fig. 10. Known from the figure, the pattern shown in FIG. 9 in the first spatial frequency 0.045μm ^-1 has a maximum value, but does not have a maximum value greater than 0μm ^-1 and is 0.04μm ^-1 or less.

When the energy spectrum G ² (f _x , f _y ) of the pattern for producing the anti-glare film has a maximum value in a spatial frequency range which is larger than 0 μm ⁻¹ and is 0.04 μm ⁻¹ or less, the obtained anti-glare The fine uneven surface of the film does not exhibit the above-described specific spatial frequency distribution, so that the elimination of the flare and the sufficient anti-glare property cannot be achieved at the same time.

The energy spectrum G ² (f _x , f _y ) has a pattern having no maximum value in a spatial frequency range larger than 0 μm ⁻¹ and less than 0.04 μm ⁻¹ , for example, the pattern shown in FIG. 9 can be A plurality of points are randomly and uniformly arranged to be produced. The dot diameters that are randomly arranged may be one or plural. Further, in a pattern in which a plurality of dots are randomly arranged, the spectral line shows a first maximum value at a spatial frequency of the reciprocal of the average distance between the points (the spatial frequency is smaller than the minimum spatial frequency of 0 μm ^-1 The maximum value). Therefore, in order to produce a pattern having an energy spectrum which is larger than 0 μm ^-1 and has a maximum value in a spatial frequency range of 0.04 μm ^-1 or less, it is only necessary to form a pattern so that the average distance between dots is less than 25 μm. can. Further, in order to space the antiglare film of the frequency spectrum of the finely uneven surface elevation of ^-1 0.1μm H ₃ ² 0.04μm spatial frequency spectrum of the ^level-1 ratio of H _{² 2} H ₃ ² / H _{When 2} ^{2 is} set to 0.1 or less, the energy spectrum of the pattern is preferably a maximum value in a range in which the spatial frequency is more than 0.04 μm ^-1 and less than 0.1 μm ^-1 . Such a pattern can be obtained by making the average distance between the dots larger than 10 μm and less than 25 μm.

Further, a pattern obtained by randomly arranging a pattern created by such a plurality of dots to pass a high-pass filter for removing a low spatial frequency component below a specific spatial frequency may be used. Furthermore, it is also possible to use a pattern created by randomly arranging such a plurality of dots to pass band-pass filtering for removing low spatial frequency components below a specific spatial frequency and high spatial frequency components above a specific spatial frequency. The pattern of the device.

As shown in Fig. 11, the energy spectrum of the pattern created by a plurality of dots is randomly arranged, and the maximum value depending on the point diameter of the arranged point and the average distance between the points is indicated, by which the pattern is passed. The aforementioned high pass filter or the aforementioned band pass filter can remove unnecessary components. Since the energy spectrum of the pattern passing through the high-pass filter or the band-pass filter is removed by the filter, it does not have a maximum value in a range in which the spatial frequency is larger than 0 μm ^-1 and 0.04 μm ^-1 or less. Further, it is possible to more efficiently produce a pattern having a maximum value in a range of a spatial frequency of more than 0.04 μm ^-1 and less than 0.1 μm ^-1 . Here, when the high-pass filter is used, in order to remove the maximum value in the range where the spatial frequency is larger than 0 μm ^-1 and 0.04 μm ^-1 or less, the upper limit spatial frequency of the removed low spatial frequency component is preferably 0.04 μm. ^-1 or less. Further, when the aforementioned band pass filter is used, in order to remove a maximum value in a range in which the spatial frequency is larger than 0 μm ^-1 and 0.04 μm ^-1 or less, and the spatial frequency is larger than 0.04 μm ^-1 and less than 0.1 μm ^-1 The upper limit spatial frequency of the low spatial frequency component to be removed is preferably 0.04 μm ^-1 or less, and the lower spatial frequency of the removed high spatial frequency component is preferably 0.08 μm ^-1 or more.

When a pattern is created by a method such as a high-pass filter or a band-pass filter, the pattern before the filter can be used to determine the shading by a random number generated by a random number or a computer, and has a random brightness. The pattern of distribution.

The details of the method of producing a mold according to the pattern obtained in the above manner will be described in detail later.

The above step (B) is a step of forming an antiglare layer having a fine uneven surface on the base film by an embossing method. The embossing method can be exemplified by a UV embossing method using a photocurable resin and a hot embossing method using a thermoplastic resin. Among them, a UV embossing method is preferred from the viewpoint of productivity. In the UV embossing method, the photocurable resin layer is formed on the surface of the base film, and the photocurable resin layer is pressed against the uneven surface of the mold to be cured, whereby the uneven surface of the mold is transferred to A method of photocurable resin layer. More specifically, the coating liquid containing the photocurable resin is applied onto the base film, and the coated photocurable resin is adhered to the uneven surface of the mold, and is irradiated from the substrate film side. The light-curable resin is cured by light such as ultraviolet rays, and then the base film on which the cured photo-curable resin layer is formed is peeled off from the mold, whereby the uneven shape of the mold can be obtained and transferred to the cured state. An anti-glare film of a photo-curable resin layer (anti-glare layer).

