JP2014153684A - Manufacturing method of antireflection article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an antireflection article related to a moth-eye structure capable of removing stains such as fingerprints.SOLUTION: In a manufacturing method of an antireflection article, fine projections 5, 5A, 5B are densely arranged on an antireflection article 1, and an interval between neighboring fine projections 5, 5A, 5B is equal to or narrower than a minimum wavelength of an electromagnetic wave being an antireflection target. On a resin surface related to the fine projections 5, 5A, 5B, a layer of a fluorine-based lubricant including a perfluoroalkyl polyether is formed, and thereafter, exposed to ionization radiation so that a lubricant layer 3 is formed.

Description

  The present invention relates to a method of manufacturing an antireflection article for preventing reflection by closely arranging a large number of minute protrusions at intervals of not more than the shortest wavelength in the wavelength band of electromagnetic waves for preventing reflection.

  In recent years, regarding antireflection articles that are film-shaped antireflection articles, a method has been proposed in which a large number of microprotrusions are placed in close contact with 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 interval 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. . 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.

  Patent Documents 4 and 5 disclose a method of antifouling coating relating to a translucent material.

  By the way, the anti-reflection article with the moth-eye structure has high anti-reflection performance, but due to its surface structure, dirt such as sebum is likely to adhere, and the attached dirt penetrates deep into the groove between the microprojections. Therefore, there is a problem that it is difficult to remove dirt such as fingerprints. In the antireflective article, such dirt deteriorates the surface appearance.

  Although it is conceivable to apply the method disclosed in Patent Documents 4 and 5 as a method for solving this problem, that is, a water-repellent surface treatment with a fluorine-containing organic compound, there is still a problem that is still insufficient in practice.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589 JP 2010-201799 A JP 2012-037896 A

  The present invention has been made in view of such a situation, and an object thereof is to make it possible to easily remove stains such as fingerprints on an antireflection article having a moth-eye structure.

  The present inventor has intensively studied to solve the above-mentioned problems, and has arrived at the idea of irradiating with ionizing radiation after laminating a fluorine-based lubricant on the resin surface related to the microprojections, thereby completing the present invention. It came to.

  In the following, a microprojection having a plurality of vertices is referred to as a multi-peak microprojection, and a microprojection having only one vertex is referred to as a single-peak microprojection by contrast with the multi-peak microprojection. . Moreover, each convex part which forms each vertex which concerns on a multimodal microprotrusion and a monomodal microprotrusion is called a peak suitably.

Specifically, the present invention provides the following: (1) Reflection in which minute protrusions are closely arranged and the interval between adjacent minute protrusions is equal to or shorter than the shortest wavelength of an electromagnetic wave for preventing reflection A method of manufacturing a prevention article,
A method for producing an antireflective article, comprising: forming a lubricating layer of a fluorine-based lubricant containing perfluoroalkyl polyether on a resin surface constituting the microprojections, and then irradiating with ionizing radiation.

(2) The method for producing an antireflective article according to claim 1, wherein the perfluoroalkyl polyether has the following general formula.
[Chemical 1]
F- [CF (CF ₃ ) CF ₂ O] _n —CF ₂ (CF ₃ )
(N represents an integer of 7 to 60.)

  (3) The method for producing an antireflective article according to claim 1 or 2, wherein the ionizing radiation is an electron beam having an irradiation intensity of 30 kGy to 120 kGy.

(4) The method for producing an antireflective article according to any one of (1) to (3), wherein the fluorine-based lubricant has a viscosity at 40 ° C. of 1 mm ² / S or more and 1000 mm ² / S or less.

  (5) The method for producing an antireflective article according to any one of (1) to (4), wherein the resin constituting the microprojections is a cured product of a (meth) acrylate compound.

(6) At least a part of the microprojections is
Any one of (1) to (5), which is a multi-peak microprojection having a plurality of vertices and created by a shape in which the top is divided into ridges related to each vertex by a radial groove formed at the top A method for producing an antireflection article as described in 1.

  (7) An image display device in which an antireflection article obtained by the manufacturing method according to any one of (1) to (6) is disposed on a light exit surface of an image display panel.

  With respect to the antireflection article according to the moth-eye structure, dirt such as fingerprints can be easily removed.

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 figure where it uses for description of a microprotrusion. It is a figure which shows the manufacturing process of the antireflection article | item of FIG. It is a figure which shows the structure of a fluorine-type lubricant. It is a figure which shows a shaping process. It is a figure which shows the roll plate which concerns on the reflection preventing article of FIG. It is a figure which shows the preparation processes of the roll plate of FIG.

[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 apparatus according to this embodiment, the antireflection article 1 is held by being attached to the front side surface of the image display panel, and the reflection of external light such as sunlight and electric light on the screen is reduced by the antireflection article 1. And improve visibility. The antireflection article is not limited to a flat film shape, but may be a flat sheet shape or a flat plate shape (referred to as a film, a sheet, or a plate in order of relatively small thickness). In addition, instead of a flat shape, a curved shape, a three-dimensional film shape, a sheet shape, or a plate shape can be used, and various lenses, prisms, and other three-dimensional shapes are appropriately used depending on the application. Can be adopted.

