JP2008268328A - Reflection preventing film and polarizing plate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection preventing film which is excellent in mechanical characteristics such as scratch resistance, and also is excellent in durability under high temperature surroundings, and to provide a polarizing plate having the reflection preventing film. <P>SOLUTION: The reflection preventing film is formed by sequentially laminating at least hard coat layers and reflection preventing layers on at least one surface of a transparent base film, wherein arithmetic average roughness Ra of the reflection preventing layer surface on the opposite side of a surface in contact with the hard coat layer is ≥1.5 nm to ≤3.0 nm. Also the reflection preventing layer is constructed by laminating a plurality of optical thin film layers with mutually different refractive indexes, and is formed by using a sputtering method under the pressure atmosphere of ≥0.5 Pa to ≤2.0 Pa. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a highly durable antireflection film having high density and high mechanical strength and less degradation such as hydrolysis of a polarizing plate protective film, and a polarizing plate using the same.

  In an optical display device such as an LCD, CRT, or plasma display panel, an antireflection film that prevents reflection of external light such as sunlight or a fluorescent lamp is often used. Recently, not only indoor use but also outdoor use is increasing due to the spread of mobile devices such as digital cameras, mobile phones, digital video cameras, and car navigation.

  For outdoor use where the reflection of outside light is large, an antireflection film, that is, an AR film, having a reflectance close to zero is required. In general, the AR film uses a dry coating technique capable of forming a thin film having a thickness of several nanometers. Among these, the sputtering method is a thin film with higher visibility than other dry coating methods such as vapor deposition, ion plating, and CVD because it has higher film thickness uniformity and fewer defects such as pinholes. Can be formed. In addition, since a dense film can be formed, it is possible to form a thin film with extremely excellent mechanical properties.

  On the other hand, in an LCD application, an antireflection layer having a structure laminated on a protective film of a polarizing plate is often used. In recent years, a polarizing plate or an antireflection film is required to have higher required durability performance with an increase in use in a vehicle or an outdoor environment. Generally, a triacetyl cellulose (TAC) film is used as a protective film for a polarizing plate because of its high hygroscopicity. However, under severe conditions of high temperature or high temperature and high humidity, the TAC film is hydrolyzed, so that it lacks durability.

Therefore, antireflection layers having various water vapor barrier properties have been developed. According to Japanese Patent Application Laid-Open No. 2004-53797 of Patent Document 1, an antireflection layer having a barrier property that is less than half that of a substrate is formed. is doing. According to JP-A-10-10317 JP-Patent Document 2, a light-transmissive inorganic thin film layer 300~1000g ^/ m 2 ^/ day to one side of a plastic film, on the other side of 0 to 10 g ^/ m 2 / day barrier The thin film layer is formed.

On the other hand, due to an increase in the frequency of use in the current outdoor environment, durability at an extremely high temperature close to 100 ° C. is required particularly for in-vehicle applications. At this time, if the water vapor barrier property is too high, there is almost no ingress of moisture from the outside, but in particular, in a high temperature environment, moisture generated from the polarizing plate and the TAC film itself stagnate in the film, so it is rather durable. I have found the problem of lack of sex. Therefore, development of an antireflection film having a reasonably high permeability to the outside of water vapor generated inside is desired.
JP 2004-53797 A Japanese Patent Laid-Open No. 10-10317

As described above, the sputtering method has the advantages of excellent uniformity in film thickness control and few defects such as pinholes, and thus has high visibility and high yield in the production stage. Furthermore, since a very dense film can be formed, there is a great advantage that an antireflection layer excellent in mechanical properties such as scratch resistance can be formed.
On the other hand, a thin film formed by this sputtering film formation has a feature that the barrier performance of water vapor is higher than other film formation methods because of the high density of the film.

  Accordingly, an object of the present invention is to form an antireflection film having a dense and scratch-resistant mechanical property, a high moisture permeability, and a high humidity and heat durability.

The invention according to claim 1 is an antireflection film formed by sequentially laminating at least a hard coat layer and an antireflection layer on at least one surface of a transparent substrate film,
The antireflection film is characterized in that the arithmetic average roughness Ra of the surface of the antireflection layer opposite to the surface in contact with the hard coat layer is 1.5 nm or more and 3.0 nm or less.

  The invention according to claim 2 is the antireflection film according to claim 1, wherein the antireflection layer is formed by laminating a plurality of optical thin film layers having different refractive indexes.

  A third aspect of the present invention is the antireflection film according to the first or second aspect, wherein the antireflection layer is formed using a sputtering method.

