JP6349830B2 - Method for manufacturing antireflection article and method for manufacturing mold for manufacturing antireflection article - Google Patents

Description

  The present invention relates to an antireflection article for preventing reflection by closely arranging a large number of minute protrusions at intervals equal to or shorter than the shortest wavelength of an electromagnetic wave wavelength band for preventing reflection.

  In recent years, regarding an antireflection film, which is a film-shaped antireflection article, there has been proposed a method for preventing reflection by arranging a large number of microprotrusions closely on the surface of a transparent substrate (transparent film) (patent) References 1-3). This method utilizes the principle of a so-called moth-eye structure, and the refractive index for incident light is continuously changed in the thickness direction of the substrate, whereby a discontinuous interface of refractive index is obtained. Is eliminated to prevent reflection.

  In the antireflection article according to this moth-eye structure, the microprojections are closely arranged so that the distance d between adjacent microprojections is equal to or less than the shortest wavelength Λmin (d ≦ Λmin) of the wavelength band of the electromagnetic wave to prevent reflection. The Moreover, each microprotrusion is produced so that a cross-sectional area may become small gradually toward the front end side from a transparent base material so that it may be planted on a transparent base material.

  In the antireflection film according to this type of moth-eye structure, since the reflectance can be lowered, it can be applied to an image display device such as a liquid crystal display device to improve contrast and improve visibility. However, the visibility of such an image display device is required to be further improved. For this purpose, it is required to further reduce the reflection.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589

  The present invention has been made in view of such a situation, and an object of the present invention is to further reduce the reflection of an antireflection article having a moth-eye structure as compared with the conventional art.

  In order to solve the above-mentioned problems, the present inventor has made intensive research and created micro-projections related to the moth-eye structure on the surface shape of the anti-glare layer for preventing reflection by scattering the reflected light. The idea of appropriately setting the surface shape of the layer has been reached, and the present invention has been completed.

    Specifically, the present invention provides the following.

(1) In an antireflection article in which microprotrusions are closely arranged, and an interval between the adjacent microprotrusions is equal to or less than the shortest wavelength of the wavelength band of electromagnetic waves for antireflection,
Formed so that the envelope surface of the valley bottom, which is created by sequentially following the root portion of the microprotrusions, exhibits undulations,
The envelope of the valley bottom is
The average interval Sm is 100 μm or more and 600 μm or less,
The average inclination angle θa is not less than 0.1 degrees and not more than 1.2 degrees,
The 10-point average roughness Rz is more than 0.2 μm and not more than 1.0 μm.

  According to (1), it is possible to appropriately add a function of preventing reflection by the curved surface shape of the envelope surface of the valley bottom to the reflection preventing function by the moth-eye structure, thereby further reducing the reflection.

(2) In (1),
The microprotrusions are
Multimodal microprojections that are microprojections having a plurality of vertices and single-peak microprojections that have one microprojection are mixed.

  According to (2), the scratch resistance can be further improved, and further the antireflection function can be improved.

  (3) An image display device in which the antireflection article according to (1) or (2) is arranged on the panel surface of the image display panel.

  According to (3), it is possible to provide an image display device in which the reflection is further reduced and the reflection is sufficiently prevented.

(4) In a mold for manufacturing an antireflective article used for manufacturing an antireflective article,
The antireflective article is
The microprojections are closely arranged, and the interval between the adjacent microprojections is an antireflection article that is equal to or shorter than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
Formed so that the envelope surface of the valley bottom, which is created by sequentially following the root portion of the microprotrusions, exhibits undulations,
The mold for manufacturing the antireflection article is:
A minute hole corresponding to the minute protrusion is produced closely,
The surface on which the fine holes are formed is an uneven surface that exhibits undulation corresponding to the envelope surface of the valley bottom,
The average interval Sm is 100 μm or more and 600 μm or less,
The average inclination angle θa is not less than 0.1 degrees and not more than 1.2 degrees,
The 10-point average roughness Rz is more than 0.2 μm and not more than 1.0 μm.

  According to (4), with respect to the antireflection article capable of further reducing the reflection by appropriately adding the antireflection function by the moth-eye structure to the antireflection function by the curved shape of the envelope surface of the valley bottom, It can be produced efficiently by processing.

(5) In the method for producing an antireflection article, in which microprotrusions are closely arranged, and the interval between the adjacent microprotrusions is equal to or shorter than the shortest wavelength of the wavelength band of the electromagnetic wave for antireflection,
A mold making process for producing a manufacturing mold for the molding process;
A shaping treatment step of producing the antireflection article by a shaping treatment using the production mold,
The mold making process includes
On the surface of the base material, a base layer manufacturing process for preparing a base layer with a surface shape exhibiting undulation,
A micro-hole manufacturing step for manufacturing micro-holes corresponding to the micro-protrusions in the base layer by repeating anodization and etching,
The manufacturing process of the underlayer includes
On the surface of the base material, a process for producing an uneven surface layer for producing an uneven surface layer with a surface shape corresponding to the undulation,
An aluminum layer forming step of forming an aluminum layer on the surface of the uneven surface layer.

  According to (5), after producing an uneven surface layer by effectively using a method for producing an antiglare layer that scatters reflected light to prevent reflection, a microprojection is formed on the curved surface according to the surface shape of the uneven surface layer. Corresponding fine holes can be made.

(6) In the method for producing an antireflection article, in which microprotrusions are closely arranged, and the interval between adjacent microprotrusions is equal to or shorter than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A mold making process for producing a manufacturing mold for the molding process;
A shaping treatment step of producing the antireflection article by a shaping treatment using the production mold,
The mold making process includes
On the surface of the support, a process for producing an uneven surface layer for producing an uneven surface layer with a surface shape exhibiting undulation,
On the surface of the concavo-convex surface layer, a transfer layer support producing step for producing a transfer support layer,
A peeling step of peeling the transfer support layer from the uneven surface layer;
A production step of an aluminum layer for producing an aluminum layer on the surface of the transfer support layer peeled in the peeling step;
A microhole creating step of creating microholes corresponding to the microprotrusions on the surface of the aluminum layer by repetition of anodizing treatment and etching treatment,
A disposing step of disposing a laminate of the aluminum layer formed by forming the fine holes and the support layer for transfer on a base material.

  According to (6), after producing an uneven surface layer by effectively using a method for producing an antiglare layer that scatters reflected light to prevent reflection, a microprojection is formed on the curved surface according to the surface shape of the uneven surface layer. Corresponding micro holes can be manufactured, which effectively uses anti-glare layer manufacturing techniques that scatter reflected light to prevent reflections, effectively reducing anti-reflection articles that can further reduce reflections Can be produced well.

(7) In the method of manufacturing a mold for manufacturing an antireflective article, in which microprotrusions are closely arranged, and the interval between adjacent microprotrusions is equal to or less than the shortest wavelength of the wavelength band of electromagnetic waves to prevent reflection,
On the surface of the base material, a base layer manufacturing process for preparing a base layer with a surface shape exhibiting undulation,
A micro-hole manufacturing step for manufacturing micro-holes corresponding to the micro-protrusions in the base layer by repeating anodization and etching,
The manufacturing process of the underlayer includes
On the surface of the base material, a process for producing an uneven surface layer for producing an uneven surface layer with a surface shape corresponding to the undulation,
An aluminum layer forming step of forming an aluminum layer on the surface of the uneven surface layer.

  According to (7), when producing an anti-reflection article by a shaping process, after producing an uneven surface layer by effectively using a method for producing an anti-glare layer that scatters reflected light to prevent reflection, Fine holes corresponding to the fine protrusions can be formed on the curved surface formed by the surface shape of the uneven surface layer.

(8) In the method of manufacturing a mold for manufacturing an antireflection article, in which microprotrusions are arranged in close proximity, and the interval between adjacent microprotrusions is equal to or less than the shortest wavelength of the wavelength band of electromagnetic waves to prevent reflection,
On the surface of the support, a process for producing an uneven surface layer for producing an uneven surface layer with a surface shape exhibiting undulation,
On the surface of the concavo-convex surface layer, a transfer support layer producing step for producing a transfer support layer,
A peeling step of peeling the transfer support layer from the uneven surface layer;
A production step of an aluminum layer for producing an aluminum layer on the surface of the transfer support layer peeled in the peeling step;
A microhole creating step of creating microholes corresponding to the microprotrusions on the surface of the aluminum layer by repetition of anodizing treatment and etching treatment,
A disposing step of disposing a laminate of the aluminum layer formed by forming the fine holes and the support layer for transfer on a base material.

  According to (8), when an antireflection article is produced by a shaping process, the production method of the antiglare layer for preventing the reflection by scattering the reflected light from the manufacturing mold used for the shaping process is effective. It can be produced by using.

  With respect to the antireflection article having the moth-eye structure, the reflection can be further reduced as compared with the conventional case.

