JP2015084096A - Antireflective article, image display device, and mold for manufacturing antireflective article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflective article having a moth-eye structure, in which various characteristics for antireflection in a viewing angle direction can be set.SOLUTION: The antireflective article includes minute projections closely arranged to one another, in which a distance between adjoining minute projections is equal to or less than a shortest wavelength of a wavelength band of targeted electromagnetic waves for antireflection. In the antireflective article, multi-peak minute projections which are minute projections each having a plurality of peaks, and single-peak minute projections which are minute projections each having a single peak are mixed; and a perimeter length of the single-peak minute projection is 90% or more and 100% or less of a perimeter length of the multi-peak minute projection.

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.

  Various uses have been proposed for such antireflection articles. For example, it can be placed on the light exit surface of various image display devices to reduce external light reflection such as sunlight on the screen to improve image visibility, or to form the microprojections on a sheet or plate-like transparent substrate Furthermore, by constructing a touch panel using an electrode in which a transparent conductive film such as ITO (indium tin oxide) is formed on the microprojection group, light reflection between the touch panel electrode and various adjacent members is performed. It has been proposed to reduce the occurrence of interference fringes, ghost images, and the like.

  Patent Document 4 also provides a sufficient antireflection function for this type of antireflection article, even when a plurality of vertices are produced at the tops of the microprojections due to poor resin filling during the molding process. It describes what you can do.

  By the way, this type of anti-reflection article with a moth-eye structure has a poor appearance due to local deterioration of the anti-reflection function when other objects come into contact with the object, and white turbidity, scratches, etc. at the contact points. To do. Thereby, improvement in scratch resistance is required. However, even in the case of improving the scratch resistance, naturally, it is desired not to deteriorate the optical characteristics.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589 JP 2012-037670 A

  The present invention has been made in view of such circumstances, and an object of the present invention is to effectively avoid deterioration of optical properties and improve scratch resistance of an antireflection article having a moth-eye structure.

  The present inventor has conducted extensive research to solve the above-mentioned problems, mixed multi-peak microprojections and single-peak microprojections, and further increased the multi-peak with respect to the circumference of the single-peak microprojections. The idea of keeping the peripheral length of the conductive microprotrusions within a certain range has led to the completion of the present invention.

    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,
A multi-peak microprojection that is a microprojection having a plurality of vertices and a single-peak microprojection that is a microprojection that has one vertex are mixed,
The circumference of the monomodal microprojections is 90% or more and 100% or less of the circumference of the multimodal microprojections.

  According to (1), by forming the microprotrusions by mixing the monomodal microprotrusions and the multimodal microprotrusions, the scratch resistance is improved, and the circumference of the monomodal microprotrusions is further increased. The deterioration of the optical characteristics can be effectively avoided by being 90% or more and 100% or less of the peripheral length of the multimodal microprotrusions.

(2) In the antireflection article in which the microholes are closely arranged, and the interval between the adjacent microholes is equal to or shorter than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A microhole corresponding to a multi-peak microprojection that is a microprojection having a plurality of vertices and a microhole corresponding to a single-peak microprojection that is a microprojection that has one vertex are mixed,
The perimeter of the microhole corresponding to the monomodal microprotrusion is 90% or more and 100% or less of the perimeter of the microhole corresponding to the multimodal microprotrusion.

  According to (2), the micro-holes corresponding to the single-peak microprojections and the multi-peak micro-protrusions are mixed to improve the scratch resistance, and further, the fine corresponding to the single-peak microprojections. When the perimeter of the hole is 90% or more and 100% or less of the perimeter of the microhole corresponding to the multimodal microprotrusions, it is possible to effectively avoid the deterioration of the optical characteristics.

  (3) The antireflection article according to (1) or (2) is disposed on the panel surface of the image display panel.

  According to (3), it is possible to provide an image display device that effectively prevents deterioration of optical characteristics and prevents reflection by an antireflection article having improved scratch resistance.

(4) A mold for manufacturing an antireflective article for use in manufacturing an antireflective article,
The antireflective article is
The microprotrusions are closely placed,
The interval between the adjacent minute protrusions is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A multi-peak microprojection that is a microprojection having a plurality of vertices and a single-peak microprojection that is a microprojection that has one vertex are mixed,
The circumference of the monomodal microprojections is 90% or more and 100% or less of the circumference of the multimodal microprojections,
The mold for manufacturing the antireflection article is:
The minute holes corresponding to the minute protrusions are closely manufactured.

  According to (4), in the case of producing an antireflection article by a shaping process, it is possible to effectively avoid deterioration of optical properties in the antireflection article and improve scratch resistance.

(5) A mold for manufacturing an antireflective article for use in manufacturing an antireflective article,
The minute protrusions are closely arranged, and the interval between the adjacent minute protrusions is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A multi-peak microprojection that is a microprojection having a plurality of vertices and a single-peak microprojection that is a microprojection that has one vertex are mixed,
The circumference of the monomodal microprojections is 90% or more and 100% or less of the circumference of the multimodal microprojections.

