JP2005114876A - Antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film making a high gas barrier function compatible with high antireflection performance. <P>SOLUTION: The antireflection film is a laminated body obtained by laminating transparent base substance film, a transparent inorganic thin film containing at least nitrogen and silicon, and a silicone resin layer or a fluorocarbon resin layer in this order. The transparent inorganic thin film has high transparency, high gas barrier properties and a high refractive index, and is combined with the silicone resin layer or the fluorocarbon resin layer having a low refractive index, whereby the antireflection film having the high gas barrier properties and the high antireflection properties concurrently is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

 The present invention relates to an antireflection film. More specifically, the present invention relates to an antireflection film having a gas barrier function. The present invention also relates to a display device using the above antireflection film.

  In recent display devices, for example, in televisions, large screens and thinnings using PDPs (plasma displays) and liquid crystal displays are progressing in place of conventional cathode ray tubes. Since these displays have high image quality, the reflection of light and objects on the screen has a great influence on the appearance of the image, and it is essential to provide antireflection performance.

  In addition, display methods such as liquid crystal and organic EL (electroluminescence) are used. For example, display materials for mobile devices such as mobile phones, PDAs, and electronic papers are used outdoors. It has a great influence on the image, and it is essential to provide antireflection performance.

As one of these antireflection methods, conventionally, a method of attaching only an antireflection function or a film having an antireflection function provided with a surface protective layer to a display portion of a display device has been used. Specifically, there are disclosures in JP-A-09-193327 (Patent Document 1), JP-A-2002-341107 (Patent Document 2), and the like. On the other hand, there are attempts to use a plastic plate for the transparent substrate on the display side of a liquid crystal display or to use a plastic plate for the display side of a top emission type organic EL display. While plastic plates generally tend to be inferior in gas barrier properties compared to glass, the above-described display tends to be affected by oxygen and water vapor in internal elements. For this reason, it is considered necessary to provide not only an antireflection function but also gas barrier performance of oxygen and water vapor to the screen portion. In particular, in display materials for mobile devices, where the market has been growing rapidly in recent years, instead of conventional glass substrates, studies are underway to use plastic substrates that can be made light and thin and that do not break. In order to increase the lifetime and reliability of the film and to obtain a beautiful image, the appearance of an antireflection film having a particularly high oxygen and water vapor gas barrier performance is expected.
JP 09-193327 A, JP 2002-341107 A

  Accordingly, an object of the present invention is to provide a film having not only antireflection performance but also a gas barrier function.

As a result of investigations by the present inventors to solve the above problems, a film having a multilayer structure comprising a transparent substrate film, a transparent inorganic thin film containing at least nitrogen and silicon, and a transparent resin layer has a gas barrier function and reflection. The present invention was completed by finding that the prevention function can be compatible at a high level. That is, the present invention
(1) a transparent substrate film (A);
A transparent inorganic thin film layer (B) containing at least nitrogen and silicon;
It consists of a transparent resin layer (C),
The refractive index of each layer has a relationship of transparent resin layer (C) <transparent substrate film (A) <transparent inorganic thin film layer (B),
(A) / (B) / (C) is an antireflection film having a laminated structure of the order,
(2) a transparent substrate film (A),
A transparent inorganic thin film layer (B) containing at least nitrogen and silicon;
It consists of a transparent resin layer (C),
The refractive index of each layer has a relationship of transparent resin layer (C) <transparent substrate film (A) <transparent inorganic thin film layer (B),
(A) / (C) / (B) / (C) is an antireflection film having a laminated structure of the order,
(3) The transparent resin layer (C) is an antireflection film that is a silicone resin layer (C1),
(4) The transparent resin layer (C) is an antireflection film that is a fluororesin layer (C2),
(5) The transparent inorganic thin film layer (B) is an antireflection film which is a silicon nitride thin film layer (B1),
(6) The silicon nitride thin film layer (B1) is an antireflection film that is a silicon nitride thin film layer (B2) formed by a catalytic CVD method,
(7) A display device in which the antireflection film is bonded to the surface of the display unit,
(8) A display device using the antireflection film as a display unit substrate.