The photocurable resin in the case of using the UV embossing method is preferably an ultraviolet curable resin which is cured by ultraviolet rays, or an optically curable resin which is appropriately selected may be combined with an ultraviolet curable resin, and can be used by A resin that has a wavelength longer than that of ultraviolet light and hardens it. The type of the ultraviolet curable resin is not particularly limited, and a commercially available suitable product can be used. A preferred example of the ultraviolet curable resin is one or more selected from the group consisting of polyfunctional acrylates such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate, and Irgacure 907 (manufactured by Chiba Specialty Chemicals Co., Ltd.), Irgacure. A resin composition of a photopolymerization initiator such as 184 (manufactured by Chiba Specialty Chemicals Co., Ltd.) or Lucirin TPO (manufactured by BASF Corporation). The coating liquid can be prepared by adding fine particles, a solvent, or the like to the ultraviolet curable resin as necessary.

<Method for Producing Mold for Manufacturing Anti-Glare Film>

Hereinafter, a method of producing a mold used in the production of the antiglare film of the present invention will be described. The method for producing a mold used in the production of the anti-glare film of the present invention is not particularly limited as long as it can obtain a specific surface shape obtained by the above-described pattern, but is excellent in accuracy and reproducibility. The fine uneven surface preferably contains [1] the first plating step, the [2] polishing step, the [3] photosensitive resin film forming step, the [4] exposure step, the [5] developing step, and [6]. The first etching step, the [7] photosensitive resin film peeling step, and the [8] second plating step. Fig. 12 is a view schematically showing a preferred example of the first half of the method for manufacturing a mold. Fig. 13 is a view schematically showing a preferred example of the latter half of the method of manufacturing the mold. In Figs. 12 and 13, the cross section of the mold in each step is schematically shown. Hereinafter, each of the above steps will be described in detail with reference to FIGS. 12 and 13.

[1] First plating process

In this step, the surface of the substrate used in the mold is subjected to copper plating or nickel plating. As described above, by applying copper plating or nickel plating to the surface of the substrate for a mold, the adhesion and gloss of chrome plating in the subsequent second plating step can be improved. In this case, since copper plating or nickel plating has high coating property and strong smoothing effect, it is possible to form a flat and shiny surface by embedding fine irregularities or cavities of the substrate for a mold. By the characteristics of such copper plating or nickel plating, even if chrome plating is applied in the second plating step to be described later, chrome plating which is regarded as causing minute irregularities or cavities existing on the substrate can be eliminated. The surface is roughened, and since the coating property of copper plating or nickel plating is high, the generation of fine cracks can be reduced.

The copper or nickel used in the first plating step may be a copper-based alloy or a nickel-based alloy, in addition to a pure metal. Therefore, the term "copper" in the present specification includes copper. And the meaning of copper alloy, in addition, "nickel" contains the meaning of nickel and nickel alloy. Copper plating and nickel plating can be performed by electrolytic plating or electroless plating, respectively, and electrolytic plating is generally used.

When copper plating or nickel plating is applied, when the plating layer is too thin, the influence of the underlying surface cannot be completely excluded, so the thickness is preferably 50 μm or more. The upper limit of the thickness of the plating layer is not limited, and it is generally about 500 μm in terms of cost and the like.

The metal material constituting the base material for the mold is exemplified by aluminum, iron, and the like from the viewpoint of cost. In addition, in terms of handling convenience, it is particularly preferred to be lightweight aluminum. The aluminum or iron referred to herein may be an alloy mainly composed of aluminum or iron, in addition to pure metals.

Further, the shape of the substrate for a mold may be any shape as conventionally used in the art, and may be a cylindrical or cylindrical roll in addition to a flat plate shape. When a mold is produced using a roll-shaped base material, there is an advantage that an anti-glare film can be produced in a continuous roll shape.

[2] Grinding process

In the subsequent polishing step, the surface of the substrate which has been subjected to copper plating or nickel plating in the first plating step is polished. Preferably, the surface of the substrate is ground to a state close to the mirror surface through this process. Since this is a metal plate or a metal roll which is a base material, in order to achieve a desired precision, machining by cutting or grinding is often performed, and processing marks remain on the surface of the substrate, even if copper plating or nickel plating is applied. In the state, these processing marks may remain, or in the plated state, the surface may not be completely smooth. In other words, even if the surface of the deep processing mark remains as described later, the unevenness of the processing mark or the like may be deeper than the unevenness formed after the respective steps, and the possibility of residual processing marks may be affected. When such a mold is used to manufacture an anti-glare film, it may have an unpredictable effect on optical characteristics. In Fig. 12(a), a flat substrate 7 for a mold is schematically shown, and in the first plating step, the surface thereof is plated with copper or nickel (the copper plating or nickel plating formed in the step) The layer is not shown) and then has the state of the mirror-polished surface 8 by the grinding process.

The method of polishing the surface of the substrate to which copper plating or nickel plating is applied is not particularly limited, and any of a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method can be used. The mechanical polishing method may, for example, be a super processing method, a lapping method, a fluid polishing method, a buffing method, or the like. Further, the surface of the substrate for the mold can be mirror-finished by mirror-cutting using a cutting tool. The material or shape of the cutting tool to be used at this time is not particularly limited, and a superhard knife, a CBN knife, a ceramic knife, a diamond knife, or the like can be used, and a diamond knife is preferably used from the viewpoint of processing accuracy.

The surface roughness after polishing is preferably 0.1 μm or less, and particularly preferably 0.05 μm or less, in accordance with the center line average roughness Ra of JIS B 0601. When the center line average roughness Ra after grinding is more than 0.1 μm, the influence of the surface roughness after polishing may remain on the uneven shape of the finally formed mold surface. Further, the lower limit of the center line average roughness Ra is not particularly limited, and may be appropriately determined in consideration of processing time and processing cost.

