JP2003337203A - Antireflection film and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film having a low average reflectance, a pale color in reflection and excellent film hardness by using normal pressure plasma CVD and to provide a method of manufacturing the film. <P>SOLUTION: In the method of manufacturing an antireflection film using discharge plasma, the method includes: a first process of supplying a gaseous source material containing a high refractive index material to deposit a high refractive index layer on a substrate film while keeping part of the reactivity; and a second process of supplying a gaseous source material containing a low refractive index material onto the high refractive index material layer to deposit a layer having an intermediate refractive index between the high refractive index and a low refractive index. The antireflection film has successively deposited layers of a high refractive index layer and a low refractive index layer without having an interface on the substrate film. The high refractive index layer has 1.65 to 1.75 refractive index at 550 nm wavelength and 140 to 200 nm optical film thickness. The low refractive index layer shows 550 to 600 nm minimum reflection wavelength. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film and a method for producing the same, more specifically, it is suitable for flat panel displays such as flat panel televisions produced by using atmospheric pressure plasma and has a small average reflectance. The present invention relates to an antireflection film having a light color at the time of reflection and excellent film hardness, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, an antireflection film has been manufactured mainly by a vapor deposition method or a sputtering method, but in recent years, atmospheric pressure plasma has been used from the viewpoint of economical efficiency of production equipment, production operability and the like. A continuous film forming method of thin films such as silicon dioxide and titanium dioxide has come to be used. For example, in Japanese Unexamined Patent Application Publication No. 11-241165, as shown in FIG. 1, a roll electrode 10 and a curved electrode 20 having a coaxial rotating surface as a surface are arranged so as to face each other with a constant distance from the surface of the roll electrode 10. A continuous film-forming apparatus provided with a discharge space 30 curved between the electrodes 10 and 20 at substantially equal intervals is used.
A mixed gas containing a reaction gas is supplied from one end of the above, and an exhaust device using the flow rate adjusting valve 40 and the vacuum pump 50 from the other end so that the mixed gas flow rate in the discharge space 30 becomes constant. A base material (not shown) running along the roll electrode 10 by applying a voltage between the electrodes 10 and 20 to adjust the temperature to cause plasma discharge.
A thin film was formed on top.

Recently, Japanese Unexamined Patent Publication No. 10-182745
In the publication, a coated type was proposed as an inexpensive antireflection film for large screens such as flat-screen televisions and plasma displays. This type of antireflection film has the advantage that the minimum reflectance itself does not become so low, but the reflectance at wavelengths other than the minimum reflection wavelength does not become very high, and the color of reflected light is light. However, normal pressure plasma CV
The conventional two-layer antireflection film manufactured by D
Although the lowest reflectance itself is considerably low, the reflectance of wavelengths other than the lowest reflection wavelength is not so low, and there is a problem that the reflected light exhibits a considerably dark purple to blue-violet color.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention uses a normal pressure plasma CVD method to obtain a small average reflectance, a light color upon reflection, and a film hardness superior to a coating type. An object of the present invention is to provide a preventive film and a manufacturing method thereof.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that in a method for producing an antireflection film formed by laminating metal compound films by generating discharge plasma. First, a high refractive index layer is formed on the base film with some reactivity remaining,
The inventors have found that good results can be obtained by supplying a raw material gas containing a low refractive index material on top of this and performing discharge plasma treatment, and have completed the present invention.

That is, according to the first aspect of the present invention,
At least two different refractive indexes are formed on the base film by using discharge plasma generated by applying an electric field between the opposing electrodes in a source gas atmosphere containing a metal compound under a pressure near atmospheric pressure. In the method for producing an antireflection film for forming a metal compound film, by supplying a raw material gas containing a high refractive index material, by performing discharge plasma treatment,
A first step of forming a high refractive index layer on a substrate film while partially leaving the reactivity, and then supplying a source gas containing a low refractive index material on the high refractive index layer, and discharging. Provided is a method for producing an antireflection film, which comprises a second step of forming a layer having an intermediate refractive index between a high refractive index and a low refractive index by performing a plasma treatment.

According to the second aspect of the present invention, the first aspect
In the invention, the first step is to weaken the discharge power or increase the traveling speed of the base film in order to form the high refractive index layer in which a part of the reactivity remains. There is provided a method for producing an antireflection film, which comprises performing a discharge plasma treatment under conditions.

According to the third aspect of the present invention, the first aspect
In the invention described above, the high refractive index layer is ZrO ₂ , Ti
O ₂ , SnO ₂ , In ₂ O ₃ , ITO, Ta ₂ O ₅ , ZnO,
There is provided a method for producing an antireflection film, which comprises at least one metal oxide having a large refractive index selected from HfO ₂ , CeO ₂ , Nb ₂ O ₅ , and Y ₂ O ₃ .

According to a fourth aspect of the present invention, the first aspect
In the invention of, the substrate film is polyethylene terephthalate, polyethylene naphthalate, polymethylmethacrylate, polycarbonate, regenerated cellulose, diacetyl cellulose, triacetyl cellulose,
It is characterized by being composed of a transparent resin selected from norbornene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyether sulfone, polyether ketone, polyethylene, polypropylene, polyimide, polyamide or poly 4-methylpentene 1. A method for manufacturing an antireflection film is provided.

