JPS6013244B2 - Method for manufacturing a molded product having a transparent conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a molded article having a transparent conductive coating.

More specifically, using a molded product having a low light transmittance coating {1- on the surface of which is mainly composed of a low oxide of indium metal as a substrate, the coating '1} is coated by sputtering in oxygen or a gas containing oxygen. This relates to a method for manufacturing a molded article having a transparent conductive film having excellent transparency and excellent conductivity by oxidizing the film (11) while forming the metal or an oxide film (1) of the metal. The following method is cited as a method for manufacturing a molded article having a film containing indium oxide as a main component as a transparent film.

'a- A method of forming a transparent conductive film by vacuum evaporating indium metal or an oxide of indium metal onto the surface of a heated substrate in a vacuum chamber into which oxygen or a gas containing oxygen is introduced.

'b} A method of forming a transparent conductive film by an ionization plating method in which an evaporation source containing metallic indium or an oxide of indium metal as a main component and a molded product are placed facing each other, and a high-frequency discharge plasma region is formed in the space between the two. (For example, see Japanese Patent Application Laid-Open No. 51-111699).

(c) A method of forming a film mainly composed of a low oxide of indium metal by a vacuum evaporation method, and then oxidizing the film to form a transparent conductive film (for example, Hakama Kaisho 50-11
(See Publication No. 172).

Among these known methods, method 'a' can obtain a film with a relatively small resistance value, but since it is necessary to heat the substrate to 300° C. or higher, organic materials with low heat resistance cannot be used as the substrate. In addition, heating rods are required,
Further, it is unfavorable from an industrial standpoint, as it requires time for heating and cooling.

In this method, in order to form a film with better transparency, it is necessary to introduce a small amount of oxygen. It's giving no result. Method ``b-'' does not require heating the substrate, so it can be applied to materials with low heat resistance, and it is possible to obtain a transparent conductive film with excellent adhesion, but the equipment is complicated and expensive, and It also has the disadvantage of being difficult to adjust. ■,
[In both methods (b-), even if the evaporation source is metallic indium or an oxide whose main component is indium oxide, the evaporated gas is a low oxide. These low oxide particles are
It reacts with the introduced oxygen gas on the substrate or in the space before it reaches the substrate to form indium oxide and forms a film on the molded product, and the reaction energy is ta}. Or, as in the case of {b-, it is necessary to generate high-frequency plasma. In any case, it is not desirable to introduce oxygen gas into a vacuum chamber, and the rate of film formation is slow because the evaporated particles are scattered due to frequent collisions between the evaporated particles and the introduced gas. It has its drawbacks. On the other hand, method [c} forms a film by evaporating indium oxide mixed with a doping agent such as indium oxide, tin oxide, or antimony oxide in a vacuum without introducing a reactive gas, so the evaporation rate is slow. It is quick and does not require heating the substrate, so it can be applied to molded products with low heat resistance.However, since the film is mainly formed of a low oxide of metal indium, it is not necessary to use only Aoi adhesion. However, it was not possible to obtain a transparent conductive film with such characteristics, and an oxidation step was required, making this method industrially unfavorable. The present inventors have conducted extensive research into an industrially advantageous method for manufacturing molded products having excellent transparent conductive coatings containing indium oxide as the main component. Alternatively, it was discovered that by sputtering a metal or metal oxide in a gas containing oxygen, a molded product having a transparent torpor-conducting film with high transparency and high conductivity could be obtained, leading to the present invention. It is.

That is, the present invention provides a method for producing a molded article having a transparent conductive coating of a metal or metal oxide, in which a coating with low light transmittance mainly composed of a low oxide of indium metal is used.
1' on the surface is used as a substrate, one or more metals or metal oxides are sputtered in oxygen or a gas containing oxygen to form the metal or metal oxide on the coating [1}. While forming the coating '21 of the object, the coating '1'
This is a method for manufacturing a molded article having a transparent conductive coating, which is characterized by oxidizing a transparent conductive coating.

The features of the present invention will be explained in more detail.

The effects of the present invention are further characterized by the type of metal or metal oxide sputtered onto the coating 1', which is based on a low oxide of indium metal. The first method is when the main component of the metal or metal oxide sputtered onto the film [1} is indium metal or an oxide of indium metal.

According to the first method of the present invention, it is possible to easily obtain a molded article having a transparent conductive coating mainly composed of indium oxide and having excellent conductivity and high transmittance.

That is, in the first method of the present invention, the transparent conductive film containing indium oxide as a main component is formed by vacuum evaporation, which has a high film formation rate, and then by sputtering, which has a slow pus formation rate. , does not require the oxidation process as in the above-mentioned known method {3', and most of the film formation is performed by vacuum deposition, so the pus formation rate is much faster than the above-mentioned known method ``2'', and a heating device is not required. The device is simple because no equipment is required. Furthermore, the fact that heating is not required is particularly useful when the substrate is a molded product that does not have heat resistance. In the second method of the present invention, the metal or metal oxide to be sputtered onto the coating '1' mainly composed of a low oxide of indium metal is a certain metal other than indium metal or an oxide of indium metal. or the case of metal oxides.