1 is a conceptual perspective view showing an antireflection article according to a first embodiment of the present invention. It is a figure which shows the detail of the reflection preventing article of FIG. It is a figure where it uses for description of a multimodal microprotrusion. It is a photograph of multimodal microprotrusions. It is a figure where it uses for description of an adjacent protrusion. It is a figure where it uses for description of the maximum point. It is a figure which shows a Delaunay figure. It is a frequency distribution diagram used for measurement of the distance between adjacent protrusions. It is a frequency distribution figure with which it uses for description of minute height. It is a graph which shows the comparison result of an Example and a comparative example. It is a chart which shows the examination result different from FIG. It is a figure which shows the measurement system used for the detailed examination of a reflection. It is a figure which shows the measurement result of the sample for comparative examination. It is a figure which shows the measurement result of the comparative example 1. It is a figure which shows the measurement result of the comparative example 4. It is a figure which shows the measurement result of an Example. It is the figure which summarized the measurement result of FIGS. 13-16 about the incident angle of 80 degree | times. It is the figure which put together the measurement result of FIGS. 13-16 about the incident angle of 10 degree | times. It is a figure which shows the manufacturing process of the antireflection article | item of FIG. It is a figure which shows the roll plate which concerns on the reflection preventing article of FIG. It is a figure which shows the preparation processes of the roll plate of FIG. It is a flowchart which shows the preparation processes of a base layer. It is a figure which shows the preparation process of a base layer. It is a figure where it uses for detailed description of an anodizing process and an etching process. It is a figure where it uses for description of the metal mold | die production process which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, a microprotrusion having a plurality of vertices will be referred to as a multimodal microprotrusion, and a microprotrusion having only one apex will be referred to as a unimodal microprotrusion.

[First Embodiment]
FIG. 1 is a diagram (conceptual perspective view) showing an antireflection article according to a first embodiment of the present invention. This antireflection article 1 is an antireflection film whose overall shape is formed by a film shape. In the image display device according to this embodiment, the antireflection article 1 is attached to and held on the viewer side surface (panel surface) of the image display panel, and the antireflection article 1 prevents external light such as sunlight and electric light. Visibility is improved by reducing reflection on the screen. The antireflection article is not limited to a flat film shape, but may be a flat sheet shape or a flat plate shape (referred to as a film, a sheet, or a plate in order of relatively small thickness). In addition, instead of a flat shape, a curved shape, a three-dimensional film shape, a sheet shape, or a plate shape can be used, and various lenses, prisms, and other three-dimensional shapes are appropriately used depending on the application. Can be adopted.

  Here, the antireflection article 1 is produced by closely arranging a large number of minute protrusions on the surface of the substrate 2 made of a transparent film. Here, the base material 2 is, for example, a cellulose resin such as TAC (Triacetylcellulose), an acrylic resin such as PMMA (polymethyl methacrylate), a polyester resin such as PET (Polyethylene terephthalate), or PP (polypropylene). Polyolefin resins such as PVC, vinyl resins such as PVC (polyvinyl chloride), and various transparent resin films such as PC (polycarbonate) can be applied. As described above, the shape of the antireflection article is not limited to the film shape, and various shapes can be adopted, so that the base material 2 can be used in addition to these materials, for example, according to the shape of the antireflection article. Various transparent inorganic materials such as glass such as soda glass, potash glass, lead glass, ceramics such as PLZT, quartz, and meteorite can be applied.

  In the antireflection article 1, an uncured resin layer (hereinafter, referred to as a receiving layer as appropriate) is formed on a base material 2 to be a receiving layer having a fine concavo-convex shape composed of a group of minute protrusions. The molding process is cured by curing, whereby fine protrusions are placed in close contact with the surface of the substrate 2. In this embodiment, an acrylate ultraviolet curable resin, which is one of the molding resins used for the molding process, is applied to the receiving layer 4, and the ultraviolet curable resin layer (4) is formed on the substrate 2. Is done. The antireflection article 1 is manufactured so that the refractive index gradually changes in the thickness direction due to the uneven shape by the microprotrusions, and reduces the reflection of incident light in a wide wavelength range by the principle of the moth-eye structure.

[Surface shape of receiving layer]
As shown in FIG. 2, in the antireflection article 1, the surface shape of the receiving layer 4 is prepared so that the thickness of the receiving layer 4 varies in the in-plane direction, and as a result, the base portion of the microprojections 5 is sequentially traced. A curved surface 6 (which is an envelope surface related to the valley bottom of the microprojections 5 and hereinafter referred to as an envelope surface of the valley bottom) 6 is formed so as to exhibit a predetermined swell. In this embodiment, the undulation is such that the surface shape of the envelope surface 6 at the bottom of the valley is equal to the surface shape of the antiglare layer (which is the surface shape of the antiglare film) that scatters reflected light to prevent reflection. Thus, the reflection is further reduced as compared with the conventional case.

  That is, even when antireflection is intended by close arrangement of the microprojections, when the antireflection film is configured simply by arranging microprojections closely on the flat surface, for example, the antireflection film is applied to the panel surface of the image display panel. When the panel surface is observed from an oblique direction after being attached, it is possible to see the reflection of the fluorescent tube on the ceiling even though it is blurred. As a result, this type of antireflection article has room for improvement in reduction of reflection.

  As a result of various studies, as in this embodiment, if the envelope surface 6 at the bottom of the valley is made to have a shape equal to the surface shape of the antiglare layer that scatters reflected light to prevent reflection, the antireflection effect related to the moth-eye structure can be prevented. The anti-glare layer can be added to the anti-reflection effect, thereby reducing the reflection of the anti-reflection article with the moth-eye structure and producing the effect at a wide angle. Can do.

  Here, in the envelope surface 6 of the valley bottom, the average interval Sm (the average value of the interval indicated by the symbol D) is set to 100 μm or more and 600 μm or less, and more preferably 200 μm or more and 500 μm or less. Here, when the average interval Sm is smaller than 100 μm, it approaches the state in which microprotrusions are closely arranged on a flat surface (here, the uneven shape appears on the outermost surface), and the irregular reflection component on the surface increases, This is because the reflection cannot be reduced sufficiently as described in (1). In addition, when the average interval Sm is larger than 600 μm, a rough feeling on the surface or a visually pointed unevenness is felt on the convex portion.

  Further, the envelope surface 6 of the valley bottom is set such that the average inclination angle θa of the concavo-convex surface is 0.1 degrees or more and 1.2 degrees or less, more preferably 0.3 degrees or more and 1.0 degrees or less. Here, when the average inclination angle θa is smaller than 0.1 degree, it approaches a smooth state due to an increase in flatness, or approaches a state in which minute projections are closely arranged below the flat surface, as described above. This is because the reflection cannot be reduced sufficiently. Further, when the uniform inclination angle θa is larger than 1.2 degrees, it is easy to feel a rough feeling on the surface.

  In addition, the envelope surface 6 of the valley bottom is set such that the 10-point average roughness Rz exceeds 0.2 μm and is 1.0 μm or less, and more preferably, the 10-point average roughness Rz is 0.4 μm or more and 0.8 μm or less. . Here, if the 10-point average roughness Rz is too small, it approaches a smooth state, or approaches a state where minute projections are closely arranged under a flat surface, and sufficiently reduces reflection as described above. This is because if the screen is too large, it becomes difficult to visually recognize the screen due to an increase in the diffuse reflection component on the surface, or a rough feeling is likely to be felt on the surface. Thereby, in this embodiment, the envelope surface 6 of the valley bottom can be set to a shape equal to the surface shape of the antiglare layer, and reflection can be effectively reduced.

  The 10-point average roughness Rz is obtained by measuring the surface shape of the envelope surface 6 at the bottom of the valley as a two-dimensional or three-dimensional profile. More specifically, as for the surface shape, a two-dimensional or three-dimensional profile is measured using a scanning probe microscope or an atomic force microscope, and a 10-point average roughness Rz is calculated from profile curve data obtained by the measurement. . By the way, the 10-point average roughness Rz is the average of the deviation values from the largest to the top five deviations, and the absolute value of the smallest to the least five deviations among the deviation values calculated from the average value. Expressed as the sum of the average values.

  Moreover, average space | interval Sm and average inclination | tilt angle (theta) a can be measured, for example using a surface roughness measuring device (model number: SE-3400 / made by Kosaka Laboratory). The average inclination angle θa represents the inclination by the aspect ratio Δa, and θa (degree) = tan−1Δa = tan−1 (the difference between the minimum and maximum portions of each unevenness (corresponding to the height of each convex portion)). (Total / reference length). The “reference length” is, for example, 2.5 mm.

[Shape of microprojection]
Furthermore, in the antireflection article 1, the single-peak microprojections and the multi-peak microprojections 5A and 5B are set to be mixed. Here, the multimodal microprotrusions 5A and 5B are microprotrusions having a plurality of apexes, and the single-peak microprotrusions are microprotrusions having only one apex. Thereby, in this embodiment, the scratch resistance of the antireflection article is improved.