  The invention according to claim 4 is the antireflection film according to claim 3, wherein the pressure at the time of forming the antireflection layer is 0.5 Pa or more and 2.0 Pa or less.

  The invention according to claim 5 is characterized in that an alkali saponification treatment is applied to the transparent substrate film provided with the hard coat layer before the antireflection layer is formed. This is an antireflection film.

  A sixth aspect of the present invention is the antireflection film according to any one of the first to fifth aspects, wherein a surface of the hard coat layer is subjected to a low-temperature plasma surface treatment before the antireflection layer is formed.

  The invention according to claim 7 is made of a metal, an alloy composed of two or more kinds of metals, a metal compound, or a mixture thereof between the hard coat layer and the antireflection layer. The antireflection film according to claim 1, further comprising a primer layer comprising:

The invention according to claim 8 is opposite to the surface in contact with the transparent substrate film after the alkali saponification treatment according to claim 5 or after the low-temperature plasma surface treatment according to claim 6. The arithmetic average roughness Ra of the surface of the hard coat layer on the side, and the arithmetic average roughness Ra of the surface of the primer layer opposite to the surface in contact with the hard coat layer after forming the primer layer according to claim 7 ,
The transparent substrate film before the alkali saponification treatment according to claim 5 and the low-temperature plasma surface treatment according to claim 6 and before forming the primer layer according to claim 7 Rather than the arithmetic average roughness Ra of the surface of the hard coat layer that is opposite to the contact surface and is untreated,
The antireflection film according to claim 5, wherein the antireflection film has a size of 0.2 nm to 4.5 nm.

  The invention according to claim 9 is the antireflection film according to any one of claims 1 to 8, wherein an antifouling layer is provided on the antireflection layer.

  The invention according to claim 10 is the antireflection film according to any one of claims 1 to 9, wherein the transparent substrate film is a triacetyl cellulose film.

The invention according to claim 11 is characterized in that the water vapor permeability at a temperature of 40 ° C. and a relative humidity of 90% RH is 20 g / m ² / day or more, and the antireflection according to any one of claims 1 to 10 It is a film.

  A twelfth aspect of the invention is a polarizing plate having the antireflection film according to any one of the first to eleventh aspects.

  ADVANTAGE OF THE INVENTION According to this invention, the antireflection film excellent in mechanical characteristics, such as abrasion resistance, and excellent in durability in a high temperature environment, and a polarizing plate having the same can be provided.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a cross-sectional view showing an embodiment of the antireflection film of the present invention.
In FIG. 1, an antireflection film 100 of the present invention has a hard coat layer 2, a primer layer 3, and an antireflection layer 4 sequentially laminated on a transparent substrate film 1. Further, an antifouling layer 5 is laminated on the antireflection layer 4.

  As the transparent substrate film 1 in the present invention, a substrate which is a surface protective layer of a polyvinyl alcohol film on which a polarizer is adsorbed is applied. The transparent substrate film 1 is not particularly limited as long as the effects of the present invention are achieved, but cellulose acetate resins such as triacetyl cellulose have particularly high protection performance and are preferably used. Furthermore, when using these, the acetylation degree is not ask | required. What is necessary is just to select the thickness of the transparent base film 1 suitably according to the intended use, and the thing about 25 micrometers or more and 300 micrometers or less is used normally. Moreover, the transparent base film 1 may contain additives such as a plasticizer, an ultraviolet absorber, and a deterioration preventing agent.

  On the transparent substrate film 1, the hard coat layer 2 for sufficiently exhibiting the mechanical strength of the antireflection layer 4 is provided. As the hard coat layer 2 in the present invention, an ionizing ray, an ultraviolet curable resin, or a thermosetting resin is used, and ultraviolet curable acrylic esters, acrylamides, methacrylic esters, methacrylamide, and the like are used. Acrylic resins, organosilicon resins, and polysiloxane resins are most suitable. A polymerization initiator may be added to these materials in order to improve curability. The hard coat layer 2 has a physical thickness of 0.5 μm or more, preferably 3 μm or more and 20 μm or less. The hard coat layer 2 may be subjected to an antiglare treatment by dispersing transparent fine particles having an average particle size of 0.01 μm or more and 3 μm or less.