  Here, the antireflection article 1 is produced by closely arranging a large number of minute protrusions on the surface of the substrate 2 made of a transparent film. A plurality of closely arranged microprotrusions is collectively referred to as a microprotrusion group. In this embodiment, the antireflection article 1 is further provided with a lubricating layer 3 on the surface (side surface of the minute protrusion).

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

  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, a (meth) acrylate-based ultraviolet curable resin that is one of the molding resins used for the molding process is applied to the receiving layer 4, and the ultraviolet curable resin layer 4 is formed on the substrate 2. Is formed. The antireflective article 1 is produced by tapering each microprotrusion so that the refractive index gradually changes in the thickness direction due to the uneven shape due to the microprotrusion, thereby reflecting incident light in a wide wavelength range by the principle of the moth-eye structure. Reduce.

  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 projections are closely arranged so that when a line segment is created so as to sequentially follow the valleys between the minute projections, a large number of polygonal regions surrounding each minute projection 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 resin composition constituting the ultraviolet curable resin, which is a resin constituting the microprojections in the present invention, has at least one functional group such as a vinyl group, a carboxyl group, a hydroxyl group, and the like and is derived from a photopolymerization initiator. It has monomers and oligomers that are cured by radical polymerization with radicals.

  Examples of such monomers and oligomers include acrylic types such as epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, and silicon acrylate, and non-acrylic types such as unsaturated polyester / styrene and polyene / styrene. Of these, (meth) acrylate is preferred from the viewpoint of curing speed and wide selection of physical properties.

  As monofunctional (meth) acrylates, 2-ethylhexyl acrylate, 2-ethylhexyl EO adduct acrylate, ethoxydiethylene glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate caprolactone adduct, 2 -Phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, nonylphenol EO adduct acrylate, acrylate obtained by adding caprolactone to nonylphenol EO adduct, 2-hydroxy-3-phenoxypropyl acrylate, tetrahydrofurfuryl acrylate, caprolactone adduct acrylate of furfuryl alcohol, acryloyl Morpholine, dicyclopentenyl acrylate, disi Lopentanyl acrylate, dicyclopentenyloxyethyl acrylate, isobornyl acrylate, 4,4-dimethyl-1,3-dioxolane caprolactone adduct, 3-methyl-5,5-dimethyl-1,3-dioxolane An acrylate of a caprolactone adduct of

  Multifunctional (meth) acrylates include hexanediol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, hydroxypivalic acid neopentyl glycol ester diacrylate, hydroxypivalic acid neopentyl glycol ester Caprolactone adduct diacrylate, acrylic acid adduct of 1,6-hexanediol diglycidyl ether, diacrylate of hydroxypivalaldehyde and trimethylolpropane acetal compound, 2,2-bis [4- (acryloyloxy) Diethoxy) phenyl] propane, 2,2-bis [4- (acryloyloxydiethoxy) phenyl] methane, hydrogenated bisphenol ethylene oxide addition Diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane propylene oxide adduct triacrylate, glycerin propylene oxide adduct triacrylate, dipentaerythritol hexaacrylate pentaacrylate mixture , Caprolactone adduct acrylate of dipentaerythritol, tris (acryloyloxyethyl) isocyanurate, 2-acryloyloxyethyl maleate and the like.

  As a polymerization initiator contained in the ultraviolet curable resin composition, a polymerization initiator used during polymerization of a general ultraviolet curable resin composition can be used.

  Specifically, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methyl Acetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy- 2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropyl Pyrthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2 , 6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, ethyl-2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, and the like.

  Commercially available polymerization initiators include, for example, Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI 11850, CG 24-61, Darocurl 116, 1173 (above, Ciba Specialty Chemicals Co., Ltd.) For example, Lucirin LR8728, 8893X (manufactured by BASF), Ubekrill P36 (manufactured by UCB), KIP150 (manufactured by Lamberti) and the like can be used.

  The blending amount of the polymerization initiator is preferably in the range of 0.01% by weight to 10% by weight in the total composition, and particularly preferably in the range of 0.5% by weight to 7% by weight. .

[Details of distance between adjacent protrusions]
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 an antireflection effect for all wavelengths in the visible light band is d ≦ 300 nm, and a more preferable condition is d ≦ 200 nm. 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 of projections (planar shape of projection arrangement) is detected using an atomic force microscope (AFM) or a scanning electron microscope (SEM). FIG. 2 is an enlarged photograph actually obtained by an atomic force microscope.

