JP2011118327A - Anti-dazzle processing method, and methods of manufacturing anti-dazzle film and die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-dazzle processing method for a transparent substrate which prevents the deterioration of visibility caused by whitening while showing excellent anti-dazzle performance, and provides high contrast without causing dazzling even if it is applied to a high-definition image display device, a method of manufacturing an anti-dazzle film, and a method of manufacturing a metallic die suitably used in the method. <P>SOLUTION: The anti-dazzle processing method for the transparent substrate, the method of manufacturing the anti-dazzle film, and the method of manufacturing the metallic die suitably used in the method are provided. The methods include: a step of applying a filter at least eliminating or decreasing low spatial frequency components from spatial frequency components included in a first pattern to form a second pattern; and a step of processing concave and convex shapes on the transparent substrate using the pattern. The methods may include: a step of manufacturing a third pattern which is converted to discrete information by means of a dithering method; and a step of manufacturing a fourth pattern by the movement of an isolated pixel by means of a Monte-Carlo method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an antiglare treatment method and a method for producing an antiglare film, and a method for producing a metal mold used in such an antiglare treatment method and a method for producing an antiglare film.

  In an image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT) display, an organic electroluminescence (EL) display, and the like, when external light is reflected on the display surface, the visibility is significantly impaired. Conventionally, in order to prevent such reflection of external light, display is performed using a television or personal computer that emphasizes image quality, a video camera or digital camera that is used outdoors with strong external light, and reflected light. In a mobile phone or the like, a process for preventing external light from being reflected on the surface of the image display device is performed. The processing performed on the surface of such an image display device includes antireflection processing using interference by the optical multilayer film and prevention of blurring the reflected image by scattering incident light by forming fine irregularities on the surface. It is roughly divided into dazzling treatment. The former non-reflective treatment increases the cost because it is necessary to form a multilayer film having a uniform optical film thickness. On the other hand, since the latter anti-glare treatment can be performed relatively inexpensively, it is widely used for applications such as large personal computers and monitors.

  The antiglare treatment of the image display device is typically performed by bonding an antiglare film with antiglare properties to the surface of the image display device. Conventionally, an anti-glare film, for example, a resin solution in which fine particles are dispersed is applied on a base sheet by adjusting the film thickness, and the fine particles are exposed on the surface of the coating film so that random surface irregularities are formed on the base sheet. It is manufactured by the method of forming on top. However, the antiglare film manufactured using a resin solution in which such fine particles are dispersed has an influence on the arrangement and shape of surface irregularities depending on the dispersion state and application state of the fine particles in the resin solution. It is difficult to obtain surface irregularities as described above, and when the haze of the antiglare film is set low, there is a problem that a sufficient antiglare effect cannot be obtained. Furthermore, when such a conventional anti-glare film is disposed on the surface of the image display device, the entire display surface becomes whitish due to scattered light, and the display becomes cloudy, so-called “whiteness” is likely to occur. There was a problem. Also, with the recent high definition of image display devices, the pixels of the image display device and the surface uneven shape of the antiglare film interfere with each other, and as a result, a luminance distribution occurs and the display surface becomes difficult to see. There was also a problem that the “glare” phenomenon was likely to occur. In order to eliminate glare, there is an attempt to scatter light by providing a refractive index difference between the binder resin and the fine particles dispersed therein, but such an antiglare film is disposed on the surface of the image display device. In some cases, there is a problem that the contrast tends to be lowered due to light scattering at the interface between the fine particles and the binder resin.

  On the other hand, there is also an attempt to develop anti-glare properties only by fine irregularities formed on the surface of the transparent resin layer without containing fine particles. For example, in Japanese Patent Laid-Open No. 2002-189106 (Patent Document 1), a three-dimensional 10-point average roughness on a transparent resin film and an average distance between adjacent convex portions on a three-dimensional roughness reference surface are described. Further, an antiglare film is disclosed in which a cured product layer of an ionizing radiation curable resin layer having fine surface irregularities each satisfying a predetermined value is laminated. This antiglare film is manufactured by curing the ionizing radiation curable resin in a state where the ionizing radiation curable resin is sandwiched between the embossing mold and the transparent resin film. However, even with the antiglare film disclosed in Patent Document 1, it has been difficult to achieve a sufficient antiglare effect, suppression of whitening, high contrast, and suppression of glare.

  It is also possible to use a film having fine irregularities on the surface as a light diffusion layer disposed on the back side of the liquid crystal display device, instead of an antiglare film disposed on the display surface of the display device. No. 6-34961 (Patent Document 2), Japanese Unexamined Patent Application Publication No. 2004-45471 (Patent Document 3), Japanese Unexamined Patent Application Publication No. 2004-45472 (Patent Document 4), and the like. Among these, in Patent Documents 3 and 4, as a method for forming irregularities on the surface of the film, an embossing roll having a shape with inverted irregularities is filled with an ionizing radiation curable resin liquid, and the filled resin is made of a roll intaglio. A transparent base material running in synchronization with the rotation direction is brought into contact, and when the transparent base material is in contact with the roll intaglio, the resin between the roll intaglio and the transparent base is cured, and at the same time as cured, a cured resin is cured. A method is disclosed in which a laminate of a cured resin and a transparent substrate is peeled off from a roll intaglio after the substrate and the transparent substrate are brought into close contact with each other.

  However, in the methods disclosed in Patent Documents 3 and 4, the composition of the ionizing radiation curable resin liquid that can be used is limited, and leveling as when applied by diluting with a solvent cannot be expected. It is expected that there is a problem in the uniformity of the film thickness. Furthermore, in the methods disclosed in Patent Documents 3 and 4, since it is necessary to directly fill the embossing roll intaglio with the resin liquid, in order to ensure the uniformity of the uneven surface, the embossing roll intaglio has high mechanical accuracy. There was a problem that it was required and it was difficult to produce an embossing roll.

  Next, as a method for producing a roll used for producing a film having irregularities on the surface, for example, in Patent Document 2 described above, a cylindrical body is made using metal or the like, and electronic engraving, etching, sandblasting is performed on the surface. A method of forming irregularities by such a method is disclosed. Japanese Unexamined Patent Application Publication No. 2004-29240 (Patent Document 5) discloses a method for producing an embossing roll by a bead shot method, and Japanese Unexamined Patent Application Publication No. 2004-90187 (Patent Document 6). A method of producing an embossing roll is disclosed through a step of forming a metal plating layer on the surface, a step of mirror polishing the surface of the metal plating layer, and a step of peening treatment as necessary.

  However, in such a state that the surface of the embossing roll is subjected to blasting treatment, the uneven diameter distribution caused by the particle size distribution of the blast particles is generated, and the depth of the dent obtained by blasting can be controlled. It was difficult to obtain an uneven shape excellent in antiglare function with good reproducibility.

  Further, Patent Document 1 described above describes that a concavo-convex surface is formed by a sandblasting method or a bead shot method, preferably using a roller having a chromium plating on the surface of iron. Furthermore, it is preferable to use the mold surface with such irregularities after applying chrome plating for the purpose of improving durability during use, thereby making it harder and preventing corrosion. There is also a statement that it is possible. On the other hand, in each of the examples of Patent Documents 3 and 4 described above, the surface of the iron core is chrome-plated and subjected to # 250 liquid sand blasting, and then chrome-plating again to form a fine uneven shape on the surface. It is described to do.

  However, in such an embossing roll manufacturing method, since blasting and shots are performed on chromium plating with high hardness, it is difficult to form unevenness, and it is difficult to precisely control the shape of the formed unevenness. It was. Further, as described in Japanese Patent Application Laid-Open No. 2004-29672 (Patent Document 7), the surface of the chrome plating is often rough depending on the material and the shape of the base, and the surface of the concavo-convex formed by blasting. Since fine cracks generated by chrome plating are formed on the surface, there is a problem that it is difficult to design what kind of irregularities can be formed. Furthermore, since there are fine cracks generated by chrome plating, there is also a problem that the scattering characteristics of the finally obtained antiglare film change in an unfavorable direction. Furthermore, since the finished roll surface varies in various ways depending on the combination of the embossing roll base material surface and plating type, in order to obtain the required surface irregularities accurately, the appropriate roll surface material and There was also a problem that an appropriate plating type had to be selected. Furthermore, even if the desired surface irregularity shape is obtained, the durability during use may be insufficient depending on the type of plating.

  Japanese Patent Laid-Open No. 2000-284106 (Patent Document 8) describes performing a sandblasting process on a base material and then performing an etching process and / or a thin film laminating process. However, metal plating is performed before the sandblasting process. There is no description or suggestion of providing a layer. Japanese Patent Laid-Open No. 2006-53371 (Patent Document 9) describes that an electroless nickel plating is performed after a substrate is polished and sandblasted. Japanese Patent Application Laid-Open No. 2007-187852 (Patent Document 10) discloses that an embossed plate is produced by performing copper plating or nickel plating on a base material, polishing, sandblasting, and then chromium plating. It is described. Further, Japanese Patent Application Laid-Open No. 2007-237541 (Patent Document 11) discloses that after copper plating or nickel plating, polishing, sandblasting, etching, or copper plating, and then chromium plating. To produce an embossed plate. In these production methods using sandblasting, it is difficult to form the surface uneven shape in a precisely controlled state, so that a relatively large uneven shape having a period of 50 μm or more is also produced in the surface uneven shape. As a result, there is a problem that the so-called glare that the large uneven shape and the pixels of the image display device interfere with each other and a luminance distribution is generated and the display surface is difficult to see is likely to occur.

JP 2002-189106 A JP-A-6-34961 JP 2004-45471 A JP 2004-45472 A JP 2004-29240 A JP 2004-90187 A JP 2004-29672 A JP 2000-284106 A JP 2006-53371 A JP 2007-188792 A JP 2007-237541 A

  When the object of the present invention is applied to an image display device, it can prevent deterioration in visibility due to whitish while exhibiting excellent anti-glare performance, and is applied to a high-definition image display device Is providing an anti-glare treatment method for a transparent substrate that can exhibit high contrast without causing glare.

  Another object of the present invention is to provide a high-definition image display device that can prevent deterioration in visibility due to whitish while exhibiting excellent anti-glare performance when placed on the surface of the image display device. The present invention also provides a method for producing an antiglare film that can exhibit high contrast without causing glare even when it is disposed on the surface.

  Still another object of the present invention is to provide an image display device having antiglare properties having the above display characteristics. Still another object of the present invention is to provide a method for producing a metal mold which is suitably used in the above-described antiglare treatment method and antiglare film production method.

  As a result of intensive studies to achieve the above object, the present inventors have created a first pattern composed of images, image data, etc., and then the spatial frequency is less than a specific value with respect to the first pattern. According to the method of creating the second pattern by applying a filter that at least removes or reduces a certain low spatial frequency component, and processing the concavo-convex shape on the transparent substrate based on the second pattern, processing reproduction The present inventors have found that a concavo-convex shape can be imparted on a transparent substrate with good performance, a sufficient antiglare effect is exhibited, and the occurrence of whitening and glare and the reduction in contrast are sufficiently suppressed. Further, as the filter, a low spatial frequency component having a spatial frequency lower than a specific lower limit value B ′ is removed or reduced from among the spatial frequency components included in the first pattern, and a spatial frequency equal to or higher than the lower limit value B ′ is obtained. A high-pass filter that extracts a spatial frequency component (hereinafter, the lower limit value B ′ is also referred to as a spatial frequency range lower limit value B ′) or a specific lower limit value among the spatial frequency components included in the first pattern A low spatial frequency component having a spatial frequency lower than B and a high spatial frequency component having a spatial frequency exceeding a specific upper limit T are removed or reduced, and a spatial frequency in a specific range from the lower limit B to the upper limit T (Hereinafter, the lower limit value B and the upper limit value T of the specific range are also referred to as the spatial frequency range lower limit value B and the spatial frequency range upper limit value T, respectively). .) Found that it is possible to suitably use a band-pass filter for extracting. The present invention has been completed based on such findings and further various studies.

  The present invention provides a low space in which a spatial frequency is less than a specific value from a spatial frequency component included in the first pattern with respect to the first pattern in which a plurality of dots are randomly arranged or the brightness distribution is arranged. Applying a filter that at least removes or reduces a frequency component to create a second pattern, and using the second pattern to process a concavo-convex shape on the transparent substrate A dazzling treatment method is provided.

As the filter, a high-pass filter that removes or reduces only a low spatial frequency component having a spatial frequency less than a specific value from the spatial frequency component included in the first pattern can be preferably used. This high-pass filter preferably removes or reduces only the low spatial frequency component having a spatial frequency of less than 0.01 μm ⁻¹ from the spatial frequency component included in the first pattern.

  In addition, as the filter, a low spatial frequency component whose spatial frequency is less than a specific value is removed or reduced from a spatial frequency component included in the first pattern, and a high spatial frequency component whose spatial frequency exceeds a specific value is removed. Alternatively, it is also preferable to use a band pass filter that extracts a spatial frequency component in a specific range by reducing the frequency band.

In the anti-glare treatment method of the present invention, the lower limit B of the spatial frequency in the spatial frequency component in the specific range extracted by application of the bandpass filter is preferably 0.01 μm ⁻¹ or more, and the upper limit T is 1 / (D × 2) μm ⁻¹ or less. Here, D (μm) is the resolution of the processing apparatus used when processing the concavo-convex shape on the transparent substrate. The upper limit value T and the lower limit value B of the spatial frequency are expressed by the following formula (1):
0.20 <2 × (T−B) / (T + B) <0.80 (1)
It is preferable to satisfy.

  As the first pattern, for example, a pattern formed by randomly arranging a plurality of dots can be preferably used.

  The anti-glare treatment method of the present invention preferably further includes a step of creating a third pattern converted into discretized information by applying a dithering method to the second pattern. In this case, the step of processing the concavo-convex shape on the transparent substrate is performed using the third pattern. As the dithering method, an error diffusion method can be preferably used. The third pattern is preferably a pattern converted into information discretized in two stages. In one preferred embodiment of the anti-glare processing method of the present invention, the third pattern is created by applying an error diffusion method for diffusing a conversion error in a range of 3 pixels to 6 pixels.

  The anti-glare processing method of the present invention is a process of creating a fourth pattern by moving isolated black or white pixels by the Monte Carlo method with respect to the third pattern converted into information discretized in two stages. It is preferable to further comprise. In this case, the step of processing the concavo-convex shape on the transparent substrate is performed using the fourth pattern.

  The step of processing the concavo-convex shape on the transparent substrate is to produce a mold having a concavo-convex surface using the second pattern, the third pattern, or the fourth pattern, and the concavo-convex surface of the mold is transparent. It is preferable to include the process of transferring on a base material.

  The step of processing the concavo-convex shape on the transparent substrate is preferably performed using a processing apparatus that performs processing based on the discretized information of the third pattern or the fourth pattern.

  Further, according to the present invention, the spatial frequency is less than a specific value from the spatial frequency component included in the first pattern with respect to the first pattern in which a plurality of dots are randomly arranged or the brightness distribution is arranged. An anti-glare film comprising a step of creating a second pattern by applying a filter that at least removes or reduces a spatial frequency component, and a step of processing a concavo-convex shape on a transparent substrate using the second pattern A manufacturing method is provided.

As the filter, a high-pass filter that removes or reduces only a low spatial frequency component having a spatial frequency less than a specific value from the spatial frequency component included in the first pattern can be preferably used. This high-pass filter preferably removes or reduces only the low spatial frequency component having a spatial frequency of less than 0.01 μm ⁻¹ from the spatial frequency component included in the first pattern.

  In addition, as the filter, a low spatial frequency component whose spatial frequency is less than a specific value is removed or reduced from a spatial frequency component included in the first pattern, and a high spatial frequency component whose spatial frequency exceeds a specific value is removed. Alternatively, it is also preferable to use a band pass filter that extracts a spatial frequency component in a specific range by reducing the frequency band.

In the method for producing an antiglare film of the present invention, the lower limit B of the spatial frequency in the spatial frequency component of the specific range extracted by application of the bandpass filter is preferably 0.01 μm ⁻¹ or more, and the upper limit. T is preferably 1 / (D × 2) μm ⁻¹ or less. D has the same meaning as above. The upper limit value T and the lower limit value B of the spatial frequency are expressed by the following formula (1):
0.20 <2 × (T−B) / (T + B) <0.80 (1)
It is preferable to satisfy.

  As the first pattern, for example, a pattern formed by randomly arranging a plurality of dots can be preferably used.

  The method for producing an antiglare film of the present invention preferably further includes a step of creating a third pattern converted into discretized information by applying a dithering method to the second pattern. In this case, the step of processing the concavo-convex shape on the transparent substrate is performed using the third pattern. As the dithering method, an error diffusion method can be preferably used. The third pattern is preferably a pattern converted into information discretized in two stages. In one preferred embodiment of the manufacturing method of the present invention, the third pattern is created by applying an error diffusion method in which a conversion error is diffused in a range of 3 pixels or more and 6 pixels or less.

  The anti-glare film manufacturing method of the present invention creates a fourth pattern by moving isolated black or white pixels by the Monte Carlo method with respect to the third pattern converted into information discretized in two stages. It is preferable to further include the step of performing. In this case, the step of processing the concavo-convex shape on the transparent substrate is performed using the fourth pattern.

  The step of processing the concavo-convex shape on the transparent substrate is to produce a mold having a concavo-convex surface using the second pattern, the third pattern, or the fourth pattern, and the concavo-convex surface of the mold is transparent. It is preferable to include the process of transferring on a base material.

  The step of processing the concavo-convex shape on the transparent substrate is preferably performed using a processing apparatus that performs processing based on the discretized information of the third pattern or the fourth pattern.

  Furthermore, this invention provides the manufacturing method of the metal mold | die suitably used for the anti-glare processing method of the said invention, and the manufacturing method of an anti-glare film. The mold manufacturing method of the present invention includes a first plating step for performing copper plating or nickel plating on the surface of a mold base, a polishing step for polishing a surface plated by the first plating step, and polishing. A photosensitive resin film forming step for forming a photosensitive resin film on the formed surface, an exposure step for exposing the second pattern, the third pattern, or the fourth pattern on the photosensitive resin film; A development process for developing the photosensitive resin film on which the pattern, the third pattern or the fourth pattern is exposed, and an etching process using the developed photosensitive resin film as a mask, and the polished plated surface is uneven. A first etching step for forming the photosensitive resin film, a photosensitive resin film peeling step for peeling the photosensitive resin film, and a second plating step for performing chromium plating on the formed uneven surface.

  The mold manufacturing method of the present invention includes a second etching step in which the uneven shape of the uneven surface formed by the first etching step is blunted by an etching process between the photosensitive resin film peeling step and the second plating step. It is preferable to include.

