JP2015187637A - Antireflective article, image display device, method for manufacturing antireflective article, molding die for antireflective article, and method for manufacturing molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve scratch resistance of an antireflective article relating to a moth-eye structure.SOLUTION: An antireflective article 5 has an antireflection effect by a fine concavo-convex pattern on a surface thereof, in which large projections 16 are discretely and randomly disposed on the surface, and minute projections 15 are tightly arranged at an interval equal to or smaller than the shortest wavelength of a wavelength band of electromagnetic waves as a target of antireflection. The large projections 16 have height larger than height of the minute projections 15 arranged between the large projections 16 and have a wider root part than the longest wavelength of the wavelength band as a target of antireflection. Micro projections 16A are tightly arranged at an interval equal to or shorter than the shortest wavelength of the wavelength band of electromagnetic waves as a target of antireflection on at least a top part of the large projection.

Description

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

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

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

  Various uses have been proposed for such antireflection articles. For example, it can be placed on the light exit surface of various image display devices to reduce the reflection of external light such as sunlight on the screen to improve image visibility, or to form the microprojections on a sheet or plate-like transparent substrate Furthermore, by constructing a touch panel using an electrode in which a transparent conductive film such as ITO (indium tin oxide) is formed on the microprojection group, light reflection between the touch panel electrode and various adjacent members is performed. It has been proposed to reduce the occurrence of interference fringes, ghost images, and the like. Patent Document 4 proposes a method in which minute protrusions are formed on the side surface of an image display panel of a touch panel to reduce reflection of emitted light from the image display panel, thereby improving visibility and light utilization efficiency.

  Patent Document 5 also provides a sufficient antireflection function for this type of antireflection article, even when a plurality of vertices are formed on the tops of minute protrusions due to poor resin filling during the molding process. It describes what you can do.

  Further, Patent Document 6 discloses a method for producing an antireflection article by a molding process using a molding die in which micro holes are closely arranged, and a part of the micro holes are deep holes. Thus, there has been proposed a method for reducing the arrangement unevenness of the microprojections. In the case of this method, the fine protrusions produced by the shaping process have different heights, and can improve the scratch resistance of the antireflection article.

  By the way, the antireflection article according to this kind of moth-eye structure has a problem that the scratch resistance is still insufficient in practice. That is, for example, when an anti-reflective article comes into contact with another object, the anti-reflective function is locally deteriorated, and white turbidity, scratches, etc. occur at the contact location, resulting in poor appearance.

  In particular, when an antireflection article is produced in a film shape and laminated with another optical film, and further laminated with an antireflection article having the same kind of film shape, scratch resistance is still not practical. There is a sufficient problem, and in these cases, the microprojections may be locally worn or the antireflection article may be in close contact with the contact target.

Japanese Patent Laid-Open No. 50-70040 Special Table 2003-531962 Japanese Patent No. 4632589 JP 2003-50673 A JP 2012-037670 A JP2013-119636A

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

  The present inventor conducted extensive research to solve the above problems, and provided a large protrusion having a large protrusion with a moth-eye structure on the top, which was larger than the minute protrusion related to the moth-eye structure. The idea of preventing contact of other members with the fine protrusions produced between the large protrusions while ensuring the antireflection function has been reached, and the present invention has been completed. In the following, a microprojection having a plurality of vertices is referred to as a multimodal microprojection, and a microprojection having only one apex is referred to as a single-peak microprojection in contrast to the multimodal microprojection. In the following, when simply referred to as a microprojection, both a single-peak microprojection and a multimodal microprojection are included. Moreover, each convex part which forms each vertex which concerns on a multimodal microprotrusion and a monomodal microprotrusion is called a peak suitably.

    Specifically, the present invention provides the following.

(1) In an anti-reflective article that is anti-reflective by a fine uneven surface shape,
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. The microprotrusions are arranged.

  According to (1), the large protrusion functions as a spacer, and the contact of the other member with the minute protrusion can be reduced. As a result, it is possible to effectively avoid damage to the microprojections and improve the scratch resistance. Further, since the large protrusions are also provided with the small protrusions, it is possible to ensure the same antireflection function as when only the small protrusions are arranged on the entire surface.

(2) In (1),
The large protrusion is
1 / cm ² or more, are arranged by the density of 30 / cm ² or less.

  According to (2), it is possible to sufficiently reduce the contact of other members to the microprojections without impairing the antireflection function by the microprojections.

(3) In (1) or (2),
The large protrusion is
The height is 1 μm or more and 100 μm or less.

  According to (3), it is possible to easily and reliably produce a large protrusion with a desired size by various production methods.

(4) In (1), (2), or (3),
The large protrusion is
The width of the base portion is 5 μm or more and 30 μm or less.

  According to (4), it is possible to easily and reliably produce a large protrusion with a desired size by various production methods.

(5) In (1), (2), (3), or (4),
The large protrusion is
It is produced at the location of the defect related to the minute projections between the large projections.

  According to (5), it is possible to arrange the large protrusions by effectively using the defective portion.

(6) In (1), (2), (3), (4), or (5),
The anti-reflective article is
It is a film shape and is arranged on the exit surface side of the image display panel.
The large protrusion is
When arranged on the exit surface side of the image display panel, the image display panel is arranged at a location overlapping with a light shielding portion between pixels of the image display panel.

  According to (6), large protrusions can be made inconspicuous.

  (7) An image in which the antireflection article of (1), (2), (3), (4), (5), or (6) is disposed on the exit surface side and / or the entrance surface side of the image display panel Display device.

  According to (7), for example, when the touch panel sensor film is disposed on the exit surface of the image display panel and / or when the backlight device is disposed on the entrance surface of the image display panel, the antireflection article is disposed and visually recognized. In the case of improving the property and the light utilization efficiency, it is possible to prevent the minute protrusions provided on the antireflection article from being damaged. As a result, it is possible to prevent the minute protrusions from being worn and to prevent the antireflection article from coming into close contact with the contact target.

(8) In the method of manufacturing an antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The method of manufacturing the antireflection article includes:
On the surface of the substrate, a molding resin layer creating step for creating a molding resin layer,
A molding step of creating the microprotrusions on the base material by a molding process of the molding resin layer using a molding die; and
A large protrusion forming step of forming the large protrusion on the surface of the base material on which the minute protrusion is formed;

  According to (8), it is possible to reduce the contact of other members with the micro-projections by creating large projections by post-processing after creating the micro-projections and causing the large projections to function as spacers. it can. As a result, it is possible to effectively avoid damage to the microprojections and improve the scratch resistance. Further, since the large protrusions are also provided with the small protrusions, it is possible to ensure the same antireflection function as when only the small protrusions are arranged on the entire surface.

(9) In the method of manufacturing an antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The method of manufacturing the antireflection article includes:
On the surface of the base material, a pretreatment process for creating a pilot hole related to the large protrusion,
By repeating the anodizing process and the etching process, a minute recess corresponding to the minute protrusion between the large protrusions is formed between the pilot holes, and corresponding to the minute protrusion provided on the large protrusion in the pilot hole. By creating a recess, a recess creating step of creating a molding die by creating a large recess corresponding to the large projection,
On the surface of the substrate, a molding resin layer creating step for creating a molding resin layer,
And a molding step of creating the minute projections and the large projections on the base material by a molding process of the molding resin layer using the molding die.

  According to (9), it is possible to create microprojections and large projections using a mold for shaping such as a roll plate, and to treat the substrate by the same process as when no large projections are provided, An antireflective article having a large protrusion can be produced.

(10) In the mold for molding used for the production of antireflection articles,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The mold for molding is
A minute recess corresponding to the minute protrusion and a large recess corresponding to the large protrusion are created,
The large recess is
Made by discrete random arrangement,
The depth is deeper than the minute recess, and the surface side is wider than the longest wavelength of the wavelength band for preventing reflection,
The minute recess is
Between the large-sized recesses, they are arranged closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection.

  According to (10), an antireflective article in which microprojections and large protrusions are mixed can be produced by a shaping process. In this antireflective article, the large protrusions function as spacers, and the microprojections of other members Contact to the protrusion can be prevented. As a result, it is possible to effectively avoid damage to the microprojections and improve the scratch resistance. Further, since the large protrusions are also provided with the small protrusions, it is possible to ensure the same antireflection function as when only the fine protrusions are arranged on the entire surface.

