JP2012073542A - Antireflection film and manufacturing method thereof, and optical member and plastic lens having the antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film which improves water vapor barrier properties and suppresses the occurrence of cracks.SOLUTION: An antireflection film has, on its substrate, low refractive index layers including layers at least containing SiOand high refractive index layers. At least one layer of the layers containing SiOis formed through vapor deposition by an ion-assist method.

Description

  The present invention relates to an antireflection film, a manufacturing method thereof, an optical member, and a plastic lens. In particular, the present invention relates to an antireflection film capable of suppressing the occurrence of cracks under high temperature and high humidity, a method for producing the same, an optical member having the antireflection film, and a plastic lens.

2. Description of the Related Art Conventionally, optical members such as lenses, prisms, filters, and the like in which an antireflection layer is provided on a substrate are known. The antireflection layer generally has a structure in which a plurality of inorganic or organic layers having different refractive indexes are laminated. For example, Patent Document 1 describes an antireflection film comprising a total of five layers, in which a high refractive index layer made of Ta ₂ O ₅ and a low refractive index layer made of SiO ₂ are alternately laminated on a substrate. Yes.
In such an antireflection film, a plastic material is often used as a base material because of its light weight and ease of processing. However, in this case, there is a problem that peeling or cracking of the antireflection layer occurs due to a difference in expansion / contraction ratio between the plastic and the antireflection layer due to temperature and humidity changes.
For this problem, for example, in Patent Document 2, the surface of a base material made of a polymer resin is irradiated with an ion beam to modify the surface of the base material, and further, while continuing the ion beam irradiation, By forming a surface coating layer by laminating a low refractive index layer deposited with silicon dioxide, magnesium fluoride, etc. and a high refractive index layer deposited with titanium oxide, zirconium oxide, etc., the surface coating layer and the substrate It is described that the adhesion of the film can be improved and film peeling and cracking can be prevented.

A method of irradiating plasma such as an ion beam when forming a layer by vapor deposition as described in Patent Document 2 is known as a so-called ion assist method.
For example, in Patent Document 3, when SiO ₂ is deposited as a low refractive index layer material, ion assist is performed using Ar as an ionization gas in order to remove stress in the low refractive index layer and improve wear resistance. The method of vapor deposition is described. In addition, it is also described that vapor deposition is performed by an ion assist method using O ₂ and Ar as an ionization gas in order to improve the refractive index and wear resistance during vapor deposition, which is a high refractive index layer material.
In Patent Document 4, Ta ₂ O ₅ is deposited by an oxygen ion assist method in an antireflection film in which a low refractive index layer made of SiO ₂ and a high refractive index layer made of Ta ₂ O ₅ are laminated. Are listed.

Japanese Patent No. 3517264 JP-A-5-45503 JP 2002-71903 A JP 2009-294661 A

  One cause of the occurrence of cracks is elongation due to moisture absorption of the plastic substrate in a high humidity environment. In order to prevent moisture absorption, it is conceivable that the antireflection layer has water vapor barrier performance. However, in order to obtain sufficient water vapor barrier performance, it is necessary to select a vapor deposition material and film formation conditions. In Patent Document 2, modification of the substrate surface by the ion assist method is used to suppress the occurrence of cracks, but the adhesion is improved by the surface modification to suppress the occurrence of cracks. As a result of their studies, it was found that the vapor deposition material and the film forming conditions are insufficient to obtain an antireflection layer having sufficient water vapor barrier performance. Further, in Patent Documents 3 and 4 and the like, an antireflection layer is formed by an ion assist method, but knowledge about improving the water vapor barrier performance of the antireflection layer is not shown.

  In view of the situation as described above, an object of the present invention is to provide a method for producing an antireflection film that has excellent water vapor barrier performance and suppresses the generation of cracks. Another object of the present invention is to provide an antireflection film having excellent water vapor barrier performance and suppressing generation of cracks, and an optical member and a plastic lens having the antireflection film.

As a result of studies by the present inventors, high water vapor barrier performance can be obtained by using SiO _x (x is an oxidation degree and a number of less than 2) having a lower oxidation degree than SiO ₂ normally used for the low refractive index layer. It has been found that an antireflection film having cracks and generation of cracks can be obtained. The SiO _x film is brown due to light absorption and is not suitable for optical materials because of its low transparency. However, the present inventors have further studied, and as a result, the SiO _x film is formed by vapor deposition by ion-assisted deposition. And found that it can be made transparent.