  (2) Subsequently, the maximum point of the height of each protrusion (hereinafter simply referred to as the maximum point) is detected from the obtained in-plane arrangement. There are various methods for obtaining the maximum point, such as a method of sequentially comparing the planar view shape and the enlarged photograph of the corresponding cross-sectional shape to obtain the maximum point, and a method of obtaining the maximum point by image processing of the plan view enlarged photo. Can be applied. FIG. 3 is a diagram showing the detection result of the maximum point by the processing of the image data relating to the enlarged photograph shown in FIG. 2, and the portions indicated by black dots in this figure are the maximum points of the respective protrusions. 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 with 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. As shown in FIG. 2 and FIG. 7, 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, the distribution of such protrusion is determined 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 and a fine structure in which the top is split into a plurality of peaks, and selecting only the data of the projection body itself.

  Specifically, in a fine structure in which a concave portion exists at the top of the protrusion, or a fine structure related to a multi-modal micro protrusion in which the top is divided into a plurality of peaks, a single peak that does not have such a fine structure. The distance between adjacent local maximum points is clearly different from the numerical value range in the case of a sexual microprojection. 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. The value of is sampled and the value clearly deviates from the numerical range obtained by sampling (usually data whose value is ½ or less of the average distance between adjacent maximum points obtained by sampling) To detect the frequency distribution. In the example of FIG. 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 projection height H shown in FIG. 6, in the case of a multi-peak microprojection, the plurality of data are mixed for one projection because it has a plurality of vertices. Therefore, in this case, the frequency distribution is obtained by adopting the vertex having the highest height from among the plurality of vertices belonging to the same microprotrusion as the protuberance.

  In addition, the reference position when measuring the height of the protrusion described above is based on the valley bottom (minimum point of height) between the adjacent minute protrusions as a reference of height 0. However, when the height of the valley bottom itself varies depending on the location (for example, when the height of the valley bottom has undulation with a period larger than the distance between adjacent projections of the microprojections), (1) First, the base material 2 The average value of the height of each valley bottom measured from the front surface or the back surface is calculated in an area sufficient for the average value to be collected. (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.

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. 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. From the observation results by AFM and SEM, and the analysis result of the height distribution of the microprojections, the multi-peak microprojections tend to occur more frequently with the microprojections with a higher height than the microprojections with a relatively low height. It turned out to be.

[Details of microprotrusions]
By the way, when the production conditions were changed in various ways and the antireflection article was examined in detail, the single antireflection article having a single apex such as a polygonal pyramid shape and a rotating paraboloid shape like this conventional antireflection article. When only ridge-shaped microprojections are made and the height of each apex is made uniform, for example, when another object touches, the shape of the microprojections is uniformly damaged over a wide range. As a result, it was found that the antireflection function locally deteriorated, and that the appearance was poor due to the occurrence of white turbidity, scratches, etc. However, it has been found that changing the manufacturing conditions improves such scratch resistance.

  When the surface shape of such an antireflection article with improved scratch resistance was observed with an AFM (Atomic Force Microscope) and SEM (Scanning Electron Microscope), a large number of microprojections were observed. It was found that there are multimodal microprojections having a plurality of vertices. A multi-peak microprotrusion is a protrusion that is created by a shape in which a top portion is divided into ridges associated with each vertex by a radial groove formed at the top portion, and is created from a microhole having a corresponding shape. Although various types of microscopes are provided here for observing the fine shape, AFM and SEM are suitable for observing the surface shape of the antireflection article without damaging the fine structure. Yes.

FIG. 7 is a diagram for explaining the multimodal microprotrusions having a plurality of vertices. FIG. 7 (a)) is a diagram showing a section taken along a polygonal line connecting the vertices of continuous microprotrusions. FIGS. 7 (b) and 7 (c) are perspective views of multi-peak microprotrusions and It is a top view. FIG. 7 is a diagram schematically showing for easy understanding. 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. 7)) as they move away from the base material 2 toward the top. 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 were those having four or more vertices (not shown). The shape of the unimodal microprotrusions 5 can be approximated by a round shape at the top, such as a paraboloid of revolution, or a pointed shape, such as a cone. On the other hand, the shape of the multimodal microprotrusions 5A and 5B is roughly approximated by a shape in which a groove-shaped recess is cut in the vicinity of the top of the monomodal microprotrusion 5 and the top is divided into a plurality of peaks. The The shape of the multi-peaked microprotrusions 5A, 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. 7) is the maximum point. It is a shape that is approximated by an algebraic curve Z = a ₂ X ² + a ₄ X ⁴ +... + A _2n X ²ⁿ +.

