JP7304129B2 - Antireflection film, manufacturing method thereof, and polarizing plate with antireflection layer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antireflection film having an antireflection layer composed of a plurality of thin films on a transparent film, and a method for producing the same.

BACKGROUND ART An antireflection film is used on the viewer side surface of an image display device such as a liquid crystal display or an organic EL display for the purpose of preventing deterioration of image quality due to reflection of external light or reflection of an image and improving contrast. An antireflection film has an antireflection layer formed of a laminate of a plurality of thin films having different refractive indices on a transparent film.

One form of the antireflection film is a polarizing plate with an antireflection layer. A polarizing plate with an antireflection layer can be obtained by laminating an antireflection film on the surface of a polarizing plate or by laminating an antireflection film as a protective film on the surface of a polarizer. An antireflection layer may be formed on the surface of the polarizing plate.

Some attempts to impart water vapor barrier properties to antireflection layers are known. For example, in Japanese Unexamined Patent Application Publication No. 2002-100000, the vapor barrier property is improved by forming alternately laminated films of ITO and SiO ₂ by sputtering, and forming a silicon oxide film thereon by plasma CVD. In Patent Document 2, the low moisture permeability of the antireflection film is attempted by providing a silicon nitride film with a high refractive index. Patent Document 3 describes that there is a high correlation between the density of the outermost layer (the layer farthest from the film substrate) of the antireflection layer and the moisture permeability.

JP-A-2000-338305 JP-A-2003-139907 JP 2009-109850 A

By providing an antireflection layer having water vapor barrier properties on the surface of the polarizing plate, deterioration of the polarizer in a high-humidity environment is suppressed and durability is improved. In recent years, displays have come to be required to have further high humidity durability, and antireflection films with higher water vapor barrier properties (lower moisture permeability) than conventional ones are required. In view of the above, an object of the present invention is to provide an antireflection film having excellent water vapor barrier properties.

The antireflection film of the present invention has an antireflection layer composed of a plurality of thin films having different refractive indices on one main surface of a transparent film substrate. The antireflection layer includes a primer layer in contact with the transparent film substrate. It is preferable that high refractive index layers and low refractive index layers are alternately laminated on the primer layer. The moisture permeability of the antireflection film is preferably 1 g/m ² ·24 h or less.

The argon content of the primer layer is preferably 0.01 to 0.5 atomic percent . The primer layer is preferably a silicon oxide layer. The primer layer is preferably formed by sputtering. It is preferable that the thin film on the primer layer constituting the antireflection layer is also formed by a sputtering method.

Furthermore, the present invention relates to a polarizing plate with an antireflection layer having the above antireflection film on one surface of a polarizer.

The antireflection film of the present invention has excellent bus barrier properties, and even when a display having a polarizing plate with an antireflection layer with low moisture permeability on its surface is exposed to a high humidity environment, the amount of moisture entering the polarizer is small. , the deterioration of the polarizer can be suppressed.

1 is a cross-sectional view schematically showing one form of an antireflection film. FIG. 1 is a cross-sectional view schematically showing one embodiment of a polarizing plate with an antireflection layer; FIG.

[Configuration of antireflection film]
FIG. 1 is a cross-sectional view schematically showing the structure of an antireflection film according to one embodiment. The antireflection film 100 has an antireflection layer 5 in contact with the transparent film substrate 1 . The antireflection layer is a laminate of two or more thin films, and the antireflection layer 5 shown in FIG. 53 and low refractive index layers 52 and 54 are alternately laminated.

The moisture permeability of the antireflection layer 5 is preferably 1 g/m ² ·24h or less, more preferably 0.7 g/m ² ·24h or less. 0.5 g/m ² ·24 h or less is more preferable. By reducing the moisture permeability of the antireflection layer, it is possible to prevent moisture from entering and suppress deterioration of the polarizer and the like due to moisture. As will be detailed later, when the amount of argon contained in the primer layer is small, the moisture permeability of the antireflection film tends to be low.

