WO2001071394A1

WO2001071394A1 - Antireflection product and production method therefor

Info

Publication number: WO2001071394A1
Application number: PCT/JP2001/002234
Authority: WO
Inventors: Shinji Kondoh; Takuji Oyama; Takashige Yoneda
Original assignee: Asahi Glass Company, Limited
Priority date: 2000-03-21
Filing date: 2001-03-21
Publication date: 2001-09-27

Abstract

An antireflection product having on a substrate an optical thin film which is formed by removing columnar phases from a composite film consisting of many one-dimensionally grown columnar phases and matrix phases surrounding the former, and in which are formed many pores continuing from one surface to the other of the film, surrounded by walls consisting of the matrix phases, and one-dimensionally penetrating, characterized in that the refractive index of the optical thin film is lower than that of the substrate and between that of the matrix phases and one, whereby providing the antireflection product low in reflective index, high in film strength, and excellent in adhesiveness to the substrate; and a production method therefor.

Description

Description Anti-reflective article and method of manufacturing the same

Technical field

The present invention relates to an antireflection article having an optical thin film having one-dimensionally penetrated pores (hereinafter, also referred to as one-dimensionally penetrated pores). The optical thin film of the present invention is suitable for a front glass of a display, a windshield of a vehicle, a window glass of a building, an antireflection film used for a mirror, an optical lens, and the like, and has excellent durability. Background art

Glass is used for the display of personal computers and computers, but if a normal glass surface is used, several percent of the light incident on the screen is reflected, so fluorescent lights and surrounding scenery are reflected on the screen and displayed. There was a problem that the contents were hard to see. Similar phenomena are also a problem for architectural and architectural glass such as picture frame glass and show window glass.

Further, optical members such as solar cells, cover glasses for solar water heaters, glasses, and cameras preferably have low reflectivity in order to maximize their performance.

It is preferable that windshields used for automobiles and railway vehicles have high transmission performance and low reflection performance in order to reduce glare and glare during nighttime driving and to assist safe operation. Materials that have both high transmission performance and low reflection performance are required in a wide range of fields, not only for glass but also for plastics. By the way, when used in a relatively harsh environment such as a windshield of a vehicle, not only low reflection performance but also durability for maintaining the performance for a long time is required at the same time. Conventionally, in order to obtain highly transmissive glass or plastic by suppressing surface reflection, a film having low reflectivity on the surface of glass or plastic (for example, a single-layer low refractive index film or low refractive index film) Surface coating of an optical multilayer film in which layers and high-refractive-index layers are alternately stacked), and antireflection treatment has been performed using optical interference. In order to reduce the reflectance over a wide wavelength range of visible light, the latter optical multilayer is desirable. Preferably, this method requires two or three or more films having different compositions to be stacked. In addition, in order to obtain a low refractive index with a single-layer film, it is necessary to select a highly durable material that has a lower refractive index than glass and plastics, and is excellent in abrasion resistance, chemical resistance or moisture resistance. There is. However, there has been no material that can simultaneously satisfy these performances.

For example, as the material of lower refractive index than the Soviet one da-lime glass generally used frequently (refractive index 1. 52), Mg F ₂ (refractive index 1.2 2) or A 1 ₂ F ₃ (refractive index 1. 36), etc. However, any fluoride also withstand moisture as compared with the oxide material such as S I_〇 _2, inferior in terms of oxidation resistance, much as a coating material to the glass surface durability is required not being used.

Further, in addition to the inorganic film, a polymer film having a fluorinated aliphatic ring structure using a cured film obtained by curing an acrylic copolymer together with a cross-linking material as an underlayer (Japanese Patent Application Laid-Open No. H02-019801) A low-reflection multilayer film obtained by forming a film has been studied (JP-A-5-254703). This multilayer film has no problem in adhesion to the substrate when the substrate is plastics, but does not provide sufficient adhesion strength when the substrate is glass.

On the other hand, there has been a technique for forming a film such as an oxide on a surface of glass or plastics with good adhesion. For example, Si ₂ (refractive index of a dense body of 1.44 to 1.47) can be formed on the substrate with good adhesion by a sputtering method or a sol-gel method.

However, the film formed by the above method is a dense film, and the refractive index is not so different from that of the base glass (for example, the refractive index of soda lime glass is 1.52), so that the low reflection performance is not practically sufficient. . Therefore, an attempt to lower the refractive index of sufficiently introduce small pore membrane than the wavelength of light in the film, such as S I_〇 ₂ in some way have been made.

Several methods have been proposed for obtaining a low refractive index film by introducing pores into the film that are about the same as or smaller than the wavelength of light. For example, after a borosilicate glass substrate is decomposed by spinodal, it is etched with a mixed solution of ammonium fluoride and a solution of hydrofluoric acid and nitric acid, and only the surface is made porous to provide a low refractive index layer. (J. Opt. Soc. Amer., 66, 515 (19776)) is known, but in this case, the usable substrate is limited to borosilicate glass.

Another method is to prepare a ceramic rally containing fine powders such as silica and alumina, apply the slurry to the surface of glass or plastics using a dipping method or a Doc Yuichi blade method, and then heat, dry, or sinter. There is known a method of forming a porous inorganic film by using the method. However, increasing the porosity to lower the refractive index often causes inconsistent characteristics in that the strength of the film itself and the adhesion strength between the film and the substrate are reduced.

An object of the present invention is to provide an anti-reflection article which solves the above-mentioned disadvantages of the prior art, has a low refractive index, has a high film strength, and has excellent adhesion to a substrate.

The present invention also provides a method for manufacturing an anti-reflective article capable of manufacturing the anti-reflective article without restriction on a substrate. Disclosure of the invention

The present invention is formed by removing a one-dimensionally grown columnar phase in a composite film composed of a number of one-dimensionally grown columnar phases and a matrix phase surrounding the columnar phase on a substrate. An antireflection article on which an optical thin film having a large number of one-dimensionally penetrating pores surrounded by a continuous wall from one surface to the other surface of the film is formed, wherein the refractive index of the optical thin film is An anti-reflection article characterized by having a refractive index smaller than the refractive index of the substrate and between 1 and 1 of the material constituting the optical thin film.