In such multi-peak microprojections having a plurality of vertices, the thickness of the skirt portion relative to the size in the vicinity of the vertices is relatively thicker than that of a single-peak microprojection. Thereby, it can be said that the multimodal microprotrusions are superior in mechanical strength to the single-peak microprotrusions. Thus, when there are multi-peaked microprojections having a plurality of vertices, it is considered that the anti-reflective article has improved scratch resistance as compared with the case of using only single-peak microprojections. In addition, when an external force is applied to the anti-reflective article, the external force is distributed and received at more vertices than when only a single-peaked microprojection is used. Thus, it is possible to make the microprotrusions less likely to be damaged, thereby reducing 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. Furthermore, many of the multimodal microprojections, highest peak height (foot height of the highest peaks belonging to the same microprojections) is to produce the average value H _AVG or more microprojections of the projection height, the external force First, each peak portion is received and sacrificially damaged, thereby preventing wear of the main body portion lower than the peak of the microprojection and the microprojection having a height lower than that of the multimodal microprojection. 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 multi-peaked microprotrusions can be seen also from the frequency distribution of the distance between the maximal points.

  Needless to say, the multi-peak microprotrusions can improve the scratch resistance due to their presence, but if they do not exist sufficiently, the effect of improving the scratch resistance cannot be fully exhibited. From such a viewpoint, in the present invention, the ratio of the number of multimodal microprojections in all the microprojections present on the surface is set to 10% or more. In particular, in order to sufficiently exhibit the effect of improving the scratch resistance due to the multimodal microprojections, the ratio of the multimodal microprojections is 30% or more, preferably 50% or more.

  Further, when the antireflection article having such a microprojection group (5, 5A, 5B,...) Including the multimodal microprotrusions 5A and 5B is examined in detail, the heights of the microprojections are variously different. (See FIGS. 6 and 7 (a)). Here, as described above, the height of each microprotrusion is the height of the peak (highest peak) having the highest height at the top of a specific microprotrusion that shares the ridge (root). say. In the case of a single-peak microprojection such as the microprojection 5 in FIG. 7A, the height of the only peak (maximum point) at the top is the projection height of the microprojection. In addition, in the case of a multimodal microprotrusion such as the microprotrusions 5A and 5B in FIG. 7A, the height of the microprotrusions has the highest peak height among a plurality of ridges sharing a ridge at the top. The height. In this way, when the heights of the microprojections are variously different, for example, even when the shape of the microprojections having a high height is damaged by contact with an object, the shape is maintained in the microprojections having a low height. It will be. Also in this case, in the antireflection article, local deterioration of the antireflection function can be reduced, and furthermore, occurrence of defective appearance can be reduced, and as a result, scratch resistance can be improved.

  Further, when dust adheres between the microprojection group on the surface of the antireflection article and the object, when the article slides relative to the antireflection article, the dust functions as an abrasive to form microprojections ( Group) wear and damage are promoted. In this case, if there is a difference in height between the microprojections constituting the microprojection group, the dust strongly contacts the microprojections having a high height and is damaged. On the other hand, the contact with the low-height microprotrusions is weakened, and damage to the low-height microprotrusions is reduced, and the antireflection performance is maintained by the low-height microprotrusions that remain intact or light.

  In addition to this, the microprotrusion group with distribution (height difference) in the height of each microprotrusion has a broad antireflection performance and has light with multiple wavelengths such as white light or a broadband spectrum. For light, it is advantageous to realize a low reflectance in the entire spectral band. This is because the wavelength band in which good antireflection performance can be exhibited by such a microprojection group depends not only on the distance d between adjacent projections but also on the projection height.

  Further, in this case, only the high microprojections out of the many microprojections come into contact with various member surfaces arranged to face the antireflection article 1, for example. Thereby, it is possible to remarkably improve the slip as compared with the case where only the minute protrusions having the same height are used, and it is possible to easily handle the antireflection article in the manufacturing process or the like. From the viewpoint of improving the slip as described above, the variation needs to be 10 nm or more when defined by the standard deviation. However, when the variation is larger than 50 nm, the surface becomes rough. Therefore, the height variation is preferably 10 nm or more and 50 nm or less.

  In addition, when multi-peaked microprojections coexist in this way, the antireflection performance can be improved as compared with the case of using only single-peaked microprojections. That is, the multi-peak microprotrusions 5A, 5B, etc. as shown in FIG. 2, FIG. 7 and the like are unimodal even when the distance between adjacent protrusions is the same or when the protrusion height is the same. Compared with the microprotrusions, the light reflectance is further reduced. The reason for this is that the multi-modal microprotrusions 5A, 5B, etc. have a higher rate of change in the effective refractive index in the vicinity of the apex than the monomodal microprotrusions below the apex (in the middle and the heel). This is because becomes smaller.