  According to (5), the scratch resistance can be improved by mixing the single-peak microprojections and the multi-peak microprojections. In addition, since the perimeter of the single-peaked microprojections is 90% or more and 100% or less of the perimeter of the multimodal microprojections, the optical characteristics of the antireflection article produced from this mold are effectively deteriorated. Can be avoided.

  Regarding the antireflection article having the moth-eye structure, the deterioration of optical characteristics can be effectively avoided and the scratch resistance can be improved with respect to the antireflection article having the moth-eye structure.

1 is a conceptual perspective view showing an antireflection article according to a first embodiment of the present invention. 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 conceptual sectional view showing the form in which the envelope surface of the valley bottom of the microprojection exhibits an uneven surface (waviness). 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 process of the roll plate 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 detailed description of the production process of a roll plate. It is a flowchart which shows the measurement procedure of circumference. It is a figure where it uses for description of the measurement procedure of FIG. It is a chart which shows the measurement result of circumference. It is a figure which shows the measurement result of FIG. 16 with a bar graph. It is a perspective view which shows the shape of the microprotrusion of this invention. FIG. 19 is a plan view, a front view, and a side view of FIG. 18. It is a perspective view which shows the shape of the microprotrusion based on this invention different from FIG. It is the top view of FIG. 20, a front view, and a side view.

  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. Further, in the following, when simply referred to as a microprojection, both a single-peak microprojection and a multimodal microprojection are included. Moreover, each convex part which forms each vertex which concerns on a multimodal microprotrusion and a monomodal microprotrusion is called a peak suitably. In the multimodal microprotrusions, those having two vertices and three vertices are appropriately referred to as two multimodal microprotrusions and three multimodal microprotrusions, respectively.

[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 5, 5 </ b> A, 5 </ b> B on the surface of the base material 2 in the shape (form) of a transparent film. A plurality of closely arranged microprotrusions is collectively referred to as a microprotrusion group. 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 employed. Depending on the shape of such an antireflection article, the base material 2 is made of various transparent materials such as soda glass, potassium glass, lead glass, ceramics such as PLZT, quartz, meteorite, etc. An inorganic material or the like can be applied.

  The anti-reflective article 1 forms an uncured resin layer 4 (hereinafter referred to as a receiving layer as appropriate) 4 which forms a fine uneven receiving layer composed of a group of minute protrusions on a base material 2. 4 is subjected to a molding treatment and hardened, whereby the fine protrusions are placed in close contact with the surface of the substrate 2. In this embodiment, an acrylate-based ultraviolet curable resin, which is one of the molding resins used for the molding process, is applied to the receiving layer 4 to form the ultraviolet curable resin layer 4 on the substrate 2. . 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.

[Distance between adjacent protrusions]
In this way, 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. The 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 more accurate definition of “adjacent” or “adjacent” is based on the following.

  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. 2, when viewed from the normal direction of the front or back surface of the substrate, when the microprojections are not regularly arranged at a constant period, 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 (projection arrangement) of projections using an atomic force microscope (Atomic Force Microscope (hereinafter referred to as AFM)) or a scanning electron microscope (hereinafter referred to as SEM). ) Is detected. FIG. 2 is an enlarged photograph actually obtained by an atomic force microscope. Since the AFM data is accompanied by the in-plane distribution data of the height of the microprojections, this photo can be said to be a photo showing the in-plane distribution of height by luminance.

  (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. The maximum point means a point where the height is larger (maximum value) than any point around the vicinity. 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. 2 is an enlarged photograph (corresponding to the image density is high) by AFM, and FIG. 3 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. FIG. 4 is a diagram in which the Delaunay diagram (represented by white line segments) obtained from FIG. 3 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. 5 is a histogram of the frequency distribution created from the Delaunay diagram of FIG. In addition, as shown by reference numerals 5A and 5B in FIG. 2, when a concave portion such as a groove exists at the top of the protrusion, or the top is divided 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.
Here, the “peak” is a region near each vertex and is more than the groove g defined by the groove g (see FIG. 11) which is a minimum region between the vertices sharing the same flange. Say high altitude area.

  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 a microprojection (group) in plan view as shown in FIG. 2, and the distance between adjacent maximum points is selected. A value that deviates in a direction that is clearly smaller than the numerical range obtained by sampling this value (usually the value is ½ or less of the average distance between adjacent maximum points obtained by sampling) Frequency distribution is detected. In the example of FIG. 5, data having a distance between adjacent maximal points of 56 nm or less (the leftmost small mountain indicated by the arrow A) is excluded. FIG. 5 shows a frequency distribution before performing such exclusion processing. 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. 6 is a diagram showing a histogram of the frequency distribution of the protrusion height H with the protrusion root position obtained in this way 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. 6, the mean 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. 6, 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. Moreover, when all the peaks which share a collar part are the same height, let it be the height of this microprotrusion with the same height.

  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, for example, as shown in FIG. 7, when the height of the valley bottom has undulation with a period larger than the distance between adjacent projections of the microprojections, etc. ) 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. However, from the viewpoint of ensuring the antireflection function to a practically sufficient level, the average inter-protrusion distance dave may be set so that dave ≦ λmin.

2 to 6, 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. Since dave ≦ dmax, it can be seen that the condition of dave ≦ λmin 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.