[3] Photosensitive resin film forming process

In the subsequent photosensitive resin film forming step, a solution in which a photosensitive resin is dissolved in a solvent is applied to the polished surface 8 of the substrate 7 for a mold which is mirror-polished by the polishing step, and Heating and drying are performed to form a photosensitive resin film. In the Fig. 12(b), the state in which the photosensitive resin film 9 is formed on the polished surface 8 of the substrate 7 for a mold is schematically shown.

As the photosensitive resin, a conventionally known photosensitive resin can be used. For example, as a negative photosensitive resin having a photohardenable property, it can be used for a monomer or prepolymer having an acrylate or methacrylic group in a molecule, a diazide and a diene rubber. Mixture, polyethylene cinnamate-based compound, and the like. In addition, as the positive photosensitive resin having a property of eluting the photosensitive portion by development and leaving only the non-photosensitive portion, a phenol resin-based or phenol resin-based resin or the like can be used. Further, various additives such as a sensitizer, a development accelerator, an adhesion modifier, and a coatability modifier may be blended in the photosensitive resin as necessary.

When such a photosensitive resin is applied to the polished surface 8 of the substrate 7 for a mold, it is preferably diluted with an appropriate solvent to form a coating film. A cellosolve solvent, a propylene glycol solvent, an ester solvent, an alcohol solvent, a ketone solvent, a highly polar solvent, or the like can be used as the solvent.

As a method of applying the photosensitive resin solution, a concave-convex coating, a jet coating, a dip coating, a spin coating, a roll coating, a wire bar coating, an air knife coating, a knife coating, a curtain coating, or the like can be used. A generally known method. The thickness of the coating film is preferably in the range of 1 to 6 μm after drying.

[4] Exposure process

In the subsequent exposure step, the photosensitive spectrum formed in the photosensitive resin film forming step is exposed to a pattern having a maximum value in a spatial frequency range of more than 0 μm ^-1 and 0.04 μm ^-1 or less. On the resin film 9. The light source used in the exposure step can be appropriately selected in accordance with the photosensitivity and/or sensitivity of the photosensitive resin. For example, g-ray (wavelength: 436 nm) of a high-pressure mercury lamp or h-ray (wavelength: 405 nm) of a high-pressure mercury lamp can be used. High-pressure mercury lamp i-ray (wavelength: 365 nm), semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), YAG laser (wavelength: 1064 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm), F2 excimer laser (wavelength: 157 nm), and the like.

In order to accurately form the surface uneven shape of the mold and the surface uneven shape of the antiglare layer, it is preferable to expose the pattern to the photosensitive resin film in a state of being precisely controlled in the exposure step, specifically, A pattern is created in the computer as image data, and based on the image data, the pattern is drawn on the photosensitive resin film by laser light emitted from a computer-controlled laser head. For laser drawing, a laser drawing device for printing plate production can be used. Laser Stream FX (manufactured by Think Laboratory) or the like can be cited as the laser drawing device.

In Fig. 12(c), a state in which the pattern is exposed to the photosensitive resin film 9 is schematically shown. When the photosensitive resin film is formed of a negative photosensitive resin, the exposed region 10 is subjected to a crosslinking reaction of the resin by exposure, so that the solubility with respect to the developer described later is lowered. Therefore, the unexposed area 11 in the developing process is dissolved by the developer, and only the exposed region 10 remains on the surface of the substrate to form a mask. On the other hand, when the photosensitive resin film is formed by the positive photosensitive resin, the exposed region 10 is cut by the exposure of the resin to increase the solubility with respect to the developer described later. Therefore, the exposed region 10 in the developing step is dissolved by the developer, and only the unexposed region 11 remains on the surface of the substrate to form a mask.

[5] Development process

In the subsequent development process, when a negative photosensitive resin is used as the photosensitive resin film 9, the unexposed region 11 is dissolved by the developer, and only the exposed region 10 remains on the substrate for the mold, and It acts as a mask in the subsequent first etching step. On the other hand, when a positive photosensitive resin is used as the photosensitive resin film 9, only the exposed region 10 is dissolved by the developer, and the unexposed region 11 remains on the substrate for the mold, and is continued. In the first etching step, it acts as a mask.

The developer used in the development step can be used as known. Examples thereof include inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, and aqueous ammonia; first amines such as ethylamine and n-propylamine; and diethylamine and di-n-butyl a second amine such as an amine; a third amine such as triethylamine or methyldiethylamine; an alcohol amine such as dimethylethanolamine or triethanolamine; tetramethylammonium hydroxide or tetraethylammonium hydroxide And a quaternary ammonium salt such as trimethylhydroxyethylammonium hydroxide; an aqueous alkaline solution such as a cyclic amine such as pyrrole or piperidine; and an organic solvent such as xylene or toluene.

The developing method in the developing step is not particularly limited, and methods such as immersion development, spray development, magnetic brush development, and ultrasonic development can be used.

In the figure (d) of FIG. 12, a state in which a development process is performed using a negative photosensitive resin as the photosensitive resin film 9 is schematically shown. In Fig. 12(c), the unexposed region 11 is dissolved by the developer, and only the exposed region 10 remains on the surface of the substrate to become the mask 12. In the Fig. 12(e), a state in which development processing is performed using a positive photosensitive resin as the photosensitive resin film 9 is schematically shown. In Fig. 12(c), the exposed region 10 is dissolved by the developer, and only the unexposed region 11 remains on the surface of the substrate to become the mask 12.