That is, the said subject can be solved by the following means.
[1]
A method for producing an antireflection film having a low refractive index layer including a layer containing at least SiO _x (x represents an oxidation degree and a number less than 2) and a high refractive index layer on a substrate. ,
A method for producing an antireflection film, comprising a step of depositing at least one of the layers containing SiO _x by vapor deposition while irradiating plasma on the substrate.
[2]
The method for producing an antireflection film according to [1], wherein the vapor deposition material of the layer containing SiO _{x formed} by the vapor deposition method is SiO.
[3]
The method for producing an antireflection film according to [1] or [2], wherein an oxidation degree x of SiO _x in at least one of the layers containing SiO _x is 1.0 or more and 1.8 or less.
[4]
The method for producing an antireflection film according to [3], wherein an oxidation degree x of SiO _x in a layer closest to the substrate among the layers containing SiO _x is 1.0 or more and 1.8 or less.
[5]
Any one of [1] to [4], wherein an ultimate pressure at the time of vapor deposition is 1 × 10 ⁻³ Pa or less, an acceleration voltage of plasma ions is greater than 200 V, and an ion current is 300 mA or more. Manufacturing method of antireflection film.
[6]
The method for producing an antireflection film according to any one of [1] to [5], wherein the plasma irradiation is irradiation of argon and oxygen ions.
[7]
The method for producing an antireflection film according to any one of [1] to [6], wherein the high refractive index layer includes a layer containing tantalum oxide or titanium oxide.
[8]
An antireflection film obtained by the production method according to any one of [1] to [7].
[9]
The antireflection film according to [8], wherein the base material is plastic.
[10]
The antireflection film according to [8] or [9], wherein the moisture permeability of at least one of the layers containing SiO _x is 0.1 g / (m ² · day) or less.
[11]
The antireflection film according to any one of [8] to [10], wherein a plurality of the low refractive index layer and the high refractive index layer are laminated.
[12]
An optical member having the antireflection film according to any one of [8] to [11].
[13]
A plastic lens having the antireflection film according to any one of [8] to [11].

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in water vapor | steam barrier performance, the antireflection film in which the crack generation was suppressed, the optical member and plastic lens which have this antireflection film can be obtained.

It is a figure which shows typically the antireflection film produced in the Example. It is a figure which shows the reflective characteristic of the anti-reflective film produced in Example 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto.

The method for producing an antireflection film of the present invention comprises a low refractive index layer including a layer containing at least SiO _x (x is an oxidation degree and a number less than 2) on a substrate, and a high refractive index layer. A method for producing an antireflection film, comprising the step of depositing at least one layer containing SiO _x by vapor deposition on a substrate while irradiating with plasma.

[Antireflection film]
The antireflection film according to the present invention has a low refractive index layer including a layer containing at least SiO _x (x represents an oxidation degree and a number less than 2) on the substrate, and a high refractive index layer. At least one of the layers containing SiO _x is a layer formed by vapor deposition while irradiating plasma on the substrate.
Each of the low refractive index layer and the high refractive index layer may be a single layer or a plurality of layers. The order of stacking the low refractive index layer and the high refractive index layer is not particularly limited, but the layer farthest from the base material (air side layer) is preferably a low refractive index layer.
From the viewpoint of improving the antireflection performance, it is preferable that a plurality of low refractive index layers and high refractive index layers are laminated, and a plurality of low refractive index layers and high refractive index layers are alternately laminated. Is more preferable.

(Base material)
In the antireflection film according to the present invention, the type of the base material is not particularly limited, and may be any of a glass material and a plastic material, but is preferably a plastic material from the viewpoint of light weight and ease of processing.
The plastic material is not particularly limited. For example, cycloolefin copolymer, methyl methacrylate homopolymer, copolymer of methyl methacrylate and one or more other monomers, diethylene glycol bisallyl carbonate homopolymer, diethylene glycol bis Examples include copolymers of allyl carbonate and one or more other monomers, sulfur-containing copolymers, halogen-containing copolymers, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, and polyurethane.
As the base material, commercially available materials can be used. For example, ZEONEX 330R, ZEONEX E48R, ZEONEX F52R (manufactured by Nippon Zeon Co., Ltd.), OKP4-HT (Osaka Gas Chemical Co., Ltd.), EP5000 ( Mitsubishi Gas Resin Co., Ltd.), AD-5503 (Teijin Chemicals Co., Ltd.), and the like.
The refractive index of the substrate is preferably from 1.5 to 1.8, and more preferably from 1.50 to 1.64.