  That is, FIG. 3 is a diagram for explaining the multimodal microprotrusions 5A and 5B and the single-peak microprotrusions. Note that FIG. 3 is a diagram schematically showing for easy understanding, and FIG. 3A is a diagram showing a cross-section by a broken line connecting the vertices of continuous minute protrusions. 3B and 3C, the xy direction is the in-plane direction of the substrate 2, and the z direction is the height direction of the microprojections.

  In the antireflection article 1, many microprotrusions 5 are gradually cut in a cross-sectional area (a plane perpendicular to the height direction (a plane parallel to the XY plane in FIG. 11)) toward the apex away from the base material 2. The cross-sectional area) is reduced, and one vertex is produced. However, in some cases, as if a plurality of microprotrusions were combined, a groove g was formed at the tip, and the apex was two (5A), the apex was three (5B), Furthermore, there can be one having four or more vertices (not shown). The shape of the unimodal microprotrusions 5 can be approximated by a round shape at the top, such as a paraboloid of revolution, or a sharp shape at the apex, such as a cone. On the other hand, the shape of the multimodal microprotrusions 5A and 5B is approximately approximated by a shape in which a groove-shaped recess is cut in the vicinity of the top of the single-peak microprotrusion 5 and the top is divided into a plurality of peaks.

  The multimodal microprotrusions having a plurality of vertices are relatively thicker at the hem than the unimodal microprotrusions, compared to the multimodal microprotrusions. Long perimeter. Thereby, it can be said that the multimodal microprotrusions are superior in mechanical strength to the single-peak microprotrusions. As a result, when multi-peaked microprojections having a plurality of vertices are present, the anti-reflective article has improved scratch resistance compared to the case of using only single-peaked microprojections. Specifically, when external force is applied to the anti-reflective article, the external force is distributed and received at more vertices than when only single-peaked microprotrusions are received. Can be made difficult to damage, thereby reducing local deterioration of the antireflection function and further reducing the occurrence of poor appearance. Moreover, even if a microprotrusion is damaged, the area of the damaged portion can be reduced. In addition, the multi-peak microprojections are higher than the multi-peak micro-projections and lower body parts than the multi-peak micro-projections by first receiving each external force and sacrificing damage. It is possible to prevent wear of small protrusions. This also reduces local deterioration of the antireflection function and further reduces the occurrence of appearance defects.

  Needless to say, although the multimodal microprotrusions can improve the scratch resistance due to their presence, if they do not exist sufficiently, the effect of improving the scratch resistance cannot be fully exhibited. From such a viewpoint, it is desirable that the ratio of the number of multimodal microprotrusions in all the microprotrusions existing on the surface be 10% or more. In particular, in order to sufficiently exhibit the effect of improving the scratch resistance by the multimodal microprotrusions, the ratio of the multimodal microprotrusions is desired to be 30% or more, preferably 50% or more. In addition, by setting the existence ratio of the single-peaked microprotrusions in this manner, sticking can be made difficult to occur, and as a result, deterioration of characteristics due to sticking can be effectively avoided. Furthermore, when unimodal microprojections are mixed with multimodal microprojections, the reflectance can be reduced over a wide wavelength band, as with unimodal microprojections with different aspect ratios. it can.

  FIG. 4 is a photograph showing a plurality of minute protrusions at the apex, FIG. 4 (a) is based on AFM, and FIGS. 4 (b) and (c) are based on SEM. In FIG. 4 (a), a groove g and a microprojection having three vertices, and a microprotrusion having a groove g and two vertices (two-peaked multimodal microprojections) can be seen, and FIG. In FIG. 4 (c), the groove g and the microprotrusions having four vertices (four-peak multimodal microprotrusions) and the groove g and the microprotrusions having two vertices can be seen. One can see microprojections with three vertices (three-peak multimodal microprojections), groove g and microprojections with two vertices.

[Distance between adjacent protrusions]
The microprotrusions produced in the antireflection article 1 are closely arranged so that the distance d between adjacent microprotrusions is equal to or less than the shortest wavelength Λmin (d ≦ Λmin) of the wavelength band of the electromagnetic wave to prevent reflection. In this embodiment, since the main purpose is to improve visibility by arranging the image display panel, the shortest wavelength is set to the shortest wavelength (380 nm) in the visible light region in consideration of individual differences and viewing conditions. The distance d is set to 100 to 300 nm in consideration of variation. The adjacent minute protrusions related to the distance d are so-called adjacent minute protrusions, which are in contact with the hem portions of the minute protrusions, which are the base portions on the base 2 side. In the anti-reflective article 1, the minute protrusions are closely arranged so that when a line segment is formed so as to sequentially follow the valley portions between the minute protrusions, a large number of polygonal regions surrounding each minute protrusion are connected in plan view. Thus, a mesh-like pattern is produced. The adjacent minute protrusions related to the distance d are protrusions that share a part of the line segments constituting the mesh pattern.

  The minute protrusions are defined in more detail as follows. In the antireflection by the moth-eye structure, the effective refractive index at the interface between the transparent substrate surface and the adjacent medium is continuously changed in the thickness direction to prevent reflection. It is necessary to satisfy the following conditions. With respect to the protrusion interval, which is one of these conditions, when the minute protrusions are regularly arranged at a constant period as disclosed in, for example, Japanese Patent Application Laid-Open No. 50-70040 and Japanese Patent No. 4632589, the adjacent spaces are adjacent to each other. The interval d between the minute projections to be performed is the projection arrangement period P (d = P). Thus, when the longest wavelength in the visible light band is λmax and the shortest wavelength is λmin, the minimum necessary condition that can exhibit the antireflection effect at the longest wavelength in the visible light band is Λmin = λmax. P ≦ λmax, and the necessary and sufficient condition that can exhibit the antireflection effect for all wavelengths in the visible light band is Λmin = λmin, and therefore P ≦ λmin.

  The wavelengths λmax and λmin may have some width depending on observation conditions, light intensity (luminance), individual differences, and the like, but are typically λmax = 780 nm and λmin = 380 nm. A preferable condition that can more reliably exhibit the antireflection effect for all wavelengths in the visible light band is d ≦ 300 nm, and a more preferable condition is an oblique direction (at least 45 degrees with respect to the normal of the surface of the substrate 2). D ≦ 200 nm from the viewpoint of reducing the cloudiness when viewed from an angle direction. Note that the lower limit value of the period d is usually d ≧ 50 nm, preferably d ≧ 100 nm, for reasons such as the expression of the antireflection effect and the securing of the isotropic (low angle dependency) of the reflectance. On the other hand, the height H of the protrusion is set to H ≧ 0.2 × λmax = 156 nm (assuming λmax = 780 nm) from the viewpoint of exhibiting a sufficient antireflection effect.

  However, when the minute protrusions are irregularly arranged as in this embodiment, the distance d between the adjacent minute protrusions varies. More specifically, as shown in FIG. 5, when the microprotrusions are not regularly arranged at a constant period when seen in a plan view when viewed from the normal direction of the front surface or the back surface of the base material, the repetition period P of the protrusions In some cases, the distance d between adjacent protrusions cannot be defined, and even the concept of adjacent protrusions is suspicious. Therefore, in such a case, it is calculated as follows.

  (1) That is, first, an in-plane arrangement of projections (planar shape of projection arrangement) is detected using an atomic force microscope (AFM) or a scanning electron microscope (SEM). FIG. 5 is an enlarged photograph actually obtained by an atomic force microscope.

  (2) Subsequently, the maximum point of the height of each protrusion (hereinafter simply referred to as the maximum point) is detected from the obtained in-plane arrangement. As a method for obtaining the maximum point, (a) a method for obtaining the maximum point by sequentially comparing the plane coordinates on the enlarged photograph of the planar view shape and the height data obtained from the corresponding cross-sectional shape, (b) Various methods such as a method of obtaining a local maximum point by image processing of a planar view enlarged photograph obtained by converting the height distribution data in the plane coordinates on the base material obtained by AFM into a two-dimensional image can be applied. FIG. 5 is an enlarged photograph by AFM (image density corresponds to the height), and FIG. 6 is a diagram showing a detection result of the maximum point by processing of image data related to the enlarged photograph shown in FIG. In the figure, each point indicated by a black dot is the maximum point of each protrusion. In this process, image data is processed in advance by a low-pass filter having a Gaussian characteristic of 4.5 × 4.5 pixels, thereby preventing erroneous detection of the maximum point due to noise. Further, a maximum point was obtained in units of 1 nm (= 1 pixel) by sequentially scanning a filter for detecting a maximum value of 8 pixels × 8 pixels.