〔Manufacturing process〕
FIG. 8 is a diagram illustrating a manufacturing process of the antireflection article 1. In the manufacturing process 10, in the resin supply process, an uncured and liquid ultraviolet curable resin that forms a microprojection-shaped receiving layer is applied to the base material 2 in the form of a belt-shaped film 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. The liquid acrylate-based ultraviolet curable resin is brought into close contact, and the fine concavo-convex recesses 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

  FIG. 9 is a perspective view showing the configuration of the roll plate 13. The roll plate 13 has a fine concavo-convex shape formed on the peripheral side surface of the base material, which is a cylindrical metal material, by repeating anodizing treatment and etching treatment, and the fine concavo-convex shape is formed on the substrate 2 as described above. It is shaped. For this reason, a columnar or cylindrical member in which a high-purity aluminum layer is provided at least on the peripheral side surface is used as the base material. More specifically, in this embodiment, a hollow stainless steel pipe is applied to the base material, and a high-purity aluminum layer is provided directly or via various intermediate layers. 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 microprojection group consisting of a large number of microprojections.

[Anodic oxidation treatment, etching treatment]
FIG. 10 is a diagram illustrating 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, in this step, in the aluminum layer forming step, aluminum is sputtered on the peripheral side surface of the base material to produce a high-purity aluminum layer. Subsequently, in this process, the base material is processed by alternately repeating the anodic oxidation processes A1,..., AN, and the etching processes E1,.

  In this manufacturing process, in the anodic oxidation steps 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 process E1,..., EN, the mold is immersed in an etching solution, the hole diameter of the fine hole produced and dug in the anodizing process 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.

[Improved scratch resistance]
In the antireflection article 1, the multi-peak microprojections and the single-peak microprojections are mixed to improve the scratch resistance as compared with the case where the microprojections are constituted by only the single-peak microprojections. Here, the multimodal microprotrusions not only have a plurality of vertices, but are divided into a plurality of regions by grooves formed radially outward from the center when the microprotrusions are viewed from the tip side. Each region of the plurality of regions is formed to be a peak associated with each vertex. In addition, the multimodal microprotrusions are produced by a microhole shaping process having a corresponding shape.

FIG. 11 is a cross-sectional view (FIG. 11 (a)), a perspective view (FIG. 11 (b)), and a plan view (FIG. 11 (c)) for explaining the multimodal microprotrusions having a plurality of vertices. Note that FIG. 11 is a diagram schematically showing for easy understanding, and FIG. 11A is a diagram showing a cross section by a broken line connecting the vertices of continuous minute protrusions. In FIGS. 11B and 11C, 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 four or more vertices (not shown). In these multimodal microprotrusions, a plurality of peaks share the same buttocks and are located thereon. From the point of antireflection performance, it is preferable to have a shape in which the wrinkle area perpendicular to the height direction gradually decreases toward the height direction (z direction in FIG. 11) of the multimodal microprotrusions. The shape of the unimodal microprotrusions 5 can be approximated by a round shape at the top like a paraboloid of revolution or a sharp shape at the apex like 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 shape of the multi-peak microprotrusions 5A and 5B, or the vertical cross-sectional shape when cutting along a virtual cut surface including a plurality of peaks and including the height direction (Z-axis direction in FIG. 11), has a plurality of maximum points. The shape is approximated by an algebraic curve Z = a ₂ X ² + a ₄ X ⁴ +... + A _2n X ²ⁿ +.

  The multimodal microprotrusions having a plurality of vertices are relatively thicker than the unimodal microprotrusions in the dimensions and the cross-sectional area in the vicinity of the vertices. The circumference is longer than that. Thereby, it can be said that the multimodal microprotrusions are superior in mechanical strength to the single-peak microprotrusions. As a result, when there are multi-modal microprotrusions having a plurality of vertices, it is considered that the anti-reflective article has improved scratch resistance as compared to the case of using only monomodal micro-protrusions. Furthermore, when external force is applied to the anti-reflective article specifically, compared to the case of only a single-peaked microprojection, the external force is distributed and received at more vertices, so the external force applied to each vertex is reduced. The microprotrusions can be made difficult to be damaged, thereby reducing the local deterioration of the antireflection function and further reducing the appearance defects. 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. Prevents wear and tear of small microprojections. This also reduces local deterioration of the antireflection function and further reduces the occurrence of appearance defects.

  2 to 6 described above are measurement results of the antireflection article according to the present embodiment, and in the frequency distribution shown in FIG. 5, the distance d between adjacent protrusions (value on the horizontal axis) There are two types of local maxima, short maxima of 20 nm and 40 nm and long maxima of 120 nm and 164 nm. Among these maximum values, the maximum value of the long distance corresponds to the arrangement of the microprojection bodies (the part from the middle to the heel below the top part), while the maximum value of the short distance exists in the vicinity of the top part. Corresponds to the apex (peak) of. As a result, the presence of multimodal microprotrusions can also be seen from the frequency distribution of the distance between the maximal points.