<Transparent film substrate>
A transparent film substrate 1 includes a flexible transparent film 10 . A hard coat layer 11 is preferably provided on the side of the transparent film 10 on which the antireflection layer 5 is formed.

(Transparent film)
The visible light transmittance of the transparent film 10 is preferably 80% or higher, more preferably 90% or higher. Although the thickness of the transparent film 10 is not particularly limited, it is preferably about 5 to 300 μm, more preferably 10 to 250 μm, and even more preferably 20 to 200 μm from the viewpoint of strength, workability such as handleability, and thinness.

Examples of the resin material that constitutes the transparent film 10 include thermoplastic resins that are excellent in transparency, mechanical strength, and thermal stability. Specific examples of such thermoplastic resins include cellulose-based resins such as triacetyl cellulose, polyester-based resins, polyethersulfone-based resins, polysulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, and polyolefin-based resins. , (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.

(Hard coat layer)
By providing the hard coat layer 11 on the surface of the transparent film 10, mechanical properties such as hardness and elastic modulus of the antireflection film can be improved. The hard coat layer 11 preferably has high surface hardness and excellent scratch resistance. The hard coat layer 11 can be formed, for example, by applying a solution containing a curable resin onto the transparent film 10 .

Examples of the curable resin include thermosetting resin, ultraviolet curable resin, electron beam curable resin, and the like. Examples of curable resins include various resins such as polyester, acrylic, urethane, acrylic urethane, amide, silicone, silicate, epoxy, melamine, oxetane, and acrylic urethane. One or more of these curable resins can be appropriately selected and used.

Among these resins, acrylic resins, acrylic urethane resins, and epoxy resins are preferable, and acrylic urethane resins are particularly preferable because they have high hardness, can be cured with ultraviolet rays, and are excellent in productivity. UV-curable resins include UV-curable monomers, oligomers, polymers, and the like. Preferred UV-curable resins include, for example, those having UV-polymerizable functional groups, and those containing acrylic monomers or oligomers having two or more, particularly three to six, functional groups as components.

The hard coat layer 11 may have antiglare properties so that the antireflection film has antiglare properties and antiglare properties. Examples of the antiglare hard coat layer include those in which fine particles are dispersed in the curable resin matrix described above. Fine particles dispersed in the resin matrix include various metal oxide fine particles such as silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide, glass fine particles, polymethyl methacrylate, polystyrene, and polyurethane. , acrylic-styrene copolymers, benzoguanamine, melamine, polycarbonate, and other transparent polymers.

The hard coat layer 11 can be formed, for example, by applying a solution containing a curable resin onto the transparent film 10 . The solution for forming the hard coat layer preferably contains an ultraviolet polymerization initiator. In order to form an antiglare hard coat layer containing fine particles, it is preferable to apply a solution containing the above fine particles in addition to the curable resin onto the transparent film. The solution may contain additives such as leveling agents, thixotropic agents, and antistatic agents.

Although the thickness of the hard coat layer 11 is not particularly limited, it is preferably 0.5 μm or more, more preferably 1 μm or more, in order to achieve high hardness. Considering ease of formation by coating, the thickness of the hard coat layer is preferably 15 μm or less, more preferably 10 μm or less.

The arithmetic mean roughness Ra of the surface of the transparent film substrate 1 on the side where the antireflection layer 5 is formed is preferably 1.0 nm or less. When the hard coat layer 11 is formed on the transparent film 10, the arithmetic mean roughness Ra of the hard coat layer 11 is the arithmetic mean roughness of the surface of the transparent film 10 on which the antireflection layer 5 is formed. The arithmetic mean roughness Ra is obtained from an observation image of 1 μm square using an atomic force microscope (AFM).

By forming the hard coat layer 11 by coating as described above, the arithmetic mean roughness of the surface of the transparent film substrate 1 can be reduced. If the surface of the transparent film substrate 1 is smooth, defects such as pinholes in the antireflection layer 5 can be suppressed, so that an antireflection film with lower moisture permeability can be obtained.