On the surface of the molded product having the transparent conductive coating 1}, for example, reduction of moisture permeability, prevention of surface reflection, protection of the transparent conductive layer,
When forming a metal or metal oxide film {21 for the purpose of forming an electrode, etc., a conventional method uses a highly oxidized indium film as a transparent conductive film. A molded product having such a transparent conductive film on its surface is expensive. According to the second method of the present invention, it is sufficient to form another type of coating (2) depending on the purpose on the molded product having the inexpensive indium metal low oxide coating (1) on its surface; This is an industrially advantageous method because the oxidation of the film {11] can be carried out simultaneously with the formation of the film (2). Furthermore, the third method of the present invention is that transparent conductive pus with improved conductivity can be formed.

A transparent conductive film containing an indium metal oxide as a main component generally has a higher specific resistance than a metal, and is usually inferior in conductivity when compared to a metal thin film of the same thickness. However, metal thin films have poor transparency, and in order to be used as transparent conductive films, efforts must be made to improve transparency at the expense of conductivity. A laminate of these can be considered to compensate for the drawbacks of a transparent conductive film mainly composed of an oxide of indium metal and a metal thin film, and the method of the present invention is capable of providing the laminate at a low cost. That is, the method of the present invention involves sputtering a thin metal film in oxygen or an oxygen-containing gas onto a film containing a low oxide of indium metal as a main component, thereby forming a layer containing indium oxide as a main component and a metal layer. This provides a molded product having laminated transparent conductive coatings. In such a laminate, the layer that contributes to conductivity is mainly a metal layer, so the conductivity is much lower than that of a layer consisting mainly of indium oxide of the same thickness. Transparency is much improved compared to the case where As the base material for the molded product having the coating used in the present invention, any of organic polymer molded products, inorganic molded products, and composite molded products thereof can be used.

Examples of organic polymer molded products include thermoplastic resins such as polyethylene terephthalate resin, polyethylene naphthalate resin, acrylic resin, ABS resin, styrene resin, polyacetal resin, polyethylene resin, and polypropylene resin, epoxy resin, diallyl phthalate resin,
Examples include thermosetting resins such as silicone resins, unsaturated polyester resins, phenolic resins, and urea resins. Moreover, these may be used alone or in a mixture of two or more. Examples of inorganic molded products include glassy ones such as soda glass, borosilicate glass, and silicate glass;
Ceramics such as alumina, magnesia, zirconia, and silica may also be used, as well as metal oxides and various compound semiconductors.

When coating these molded substrates with a low oxide of indium metal, other elements may be mixed as impurities into the low oxide film to the extent that the desired effects of the present invention are not impaired.

Note that the low oxide of indium metal used in the present invention is represented by the following general formula. lnX○y
(0<y/x 1.5) Examples of methods for coating indium metal with low oxide include vacuum evaporation, sputtering, plasma spraying,
Vapor phase plating method, electroplating method, chemical coating method, and combination methods thereof. Although any method is possible, vacuum evaporation method, cathode sputtering method, etc. are particularly suitable from the viewpoint of uniformity of the formed film, ease of production, and ability to coat the nonconductor molded product.

At this time, the coating thickness of the indium metal low oxide depends on the conductivity and translucency of the transparent conductive film, the type of metal or metal oxide to be formed on it by sputtering, the coating thickness, and the coating formation speed. , cannot be determined uniformly because it cools down in relation to time, etc., but in many cases, it is approximately 3000 A or less from the viewpoint of adhesion and uniformity between the low oxide coating layer of indium metal and the molded product base material. It is thought that,
The preferred value is 2000 A or less in view of ease of oxidation, and 1500 A or less in view of the transparency of the resulting transparent conductive film.

On the other hand, the lower limit cannot be uniquely determined depending on the type and use of the metal or metal oxide to be coated thereon. From the viewpoint of oxidizing a low oxide of indium metal, a thinner one is preferable, but in order to form a continuous film, a thickness of 50A or more is particularly preferable. In the method of the present invention, the low oxide of indium metal formed on the surface of the molded product is oxidized to a high degree when the metal or metal oxide is sputtered in oxygen or plasma containing oxygen.