According to a fifth aspect of the present invention, the first aspect
In the invention of, the raw material gas containing the low refractive index material,
Tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, diethoxydimethylsilane, tetramethylsilane, tetraethylsilane, tetraethoxysilane, dimethoxydimethylsilane, dimethylsilane, tetramethylsilane, Provided is a method for producing an antireflection film, which is one or more compounds selected from monosilane, silane, silane dichloride, or silane trichloride.

According to a sixth aspect of the present invention, the first aspect
In the invention, there is provided a method for producing an antireflection film, wherein the first step and the second step are continuously performed by separate discharge plasma processing apparatuses.

According to a seventh aspect of the present invention, there is provided an antireflection film comprising a base film, a high refractive index layer and a low refractive index layer which are sequentially laminated without an interface. The refractive index layer has a refractive index of 1.65 at a wavelength of 550 nm.
˜1.75, the optical film thickness is 140 to 200 nm, while the low refractive index layer has a minimum reflection wavelength of 550 to 600 nm.
An antireflection film is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The antireflection film of the present invention and the method for producing the same will be described in detail below for each item.

1. Pressure near atmospheric pressure In the continuous film forming method using atmospheric pressure plasma of the present invention, the pressure near atmospheric pressure means a pressure of 13300 to 106400 Pa, and among them, pressure adjustment is easy and the device configuration is easy 93100. It is preferable to set the pressure range to 103740 Pa.

2. Gas Atmosphere Containing Metal Compound In the present invention, the gas atmosphere containing a metal compound is a mixed gas atmosphere composed of a raw material gas, a reaction gas and a diluent gas, and each gas is described in detail in the subsequent paragraphs.

3. Base Film In the present invention, the base film is a film that serves as a base of an antireflection film, and its material is any material as long as it is excellent in transparency, lightness, mechanical strength, flexibility and the like. There may be, for example, polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polycarbonate, regenerated cellulose, diacetyl cellulose, triacetyl cellulose, norbornene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyether sulfone,
Polyetherketone, polyethylene, polypropylene,
Examples thereof include polyimide, polyamide, and poly-4-methylpentene 1, and polyethylene terephthalate and triacetyl cellulose are particularly preferable.

4. Metal Compound Film In the present invention, the metal compound film is a laminated film formed on the surface of a substrate film, is an oxide of a metal atom present in an organometallic compound as a raw material gas, and ZrO ₂ ,
TiO ₂ , SnO ₂ , In ₂ O ₃ , ITO, Ta ₂ O ₅ , Zn
O, HfO ₂ , CeO ₂ , Nb ₂ O ₅ , Y ₂ O ₃ , Al ₂ O ₃ ,
Examples are SiO ₂ and MgF ₂ .

5. High refractive index layer In the present invention, the high refractive index layer is the surface of the base film.
The formed high-refractive-index metal compound film, ZrO₂,
TiO₂, SnO₂, In₂O₃, ITO, Ta₂O _Five, Zn
O, HfO₂, CeO₂, Nb₂O_Five, Or Y₂O₃Etc. are examples
Especially TiO₂Is preferred. This high refractive index layer
Consists of raw material gas for high refractive index layer, reaction gas and diluent gas
The mixed gas reacts in the discharge plasma and the surface of the base film
Is formed.

6. High Refractive Index Layer with Partially Reactive Remaining In the present invention, the high refractive index layer with a partly reactive state supplies a source gas containing a low refractive index material on the high refractive index layer. When a layer having an intermediate refractive index between a high refractive index and a low refractive index is formed on the surface of the base film by performing discharge plasma treatment, the high refractive index layer is not partially reactive, It is necessary because the raw material gas containing the low refractive index material cannot react. In order to leave reactivity in the high refractive index layer, weakening the discharge plasma treatment when forming the high refractive index layer, specifically weakening the discharge power or increasing the running speed of the base film Well, this is explained in detail in a later paragraph.

7. Raw Material Gas In the present invention, the raw material gas is a main component of a mixed gas composed of the raw material gas, the reaction gas and the diluent gas, and reacts in discharge plasma to form a metal compound film. From the viewpoint of function, the metal compound film serves as a high refractive index layer, an intermediate refractive index layer or a low refractive index layer, and has a function of preventing reflection.

7.1 Raw Material Gas for High Refractive Index Metal Compound Film In the present invention, the raw material gas for a high refractive index metal compound film is ZrO ₂ , TiO ₂ , which is a high refractive index metal compound film,
SnO ₂ , In ₂ O ₃ , ITO, Ta ₂ O ₅ , ZnO, Hf
Z as a raw material for O ₂ , CeO ₂ , Nb ₂ O ₅ , Y ₂ O ₃ or the like
r, Ti, Sn, In, IT, Ta, Zn, Hf, C
Examples include hydrides, alkoxides, alkylates, hydroxides, halides of metals such as e, Nb, and Y.