(surface treatment)
The surface of the transparent film substrate 1 is subjected to corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, saponification treatment, and coupling agent for the purpose of improving adhesion with the antireflection layer 5. A surface modification treatment such as treatment may be performed.

<Antireflection layer>
An antireflection film is formed by providing an antireflection layer 5 on a transparent film substrate 1 . The antireflection layer 5 has a primer layer 50 on the surface in contact with the transparent film substrate 1, and has a high refractive index layer and a low refractive index layer thereon. In general, the antireflection layer has an optical thickness (product of refractive index and thickness) of the thin film so that the reversed phases of incident light and reflected light cancel each other out. By making the antireflection layer a multi-layer laminate of a plurality of thin films having different refractive indices, the reflectance can be reduced in a wide wavelength range of visible light.

Materials for the thin film forming the antireflection layer 5 include metal oxides, nitrides, and fluorides. A preferable material for the primer layer 50 is silicon oxide. The primer layer 50 has an argon content of 0.5 atomic % or less. The low refractive index layers 52 and 54 have, for example, a refractive index of 1.6 or less, preferably 1.5 or less. Examples of low refractive index materials include silicon oxide and magnesium fluoride. The high refractive index layers 51 and 53 have, for example, a refractive index of 1.9 or more, preferably 2.0 or more. Examples of high refractive index materials include titanium oxide, niobium oxide, zirconium oxide, indium tin oxide (ITO), and antimony-doped tin oxide (ATO). In addition to the low refractive index layer and the high refractive index layer, as a medium refractive index layer with a refractive index of about 1.6 to 1.9, for example, a thin film made of titanium oxide or a mixture of the above low refractive index material and high refractive index material may be provided.

A method for forming the thin film forming the antireflection layer 5 is not particularly limited, and either a wet coating method or a dry coating method may be used. A dry coating method such as vacuum deposition, CVD, sputtering, or electron beam deposition is preferred because it can form a thin film with a uniform thickness. Among them, the sputtering method is preferable because it is easy to form a dense film with excellent film thickness uniformity and high gas barrier properties. In particular, in order to obtain an antireflection film with low moisture permeability, it is preferable to deposit silicon oxide as the primer layer 50 by a sputtering method.

In the sputtering method, a plurality of thin films can be continuously formed while a long film substrate is transported in one direction (longitudinal direction) by a roll-to-roll method, so productivity of the antireflection film can be improved. In order to improve the productivity of the antireflection film, it is preferable to deposit all the thin films constituting the antireflection layer 5 by sputtering. In the sputtering method, a film is formed while an inert gas such as argon and, if necessary, a reactive gas such as oxygen are introduced into the chamber.

The deposition of the oxide layer by the sputtering method can be carried out by either a method using an oxide target or reactive sputtering using a metal target. RF discharge is required to deposit an insulating oxide such as silicon oxide using an oxide target. Reactive DC sputtering using a metal target is preferable for forming a metal oxide film at a high rate.

(primer layer)
The amount of argon in the primer layer 50 is 0.5 atomic % or less, preferably 0.4 atomic % or less. When the amount of argon in the sputtered film is 0.5 atomic % or less, the moisture permeability tends to be reduced, and the antireflection film tends to improve the water vapor barrier property. It is not clear why the moisture permeability of the antireflection layer is low due to the reduction in the amount of argon in the primer layer. This is thought to be related to the fact that a path of gas such as water vapor is likely to be formed in the thin film.

As described above, in sputtering film formation, argon is used as a process gas, high-energy argon collides with the target to eject the material from the target, and the sputtered particles ejected from the target are deposited on the substrate. Film formation is performed. Inert gases such as argon generally do not participate in film formation, but since ionized argon is highly reactive, part of the argon used as a process gas is inevitably incorporated into the film during sputtering film formation. .

