JP3825782B2 - Anti-glare film, method for producing the same, and display device including the same - Google Patents

Description

  The present invention relates to an antiglare (antiglare) film, a method for producing the same, and a display device including the antiglare film.

  In an image display device such as a liquid crystal display, a plasma display panel, a CRT display, or an organic EL display, visibility is significantly impaired when external light is reflected on the display surface. In order to prevent such reflection of external light, televisions and personal computers that place importance on image quality, video cameras and digital cameras that are used outdoors with strong external light, and mobile phones that display using reflected light. Conventionally, a telephone or the like has been provided with a film layer for preventing external light from being reflected on the surface of the image display device. This film layer consists of a film that has been subjected to antireflection treatment using interference by the optical multilayer film, and antiglare treatment that scatters incident light by blurring the incident light by forming fine irregularities on the surface. It is divided roughly into the thing which consists of the film which was given. Of these, the former non-reflective film has a problem of high 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 film can be manufactured at a relatively low cost, it is widely used in applications such as large personal computers and monitors.

  Conventionally, such an antiglare film has, for example, applied a solvent in which a filler is dispersed on a base sheet, adjusts the coating thickness, and exposes the filler to the surface of the coating film, thereby causing random unevenness on the sheet. It is manufactured by the method etc. which form in this.

  However, the antiglare film produced by such a method is difficult to obtain the intended asperities because the arrangement and shape of the asperities depend on the dispersion state and application state of the filler in the solvent. There was a problem that the anti-glare function could not be sufficiently obtained. Furthermore, when such a conventional anti-glare film is arranged on the surface of the image display device, there is a problem that the entire display surface becomes whitish due to scattered light and the display becomes cloudy, so-called white-brown color is likely to occur. there were.

  On the other hand, in a microlens array plate used for a liquid crystal display or the like, generally concave and convex lenses are regularly arranged, and Japanese Patent Application Laid-Open No. 9-21903 (Patent Document 1) discloses adjacent microlenses. A microlens array plate having a shape that is alternately and repeatedly arranged so as not to contact each other is described. However, even with an anti-glare film in which irregularities with such regular arrangement are formed on the film, light diffraction that reflects the distribution of the uniform irregularity distance occurs, and the film appears rainbow-colored. There was a problem that the visibility of a surface fell.

Japanese Patent Laid-Open No. 9-21903

  The present invention has been made in view of the above-described problems of the prior art, and has an excellent anti-glare function, and is well-prevented by the occurrence of white-browning and a decrease in visibility due to light diffraction. It aims at providing the display apparatus provided with the film, its manufacturing method, and its anti-glare film.

  As a result of intensive studies to achieve the above object, the present inventors have obtained an appropriate variation (disorder) in which the unevenness satisfies a specific condition in an antiglare film having unevenness formed on the surface. By being disposed, the regular reflectance in the regular reflection direction for incident light incident from a predetermined angle on the antiglare film, and the direction inclined from the regular reflection direction to the film side by a predetermined angle or more. The ratio of the reflectance to the incident light and the regular reflectance is in a specific range, thereby improving the anti-glare function of the anti-glare film and reducing the visibility due to the occurrence of browning or light diffraction. Has been found to be sufficiently prevented, and the present invention has been completed.

  That is, the antiglare film of the present invention is an antiglare film having irregularities formed on the surface, and is positive for incident light incident at any angle of 5 to 30 ° from the normal direction of the antiglare film. When the regular reflectance in the reflection direction is R (0) and the reflectance with respect to the incident light in the direction inclined by 30 ° or more from the regular reflection direction to the antiglare film side is R (30 or more), R (0) is 1% or less, and the value of R (30 or more) / R (0) is 0.001 or less. By satisfying such a condition, it is possible to obtain an anti-glare film that has an excellent anti-glare function and sufficiently prevents the occurrence of white browning and the deterioration of visibility due to light diffraction.

  The antiglare film of the present invention preferably has a 60 ° reflection definition of 200% or less. By satisfying such conditions, an excellent antiglare function tends to be obtained.

Furthermore, in the antiglare film of the present invention, the unit cell having a plurality of irregularities is arranged on the surface of the antiglare film so as to have translational symmetry with the irregularities in other unit cells. In the cell, when the average value of the shortest distances between the vertices of the irregularities is m ₁ and the standard deviation of the shortest distances is σ ₁ , the value of σ ₁ / m ₁ is expressed by the following formula:
0.05 ≦ σ ₁ / m ₁ ≦ 0.3
It is preferable that the above conditions are satisfied. By forming irregularities on the antiglare film so as to satisfy such conditions, the reflection characteristics as described above are obtained, and while having an excellent antiglare function, the occurrence of browning and the distance of the irregularities There is a tendency that it is possible to sufficiently prevent a decrease in visibility due to diffraction of light reflecting the distribution of.

The method for producing an antiglare film according to the present invention includes an exposure step in which unevenness is formed on the photoresist by performing a gradation treatment on the photoresist formed on the substrate and then performing a development process; After electroforming a metal on a resist, an electroforming process for producing a metal plate on which the concavo-convex shape is transferred by peeling the metal from the photoresist; and using the metal plate, the concavo-convex shape is formed on the film. seen including a transfer step of transferring the said gradation exposure in the exposure step is carried out by applying a proximity exposure through a photomask at least bilevel respect to the photoresist, the said photomask When the distance from the photoresist is L (μm) and the outer dimension of the transmission part of the photomask is D (μm), the proximity exposure is represented by the following formula:
1.3 ≦ L / D ² ≦ 2.8
It is a manufacturing method characterized by satisfying . According to such a production method, the antiglare film of the present invention having the above-described uneven arrangement and having the above-described reflection characteristics can be produced easily and reliably. In addition, another method for producing an antiglare film according to the present invention is an exposure process in which unevenness is formed on the photoresist by performing a gradation treatment on the photoresist formed on the substrate and then developing the photoresist. Electroforming a metal on the photoresist, and then peeling the metal from the photoresist to produce a metal plate on which the concavo-convex shape is transferred, and winding the metal plate on the surface of a roll. Including a roll production step for producing an embossing roll having the unevenness on the surface, and a transfer step for continuously transferring the uneven shape onto the film using the embossing roll, and the gradation in the exposure step Exposure is performed by performing proximity exposure on the photoresist through a photomask having at least two gradations, and the photomask and the photomask The distance between the photoresists L (μm), if the external dimensions of the transmitting portion of the photomask was D (μm), the proximity exposure is represented by the following formula:
1.3 ≦ L / D ² ≦ 2.8
It is a manufacturing method characterized by satisfying. According to such a production method, there is a tendency that the antiglare film of the present invention having the above-described uneven arrangement and having the above-mentioned reflection characteristics can be produced more easily and reliably.

In addition, another method for producing an antiglare film according to the present invention is an exposure process in which unevenness is formed on the photoresist by performing a gradation treatment on the photoresist formed on the substrate and then developing the photoresist. And electroforming a metal plate on the photoresist, and then peeling the metal from the photoresist to produce a metal plate having the concavo-convex shape transferred thereon, and the concavo-convex shape using the metal plate. A gradation process in which the gradation exposure in the exposure process is performed through at least a multi-gradation photomask with respect to the photoresist, and obtained through the transfer process. The exposure is performed so that the outer shape of the unevenness when the antiglare film is viewed from the front is a shape selected from a circular shape, an elliptical shape, a polygonal shape, and an indefinite shape in which these shapes are connected. Is a manufacturing method characterized by degree is performed. According to such a production method, the antiglare film of the present invention having the above-described uneven arrangement and having the above-described reflection characteristics can be produced easily and reliably. Furthermore, another method for producing an antiglare film according to the present invention is an exposure step in which unevenness is formed on the photoresist by performing gradation treatment on the photoresist formed on the substrate and then developing the photoresist. Electroforming a metal on the photoresist, and then peeling the metal from the photoresist to produce a metal plate on which the concavo-convex shape is transferred, and winding the metal plate on the surface of a roll. a roll manufacturing process to prepare an embossing roll having the unevenness on the surface wears, seen including a transfer step, a continuously transferring the concavo-convex shape on the film using the embossing roll, the floor in the exposure step Tone exposure is performed on the photoresist through a multi-tone photomask and the antiglare film obtained through the transfer step is viewed from the front. The outer shape of the unevenness of the time, circular, oval, so that a polygonal and shaped that these shapes are selected from amorphous linked, a manufacturing method wherein the exposure step is performed. According to such a production method, there is a tendency that the antiglare film of the present invention having the above-described uneven arrangement and having the above-mentioned reflection characteristics can be produced more easily and reliably.