[6] First etching process

In the subsequent first etching step, the photosensitive resin film remaining on the surface of the substrate for a mold is used as a mask after the development step, and the substrate for the mold without the mask is mainly etched. Concavities and convexities are formed on the polished plating surface. In Fig. 13(a), the state in which the substrate 7 for a mold without the mask 13 is mainly etched by the first etching step is schematically shown. The substrate 7 for the mold at the lower portion of the mask 12 is not etched from the surface of the substrate for the mold, but is etched from the unmasked portion 13 as the etching progresses. Therefore, in the vicinity of the boundary between the mask 12 and the unmasked portion 13, the substrate 7 for the mold at the lower portion of the mask 12 is also etched. Hereinafter, in the vicinity of the boundary between the mask 12 and the unmasked portion 13, the substrate 7 for the mold at the lower portion of the mask 12 is also etched, which is called side etching.

The etching treatment in the first etching step is generally performed by using a ferric chloride (FeCl ₃ ) solution, a copper chloride (CuCl ₂ ) solution, an alkali etching solution (Cu(NH ₃ ) ₄ Cl ₂ ), or the like by using a metal surface. Corrosion is carried out, but a strong acid such as hydrochloric acid or sulfuric acid may be used, or a reverse electrolytic etching may be performed by applying a potential opposite to that at the time of electrolytic plating. The concave shape formed on the substrate for a mold during the etching treatment differs depending on the type of the underlying metal, the type of the photosensitive resin film, and the etching method, but the etching amount is 10 μm or less. The etching is performed substantially equilaterally from the surface of the metal that is in contact with the etching liquid. The amount of etching referred to herein means the thickness of the substrate removed by etching.

The etching amount in the first etching step is preferably from 1 to 50 μm, particularly preferably from 2 to 10 μm. When the etching amount is less than 1 μm, the metal surface hardly forms an uneven shape and becomes a nearly flat mold, so that the anti-glare property cannot be exhibited. Further, when the etching amount exceeds 50 μm, the difference in the height of the uneven shape formed on the metal surface increases, and the image display device using the anti-glare film produced by the obtained mold may cause whitening. In order to obtain an anti-glare film having a fine uneven surface containing 95% or more of the surface having an inclination angle of 5 or less, the etching amount in the first etching step is particularly preferably 2 to 8 μm. The etching treatment in the first etching step can be performed by one etching treatment or by dividing the etching treatment into two or more. When the etching treatment is carried out in two or more steps, the total etching amount of the etching treatment of two or more times is preferably within the above range.

[7] Photosensitive resin film peeling process

In the subsequent photosensitive resin film peeling step, the photosensitive resin film remaining as a mask in the first etching step is completely dissolved and removed. In the photosensitive resin film peeling step, a photosensitive resin film is dissolved using a peeling liquid. The peeling liquid can be used in the same manner as the above-mentioned developing solution, and by changing the pH, temperature, concentration, immersion time, etc., when a negative photosensitive resin is used, the photosensitive resin film of the exposed portion can be completely dissolved, and when used, In the case of the photosensitive resin, the photosensitive resin film in the non-exposed portion can be completely dissolved and removed. The peeling method in the photosensitive resin film peeling step is not particularly limited, and methods such as immersion development, spray development, magnetic brush development, and ultrasonic development can be used.

In the first step (b), the photosensitive resin film peeling step is used to completely remove the photosensitive resin film used as the mask 12 in the first etching step. The first surface uneven shape 15 can be formed on the surface of the substrate for a mold by etching using the mask 12 formed of the photosensitive resin film.

[8] 2nd plating process

Next, chrome plating is applied to the formed uneven surface (first surface uneven shape 15) to passivate the uneven shape of the surface. In Fig. 13(c), the first surface uneven shape 15 formed by the etching treatment in the first etching step is formed to form the chrome-plated layer 16 so that the unevenness is more passivated than the first surface uneven shape 15 The state of the surface (chrome surface 17).

The chrome plating is preferably a chrome plating which is glossy on a surface of a flat plate or a roll, has a high hardness, a small coefficient of friction, and imparts good mold release property. The chrome plating is not particularly limited, but it is preferably chrome plating which exhibits good gloss such as gloss chrome plating or decorative chrome plating. The chrome plating is generally carried out by electrolysis, and the plating bath may use an aqueous solution containing anhydrous chromic acid (CrO ₃ ) and a small amount of sulfuric acid. The thickness of the chrome plating can be controlled by adjusting the current density and the electrolysis time.

In the second plating step, plating other than chrome plating is not preferable. This is because, in the plating other than chrome plating, the durability of the mold is lowered due to low hardness or wear resistance, and the unevenness may be worn or damaged during use. In the antiglare film produced by such a mold, it is likely that it is difficult to obtain a sufficient antiglare function, and in addition, the possibility of occurrence of defects on the antiglare film is also high.

In addition, the surface grinding after plating is also poor. In other words, it is preferable that the step of polishing the surface is not performed after the second plating step, and the uneven surface after the chrome plating is directly used as the unevenness of the mold transferred to the surface of the resin layer on the base film. surface. This causes a flat portion to be formed on the outermost surface due to the polishing, and there is a possibility that the optical characteristics are deteriorated, and the control factor of the shape is increased, and the shape control such as reproducibility is difficult to be performed.