That is, in FIG. 7, assuming that z = 0 is the height H = 0, and it is assumed that the microprojections 5, 5A, etc. are cut at a virtual cutting plane Z = z orthogonal to the height direction (Z-axis direction). The effective refractive index n _ef obtained as an average value of the refractive indexes of the microprojections on the surface Z = z and the surrounding medium (usually air) is the refraction of the surrounding medium (here, air) on the cut surface Z = z. The refractive index of the constituent material of n _A = 1, the minute protrusions 5, 5A,... Is n _M > 1, and the total value of the sectional area of the peripheral medium (air) is S _A (z). When the total value of the cross-sectional areas of 5A,... Is S _M (z),
n _ef (z) = 1 × S _A (z) / (S _A (z) + S _M (z)) + n _A × S _M (z) / (S _A (z) + S _M (z)) (Formula 1 )
It is represented by This is because the refractive index n _A of the peripheral medium and the refractive index n _M of the constituent material of the microprojections are respectively expressed as a total sectional area S _A (z) of the peripheral medium and a total value S _M (z) of the total sectional area of the microprojections. Proportionally distributed value.

Here, when considering the single-peaked microprojections 5 as a reference, the multi-peak microprojections 5A, 5B,... Therefore, in the virtual cutting plane Z = z that cuts the vicinity of the top, the multimodal microprotrusions 5A, 5B,... Have a relatively low refractive index compared to the single-peak microprotrusions 5,. The ratio of the total cross-sectional area S _A (z) of a certain peripheral medium is further increased as compared with the ratio of the total cross-sectional area S _M (z) of the microprojections having a relatively high refractive index.

As a result, the effective refractive index n _ef (z) at the virtual cut surface Z = z is larger than that of the multimodal microprotrusions 5A, 5B,. It becomes closer to the refractive index n _A of the peripheral medium. The difference between the refractive index of the effective refractive index and the surrounding medium multimodal microprotrusions in the plane _{Z = z | n ef (z} ) -n A (z) | multi, the effective refractive index of the unimodal microprojection the difference between the refractive index of the surrounding medium and _{| n ef (z) -n a} (z) | When _mono,
| N _ef (z) −n _A (z) | _multi <| n _ef (z) −n _A (z) | _mono (Expression 2)
It becomes. Here, if n _A (z) = 1,
| N _ef (z) -1 | _multi <| n _ef (z) -1 | _mono (Formula 2A)
It becomes.

  As a result, the effective refractive index of the microprojection group including the multi-peak microprojections (including the peripheral medium between the microprojections) in the vicinity of the top portion is higher than that of the single-peak microprojection group. And, more specifically, the rate of change of the refractive index per unit distance in the height direction of the microprojections is further reduced, in other words, the refractive index is high. It can be seen that it is possible to further increase the continuity of the change in direction.

In general, when light is incident on an interface between an adjacent medium having a refractive index n _{0 and} a medium having a refractive index n ₁ , the reflectance R of the light at the interface is set as an incident angle = 0.
R = (n ₁ −n ₀ ) ² / (n ₁ + n ₀ ) ² (Formula 3)
It becomes. From this equation, the smaller the refractive index difference n ₁ -n ₀ between the media on both sides of the interface, the lower the light reflectivity R at the interface, and as (n ₁ -n ₀ ) approaches 0, R also approaches 0. It will be.

  From (Expression 2), (Expression 2A), and (Expression 3), the microprotrusion group (including the peripheral medium between the microprotrusions) including the multimodal microprotrusions 5A, 5B,. The light reflectance is reduced as compared with the projection group consisting of only the minute projections 5.

  Even if a microprojection group consisting of only single-peak microprojections 5 is used, by setting the maximum value dmax of the distance between adjacent projections to a sufficiently small value not more than the shortest wavelength λmin of the wavelength band of the electromagnetic wave for preventing reflection, It is possible to exhibit a sufficient antireflection effect. However, in this case, since the distance between adjacent peaks and the distance between adjacent minute protrusions are the same, a phenomenon (so-called sticking) in which adjacent minute protrusions are brought into contact with each other and integrated together is likely to occur. When sticking occurs, the substantial distance d between adjacent protrusions increases by the number of minute protrusions integrated together.

  For example, when four microprojections with d = 200 nm are stuck, the size of the stuck and integrated projection is substantially d = 4 × 200 nm = 800 nm> the longest wavelength in the visible light band (780 nm). The antireflection effect is locally impaired.

On the other hand, in the case of a microprojection group consisting of multimodal microprotrusions 5A, 5B,..., The distance between adjacent protuberances d ^PEAK between the peaks in the vicinity of the apex is between the adjacent protuberances of the microprotrusion main body from the heel to the middle It is smaller than the distance d _BASE (d ^PEAK <d _BASE ), and is usually about d ^PEAK = d _BASE / 4 to d _BASE / 2. Therefore, sufficient antireflection performance can be obtained by setting the distance d ^PEAK << λmin between adjacent protrusions between the peaks. However, each peak of the multi-peak microprojection has a small ratio of the height of the peak to the width of the ridge, and 1 / of the ratio of the height of the apex to the width of the ridge of the single-peak microprojection. It is about 2 to 1/10. Therefore, for the same external force, the peak of the multimodal microprotrusions is less likely to deform than the single-peak microprotrusions. In addition, the main body itself of the multimodal microprotrusions has a greater distance between adjacent protrusions and a greater strength than the ridges. Therefore, after all, the microprojection group composed of multimodal microprotrusions can easily achieve both the difficulty of sticking and the low reflectance as compared with the projection group composed of monomodal microprotrusions.