(11) In the manufacturing method of the molding die used for production of the antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The method for producing the mold for molding is as follows:
On the surface of the base material, a pretreatment process for creating a pilot hole related to the large protrusion,
By repeating the anodizing process and the etching process, a minute recess corresponding to the minute protrusion between the large protrusions is formed between the pilot holes, and corresponding to the minute protrusion provided on the large protrusion in the pilot hole. A recess creating step of creating a recess and creating a large recess corresponding to the large protrusion.

  According to (11), it is possible to produce an antireflective article in which microprojections and large protrusions are mixed by a shaping process. In this antireflective article, the large protrusions function as spacers, and other members Contact to the fine protrusions can be prevented. As a result, it is possible to effectively avoid damage to the microprojections and improve the scratch resistance. Further, since the large protrusions are provided with the minute protrusions, it is possible to ensure the same antireflection function as when only the minute protrusions are arranged on the entire surface.

  With respect to the antireflection article according to the moth-eye structure, it is possible to improve the scratch resistance as compared with the conventional art.

It is a figure which shows the image display apparatus which concerns on 1st Embodiment of this invention. It is a perspective view which shows the antireflection film applied to the image display apparatus of FIG. It is sectional drawing which shows the surface shape of the antireflection film of FIG. 2 in detail. It is a figure where it uses for description of arrangement | positioning of a large sized protrusion. It is a figure where it uses for description of the distance between adjacent protrusions. It is a figure with which it uses for description of a vertex. 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 multimodal microprotrusion. It is a photograph which shows a multimodal microprotrusion. It is a figure where it uses for description of the manufacturing process of the antireflection film of FIG. It is a figure where it uses for description of the roll plate which concerns on the manufacturing process of FIG. It is a figure which shows the preparation processes of the roll plate of FIG. It is a figure where it uses for description of repetition of an anodizing process and an etching process. It is a figure where it uses for description of control of height distribution. It is a figure which shows the example different from FIG. It is a figure where it uses for description of the manufacturing process of the antireflection film which concerns on 2nd Embodiment of this invention. It is a figure which shows the antireflection film which concerns on 3rd Embodiment of this invention. It is sectional drawing of the antireflection film of FIG. It is a conceptual sectional view showing the form in which the envelope surface of the valley bottom of the microprojection exhibits an uneven surface (waviness).

[First Embodiment]
FIG. 1 is a diagram showing an image display apparatus according to the first embodiment of the present invention. In this image display device 1, a backlight device 3 is disposed on the back side (incident surface side) of the image display panel 2 using a liquid crystal display panel, and light emitted from the backlight device 3 is incident on the image display panel 2 to be desired. The image of is displayed. In the image display device 1, a touch panel sensor film 4 is disposed on the light emission surface side of the image display panel 2. Here, the sensor film 4 for the touch panel is a film material that constitutes the touch panel. In the image display device 1, the electrodes provided on the sensor film 4 for the touch panel are driven by a drive circuit (not shown) to constitute the touch panel. In addition, various structures, such as a capacitance type and a resistance type, can be widely applied to the sensor film 4 for a touch panel. In the image display device 1, the touch panel sensor film 4 is placed and disposed on the exit surface of the image display panel 2, whereby the exit surface of the image display panel 2 and the side surface of the image display panel 2 of the touch panel sensor film 4 are arranged. An air layer is interposed between the two.

  Therefore, in this embodiment, the antireflection film 5 is arranged on the side surface of the image display panel 2 of the touch panel sensor film 4. Here, the antireflection film 5 is a film-like antireflection article having a moth-eye structure. Thereby, the image display apparatus 1 reduces the reflection in the incident surface of the sensor film 4 for touchscreens, improves visibility, and improves the utilization efficiency of light. Here, the antireflection film 5 may be prepared separately from the sensor film 4 for the touch panel, and then attached to the sensor film 4 for the touch panel, and the transparent film material on the image display panel 2 side of the sensor film 4 for the touch panel. Alternatively, it may be produced integrally with the touch panel sensor film by producing a fine uneven shape.

  As indicated by reference numeral 5A, the antireflection film is emitted from the image display panel 2 instead of the side surface of the image display panel 2 of the sensor film 4 for touch panel or in addition to the side surface of the image display panel 2 of the sensor film 4 for touch panel. It may be provided on the surface. In this case, the image display panel 2 may be prepared separately and attached to the exit surface of the image display panel 2, or a member constituting the exit surface of the image display panel 2 (for example, a linear polarizing plate base material) It may be produced integrally with the image display panel 2 by producing a fine uneven shape on the side surface of the sensor film 4 for touch panel.

  Accordingly, in the image display device 1, regarding the configuration on the emission surface side of the image display panel 2, the internal reflection of the image display device 1 is reduced to improve the visibility, and further, the light use efficiency is improved.

  FIG. 2 is a perspective view showing the detailed configuration of the antireflection film 5 as seen from the image display panel 2 side. The antireflection film 5 has a minute projection 15 having a moth-eye structure on the surface of the base material 11 in the shape (form) of a transparent film, a shape larger than the minute projection 15, and a minute size similar to the minute projection 15. A large protrusion 16 having a protrusion at least at the top is disposed. In the antireflection film 5, large protrusions 16 are disposed by discrete random arrangement, and a large number of minute protrusions 15, 15 </ b> A, 15 </ b> B related to the moth-eye structure are closely arranged irregularly between the large protrusions 16. Thereby, the antireflection film 5 functions the large protrusion 16 as a spacer to prevent contact of other members with the minute protrusion 15. Thereby, the antireflection film 5 effectively avoids the damage of the microprotrusions 15 related to the moth-eye structure and improves the scratch resistance.

[Large protrusion]
Here, the large protrusion 16 is formed in a substantially circular shape when seen in a plan view, and is provided with a minute protrusion 16A having a moth-eye structure at least at the top. The large protrusion 16 is formed in a conical shape with a rounded top, a truncated cone shape with a flat top, a semi-spherical shape, or the like when viewed as a whole by a curved surface connecting the roots of the small protrusion 16A. In addition, in the large protrusion 16, in addition to the top, the fine protrusion 16A may be provided in a portion other than the top. As a result, the antireflection film 6 is provided with the small protrusions 16A on the large protrusions 16 so as to ensure the same antireflection function as when only the small protrusions are arranged on the entire surface, and the large protrusions 16 are used as spacers. It is made to function and the damage of the microprotrusions 15 between the large protrusions 16 due to contact of other members or the like is prevented.

The large protrusion 16 functions as a spacer and prevents contact between the other member and the minute protrusion 15, and as shown in FIG. 3, the large protrusion 16 is made to have a height H ₁₆ higher than that of the minute protrusion 15. The large protrusion 16 is provided with a plurality of small protrusions 16A at least at the top, so that the height of the large protrusion 16 viewed from the root of the large protrusion 16 among the apexes of the plurality of small protrusions 16A provided on the top. the highest vertex, the height H ₁₆ is defined. Here the height H of the minute projection 15, by variations as will be described later, large projections 16, the variation in consideration, so that the height H ₁₆ than the highest height microprojections 15 becomes high Produced. Here from the viewpoint of ensuring sufficient antireflection function, the microprojections 15, with respect to the longest wavelength .lambda.max the Prevention reflection, the average value HAVG height satisfies the relation of _{H AVG} ≧ 0.2 × λmax is necessary. As Accordingly .lambda.max = 780 nm, the average value _{H AVG} height of the minute projection 15 is greater than or equal to 156 nm. As will be described later, when a single-peak microprojection and a multi-peak microprojection are mixed, the standard deviation σ of the height of the microprojection 15 is about 30 nm (see FIG. 9). Thus, the large protrusion 16 can be produced with a height H ₁₆ of 300 nm or more, and contact of other members with the micro protrusion 15 can be substantially prevented. However, from the viewpoint of easily and surely manufacturing the large protrusion 16 with a desired size by various manufacturing methods as described later, the large protrusion 16 is preferably manufactured with a height H ₁₆ of 1 μm or more. More preferably, the thickness is preferably 5 μm or more.

However, if the height H ₁₆ becomes too high, the base portion of the large protrusion 16 must be made sufficiently large to ensure sufficient strength, and as a result, the antireflection function by the micro protrusion 15 is locally degraded. Or image quality degradation may be perceived. Therefore, in this embodiment, the large projection 16 has a height _{H 16} is manufactured by 100μm or less.