  It is preferable that the concavo-convex surface formed with the chromium plating formed in the second plating step is the concavo-convex surface of the mold transferred onto the transparent substrate. That is, it is preferable to use the concavo-convex surface subjected to chrome plating as the concavo-convex surface of the mold transferred onto the transparent substrate without providing a step of polishing the surface after the second plating step.

  The chromium plating layer formed by chromium plating in the second plating step preferably has a thickness of 1 to 10 μm.

  Furthermore, according to the present invention, the antiglare treatment method for an image display device, wherein the antiglare treatment method of the present invention performs antiglare treatment on the surface of a transparent substrate provided in the image display device, and the antiglare film of the present invention. An image display apparatus provided with the anti-glare film obtained by this manufacturing method is provided.

  According to the present invention, when applied to an image display device, it is possible to prevent deterioration in visibility due to whitish while exhibiting excellent anti-glare performance, and when applied to a high-definition image display device Can provide an antiglare treatment method and an antiglare film for a transparent substrate, which can exhibit high contrast without causing glare. Further, according to the present invention, it is possible to form the concavo-convex shape that provides the excellent display characteristics on the transparent substrate with good process reproducibility. Moreover, by using the metal mold | die obtained by the method of this invention, implementation of the anti-glare processing method of this invention and manufacture of an anti-glare film can be performed with high productivity. According to the antiglare treatment method for a transparent substrate and the method for producing an antiglare film of the present invention, it is possible to provide an image display device having the above excellent display characteristics.

It is an enlarged view which shows a preferable example of the 1st pattern which can be used for the anti-glare processing method of the transparent base material of this invention, and the manufacturing method of an anti-glare film, and arrange | positioned many dots at random. It is a figure which shows a preferable example of the 1st pattern which consists of the raster image which determined the light and shade by the random number which can be used for the glare-proofing method of the transparent base material of this invention, and the manufacturing method of a glare-proof film. It is a figure which expands and shows a part of 1st pattern shown by FIG. An example of a spatial frequency distribution obtained by converting a two-dimensional array obtained from a first pattern (random dot pattern) created by randomly arranging dots into a spatial frequency domain by fast Fourier transform (FFT), and a random number It is a figure which compares with an example of the spatial frequency distribution obtained by transforming the two-dimensional arrangement | sequence obtained from the 1st pattern which consists of the raster image (random number raster image) which determined the lightness and darkness by FFT to a spatial frequency domain. It is a figure which shows the two-dimensional spatial frequency distribution obtained by converting the two-dimensional arrangement | sequence obtained from the 1st pattern shown by FIG. 1 into a spatial frequency domain by FFT. It is a figure which shows an example of the result of having performed amplitude correction | amendment with respect to the spatial frequency distribution shown with the dotted line of FIG. It is a figure which shows an example of the shape of the transmission band in the spatial frequency band (transmission band) extracted by application of a high pass filter. It is a figure which shows another example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a high pass filter. It is a figure which shows another example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a high pass filter. It is a figure which shows an example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a band pass filter. It is a figure which shows another example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a band pass filter. It is a figure which shows another example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a band pass filter. It is a figure which shows another example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a band pass filter. It is a figure which shows another example of the shape of the transmission band peak in the spatial frequency band (transmission band) extracted by application of a band pass filter. It is a figure which shows an example of the two-dimensional spatial frequency distribution after applying a band pass filter with respect to the 1st pattern which has the spatial frequency distribution shown by FIG. It is an enlarged view which shows an example of the 2nd pattern produced by applying a band pass filter to the 1st pattern shown by FIG. The figure which shows the relationship between the value of 2 * (T-B) / (T + B) and the autocorrelation coefficient maximum value obtained by binarizing the 2nd pattern obtained by application of a band pass filter by the threshold method. It is. The relationship between the value of 2 × (T−B) / (T + B) and the number of isolated small dots generated in the pattern obtained by binarizing the second pattern obtained by application of the bandpass filter by the threshold method. FIG. It is a figure which shows distribution of the accumulation rate of the gray scale index obtained by analyzing the histogram of a gray scale index about the image data shown by FIG. It is an enlarged view which shows an example of the 2nd pattern binarized by the threshold value method. FIG. 21 is a diagram showing a spatial frequency distribution obtained by converting the two-dimensional array obtained from the binarized second pattern shown in FIG. 20 into a spatial frequency domain by fast Fourier transform (FFT). It is a figure for demonstrating the weighting of the spreading | diffusion of the conversion error in the generally known error diffusion matrix. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix of Floyd & Steinberg. It is a figure which expands and shows a part of an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix of Jarvis, Judis and Nink. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to a Stucki matrix partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix of Sierra 3 Line. It is a figure which expands and partially shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix of Sierra 2 Line. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix of Sierra Filter Lite. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to a Burks matrix partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to Stevenson & Arche's matrix partially. It is a figure which expands and shows a part of 2nd pattern used for preparation of the 3rd pattern shown by FIGS. It is a figure which compares the spatial frequency distribution of the 3rd pattern binarized by the error diffusion method according to various matrices shown by FIGS. 23-30, and the spatial frequency distribution of the pattern binarized by the threshold value method. . FIG. 10 is a diagram for comparing the number of isolated dots generated when a third pattern is created by applying an error diffusion method according to a generally known error diffusion matrix as compared with a case where the number of isolated dots is created by a threshold method. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 1. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 2. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 3. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 4. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 5. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 6. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 3 + 4. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 4 + 5. It is a figure which shows an example of the error diffusion matrix whose diffusion distance is 3 + 4 + 5. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. 34 partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. 37 partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. 38 partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. 39 partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. 40 partially. It is a figure which expands and shows an example of the 3rd pattern obtained by application of the error diffusion method according to the matrix shown in FIG. 41 partially. FIG. 43 is a diagram showing a partially enlarged example of a third pattern obtained by applying the error diffusion method according to the matrix shown in FIG. 42. FIG. 43 is a diagram for comparing the number of isolated dots generated when a third pattern is generated by applying an error diffusion method according to the error diffusion matrix shown in FIGS. The spatial frequency distribution of the third pattern of FIGS. 43 to 51 binarized by the error diffusion method according to the error diffusion matrix shown in FIGS. 34 to 42 and the spatial frequency distribution of the pattern binarized by the threshold method. It is a figure to compare. It is a figure which shows the example of the processing method of the isolated dot by a Monte Carlo method. It is a figure which shows the change of the 4th pattern by the Monte Carlo method application frequency. It is a figure which shows the relationship between the number of times of applying a Monte Carlo method and the number of isolated dots generated. It is a figure which shows typically a preferable example of the first half part of the manufacturing method of the metal mold | die of this invention. It is a figure which shows typically a preferable example of the second half part of the manufacturing method of the metal mold | die of this invention. It is a figure which shows typically the state which side etching advances in a 1st etching process. It is a figure which shows typically the state where the uneven surface formed by the 1st etching process dulls by the 2nd etching process. It is a figure which expands and shows the unit pattern used in Example 1 partially. It is a figure which expands and shows the 1st pattern used for preparation of the unit pattern of Examples 1-3. It is a figure which expands and shows the unit pattern used in Example 2 partially. It is a figure which expands and shows the unit pattern used in Example 3 partially. It is a figure which expands and shows the unit pattern used in the comparative example 1 partially. It is a figure which expands and shows the unit pattern used in the comparative example 2 partially. It is a figure which expands and shows the unit pattern used in Example 4 partially. It is a figure which shows the spatial frequency distribution of the unit pattern used in Examples 1-3. It is a figure which shows the spatial frequency distribution of the unit pattern used in Comparative Examples 1-2. It is a figure which shows the spatial frequency distribution of the unit pattern used in Example 4. FIG. It is a figure which expands and shows the unit pattern used in Example 5 partially. It is a figure which shows the spatial frequency distribution of the unit pattern used in Example 5. FIG. It is a figure which shows typically the evaluation method of glare. It is a figure which expands and shows the unit pattern used in Example 6 partially. It is a figure which expands and shows the unit pattern used in Example 7 partially. 74 is a diagram comparing the spatial frequency distribution of the pattern shown in FIG. 74 with the spatial frequency distribution of the pattern shown in FIG. It is a figure which expands and shows the unit pattern used in Example 8 partially. It is a figure which expands and shows the unit pattern used in Example 9 partially. 78 is a diagram comparing the spatial frequency distribution of the pattern shown in FIG. 77 with the spatial frequency distribution of the pattern shown in FIG. 78. FIG. It is a figure which expands and shows the 1st pattern A used for preparation of the pattern 1 partially. It is a figure which expands and shows the pattern 1 partially. It is a figure which expands and shows the pattern 2 partially. It is a figure which expands and shows the pattern 3 partially. It is a figure which expands and shows the 1st pattern B used for preparation of the pattern 4 partially. It is a figure which expands and shows the pattern 4 partially. It is a figure which expands and shows the pattern 5 partially. It is a figure which expands and shows the pattern 6 partially. It is a figure which expands and shows the 1st pattern C used for preparation of the pattern 7 partially. It is a figure which expands and shows the pattern 7 partially. It is a figure which expands and shows the pattern 8 partially. It is a figure which expands and shows the pattern 9 partially. FIG. 4 is a diagram showing a partially enlarged view of a first pattern D used to create a pattern 10. It is a figure which expands and shows the pattern 10 partially. It is a figure which expands and shows the pattern 11 partially. It is a figure which expands and shows the pattern 12 partially. It is a figure which expands and shows the 1st pattern E used for preparation of the pattern 13 partially. It is a figure which expands and shows the pattern 13 partially. It is a figure which expands and shows the pattern 14 partially. It is a figure which expands and shows the pattern 15 partially. It is a figure which shows the spatial frequency distribution of 1st pattern AE. It is a figure which shows the spatial frequency distribution of the patterns 1-3. It is a figure which shows the spatial frequency distribution of the patterns 4-6. It is a figure which shows the spatial frequency distribution of the patterns 7-9. It is a figure which shows the spatial frequency distribution of the patterns 10-12. It is a figure which shows the spatial frequency distribution of the patterns 13-15. It is the figure which put together the grade of the reduction | decrease of the low spatial frequency component by the difference in the production methods of a pattern. It is a figure which shows the relationship between the production method of a pattern, and the number of isolated dots generated. It is a figure which expands and shows the 1st pattern which has arrange | positioned the brightness distribution at random. FIG. 109 is a diagram showing a partially enlarged pattern obtained by applying a high-pass filter and binarization by a threshold method with respect to the first pattern shown in FIG. 108. FIG. 109 is a diagram showing a partially enlarged pattern obtained by applying a high-pass filter and binarization by an error diffusion method to the first pattern shown in FIG. 108. FIG. 109 is a diagram showing a partially enlarged pattern obtained by applying a high-pass filter, binarization using an error diffusion method, and applying a Monte Carlo method to the first pattern shown in FIG. 108. FIG. 111 is a diagram showing the number of isolated dots generated in the patterns shown in FIGS. It is a figure which compares the spatial frequency distribution of the pattern shown by FIGS.

<Anti-glare treatment method for transparent substrate and method for producing anti-glare film>
Hereinafter, preferred embodiments of the present invention will be described in detail. In the anti-glare treatment method and the anti-glare film manufacturing method of the transparent substrate of the present invention, for example, in order to form a fine uneven shape having a specific spatial frequency distribution on the transparent substrate, a large number of dots are randomly formed. A low spatial frequency in which the spatial frequency is less than a specific value from the spatial frequency component included in the first pattern after creating the first pattern composed of the disposed pattern, the pattern in which the brightness distribution is disposed, and the like. A second pattern is created by applying a filter such as a high-pass filter or a band-pass filter that at least removes or reduces components, and the uneven shape is processed on the transparent substrate using the obtained second pattern. It is characterized by that. Further, as will be described later, an isolated dot included in a third pattern obtained by converting the obtained second pattern into information discretized by a dithering method or a binarized third pattern is converted into a Monte Carlo. It is also preferable to process the concavo-convex shape on the transparent substrate using the fourth pattern processed by the method. Thus, in this invention, a fine uneven | corrugated shape is provided on a transparent base material using a 2nd pattern, a 3rd pattern, or a 4th pattern.

  As a means for imparting antiglare properties to a transparent substrate or a means for producing an antiglare film, a method of dispersing particles in a transparent substrate is conventionally known. According to the method of the present invention using the pattern in which the low spatial frequency component is removed or reduced by applying the above, the low spatial frequency component that cannot be realized by such a conventional method is suppressed. It is possible to realize an anti-glare treatment that gives the surface shape. According to the antiglare treatment method and the antiglare film production method of the transparent substrate of the present invention, it is possible to impart an uneven shape on the transparent substrate with good process reproducibility, and a sufficient antiglare effect is expressed. In addition, it is possible to obtain an image display device in which generation of whitishness and glare and reduction in contrast are sufficiently suppressed. Moreover, when a band pass filter is applied, since the high spatial frequency component which is difficult to process unevenness is suppressed, the reproducibility of unevenness in processing of the transparent substrate surface can be further improved.

  Here, the “pattern” in the “first to fourth patterns” means a two-dimensional array of images, image data, discretized information, or an array of openings arranged on a plate.

  The image data may be raster format image data (raster image) or vector format image data (vector image). A raster image is data that represents an image as an array of colored dots (points). In the raster image, the color information of each dot is stored as a numerical value. There are various formats for storing such raster images, and a particularly common format is, for example, a bitmap. As the bitmap, a 24-bit color bitmap in which red, green, and blue intensities are each represented by an 8-bit depth, and an 8-bit grayscale bitmap in which lightness is represented by 256 stages in an 8-bit depth are particularly widely used. .

  As a format for storing a raster image, various types of data such as bitmap (Portable Network Graphics), TIFF (Tagged Image File Format), JPEG, and GIF (Graphics Interchange Format) are applied in addition to a bitmap. List formats.

  In the vector image, information such as the coordinates (position) of the starting and ending points of the line, the bending method, thickness, color, and color of the surface surrounded by the lines are stored as numerical values. A vector image includes a set of these numerical data, or a record of the radius and center coordinates of a circle, the vertex coordinates of a polygon, and the like.

  As formats for storing vector images, DXF (Drawing Interchange File) and SVG (Scalable Vector Graphics) are particularly exemplified. However, in the present invention, the vector image only needs to belong to the above definition, and is not limited to these exemplified formats. Further, the vector image is not limited to two dimensions, and may have three-dimensional information.

  Further, a vector image having a closed circle or polygonal arrangement can be easily replaced with the above-described “array of openings arranged on a plate”.

  The pattern in the present invention is not limited to an image or image data handled as described above, but may be a pattern provided as a two-dimensional array of discretized information. Various methods such as floating point (for example, 64-bit floating point) and integer (for example, signed 32-bit integer and unsigned 16-bit integer) can be used as methods for storing the discretized information.

(Creation of the first pattern)
As the first pattern, any of the patterns defined above can be used, and may be an arbitrary pattern having a change in shading or numerical values. More specifically, for example, image data in which a plurality of dots are arranged over the entire range of the image (image data in which a plurality of white dots are arranged on a black background or a plurality of black dots are arranged on a white background); A pattern having a lightness distribution, such as a pattern having a two-dimensional array of discretized information, and when applying a filter such as a high-pass filter or a band-pass filter to the first pattern ( This point will be described later), and when the Fourier transform is performed by an optical method, the plate may be provided with an aperture. Further, a photographic dry plate (dry plate) on which a pattern is formed or a transparent substrate that is partially adhered with toner can also be used as the first pattern. The arrangement of dots in the image data, the distribution of brightness and the arrangement of the openings in the plate may be regular or random (irregular). Since it is possible to obtain a concave / convex pattern for processing with low properties, it is preferable to use a random arrangement.

  When creating the first pattern by randomly drawing a large number of dots over the entire range of the image to be created, as means for randomly drawing a large number of dots, for example, an image having a width WX and a height WY can be used. On the other hand, by generating a pseudo random number sequence R [n] that takes a value from 0 to 1, for example, the x coordinate of the dot center is WX × R [2 × m−1], and the y coordinate is WY × R [2 × m. ] To generate a large number of dots. Here, n and m are both natural numbers. As a method of generating a pseudo-random number sequence, any pseudo-random number generation can be used as long as it has a sufficient period length corresponding to the number of dots to be distributed, such as a linear congruential method, a Knuth random number generator subtraction algorithm, Xorshift or Mersenne Twister. Can be used. Alternatively, the first pattern in which dots are randomly arranged may be created by hardware that generates a random number by thermal noise or the like, not limited to a pseudorandom number.

  The shape of the dot may be a circle such as a circle or an ellipse, or a polygon, and a number of dots having the same shape may be arranged, or a number of dots having two or more different shapes may be arranged. May be. Further, the size of the dots may be the same for all the dots, or may be different. Therefore, when the dots are round, the first pattern may be created by randomly arranging a large number of dots having one type of dot diameter (dot diameter), and a plurality of types of dot diameters may be used. A large number of dots may be randomly arranged.

  The average dot diameter of the dots constituting the first pattern (the average value of the dot diameters of all dots in the pattern) is not particularly limited, but when a bandpass filter is used, the dot diameter has a peak in the passband range. Since it is preferable to set so as not to have a peak in the low spatial frequency region below the passband range, it is usually 4 to 50 μm, preferably 16 to 32 μm. When the average dot diameter exceeds 50 μm, a lot of low spatial frequency components that affect glare are included, and shading unevenness tends to occur in the created second pattern. On the other hand, if the average dot diameter of the dots constituting the first pattern is too small and the amplitude of the extracted spatial frequency component is small when the band pass filter is applied, the randomness of the first pattern is impaired. Therefore, a preferable second pattern cannot be obtained. The average dot diameter is preferably larger than 0.5 × (1 / (2 × T)) using the spatial frequency range upper limit value T given to the bandpass filter. As a result, when the dot filling rate is in a preferable range described later, it is easy to create a second pattern that sufficiently includes the spatial frequency component extracted by the band-pass filter and is less likely to cause shading unevenness.

  Similarly, when using a high-pass filter, it is preferable to set so that it has a dot diameter peak in the passband range and does not have a peak in a low spatial frequency region below the passband range. The average dot diameter of the dots constituting one pattern is usually 4 to 50 μm, preferably 6 μm or more, more preferably 8 μm or more, and preferably 32 μm or less, more preferably 30 μm or less, and even more preferably 12 μm. It is as follows. When the average dot diameter exceeds 50 μm, a lot of low spatial frequency components that affect glare are included, and shading unevenness tends to occur in the created second pattern.

