JP2003105540A - Silica layer and antireflection film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silica layer having an excellent chemical resistance even when the silica layer is formed by a plasma enhanced CVD process and to provide an antireflection film utilizing this silica layer. SOLUTION: The silica layer which is formed by the plasma enhanced CVD process and of which the refractive index is 1.40 to 1.46 (λ=550 nm) and the IR absorption by C-H stretching vibrations at 2,800 to 3,000 cm<-1> and the IR absorption by Si-CH3 stretching vibrations at 1,200 to 1,400 cm<-1> are respectively <=0.1 cm<-1> is provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silica layer and an antireflection film using the silica layer.

[0002]

2. Description of the Related Art Various displays used for computers such as liquid crystal displays, plasma displays, CRTs, word processors, televisions, display boards, display bodies such as measuring instruments, rearview mirrors, goggles, window glasses, etc. An antireflection film is used to prevent light from being reflected on the surface.

The antireflection film is generally formed by forming a laminate of a combination of thin layers (low refractive index layer, medium refractive index layer, high refractive index layer) having various refractive indexes on a substrate. Thus, the interference of light is used to prevent reflection.

At present, the outermost layer (the surface opposite to the base of the antireflection film) in the antireflection film provided with such a laminate has a small refractive index in order to efficiently prevent the reflection of light. It is known that it is preferable to provide a layer, that is, a so-called low refractive index layer, and a silica layer is preferably used as the layer having a small refractive index.

Conventionally, a vacuum vapor deposition method or a sputtering method has been used as a method for producing an antireflection film having a laminate in which such thin layers are laminated.

However, when the antireflection film is manufactured by the vacuum vapor deposition method, a problem often occurs in the adhesion between the thin layers forming the laminate of the antireflection film. On the other hand, when the antireflection film is produced by the sputtering method, there is a problem that the formation speed of each thin layer is slow.

In order to solve such a problem, a technique for forming a laminate of antireflection films by the plasma CVD method is currently being researched and developed. This is because according to the plasma CVD method, high adhesion between the thin layers can be obtained, and the formation rate of the thin layers is high.

[0008]

However, the laminated body of the antireflection film produced by the plasma CVD method has a new problem that it may be inferior in chemical resistance. For example, during the manufacturing process of the antireflection film, a step of subjecting the laminate to an alkali treatment may be performed, and the thin layer formed by the plasma CVD method at this time may be dissolved in the alkali solution. .

In particular, the low-refractive index layer in the laminate of the antireflection film is often used as the outermost layer of the laminate, and therefore, it is in particular dissolved because it is in direct contact with an alkaline solution during alkali treatment. There were many.

In order to solve such a problem, a protective film is adhered to the outermost layer of the laminate at the time of alkali treatment, but this is not a fundamental solution and the protective film concerned is also present. Since it is necessary to attach and detach, there is also a problem that the manufacturing process becomes complicated.

The present invention has been made in view of the above problems, and provides a silica layer having excellent chemical resistance even when formed by a plasma CVD method, and a reflection using the silica layer. The main purpose is to provide a prevention film.

[0012]

In order to achieve the above object, the present invention is formed by the plasma CVD method in claim 1, and has a refractive index of 1.40 to 1.46 (λ =
550 nm) and 2800 to 3000 cm ^-1
Absorption by C-H stretching vibration at 1,200 ~
Infrared absorption by Si-CH ₃ stretching vibration at 1400 cm ^-1 provides a silica layer, characterized in that each is 0.1 cm ^-1 or less.

According to the invention, the silica layer comprises a plasma C
It is formed by the VD method and has a refractive index of 1.40 to 1.
Since it is 46 (λ = 550 nm), the silica layer has excellent adhesion and a high formation rate. In addition, the silica layer has excellent optical properties and can efficiently prevent reflection of light, and can be used as a low refractive index layer in a laminate of antireflection films.

Further, C at 2800 to 3000 cm ^-1
Infrared absorption by -H stretching vibration and 1200-140
The infrared absorption due to the Si—CH ₃ stretching vibration at 0 cm ⁻¹ is 0.1 cm ⁻¹ or less, that is, the detection sensitivity or less, so that it is clear that the silica layer contains almost no organic component, As a result, plasma CVD
It is considered that the silica layer formed by the method has excellent chemical resistance.

In the first aspect of the invention, as described in the second aspect, it is preferable that the raw material used in the plasma CVD method is a Si alkoxide.

According to the present invention, since the silica layer described in claim 1 is formed by using the Si alkoxide as a raw material, the adhesion of the silica layer and the layer forming speed do not pose a problem. Further, since the silica layer of the present invention uses Si alkoxide as a raw material, the amount of organic components contained in the layer is small, and the silica layer can be excellent in chemical resistance.

In the invention described in claim 2, as described in claim 3, the Si alkoxide as the raw material is preferably tetramethoxysilane.