In addition, another method for producing an antiglare film according to the present invention is an exposure process in which unevenness is formed on the photoresist by performing a gradation treatment on the photoresist formed on the substrate and then developing the photoresist. And electroforming a metal plate on the photoresist, and then peeling the metal from the photoresist to produce a metal plate having the concavo-convex shape transferred thereon, and the concavo-convex shape using the metal plate. A gradation process in the exposure process, and the gradation exposure in the exposure process via a spatial light modulation element capable of changing the light intensity of the exposure light source at least depending on the location. And when the antiglare film obtained through the transfer step is viewed from the front, the outer shape of the unevenness is circular, elliptical, polygonal, and these shapes are connected. As a shape selected from amorphous, the exposure step is a manufacturing method characterized by being performed. According to such a production method, the antiglare film of the present invention having the above-described uneven arrangement and having the above-described reflection characteristics can be produced easily and reliably. Furthermore, another method for producing an antiglare film according to the present invention is an exposure step in which unevenness is formed on the photoresist by performing gradation treatment on the photoresist formed on the substrate and then developing the photoresist. Electroforming a metal on the photoresist, and then peeling the metal from the photoresist to produce a metal plate on which the concavo-convex shape is transferred, and winding the metal plate on the surface of a roll. Including a roll production step for producing an embossing roll having the unevenness on the surface, and a transfer step for continuously transferring the uneven shape onto the film using the embossing roll, and the gradation in the exposure step Exposure is performed via a spatial light modulation element capable of changing the light intensity of the exposure light source at least depending on the location with respect to the photoresist, and The exposure step so that the outer shape of the unevenness when the anti-glare film obtained through the copying process is viewed from the front is a shape selected from a circular shape, an oval shape, a polygon shape, and an indefinite shape in which these shapes are connected. Is performed. According to such a production method, there is a tendency that the antiglare film of the present invention having the above-described uneven arrangement and having the above-mentioned reflection characteristics can be produced more easily and reliably.

Further, in the transfer step, the unit cells having a plurality of irregularities are arranged so as to have translational symmetry with the irregularities in the other unit cells, and in the unit cells, between the peaks of the irregularities. When the average value of the shortest distance is m ₁ and the standard deviation of the shortest distance is σ ₁ , the value of σ ₁ / m ₁ is represented by the following formula:
0.05 ≦ σ ₁ / m ₁ ≦ 0.3
It is preferable to form irregularities on the surface of the film so as to satisfy the above condition. Thereby, there exists a tendency which can manufacture the anti-glare film of this invention which has the reflective characteristic mentioned above easily and reliably.

  The display device of the present invention is a display device provided with the antiglare film as described above. Such a display device can obtain high visibility due to the excellent antiglare function of the antiglare film of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, it has the anti-glare function, the anti-glare film by which generation | occurrence | production of white-brown and the visibility fall by the diffraction of light were fully prevented, its manufacturing method, and the anti-glare film are provided. Display device can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

  FIG. 1 is a schematic view showing an incident direction and a reflection direction of light with respect to the antiglare film of the present invention. The antiglare film of the present invention has a regular reflectance of the reflected light 5 in the regular reflection direction with respect to the incident light 4 incident at an angle θ of 5 to 30 ° with respect to the normal 2 of the antiglare film 1 as R. In the case of (0), R (0) needs to be 1% or less, and more preferably 0.7% or less. When the regular reflectance R (0) of the antiglare film exceeds 1%, a sufficient antiglare function cannot be obtained and visibility is deteriorated.

  FIG. 2 shows the relationship between the angle of inclination of the reflected light 5 with respect to the incident light 4 incident at an angle θ with respect to the normal 2 of the antiglare film 1 and the log reflectance from the normal of the antiglare film in the reflection direction. It is a graph. As shown in this graph, the regular reflectance R (0) is generally a reflectance peak for the incident light 4 incident at an angle θ, and the reflectance tends to decrease as the angle deviates from the regular reflection direction. In the antiglare film of the present invention, the reflectance with respect to the incident light 4 in the direction inclined by 30 ° or more from the regular reflection direction to the film side within the plane 3 including the normal 2 and the incident light 4 is R (30 or more). In this case, the value of R (30 or more) / R (0) needs to be 0.001 or less, more preferably 0.0005 or less, and still more preferably 0.0001 or less. When the value of R (30 or more) / R (0) exceeds 0.001, whitening or light diffraction occurs in the antiglare film, and the visibility decreases. For example, even when black is displayed on the display surface in a state where an antiglare film is installed on the forefront of the display device, white-browning that causes the display surface to become entirely white due to picking up light from the surroundings may occur. Note that R (30) in FIGS. 1 and 2 is relative to the incident light 4 of the reflected light 6 in a direction inclined 30 ° from the regular reflection direction to the film side within the plane 3 including the normal 2 and the incident light 4. The reflectivity is shown.

  In measuring the reflectance of the antiglare film of the present invention, it is necessary to accurately measure a reflectance of 0.001% or less, and thus a detector having a wide dynamic range is necessary. As such a detector, for example, a commercially available optical power meter can be used, and an aperture is provided in front of the detector of the optical power meter so that the angle at which the antiglare film is expected is 2 °. Measurement can be performed using the goniophotometer. Further, visible light of 380 to 780 nm can be used as incident light, and a halogen lamp or the like can be used as a light source. In addition, in the case of an antiglare film having a smooth and transparent back surface, the effect of reflection from the back surface of the antiglare film may adversely affect the measurement. For example, an antiglare film is adhered to a black acrylic plate with an adhesive or glycerin. It is preferable to measure only the reflectance of the outermost surface of the antiglare film by optically adhering using a liquid such as.

  Further, the antiglare film of the present invention needs to have irregularities formed on the surface. The unevenness is composed of a convex part and / or a concave part, and the ratio of the area between the uneven part and the flat part on the surface of the antiglare film, the shape of the unevenness, etc. satisfy the above-described reflectance conditions of the antiglare film. Although it will not restrict | limit especially if it is a thing, The one where the ratio of the area of the flat part in the anti-glare film surface is small is preferable. The ratio of the area of the flat part to the total area of the antiglare film as viewed from the front is preferably 30% or less, and more preferably 20%. When the proportion of the area of the flat portion exceeds 30%, the specular reflection component becomes strong and the antiglare function tends to decrease. In addition, the external shape of the unevenness when the antiglare film is viewed from the front is defined by the intersection of the surface parallel to the surface of the antiglare film and the unevenness as an average value of the height of the unevenness. For example, a circular shape, an elliptical shape, a polygonal shape (rectangular shape, a triangular shape, a hexagonal shape, etc.) and an indeterminate shape in which these shapes are connected may be mentioned. The shape is preferred. The average value of the external dimensions of the irregularities is preferably 1 to 50 μm, and more preferably 5 to 20 μm. Further, the ratio of the average value of the uneven step to the average value of the uneven size (step / external size) is preferably 0.01 to 0.2, and preferably 0.05 to 0.1. More preferred. The outer dimension means the diameter when the outer shape is circular, and when the outer shape is an ellipse or polygon, it means twice the average distance from the center of gravity to the outer periphery. . Moreover, in the anti-glare film of this invention, the shape of the said unevenness | corrugation does not need to be all uniform, You may have the unevenness | corrugation from which the external shape, a dimension, etc. differ.