Since argon, which is a rare gas, has a larger atomic diameter than silicon and oxygen, the argon taken into the film inhibits the formation of the Si—O bond network of silicon oxide, forming atomic-level voids. can be. When voids are formed in the primer layer 50 which is deposited first in contact with the film substrate 1 due to the inclusion of argon, high refractive index layers 51 and 53 and low refractive index layers 52 and 54 are formed thereon by sputtering. When the film is formed, the voids tend to grow in a columnar shape in the thickness direction, and it is thought that these become paths for gases such as water vapor, increasing the moisture permeability. On the other hand, it is thought that by reducing the amount of argon taken into the primer layer 50, the formation of voids through which water vapor passes is suppressed, and a low moisture-permeable antireflection layer with excellent water vapor barrier properties is formed. .

Although it is preferable that the amount of argon contained in the primer layer 50 is as small as possible, a film obtained by sputtering film formation using argon as a process gas usually contains 0.01 atomic % or more of argon. The argon content in the primer layer may be 0.05 atomic % or more, or 0.1 atomic % or more. The amount of argon in the film is measured by the Rutherford Backscattering (RBS) method, and the amount of argon in the silicon oxide film is a calculated value with the total content of silicon, oxygen and argon being 100 atomic %.

As a method for suppressing the contamination of argon into the primer layer, it is preferable to decrease the process pressure during film formation to increase the mean free path and promote the scattering of argon. The process pressure for forming the primer layer 50 is preferably about 0.05 to 2 Pa, more preferably about 0.07 to 1 Pa, even more preferably 0.1 to 0.5 Pa, particularly 0.1 to 0.3 Pa. preferable. The amount of oxygen introduced into the film forming chamber when the primer layer 50 is formed is preferably about 0.1 to 10%, more preferably about 0.5 to 5%, and more preferably about 1 to 3% of the amount of argon introduced in volume ratio. A degree is more preferred.

By introducing oxygen in addition to argon during sputtering film formation to promote the formation of a Si—O bond network, there is a tendency to suppress argon from entering the film. On the other hand, in order to improve the adhesion between the film substrate 1 and the antireflection layer 5, the oxygen content of the primer layer 50 is preferably less than the stoichiometric composition. The film thickness of the primer layer 50 may be such that the transparency of the transparent film substrate 1 is not impaired, and is, for example, about 1 to 10 nm.

(thin film on primer layer)
The type of thin film formed on the primer layer 50 is not particularly limited. From the viewpoint of reducing the reflectance over a wide wavelength range, it is preferable to alternately provide the high refractive index layers and the refractive indexes. In order to reduce reflection at the air interface, the thin film 54 provided as the outermost layer (the layer farthest from the film base 1) of the antireflection layer 5 is preferably a low refractive index layer. As the material for the low refractive index layer and the high refractive index layer, oxides are preferable as described above. Among them, it is preferable to alternately stack niobium oxide (Nb ₂ O ₅ ) thin films 51 and 53 as high refractive index layers and silicon oxide (SiO ₂ ) thin films 52 and 54 as low refractive index layers.

In the sputter deposition of the low refractive index layer and the high refractive index layer on the primer layer, it is preferable to control the oxygen introduction amount so that the deposition mode is in the transition region. For example, in the plasma emission monitoring method (PEM method) in which the plasma emission intensity of the discharge is detected to control the amount of gas introduced into the deposition chamber, feedback to the oxygen introduction amount is performed based on the plasma emission intensity. By controlling the amount of oxygen introduced by PEM, the film formation rate can be kept constant when forming a thin film by the roll-to-roll method, so the film thickness of the thin film becomes uniform, and the reflection with excellent anti-reflection properties is achieved. A protective film is obtained. By providing a plurality of plasma emission measurement points in the width direction and independently controlling the amount of oxygen introduced by the PEM, the uniformity of quality in the width direction can also be improved.

<Additional layer on antireflection layer>
The antireflection film may have an additional functional layer on the surface of the antireflection layer 5 . Since the antireflection film is placed on the top surface of the display, it is susceptible to contamination (fingerprints, fingerprints, dust, etc.) from the external environment. In particular, the low refractive index layer 54 such as SiO ₂ provided on the outermost surface of the antireflection layer 5 has good wettability, and contaminants such as fingerprints and fingerprints are likely to adhere thereto. An antifouling layer (not shown) may be provided on the antireflection layer for the purpose of preventing contamination from the external environment and facilitating removal of adhering contaminants.