For example, tetramethoxy titanium, tetraethoxy titanium, tetra-i-propoxy titanium, tetra-i-butoxy titanium, tetra-n-butoxy titanium,
Tetra-t-butoxy titanium, tetra-sec-butoxy titanium, tetraoctyl titanium, titanium chloride, tetradimethylamino titanium, titanium isopropoxide, titanium butoxide, tetramethyl tin, tetramethyl lead, acetylacetone tributoxy zirconium, dibutyl zinc, Examples include diethyl tellurium, dibutyl tin oxide, dimethyl zinc, dimethyl cadmium, dimethyl tellurium, tetra-n-butoxy zirconium, tatramethyl tin, triethyl indium, triethyl gallium, trimethyl indium, trimethyl gallium, n-butyl ethyl magnesium, monobutyl tin oxide. To be
These may be used alone or in combination of two or more.

7.2 Raw Material Gas for Low Refractive Index Metal Compound Film In the present invention, the raw material gas for a low refractive index metal compound film is Al ₂ O ₃ , Si which is a low refractive index metal compound film.
It is a hydride, an alkoxy compound, an alkyl compound, a hydroxide, a halide or the like of a metal such as Al, Si, Mg or F which is a raw material of O ₂ or MgF ₂ .

For example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, tetramethylsilane, tetraethylsilane, dimethylsilane, dimethoxydimethylsilane, diethoxydimethylsilane,
Tetramethylsilane, monosilane, disilane, dichlorosilane, trichlorosilane, carbon tetrafluoride (CF ₄ ), carbon hexafluoride (C ₂ F ₆ ), propylene hexafluoride (CF ₃ CFC)
F ₂ ), octafluorofluorobutane (C ₄ F ₈ ) and other fluorine-
Examples thereof include carbon compounds, halogen-carbon compounds such as carbon trifluoride trifluoride (CClF ₃ ), and reactive fluorine compounds such as fluorine-sulfur compounds such as sulfur hexafluoride (SF ₆ ). These may be used alone or in combination of two or more.

8. Reaction Gas In the present invention, the reaction gas is one component of a mixed gas consisting of a raw material gas, a reactive gas and a diluent gas, and reacts with the raw material gas in discharge plasma to produce a compound forming a target thin film, Alternatively, it facilitates its generation. For example, oxygen gas, ozone, water (water vapor), carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, aldehydes such as methanal and ethanal. Organic compounds containing oxygen elements such as
Examples thereof include nitrogen gas, ammonia, sulfur dioxide, sulfur trioxide and the like. These may be used alone or in combination of two or more. The content ratio of the reaction gas in the mixed gas is preferably 0 to 99.99% by volume.

9. Diluting Gas In the present invention, the diluting gas is one component of a mixed gas consisting of a raw material gas, a reaction gas and a diluting gas, and for controlling the degree of reaction between the raw material gas and the reaction gas and the properties of the inorganic thin film formed And examples thereof include helium, argon, neon, and nitrogen gas, which have low activity. These may be used alone or in combination of two or more. The content ratio of the diluent gas in the mixed gas is preferably 0 to 99.99% by volume.

10. Discharge plasma processing apparatus The discharge plasma processing apparatus for carrying out the continuous film forming method of the present invention is particularly limited as long as it can generate uniform discharge plasma in the mixed gas atmosphere described above under a pressure near atmospheric pressure. Although not included, for example, a discharge plasma generator having a counter electrode such as a parallel plate type, a cylinder facing flat plate type, a sphere facing flat plate type, a hyperboloid facing flat plate type, and a coaxial cylindrical type structure can be mentioned. Among them, as shown in FIG. 1, a roll electrode 10 and a curved electrode 20 having a coaxial cylindrical surface (concave surface) facing the surface of the roll electrode 10 at a constant interval.
Are arranged to face each other, and the roll electrode 10 and the curved surface electrode 2 are arranged.
It is particularly preferable to use a discharge plasma generation device including a counter electrode in which discharge spaces 30 that are curved at substantially equal intervals are formed between the discharge plasma generation device and the discharge electrodes. In this counter electrode, the roll electrode 10 and the curved electrode 20
The discharge space 30 formed between and becomes the film formation space.

The above-mentioned roll electrode is a columnar or cylindrical electrode, and the conductive material forming the electrode body is preferably a metal such as copper or aluminum, or an alloy / intermetallic compound such as stainless steel or brass. Etc.

The distance between the roll electrode and the curved electrode is not particularly limited as long as it is equal to or larger than the thickness of the thin film support material or base material formed by the discharge plasma treatment.
If it is too wide, the discharge will be in the form of lightning, and the uniformity of the discharge will be easily impaired. In addition, the support material or the base material may be greatly damaged, so that the thickness is preferably 5 mm or less. Further, (space between roll electrode and curved surface electrode) / (radius of roll electrode) is preferably 1/100 or less because the smaller the value, the better the uniformity of discharge.

It is preferable that at least one of the surface of the roll electrode and the curved electrode, particularly the surface of the curved electrode, is coated with a solid dielectric. In this way, when at least one of the roll electrode and the curved electrode is coated with a solid dielectric,
The film forming space is a space between the exposed electrode surface and the solid dielectric coating surface or a space between the solid dielectric coating surfaces.