The large protrusions 16, so as not to function as a spacer damaged by contact with other members is impaired, the width D ₁₆ of the base portion is produced by sufficiently large. Specifically, the large protrusion 16 is manufactured such that the width D _{16 of the} base portion is larger than the longest wavelength λmax of the wavelength band for preventing reflection. However, from the viewpoint of easily and reliably producing the large projection 16 in a desired size by various production methods as described later, the large projection 16 is preferably produced with a root portion width D ₁₆ of 1 μm or more. It is even more preferable that the thickness is 5 μm or more.

However, if becomes too large width D ₁₆ of root portion, by the image quality degradation is likely, such as the perceived width D ₁₆ is manufactured by 30μm or less.

The large protrusions 16 can prevent the contact of other members to the fine protrusions more reliably by increasing the arrangement density. However, if the arrangement density becomes too high, image quality deterioration may be perceived. In addition, when arranged regularly, interference fringes or the like may occur. As a result, the large protrusions 16 are produced with a density of 1 piece / cm ² or more and 30 pieces / cm ² or less and discrete random arrangement.

  As shown in FIG. 4, the large protrusions 16 are arranged so as to be on the black matrix BM, which is a light shielding portion provided between the pixels of the image display panel 2, thereby making the large protrusions less noticeable. As a result, the antireflection film 5 is set on the image display panel 2 so that the black matrix and the large protrusions 16 overlap each other.

In this embodiment, as shown by a one-dot chain line in FIG. 4, for example, the area allocated to one of the large protrusions 16 (reciprocal of the arrangement density) when the large protrusions 16 are disposed at the above-described disposition density. The entire surface of the antireflection film 5 is divided by a rectangular area (somewhere), and one large protrusion 16 is arranged in each divided area. In this arrangement, the large protrusions 16 are arranged on the black matrix BM at random positions in the region. In addition, the example of FIG. 4 is an example in the case of arrange | positioning the large protrusion 16 by the density of about 1 piece / mm < ² > by this.

[Micro projections between large projections]
The microprojections 15 between the large projections 16 are irregular between the large projections 16 so that the distance d between the adjacent microprojections 15 is equal to or less than the shortest wavelength Λmin (d ≦ Λmin) of the wavelength band of the electromagnetic wave for preventing reflection. Is more closely arranged. In this embodiment, the shortest wavelength is set to the shortest wavelength (380 nm) in the visible light region in consideration of individual differences and viewing conditions, in order to improve visibility by placing the image display device. The interval d is set to 100 to 300 nm in consideration of variation. Further, the adjacent minute protrusions 15 related to the distance d are so-called adjacent minute protrusions 15, which are in contact with the bottom part of the minute protrusion which is the base part on the base material 11 side. In the antireflection film 5, the minute protrusions 15 are closely arranged so that when a line segment is formed so as to sequentially follow the valley portions between the minute protrusions, a polygonal region surrounding each minute protrusion 15 is seen in a plan view. A mesh-like pattern formed by connecting a large number is produced. The adjacent minute protrusions 15 related to the distance d are protrusions that share a part of the line segments constituting the mesh pattern.

  The minute protrusions 15 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. Regarding the interval between the microprotrusions, which is one of these conditions, for example, as disclosed in Japanese Patent Application Laid-Open No. 50-70040, Japanese Patent No. 4632589, etc., when the microprojections are regularly arranged at a constant period, An interval d between adjacent minute protrusions is a period P (d = P) of the protrusion arrangement. 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 microprojections is set to H ≧ 0.2 × λmax = 156 nm (assuming λmax = 780 nm) from the viewpoint of exhibiting a sufficient antireflection effect.

  However, when the minute protrusions are irregularly arranged as in this embodiment, the distance d between the adjacent minute protrusions varies. More specifically, as shown in FIG. 5, when viewed from the normal direction of the front surface or the back surface of the substrate, when the microprojections are not regularly arranged at a constant cycle, the repetition cycle of the microprojections Depending on P, the distance d between adjacent protrusions cannot be defined, and even the concept of adjacent protrusions causes doubt. Therefore, in such a case, it is calculated as follows.

  (1) That is, first, an in-plane arrangement of microprojections (planar shape of projection arrangement) is detected using an atomic force microscope (AFM) or a scanning electron microscope (SEM). FIG. 5 is an enlarged photograph actually obtained by an atomic force microscope. Since the AFM data is accompanied by the in-plane distribution data of the height of the microprojections, this photo can be said to be a photo showing the in-plane distribution of height by luminance. A photograph and a frequency distribution graph, which will be described later, serve to explain the distance between adjacent protrusions. The microprojection group of the present invention will be described later with reference to FIGS. 7 and 15 to 21.

  (2) Subsequently, the maximum point of the height of each microprotrusion (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. 6 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. 5, and the portions indicated by black dots in this figure are the maximum points of the respective minute 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 (Delaunary Diagram) having the detected maximum point as a generating point is created. Here, Delaunay diagram is obtained by dividing the Voronoi region adjacent to the Voronoi region when the Voronoi division is performed with each local maximum as the generating point, and connecting the adjacent generating points with line segments. This is a net-like figure made up of triangular aggregates. Each triangle is called a Delaunay triangle, and a side of each triangle (a line segment connecting adjacent generating points) is called a Delaunay line. 7 is a diagram in which the Delaunay diagram (represented by white line segments) obtained from FIG. 6 is superimposed on the original image of FIG. The Delaunay diagram has a dual relationship with the Voronoi diagram. Voronoi division means that a plane is divided by a net-like figure made up of a closed polygon aggregate defined by perpendicular bisectors of line segments (Droney lines) connecting between adjacent generating points. A network figure obtained by Voronoi division is a Voronoi diagram, and each closed region is a Voronoi region.

  (4) Next, the frequency distribution of the line segment length of each Delaunay line, that is, the frequency distribution of the distance between adjacent maximum points (hereinafter referred to as the distance between adjacent protrusions) is obtained. FIG. 8 is a frequency distribution histogram prepared from the Delaunay diagram of FIG. In addition, as shown by reference numerals 15A and 15B in FIG. 5, when a concave portion such as a groove exists at the top of the projection or the top is divided into a plurality of peaks, from the obtained frequency distribution, A frequency distribution is created by removing data resulting from a fine structure having a concave portion at the top of the protrusion and a fine structure in which the top is split into a plurality of peaks, and selecting only the data of the protrusion main body itself.

  Specifically, in the fine structure in which there is a concave portion on the top of the protrusion, or in the fine structure related to a multi-peak microprotrusion in which the top is divided into a plurality of peaks, the single peak property that does not have such a fine structure From the numerical range in the case of a microprotrusion, the distance between adjacent maximum points is clearly greatly different. Thus, by removing the corresponding data using this feature, only the data of the projection body itself is selected and the frequency distribution is detected. More specifically, for example, about 5 to 20 adjacent single-peaked microprojections are selected from an enlarged photograph of the group of microprojections as shown in FIG. 5, and the value of the distance between adjacent maximum points is selected. A value that deviates in a direction that is clearly smaller than the numerical range obtained by sampling (usually data that is 1/2 or less of the average distance between adjacent maximum points obtained by sampling) ) To detect the frequency distribution. In the example of FIG. 8, data having a distance between adjacent maximal points of 56 nm or less (the leftmost small mountain indicated by the arrow A) is excluded. FIG. 8 shows a frequency distribution before such exclusion processing is performed. Incidentally, such exclusion processing may be executed by setting the above-described maximum inspection filter.

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

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

  In addition, the reference position when measuring the height of the microprotrusions described above uses the valley bottom (minimum point of height) between the adjacent microprotrusions as the reference for the height 0. However, when the height of the valley bottom itself varies depending on the location, (1) First, an area sufficient for the average value to collect the average height of the valley bottoms measured from the front surface or the back surface of the base material 11. Calculate in (2) Next, a surface having the average height and parallel to the front surface or the back surface of the substrate 11 is considered as a reference surface. (3) Then, the height of each microprotrusion from the reference plane is calculated by setting the reference plane to 0 again.

If the microprojections are irregularly arranged, the maximum value dmax = d AVG ₊ 2σ adjacent protrusions distance obtained in this way, the average value H _AVG height of the minute projections are regularly arranged It has been found necessary to satisfy the above-mentioned conditions of the case. 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 minute protrusions is set to _HAVG ≧ 0.2 × λmax = 156 nm (assuming λmax = 780 nm) in order to exhibit a sufficient antireflection effect. However, from the viewpoint of ensuring the antireflection function to a practically sufficient level, the average inter-protrusion distance dave may be set so that dave ≦ λmin.