The refractive index in the present invention means the refractive index at a wavelength of 550 nm. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic view showing a procedure for forming an optical thin film of the present invention. Explanation of reference numerals

1: Substrate

2: Columnar phase 3: Matrix phase

4: Composite membrane

5: Optical thin film

6: Amorphous precursor film Best mode for carrying out the invention

The optical thin film according to the present invention is an optical thin film having a large number of one-dimensionally penetrated pores surrounded by a continuous wall from one surface to the other surface of the film. It has a refractive index between the value of the refractive index of the constituent material (dense body) and 1, and has a refractive index according to its porosity.

Assuming that the porosity is R and the refractive index of the matrix phase (dense body) is n, the refractive index of air is 1, so the refractive index N of the optical thin film having one-dimensional through-pores is N n X (1 -R) + 1 XR, which can be roughly expressed as

In the present invention, from the viewpoint of imparting antireflection performance, the refractive index of the optical thin film is set to be smaller than the refractive index of the substrate.

The optical thin film preferably has a thickness of 60 to 200 nm. If it is less than 60 nm, it is difficult to obtain sufficiently low reflection characteristics, and the strength of the film tends to be insufficient. On the other hand, if it exceeds 200 nm, it is difficult to obtain low reflection characteristics in a wide wavelength range, and the film tends to peel off. For example, if the film thickness is 50 nm, the low reflection characteristics in the visible light region are not sufficient, and the film strength is not sufficient.If the film thickness is 250 nm, the reflection cannot be suppressed over a wide range, and In some cases, peeling occurred partially in the subsequent drying process.

In the present invention, the ratio (dZr) of the average pore diameter (r) of the pores to the average thickness (d) of the wall is preferably 0.10.3. If it is less than 0.1, the strength of the film decreases, and if it exceeds 0.3, it is difficult to obtain sufficient low reflection characteristics.

The optical thin film of the present invention is composed of at least one selected from the group consisting of oxides, carbides, nitrides, borides and fluorides, and is selected according to the intended use. Oxides are most preferred from the viewpoints of stability, ease of formation, and the like. The average diameter of the one-dimensional through-pores is preferably 1500 nm. 1 nm If it is less than 1, the one-dimensionally extending phase lacks continuity and often remains in the matrix phase without being removed after etching described later. If the phase to be removed remains, problems such as metallic reflection and coloring often occur. In addition, if the average pore diameter exceeds 500 nm, large pores (about 500 to 1000 nm in diameter) exist after etching. This often causes haze (milky white turbidity due to light scattering by large holes). The average pore size is particularly preferably from 1 to 100 nm.

According to the present invention, by appropriately selecting a material and a porosity, a film having both durability and a low refractive index can be obtained, and an antireflection article having only one optical thin film formed on a substrate can be obtained. Can also be provided.

For example, materials with high durability but not sufficiently low refractive index, such as titania, silica, alumina, zirconia, silicon nitride, aluminum nitride, tin oxide, zinc oxide, and tungsten oxide If an optical thin film is formed using materials such as nickel oxide, indium-tin oxide (ITO), etc., both durability and a low refractive index can be satisfied with only one layer.

Further, a multilayer film can be formed by combining the optical thin film of the present invention with another film. For example, the optical thin film can be used as one of multilayer films such as a multilayer antireflection film, a multilayer heat ray reflection film, and a multilayer conductive film.

As a multilayer anti-reflection film, λ is the wavelength of light to be anti-reflective. 1) From the substrate side, the high refractive index layer and the low refractive index layer have an optical thickness of λ / 2—λΖ, 4 (or; 2) Antireflection film of 2 layers formed by λ / 4), 2) From the substrate side, a medium refractive index layer, a high refractive index layer and a low refractive index layer were formed with optical thickness λΖ4—λ / 2—λΖ4. 3) From the side of the substrate, 4 layers with low refractive index layer, middle refractive index layer, high refractive index layer, and low refractive index layer formed with an optical thickness of λΖ4—λ / 2—λΖ2-4. Are known as typical examples. The optical thin film is suitable as a low refractive index layer of these multilayer antireflection films.

In addition, a two-layer light-absorbing antireflection body called a substrate light-absorbing film and a low-refractive-index film is also known (Japanese Patent Application Laid-Open Nos. 9-1156964 and 10-96801) Etc.). The optical thin film can also be used for the low refractive index film of the light absorbing antireflective body. In the antireflection article of the present invention, the reflectance of the optical thin film with respect to incident light from the film side (opposite to the film side) The reflectance of only the film side surface excluding the reflection by the surface on the side (hereinafter also referred to as the film surface reflectance) is less than the reflectance of a substrate (blank) without an optical thin film at 15 ° incident light. Is preferably reduced by 40% or more (especially 60% or more). In the case of an article on which a multilayer film having the optical thin film is formed, the reflection spectrum of the optical thin film with respect to the incident light of 15 ° from the film side (only the film-side surface excluding the reflection by the surface opposite to the film side) is used. The reflectance is preferably 1% or less in a wavelength region of 400 to 700 nm. In the case of laminated glass in which glass with an optical thin film is laminated with another glass via an intermediate film, the film surface reflectance of 60 ° incident light is 4% less than the reflectance when there is no optical thin film (blank). Preferably, it is reduced by 0% or more.

Further, when the optical thin film of the present invention is used for the outermost layer (outermost surface) of the antireflection article of the present invention and a material is selected, another function is exhibited. For example, the use of an optical thin film made of silicon oxide can reduce the contact angle to water to 5 ° or less (expresses hydrophilicity), and has an antifogging function in addition to a low reflection property. In addition, when an optical thin film made of titanium oxide (particularly, titanium oxide containing an anatase crystal phase and / or a rutile crystal phase) is used, a self-cleaning action by photocatalytic activity and hydrophilicity are exhibited.

Further, the optical thin film made of silicon oxide is provided on the outermost layer (outermost surface) of the antireflection article of the present invention, and a titanium oxide layer (particularly containing an anatase crystal phase and a Z or rutile crystal phase) is provided immediately below the optical thin film. By providing a structure provided with the (titanium oxide layer), an antireflection article having sustained hydrophilicity and having an antifogging function can be obtained.

Next, a method for manufacturing an optical thin film will be described.

In the present invention, the matrix phase is a material constituting the optical thin film, and the matrix phase is a dense body. The optical thin film in the present invention is formed by, for example, a two-step process. That is, in the first stage, a composite film composed of a large number of columnar phases grown one-dimensionally and a matrix phase surrounding the columnar phase is formed. The grown columnar phase is removed by etching Remain only the matrix phase.