The antifouling layer preferably has a small refractive index difference with the low refractive index layer 54 on the outermost surface of the antireflection layer 5 . The refractive index of the antifouling layer is preferably 1.6 or less, more preferably 1.55 or less. As the material for the antifouling layer, fluorine group-containing silane compounds, fluorine group-containing organic compounds, and the like are preferable. The antifouling layer can be formed by a wet method such as a reverse coating method, a die coating method, or a gravure coating method, or a dry method such as a CVD method. The thickness of the antifouling layer is usually about 1 to 100 nm, preferably 2 to 50 nm, more preferably 3 to 30 nm.

[Polarizing plate with antireflection layer]
An antireflection film is used, for example, by placing it on the surface of a display. As shown in FIG. 2, a polarizing plate with an antireflection layer in which an antireflection film 100 is laminated with a polarizer 8 may be attached to the surface of the display. In the antireflection layer-attached polarizing plate 101 shown in FIG. 2, one surface of the polarizer 8 is attached to the main surface of the transparent film substrate 1 opposite to the surface on which the antireflection layer 5 is formed. A transparent film 9 is attached to the other surface of the polarizer 8 . In this configuration, the film substrate 1 has both a function as a substrate for forming the antireflection layer 5 and a function as a protective film for the polarizer 8 . In the production of the antireflection film, the polarizer 8 and the film substrate 1 may be bonded together to produce a polarizing plate, and the antireflection layer 5 may be formed on the film substrate 1 of the polarizing plate.

As the polarizer 8, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, an ethylene/vinyl acetate copolymer system partially saponified film, etc. is coated with a dichroic film such as iodine or a dichroic dye. Polyene-based oriented films such as those obtained by adsorbing a substance and uniaxially stretching, dehydrated polyvinyl alcohol, dehydrochlorinated polyvinyl chloride, and the like can be mentioned.

Among them, since it has a high degree of polarization, a polyvinyl alcohol-based film such as polyvinyl alcohol or partially formalized polyvinyl alcohol is oriented in a predetermined direction by adsorbing a dichroic substance such as iodine or a dichroic dye. Alcohol (PVA) based polarizers are preferred. For example, a PVA-based polarizer can be obtained by subjecting a polyvinyl alcohol-based film to iodine dyeing and stretching. A thin polarizer having a thickness of 10 μm or less can also be used as the PVA-based polarizer. Thin polarizers are described in, for example, JP-A-51-069644, JP-A-2000-338329, WO2010/100917, JP 4691205, JP 4751481, etc. A thin polarizing film can be mentioned. Such a thin polarizer can be obtained, for example, by a manufacturing method including a step of stretching a laminate of a PVA-based resin layer and a stretching resin substrate, and a step of dyeing with iodine.

As the transparent film 9, the same materials as those described above as the material of the transparent film 10 are preferably used. The material of the transparent film 9 and the material of the transparent film 10 may be the same or different.

An adhesive is preferably used for bonding the polarizer and the transparent film. Adhesives are based on acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl alcohol, polyvinyl ether, vinyl acetate/vinyl chloride copolymer, modified polyolefin, epoxy polymer, fluorine polymer, rubber polymer, etc. Polymers can be appropriately selected and used. A polyvinyl alcohol-based adhesive is preferably used for bonding the PVA-based polarizer.