According to the present invention, since the Si alkoxide which is a raw material when forming the silica layer by the plasma CVD method is tetramethoxysilane, the silica layer of the present invention according to claim 1 is formed. In addition, since the tetramethoxysilane has a relatively high vapor pressure, it can be easily supplied into the apparatus and is relatively easy to obtain. Therefore, it is highly preferable as a raw material.

Further, in the present invention, as described in claim 4, a base material, a hard coat layer located on the base material, and a plurality of thin layers located on the hard coat layer are laminated. In the antireflection film having a laminate,
Provided is an antireflection film, characterized in that the silica layer according to any one of claims 1 to 3 is used as a low refractive index layer in the laminate.

According to the present invention, the antireflection film is a base material, a hard coat layer located on the base material, and a laminate formed by laminating a plurality of thin layers on the hard coat layer,
In the antireflection film having, since the silica layer according to any one of claims 1 to 3 is used as the low refractive index layer in the laminate,
An antireflection film utilizing the characteristics of the silica layer of the present invention as described above can be provided. That is, since the silica layer in the laminate of the antireflection film of the present invention has excellent chemical resistance, the silica layer does not dissolve even in the alkali treatment performed when producing the antireflection film. Therefore, it is possible to manufacture an antireflection film without using a protective layer or the like, and as a result, it is possible to improve the yield.

In the antireflection film of the present invention described in claim 4, as described in claim 5, the layer structure of the laminate has a refractive index of 1.55 from the hard coat layer side.
A medium refractive index layer having a refractive index of 1.80 or more (λ = 550 nm), a high refractive index layer having a refractive index of 1.80 or more (λ = 550 nm),
The silica layer as the low refractive index layer according to any one of claims 1 to 3 is preferable.

Further, in the antireflection film of the present invention as described in claim 4, as described in claim 6, the layer structure of the laminate has a refractive index of 1.
A high refractive index layer having a refractive index of 80 or more (λ = 550 nm), a silica layer serving as the low refractive index layer according to claim 1 or 2, a high refractive index layer having a refractive index of 1.80 or more (λ = 550 nm), The silica layer as the low refractive index layer according to any one of claims 1 to 3 is preferable.

When the layered structure of the laminate has the above-mentioned structure, the reflection of light can be efficiently prevented by the interaction of the refractive indexes of the thin layers constituting the laminate.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The silica layer of the present invention and the antireflection film using the silica layer are specifically described below.

[1] Silica Layer The silica layer of the present invention has the features listed below. (1) It is formed by the plasma CVD method. (2) Refractive index 1.40 to 1.46 (λ = 550 nm)
Is. (3) C-H stretching vibration infrared absorption by at 2800 to 3000 cm ^-1, and S in 1200～1400Cm ^-1
Infrared absorption due to i-CH ₃ stretching vibration is 0.1 each
cm ^-1 or less.

The features (1) to (3) above will be specifically described.

Regarding the above feature (1), the silica layer of the present invention is characterized by being formed by the plasma CVD method.

In the plasma CVD method, atomic or molecular radical species are generated by adhering to a solid surface by plasma generation in a reaction chamber into which a predetermined gas is introduced, and in many cases, volatile molecules are further converted by surface reaction. It is a layering method that utilizes the phenomenon of being released and taken into the solid surface.
By forming the silica layer of the present invention using the plasma CVD method, the silica layer can be efficiently formed. Further, in the plasma CVD method, a capacitively coupled plasma CVD method and an inductively coupled plasma CV are used depending on a difference in a method of applying electric power used to generate plasma.
There are two types of D method, but in the present invention, either plasma CVD method can be used.

Further, when the silica layer is formed by the plasma CVD method, the adhesion and the formation rate of the silica layer do not pose a problem. Furthermore, conventional plasma CVD
In the silica layer formed by the method, chemical resistance may be a problem, but since the silica layer of the present invention also has the following characteristics (2) and (3),
Chemical resistance does not matter.

The plasma CVD apparatus used in the present invention is not particularly limited as long as it can control the temperature of a substrate such as a polymer film, and the power supply frequency and the plasma generation method are not particularly limited. Absent. A method of forming the silica layer of the present invention on the substrate using such a plasma CVD apparatus will be described with reference to FIG. In the following description, a web-shaped polymer film is used as the base material.

First, a web-like polymer film 1 as a substrate is unwound from a substrate unwinding section 2 and introduced into a plasma CVD reaction chamber 4 in a vacuum container 3. The entire reaction container 3 is evacuated by the vacuum pump 5.
At the same time, the raw material gas and the oxygen gas are supplied to the reaction chamber 4 from the raw material gas inlet 6 at a specified flow rate, and the inside of the reaction chamber 4 is always filled with these gases at a constant pressure. The raw material gas will be described later.