  When the first pattern is created by arranging a large number of dots, the dot filling rate (occupied area of dots in the total area of the image) is preferably 20 to 80%, and preferably 20 to 70%. More preferably, it is more preferably 30 to 70%, still more preferably 30 to 60%, and particularly preferably 40 to 60% (for example, may be around 50%). . When the number of dots is extremely small and the filling rate of dots in the first pattern is less than 20%, the generated second pattern has unevenness including a concentric characteristic pattern, and a preferable random pattern is obtained. It tends to be impossible. Similarly, when the dot filling rate exceeds 80%, there is a tendency that a lot of unevenness consisting of a closed circular pattern tends to be seen, and the randomness is impaired.

  The first pattern may be created as vector format image data or raster format image data. In the case of the raster format, the first pattern can be created in an image format having an arbitrary bit depth such as 1 bit, 2 bits, or 8 bits. When creating the first pattern as raster format image data, it is preferable to create the first pattern at a high resolution so that details of the pattern can be drawn. A preferable resolution for the antiglare treatment is 6400 dpi or more, more preferably 12800 dpi or more.

  FIG. 1 is an enlarged view showing a preferable example of a first pattern which is formed by randomly arranging a large number of dots, which can be used in the antiglare treatment method for a transparent substrate and the method for producing an antiglare film of the present invention. . The first pattern shown in FIG. 1 is an 8-bit gray scale image, and a black circular area is a dot 1. In the present invention, the dot diameter is “dot diameter”, and the average dot diameter of all dots in the pattern is “average dot diameter”. The average dot diameter of the first pattern shown in FIG. 1 is 16 μm. The image resolution is 12800 dpi. That is, the size of one pixel corresponds to 2 μm in length and width. In the first pattern shown in FIG. 1, the image size is WX = 0.512 mm, WY = 0.512 mm, and the dot filling rate is about 50%. Moreover, the pseudorandom number which determines the center coordinate of a dot was produced | generated by mainly giving the numerical value 607 with respect to the SIMD oriented Fast Mersenne Twister program and SFMT ver1.3.3 which were mounted by the group of Hiroshima University.

  In addition, it is also preferable to use a pattern in which a lightness distribution is arranged, for example, a raster image whose density is determined by random numbers, as the first pattern. A pattern with a small regularity can be obtained by determining the density of each pixel (pixel) of the raster image using a random number or a pseudo-random number generated by a computer.

  The pixel density determination method will be described by taking as an example the case of using pseudo-random numbers that output real numbers in the range of 0 to 1. The number of gradations of the pixels may be arbitrary, but the gradation depth that is easy to handle is 1 bit, 8 bits, 16 bits, 24 bits, etc., preferably 8 bits (256 gradations: index 0 to 255). is there. For example, in the case of 8-bit gradation, an image can be generated by substituting PIXCEL [x, y] = R [x + y × ImageWidth] × 255 for PIXCEL [x, y] having a depth of 8 bits. . Here, x and y are pixel coordinates in the image, and ImageWidth is the image width of the x coordinate. In this example, an image having an average index of 127 to 128 is generated, but an image having a different average value may be generated by adding an offset.

  FIG. 2 is a diagram showing an example of a first pattern made up of raster images whose shades are determined by random numbers, and FIG. 3 is an enlarged view of a part thereof. The raster image shown in FIG. 2 is an 8-bit gradation image created by determining the brightness of each pixel by a pseudo-random number. Specifically, the raster image is a two-dimensional array PIXCEL [ It was created by substituting PIXCEL [x, y] = R [x + y × ImageWidth] × 255 for x, y]. Here, x and y are pixel coordinates in the image, and ImageWidth is the pixel width of the x coordinate. Random number generator subtraction of Knuth taking a value between 0.0 and 1.0 generated by Random class NextDouble method included in “.NET Framework 2.0 class library” developed by Microsoft Corporation as array R [] A pseudo-random number sequence by algorithm was used.

  The first pattern may be a two-dimensional array of discretized information generated in the same manner as the above raster image. In this case, pseudorandom numbers are used to determine the value of each element of the array.

  The form of the first pattern may be appropriately selected depending on, for example, a method for applying a high-pass filter or a band-pass filter, an input format required by a processing apparatus used for processing an uneven shape on a transparent substrate, and the like. Among them, a raster image whose density is determined by random numbers can be preferably used because it has an amplitude in a wide spatial frequency range. This is because it is easy to maintain the randomness of the first pattern regardless of the spatial frequency range extracted by a filter such as a high-pass filter or a band-pass filter.

FIG. 4 shows an example of a spatial frequency distribution obtained by converting a two-dimensional array obtained from a first pattern (random dot pattern) created by randomly arranging a number of dots into a spatial frequency domain by FFT, It is a figure which compares with an example of the spatial frequency distribution obtained by converting the two-dimensional arrangement | sequence obtained from the 1st pattern which consists of the raster image (random number raster image) which determined the shading into a spatial frequency domain by FFT, It shows the amplitude intensity in the region from 0 to 0.30 μm ⁻¹ . As shown in FIG. 4, the random dot pattern has higher amplitude intensity than the random number raster image, particularly in the region of the spatial frequency of 0.00 to 0.10 μm ⁻¹ . Note that FIG. 4 will be described in detail later.

(Create second pattern)
In the antiglare treatment method and the antiglare film manufacturing method of the transparent substrate of the present invention, the second pattern has a specific value of spatial frequency from the spatial frequency component included in the first pattern with respect to the first pattern. It is created by applying a filter that at least removes or reduces low spatial frequency components that are less than. In the present invention, the filter is a high-pass filter that removes or reduces only a low spatial frequency component whose spatial frequency is less than a specific value from the spatial frequency component included in the first pattern, or is included in the first pattern. By removing or reducing low spatial frequency components whose spatial frequency is less than a specific value, and removing or reducing high spatial frequency components whose spatial frequency exceeds a specific value, the spatial frequency component of a specific range A band-pass filter for extracting the signal can be preferably used. In general, the pattern includes a spatial frequency component corresponding to the change. A pattern that changes drastically or has a dense arrangement contains many components with a high spatial frequency, and a pattern that changes slowly or has a low arrangement has few components with a high spatial frequency. By applying a high-pass filter or a band-pass filter, removing or reducing a spatial frequency component in a specific range from a spatial frequency component included in the first pattern, that is, a low spatial frequency component that is a long-period component causing glare or the like Can do. By applying the high-pass filter or the band-pass filter, it is possible to reduce the low spatial frequency component in the second pattern, the third pattern, or the fourth pattern for imparting the uneven shape on the transparent substrate. Specifically, the creation of the second pattern by applying the high-pass filter or the band-pass filter to the first pattern can be performed by the following series of operations (1) to (3).

(1) Conversion to Spatial Frequency Domain First, in order to be able to extract a specific spatial frequency component from the spatial frequency component included in the first pattern (that is, remove or reduce the specific spatial frequency component), When one pattern is a raster image, the first pattern is converted into a floating-point type two-dimensional array g [x, y] into which values according to the lightness of each pixel are substituted as necessary. Here, x and y indicate positions on the orthogonal coordinates in the raster image. The two-dimensional array g [x, y] obtained in this way is included in the first pattern by applying means for obtaining various spatial frequency component magnitudes in the first pattern. A spatial frequency distribution indicating the spatial frequency component and the amplitude at each spatial frequency is obtained. As a means for obtaining the magnitude of the spatial frequency component, there are an optical technique, a mathematical technique, and the like. In particular, a mathematical calculation method using a computer is widely used. A mathematical method for obtaining the magnitude of the spatial frequency component is generally called Fourier transform. The Fourier transform can be performed by a discrete Fourier transform (hereinafter referred to as DFT) using a computer. Therefore, the conversion to the spatial frequency domain can be performed by applying a two-dimensional DFT to the two-dimensional array obtained from the first pattern using, for example, a computer.

  As the DFT algorithm, a generally known algorithm can be used. In particular, the Cooley-Tukey type algorithm can be suitably used because of its excellent calculation speed. The DFT based on the Boolean-Tukey type algorithm is also referred to as a fast Fourier transform (hereinafter referred to as FFT).

When the first pattern is created in the raster format, the raster format image data can be easily converted into the spatial frequency domain on the computer by using the DFT algorithm. When the first pattern is generated in the vector format and converted to the spatial frequency domain using the DFT algorithm, the image data converted into the raster format is converted from the vector format image data to the raster format. Is converted into a two-dimensional array g [x, y] on a computer. Here, x and y indicate positions on the orthogonal coordinates in the raster image. When the first pattern is created as a general gray scale image having, for example, 8-bit gradation, 255 is assigned to the white area and 0 is assigned to the black area. Using these values, image data is converted into a two-dimensional array G [f _x , f _y ] in the spatial frequency domain on the computer by DFT. Here, the f _x, respectively f _y, x-direction spatial frequency, y-direction spatial frequency. When the first pattern is given as a two-dimensional array of discretized information, it is converted into a two-dimensional array G [f _x , f _y ] in the spatial frequency domain on a computer by applying DFT to the first pattern. It goes without saying that it is possible.

  When DFT is used, a process of subtracting the average value PA of all elements of a two-dimensional array from each array element of the first pattern which is a two-dimensional array of discretized information or the first pattern converted to a two-dimensional array May be performed. For example, after the first pattern created as an 8-bit gray scale image having a value from 0 to 255 is converted into a two-dimensional array, the average value PA of the two-dimensional array is subtracted from each array element. Can be done. When an 8-bit gray scale image having a value from 0 to 255 is converted into a two-dimensional array, a spatial frequency spectrum having an amplitude at a spatial frequency of 0 may be obtained. This is because all elements constituting the two-dimensional array are positively biased. In the production of an antiglare treatment and an antiglare film to be applied to a transparent substrate, it is important to be able to grasp the characteristics of the surface unevenness imparted to the transparent substrate, but the amplitude at the spatial frequency of 0 is finally formed. It is not significant information for knowing the characteristics of the uneven shape. By performing the process of subtracting the total element average value PA of the two-dimensional array from each array element so that the amplitude becomes 0 at the spatial frequency 0, it becomes possible to easily grasp the characteristics of the finally formed uneven shape. .

  FIG. 5 is a diagram showing a two-dimensional spatial frequency distribution obtained by converting the two-dimensional array obtained from the first pattern shown in FIG. 1 into the spatial frequency domain by FFT. In FIG. 5, both the horizontal axis and the vertical axis indicate the spatial frequency. The point where both axes intersect is a point with a spatial frequency of 0, and the spatial frequency increases as the distance from the intersection (zero point) increases. In addition, the intensity of the amplitude at each spatial frequency is indicated by the color intensity, and the darker the color, the greater the amplitude.

As described above, two-dimensional information as shown in FIG. 5 is obtained by converting an image that is two-dimensional data into a spatial frequency domain by FFT. However, since the two-dimensional display does not have a good line-of-sight, in the following, when a spatial frequency distribution is shown, a one-dimensional space in which the horizontal frequency is the horizontal axis and the average value of the amplitude intensity at each spatial frequency is the vertical axis. The frequency distribution will be shown. The two-dimensional spatial frequency distribution shown in FIG. 5 is represented by a one-dimensional spatial frequency distribution in the above-described dotted line graph in FIG. That is, the dotted line graph in FIG. 4 is obtained by converting the two-dimensional array obtained from the first pattern shown in FIG. 1 into the spatial frequency domain by FFT (obtained as a result of decomposition into spatial frequency by FFT). It is a figure which shows a one-dimensional spatial frequency distribution. In FIG. 4, the horizontal axis indicates the spatial frequency, and the vertical axis indicates the average value of the amplitude intensity of the elements belonging to each spatial frequency. Here, the amplitude intensity, the absolute value of each element of a two-dimensional array _{| G [f x, f y} ] | means. Also, the average value is obtained by dividing the range of spatial frequencies 0 to fmax into 128, and averaging the elements of the two-dimensional array belonging to each divided spatial frequency range, where fmax is the highest spatial frequency obtained by FFT. Desired. Spatial frequency range element belongs can be determined by a value f _a which is calculated from f _x and f _y. It shows a calculation formula for fmax and f _a formula (A) and formula (B) is shown below.
^{_{fmax = (f x max 2 +}} f y max 2) 1/2 (A)
f _a = (f _x ² + f _y ² ) ^1/2 (B)
The maximum value of f _x max is f _x, f _y max denotes the maximum value of f _y.

  Even when the first pattern is created with sufficiently random pseudo-random numbers as in the graph shown by the dotted line in FIG. 4, the first pattern may have an amplitude peak at a specific spatial frequency. is there. When such an amplitude peak exists, a second pattern having a desired spatial frequency characteristic is determined depending on a spatial frequency lower limit value specified for a high-pass filter described later or a spatial frequency range upper limit value or lower limit value specified for a bandpass filter. Since there is a possibility that it cannot be obtained, it is preferable to correct the amplitude of each element so that the amplitude at each spatial frequency is equal or substantially equal in a specific spatial frequency range.

FIG. 6 is a diagram illustrating an example of a result of amplitude correction performed on the spatial frequency distribution indicated by the dotted line in FIG. The spatial frequency distribution before amplitude correction (same as that shown in FIG. 4) is indicated by a dotted line, and the spatial frequency distribution after amplitude correction is indicated by a solid line. In the spatial frequency distribution shown in FIG. 6, the amplitude of each element is approximately constant in the region from the spatial frequency 0 to about 0.30 μm ⁻¹ due to the correction. Thus, by keeping the amplitude constant in the spatial frequency domain that can be extracted by the high-pass filter or the band-pass filter, the second pattern created by applying the high-pass filter or the band-pass filter has a constant amplitude. It has a specific range of spatial frequency components. This is advantageous in controlling pattern characteristics generated by applying a high-pass filter or a band-pass filter. The amplitude correction is specifically performed using the corrected complex amplitude absolute value C using the following formula:
α = C / | A _org |
By multiplying the complex amplitude A _org by the real number α given by However, | A _org | must not be zero. Therefore, the above correction is possible in a range where | A _org | is a non-zero value.

(2) Application of high-pass filter or band-pass filter Next, an operation corresponding to the high-pass filter or band-pass filter is performed on the two-dimensional array in the spatial frequency domain obtained by DFT. By this operation, the low spatial frequency component included in the first pattern is removed or reduced.

  The high-pass filter is also referred to as a high-pass filter, Low-Cut Filter, and has a function of removing or reducing components below a specified frequency in the field of signal processing. The operation corresponding to the high-pass filter is to remove or reduce a low spatial frequency component having a spatial frequency lower than the spatial frequency range lower limit B ′ out of the spatial frequency components included in the first pattern, and to lower the lower limit B ′. This is an operation for extracting a spatial frequency component composed of the above spatial frequencies. More specifically, in the case of using the DFT, the array element (the real part of the complex amplitude) of the spatial frequency component lower than the range specified by the spatial frequency range lower limit B ′ for the array converted into the spatial frequency domain. , Each of the imaginary parts) is an operation of substituting 0 (the amplitude is 0), or multiplying the absolute value by a value sufficiently smaller than 1. Taking the performance of a filter generally called a high-pass filter as an absolute value sufficiently smaller than 1, for example, the absolute value is closer to zero than 0.5, the absolute value is closer to zero than 0.3, absolute Examples include numerical values whose values are closer to zero than 0.1, or numerical values whose absolute values are closer to zero than 0.01. In general, the closer the absolute value of the multiplied value is to zero (including zero), the more ideal the high-pass filter is.

  The value of the spatial frequency range lower limit B ′ is the starting point of the rise when the spatial frequency dependence of the transmission ratio corresponding to the high-pass filter rises abruptly at a certain spatial frequency as shown in FIG. 7, for example. Can be considered. On the other hand, when the transmission ratio rises gently, the value of the spatial frequency range lower limit B ′ is a spatial frequency indicating a half of the peak intensity of the transmission band. The same applies to the spatial frequency range upper limit value T and the spatial frequency range lower limit value B of the bandpass filter. The transmission ratios shown in FIG. 7 and FIGS. 8 to 14 described later indicate the absolute values of the values multiplied by the above-described elements. In the examples shown below, the operations corresponding to the band pass filter and the high pass filter were performed by multiplying each by a real number.

  In the spatial frequency band (transmission band) extracted by applying the high-pass filter, the transmission ratio of each spatial frequency component (ratio of the amplitude intensity after applying the high-pass filter to the amplitude intensity before applying the high-pass filter) is an example shown in FIG. Thus, it may be constant over the entire transmission band, or the value may be changed as in the example shown in FIG. Further, as in the example illustrated in FIG. 9, the transmission band may have a plurality of peaks.

  The band-pass filter is also called a band-pass filter, and has a function of passing an intended range of frequencies and removing or reducing other frequencies in the field of signal processing. The operation corresponding to the band pass filter is a spatial frequency lower than the lower limit B of the spatial frequency range among the spatial frequency components included in the first pattern in the spatial frequency distribution of the first pattern obtained above. A low spatial frequency component and a high spatial frequency component having a spatial frequency exceeding the spatial frequency range upper limit value T are removed or reduced, and a spatial frequency component having a spatial frequency in a specific range from the lower limit value B to the upper limit value T is obtained. More specifically, in the case of using DFT, which is an extraction operation, 0 is substituted for array elements not included in the range specified by the passing spatial frequency range upper limit value T and the spatial frequency range lower limit value B (The amplitude is set to 0) or an operation of multiplying a value sufficiently smaller than 1. The value sufficiently smaller than 1 is as described above.

  In the spatial frequency band (transmission band) extracted by application of the bandpass filter, the transmission ratio of each spatial frequency component (ratio of amplitude intensity after application of the bandpass filter to amplitude intensity before application of the bandpass filter) is shown in FIG. As shown in FIG. 11 (the shape of the transmission band peak has a rectangular shape), it may be constant over the entire transmission band, or as in the example shown in FIG. 11 (the shape of the transmission band peak is Gaussian). , The value may be changing. Also, the peak shape of the transmission band may be symmetrical with respect to the spatial frequency axis, or the example shown in FIG. 12 (a modified Gaussian shape in which the shape of the transmission band peak has different slopes on the right and left sides of the peak). As well as asymmetrical. Further, the transmission band peak may be composed of a plurality of peaks as in the example shown in FIGS. 13 and 14 (the transmission band peak consists of two peaks).

  FIG. 15 is a diagram illustrating an example of a two-dimensional spatial frequency distribution after applying a bandpass filter to the first pattern having the spatial frequency distribution illustrated in FIG. In FIG. 15, the horizontal axis, the vertical axis, and the color density represent the same meaning as in FIG. 5. As shown in FIG. 15, the operation corresponding to the bandpass filter removes the spatial frequency component in a specific range specified by the spatial frequency range upper limit value T and the spatial frequency range lower limit value B or reduces its amplitude intensity. Is done.