5 to 9, dmax = 234 nm ≦ λmax = 780 nm, and it can be seen that the antireflection effect can be sufficiently achieved by satisfying the condition of dmax ≦ λmax. In addition, since the shortest wavelength λmin in the visible light band is 380 nm, it can be seen that the sufficient condition dmax ≦ λmin for exhibiting the antireflection effect in all visible light wavelength bands is also satisfied. Since dave ≦ dmax, it can be seen that the condition of dave ≦ λmin is also satisfied. When the average protrusion the height _H AVG = 178 nm Also, the average projection height _{H AVG} ≧ 0.2 × λmax = _156nm becomes (as the longest wavelength .lambda.max = 780 nm in the visible light wavelength band), realizing a sufficient antireflection effect It can be seen that the conditions regarding the height of the minute protrusions to satisfy the above 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 microprojection, 84% or less However, it turns out that the conditions (178 nm or more) concerning the height of protrusion are satisfied.

[Multimodal microprotrusions]
The antireflection film 5 is provided with a mixture of monomodal microprojections and multimodal microprojections. Here, the multimodal microprotrusions are microprotrusions having a plurality of vertices, and when the microprotrusions are viewed in plan from the tip side, they are divided into a plurality of regions by grooves formed outward from substantially the center, Each of the plurality of regions is formed to be a peak related to each vertex. The multi-modal microprotrusions are produced by forming a microhole having a corresponding shape, and the shape when the microprotrusions are viewed in plan view from the tip side is disclosed in Japanese Patent Laid-Open No. 2012-037670. It has different characteristics from the multimodal microprotrusions caused by poor filling of the resin during mold processing. Unimodal microprojections are microprojections with only one vertex. As described above, the anti-reflection film 5 reduces damage to the microprojections 15 even if the large projections 16 are damaged and other members come into contact with each other due to the mixture of the single-peak microprojections and the multi-peak microprojections. Thus, local deterioration of the antireflection function, scratching, and the like can be prevented, whereby the antireflection film 5 can further improve the scratch resistance.

FIG. 10 is a cross-sectional view (FIG. 10 (a)), a perspective view (FIG. 10 (b)), and a plan view (FIG. 10 (c)) for explaining the multimodal microprotrusions. Note that FIG. 10 is a diagram schematically showing for easy understanding, and FIG. 10A is a diagram showing a cross section taken along a broken line connecting the vertices of continuous microprotrusions. 10B and 10C, the xy direction is the in-plane direction of the base material 11, and the z direction is the height direction of the microprojections. In the antireflection film 5, many microprotrusions 15 are gradually cut in a cross-sectional area (a plane perpendicular to the height direction (a plane parallel to the XY plane in FIG. 10) as it moves away from the base material 11 toward the apex. 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 (15A), the apex was three (15B), Furthermore, there were those having four or more vertices (not shown). The shape of the unimodal microprotrusions 15 can be approximated by a round shape at the top like a paraboloid of revolution or a sharp shape at the apex like a cone. On the other hand, the shape of the multimodal microprotrusions 15A and 15B is approximately approximated by a shape in which a groove-shaped recess is cut in the vicinity of the top of the single-peak microprotrusion 15 and the top is divided into a plurality of peaks. The shape of the multi-peak microprotrusions 15A and 15B, 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. 10), has a plurality of maximum points. The shape is approximated by an algebraic curve Z = a ₂ X ² + a ₄ X ⁴ +... + A _2n X ²ⁿ +.

  In such a multi-peak microprojection having a plurality of vertices, the hem portion is relatively thicker (periphery length is longer) with respect to the dimension in the vicinity of the vertex than the single-peak microprojection. Thereby, it can be said that the multimodal microprotrusions are superior in mechanical strength to the single-peak microprotrusions. Thereby, when there are multimodal microprotrusions having a plurality of vertices, the antireflection film 5 improves the scratch resistance as compared to the case of using only monomodal microprotrusions. Specifically, when external force is applied to the surface of the antireflection film 5, the external force is distributed and received at more vertices than when only single-peaked microprojections are used, so the external force applied to each vertex is reduced. In addition, it is possible to make it difficult for the microprotrusions to be damaged, thereby reducing the local deterioration of the antireflection function and further reducing the appearance defects. Moreover, even if a microprotrusion is damaged, the area of the damaged portion can be reduced. In addition, the multi-peak microprojections are higher than the multi-peak micro-projections and lower body parts than the multi-peak micro-projections by first receiving each external force and sacrificing damage. Prevents wear and tear of small microprojections. This also reduces local deterioration of the antireflection function and further reduces the occurrence of appearance defects.

  Further, when the antireflection film 5 having such a microprojection group (5, 5A, 5B,...) Including the multimodal microprojections 15A and 5B is examined in detail, the heights of the microprojections are variously different. (See FIG. 9). That is, when the heights of the microprotrusions are different in this way, for example, the large protrusions are damaged and other members come into contact with each other. The shape is maintained in the small protrusion having a small thickness. 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 minute projection group of the antireflection film 5 and the object, when the article slides relative to the antireflection article, the dust functions as an abrasive to form a minute projection ( 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 microprojections having a low height is weakened, the damage is reduced for the microprojections having a low height, and the antireflection performance is maintained by the microprojections having a low height remaining without being damaged or slightly damaged.

  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, it is possible to remarkably improve the slip as compared with a 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 height variation needs to be 10 nm or more when defined by the standard deviation. However, when it exceeds 50 nm, the surface roughness due to this variation can be felt. . Therefore, the height variation is preferably 10 nm or more and 50 nm or less.

  In addition, when multi-peaked microprotrusions are mixed in this way, the antireflection performance can be improved as compared with the case of using only single-peaked microprojections. That is, the multimodal microprotrusions 15A and 15B have higher light reflectivity than the single-peak microprotrusions even when the distance between adjacent protrusions is the same or when the protrusion height is the same. Will be reduced. The reason is that the multimodal microprotrusions 15A and 15B have a smaller change rate in the height direction of the effective refractive index in the vicinity of the apex than the monomodal microprotrusions having the same shape below the apex (the middle and the heel). Because of that.

That is, in FIG. 10, assuming that z = 0 is the height H = 0, and it is assumed that the microprojections 15, 15A, 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 15, 15 A,... Is n _M > 1, the total value of the sectional area of the surrounding medium (air) is S _A (z), and the minute protrusion 15. 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 considered on the basis of the monomodal microprotrusions 15, the multimodal microprotrusions 15A, 15B,... Are split in the vicinity of the top into a plurality of peaks. Therefore, in the virtual cutting plane Z = z that cuts the vicinity of the apex, the multimodal microprotrusions 15A, 15B,... Have a lower refractive index than the single-peak microprotrusions 15,. The ratio of the total cross-sectional area S _A (z) of the 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 more peripheral in the multimodal microprotrusions 15A, 15B,. It becomes close to the refractive index n _{A of the} 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, effective refractive index and surrounding unimodal microprojection When _{mono, |} a difference between the refractive index of the medium _{| n ef (z) -n a} (z)
| 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, in the vicinity of the top portion, the effective refractive index and the peripheral area of the microprojection group including the multimodal microprojections (including the peripheral medium between the microprojections) is smaller than that of the projection group including only the single-peak microprojections. The difference from the refractive index of the medium (air), 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 direction of the refractive index in the height direction. It can be seen that the continuity of change can be further increased.

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), for the microprojection group including the multimodal microprotrusions 15A, 15B,. The light reflectance is reduced as compared with the projection group consisting only of the projections 15.

  Even when a microprojection group consisting of only the single-peak microprojections 15 is used, it is sufficient to make the maximum value dmax of the distance between adjacent projections sufficiently small below the shortest wavelength λmin of the wavelength band of electromagnetic waves for preventing reflection. It is possible to exhibit an excellent 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 microprotrusion group consisting of multimodal microprotrusions 15A, 15B,..., The distance between adjacent protrusions d ^PEAK between the peaks near the top is the distance between adjacent protrusions of the microprotrusion main body from the heel to the middle It becomes smaller than 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 multimodal microprotrusions has a small ratio of the height of the ridges to the width of the buttock, and the ratio of the height of the apex to the width of the ridges of the unimodal microprojections is from 1/2 to It is about 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 stickiness and low reflectivity compared to the projection group composed of monomodal microprojections.