Next, the material is unwound from the base material unwinding section 2,
The polymer film 1 introduced into the reaction chamber 4 is wound around the layering drum 8 via the reversing roll 7 to form the layering drum 8
It is sent in the direction of the reversing roll 7 ', in synchronization with the rotation of. At this time, the temperature of the layering drum 8 can be controlled, and at this time, the surface temperature of the polymer film 1 and the surface temperature of the layering drum 8 are substantially equal. Therefore, the surface temperature of the polymer film 1 on which silica is deposited during plasma CVD, that is, the deposition temperature of plasma CVD can be controlled arbitrarily. In this example, the layering temperature when the silica layer of the present invention is layered on the polymer film 1 by plasma CVD is indicated by the surface temperature of the layering drum 8 at that time.

An RF voltage is applied from the power source 10 between the electrode 9 and the layering drum 8. At this time, the frequency of the power supply is not limited to radio waves, and it is possible to use an appropriate frequency from direct current to microwave. Then, by applying an RF voltage between the electrode 9 and the layering drum 8, plasma 11 is generated around these electrodes. Then, the raw material gas and the oxygen gas react in the plasma 11 to generate silica, which is deposited on the polymer film 1 wound around the layering drum 8 to form the silica layer 12. After that, the polymer film 1 having the silica layer 12 formed on the surface passes through the reversing roll 7 ′ and then the base material winding portion 2 ′.
Is wound up in.

As described above, in the present invention, the silica produced by the chemical reaction of the raw material gas and the oxygen gas by the plasma 11 is deposited on the polymer film 1 cooled by the stratifying drum 8 to an appropriate temperature. Then, since the silica layer is formed, it is possible to form the silica layer 12 of the present invention without exposing the polymer film 1 to high temperature and stretching, deforming or curling. Further, in the plasma CVD method of the present invention, the refractive index, layer thickness, etc. of the silica layer 12 to be formed can be controlled over a wide range by controlling the flow rate and pressure of the raw material gas, the discharge conditions, and the feed speed of the polymer film 1. You can

Here, the source gas for forming the silica layer of the present invention using the plasma CVD apparatus as described above will be explained.

The source gas that can be suitably used when forming the silica layer of the present invention is Si alkoxide. More specifically, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, di-t-butoxydiacetoxysilane, triethoxysilane, tripropoxysilane and the like can be mentioned. Since such a Si alkoxide contains many O atoms in the raw material, it efficiently promotes the oxidation of Si, C, and H in the raw material. Therefore, in the formed layer, C--H and Si--
This is because there is a feature that it is difficult for organic components such as CH ₃ to be mixed.

Of these Si alkoxides, tetramethoxysilane is particularly preferable when the silica layer of the present invention is formed by the plasma CVD apparatus as described above. Tetramethoxysilane contains a large amount of O atoms in the raw material, and the C-H bond in the raw material is particularly small.
This is because a layer containing no organic component can be formed more easily.

As described above, by forming the silica layer with the plasma CVD apparatus using the Si alkoxide, particularly tetramethoxysilane as the source gas, the organic component contained in the silica layer can be reduced, and as a result, It can be a thin layer having excellent chemical resistance.

Regarding the feature (2), the silica layer of the present invention has a refractive index of 1.40 to 1.46.
It is characterized by being

The silica layer of the present invention is an antireflection film having a substrate, a hard coat layer, and a laminate,
Since the main purpose is to use as a low refractive index layer in the laminate, the smaller the refractive index, the better, if the refractive index is within the range, the silica layer of the present invention has a low refractive index of the laminate. It can be preferably used as a layer.

Regarding the characteristic of (3), in the silica layer of the present invention, it is 2800 to 3000 cm.
Absorption by C-H stretching vibration at ^-1 and 1200
Infrared absorption by Si-CH ₃ stretching vibration at ～1400Cm ^-1 is 0.1 cm ^-1 or less, it is characterized in that less that is the detection sensitivity.

The infrared absorption by C-H stretching vibration at 2800 to 3000 cm ^-1, and 1200～1400Cm ^-1
Infrared absorption by Si-CH ₃ stretching vibration at 0.1c
The fact that it is m ⁻¹ or less means that there is almost no C—H bond or Si—CH 3 bond in the silica layer. That is, it is considered that the silica layer of the present invention does not contain a carbon compound (organic substance), and is therefore considered to have excellent chemical resistance.

Here, the infrared absorption is measured by a known IR spectrum transmission method, and the value of ∫ (α / f) df in the infrared absorption of each stretching vibration is calculated (α: Absorption coefficient, f: frequency).

[2] Antireflection Film Next, an antireflection film using the above-mentioned silica layer will be described. As shown in FIG. 2, the antireflection film 21 of the present invention includes a base material 22, a hard coat layer 23 located on the base material 22, a hard coat layer 23, and a plurality of thin layers (25 to 25). 27) is laminated. The laminated body 24 is characterized in that the above-mentioned silica layer of the present invention is used as a low refractive index layer.

As described above, by using the low refractive index layer in the thin layers forming the laminate 24 as the silica layer of the present invention, the refractive index of the silica layer of the present invention is 1.40 to 1.46.
Since (λ = 550 nm), it can be used as a sufficiently low-refractive index layer even in the laminate 24, and the silica layer of the present invention is resistant even when formed by the plasma CVD method. Since it has chemical properties, the silica layer will not dissolve even when subjected to alkali treatment.