Examples of solid dielectrics include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide and titanium dioxide, and complex oxides such as barium titanate. To be

The relative dielectric constant of the solid dielectric is preferably 10 or more. When the relative permittivity is 10 or more, a high-density discharge plasma can be generated at a low voltage, and surface treatment for a short time or high-speed front and back treatment can be performed, but when the relative permittivity is less than 10, It becomes difficult to perform such a surface treatment. The upper limit of the relative permittivity is not particularly limited, but a material that has been realized is about 18500.

The relative dielectric constant of the solid dielectric material is particularly preferably in the range of 10 to 100. Examples of such a solid dielectric include metal oxides such as zirconium dioxide (ZrO ₂ ), titanium dioxide (TiO ₂ ), barium titanate (Ba _2).
Examples thereof include complex oxides such as TiO ₄ ).

The titanic acid compound is known as a ferroelectric substance. In the case of TiO ₂ simple substance, the relative dielectric constant differs depending on the crystal structure, and in the rutile type crystal structure, the relative dielectric constant is about 80.

Also, Ba, Sr, Pb, Ca, Mg, Z
At least one selected from oxides of metals such as r and Ti
In the case of a compound with O ₂ , the relative dielectric constant is about 2,000 to 1
The relative permittivity can be changed depending on the purity and crystallinity.

On the other hand, when TiO ₂ alone is used, the composition changes drastically in a heating environment. For example, when heating in a reducing atmosphere,
The use environment is limited due to oxygen deficiency or the like, and in a normal film forming method, a thin film having a specific resistance of about 10 ⁴ Ω · cm is formed, and therefore, it is easy to shift to arc discharge due to voltage application, and caution is required. Therefore, TiO ₂ may better than alone was used by containing aluminum oxide (Al ₂ O _3), in particular, TiO _2: 5 to 50 wt%, Al ₂ O _3: 50
~ 95 wt% mixed metal oxide thin film, or Zr
It consists of a metal oxide thin film containing O ₂ and has a film thickness of 10 to 10.
The 1000 μm solid dielectric is thermally stable and
Relative permittivity is about 10-14, specific resistance is 10 ¹⁰ Ω · cm
It is more preferable because the arc discharge does not occur.

The solid dielectric may be in the form of a sheet or a film, but the thickness is preferably 0.05 to 4 mm. If it is too thick, a high voltage is required to generate discharge plasma, and if it is too thin, dielectric breakdown occurs when a voltage is applied and arc discharge occurs.

In the discharge plasma processing apparatus for carrying out the present invention, the roll electrode may be constructed so as to rotate in synchronization with the conveying speed of the substrate on which the inorganic thin film is formed. The method of rotating the roll electrode may be a method in which it is driven freely and is rotated in conjunction with the substrate, or a method in which it is rotated by a driving device such as a motor.

In the discharge plasma processing apparatus for carrying out the present invention, the gas introduction port is provided on the substrate loading side of the plasma space, from the curved electrode toward the roll electrode side, and
It is preferable that the gas is introduced along the transport direction of the base material.

The material of the gas introduction port is not particularly limited, but when it is made of a conductive material such as metal, in order to prevent discharge between the opposite electrode and the gas introduction port, the opposite electrode It is preferable to dispose an insulator between the gas inlet and the gas inlet.

The structure of the gas inlet is not particularly limited, but may be, for example, a jet nozzle system using a pressure pump. Further, a swash plate facing the gas introduction direction is provided, the gas supply passage is gradually narrowed to provide a narrowed portion near the gas introduction port, and after passing through the narrowed portion, the mixed gas is diffused and at the same time, in the substrate conveying direction. After changing the mixed gas flow in a substantially parallel manner, a method may be used in which a slit-like or a plurality of small holes are blown toward the plasma space from a blow-out port arranged in a line.

Further, it is preferable that the side surface of the plasma space formed between the roll electrode and the curved electrode (the side surface with respect to the rotating direction of the roll electrode) is sealed because the mixed gas is efficiently consumed.

11. Discharge plasma processing device (film forming device)
A preferred embodiment of the discharge plasma processing apparatus used in the present invention is shown in FIG. FIG. 2 is a diagram schematically showing the configuration of a film forming apparatus for carrying out the continuous film forming method using atmospheric pressure plasma according to the present invention.

The film forming apparatus shown in FIG. 2 mainly comprises high-voltage pulse power supply units 110 and 111 and a discharge plasma processing apparatus 1.
20, 121, unwinding roll 180, and take-up roll 18
It is composed of 1 etc.

The discharge plasma processing devices 120 and 121 are
Roll electrodes 130 and 131 and curved electrode 14 respectively
Counter electrode consisting of 0 and 141, and processing gas supply unit 15
0, 151 and sealing mechanisms 152, 153 and 154,
155 and processing gas discharge parts 170 and 171. Processing gas supply units 190 and 191 are connected to the processing gas supply units 150 and 151, respectively.
Further, processing gas exhaust pumps 1 and 2 are connected to the processing gas discharge portions 170 and 171, respectively. The roll electrodes 130, 131 and the curved electrodes 140, 1
The surface of 41 is covered with a solid dielectric. However, the solid dielectric of each roll electrode is omitted in FIG. 2 because it substantially coincides with the outer circumference of the roll electrode, and the solid dielectrics of each curved electrode are shown at 160 and 161.

