JP2003340844A - Antireflection article due to sol/gel method and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture an antireflection article provided with fine unevenness for preventing the reflection of light with good durability. <P>SOLUTION: In order to manufacture the antireflection article by forming a fine uneven layer 3 having fine unevenness 2 to the surface of a substrate 1, (A) a master having a fine uneven shape formed thereto is prepared and (B) a master is used as a shaping mold or a duplicated mold produced by the duplication due to once or more templating/reversal of the fine uneven shape on the surface of the master is used to press the shaping mold to the coating film of a sol/gel solution containing an organometal compound applied and formed to the substrate to shape fine unevenness to the surface of the coating film to form a fine uneven layer. The fine uneven layer is further baked appropriately. The shape of the fine unevenness 2 is formed so that the cycle PMAX in the most projected parts of the fine unevenness 2 becomes the minimum wavelength λMIN or less in the vacuum of a wavelength band of visible light and the cross-sectional area occupying ratio of the substrate part in a horizontal cross section continuously and gradually increases from the most projected parts of the fine unevenness 2 to the most recessed parts thereof. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection article which prevents surface reflection of light and can be used for various applications such as a liquid crystal display of a mobile phone and a method for producing the same. In particular, it relates to an antireflection article provided with an antireflection function by a sol-gel method and a method for producing the same.

[0002]

2. Description of the Related Art Articles to which light reflection is applied or articles for which light reflection is desired are found in various applications. For example, it is a window material of the information display section of various devices. As an example, in a mobile phone, a digital camera, etc., an information display unit using a liquid crystal display (LCD) or the like is
In order to protect the display panel from dust, external force, etc., the display panel made of an LCD or the like is not exposed to the outside of the device as it is, but a window member made of a transparent plastic plate or the like is provided on the outside to protect the display panel (Japanese Patent Laid-Open No. Hei 7 (1998)). -66859, etc.).

[0003]

However, when a window material or the like is arranged in front of the display panel, there is a problem that external light is reflected on both front and back surfaces of the window material, and the visibility of the display is deteriorated. In portable devices such as mobile phones, where low power consumption of the display panel is an important factor, the visibility of the display is reduced as a problem of external light reflection, and the display panel is also affected by light reflection by the window material. Since part of the light from the display panel is returned to the display panel side, the light utilization efficiency of the display panel is reduced.
There was also a problem that wasted power was consumed. Although the window material is an example of an antireflection article, other articles for which antireflection is desired or necessary include, for example, various optical components, a transparent touch panel, or the front surface of an advertising display. There are various types such as protective plates.

As a conventional antireflection treatment method, for example, a low-refractive-index layer single-layer film or a multi-layer film of a low-refractive-index layer and a high-refractive-index layer is formed by a method such as vapor deposition, sputtering, or coating. An antireflection layer consisting of
(See Japanese Patent Application Laid-Open No. 001-127852, etc.) is generally used. However, the antireflection layer formed by vapor deposition, sputtering or the like needs to be formed into a thin film whose refractive index and thickness are controlled by one or multiple batch treatments, so that there are problems in product stability, non-defective product ratio, etc. In addition, since batch production is used, there is a problem in that productivity is low and therefore cost is high. Alternatively, as another antireflection treatment,
There is also a technique to reduce the specular light by diffusing (diffuse) reflection on the surface to make it satin-finished, but this method does not increase the light utilization efficiency in terms of diffusing the light and sees it through. There is a problem that the resolution of the image also decreases. That is, for example, the utilization efficiency of the display light of the display panel in the window material of the information display unit.

Therefore, the applicant of the present invention has proposed to solve the problems in these conventional antireflection treatment techniques in Japanese Patent Laid-Open No.
An attempt was made to apply the technique disclosed in Japanese Patent No. 70040, which reduces the surface reflectance by providing the surface with extremely fine fine irregularities having a repetition period equal to or shorter than the wavelength of light. The technique disclosed in the publication will be described here. For optical components such as lenses for which surface reflection should be reduced, a photoresist or the like is applied to the surface of the optical component, exposed, and developed to form a resist pattern. Is produced, and the glass substrate is corroded by the pattern to form fine irregularities directly on the surface of the optical component for each product. However,
The production of each product has a problem that the work efficiency is poor and the productivity (mass productivity) required for industrial products cannot be obtained.

From this point of view, the present inventors have filed a Japanese patent application No. 2
No. 001-352674 (unpublished at the time of filing of the present invention), a replication type is used, and the so-called 2P method (Phot) is used.
A method of shaping a fine concavo-convex layer on a substrate by an o-polymerization method) has been proposed. According to this method, the productivity is improved, but as long as the 2P method is used, the fine uneven layer formed on the surface of the obtained antireflection article is
Since it is made of an organic material called a photocurable resin, it cannot be denied that heat resistance and weather resistance are limited as compared with the case of an inorganic material such as glass.

[0007] That is, an object of the present invention is to provide an antireflection article having fine irregularities on the surface which can reduce unnecessary reflection of light, improve the visibility of the display and improve the utilization efficiency of the light of the display light. , To provide a method of manufacturing with high productivity. Moreover, it is an object of the present invention to provide a manufacturing method in which heat resistance, weather resistance and the like are improved. Another object of the present invention is to provide the antireflection article thus obtained.

[0008]

In order to solve the above-mentioned problems, the method for producing an antireflection article according to the present invention is characterized in that a fine uneven layer having fine unevenness for antireflection is formed on a substrate. A method of manufacturing an antireflection article consisting of:
The fine irregularities have a minimum wavelength λ _MIN in a vacuum in the wavelength band of visible light and a period P at the highest convex portion of the fine irregularities.
When the _MAX, the cross-sectional area of the P _MAX ≦ λ _MIN composed has a relationship, and the material portion in the substrate in a cross section, assuming that the the fine unevenness was cut along a plane perpendicular to the uneven direction The occupancy is such a concavo-convex pattern that it continuously and gradually increases from the most convex part to the most concave part of the fine concavo-convex, and in the steps of manufacturing the antireflection article, (A) Prepare a prototype having a concavo-convex shape, (B) then use the above prototype as a shaping mold, or
Alternatively, it contains a metal-organic compound formed by coating on a base material by making a replica mold by replicating the fine concavo-convex shape on the surface of the master mold once or twice or more by taking and reversing the mold. After pressing the shaping mold against the coating film of the sol-gel liquid, the mold is released, and fine unevenness is formed on the surface of the coating film to form a fine unevenness layer. To produce an antireflection article.