Below, each of the thin layers (low refractive index layer 27, medium refractive index layer 25, high refractive index) constituting the base material 22, the hard coat layer 23, and the laminate 24 constituting the antireflection film 21 of the present invention. The rate layers 26) and the layer structure of the laminate 24 will be described.

[2-1] Substrate First, the base material 22 will be described.

In the antireflection film 21 of the present invention,
The base material 22 is a base of the antireflection film 21. The base material 22 is not particularly limited as long as it is a polymer film transparent in the visible light region. Examples of the polymer film include triacetyl cellulose film, diacetyl cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic film, polyurethane film, polyester film, polycarbonate film, polysulfone film, polyether. Examples thereof include a film, a trimethylpentene film, a polyetherketone film, an acrylonitrile film, a methacrylonitrile film and the like. Furthermore, a colorless film can be used more preferably. Among them, a uniaxially or biaxially stretched polyester film is preferably used because it has excellent transparency and heat resistance, and a polyethylene terephthalate (PET) film is particularly preferable. Triacetyl cellulose is also preferably used because it has no optical anisotropy. The thickness of the polymer film is preferably about 6 to 188 μm.

[2-2] Hard Coat Layer Next, the hard coat layer 23 will be described. In the antireflection film 21 of the present invention, the hard coat layer 23
Is a layer formed for the purpose of giving strength to the antireflection film 21.

The material for forming the hard coat layer 23 in the antireflection film 21 in the present invention is a material which is transparent in the visible light region like the base material 22 and gives the antireflection film 21 strength. It is necessary to be able to
It is preferable that the pencil altitude test shown by ISK5400 shows an altitude of H or higher.

Specifically, it is preferable to use a thermosetting resin and / or an ionizing radiation curable resin (these may be collectively referred to as a reaction curable resin in the present invention), and more specifically. Has an acrylate-based functional group, for example, relatively low molecular weight polyester, polyether, acrylic resin, epoxy resin, polyurethane, alkyd resin, spiro acetal resin, polybutadiene, polythiol polyene resin, polyhydric alcohol, etc. An oligomer or prepolymer such as a (meth) acrylate of a polyfunctional compound (hereinafter, acrylate and methacrylate are referred to as (meth) acrylate in the present specification) and ethyl (meth) acrylate which is a reactive diluent, Ethylhexyl (meth) acrylate, styrene, vinyltoluene, Monofunctional monomers such as vinylpyrrolidone and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, penta Erythritol bird (meta)
Acrylate, dipentaerythritol hexa (meth)
Those containing a relatively large amount of acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, etc. are used.

Further, when the above-mentioned ionizing radiation curable resin is used as an ultraviolet curable resin, photopolymerization initiators such as acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime can be used as photopolymerization initiators. It is preferable to use a mixture of esters, thioxanthones, and n-butylamine, triethylamine, tri-n-butylphosphine, etc. as photosensitizers.

The above ionizing radiation curable resin contains a reactive organosilicon compound represented by the general formula RmSi (OR ') n (wherein R and R'represent an alkyl group having 1 to 10 carbon atoms, m + n = 4, and m and n are each integers.). Examples of such a silicon compound include tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-silane. Butoxysilane, tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-
Butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane,
Examples thereof include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, methyldimethoxysilane, methyldiethoxysilane, and hexyltrimethoxysilane.

The layer thickness of the hard coat layer 23 is
It is usually in the range of 1 to 30 μm, and the manufacturing method thereof may be a usual coating method, and is not particularly limited.

[2-3] Laminate The laminate 24 in the antireflection film 21 of the present invention is
It is formed by laminating thin layers having different optical characteristics, and the laminated body 24 as a whole is configured to effectively prevent reflection due to the optical characteristics (especially refractive index) of each thin layer and the layer structure. There is something.

Usually, the thin layers constituting the laminated body 24 are roughly classified into a low refractive index layer, a medium refractive index layer and a high refractive index layer according to the refractive index thereof. Here, in the present invention, the low refractive index layer, the medium refractive index layer, and the high refractive index layer, when the thin layers constituting the laminate 24 are relatively compared by the respective refractive index, It is a name to distinguish each thin layer, a layer with a relatively high refractive index is a high refractive index layer,
A layer having a relatively low refractive index is a low refractive index layer, and a layer having a refractive index intermediate between the high refractive index layer and the low refractive index layer is a medium refractive index layer. Generally, a refractive index of 1.80 or more is a high refractive index layer, a refractive index of 1.55 or more and less than 1.80 is a medium refractive index layer, 1.
In many cases, a layer having a refractive index of less than 55 is a low refractive index layer. Therefore, also in the present invention, a layer having a refractive index of 1.80 or more is a high refractive index layer, 1.
55 or more and less than 1.80 are medium refractive index layers, and less than 1.55 are low refractive index layers. Then, since the silica layer of the present invention described above has a refractive index of 1.40 to 1.46, it can be said that it sufficiently functions as a low refractive index layer.