  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 described above, even when using materials that are more resistant to abrasion than conventional products and have low hardness due to process requirements, etc., 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 height of the minute protrusion can be about 50 μm. Similarly, in the infrared region around 700 nm, about 150 μm (about 400 μm in consideration of practical use). If possible. Note that, as described above, it is possible to find the manufacturing conditions that saturate the height of the arrangement pitch of the minute protrusions, 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.

  Furthermore, the antireflection function of the antireflection article depends not only on the interval between the microprojections but also on the aspect ratio, and when the aspect ratio is constant, for example, even when a sufficiently small reflectance can be secured in the visible light region, In the ultraviolet region, the reflectance increases compared to the visible light region, and the antireflection function is insufficient. In such a case, although it may be possible to set the pitch of the minute protrusions to be smaller so that sufficient antireflection function can be secured in the ultraviolet region, in this case, the height is insufficient in the infrared region. The reflectivity will increase. The aspect ratio is defined as H / W, which is a ratio obtained by dividing the height H of the minute protrusions by the diameter W (also referred to as width or thickness) at the bottom of the valley. Here, the diameter at the bottom of the valley coincides with the diameter (at the bottom) of the column if the shape of the microprotrusion near the bottom of the valley is a column. If the shape of the vicinity of the valley bottom of the microprojection is not a cylinder and the diameter of the bottom surface obtained by crossing the virtual plane connecting the valley bottom and the microprojection differs depending on the in-plane direction, the maximum value is set to the microprojection. Of the diameter. For example, when the bottom shape of the microprojection is an ellipse, the diameter is the major axis. In addition, when the bottom surface shape of the minute protrusion is a polygon, the diameter is the maximum diagonal length. In addition, when the width of the bottom of the valley (region consisting of the minimum point of the height) is smaller than the diameter and 20% or less, the average value (H / W) ave of the aspect ratio H / W of each microprotrusion is In terms of design, it can be substantially regarded as Have / dave.

  However, as in this embodiment, when unimodal microprotrusions and multimodal microprotrusions are mixed, an antireflection function equivalent to reducing the interval between adjacent protrusions by the multimodal microprotrusions is ensured. As a result, the reflectance can be reduced in a wide wavelength band, as in the case where unimodal micro-projections having different aspect ratios are mixed. In the case where a sufficiently small reflectance is ensured in a wide wavelength band centered on the visible light region, the multi-protrusion is small in the minute protrusions due to the distance between adjacent protrusions of 480 to 660 nm corresponding to the wavelength 480 to 660 nm in the visible light region. It is desirable to mix microprojections and unimodal microprojections.

  FIG. 11 is a photograph showing a plurality of minute protrusions at the apex, FIG. 11 (a) is based on AFM, and FIGS. 11 (b) and 11 (c) are based on SEM. In FIG. 11 (a), a groove g and a microprotrusion having three vertices and a microprotrusion having a groove g and two vertices can be seen, and in FIG. 11 (b), the groove g and four vertices are present. A microprotrusion and a microprojection having a groove g and two vertices can be seen, and in FIG. 11C, a microprotrusion having a groove g and three vertices, a microprojection having two vertices and a groove g can be seen. be able to.

[Large protrusions of large protrusions]
The microprotrusions 16A of the large protrusions 16 are created so that multi-peak microprotrusions and single-peak microprotrusions coexist with the same size as the microprotrusions 15 provided between the large protrusions 16 described above. Accordingly, even in the minute protrusion 16A, the interval between adjacent minute protrusions, the height, and the like are defined in the same manner as the minute protrusion 15 described above. The reference position of the height of the small protrusion 16A of the large protrusion 16 is an envelope surface connecting the valley bottoms between the small protrusions 16A.

  However, the large protrusions 16 function as spacers to prevent damage to the small protrusions 15 between the large protrusions 16, so that the small protrusions 16 </ b> A provided on the large protrusions 16 are the small protrusions 15 between the large protrusions 16. It is preferable to set so that the ratio of the multimodal microprotrusions is larger than that of.

[Configuration of each part]
In the antireflection film 5 (FIG. 2), the substrate 11 is made of cellulose resin such as TAC (Triacetylcellulose), acrylic resin such as PMMA (polymethyl methacrylate), or polyester resin such as PET (Polyethylene terephthalate). Various transparent resin films such as resins, polyolefin resins such as PP (polypropylene), vinyl resins such as PVC (polyvinyl chloride), and PC (polycarbonate) can be applied. Further, as described above, in the case where a fine uneven shape is formed on the transparent film material of the touch panel sensor film 4 and is manufactured integrally with the touch panel sensor film 4, the base material 11 is transparent applied to the touch panel sensor film 4. It is a film material.

  The antireflection film 5 is an uncured resin layer (resin layer (molding resin layer) subjected to a molding process) to be a fine uneven receiving layer on the base material 11. 17), and the receiving layer 17 is subjected to a molding process and hardened, whereby the microprotrusions 15 are arranged in close contact with the surface of the substrate 11. In this embodiment, an acrylate-based ultraviolet curable resin that is one of the resins for forming used for the forming process and is a hydrophilic resin is applied to the receiving layer 17, and the ultraviolet curable resin is applied on the substrate 11. The receiving layer 17 is formed by the layers.

  Thus, the antireflection film 5 thus prepared is arranged inside the image display device as in this embodiment by forming the microprojections and the large projections with an acrylate resin that is a hydrophilic resin. Even in this case, water droplets due to condensation can be stretched thinly to prevent clouding of the screen. Thereby, deterioration of visibility due to condensation can be effectively avoided.

〔Manufacturing process〕
FIG. 12 is a diagram illustrating a manufacturing process of the antireflection film 5. In this manufacturing process, the base material 11 is provided by a roll material. In the manufacturing process, an ultraviolet curable resin coating solution is applied to the substrate 11 by the die 22, and then the substrate 11 is pressed against the peripheral side surface of the roll plate 13 by the pressing roller 24. Here, the roll plate 23 is a mold for molding used for the molding process, and a fine shape corresponding to the fine surface shape of the antireflection film 5 is formed on the peripheral side surface. In this manufacturing process, the ultraviolet curable resin applied to the base material 11 is brought into close contact with the peripheral side surface of the roll plate 23, and the ultraviolet curable resin is sufficiently applied to the concave portions having fine irregularities formed on the peripheral side surface of the roll plate 23. Fill. In this manufacturing process, the ultraviolet curable resin is cured by irradiation with ultraviolet rays in this state, and thereby a microprojection group is produced on the surface of the substrate 11. In this manufacturing process, the substrate 11 is peeled off from the roll plate 23 through the peeling roller 25 together with the cured ultraviolet curable resin.

  FIG. 13 is a perspective view showing the configuration of the roll plate 23. The roll plate 23 has a fine concavo-convex shape formed on the peripheral side surface of the base material, which is a cylindrical or columnar metal material, by repeating anodization and etching, and the fine concavo-convex shape is as described above. Molded on the substrate 11. Here, the fine concavo-convex shape is formed by closely arranging a minute concave portion (fine hole) and a large concave portion corresponding to the fine protrusion 15 and the large protrusion, respectively. 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, although a cylindrical aluminum material is applied to the base material, a high-purity aluminum layer is directly or via various intermediate layers on a metal pipe made of stainless steel, copper, or the like. You may apply what provided.

  In the roll plate 23, 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 becomes larger 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 23 has a fine concavo-convex shape formed by closely arranging a small concave portion and a large concave portion respectively corresponding to the small protrusion and the large protrusion of the antireflection film 5.

[Pre-processing treatment, anodizing treatment, etching treatment]
FIG. 14 is a diagram illustrating a manufacturing process of the roll plate 23. In this manufacturing process, a pilot hole used for creating a large protrusion is created at a location corresponding to the large protrusion 16 by a cutting process using a drill or by irradiation with a laser beam (for example, a wavelength of 532 nm) in the pre-processing process. . In addition, as a method for creating the prepared hole, various methods such as thermal processing by an ablation can be widely applied instead.

  Subsequently, 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 in which electrolytic elution action and abrasion action by abrasive grains are combined (electropolishing). Subsequently, in this step, the base material is processed by alternately repeating the anodic oxidation steps A1,..., AN, etching steps E1,.