Heating / cooling devices 182 and 183 are installed adjacent to the discharge plasma processing devices 120 and 121, respectively, so that the substrate film can be maintained at a temperature suitable for film formation. In addition, each discharge plasma processing device 12
0 and 121 are seal mechanisms 152, 153 and 154,
It is sealed at 155 and further sealed by a sealing mechanism (not shown), and is evacuated to a substantially vacuum state by the vacuum pumps 11 and 12.

In the discharge plasma processing apparatuses 120 and 121 having such a configuration, the vacuum pumps 10 and 20 reduce the pressure in the discharge plasma processing apparatuses 120 and 121 (in the processing container) to a substantially vacuum state, and then the rolls are rolled. Electrode 13
0, 131 and the curved electrodes 140, 141 (discharge space), the processing gas is supplied from the processing gas supply units 150, 151, and the processing gas discharge units 170, 17 are also discharged.
1 and the exhaust pumps P1 and P2 are exhausted to introduce the processing gas into each discharge space at a pressure near atmospheric pressure and at a constant flow rate, and the roll electrodes 130 and 131 and the curved electrodes 140 and 141 are connected to each other. In the meantime, the high voltage pulse power supply unit 110,
By applying a pulsed electric field from 111, it is possible to generate a discharge plasma according to the type of the processing gas between the opposed electrodes, and the generated plasma causes the substrate to travel along the roll electrodes 130 and 131. A thin film can be formed on the material film.

In the film forming apparatus shown in FIG. 2, the discharge plasma processing apparatuses 120 and 121 are provided with individual high-voltage pulse power supply units 110 and 111, respectively. However, discharge plasma is generated in the continuous film forming method of the present invention. A high voltage pulse power supply unit may be used in common as long as the conditions that occur can be satisfied.

Although FIG. 2 shows an example in which only the discharge plasma processing apparatus 120, 121 is depressurized and replaced with the processing gas, the unwinding roll 180, the take-up roll 181,
All of the heating / cooling devices 182 and 183 may be decompressed and replaced with the processing gas.

Here, the discharge plasma processing apparatus 12 described above is used.
At 0 and 121, the processing gas supply units 150 and 151
The processing gas introduced into the discharge space of each counter electrode from
It is required that a laminar flow is formed on the base film and that the flow velocity is substantially uniform in the width direction (process width) of the base film. FIG. 4 shows an example of the processing gas supply unit that satisfies such conditions. 4A is a sectional view of the processing gas supply unit, and FIG. 4B is a sectional view taken along the line AA of FIG. 4A.

In the processing gas supply unit shown in FIG. 4, a gas inlet 156 to which a gas supply pipe G is connected is provided at one longitudinal end of a rectangular processing gas supply unit 150, and two processing chambers are provided. 157 and 158 are provided in the first chamber 157.
Further, by providing the swash plate 114 on the diagonal line of the first chamber 157 so as to face the gas introduction direction,
The gas inlet 1 forms a section that becomes narrower as it goes away from 6
The process gas introduced from 56 is made turbulent to make the density in the compartments substantially uniform to make the flow velocity substantially uniform, and at the same time, the direction of the process gas is deflected. Room 1
The gas is rectified from a large number of small hole groups 115 provided in the vicinity of the edge of 57 and blown out into the second chamber 158. In the second chamber 158, a uniform gap 123 is formed at one end.
The partition plate 124 having a space is arranged, and the slit 125 having a uniform width is formed in the vicinity of the edge portion.
The gas discharged from the group of small holes 115 of 57 goes around the partition plate 124, and becomes a laminar flow from the slit 125 and is blown out to the discharge space.

12. In the discharge plasma treatment apparatus for carrying out the method for producing an antireflection film in the present invention, the base material is brought into close contact with the roll electrode, and the base material is introduced into the plasma space by rotating the roll electrode in accordance with the transport speed of the base material, In the mixed gas atmosphere introduced from the gas inlet,
By applying a voltage (electric field) between the roll electrode and the curved electrode to generate discharge plasma, an inorganic thin film or the like can be continuously formed on the base material.

The electric field applied between the roll electrode and the curved electrode is not particularly limited as long as it can uniformly generate discharge plasma, but a pulsed electric field is preferable. . That is, under a pressure near atmospheric pressure, except for gas components that take a long time to reach the arc discharge state from the plasma discharge state, the plasma discharge state is not stably maintained and instantaneously shifts to the arc discharge state. By applying the generated electric field, the discharge between the electrodes can be stopped before the transition from the glow discharge to the arc discharge, and by forming such a periodic pulsed electric field between the opposing electrodes, the microscopic Pulsed glow discharge is repeatedly generated, and as a result, discharge plasma can be generated for a long time in a stable glow discharge state.

The pulse voltage waveform may be an impulse type, a square wave type, or a modulation type waveform, and even if the applied voltage is positive or negative, the voltage is applied to either the positive or negative polarity side. It may be a single-sided waveform. The voltage rise time of the pulsed electric field is preferably 100 μs or less. Applying such a high-speed pulse leads to the generation of high-density plasma, and is important for achieving high-speed continuous processing. Here, the rise time refers to the time during which the voltage change is continuously positive.