Hereinafter, each thin layer will be described in detail.

Low Refractive Index Layer In the antireflection film 1 of the present invention, the low refractive index layer (2
7) is the silica layer of the present invention having the above three characteristics. Whereas the refractive index of the low refractive index layer in an ordinary antireflection film is less than 1.55 (λ = 550 nm), the silica layer of the present invention has a refractive index of 1.40 to 1.40.
Since it is 1.46 (λ = 550 nm), it can be used as a sufficiently low refractive index layer.

In the antireflection film 1 of the present invention,
The position of the low refractive index layer (27) in the laminate 24 is not particularly limited, but the low refractive index layer (27) is usually the outermost layer (hard layer) of the laminate 24 as shown in FIG. It is preferably used on the side opposite to the coat layer 23).

The layer thickness of the silica layer as such a low refractive index layer is not particularly limited, but is 10 to 1000 n.
It is preferably m, and particularly preferably in the range of 50 to 150 nm. When the layer thickness is smaller than the above range, the antireflection effect may not be exerted, and when the layer thickness is larger than the above range, the entire layer may become brittle and may lack formability. .

Middle refractive index layer Next, the medium refractive index layer will be described.

In the antireflection film 1 of the present invention, the medium refractive index layer (25) is one of the thin layers forming the laminate 23, and its refractive index is 1.55 or more and 1.80. Is less than a thin layer. The medium refractive index layer (25) having such a refractive index is a thin layer used to enhance the antireflection function, and is not necessarily a thin layer required in the laminate 24.
The position where the medium refractive index layer is provided is not particularly limited, and it may be provided at any position as long as the antireflection function is improved in the entire laminate 24. However, when the silica layer (27) as the low refractive index layer and the high refractive index layer (26) are in contact with each other, reflection of light can be efficiently prevented (see FIG. 2). The middle refractive index layer (25) is preferably provided in a portion other than between the silica layer as the low refractive index layer and the high refractive index layer, for example, below the high refractive index layer as shown in FIG.

In the present invention, the thin layer that can be used as the medium refractive index layer (25) has transparency in the visible light region and has a refractive index of 1.55 or more and less than 1.80 (λ =
It is not particularly limited as long as it is a thin layer having a thickness of 550 nm), but in the present invention, it is a thin layer that can be formed by a plasma CVD method like the silica layer as the low refractive index layer. Is particularly preferred. This is because by using the plasma CVD apparatus described later, the medium refractive index layer can be formed simultaneously with the silica layer as the low refractive index layer.

As such a medium refractive index layer (25),
For example, carbon-containing silicon oxide layer, Al ₂ O ₃ , Si
A material in which fine particles of N, SiON, ZrO ₂ , SiO ₂ , or ZnO ₂ are dispersed in a silicon oxide layer is preferably used. By mixing the above-mentioned fine particles in the silicon oxide layer, the refractive index thereof is 1.55 or more and less than 1.80 (λ = 55
It is relatively easy to set the thickness to 0 nm), and the silicon oxide layer is excellent in wet heat resistance even when formed by the plasma CVD method, and a thin layer having a stable refractive index can be obtained. Since the plasma CVD method has a high thin layer forming speed, the cost of manufacturing the antireflection film can be improved.

The layer thickness of the medium refractive index layer is not particularly limited, but is preferably 5 to 300 nm.
˜150 nm is particularly preferred. This is because if the layer thickness is less than 5 nm, the antireflection effect can hardly be expected, and conversely, if the layer thickness is greater than 300 nm, base material deformation or layer peeling due to layer stress may occur. Because.

High refractive index layer Next, the high refractive index layer will be described.

In the antireflection film 1 of the present invention, the high refractive index layer (26) is one of the thin layers forming the laminate 23 and has a refractive index of 1.80 or more (λ = 550.
nm). Combined with the low refractive index layer and the medium refractive index layer described above, the refractive index is 1.80 or more (λ = 550 nm)
By providing such a thin layer in the laminated body 24, it is possible to efficiently prevent the reflection of light due to the difference in the respective refractive indexes. In the antireflection film 21 of the present invention, the position of the high refractive index layer (26) in the laminate 24 is not particularly limited, but as described above,
It is preferable to provide the low refractive index layer (27) and the high refractive index layer (26) below the low refractive index layer, because it is possible to prevent light reflection efficiently when they are in contact with each other.

In the present invention, the thin layer that can be used as the high refractive index layer (26) has transparency in the visible light range and has a refractive index of 1.80 or more (λ = 550 nm).
Although it is not particularly limited as long as it is a thin layer that is a thin layer that can be formed by a plasma CVD method like the silica layer or the medium refractive index layer as the low refractive index layer in the present invention. Particularly preferred is a layer. This is because by using a plasma CVD apparatus described later, a high refractive index layer can be formed at the same time as a silica layer as a low refractive index layer or a medium refractive index layer.