  In addition, the antiglare film of the present invention preferably has a 60 ° reflection definition of 200% or less, and more preferably 180% or less. When the 60 ° reflection sharpness exceeds 200%, sufficient anti-glare function cannot be obtained and visibility tends to decrease.

  In addition, the 60 degree reflection sharpness of the anti-glare film in the present invention can be determined in accordance with the image sharpness measurement method by the reflection method described in JIS K 7105. However, the sum of the image sharpnesses measured by using the four types of optical combs with an optical comb width of 2 mm, 1 mm, 0.5 mm, and 0.125 mm, respectively, with the incident angle of the incident light determined by the measurement method set to 60 °. (Maximum 400%) was defined as the 60 ° reflection sharpness of the antiglare film of the present invention.

  Next, arrangement | positioning of the unevenness | corrugation in the anti-glare film of this invention is demonstrated.

In the antiglare film of the present invention, the unit cell having a plurality of irregularities is disposed on the surface thereof so as to have translational symmetry with the irregularities in the other unit cells. When the average value of the shortest distances between the vertices of the unevenness is m ₁ and the standard deviation of the shortest distance is σ ₁ , the value of σ ₁ / m ₁ is expressed by the following formula:
0.05 ≦ σ ₁ / m ₁ ≦ 0.3
It is preferable that the above conditions are satisfied.

  Here, the unit cell having a plurality of irregularities is a specific region including a plurality of irregularities on the surface of the antiglare film, and in the antiglare film of the present invention, such a unit cell is another unit. It arrange | positions so that it may have translational symmetry mutually with the unevenness | corrugation in a cell. Further, in the antiglare film of the present invention, as examples of the state in which the unit cells are arranged so as to have translational symmetry, the center-of-gravity coordinates of each unit cell are a square lattice, a rectangular lattice, an oblique lattice And a state of being arranged in a lattice shape such as a hexagonal lattice shape. By arranging the unit cells so as to have translational symmetry in this way, the reflection characteristics as described above are obtained, and while having an excellent anti-glare function, it is visually recognized by occurrence of browning or light diffraction. There exists a tendency for the anti-glare film in which the fall of property was fully prevented to be obtained, and the manufacture of an anti-glare film also tends to become easy. In the antiglare film of the present invention, the unit cell may be arranged with higher order symmetry than translational symmetry.

Moreover, the value of σ ₁ / m _{1 in} the unit cell can be obtained as follows. That is, first, the coordinates of the vertices of the convex portions or concave portions on the surface of the antiglare film are respectively obtained, and the shortest vertex coordinate distance among adjacent convex portions or the vertex coordinate distances between adjacent concave portions is set to the vertex of the above-mentioned unevenness. It is defined as the shortest distance between. Next, the shortest distance defined in this way is obtained for all convex portions or concave portions existing in the unit cell, and an average value m ₁ and a standard deviation σ ₁ are calculated, and the σ ₁ / The value of m ₁ can be determined.

In the antiglare film of the present invention, the value of σ ₁ / m ₁ obtained in the unit cell is represented by the following formula:
0.05 ≦ σ ₁ / m ₁ ≦ 0.3
It is preferable that the above conditions are satisfied. The lower limit of σ ₁ / m ₁ is preferably 0.05, more preferably 0.07, while the upper limit is preferably 0.3. More preferably, it is 25. When the value of σ ₁ / m ₁ is less than 0.05, it is difficult to obtain the reflection characteristics as described above, and in particular, light diffraction that reflects the distribution of distances between the concavo-convex vertices occurs, resulting in anti-glare. Since the film looks rainbow-colored, the visibility tends to decrease. In addition, when the value of σ ₁ / m ₁ exceeds 0.3, it is difficult to obtain the reflection characteristics as described above, and in particular, the anti-glare function cannot be sufficiently obtained, or the anti-glare film has a white brown color. There exists a tendency for visibility to fall.

In addition, the average value m ₁ of the shortest distance between the concavo-convex vertices in the unit cell is preferably 200 μm or less, and more preferably 100 μm or less. When m ₁ exceeds 200 μm, the interval between the irregularities becomes too wide, and the flat part area increases, so that the regular reflection component increases, it is difficult to obtain the reflection characteristics as described above, and a sufficient anti-glare function is obtained. There is no tendency.

  Since the distribution of the shortest distance between the concavo-convex vertices as described above is a statistical quantity, it is preferable that the population has a certain size. In the antiglare film of the present invention, the number of irregularities in the unit cell is preferably 20 or more, and more preferably 50 or more. When the number of irregularities is less than 20, the period of the unit cell is shortened, light diffraction reflecting the period of the unit cell occurs, and the antiglare film looks rainbow-colored. There exists a tendency for visibility to fall.

  The unit cell in the antiglare film of the present invention is preferably arranged with translational symmetry on the surface of the antiglare film as described above, but the period of translational symmetry of the unit cell is the light used. It is preferable that the period be equal to or greater than the coherence distance. In addition to this, in order to avoid moire caused by the display device, it is more preferable that the cycle be larger than the pixel pitch of the display device and not an integer multiple of the pixel pitch. On the other hand, if the period is too large, the burden on the production and design of irregularities increases, and therefore, a specific preferable period is a range that satisfies the above preferable conditions and is 50 to 10,000 μm, More preferably, it is 100-5,000 micrometers. By having a period that satisfies such a condition, there is a tendency that a decrease in visibility of the display surface due to light diffraction, generation of moire, or the like can be sufficiently prevented.

  In the antiglare film of the present invention, the unit cell is arranged with translational symmetry, and the period is confirmed by, for example, a method of observing the surface of the antiglare film with an optical microscope or the like, It can be confirmed by a method in which light from a light source such as a coherent laser is expanded to a beam spot having a period of translational symmetry or more and irradiated to an antiglare film, and a diffraction pattern due to the arrangement of unevenness is observed.

Moreover, it is preferable that the anti-glare film of this invention is arrange | positioned with an appropriate variation also about the unevenness | corrugation in the boundary part between unit cells as mentioned above. That is, for the unevenness in two adjacent unit cells, the average value m ₂ of the shortest distance between the vertices of the unevenness and the standard deviation σ ₂ of the shortest distance are obtained, and the value of σ ₂ / m ₂ is calculated. The value of σ ₂ / m ₂ is
0.05 ≦ σ ₂ / m ₂ ≦ 0.3
It is preferable that the above conditions are satisfied. In this way, by determining the value of σ ₂ / m ₂ in two adjacent unit cells, it is possible to confirm whether or not the arrangement of the unevenness at the boundary between the unit cells is arranged with appropriate variation. it can. The lower limit of σ ₂ / m ₂ is preferably 0.05, more preferably 0.07, while the upper limit is preferably 0.3, It is more preferable that When the value of σ ₂ / m ₂ is less than 0.05, it is difficult to obtain the reflection characteristics as described above, and in particular, light diffraction that reflects the distribution of distances between the concavo-convex vertices occurs, resulting in anti-glare. Since the film looks rainbow-colored, the visibility tends to decrease. In addition, when the value of σ ₂ / m ₂ exceeds 0.3, it is difficult to obtain the reflection characteristics as described above, and in particular, the anti-glare function cannot be obtained sufficiently, or the anti-glare film has white browning. There exists a tendency for visibility to fall.