  After laminating the hard coat layer 2 on the transparent substrate film 1, it is preferable to perform an alkali saponification treatment. In particular, when a triacetyl cellulose film is used as the transparent substrate film 1, the triacetyl cellulose film is preferably subjected to an alkali saponification treatment for imparting a hydroxyl group in order to hydrolyze an ester group. Adhesiveness in bonding with the polyvinyl alcohol layer 10 is remarkably improved (see FIG. 2). Further, since the alkali saponification treatment is a treatment in a liquid, the erosion / penetration is high, and the hard coat layer 2 also has improved adhesion to the layer to be subsequently laminated.

  Further, after the alkali saponification step, surface treatment may be applied to the hard coat layer 2 on the side opposite to the surface in contact with the transparent substrate film 1. At this time, examples of the surface treatment method include corona discharge treatment, electron beam treatment, flame treatment, glow discharge treatment, atmospheric pressure plasma treatment and the like. In the present invention, it is particularly preferable to perform low-temperature plasma surface treatment. . By applying the low temperature plasma surface treatment, the hydrophilicity can be further improved, and the surface of the hard coat layer 2 is appropriately roughened to further improve the adhesion with the thin film laminated on the hard coat layer 2. be able to.

  Thereafter, the primer layer 3 may be provided on the hard coat layer 2. Examples of the material of the primer layer 3 include metals such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium, or alloys composed of two or more of these metals, or These oxides, fluorides, sulfides, nitrides, etc. may be mentioned, which may be a mixture. Further, the primer layer 3 may have two or more layers.

The primer layer 3 is used for improving adhesion. The thickness should just be a grade which does not impair the transparency of the transparent base film 1, Preferably, it is a physical film thickness and is about 1 nm or more and 10 nm or less.
These primer layers are preferably formed by a dry coating method such as a sputtering method, a reactive sputtering method, a vapor deposition method, an ion plating method, or a chemical vapor deposition (CVD) method. A sputtering method is particularly preferred.

  The arithmetic average roughness Ra of the surface of the hard coat layer 2 opposite to the surface in contact with the transparent base film 1 after the alkali saponification treatment or the low temperature plasma surface treatment, and the primer layer 3 The arithmetic average roughness Ra of the surface of the primer layer 3 opposite to the surface in contact with the hard coat layer 2 after being formed is before the alkali saponification treatment and the low temperature plasma surface treatment, and the primer layer 3 It is preferably 0.2 nm or more and 4.5 nm or less larger than the arithmetic average roughness Ra of the surface of the hard coat layer 2 that is opposite to the surface in contact with the transparent base film 1 and is untreated before formation. By forming minute irregularities so that the arithmetic average roughness Ra is 0.2 nm or more and 4.5 nm or less larger than the surface of the untreated hard coat layer 2, adhesion to the antireflection layer 4 to be laminated thereafter is performed. And mechanical strength is improved.

  The antireflection layer 4 includes a single layer of a low refractive index transparent thin film layer having a light refractive index of less than 1.6 at a wavelength of 550 nm and a light extinction coefficient of 0.5 or less at a wavelength of 550 nm, or a wavelength of 550 nm. High refractive index transparent thin film layer having a light refractive index of 1.9 or higher, low refractive index transparent thin film layer having a light refractive index of less than 1.6, medium refractive index of light having a refractive index of about 1.6 to 1.9 Examples thereof include a plurality of layers in which optical thin films having different refractive indexes such as a transparent thin film layer are laminated. An antireflection layer composed of a plurality of layers is preferable because of its extremely low reflectance and high antireflection performance. As the antireflection layer 4 comprising a plurality of layers, a structure in which a high refractive index transparent thin film layer, a low refractive index transparent thin film layer, a high refractive index transparent thin film layer, and a low refractive index transparent thin film layer are laminated in order from the substrate side. Can be mentioned.

  As the material for the high refractive index transparent thin film layer, indium, tin, titanium, silicon, zinc, zirconium, niobium, magnesium, bismuth, cerium, tantalum, aluminum, germanium, potassium, antimony, neodymium, lanthanum, thorium, hafnium, etc. Examples thereof include metals or alloys composed of two or more of these metals, oxides thereof, fluorides, sulfides, and nitrides. Specific examples include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, and cerium oxide, but are not limited thereto. In addition, when a plurality of layers are stacked, it is not always necessary to select the same material, and the material may be appropriately selected according to the purpose.

  Examples of the material for the low refractive index transparent thin film layer include, but are not limited to, materials such as silicon oxide, titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. In addition, when a plurality of layers are stacked, it is not always necessary to select the same material, and it may be appropriately selected according to the purpose.

  Examples of the intermediate refractive index transparent thin film layer include aluminum oxide and cerium fluoride.