As a method of forming a composite film in the first stage, a method of directly forming a composite film composed of a one-dimensionally grown columnar phase and a matrix phase surrounding the columnar phase by a physical film forming method (hereinafter, referred to as a composite film). First, an amorphous precursor film is formed on a substrate, and then a eutectic reaction is caused by a heat treatment, whereby a columnar phase grown one-dimensionally and a matrix phase surrounding the columnar phase are formed. (Hereinafter, also referred to as a second method of forming a composite film).

FIG. 1 is a schematic diagram showing a procedure for forming an optical thin film. In the figure, a to d show the procedure for forming the optical thin film of the present invention using the first method for forming a composite film. a is a state in which a composite film 4 composed of a columnar phase 2 and a matrix phase 3 is formed on a substrate 1 by a physical film forming method (initial), b is a state in which a composite film 4 is similarly formed (middle), and c is “D” indicates a state in which the formation of the composite film 4 is completed, and “d” indicates a state in which the columnar phase 2 that has grown one-dimensionally by selective etching is removed, and the optical thin film 5 is formed.

In addition, e to h show procedures for forming an optical thin film using the second method for forming a composite film. e is a state in which an amorphous precursor film 6 containing a transition metal is formed on the substrate 1, f is a state in which a eutectic structure is formed on the film surface by heat treatment, and g is a eutectic reaction interface due to oxygen diffusion from the surface. A state in which a eutectic structure consisting of a columnar phase (transition metal oxide crystal) 2 and a matrix phase 3 surrounding the columnar phase 2 (transition metal oxide crystal) 2 that has finally moved to the film-substrate interface is formed, forming a composite film 4 And h show the state in which the columnar phase 2 that has grown one-dimensionally by selective etching is removed, and the optical thin film 5 is formed.

Hereinafter, the “first stage” of forming an optical thin film will be described.

First, the case where the “first method for forming a composite film” is used is described below.

In the first method of forming a composite film, examples of the physical film forming method for forming the composite film include a sputtering method, an evaporation method, a CVD method, a laser ablation method, and a molecular beam epitaxy method. Among them, the sputtering method is particularly preferable because a dense film can be easily obtained, a film having high adhesion to a substrate can be obtained, and mass productivity and large-area film forming property are excellent. When a composite film is produced by the first method for forming a composite film, the combination of the columnar phase and the matrix phase materials may be any combination that causes the phase separation between the columnar phase material and the matrix phase material during film formation. . In the present invention, since the columnar phase is used in the pore portion after the etching and the matrix phase surrounding the columnar phase is used as a residual phase, the material of the columnar phase is a metal which easily grows in a columnar shape, and Metals or alloys that readily dissolve in force or the like, have low binding energy to the matrix phase material, and are easily reduced are preferred.

As an example of the material of the columnar phase, practically considering the ease of handling during sputtering, the 3d transition metal (V, Cr, Mn, Ni, Fe, Co, Cu, Zn or the like, an alloy containing a 3d transition metal, an alkaline earth metal (such as Mg), and an alloy containing an alkaline earth metal. In addition, A1, In, Sn, and Pb can also be used.

Examples of the matrix phase used as the residual phase include oxides such as silica, alumina, titania, zirconia, mullite, cordierite, spinel, zeolite, and forsterite, silicon carbide, titanium carbide, and zirconium carbide. , Boride such as boron carbide (B ₄ C), boride such as titanium boride, zirconium boride, boron carbide, nitride such as silicon nitride, titanium nitride, zirconium nitride, magnesium fluoride, aluminum fluoride, etc. One or more selected from fluorides and. In addition, a small amount of dopant may be contained in the material within the range of the allowable refractive index.

In the first method of forming a composite film, the microstructure in which the matrix phase surrounds the one-dimensionally grown columnar phase is controlled by controlling the mixing ratio of the columnar phase and matrix phase materials and the film formation conditions. Is done. For example, when forming a composite film by the sputtering method, the average diameter of the growing columnar phase depends on the volume fraction of the columnar phase and the matrix phase and the film forming conditions (such as Ar gas pressure and substrate temperature during sputtering). Has been confirmed to change.

Since the diameter of the one-dimensional through-pores almost matches the diameter of the columnar phase that grows one-dimensionally, the average diameter of the one-dimensional through-pores of the optical thin film finally obtained after etching is the material of the columnar phase and the matrix phase. Mixing ratio and film forming conditions (Ar Gas pressure, substrate temperature, etc.). For example, whereas for C o-S i 〇 ₂ system, if no substrate heating, the particle diameter of 2 P a of A r gas C o in the film formed under pressure is 8 nm, 8 It has been confirmed that when the film is formed under the Ar gas pressure of Pa, the particle size of Co becomes about 40 nm.

An example of manufacturing an anti-reflection article using a sputtering method as a first method of forming a composite film will be described below.

According to the present invention, a plurality of one-dimensionally grown columnar phases and a matrix layer surrounding the columnar phases are formed by sputtering a target made of a material forming a columnar phase and a material forming a matrix phase. After forming a composite film composed of a matrix phase on a substrate, the columnar phase is removed, and a large number of one-dimensionally penetrated walls surrounded by the matrix phase extending from one surface to the other surface of the film are formed. A method of manufacturing an antireflection article for forming an optical thin film having pores, wherein the refractive index of the optical thin film is smaller than the refractive index of the substrate and the refractive index of a material constituting the optical thin film is 1 And a method for producing an antireflection article characterized by having a refractive index between:

Examples of the target include: 1) a target obtained by mixing a powder of a material forming a columnar phase and a powder of a material forming a matrix phase, and 2) a target formed of a material forming a columnar phase. A composite target in which a number of small pieces of a few mm in size, consisting of a material that forms a matrix phase, are arranged on a composite target.3) A columnar phase is formed on a target that is made of a material that forms a matrix phase. And a composite target in which a number of small pieces each having a size of several millimeters made of a material are arranged.

In the present invention, as targets, Rukoto using material T i 0 _2, S i 〇 _2, Z R_〇 _2, S i ₃ N ₄ or M g F ₂ a is evening one target to form a matrix phase It is preferable to use a target in which the material forming the columnar phase is Co.