  (3) Next, a Delaunay diagram (Delaunary Diagram) having the detected maximum point as a generating point is created. Here, Delaunay diagram is obtained by dividing the Voronoi region adjacent to the Voronoi region when the Voronoi division is performed with each local maximum as the generating point, and connecting the adjacent generating points with line segments. This is a net-like figure made up of triangular aggregates. Each triangle is called a Delaunay triangle, and a side of each triangle (a line segment connecting adjacent generating points) is called a Delaunay line. 7 is a diagram in which the Delaunay diagram (represented by white line segments) obtained from FIG. 6 is superimposed on the original image of FIG. The Delaunay diagram has a dual relationship with the Voronoi diagram. Voronoi division means that a plane is divided by a net-like figure made up of a closed polygon aggregate defined by perpendicular bisectors of line segments (Droney lines) connecting between adjacent generating points. A network figure obtained by Voronoi division is a Voronoi diagram, and each closed region is a Voronoi region.

  (4) Next, the frequency distribution of the line segment length of each Delaunay line, that is, the frequency distribution of the distance between adjacent maximum points (hereinafter referred to as the distance between adjacent protrusions) is obtained. FIG. 8 is a frequency distribution histogram prepared from the Delaunay diagram of FIG. In addition, as shown by reference numerals 5A and 5B in FIG. 5, when a concave portion such as a groove exists at the top of the projection, or when the top is split into a plurality of peaks, from the obtained frequency distribution, A frequency distribution is created by removing data resulting from a fine structure having a concave portion at the top of the protrusion and a fine structure in which the top is split into a plurality of peaks, and selecting only the data of the protrusion main body itself.

  Specifically, in the fine structure in which there is a concave portion on the top of the protrusion, or in the fine structure related to a multi-peak microprotrusion in which the top is divided into a plurality of peaks, the single peak property that does not have such a fine structure From the numerical range in the case of a microprotrusion, the distance between adjacent maximum points is clearly greatly different. Thus, by removing the corresponding data using this feature, only the data of the projection body itself is selected and the frequency distribution is detected. More specifically, for example, about 5 to 20 adjacent single-peaked microprojections are selected from an enlarged photograph of the microprojections (group) in plan view as shown in FIG. 5, and the distance between adjacent maximum points is selected. The value of is sampled and the value clearly deviates from the numerical range obtained by sampling (usually data whose value is ½ or less of the average distance between adjacent maximum points obtained by sampling) To detect the frequency distribution. In the example of FIG. 8, data having a distance between adjacent maximal points of 56 nm or less (the leftmost small mountain indicated by arrow A) is excluded. FIG. 6 shows a frequency distribution before such exclusion processing is performed. Incidentally, such exclusion processing may be executed by setting the above-described maximum inspection filter.

(5) The average value d _AVG and the standard deviation σ are obtained from the frequency distribution of the distance d between adjacent protrusions thus obtained. Here, when the frequency distribution obtained in this way is regarded as a normal distribution and the average value d _AVG and the standard deviation σ are obtained, the average value d _AVG = 158 nm and the standard deviation σ = 38 nm are obtained in the example of FIG. As a result, the maximum value of the distance d between adjacent protrusions is set to dmax = d _AVG + 2σ, and in this example, dmax = 234 nm.

The same method is applied to define the height of the protrusion. In this case, a relative height difference of each local maximum point position from a specific reference position is acquired from the local maximum point obtained by the above (2), and is histogrammed. FIG. 9 is a diagram showing a histogram of the frequency distribution of the protrusion height H with the protrusion root position thus obtained as a reference (height 0). The average value _HAVG of the protrusion height and the standard deviation σ are obtained from the frequency distribution based on the histogram. Here in the example of FIG. 9, the average value _H AVG = 178 nm, the standard deviation sigma = 30 nm. Thus in this example, the height of the projections is an average value _H AVG = 178 nm. In the histogram of the protrusion height H shown in FIG. 9, in the case of a multi-peak microprotrusion, the plurality of data are mixed for one protrusion because of having a plurality of vertices. Therefore, in this case, the frequency distribution is obtained by adopting the vertex having the highest height from among the plurality of vertices belonging to the same microprotrusion as the protuberance.

  In addition, the reference position when measuring the height of the protrusion described above is based on the valley bottom (minimum point of height) between the adjacent minute protrusions as a reference of height 0. However, as described above with reference to FIG. 2, for example, when the height of the valley bottom has undulation with a period larger than the distance between the adjacent protrusions of the minute protrusions, ) First, the average value of the height of each valley bottom measured from the front surface or the back surface of the base material 2 is calculated within an area sufficient for the average value to converge. (2) Next, a surface having the height of the average value and parallel to the front surface or the back surface of the substrate 2 is considered as a reference surface. (3) Then, the height of each microprotrusion from the reference surface is calculated by setting the reference surface to a height of 0 again.

If the protrusions are irregularly arranged, when this way the maximum value of the adjacent protrusions distance obtained by dmax = d AVG ₊ 2σ, average H _AVG height of projections are arranged regularly It has been found necessary to satisfy the above conditions. Specifically, the condition of the distance between the microprotrusions that exhibits the antireflection effect is dmax ≦ Λmin. The minimum necessary condition that can exhibit the antireflection effect at the longest wavelength in the visible light band is Λmin = λmax, and therefore dmax ≦ λmax, and the antireflection effect can be achieved for all wavelengths in the visible light band. The necessary and sufficient condition is Λmin = λmin, and therefore dmax ≦ λmin. A preferable condition that can more reliably exhibit the antireflection effect for all wavelengths in the visible light band is dmax ≦ 300 nm, and a more preferable condition is dmax ≦ 200 nm. Also, dmax ≧ 50 nm is usually satisfied and dmax ≧ 100 nm is preferable because of the antireflection effect and ensuring the isotropic (low angle dependency) of the reflectance. The height of the protrusion is set to _HAVG ≧ 0.2 × λmax = 156 nm (assuming λmax = 780 nm) in order to exhibit a sufficient antireflection effect.

5 to 9, dmax = 234 nm ≦ λmax = 780 nm, and it can be seen that the antireflection effect can be sufficiently achieved by satisfying the condition of dmax ≦ λmax. In addition, since the shortest wavelength λmin in the visible light band is 380 nm, it can be seen that the sufficient condition dmax ≦ λmin for exhibiting the antireflection effect in all visible light wavelength bands is also satisfied. When the average protrusion the height _H AVG = 178 nm Also, the average projection height _{H AVG} ≧ 0.2 × λmax = _156nm becomes (as the longest wavelength .lambda.max = 780 nm in the visible light wavelength band), realizing a sufficient antireflection effect It can be seen that the conditions regarding the height of the protrusions to satisfy are also satisfied. Note since the standard deviation sigma = 30 _nm, since the relationship between the _{H AVG -σ = 148nm <0.2 ×} λmax = 156nm is satisfied, statistically, more than 50% of the total protrusions, 84% or less It can be seen that the condition of the height of the protrusion (178 nm or more) is satisfied. In addition, from the observation result by AFM and SEM and the analysis result of the height distribution of the microprojections, the multi-peak microprojections tend to be generated more frequently in the microprojections having a higher height than the microprojections having a relatively low height. It has been found.

〔Measurement result〕
10 and 11 are charts showing the evaluation results for the case where the antireflection article (Example) according to this embodiment and the comparative example are arranged on the panel surface of the image display panel. Here, the example (envelope surface + microprojection) includes the microprojections provided for the measurement in FIGS. 8 and 9, the average interval Sm of the irregularities on the envelope surface 6 is 100 μm, the average inclination angle θa is 1.2 degrees, The 10-point average roughness Rz is 1.0 μm. In Comparative Example 1 (flat surface + minute protrusion), the average interval Sm, the average inclination angle θa, and the 10-point average roughness Rz of the envelope surface 6 at the bottom of the valley are flat compared to the above-described embodiment. Except for the configuration related to the envelope surface 6 of the valley bottom, this is an antireflection article having only the moth-eye structure configured the same as in Example 1. Comparative Example 2 (envelope surface only (outside the scope of the embodiment) + microprojection) is an antireflection film that provides antireflection only by the uneven surface having the same surface shape as the envelope surface of the valley bottom according to Example 1. Further, Comparative Example 3 (envelope surface (outside the scope of the embodiment) + microprojection) is an uneven surface with an average interval Sm of 90 μm, an average inclination angle θa of 1.5 degrees, and an average roughness Rz of 1.5 μm. Comparative Example 4 (envelope surface (outside the scope of the embodiment) + microprojection) is shown on the valley bottom envelope surface 6 having the same surface shape as the uneven surface of Comparative Example 3. 8 and FIG. 9 are provided with minute projections used for the measurement.