  The film having a structure in which a film containing at least nitrogen and silicon is formed on the surface of the plastic film or the undercoat layer of the present invention and further coated with a silicone resin or a fluorine resin on the surface has a high gas barrier function and antireflection performance. Have For this reason, since it can be suitably used for display applications where the market growth has been remarkable in recent years, particularly for liquid crystal displays and organic EL displays, the industrial significance of the present invention is great.

  The antireflection film of the present invention has a transparent substrate film, a transparent inorganic thin film layer containing at least nitrogen and silicon, and a transparent resin layer.

  In the present invention, “transparent” means that the visible light transmittance is 50% or more, preferably 70% or more, more preferably 80% or more. The upper limit of the visible light transmittance is 100%, but in reality, it is often 95% or less because of surface reflection and absorption by the material.

  First, each layer will be described.

(Transparent substrate film (A))
As the transparent substrate film (A) according to the present invention, a plastic film is preferably used. The plastic film is not particularly limited as long as it is a transparent film. Specifically, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polysulfone, polyethersulfone, polyester, polymethyl methacrylate, polycarbonate, polyarylate, polyacetate, polyamide, poly-4-methylpentene-1, cellulose, poly Examples thereof include films made of a resin having transparency such as vinyl chloride, polyacrylonitrile resin, phenoxy resin, polyphenylene oxide resin and the like.

  The refractive index of the transparent substrate film (A) of the present invention varies depending on the refractive index of the inorganic thin film layer (B) and the transparent resin layer (C) described later, but is generally 1.4 to 1.7, preferably 1.5-1.7.

  The thickness of the transparent substrate film (A) of the present invention is not particularly limited, but is 10 μm to 250 μm, preferably 50 μm to 200 μm in view of the film self-supporting property, handling property, impact resistance and the like.

(Transparent inorganic thin film layer (B))
The transparent inorganic thin film layer (B) in the present invention contains at least nitrogen and silicon and is a transparent layer in the visible light region. Further, a layer having a high gas barrier performance is preferable. Specifically, a silicon nitride thin film or a silicon oxynitride thin film is preferable, and a silicon nitride thin film (B1) is particularly preferable. If the inorganic thin film contains hydrogen, carbon, or the like as long as it is in a range satisfying the transparency in the visible light region and the desired gas barrier performance, the present invention is not hindered at all.

  The preferable refractive index of the transparent inorganic thin film layer (B) in the present invention is 1.5 to 2.1, more preferably 1.8 to 2.1. The refractive index can be controlled by the type and composition of the compound forming the transparent inorganic thin film layer (B), film forming conditions, and the like. Specifically, it is possible to control within a range of about 1.8 to 2.1 for a silicon nitride thin film and about 1.5 to 2.1 for a silicon oxynitride thin film.

  The film thickness of the transparent inorganic thin film layer (B) in the present invention is preferably 5 to 500 nm, more preferably 10 to 200 nm, from the viewpoint of gas barrier performance and bending resistance to gas barrier performance, and is set according to various applications. It is appropriately selected according to the antireflection performance and manufacturing cost.

  The transparent inorganic thin film layer (B) in the present invention does not have to be a single layer, and may be composed of two or more layers different in the type of compound, refractive index, film thickness and the like. In some cases, it is possible to obtain a preferable result that the antireflection function can be improved by using a multi-layered structure.

  In the present invention, the transparent inorganic thin film layer (B) typified by a silicon nitride thin film or a silicon oxynitride thin film can be formed by a known film forming method. Specifically, a method of forming a film by sputtering or plasma CVD (chemical vapor deposition) can be exemplified. In particular, for silicon nitride thin film formation, the refractive index can be controlled between 1.8 and 2.1 by using a catalytic CVD method in which gas molecules are decomposed and activated by a heating element to form a film on a substrate. It is desirable because a film having excellent gas barrier properties and transparent and low film stress can be formed.