The ratio (d / r) of the average pore diameter (r) of the aforementioned pores to the average thickness (d) of the wall is 0. In order to obtain an optical thin film having a thickness of about 0.3, a getter composed of a material forming a columnar phase and a material forming a matrix phase is obtained on the target surface of the material forming the columnar phase. The ratio of the area to the total area on the evening-get surface is 0. It is preferable to use a target that is 55 to 0.75. If the area of the material forming the columnar phase on the target surface is v _p and the area of the material forming the matrix phase on the target surface is v _m , the ratio is v _p / (v _p + v _m ) It is represented by If the ratio is less than 0.55, it is difficult to obtain a one-dimensional columnar structure, and if it exceeds 0.75, the strength of the obtained film decreases. The target can be obtained, for example, by 1) mixing and molding both powders so that the ratio of the powder of the material forming the columnar phase is 0.55 to 0.75 in volume ratio to the whole, or 2) columnar Obtained by arranging a small piece of a material forming a matrix phase on a target made of a material forming a phase so that v _p / (v _p + v _m ) is 0.55 to 0.75 .

In the deposition of C o-T i 〇 ₂ composite film, v in the case _{where _{_{p Z (v p + v m}}} ) was used evening one target of 0.8, for mechanical strength of the resulting film is low, etching In some cases, the film shrinks and breaks during subsequent drying, and haze is liable to occur due to peeling of the film. Further, when a target having a v _p Z (V _p + v _m ) of 0.5 was used, Co (colored portion) sometimes remained in the film even after etching. Next, the case where the “second method for forming a composite film” is used will be described below.

In the second method of forming a composite film, a method of forming an amorphous precursor film includes physical film formation such as a sputtering method, a vapor deposition method, a CVD method, a laser ablation method, and a molecular beam epitaxy method. Sol-gel method, spray pyrolysis method, solution method such as coating method, and plating method. Among them, the sputtering method is particularly preferable because it is easy to obtain a dense film and a film having high adhesion to a substrate is obtained, and is excellent in mass productivity and large-area film forming property.

When the amorphous precursor film is formed by the sputtering method, for example, an evening get made of a material forming a columnar phase and a material forming a matrix phase is used. The target is obtained, for example, by mixing powder of a material forming a columnar phase and powder of a material forming a matrix phase. More specifically, the target material for forming a columnar phase consists F e ₃ 〇 _4, also wood charge to form a matrix phase, T I_〇 _2, S I_〇 _2, Z R_〇 _2, S i Target Tsu bets consisting ₃ N ₄ or M g F ₂ and the like.

F e - when forming a S i one O amorphous precursor film, and F e ₃ 0 ₄ powder A mixture of S i 0 ₂ powder evening can be used as Ge' bets.

In the second method for forming a composite film, the combination of elements contained in the amorphous precursor film formed first includes a transition metal element, other metal elements, and oxygen. An example of the transition metal element may be any material that separates from the other metal elements contained in the film into a separate compound phase after heat treatment.From the viewpoint of ease of handling during heat treatment, 3 d Transition metal elements (V, Cr, Mn, NiFe, Co, Cu, Zn, etc.), alloys containing 3d transition metal elements, and rare earth elements (Ce, Nd, Sm, At least one selected from the group consisting of Er) is used as the metal element other than the transition metal element as long as it does not react with the transition metal element during the subsequent heat treatment. Metal elements other than the transition metal element become a matrix phase surrounding the columnar phase (transition metal compound needle-like crystals) during heat treatment, and become a component constituting a film having one-dimensional through-pores after etching. To be elected. Examples of the metal element other than the transition metal element include S i, A 1, Mg, Z r, Sn, and In.

When the amorphous precursor film is formed by sputtering, the diameter of the columnar phase that grows one-dimensionally by the heat treatment performed later changes depending on the Ar gas pressure during the sputtering. For example, in the case of a Fe—Si—〇 system film, when a film formed at an Ar gas pressure of 2 Pa is heat-treated at 600 ° C., a film having a diameter of about 4 nm (Fe ₂ 〇 ₃₎ deposited but, 8 when deposited by a r gas pressure P a, Matthew Bok is precipitated when performing the same process to a diameter of about 2 0 nm. Since the diameter of the one-dimensional through-pores almost matches the diameter of the columnar phase that grows one-dimensionally, the average diameter of the one-dimensional through-pores in the optical thin film finally obtained after etching is determined by the deposition conditions (sputtering conditions). (Ar gas pressure at that time).

In the second method for forming a composite film, a transition metal element and other metal elements and an amorphous precursor film containing oxygen are heat-treated to separate and deposit the transition metal oxide and other metal oxides. Cause a eutectic decomposition reaction. It is important that the two-phase precipitation from the amorphous phase occurs simultaneously and from the film surface. The treatment conditions for heating may be any conditions under which a eutectic decomposition reaction occurs. Ie The temperature may be a temperature at which a eutectic decomposition reaction occurs and a temperature at which the reaction proceeds at a sufficient rate. Specifically, a temperature of about 400 to 65 ° C. is preferable. In order to cause the eutectic decomposition reaction, it is necessary to change the valence of the transition metal. There are two methods for treating the amorphous precursor film in an oxidizing atmosphere and a method in a reducing atmosphere. In the case of an eutectic reaction of an oxide, a uniform eutectic structure may not be formed when treated in a reducing atmosphere. In this case, a uniform eutectic structure can be formed by heat treatment in an oxidizing atmosphere.

In the second method for forming a composite film, when an Fe—Si—O-based amorphous film is formed on a substrate, from the viewpoint of obtaining a one-dimensionally grown iron oxide crystal, a material that forms a columnar phase is used. F e ₃ 0 consists _{of four} (Magunetai g), and materials that form the matrix phase it is preferred that the film with sputtering evening method using a target consisting of S i 0 ₂ (silica).

Hereinafter, the “second stage” of optical thin film formation will be described.

In the second step, only the one-dimensionally extended columnar phase is selectively etched and removed from the composite film formed in the first step using an acid or an alkali. Examples of the acid used in the etching treatment include sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, and acetic acid. For example, the metal to remove the metal C o · S i 〇 ₂ composite film or al metal C o obtained by the first method of forming a composite membrane 0. Lmo 1 Bruno simply by treatment for several minutes with an aqueous nitric acid solution of L Only Co can be completely removed.

In the case of the Fe—Si—O composite film formed by the second method of forming a composite film, the one-dimensionally expanded hematite is soluble in aqueous hydrochloric acid, whereas i 0 ₂ is because it is insoluble in the solution, it can be selectively etched by immersing the film in aqueous hydrochloric acid of about 6 mo 1 ZL.

The substrate on which the optical thin film of the present invention is formed is not particularly limited.