  Next, the manufacturing method of the anti-glare film of this invention suitable as a method of obtaining the anti-glare film of this invention which was demonstrated above is demonstrated.

  The method for producing an antiglare film according to the present invention includes an exposure step in which unevenness is formed on the photoresist by performing a gradation treatment on the photoresist formed on the substrate and then performing a development process; An electroforming process for producing a metal plate having the unevenness by peeling the metal from the photoresist after electroforming metal on the resist, and a transfer for transferring the uneven shape onto the film using the metal plate A process comprising the steps of:

  In the exposure step according to the method for producing an antiglare film of the present invention, first, a photoresist is formed on a substrate to produce a substrate with a photoresist. Here, as the base material, a commonly used base material can be used without any particular limitation, for example, an inorganic transparent base material such as glass, quartz, and alumina, or a metal base material such as copper and stainless steel. Etc. can be used. The photoresist is not particularly limited as long as it is a photosensitive material. For example, a novolak resin, an acrylic resin, a copolymer of styrene and acrylic acid, a polymer of hydroxystyrene, polyvinylphenol, poly α A conventionally known positive resist composition obtained by dissolving an alkali-soluble resin such as methyl vinyl phenol and a quinonediazide group-containing compound in an organic solvent, or a photosensitizer containing an alkali-soluble resin, a photoacid generator, a crosslinking agent, and a dye. A conventionally known negative resist composition obtained by dissolving a functional resin in an organic solvent can be used.

  The film thickness of the photoresist formed on the substrate may be adjusted as appropriate depending on the thickness and shape of the unevenness to be formed on the surface of the antiglare film of the present invention. It is preferable to form the film a little thicker. A specific range of the film thickness is preferably not less than the target uneven thickness and not more than the target uneven thickness + 5 μm.

  Further, the method for forming a photoresist on the substrate is not particularly limited, and for example, it can be formed by a spin coating method, a dip coating method, a roll coating method, or the like. In addition, after film formation, in order to remove the solvent contained in the photoresist, prebaking is preferably performed at 60 to 120 ° C. for about 0.5 to 10 minutes using a hot plate, an oven, or the like. The temperature and time of the pre-bake can be appropriately adjusted depending on the type of photoresist, the sensitivity required for the photoresist, and the like.

  Next, gradation exposure is performed on the photoresist formed on the substrate thus prepared. The gradation exposure method can be performed by a conventionally known gradation exposure method. However, a method in which proximity exposure is performed on a photoresist through a photomask having at least two gradations, and at least multi-gradation photometry is performed. The method may be any one of a method of performing gradation exposure through a mask or a method of performing gradation exposure through a spatial light modulation element capable of changing the light intensity of the exposure light source at least depending on the location. preferable. Hereinafter, gradation exposure performed by these methods will be described.

  First, a method for performing proximity exposure on a photoresist through a photomask having at least two gradations will be described. The two-tone photomask used here is a portion that transmits light from the exposure light source on a substrate such as glass that is transparent to the exposure light source and has a transmittance of 100% or near that. This is a photomask in which light from an exposure light source is shielded, and a light shielding portion having a transmittance of 0% or close thereto is formed. Specifically, for example, a metal mask in which a metal such as Cr is formed as a light-shielding portion on a substrate transparent to an exposure light source, or an emulsion mask in which a light-shielding portion is formed by exposing an emulsion or the like. Can be mentioned.

  By using such a two-tone photomask and disposing it at a distance from the photoresist surface and performing proximity exposure, light diffraction occurs at the edge portion of the mask pattern of the photomask, and the photomask The image is blurred, and a continuous light amount distribution occurs from the transmission part of the photomask to the light shielding part. Since the photoresist is exposed according to the distribution of the amount of light that has been exposed to proximity, the photoresist remaining film changes according to the amount of irradiation light when the photoresist is developed, and the mask pattern and exposure amount on the developed photoresist surface. Concavities and convexities corresponding to are formed. Further, in such an exposure process, even if an optical system such as a lens system or a mechanical part such as a mask alignment system is interposed between the exposure light source and the photoresist as long as the above effects are not impaired. Good.

Furthermore, when proximity exposure is performed using the two-tone photomask, the distance between the photomask and the photoresist is L (μm), and the outer dimension of the transmissive portion of the photomask is D (μm). Proximity exposure is represented by the following formula:
1.3 ≦ L / D ² ≦ 2.8
It is preferable to satisfy the above. The reason for this can be explained as follows. That is, the behavior of light passing through a fine aperture is explained by Fresnel diffraction and Fraunhofer diffraction, and the spread of the image of light passing through the aperture is the distance (L) between the aperture and the screen, the size of the aperture (D) and the light. Changes in accordance with an index (L / D ² · λ) consisting of the wavelength λ. When the distance between the opening and the screen is short, the shape of the opening is transferred onto the screen. However, as the distance between the opening and the screen increases, the light becomes diffused about the optical axis. Therefore, when the value of L / D ² is less than 1.3, the exposure image formed on the photoresist reflects the opening pattern on the photomask, and the energy distribution is steep corresponding to the opening shape. Therefore, through holes are easily formed in the photoresist, and the light scattering function of the resulting antiglare film tends to be reduced. On the other hand, when the value of L / D ² exceeds 2.8, the light diffracted by the photomask diffuses, and it tends to be difficult to form a pattern on the photoresist surface. That is, when the value of L / D ^{2 is in} the range of 1.3 or more and 2.8 or less, an exposure image suitable for the antiglare film of the present invention tends to be formed.

  Next, a method for performing gradation exposure on a photoresist through at least a multi-tone photomask will be described. The multi-tone photomask used here is a photomask whose transmittance is changed in multiple steps or continuously depending on the location, unlike the above-described two-tone photomask. As such a multi-tone photomask, for example, a high-resolution photomask drawing apparatus such as an electron beam drawing apparatus is used to provide a light shielding part and a transmission part having a size sufficiently smaller than the wavelength of the exposure light. A mask blank is a method in which gradation is expressed by the area ratio between the area and the transmission area to make a gradation mask, and a mask blank is formed by dispersing a substance whose transmittance is changed by exposure to a high energy beam such as an electron beam or a laser in a transparent medium. In addition, a method of using a gradation mask with a transmittance continuously changed by irradiating a high energy beam with a change in intensity, and a method of irradiating light having sensitivity like an emulsion. By forming a substance that changes the optical density according to the amount on a transparent substrate, exposing the emulsion by changing the amount of light, and using a gradation mask that changes the optical density depending on the location Also obtained It can be used.

  By performing gradation exposure using such a multi-tone photomask, light corresponding to the tone of the photomask sensitizes the photoresist, so that it corresponds to the amount of light irradiated after developing the photoresist. Irregularities will be formed on the photoresist. Further, in such an exposure process, even if an optical system such as a lens system or a mechanical part such as a mask alignment system is interposed between the exposure light source and the photoresist as long as the above effects are not impaired. Good.