(Transparent resin layer (C))
In the present invention, the transparent resin layer (C) is not particularly limited as long as it is transparent and satisfies the refractive index condition described later. Preferably, the silicone resin layer (C1) or the fluororesin layer (C2) is used. ). Silicone resins are resins mainly composed of silicon, oxygen, and hydrogen, and products having various compositions and molecular weights are commercially available. For the silicone resin layer (C1) of the present invention, these known resins can be used without particular limitation as long as they satisfy the requirements of the refractive index described later. As the fluororesin layer (C2) in the present invention, a known resin can be used without limitation as long as it satisfies the requirements of transparency and a refractive index described later. Specific examples include fluorinated ethylene resin, fluorinated ethylene chloride resin, fluorinated ethylene, fluorinated propylene resin, and vinylidene fluoride resin.

  Since the refractive index of the transparent resin layer (C) in the present invention is appropriately selected depending on the refractive index of the transparent substrate film (A) and the transparent inorganic thin film layer (B) described later, Is 1.3 to 1.6, preferably 1.3 to 1.5. In addition, the film thickness of the transparent resin layer (C) in the present invention, when used as an undercoat of a transparent inorganic thin film layer, is from a viewpoint according to requirements such as manufacturing cost and surface smoothness required by various applications. Since it is determined as appropriate, there is no particular limitation, but it is generally 0.1 to 20 μm, more preferably 0.1 to 10 μm. When used as a coating on a transparent inorganic thin film layer, reflection required for various applications is required. Since it is appropriately determined from the viewpoint of performance, manufacturing cost, surface smoothness and other requirements, there is no particular limitation, but generally 0.05 to 10 μm, more preferably 0.1 to 2 μm.

  The transparent resin layer (C) in the present invention can be formed by a known method such as roll coating, gravure coating, knife coating, dip coating or spray coating.

(Antireflection film)
The antireflection film of the present invention comprises the transparent substrate film (A), the transparent inorganic thin film layer (B), and the transparent resin layer (C), and is laminated in the order of (A) / (B) / (C). It has a structure. In addition, the reflective film of the present invention does not need to have the above three-type three-layer structure within the range of the object of the present invention, and there is a combination in the order of (A) / (B) / (C). If so, a multi-layered structure may be used. However, the outermost layer of at least one main surface is preferably a transparent resin layer (C). The increase in the number of layers may increase the manufacturing cost and make it difficult to control the antireflection performance, so the upper limit of the number of layers in each layer is 10 layers or less, preferably 5 layers or less.

  A particularly preferable configuration of the antireflection film of the present invention is a configuration in which two transparent resin layers (C) to be (A) / (C) / (B) / (C) are formed, and particularly excellent in gas barrier properties. Show performance.

In the present invention, the refractive index of the transparent substrate film (A), the transparent inorganic thin film layer (B), and the transparent resin layer (C) is:
Transparent resin layer (C) <Transparent substrate film (A) <Transparent inorganic thin film layer (B)
Have the relationship. The above-described ranges of the refractive index of each layer include a partially overlapping region, but it is only necessary that the refractive index of each layer that actually forms the antireflection film of the present invention satisfies the above relationship.

  Further, the antireflection film of the present invention can also form other layers as long as the object of the present invention is not impaired. Specific examples include an undercoat layer for enhancing adhesion, surface smoothness, and gas barrier properties between the transparent substrate film (A) and the inorganic transparent thin film layer (B). Examples of the material for forming the undercoat layer include ethylene / vinyl alcohol resin, vinyl-modified resin, acrylic resin, polyester resin, isocyanate resin, urethane resin, epoxy resin, modified styrene resin, and modified silicone resin. I can do it. These may be used alone or in combination of two or more.

  In the present invention, the transparent resin layer disposed between the plastic film substrate and the inorganic thin film layer can be formed by roll coating, gravure coating, knife coating, dip coating, spray coating, or the like.

  The antireflection film according to the present invention, for example, when a plastic plate is used for the transparent substrate on the display side of a liquid crystal display, or when a plastic plate is used for the display side of a top emission type organic EL display, is used for light and object screens. Reflection can be suppressed, and deterioration of the internal elements can be reduced or prevented.