The antireflection film and the polarizing plate with an antireflection layer of the present invention are used in displays such as liquid crystal display devices and organic EL display devices. In particular, when it is used as the outermost layer of a display, it contributes to the improvement of the visibility of the display due to antireflection. By providing the low-moisture-permeable antireflection film 100 including the predetermined primer layer 50 on the surface of the polarizer 8 , it is possible to prevent moisture from entering the polarizer 8 from the external environment. Therefore, even when the display is exposed to a high-humidity environment, yellowing and fading due to deterioration of the polarizer are unlikely to occur, and changes in display characteristics can be suppressed.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[Preparation of film with hard coat layer]
UV curable acrylic resin (manufactured by DIC, trade name “GRANDIC PC-1070”, refractive index: 1.52) 100 parts by weight (solid content) and 50 parts by weight of nano silica particles as an inorganic filler are mixed, A composition for forming a hard coat layer was prepared. This composition was applied to one side of a 100 μm-thick cellulose triacetate film (manufactured by Fujifilm, trade name “Fujitac”) so as to give a thickness of 5 μm after drying, and dried at 80° C. for 3 minutes. After that, using a high-pressure mercury lamp, the coating layer was cured by irradiating ultraviolet light with an accumulated light amount of 200 mJ/cm ² to form a hard coat layer.

[Example 1]
The triacetyl cellulose film on which the hard coat layer is formed is introduced into a roll-to-toll type sputtering deposition apparatus, and while the film is running, the surface on which the antiglare hard coat layer is formed is bombarded (plasma treatment with Ar gas). , a 3.5 nm silicon oxide layer was deposited as a primer layer, and thereon a 12 nm Nb ₂ O ₅ layer, a 28 nm SiO ₂ layer, a 100 nm Nb ₂ O ₅ layer and an 85 nm SiO 2 layer. _Two layers were formed in order to prepare an antireflection film.

Bombardment treatment was performed at a pressure of 1.5 Pa. A silicon oxide layer as a primer layer was formed by DC sputtering at a substrate temperature of −8° C., an argon flow rate of 300 sccm, an oxygen flow rate of 4.5 sccm, a pressure of 0.2 Pa, and a power of 0.5 W/cm ² applied to a Si target. did A Si target was used for the deposition of the SiO ₂ layer, and a Nb target was used for the deposition of the Nb ₂ O ₅ layer. In the deposition of the SiO ₂ layer and the Nb ₂ O ₅ layer, the amount of introduced oxygen was adjusted by plasma emission monitoring (PEM) control so that the deposition mode maintained the transition region.

[Example 2 and Comparative Example 1]
The conditions for forming the primer layer by sputtering were changed as shown in Table 1, and in Comparative Example 1, the primer layer was formed without introducing oxygen. In Comparative Example 1, the argon flow rate was changed to 1200 sccm and the pressure to 0.45 Pa. Except for this, an antireflection film was produced in the same manner as in Example 1.

[Evaluation of antireflection film]
(moisture permeability)
According to JIS K7129:2008 Appendix B, the moisture permeability of the antireflection film was measured in an atmosphere of 40° C. and 90% RH. Since the moisture permeability of the film substrate is sufficiently higher than that of the antireflection layer, the moisture permeability of the entire antireflection film was considered to be equal to that of the antireflection layer.

(Film density and composition of thin film)
The film density and composition of the thin film constituting the antireflection layer were measured by the Rutherford Backscattering (RBS) method. In calculating the film density, the film thickness obtained from cross-sectional transmission electron microscope (TEM) observation was used. ), the sum of the contents of oxygen and argon was calculated as 100 atomic %.

[Preparation of polarizing plate with antireflection layer and evaluation of durability]
The antireflection films of Examples and Comparative Examples were laminated to one surface of the polarizer, and a transparent film having a thickness of 30 μm made of a modified acrylic polymer having a lactone ring structure was laminated to the other surface of the polarizer, A polarizing plate with an antireflection layer was produced. As the polarizer, a PVA-based polarizer obtained by stretching a polyvinyl alcohol film having an average degree of polymerization of 2700 and a thickness of 75 μm to 6 times while dyeing with iodine was used. For adhesion between the PVA-based polarizer and the transparent film, a polyvinyl alcohol resin containing an acetoacetyl group (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetoacetylation: 5 mol%) and methylolmelamine are used. Using an adhesive consisting of an aqueous solution contained at a weight ratio of 3:1, they were bonded together by a roll bonding machine, and then dried by heating in an oven.