Thus, by applying chrome plating to the surface on which the fine surface unevenness is formed, the uneven shape can be passivated, and a mold whose surface hardness is improved can be obtained. The degree of passivation of the concavities and convexities at this time differs depending on the type of the underlying metal, the size and depth of the concavities and convexities obtained by the first etching step, and the type and thickness of the plating, and cannot be generalized, but the maximum factor for controlling the degree of passivation is still It is the plating thickness. When the thickness of the chrome plating is thin, the effect of passivating the surface shape of the unevenness obtained before the chrome plating is insufficient, and the optical characteristics of the anti-glare film obtained by transferring the uneven shape are not good. On the other hand, when the chrome plating thickness is too thick, in addition to the deterioration in productivity, a plating defect called a protrusion of a bulge is generated, which is not preferable. Therefore, the chrome plating thickness is preferably in the range of 1 to 10 μm, particularly preferably in the range of 3 to 6 μm.

The chrome plating layer formed in the second plating step is preferably formed to have a Vickers hardness of 800 or more, and more preferably 1,000 or more. This is because when the Vickers hardness of the chrome plating layer is less than 800, the hardness of the chrome plating layer is lowered due to the decrease in durability when the mold is used, and the possibility of abnormality in the plating bath composition and the electrolysis condition during the plating treatment. High, the possibility of a less favorable impact on the occurrence of defects is increased.

Moreover, in the manufacturing method of the mold for producing the anti-glare film of the present invention, it is preferable that the etching process is performed between the above-mentioned [7] photosensitive resin film peeling step and [8] second plating step. The second etching step of passivating the uneven surface formed in the first etching step. In the second etching step, the first surface uneven shape 15 formed by the first etching step using the photosensitive resin film as a mask is passivated by an etching treatment. By the second etching treatment, the portion of the first surface uneven shape 15 formed by the first etching step can be eliminated, and the optical characteristics of the antiglare film produced by using the obtained mold can be improved. The direction changes. In Fig. 14, it is schematically shown that the first surface uneven shape 15 of the mold base material 7 is passivated by the second etching treatment, and a portion having a steep surface inclination is passivated, and a gentle surface inclination is formed. The state of the second surface uneven shape 18.

The etching treatment in the second etching step is generally the same as in the first etching step, and generally, a ferric chloride (FeCl ₃ ) solution, a copper chloride (CuCl ₂ ) solution, an alkali etching solution (Cu(NH ₃ ) ₄ Cl ₂ ), or the like is used. This is carried out by etching the metal surface, but it is also possible to use a strong acid such as hydrochloric acid or sulfuric acid or a reverse electrolytic etching by applying a potential opposite to that at the time of electrolytic plating. The degree of passivation of the unevenness after the etching treatment differs depending on the type of the underlying metal, the etching method, and the size and depth of the unevenness obtained by the first etching step, and cannot be generalized, but the maximum factor for controlling the degree of passivation is etching. the amount. The amount of etching referred to herein is the same as the first etching step, and refers to the thickness of the substrate removed by etching. When the etching amount is small, the effect of passivating the surface shape of the unevenness obtained by the first etching step is insufficient, and the optical characteristics of the anti-glare film obtained by transferring the uneven shape are not good. On the other hand, when the etching amount is too large, the uneven shape almost disappears and becomes a nearly flat mold, so that the anti-glare property cannot be exhibited. Therefore, the etching amount is preferably in the range of 1 to 50 μm, and in addition, in order to obtain an anti-glare film having a fine uneven surface containing 95% or more of the surface having an inclination angle of 5 or less, it is preferably in the range of 4 to 20 μm. Inside. The etching treatment in the second etching step can be performed by one etching process or by dividing the etching process into two or more steps, similarly to the first etching step. Here, when the etching treatment is carried out in two or more steps, the total etching amount of the etching treatment of two or more times is preferably within the above range.

<Anti-glare polarizing plate>

The anti-glare film of the present invention is capable of exhibiting better anti-glare properties and exhibiting good contrast, and effectively prevents the deterioration of visibility due to the occurrence of "whitening" and "flash spots". When viewing an image display device, the viewing performance is good. When the image display device is a liquid crystal display, the anti-glare film can be applied to the polarizing plate. In other words, the polarizing plate is generally in the form of a protective film bonded to at least one surface of a polarizing film composed of a polyvinyl alcohol-based resin having an iodine or a dichroic dye adsorbed, but it can be prevented by the present invention. The glare film constitutes one of the protective films. The anti-glare polarizing plate can be formed by bonding a polarizing film to the base film side of the anti-glare film and the anti-glare film of the present invention. At this time, the other surface of the polarizing film may be in an unlaminated state, or in a state in which a protective film or another optical film is laminated, or an adhesive layer which is laminated to be bonded to the liquid crystal cell. Further, on the protective film in which a polarizing plate of a protective film is bonded to at least one surface of the polarizing film, the antiglare film of the present invention can be bonded to the base film side to form an antiglare polarizing plate. Further, in the polarizing plate in which the protective film is bonded to at least one surface of the polarizing film, the base film may be bonded to the polarizing film as the protective film, and the antiglare layer may be formed on the base film. Thereby, an anti-glare polarizing plate is formed.

example

The invention is described in more detail in the following examples, but the invention is not limited thereto. The evaluation methods of the anti-glare film and the anti-glare film production pattern of the following examples are as follows.