  The low reflection performance is an evaluation of the reflectance in the front direction, and the regular reflection property is an evaluation of the regular reflectance of incident light with an oblique incident angle of 45 degrees. Here, ◎ indicates that the reflectance is low enough for practical use when placed on the panel surface of the image display panel, and ○ indicates that it is sufficiently practical for use, although not as good as ◎. Indicates low reflectivity. The x mark indicates a case where the reflectivity is large and is not practically used, and the Δ mark is a case where the reflectivity is not as great as in the case of the x mark, but is determined to be insufficient for practical use.

  Reflection is an evaluation of reflection when observed from the front direction, and oblique reflection is an evaluation when observed from the oblique direction. Here, ◎ indicates that the reflection of a light source such as a fluorescent lamp is hardly recognized. ○ indicates that the reflection of a fluorescent lamp is sufficiently reduced to be practically used. It is a case where it can grasp. The Δ mark and the X mark are cases where there is room for improvement in the reflection, and the determination is based on the size of the room for improvement. The angle dependency related to the reflection is to evaluate the change in the degree of reflection due to the change in the viewing angle. When this change is small, the angle dependency is small, and when the change is large, the angle dependency is Yes. "

  The glossy black expression is an evaluation of the appearance of the display screen. The ◯ mark indicates that the surface is transparent and the display screen can be seen in black. The X mark indicates that the surface is transparent. This is a case where the display screen appears whitish. The overall performance is an evaluation based on a comprehensive judgment of these evaluations. The symbol ◎ indicates that the various performances are sufficiently superior for practical use, and the symbol Δ indicates that some performance is insufficient. In this case, the mark “X” indicates that most of the performance is insufficient.

  According to the comparison result of FIG. 10, the defect related to the antireflection article (Comparative Example 1) having only the moth-eye structure can be improved by setting the envelope surface of the valley bottom, and the reflection can be sufficiently reduced. It can be seen that the dependency can be reduced, and the display screen can be set to black with transparency.

  11 and FIG. 10, when the shape of the envelope surface of the valley bottom deviates from the above-described range, even when the combination with the moth-eye structure is used (Comparative Example 4), the envelope surface 6 of the valley bottom is Even when the surface shape alone is used (Comparative Example 3), it can be seen that the reflection cannot be reduced sufficiently, and the display screen is also white.

[Detailed examination of reflection]
FIG. 12A is a diagram for explaining a measurement system used for evaluation of reflection. In this embodiment, reflection was evaluated in more detail using the measurement system shown in FIG. Here, this measurement system uses a linear light source to create a reference light for reflection measurement, this reference light is obliquely incident on the surface of the sample, and the light source image formed on the surface of this material is converted to the correct reference light. Take a picture with a digital camera from the reflection direction and evaluate it.

  More specifically, in this measurement system, a light-shielding plate having a slit S (slit width 2 mm) is provided in front of a light source (not shown) that emits parallel light, and the extension direction of the slit S is parallel to the sample surface. The linear light source is formed by arranging the light shielding plate so that the light shielding plate is orthogonal to the optical axis of the reference light obliquely incident on the sample. When the sample surface is observed from the regular reflection direction of the reference light in this way, as shown in FIG. 12B, a light source image by reflection is formed on the sample surface. The image cannot be recognized.

  In this embodiment, the incident angle θ of the reference light is sequentially changed step by step, and a light source image on the sample surface is photographed from the regular reflection direction of the reference light at each incident angle θ. Further, as indicated by the symbol L, the gradation of the photographing result was sequentially measured and evaluated in the direction across the light source image. In the gradation, the luminance level is clipped according to a certain determination reference value, and the clipped luminance level is expressed as 256 gradation, and the black luminance level is expressed as 0 gradation.

  In this embodiment, since all the samples can be observed from the imaging result, various parameters relating to the digital camera (for example, aperture, exposure time, etc.) are set and photographed. As for the amount of light, it is difficult to measure due to saturation. As a result, in the measurement results described later, it is difficult to measure the amount of regular reflection component that is greater than the criterion value.

  However, for the light amount measurement above the determination reference value, by adding the following improvement to the photographing method, the non-measurable area can be reduced and the difference between the light source images of the individual embodiments can be made clearer. That is, (1) The aperture value and shutter speed of the digital camera are adjusted so that all the samples are reflected from the light source image with high luminance to the sample surface with low luminance. (2) By taking a high dynamic range image with a wide dynamic range, the range of luminance levels that can be imaged can be expanded, and the determination reference value can be set higher. Thereby, the non-measurable area | region of a sample can be reduced and the difference in the specular reflection between samples can be made clearer. (3) Measure specular reflection energy on the sample surface using a goniophotometer. Thereby, the specular reflection light intensity of each sample can be compared in absolute value.

  FIG. 13 is a diagram illustrating measurement results of a sample for comparative study. This sample is so-called black acrylic whose surface is a mirror surface, and the horizontal axis is a position in a direction crossing the light source image. According to this comparative measurement result, even when the incident angle θ is variously changed, the gradation is abruptly determined at the position corresponding to the edge of the light source image (the above-mentioned 256 gradations). In this measurement setting range, since the focus was on improving reflection, it has risen beyond the upper limit (which is an unmeasurable area), and the occurrence of significant reflection can be confirmed.

  FIG. 14 is a diagram illustrating measurement results of Comparative Example 1. In this case, compared with the measurement result of the comparative examination sample, the range in which the gradation rises more than the determination reference value is narrow, so that the visible light source image is observed more thinly than in the example of FIG. I understand that Further, the gradation of the peak gradually decreases as the incident angle θ decreases, and the peak value itself is smaller than that in the example of FIG. 13, so that the effect of reducing the reflection can be seen. However, due to the presence of a sharp rise in gradation, the light source image itself can be seen. These show that there is still room for improvement in reducing reflection.

  FIG. 15 is a diagram illustrating measurement results of Comparative Example 4. In this case, it can be seen that the light source image is blurred because the rapid change in gradation is reduced as compared with the example of FIG. 14, and thus the effect of making the valley envelope surface uneven can be seen. . However, the peak value at each incident angle θ is not much different from that in the example of FIG. 14, and it can be seen that there is no change in the brightness of the light source image although it is blurred.

  FIG. 16 is a diagram illustrating measurement results of the example. In this case, it can be seen that the sharp change in gradation is alleviated compared to the example of FIG. 15, and that the light source image is observed more blurry, thereby making the valley envelope uneven by the curved shape described above. You can see the effect of the shape. Further, the peak value at each incident angle θ is further reduced as compared with the examples of FIGS. 14 and 15, and it is understood that the light source image is more difficult to understand. In addition, the comparison result by the absolute value light quantity measured separately and the measurement result of an Example by the comparison with the measurement result by the relative value on the basis of 0 gradation in FIGS. It is found that the reflection cannot be visually recognized with respect to 50 gradation or less by the measurement system according to this embodiment. Accordingly, in FIG. 16, the gradation area larger than 50 gradations is much smaller than the measurement results of FIGS. 13 to 15, and even when the gradation is 50 gradations or more, the rising from 50 gradations is achieved. It can be seen that, by being small, the reflection can be remarkably suppressed as compared with the conventional case.

  FIGS. 17 and 18 are graphs summarizing the measurement results of FIGS. 13 to 16 for the incident angles θ = 10 degrees and 80 degrees. Reference numeral L1 indicates an example, and reference numerals L2, L3, and L4 indicate measurement results of Comparative Example 4, Comparative Example 1, and a sample for comparative study. According to FIGS. 17 and 18, the effect of reducing the reflection in the embodiment can be confirmed by comparison with Comparative Example 1 or the like.

〔Manufacturing process〕
FIG. 19 is a diagram illustrating a manufacturing process of the antireflection article 1. In the manufacturing process 10, in the resin supplying process, an uncured and liquid acrylate-based UV curable resin constituting the microprojection-shaped receiving layer 4 is applied to the belt-shaped substrate 2 by the die 12. In addition, about application | coating of an ultraviolet curable resin, not only the case by the die | dye 12 but various methods are applicable. Subsequently, in this manufacturing process 10, the substrate 2 is pressed and pressed onto the peripheral side surface of the roll plate 13 which is a mold for shaping the antireflection article by the pressing roller 14, and thereby the substrate 2 is uncured. A liquid ultraviolet curable resin is brought into close contact, and the concave and convex portions formed on the peripheral side surface of the roll plate 13 are sufficiently filled with the ultraviolet curable resin. In this state, in this manufacturing process, the ultraviolet curable resin is cured by irradiation with ultraviolet rays, and thereby a microprojection group is produced on the surface of the substrate 2. In this manufacturing process, the substrate 2 is peeled off from the roll plate 13 through the peeling roller 15 together with the cured ultraviolet curable resin. In the production process 10, an anti-reflection article 1 is produced by producing an adhesive layer or the like on the substrate 2 as necessary, and then cutting it into a desired size. Accordingly, the antireflection article 1 is mass-produced efficiently by sequentially molding the fine shape produced on the peripheral side surface of the roll plate 13 which is a mold for molding on the long base material 2 made of a roll material. The