The shorter the voltage rise time of the pulsed electric field, the more efficiently the gas is ionized during plasma generation. When the pulse rise time exceeds 100 μs, the discharge state easily shifts to an arc and becomes unstable. The high-density plasma state due to the electric field cannot be expected. In addition, it is preferable that the rise time is short, but there is a limitation in an apparatus that has an electric field strength that is large enough to generate plasma at normal pressure and that generates an electric field with a fast rise time. It is difficult to achieve a pulsed electric field with a rise time of less than. More preferably, the rise time is 50 ns to 5 μs.

Further, it is preferable that the voltage fall time of the pulsed electric field is also steep, and it is the same as the rise time.
It is preferable that the time scale is 00 μs or less.
The frequency of the pulsed electric field is preferably 0.5 kHz to 100 kHz. If the frequency is less than 0.5 kHz, the plasma density is low, so it takes too long to process, and 100 kH
If it exceeds z, arc discharge is likely to occur. More preferably, it is 1 kHz or more, and by applying such a high frequency pulsed electric field, the processing speed can be greatly improved.

The pulse duration in the pulse electric field is preferably 1 to 1000 μs. 1μ
If it is less than s, the discharge becomes unstable and 1000μ
If it exceeds s, it becomes easy to shift to an arc discharge state. More preferably, it is 3 μs to 200 μs. Here, the pulse duration refers to the time during which a pulse continues in a pulse electric field that is repeatedly turned on and off. Also,
Direct current may be superimposed on the application of the pulse voltage.

In the atmospheric plasma CVD method, an electric field is applied under a pressure near atmospheric pressure in a gas atmosphere containing a metal compound so that a discharge current density is 0.2 to 300 mA / cm ² between opposing electrodes. Thereby, discharge plasma is generated and an antireflection film is formed. The discharge current density is a value obtained by dividing the current flowing between the opposing electrodes by the discharge by the discharge area in the direction orthogonal to the current flowing direction in the discharge space.
When a parallel plate type electrode is used as the electrode, it corresponds to the current value divided by the facing area.

When the electric field applied between the electrodes is a pulsed electric field, it means the positive and negative maximum values of the pulse current, that is, the peak-peak value divided by the above area. When the antireflection layer is formed under the above conditions, a film quality equivalent to sputtering can be obtained, and continuous film formation equivalent to the coating method can be performed, which is advantageous in terms of productivity and cost.

13. Antireflection film The feature of the present invention is to supply a raw material gas containing a low refractive index material on the high refractive index layer in a state where a part of the reactivity is left, and perform discharge plasma treatment to obtain a high refractive index and a low refractive index. It is to form a layer having a refractive index in the middle of the index. This makes it possible to reduce the difference in refractive index between the high refractive index layer and the low refractive index layer, and obtain an antireflection film characteristic close to that of the coating type.

In order to leave the reactivity in the high refractive index layer, it is sufficient to weaken the discharge plasma treatment when forming the high refractive index layer.
Specifically, the discharge power may be weakened or the traveling speed of the base film may be increased. When using titanium tetraisopropoxide as the high refractive index material in our device,
The traveling speed of the base material is preferably 0.8 m / min or more, and 1.0
More preferably m / min or more. The discharge power is 0.1
-0.6 kW is desirable, and 0.2-0.4 kW is more desirable. The discharge plasma treatment of the low refractive index material which is continuously performed may be performed under normal conditions.

The fact that a layer having an intermediate refractive index between a high refractive index and a low refractive index was formed means that the high refractive index layer alone and the two-layer laminated film were measured for spectral reflectance and analyzed by thin film analysis. It can be judged from the difference in the refractive index of the refractive index layer. When titanium tetraisopropoxide is used as the high refractive index material in the device of the present inventors, the refractive index at a wavelength of 550 nm is 1.9 or more when it is used alone, but when the reactivity is left in the high refractive index layer. It will be 1.7 or less.

The antireflection film of the present invention has a wavelength of 550.
The high refractive index layer having a refractive index of 1.65 to 1.75 has an optical film thickness (refractive index x film thickness) of 140 to 200 nm, and a low refractive index such that the minimum reflection wavelength is 550 to 600 nm. It is characterized by laminating materials. When the optical film thickness of the high refractive index layer is less than 140 nm, the reflectance on the short wavelength side is higher than the minimum reflection wavelength, and the color of the reflected light is dark. On the other hand, if it is larger than 200 nm, the reflectance on the shorter wavelength side than the minimum reflection wavelength becomes too low, and the color becomes reddish.

If the minimum reflection wavelength is smaller than 550 nm, the color is reddish, and if it is larger than 600 nm, the reflectance in the vicinity of 550 nm, where the human eye has the highest luminosity, becomes high, and the film does not function as an antireflection film. The antireflection film of the present invention may be imparted with a hard coat property, an antistatic property, an antifouling property, an adhesive property, and a coloring property depending on the use.

[0065]

EXAMPLES The antireflection film of the present invention and the method for producing the same are described in detail below with reference to Examples and Comparative Examples, but the present invention is in no way limited by these Examples and Comparative Examples. is not.