  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. Further, since the difficulty of managing the manufacturing process increases as the ratio of the multimodal microprotrusions increases, the ratio is preferably 90% or less, more preferably 80% or less. In addition, when multimodal microprotrusions are mixed, 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. The aspect ratio is defined as H / W, which is a ratio obtained by dividing the height H of the minute protrusions by the diameter W (also referred to as width or thickness) at the bottom of the valley. Here, the diameter at the bottom of the valley coincides with the diameter (at the bottom) of the column if the shape of the microprotrusion near the bottom of the valley is a column. If the shape of the vicinity of the valley bottom of the microprojection is not a cylinder and the diameter of the bottom surface obtained by crossing the virtual plane connecting the valley bottom and the microprojection differs depending on the in-plane direction, the maximum value is set to the microprojection. Of the diameter. For example, when the bottom shape of the microprojection is an ellipse, the diameter is the major axis. In addition, when the bottom surface shape of the minute protrusion is a polygon, the diameter is the maximum diagonal length. In addition, when the width of the bottom of the valley (region consisting of the minimum point of the height) is smaller than the diameter and 20% or less, the average value (H / W) ave of the aspect ratio H / W of each microprotrusion is In terms of design, it can be substantially regarded as Have / dave.

  FIG. 12 is a photograph showing a plurality of minute protrusions at the apex. FIG. 12A is obtained by AFM, and FIGS. 12B and 12C are obtained by SEM. In FIG. 12 (a), a groove g and a microprojection having three vertices, and a microprotrusion having a groove g and two vertices (two-peak multimodal microprotrusions) can be seen, and FIG. In FIG. 12 (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.

[Details of anodizing and etching]
FIG. 13 is a diagram showing in detail the anodizing process and the etching process in FIG. 12 in the case where such single-peaked microprojections and multi-peaked 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. 13, it is assumed that there is no such variation, and that the fine holes are formed by regular arrangement. FIGS. 13A to 13E are a plan view and a corresponding cross-sectional view cut out along the line aa.

  First, in this embodiment, after the first anodizing process is performed with the low applied voltage V1, the etching process (hereinafter referred to as the 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 flat surface of aluminum. 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. 13B, the applied voltage related to the second anodic oxidation treatment among the fine holes f1 produced by the first anodic oxidation 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. 13 (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. 13 (d)). 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. 13E). 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.

[Preventing deterioration of optical properties]
By the way, when multimodal microprojections and monomodal microprojections are mixed, it is naturally desirable to prevent deterioration of optical characteristics such as the reflectance in the front direction and the reflectance of oblique incident light. In this embodiment, the circumference of the multimodal microprojection is set within a certain range with respect to the circumference of the monomodal microprojection, and more specifically, the circumference of the unimodal microprojection is many. It is made 90% or more and 100% or less of the peripheral length of the ridge-shaped microprotrusions, thereby preventing the deterioration of optical characteristics sufficiently practically.

  The circumferential length is defined by the length of the valley surrounding each minute protrusion and between adjacent minute protrusions. For example, by using the two-dimensional image data provided for the above-described measurement of the distance between adjacent protrusions, the perimeter is divided into regions related to each microprojection by executing the processing procedure of FIG. Then, by dividing the region, a mesh shape is obtained by valley lines surrounding the minute projections, and can be obtained from a line segment by the mesh shape.

  That is, in the processing procedure of FIG. 14, the rearrangement process is first executed (step SP11). Here, the rearrangement process is a process of sorting the data of each pixel to be processed in descending order. In this embodiment, an x-coordinate value, a y-coordinate value, and a z-coordinate value, which are elements of a data structure representing each pixel, are set with an attribute and a maximum value flag, respectively, to obtain data for each pixel. Sort the data in descending order to create a pixel list. Here, the attribute is information indicating the classification result of each pixel, and is four states of unset, temporary placement, region boundary, and class ID. The maximum value flag is a flag used for vertex detection processing. These attributes and maximum value flags are initially set to initial values.

  Subsequently, in this process, iterative processes (SP12 to SP13) are repeatedly executed, whereby the data of each pixel registered in the pixel list is sequentially selected and classified in descending order of height. Specifically, in this iterative process, pixel data to be processed is selected, and it is determined whether or not the attribute of the pixel data is “temporary placement” (step SP14). Here, “temporary placement” refers to a case where the pixel data to be processed this time is likely to be a pixel related to a trough or a groove of a multimodal protrusion in the processing of other pixel data so far. The attribute to be set.

  Here, when the pixel to be processed is “temporary placement”, by setting the attribute of this pixel to the boundary region, the pixel is set to the boundary (which is a valley) between the minute protrusions (step SP15). Switch processing to pixel. On the other hand, if it is not “temporary placement”, whether or not a pixel having a cluster ID already set (a pixel subjected to an iterative process) exists in the neighboring 8 pixels adjacent to the pixel. Determination is made (step SP16). If there is no neighboring pixel for which the cluster ID has already been set, the pixel is set to the maximum value, the “maximum value flag” is set to true, and the attribute is set to the cluster ID of (number of already set classes + 1). Setting is made (step SP17), and the processing is switched to the next pixel. If there is already a neighboring pixel for which the cluster ID is set, it is determined whether or not the number of neighboring pixels for which the cluster ID is set (clustered neighboring pixels) is one (step SP18).