  The antireflection layer 4 made of these optical thin film layers can be formed by a dry coating method such as sputtering, reactive sputtering, vapor deposition, ion plating, or chemical vapor deposition (CVD). It is preferable to use a sputtering method that has high film thickness uniformity and few defects such as pinholes, and that is excellent in visibility, dense, and capable of forming a thin film with excellent mechanical properties such as scratch resistance. Among them, the dual magnetron sputtering (DMS) method, in which film formation is performed by applying a voltage in the middle frequency region, is optimal because higher productivity can be obtained by higher film formation speed and higher discharge stability.

  The arithmetic average roughness Ra of the surface of the antireflection layer 4 in the present invention is 1.5 nm or more and 3.0 nm or less. If the value of the arithmetic average roughness Ra is less than 1.5 nm, the film density is high, so that the water vapor transmission rate of the antireflection layer 4 itself becomes too low, and as shown in FIG. When the plate is formed, moisture generated from the polarizing film 10 and the transparent substrate film 1 (TAC film) itself stagnate in the film, so that sufficient performance can be obtained in durability tests such as heat resistance and moisture heat resistance. Can not. Conversely, if the value of the arithmetic average roughness Ra is greater than 3.0 nm, sufficient mechanical properties such as scratch resistance and adhesion cannot be obtained.

  In addition, as a method for setting the arithmetic average roughness Ra of the surface of the antireflection layer 4 to 1.5 nm or more and 3.0 nm or less, a film forming method can be selected. The film forming pressure may be optimized and can be realized easily. An appropriate film forming pressure by the sputtering method is 0.5 Pa or more and 2.0 Pa or less. When the film forming pressure is in a range of 0.5 Pa or more and 2.0 Pa or less, a porous film can be formed while maintaining the mechanical characteristics peculiar to sputtering, and the antireflection layer 4 having high durability can be formed. Can be created.

  An antifouling layer 5 may be provided on the outermost surface layer on the antireflection layer 4 as necessary. The antifouling layer 5 is a layer obtained from a fluorine-containing silicon compound having two or more silicon atoms bonded to a reactive functional group. The reactive functional group in the present invention means a group capable of reacting with and bonding to the uppermost layer of the antireflection layer 4. Moreover, it is a layer formed by making the reactive functional groups of a fluorine-containing silicon compound react. Thereby, it is hard to get dirt on the surface, and even if it gets dirty, the wiping performance can be improved.

  When the antifouling layer 5 is provided on the antireflection layer 4, the arithmetic average roughness Ra of the antifouling layer 5 surface is preferably 1.0 nm or more and 3.5 nm or less. According to this, the antireflection performance and the wiping performance can be further improved by smoothing the surface of the antireflection layer 4.

By the way, the water vapor transmission amount of these antireflection films changes under the influence of the material and thickness of the base material and the functional layer, and further the temperature and humidity. The temperature dependency of moisture permeability is expressed by the Arrhenius equation shown below.
P = P0e-E / RT
P: Moisture permeability (unit thickness, water vapor transmission rate per unit water vapor pressure difference)
P0: Absolute zero degree of moisture permeability E: Moisture permeability activation energy R: Gas constant T: Absolute temperature

In the case of a triacetyl cellulose film that is widely used as a surface protective film for a polarizing plate, the water vapor transmission rate with a thickness of 100 μm is 120 g / m ² / day to 160 g / m ² / day, at a temperature of 25 ° C. and a relative humidity of 90%. It becomes 380 g / m ² / day at 40 ° C. and 90% relative humidity. By laminating various layers on the triacetyl cellulose film, water vapor hardly penetrates the film. In particular, the water vapor transmission rate of the antireflection layer having excellent mechanical properties and a dense film laminated is almost zero, and exhibits excellent water vapor barrier performance.

  In the antireflection layer 4 formed by laminating a plurality of inorganic compounds, if at least one of the layers has excellent water vapor barrier properties, the water vapor barrier performance of the whole antireflection film having the antireflection layer 4 is high. Become. Since the water vapor barrier performance is too high, the moisture inside the anti-reflection film eliminates the escape route to the outside, stays inside the anti-reflection film, and becomes a factor that reduces the durability. It is necessary to improve the performance so as to speed up the process moderately.

  That is, in the present invention, the water vapor permeability of the antireflection layer 4 is adjusted, and it is fine so that the arithmetic average roughness Ra of the untreated hard coat layer 2 surface is 0.2 nm or more and 4.5 nm or less. By forming the irregularities, the low moisture permeability, which is a characteristic of the dense film, is improved, while maintaining the characteristics capable of forming a dense film, which is a great advantage of the sputtering method. It is possible to form the antireflection layer 4 having good durability and high durability.