As such a high refractive index layer (26),
For example, a titanium oxide layer, an ITO (indium tin oxide) layer, a zinc oxide layer, a tin oxide layer, a silicon carbide layer, a silicon oxycarbide layer, a silicon nitride layer, a niobium oxide layer, a tantalum oxide layer, a hafnium oxide layer, Etc. can be used suitably.

As a method for forming the high refractive index layer (26), a sputtering method, a vacuum deposition method, or an ion plating method can be used other than the plasma CVD method.

The layer thickness of such a high refractive index layer is not particularly limited, but is preferably 5 to 300 nm, particularly preferably 10 to 150 nm. This is because if the layer thickness is less than 5 nm, the antireflection effect can hardly be expected, and conversely if the layer thickness is greater than 300 nm,
This is because the base material may be deformed or the layer may peel due to the stress of the layer.

[2-4] Layer Structure The layer structure of the laminate 4 in the antireflection film 1 of the present invention will be specifically described with reference to the drawings.

In the antireflection film 1 of the present invention,
The silica layer of the present invention described above may be used as the low refractive index layer, and the layer structure is not particularly limited.

However, as the laminated body, as shown in FIG. 2, the medium refractive index layer 2 is formed from the hard coat layer 23 side.
5, the high refractive index layer 26 and the low refractive index layer 27 are preferably laminated in this order. By stacking in this way,
The low refractive index layer 27 can effectively prevent the reflection of light due to the difference in the refractive index of each thin layer, and as the low refractive index layer 27, the silica layer of the present invention having the characteristics (1) to (3) described above. Therefore, even if the low refractive index layer is used as the outermost layer for alkali treatment, the silica layer does not dissolve.

A laminated body 4'as shown in FIG. 3 is also preferable as the antireflection film of the present invention. As shown in FIG. 3, the antireflection effect is improved by alternately laminating the high refractive index layer 26 ′ and the silica layer of the present invention as the low refractive index layer 27 ′ twice from the hard coat layer 23 side. Because you can do it.

FIG. 4 is a schematic view of a plasma CVD apparatus which can be suitably used when forming the antireflection film of the present invention. The plasma CVD apparatus 40 is a capacitively coupled plasma CVD apparatus, and its basic configuration is the same as that of the plasma CVD apparatus shown in FIG.

The web-shaped polymer film 41 is unwound from the substrate unwinding part 42 and introduced into the reaction chambers (a, b, c) in the vacuum container 43. Then, a predetermined layer is formed on the layering drum 44 in the reaction chamber and is wound by the base material winding section 46.

A plurality of (3) plasma CVD devices 40 are provided.
The reaction chambers (a, b, c) are separated from each other by the isolation wall 45. Here, for convenience of the following description, the three reaction chambers are referred to as a reaction chamber a, a reaction chamber b, and a reaction chamber c from the right side. The electrode plates a1, b1 and c are respectively provided in the reaction chambers.
1 and raw material gas introduction ports a2, b2, and c2 are installed. Each reaction chamber (a, b, c) is installed along the outer periphery of the layering drum 44. This is because the polymer film 1 on which the antireflection laminate is formed is inserted into the reaction chamber in synchronization with the layering drum 44, and forms the layered product on the layering drum. This is because each layer can be continuously laminated by arranging the layers.

According to the plasma CVD apparatus as described above, it is possible to form the layers independently in each reaction chamber by changing the source gas introduced into each reaction chamber.

For example, in the case of manufacturing the antireflection film shown in FIG. 2, a hard coat layer is first formed on a PET film as a base material by a conventional wet coating, and then a medium refractive index layer, High refractive index layer,
And the silica layer of the present invention can be formed by the plasma CVD apparatus. In this case, a gas containing silicon is introduced into the reaction chamber a (when a silica layer is used for the medium refractive index layer), and a gas containing an organic titanium compound is introduced into the reaction chamber b to form the silica layer of the present invention. By introducing, for example, tetramethoxysilane into the forming reaction chamber c, the polymer film 41 passes through the layering drum 44 and the base material winding portion 46.
It becomes possible to form an antireflection film in which the medium refractive index layer, the high refractive index layer and the silica layer of the present invention are formed on the polymer film 41 before being wound up.

Materials usable as the organic titanium compound used for forming the high refractive index layer in the antireflection film of the present invention include Ti (i-OC ₃ H ₇ ) ₄
(Titanium tetra i-propoxide), Ti (OCH ₃ ) ₄
(Titanium tetramethoxide), Ti (OC ₂ H ₅ ) ₄ (Titanium tetraethoxide), Ti (n-OC ₃ H ₇ ) ₄ (Titanium tetra n-propoxide), Ti (n-OC ₄ H ₉ ).
₄ (titanium tetra-n-butoxide), Ti (t-OC ₄ H
₉ ) Titanium alkoxide of ₄ (titanium tetra-t-butoxide) can be mentioned. Among them, Ti (i-OC ₃ H ₇ )
₄ (titanium tetra i-propoxide), Ti (t-OC ₄
H _{9) 4} (titanium tetra t- butoxide) is preferred because of high vapor pressure.