  In addition, even if it is other uses for antireflection of visible light, or under a visible light environment, the antireflection material depends on the assumed antireflection wavelength depending on the environmental conditions where the antireflection material is installed and used. By forming a moth-eye structure and having a height distribution, as mentioned above, even when materials with lower hardness due to process requirements are used, they prevent sticking to each other. In addition, it is possible to produce an antireflection material having both optically required performance. For example, when it is desired to obtain antireflection performance in the ultraviolet region around 380 nm, the moth-eye height can be about 50 μm. Similarly, the infrared region around 700 nm is about 150 μm to 400 μm in consideration of practical use. Is possible. As described above, it is possible to find manufacturing conditions that saturate the height of the arrangement pitch of the moth-eye, and to effectively control the reflectance of the moth-eye. In addition, the top structure of the moth-eye can be improved from the conventional single peak to achieve both height and reflectivity, and it is difficult to cause physical sticking and can effectively reduce reflectivity. Yes.

(Lubricating layer)
As shown to Fig.7 (a), the antireflection article 1 is provided with the lubricating layer 3 which irradiates the ionizing radiation after forming a fluorine-type lubricant on the resin surface which concerns on the microprotrusion 5. FIG. Here, the lubricating layer 3 is a fluorine-based lubricant containing perfluoroalkyl polyether.

  As the fluorine-based lubricant, in the present invention, a fluorine-based lubricant containing perfluoroalkyl polyether is used. The perfluoroalkyl polyether is a fluorine compound having a perfluoroalkyl polyether represented by the following general formula as a molecular skeleton, for example.

[Chemical 1]
Rf ^A- (Rf ^N -O-) _n -Rf ^Z
(Rf ^A represents a hydrogen atom, a fluorine atom and an alkyl group which may be substituted with a fluorine atom, and Rf ^N and Rf ^Z represent an alkylene group which may be partially or entirely substituted with a fluorine atom. ^N may be the same or different, and n represents an integer of 1 or more, and when n is 2 or more, a plurality of Rf ^N may be the same or different, but of Rf ^A , Rf ^N , and Rf ^Z At least one of which has a fluorine substituent.)

  Specifically, for example, poly (hexafluoropropylene oxide) such as Krytox (registered trademark) 100 to 107 manufactured by DuPont represented by the general formula of FIG. 9 is preferable. The base oil is a low molecular weight hexafluoropropylene epoxide shown in FIG. 9, and this base oil is a homopolymonomer whose ends are blocked with fluorine.

As the fluorine-based lubricant, a fluorine-based liquid lubricant (oil) is preferably applied, and the viscosity of the fluorine-based lubricant at 40 ° C. is preferably 1 mm ² / S or more and 1000 mm ² / S or less.

The lubricating layer is applied to the entire surface, and is thin enough to prevent the irregular shape on the surface of the antireflective article 1 related to the fine protrusions from being impaired, for example, 0.5 to 10 g / m in application amount. ^{2 is} created.

  In the present invention, the lubricating layer 3 is finally formed by irradiating the lubricating layer with ionizing radiation. This will be described in the manufacturing method described later.

  Thus, in this embodiment, the surface of the fine protrusion is coated with a fluorine-based lubricant, and further irradiated with ionizing radiation, the surface of the fine protrusion can be an ultra-low friction surface, without impairing the antireflection performance, It becomes possible to wipe off dirt by dry wiping. Further, among the dirts related to this type of antireflection article, even the most difficult fingerprints can be wiped off by dry wiping.

  That is, the lubricating layer 3 of the present invention can ensure sufficient water repellency and ensure slipperiness (lubricity). As a result, dirt on fingerprints attached to the surface can be easily removed from the surface by dry wiping. In addition, the peeled-off dirt can be quickly removed without falling into the valleys between the protrusions, so that even fingerprints can be easily removed by dry wiping.

〔Manufacturing process〕
FIG. 8 is a diagram illustrating a manufacturing process of the antireflection article 1. In this manufacturing process, a mold for forming process is prepared in the mold creating process (step SP2). Further, in the molding process (step SP3), the fine protrusions 5 are created on the base material 2 by the molding process using this mold. Further, subsequently, in the lubricating layer creating step (step SP4), a lubricating layer is formed, and thereafter the ionizing radiation irradiation step (step SP5) is performed to finally form the lubricating layer 3. In this manufacturing process, an adhesive layer, a separator film, and the like for further placement on the image display panel are provided, and an antireflection article is produced by cutting into a desired size.