The antireflective film of the present invention has moderate moisture permeability and good adhesion, so that the water vapor permeability at a temperature of 40 ° C. and a relative humidity of 90% RH is 20 g / m ² / day or more. It is preferably 40 g / m ² / day or more and more preferably 250 g / m ² / day or less.

  Next, with reference to FIG. 2, the polarizing plate 101 having the antireflection film 100 will be described. FIG. 2 is a cross-sectional view showing an embodiment of a polarizing plate 101 having the antireflection film 100 of the present invention. The polarizing plate 101 is prepared by laminating and bonding an antireflection film 100, a polyvinyl alcohol film 10 dyed with iodine, and a transparent base film 1 made of the same material as the transparent base film 1 on the opposite surface in this order. can do. In addition, about layer structures other than the antireflection film 100, not only this but a well-known technique is employable.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not limited to the following Example.

[Example 1]
As shown in FIG. 2, after using a triacetyl cellulose having a thickness of 80 μm on the transparent substrate film 1, applying an ultraviolet curable acrylic resin, drying and ultraviolet curing, and providing a 5 μm hard coat layer 2, The arithmetic average roughness Ra of the surface of the untreated hard coat layer 2 was measured. Thereafter, the film was immersed in a 1.5N NaOH solution at 40 ° C. for 2 minutes, washed with water and dried.

  A glow plasma treatment is performed on the hard coat layer 2 subjected to the saponification treatment, and an SiO layer is formed as a primer layer 3 with an optical film thickness of 6 nm under the conditions of an electric power of 2.0 kW and an argon gas flow rate of 150 sccm. The arithmetic average roughness Ra of the surface of the subsequent hard coat layer 2 was measured.

Thereafter, four layers of TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ were provided as the antireflection layer 4 in the order of film formation. The film formation of TiO ₂ has an electric power of 2.5 kW, an argon gas flow rate of 150 sccm, an oxygen gas flow rate of 30 sccm, and the film formation of SiO ₂ has an electric power of 2.0 kW, an argon gas flow rate of 150 sccm, and an oxygen gas flow rate of 20 sccm. The pressure in the layer was 0.8 Pa.

The optical film thickness of each antireflection layer 4 is monitored by an optical film thickness monitor, and the film formation time is set so that the optical film thickness of the antireflection layer 4 is 60 nm / 44 nm / 105 nm / 145 nm, respectively. Set.
Thereafter, the arithmetic average roughness Ra of the antireflection layer 4 surface was measured.

  Thus, as shown in FIG. 2, the 25-micrometer-thick polyvinyl alcohol film 10 and the 80-micrometer-thick triacetyl cellulose 1 which were dye | stained with iodine are bonded to the back surface of the created antireflection film 100, and an antireflection function is provided. A polarizing plate 101 was prepared.

[Example 2]
A polarizing plate 101 with an antireflection function was formed under the same conditions as in Example 1 except that the deposition pressure of the antireflection layer 4 was 1.2 Pa.

[Comparative Example 1]
A polarizing plate with an antireflection function was formed under the same conditions as in Example 1 except that the deposition pressure of the antireflection layer was 0.2 Pa.

[Comparative Example 2]
A polarizing plate with an antireflection function was formed under the same conditions as in Example 1 except that the deposition pressure of the antireflection layer was 2.5 Pa.

[Comparative Example 3]
After providing the hard coat layer on the triacetyl cellulose film, it was bonded to the polarizing plate without providing the antireflection layer.

[Evaluation]
Samples obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 1.

(1) Steel Wool Abrasion Test Steel wool # 0000 is fixed to an abrasion tester, a load of 500 gf is applied, and a 10-reciprocal abrasion test is performed on the antireflection layer of each sample. ) Was observed visually.

(2) Heat resistance test The polarizing plate created in the examples and comparative examples was attached to glass via an adhesive film, and the temperature and humidity chamber was set under conditions of a dry environment at a temperature of 95 ° C and a relative humidity of 5%. The durability was evaluated. The presence or absence of degradation such as hydrolysis of the cellulose film was judged by visual observation, confirmation of acetic acid odor, and change in absorption spectrum of carbonyl group in infrared spectroscopic measurement.