[Roll plate making process]
FIG. 20 is a perspective view showing the configuration of the roll plate 13. The roll plate 13 is formed by repeating the anodizing treatment and the etching treatment after the surface shape of the peripheral side surface of the base material, which is a cylindrical metal material, is a curved shape corresponding to the envelope surface 6 of the valley bottom. A fine uneven shape is formed, and this fine uneven shape is formed on the base material 2 together with the curved surface shape related to the envelope surface 6 of the valley bottom. For this reason, as for the roll plate 13, a columnar or cylindrical member in which a high purity aluminum layer is provided at least on the peripheral side surface is applied to the base material. The surface shape of the aluminum layer is a curved shape corresponding to the envelope surface 6 of the valley bottom. More specifically, in this embodiment, a hollow stainless steel pipe is applied to the base material, and a high-purity aluminum layer has a curved shape corresponding to the envelope surface 6 of the valley bottom, either directly or through various intermediate layers. Provided. In addition, it may replace with a stainless steel pipe and may apply pipe materials, such as copper and aluminum. In the roll plate 13, fine holes are densely formed on the peripheral side surface of the base material by repeating the anodizing treatment and the etching treatment, and the fine holes are dug, and the diameter of the roll plate 13 increases as it approaches the opening. The concavo-convex shape is produced by gradually increasing the diameter of the fine holes. As a result, the roll plate 13 is closely formed with fine holes whose diameter gradually decreases in the depth direction, and the diameter of the antireflection article 1 gradually decreases as it approaches the top corresponding to the fine holes. A fine concavo-convex shape is produced by a large number of fine protrusions.

  FIG. 21 is a diagram showing a manufacturing process of the roll plate 13. In this manufacturing process, the peripheral side surface of the base material is made into a super mirror surface by an electrolytic composite polishing method that combines electrolytic elution action and abrasion action by abrasive grains (electrolytic polishing).

  Subsequently, this step is provided with a curved surface shape corresponding to the envelope surface 6 of the valley bottom in the base layer manufacturing step, and further, a base layer made of an aluminum layer is formed on the peripheral side surface of the base material, thereby the peripheral side surface of the base material Is a curved surface shape corresponding to the envelope surface 6. Subsequently, in this process, anodizing processes A1,..., AN, etching processes E1,..., EN are alternately repeated to form fine holes in the underlayer, and thereby roll plate 13 is manufactured.

  More specifically, in this manufacturing process, in the anodic oxidation process A1,..., AN, a fine hole is produced on the peripheral side surface of the base material by an anodic oxidation method, and the produced fine hole is further dug. Here, in the anodic oxidation step, various methods applied to the anodic oxidation of aluminum can be widely applied, for example, when a carbon rod, a stainless steel plate, or the like is used for the negative electrode. Further, as the solution, various neutral and acidic solutions can be used, and more specifically, for example, sulfuric acid aqueous solution, oxalic acid aqueous solution, phosphoric acid aqueous solution and the like can be used. In the manufacturing steps A1,..., AN, the fine holes are formed in shapes corresponding to the target depth and the shape of the fine protrusions, respectively, by managing the liquid temperature, the applied voltage, the time for anodization, and the like.

  In the subsequent etching step E1,..., EN, the base material is immersed in an etching solution, the hole diameter of the fine hole produced and dug in the anodizing step A1,. These fine holes are shaped so that the hole diameter becomes smaller and smoother. As the etching solution, various etching solutions that are applied to this type of treatment can be widely applied. More specifically, for example, a sulfuric acid aqueous solution, an oxalic acid aqueous solution, a phosphoric acid aqueous solution, or the like can be used. As a result, in this manufacturing process, the anodizing process and the etching process are alternately performed a plurality of times, so that fine holes for forming are formed on the peripheral side surface of the base material. The anodizing solution itself such as an oxalic acid aqueous solution used in the anodizing treatment functions as an etching solution if it is brought into contact with the base material without applying a voltage. Therefore, the anodizing treatment solution and the etching solution are the same solution, and the anodizing treatment is performed by sequentially applying a predetermined voltage for a predetermined time while the base material is immersed in a bath containing the same solution, and no voltage is applied. Etching can also be performed by immersing in a predetermined time.

  FIG. 22 is a flowchart showing in detail the underlayer manufacturing process, and FIG. 23 is a diagram showing a detailed configuration according to this flowchart. As shown in FIG. 23A, in the underlayer manufacturing process, first, a curved surface shape corresponding to the envelope surface of the valley bottom is manufactured on the peripheral side surface of the base material 21 by the uneven surface manufacturing process. Here, the curved surface shape of the envelope surface of the valley bottom is the same shape as the surface shape of the antiglare layer that scatters reflected light to prevent reflection, so that in the uneven surface preparation process, antiglare in this type of antireflection film By applying the technique used for the production of the layer to produce the irregular surface layer 22 on the peripheral side surface of the base material 21, a curved surface shape corresponding to the envelope surface of the valley bottom is produced.

  As a method for producing such an uneven surface layer 22, for example, a method disclosed in Japanese Patent No. 5170634, 1) having an uneven shape using an anti-glare composition obtained by adding fine particles to a resin. A method for forming an antiglare layer, 2) a method for forming an antiglare layer having a concavo-convex shape using a composition for antiglare without adding fine particles, and 3) providing a concavo-convex shape A method of forming an antiglare layer using the treatment to be applied can be applied. Thereby, in this embodiment, after coating a coating liquid with a die | dye etc., processing, such as hardening, is performed and the uneven surface layer 22 is produced. The uneven surface layer 22 preferably has a thickness of 0.5 μm or more and 27 μm or less, more preferably 1 μm or more and 12 μm or less.

  The uneven surface layer 22 is produced by a shape corresponding to the envelope surface 6 of the valley bottom (inverted shape), so that the average interval Sm is 100 μm or more as described above for the uneven shape of the envelope surface 6. The surface shape is 600 μm or less, the average inclination angle θa is 0.1 ° or more and 1.2 ° or less, and the 10-point average roughness Rz is more than 0.2 μm and 1.0 μm or less.

  Subsequently, in this manufacturing process, an intermediate layer 23 is formed on the surface of the uneven surface layer 22 by electroforming, and then an aluminum layer 24 to be subjected to an anodic oxidation process is formed on the surface of the intermediate layer 23 by sputtering (FIG. 23 ( B)). Here, the intermediate layer 23 is provided for the purpose of strengthening the adhesion between the aluminum layer 24 and the concavo-convex surface layer 22, and various materials applicable to this type of treatment can be applied. Nickel is applied. If necessary, the intermediate layer may be produced by a method such as CVD (Chemical Vapor Deposition) other than electroforming, and the intermediate layer may be omitted if practically sufficient.

  Thereby, in this embodiment, a base layer is manufactured by the laminated body of the uneven surface layer 22, the intermediate layer 23, and the aluminum layer 24, and microholes corresponding to the microprojections 5 are formed in the base layer, and the roll plate 13 is formed. It is manufactured (FIG. 23C).

[Details of anodizing and etching]
FIG. 24 is a diagram showing in detail the anodic oxidation process and the etching process in FIG. 21 in the case where such single-peak microprojections and multi-peak microprojections are mixed. Here, the applied voltage of the anodizing treatment is proportional to the pitch of the fine holes to be produced. In practice, however, the pitch of the fine holes varies depending on the grain boundaries of aluminum used for processing. However, in FIG. 24, it is assumed that there is no such variation, and that the fine holes are produced by regular arrangement. FIGS. 24A to 24E are a plan view and a corresponding cross-sectional view cut out along the line aa, respectively, of the fine holes produced by the respective steps.

  First, in this embodiment, after the first anodizing process is performed with the low applied voltage V1, an etching process (hereinafter, referred to as a first process as appropriate) is performed, whereby FIG. As shown, a fine hole f1 with a basic pitch according to this low applied voltage V1 is produced. Here, the first anodic oxidation treatment is to produce a trigger for the subsequent anodic oxidation on the surface of the aluminum layer. In this case, the etching process in the first step may be omitted as necessary.

  Subsequently, in this embodiment, the second anodic oxidation process is performed with the applied voltage V2 (V2> V1) higher than that during the first anodic oxidation, and then the etching process is performed (hereinafter referred to as a second process as appropriate). ). Here, in this case, as shown in FIG. 24 (b), the applied voltage related to the second anodizing treatment among the fine holes f1 produced by the first anodizing treatment by increasing the applied voltage. Only the fine hole corresponding to the voltage is dug in the depth direction (indicated by reference numeral f2) and etched. Accordingly, if the applied voltage is varied in two steps, for example, fine holes having different depth distributions can be mixed in the second step.