  Here, when the number of pixels is one, it is further determined whether or not there are pixels whose attributes are set to “temporary placement” in the neighboring eight pixels adjacent to the pixel (step SP19). If the set pixel does not exist, the cluster ID of the pixel for which the cluster ID is set is set in the attribute of the processing target pixel (step SP20), and thereby the minute projection of the neighboring pixel from which the processing target pixel is detected And the processing is switched to the next pixel.

  On the other hand, if the number of neighboring pixels with the cluster ID set is one and there are pixels with the attribute set to “temporary” in the adjacent eight neighboring pixels, the attribute of this pixel is set as the boundary. The region is set (step SP21), and the processing is switched to the next pixel.

  If there are two or more neighboring pixels for which a cluster ID has already been set, the attribute of this pixel is set in the boundary region (step SP22), and the attribute is set to “temporary” for the neighboring eight pixels adjacent to the pixel. Is determined (step SP23), and when there is no pixel set to “temporary placement”, the processing is switched to the next pixel.

  On the other hand, since there are two or more neighboring pixels to which the cluster ID is set, the attribute of this pixel is set to the boundary region (step SP22), and the attribute is set to “temporary” for the neighboring eight pixels adjacent to the pixel. When there is a pixel set to “place”, it is determined whether or not there are no pixels whose attributes are not set and located on the slope in the neighboring eight pixels (step SP24). In the case, the processing is switched to the next pixel. On the other hand, if such a pixel exists, temporary placement setting processing is executed (step SP25).

  In this temporary placement setting process, the normal direction of the curved surface obtained from the XYZ coordinate values of these neighboring 8 pixels is calculated from the Z coordinate values of these neighboring 8 pixels, and the normal line based on this normal direction is projected onto the XY plane. Thus, the direction of the valley is obtained from the processing target pixel. In addition, among the eight neighboring pixels, the attribute of the pixel in the direction of the valley thus obtained is set to “temporary placement”.

  With this series of processing, as shown in FIG. 15, in this embodiment, the boundary S is detected by setting the attribute sequentially with reference to the attribute setting of the adjacent eight pixels in order from the pixel having the highest height. In FIGS. 15A and 15B, (a) and (e) are views of the fine protrusions in plan view, and (b), (c) and (d) are views seen from the side. In this embodiment, by sequentially setting the attributes with reference to the attribute settings of the adjacent eight pixels in order from the pixel having the highest height, the pixel related to the vertex P1 is first set as the processing target, and the attribute is class ID = Is set to 1 (FIGS. 15A and 15B). Subsequently, as shown in FIG. 15C, the neighboring pixels of the vertex P1 are sequentially set as processing target pixels and class ID = 1 is set, and then the pixel related to the vertex P2 is set as processing target and attributed Is set to class ID = 2 (FIG. 15C). Further, the pixels of the protrusions on the vertices P1 and P2 are sequentially set as processing targets and clustered to class ID = 1 or ID = 2, respectively, and the boundary S is detected (FIG. 15 (d) and (E)). As a result, the pixels each having a z-coordinate value are classified by the cluster ID for each minute protrusion.

  Through this series of processing, valleys between adjacent minute protrusions are detected from the image data classified as the boundary S, and the peripheral length of each minute protrusion can be calculated from the image data relating to this valley.

  FIG. 16 is a chart showing circumference measurement results for the example (data 2) and the comparative example (data 1). In this chart, the unit of the perimeter is nm, and the “whole” is a measurement result of the perimeter of the multimodal microprojections and the single-peak microprojections. In addition, “2 peaks” and “3 peaks” are the measurement results for the multimodal microprotrusions of 2 peaks and the multimodal microprojections of 3 peaks, respectively, and “−” means that there is no presence. Data 2 is obtained by continuously changing the applied voltage of the anodizing treatment in the second step, the third step, and the fourth step described above with reference to FIG. 13, and in the fourth step, the application of the third step is performed. The voltage is reduced from the voltage. Compared to the case of data 2, data 1 is a variable in which the applied voltage of the anodizing treatment is greatly varied in the first to fourth steps, and in the fifth step, the voltage is reduced from the applied voltage of the fourth step. It is. FIG. 17 is a bar graph of the average measurement results of the measurement results of FIG.

  More specifically, data 2 is the case where the anodizing step and the etching step are repeated five times, and the applied voltage of the first anodizing step is V1 (a constant voltage in the range of 15V to 35V). In this case, the applied voltages in the second, third, fourth, and fifth anodic oxidation steps are 2V1, 3.5V1, 5V1, and V1, respectively. The anodizing treatment was performed for 100 seconds using an oxalic acid aqueous solution having a concentration of 0.02M. In the etching step, an etching process was performed for 45 seconds using an aqueous oxalic acid solution having a concentration of 0.02M, and then an etching process was performed for 110 seconds using an aqueous solution of phosphoric acid having a concentration of 1.0M.