1) When the first method for forming a composite film is used, a substrate or film of glass, ceramics (including sapphire (alumina single crystal), etc.), metal, plastics, etc. can be used.

2) When the second method of forming a composite film is used, glass, ceramics (including sapphire (alumina single crystal), etc.), refractory metals (eg, Fe, Ni, Cr, V Substrates or films such as stainless steel and oxidation-resistant alloys such as Hastelloy) can be used.

The substrate is preferably a transparent substrate (for example, a glass substrate, a single crystal substrate, or a film substrate), and particularly preferably a glass substrate, since the effects of the present invention are particularly remarkably exhibited. The substrate preferably has a refractive index of 1.5 to 1.7. The anti-reflective article of the present invention includes a front glass of a display (such as a CRT panel), a window glass for an automobile (such as a windshield of a vehicle), a window glass for a building, a glass for a mechanical device (a glass for a door of a commercial refrigerator, and the like), Suitable for mirrors and optical lenses. The optical thin film of the present invention has a relatively large porosity because continuous pores extend from the film surface to the inside of the film. Since the pores are sufficiently small compared to the wavelength of light, they do not scatter light, and optically have a refractive index between that of the dense body and that of air (refractive index: 1.00). It becomes a film.

Furthermore, since the optical thin film is surrounded by a continuous matrix phase around the one-dimensional through-pores, the film strength is higher in principle than a conventional porous inorganic film with the same material and porosity. Good adhesion to the substrate. The membrane strength is high because the conventional porous inorganic membrane is formed by loosely binding ceramic particles by sintering, etc., whereas the membrane of the present invention has a completely continuous matrix surrounding the one-dimensional through-pores. This is due to being an integrally molded product.

Regarding the adhesion to the substrate, a film having particularly high adhesion can be obtained by forming the first-stage composite film (including the amorphous precursor film by the second forming method) by a sputtering method or the like. In addition, if the porosity of a conventional porous inorganic film is increased to lower the refractive index, the strength of the film itself and the strength of adhesion between the film and the substrate are reduced, resulting in contradictory problems in characteristics. In many cases, the optical thin film of the present invention has both a low refractive index, a high film strength, and high adhesion to a substrate, and has both a low refractive index and high durability. .

Example

(Example 1)

Using the first method of forming a composite membrane, to form a thin film having a thickness of 1. 2 mm silica glass (quartz) Metal C o and T i 0 ₂ of the two-phase on the base plate. For a spa evening Used a composite target spaced T I_〇 ₂ crystals 5mm square on a metal C o target having a diameter of about 1 5 cm (Ruchi Le type). The ratio of the metal Co target to the total area of the target surface was set at 710.

The vacuum chamber was introduced a A r gas After evacuated to 5 XI 0- ⁴ P a, was generated Burazu Ma by the high-frequency input of the flow rate adjusting 600W as the gas pressure inside the vacuum chamber is 2 P a . The film formation rate was about 0.25 nmZsec, and the substrate was heated to about 200 ° C during film formation. Thus the C o _T i 0 ₂ composite film having a thickness of 1 2 O nm was formed was observed by TEM (transmission electron microscope), C o crystal particles having an average particle diameter of about 8 nm is grown in a columnar Amorphous Ti 0 ₂ was precipitated at the grain boundaries.

A second step, was the C O_T I_〇 ₂ soaked to C o particles 5 minutes composite film nitrate aqueous solution of 0. lmo 1 L produced by the above-described method dissolve and remove almost eluted is C o grains child A clear film remained. The average pore size was about 8 nm. C a o-T i 0 ₂ film after removal of the columnar layer of C o from the composite film was observed with S EM (scanning electron microscope), places the mounting particulate material having a diameter of about several tens of nm No remarkable contrast was seen except that it was worn, and the film was uniform. In the photograph from the cross-sectional direction of the film, a film having a vertical structure remained on the substrate in close contact with the substrate without any gap.

The porosity of the optical thin film formed as described above was estimated from the isothermal adsorption / desorption characteristics of N ₂ gas to be about 73%. The measurement was performed as follows. An optical thin film (thickness lm) was prepared on both sides of a quartz glass substrate with a thickness of 0.1 mm. A sample was prepared and an automatic specific surface area measuring device ("Au tosorb-1" manufactured by Quanta Chrome) was used. The isothermal adsorption and desorption characteristics of nitrogen gas at the temperature of liquid nitrogen were measured by using, and the porosity was obtained from the pore volume obtained from the amount of adsorption and the film thickness.

In addition, the optical thin film-formed surface of the silica glass plate on which the above-mentioned optical thin film was formed and the silica glass plate without the film were measured at a reflection angle of 15 ° using a normal reflection spectrum measuring instrument. When measuring the reflection spectrum, the glass surface opposite to the film-forming surface was roughened using sandpaper, and further painted with black paint. Then, only the reflection on the film surface side (hereinafter referred to as film surface reflection) was measured. The reflectance at the wavelength of 550 nm of the silica glass plate with the optical thin film formed was about 0.28%, which was lower than that of the blank glass (4.2) (93% anti-reflection). There was an emissivity reduction effect). The refractive index estimated from the minimum reflectance around 550 nm was about 1.30, which was significantly smaller than the refractive index (about _2.5 ) of the dense Ti02 film. The refractive index (n _f ) of the optical thin film is estimated as n _f = ( _ns ) ^1/2 X [1 + (R _m ) ^1/2 ] when n _f > ( _ns ) ^1/2 ^1/2 / [1 (R _m ) ^1/2 ] ^1/2 , and if n _f ≤ (n _s ) ^1/2 , n _f = (n _s ) ^1/2 x [1— (R _m ^{^{) 1/2] / 2 / [1}} + (R m) 1/2] 1/2 of formula (n _s is the substrate index of refraction of, R _m was carried out by the minimum reflectance in the vicinity of 5 50 nm).

Table 1 shows the refractive index of the substrate, the refractive index of the matrix phase, the refractive index of the optical thin film, the ratio (dZr) between the average pore diameter (r) and the average thickness (d) of the wall, the porosity (%), The reflection reduction effect (%) when measured at a reflection angle of 15 ° is shown. The same applies to the following examples. However, in Examples 9, 10, 12, and 13, the antireflection performance was evaluated differently.