The obtained polarizing plate with an antireflection layer was placed in a constant temperature and humidity chamber at 60° C. and 90% RH, and taken out after 72 hours. A commercially available polarizing plate was placed on the backlight, and the amount of change Δb ^* in the chromaticity b ^* of the transmitted light before and after the heating and humidification test was determined.

The film properties of each layer of the antireflection layer of Examples and Comparative Examples, the film formation conditions of the primer layer, the moisture permeability of the antireflection film, and the amount of change in transmitted light b ^* before and after the heating and humidification test of the polarizing plate with the antireflection layer were measured. Table 1 shows.

As shown in Table 1, the antireflection films of Examples 1 and 2 have lower moisture permeability than Comparative Example 1, and the polarizing plate with an antireflection layer has a small chromaticity difference before and after the heating and humidification test. showed excellent durability. There was no clear difference in the film density of the outermost SiO ₂ layer (film thickness: 85 nm) between the example and the comparative example.

Since Nb ₂ O ₅ has a higher moisture permeability than SiO ₂ , in the alternate laminate film of SiO ₂ and Nb ₂ O ₅ , the moisture permeation of the SiO ₂ film is rate-limiting, and the moisture permeability is mainly due to the SiO ₂ film. depends on the characteristics of _In Comparative Example 1, the film density of the Nb ₂ O ₅ layer tended to be lower than in Examples 1 and 2 because the film formation pressure of the _{Nb 2 O 5} layer was low. It is considered that the difference in film density of the layers has little effect on the change in moisture permeability.

Examples 1 and 2 and Comparative Examples 1 and 2 differ in film formation conditions for the primer layer. , the amount of argon in the film changed compared to Comparative Examples 1 and 2. From these results, it was found that in Examples, the amount of argon contained in the primer layer was reduced, thereby improving the water vapor barrier property of the antireflection film (lowering the moisture permeability) and improving the durability of the polarizing plate with the antireflection layer. It is thought that

REFERENCE SIGNS LIST 1 transparent film substrate 10 transparent film 11 hard coat layer 5 antireflection layer 50 primer layer 51, 52, 53, 54 thin film 8 polarizer 9 transparent film 100 antireflection film 101 polarizing plate with antireflection layer

Claims (10)

An antireflection film comprising an antireflection layer composed of a plurality of thin films having different refractive indices on one main surface of a transparent film substrate,
The antireflection layer includes a primer layer in contact with the transparent film substrate,
The antireflection film, wherein the primer layer is a silicon oxide layer, and the argon content is 0.01 to 0.5 atomic percent. The antireflection film according to claim 1 , wherein the antireflection layer comprises alternating high refractive index layers and low refractive index layers on the primer layer. The high refractive index layer is a niobium oxide layer, the low refractive index layer is a silicon oxide layer, and the amount of oxygen in the silicon oxide of the primer layer is less than the amount of oxygen in the silicon oxide of the low refractive index layer. The antireflection film according to claim 2 . 4. The antireflection film according to claim 1, which has a moisture permeability of 1 g/m ² ·24 h or less. The antireflection film according to any one of claims 1 to 4 , wherein the transparent film substrate has a hard coat layer on the surface in contact with the primer layer. A polarizing plate with an antireflection layer comprising the antireflection film according to any one of claims 1 to 5 on one side of a polarizer. A method for producing the antireflection film according to any one of claims 1 to 5 ,
A method for producing an antireflection film, wherein the primer layer is formed by a sputtering method. 8. The method for producing an antireflection film according to claim 7 , wherein all thin films constituting said antireflection layer are formed by a sputtering method. 9. The method for producing an antireflection film according to claim 7 , wherein oxygen is introduced in addition to argon and the process pressure is 0.05 to 0.2 Pa when forming the primer layer by sputtering. The production of the antireflection film according to any one of claims 7 to 9 , wherein oxygen is introduced in a volume ratio of 0.1 to 10% relative to argon when forming the primer layer by sputtering. Method.

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