The present invention is not limited to the antireflection film and the manufacturing method thereof described above. The above-described embodiment is an exemplification, has substantially the same configuration as the technical scope described in the claims of the present invention, and has any similar effects. It is included in the technical scope of the present invention.

[0083]

EXAMPLES The present invention will be described in more detail by way of examples.

Example 1 As an example of the present invention, a silica layer was formed on a hard coat layer formed on a substrate by using the apparatus shown in FIG. The conditions for forming the silica layer are shown below.

Source gas: tetramethoxysilane gas, oxygen gas Plasma generation means: 40 kHz RF wave Base material: Triacetyl cellulose (Fujitac T80UN
Z: Fuji Photo Film, thickness: 80 μm) was used. Hard coat layer: ionizing radiation curable resin (PETD-3
1: Daiichi Seika Kogyo Co., Ltd. was applied so that the dry thickness would be about 6 μm, and the acceleration voltage was 175 kV and the irradiation dose was 10
It was cured with an electron beam of Mrad, and a hard coat layer of about 6 μm was used.

A silica layer was formed on the substrate under the above conditions. When the refractive index of the silica layer was measured, the refractive index was 1.42 (λ = 550 nm). From this result,
It was found that the silica layer of Example 1 of the present invention was excellent in optical properties and sufficiently functions as a body refractive index layer of the laminate in the antireflection film.

In order to examine the composition of the silica layer (carbon content in the layer), IR measurement was carried out. The result of IR measurement is shown in FIG. 5 (thick line). As shown in FIG. 5 (thick line),
The silica layer of Example 1 of the present invention is 2800-3000c.
Infrared absorption by CH stretching vibration at m ^-1 , and 120
It is clear that the infrared absorption due to the Si—CH ₃ stretching vibration at ⁰ to 1400 cm ⁻¹ is 0.1 cm ⁻¹ or less, that is, the detection sensitivity or less. From this result, it was found that the silica layer of Example 1 of the present invention contained almost no C—H bond and Si—CH ₃ bond, and it can be said that the silica layer is a thin layer having a small organic component.

Further, in order to examine the chemical resistance of the silica layer of Example 1 of the present invention, the silica layer was impregnated with a potassium hydroxide (2N) solution heated to 60 ° C. for 1 minute, and The state of the silica layer was observed. As a result, there was no trace of dissolution in the silica layer, which was exactly the same as in the chemical resistance test.

For the measurement of the optical characteristics (refractive index), an ultraviolet-visible spectroscopic analyzer and an ellipsometer were used.
An infrared absorption spectroscopy analyzer was used for IR measurement.

Comparative Example 1 As a comparative example 1 of the silica layer of the present invention (Example 1), the apparatus of FIG. 1 was used to form a silica layer on the hard coat layer formed on the substrate. The conditions for forming the silica layer are shown below.

Source gas: hexamethyldisiloxane, oxygen gas plasma generation means: RF wave at 40 kHz Base material: triacetyl cellulose (Fujitac T80UN
Z: Fuji Photo Film, thickness: 80 μm) was used. Hard coat layer: ionizing radiation curable resin (PETD-3
1: Daiichi Seika Kogyo Co., Ltd. was applied so that the dry thickness would be about 6 μm, and the acceleration voltage was 175 kV and the irradiation dose was 10
It was cured with an electron beam of Mrad, and a hard coat layer of about 6 μm was used.

A silica layer was formed on the substrate under the above conditions. When the refractive index of the silica layer was measured, the refractive index was 1.46 (λ = 550 nm).

Further, IR measurement was carried out in order to investigate the composition of the silica layer (carbon content in the layer). The result of IR measurement is shown in FIG. 5 (thin line). As shown in Fig. 5 (thin line),
The silica layer of Comparative Example 1 absorbs infrared rays by C—H stretching vibration at 2800 to 3000 cm ⁻¹ , and 1200 to 14
Peaks due to infrared absorption due to Si—CH ₃ stretching vibration at 00 cm ⁻¹ appear, 0.22 cm each.
^-1 , 1.1 cm ^-1 . From this result, it was found that the silica layer of Comparative Example 1 contains both C—H bond and Si—CH ₃ bond, and can be said to be a thin layer having a high carbon content.

Further, in order to examine the chemical resistance of the silica layer of Comparative Example 1, potassium hydroxide (2
N) The solution was impregnated with the silica layer for 1 minute, and then the state of the silica layer was observed. As a result, a trace of dissolution was confirmed on the surface of the silica layer.

The apparatus used for each measurement was the same as in Example 1 above.
Is the same as.

Example 2 FIG. 4 shows Example 2 of the present invention.
2 was used to form the antireflection film shown in FIG. The conditions for forming the antireflection film are shown below.