  Next, preferred ranges of the spatial frequency range lower limit value B ′ given to the high-pass filter and the spatial frequency range upper limit value T and the spatial frequency range lower limit value B given to the bandpass filter will be described. The low spatial frequency component removed or reduced by the high-pass filter or the band-pass filter is an average side of the image display device to which the anti-glare treatment-treated transparent substrate (anti-glare film or the like) obtained by the present invention is applied. About 1/10 of the pixel size (for example, when three colors of RGB are arranged side by side, the average pixel size of each side of RGB is the average value of the long side and the short side) A low spatial frequency component equal to or lower than the spatial frequency corresponding to the following cycle is preferable. Thereby, the glare in an image display apparatus can be suppressed effectively.

Specifically, a commercially available image display device is described as an example. For example, when applied to an image display device corresponding to a full high-definition (resolution: 1920 × vertical 1080 dots, etc.) having a diagonal of about 103 inches, a high pass is used. The maximum value of the spatial frequency of the low spatial frequency component removed or reduced by the filter or the bandpass filter, that is, the spatial frequency range lower limit value B ′ or the spatial frequency range lower limit value B is 0.01 μm ⁻¹ or more. preferable. In addition, when applied to an image display apparatus corresponding to a high-definition screen having a diagonal of about 50 inches (resolution horizontal 1366 × vertical 768 dots, etc.), the spatial frequency range lower limit B ′ or the spatial frequency range lower limit B is 0.02 μm. It is preferably ⁻¹ or more. From the same consideration, when applied to an image display device corresponding to a high-vision of about 32 inches diagonal, the spatial frequency range lower limit B ′ or the spatial frequency range lower limit B is preferably 0.03 μm ⁻¹ or more. . When applied to an image display device corresponding to a full high-definition having a diagonal of about 37 inches, the spatial frequency range lower limit B ′ or the spatial frequency range lower limit B is preferably 0.04 μm ⁻¹ or more. When applied to an image display apparatus corresponding to a high-vision of about 20 inches diagonal, the spatial frequency range lower limit B ′ or the spatial frequency range lower limit B is preferably 0.05 μm ⁻¹ or more. When applied to an image display device equivalent to full high vision with a diagonal of about 22 inches, the spatial frequency range lower limit B ′ or the spatial frequency range lower limit B is preferably 0.07 μm ⁻¹ or more. In this way, by appropriately adjusting the lower limit of the spatial frequency range given to the high-pass filter or the band-pass filter according to the resolution and size of the image display device to be applied, the low spatial frequency in an appropriate range for the image display device. The second, third, or fourth pattern in which the component is removed or reduced can be created, and by using this to process the concavo-convex shape, it is possible to realize a preferable anti-glare treatment with reduced glare. it can.

In the band-pass filter, the spatial frequency range upper limit value T is preferably 1 / (D × 2) μm ⁻¹ or less from the viewpoint of processability. Here, D (μm) is the resolution of the processing apparatus used when processing the concavo-convex shape on the transparent substrate. When the spatial frequency range upper limit T exceeds 1 / (D × 2) μm ⁻¹ , it may be difficult to impart the uneven shape on the transparent substrate with good process reproducibility. Since the processing reproducibility becomes better as the spatial frequency range upper limit T is smaller, the spatial frequency range upper limit T is more preferably 1 / (D × 4) μm ⁻¹ or less, and further preferably 1 /. (D × 6) μm ⁻¹ or less. In particular, when the spatial frequency range upper limit T is 1 / (D × 6) μm ⁻¹ or less, a concavo-convex shape can be formed on a transparent substrate with good processing reproducibility using a highly productive laser drawing apparatus. preferable. On the other hand, as the spatial frequency range upper limit value T increases, the second pattern having a finer structure is formed, and therefore, processing reproducibility tends to be difficult.

  The processing apparatus used when processing the concavo-convex shape on the transparent substrate may be a conventionally known apparatus such as a laser drawing apparatus or a precision lathe. When the resist is exposed using a laser drawing apparatus to form a concavo-convex shape, the spot diameter of the laser corresponds to the resolution D (μm). Further, when a concave and convex shape is formed using a precision lathe provided with a ball end mill having a hemispherical tip, a ball end mill having a tip radius of r (μm) is used to form a flat surface on the concave and convex surface after processing. In the case of processing the concavo-convex shape so that the angle formed by the surface at each position is within θ degrees (θ is, for example, 10 degrees), 2 × r ÷ (sin (θ ÷ 180 × π)) is This corresponds to a resolution D (μm). In addition, when processing a concavo-convex shape by producing a mold having a concavo-convex surface using the second pattern and transferring the concavo-convex surface of the mold onto the transparent substrate, the concavo-convex shape is formed on the transparent substrate. The processing apparatus used when processing is meant a processing apparatus used when producing a mold having an uneven surface.

In addition, in the band pass filter, in order to give an appropriate fine uneven surface shape to the transparent substrate, the reciprocal of the longest cycle length 1 / B which is the reciprocal of the spatial frequency range lower limit B and the reciprocal of the spatial frequency range upper limit T. The intermediate period length MainPeriod = (1 / B + 1 / T) / 2, which is intermediate between the shortest period length 1 / T, is preferably in the range of 6 μm to 33 μm. MainPeriod corresponds to the average value of the period length (1 ÷ T) μm corresponding to the spatial frequency range upper limit value T given to the bandpass filter and the period length (1 ÷ B) μm corresponding to the spatial frequency range lower limit value B. . When MainPeriod exceeds 33 μm, it is difficult to form a fine uneven surface shape having a spatial frequency lower than 0.10 μm ^{−1 in} processing of the uneven shape on the transparent substrate, and the antiglare property cannot be effectively expressed. In addition, when MainPeriod is less than 6 μm, a fine uneven surface shape having a spatial frequency of less than 0.01 μm ⁻¹ may be formed in the processing of the uneven shape on the transparent substrate. When applied to a fine image display device (for example, when the obtained antiglare film is disposed on the surface of a high definition image display device), glare may occur.

  As described above, a main purpose of applying a filter such as a high-pass filter or a band-pass filter is a pattern (for example, a second, third, or fourth pattern, which will be described later) used to finally process the uneven shape. Is to remove or reduce a low spatial frequency component consisting of a spatial frequency lower limit B ′ or a spatial frequency lower than B.

(3) Generation of second pattern Next, spatial frequency information obtained by performing an operation corresponding to a high-pass filter or a band-pass filter is converted into a two-dimensional array by inverse discrete Fourier transform (IDFT), Based on this two-dimensional array, a second pattern is generated. As the IDFT algorithm, a generally known algorithm can be used as in the case of the DFT. The second pattern can have various bit depths, such as 8 bits, 16 bits, 32 bits, and 64 bits.

FIG. 16 is an enlarged view showing an example of a second pattern created by applying a bandpass filter to the first pattern shown in FIG. FIG. 16 is 12800 dpi image data as in FIG. The spatial frequency range lower limit B and the spatial frequency range upper limit T given to the bandpass filter are 0.043 μm ⁻¹ and 0.059 μm ⁻¹ , respectively. Further, 2 × (T−B) / (T + B) is 0.30.

  When generating the second pattern, the maximum value and the minimum value of the two-dimensional array obtained by the IDFT are respectively set to the maximum value and the minimum value defined by the bit depth of the second pattern to be generated. You may convert and substitute so that it may correspond. In other words, when the maximum value of the two-dimensional array element calculated by IDFT is Imax and the minimum value is Imin, when the element value Ix is converted to an 8-bit (0-255) pattern, it is assigned to each pixel of the pattern. Is calculated by 255 × (Ix−Imin) ÷ (Imax−Imin). The image data shown in FIG. 16 is obtained by performing such conversion.

  The example of the method for creating the second pattern by applying the high-pass filter or the band-pass filter using DFT has been described above, but the second pattern can be created by other methods. For example, the second pattern can also be obtained by using a plate in which openings are arranged as the first pattern and performing Fourier transform on the plate using an optical technique. More specifically, a spatial frequency filtering optical system composed of two lenses having the same focal point is prepared, and the first pattern is arranged on the focal plane of the first lens. At this time, the spatial frequency distribution of the image is obtained on the plane (Fourier plane) where the focal points of the two lenses coincide. In this Fourier plane, a spatial frequency in a desired range can be transmitted by spatially changing the light transmittance.

  The filtered output image is obtained on the focal plane opposite to the Fourier plane of the second lens. For example, when the plate is arranged so that only the central part of the aperture is transmitted through the Fourier plane, only the low spatial frequency component of the image is obtained as the output image. On the contrary, if the central part of the opening is shielded, only the high spatial frequency component is obtained as an output image. Therefore, by shielding the central portion and its peripheral portion on the Fourier plane, a second pattern having a target spatial frequency distribution can be obtained on the focal plane on the opposite side of the second lens.

(Conversion to discretized information and creation of third pattern)
In the present invention, it is preferable to create a pattern converted into discretized information from the second pattern obtained as described above. By making the pattern converted into discretized information, it is possible to obtain a pattern that is preferably applied to a processing apparatus used to process the concavo-convex shape. For example, when the process of processing the concavo-convex shape on the transparent substrate, which will be described later, includes resist work using a laser drawing apparatus or NC processing (Numerical Control Machining), the patterns used for these are multivalued such as binarization. It is preferable that In particular, when the step of processing the concavo-convex shape on the transparent substrate described later includes a resist work using a laser drawing apparatus or the like, the second pattern is converted into information discretized in two stages, that is, two It is preferable to convert it into a digitized pattern. This is because a resist pattern is generated by the binary value of whether or not the laser is irradiated. By binarizing the second pattern, an image applicable to a laser drawing apparatus or the like can be generated.

  The “discretized information” is also generally referred to as digital data, and the information handled on the computer is in most cases discretized information. Examples of discretized information include image data that can be handled on a computer such as bitmap data; and floating point numbers having various bit depths such as 128 bits, 64 bits, 32 bits, 16 bits, or the like, or Examples include signed or unsigned integers.

  "Conversion to discretized information" means converting a continuous function into a discrete representation, converting analog data into digital data, or being discretized being expressed in more stages It means converting information into information expressed with a smaller number of steps, and includes converting a digital signal into a digital signal expressed with a smaller bit depth. Examples of conversion to discretized information include, for example, discretely expressing a cosine function that is a continuous function, and information expressed in 32-bit floating point having a larger number of stages, For example, conversion to an 8-bit integer having a small number of bits is possible.

  In the present invention, since the second pattern obtained by applying the high-pass filter or the band-pass filter has high continuity, when obtaining a multi-valued pattern, particularly a binarized pattern, a specific pattern is obtained. It is preferable to apply a high-pass filter or a band-pass filter under conditions to multi-value the obtained second pattern, or to multi-value the second pattern by a specific method. Hereinafter, the multi-value quantization method preferably used in the present invention will be described with reference to examples.

(1) Binarization by threshold method As a method of binarizing the second pattern obtained by applying the bandpass filter, the threshold method can be preferably used. In the threshold method, a specific threshold is set for the gray scale index (lightness value), and white (or black) is given to pixels exceeding the threshold, and black (or white) is given to pixels below the threshold. This is a method of binarization.

In binarization by the threshold method of the second pattern obtained by application of the bandpass filter, the spatial frequency range lower limit B and the spatial frequency range upper limit T given to the bandpass filter are expressed by the following equation (1):
0.20 <2 × (T−B) / (T + B) <0.80 (1)
It is preferable to satisfy the following formula (2):
0.30 ≦ 2 × (T−B) / (T + B) ≦ 0.70 (2)
It is more preferable to satisfy. 2 × (T−B) / (T + B) in the above formulas (1) and (2) is a numerical value that is an index of the range of the spatial frequency of the second pattern extracted by the band pass filter. That is, the larger the 2 × (T−B) / (T + B), the wider the spatial frequency range of the second pattern, and the smaller the 2 × (T−B) / (T + B), the narrower the spatial frequency range of the second pattern.

  FIG. 17 shows the maximum value of the autocorrelation coefficient of the pattern obtained by binarizing the 2 × (T−B) / (T + B) value and the second pattern obtained by applying the bandpass filter by the threshold method. It is a figure which shows the relationship. The maximum autocorrelation coefficient means the maximum value of the autocorrelation coefficient. The autocorrelation coefficient is based on Wiener Hinting's theorem, the second pattern is converted into a two-dimensional array in the spatial frequency domain by two-dimensional Fourier transform, the coefficient of each element is squared, and this is further subjected to inverse Fourier transform It is obtained by applying. The autocorrelation coefficient maximum value is a numerical value that serves as an index indicating the strength of autocorrelation with respect to the translation of itself. Therefore, the higher the autocorrelation coefficient maximum value, the more likely the uneven shape processed on the transparent base material is to be continuous, and the shorter the periodic length of the uneven shape, the more visually. A unique periodicity is easily felt. Note that the autocorrelation coefficient maximum value shown in FIG. 17 is the autocorrelation coefficient maximum value in a range where the moving distance is 20 μm or more.

  As shown in FIG. 17, the maximum value of the autocorrelation coefficient increases extremely when 2 × (T−B) / (T + B) is 0.20 or less, while 2 × (T−B) / ( It can be seen that a relatively low value is maintained when T + B) is 0.30 or more. Therefore, in order to form a concavo-convex shape in which a specific periodicity is not felt on the transparent substrate, the value of 2 × (T−B) / (T + B) is preferably larger than 0.20, and 0.30 More preferably.

On the other hand, as the spatial frequency range of the second pattern becomes wider, a large number of components having different period lengths are added, so that the second pattern is isolated when the binarization processing by the threshold method is performed. As a result of examination, the tendency that small dots are likely to be generated became clear. FIG. 18 shows the number of isolated small dots generated in the pattern obtained by binarizing the value of 2 × (T−B) / (T + B) and the second pattern obtained by applying the bandpass filter by the threshold method. It is a figure which shows the relationship. In FIG. 18, “number of occurrences” means that the center spatial frequency is 0.05 μm ⁻¹ and the unevenness is formed on the transparent substrate in an image obtained by performing binarization processing by the threshold method on the second pattern. When the resolution D of a processing apparatus (laser drawing apparatus, etc.) used when processing a shape is 2 μm, the number of isolated small dots with which the length of one side of the continuous exposure range is 2 × D μm or less is determined. I mean. The presence of these isolated small dots with a small number of continuous elements can hinder sufficient processing reproducibility. The center spatial frequency is the reciprocal of the above MainPeriod.

  As shown in FIG. 18, when the number of isolated small dots is 2 × (T−B) / (T + B) is in the range of 0.80 or more, the number increases rapidly as the value increases. On the other hand, it can be seen that when 2 × (T−B) / (T + B) is 0.70 or less, a relatively low value is maintained. Therefore, in order to improve the processing reproducibility of the uneven shape, the value of 2 × (T−B) / (T + B) is preferably less than 0.80, preferably 0.70 or less. Is more preferable.

  From the above, in order to form an uneven shape with good processing reproducibility and no particular periodicity, the spatial frequency range lower limit B and the spatial frequency range upper limit T satisfy the above formula (1). It is preferable that the above formula (2) is satisfied. By applying a bandpass filter that satisfies the above formula (1), and preferably satisfies the above formula (2), without performing an isolated dot reduction process using a Monte Carlo method, which will be described later, by binarization by the threshold method, A pattern with good processing reproducibility can be obtained.

  Note that, after applying the band-pass filter, the amplitude intensity is different from the spatial frequency distribution in the range of the spatial frequency range lower limit B to the spatial frequency range upper limit T as in the case of the spatial frequency distribution of the first pattern. A process of increasing or decreasing the amplitude intensity may be performed so that the amplitude is preferably constant. By smoothly changing the amplitude intensity of the spatial frequency component, a smoother uneven shape can be obtained.

  Here, in the resist work, when the ratio of the exposure area is in the range of 30% to 70%, the suitability for etching and development is good. More preferably, it is in the range of 40% to 60%. In order for the pattern obtained by binarizing the second pattern by the threshold method to satisfy this condition, it is necessary to set the threshold appropriately. This can be achieved by analyzing the frequency distribution for each pixel of the obtained second pattern and binarizing the value with the cumulative frequency being the target ratio as a threshold value. Specifically, it is as follows, for example.

  FIG. 19 is a diagram showing a distribution of gray scale index accumulation rates obtained by analyzing a gray scale index histogram for the image data shown in FIG. According to the cumulative rate distribution shown in FIG. 19, it can be seen that the number of pixels having a gray scale index of 125 or less is 40%. FIG. 20 is an enlarged view of a pattern obtained by binarizing the image data shown in FIG. 16 by the threshold method using the gray scale index 125 as a threshold in consideration of the analysis result of the cumulative rate distribution. In the binarized second pattern shown in FIG. 20, the filling rate of the portion displayed in black (corresponding to the exposure area) is 40% by using the gray scale index 125 as a threshold value. . FIG. 21 shows a spatial frequency distribution obtained by converting the two-dimensional array obtained from the binarized second pattern shown in FIG. 20 into the spatial frequency domain by fast Fourier transform (FFT). As shown in FIG. 21, the binarized second pattern shown in FIG. 20 has a high spatial frequency component that reduces the low spatial frequency component involved in the occurrence of glare and reduces processing reproducibility. Since it has a reduced spatial frequency distribution, excellent anti-glare performance can be obtained by processing the concavo-convex shape on the transparent substrate using the binarized second pattern shown in FIG. Reduction of glare and suitability for processing are expected.

(2) Multi-value by dithering method As a method for multi-value such as binarization of the second pattern obtained by applying a high-pass filter or a band-pass filter, a dither method can be preferably used. In this case, an uneven shape is processed on the transparent substrate using a third pattern obtained by applying a dithering method to the second pattern. The dithering method is one of methods for converting analog data into digital data, or converting the bit rate and bit depth of digital data, and can be positioned as one method of digital signal processing. Various methods such as pattern dither method and error diffusion method are known to reduce the error bias when discretizing the signal by applying random signals such as rectangular probability density function and triangular probability density function. It has been.

  Among the above, in the present invention, a repetitive pattern that causes coloring due to moire or interference is unlikely to occur, and an effect of suppressing variation in local average brightness can be expected. Since there is a possibility that generation of fine patterns that are difficult to process can be suppressed, it is preferable to use an error diffusion method as the dithering method. The error diffusion method is characterized by diffusing an error that occurs during discretization to the periphery.