(3) Moisture and heat resistance test The polarizing plate created in the examples and comparative examples was attached to glass via an adhesive film, and the temperature and humidity chamber was set under conditions of a dry environment at a temperature of 60 ° C and a relative humidity of 95%. The durability was evaluated. The presence or absence of degradation such as hydrolysis of the cellulose film was judged by visual observation, confirmation of acetic acid odor, and change in absorption spectrum of carbonyl group in infrared spectroscopic measurement.

(4) Water vapor transmission rate The water vapor transmission rate in an environment of a temperature of 40 ° C. and a relative humidity of 90% Rh was measured in the antireflection layer before the polarizing film was attached. The water vapor transmission rate was measured using a method according to JIS Z0208.

(5) Arithmetic average roughness measurement The arithmetic average roughness measurement of the antireflection layer was performed using an atomic force microscope (AFM) Nanoscope 3a (Digital Instruments) in accordance with a method according to JIS B 0601. The measurement area was 1 μm × 1 μm.

In the polarizing plate provided with the antireflection film prepared in Examples 1 and 2, since the scratch resistance is good, the adhesiveness is good. Furthermore, in heat resistance and moist heat resistance, the polarizing plate and the polarizing plate are 1000 hours or more. The protective film has excellent durability without deterioration, and the effect of the present invention can be confirmed. On the other hand, in Comparative Example 1, although the scratch resistance was excellent, hydrolysis of the TAC film occurred in 120 hours and 750 hours, respectively, in terms of heat resistance and moist heat resistance. In Comparative Example 2, it can be confirmed that the heat resistance and the moist heat resistance are excellent, but the scratch resistance is poor. Further, in Comparative Example 3, it can be confirmed that although the adhesiveness is excellent, the heat resistance, the moist heat resistance, and the water vapor barrier property are poor.

It is a figure which shows the structure of the anti-reflective film created by this invention. It is a figure which shows the polarizing plate which has the antireflection layer created by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base film 2 Hard-coat layer 3 Primer layer 4 Antireflection layer 5 Antifouling layer 10 Polarizing film (polyvinyl alcohol)
100 Antireflection film 101 made according to the present invention 101 Polarizing plate having an antireflection layer made according to the present invention

Claims (12)

An antireflection film formed by sequentially laminating at least a hard coat layer and an antireflection layer on at least one surface of the transparent substrate film,
An antireflection film, wherein the arithmetic average roughness Ra of the surface of the antireflection layer opposite to the surface in contact with the hard coat layer is 1.5 nm or more and 3.0 nm or less.   The antireflection film according to claim 1, wherein the antireflection layer is formed by laminating a plurality of optical thin film layers having different refractive indexes.   The antireflection film according to claim 1, wherein the antireflection layer is formed using a sputtering method.   The antireflection film according to claim 3, wherein a pressure during film formation of the antireflection layer is 0.5 Pa or more and 2.0 Pa or less.   The antireflection film according to claim 1, wherein an alkali saponification treatment is performed on the transparent substrate film provided with the hard coat layer before forming the antireflection layer.   The antireflection film according to claim 1, wherein the surface of the hard coat layer is subjected to a low-temperature plasma surface treatment before forming the antireflection layer.   Between the hard coat layer and the antireflection layer, a primer layer made of a metal, an alloy made of two or more metals, a metal compound, or a mixture thereof was provided. The antireflection film according to any one of claims 1 to 6. Arithmetic on the surface of the hard coat layer opposite to the surface in contact with the transparent substrate film after the alkali saponification treatment according to claim 5 or the low temperature plasma surface treatment according to claim 6 The average roughness Ra, and the arithmetic average roughness Ra of the surface of the primer layer opposite to the surface in contact with the hard coat layer after forming the primer layer according to claim 7,
The transparent substrate film before the alkali saponification treatment according to claim 5 and the low-temperature plasma surface treatment according to claim 6 and before forming the primer layer according to claim 7 Rather than the arithmetic average roughness Ra of the surface of the hard coat layer that is opposite to the contact surface and is untreated,
The antireflection film according to any one of claims 5 to 7, wherein the antireflection film is 0.2 nm or more and 4.5 nm or less.   The antireflection film according to any one of claims 1 to 8, wherein an antifouling layer is provided on the antireflection layer.   The antireflection film according to claim 1, wherein the transparent substrate film is a triacetyl cellulose film. The water-vapor permeability at a temperature of 40 ° C and a relative humidity of 90% RH is 20 g / m ² / day or more, and the antireflection film according to any one of claims 1 to 10.   A polarizing plate comprising the antireflection film according to claim 1.

Images