JPH0631850A - High gas barrier transparent conductive film - Google Patents

Abstract

PURPOSE:To obtain transparency and excellent gas barrier properties by forming a thin film layer of a compsn. of a specified metal oxide and boron oxide at least on one face of a polymer film base material and a transparent conductive film wherein indium oxide is a main ingredient at least on one face thereof. CONSTITUTION:A thin film layer 2 with a film thickness of 10-1,000nm (MO+BO thin film) of a compsn. wherein at least one metal oxide (MO) selected from a group of silicon oxide, aluminum oxide and titanium oxide and boron oxide (BO) are incorporated by a molar ratio of BO:MO=0.05-0.2 is formed at least on one face of a polymer film base material 1. In addition, a transparent conductive film 3 wherein indium oxide is a main ingredient is formed by means of a vacuum deposition method etc., at least on one face of the film. As the polymer film for the base material, polyether sulfone and polyimide are pref. As the MO+BO thin film 2, it is pref. that a uniform continuous film with a great thickness of at least 10nm and at most 1,000nm is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive film having a polymer film as a base material, more specifically to a transparent conductive film having a high gas barrier property, and further preferably used for liquid crystal display. And a transparent conductive film having a high gas barrier property.

[0002]

2. Description of the Related Art Conventionally, glass has been used as a base material for transparent conductors for liquid crystal displays, but in recent years, it has been lightweight, easy to increase in area, unbreakable, and excellent in workability. Transparent conductive films, which have the property of being present, have been used for electrodes. However, it has been found that when a conductive film is used, a gas such as water vapor or oxygen that permeates the film causes performance deterioration of the liquid crystal element. In order to solve such a problem, it has become clear that it is necessary to provide a polymer film substrate with a gas barrier property.

In order to impart a barrier property to gas,
SiO, SiO on one or both sides of the polymer film
₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , N
Disclosed is a transparent conductive film in which a layer of oxide such as b ₂ O ₃ or aluminum nitride is provided, and a coating film containing indium oxide as a main component is formed on at least one surface of these polymer layers (for example, a special layer is used). JP-A-59-204545, JP-A-63
-205094). However, thin films of these oxides and nitrides have transparency and gas barrier properties to some extent, but since they are formed on a polymer film, they must be formed at a low temperature to obtain high barrier properties. I can't. Further, in order to obtain a high gas barrier property, when a metal such as aluminum used in the field of packaging materials is vapor-deposited, there is a drawback that the visible light transmittance is completely impaired.

[0004]

As described above, according to the prior art, it is difficult to simultaneously achieve transparency and complete gas barrier property in the transparent conductive film. An object of the present invention is to solve the above-mentioned drawbacks of the conventional methods and provide a transparent conductive film having transparency and excellent gas barrier properties.

[0005]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, as a transparent conductive film having high transmittance in the visible light region and extremely low gas permeability, a polymer On at least one side of the film substrate, silicon oxide, aluminum oxide, magnesium oxide,
At least one metal oxide (MO) selected from the group of titanium oxide and boron oxide (BO) has a molar ratio of BO /
The present invention was accomplished by finding a layer (MO + BO thin film) formed with MO = 0.05 to 0.2. That is, the present invention provides at least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide and titanium oxide (hereinafter referred to as M
O) and boron oxide (abbreviated as BO) in a molar ratio of B
O: 10 of the composition in which MO = 0.05-0.2
A transparent conductive film having a high gas barrier property, in which a thin film layer (MO + BO thin film) having a film thickness of 1000 nm is formed, and a transparent conductive film containing indium oxide as a main component is formed on at least one of the films. Is provided.

The transparent conductive film of the present invention may have various forms, and one example thereof is shown in FIGS. 5 to 8. Here, 1 is a polymer film substrate, 2 is M
O + BO thin film layer, 3 is a transparent conductive film. In the present invention, the polymer film serving as the base material is not particularly limited, but is 100 ° C. to 20 ° C. in the manufacturing process of the transparent conductive film.
Considering that the temperature becomes 0 ° C., it is desirable to have a certain degree of heat resistance, and examples thereof include polyester, polyether sulfone, polycarbonate, polyimide, polyolefin film, and the like. In particular, polyether sulfone,
Polyimide is preferred. The thickness of the base film is
Although not particularly limited, about 5 to 1000 μm is usually used. Of course, other film thicknesses can be used depending on the purpose.

The MO + BO thin film used in the present invention is 1
It is preferable to form a uniform continuous film with a film thickness of 0 nm or more and 1000 nm or less. As a result, excellent high gas barrier properties are exhibited without impairing transparency. If the thickness is less than 10 nm, the gas barrier property is not sufficient and the gas barrier property increases with an increase in the film thickness, but if the thickness is 100 nm or more, the property tends to be saturated, and if the thickness is 1000 nm or more, the adhesion strength of the film decreases. The thickness of the MO + BO thin film is preferably in the range of 10 to 1000 nm. Furthermore, it is preferably in the range of 20 to 500 nm.

The film thickness measurement in the present invention includes a stylus roughness meter, a repetitive reflection interferometer, a microbalance, and a method using a quartz oscillator. In the quartz oscillator method, the film thickness is measured during film formation. Therefore, it is suitable for obtaining a desired film thickness. Since the transparency decreases as the molar composition ratio BO / MO in the MO + BO thin film increases, the molar composition ratio BO / MO in the film of the present invention ranges from 0.05 to
0.2 is preferable. More preferably 0.05 to 0.1
Is.