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

  In the subsequent etching process E1,..., EN, the mold is immersed in an etching solution, the hole diameter of the fine hole produced and dug in the anodizing process A1,. These fine holes are shaped so that the hole diameter becomes smaller and smoother. As the etching solution, various etching solutions that are applied to this type of treatment can be widely applied. More specifically, for example, a sulfuric acid aqueous solution, an oxalic acid aqueous solution, a phosphoric acid aqueous solution, or the like can be used. Note that the same solution as the solution used for the anodic oxidation treatment may be used without applying a voltage so that the solution can be used also as an etching solution. 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 controlling the applied voltage in the repeated anodic oxidation in this way, the roll plate 23 is created so that single-peak microprojections and multi-peak microprojections are mixed, and the height of the microprotrusions is further increased. Controls the distribution of thickness. The antireflection article can control, for example, the characteristics in the viewing angle direction that performs the antireflection function by controlling the height distribution of the microprojections.

  In addition, after preparing a pilot hole in advance, anodizing treatment and etching process are repeated to create a micro hole corresponding to the micro projection in this pilot hole, thereby creating a large recess corresponding to the large projection. The large protrusion 16 can be formed integrally with the minute protrusion 15.

  As a result, in this embodiment, the roll plate is formed with a minute recess corresponding to the minute protrusion and a large recess corresponding to the large protrusion having a large shape with respect to the minute protrusion, and the large recess is formed by discrete random arrangement. The depth is deeper than the minute recesses, and the surface side is made wider than the longest wavelength of the wavelength band for preventing reflection. The minute recesses related to the minute protrusions are arranged closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection between the large-sized recesses.

[Control of height distribution]
Here, when the fine holes are produced by anodizing treatment, the applied voltage at the time of anodizing and the pitch of the fine holes are in a proportional relationship. Thus, if the applied voltage of the anodizing process is varied in the repetition of the anodizing process and the etching process in this way, it is possible to control the ratio by mixing fine holes with different digging times in the depth direction. This makes it possible to control the height distribution of the microprojections.

  In addition, in the case where the applied voltage in the anodizing process is varied in this way, a plurality of fine holes may be formed on the bottom surface of a fine hole having a large thickness to form a fine hole related to a multimodal microprojection. It is possible to control the distribution of the height of the multi-modal microprotrusions by controlling the height of the fine hole having a large thickness and controlling the depth of the microhole formed on the bottom surface.

  FIG. 15 is a schematic diagram for explaining the control of such a height distribution, and is a diagram showing fine holes produced by an anodizing step and an etching step in the manufacturing process of the shaping mold. There is a proportional relationship between the applied voltage of the anodizing treatment and the pitch of the fine holes to be produced. In practice, however, the pitch of the fine holes varies depending on the grain boundaries of aluminum used for processing. However, in FIG. 15, it is assumed that there are no such variations, and that the fine holes are produced by regular arrangement. FIGS. 15A to 15E are a plan view of a fine hole produced in each step and a corresponding cross-sectional view taken along line aa.

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

  Subsequently, in this embodiment, the second anodic oxidation process is performed with the applied voltage V2 (V2> V1) higher than that during the first anodic oxidation, and then the etching process is performed (hereinafter referred to as a second process as appropriate). ). Here, in this case, as shown in FIG. 15 (b), the applied voltage related to the second anodizing treatment among the fine holes f1 produced by the first anodizing treatment by increasing the applied voltage. Only the fine hole corresponding to the voltage is dug in the depth direction (indicated by reference numeral f2) and etched. Accordingly, if the applied voltage is varied in two steps, for example, fine holes having different depth distributions can be mixed in the second step.

  Subsequently, in this embodiment, the third anodic oxidation process is performed with the applied voltage V3 (V3> V2) higher than that during the second anodic oxidation, and then the etching process is performed (hereinafter referred to as a third process as appropriate). (FIG. 15 (c)). Here, the third step is a step for producing fine holes having different pitches. Therefore, in this step, the applied voltage is gradually increased from the applied voltage V2 in the second anodic oxidation step. Here, when the increase in the applied voltage is executed discretely (stepwise), the height distribution of the microprotrusions can be set discretely, and microholes having different depth distributions can be mixed. Further, when the increase in the applied voltage is continuously changed, the depth distribution can be set to a normal distribution.

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

  Subsequently, in this embodiment, after performing the fourth anodic oxidation process with the applied voltage V4 (V4> V3) higher than that in the third anodic oxidation, the etching process is performed (hereinafter, referred to as a fourth process as appropriate). (FIG. 15 (d)). Here, the fourth step is a step for producing a fine hole with a pitch according to a target interprotrusion interval, and the applied voltage V4 is a voltage corresponding to this pitch. In this fourth step, by gradually increasing the applied voltage, a part of the fine holes dug greatly by the third step is further dug further, and the dug fine holes are made unimodal. A minute hole f4 corresponding to the minute protrusion is formed.

  Subsequently, in this embodiment, the fifth anodic oxidation process is performed by the applied voltage V1 in the first process, and then the etching process is performed (FIG. 15E). Here, in the fifth step, a fine hole whose bottom surface is flattened by the third step and is not affected by the anodizing treatment of the fourth step, a fine hole is formed on the bottom surface. A plurality of microholes f5 for multi-peak protrusions are formed. Here, by adjusting the magnitude of the applied voltage V1 in the fifth step, the number of fine holes f5 formed on the bottom surface can be increased or decreased.

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

  16 and 17 are diagrams showing the distribution of the heights of the fine protrusions produced using the roll plate produced by the first to fifth steps.

  FIG. 16 shows the case where the applied voltage of the anodic oxidation process is continuously changed in the second process, the third process, and the fourth process. In the fourth process, the applied voltage is decreased from the applied voltage of the third process. It has been made. In the antireflection article shown in FIG. 16, the height distribution of the microprojections shows a normal distribution, and the antireflection article is good in a relatively narrow range centered on the vertical line of the surface on which the microprojections are formed. The prevention function can be secured. Also, at this time, in such a height distribution, the multimodal microprojections (two and three vertices are indicated by two peaks and three peaks, respectively) also have a normal distribution in which the average values of the heights are almost the same. This makes it possible to efficiently exhibit the scratch resistance function of multimodal microprotrusions, and to reduce the reflectivity sufficiently in a wide wavelength band centered on the visible light range. It is possible to improve the function of characteristics.

  In the example of FIG. 16, the average value m of the height h of the microprojections was 145.7 nm, and the standard deviation δ thereof was 22.1 nm. Further, when the average value m and standard deviation δ define h <m−σ for the low altitude region, m−σ ≦ h ≦ m + σ for the medium altitude region, and h> m + σ for the high altitude region, the total number Nt (263) Among these microprotrusions, multimodal microprotrusions have distributions of 2, 23, and 5 in the medium altitude region, medium altitude region, and high altitude region, respectively. It can be seen that the height distribution is the same as that of the entire microprojection.

  FIG. 17 illustrates the first to fifth steps described above. In the second step, the voltage is increased stepwise to execute the processing of the third step. In the fourth step, the example of FIG. A deep hole having a deep depth is produced by performing an anodic oxidation process at a voltage higher than the maximum voltage, and the fifth step is repeated twice corresponding to the fourth step.

  In the example of FIG. 17, a frequency distribution is obtained by an amphoteric characteristic having distribution peaks on the high side and the low side, and the distribution of microprojections having a high height can be increased. A distribution of multimodal microprojections can be formed corresponding to the distribution. As a result, the optical characteristics from the oblique direction can be improved and the wide viewing angle characteristics can be improved. Further, the reflectance can be sufficiently lowered in a wide wavelength band centered on the visible light region.

[Effects of First Embodiment]
According to this embodiment, the scratch resistance can be improved by providing a large protrusion having a shape larger than that of the minute protrusion and having the minute protrusion on the top. In particular, this large protrusion can function as a spacer, so that when placed on the exit surface side of the image display panel to improve visibility and light utilization efficiency, other members on this exit surface side It is possible to effectively avoid damage to the microprojections due to contact with the surface, thereby effectively avoiding accidents such as local wear of the microprojections and adhesion of the antireflection article to the contact object. it can.

At this time, by arranging the large protrusions at a density of 1 piece / cm ² or more and 30 pieces / cm ² or less, it is ensured that the antireflection function is not impaired and the deterioration of the image quality is not perceived. It is possible to prevent contact of the members. In addition, since the large protrusion has a height of 1 μm or more and 100 μm or less, the contact of other members can be surely prevented without impairing the antireflection function and without perceiving image quality deterioration. be able to. Furthermore, the large protrusions can be easily and reliably manufactured in a desired size by various manufacturing methods.