By adopting such a manufacturing method, the fine irregularities on the surface of the antireflection article are once produced by shaping a mold by coating with photoresist, exposing, developing, etc. After that, since it can be formed by shaping from this shaping mold, the productivity is improved first. In other words, even if it takes a long time to manufacture the master mold for initially molding the fine concavo-convex shape, once the master mold is manufactured, the mold can be used repeatedly even when it is used as it is as a mold. is there. In addition, if the original mold is not used as a shaping mold, but a duplicating mold in which the fine concavo-convex shape is taken and inverted from the original mold is used as the shaping mold, the productivity is further improved.
This is because if it is a duplicate mold, a large number of the same can be prepared and manufactured in parallel, and even if the duplicate mold is damaged, it is not necessary to remake it from the original mold. The reason why these productivity improving effects are obtained is that the process of producing the prototype by the photolithography method has the highest difficulty, and the time, labor, and manufacturing cost are large.

Moreover, in the production method of the present invention, the fine uneven layer formed on the surface of the antireflection article is formed by the sol-gel method using an organometallic compound as a starting material, so that an inorganic layer can be obtained. The heat resistance, weather resistance, and the like can be improved as compared with the case where the resin layer is formed by the 2P method or the like. In addition, the hardness of fine irregularities can be obtained and the cleaning resistance can be improved. In the manufacturing method of the present invention, the fine concavo-convex layer may be fired, but may not be fired. When not fired, the base material of the antireflection article may be an organic material having poor heat resistance such as a resin, as well as an inorganic material such as glass, and in addition, it does not require a time-consuming firing step, thus improving productivity. Good, for example, for continuous strip base material such as resin sheet,
It is possible to further improve productivity by continuous processing.

The reason why light reflection is prevented by the fine irregularities is, to put it simply, if fine irregularities having a size equal to or less than the wavelength of light to be antireflection are provided on the surface of the material, the gap between the surface and the air will be reduced. This is because the refractive index change can be made substantially gentle and continuous, so that light reflection, which is a phenomenon that occurs when the refractive index change is abrupt and discontinuous, can be prevented.

In addition, the antireflection function of the present antireflection article provided with such fine irregularities is not the light diffusive antireflection that reduces the specular reflection light due to irregular reflection such as satin finish, but the article surface Since it is realized by easing the abrupt change in refractive index at the interface with air, it is non-light diffusive, and the light reflectance is reduced and the light transmittance is improved. Therefore, when used as a window material for information display parts such as displays,
The article has improved visibility of display and improved utilization efficiency of display light.

Further, in the method for producing an antireflection article of the present invention, in the above-mentioned production method, the substrate is an inorganic substrate, and after releasing the shaping mold, fine irregularities are shaped on the surface. The manufacturing method of firing the fine concavo-convex layer was adopted.

In the present manufacturing method, the base material is further limited to an inorganic base material, and the firing step is included as a manufacturing step. By such a manufacturing method, the fine uneven layer contains an organic component. Even in this case, the organic component can be burned and eliminated to form an inorganic layer, which has heat resistance,
The weather resistance, hardness, cleaning resistance, etc. can be surely improved. Therefore, for example, a post-treatment that requires heat resistance, such as when a transparent conductive film such as an ITO film is further formed on the fine irregularities by a physical method, can be easily performed.

The antireflection article of the present invention is an antireflection article having a structure manufactured by any one of the above manufacturing methods.

By using the antireflection article having such a structure, the antireflection article can enjoy the effects described in the above-mentioned manufacturing methods.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

[Outline] FIG. 1 is an explanatory view (cross-sectional view) for conceptually explaining one embodiment of the method for producing an antireflection article by the sol-gel method according to the present invention. In the embodiment described here, the original mold is not used as it is as a shaping mold, but a replica mold is once duplicated from the original mold, and this replica mold is used as the shaping mold.

First, as shown in FIG. 1A on the upper right side of the drawing,
The shaping die 41 for forming fine unevenness has fine unevenness 2A having an uneven shape opposite to that of the fine unevenness 2 to be given to the antireflection article on the shaping surface. As the shaping mold 41, more preferably in terms of productivity, as shown in FIG. 1B on the upper left side of the drawing, a master pattern in which a fine concavo-convex shape is formed by an exposure method or the like (the fine concavo-convex shape is first formed). Instead of using 40, it is preferable to use, as the shaping die 41, a duplication die obtained by duplicating the fine concavo-convex shape from the original die 40 by die casting / inversion as shown in FIG. Of course, if there is no problem in terms of productivity and the like, the prototype 40 may be used as it is as the shaping mold 41.

Then, as shown in FIG. 1A, a sol-gel solution containing an organometallic compound is applied on the base material 1 to form a coating film 3A. Then, as shown in FIG. 1 (D), if the coating film 3A is pressed by the shaping die 41 and then the shaping die 41 is released, as shown in FIG. 1 (E), the coating film 3A has its surface. A fine concavo-convex layer 3 having the fine concavo-convex 2 formed thereon is obtained, and an antireflection article 10 having a configuration in which the fine concavo-convex layer 3 is laminated on the substrate 1 is obtained.

The antireflection article 1 can be used as it is.
Since the surface of No. 0 is formed with the fine unevenness 2 having a desired uneven shape, an antireflection effect can be obtained, but in order to improve the strength, durability and the like of the fine unevenness layer 3 having the fine unevenness 2 on the surface. For this reason, it is preferable to burn the organic component in the fine concavo-convex layer 3 through a firing step. In the case of firing, the base material is of course a material that can withstand the firing temperature, which is suitable when the base material is an inorganic material such as glass.

The above-mentioned fine unevenness 2 peculiar to the present invention is a conventionally known antireflection treatment of a method of scattering (diffuse reflection) light by utilizing a matte surface (matte) by unevenness having a size larger than the light wavelength. Or, unlike the anti-glare treatment, it is unevenness having a shape peculiar to the present invention and having a size equal to or less than the wavelength of visible light. With such fine irregularities, a light reflection preventing effect can be obtained.

Since FIG. 1 is conceptual, the antireflection article 10 has a flat plate shape, but the shape is not limited to the flat plate shape. The fine irregularities 2 can also be formed on two or more surfaces of the antireflection article.

Further, in the antireflection article and the shaping mold, the fine irregularities have an inverse concavo-convex relationship, but in the description of the present invention, when these fine irregularities are explicitly distinguished, the Those having a fine concavo-convex pattern 2 and those having a pattern on the shaping mold have a fine concavo-convex pattern 2A, which are used differently depending on the signs. However, in the shaping mold by the duplicating mold, the fine unevenness between the shaping mold and the master mold depends on the number of duplication operations by taking and reversing to obtain it.
There are cases where there is an inverse concavo-convex relationship and cases where it does not. When the duplication operation is performed once or an odd number of times, the shaping mold and the master have an inverse concavo-convex relationship, but when the duplication operation is twice or an even number of times, they have the same concavo-convex relationship.

[Fine unevenness] The fine unevenness 2 has an antireflection effect for the following reasons. That is, due to the fine irregularities 2, a rapid and discontinuous change in refractive index between the fine irregularity layer 3 forming the surface of the antireflection article and the outside (air) is converted into a continuous and gradual change in refractive index. It is possible to change. This is because the reflection of light is a phenomenon caused by a discontinuous and abrupt refractive index change at the material interface. Therefore, by making the refractive index change on the article surface spatially and continuously, Light reflection on the article surface is reduced. The fine concavo-convex layer 3 is normally transparent and allows light to pass through. However, even if it is opaque, an antireflection effect of reducing the surface reflection can be obtained.