Data 1 is obtained by performing the anodic oxidation process and the etching process with the same number of repetitions, solution and processing time as data 2. Data 1 shows the second, third, fourth and fifth anodes when the applied voltage in the first anodic oxidation step is V1 (a constant voltage in the range of 15V to 35V). In this example, the applied voltages in the oxidation process are 2.5 V1, 4 V1, 6 V1, and V1 ^{1/2 to} V1, respectively. In the second to fourth anodic oxidation steps, the start voltage of the second anodic oxidation treatment and the end voltage of the fourth anodic oxidation treatment are set to 2.5 V1 and 6 V1, respectively, and the applied voltage is gradually increased. Increased.

  According to FIGS. 16 and 17, it can be seen that the perimeters of all the microprojections are substantially the same in data 1 and data 2, and the perimeter increases as the number of vertices increases. Further, regarding the variance and standard deviation, it can be seen that data 1 has a larger variation than data 2. As a result of various examinations, it was found that deterioration of optical characteristics can be sufficiently prevented if the circumference of the single-peak microprojections is 90% or more and 100% or less of the circumference of the multi-peak microprojections. . Here, in data 1 and data 2, the average values of the circumferences of the single-peaked microprojections are 120.5 nm and 118.2 nm, and the average values of the circumferences of the multi-peaked microprojections are 144.3 nm and 130.3 nm. Therefore, in the data 2, the circumference of the single-peaked microprojection is 91% of the circumference of the multi-modal microprojection, which is in the range of 90% to 100%. In No. 1, the perimeter of the monomodal microprojections is 81%, and is outside the range of 90% to 100% of the perimeter of the multimodal microprojections (less than this range). As a result, it can be seen that the optical characteristics of the data 1 deteriorate.

  In addition, although the conventional antireflection article is evaluated by measurement of optical characteristics related to reflectance measurement and local observation by observation of microprojections, it is difficult to achieve a correlation between these. However, in this embodiment, it becomes possible to evaluate the optical characteristics of the antireflection article based on the local measurement result in a plan view, and various conveniences can be achieved for the examination of the antireflection article.

  According to the above configuration, the perimeter of the single-peak microprojections is 90% or more of the perimeter of the multi-peak microprojections by mixing the multi-peak microprojections and the single-peak microprojections, 100 By being less than or equal to%, it is possible to effectively avoid deterioration of optical characteristics and improve scratch resistance.

[Second Embodiment]
In this embodiment, instead of the close arrangement of the microprotrusions described above in the first embodiment, the antireflection article is produced by close placement of microholes by a shape obtained by transferring the close arrangement of the microprotrusions. For this reason, in this embodiment, the roll plate described above in the first embodiment is set as a mother roll plate, and a roll plate for mass production is produced by transferring the fine uneven shape on the peripheral side surface of the mother roll plate. An antireflection article is produced from the roll plate for mass production. Therefore, this roll plate for mass production is constituted by close arrangement of microprojections, and further comprises a mixture of monomodal microprojections and multimodal microprojections.

  In this embodiment, the antireflective article is composed of a mixture of micro holes corresponding to multimodal microprojections and microholes corresponding to monomodal microprojections. In addition, the circumference of the microhole related to the single-peak microprojection is set to be 90% or more and 100% or less of the circumference of the microhole related to the multimodal microprojection.

  In this embodiment, the scratch resistance can be improved with respect to the molding die for the production of the antireflection article by preventing the reflection by the close arrangement of the fine holes instead of the close arrangement of the fine protrusions. In addition, for the antireflection article produced from this mold, it is possible to effectively avoid the deterioration of optical characteristics.

[Specific shape of minute protrusions]
18 and 19 are a perspective view (FIG. 18), a plan view (FIG. 19 (a)), a front view (FIG. 19 (b)), and a side view showing the actual shape of the minute protrusions in the first embodiment described above. It is a figure (FIG.19 (c)). These FIG. 18 and FIG. 19 are contour maps. As described above, by switching the applied voltage in a plurality of anodic oxidation treatments, in the microprotrusions according to FIGS. 18 and 19, three peaks having greatly different heights are combined to form one microprotrusion. It can be seen that microprojections are produced by dividing the region into three peak areas by three radial grooves (swelled local minimum portions) formed outward from the center. FIG. 18 and FIG. 19 show in detail a partial selection of data based on the measurement result by AFM. The unit of the numbers in FIGS. 18 and 19 is nm. The X coordinate and the Y coordinate are coordinate values from a predetermined reference position.

  20 and 21 are diagrams showing other measurement results of the microprotrusions in the present embodiment in comparison with FIGS. 18 and 19. 20 and 21, the three peaks having substantially the same height are combined to form one minute projection, and the three peaks extend outward from the substantially central portion of the top portion. It can be seen that it is divided by three radial grooves.

  In addition, according to the results observed in this way, the inner surface of each peak in the multimodal microprotrusions is observed to have a rougher surface than the outer surface of each peak. In this way, the difference in the roughness between the inner side and the outer side of the peak can be seen from the difference from the multi-peak microprotrusions caused by the poor filling of the resin during the molding process. In these perspective views and the like, portions where no contour lines are represented are portions where data is not obtained for convenience of measurement.