[Explanation of Film Forming Apparatus Used] First, in the film forming apparatus shown in FIG.
The roll electrodes 130 and 131 arranged in 0 and 121 are made of stainless steel and have a width of 810 mm and a diameter of 400 mm, and have a thickness of 1.5 m as a solid dielectric on the electrode facing surface.
m aluminum oxide coated by a thermal spraying method was used. The curved electrodes 140 and 141 have a projected area of 810 mm in width and 100 m in length made of stainless steel.
m, the radius of curvature was 202 mm, and the surface facing the electrode was coated with aluminum oxide having a thickness of 1.5 mm by a thermal spraying method as a solid dielectric.

As the processing gas supply units 150 and 151 and the processing gas discharge units 170 and 171, those having the slits 125 for blowing gas shown in FIG. 4 were used. High-voltage pulse power supplies 110 and 111 manufactured by Heiden Institute (semiconductor element: IXYS, model number IXBH4
0N160-627G), using the roll electrode 1
5, between the curved electrodes 140, 141 and 30, 131.
A pulse electric field having a rise time of 5 μs and a pulse width of 70 μs was applied with the pulse voltage waveform shown in FIG.

Then, the substrate film was taken out by the unwinding roll 180 and the winding roll 181 at 9.8 N / m.
^{It is} run while applying a tensile stress of ² and introduced into each of the discharge plasma processing devices 120 and 121, and the vacuum pump P1
After setting the inside of the discharge plasma processing apparatus 120, 121 to about 133 Pa at 1, P12, returning to atmospheric pressure with a carrier gas,
Under the processing conditions of each example, a processing gas excited by discharge plasma was brought into contact with the surface of the base film to form a thin film on the base film.

(Example 1) In FIG. 2, a width of 800 m
m, PET with a thickness of 188 μm (manufactured by Teijin Ltd., OFW18
8) A base film having a 5 μm thick acrylic hard coat applied on the film was brought into close contact with the roll electrode 130, and the base film was run at a running speed of 1.0 m / min. Tetraisopropoxy titanium 1.5 g / min as a raw material and argon 60 SLM as a carrier gas were introduced into the discharge plasma processing apparatus 120, and the repetition frequency was 20 kHz.
A TiO ₂ film was formed on the PET substrate film by applying a pulse voltage of z and power of 0.2 kW to cause plasma discharge.
Subsequently, tetramethoxysilane 0.8 g / min as a raw material, nitrogen 25 SLM and oxygen 5 SLM as a carrier gas were introduced into the discharge plasma processing apparatus 121, and a pulse voltage with a repetition frequency of 6 kHz and power of 1.7 kW was applied to perform plasma discharge. Then, SiO ₂ was deposited on TiO ₂ to obtain an antireflection film.

Comparative Example 1 The same substrate film as in Example 1 was used, the running speed was 0.25 m / min, and the discharge plasma treatment apparatus 120 was charged with 0.2 g / min of tetraisopropoxy titanate as a raw material and carrier gas. As argon 6
0 SLM was introduced, a pulse voltage with a repetition frequency of 20 kHz and a power of 0.8 kW was applied to cause plasma discharge, and TiO ₂ was deposited on the PET substrate film. continue,
In the discharge plasma processing apparatus 121, tetraethoxysilane 0.2 g / min as a raw material and nitrogen 25 as a carrier gas.
Introducing SLM and oxygen 5SLM, repetition frequency 6kHz
A pulse voltage of z and electric power of 1.7 kW was applied to cause plasma discharge to form SiO ₂ on TiO ₂ to obtain an antireflection film.

(Comparative Example 2) As a coating type PET-based antireflection film, Rialck 72 manufactured by NOF CORPORATION
01 was prepared.

(Evaluation Method) [Optical Properties] The antireflection film was cut into a 5 cm square,
The back surface was roughened with # 400 sandpaper and then painted with a black marker to a size of about 2 cm in diameter. A spectrophotometer (manufactured by Hitachi Ltd., model “U-
3000 "). The result is shown in FIG. From this spectrum, the minimum reflection wavelength, the minimum reflectance, and the visibility-corrected average reflectance (Y) were read. This reflectance spectrum is analyzed by optical characteristic calculation software (JA Woollam,
V. A. S. E. for Windows (R) and the film thickness and wavelength of the high refractive index layer and the low refractive index layer 5
The refractive index at 50 nm was calculated.

[Physical Properties] (Pencil Hardness) The pencil hardness was evaluated according to JIS-K6894. (Scratch resistance) Steel wool # 0000 200 g / c
It was rubbed 20 times with a load of m ² and evaluated for scratches. The above results are shown in Table 1.

[0074]

[Table 1]

[0075]

In the method for producing an antireflection film of the present invention, a low refractive index material penetrates into the high refractive index layer to lower the refractive index, so that a medium refractive index layer can be obtained. Further, since the high refractive index layer and the low refractive index layer are formed without having an interface, the interface adhesion between the high refractive index layer and the low refractive index layer is improved. The method for producing an antireflection film using atmospheric pressure plasma of the present invention is configured as described above, since the difference in refractive index between the high refractive index layer and the low refractive index layer is small, the average reflectance is small, and It is possible to obtain an antireflection film having a light color and excellent film hardness at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a discharge plasma processing apparatus for carrying out a continuous film forming method using atmospheric pressure plasma.