  The outline of the algorithm of the error diffusion method will be described by taking as an example the case of converting a grayscale bitmap of 8 bits 256 gradations into a monochrome bitmap of 1 bits 2 gradations. Assume that the brightness value of the pixel to be converted is 64. When this pixel is converted into a monochrome bit map of 1 bit and 2 gradations, it is necessary to convert it into white expressed with a brightness value of 255 or black expressed with a brightness value of 0 with 8 bits. Usually, it will be converted to a closer value. Accordingly, a pixel having a lightness value of 64 is closer to 0 than 255, and is therefore converted to a value corresponding to 0 (ie, black). At this time, a lightness value error of −64 occurs in the converted image when compared with an 8-bit gradation image. This means that the total brightness of the image has decreased by 64. In the error diffusion method, the lightness value of surrounding pixels is changed according to a predetermined weight so as to cancel out the lightness value error of −64. Binarization is performed by repeating such an operation for all pixels.

  Regarding the weighting method, several matrixes that are preferable in the field of image processing are known. For example, Floyd &Steinberg; Jarvis, Judis and Nink; Stucki; Burks; Stevenson &Arche; Sierra 3 Line; Sierra 2 Line; Sierra Filter Lite and the like are known as matrices having preferable weights.

  FIG. 22 is a diagram for explaining the weighting of the diffusion of the conversion error in the above exemplified matrix. As an example of the matrix, Floyd & Steinberg will be described as an example. The pixel A is a pixel to be converted. As in the above example, when the pixel A conversion (the conversion from the lightness value 64 to 0) causes a lightness value error of −64 in the converted image, the lightness value error is canceled out. The brightness values of four adjacent pixels are changed with a weight of 7: 1: 5: 3. That is, the brightness values of four adjacent pixels are increased by (7/16) × 64, (1/16) × 64, (5/16) × 64, and (3/16) × 64, respectively. Note that a pixel B with hatched hatching indicates a pixel for which binarization processing has been completed. A pixel described as “0” is a pixel having a weight of zero that does not diffuse an error.

Examples of the third pattern obtained by applying the error diffusion method according to the matrix shown in FIG. 22 to the second pattern obtained by applying the bandpass filter are shown in FIGS. Each of the third patterns shown in FIGS. 23 to 30 is created from the second pattern shown in FIG. 31 obtained as an 8-bit grayscale image, and consists of 1-bit monochrome image data. More specifically, the third pattern shown in FIGS. 23 to 30 is a 0 to 1 generated by Knuth's random number generator subtraction algorithm using a 1.024 mm square 8-bit bitmap image at a resolution of 12800 dpi. For the first pattern created using a pseudo-random number sequence having values, the spatial frequency range lower limit value B and the spatial frequency range upper limit value T are represented by the following formulas (I) and (II):
B = 1 / (MainPeriod * (1 + BandWidth / 100)) (I)
T = 1 / (MainPeriod * (1-BandWidth / 100)) (II)
The second pattern shown in FIG. 31 obtained by applying a band-pass filter whose transmission band peak has a rectangular shape is binarized by an error diffusion method using various matrices. is there. MainPeriod = 12 (μm) and BandWidth = 20 (%). 23 to 30 are enlarged views of a part of the generated third pattern in order to make it easier to grasp the characteristics of the image.

  FIG. 32 compares the spatial frequency distribution of the third pattern binarized by the error diffusion method according to various matrices shown in FIGS. 23 to 30 with the spatial frequency distribution of the pattern binarized by the threshold method. It is a figure to do. As shown in FIG. 32, when binarization is performed by the threshold method, the obtained pattern shows a relatively high amplitude intensity in the low spatial frequency region. On the other hand, when the error diffusion method is applied, the low spatial frequency component can be further reduced regardless of which matrix is adopted. Therefore, application of the error diffusion method makes it possible to realize an antiglare treatment and an antiglare film in which glare is more effectively suppressed. Note that the pattern binarized by the threshold method in FIG. 32 is compared to the second pattern shown in FIG. 31 with the intermediate value 127 as a threshold, a value larger than this as white, and a value less than this as black. It was created by binarization.

  As described above, by applying an error diffusion method according to a generally known error diffusion matrix as shown in FIG. 22, a third pattern having good spatial frequency characteristics can be obtained. However, the method of creating the third pattern binarized according to these error diffusion matrices is an isolated pixel (hereinafter referred to as an “isolated dot”) in which pixels of the same color do not exist as a group of a certain number or more. An isolated dot is conceptually similar to the above-mentioned “isolated small dot”, but its definition is different as described later. Here, the “isolated dot” refers to a lump (island) that is present in a binarized pattern and is composed of 16 or less continuous pixels of the same color. When the third pattern has many isolated dots, a lump (island) having a side of 4 pixels or less may exist. For example, a process including a CTP method or wet etching or a lathe process is used. Extremely high accuracy is required for uneven processing, and processing reproducibility may be hindered.

  FIG. 33 is a diagram for comparing the number of isolated dots generated when the third pattern is generated by applying an error diffusion method according to a generally known error diffusion matrix, compared with the case where the number of isolated dots is generated by the threshold method. The numerical values shown indicate the ratio to the number of isolated dots generated when a binarized pattern is created by the threshold method. As shown in FIG. 33, even in the Stevenson & Arche matrix where the frequency of isolated dots is the lowest, the number of occurrences is 27 times that of the threshold method, and reaches 155 times when the Floyd & Steinberg matrix is used. .

  As a result of intensive studies, the present inventors have found that it is preferable to use a matrix that does not include short-distance error diffusion as the error diffusion matrix in order to suppress the number of isolated dots generated.

  34 to 42 are diagrams illustrating examples of error diffusion matrices in which the diffusion distances are 1, 2, 3, 4, 5, 6, 3 + 4, 4 + 5, and 3 + 4 + 5, respectively. These figures show the weighting of the conversion error diffusion, as in FIG. The diffusion distance is a distance between a pixel whose brightness value is changed and a pixel to be converted in order to cancel a brightness value error caused by conversion of the pixel to be converted (pixel A) into white or black. “Diffusion distance 1” means that the pixel whose brightness value is to be changed and the pixel to be converted are adjacent to each other (see FIG. 34). “Diffusion distance 2” means that the second pixel counted from the pixel to be converted is a pixel whose brightness value is to be changed (one pixel is between the pixel whose brightness value is to be changed and the pixel to be converted). (Refer to FIG. 35). The same applies to a diffusion distance of 3 or more. Also, the “matrix of diffusion distance 3 + 4” in FIG. 40 is a combination of the “matrix of diffusion distance 3” shown in FIG. 36 and the “matrix of diffusion distance 4” shown in FIG. The same applies to FIGS. 41 and 42.

  Examples of the third pattern obtained by applying the error diffusion method according to the matrix shown in FIGS. 34 to 42 are shown in FIGS. 43 to 51, respectively. The second pattern used is the pattern shown in FIG. 43 to 51 are enlarged views of a part of the generated third pattern in order to make it easier to grasp the characteristics of the image. Furthermore, FIG. 52 compares the number of isolated dots generated when the third pattern is generated by applying the error diffusion method according to the error diffusion matrix shown in FIGS. FIG. The numerical values shown indicate the ratio to the number of isolated dots generated when a binarized pattern is created by the threshold method.

  As shown in FIG. 52, when the error diffusion distance is 1, the number of isolated dots is 247 times that of the threshold method, but the generated number decreases as the error diffusion distance is set larger. I understand that In particular, when the error diffusion distance exceeds 1, it can be seen that the number of isolated dots decreases rapidly. From the results shown in FIG. 52, in order to more effectively suppress the generation of isolated dots, the error diffusion distance should exceed 1 (that is, the conversion error is diffused to a range exceeding 1 pixel, and so on). Is preferably 2, or more, more preferably 3 or more. The upper limit of the error diffusion distance is not particularly limited, but is, for example, 6 or less. In particular, a pattern created using a matrix having an error diffusion distance of 3 or more has a wide processing range and is expected to have good processing suitability.

  53 shows the spatial frequency distribution of the third pattern of FIGS. 43 to 51 binarized by the error diffusion method according to the error diffusion matrix shown in FIGS. 34 to 42 and the space of the pattern binarized by the threshold method. It is a figure which compares with frequency distribution. The pattern binarized by this threshold method is the same as that in FIG. From FIG. 53, it can be seen that the amplitude of the low spatial frequency component can be reduced as compared with the threshold method when any error diffusion matrix is used.

(Creation of the fourth pattern)
A pattern converted into binarized information (binarized) by the threshold method or dithering method may include many isolated dots. In such a case, the fourth pattern may be created by further performing an operation of reducing isolated dots on the binarized pattern such as the third pattern. In this case, a concavo-convex shape is processed on the transparent substrate using the obtained fourth pattern. By performing an operation for reducing the number of isolated dots, it is possible to impart a concavo-convex shape on the transparent substrate with better process reproducibility. The binarized pattern used to create the fourth pattern may be binarized by a threshold method, or binarized by a dithering method such as an error diffusion method. Also good. However, as described above, when the second pattern is created by applying a bandpass filter that satisfies the above formula (1), and preferably satisfies the above formula (2), such an isolated dot reduction process is performed. It is not always necessary.

  As an operation for reducing the number of isolated dots, a method of moving black or white pixels, which are isolated dots present in a binarized pattern such as the third pattern, to a cluster (island) of the same color by the Monte Carlo method. It can be preferably used. The Monte Carlo method is a general term for a method of performing a simulation based on random numbers. The simplest method for processing isolated dots is to simply delete the isolated dots. However, when such a simple method is used in image processing, the average brightness value may change locally, which leads to an increase in low spatial frequency components. The Monte Carlo method is an effective method for processing isolated dots without affecting the average brightness locally. Hereinafter, a specific example of the processing method of isolated dots by the Monte Carlo method will be described with reference to FIG.

  First, it is determined whether or not the target pixel (pixel) is an “isolated dot”. The “isolated dot” in the specific example described here is different from the above definition, and the number of pixels (same color) at the same stage (same color) as the target pixel among the eight nearest neighboring pixels is two or less. Defined. For example, when the target pixel is black, it is determined as an isolated dot if the number of black pixels in the closest eight pixels is two or less. The same applies to white pixels. Next, the pixel determined to be an isolated dot is moved to a pixel selected by a random number from among the nearest free pixels.

  For example, in FIG. 54 (a), when the target pixel is black, only one pixel out of the nearest 8 pixels is black, so it is determined as an isolated dot, and the target pixel is an empty nearest 7 pixel. Among them, the pixel is moved to a pixel selected by a random number. In FIG. 54 (b), when the target pixel is black, two of the nearest eight pixels are black, so it is determined as an isolated dot, and the target pixel is the nearest six nearest pixels. , Moved to a pixel selected with a random number. In FIG. 54 (c), when the target pixel is black, three of the nearest eight pixels are black, so that it is not determined as an isolated dot and is not moved.

  By repeating the operation by the Monte Carlo method as described above, it is possible to effectively reduce isolated dots. When the operation by the Monte Carlo method is repeated about 10 to 60 times, for example, when the spatial frequency value of the spatial frequency component transmitted through the bandpass filter is between 3 and 6 pixels in terms of period length, A pattern that is hardly detected and is expected to have good processability can be obtained.

  FIGS. 55A to 55F are diagrams showing changes in the fourth pattern depending on the number of times the Monte Carlo method is applied. In the patterns shown in FIGS. 55A to 55F, the Monte Carlo method is performed 0, 4, 8, 20, 40, and 60 times with respect to the third pattern shown in FIG. 47 (diffusion distance 5), respectively. It is obtained by applying and processing isolated dots. FIG. 56 is a diagram showing the relationship between the number of times the Monte Carlo method is applied and the number of isolated dots generated. The isolated dot generation number ratio in FIG. 56 corresponds to the number of isolated dots generated when a binarized pattern is created from the second pattern shown in FIG. 31 by the threshold method, as in FIGS. Is the ratio. In this manner, by applying the repeated Monte Carlo method, it is possible to reduce isolated dots and create a fourth pattern that is expected to have better processing suitability.

  The above-described fourth pattern creation example uses the second pattern created by applying a bandpass filter to the first pattern. However, the fourth pattern created by applying a high-pass filter is used. Even in the case of using the pattern 2, as in the case of the bandpass filter, a low spatial frequency component is reduced by binarization and isolated dot reduction processing, and a fourth pattern having excellent processing suitability is obtained. Can do.

  Of the pattern creation methods used to process the concavo-convex shape on the transparent substrate shown above, the third pattern is applied to the second pattern by applying a dithering method (in particular, an error diffusion method). And the fourth pattern is created by applying the Monte Carlo method to this, even when the band-pass filter satisfying the above equation (1) is not applied when the second pattern is created. This is one of the preferred embodiments because it is possible to obtain a pattern with reduced frequency components and isolated dots.

(Processing uneven shapes using patterns)
In this step, any one of the patterns obtained as described above (the second pattern or a pattern obtained by converting (binarizing) this into information discretized in two stages by the threshold method, Or the fourth pattern) is used to process an uneven shape on the transparent base material, thereby imparting antiglare properties to the transparent base material. The processing apparatus used when processing the concavo-convex shape on the transparent substrate may be a conventionally known apparatus, and for example, a laser drawing apparatus, a laser processing apparatus, a precision lathe, or the like can be used. As the laser processing apparatus, for example, various processing apparatuses sold as laser markers, laser engraving machines, laser processing machines, and the like can be used.

  It is preferable that the processing of the concavo-convex shape on the transparent substrate is performed using a processing apparatus that performs processing based on the discretized information of the above-described pattern. Specific examples of the processing apparatus that performs processing based on the discretized information include various NC processing apparatuses such as a precision lathe, an automatic engraving apparatus, a laser processing apparatus, and a laser drawing apparatus. For example, when a laser drawing apparatus or the like is used as the processing apparatus, the discretized information is preferably information discretized in two stages.

  Further, when the pattern used for the uneven processing is composed of a two-dimensional array of discretized information, in the uneven processing performed based on the values stored in the two-dimensional array, depending on the characteristics of the processing device, these Values can be converted and used for processing. For example, in the case of a laser processing machine or a laser engraving machine, it may be read as the number of times of laser irradiation. In the case of a processing device that controls the depth of a cutting tool such as a precision lathe, the cutting tool may be converted into an amount corresponding to the amount of pressing of the cutting tool.

  The transparent substrate is not particularly limited as long as it is a member made of an optically transparent material. For example, in addition to a member made of a curable resin such as an ultraviolet curable resin, a resin material such as a thermoplastic resin, a glass substrate It may be. For example, by directly applying the anti-glare treatment of the present invention to the surface of a transparent substrate such as a glass substrate provided on the outermost surface of the image display device, the image display device can be anti-glare treated. Thereby, it is possible to obtain an image display device in which whitishness and glare are effectively suppressed while exhibiting excellent antiglare performance. Moreover, an anti-glare film can be obtained by using a resin film as a transparent substrate and processing an uneven | corrugated shape on this resin film by the method of this invention. By disposing the antiglare film obtained by the method of the present invention on the surface of the image display device, it is possible to obtain an image display device in which whitening and glare are effectively suppressed while exhibiting excellent antiglare performance. it can.

  In the anti-glare treatment method and the anti-glare film manufacturing method of the transparent substrate of the present invention, the fine uneven surface shape can be manufactured on the transparent substrate with higher accuracy and with higher processing reproducibility. Therefore, any one of the above patterns (the second pattern or a pattern obtained by converting (binarizing) this into information discretized in two stages by the threshold method, the third pattern, or the fourth pattern) It is preferable to include a step of producing a mold having an uneven surface (fine uneven surface shape) using a pattern, and transferring the uneven surface of the manufactured mold onto a transparent substrate. By removing the transparent base material having the concavo-convex surface transferred from the mold, a transparent base material (including an antiglare film) having a fine concavo-convex surface shape can be obtained.

  The transfer of the mold shape to the transparent substrate is preferably performed by an embossing method. Examples of the embossing method include a UV embossing method using a photocurable resin and a hot embossing method using a thermoplastic resin. Among these, the UV embossing method is preferable from the viewpoint of productivity.

  The UV embossing method forms a photocurable resin layer on the surface of a transparent substrate, and cures the photocurable resin layer while pressing the photocurable resin layer against the uneven surface of the mold so that the uneven surface of the mold is a photocurable resin. It is a method of transferring to a layer. Specifically, an ultraviolet curable resin is applied onto a transparent substrate, and the ultraviolet curable resin is irradiated with ultraviolet rays from the transparent substrate side while the coated ultraviolet curable resin is in close contact with the uneven surface of the mold. The mold resin is cured, and then the shape of the mold is transferred to the ultraviolet curable resin by peeling the transparent substrate on which the cured ultraviolet curable resin layer is formed from the mold.

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

  Moreover, the kind of ultraviolet curable resin in the case of using UV embossing method is not specifically limited, The commercially available appropriate thing can be used. It is also possible to use a resin that can be cured by visible light having a wavelength longer than that of ultraviolet rays by combining an ultraviolet curable resin with an appropriately selected photoinitiator. Specifically, polyfunctional acrylates such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate are used singly or as a mixture of two or more thereof and Irgacure 907 (manufactured by Ciba Specialty Chemicals). ), Irgacure 184 (manufactured by Ciba Specialty Chemicals), and a photopolymerization initiator such as Lucillin TPO (manufactured by BASF) can be suitably used.

  On the other hand, the hot embossing method is a method in which a transparent base material made of a thermoplastic resin is pressed against a mold in a heated state, and the uneven surface shape of the mold is transferred to a transparent support. The transparent base material used in the hot embossing method may be any material as long as it is substantially transparent. For example, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, triacetyl cellulose, norbornene compounds are used as monomers. A solvent cast film or an extruded film of a thermoplastic resin such as amorphous cyclic polyolefin can be used. These transparent resin films can also be suitably used as a transparent substrate for applying the ultraviolet curable resin in the UV embossing method described above.

<Manufacturing method of mold>
Below, the manufacturing method of the metal mold | die which can be used suitably for the anti-glare processing method of this invention and the manufacturing method of an anti-glare film is demonstrated. FIG. 57 is a diagram schematically showing a preferred example of the first half of the method for producing a mold of the present invention. FIG. 57 schematically shows a cross section of the mold in each step. The mold manufacturing method of the present invention includes [1] a first plating step, [2] a polishing step, [3] a photosensitive resin film forming step, [4] an exposure step, and [5] a development step. [6] Basically includes a first etching step, [7] a photosensitive resin film peeling step, and [8] a second plating step. Hereafter, each process of the manufacturing method of the metal mold | die of this invention is demonstrated in detail, referring FIG.