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

The surface shape of the anti-glare film was measured using a three-dimensional microscope PLμ 2300 (manufactured by Sensofar Co., Ltd.). In order to prevent the warpage of the sample, an optically transparent adhesive is applied to the glass substrate so that the uneven surface is a surface, and then used for measurement. At the time of measurement, the measurement was performed by setting the magnification of the objective lens to 10 times. The horizontal decomposition energy Δx and Δy were both 1.66 μm, and the measurement area was 850 μm × 850 μm.

(The ratio of the energy spectrum of the elevation H ₁ ² /H ₂ ² and H ₃ ² /H ₂ ² )

From the above measured data, the elevation of the fine concave and convex surface of the anti-glare film is obtained as a two-dimensional function h(x, y), and the obtained two-dimensional function h(x, y) is subjected to discrete Fourier transform to obtain Two-dimensional function H(f _x , f _y ). The two-dimensional function H(f _x , f _y ) is squared to calculate the two-dimensional function H ² (f _x , f _y ) of the energy spectrum, and H ² (0, f from the profile curve of f _x =0 _y) in the spatial frequency spectrum is obtained in 0.01μm ^-1 H 0.04μm ^-1 in the spatial frequency spectrum ^₁₂ H _{² 2,} and calculates a ratio spectrum H _{1 ²} / H ^{2 2.} Further, the energy spectrum H ₃ ² in the spatial frequency of 0.1 μm ^-1 was obtained, and the energy spectrum ratio H ₃ ² /H ₂ ² was calculated.

(the angle of inclination of the fine concave surface)

Based on the above measured data and calculated according to the above algorithm, a histogram of the inclination angle of the concave-convex surface is prepared, and the distribution of each inclination angle is obtained from the figure, and the inclination angle is calculated to be 5 or less. The proportion of the face.

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

(haze)

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 Co., Ltd.) according to this specification. In order to prevent the warpage of the anti-glare film, an optically transparent adhesive is used, and the surface of the uneven surface is bonded to the glass substrate, and then applied to the measurement. In general, when the haze is increased, the image applied to the image display device is darkened, and as a result, the front contrast is easily lowered. Therefore, the lower haze is better.

[3] Determination of mechanical strength (pencil hardness) and moisture permeability of anti-glare film

(pencil hardness)

The pencil hardness of the antiglare film was measured by the method specified in JIS K 5600-5-4. Specifically, it was measured using a power pencil scraping hardness tester (manufactured by Yasuda Seiki Co., Ltd.) in accordance with this specification and carrying a load of 500 g.

(moisture permeability)

The moisture permeability of the anti-glare film was measured under the conditions of a temperature of 40 ° C and a relative humidity of 90% by a method defined in JIS Z0208.

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

(mapping, visual assessment of whitening)

In order to prevent the reflection from the inner surface of the anti-glare film, the anti-glare film is bonded to the black acrylic resin plate so that the uneven surface is a surface, and is visually observed from the uneven surface side in the bright room where the fluorescent lamp is turned on. The degree of whitening of the mapping of the fluorescent lamps is evaluated visually. Mapping, whitening, and texture were evaluated in the following three stages with a period of 1 to 3, respectively.

Mapping 1: No mappings were observed.

2: A few mappings were observed.

3: The mapping is clearly observed.

Whitening 1: No whitening was observed.

2: A little whitewash was observed.

3: Whitening was clearly observed.

(evaluation of flash spots)

The freckle was evaluated in the following manner. In other words, the polarizing plate on both sides of the front and back sides was peeled off from a commercially available liquid crystal television (LC-32GH3 (manufactured by Sharp Corporation)). Then, the polarizing plate "Sumikalan SRDB31E" (manufactured by Sumitomo Chemical Co., Ltd.) was bonded to the back side and the display side to replace the original polarizing plate so that the respective absorption axes coincided with the absorption axis of the original polarizing plate. Then, the antiglare film shown in each of the following examples was applied so that the uneven surface became a surface, and the intermediate adhesive was further bonded to the display surface side polarizing plate. In this state, observation was visually observed from a position of about 30 cm from the sample, whereby the speckle was subjected to functional evaluation in 7 stages. Level 1 is the state in which no flash spots are observed at all, level 7 is equivalent to the state in which very severe flash spots are observed, and level 3 is a state in which some flash spots are observed.

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

The tone of the created pattern data is represented by a two-dimensional discrete function g(x, y). The horizontal decomposition energies Δx and Δy of the discrete function g(x, y) are both 2 μm. 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 ). The two-dimensional function G(f _x , f _y ) is squared to calculate the two-dimensional function G ² (f _x , f _y ) of the energy spectrum, and the G ² (0, f) of the profile curve from f _x =0 _{In y} ), it is evaluated whether or not there is a maximum value in a spatial frequency range of more than 0 μm ^-1 and 0.04 μm ^-1 or less.