  Also, by using it as an element substrate that also serves as a liquid crystal or organic EL display part, reflection of light and objects on the screen can be prevented, and element deterioration due to the entry of oxygen, water vapor, etc. into the display element part Can be protected against.

In the following, embodiments of the present invention will be described.
Example 1
A 125 μm thick PET film having a refractive index of 1.65 in the visible region is used as a substrate, and silane gas, ammonia gas, and hydrogen gas are placed on the film by a catalytic CVD method in a vacuum container in which the film is provided. By introducing and heating the tungsten wire as a heating element to about 1700 ° C and keeping the substrate temperature at 70 ° C, a silicon nitride thin film having a refractive index of 1.87 in the visible region has a film thickness of 50 nm. The formation was performed as follows.

  Further, a silicone resin having a refractive index of 1.42 in the visible region was coated on the silicon nitride film so as to have a thickness of 100 nm by spin coating. As a specific spin coating method, a solid silicone resin (ladder type silicone oligomer product name: Glass Resin GR100, manufactured by Showa Denko KK) was used in a solution of 30 wt% in isopropyl alcohol. The crosslinking reaction and drying conditions were performed in a clean oven at 120 ° C. for 12 hours.

FIG. 1 shows the configuration of the second embodiment. The reflectivity at each wavelength of the film measured with UV-3100PC manufactured by Shimadzu Corporation was a value shown in Table 1. In addition, when the moisture permeability measurement was performed at a temperature of 40 ° C. and a relative humidity of 100% using PERMATRAN-W600 manufactured by Modern Control, the value was 1.2 g / m ² / day as shown in Table 1.

Example 2
A 125 μm thick PET film having a refractive index of 1.65 in the visible region was used as the substrate, and a silicone resin having a refractive index of 1.42 in the visible region was coated on the film by spin coating so as to have a thickness of 2 μm.

  Subsequently, silane gas, ammonia gas, and hydrogen gas are introduced into the vacuum container in which the film is disposed on the silicone resin layer of the film by a catalytic CVD method, and the tungsten wire as a heating element is heated to about 1700 ° C. By heating and maintaining the substrate temperature at 70 ° C., a silicon nitride thin film having a refractive index of 1.87 in the visible region was formed to a thickness of 50 nm.

  Further, a silicone resin having a refractive index of 1.42 in the visible region was coated on the silicon nitride film so as to have a thickness of 100 nm by spin coating.

FIG. 2 shows the configuration of the second embodiment. The reflectivity at each wavelength of the film measured with UV-3100PC manufactured by Shimadzu Corporation was a value shown in Table 1. In addition, when the moisture permeability measurement at a temperature of 40 ° C. and a relative humidity of 100% was performed with PERMATRAN-W600 manufactured by Modern Control, as shown in Table 1, the detection limit in this measurement was 0.02 g / m ^2. The value was less than / day.

Below, the comparative example of this invention is shown.
Comparative Example 1
The reflectivity at each wavelength of a 125 μm-thick PET film having a refractive index in the visible range measured by UV-3100PC manufactured by Shimadzu Corporation was a value shown in Table 1. In addition, when measuring moisture permeability at a temperature of 40 ° C. and a relative humidity of 100% using PERMATRAN-W600 manufactured by Modern Control Co., Ltd., the value was 5.3 g / m ² / day as shown in Table 1.

Comparative Example 2
A 125 μm thick PET film having a refractive index of 1.65 in the visible region is used as a substrate, and silane gas, ammonia gas, and hydrogen gas are placed on the film by a catalytic CVD method in a vacuum container in which the film is provided. By introducing and heating the tungsten wire as a heating element to about 1700 ° C and keeping the substrate temperature at 70 ° C, a silicon nitride thin film having a refractive index of 1.87 in the visible region has a film thickness of 50 nm. The formation was performed as follows.