(Low refractive index layer)
In the antireflection film according to the present invention, the low refractive index layer includes at least a layer containing SiO _x (x represents an oxidation degree and a number of less than 2). By including the layer containing SiO _x , the water vapor barrier performance is improved, and the generation of cracks in the antireflection film can be suppressed.
_X of SiO _x represents a number of less than 2 in terms of oxidation degree. When x is less than 2, the water vapor barrier performance is improved, and the generation of cracks in the antireflection film can be suppressed. Preferably it is 1.8 or less, More preferably, it is 1.5 or less.
In addition, when using SiO as a vapor deposition material, the lower limit of x of SiO _x is theoretically 1.0, and is usually about 1.1.
In the antireflection film according to the present invention, it is preferable that oxidation degree x of SiO _x in at least one of the layers containing SiO _x is 1.0 to 1.8, of the layer containing SiO _x It is more preferable that the oxidation degree x of SiO _x in the layer closest to the substrate is 1.0 or more and 1.8 or less. When the layer containing SiO _x have multiple layers may be oxide of the SiO _x is different for each layer.

The water vapor barrier performance of the layer containing SiO _x is preferably low, and the moisture permeability of the layer is preferably 0.1 g / (m ² · day) or less, and 0.01 g / (m ² · day). The following is more preferable. The moisture permeability is preferably as low as possible, but the lower limit is about 0.001 g / (m ² · day). The moisture permeability can be measured based on the MOCON method (JIS K7129B method (infrared sensor method)).

The layer containing SiO _x can contain materials other than SiO _x . Further, as a low refractive index layer, in addition to the layer containing SiO _x, there may be a layer containing a material other than SiO _x. Examples of materials that can be used for the low refractive index layer other than SiO _x include magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), aluminum fluoride (AlF ₃ ), and mixtures thereof. it can.

  The refractive index of the low refractive index layer is preferably 1.35 or more and 1.5 or less, and more preferably 1.38 or more and 1.47 or less. The optical film thickness of the low refractive index layer is preferably 0.14λ0 or more and 0.44λ0 or less from the viewpoint of moisture permeability when the design wavelength λ0 is 500 nm, and is 0.23λ0 or more and 0.35λ0. The following is more preferable. However, it can be 0.14λ0 or less from the viewpoint of optical design or the like, and is not limited to the above range.

(High refractive index layer)
In the antireflection film according to the present invention, examples of the material for the high refractive index layer include lanthanum titanate (LaTiO ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), and tantalum oxide (Ta ₂ O ₅ ). Niobium oxide (Nb ₂ O ₅ ), hafnium oxide (HfO ₂ ), cerium oxide (CeO ₂ ), and mixtures thereof can be used.
In order to suppress cracks and film peeling, it is preferable to give an appropriate compressive stress, and it is also preferable to have film durability. From these viewpoints, the material of the photorefractive index layer is preferably lanthanum titanate (LaTiO ₃ ), titanium oxide (TiO ₂ ), or tantalum oxide (Ta ₂ O ₅ ), and titanium oxide (TiO ₂ ) or tantalum oxide. (Ta ₂ O ₅ ) is preferred.

  The refractive index of the high refractive index layer is preferably 1.7 or more and 2.5 or less, and more preferably 1.8 or more and 2.2 or less. The optical film thickness of the high refractive index layer is preferably 0.036λ0 or more and 0.54λ0 or less, more preferably 0.072λ0 or more and 0.43λ0 or less when the design wavelength λ0 is 500 nm. .