  Subsequently, in this embodiment, the third anodic oxidation process is performed with the applied voltage V3 (V3> V2) higher than that during the second anodic oxidation, and then the etching process is performed (hereinafter referred to as a third process as appropriate). (FIG. 24 (c)). Here, the third step is a step for producing fine holes having different pitches. Therefore, in this step, the applied voltage is gradually increased from the applied voltage V2 in the second anodic oxidation step. Here, when the increase in the applied voltage is executed discretely (stepwise), the height distribution of the microprotrusions can be set discretely, and microholes having different depth distributions can be mixed. Further, when the increase in the applied voltage is continuously changed, the depth distribution can be set to a normal distribution.

  Further, in this third step, the application time of the specific voltage related to the anodic oxidation and the time of the etching process are set longer than those in the first and second steps, so that the first step, The fine holes f1 and f2 formed in the two steps are combined with the fine holes f1 and f2 so as to form a substantially flat fine hole at the bottom.

  Subsequently, in this embodiment, after performing the fourth anodic oxidation process with the applied voltage V4 (V4> V3) higher than that in the third anodic oxidation, the etching process is performed (hereinafter, referred to as a fourth process as appropriate). (FIG. 24D). Here, the fourth step is a step for producing a fine hole with a pitch according to a target interprotrusion interval, and the applied voltage V4 is a voltage corresponding to this pitch. In this fourth step, by increasing the applied voltage, a part of the fine hole dug deeply in the third step is further dug further, and the dug fine hole becomes a unimodal microprotrusion. The corresponding fine hole f4 is obtained.

  Subsequently, in this embodiment, the fifth anodic oxidation process is performed by the applied voltage V1 in the first process, and then the etching process is performed (FIG. 24E). Here, in the fifth step, a fine hole whose bottom surface is flattened by the third step and is not affected by the anodizing treatment of the fourth step, a fine hole is formed on the bottom surface. A plurality of microholes f5 for multi-peak protrusions are formed. Here, by adjusting the magnitude of the applied voltage V1 in the fifth step, the number of fine holes f5 formed on the bottom surface can be increased or decreased.

  In this series of steps, the fine holes f1 and f2 having different depths produced in the first and second steps are dug in the third step to produce a substantially flat microprojection f3 on the bottom surface. In the fourth step, a fine hole related to the single-peaked microprojection is formed, and in the fifth step, the bottom surface of the microprojection f3 having a flat bottom surface is processed to form a microhole related to the single-peaked microprojection. By controlling the applied voltage, the processing time, the etching processing time, etc. of the anodizing treatment according to these first to fourth steps, the depth of the fine hole produced in each step is controlled. By doing so, it is possible to control the height distribution of the microprojections and the height distribution of the multimodal microprojections. Needless to say, these first to fifth steps may be omitted, repeated, or integrated as necessary.

  According to the above configuration, the anti-reflection function by the moth-eye structure can be added with the function of preventing reflection by the curved shape of the envelope surface of the valley bottom, and the reflection can be efficiently reduced. With respect to the antireflection article having the structure, the reflection can be further reduced as compared with the conventional case.

  In addition, according to the above-described configuration, a production mold (roll plate), a mold, and a mold suitable for production of an antireflection article with a moth-eye structure that reduces reflection by setting the curved surface shape of the envelope surface of the valley bottom as described above A method for producing an antireflective article can be provided. That is, according to this embodiment, the production method of the antiglare layer that scatters the reflected light to prevent reflection can be applied to produce the undulation on the inclusive surface of the valley bottom, thereby producing the antiglare layer production method. Can be effectively used to effectively reduce the reflection. In particular, in such an antiglare layer, various methods for setting the surface roughness and the like are provided, and thereby, the curved surface shape of the envelope surface of the valley bottom can be produced in a desired shape.

  Also, in this embodiment, by making a base layer in the base material and making fine holes, it is possible to effectively avoid changes in the curved shape of the envelope surface due to production, etc., ensuring sufficient durability. Can be produced in roll version.

[Second Embodiment]
FIG. 25 is a diagram for explaining a roll plate manufacturing process according to the second embodiment of the present invention. This embodiment has the same configuration as that of the first embodiment except that the configuration related to the manufacturing process of the roll plate is different.

  Here, in this embodiment, the uneven surface layer 22 is produced on the surface of the support 31 in the same manner as described above for the first embodiment, and thereby the surface of the support 31 corresponds to the envelope of the valley bottom. A curved surface shape is produced (FIG. 25A). Here, in this embodiment, the support 31 is a member that is removed by a process that will be described later, so that various substrates such as a transparent film that is used for producing an antiglare film can be applied, but an opaque film material. Various sheet materials, plate materials and the like can be widely applied. Moreover, you may apply the anti-glare film etc. by which the same uneven surface is produced instead of producing the uneven surface layer 22 on the surface of the support body 31 in this way.

  Subsequently, in this step, an intermediate layer 23 is formed on the surface of the uneven surface layer 22 by electroforming (FIG. 25B). Here, the intermediate layer 23 in this step is a support layer for use in transferring the surface shape of the concavo-convex surface layer 22. In this embodiment, various materials, for example, made of nickel, can be widely applied. In addition, various methods such as CVD can be applied instead of electroforming.

  Subsequently, in this step, the intermediate layer 23 is peeled off from the uneven surface layer 22, and an aluminum layer 24 is produced by sputtering on the surface that was on the uneven surface layer 22 side to be peeled off (FIG. 25C). Instead of this, an aluminum layer may be formed on the opposite side surface. In this case, the aluminum layer is drawn from the uneven surface layer 22 after the aluminum layer is formed or after a microhole described later is formed. In these cases, the transfer support layer may be omitted if practically sufficient.

  Subsequently, in this step, fine holes corresponding to the fine protrusions are formed on the surface of the aluminum layer 24 by repeating the anodizing treatment and the etching treatment (FIG. 25D). Subsequently, the laminate produced in this manner is separately placed on the surface of a base material having a smoothed surface, whereby a roll plate is produced.

  According to this embodiment, the uneven shape related to the shape of the envelope surface of the valley bottom is transferred to produce the mold for molding, thereby transferring the uneven shape related to the existing anti-glare film material to the production mold. A roll version can be produced.

[Other Embodiments]
The specific configuration suitable for the implementation of the present invention has been described in detail above. However, the present invention can be variously modified from the configuration of the above-described embodiment without departing from the spirit of the present invention, and further the conventional configuration. Can be combined.

  That is, in the above-described embodiment, in the first embodiment, the case where the base layer is formed on the surface of the base material and the roll plate is manufactured is described. However, the present invention is not limited to this, and the existing anti-glare film material is used. After producing the aluminum layer, fine holes may be produced, and then this film material may be disposed on the base material surface. Alternatively, an existing anti-glare film material may be disposed on the surface of the base material, and then an aluminum layer may be produced, and then a fine hole may be produced.

  Moreover, although the above-mentioned embodiment described the case where the anti-reflective article by a film shape was produced by the shaping process using a roll plate, this invention is not limited to this, The transparent base material which concerns on the shape of an anti-reflective article Depending on the shape, for example, when creating an antireflection article by processing a sheet using a shaping mold with a specific curved shape, such as a flat plate, the process related to the shaping process, the mold is the antireflection article It can change suitably according to the shape of the transparent base material which concerns on a shape.

  In the above-described embodiment, the case where an acrylate-based ultraviolet curable resin is applied to the shaping resin has been described. However, the present invention is not limited thereto, and various ultraviolet curable resins such as epoxy-based and polyester-based resins, or Also when using various materials such as acrylate-based, epoxy-based, polyester-based electron beam curable resins, urethane-based, epoxy-based, polysiloxane-based thermosetting resins, and various types of curing resins The present invention can be widely applied. Further, for example, the present invention can be widely applied to the case of shaping by pressing a heated thermoplastic resin.

  Further, in the above-described embodiment, as shown in FIG. 1, microprojections are formed on the receiving layer 4 of the laminate formed by laminating the receiving layer (ultraviolet curable resin layer) 4 on one surface of the substrate 2. The groups 5, 5A, 5B,... Are shaped and the receiving layer 4 is cured to form the antireflection article 1. The layer structure is a two-layer laminate. However, the present invention is not limited to such a form. Although not shown, the antireflection article 1 of the present invention is a single layer in which the microprojections 5, 5A, 5B,... Are directly formed on one surface of the substrate 2 without interposing another layer. It may be a configuration. Alternatively, one or more intermediate layers on one surface of the substrate 2 (layers that improve substrate surface performance such as interlayer adhesion, coating suitability, surface smoothness, etc. Also referred to as primer layer, anchor layer, etc. .) May be formed, and a laminate of three or more layers in which the microprotrusions 5, 5A, 5B,... Are formed on the surface of the receptor layer may be used.