The durability of the above optical thin film (T i 0 ₂ film having one-dimensional through-pores of the film thickness 1 20 nm), were examined by Taber abrasion resistance test, 1 00 rotates change in transmittance, etc. also are I couldn't see it. The Taber abrasion resistance test was conducted using a commercially available CS10 Taber-type abrasion wheel and abrasive paper of the same quality as AA180 abrasive paper specified in JISR 6252. This was done by abrasion of the film at 100 rpm at 100 rpm. The same applies to the Taber abrasion resistance test in the following examples.

(Example 2)

A Co—Si ₂ composite film was formed on a 1.2 mm thick soda lime glass substrate as follows. In sputtering evening, the S I_〇 ₂ glass chips 0. 5 mm square on the metal C o evening one target with a diameter of about 1 5 cm, C o and S I_〇 ₂ 7 glass the area ratio of 0:30 to Composite targets were used. The other sputtering conditions were the same as in Example 1, and the film was formed. The internal structure of the Co—Si ₂ composite film thus formed is very similar to the structure of the film obtained in Example 1. The amorphous Si ₂ matrix phase surrounds the columnar phase of the Co crystal grains. In this case, the average crystal grain size of the Co crystals was about 1 O nm.

When a sample with a thickness of about 120 nm formed by the above method was etched with an aqueous nitric acid solution in the same manner as in Example 1, the C 0 columnar phase was almost eluted, and the SiO ₂ matrix phase at the grain boundaries remained. . The average pore size was about 10 nm. The minimum reflectance in the visible light range is 0.07%, and it can be used as an anti-reflection film. When the durability of this optical thin film was examined by the same Taber abrasion resistance test as in Example 1, no change was observed in the transmittance and the like after the test.

Next, a drop of pure water having a diameter of about 1 mm was dropped on the surface of the obtained film, and the contact angle was measured to be about 5 °. Also, the S I_〇 ₂ film-coated glass substrate obtained after cooling to about 5 and held 1 hour put in refrigerator, was sprayed with exhalation removed, the portion of the film to no haze On the other hand, small water droplets adhered to the glass surface without the film, and became cloudy and became opaque.

(Example 3)

5mm thick sapphire (alumina single crystal) substrate, in the same manner as in Example 1, was T I_〇 ₂ film having one-dimensional through pores about 1 20 nm formed. The minimum reflectance in the visible light range was 0.01%, and extremely excellent antireflection performance was obtained.

The durability of this optical thin film was examined by a Taber abrasion resistance test similar to that in Example 1, and no change was found in the transmittance or the like after the test.

(Example 4)

The thickness of 1. a polyethylene film sheet of 8 mm, in the same manner as in Example 3, was S 1_Rei ₂ film having one-dimensional through pores about 1 2 O nm formed. The minimum reflectance in the visible light range was 0.07%, and extremely excellent antireflection performance was obtained.

(Example 5)

The thickness 1. 2 mm Seo one da-lime glass substrate, as follows, to form a C o-Z R_〇 ₂ composite film. In sputtering evening, the 21 "0 ₂ chips 0.511 111 corners on the metal C o ter rodents bets with a diameter of about 1 5 cm, C o and Z r 0 6 ₂ area ratio 0: to be the 40 The other target conditions were as follows: A film was formed under almost the same conditions as in Example 1. Thus C o-Z r 〇 ₂ composite film inside the structure formed by the very similar to the structure of the film obtained in Example 1, C o amorphous around the columnar phase crystal grains Z r Although the 0 ₂ matrix phase was surrounded, the average particle size of the Co crystal was about 7 nm in this case.

Was the above method thickness of about 1 2 0 nm formed in the sample was acid-treated in the same manner as in Example 1, C 0 columnar phase substantially eluted Z R_〇 ₂ matrix phase of the grain boundaries remained. The average pore size was about 7 nm. When the durability of this optical thin film was examined by the same Taber abrasion resistance test as in Example 1, no change in transmittance or the like was observed after the test.

(Example 6)

A Co—Si ₃ N ₄ composite film was formed on a 1.2 mm thick soda lime glass substrate as follows. At the time of spattering, a 0.5 mm square Si ₃ N ₄ chip is placed on a metal Co with a diameter of about 15 cm and a 60:40 area ratio of Co and Si ₃ N _4. Was used. Film formation was performed under almost the same conditions as in Example 1 except for the sputtering conditions.

The internal structure of the Co—Si ₃ N ₄ composite film formed in this manner is very similar to the structure of the film obtained in Example 1, in which the amorphous phase around the columnar phase of the Co crystal grains is formed. The Si ₃ N ₄ matrix phase is surrounding, but in this case, the average particle size of the Co crystal was about 6 nm.

The sample having a thickness of about 120 nm formed by the above method was immersed in an aqueous nitric acid solution to dissolve and remove Co particles. As in Example 1, the Co columnar phase was almost eluted, and the Si ₃ N ₄ matrix phase at the grain boundaries remained. The average pore size was about 6 nm. When the durability of this optical thin film was examined by the same Taber abrasion resistance test as in Example 1, no change was observed in the transmittance and the like after the test.

(Example 7)

The thickness of 1. 2 mm soda-lime glass substrate, as follows, to form a C o-M g F ₂ composite film. In the case of a spatter, a metal 15 cm in diameter C 0-a 1 cm square M g F ₂ ceramic chip is placed on the get, and the area ratio of C o to M g F ₂ becomes 70: 30. and adjusting the amount of M g F ₂ ceramic chip so. The film formation was performed under almost the same conditions as in Example 1 except for the sputtering conditions. Thus C o _Mg F ₂ composite film inside the structure formed by the closely resembles the structure of the film obtained in Example 1, C o Mg F ₂ matrix of amorphous around the columnar phase crystal grain The phase is surrounding, but in this case the average size of the C0 crystals was about 12 nm.

The sample having a thickness of about 120 nm formed by the above method was immersed in a 0.1 mo 1 ZL aqueous solution of nitric acid for 5 minutes to dissolve and remove the Co particles. As in Example 1, the Co columnar phase was almost eluted, and the MgF ₂ matrix phase at the grain boundaries remained. The average pore size was about 12 nm. When the durability of this optical thin film was examined by the same Taber abrasion resistance test as in Example 1, no change in transmittance or the like was observed after the test.