(Other layers)
In the antireflection film according to the present invention, an underlayer may be provided between the base material and the antireflection film. Examples of the material for the underlayer include SiO ₂ . The thickness of the underlayer is preferably 20 nm or more and 100 nm or less.
Moreover, you may have a cured film between a base material and an antireflection film or a base layer. As the cured film, generally a cured film obtained by curing a coating composition comprising metal oxide colloidal particles and an organosilicon compound is generally used. Examples of the metal oxide colloidal particles include tungsten oxide (WO ₃ ), zinc oxide (ZnO), silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and zirconium oxide (ZrO). ₂ ), tin oxide (SnO ₂ ), beryllium oxide (BeO), or antimony oxide (Sb ₂ O ₅ ), and the like can be used alone or in combination of two or more.

Furthermore, a primer layer may be formed in order to improve the adhesion between the cured film and the substrate. When the primer layer is formed, the effect of improving the impact resistance of the antireflection film is imparted. Examples of the constituent material of the primer layer include urethane materials.
Furthermore, a water repellent layer may be provided on the outermost layer of the antireflection film, if necessary.

[Method of manufacturing antireflection film]
Below, the manufacturing method of the anti-reflective film of this invention is demonstrated.
The antireflection film of the present invention is formed by laminating a low refractive index layer and a high refractive index layer on a substrate. Among them, at least one of the low refractive index layers containing SiO _x (hereinafter also referred to as “SiO _x film”) is formed by vapor deposition while irradiating the substrate with plasma. By vapor-depositing while irradiating with plasma, it is possible to obtain a SiO _x film suitable for a transparent optical member having high water vapor barrier performance and suppressing generation of cracks and having no light absorption.
The degree of oxidation of the SiO _x film can be controlled by adjusting the amount of oxygen vacancies in the film by forming a film while irradiating the substrate with plasma. In particular, the amount of oxygen vacancies in the layer can be easily adjusted by adjusting the amount of oxygen gas ions.

Deposition while plasma irradiation can be performed by a method known as an ion assist method.
A gas that is a source of plasma irradiated onto the substrate is not particularly limited, and oxygen gas (O ₂ ), carbon dioxide gas (CO ₂ ), water vapor (H ₂ O), carbon tetrafluoride gas (CF ₄ ). Etc. can be used alone or in combination. From the viewpoint of easy adjustment of the degree of oxidation of a film obtained by vapor deposition, such as a SiO _x film, oxygen gas (O ₂ ) is preferable. Further, argon gas (Ar), nitrogen gas (N ₂₎ may be mixed with an inert gas such as.
In particular, in adjusting the degree of oxidation of the deposited film, a mixture of argon gas and oxygen gas is preferable. In this case, argon and oxygen ions are irradiated to the substrate for plasma irradiation.
The mixing ratio of oxygen gas and argon gas is preferably 4: 1 to 9: 1 and more preferably 5: 1 to 7: 1 in volume ratio.
The inflow of oxygen gas is preferably 30 sccm or more and 70 sccm or less, and more preferably 40 sccm or more and 60 sccm or less.

A voltage is applied to the above gas for acceleration, plasma ionization is performed, and the substrate is irradiated. The acceleration voltage of plasma ions is preferably greater than 200V, more preferably 300V or more, and even more preferably 500V or more. When the acceleration voltage is in the above range, the film density of the SiO _x film is increased, and the water vapor barrier performance can be further improved. The upper limit of the acceleration voltage is not particularly limited, but is preferably 1200 V or less, more preferably 1000 V or less, from the viewpoint of preventing film breakage due to an increase in substrate temperature.
The ion current of plasma ions is preferably 300 mA or more, more preferably 500 mA or more on the substrate. When the ion current is in the above range, the film density of the SiO _x film is increased, and the water vapor barrier performance can be further improved. The upper limit of the ionic current is not particularly limited, but is preferably 1000 mA or less and more preferably 900 mA or less from the viewpoint of preventing film breakage due to an increase in substrate temperature and film peeling due to an increase in film stress.

The ultimate pressure during vapor deposition is preferably 2 × 10 ⁻³ Pa or less, and more preferably 1 × 10 ⁻³ Pa or less. Plasma irradiation and vapor deposition are usually performed in a vacuum apparatus equipped with vapor deposition equipment. In such a case, the ultimate pressure means the degree of vacuum in the vacuum apparatus. The atmosphere pressure at the time of plasma irradiation is preferably 2 × 10 ⁻² or more and 1 × 10 ⁻² or less. To the above pressure range is preferably reduced by degassing, it is particularly preferable to reduce the H _{2 O.} By reducing H ₂ O, the hydroxyl (—OH) component in the SiO _x film is reduced, and the water vapor barrier performance can be improved. This hydroxyl group-containing state can be observed by the FT-IR method.