<Example 1>

(Production of mold for manufacturing anti-glare film)

First, a copper ballard plating was applied to the surface of an aluminum roll having a diameter of 200 mm (according to JIS A5056). The copper ballard plating is formed by a copper plating layer/thin silver plating layer/surface copper plating layer, and the thickness of the entire plating layer is set to be about 200 μm. The copper plating surface is mirror-polished, and a photosensitive resin is applied onto the polished copper plating surface, and dried to form a photosensitive resin film. Next, a pattern in which a plurality of patterns composed of the image data shown in Fig. 15 are repeatedly arranged is repeatedly repeated, and exposure and development are performed by laser light on the photosensitive resin film. Exposure and development by laser light were carried out using Laser Stream FX (manufactured by Think Laboratory). A positive photosensitive resin is used for the photosensitive resin film. The pattern shown in Fig. 15 is a low spatial frequency component for removing a spatial frequency of 0.04 μm ^-1 or less and a high spatial frequency component of 0.1 μm ^-1 or more for a pattern in which a plurality of dots having a spot diameter of 12 μm are randomly arranged. It is made by a bandpass filter.

Then, the first etching treatment (etching amount: 3 μm) was performed with a copper chloride solution. After the first etching treatment, the photosensitive resin film was removed from the roll, and the second etching treatment was performed again with a copper chloride solution (etching amount: 10 μm). Then, the mold A was produced by performing chrome plating so that the chrome plating thickness was 4 μm.

(Production of substrate film)

The acrylic resin composition containing 30 parts by weight of the acrylic rubber particles in a copolymer of methyl methacrylate/methyl acrylate = 96/4 (weight ratio) (refractive index 1.49) and 70 parts by weight of the acrylic resin composition, in the first extrusion The press (a screw diameter of 65 mm, a single shaft, and a vent hole (manufactured by Toshiba Machine Co., Ltd.)) was melt-blended and supplied to a feed block. Further, 30 parts by weight of the acrylic rubber particles are contained in a copolymer of methyl methacrylate/methyl acrylate = 96/4 (weight ratio) (refractive index 1.49), 70 parts by weight of an acrylic resin composition, 2 An extruder (a screw diameter of 45 mm, a single shaft, and a vent hole (manufactured by Hitachi Shipbuilding Co., Ltd.)) was melt-blended and supplied to a flow divider. The resin supplied from the first extruder to the flow divider is an intermediate layer, and the resin supplied from the second extruder to the flow divider is formed into a surface layer (double-sided), and co-extrusion is performed at 265 ° C. A base film A having a three-layer structure having a thickness of 80 μm (intermediate layer 50 μm, surface layer 15 μm × 2) was produced through a roll unit set at 85 °C.

(formation of anti-glare layer)

The photocurable resin composition "GRANDIC 806T" (manufactured by Dainippon Ink and Chemicals Co., Ltd.) was dissolved in ethyl acetate to form a 50% by weight solution, and then Lucirin TPO (manufactured by BASF Corporation), which is a photopolymerization initiator, was used. Chemical name: 2,4,6-trimethylbenzimidium diphenylphosphine oxide), and a coating liquid was prepared so that the curable resin component was added in an amount of 5 parts by weight per 100 parts by weight. The coating liquid was applied to the base film A so that the coating thickness after drying was 6 μm, and dried in a dryer set at 60 ° C for 3 minutes. The base film A after drying is pressed against the uneven surface of the previously obtained mold A by a rubber roller so that the photocurable resin composition layer becomes the mold side, and is adhered. In this state, light from a high-pressure mercury lamp having a strength of 20 mW/cm ² was irradiated from the side of the base film A so that the amount of light converted into h-rays was 200 mJ/cm ² to form a photocurable resin composition layer. hardening. Then, the base film A is peeled off from the mold by each of the hardening resins, and a transparent anti-glare film A composed of a laminate of a cured resin (anti-glare layer) having irregularities on the surface and the base film A is produced.

<Example 2>

In the exposure process of the mold making process, a pattern in which a plurality of patterns composed of the image data shown in FIG. 16 are continuously arranged is repeatedly repeated, and exposure is performed on the photosensitive resin film by laser light to make the first The mold B was produced in the same manner as in the first embodiment except that the etching amount of the etching treatment was set to 5 μm and the etching amount of the second etching treatment was set to 12 μm. An anti-glare film B was produced in the same manner as in Example 1 except that the obtained mold B was used. The pattern shown in Fig. 16 is a low spatial frequency component for removing a spatial frequency of 0.035 μm ^-1 or less and a high spatial frequency component of 0.135 μm ^-1 or more for a pattern in which a plurality of dots having a spot diameter of 12 μm are randomly arranged. It is made by a bandpass filter.

<Comparative Example 1>

An anti-glare film C was produced in the same manner as in Example 1 except that a cellulose acetate triacetate (TAC) film having a thickness of 80 μm was used instead of the base film A.

<Comparative Example 2>

First, the surface of an aluminum roll having a diameter of 300 mm (according to AIS56 of JIS) was mirror-polished, and a sand blasting apparatus (manufactured by Fujifilm Co., Ltd.) was used, and a blasting pressure of 0.1 MPa (measured pressure) and a bead amount of 8 g/cm ² ( The amount of the surface area of the roll was 1 cm ² , and zirconia beads TZ-SX-17 (manufactured by Tosoh Co., Ltd., average particle diameter: 20 μm) was sandblasted to the ground aluminum surface to form irregularities on the surface. The obtained aluminum roll with irregularities was subjected to electroless nickel plating to prepare a mold C. At this time, the thickness of the electroless nickel plating was set to 15 μm. An anti-glare film D was produced in the same manner as in Example 1 except that the obtained mold C was used.