  Next, a method for performing gradation exposure via a spatial light modulation element capable of changing the light intensity of the exposure light source at least depending on the location on the photoresist will be described. The spatial light modulation element capable of changing the light intensity of the exposure light source depending on the location used here can spatially change the intensity of light transmitted through the element or reflected by the element. Examples of the element include a light modulation element including a large number of pixels such as a liquid crystal element and a digital micromirror element (DMD). When the liquid crystal element is used as a spatial light modulation element, it is possible to set the transmittance for each pixel of the liquid crystal element composed of a plurality of pixels, so that a spatially uniform intensity distribution from the exposure light source By transmitting the light having the light through the liquid crystal element, the intensity distribution of the exposure light according to the transmittance of the pixel of the liquid crystal element can be obtained, and the spatial intensity distribution of the exposure light irradiated to the photoresist is generated. It will be. That is, when the photoresist is developed, the photoresist film thickness changes according to the intensity of the exposed exposure light, so that it is possible to form irregularities on the surface of the photoresist. In addition, when the DMD is used as a spatial light modulation element, there are a case where light is reflected in the direction of the photoresist depending on an inclination angle of the micromirror, and a case where light is reflected in a direction other than the photoresist. By changing the light reflection time for each pixel, the substantial reflectance per unit time can be changed for each pixel. That is, by reflecting light having a spatially uniform intensity distribution from the exposure light source with the DMD, it is possible to obtain an intensity distribution of the exposure light corresponding to the time during which the micromirror is tilted. A spatial intensity distribution of the irradiated exposure light is generated. That is, when the photoresist is developed, the photoresist film thickness changes in accordance with the intensity of the exposed exposure light, so that it is possible to form irregularities on the surface of the photoresist. The spatial light modulator capable of changing the light intensity of the exposure light source depending on the location used in the exposure process of the present invention is not limited to the liquid crystal element and DMD as described above, and other spatial light modulators can be used for exposure. Using a spatial light modulator capable of creating a spatial intensity distribution of light from a light source, the intensity distribution of the exposure light to the photoresist can be created based on the principle described above, and the photoresist is developed. Since the film thickness distribution can be changed, it is possible to form surface irregularities of the photoresist.

  In the method for producing an antiglare film of the present invention, the proximity exposure method using a two-tone photomask as described above, the tone exposure method using a multi-tone photomask, and the tone exposure method using a spatial light modulator. An anti-glare film having the desired irregularities is produced by using the original plate with irregularities formed on the photoresist by the process described above, and finally transferring the irregular shape onto the film. Therefore, it is necessary to design a mask pattern in order to make a photomask for producing an original plate, but this mask pattern can provide an arrangement of unevenness necessary for the antiglare film of the present invention as described above. Need to design. Designing such a mask pattern over the entire surface of the photomask is a very labor-intensive operation, and the amount of data for the mask pattern increases, which increases the burden on the mask drawing machine. However, it is unrealistic although it is possible in principle. Even in the method of performing gradation exposure using a spatial light modulator when producing an original, it is necessary to provide data so that light modulated by the spatial light modulator has a desired spatial distribution. Great effort to generate.

  In the method for producing an antiglare film of the present invention, in order to avoid such a problem, a mask pattern corresponding to a unit cell having a plurality of projections and depressions on the antiglare film of the present invention as described above is designed and this mask is used. Arrange the patterns so that they have translational symmetry. Here, as an example of the state in which the mask pattern is arranged so as to have translational symmetry, the barycentric coordinates of each mask pattern are lattice shapes such as a square lattice shape, a rectangular lattice shape, an oblique lattice shape, and a hexagonal lattice shape. Can be listed. This can reduce the labor of designing the mask pattern for the entire photomask, which is industrially advantageous.

The exposure light source used in the exposure process according to the present invention is not particularly limited as long as it is a light source capable of exposing a photoresist. For example, g-line and h-line from a light source such as a high-pressure mercury lamp or an ultrahigh-pressure mercury lamp. The exposure process can be carried out using ultraviolet light or visible light having a wavelength such as i-line, and a laser having an oscillation wavelength near the mercury emission line as a light source. Further, the amount of light to be exposed varies depending on the shape of the target unevenness, the type of photoresist, and the like, but cannot be generally stated, but is preferably about 50 to 2000 mJ / cm ² . The exposure time can be appropriately adjusted according to the exposure light source and the required light quantity.

  In the exposure process according to the present invention, as described above, the photoresist is subjected to gradation exposure and then subjected to a development process to form irregularities on the photoresist. This development process is performed by, for example, immersing the exposed photoresist formed on the substrate in a developer corresponding to the type, and exposing the exposed portion in the case of a positive type resist, and unexposed portion in the case of a negative type resist. Is a process of forming irregularities on the photoresist by removing. As the developer, a conventionally known developer can be appropriately selected according to the photoresist to be used. Moreover, it is also preferable to rinse the photoresist with pure water after development, and it is also preferable to perform post-baking by heating for about 0.5 to 30 minutes in an oven or hot plate heated to 100 to 200 ° C. Thus, the solvent and moisture in the photoresist can be removed, and the adhesion to the substrate can be improved. The post-baking temperature and time can be appropriately adjusted depending on the type of photoresist and the like.

  In the method for producing an antiglare film of the present invention, after performing the exposure step as described above, a metal plate having unevenness is produced by electroforming a metal on a photoresist and peeling the metal from the photoresist. Perform the casting process.

  As the metal used in the electroforming, metals conventionally used in electroforming can be used without any particular limitation. For example, nickel, nickel-phosphorus alloy, iron-nickel alloy, chromium, chromium alloy, etc. Can be used. The thickness of the metal formed on the photoresist by electroforming is not particularly limited, but is preferably about 0.05 to 3 mm in terms of durability.

  In addition, when electroforming directly on the photoresist, it is necessary to make the photoresist conductive before electroforming, and a conventionally known conductive treatment, for example, a metal film having a thickness of 1 μm or less is deposited or sputtered. The conductive layer can be made conductive by a method such as a method using electroless plating or a method using electroless plating.

  When it is not desired to perform electroforming directly on the photoresist, for example, after the shape of the photoresist is transferred to a resin, the conductive treatment and electroforming as described above may be performed on the resin. Thus, after electroforming a metal to a photoresist, the metal plate which has an unevenness | corrugation can be obtained by peeling this metal from a photoresist.

  In the method for producing an antiglare film of the present invention, after performing the electroforming process as described above, a transfer process for transferring the uneven shape onto the film is performed using the obtained metal plate.

  The film used in the transfer step may be made of a single material or may be a laminate of a plurality of members, but is preferably a laminate of a plurality of members. Hereinafter, a film formed by laminating a plurality of members will be described.

  The film formed by laminating a plurality of members includes, for example, a film in which a thin resin layer is formed on a base sheet made of a thermoplastic resin or an inorganic material, and the transfer process is performed by transferring irregularities to the resin layer. It can be carried out. The sheet used as the base material is polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polyarylate, cellulose acetate, cellulose acetate, cellulose acetate, ethylene vinyl alcohol copolymer, norbornene-ethylene copolymer (Mitsui Petrochemical Manufactured by Co., Ltd., trade name: APEL, etc.), norbornene resin (manufactured by Nippon Synthetic Rubber Co., Ltd., trade name: ARTON, etc.), amorphous polyolefin (made by Nippon Zeon Co., Ltd., trade name: ZEONEX, etc.), optical A thermoplastic resin such as a polyester resin (manufactured by Kanebo Co., Ltd., trade name: O-PET), an acrylic-butadiene-styrene copolymer (manufactured by Toray Industries, Inc., trade name: Toyolac transparent grade, etc.), etc. is molded into a sheet shape. Molded into a sheet of inorganic material such as glass or metal Things, and the like.

  On the other hand, examples of the thin resin layer formed on the base sheet include a layer made of a thermoplastic resin or a radiation curable resin composition. As the thermoplastic resin, a thermoplastic resin exemplified as a material used for the substrate can also be used as a resin layer. Examples of the radiation curable resin composition include various radiation curable resin compositions for coating such as hard coat, and radiation curable resin compositions such as UV ink and EB ink. The raw material of such a radiation curable resin composition can be adjusted by mixing various monofunctional or polyfunctional (meth) acrylates, and if necessary, a photopolymerization initiator, a sensitizer, an oxidation agent. Additives such as inhibitors can be blended. Moreover, it can replace with the said (meth) acrylate composition and can also use the composition which consists of an epoxy, an oxetane compound, and a photocationic polymerization initiator.