The deposition of the SiO _x film can be performed by a known method. As the vapor deposition material, SiO, SiO ₂ and a mixture thereof can be used. From the viewpoint of adjusting the degree of oxidation of the vapor deposition film, it is preferable to use SiO. Moreover, in order to avoid the splash at the time of electron beam irradiation, it is preferable to use SiO formed into a pellet or a large granular material of about 10 mm or less.
The substrate temperature during vapor deposition is preferably 85 ° C. or higher and 110 ° C. or lower, and more preferably 90 ° C. or higher and 100 ° C. or lower. The deposition rate is preferably 5 Å / sec or more and 15 Å / sec or less, and more preferably 9 Å / sec or more and 12 Å / sec or less.

The film formation of the low refractive index layer and the high refractive index layer other than the SiO _x film is not particularly limited, but is preferably formed by vapor deposition in the same manner as the SiO _x film from the viewpoint of consistency and simplification of the film forming process. .
Plasma irradiation at the time of vapor deposition may or may not be performed, but it is preferable to perform plasma irradiation at the time of vapor deposition from the viewpoint of suppressing the coloring of the vapor deposition film and increasing the transparency.

For example, when the high refractive index layer is a layer containing titanium oxide (TiO ₂ ) or tantalum oxide (Ta ₂ O ₅ ), TiO ₂ or Ta ₂ O ₅ is used as a deposition material, and TiO ₂ or Ta is used by a known deposition method. A vapor deposited film of ₂ O ₅ can be formed. Plasma may be irradiated onto the substrate during vapor deposition, and the gas serving as the plasma source in this case is preferably a mixture of argon gas and oxygen gas, and the mixing ratio of oxygen gas and argon gas is a volume ratio. The ratio is preferably 4: 1 to 9: 1, more preferably 5: 1 to 7: 1. The inflow of oxygen gas is preferably 30 sccm or more and 70 sccm or less, and more preferably 40 sccm or more and 60 sccm or less. The acceleration voltage of plasma ions is preferably 200 V or more and 1200 V or less, and more preferably 300 V or more and 1000 V or less. The ion current of plasma ions is preferably 300 mA or more and 1000 mA or less, and more preferably 500 mA or more and 900 mA or less on the substrate. The ultimate pressure of vacuum at the time of vapor deposition is preferably 2 × 10 ⁻³ Pa or less, and more preferably 1 × 10 ⁻³ Pa or less. The atmosphere pressure at the time of plasma irradiation is preferably 2 × 10 ⁻² or more and 1 × 10 ⁻² or less.

[Optical members, plastic lenses]
The antireflection film according to the present invention can be suitably used for various optical members such as lenses, prisms, and filters because cracks do not occur even in a high temperature and high humidity environment.
For example, when a plastic having a lens function is used as the base material of the antireflection film, it can be used as a plastic lens with an antireflection film. In this case, it is possible to obtain a transparent plastic lens that has an excellent antireflection effect and does not generate cracks even in a high temperature and high humidity environment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Examples 1 to 3, Comparative Example 1]
An antireflection film having a layer structure shown in FIG. 1 was produced. That is, on the base material 100, the Ta ₂ O ₅ film 1 (high refractive index layer) as the first layer as the high refractive index layer, the SiO _x film 2 (low refractive index layer) as the second layer, and the Ta layer as the third layer. _An antireflection film 10 in which a ₂ O ₅ film 3 (high refractive index layer) and a SiO _x film 4 (low refractive index layer) were stacked as a fourth layer was produced.
ZEONEX 330R (Nippon Zeon Co., Ltd.) was used as the substrate 100, and a Ta ₂ O ₅ film and a SiO _x film were formed thereon. Here, about Examples 1-3, it formed into a film by the ion assist method. The deposition material for _{the Ta} 2 _{O 5} film uses _Ta 2 _{O 5,} the SiO _x film was used SiO. Other film forming conditions are shown in Table 1 below.
The moisture permeability of the SiO _x films 2 and 4 was measured on the basis of the MOCON method by independently forming films on the resin film under the same film forming conditions. The measurement results are shown in Table 1 below.
The optical film thickness of each layer is λ0 = 500 nm, the Ta ₂ O ₅ film 1 is 0.12λ0, the SiO _x film 2 is 0.08λ0, the Ta ₂ O ₅ film 3 is 0.19λ0, and the SiO _x film 4 is It was set to 0.28λ0.
FIG. 2 shows the reflection characteristics of the antireflection film produced in Example 1.