  FIG. 10 is a diagram illustrating a manufacturing process of the antireflection article 1 according to Step SP3. 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

[Molding mold]
FIG. 11 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 large number of fine protrusions. At that time, by appropriately adjusting various conditions such as the purity (impurity amount), crystal grain size, anodizing treatment and / or etching treatment of the aluminum layer, the shape of the fine protrusion unique to the present invention is obtained.

[Anodic oxidation treatment, etching treatment]
FIG. 12 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, 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 acid solutions can be used. More specifically, for example, a sulfuric acid aqueous solution, an oxalic acid aqueous solution, a 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.

  In this embodiment, by repeating the anodic oxidation process and the etching process in this way, the micro hole is dug while expanding the hole diameter, and thereby the micro hole for forming the minute projection is produced. Multi-modal microprotrusions are created by microholes having a concave shape corresponding to the top of the structure, and such microholes are etched very closely. It is produced integrally by processing. This makes it possible to mix multi-peak microprojections and single-peak microprotrusions by greatly varying the distance between the microholes produced by anodization, and variations in anodization treatment. This can be realized by increasing.

  In addition, the variation in the height of the fine hole is due to the variation in the depth of the fine hole produced in the roll plate, and this variation in the depth of the fine hole is also caused by the variation in the anodizing process. It can be said.

  Accordingly, in this embodiment, the conditions in the anodizing process are set so that the variation is large, the apexes are a mixture of a plurality of microprojections and unimodal microprojections, and the heights of the microprojections vary. Produce anti-reflective articles.

  Here, the applied voltage (formation voltage) in the anodic oxidation treatment and the interval between the fine holes are in a proportional relationship, and the variation increases when the applied voltage deviates from a certain range. Thus, for example, using an aqueous solution of sulfuric acid, oxalic acid, and phosphoric acid having a concentration of 0.01 M to 0.03 M, a voltage of 15 V (first step) to 35 V (second step: about 2.3 with respect to the first step). A roll plate for producing an antireflective article in which multi-peaked microprojections and monomodal microprojections coexist and the heights of the microprojections vary can be produced. If the applied voltage fluctuates under this condition, the variation in the space between the micro holes increases, so that for example, an applied voltage can be generated using an AC power source biased by a DC power source, or the applied voltage can be intentionally The variation can be increased by performing anodization using a power source having a large voltage variation rate.

[Lubrication layer creation process]
In the lubrication layer creation step, a fluorine-based liquid lubricant is applied with a certain film thickness to create a lubrication layer. In the application method, various application directions can be widely applied, for example, when applying with a Meyer bar.

[Ionizing radiation irradiation process]
Examples of the ionizing radiation include direct ionizing radiation such as electron beam, α-ray, β-ray, and proton beam, and indirect ionizing radiation such as X, gamma ray, and neutron beam, among which electron beam is preferable. A conventionally known electron beam irradiation apparatus can be used, and the irradiation amount is preferably from 30 kGy to 120 kGy, and if it is less than 30 kGy, the effect of removing dirt such as fingerprints of the present invention cannot be sufficiently obtained, and the coating material can be modified. No decrease in reflectivity is observed. On the other hand, if it exceeds 120 kGy, the resin constituting the microprotrusions is likely to be deteriorated, and the effect of removing the fingerprint cannot be sufficiently obtained due to the decomposition of the coated material.

  In addition, it is preferable to carry out through this ionizing radiation irradiation process to such an extent that the contact angle of the surface of the lubricating layer 3 becomes 100 degrees or more in water contact angle and 50 degrees or more in n-hexane contact angle.

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 number of repetitions of the anodizing treatment and the etching treatment is set to 3 (to 5) each is described, but the present invention is not limited to this, and the number of repetitions is set to other times. In addition, the present invention can be widely applied to the case where the process is repeated a plurality of times and the final process is anodizing.

  The antireflective article of the present invention is preferably used for the purpose of improving the visibility by arranging it on the front side of various image display panels such as a liquid crystal display panel, an electroluminescent display panel, a plasma display panel, etc. However, the present invention is not limited to this. For example, it can be widely applied to the case where it is arranged on the back side of the liquid crystal display panel to reduce the reflection loss of incident light from the backlight to the liquid crystal display panel (in the case of increasing incident light utilization efficiency). Can do. 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.

  Moreover, 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 when using various materials such as acrylate-based, epoxy-based, polyester-based and other electron-beam curable resins, urethane-based, epoxy-based, polysiloxane-based thermosetting resins, and various curing forms of molding resins. Can also be widely applied. For example, the present invention can also be widely applied to the case of shaping by pressing a heated thermoplastic resin.