  Examples of the monofunctional (meth) acrylate include isobornyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, butoxyethyl acrylate, lauryl acrylate, stearyl acrylate, benzyl acrylate, hexyl diglycol acrylate, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenoxyethyl acrylate, dicyclopentadiene acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, nonylphenoxyethyl cellosolve acrylate, and the like, and as polyfunctional (meth) acrylate, For example, polyethylene glycol diacrylate, ne Polyfunctional (meth) acrylates such as pentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and polyfunctional (meth) acrylate oligomers such as oligourethane (meth) acrylate and oligoester (meth) acrylate Can be mentioned. These monofunctional and polyfunctional (meth) acrylates can be used alone or in combination of two or more.

  Moreover, as a photoinitiator mix | blended as needed, benzophenone, acetophenone, benzoin, benzoin isobutyl ether, benzoin isopropyl ether, benzoin ethyl ether, 4,4'-bis (dimethylamino) benzophenone, benzyldimethyl, for example Ketal, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,2′-diisopropylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane- 1-one, 2,4,6-trimethylbenzoylphenyl diphosphine oxide and the like can be mentioned, and these can be used alone or in combination of two or more.

  Moreover, the said radiation-curable resin composition can also be diluted with various solvents as needed for the purpose of viscosity adjustment and coating property improvement. As such a diluting solvent, various general organic solvents can be used. For example, alcohol compounds such as methanol, ethanol, 1-propanol and 2-propanol, ketone compounds such as acetone and methyl ethyl ketone, ethyl acetate, Examples thereof include ester compounds such as propyl acetate and butyl acetate, and aromatic compounds such as toluene and xylene, and these can be used alone or in combination of two or more.

  In the transfer step according to the production method of the antiglare film of the present invention, a general transfer method can be used as a method for transferring the irregularities formed on the metal plate onto the film as described above. As described above, the radiation curable resin composition or the like is poured into the unevenness of the metal plate, and the resin composition is cured by irradiating ultraviolet rays or electron beams to transfer the uneven shape to the surface of the resin composition. By transferring a thermoplastic resin to a temperature equal to or higher than the Tg or softening point of the resin and then pressing the thermoplastic resin on the surface of the metal plate, the transfer process can be performed by a method of transferring the uneven shape onto the surface of the resin. When the size of the unevenness on the surface of the metal plate and the average distance between the unevenness are small, it is preferable to use a radiation curable resin composition having a lower viscosity than the thermoplastic resin. The transfer process can be performed by such a conventionally known method. However, in the method for producing an antiglare film of the present invention, before the transfer process is performed, a metal plate with unevenness is wound around the surface of the roll. It is preferable to perform a roll preparation step for producing an embossing roll having irregularities on the surface, and it is preferable to perform the transfer step by continuously transferring the irregular shape onto the film using this embossing roll. By using such a method, the concavo-convex shape can be continuously and efficiently transferred to a film having a large area, and high productivity can be obtained.

  The method for producing an antiglare film of the present invention includes an exposure process as described above, an electroforming process, and a transfer process. The antiglare film of the invention can be produced easily and reliably.

  The antiglare film obtained by the present invention can be used by being installed on the surface of a display device such as a liquid crystal display, a plasma display panel, a CRT display, or an organic EL display. For example, the anti-glare film of the present invention may be directly bonded to the surface of the display device. In the case of a liquid crystal display or the like, first, the anti-glare film is bonded to the polarizing plate, and this is displayed on the display device surface. You may make it stick to. Such a display device provided with the antiglare film of the present invention can scatter incident light by the unevenness of the surface of the antiglare film to blur the reflected image, and can obtain excellent visibility.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
First, 75 circular openings having a diameter of 9 μm (= D) are arranged in a 127 μm × 127 μm square region, the average value m ₁ of the shortest distance between the center coordinates of each opening is 14.7 μm, and the standard deviation σ of the shortest distance It arrange | positioned so that ₁ might be 1.049. This was arranged as a unit cell on the entire area of 80 mm × 80 mm with a period of 127 μm, and a 6-inch square two-tone photomask was produced.

Next, a positive photoresist (manufactured by Tokyo Ohka Co., Ltd., trade name: PR13) was spin-coated on the glass substrate so as to have a thickness of about 1.1 μm. The obtained glass substrate with a photoresist was placed on a hot plate heated to 110 ° C. for 60 seconds and prebaked. The photomask is held on this photoresist so that the exposure gap is 180 μm (= L), and g, h, i multiline light of an ultrahigh pressure mercury lamp as an exposure light source is 150 mJ / cm ^{2 in} h-line conversion. Proximity exposure was performed by irradiation. At this time, the value of L / D ² was 2.22.

  The exposed glass substrate with a photoresist was immersed in a 0.5% aqueous potassium hydroxide solution at 23 ° C. for 80 seconds, developed, and rinsed with pure water. Then, the photoresist by which the unevenness | corrugation was formed in the surface was obtained by heating for 18 minutes in the oven heated at 200 degreeC.

  On the photoresist thus obtained, a nickel film was formed by a vapor deposition method, and the conductive treatment of the photoresist was performed. Next, a nickel film is formed on the photoresist by electroforming so as to have a thickness of about 0.3 mm, and the nickel film has a thickness of 0.2 mm on the back surface of the nickel film with the nickel film attached to the photoresist. Polished to become. The polished nickel film was peeled from the photoresist to obtain a metal plate having irregularities on the surface.

  As materials for the film, UF8001 (trade name, manufactured by Kyoeisha Chemical Co., Ltd., oligourethane acrylate) 50 parts by weight, IBXA (trade name, manufactured by Kyoeisha Chemical Co., Ltd., isobornyl acrylate) 50 parts by weight, Irgacure 184 (trade name) 2 parts by weight of Ciba Specialty Chemicals) were mixed to obtain an ultraviolet curable resin composition (hereinafter referred to as UV resin).

The UV resin thus obtained was poured onto the irregularities of the metal plate so as to have a thickness of about 7 μm, and the top was covered with a PET film having a thickness of 80 μm. After the UV resin is cured by irradiating light of a high-pressure mercury lamp to a light amount of 200 mJ / cm ² , the PET film is peeled from the metal plate together with the UV resin, and the UV resin and the PET film having unevenness on the surface A transparent antiglare film consisting of the laminate was obtained.

The resulting antiglare film was irradiated with light of a wavelength of 543.5 nm of a He—Ne laser, and a diffraction pattern was observed. The corresponding period was calculated from the angle from the spot of the zero-order light to the spot of the primary light, and the average value m ₁ of the shortest distance between the convex vertices on the surface of the antiglare film was found to be 14.7 μm. It coincided with the average value of the shortest distance of the opening of the photomask. In addition, the standard deviation σ ₁ was found to be 1.049, which coincided with the standard deviation of the shortest distance of the used photomask opening. The value of σ ₁ / m ₁ calculated by these was 0.07. Further, when the corresponding period was calculated from the angle of the diffraction spots that looked like a square lattice, it was 127 μm, which coincided with the period of the unit cell of the photomask used.

(Comparative Example 1)
An AG6 film (manufactured by Sumitomo Chemical Co., Ltd.) was prepared as an antiglare film. The irregularities on the surface of the AG6 film are irregularly arranged on the entire film surface, the average value m ₁ of the shortest distance between the convex vertices is 8.8 μm, the standard deviation σ ₁ is 2.87, The value of ₁ / m ₁ was 0.326.