Hereinafter, the reason why the antireflection effect is obtained by the fine irregularities 2 formed on the surface of the fine irregularity layer 3 will be described in detail on the assumption that the fine irregularity layer 3 (and the substrate 1) is transparent.

2 to 4 are conceptual views for conceptually explaining the refractive index distribution obtained by the fine unevenness 2 formed on the surface of the fine unevenness layer 3. First, FIG. 2 shows, as an antireflection article, a fine concavo-convex layer 3 laminated on a base material 1 (not shown) and provided with fine concavo-convex portions 2 on the surface thereof. A state is shown in which a large number of fine unevennesses 2 having the Z-axis direction as the unevenness direction are arranged on the surface of the fine unevenness layer, that is, on the XY plane at Z = 0, occupying a space.

In the present invention, the fine unevenness 2 is formed as shown in FIG.
As the in period at its most convex portion 2t is taken as P _MAX, the P _MAX is, since the in the minimum wavelength in a vacuum wavelength band of visible light are not more than lambda _MIN, fine irregularities forming surface For the light reaching the medium, the medium (fine concavo-convex layer and air)
Even if there is a spatial distribution in the refractive index of, the distribution does not directly affect the light because it is a distribution with a size below the wavelength of interest, and it acts as an averaged one. . Therefore, the reflection of light can be prevented by making the distribution such that the averaged refractive index (effective refractive index) continuously changes as the light advances.

In the present invention, the period P _MAX of the most convex portion 2t is the maximum distance between the most convex portions 2t of the adjacent fine irregularities 2 and is the individual fine irregularities. May be regularly arranged and have periodicity (distances between adjacent fine irregularities are the same), but may be non-periodic (distances between adjacent fine irregularities are not uniform).

Then, in FIG. 2, the Z axis is set in the direction of the normal to the envelope surface of the fine concavo-convex layer 3 as an orthogonal coordinate system.
In addition, the X axis and the Y axis are set in the plane orthogonal to it. Then, now, light enters from the outside of the fine concavo-convex layer into the fine concavo-convex layer, travels inside the fine concavo-convex layer, and proceeds in the vicinity of the surface of the fine concavo-convex layer in the negative direction of the Z-axis, Just assume that the Z-axis coordinate is at z.

Then, for the light at Z = z, the refractive index of the medium has a specific fine unevenness 2 on the surface of the fine unevenness layer 3, so strictly speaking, at Z = z, it is orthogonal to the Z axis. Distribution f in the XY plane (transverse section: horizontal section)
Looks like it has (x, y, z). That is, in the XY plane, the cross section of the fine concavo-convex layer 3 has a refractive index n.
_b (about 1.5), and the other part, specifically, the part of air a has a refractive index n _a (= about 1.0) (see FIG. 3). However, in reality, for light, refraction on a spatial scale smaller than that wavelength (if the wavelength of the light to be anti-reflection has a distribution, consider the minimum wavelength λ _MIN of the wavelength band). As a result of the refractive index distribution acting as an average, the effective refractive index of the averaged result has a refractive index distribution f (x, y, in the XY plane).
z) integrated in the XY plane,

[0032]

[Equation 1]

It becomes As a result, the distribution of the effective refractive index (n _ef ) becomes a function n _ef (z) of only z (see FIG. 4).

Therefore, if the cross-sectional area of the convex portion of the fine concavo-convex layer 3 in the fine concavo-convex 2 is such that it continuously increases toward the concavity, the fine concavo-convex pattern (in the XY plane). Since the area ratio between the layer portion and the air portion continuously changes in the Z-axis direction, the effective refractive index n _ef (z) is a continuous function with respect to z.

On the other hand, in general, let us consider a case where light enters from a medium having a refractive index n _{0 to} a medium having a refractive index n ₁ . Now, for the sake of simplicity, consider an incident angle θ = 0 ° (normal incidence). However, the incident angle is an angle with respect to the normal line of the incident surface. In this case, the reflectance R at the medium interface does not depend on the polarized light and the incident angle, and becomes the following [Formula 2].

[0036]

[Equation 2]

Therefore, the fact that the change of the (effective) refractive index in the Z direction is a continuous function means that the refractive index at Z = z, two points separated by a minute distance Δz in the Z direction (light traveling direction). n _ef (z) is n ₀ , and the refractive index n at Z = z + Δz
_{When ef} (z + Δz) is n ₁ ,

If Δz → 0, then n ₁ → n ₀

And (from the definition of the continuous function),
From [Equation 2],

R → 0

It becomes

Here, to be more precise, the wavelength of the light in the object is λ, the wavelength in vacuum is n, and the refractive index of the object is n.
Then λ / n, which is generally smaller than λ to some extent. However, since the refractive index when the object is air is n≈1, it may be considered that λ / n≈λ. However, since the material used for the fine concavo-convex layer usually has a refractive index of about 1.5, the wavelength (λ / n _b ) in the base material having the refractive index n _b is about 0.7λ. Considering this point, in the part of the fine unevenness 2,
Looking at the part on the air side (recesses of the fine unevenness 2),

P _MAX ≦ λ _MIN

When the condition (1) is satisfied, the effect of reducing the reflectance by averaging the refractive index can be expected. However,

Λ _MIN / n _b ≤P _MAX ≤λ _MIN

In the case of, the contribution of the fine concavo-convex layer portion (convex portions of the fine concavo-convex 2) cannot be expected to be at least completely reduced by the average refractive index. However, it still has an antireflection effect as a whole due to the contribution in the air portion. And

P _MAX ≤λ _MIN / n _b

When the condition (1) is also satisfied, the condition that the period P _MAX is smaller than the shortest wavelength is completely satisfied in both the air part and the fine concavo-convex layer part, so the antireflection effect by averaging the refractive index is It will be more complete. Specifically, λ
_MIN is the lower limit of the visible light wavelength band of 380 nm, and n _b is 1.
If it is 5, λ _MIN / n _b may be 250 nm, that is, P _MAX may be 250 nm or less.

Next, the shape of the fine concavo-convex pattern 2 is the material portion of the fine concavo-convex layer in the section (horizontal section) assuming that the fine concavo-convex section is cut by a plane (XY plane) orthogonal to the concavo-convex direction. The cross-sectional area occupancy is the highest convex portion (top) of the fine irregularities.
From the bottom to the most recessed part (valley bottom). For this purpose, it is sufficient that at least a part of the fine uneven ridge has an oblique slope, but even if the fine uneven ridge has a vertical side as well as a slope as shown in FIG. good. Particularly preferably, the shape is such that the most convex portion converges completely to 0, and the most concave portion completely converges to 1. Specifically, for example, FIG.
Shapes as shown in (B) and FIG. 5 (C) may be mentioned. However, as shown in FIG. 5 (D) or FIG. 5 (E), if the shape is such that the most convex portion is asymptotically close to 0, or that the most concave portion is asymptotically close to 1. A certain effect can be obtained. If the shape of the fine unevenness satisfies these conditions,
Any shape is acceptable.