The obtained antireflection film was allowed to stand in an environment of 85 ° C. and 95% RH for 1000 hours, and then the antireflection film was observed with an optical microscope for the presence or absence of cracks, and evaluated according to the following criteria. The evaluation results are shown in Table 2 below.
○: No cracks are observed in the antireflection film.
Δ: One or two cracks are observed in the antireflection film.
X: Three or more cracks are seen in the antireflection film.

From the results shown in Table 1, it can be seen that the antireflection film of the present invention, in which a layer containing SiO _x is formed by vapor deposition by an ion assist method, suppresses the generation of cracks even in a high temperature and high humidity environment.

[Reference example]
On the base material ZEONEX330R (Nippon ZEON Co., Ltd.), the SiO ₂ film and the SiO _x film were individually formed under the conditions shown in Table 2 below. Each film thickness is 100 nm. When the vapor deposition method was an ion assist method, oxygen gas and argon gas were introduced at inflow amounts of 50 sccm and 8 sccm, respectively, and the substrate was irradiated with plasma.
After film formation, moisture permeability was measured based on the MOCON method. The measurement results are shown in Table 2 below.
The normal deposition of the SiO ₂ film and the SiO _x film was performed by EB irradiation without inflow of oxygen gas and Ar gas.

From the results in Table 2, it can be seen that the SiO _x film is superior in water vapor barrier performance compared to the SiO ₂ film, and further, when formed by the ion assist method, the water vapor barrier performance is further improved.
The SiO _x film formed by normal vapor deposition was brown, but the SiO _x film formed by the ion assist method was transparent.

1 Ta ₂ O ₅ film (high refractive index layer)
2 SiO _x film (low refractive index layer)
3 Ta ₂ O ₅ film (high refractive index layer)
4 SiO _x film (low refractive index layer)
10 Antireflection film 100 Base material

Claims (13)

A method for producing an antireflection film having a low refractive index layer including a layer containing at least SiO _x (x represents an oxidation degree and a number less than 2) and a high refractive index layer on a substrate. ,
A method for producing an antireflection film, comprising a step of depositing at least one of the layers containing SiO _x by vapor deposition while irradiating plasma on the substrate. The method for producing an antireflection film according to claim 1, wherein a vapor deposition material of a layer containing SiO _{x formed} by the vapor deposition method is SiO. The method for producing an antireflection film according to claim 1 or 2, wherein an oxidation degree x of SiO _x in at least one of the layers containing SiO _x is 1.0 or more and 1.8 or less. The method for producing an antireflection film according to claim 3, wherein an oxidation degree x of SiO _x in a layer closest to the substrate among the layers containing SiO _x is 1.0 or more and 1.8 or less. The ultimate pressure of the atmosphere at the time of the vapor deposition film formation is 1 × 10 ⁻³ Pa or less, the acceleration voltage of plasma ions is greater than 200 V, and the ion current is 300 mA or more. Manufacturing method of antireflection film.   The method for producing an antireflection film according to claim 1, wherein the plasma irradiation is irradiation of argon and oxygen ions.   The method for producing an antireflection film according to claim 1, wherein the high refractive index layer includes a layer containing tantalum oxide or titanium oxide.   An antireflection film obtained by the production method according to claim 1.   The antireflection film according to claim 8, wherein the base material is plastic. The antireflection film according to claim 8 or 9, wherein moisture permeability of at least one of the layers containing SiO _x is 0.1 g / (m ² · day) or less.   The antireflection film according to claim 8, wherein a plurality of the low refractive index layer and the high refractive index layer are laminated.   An optical member having the antireflection film according to any one of claims 8 to 11.   The plastic lens which has an antireflection film in any one of Claims 8-11.

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