[Measurement of reflectance]
The reflectance profiles of the antiglare films obtained in Example 1 and Comparative Example 1 were measured as follows. That is, an optical power meter (optical power meter ML9001 manufactured by Anritsu Co., Ltd.) is used as a detector, an aperture is provided in front of the detector, and measurement is performed using a variable angle photometer that makes the sample look at an angle of 2 °. Went. The reflectance is measured by using a halogen lamp (manufactured by Chuo Seiki Co., Ltd., SPH-100) as a light source, using a condensing optical system with a focal length of 300 mm, and placing 15 mm light at a distance of 300 mm at the exit of the condensing optical system. The sample was collected so as to have a diameter of 2.5 mm on the sample. For the reflectance reference, nothing was placed at the sample position, and the amount of light when detected by the optical power meter through an aperture of 5 mmφ arranged 165 mm away from the sample was 100%. Then, the antiglare film obtained in Example 1 and Comparative Example 1 was attached as a sample, the angle of incident light from the light source to the antiglare film was set to 15 °, and the detector with the aperture was antiglare film The amount of light when rotating around was measured, the angle dependency of the reflectance was measured, and a reflectance profile was obtained. The obtained reflectance profile is shown in FIG. Moreover, the reflectance profile at the time of setting the angle of the incident light from the light source to an anti-glare film to 30 degrees was obtained similarly to the said measuring method. The obtained reflectance profile is shown in FIG.

  From the obtained measurement results, the reflectance when the angle of the incident light from the light source to the antiglare film is set to 15 ° is the regular reflection in the antireflection film of Example 1 in the regular reflection direction with respect to the incident light. The rate R (0) is 0.42%, the rate of reflection R (30) in the direction inclined 30 ° from the regular reflection direction to the film side is 0.00013%, and the value of R (30) / R (0). Was 0.00031. Further, in the antiglare film of Comparative Example 1, the regular reflectance R (0) in the regular reflection direction with respect to incident light is 0.23%, and the reflectance R in the direction inclined 30 ° from the regular reflection direction to the film side ( 30) was 0.00048%, and the value of R (30) / R (0) was 0.0069. In addition, in the anti-glare film of Example 1 and Comparative Example 1, the reflectance R (30 or more) with respect to the incident light in the direction inclined by 30 ° or more from the regular reflection direction toward the film side is the reflectance as shown in FIG. R (30) or less.

  Moreover, the reflectance when the angle of incident light from the light source to the antiglare film is set to 30 ° is the regular reflectance R (0) in the regular reflection direction with respect to the incident light in the antiglare film of Example 1. Is 0.48%, and the reflectance R (30) in the direction inclined 30 ° from the regular reflection direction to the film side is 0.0001% or less and below the detection limit, and the value of R (30) / R (0) Was 0.0002 or less. Further, in the antiglare film of Comparative Example 1, the regular reflectance R (0) in the regular reflection direction with respect to incident light was 0.25%, and the reflectance R in the direction inclined 30 ° from the regular reflection direction to the film side ( 30) was 0.00212%, and the value of R (30) / R (0) was 0.0085. In addition, in the anti-glare film of Example 1 and Comparative Example 1, the reflectance R (30 or more) with respect to incident light in the direction inclined by 30 ° or more from the regular reflection direction toward the film side is the reflectance as shown in FIG. R (30) or less.

[Measurement of 60 ° reflection sharpness]
The antiglare film obtained in Example 1 and Comparative Example 1 has a 60 ° reflection sharpness, with a black vinyl tape applied to the back surface of the antiglare film, and reflection from the back surface suppressed, ICM- manufactured by Suga Test Instruments Co., Ltd. Measurement was performed using 1DP. As a result, the 60 ° reflection definition was 114.3% for the antiglare film of Example 1 and 24.0% for the antiglare film of Comparative Example 1.

[Measurement of total light transmittance and haze]
The total light transmittance and haze of the antiglare films obtained in Example 1 and Comparative Example 1 were measured using a haze computer (manufactured by Suga Test Instruments Co., Ltd., HGM-2DP). As a result, the total light transmittance of the antiglare film of Example 1 was 82.1% and the haze was 17.7%. The total light transmittance of the antiglare film of Comparative Example 1 was 88.3%, and the haze was It was 24.9%.

[Evaluation of anti-glare function]
The antiglare film obtained in Example 1 and Comparative Example 1 was bonded to a black acrylic plate with an adhesive, and illuminated with a tubular fluorescent lamp (model ENV-B, manufactured by Otsuka Electronics Co., Ltd.). The brightness of the reflected light from the antiglare film was measured using a luminance meter (Topcon, BM7, 2 ° field of view) installed in the line direction. In addition, the measurement of brightness | luminance adjusts the incident angle of light by changing the height of a tubular fluorescent lamp so that the incident angle to an anti-glare film may be 10 degrees, 15 degrees, 20 degrees, and 30 degrees, The brightness of the reflected light of the antiglare film with respect to the incident angle was measured. As a result, in the antiglare film of Example 1, the reflected light luminance for each incident angle was 61.4 cd / m ² , 15.6 cd / m ² , 7.9 cd / m ² , and 7.3 cd / m ² , respectively. there were. Further, in the antiglare film of Comparative Example 1, respectively reflected light intensity for each angle of ^{incidence, 74.2cd / m 2, 60.1cd /} m 2, 47.2cd / m 2, 33.2cd / m 2 met It was. As is clear from this result, the reflected light luminance of the antiglare film of Example 1 is lower than the reflected light luminance of the antiglare film of Comparative Example 1 with respect to light incident from any angle. It was confirmed that the glare function was excellent. In the antiglare film of Example 1, the reflected light luminance decreases sharply as the incident angle of light increases, and the difference from the reflected light luminance of the antiglare film of Comparative Example 1 increases. From this, it was confirmed that the antiglare film of Example 1 has reduced the occurrence of white brown due to scattered light as compared with the antiglare film of Comparative Example 1. The occurrence of this white brown was further confirmed by the following visual evaluation.

[Evaluation of light diffraction, diffraction of light]
The anti-glare film obtained in Example 1 and Comparative Example 1 was bonded onto a black acrylic plate with an adhesive, and the room was bright (two 40W straight tube fluorescent lamps were grouped and arranged every 3 m. In an office environment where the incident angle of light from a pair of fluorescent lamps is 30 °, and the tester visually observed from the normal direction of the antiglare film, the antiglare of Example 1 The film only looked slightly whiter than the surrounding black acrylic plate, but the antiglare film of Comparative Example 1 appeared whiter and cloudy than the surrounding black acrylic plate. Also from the result of this visual evaluation, it was confirmed that the antiglare film of Example 1 had less browning and improved visibility as compared with the antiglare film of Comparative Example 1. .

  In addition, when the tester observed a decrease in visibility due to light diffraction by the same visual evaluation method, the rainbow color that was thought to be due to light diffraction was slightly seen in the antiglare film of Example 1, No reduction in visibility was observed. On the other hand, in the antiglare film of Comparative Example 1, an iridescent color believed to be due to light diffraction was seen, and a reduction in visibility was observed.

[Visibility evaluation when pasted to display]
The antiglare film obtained in Example 1 and Comparative Example 1 was bonded to a polarizing plate, and this was bonded to the surface of a liquid crystal display to produce a display device provided with the antiglare film of the present invention. The same image is displayed on these display devices, and the incident angle of light from one set of fluorescent lamps is bright in a bright room (an office environment in which two 40W type straight fluorescent lamps are arranged every 3 m). When the display device was arranged so as to be 30 ° and the tester visually confirmed the anti-glare property from the normal direction of the display device, the display device provided with the anti-glare film of Example 1 displayed a display image. Although a decrease in visibility was not recognized and sufficient anti-glare property was confirmed, in the display device provided with the anti-glare film of Comparative Example 1, reflection of external light occurred and a decrease in the visibility of the display image was recognized. It was.