For example, the vertical cross-sectional shape of each fine unevenness 2 is a wavy shape only by a curve such as a sine wave as shown in FIG. 5 (A) (see also FIG. 2), FIG. 5 (B) and FIG. 5 (C). ), Such as the shape of a straight line such as a triangle, or the trapezoidal shape in which the most convex portion of the triangle as shown in FIG. 5D forms a flat surface, or the shape between the adjacent triangles as shown in FIG. 5E. For example, the recess has a flat surface. However, FIG. 5 (D) and FIG. 5 (E)
As described above, in the shape having the flat surface at the most convex portion or the most concave portion, the larger the area ratio of the flat surface at the most convex portion or the most concave portion is, the larger the change in effective refractive index becomes. It will be continuous. In that respect, the performance is inferior. However, even in this case, the effective refractive index can be continuously changed from the most convex portion of the fine irregularities to the most concave portion. Therefore, in terms of antireflection performance, the smaller the area ratio of the flat surface of the most convex portion or the most concave portion, the better.

Further, the effective refractive index n _ef (z) is a function of the Z direction from the air to the fine concavo-convex layer, and n _a to n _b
In order to continuously change the shape, the shape as shown in FIG. 5 (B) or FIG. 5 (C) in which the cross-sectional area occupation ratio of the fine concavo-convex layer converges to 0 at the most convex part of the fine concavo-convex. The most preferable is a shape (that is, a pointed shape) and the cross-sectional area occupancy continuously converges to 1 at the most recessed portion.

Next, the horizontal cross-sectional shape of each fine unevenness is
The shape is arbitrary such as a circle (for example, FIG. 2), an ellipse, a triangle, a quadrangle, a rectangle, a hexagon, and other polygons. The horizontal cross-sectional shape does not have to be the same from the most convex part to the most concave part of the fine unevenness. Therefore, the three-dimensional shape of the fine unevenness is, for example, a three-dimensional shape of the fine unevenness when the horizontal cross-sectional shape is circular and the vertical cross-sectional shape is an equilateral triangle, and a fine three-dimensional shape when the horizontal cross-sectional shape is circular and the vertical cross-sectional shape is triangular. The three-dimensional shape of unevenness is an oblique cone, the three-dimensional shape of fine unevenness when the horizontal cross-sectional shape is a triangle and the vertical cross-sectional shape is an equilateral triangle is a triangular pyramid,
When the horizontal cross-sectional shape is quadrangular and the vertical cross-sectional shape is triangular, the three-dimensional shape of fine irregularities is a quadrangular pyramid.

The arrangement of the fine irregularities in the horizontal plane is not limited to the two-dimensional arrangement shown in FIG.
Like the linear groove-shaped fine unevenness 2 illustrated in the perspective view of FIG.
A one-dimensional arrangement may be used, and both can be effective. However, in the case of the one-dimensional arrangement, anisotropy occurs in which the direction in which the antireflection effect is obtained and the direction in which the antireflection effect is not obtained occur depending on the relationship with the amplitude direction of the light wave. Therefore, the perspective view of FIG.
The two-dimensional arrangement as illustrated in the plan views of (B) and (C) is preferable because it has no directivity.

The three-dimensional shapes of the individual fine concavities and convexities may be all the same or may not be the same. Further, when the individual fine irregularities 2 are two-dimensionally arranged, the periods may be all the same or may not be the same in the individual fine irregularities.

The height H of the fine irregularities is determined according to the desired reflectance reduction effect and the maximum wavelength of the visible light band incident on the surface of the fine irregularities layer. For example, JP-A-50-70
In the case of designing on the basis of the reflectance, the height of fine irregularities, and the relationship with the light wavelength described in JP-A No. 040 (particularly FIG. 3), for example, the reflectance in the visible light band is 2% (untreated). If the target is to reduce the height to less than half of the case of glass), the minimum height H _MIN is 0.2λ _MAX or more, that is,

H _MIN ≧ 0.2λ _MAX

If the aim is to reduce the reflectance in the visible light band to 0.5% or less,

H _MIN ≧ 0.4λ _MAX

It is preferable that Here, λ
_MAX is the maximum wavelength in vacuum in the visible light wavelength band. The reflectance decreases as the height H of the fine irregularities increases from zero, but when reaching a height that satisfies the above-mentioned inequality condition, a significant effect can be obtained. Specifically, for example, the maximum wavelength of the emission spectrum is λ _MAX
= 640 nm fluorescent lamp is used, H _MIN ≧ 0.
2λ _MAX = 128 nm. That is, H _MIN is 12
It should be 8 nm or more. In addition, if one considers a solar ray with a maximum wavelength of the spectrum λ _MAX = 780 nm, then H _MIN
≧ 0.2λ _MAX = 156 nm, that is, H _MIN is 156
It may be set to nm or more. Also, the minimum height H _{M IN} and the period P
_In relation to _MAX , the ratio of minimum height H _MIN / period P _MAX is
It is about 1/2 to 4/1.

Here, the specific shape and size of the fine irregularities
For example, the vertical cross section is sinusoidal and the horizontal cross section is
Many circular conical shapes are regularly arranged in two dimensions.
It is an aggregate that is placed, and the cycle period P_MAXIs 50-250n
m, minimum height H_MINIs the cycle P _MAX1.5 times
And so on.

[Manufacture of Shaped Mold] As a molding mold used for molding the coating film by the sol-gel method, a master mold having a fine concavo-convex shape formed first may be used, but in terms of productivity and the like. More preferably, it is preferable to use a replica mold produced from the master mold once or twice or more through a replicating step by taking and reversing the mold. That is, first, a prototype (this is also referred to as an original plate or a mother plate) is first made, and then a duplication operation for making a duplicated mold from this prototype is performed once or twice or more times, and as a result, Another replication type (also referred to as a main plate or a master plate) is adopted as a shaping mold used for a coating film by the sol-gel method. By adopting such a method, the method is excellent in industrial productivity and cost.

There is no particular limitation on the manufacturing method of the original mold as long as it has the necessary fine irregularities, and productivity, cost, etc. are taken into consideration. Then, an appropriate one may be used. The production of the prototype is a step of first forming an uneven shape for shaping the fine unevenness 2, and is a so-called microfabrication technique in the semiconductor field, that is, utilizing light (including an electron beam) for pattern formation. Exposure methods can be used. However, in the case of a semiconductor, since the side surface of the uneven shape is usually a vertical surface and it is not particularly necessary to form a slope as in the present invention, in the present invention, fine processing is performed so that a slope can be formed.