[Evaluation of scratch resistance]
Table 1 shows the evaluation results of the scratch resistance. This is because the antireflection article according to the first embodiment is compared with the antireflection article having the same protrusion height distribution using only the single-peak microprotrusions. In Comparative Example 1 in the antireflection article having only single-peaked microprojections, the applied voltage of the repetitive anodizing treatment is set to the same constant voltage as that in the first step even in the second step and below. It is a comparative example produced by a height distribution similar to the height distribution, and the height distribution is due to the characteristics of so-called normal distribution. In addition, the antireflection article of Comparative Example 2 using only single-peaked microprojections was manufactured with a height distribution similar to the height distribution of Data 1 by executing the applied voltage of repeated anodizing treatment by switching between two steps. This is a comparative example, and the height distribution is due to the so-called bimodal characteristics.

  In Table 1, the column of steel wool is the result of visually confirming the change in the surface after the steel wool was pressed and reciprocated with a pressing force of 100 g and 200 g. The double circle mark was evaluated to be visually free of scratches and turbidity, and the x mark was visually observed for 6 or more scratches. The evaluation range is a rectangular area with a side of 5 cm. It can be seen that the scratch resistance is sufficiently improved by the multimodal microprotrusions.

  Further, the column of dry wiping shows 5 ° regular reflectance ΔY (%) when fingerprints are attached and then wiping in a dry state not containing a solvent is reciprocated 50 times using a nonwoven fabric. With the fingerprint attached, the 5 ° regular reflectance was set to 4%. As the nonwoven fabric, Savina Minimax (registered trademark) 150 mm □ manufactured by KB Seiren Co., Ltd. was used. In addition, the initial value of the 5 ° regular reflectance in a state where no dirt due to fingerprints was attached was 0.5%. According to the results of this study, it was found that the dirt attached by the multimodal microprotrusions was easily wiped off, and the antireflection performance was restored to a state close to that before the fingerprint attachment. In the case where it is provided, it is considered that the dirt does not penetrate deeply into the base side of the minute protrusion. This also improves the stain resistance (easy wiping property) against fingerprints.

Other Embodiment
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, the case where the anodizing treatment and the etching treatment are repeated a predetermined number of times has been described. However, the present invention is not limited to this, and can be widely applied to the case where the final treatment is anodizing treatment. .

  Further, in the above-described embodiment, the case where the antireflection article is arranged on the front side surface of various image display panels such as a liquid crystal display panel, an electroluminescent display panel, a plasma display panel, and the like is described, but the present invention is described. However, the present invention is not limited to this. For example, it can be widely applied to a case where the reflection loss of incident light from the backlight to the liquid crystal display panel is reduced by reducing the reflection loss of incident light from the backlight (increasing incident light utilization efficiency). it can. Here, the surface side of the image display panel is a light output surface of the image display panel and also a surface on the image observer side. The back side of the image display panel is the opposite side of the surface of the image display panel. In the case of a transmissive image display apparatus using a backlight (back light source), the incident light from the backlight is incident. It is also a surface.

  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 also be widely applied in the case of molding by pressing a thermoplastic resin such as a heated acrylic resin, polycarbonate resin, or polystyrene 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). In the case of the form having the microprojection groups 5, 5A, 5B,... On both surfaces of the substrate 2, the antireflection performance is larger than the form in which the microprojection group is provided only on one surface. improves. For example, when the reflectance of light at the interface between air and the substrate 2 itself is 4% and the reflectance of light at the interface between the minute protrusions and the air is 0.2%, The total reflectance of the front and back surfaces with respect to light transmitted from the front (or back) surface to the back (or front) surface of 2 is the reflectance at the interface between the layer having the fine protrusion group (receiving layer 4) and the substrate 2 Assuming that the contribution of is 0%,
(1) 8% when there are no microprojections on both sides of the substrate.
(2) 4.2% when the microprojection group is provided only on one surface of the substrate.
(3) 0.4% in the case of having microprojections on both the front and back surfaces of the substrate.
It becomes.
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, as shown in FIG. 1, the surface connecting the valley bottoms (minimum points of height) between adjacent minute protrusions is a flat surface having a constant height. Not limited to this, as shown in FIG. 7, the envelope surface connecting valleys between the microprotrusions may be wavy with a period D (that is, D> λmax) equal to or longer than the longest wavelength λmax of the visible light band. Further, the periodic undulation may have a constant height in only one direction (for example, the X direction) in the XY plane parallel to the front and back surfaces of the substrate 2 and in a direction perpendicular to the same (for example, the Y direction). Alternatively, both directions in the XY plane (X direction and Y direction) may have undulations. The uneven surface 6 that undulates with a period D satisfying D> λmax is superimposed on a microprojection group composed of a large number of microprojections, so that the reflected light remaining without being completely prevented from being reflected by the microprojection group is scattered, so that Reflected light, particularly specularly reflected light, can be made more difficult to visually recognize, and the antireflection effect can be further improved.