  As is clear from the above results, the antiglare film of the present invention (Example 1) exhibits an antiglare function superior to the antiglare film of Comparative Example 1, and is visible by white browning or light diffraction. It was confirmed that the decrease in the temperature was sufficiently prevented.

It is the schematic diagram which showed the incident direction and reflection direction of the light with respect to the anti-glare film of this invention. It is the graph which showed the relationship between the inclination angle from the anti-glare film normal of a reflection direction with respect to the incident light which injected with the angle (theta) with respect to the normal of the anti-glare film, and log reflectivity. It is the graph which showed the result of the reflectance profile with respect to the light which injected with the angle of 15 degrees with respect to the anti-glare film obtained in Example 1 and Comparative Example 1. FIG. It is the graph which showed the result of the reflectance profile with respect to the light which injected with the angle of 30 degrees with respect to the anti-glare film obtained in Example 1 and Comparative Example 1. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Anti-glare film, 2 ... Normal of anti-glare film, 3 ... Surface containing normal and incident light, 4 ... Incident light, 5 ... Reflected light in regular reflection direction , 6 ... Reflected light in a direction inclined by 30 ° from the regular reflection direction toward the film side.

Claims (11)

An anti-glare film with irregularities formed on the surface,
R (0) is the regular reflectance in the regular reflection direction with respect to incident light incident at an angle of 5 to 30 ° from the normal direction of the antiglare film,
When the reflectance with respect to the incident light in the direction inclined by 30 ° or more from the regular reflection direction to the antiglare film side is R (30 or more),
An antiglare film, wherein R (0) is 1% or less and the value of R (30 or more) / R (0) is 0.001 or less.   The antiglare film according to claim 1, wherein the 60 ° reflection definition is 200% or less. On the surface of the antiglare film, unit cells having a plurality of irregularities are arranged so as to have translational symmetry with the irregularities in other unit cells,
In the unit cell, when the average value of the shortest distance between the vertices of the unevenness is m ₁ and the standard deviation of the shortest distance is σ ₁ , the value of σ ₁ / m ₁ is expressed by the following formula:
0.05 ≦ σ ₁ / m ₁ ≦ 0.3
The antiglare film according to claim 1, wherein the antiglare film satisfies the following conditions. An exposure step of forming irregularities on the photoresist by performing development after performing gradation exposure on the photoresist formed on the substrate;
After electroforming metal on the photoresist, an electroforming step of producing a metal plate to which the uneven shape is transferred by peeling the metal from the photoresist;
A transfer step of transferring the uneven shape onto the film using the metal plate;
Only including,
The gradation exposure in the exposure step is performed by performing proximity exposure on the photoresist through a photomask of at least two gradations,
When the distance between the photomask and the photoresist is L (μm) and the outer dimension of the transmission part of the photomask is D (μm), the proximity exposure is represented by the following formula:
1.3 ≦ L / D ² ≦ 2.8
The manufacturing method of the anti-glare film characterized by satisfy | filling . An exposure step of forming irregularities on the photoresist by performing development after performing gradation exposure on the photoresist formed on the substrate;
After electroforming metal on the photoresist, an electroforming step of producing a metal plate to which the uneven shape is transferred by peeling the metal from the photoresist;
A roll production step of winding the metal plate around the surface of the roll to produce an embossing roll having the irregularities on the surface;
A transfer step of continuously transferring the uneven shape onto the film using the embossing roll;
Only including,
The gradation exposure in the exposure step is performed by performing proximity exposure on the photoresist through a photomask of at least two gradations,
When the distance between the photomask and the photoresist is L (μm) and the outer dimension of the transmission part of the photomask is D (μm), the proximity exposure is represented by the following formula:
1.3 ≦ L / D ² ≦ 2.8
The manufacturing method of the anti-glare film characterized by satisfy | filling . An exposure step of forming irregularities on the photoresist by performing development after performing gradation exposure on the photoresist formed on the substrate;
After electroforming metal on the photoresist, an electroforming step of producing a metal plate to which the uneven shape is transferred by peeling the metal from the photoresist;
A transfer step of transferring the uneven shape onto the film using the metal plate;
Including
The gradation exposure in the exposure step is performed with respect to the photoresist through at least a multi-tone photomask; and
The exposure is performed so that the outer shape of the unevenness when the antiglare film obtained through the transfer step is viewed from the front is a shape selected from a circular shape, an elliptical shape, a polygonal shape, and an indefinite shape in which these shapes are connected. antiglare film producing method of you, characterized in that the process is performed. An exposure step of forming irregularities on the photoresist by performing development after performing gradation exposure on the photoresist formed on the substrate;
After electroforming metal on the photoresist, an electroforming step of producing a metal plate to which the uneven shape is transferred by peeling the metal from the photoresist;
A roll production step of winding the metal plate around the surface of the roll to produce an embossing roll having the irregularities on the surface;
A transfer step of continuously transferring the uneven shape onto the film using the embossing roll;
Including
The gradation exposure in the exposure step is performed with respect to the photoresist through at least a multi-tone photomask; and
The exposure is performed so that the outer shape of the unevenness when the antiglare film obtained through the transfer step is viewed from the front is a shape selected from a circular shape, an elliptical shape, a polygonal shape, and an indefinite shape in which these shapes are connected. antiglare film producing method of you, characterized in that the process is performed. An exposure step of forming irregularities on the photoresist by performing development after performing gradation exposure on the photoresist formed on the substrate;
After electroforming metal on the photoresist, an electroforming step of producing a metal plate to which the uneven shape is transferred by peeling the metal from the photoresist;
A transfer step of transferring the uneven shape onto the film using the metal plate;
Including
The gradation exposure in the exposure step is performed via a spatial light modulation element capable of changing the light intensity of an exposure light source depending on at least a place with respect to the photoresist , and
The exposure is performed so that the outer shape of the unevenness when the antiglare film obtained through the transfer step is viewed from the front is a shape selected from a circular shape, an elliptical shape, a polygonal shape, and an indefinite shape in which these shapes are connected. antiglare film producing method of you, characterized in that the process is performed. An exposure step of forming irregularities on the photoresist by performing development after performing gradation exposure on the photoresist formed on the substrate;
After electroforming metal on the photoresist, an electroforming step of producing a metal plate to which the uneven shape is transferred by peeling the metal from the photoresist;
A roll production step of winding the metal plate around the surface of the roll to produce an embossing roll having the irregularities on the surface;
A transfer step of continuously transferring the uneven shape onto the film using the embossing roll;
Including
The gradation exposure in the exposure step is performed via a spatial light modulation element capable of changing the light intensity of an exposure light source depending on at least a place with respect to the photoresist , and
The exposure is performed so that the outer shape of the unevenness when the antiglare film obtained through the transfer step is viewed from the front is a shape selected from a circular shape, an elliptical shape, a polygonal shape, and an indefinite shape in which these shapes are connected. antiglare film producing method of you, characterized in that the process is performed. In the transfer step, unit cells having a plurality of irregularities are arranged so as to have translational symmetry with the irregularities in other unit cells, and the shortest distance between the apexes of the irregularities in the unit cell. Where m _{1 is} the average value and σ ₁ is the standard deviation of the shortest distance, the value of σ ₁ / m ₁ is expressed by the following formula:
0.05 ≦ σ ₁ / m ₁ ≦ 0.3
The method for producing an antiglare film according to any one of claims 4 to 9, wherein irregularities are formed on the surface of the film so as to satisfy the above condition . The display apparatus provided with the anti-glare film as described in any one of Claims 1-3.

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