(Example 8)

On a heat-resistant glass (Corning # 75059) having a thickness of 1.0 mm, an amorphous precursor film composed of three components of Fe—Si was formed by a sputtering method. Sputtering the evening is, F e ₃ 〇 ₄ powder and 5 i 〇 ₂ powder a mixture sintered in a proportion of 70% and 3 0% in the volume proportion _{_{(i.e., v p / (v p +}} v m ) = 7/10) was used as the target. The vacuum chamber by introducing argon gas vinegar After evacuated to ^{5 X 1 0 _ 4 P a} , and adjusting the flow rate of A r gas so that the gas pressure inside the vacuum chamber is ² P a, 4. 4W cm 2 The high frequency was input to generate plasma. The deposition rate at this time was about 0.2 nm / sec.

When the cross-sectional structure of the formed amorphous precursor film was observed by SEM, an amorphous film having a thickness of about 120 nm was formed on the glass substrate. No defects such as cracks and pores were found in the amorphous film, and a very dense film was formed. Subsequently, this amorphous film was heated in air at 600 for 2 hours. The film after the heat treatment was observed by TEM, one-dimensionally elongated needle of the Ma evening wells (F e ₂ 0 ₃₎ crystal and silica surrounding around its (S i 〇 ₂₎ eutectic structure Had formed. The hematite crystal extended perpendicularly to the film surface from the film surface to the interface with the substrate, and its diameter was about 4 nm.

Finally, the film heat-treated by the above method was immersed together with the substrate in an aqueous solution of about 6 mol 1 ZL of hydrochloric acid at room temperature for 48 hours to remove only hematite. T As a result of EM observation, through pores having a diameter of 4 nm, which was almost the same as that of hematite before the acid treatment, were present in the remaining SiO ₂ film. When the durability of this optical thin film was examined by the same Taber abrasion resistance test as in Example 1, no change in transmittance or the like was observed after the test.

(Example 9)

The thickness 1. 2 mm soda-lime glass substrate, from the substrate side as follows, S N_〇 ₂ / S I_〇 ₂ (dense) ZS i 0 ₂ (film having one-dimensional through-pores), the A three-layer multilayer film was formed. In other words, after evacuating the vacuum chamber to 5 XI 0 _ ⁴ Pa, oxygen gas was introduced at a flow rate adjusted to 0.4 Pa and introduced into a Sn target with a diameter of about 15 cm. by introducing a DC sputtering evening power, to form the S N_〇 ₂ film of 1 4 nm. Next, the substrate was moved onto a silicon target having a diameter of about 15 cm, and a DC sputtering power of 330 W on which a positive potential pulse of 40 kHz was superimposed was applied to the silicon target. 11111 5 1 0 ₂ was formed (dense) film. Thereafter, a SiO ₂ film having one-dimensional through-pores was formed to a thickness of 123 nm according to Example 2.

In addition, the glass surface opposite to the film-forming surface is made to be a non-smooth surface using sandpaper, and after applying black paint, the reflection spectrum of the film-forming surface (hereinafter referred to as the film-forming surface reflection spectrum) is obtained. It was measured. The wavelength region where the reflectance is 1% or less is 390 to 720 nm, and the optical multilayer film has an extremely wide antireflection wavelength region.

(Example 10)

On a soda-lime glass substrate having a thickness of 1.2 mm, a two-layer multilayer film of Sη 0 ₂ / Ύ i 0 ₂ (a film having one-dimensional through-holes) was formed from the substrate side as follows. That is, the vacuum tank 5 X 1 0- ⁴ P a to be introduced with a flow rate adjusted such that the oxygen gas to 0. 4 P a after venting, S n target Bok 3 3 0 a diameter of about 1 5 cm by introducing a DC sputtering power of W, to form the S N_〇 ₂ film 7. 5 nm. Next, as in Example 1, a Ti 一₂ film having one-dimensional through-pores was formed to a thickness of 109 nm.

When the reflection spectrum of the film formation surface was measured, the wavelength region where the reflectance was 1% or less was measured. The wavelength range was 410 to 700 nm, and the optical multilayer film had an extremely wide antireflection wavelength range.

(Example 11)

Except for changing the film thickness to 140 nm in the same manner as in Example 1 by forming a C oT i 0 ₂ double Gomaku was etched. The average pore size of the obtained membrane was about 8 nm.

The resulting T I_〇 ₂ film-coated glass substrate was placed in an electric furnace, the result was heated for 2 hours at 6 00 ° C in air, the film thickness is reduced by about 1 5% (i.e. a thickness of about 1 20 nm An X-ray diffractometer revealed that it contained two types of crystals, anatase and rutile. The refractive index was 1.3, and the minimum reflectance of the film surface was 0.28%.

The T I_〇 ₂ film-coated glass substrate of the film surface after heating by applying a Orein acid was about 85 ° was measured contact angle of water. Then the T I_〇 the film ₂ film-coated glass board, was irradiated 3 50 nm of light (ultraviolet) at an intensity of 4MWZcm ² with black line bets, 1 contact angle of water after 240 hours 5 °, the oleic acid was decomposed and the hydrophilicity was restored.

(Example 1 2)

Seo one da-lime glass substrate, thereby forming a T I_〇 ₂ film containing Anata zero film thickness 1 2 0 nm as a crystal phase by the sol-gel method. Next, an SiO ₂ film was formed in the same manner as in Example 2 except that the film thickness was changed to 100 nm. Incidentally, a mask was applied to the peripheral portion of the substrate, and neither the Ti ₂ film nor the Si 0 ₂ film was formed.

When the reflection spectrum of the film formation surface was measured, the wavelength region where the reflectance was 1% or less was 410 to 700 nm, and the optical multilayer film having an extremely wide antireflection wavelength region was obtained.

A drop of pure water having a diameter of about 1 mm was dropped on the surface of the obtained film, and the contact angle was measured to be about 5 °. The obtained S I_〇 ₂ film-coated glass substrate was kept for 1 hour in the refrigerator 5 t: After cooling to a degree, No fogging does not occur in some parts of Toko filtration, film blowing breath removed On the other hand, small water droplets adhered to the glass surface without the film, and became cloudy and opaque. Further, the obtained glass substrate with a film was left in a room for 3 months, and the contact angle of water was examined again. As a result, the contact angle was about 20 °, and the hydrophilicity was reduced. The membrane of the film-coated glass substrate with a hydrophilic drops was irradiated 3 5 0 nm of light (ultraviolet) at an intensity of 4 mWZ cm ² by using a black line bets, 1 2 0 hour contact angle of water after the It was found that the temperature dropped to 7 ° and the hydrophilicity was restored.