[1] First Plating Step In the mold manufacturing method of the present invention, first, copper plating or nickel plating is applied to the surface of the substrate used for the mold. Thus, by performing copper plating or nickel plating on the surface of the mold base, it is possible to improve the adhesion and gloss of chromium plating in the subsequent second plating step. In other words, as described above as the background art, when chrome plating is applied to the surface of iron, etc., or when chrome plating is applied again after forming irregularities on the chrome plating surface by the sandblast method or bead shot method, etc. The surface tends to be rough and fine cracks occur, making it difficult to control the uneven shape of the mold surface. On the other hand, such inconvenience can be eliminated by first performing copper plating or nickel plating on the substrate surface. This is because copper plating or nickel plating has a high covering property and a strong smoothing action, so that a flat and glossy surface is formed by filling minute irregularities and voids of the mold base. is there. Due to the characteristics of these copper plating or nickel plating, even if chromium plating is applied in the second plating step described later, the rough surface of the chromium plating that seems to be caused by minute irregularities and voids that existed on the substrate is eliminated. In addition, the occurrence of fine cracks is reduced due to the high coverage of copper plating or nickel plating.

  The copper or nickel used in the first plating step may be a pure metal, or may be an alloy mainly composed of copper or an alloy mainly composed of nickel. “Copper” means to include copper and copper alloy, and “nickel” means to include nickel and nickel alloy. Copper plating and nickel plating may be performed by electrolytic plating or electroless plating, respectively, but electrolytic plating is usually employed.

  When copper plating or nickel plating is performed, if the plating layer is too thin, the influence of the underlying surface cannot be completely eliminated. Therefore, the thickness is preferably 50 μm or more. Although the upper limit of the plating layer thickness is not critical, the upper limit of the plating layer thickness is preferably about 500 μm in view of cost and the like.

  In the metal mold manufacturing method of the present invention, examples of the metal material suitably used for forming the metal mold substrate include aluminum and iron from the viewpoint of cost. From the viewpoint of handling convenience, it is more preferable to use lightweight aluminum. The aluminum and iron here may be pure metals, respectively, or may be an alloy mainly composed of aluminum or iron.

  Moreover, the shape of the base material for metal mold | die may be an appropriate | suitable shape conventionally employ | adopted in the said field | area, for example, besides a flat form, a cylindrical or cylindrical roll may be sufficient. If a die is produced using a roll-shaped substrate, there is an advantage that the anti-glare treatment can be continuously performed and the anti-glare film can be produced in a continuous roll shape.

[2] Polishing Step In the subsequent polishing step, the surface of the substrate that has been subjected to copper plating or nickel plating in the first plating step described above is polished. It is preferable that the base material surface is grind | polished in the state close | similar to a mirror surface through the said process. This is because metal plates and metal rolls that serve as base materials are often subjected to machining such as cutting and grinding in order to achieve the desired accuracy, and as a result, machine marks remain on the base material surface. This is because even if copper plating or nickel plating is applied, those processed marks may remain, and the surface may not be completely smooth in the plated state. That is, even if a process described later is performed on the surface where such deep processed marks remain, unevenness such as processed marks may be deeper than the unevenness formed after each process is performed. Such effects may remain, and when an antiglare treatment is performed using such a mold or an antiglare film is produced, the optical characteristics may be unexpectedly affected. In FIG. 57 (a), a plate-shaped mold substrate 7 is subjected to copper plating or nickel plating on its surface in the first plating step (for the copper plating or nickel plating layer formed in this step). Further, a state in which the surface 8 is mirror-polished by a polishing process is schematically shown.

  There is no particular limitation on the method for polishing the surface of the substrate on which copper plating or nickel plating has been applied, and any of mechanical polishing, electrolytic polishing, and chemical polishing can be used. Examples of the mechanical polishing method include super finishing, lapping, fluid polishing, and buff polishing. As for the surface roughness after polishing, the center line average roughness Ra in accordance with the provisions of JIS B 0601 is preferably 0.1 μm or less, and more preferably 0.05 μm or less. If the centerline average roughness Ra after polishing is greater than 0.1 μm, the final unevenness of the mold surface may remain affected by the surface roughness after polishing. In addition, the lower limit of the center line average roughness Ra is not particularly limited, and there is no limit in particular because there is a natural limit from the viewpoint of processing time and processing cost.

[3] Photosensitive resin film forming step In the subsequent photosensitive resin film forming step, the photosensitive resin was dissolved in the solvent on the polished surface 8 of the mold substrate 7 that was mirror-polished by the polishing step described above. A photosensitive resin film is formed by applying as a solution, heating and drying. FIG. 57B schematically shows a state in which the photosensitive resin film 9 is formed on the polished surface 8 of the mold base 7.

  A conventionally known photosensitive resin can be used as the photosensitive resin. Examples of the negative photosensitive resin having a property of curing the photosensitive part include, for example, a monomer or prepolymer of an acrylate ester having an acrylic group or a methacrylic group in the molecule, a mixture of bisazide and a diene rubber, polyvinyl Cinnamate compounds and the like can be used. Further, as a positive photosensitive resin having such a property that a photosensitive part is eluted by development and only an unexposed part remains, for example, a phenol resin type or a novolac resin type can be used. Moreover, you may mix | blend various additives, such as a sensitizer, a development accelerator, an adhesiveness modifier, and a coating property improving agent, with a photosensitive resin as needed.

  When these photosensitive resins are applied to the polished surface 8 of the mold base 7, it is preferable to dilute and apply in an appropriate solvent in order to form a good coating film. As the solvent, cellosolve solvents, propylene glycol solvents, ester solvents, alcohol solvents, ketone solvents, highly polar solvents, and the like can be used.

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

[4] Exposure Step In the subsequent exposure step, the second pattern created by applying a high-pass filter or a band-pass filter to the first pattern described above or information discretized in two steps by the threshold method. The converted (binarized) pattern, the third pattern, or the fourth pattern is exposed on the photosensitive resin film 9 formed in the above-described photosensitive resin film forming step. The light source used in the exposure process may be appropriately selected according to the photosensitive wavelength and sensitivity of the coated photosensitive resin. For example, the g-line (wavelength: 436 nm) of the high-pressure mercury lamp, the h-line (wavelength: 405 nm) of the high-pressure mercury lamp. ), I line (wavelength: 365 nm) of high pressure mercury lamp, semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), YAG laser (wavelength: 1064 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength) 193 nm), F2 excimer laser (wavelength: 157 nm), or the like.

  In order to form the surface uneven shape with high accuracy in the mold manufacturing method of the present invention, it is preferable to expose the pattern on the photosensitive resin film in a precisely controlled manner in the exposure step. In the mold manufacturing method of the present invention, in order to accurately expose the pattern on the photosensitive resin film, the pattern is created on a computer based on image data or a two-dimensional array of discretized information. It is preferable to draw a pattern on the photosensitive resin film by laser light emitted from a computer-controlled laser head. When performing such laser drawing, a laser drawing apparatus for making a printing plate can be used. Examples of such a laser drawing apparatus include Laser Stream FX (manufactured by Sink Laboratory Co., Ltd.) and the like.

  FIG. 57C schematically shows a state in which the pattern is exposed to the photosensitive resin film 9. When the photosensitive resin film is formed of a negative photosensitive resin, the exposed region 10 undergoes a crosslinking reaction of the resin by exposure, and the solubility in a developing solution described later decreases. Therefore, the unexposed area 11 in the developing process is dissolved by the developer, and only the exposed area 10 remains on the substrate surface as a mask. On the other hand, in the case where the photosensitive resin film is formed of a positive photosensitive resin, the exposed region 10 is cut by bonding of the resin by exposure, and the solubility in a developer described later increases. Therefore, the area 10 exposed in the development process is dissolved by the developer, and only the unexposed area 11 remains on the substrate surface as a mask.

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

  A conventionally well-known thing can be used about the developing solution used for a image development process. For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n-butylamine and the like Secondary amines, tertiary amines such as triethylamine, methyldiethylamine, alcohol amines such as dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, etc. Examples include alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and piperidine; and organic solvents such as xylene and toluene.

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

  FIG. 57D schematically shows a state in which a development process is performed using a negative photosensitive resin for the photosensitive resin film 9. In FIG. 57 (c), the unexposed region 11 is dissolved by the developer, and only the exposed region 10 becomes the remaining mask 12 on the substrate surface. FIG. 57 (e) schematically shows a state in which a development process is performed using a positive photosensitive resin for the photosensitive resin film 9. In FIG. 57 (c), the exposed region 10 is dissolved by the developer, and only the unexposed region 11 becomes the remaining mask 12 on the substrate surface.

[6] First Etching Step In the subsequent first etching step, the mold base is mainly used in a portion where there is no mask, using the photosensitive resin film remaining on the mold base surface after the development step as a mask. The material is etched to form irregularities on the polished plated surface. FIG. 58 is a diagram schematically showing a preferred example of the latter half of the mold manufacturing method of the present invention. FIG. 58 (a) schematically shows a state in which the mold base 7 in the portion 13 where no mask is mainly etched by the first etching step. The mold base 7 below the mask 12 is not etched from the mold base surface, but etching from the portion 13 without the mask proceeds with the progress of etching. Therefore, in the vicinity of the boundary between the mask 12 and the portion 13 without the mask, the mold base 7 under the mask 12 is also etched. In the vicinity of the boundary between the mask 12 and the portion 13 without the mask, the die base material 7 below the mask 12 is also etched, which is hereinafter referred to as side etching. FIG. 59 schematically shows the progress of side etching. The dotted line 14 in FIG. 59 shows the surface of the mold base material that changes as the etching progresses in stages.

The etching process in the first etching step is usually performed using a ferric chloride (FeCl ₃ ) solution, a cupric chloride (CuCl ₂ ) solution, an alkali etching solution (Cu (NH ₃ ) ₄ Cl ₂ ), etc. Although it is performed by corroding the surface, a strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can also be used. Although the concave shape formed on the mold base material when the etching process is performed differs depending on the type of the base metal, the type of the photosensitive resin film, the etching technique, and the like, the etching amount is 10 μm. In the following cases, etching is performed approximately isotropically from the metal surface in contact with the etching solution. The etching amount here is the thickness of the base material to be cut by etching.

  The etching amount in the first etching step is preferably 1 to 50 μm. When the etching amount is less than 1 μm, the unevenness shape is hardly formed on the metal surface, and the die is almost flat, so that the antiglare property is not exhibited. In addition, when the etching amount exceeds 50 μm, the height difference of the concavo-convex shape formed on the metal surface becomes large, and in the image display device to which the antiglare film produced using the obtained mold is applied, it is white. There is a risk of injury. The etching process in the first etching step may be performed by one etching process, or the etching process may be performed twice or more. In the case where the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

[7] Photosensitive resin film peeling step In the subsequent photosensitive resin film peeling step, the remaining photosensitive resin film used as a mask in the first etching step is completely dissolved and removed. In the photosensitive resin film peeling step, the photosensitive resin film is dissolved using a peeling solution. As the stripper, the same developer as that described above can be used. When a negative photosensitive resin film is used by changing pH, temperature, concentration, immersion time, etc., the exposed portion is exposed. When the positive photosensitive resin film is used, the photosensitive resin film in the non-exposed portion is completely dissolved and removed. There is no particular limitation on the peeling method in the photosensitive resin film peeling step, and methods such as immersion development, spray development, brush development, and ultrasonic development can be used.

  FIG. 58B schematically shows a state where the photosensitive resin film used as the mask 12 in the first etching process is completely dissolved and removed by the photosensitive resin film peeling process. The first surface irregularities 15 are formed on the surface of the mold substrate by etching using the mask 12 made of a photosensitive resin film.

[8] Second plating step Subsequently, the surface unevenness shape is blunted by performing chromium plating on the formed uneven surface (first surface unevenness shape 15). In FIG. 58 (c), the chromium plating layer 16 is formed on the first surface uneven shape 15 formed by the etching process in the first etching step as described above, so that the first surface uneven shape 15 is formed. A state is shown in which a rough surface (chrome plated surface 17) is formed.

In the present invention, chrome plating is employed which has a glossy surface, a high hardness, a low coefficient of friction, and good release properties on the surface of a flat plate or a roll. The type of chrome plating is not particularly limited, but it is preferable to use a chrome plating that expresses a good gloss, so-called gloss chrome plating or decorative chrome plating. Chromium plating is usually performed by electrolysis, and an aqueous solution containing chromic anhydride (CrO ₃ ) and a small amount of sulfuric acid is used as the plating bath. By adjusting the current density and electrolysis time, the thickness of the chromium plating can be controlled.

  JP-A-2002-189106, JP-A-2004-45472, JP-A-2004-90187, and the like disclosed above employ chrome plating. Depending on the type of chrome plating, the surface is often roughened after plating, or many fine cracks are generated due to chrome plating. The optical properties (including glare film) proceed in an unfavorable direction. A mold having a rough plated surface is not suitable for antiglare treatment of a transparent substrate and production of an antiglare film. This is because the plating surface is generally polished after chrome plating in order to eliminate roughness, but as described later, polishing of the surface after plating is not preferable in the present invention. In the present invention, by applying copper plating or nickel plating to the base metal, such an inconvenience easily caused by chromium plating is solved.

  In the second plating step, it is not preferable to perform plating other than chromium plating. This is because plating other than chromium has low hardness and wear resistance, so that the durability as a mold is lowered, and unevenness is worn away during use or the mold is damaged. In the anti-glare treatment using such a mold and the anti-glare film obtained from the mold, there is a high possibility that sufficient anti-glare function cannot be obtained, and on a transparent substrate such as a transparent resin film. There is a high possibility that defects will occur.

  Further, the surface polishing after plating as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2004-90187 is also not preferable in the present invention. That is, it is preferable to use the concavo-convex surface subjected to chrome plating as the concavo-convex surface of the mold transferred onto the transparent substrate without providing a step of polishing the surface after the second plating step. By polishing, a flat part is generated on the outermost surface, which may lead to deterioration of optical characteristics, and since shape control factors increase, shape control with good reproducibility becomes difficult. Depending on the reason.

  In this way, in the mold manufacturing method of the present invention, a chrome plating is applied to the surface on which the fine surface irregularities are formed, whereby a mold having an irregular surface and a higher surface hardness can be obtained. . The bluntness of the irregularities at this time varies depending on the type of the base metal, the size and depth of the irregularities obtained from the first etching process, and the type and thickness of the plating. The greatest factor in controlling is the plating thickness. When the thickness of the chrome plating is thin, the effect of dulling the surface shape of the unevenness obtained before the chrome plating process is insufficient, and the antiglare obtained by transferring the uneven shape onto a transparent substrate such as a transparent film. The optical properties of the transparent substrate (such as an antiglare film) subjected to the treatment are not so good. On the other hand, when the plating thickness is too thick, productivity is deteriorated and a projection-like plating defect called a nodule is generated, which is not preferable. Therefore, the thickness of the chrome plating is preferably in the range of 1 to 10 μm, and more preferably in the range of 3 to 6 μm.

  The chromium plating layer formed in the second plating step is preferably formed to have a Vickers hardness of 800 or more, and more preferably 1000 or more. When the Vickers hardness of the chrome plating layer is less than 800, the durability when using the mold is reduced, and the decrease in hardness due to chrome plating is due to abnormalities in the plating bath composition, electrolysis conditions, etc. during the plating process. This is because the possibility of occurrence is high, and the possibility of undesirably affecting the occurrence of defects is also high.

  Moreover, in the manufacturing method of the metal mold | die of this invention, the uneven | corrugated surface formed by the 1st etching process is etched between the above-mentioned [7] photosensitive resin film peeling process and [8] 2nd plating process. It is preferable to include the 2nd etching process blunted by. In the second etching process, the first surface irregularities 15 formed by the first etching process using the photosensitive resin film as a mask are blunted by an etching process. By this second etching process, there is no portion with a steep surface inclination in the first surface irregularity shape 15 formed by the first etching process, and an anti-glare film such as an anti-glare film manufactured using the obtained mold. The optical properties of the transparent substrate subjected to the treatment change in a preferable direction. In FIG. 60, by the second etching process, the first surface unevenness shape 15 of the mold base 7 is blunted, the portion having a steep surface inclination is blunted, and the second surface unevenness having a gentle surface inclination is obtained. The state where the shape 18 is formed is shown.

Similarly to the first etching step, the etching process in the second etching step is usually ferric chloride (FeCl ₃ ) solution, cupric chloride (CuCl ₂ ) solution, alkaline etching solution (Cu (NH ₃ ) ₄ Cl ₂ ) or the like, and by corroding the surface, strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can also be used. The bluntness of the unevenness after the etching process varies depending on the type of the underlying metal, the etching technique, and the size and depth of the unevenness obtained by the first etching process. The largest factor in controlling the amount is the etching amount. The etching amount here is also the thickness of the base material to be cut by etching, as in the first etching step. If the etching amount is small, the effect of dulling the surface shape of the unevenness obtained by the first etching step is insufficient, and the antiglare treatment obtained by transferring the uneven shape onto a transparent substrate such as a transparent film The optical properties of the applied transparent substrate (such as an antiglare film) are not so good. On the other hand, when the etching amount is too large, the uneven shape is almost lost and the die is almost flat, so that the antiglare property is not exhibited. Therefore, the etching amount is preferably in the range of 1 to 50 μm, and more preferably in the range of 4 to 20 μm. Similarly to the first etching process, the etching process in the second etching process may be performed by one etching process, or the etching process may be performed twice or more. In the case where the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

  Since the transparent substrate subjected to the anti-glare treatment such as the anti-glare film obtained by the anti-glare treatment method and the anti-glare film manufacturing method of the present invention is formed with its fine uneven surface shape being accurately controlled, It exhibits sufficient antiglare properties, does not cause whiteness, does not cause glare even when placed on the surface of an image display device, and exhibits high contrast.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

<Examples 1-3 and Comparative Examples 1-2>
An aluminum roll having a diameter of 200 mm (A5056 according to JIS) was prepared by applying copper ballad plating to the surface. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was set to be about 200 μm. The copper plating surface was mirror-polished, and a positive photosensitive resin was applied to the polished copper plating surface and dried to form a photosensitive resin film.

  Subsequently, the following five types of patterns I to V were simultaneously exposed and developed on the photosensitive resin film with a laser beam. Laser light exposure and development were performed using Laser Stream FX (manufactured by Sink Laboratories).

(1) Pattern I (Example 1): A pattern in which unit patterns partially shown in FIG. 61 are repeatedly arranged. The unit pattern is a 32.768 mm square pattern generated with a resolution of 12800 dpi, and FIG. 61 is a 1.024 mm square cut out. The unit pattern shown in FIG. 61 has a lower spatial frequency range lower limit than the first pattern shown in FIG. 62, in which dots having an average dot diameter of 16 μm are randomly distributed at a density of 2000 pieces / mm ² . The value B is 0.040 μm ⁻¹ , the spatial frequency range upper limit T is 0.070 μm ⁻¹ [therefore, 2 × (T−B) / (T + B) = 0.55], and the transmission band The peak is obtained by applying a bandpass filter having an asymmetric shape with a steep slope on the low spatial frequency side once, and then binarizing the obtained second pattern by the threshold method It is. The unit pattern obtained had a spatial frequency range lower limit B of 0.047 μm ⁻¹ and a spatial frequency range upper limit T of 0.067 μm ⁻¹ .