FIG. 3 shows the configuration of this comparative example. The reflectivity at each wavelength of the film measured with UV-3100PC manufactured by Shimadzu Corporation was a value shown in Table 1. Further, when the moisture permeability was measured at a temperature of 40 ° C. and a relative humidity of 100% using PERMATRAN-W600 manufactured by Modern Control, the value was 1.4 g / m ² / day as shown in Table 1.

Comparative Example 3
A 125 μm thick PET film having a refractive index of 1.65 in the visible region was used as the substrate, and a silicone resin having a refractive index of 1.42 in the visible region was coated on the film by spin coating so as to have a thickness of 2 μm.

  Subsequently, silane gas, ammonia gas, and hydrogen gas are introduced into the vacuum container in which the film is disposed on the silicone resin layer of the film by a catalytic CVD method, and the tungsten wire as a heating element is heated to about 1700 ° C. By heating and maintaining the substrate temperature at 70 ° C., a silicon nitride thin film having a refractive index of 1.87 in the visible region was formed to a thickness of 50 nm.

FIG. 4 shows the configuration of this comparative example. The reflectivity at each wavelength of the film measured with UV-3100PC manufactured by Shimadzu Corporation was a value shown in Table 1. In addition, when the moisture permeability measurement at a temperature of 40 ° C. and a relative humidity of 100% was performed with PERMATRAN-W600 manufactured by Modern Control, as shown in Table 1, the detection limit in this measurement was 0.02 g / m ^2. / day or less

  In the above, the silicon nitride film can be produced by sputtering or plasma CVD other than the catalytic CVD method, and by selecting appropriate conditions, by adjusting the silicon / nitrogen composition ratio, etc., the desired gas barrier performance and A film having a refractive index can be obtained. For silicon oxynitride thin films, desired gas barrier performance and refractive index can be obtained by adjusting the silicon / oxygen / nitrogen composition ratio, etc., by sputtering or plasma CVD. Thereby, not only the characteristic shown by a present Example but the antireflection film which has desired gas barrier performance and low reflectance is realizable.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such embodiments, and various modifications can be made within the technical scope grasped from the description of the scope of claims. .

It is the schematic of the cross section of the antireflection film of Example 1 in this invention. It is the schematic of the cross section of the antireflection film of Example 2 in this invention. It is the schematic of the laminated body cross section of the comparative example 2 in this invention. It is the schematic of the laminated body cross section of the comparative example 3 in this invention.

Explanation of symbols

11 Film substrate (PET film)
12 Silicon nitride thin film 13 Silicone resin layer 21 Film substrate (PET film)
22 Silicone resin layer 23 Silicon nitride thin film 24 Silicone resin layer 31 Film substrate (PET film)
32 Silicon nitride thin film 41 Film substrate (PET film)
42 Silicone resin layer 43 Silicon nitride thin film

Claims (8)

A transparent substrate film (A);
A transparent inorganic thin film layer (B) containing at least nitrogen and silicon;
It consists of a transparent resin layer (C),
The refractive index of each layer has a relationship of transparent resin layer (C) <transparent substrate film (A) <transparent inorganic thin film layer (B),
An antireflection film having a laminated structure in the order of (A) / (B) / (C). A transparent substrate film (A);
A transparent inorganic thin film layer (B) containing at least nitrogen and silicon;
It consists of a transparent resin layer (C),
The refractive index of each layer has a relationship of transparent resin layer (C) <transparent substrate film (A) <transparent inorganic thin film layer (B),
An antireflection film having a laminated structure in the order of (A) / (C) / (B) / (C). The antireflection film according to claim 1 or 2, wherein the transparent resin layer (C) is a silicone resin layer (C1). The antireflection film according to claim 1 or 2, wherein the transparent resin layer (C) is a fluororesin layer (C2). The antireflection film according to claim 1, wherein the transparent inorganic thin film layer (B) is a silicon nitride thin film layer (B1). 6. The antireflection film according to claim 5, wherein the silicon nitride thin film layer (B1) is a silicon nitride thin film layer (B2) formed by a catalytic CVD method. The display device which bonded the antireflection film of Claims 1-6 on the display part surface. A display device using the antireflection film according to claim 1 as a display unit substrate.

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