  In addition, the large protrusion has a base portion width of 5 μm or more and 30 μm or less, so that it is possible to reliably prevent contact with other members without impairing the antireflection function or perceiving image quality deterioration. can do. Furthermore, the large protrusions can be easily and reliably manufactured in a desired size by various manufacturing methods.

  Also, the large protrusions can be made even less conspicuous by arranging the large protrusions at a location overlapping the black matrix that is the light shielding portion of the image display panel. In addition, after preparing a pilot hole corresponding to a large protrusion by pre-processing, a roll plate is prepared by forming a minute recess corresponding to the minute protrusion between the pilot holes and the pilot hole by repeating anodizing treatment and etching process. Thus, a large protrusion can be formed integrally with the fine protrusion, and an antireflection film having the large protrusion can be formed by a simple process.

[Second Embodiment]
When the anti-reflection film is produced by transferring the fine uneven shape produced on the peripheral side surface of the roll plate as described above, the fine uneven shape of the roll plate may be locally damaged, As a result, there may be a case where a defect portion where the fine protrusions 15 are not normally formed on the antireflection article is generated. Therefore, in this embodiment, when a defect exists within the range of the arrangement density described above, the large protrusion 16 is provided at the defective portion, and thereby the large protrusion 16 is disposed by effectively utilizing the defective portion.

  In addition, from this, in this embodiment, when arrange | positioning the large processus | protrusion 16 with the arrangement | positioning density mentioned above, the antireflection film 5 by the rectangular area | region by the area (reciprocal number of arrangement density) allocated to one of the large processus | protrusions 16 is provided. Are divided (see FIG. 4), and one large protrusion 16 is arranged in each divided region. At the time of this arrangement, in a region where a defect exists, the large protrusion 16 is arranged at the position of the defect. In addition, when there are a plurality of defects, a large protrusion is arranged on the side of a large-shaped defect. On the other hand, when there is no defect, the large protrusions 16 are arranged on the black matrix BM at random positions in the region.

  Further, in this embodiment, a large protrusion is created by post-processing. FIG. 18 is a flowchart showing manufacturing steps of the antireflection film according to the second embodiment of the present invention. In this embodiment, after forming the receiving layer (molding resin layer) by applying an ultraviolet curable resin to the surface of the base material 11 in the molding resin layer creation step SP2, the roll plate is formed in the molding step SP3. By the used forming process, the fine uneven shape produced on the peripheral side surface of the roll plate is transferred. Here, in this embodiment, this roll plate is formed with only minute recesses corresponding to the minute protrusions on the peripheral side surface, whereby in this embodiment, only the minute protrusions are densely formed on the surface of the substrate 11 first. create.

  Subsequently, the manufacturing process creates a large protrusion in the large protrusion manufacturing process SP4. Here, in this manufacturing process, an acrylate-based ultraviolet curable resin is dropped by a dispenser onto a predetermined place and dried, and then semi-cured by local ultraviolet irradiation, thereby producing a large protrusion. Create a foundation for Subsequently, a fine projection is created on the top of the base by a molding process using a molding die having a recess corresponding to the fine projection, thereby creating a large projection.

  In this embodiment, although the large protrusion is created by post-processing after the minute protrusion is created, the first embodiment is combined with the manufacturing method for creating the large protrusion by processing the shaping mold described above. Thus, a large protrusion produced from a roll plate and a large protrusion produced by post-processing of the antireflection film may be mixed.

  As in this embodiment, the same effect as in the first embodiment can be obtained even if a large protrusion is formed by post-processing after forming a minute protrusion. Also, in this case, by creating a large projection by post-processing after creating a microprojection, for example, when a defect occurs later, the creation location of the large projection can be changed to the location of this defect, or the same It is possible to flexibly deal with the arrangement of large protrusions, such as creating anti-reflection films with different large protrusion density using roll plates, and changing the size of large protrusions, and as a result, productivity Can be improved.

  In addition, by providing a large protrusion at the defective portion, the large protrusion can be arranged by effectively using the defective portion.

[Third Embodiment]
19 and 20 are views showing an antireflection film according to the third embodiment of the present invention in comparison with FIGS. 2 and 3. This embodiment has the same configuration as that of the first embodiment or the second embodiment except that the configuration of the antireflection film is different.

  Here, the antireflection film of this embodiment is further provided with a second large protrusion 27 in addition to the minute protrusion 15 and the large protrusion 16. The second large protrusion 27 is formed in a substantially circular shape when viewed in plan, and is formed in a conical shape with a rounded top, a truncated cone shape with a flat top, a semicircular shape, or the like. As a result, the antireflection film of this embodiment causes the second large protrusions 27 to function as spacers, effectively avoiding damage to the small protrusions 16A provided on the small protrusions 15 and 16 and further improving scratch resistance. Improve sexiness.

For this reason, the second large protrusions 27 are produced with the same size as the large protrusions 16 or a larger shape than the large protrusions 16. As a result, the second large protrusion 27 is produced with a height H ₂₇ of 5 μm or more and 100 μm or less. In addition, the width D _{27 of the} base portion is 5 μm or more and 30 μm or less.

Similarly to the large protrusions 16, they are produced at a density of 1 piece / cm ² or more and 30 pieces / cm ² or less by discrete random arrangement. Moreover, like the large protrusion 16, it arrange | positions so that it may overlap with a black matrix, and also arrange | positions in the site | part of a defect.

  The second large protrusions 27 are formed simultaneously with the large protrusions 16 or separately from the large protrusions 16 by the same production method as the large protrusions 16 described above for the first and second embodiments.

  As in this embodiment, by further providing a second large protrusion and allowing the second large protrusion to function as a spacer, the scratch resistance can be further improved.

[Fourth Embodiment]
In this embodiment, the large protrusions 16 and / or the second large protrusions 27 are formed by a so-called stamping technique. This embodiment is configured in the same manner as the above-described first to third embodiments except that the configuration related to the shaping process is different.

  That is, in this embodiment, a mold for molding is prepared by forming a recess corresponding to the large protrusion 16 and / or a recess corresponding to the second large protrusion 27, and an ultraviolet curable resin is dispensed into the recess by a dispenser. Dripping. After that, the UV curable resin is dried and semi-cured, and the molding die is pressed against the surface on which the fine projections are formed in this state to irradiate ultraviolet rays, thereby forming the concave portion formed in the molding die. The large protrusions 16 and / or the second large protrusions 27 having the shape shown in FIG.

  Even if the large protrusions 16 and / or the second large protrusions 27 are formed by a stamping method as in this embodiment, the same effects as in the above-described embodiment can be obtained.

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

  That is, in the above-described embodiment, the case where the antireflection film is disposed between the emission surface of the image display panel and the touch panel sensor film is described. However, the present invention is not limited thereto, and is provided inside the touch panel sensor film. In this case, the present invention can be widely applied to a case where an antireflection film is provided on another member disposed on the exit surface of the image display panel.

  Specifically, when it is placed inside the sensor film for a touch panel, a microprojection group is formed on a substrate made of a transparent film, and an electrode such as ITO (indium tin oxide) is formed on the microprojection group to form an electrode film. In the case of producing a large protrusion, a large protrusion is mixed in the minute protrusion group. The sensor film for the touch panel is made by laminating this electrode film, so that the visibility and light utilization efficiency are improved by the minute projections, and the large projections function as spacers by pressing with a finger or the like. The microprojections of the electrode film can be prevented from being damaged. As another member disposed on the exit surface of the image display panel, for example, an optical film that corrects viewing angle characteristics can be exemplified.

  In the above-described embodiment, the case where the antireflection film is disposed on the exit surface side of the image display panel has been described. However, the present invention is not limited to this, and the visibility and light utilization efficiency are improved by placing the image display panel on the entrance surface side. It can be widely applied to the improvement. Specifically, when light reflection on the image display panel is reduced by being arranged on the incident surface of the image display panel, it is arranged on the emission surface of the backlight device to reduce light reflection on this emission surface. Can be applied in case. In addition, when arrange | positioning on the entrance plane of an image display panel, you may make it hold | maintain by sticking to the entrance plane of an image display panel by producing an antireflection film separately, and also the entrance plane side of an image display panel. You may produce integrally to a member (in this case, it is a base material of a linearly-polarizing plate). Moreover, when arrange | positioning on the output surface of a backlight apparatus, you may make it produce an antireflection film separately and affix it on the output surface of a backlight apparatus, or the optical film ( For example, a prism sheet for correcting directivity may be integrally formed.