FIG. 2 is an explanatory view showing an example of a discharge plasma processing apparatus for carrying out a continuous film forming method using atmospheric pressure plasma of the present invention.

FIG. 3 is a diagram showing the optical performance of antireflection films of Examples and Comparative Examples of the present invention.

FIG. 4 is a diagram showing a processing gas supply unit.

[Explanation of symbols]

1 Process gas exhaust pump 2 Process gas exhaust pump 11 vacuum pump 12 Vacuum pump 10 roll electrode 20 curved electrode 30 curved discharge space 40 Flow control valve 50 vacuum pump 110 High voltage pulse power supply 111 High voltage pulse power supply 112 Base film 113 Base film 114 Swash plate 115 small holes 120 Discharge plasma processing device 121 Discharge plasma processing device 123 gap 124 Partition board 125 slits 130 roll electrode 131 roll electrode 140 Counter electrode consisting of curved electrodes 141 Counter electrode consisting of curved surface electrode 150 Processing gas supply unit 151 Processing gas supply unit 152 seal mechanism 153 Sealing mechanism 154 sealing mechanism 155 sealing mechanism 156 gas inlet 157 Room 1 158 second room 160 solid dielectric 161 Solid Dielectric 170 Processing gas outlet 171 Processing gas discharge part 180 Unrolling roll 181 take-up roll 182 Heating / cooling device 183 Heating / cooling device 190 Processing gas supply system 191 Processing gas supply system

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2K009 AA05 AA10 BB24 CC03 CC42                       CC45 DD04 DD09                 4F100 AA20C AA21B AA27B AA28B                       AA33B AJ05A AJ06A AK01A                       AK04A AK07A AK08A AK12A                       AK15A AK16A AK21A AK25A                       AK42A AK45A AK46A AK49A                       AK54A AK55A AK56A AR00B                       AR00C BA03 BA04 BA10A                       BA10C EG002 EJ612 JK06                       JN06 JN18B JN18C YY00B                       YY00C                 4K030 AA11 AA14 BA01 BA10 BA11                       BA13 BA17 BA22 BA42 BA45                       BA46 BA47 CA07 CA12 FA03                       LA18

Claims (7)

[Claims] 1. At least two kinds of materials are formed on a base film by using discharge plasma generated by applying an electric field between opposite electrodes in a source gas atmosphere containing a metal compound under a pressure near atmospheric pressure. In the method of manufacturing an antireflection film for forming a metal compound film with a different refractive index, a raw material gas containing a high refractive index material is supplied, and discharge plasma treatment is performed to achieve high refractive index The first step of forming the refractive index layer on the base material film, and then a raw material gas containing a low refractive index material is supplied onto the high refractive index layer, and discharge plasma treatment is performed to obtain a high refractive index and a low refractive index. A method for producing an antireflection film, comprising a second step of forming a layer having a refractive index in the middle of the refractive index. 2. In the first step, either the discharge power is weakened or the traveling speed of the base film is increased in order to form a high refractive index layer in which a part of the reactivity remains. 2. The method for producing an antireflection film according to claim 1, wherein the discharge plasma treatment is performed under the conditions described above. 3. The high refractive index layer comprises ZrO ₂ , TiO ₂ ,
SnO ₂ , In ₂ O ₃ , ITO, Ta ₂ O ₅ , ZnO, Hf
The method for producing an antireflection film according to claim 1, which comprises at least one metal oxide having a large refractive index selected from O ₂ , CeO ₂ , Nb ₂ O ₅ , and Y ₂ O ₃ . 4. The substrate film is polyethylene terephthalate, polyethylene naphthalate, polymethylmethacrylate, polycarbonate, regenerated cellulose,
Consists of a transparent resin selected from diacetyl cellulose, triacetyl cellulose, norbornene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyether sulfone, polyether ketone, polyethylene, polypropylene, polyimide, polyamide or poly 4-methylpentene 1. The method for producing an antireflection film according to claim 1, wherein the antireflection film is produced. 5. The raw material gas containing the low refractive index material is tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, diethoxydimethylsilane, tetramethylsilane, tetraethylsilane. , Tetraethoxysilane, dimethoxydimethylsilane, dimethylsilane,
The method for producing an antireflection film according to claim 1, which is one or more kinds of compounds selected from tetramethylsilane, monosilane, silane, silane dichloride, or silane trichloride. 6. The continuous production method of an antireflection film according to claim 1, wherein the first step and the second step are continuously performed by separate discharge plasma processing apparatuses. 7. An antireflection film comprising a high-refractive index layer and a low-refractive index layer sequentially laminated on a base film without having an interface, wherein the high-refractive index layer has a refractive index at a wavelength of 550 nm. 1.6
5 to 1.75, the optical film thickness is 140 to 200 nm,
On the other hand, the low refractive index layer has a minimum reflection wavelength of 550 to 600 n.
m is an antireflection film.