In the present invention, the means for forming the MO + BO thin film is not particularly limited, but it can be formed by a known film forming method such as a physical vapor deposition method such as a magnetron sputtering method or an ion beam sputtering method. Further, a vacuum vapor deposition method, an electron beam vapor deposition method, or an ion plating method can be appropriately combined. The base material is a polymer material,
Since it is inferior in heat resistance to metals and ceramics, it is important to make it at a temperature as low as possible. For this purpose, a magnetron sputtering method or an ion beam sputtering method is effective, in which a desired metal oxide and BO are targeted and sputtering is performed by argon ions to form a film at room temperature without cooling the substrate. The composition of BO can be controlled by changing the ratio of the area occupied by the metal oxide and BO on the target surface in the sputtering method. Alternatively, in the case of manufacturing by a reactive sputtering method using oxygen as a reactive gas or a reactive ion plating method, it is possible to control the composition ratio of BO by depositing boron while controlling the flow rate of oxygen. Is. The composition is measured by X-ray photoelectron spectroscopy or X-ray
Line microanalysis can be used.

Before forming the MO + BO thin film, surface treatment such as corona discharge treatment, plasma treatment, glow discharge treatment, reverse sputtering treatment, surface roughening treatment, chemical treatment and the like and known under treatment are performed on the polymer film substrate as pretreatment. It is also preferable to appropriately apply the coating. Also, MO + BO
Although the film is chemically stable, it is desirable to form a protective layer on the MO + BO film if necessary when used under severe conditions for a long period of time. A transparent resin may be used for the protective layer, and examples thereof include polyester resin, acrylic resin, vinyl resin, and polycarbonate.

Incidentally, Japanese Unexamined Patent Publication (Kokai) No. 59-137927 discloses a technique relating to a silica coating film containing boron, but in the present invention, boron oxide, not boron, is uniformly dispersed in silicon oxide. , And that the film forming environment and the film forming method are low temperature and dry. Therefore, the structure and the physical properties of the produced film are different, and the present invention is essentially the same as that of JP-A-59-1379.
It is completely different from 27. Of course, the reference film cannot achieve the object of the present invention. The method for producing the transparent conductive layer containing indium oxide as a main component is not particularly limited, but it can be performed by a known film forming technique such as a vacuum vapor deposition method, an electron beam vapor deposition method, an ion plating method, and a sputtering method. For example, when the vacuum deposition method is used, a raw material mainly composed of indium oxide and an oxygen partial pressure of about 10 ⁻⁴ T
A transparent conductive layer can be obtained on the polymer film by evaporation by resistance heating in a vacuum controlled to orr.

[0012]

The high gas barrier transparent conductive film of the present invention, which is constructed as described above, has the following excellent effects. (1) Excellent gas barrier property. (2) Excellent transparency. (3) It can be suitably used as an electrode for liquid crystal display.

[0013]

【Example】

Example 1 PES of 50 μm was used as a base film, and a film having a molar composition ratio of BO / MO = 0.1 was formed with a film thickness of 1 by targeting SiO ₂ and B by a reactive magnetron sputtering method.
It was formed in a range of 0 nm to 1000 nm, and a conductive film layer containing indium oxide as a main component was formed thereon to a thickness of 20 nm. Table 1 shows the preparation conditions. The oxygen gas transmittance, the visible light transmittance, and the adhesion strength of the film were measured, and the results are shown in FIGS. 1 and 2. FIG. 1 shows the relationship between the gas permeability and the film thickness of the gas barrier layer. FIG. 2 shows the relationship between the transmittance of visible light and the film thickness of the gas barrier layer. Table 2 shows the results of the adhesion strength of the film measured by the Scotch tape test. Further, the transmittance of oxygen in the film thickness 50nm was 0.2cc / m ² / 24hr (1 atm).

Example 2 Using 100 μm PES as a substrate film, a film having a thickness of 100 nm was prepared by changing the molar composition ratio BO / MO by targeting SiO ₂ and B by reactive magnetron sputtering. The visible light transmittance and the helium gas transmittance were measured. The results are shown in FIGS. 3 and 4. FIG. 3 shows the relationship between the molar composition ratio BO / MO and the transmittance of visible light. FIG. 4 shows the molar composition ratio BO / M.
It shows the relationship between the transmittance of O and helium.

[0015]

[Table 1]

[0016]

[Table 2]

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between gas permeability and film thickness of a gas barrier layer.

FIG. 2 is a diagram showing the relationship between the transmittance of visible light and the film thickness of a gas barrier layer.

FIG. 3 is a diagram showing a relationship between a visible light transmittance and a molar composition ratio BO / MO.

FIG. 4 is a graph showing the relationship between helium transmittance and molar composition ratio BO / MO.

FIG. 5 is a schematic view showing an example of the layer structure of the conductive film of the present invention.

FIG. 6 is a schematic view showing an example of the layer structure of the conductive film of the present invention.

FIG. 7 is a schematic view showing an example of the layer structure of the conductive film of the present invention.

FIG. 8 is a schematic diagram showing an example of the layer structure of the conductive film of the present invention.

[Explanation of symbols]

 1 Polymer Film Base Layer 2 MO + BO Thin Film Layer 3 Transparent Conductive Layer

Claims (2)

[Claims] 1. At least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide and titanium oxide (hereinafter abbreviated as MO) and boron oxide (BO) on at least one surface of a polymer film substrate. (Abbreviation) is the molar ratio, BO / M
10-100 of the composition where O = 0.05-0.2
A transparent conductive film having a high gas barrier property, wherein a thin film layer having a film thickness of 0 nm is formed, and a transparent conductive film containing indium oxide as a main component is formed on at least one of the films. 2. The transparent conductive film having a high gas barrier property according to claim 1, wherein the polymer film is polyether sulfone.