(2) Pattern II (Example 2): A pattern in which unit patterns partially shown in FIG. 63 are repeatedly arranged. The unit pattern is a 32.768 mm square pattern generated at a resolution of 12800 dpi, and FIG. 63 is a 1.024 mm square cut out. The unit pattern shown in FIG. 63 applies the same bandpass filter as used in the pattern I once to the first pattern partially shown in FIG. 62, and then the obtained second pattern. Is obtained by repeatedly applying the same bandpass filter 9 times. The unit pattern obtained had a spatial frequency range lower limit B of 0.047 μm ⁻¹ and a spatial frequency range upper limit T of 0.067 μm ⁻¹ .

(3) Pattern III (Example 3): A pattern in which unit patterns partially shown in FIG. 64 are repeatedly arranged. The unit pattern is a 32.768 mm square pattern generated with a resolution of 12800 dpi, and FIG. 64 is a 1.024 mm square cut out. The unit pattern shown in FIG. 64 applies the same bandpass filter as used in the pattern I once to the first pattern partially shown in FIG. 62, and then the obtained second pattern. Is binarized by the threshold method, and the same bandpass filter is further applied 19 times repeatedly. The unit pattern obtained had a spatial frequency range lower limit B of 0.047 μm ⁻¹ and a spatial frequency range upper limit T of 0.067 μm ⁻¹ .

(4) Pattern IV (Comparative Example 1): A pattern in which unit patterns partially shown in FIG. 65 are repeatedly arranged. The unit pattern is a 20.944 mm square pattern generated at a resolution of 12800 dpi, and FIG. 65 is a 1.024 mm square cut out. The unit pattern shown in FIG. 65 was created by randomly distributing dots having an average dot diameter of 16 μm at a density of 1419 pieces / mm ² .

(5) Pattern V (Comparative Example 2): A pattern obtained by repeatedly arranging unit patterns partially shown in FIG. The unit pattern is a 20.944 mm square pattern generated at a resolution of 12800 dpi, and FIG. 66 is a 1.024 mm square cut out. The unit pattern shown in FIG. 66 was created by randomly distributing dots having an average dot diameter of 16 μm at a density of 1419 pieces / mm ² .

  The above five types of patterns I to V were simultaneously exposed on the photosensitive resin film with a laser beam and developed, and then subjected to a first etching treatment with a cupric chloride solution. The etching amount at that time was set to 3 μm. The photosensitive resin film was removed from the roll after the first etching treatment, and the second etching treatment was performed again with cupric chloride solution. The etching amount at that time was set to 10 μm. Thereafter, chromium plating was performed to produce a mold. At this time, the chromium plating thickness was set to 4 μm.

A photocurable resin composition GRANDIC 806T (manufactured by Dainippon Ink & Chemicals, Inc.) is dissolved in ethyl acetate to obtain a 50% strength by weight solution. Further, a photopolymerization initiator, Lucillin TPO (manufactured by BASF). Chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) was added in an amount of 5 parts by weight per 100 parts by weight of the curable resin component to prepare a coating solution. This coating solution was applied onto a triacetyl cellulose (TAC) film having a thickness of 80 μm so that the coating thickness after drying was 10 μm, and was dried in a dryer set at 60 ° C. for 3 minutes. The dried film was brought into close contact with the uneven surface of the previously obtained mold by pressing with a rubber roll so that the photocurable resin composition layer was on the mold side. In this state, light from a high-pressure mercury lamp with an intensity of 20 mW / cm ² was irradiated from the TAC film side so that the amount of light in terms of h-line was 200 mJ / cm ² to cure the photocurable resin composition layer. Thereafter, the TAC film is peeled off from the mold together with the cured resin, and is composed of a laminate of the cured resin having the irregularities on the surface and the TAC film, and has a transparent surface shape having five types of irregularities corresponding to the patterns I to V. An antiglare film was produced.

<Example 4>
A mold is produced in the same manner as in Example 1 except that a pattern in which unit patterns partially shown in FIG. 67 are repeatedly arranged is exposed and developed with a laser beam on the photosensitive resin film over one roll. Further, an antiglare film was produced in the same manner as in Example 1. The same operation was performed twice to obtain a total of two antiglare films. The unit pattern shown in FIG. 67 is a 32.768 mm square pattern generated at a resolution of 12800 dpi, and FIG. 67 is a 1.024 mm square cut out.

The unit pattern shown in FIG. 67 creates a second pattern by applying a bandpass filter to the first pattern to create a second pattern, and then binarizing it by applying an error diffusion method. Furthermore, it is the 4th pattern produced by applying the Monte Carlo method 60 times repeatedly. The first pattern used is an 8-bit bitmap image of 32.768 mm square with a resolution of 12800 dpi, and PIXCEL [x, y] for a two-dimensional array PIXCEL [x, y] having an 8-bit depth. = R [x + y × ImageWidth] × 255. Here, x and y are pixel coordinates in the image, and ImageWidth is the pixel width of the x coordinate. As an array R [], a pseudo-random number sequence by a random number generator subtraction algorithm of Knuth that takes a value between 0.0 and 1.0 generated by a Random class NextDouble method included in ".NET Framework 2.0 class library" Using. The bandpass filter has a spatial frequency range lower limit B of 0.045 μm ⁻¹ and a spatial frequency range upper limit T of 0.080 μm ⁻¹ [therefore, 2 × (T−B) / (T + B) = 0.56], a band-pass filter having an asymmetrical shape in which the transmission band peak has a steeper slope on the low spatial frequency side was used. As the error diffusion matrix, the error diffusion matrix having a diffusion distance of 3 shown in FIG. 36 and the error diffusion matrix having a diffusion distance of 4 shown in FIG. 37 are combined at a ratio of 0.4: 0.6. (Fig. 36 x 0.4 + Fig. 37 x 0.6) was used. The spatial frequency range lower limit B of the unit pattern shown in FIG. 67 was 0.045 μm ⁻¹ , and the spatial frequency range upper limit T was 0.086 μm ⁻¹ .

  68 shows the spatial frequency distribution of the unit pattern used in Examples 1-3, FIG. 69 shows the spatial frequency distribution of the unit pattern used in Comparative Examples 1-2, and FIG. 69 shows the spatial frequency distribution of the unit pattern used in Example 4. Is shown in FIG.

<Example 5>
An aluminum roll having a diameter of 200 mm (A5056 according to JIS) was prepared by applying copper ballad plating to the surface. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer was set to be about 200 μm. The copper plating surface was mirror-polished, and a positive photosensitive resin was applied to the polished copper plating surface and dried to form a photosensitive resin film.

  Subsequently, a pattern in which unit patterns partially shown in FIG. 71 were repeatedly arranged was exposed on a photosensitive resin film with a laser beam and developed. Laser light exposure and development were performed using Laser Stream FX (manufactured by Sink Laboratories). The unit pattern shown in FIG. 71 is a 32.768 mm square pattern generated at a resolution of 12800 dpi, and FIG. 71 is a 1.024 mm square cut out.

The unit pattern shown in FIG. 71 creates a second pattern by applying a band-pass filter to the first pattern to create a second pattern, and then binarizing it by applying an error diffusion method. Furthermore, it is the 4th pattern produced by applying the Monte Carlo method 60 times repeatedly. The first pattern used is an 8-bit bitmap image of 32.768 mm square with a resolution of 12800 dpi, and PIXCEL [x, y] for a two-dimensional array PIXCEL [x, y] having an 8-bit depth. = R [x + y × ImageWidth] × 255. Here, x and y are pixel coordinates in the image, and ImageWidth is the pixel width of the x coordinate. As an array R [], a pseudo-random number sequence by a random number generator subtraction algorithm of Knuth that takes a value between 0.0 and 1.0 generated by a Random class NextDouble method included in ".NET Framework 2.0 class library" Using. The bandpass filter has a spatial frequency range lower limit B of 0.055 μm ⁻¹ and a spatial frequency range upper limit T of 0.100 μm ⁻¹ [therefore, 2 × (T−B) / (T + B) = 0.58], a band-pass filter having a transmission band peak shape of a Gaussian function type was used. As the error diffusion matrix, the error diffusion matrix having a diffusion distance of 4 shown in FIG. 37 and the error diffusion matrix having a diffusion distance of 5 shown in FIG. 38 are combined at a ratio of 0.9: 0.1. (FIG. 37 × 0.9 + FIG. 38 × 0.1) was used. The spatial frequency range lower limit B of the unit pattern shown in FIG. 71 was about 0.055 μm ⁻¹ , and the spatial frequency range upper limit T was about 0.100 μm ⁻¹ . FIG. 72 shows the spatial frequency distribution of the unit pattern shown in FIG.

  Then, the 1st etching process was performed with the cupric chloride liquid. The etching amount at that time was set to 5 μm. The photosensitive resin film was removed from the roll after the first etching treatment, and the second etching treatment was performed again with cupric chloride solution. The etching amount at that time was set to 8 μm. Thereafter, chromium plating was performed to produce a mold. At this time, the chromium plating thickness was set to 4 μm.

A photocurable resin composition GRANDIC 806T (manufactured by Dainippon Ink & Chemicals, Inc.) is dissolved in ethyl acetate to obtain a 50% strength by weight solution. Further, a photopolymerization initiator, Lucillin TPO (manufactured by BASF). Chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) was added in an amount of 5 parts by weight per 100 parts by weight of the curable resin component to prepare a coating solution. This coating solution was applied onto a triacetyl cellulose (TAC) film having a thickness of 80 μm so that the coating thickness after drying was 10 μm, and was dried in a dryer set at 60 ° C. for 3 minutes. The dried film was brought into close contact with the uneven surface of the previously obtained mold by pressing with a rubber roll so that the photocurable resin composition layer was on the mold side. In this state, light from a high-pressure mercury lamp with an intensity of 20 mW / cm ² was irradiated from the TAC film side so that the amount of light in terms of h-line was 200 mJ / cm ² to cure the photocurable resin composition layer. Thereafter, the TAC film was peeled off from the mold together with the cured resin to produce a transparent antiglare film comprising a laminate of the cured resin having irregularities on the surface and the TAC film.

  About the anti-glare film obtained in Examples 1-5 and Comparative Examples 1-2, the evaluation test shown below was done.

(1) Evaluation of glare The glare was evaluated by the following method. First, a photomask was prepared in which unit cell 60 patterns regularly arranged in a range of about 40 mm × about 25 mm as shown in a plan view in FIG. In the unit cell 60, a key-shaped chrome light shielding pattern 61 having a line width of 10 μm is formed on a transparent substrate, and a portion where the chrome light shielding pattern 61 is not formed is an opening 62. Such a photomask was given a “resolution name” [unit: ppi (pixel per inch)] according to the dimensions of the unit cell. For example, the unit cell length × unit cell width of a photomask having a resolution of 90 ppi is 282 μm × 94 μm, and the opening length × opening width is 272 μm × 84 μm. Such unit cells were manufactured based on the numerical values in Table 1, and a total of 10 patterns of photomasks were prepared in a resolution range of 90 to 180 ppi.

  Next, as shown in FIG. 73 (b), the chrome light-shielding pattern 61 of the photomask 63 is placed on the light box 65 (the light 66 is installed in the light box), and the thickness is 1.1 mm. A sample in which an antiglare film 70 is bonded to a glass plate 67 with an adhesive having a thickness of 20 μm is placed on a photomask 63 and visually observed from a place (visual observation place 69) about 30 cm away from the sample. The presence or absence was subjected to sensory evaluation. This evaluation was performed for each of the prepared photomasks having different resolution names.

  In the above evaluation, depending on the characteristics of the antiglare film, glare is observed in a photomask having a resolution resolution or higher. The glare was evaluated from the resolution call at this time. A method of discriminating the evaluation numerical value will be described with a specific example.

  First, in the sensory evaluation, when strong glare is observed in a photomask having a resolution nominal of 90 ppi, and no glare is observed in a photomask having a resolution nominal of 80 ppi, 80 ppi is given as an evaluation of the glare. However, depending on the characteristics of the antiglare film, there is a state where only weak glare is observed in a photomask having a resolution of 90 ppi. In order to distinguish such a state from the state described above, when only such a weak glare occurs, a resolution of the photomask used for evaluation is given as 85 ppi, which is an intermediate value between 80 ppi and 90 ppi. Distinguished.

(2) Evaluation of transmission characteristics The haze of the antiglare film was measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.) based on JIS K7136.

  The results of the evaluation test are shown in Table 2 together with the unit pattern creation method and the mold fabrication conditions. In addition, about Example 4, the evaluation result of two anti-glare films was shown, respectively.

  The anti-glare films of Examples 1 to 3 manufactured using a pattern in which a low spatial frequency component is reduced by applying a bandpass filter by a glare evaluation test using a photomask are all the first in which dots are randomly distributed. Compared with the anti-glare films of Comparative Examples 1 and 2 produced using this pattern, it was confirmed that the upper limit of the resolution at which glare does not occur is at a higher level and shows good optical characteristics. In addition, the two anti-glare films of Example 4 and the anti-glare film of Example 5 that were produced using the fourth pattern by applying the error diffusion method as the binarization method were both implemented using the threshold method. Compared with the anti-glare films of Examples 1 to 3, glare was not observed even with a photomask having a higher resolution, and more excellent optical properties were exhibited.

<Example 6>
A surface of a 200 mm diameter aluminum roll (JIS A5056) with copper ballad plating is prepared. Copper ballad plating consists of a copper plating layer / thin silver plating layer / surface copper plating layer, and the thickness of the entire plating layer is set to be about 200 μm. The copper plating surface is mirror-polished, and a positive photosensitive resin is applied to the polished copper plating surface and dried to form a photosensitive resin film.

  Next, a pattern in which unit patterns partially shown in FIG. 74 are repeatedly arranged is exposed on a photosensitive resin film with a laser beam and developed. The laser beam exposure and development are performed using Laser Stream FX (manufactured by Sink Laboratories). The unit pattern shown in FIG. 74 is a 32.768 mm square pattern generated at a resolution of 12800 dpi, and FIG. 74 is a 1.024 mm square cut out.

The unit pattern shown in FIG. 74 creates a second pattern by applying a high-pass filter to the first pattern and then binarizing it by applying an error diffusion method. A fourth pattern created by repeatedly applying the Monte Carlo method 60 times. The first pattern used was created by randomly distributing dots having an average dot diameter of 8 μm at a density of 10,000 / mm ² . At this time, in order to assume that the dots are distributed as uniformly as possible, a triangular lattice corresponding to the set dot density is set, and the center coordinates X and Y of the dots are respectively determined from the lattice points of the set triangular lattice. The pattern was generated by shifting with respect to the lattice. Note that the coordinates after the shift are determined by a program code according to C # (a programming language developed by Microsoft Corporation, whose language specification is defined by “JIS X 3015 programming language C #” or the like). Was used. By giving 0.3 × 15 μm to the coordinate value (X or Y) of the grid point to be shifted as Average and Deviation to this function, the dot position was shifted at random. At this time, pseudorandom numbers (“RandomFunction ()” in the C # program code) are given by giving a numerical value 607 as a seed to the SIMD oriented Fast Mersenne Twister program, SFMT ver1.3.3, which is implemented by a group of Hiroshima University. Obtained.

(Program code by C # used in Example 6)
// cx, cy: Indicates the X and Y coordinates of the newly drawn dot center.

// px, py: Indicates the X and Y coordinates of the set triangular grid point.
// pD: 0.3
// CoreSize: dot diameter
cX = NormalRandom (px, pD * CoreSize);
cY = NormalRandom (py, pD * CoreSize);
// Random number normalization function
// RandomFunction (): A function that returns a random number.

// RandomFunctionValueMax (): A function that returns the maximum value taken by a random number.
// Math: .NET Framework Math class library
public double NormalRandom (double Average, double Deviation)
{
double buff = 0;
buff = Deviation * Math.Sqrt (-2 * Math.Log (((double) RandomFunction () / (do uble) RandomFunctionValueMax ()))) * Math.Sin (2 * Math.PI * ((double) Rando mFunction () / (double) RandomFunctionValueMax ())) + Average;
if (buff <0) {buff = 0;};
return buff;
}
As the high-pass filter, a high-pass filter having a spatial frequency range lower limit B ′ of 0.067 μm ⁻¹ was used. As the error diffusion matrix, the error diffusion matrix having a diffusion distance of 4 shown in FIG. 37 and the error diffusion matrix having a diffusion distance of 5 shown in FIG. 38 are combined at a ratio of 0.9: 0.1. (FIG. 37 × 0.9 + FIG. 38 × 0.1) was used. The lower limit B ′ of the spatial frequency range of the unit pattern shown in FIG. 74 was about 0.050 μm ⁻¹ .

  Thereafter, a first etching process is performed with cupric chloride solution. In this case, the etching amount is set to 7 μm. The photosensitive resin film is removed from the roll after the first etching process, and the second etching process is performed again with cupric chloride solution. In this case, the etching amount is set to 18 μm. Thereafter, chromium plating is performed to produce a mold. At this time, the chrome plating thickness is set to 4 μm.

A photocurable resin composition GRANDIC 806T (manufactured by Dainippon Ink & Chemicals, Inc.) is dissolved in ethyl acetate to obtain a 50% strength by weight solution. Further, a photopolymerization initiator, Lucillin TPO (manufactured by BASF) Chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) is added in an amount of 5 parts by weight per 100 parts by weight of the curable resin component to prepare a coating solution. This coating solution is coated on a 80 μm thick triacetylcellulose (TAC) film so that the coating thickness after drying is 10 μm, and dried for 3 minutes in a dryer set at 60 ° C. The dried film is brought into close contact with the uneven surface of the previously obtained mold by a rubber roll so that the photocurable resin composition layer is on the mold side. In this state, light from a high-pressure mercury lamp with an intensity of 20 mW / cm ² is irradiated from the TAC film side so that the amount of light converted to h-ray is 200 mJ / cm ² to cure the photocurable resin composition layer. Thereafter, the TAC film is peeled from the mold together with the cured resin, and a transparent antiglare film made of a laminate of the cured resin having irregularities on the surface and the TAC film is produced.

<Example 7>
A pattern in which unit patterns partially shown in FIG. 75 were repeatedly arranged was created in the same manner as in Example 6 except that binarization was performed using the threshold method. Next, a mold is produced in the same manner as in Example 6 except that this pattern is used, and an antiglare film is obtained.