In addition, when the period D of the uneven surface 6 is not constant over the entire surface and has a distribution, the frequency distribution of the distance between the protrusions is obtained for the uneven surface, and the average value is D _AVG and the standard deviation is Σ. When
D _MIN = D _AVG -2Σ
Designed as an alternative to period D with a minimum inter-protrusion distance defined as That is, conditions that can sufficiently exhibit the scattering effect of the reflected light of the microprojections are as follows:
D _MIN > λmax
Also, the Rz value (10-point average roughness) defined in JIS B0601 (1994) corresponding to the height difference of the unevenness is
Rz ≧ λmin
It is. Usually, D or D _MIN is 1 to 600 μm, preferably 10 to 300 μm. Usually, Rz is set to 0.4 to 5 μm.
An example of a specific manufacturing method for forming a concavo-convex microprojection group having an uneven surface 6 in which the envelope surface connecting the valley bottoms of each microprojection is D (or D _MIN )> λmax is as follows. is there. That is, in the manufacturing process of the roll plate 13, a concavo-convex shape corresponding to the concavo-convex shape of the concavo-convex surface 6 is formed on the surface of a cylindrical (or columnar) base material by sandblasting or mat (matte) plating. Next, an appropriate intermediate layer is formed directly or if necessary on the uneven surface, and then an aluminum layer is laminated. Thereafter, an aluminum layer formed with a surface shape corresponding to the uneven surface is subjected to anodizing treatment and etching treatment in the same manner as in the above embodiment to form a microprojection group including microprojections 5, 5A, 5B. To do.

  In the above-described embodiment, the case where the mold for the shaping process is manufactured by repeating the anodizing process and the etching process has been described. However, the present invention is not limited to this, and the photolithography technique is applied. The present invention can also be widely applied to molds for mold processing.

  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 the antireflection article with the film shape is arranged on the front side surface of the image display panel or the incident surface of the illumination light has been described. However, the present invention is not limited to this and is applied to various applications. be able to. 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 this case, it is possible to prevent interference fringes such as Newton rings due to light interference between the image display panel and the surface side member, and between the light emission surface of the image display panel and the light incident surface side of the surface side member. Thus, it is possible to prevent ghost images due to multiple reflections, and to achieve effects such as reduction of reflection loss with respect to image light emitted from the screen and entering these surface side members.

  Alternatively, a transparent electrode constituting the touch panel is formed on a film or plate-like transparent substrate with a group of microprojections specific to the present invention, and a transparent conductive film such as ITO (indium tin oxide) is further formed on the group of microprojections. The formed one can be used. In this case, it is possible to prevent light reflection between the touch panel electrode and the counter electrode or various members adjacent to the touch panel electrode, thereby reducing the occurrence of interference fringes, ghost images, and the like.

  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 incandescent bulbs, light emitting diodes, fluorescent lamps, mercury lamps, EL (electroluminescence), etc. (in some cases, it also serves as a diffuser plate, condenser lens, optical filter, 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 stores products or exhibits used in various stores, museums, museums, etc., and arranges them on the front, back, or both sides of the transparent window (or door) of various display boxes or showcases to be displayed, It is possible to improve the visibility of products to be displayed or exhibits. 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.

  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 Minute protrusion 6 Uneven surface 10 Manufacturing process 12 Die 13 Roll plate 14, 15 Roller g Groove

Claims (5)

In the antireflection article in which the microprotrusions are closely arranged and the interval between the adjacent microprotrusions is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave to prevent reflection,
A multi-peak microprojection that is a microprojection having a plurality of vertices and a single-peak microprojection that is a microprojection that has one vertex are mixed,
An antireflective article in which the perimeter of the single-peak microprojections is 90% or more and 100% or less of the perimeter of the multimodal microprojections. In the antireflection article in which the minute holes are closely arranged and the interval between the adjacent minute holes is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A microhole corresponding to a multi-peak microprojection that is a microprojection having a plurality of vertices and a microhole corresponding to a single-peak microprojection that is a microprojection that has one vertex are mixed,
The antireflection article, wherein the perimeter of the microhole corresponding to the monomodal microprojection is 90% or more and 100% or less of the perimeter of the microhole corresponding to the multimodal microprotrusion. The image display apparatus which has arrange | positioned the antireflection article | item of Claim 1 or Claim 2 on the panel surface of an image display panel. A mold for manufacturing an antireflective article for use in manufacturing an antireflective article,
The antireflective article is
The microprotrusions are closely placed,
The interval between the adjacent minute protrusions is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A multi-peak microprojection that is a microprojection having a plurality of vertices and a single-peak microprojection that is a microprojection that has one vertex are mixed,
The circumference of the monomodal microprojections is 90% or more and 100% or less of the circumference of the multimodal microprojections,
The mold for manufacturing the antireflection article is:
A mold for manufacturing an antireflective article, in which fine holes corresponding to the fine protrusions are in close contact with each other. A mold for manufacturing an antireflective article for use in manufacturing an antireflective article,
The minute protrusions are closely arranged, and the interval between the adjacent minute protrusions is equal to or less than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
A multi-peak microprojection that is a microprojection having a plurality of vertices and a single-peak microprojection that is a microprojection that has one vertex are mixed,
A mold for manufacturing an antireflective article, wherein the circumference of a single-peak microprojection is 90% or more and 100% or less of the circumference of a multimodal microprojection.