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

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

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

  Further, in the above-described embodiment, as shown in FIGS. 1 and 7A, the surface connecting the valley bottoms (minimum points of height) between adjacent minute protrusions is a flat surface having a constant height. However, the present invention is not limited to this, and as shown in FIG. 12, the envelope surface connecting the valley bottoms between the microprojections is undulated with a period D (that is, D> λmax) equal to or longer than the longest wavelength λmax of the visible light band. It is good also as a structure. Further, the periodic undulation is constant in only one direction (for example, the X direction) on the XY plane (see FIGS. 7 and 12) parallel to the front and back surfaces of the base material 2 and in a direction (for example, the Y direction) perpendicular thereto. The height may be sufficient, or the two directions (X direction and Y direction) in the XY plane 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 has a distribution that is not constant over the front surface, 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
It is. Usually, D or D _MIN is 1 to 200 μm, preferably 10 to 100 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.

  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 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.

[Example 1]
Along the SP1 to SP3 in FIG. 8, on the substrate 2 (TAC), the fine protrusions 5 (30 parts by mass of monomer EO-modified bisphenol A diacrylate as an ultraviolet curable resin composition, 20 parts by mass of EO-modified trimethylolpropane acrylate, Fine concavo-convex layer forming resin (d = 150 nm between minute protrusions) formed by forming 50 parts by weight of dodecyl acrylate and 1 part by weight of diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide (lucillin TPO) as a polymerization initiator. , Height = 200 nm). Next, Krytox (registered trademark) 101 (general formula: F- [CF (CF ₃ ) CF ₂ O] _n -CF (CF ₃ ) (40 ° C. viscosity 8 mm ² / S)) which is a perfluoroalkyl polyether is used. An anti-reflective article coated with a Mayer bar # 2 to form a lubricating layer was obtained (a coating amount of 4.0 g / m ² ). When the contact angle of this antireflective article was measured, both water and n-hexadecane were 5 degrees or less.

  Next, the antireflection article on which the lubricating layer was formed was irradiated with an electron beam at an intensity of 120 kGy using an electron beam irradiation apparatus (Iwasaki Electric LB1023) to form the lubricating layer 3. When the contact angle of this antireflective article was measured, it was 120 ° with water and 82 ° with n-hexadecane, confirming water and oil repellency.

[Comparative Example 1]
In Example 1, acrylic acid 1H, 1H, 2H, 2H-heptadecafluorodecyl was applied instead of Krytox (registered trademark) 101. When the contact angle of this antireflection article was measured, it was 118 ° with water and 80 ° with n-hexadecane.

[Fingerprint wiping test]
Example 1 and Comparative Example 1 prepared in this manner were each attached to a black acrylic plate with an adhesive layer with the lubricating layer as the front side, and then a finger was pressed to attach the fingerprint. Thereafter, the fingerprint was wiped dry with Zavina Minimax (Fuji Chemical). Dry wiping was performed 10 times with a force of about 3 kg / cm ² , and the appearance after wiping was evaluated. In Example 1, the fingerprint stain could be wiped to such an extent that the fingerprint stain could not be visually recognized, but in Comparative Example 1, a slight color tone was visually recognized on the fingerprint adhering trace and could not be completely wiped off. .

(Antireflection function)
Example 1 and Comparative Example 1 were each bonded to a black acrylic plate with an adhesive layer with the lubricating layer as the front side, and then the SCI value of reflectance was measured using XPM Enable (manufactured by Konica Minolta). The untreated product before forming the lubricating layer was 0.3%, whereas 0.38% in Example 1 and 2.43% in Comparative Example 1.

DESCRIPTION OF SYMBOLS 1 Anti-reflective article 2 Base material 3 Lubricating layer 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 (7)

A method for producing an antireflection article in which microprojections are closely arranged, and the interval between adjacent microprojections is equal to or shorter than the shortest wavelength of an electromagnetic wave for preventing reflection,
A method for producing an antireflective article, comprising: forming a lubricating layer of a fluorine-based lubricant containing perfluoroalkyl polyether on a resin surface constituting the microprojections, and then irradiating with ionizing radiation. The method for producing an antireflective article according to claim 1, wherein the perfluoroalkyl polyether has the following general formula.
[Chemical 1]
F- [CF (CF ₃ ) CF ₂ O] _n —CF ₂ (CF ₃ )
(N represents an integer of 7 to 60.)   The method for producing an antireflective article according to claim 1 or 2, wherein the ionizing radiation is an electron beam having an irradiation intensity of 30 kGy to 120 kGy. The method for producing an antireflection article according to any one of claims 1 to 3, wherein the fluorine-based lubricant has a viscosity at 40 ° C of 1 mm ² / S or more and 1000 mm ² / S or less.   The method for producing an antireflective article according to any one of claims 1 to 4, wherein the resin constituting the fine protrusions is a cured product of a (meth) acrylate compound. At least a part of the microprojections is
6. A multi-peaked microprojection having a plurality of vertices and formed by a shape in which the top portion is divided into ridges related to each vertex by a radial groove formed at the top portion. Manufacturing method of antireflection article.   The image display apparatus which arrange | positions the antireflection article obtained by the manufacturing method in any one of Claim 1 to 6 on the light emission surface of an image display panel.