Further, in the above-described embodiment, as shown in FIG. 1, the microprojections 5, 5A, 5B,... Are formed only on one surface of the base material 2 (directly or via another layer). However, the present invention is not limited to such a form. The microprojection groups 5, 5A, 5B,... May be formed on both surfaces of the substrate 2 (directly or via other layers).
Although not shown, in the antireflection article 1 of the present invention as shown in FIG. 1 and the like, the surface opposite to the surface on which the microprojections are formed of the substrate 2 (the lower surface of the substrate 2 in FIG. 1). Various adhesive layers are formed on the adhesive layer, and a release film (release paper) is laminated on the surface of the adhesive layer so as to be peelable. In such a form, the release film is peeled and removed to expose the adhesive layer, and the antireflection article 1 of the present invention can be laminated and laminated on the desired surface of the desired article by the adhesive layer. The antireflection performance can be easily imparted to a desired article. As the adhesive, various types of known adhesive forms such as a pressure-sensitive adhesive (pressure-sensitive adhesive), a two-component curable adhesive, an ultraviolet curable adhesive, a thermosetting adhesive, and a hot melt adhesive can be used. .

  Although not shown, in the antireflection article 1 of the present invention as shown in FIG. 1 etc., the microprojections 5, 5 A, 5 B,... The protective film may be peeled and removed at an appropriate time after carrying, carrying, buying and selling, post-processing or construction. In such a form, it is possible to prevent the antireflection performance from being deteriorated due to damage or contamination of the microprojection group during storage, transportation and the like.

  Further, in the above-described embodiment, the case where the fine hole is produced by repeating the anodizing treatment and the etching treatment has been described. However, the present invention is not limited to this, and the case where the fine hole is produced by applying a photolithography technique. Can also be widely applied.

  Moreover, although the above-mentioned embodiment described the case where the anti-reflective article by a film shape is arrange | positioned to the image display panel which concerns on an anti-reflective film, this invention is applicable not only to this but to various uses. Specifically, it should be applied to applications that are placed on the back surface (image display panel side) of the surface side member such as a touch panel, various window materials, various optical filters, etc. installed on the screen of the image display panel through a gap. Can do.

  In addition, it is arranged on the glass plate surface (external side) used for the store show window and product display box of the store, the display window and display box of the exhibition of the museum, or both of the front and back surfaces (product or display side). May be. In this case, it is possible to improve the visibility for customers and spectators of products, artworks, etc. by preventing light reflection on the surface of the glass plate.

  Further, the present invention can be widely applied to the case where the lens or prism is used on various optical devices such as glasses, a telescope, a camera, a video camera, a gun sighting mirror (sniper scope), binoculars, a periscope, and the like. In this case, the visibility by preventing light reflection on the lens or prism surface can be improved. Furthermore, it can also be applied to the case where it is arranged on the surface of a printed part (characters, photos, drawings, etc.) of a book to prevent light reflection on the surface of characters and the like and improve the visibility of characters and the like. In addition, it should be placed on the surface of signs (posters, posters, various other stores, streets, exterior walls, etc.) (road guidance, maps, smoking cessation, entrances, emergency exits, no entry, etc.) to improve visibility. Can do. In addition, a light entrance surface of a window material for a lighting fixture using an incandescent bulb, light emitting diode, fluorescent lamp, mercury lamp, EL (electroluminescence), etc. By arranging it on the side, it is possible to prevent the light reflection of the light incident surface of the window material, reduce the reflection loss of the light source light, and improve the light utilization efficiency. Furthermore, it can arrange | position on the display window surface (display observer side) of a timepiece and other various measuring devices, the light reflection of these display window surfaces can be prevented, and visibility can be improved.

  Furthermore, it is placed on the inside, outside, or both sides of the windows of the cockpits (driver's cabs, wheelhouses) of vehicles such as automobiles, railway vehicles, ships, and aircraft to prevent reflection of indoor and outdoor light from the windows. Thus, it is possible to improve the visibility of the outside world of the driver (driver, driver). Furthermore, it can be arranged on the surface of a night vision device lens or window material used for crime prevention monitoring, gun sighting, astronomical observation, etc. to improve visibility at night and in the dark.

  Furthermore, the surface of the transparent substrate (window glass, etc.) that constitutes windows, doors, partitions, wall surfaces, etc. of buildings such as houses, stores, offices, schools, hospitals, etc. (inside, outside, or both sides) It is possible to improve the visibility of the outside world or the daylighting efficiency. Furthermore, it can arrange | position on the surface of a greenhouse, the transparent sheet | seat of an agricultural greenhouse, or a transparent board (window material), and can improve the sunlight lighting efficiency. Furthermore, it can arrange | position on the solar cell surface and can improve the utilization efficiency (power generation efficiency) of sunlight.

  Further, it can be widely applied to an opaque portion other than a transparent portion in order to prevent the reflection widely.

  Furthermore, in the above-described embodiment, the wavelength band of the electromagnetic wave for preventing reflection is exclusively the visible light band (all or part of the visible light band), but the present invention is not limited to this, and the electromagnetic wave for preventing reflection. May be set to a wavelength band other than visible light rays such as infrared rays and ultraviolet rays. In that case, the shortest wavelength Λmin in the wavelength band of the electromagnetic wave may be set to the shortest wavelength in which the antireflection effect in the wavelength band of infrared rays, ultraviolet rays, etc. is desired in each conditional expression. For example, when it is desired to prevent reflection in the infrared band where the shortest wavelength Λmin is 850 nm, the distance d between adjacent protrusions (or its maximum value dmax) may be designed to be 850 nm or less, for example, d (dmax) = 800 nm. . In this case, an antireflection effect cannot be expected in the visible light band (380 to 780 nm), and an antireflection article exhibiting an antireflection effect for infrared rays having a wavelength of 850 nm or more can be obtained.

  In the various exemplary embodiments described above, when the film-shaped antireflection article of the present invention is disposed on the front surface, back surface, or both front and back surfaces of a transparent substrate such as a glass plate, it is disposed and covered over the entire surface of the transparent substrate. In addition, it can be arranged only in a partial area. As an example of this, for example, for a single window glass, a film-shaped antireflection article is attached to the indoor side surface only with an adhesive in a square area at the center, and an antireflection article is provided in the other areas. The case where it does not stick can be mentioned. In the case where the antireflection article is arranged only in a partial area of the transparent substrate, it is easy to visually recognize the presence of the transparent substrate without special display or a collision prevention fence, etc. The effect of reducing the risk of collision and injury, and the effect that both the prevention of peeping indoors (indoors) and the transparency of the transparent substrate (in the region where the antireflection article is disposed) can be achieved.

DESCRIPTION OF SYMBOLS 1 Anti-reflective article 2 Base material 4 Ultraviolet curable resin layer, receiving layer 5, 5A, 5B Microprotrusion 6 Irregular surface 10 Manufacturing process 12 Die 13 Roll plate 14, 15 Roller 21 Base material 22 Uneven surface layer 23 Intermediate layer 24 Aluminum Layer 31 Support g Groove

Claims (2)

In the method for producing an antireflection article, in which microprotrusions are closely arranged, and the interval between adjacent microprotrusions is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave to prevent reflection,
A mold making process for producing a manufacturing mold for the molding process;
A shaping treatment step of producing the antireflection article by a shaping treatment using the production mold,
The mold making process includes
On the surface of the support, a process for producing an uneven surface layer for producing an uneven surface layer with a surface shape exhibiting undulation,
On the surface of the concavo-convex surface layer, a transfer support layer producing step for producing a transfer support layer,
A peeling step of peeling the transfer support layer from the uneven surface layer;
A production step of an aluminum layer for producing an aluminum layer on the surface of the transfer support layer peeled in the peeling step;
A microhole creating step of creating microholes corresponding to the microprotrusions on the surface of the aluminum layer by repetition of anodizing treatment and etching treatment,
The manufacturing method of an antireflection article provided with the arrangement | positioning process which arrange | positions the laminated body of the aluminum layer formed by producing the said fine hole, and the said support body for transcription | transfer on a base material. In the method of manufacturing a mold for manufacturing an antireflective article, in which microprotrusions are closely arranged, and the interval between adjacent microprotrusions is equal to or shorter than the shortest wavelength of the wavelength band of electromagnetic waves to prevent reflection,
On the surface of the support, a process for producing an uneven surface layer for producing an uneven surface layer with a surface shape exhibiting undulation,
On the surface of the concavo-convex surface layer, a transfer support layer producing step for producing a transfer support layer,
A peeling step of peeling the transfer support layer from the uneven surface layer;
A production step of an aluminum layer for producing an aluminum layer on the surface of the transfer support layer peeled in the peeling step;
A microhole creating step of creating microholes corresponding to the microprotrusions on the surface of the aluminum layer by repetition of anodizing treatment and etching treatment,
The manufacturing method of the metal mold | die for manufacture of an antireflective article provided with the arrangement | positioning process which arrange | positions the laminated body of the aluminum layer formed by producing the said fine hole, and the said support body for transcription | transfer on a base material.