An electron beam drawing method can be used as the fine processing technique as described above. In this method, first, a resist layer is formed on a glass substrate, and then the resist layer is exposed by an electron beam drawing method, developed, and patterned to form a resist pattern layer. After that, the glass substrate is corroded by a dry etching method or the like using the resist pattern layer as an etching mask to form fine irregularities on the glass substrate. At this time, side surfaces are etched during etching to form slopes. Further, the resist pattern layer itself may be directly used as a corrosion mask at the time of corroding the glass substrate, but in order to form a deep uneven shape having a slope, it is preferable to provide a metal layer of chromium or the like on the glass substrate. After that, a resist film is formed to obtain a resist pattern layer,
It is preferable that the metal pattern layer formed by using the resist pattern layer is used as a corrosion mask.

When forming a pattern on the resist film, a laser drawing method can be used in addition to the electron beam drawing method. In the laser drawing method, a laser interference method used for producing holograms, diffraction gratings, etc. can be used. The diffraction grating has a one-dimensional arrangement, but a two-dimensional arrangement is also possible by changing the angle and performing multiple exposure. However, in the laser interferometry, the resulting fine irregularities are usually arranged regularly, but in the electron beam drawing method, predetermined drawing pattern information is stored in advance in the storage device as digital data and the drawing pattern information is used. , ON / OFF of scanning electron beam,
Or modulates the strength. Therefore, in addition to regular arrangement, irregular arrangement is also possible. Further, since the laser drawing method and the electron beam drawing method have respective advantages and disadvantages, an appropriate method and conditions are selected in consideration of design specifications, purpose, productivity and the like.

Next, as a method for producing a replica mold to be used as a shaping mold from the above prototype, a known method, for example,
A metallic duplicate mold can be produced by plating the prototype with a metal such as nickel and peeling off the plating layer (electroforming method). Alternatively, the duplication mold may be plated again, and the duplicated mold may be used as the shaping mold to form the shaping mold through two or more duplication operations. The shape of the shaping mold for the coating film formed by the sol-gel method may be a plate shape, a sheet shape, a block shape, etc., and may be appropriately selected depending on the shape, application, etc. of the antireflection article. The shaping mold may be made of metal such as nickel, but may be made of resin such as silicone resin. For example, it is a shaping mold which can be formed into a sheet shape made of a resin and can have a continuous strip shape.

[Sol-Gel Method] By the way, the sol-gel method is
It is known as a method of forming an inorganic coating film made of a metal oxide from a coating film obtained by applying a sol-gel solution containing an organometallic compound such as alkoxysilane as a precursor of a metal oxide on a substrate. Recently, it is also known as a method for forming an organic-inorganic composite film. In these sol-gel methods, when the base material is a resin sheet or the like, a firing step of heat-treating the coating film at high temperature to burn and eliminate organic components is not included, but when the base material is an inorganic material such as glass. Has
Since the base material can withstand high heat, the coating film can be further baked to form a complete inorganic film.

As a method for further forming a concavo-convex shape on the surface of such a coating film by the sol-gel method, there are, for example, JP-A-62-225273 and JP-A-6-94.
907, or "Micropatterning by sol-gel method" (Ceramics, vol37, No.
3, p161-164, 2002) and the like. According to these documents, a coating film in a plastic state formed by applying a solution of a sol-gel solution containing a metal alkoxide, the shaping mold is pressed against the surface of the coating film, a diffraction grating,
There has been proposed a method of shaping a fine concavo-convex shape such as a groove of an optical disk substrate.

As the sol-gel liquid, a known sol-gel liquid applied to various base materials such as resin sheets and glass can be used, but in the present invention, it may exhibit plasticity at least when pressing the shaping mold. preferable. If the time to exhibit plasticity between application of the coating film and curing is short and the workability of shaping is poor, in order to increase the plasticity, for example, a resin or a low-molecular compound that increases the viscosity of the solution is used. It is also preferable to appropriately add the above.

As the organometallic compound used as the sol-gel liquid, a compound whose viscosity increases due to a polycondensation reaction or a crosslinking reaction can be used. Examples of the organometallic compound include the general formula R _n M (OR ′) _m
The metal alkoxide compound represented by, its hydrolyzate, etc. are mentioned. In the above formula, M is Si, Ti,
Zr, Al, Ca, Na, Pb, B, Sn, Ge and other metals are represented, R and R ′ are alkyl groups such as methyl group, ethyl group, propyl group and butyl group, and n and m are n +
m represents an integer that is the valence of the metal M. Therefore, for example, when the metal M is silicon Si, the above general formula is R _n S
i (OR ') _n-4 .

Further, of the metal alkoxy compounds as described above
To give a specific example, Si (OCH₃)_Four, Si (OC
₂H_Five)_FourSilicon-based alkoxide compounds such as Ti (OC₃
H₇)_Four, Ti (OC_FourH₉)_FourTitanium-based alkoxides such as
Compound, Zr (OC₃H₇)_Four, Zr (OC_FourH₉)_FourEtc.
Ruconium-based alkoxide compound, Al (OC
₃H₇)_Four, Al (OC_FourH₉)_FourAluminum-based alcohol such as
Xide compound, NaOC₂H_FiveSodium alkoxide such as
Examples thereof include side compounds. Furthermore, silicon-based alkoxy
Specific examples of the compound include methyltriethoxysila
[[CH₃) Si (OC₂H_Five)₃], Methyltripropo
Xysilane [(CH ₃) Si (OC₃H₇)₃], Dimethyl
Diethoxysilane [(CH₃)₂Si (OC₂H_Five)₂〕etc
Is mentioned.

Further, as the organometallic compound, a compound represented by the general formula X
A metal alkoxide compound represented by _n M (OR ′) _m [wherein X is a reactive functional group such as an amino group, a carboxyl group, a glycidyl group, an acryloyloxy group, a methacryloyloxy group], for example, a metal is In the case of silicon, a compound called a so-called silane coupling agent can be used.

The resin or low molecular weight compound added to improve plasticity during shaping is, for example, an acrylic resin, a thermoplastic resin such as polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polytetraethylene glycol, or the like. A low molecular weight organic compound such as the polyether compound can be used. For the sol-gel solution, water or an alcohol such as methanol or ethanol, a ketone such as methyl ethyl ketone or methyl isobutyl ketone, or a solvent such as ester such as ethyl acetate or butyl acetate is appropriately used. In the sol-gel solution, an acid such as hydrochloric acid or an alkali is appropriately used as a catalyst for promoting the hydrolysis reaction of the organometallic compound or its hydrolyzate.

[Shaping by Shaped Mold] Then, when the shape-forming mold as described above is pressed against the coating film formed by applying the sol-gel solution and released, desired fine irregularities are formed on the surface of the coating film. Is shaped to obtain a fine concavo-convex layer. Further, although the coating film is in a plastic state during shaping, the reaction is further advanced after shaping to completely solidify the coating film to form a fine concavo-convex layer. In addition, you may heat appropriately at the time of shaping.