  In the above-described embodiment, the case where the antireflection film is disposed inside the image display device has been described. However, the present invention is not limited thereto, and the image display device may be disposed on the outermost surface of the image display device. In this case, for example, it is possible to reduce damage to the microprojections due to contact with a finger or the like. In this case, it is preferable to provide a water-repellent resin layer on the surface of the antireflection film by a water-repellent treatment. By providing the water-repellent resin layer, it is possible to ensure water repellency and make it difficult for dirt to adhere. . Such a water-repellent resin layer can be prepared by coating with a coating method such as roll coating, gravure coating, knife coating, dip coating, spray coating, etc., using a resin composition containing a fluorine resin, for example. it can.

  Moreover, although the case where this invention is applied to the antireflection film which is an antireflection article by a film shape was described in the above-mentioned embodiment, this invention is not limited to this, The shape of an antireflection article is a flat film shape. However, the flat sheet shape and the flat plate shape (referred to as a film, a sheet, and a plate in the order of relatively thin thicknesses) can be used instead of the flat shape. A film shape, a sheet shape, and a plate shape can be used, and three-dimensional shapes such as various lenses and various prisms can be appropriately employed depending on the application.

  In these cases, the substrate 11 is made of, for example, glass such as soda glass, potassium glass, lead glass, ceramics such as PLZT, quartz, meteorite, in addition to sheet material and plate material, depending on the shape of the antireflection article. Various transparent inorganic materials such as can be applied, and further, an opaque organic material can be applied.

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

  In the above-described embodiment, as described above with reference to FIG. 2, the microprojections 15, 15 </ b> A, 15 </ b> B,... Are formed on the receptor layer 17 formed on one surface of the base material 11, and the receptor layer is formed. 17 is cured to form an antireflection article, and an antireflection film is constituted by a two-layer structure of a base material and a receiving layer. However, the present invention is not limited to such a form. The antireflection article of the present invention may have a single-layer configuration in which the minute protrusion groups 15, 15A, 15B,... Are directly formed on one surface of the substrate 11 without interposing another layer. . Further, one or more intermediate layers (layers for improving substrate surface performance such as interlayer adhesion, coating suitability, surface smoothness, etc. on one surface of the substrate 11 are also referred to as a primer layer, an anchor layer, and the like. ) To form a receiving layer 17 and the surface of the receiving layer may be composed of three or more layers formed with microprojections 15, 15A, 15B,.

  Further, in the above-described embodiment, as shown in FIG. 2, the minute protrusion groups 15, 15 </ b> A, 15 </ b> B,... Are formed only on one surface of the base material 11. Not done. The present invention can be widely applied to the case where the microprojection groups 15, 15A, 15B,... Are formed on both surfaces of the substrate 11 (directly or via other layers).

  In the above-described embodiment, as shown in FIG. 2, the surface connecting the valley bottoms (minimum points of height) between adjacent minute protrusions is a flat surface having a constant height. Not limited to this, as shown in FIG. 21, the envelope surface connecting the valley bottoms between the microprotrusions may be undulated with a period D (that is, D> λmax) equal to or longer than the longest wavelength λmax of the visible light band. Further, the periodic undulation is only in one direction (for example, the X direction) on the XY plane (see FIG. 21) parallel to the front and back surfaces of the base material 11 and at a constant height in the direction (for example, the Y direction). There may be waviness or both directions in the XY plane (X direction and Y direction) may have undulations. The uneven surface 20 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.

  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 producing an antireflection article by processing a sheet using a flat plate, a mold for shaping with a specific curved surface shape, etc. It can change suitably according to the shape of the transparent base material which concerns on a shape.

  Moreover, although the above-mentioned embodiment described the case where the anti-reflective article by an anti-reflective film is arrange | positioned to an image display panel, this invention is applicable not only to this but to various uses. Specifically, on the glass plate surface (external side) used for the shop show window and product display box, the exhibition window and display box of art museum exhibits, or both the front and back surfaces (product or exhibit side) It may be arranged. 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, in the visible light band (380 to 780 nm), an antireflection effect cannot be expected, and an antireflection article exhibiting an antireflection effect for infrared rays having a wavelength of 850 nm or more can be obtained.

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

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Image display panel 3 Backlight apparatus 4 Sensor film for touchscreens 5, 5A Antireflection film 11 Base material 15, 15A, 15B, 16A Microprotrusion 16 Large protrusion 17 Receiving layer, shaping resin layer 20 Uneven surface 22 Die 23 Roll plate 24, 25 Roller 27 Second large protrusion BM Black matrix g Groove

Claims (11)

In the anti-reflective article aiming at anti-reflection by the fine uneven shape of the surface,
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Anti-reflective article with minute protrusions. The large protrusion is
The antireflection article according to claim 1, wherein the antireflection article is arranged at a density of 1 piece / cm ² or more and 30 pieces / cm ² or less. The large protrusion is
The antireflection article according to claim 1, wherein the height is 1 μm or more and 100 μm or less. The large protrusion is
The width | variety of a base part is 5 micrometers or more and 30 micrometers or less. The reflection preventing article in any one of Claim 1, Claim 2, and Claim 3. The large protrusion is
The antireflection article according to any one of claims 1, 2, 3, and 4, wherein the antireflective article is produced at a position of a defect related to a minute protrusion between the large protrusions. The anti-reflective article is
It is a film shape and is arranged on the exit surface side of the image display panel.
The large protrusion is
When arranged on the output surface side of the image display panel, the image display panel is arranged at a location overlapping with a light shielding portion between pixels of the image display panel. The antireflection article according to any one of the above. The antireflection article according to any one of claims 1, 2, 3, 4, 5, and 6 is disposed on an emission surface side and / or an incident surface side of an image display panel. Image display device. In the method of manufacturing an antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The method of manufacturing the antireflection article includes:
On the surface of the substrate, a molding resin layer creating step for creating a molding resin layer,
A molding step of creating the microprotrusions on the base material by a molding process of the molding resin layer using a molding die; and
A method for producing an antireflection article, comprising: a large protrusion forming step for forming the large protrusion on a surface of the base material on which the micro protrusion is formed. In the method of manufacturing an antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The method of manufacturing the antireflection article includes:
On the surface of the base material, a pretreatment process for creating a pilot hole related to the large protrusion,
By repeating the anodizing process and the etching process, a minute recess corresponding to the minute protrusion between the large protrusions is formed between the pilot holes, and corresponding to the minute protrusion provided on the large protrusion in the pilot hole. By creating a recess, a recess creating step of creating a molding die by creating a large recess corresponding to the large projection,
On the surface of the substrate, a molding resin layer creating step for creating a molding resin layer,
A method for manufacturing an antireflection article, comprising: a molding step of creating the microprojections and the large projections on the base material by a molding process of the molding resin layer using the molding die. In the mold for shaping the antireflection article used for the production of the antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The mold for molding is
A minute recess corresponding to the minute protrusion and a large recess corresponding to the large protrusion are created,
The large recess is
Made by discrete random arrangement,
The depth is deeper than the minute recess, and the surface side is wider than the longest wavelength of the wavelength band for preventing reflection,
The minute recess is
A mold for shaping an antireflection article, which is disposed between the large concave portions more closely than the shortest wavelength of the wavelength band of electromagnetic waves for preventing reflection. In the manufacturing method of the molding die used for the production of the antireflection article,
The antireflective article is
Large protrusions are arranged on the surface by discrete random arrangements,
Between the large protrusions, the minute protrusions are disposed closer to each other than the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection,
The large protrusion is
The height of the small protrusions between the large protrusions is higher and the base part is wider than the longest wavelength of the wavelength band for preventing reflection, and at least the apex is closer to the shortest wavelength of the wavelength band of the electromagnetic wave for preventing reflection. Microprojections are arranged,
The method for producing the mold for molding is as follows:
On the surface of the base material, a pretreatment process for creating a pilot hole related to the large protrusion,
By repeating the anodizing process and the etching process, a minute recess corresponding to the minute protrusion between the large protrusions is formed between the pilot holes, and corresponding to the minute protrusion provided on the large protrusion in the pilot hole. A method for manufacturing a molding die, comprising: a recess creating step of creating a recess and creating a large recess corresponding to the large protrusion.