  76 is a diagram comparing the spatial frequency distribution of the pattern shown in FIG. 74 with the spatial frequency distribution of the pattern shown in FIG. 76 that the low spatial frequency component is further reduced in the pattern of FIG. 74 to which the error diffusion method is applied.

<Example 8>
A mold is produced in the same manner as in Example 6 except that a pattern in which a part of the pattern shown in FIG. 77 is repeatedly arranged is used to obtain an antiglare film.

  The fourth pattern shown in FIG. 77 is a 32.768 mm square pattern generated at a resolution of 12800 dpi, and FIG. 77 is a 1.024 mm square cut out. The fourth pattern is different from the first pattern in that the spatial frequency range lower limit B and the spatial frequency range upper limit T are the above formulas (I) and (II) [MainPeriod = 12 (μm), BandWidth = 20 ( %). The error diffusion according to the error diffusion matrix shown in FIG. 37 having an error diffusion distance of 4 is obtained by applying a second pattern obtained by applying a bandpass filter whose transmission band peak shape is a Gaussian type. A third pattern is created by binarization by applying the method, and the Monte Carlo method is repeatedly applied 60 times. The first pattern is an 8-bit bitmap image of 32.768 mm square at a resolution of 12800 dpi, and PIXCEL [x, y] is a two-dimensional array PIXCEL [x, y] having an 8-bit depth. = R [x + y × ImageWidth] × 255. Here, x and y are pixel coordinates in the image, and ImageWidth is the pixel width of the x coordinate. As an array R [], a pseudo-random number sequence by a random number generator subtraction algorithm of Knuth that takes a value between 0.0 and 1.0 generated by a Random class NextDouble method included in ".NET Framework 2.0 class library" Using.

<Example 9>
A pattern in which unit patterns partially shown in FIG. 78 were repeatedly arranged was created in the same manner as in Example 8 except that binarization was performed using the threshold method. Next, a mold is produced in the same manner as in Example 8 except that this pattern is used, and an antiglare film is obtained.

  79 is a diagram comparing the spatial frequency distribution of the pattern shown in FIG. 77 with the spatial frequency distribution of the pattern shown in FIG. 78. 79 that the low spatial frequency component is further reduced in the pattern of FIG. 77 to which the error diffusion method is applied.

  The transparent base material subjected to the anti-glare treatment such as the anti-glare film produced by the method of the present invention has a fine uneven surface shape reflecting a pattern with a small amount of low spatial frequency components, so that glare occurs. In other words, it exhibits sufficient antiglare properties and does not generate whiteness. In addition, since the haze is low, the contrast does not decrease even when it is arranged in an image display device. Furthermore, since there are few isolated dots that are difficult to reproduce by resist work, the etching process can be suitably performed.

<Reference example: Pattern creation and evaluation by applying a high-pass filter>
Patterns 1 to 15 were created by the method shown below.

(1) Pattern 1: Spatial frequency range for the first pattern A partially shown in FIG. 80, created by randomly distributing dots having an average dot diameter of 24 μm at a density of 1111 pieces / mm ² A second pattern was created by applying a high-pass filter having a lower limit B ′ of about 0.07 μm ⁻¹ , and then binarized by the threshold method using 127 as a threshold value to obtain a pattern 1. FIG. 81 is a diagram showing a pattern 1 partially enlarged. In creating the first pattern, the same method as the first pattern used in Example 6 was adopted to achieve uniform dot distribution.

  (2) Pattern 2: The error diffusion matrix having a diffusion distance of 4 shown in FIG. 37 and the error diffusion matrix having a diffusion distance of 5 shown in FIG. A pattern 2 as a third pattern was obtained by applying an error diffusion method using an error diffusion matrix (FIG. 37 × 0.9 + FIG. 38 × 0.1) synthesized at a ratio of 0.9: 0.1. . FIG. 82 is a partially enlarged view showing the pattern 2.

  (3) Pattern 3: Pattern 3 which is the fourth pattern was obtained by repeatedly applying the Monte Carlo method to pattern 2 60 times. FIG. 83 is a partially enlarged view showing the pattern 3.

(4) Pattern 4: Except for using the first pattern B shown in FIG. 84 that is created by randomly distributing dots having an average dot diameter of 20 μm at a density of 1600 pieces / mm ² . Pattern 4 was obtained in the same manner as Pattern 1. FIG. 85 is a partially enlarged view showing the pattern 4.

  (5) Pattern 5: The error diffusion matrix having a diffusion distance of 4 shown in FIG. 37 and the error diffusion matrix having a diffusion distance of 5 shown in FIG. A third pattern, pattern 5, was obtained by applying an error diffusion method using an error diffusion matrix (FIG. 37 × 0.9 + FIG. 38 × 0.1) synthesized at a ratio of 0.9: 0.1. . FIG. 86 is a partially enlarged view showing the pattern 5.

  (6) Pattern 6: The pattern 6 which is the 4th pattern was obtained by applying the Monte Carlo method to the pattern 5 repeatedly 60 times. FIG. 87 is a partially enlarged view showing the pattern 6.

(7) Pattern 7: Except for using the first pattern C partially shown in FIG. 88, which is created by randomly distributing dots having an average dot diameter of 16 μm at a density of 2500 / mm ² . Pattern 7 was obtained in the same manner as Pattern 1. FIG. 89 is a partially enlarged view showing the pattern 7.

  (8) Pattern 8: An error diffusion matrix with a diffusion distance of 4 shown in FIG. 37 and an error diffusion matrix with a diffusion distance of 5 shown in FIG. 38 are added to the second pattern used to create the pattern 7. A third pattern, pattern 8, was obtained by applying an error diffusion method using an error diffusion matrix (FIG. 37 × 0.9 + FIG. 38 × 0.1) synthesized at a ratio of 0.9: 0.1. . FIG. 90 is a partially enlarged view showing the pattern 8.

  (9) Pattern 9: The pattern 8 as the fourth pattern was obtained by repeatedly applying the Monte Carlo method to the pattern 8 60 times. FIG. 91 is a partially enlarged view showing the pattern 9.

(10) Pattern 10: Except for using the first pattern D shown in FIG. 92 that is created by randomly distributing dots having an average dot diameter of 12 μm at a density of 4444 / mm ² . Pattern 10 was obtained in the same manner as Pattern 1. FIG. 93 is a partially enlarged view showing the pattern 10.

  (11) Pattern 11: An error diffusion matrix with a diffusion distance of 4 shown in FIG. 37 and an error diffusion matrix with a diffusion distance of 5 shown in FIG. 38 are added to the second pattern used to create the pattern 10. By applying an error diffusion method using an error diffusion matrix (FIG. 37 × 0.9 + FIG. 38 × 0.1) synthesized at a ratio of 0.9: 0.1, a pattern 11 as a third pattern was obtained. . FIG. 94 is a partially enlarged view showing the pattern 11.

  (12) Pattern 12: The fourth pattern, Pattern 12, was obtained by applying the Monte Carlo method to the pattern 11 repeatedly 60 times. FIG. 95 is a partially enlarged view of the pattern 12.

(13) Pattern 13: Except for using the first pattern E partially shown in FIG. 96, which was created by randomly distributing dots having an average dot diameter of 8 μm at a density of 10,000 / mm ² . Pattern 13 was obtained in the same manner as Pattern 1. FIG. 97 is a partially enlarged view showing the pattern 13.

  (14) Pattern 14: An error diffusion matrix with a diffusion distance of 4 shown in FIG. 37 and an error diffusion matrix with a diffusion distance of 5 shown in FIG. 38 are added to the second pattern used to create the pattern 13. A pattern 14 as a third pattern was obtained by applying an error diffusion method using an error diffusion matrix (FIG. 37 × 0.9 + FIG. 38 × 0.1) synthesized at a ratio of 0.9: 0.1. . FIG. 98 is a partially enlarged view showing the pattern 14.

  (15) Pattern 15: The pattern 14 which is the fourth pattern was obtained by applying the Monte Carlo method to the pattern 14 repeatedly 60 times. FIG. 99 is a partially enlarged view of the pattern 15.

  The spatial frequency distributions of the first patterns A to E are shown in FIG. 100, and the spatial frequency distributions of the patterns 1 to 15 are shown in FIGS. FIG. 106 summarizes the degree of reduction of the low spatial frequency component due to the difference in the pattern manufacturing method. As shown in FIG. 106, even when any of the first patterns having different average dot diameters is used, the low spatial frequency component is effectively obtained by applying the high-pass filter, further applying the error diffusion method and the Monte Carlo method. It can be seen that In particular, the effect of reducing the low spatial frequency component is remarkable in the third pattern to which the error diffusion method is applied and the fourth pattern to which the Monte Carlo method is further applied.

  When a high-pass filter is used, unlike the band-pass filter, an upper limit value is not provided in the spatial frequency region to be extracted. Therefore, there is a concern about the generation of isolated dots, but the first pattern to be used is like the above patterns 1 to 15. In the case of a pattern in which dots are randomly arranged, many isolated dots were not seen as shown in FIG.

  On the other hand, when the first pattern in which the lightness distribution as shown in FIG. 108 is randomly arranged is used, a high-pass filter is applied to the first pattern, a pattern binarized by the threshold method, and a high-pass filter are applied. In a pattern binarized by the diffusion method, it is difficult for isolated dots to be reduced to a sufficient level, and it is preferable to reduce the isolated dots by applying the Monte Carlo method.

  FIG. 109 is a partially enlarged view of the pattern obtained by applying the high-pass filter and binarization by the threshold method to the first pattern shown in FIG. FIG. 110 partially enlarges the pattern obtained by applying the high-pass filter and binarizing by the error diffusion method to the first pattern shown in FIG. FIG. FIG. 111 shows a pattern obtained by applying a high-pass filter, binarization using an error diffusion method, and applying a Monte Carlo method to the first pattern shown in FIG. FIG. FIG. 112 is a diagram showing the number of isolated dots generated in the patterns shown in FIGS. FIG. 113 is a diagram for comparing the spatial frequency distributions of the patterns shown in FIGS. As shown in FIGS. 112 and 113, even when the first pattern includes many high spatial frequency components, the low spatial frequency components are sufficiently reduced by the application of the high-pass filter and the Monte Carlo method. It can be seen that a good pattern with few isolated dots can be obtained.

  DESCRIPTION OF SYMBOLS 1 Dot, 7 Mold substrate, 8 Surface of substrate polished by polishing process, 9 Photosensitive resin film, 10 Photosensitive resin film exposed in exposure process, 11 Photosensitive resin film not exposed in exposure process , 12 Mask, 13 Location without mask, 14 Surface formed stepwise by etching, 15 Substrate surface after first etching step (first surface irregular shape), 16 Chromium plating layer, 17 Chromium plating surface , 18 Substrate surface (second surface irregular shape) after the second etching step, 60 unit cell, 61 chrome shading pattern, 62 opening, 63 photomask, 65 light box, 66 light, 67 glass plate, 69 visual inspection Observation place, 70 Anti-glare film.

Claims (32)

At least a low spatial frequency component having a spatial frequency less than a specific value is selected from the spatial frequency components included in the first pattern with respect to the first pattern in which a plurality of dots are randomly arranged or the brightness distribution is arranged. Applying a filter to be removed or reduced to create a second pattern;
Using the second pattern, processing the concavo-convex shape on the transparent substrate;
An anti-glare treatment method for a transparent substrate.   The anti-glare processing method according to claim 1, wherein the filter is a high-pass filter that removes or reduces only a low spatial frequency component having a spatial frequency less than a specific value from a spatial frequency component included in the first pattern. 3. The anti-glare filter according to claim 2, wherein the filter is a high-pass filter that removes or reduces only a low spatial frequency component having a spatial frequency of less than 0.01 μm ⁻¹ from a spatial frequency component included in the first pattern. Processing method.   The filter removes or reduces a low spatial frequency component whose spatial frequency is less than a specific value from a spatial frequency component included in the first pattern, and removes a high spatial frequency component whose spatial frequency exceeds a specific value or The anti-glare processing method according to claim 1, wherein the anti-glare processing method is a band pass filter that extracts a spatial frequency component in a specific range by reducing the frequency band. The lower limit B of the spatial frequency in the spatial frequency component of the specific range extracted by applying the bandpass filter is 0.01 μm ⁻¹ or more, and the upper limit T is 1 / (D × 2) μm ⁻¹ or less. [D (μm) is the resolution of the processing apparatus used when processing the concavo-convex shape on the transparent substrate. The antiglare treatment method according to claim 4. The upper limit value T and the lower limit value B of the spatial frequency are expressed by the following formula (1):
0.20 <2 × (T−B) / (T + B) <0.80 (1)
The anti-glare processing method of Claim 5 which satisfy | fills. Applying a dithering method to the second pattern to further create a third pattern converted into discretized information;
The antiglare treatment method according to any one of claims 1 to 6, wherein the step of processing the concavo-convex shape on the transparent substrate is performed using the third pattern.   The anti-glare processing method according to claim 7, wherein the dithering method is an error diffusion method.   The anti-glare processing method according to claim 8, wherein the third pattern is created by applying an error diffusion method for diffusing a conversion error in a range of 3 pixels or more and 6 pixels or less.   The anti-glare processing method according to claim 7, wherein the third pattern is a pattern converted into information discretized in two stages. A step of creating a fourth pattern by moving isolated black or white pixels by a Monte Carlo method with respect to the third pattern converted into information discretized in two stages,
The process of processing an uneven | corrugated shape on the said transparent base material is an anti-glare processing method of Claim 10 performed using the said 4th pattern.   The step of processing the concavo-convex shape on the transparent substrate is performed by using the second pattern, the third pattern, or the fourth pattern to produce a mold having a concavo-convex surface, The anti-glare processing method in any one of Claims 1-11 including the process of transferring a surface on the said transparent base material.   The process of processing uneven | corrugated shape on the said transparent base material is performed using the processing apparatus which processes based on the discretized information which the said 3rd pattern or the said 4th pattern has. The anti-glare processing method according to any one of the above. At least a low spatial frequency component having a spatial frequency less than a specific value is selected from the spatial frequency components included in the first pattern with respect to the first pattern in which a plurality of dots are randomly arranged or the brightness distribution is arranged. Applying a filter to be removed or reduced to create a second pattern;
Using the second pattern, processing the concavo-convex shape on the transparent substrate;
A method for producing an antiglare film.   The anti-glare film manufacturing method according to claim 14, wherein the filter is a high-pass filter that removes or reduces only a low spatial frequency component having a spatial frequency less than a specific value from a spatial frequency component included in the first pattern. Method. The anti-glare filter according to claim 15, wherein the filter is a high-pass filter that removes or reduces only a low spatial frequency component having a spatial frequency of less than 0.01 μm ⁻¹ from a spatial frequency component included in the first pattern. A method for producing a film.   The filter removes or reduces a low spatial frequency component whose spatial frequency is less than a specific value from a spatial frequency component included in the first pattern, and removes a high spatial frequency component whose spatial frequency exceeds a specific value or The method for producing an antiglare film according to claim 14, wherein the antiglare film is a bandpass filter that extracts a spatial frequency component in a specific range by reducing the bandpass filter. The lower limit B of the spatial frequency in the spatial frequency component of the specific range extracted by applying the bandpass filter is 0.01 μm ⁻¹ or more, and the upper limit T is 1 / (D × 2) μm ⁻¹ or less. [D (μm) is the resolution of the processing apparatus used when processing the concavo-convex shape on the transparent substrate. The method for producing an antiglare film according to claim 17. The upper limit value T and the lower limit value B of the spatial frequency are expressed by the following formula (1):
0.20 <2 × (T−B) / (T + B) <0.80 (1)
The manufacturing method of the anti-glare film of Claim 18 which satisfy | fills. Applying a dithering method to the second pattern to further create a third pattern converted into discretized information;
The method for producing an antiglare film according to any one of claims 14 to 19, wherein the step of processing the concavo-convex shape on the transparent substrate is performed using the third pattern.   The method of manufacturing an antiglare film according to claim 20, wherein the dithering method is an error diffusion method.   The method for producing an antiglare film according to claim 21, wherein the third pattern is created by applying an error diffusion method in which a conversion error is diffused in a range of 3 pixels or more and 6 pixels or less.   The method for producing an antiglare film according to any one of claims 20 to 22, wherein the third pattern is a pattern converted into information discretized in two stages. A step of creating a fourth pattern by moving isolated black or white pixels by a Monte Carlo method with respect to the third pattern converted into information discretized in two stages,
The method for producing an antiglare film according to claim 23, wherein the step of processing the concavo-convex shape on the transparent substrate is performed using the fourth pattern.   The step of processing the concavo-convex shape on the transparent substrate is performed by using the second pattern, the third pattern, or the fourth pattern to produce a mold having a concavo-convex surface, The manufacturing method of the anti-glare film in any one of Claims 14-24 including the process of transferring a surface on the said transparent base material.   The process of processing the concavo-convex shape on the transparent substrate is performed using a processing apparatus that performs processing based on the discretized information of the third pattern or the fourth pattern. The manufacturing method of the anti-glare film in any one of these. A method for producing a mold according to claim 12 or 25, comprising:
A first plating step of performing copper plating or nickel plating on the surface of the mold base;
A polishing step of polishing the surface plated by the first plating step;
A photosensitive resin film forming step of forming a photosensitive resin film on the polished surface;
An exposure step of exposing the second pattern, the third pattern or the fourth pattern on a photosensitive resin film;
A developing step of developing the photosensitive resin film on which the second pattern, the third pattern, or the fourth pattern is exposed;
A first etching step of performing an etching process using the developed photosensitive resin film as a mask and forming irregularities on the polished plated surface;
A photosensitive resin film peeling step for peeling the photosensitive resin film;
A second plating step of applying chromium plating to the formed uneven surface;
A method for manufacturing a mold, including:   28. The manufacturing method according to claim 27, further comprising a second etching step in which the uneven shape of the formed uneven surface is blunted by an etching process between the photosensitive resin film peeling step and the second plating step.   29. The manufacturing method according to claim 27 or 28, wherein the concavo-convex surface formed with chromium plating in the second plating step is an concavo-convex surface of a mold transferred onto the transparent substrate.   The manufacturing method according to any one of claims 27 to 29, wherein the chromium plating layer formed by chromium plating in the second plating step has a thickness of 1 to 10 µm.   The anti-glare processing method of an image display apparatus which performs an anti-glare process on the surface of the transparent base material with which an image display apparatus is provided by the anti-glare processing method in any one of Claims 1-13.   An image display apparatus provided with the anti-glare film obtained by the method in any one of Claims 14-26.