[Firing] After releasing the shaping mold, if the base material is an inorganic base material such as glass that can withstand the firing temperature, the fine concavo-convex layer obtained after shaping is further fired. Then, when the organic component remains, it may be baked to form an inorganic layer. By firing, the fine uneven layer having fine unevenness on the surface has more excellent heat resistance, weather resistance, hardness, cleaning resistance, and the like. Therefore, for example, an antireflection article can be obtained to which a post-treatment that requires heat resistance, such as when a transparent conductive film such as an ITO film is further formed on the fine irregularities by a physical method, can be applied. The firing temperature is usually 200 ° C.
The above is, for example, 450 ° C. or the like. In addition, even if a resin or a low molecular weight organic compound is added to the sol-gel liquid so that it can be easily shaped in a shaping mold by going through a firing step, these organic components are burned and no organic component remains. A fine uneven layer can be formed as the inorganic layer. Therefore,
It is possible to prevent deterioration of performance such as heat resistance, weather resistance, hardness, and cleaning resistance due to the remaining of these organic components.

Even if the base material is an inorganic base material such as glass, if the performances such as heat resistance, weather resistance, hardness, and cleaning resistance are excessive, the firing step is It can be omitted. If the firing step is omitted, the processing time required for it is shortened, and the productivity is improved. In addition, when the base material is an organic material and is a continuous strip-shaped base material such as a resin sheet, the firing step cannot be performed, but continuous processing is also possible and the manufacturing method is excellent in productivity.

[Substrate] The substrate 1 is not particularly limited. Inorganic materials such as glass (including ceramics), synthetic resins such as thermoplastic resins and thermosetting resins can be used. When the coating film is baked, an inorganic material is preferable as the base material in terms of heat resistance during baking. As the material of the base material, a material suitable for the application of the antireflection article may be used. A transparent material is usually used as the base material.

Examples of the base material of the inorganic material include glass such as soda glass and quartz glass, and ceramics. Further, a thermoplastic resin is typically used as the base material of the organic material, and examples thereof include methyl poly (meth) acrylate, ethyl poly (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate. Acrylic resin such as copolymer (however, (meth) acrylic means acrylic or methacrylic. ], Polycarbonate resin, polypropylene, polymethylpentene, cyclic olefin polymer (typically, norbornene resin, etc., but for example, product name "Zeonor" manufactured by Nippon Zeon Co., Ltd., "Arton" manufactured by JSR Co., Ltd. , Etc.) and other polyolefin resins, polyethylene terephthalate,
Examples thereof include thermoplastic polyester resins such as polyethylene naphthalate, polyamide resins, polystyrene, acrylonitrile-styrene copolymers, polyether sulfones, polysulfones, cellulosic resins, vinyl chloride resins, polyether ether ketones and polyurethanes.

[Application of Antireflection Article] The antireflection article according to the present invention may have any shape such as a three-dimensional shape, a plate or a sheet, and the application is not particularly limited.
However, since the fine irregularities of the antireflection surface are extremely fine, it is better to pay attention to dirt and scratches, so the fine irregularities are preferably not exposed on the outer surface but provided on the inner surface. It is suitable for use, or for use provided inside the device. The applications to which the present invention can be applied are
It is not limited to the applications exemplified below.

For example, it is a window material for an information display section in various devices such as mobile phones and digital cameras. In these display parts, a resin or glass window material such as a plate or a molded product is arranged in front of a display panel such as an LCD. Since the antireflection article as a window material is exposed on the outside, the fine irregularities peculiar to the present invention are not provided in terms of resistance to scratches and stains, and the fine irregularities are provided on the inner back surface side. Is preferred. The information display section may be displayed by a mechanical means such as a mechanical analog meter typified by a timepiece other than a display panel such as an LCD, or may be a window material of these. The window material has a flat plate shape, but may have a projection or the like on the periphery from the viewpoint of assembly and design.

As the device having the windowed information display section as described above, a personal computer, a personal digital assistant (PDA) such as an electronic notebook, a personal digital assistant, a calculator, a CD player, or the like can be used in addition to a mobile phone or a clock. DVD player,
Various portable music players such as MD players and semiconductor memory type music players, or video tape recorders,
There are electronic devices such as IC recorders, video cameras, digital cameras, label printers, and electric products such as electric rice cookers, electronic pots, and washing machines.

Further, in the plate-shaped or sheet-shaped antireflection article, a transparent substrate such as a transparent plate used for a transparent touch panel and the like can be mentioned. The transparent touch panel is for adding an input function to the display unit.
As it is assembled as a separate part from the display panel such as CRT,
A gap remains between the display panel and the transparent touch panel, causing light reflection. Therefore, light reflection can be prevented by using a transparent base material forming the back surface side of the transparent touch panel as an antireflection article having the back surface provided with fine irregularities peculiar to the present invention.

The transparent touch panel is, for example, a PDA such as an electronic notebook or a portable information terminal (device), or
Car navigation system, POS (point-of-sale information management) terminal, portable order input terminal, ATM (cash automatic teller machine), facsimile, fixed telephone terminal, mobile phone, digital camera, video camera, personal computer, display for personal computer, Electronic devices such as television receivers, television monitor displays, ticket vending machines, measuring instruments, calculators, electronic musical instruments, copiers, ECR (cash register), or electric appliances such as washing machines and microwave ovens. Used for. The antireflection article of the present invention may also be used as various optical components. For example, a lens of a camera, a window member of a finder of a camera, a lens of eyeglasses, a Fresnel lens of an overhead projector, an output extraction window of a laser device, a light input window of an optical sensor, a telescope lens, and the like.

[0083]

The present invention will be described in more detail with reference to the following examples.

Example 1 A shaping mold and a sol-gel solution were prepared in the following manner, and fine irregularities 2 were formed on the surface as shown in FIG. 1 (E).
A transparent antireflection article 10 having a structure in which the fine concavo-convex layer 3 having the above was laminated on the substrate 1 was produced.

(1) Fabrication of shaping mold: After forming a metallic chromium film on one surface of a quartz glass substrate, a positive resist was spin-coated thereon to form a resist film. Then
After drawing mesh-shaped drawing data having a vertical and horizontal cycle of 300 nm on this resist film with an electron beam drawing apparatus, it is developed with a developing solution,
A resist pattern layer having openings in the mesh opening area was formed. Then, the metal chromium film exposed from the opening of the resist pattern layer was dry-etched with a chlorine-based gas. Then, the glass substrate was dry-etched with a fluorine-based gas using the resist pattern layer and the metal chromium film as an etching resistant layer to prepare a prototype (mother plate) on which desired fine irregularities were formed. Next, from this prototype,
By electroplating, a replica mold (nickel stamper) made of a nickel-plated plate having a thickness of 80 μm was produced as a shaping mold.