The measurement and evaluation results of the above [1] to [4] of the obtained antiglare films A to D are summarized in Table 1. Further, Fig. 17 shows the f _x =0 in the energy spectrum G ² (f _x , f _y ) obtained from the pattern used in the production of the mold A of the first embodiment and the mold B of the second embodiment. section. From Fig. 17, it can be seen that the energy spectrum of the pattern used in the production of the mold A of the first embodiment and the mold B of the second embodiment is in a spatial frequency range of more than 0 μm ^-1 and 0.04 μm ^-1 or less. Does not have a maximum value.

From the results shown in the first table, it was found that the anti-glare film A and the anti-glare film B satisfying all the requirements of the present invention did not generate speckle at all, showed sufficient anti-glare property, and did not produce whitening. . Further, since the haze is also low, even when it is disposed in the image display device, the contrast is not lowered. Further, the pencil has high hardness and strong mechanical strength, and has low moisture permeability and high moisture resistance.

On the other hand, the anti-glare film C which does not use the base film which consists of an acrylic resin shows the anti-glare performance, but pencil hardness and moisture resistance are more than anti-glare film A and anti-glare film B. low. Further, the anti-glare film D which is not produced according to the predetermined pattern generates a flare because the energy spectrum ratio H ₁ ² /H ₂ ^{2 does} not satisfy the requirements of the present invention.

1. . . Anti-glare film

2. . . Fine bump

3. . . Anti-glare film projection surface

6a, 6b, 6c, 6d. . . Normal vector

7. . . Mold base

8. . . Grinded surface

9. . . Photosensitive resin film

10. . . Exposure area

11. . . Unexposed area

12. . . Mask

13. . . No mask

15. . . First surface relief shape

16. . . Chrome plating

17. . . Chromed surface

18. . . Second surface relief shape

101. . . Substrate film

102. . . Anti-glare layer

103. . . Fine uneven surface

Fig. 1 is a cross-sectional view schematically showing an example of an anti-glare film of the present invention.

Fig. 2 is a perspective view schematically showing the surface of the anti-glare film of the present invention.

Fig. 3 is a schematic diagram showing a state in which the function h(x, y) indicating the elevation is discretely obtained.

Fig. 4 is a view showing an example of the elevation of the fine uneven surface of the antiglare layer of the antiglare film of the present invention by a two-dimensional discrete function h(x, y).

Figure 5 is a diagram showing the energy spectrum H ² (f _x , f _y ) of the elevation obtained by discrete Fourier transform of the two-dimensional function h(x, y) shown in Fig. 4 in white and black gradations. .

Fig. 6 is a view showing a cross section of f _x =0 in the energy spectrum H ² (f _x , f _y ) shown in Fig. 5.

Fig. 7 is a schematic view for explaining a method of measuring the inclination angle of the fine uneven surface.

Fig. 8 is a graph showing an example of a histogram of the oblique angle distribution of the fine uneven surface of the antiglare layer provided in the antiglare film.

Figure 9 is a diagram showing a portion of image data that can be used to make the pattern used in the anti-glare film of the present invention.

Figure 10 shows the energy spectrum G ² (f _x , f _y ) obtained by discrete Fourier transform of the two-dimensional function g(x, y) of the tone shown in Fig. 9 in white and black gradation. Figure.

Fig. 11 is a view showing a cross section of f _x =0 in the energy spectrum G ² (f _x , f _y ) shown in Fig. 10.

Fig. 12 (a) to (e) are diagrams schematically showing a preferred example of the first half of the method for manufacturing a mold.

Fig. 13 (a) to (c) are diagrams schematically showing a preferred example of the latter half of the method for manufacturing a mold.

Fig. 14 (a) to (b) are diagrams schematically showing a state in which the uneven surface formed in the first etching step is passivated by the second etching step.

Fig. 15 is a view showing a pattern used in the production of the mold of Example 1.

Fig. 16 is a view showing a pattern used in the production of the mold of Example 2.

Fig. 17 is a view showing a cross section of f _x =0 in the energy spectrum G ² (f _x , f _y ) of the pattern shown in Figs. 15 and 16.

101. . . Substrate film

102. . . Anti-glare layer

103. . . Fine uneven surface

Claims (4)

An anti-glare film comprising: a base film; and an anti-glare layer laminated on the base film and having an uneven surface, wherein the anti-glare film is characterized in that the base film contains an acrylic resin; and the spatial frequency is 0.01 μm. the elevation of the surface irregularities of the spectrum ^-1 H ₁ ² with the spatial frequency of surface irregularities of 0.04μm elevation ^-1 H ratio of the spectrum of H _{² 2 1 ²} / H ^{2 2,} based located 3-20 The ratio of the energy spectrum H ₃ ² of the elevation of the aforementioned concave-convex surface in the spatial frequency of 0.1 μm ^-1 to the energy spectrum H ₂ ² of the elevation of the aforementioned concave-convex surface in the spatial frequency of 0.04 μm ^-1 H ₃ ² /H ₂ ² is 0.1 or less; and the uneven surface contains 95% or more of a surface having an inclination angle of 5 or less. The anti-glare film according to claim 1, wherein the base film has a thickness of 20 μm or more and 100 μm or less. The anti-glare film according to claim 1, wherein the substrate film contains acrylic rubber particles. An anti-glare polarizing plate comprising: an anti-glare film according to claim 1; and a polarizing film laminated on a surface of the base film opposite to the anti-glare layer.