(Example 13)

A Si ₂ film (a film with one-dimensional through-pores) was formed on a 2 mm-thick soda lime glass substrate for automobile windshield as follows. That is, the vacuum chamber was introduced to the flow rate adjusted to the A r gas 1 P a after evacuated to 5 X 1 0- ⁴ P a, the C o-S i 〇 ₂ target length 2. 5 m by introducing a sputtering evening power of 40 kW, to form a C o-S i 〇 ₂ film having a thickness of 1 34. 5 nm. When the obtained film was immersed in an aqueous 0.1 ml 1 ZL nitric acid solution for 5 minutes to dissolve and remove the Co particles, the Co particles were almost eluted, and a transparent SiO ₂ film remained.

Thus the S i 0 ₂ film-coated glass substrate obtained, a film-free glass substrate of the same shape (2mm thick), S i 〇 ₂ film through the intermediate film (polyvinyl butyral) is formed The laminated glass for automobile front was manufactured by bonding so that the uncoated surface was in contact with the interlayer film.

The S I_〇 ₂ film free surface of automobile front Laminated glass obtained by the rough surface in Sandopura strike, further the black paint was applied to measure the film surface reflection of S I_〇 ₂ film forming surface. When the light of wavelength 550 nm is incident on the glass surface at an angle of 60 °, the reflectance is about 8.2%, which is compared to the value without the film (about 15%). Thus, there was an effect of reducing the reflectance by 45%.

(Example 14)

In order to evaluate the adhesiveness of the film to the substrate, a peeling test was performed using cellophane adhesive tape using the samples of Examples 1 to 13 according to the cross-cut tape method (JISK5400). Was. As a result, no peeling that would cause a practical problem was observed in any of the samples.

(Comparative Example 1)

On a silica glass substrate with a thickness of 1.2 mm, use titanium dioxide in a propanol solvent. Sopurobokishido was applied a solution dissolved at a concentration of 0. 5 mo 1 ZL, and heated to about 45 0 ° C, to form a porous T I_〇 ₂ film having a thickness of 1 20 nm. When the durability was examined by the same Taber abrasion resistance test as in Example 1, at 100 revolutions, the film was partially peeled, and the transparency was impaired.

(Comparative Example 2)

An amorphous precursor film composed of three components of Fe-Si10 was formed on a heat-resistant glass (Corning # 7059) substrate having a thickness of 1 · Omm by a sputtering method. Sputtering the evening is used was sintered at a ratio of F e O 70% powder and S i 0 ₂ powder in the volume proportion and 3 0% to evening one Getting Bok. The vacuum chamber by introducing argon gas after evacuated at 5 X 1 0- ⁴ P a or to adjust the flow rate of the A r gas so that the gas pressure inside the vacuum chamber is 2 P a, 4. 4WZ cm Plasma was generated by inputting a high frequency of ² . At this time, the film formation rate was about 0.2 nmZ sec.

When the cross-sectional structure of the formed amorphous precursor film was observed by SEM, an amorphous film having a thickness of about 120 nm was formed on the glass substrate. No defects such as cracks and pores were found in the amorphous film, and a very dense film was formed. Subsequently, this amorphous film was subjected to a heat treatment in air at 600 for 2 hours. When the film after heat treatment was observed by TEM, hematite (F e ₂ 0 ₃₎ having a diameter of several nanometers to granular crystals silica force (S I_〇 ₂₎ tissue dispersed in a matrix is obtained, primary The original eutectic structure was not obtained.

table 1

Industrial applicability

The optical thin film of the present invention has a large number of one-dimensionally penetrated pores surrounded by a continuous wall from one surface to the other surface of the film, has a low refractive index, and has a film strength. And high adhesion to the substrate.

ADVANTAGE OF THE INVENTION According to this invention, the optical thin film of various compositions applicable to many types of base | substrates and the base | substrate with this optical thin film can be provided.

In addition, the diameter of the pores contained in the optical thin film of the present invention is approximately 1 to 500 nm, and there are no huge pores of about several tens / m. Therefore, fine particles such as various types of dust of tobacco floating in the air do not enter and can be removed by simple washing.

Claims

The scope of the claims

1. —The matrix is continuous from one surface to the other surface of the film by removing the columnar phase from a composite film consisting of a large number of dimensionally grown columnar phases and a matrix layer surrounding them. An antireflection article having, on a substrate, an optical thin film formed with a number of pores penetrating in one dimension surrounded by walls made of a phase, wherein the refractive index of the optical thin film is higher than the refractive index of the substrate. An antireflection article characterized by being small and having a refractive index between the refractive index of the matrix phase and 1.

2. The anti-reflective article according to claim 1, wherein the optical thin film is made of silicon oxide or titanium oxide.

3. The antireflection article according to claim 1, wherein the optical thin film is made of titanium oxide containing an anatase crystal phase and / or a rutile crystal phase.

4. The anti-reflection method according to claim 1, wherein the optical thin film made of silicon oxide is provided on an outermost layer, and a titanium oxide layer containing an anatase crystal phase and a Z or rutile crystal phase is provided immediately below the optical thin film. Goods.

5. The antireflection article according to claim 1, wherein the thickness of the optical thin film is 60 to 200 nm.

6. The antireflection article according to claim 1, wherein a ratio (dZr) of an average pore diameter (r) of the pores to an average thickness (d) of the wall is 0.1 to 0.3.

7. A target composed of a material forming a columnar phase and a material forming a matrix phase is sputtered, and a composite film composed of a large number of one-dimensionally grown columnar phases and a matrix phase surrounding the columnar phase is formed. After being formed on the film, the columnar phase is removed to form an optical thin film having a large number of one-dimensionally penetrated pores surrounded by walls composed of the matrix phase continuous from one surface to the other surface of the film. A method for producing an antireflection article, wherein the refractive index of the optical thin film is smaller than the refractive index of the substrate, and the refractive index is between 1 and the refractive index of the material constituting the optical thin film. A method for producing an antireflection article, comprising:

8. The target whose ratio of the area of the material forming the columnar phase on the target surface to the total area on the target surface is 0.55 to 0.75. 8. The method for producing an antireflection article according to claim 7, wherein a get is used.

9. The as targets, according to claim 7 in which the material used T I_〇 _2, S I_〇 _2, Z R_〇 _2, S i ₃ N ₄ or Mg F ₂ a is evening one target to form a matrix phase A method for producing an antireflection article.

As 1 0. the target, method of manufacturing the antireflective article of claim 7, the material forming the columnar phase used target is a C o or F e ₃ 0 _4.