In the laminate of the antireflection film of the present invention shown in FIG. 2, a silicon oxide layer is formed in the reaction chamber a as a medium refractive index layer, and a titanium oxide layer is formed in the reaction chamber b as a high refractive index layer. As a low refractive index layer, the silica layer of the present invention was formed in the reaction chamber c (see FIG. 4).

[0098] Raw material gas: (reaction chamber a) hexamethyldisiloxane gas, oxygen gas           (Reaction chamber b) Titanium tetraisopropoxide gas, oxygen gas           (Reaction chamber c) tetramethoxysilane gas, oxygen gas Plasma generating means: 40 kHz RF wave Substrate: Triacetyl cellulose (TAC) film Hard coat layer: electron beam curable acrylic hard coat

The antireflection film of the present invention was formed under the above conditions. The reflection spectrum of the antireflection film is shown in FIG. As is clear from FIG. 6, the antireflection film of the example of the present invention was found to have an excellent antireflection function. In addition, although alkali treatment was carried out when the antireflection film was formed, no trace of dissolution was observed on the surface of the silica layer of the present invention, which is the outermost layer, and therefore it can be said that it has excellent chemical resistance.

[0100]

The silica layer of the present invention is formed by the plasma CVD method and has a refractive index of 1.40 to 1.46.
Since (λ = 550 nm), the silica layer has excellent adhesion and a high formation rate. In addition, the silica layer has excellent optical properties and can efficiently prevent reflection of light, and can be used as a low refractive index layer in a laminate of antireflection films.

Further, C at 2800 to 3000 cm ^-1
Infrared absorption by -H stretching vibration and 1200-140
Since the infrared absorptions due to the Si—CH ₃ stretching vibration at 0 cm ⁻¹ are each 0.1 cm ⁻¹ or less, it is clear that the silica layer contains almost no organic component containing a C—H bond. As a result, it is considered that the silica layer formed by the plasma CVD method has excellent chemical resistance.

According to the antireflection film using the silica layer as the low refractive index layer, since the low refractive index layer forming the laminate has the above-mentioned characteristics, plasma CVD is performed.
All the laminates can be formed by the method, and the laminates are not dissolved even by the alkali treatment performed when forming the antireflection film.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a plasma CVD apparatus used when forming a silica layer of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the antireflection film of the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of the antireflection film of the present invention.

FIG. 4 is a schematic cross-sectional view of a plasma CVD apparatus used when manufacturing the antireflection film of the present invention.

5 is an IR chart of the silica layer of Example 1 and the silica layer of Comparative Example 1. FIG.

6 is a reflection spectrum of the antireflection film of Example 2. FIG.

[Explanation of symbols] 21, 21 '... Antireflection film 22, 22 '... Base material 23, 23 '... Hard coat layer 24, 24 '... laminated body 25 ... Middle refractive index layer 26, 26 '... High refractive index layer 27, 27 '... Low refractive index layer (silica layer)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F100 AA20C AT00A BA03 BA05                       BA07 BA10A BA10C EJ53                       EJ61C GB41 JD12C JK12B                       JN18C JN18D JN18E JN30                       YY00C YY00D YY00E                 4K030 AA06 AA11 BA44 CA07 CA12                       DA01 FA01 LA18

Claims (6)

[Claims] 1. Formed by plasma CVD method
With a refractive index of 1.40 to 1.46 (λ = 550 nm)
Yes, and 2800-3000 cm^-1C-H expansion and contraction
Infrared absorption by vibration, and 1200-1400cm^-1
Si-CH at ₃Infrared absorption due to stretching vibration is
0.1 cm^-1A silica layer characterized by being: 2. The silica layer according to claim 1, wherein the raw material used when the plasma CVD method is used is a Si alkoxide. 3. The Si alkoxide as the raw material,
It is tetramethoxysilane, It is characterized by the above-mentioned.
The silica layer according to 1. 4. An antireflection film comprising: a base material; a hard coat layer located on the base material; and a laminate formed on the hard coat layer and having a plurality of thin layers laminated together. An antireflection film, wherein the silica layer according to any one of claims 1 to 3 is used as the low refractive index layer in the body. 5. The antireflection film according to claim 4, wherein the layered structure of the laminate has a refractive index of 1.55 or more and less than 1.80 (λ = 550 nm) from the hard coat layer side.
A medium refractive index layer, a high refractive index layer having a refractive index of 1.80 or more (λ = 550 nm), and a silica layer as a low refractive index layer according to any one of claims 1 to 3. An antireflection film characterized by being present. 6. The antireflection film according to claim 4, wherein the layered structure of the laminate is a high refractive index layer having a refractive index of 1.80 or more (λ = 550 nm) from the hard coat layer side, A silica layer as the low refractive index layer according to claim 1 or 2, a high refractive index layer having a refractive index of 1.80 or more (λ = 550 nm), or any one of claims 1 to 3. A silica layer as the low refractive index layer described in 1., An antireflection film.