(2) Preparation of sol-gel solution: As the sol-gel solution, a high molecular weight SiO ₂ sol solution and a low molecular weight SiO ₂ sol solution were prepared, respectively, and mixed to prepare.

(2-1) Preparation of high molecular weight SiO ₂ sol solution: Methyltrimethoxysilane (MTMOS) 2 was added to a four-necked flask equipped with a stirrer, a nitrogen introduction tube, and a discharge tube.
2.7 g (0.17 mol) and 14 ml of methanol were added and mixed, and the mixture was cooled to 0 ° C. And water and hydrochloric acid which, _{respectively, H 2 O / MTMOS = 1.30} , HCl / MTMO
S was added at 0.105 and stirred at room temperature for 10 minutes, then, while introducing dry nitrogen, at 70 ° C. for 3 hours, 1
After stirring at a speed of 50 rpm, the solvent was distilled off under reduced pressure to obtain a high molecular weight polymer composed of a highly viscous polymer. The high molecular weight polymer was dissolved in methyl ethyl ketone so that the solid content concentration was 1.5 mass% assuming that the high molecular weight polymer was hydrolyzed and condensed to MeSiO _1.5 (where Me is a methyl group). A high molecular weight SiO ₂ sol solution was obtained. The molecular weight of this high molecular weight substance was 42000 in terms of weight average molecular weight, which was measured by GPC (gel permeation chromatography) using polystyrene as a standard sample.

(2-2) Preparation of low molecular weight SiO 2 sol solution: Solid content concentration was 3% by weight assuming that methyltriethoxysilane (MTEOS) was ideally hydrolyzed and condensed to SiO ₂ or MeSiO _1.5. So that MT
EOS was dissolved in a solvent, methyl ethyl ketone, and stirred for 30 minutes until the liquid temperature became stable at 25 ° C. Next, 0.005N concentration of hydrochloric acid as a catalyst was added in an equimolar amount to the alkoxy group of MTEOS, and a hydrolysis reaction was performed at 25 ° C. for 3 hours. Next, a mixture of sodium acetate and acetic acid was added as a curing agent, and the mixture was stirred at 25 ° C for 1 hour,
A low molecular weight SiO2 sol solution was obtained.

(3) Preparation of sol-gel solution: the above low molecular weight S
The above-mentioned high molecular weight SiO ₂ sol solution is added to the io ₂ sol solution in an amount of 30.
Mass% was added to give a sol-gel liquid for coating.

(4) Formation and application of coating film: thickness 250
The above sol-gel solution was applied to the surface of a substrate made of a polyethylene terephthalate sheet having a thickness of 10 μm so that the film thickness after removing the solvent was 10
The coating film was applied so as to have a micron size, and dried at 60 ° C. for 5 minutes to form a coating film. Then, using the shaping mold of the above (1), desired fine irregularities were shaped on the surface of the coating film by a hot pressing method. That is, the shaping mold was pressed on the base material on which the SiO ₂ layer was applied and formed under the heat and pressure condition of [120 ° C., 1 Pa (10 kgf / cm ² )]. As a result, on the surface of the coating film on the substrate obtained by peeling off the shaping mold, an inverse concave-convex pattern of the shaping mold is formed to form a fine unevenness layer having desired fine unevenness on the surface. A transparent antireflection article was obtained in which the layers were laminated on a substrate.

When the reflectance of the antireflection article having the above-mentioned fine concavo-convex layer on the surface of the substrate was measured, the luminous reflectance was 0.3%, and the antireflection effect was recognized.

Example 2 A shaping mold and a sol-gel solution were prepared as follows, and fine irregularities 2 were formed on the surface as shown in FIG. 1 (E).
A transparent antireflection article 10 having a structure in which the fine concavo-convex layer 3 having the above was laminated on the substrate 1 was produced.

(1) Preparation of shaping mold: After forming a metallic chromium film on one surface of a quartz glass substrate, a positive resist was spin-coated thereon to form a resist film. Then
After drawing mesh-shaped drawing data having a vertical and horizontal cycle of 300 nm on this resist film with an electron beam drawing apparatus, it is developed with a developing solution,
A resist pattern layer having openings in the mesh opening area was formed. Then, the metal chromium film exposed from the opening of the resist pattern layer was dry-etched with a chlorine-based gas. Then, the glass substrate was dry-etched with a fluorine-based gas using the resist pattern layer and the metal chromium film as an etching resistant layer to prepare a prototype (mother plate) on which desired fine irregularities were formed. Next, from this prototype,
By electroplating, a replica mold (nickel stamper) made of a nickel-plated plate having a thickness of 80 μm was produced as a shaping mold.

(2) Preparation of sol-gel solution: As the sol-gel solution, a high molecular weight SiO ₂ sol solution and a low molecular weight SiO ₂ sol solution were prepared and mixed to prepare a sol-gel solution.

(2-1) Preparation of high molecular weight SiO ₂ sol solution: Methyltrimethoxysilane (MTMOS) 2 was added to a four-necked flask equipped with a stirrer, a nitrogen inlet tube, and a discharge tube solution.
2.7 g (0.17 mol) and 14 ml of methanol were added and mixed, and the mixture was cooled to 0 ° C. And water and hydrochloric acid which, _{respectively, H 2 O / MTMOS = 1.30} , HCl / MTMO
S was added at 0.105 and stirred at room temperature for 10 minutes, then, while introducing dry nitrogen, at 70 ° C. for 3 hours, 1
After stirring at a speed of 50 rpm, the solvent was distilled off under reduced pressure to obtain a high molecular weight polymer composed of a highly viscous polymer. The polymer was dissolved in methyl ethyl ketone so that the solid content concentration was 1.5% by mass, assuming that the polymer was hydrolyzed and condensed to MeSiO _1.5.
An iO ₂ sol solution was obtained. The molecular weight of this high molecular weight substance was measured by GPC (gel permeation chromatography) using polystyrene as a standard sample.
It was 000.

(2-2) Preparation of low molecular weight SiO 2 sol solution: Methyltriethoxysilane (MTEOS) is ideally SiO ₂ or MeSiO _1.5 (where Me is a methyl group).
MTEOS was dissolved in a solvent, methyl ethyl ketone, so that the solid content concentration was 3% by weight, assuming that it had been hydrolyzed and condensed to 30.degree. C. until the liquid temperature stabilized at 25.degree.
Stir for minutes. Next, as a catalyst, hydrochloric acid having a concentration of 0.005 N was added in an equimolar amount with the alkoxy group of MTEOS to give 25
The hydrolysis reaction was performed at 3 ° C. for 3 hours. Next, a mixture of sodium acetate and acetic acid was added as a curing agent, and 2
It stirred at 5 degreeC for 1 hour, and obtained the low molecular weight SiO2 sol solution.

(3) Preparation of sol-gel solution: the above low molecular weight S
iO to ₂ sol solution, the high molecular weight SiO ₂ sol solution 30
A sol-gel solution for coating was prepared by adding 5% by mass of polyethylene glycol to the solution after the addition.

(4) Formation of coating film and shaping: thickness 2 mm
The above sol-gel solution was applied to the surface of the glass base material of No. 1 so that the film thickness after removal of the solvent would be 10 μm, and dried at 60 ° C. for 5 minutes to form a coating film. Then, using the shaping mold of the above (1), desired fine irregularities were shaped on the surface of the coating film by a hot pressing method. That is, a shaping mold is applied to a substrate on which a SiO ₂ layer is formed by coating [120 ° C., 1 Pa (10 kgf /
cm ² )] was pressed under the hot pressing condition. As a result, an inverse concavo-convex pattern of the shaping mold was formed on the surface of the coating film on the substrate obtained by peeling the shaping mold, and a fine concavo-convex layer having desired fine concavities and convexities on the surface was obtained. Furthermore, after peeling off the shaping mold,
The fine concavo-convex layer was baked at 450 ° C. for 30 minutes to obtain a desired antireflection article as a final fine concavo-convex layer.

When the reflectance of the antireflection article having the above-mentioned fine concavo-convex layer on the surface of the substrate was measured, the luminous reflectance was 0.5%, and the antireflection effect was recognized.

[0100]

(1) According to the method for producing an antireflection article of the present invention, the fine irregularities on the surface of the antireflection article are compared with the case where each article is directly formed by applying photoresist, exposing, developing or the like. The productivity is good because it can be formed by once forming a shaping mold and then shaping from this shaping mold. Moreover, since the fine concavo-convex layer formed on the surface is formed by the sol-gel method, an inorganic-based layer is obtained, and the heat resistance, as compared with the case where it is formed as a resin layer by the 2P method,
The weather resistance and the like can be made excellent. Further, the hardness of fine irregularities can be obtained, and the cleaning resistance and the like can be improved. When the fine concavo-convex layer after shaping is not fired, an organic material having poor heat resistance such as resin can be used as the base material in addition to the inorganic material such as glass. Moreover, the productivity is good in that there is no time-consuming firing step, and it is possible to further improve the productivity by continuously treating a continuous strip-shaped substrate such as a resin sheet. Further, the antireflection function imparted to the antireflection article by the production method of the present invention does not reduce light reflection by specular diffuse reflection such as satin finish, but the sharp refractive index of the interface between the article surface and air. Since it is realized by alleviating the change, the light transmittance is improved as much as the light reflectance is reduced. Therefore, it is possible to obtain an antireflection article that can improve the visibility of the display when used as a window material of an information display unit such as a display and can improve the utilization efficiency of the light of the display light.

(2) If the base material is an inorganic base material and the fine irregularity layer is baked, the organic component is burned and disappears even if the fine irregularity layer contains the organic component. It can be formed into a layer, and the heat resistance, weather resistance, hardness, cleaning resistance and the like can be more surely made excellent. Therefore, for example, a post-treatment that requires heat resistance, such as when a transparent conductive film such as an ITO film is further formed on the fine irregularities by a physical method, can be easily performed.

(3) According to the antireflection article of the present invention, the effects described in the above respective manufacturing methods can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view conceptually explaining the method for producing an antireflection article of the present invention in one form thereof.

FIG. 2 is a diagram (1) for conceptually explaining the distribution of the effective refractive index obtained by fine irregularities.

FIG. 3 is a diagram (part 2) for conceptually explaining the distribution of the effective refractive index obtained by fine irregularities.

FIG. 4 is a diagram (part 3) for conceptually explaining the distribution of the effective refractive index obtained by fine irregularities.

FIG. 5 is a cross-sectional view illustrating some of the (vertical) cross-sectional shapes of fine irregularities.

FIG. 6 is a cross-sectional view illustrating some of arrangements of fine irregularities in a horizontal plane.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base material 2 Fine unevenness 2A (on a shaping mold) Fine unevenness 2t (The finest unevenness 2) Most convex part 3A (Before shaping) Coating film 3 Fine unevenness layer 10 Antireflection article 40 Prototype 41 Molding ( replicating) n the refractive index n _a refractive index (air) n _b refractive index (substrate) n ₀ the refractive index n ₁ the refractive index n _ef (Z) effective refractive index H _MIN (minute unevenness) minimum height P _MAX cycle R Reflectivity λ _MIN Minimum wavelength λ _MAX Maximum wavelength

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/1335 B29L 7:00 4F204 // B29L 7:00 11:00 11:00 G02B 1/10 Z F term (reference) 2H042 BA04 BA13 BA15 BA16 2H091 FA37X FB02 FB08 FC19 FC25 FD06 FD23 2K009 AA04 BB02 BB11 CC02 CC21 DD02 DD06 DD11 4F100 AA01A AA20 AH08A AK42 AT00B BA02 DD07B GB41 JL02 JL09 JM01A JM10A JN06A 4F202 AB19 AC06 AF01 AG01 AG05 AH73 CA01 CB01 CD04 CD05 CK11 4F204 AA33 AA36 AB01 AB03 AC06 AG01 AG05 AH73 AH78 EA03 EA04 EB01 EB29 EE02 EE21 EE23 EF27 EK10 EK13 EK17 EK24

Claims (3)

[Claims] 1. A method for producing an antireflection article, comprising a fine irregularity layer having fine irregularities for antireflection formed on a surface of a substrate, wherein the fine irregularities are vacuum in a wavelength band of visible light. The minimum wavelength in the inside is λ _MIN , and the cycle at the most convex part of the fine irregularities is P
When the _MAX, the cross-sectional area of the P _MAX ≦ λ _MIN composed has a relationship, and the material portion in the substrate in a cross section, assuming that the the fine unevenness was cut along a plane perpendicular to the uneven direction The occupancy is such a concavo-convex pattern that it gradually and gradually increases as it goes from the most convex part to the most concave part of the fine concavo-convex, and as a step when manufacturing the antireflection article, sequentially,
(A) First, prepare a prototype having a fine concavo-convex shape,
(B) Next, the above-mentioned master is used as a shaping mold, or a micro-concavo-convex shape on the surface of the above-mentioned master is replicated one or more times by taking and reversing the mold to prepare a replica mold, and the replica mold is produced. Using a coating film of a sol-gel liquid containing an organometallic compound formed by coating on a substrate, after pressing the shaping mold, the mold is released, and fine irregularities are formed on the surface of the coating film. A method for producing an antireflection article by a sol-gel method, wherein each step is performed to form a fine concavo-convex layer. 2. The antireflection article by the sol-gel method according to claim 1, wherein the base material is an inorganic base material, and after releasing the shaping mold, the fine concavo-convex layer having fine concavities and convexities formed on the surface is baked. Manufacturing method. 3. An antireflection article produced by the method for producing an antireflection article by the sol-gel method according to claim 1.