In order to provide this oxidizing effect during sputtering, the carrier gas must contain oxygen. The flow rate of the carrier gas, the degree of vacuum during sputtering, the discharge voltage, the discharge current, etc. vary depending on the type of target to be sputtered, coating thickness, distance between electrodes, etc., and cannot be determined uniquely. A molded product with a coating mainly composed of a low oxide of indium metal has sufficient heat resistance when the base is an inorganic molded product, so it can be placed anywhere during sputtering. However, exposure to plasma is particularly desirable. During sputtering, the temperature of the molded product increases as it is exposed to plasma, and the increase in temperature promotes oxidation of low oxides of indium metal. If the substrate is an organic molded product, it often does not have sufficient heat resistance.
Sufficient consideration must be given to the position during swerving. −
Although exposure to the plasma is not practical, close enough proximity to the plasma is desirable for oxidation of low oxides of indium metal and pus formation of metals or metal oxides. If a magnetron sputtering device called a low-temperature sputtering method is used, the substrate is not directly exposed to plasma, which is particularly preferable when the substrate is an organic molded product. Generally, film formation by sputtering involves depositing sputtered metal or metal oxide on a substrate, and the surface of the substrate is covered by the deposition.

Therefore, it is considered that after the metal or metal oxide forms a continuous film, there is no longer mutual interference between the substrate and the plasma. However, the layer '1', which is mainly composed of a low oxide of indium metal, is not formed even before or during the process of forming a continuous film of metal or metal oxide on it.
Alternatively, even after it is formed, oxidation progresses and it reaches a point where it has sufficient performance as a transparent conductive film. The type of metal or metal oxide to be sputtered onto the layer mainly composed of a low oxide of indium metal is not particularly limited.

Any material that can be sputtered may be used, and is selected depending on the purpose. Further, it may be an alloy, a mixture, or a compound of two or more metals or metal oxides, and is appropriately selected depending on the purpose. For example, in order to obtain a thick transparent conductive film mainly made of indium metal oxide, indium metal or an alloy of indium metal with small amounts of tin, cadmium, tungsten, molybdenum, etc., or indium oxide and Mixtures of tin oxide, cadmium oxide, tungsten oxide, molybdenum oxide, etc. are used.

On the layer '1' mainly composed of indium metal oxide,
Examples of metals used to obtain a transparent conductive film with improved conductivity by forming a layer with another type of metal or metal oxide include gold, silver, copper, nickel, chromium, platinum, palladium, Any metal can be used, such as titanium.

Particularly preferred for this purpose are metals that are inert to oxygen, such as noble metals such as gold, platinum, and palladium. There are also other types of metals, or groups of metal oxides, that are used for the same purpose. Examples include titanium, tin, cadmium, zirconium, or oxides thereof, which do not lose their electrical conductivity even when coated with an oxide. Furthermore, alloys, mixtures, and compounds of two or more of these metals or metal oxides may be used. A layer mainly composed of a low oxide of indium metal {a layer 2 of another metal or metal oxide} may be formed on the layer 11 for purposes other than imparting conductivity.

For example, a layer {21 of silicon dioxide, titanium oxide, aluminum oxide, etc. is formed for the purpose of protecting the layer {1', improving moisture permeability, antireflection, insulation, etc. As mentioned above, the layer mainly composed of indium metal {1}
The metal or metal oxide used to form the layer '21 thereon is not particularly limited, and may be a compound, mixture, or alloy of two or more thereof.

According to the method of the present invention, for example, a molded article having a coating mainly composed of a low oxide of indium metal on its surface is generally obtained by a vacuum coating method, but by improving the equipment, the vapor deposition and sputtering can be performed. It can also be carried out in the same vacuum chamber.

In addition, when the molded substrate is in the form of a film, it is a highly productive method for manufacturing a transparent conductive film that can be manufactured continuously, for example by continuously moving it in an appropriately partitioned vacuum chamber. . Particularly from the viewpoint of heat resistance, this method can be applied to a wide range of molded products not found in conventional methods. Furthermore, this is an industrially established method for producing a molded article in which another layer is formed on a transparent conductive film made of an oxide mainly containing indium metal. The present invention will be explained below by giving examples.

Example 1 A film of indium oxide having a thickness of about 350 Å was formed on a polyethylene terephthalate film having a thickness of 75 µm by a conventional vacuum deposition method.

The obtained vapor deposited film was a black conductive film made of a low oxide of indium metal and had a surface resistance of 57,000/base and a light transmittance of 36% at 60°. Various metals were sputtered onto this black conductive film in an argon gas containing 20% oxygen.

Sputtering was performed using a flat magnetron type target with a diameter of 4 inches. Table 1 shows the sputtering conditions and the properties of the obtained transparent conductive film. The properties of the coating simultaneously prepared on the polyethylene terephthalate film are shown in Table 1 for comparison. The surface resistance value and transmittance of the transparent conductive film obtained by oxidizing the same black conductive film in air at 180 pm for 1 hour were 5.
200', and it is clear that a transparent conductive film with improved conductivity was obtained. Table 1 *Transmittance of coating at 60nmK** Values in () are values for sputtering coating only (Example)
2 A low oxide film of indium metal was formed on a glass slide under exactly the same conditions as in Example 1.

This black conductive film was sputtered with the metals shown in Table 2 in an argon gas containing 20% oxygen. Sputtering was performed using a bipolar sputtering device with a diameter of 10 mm. The distance between the electrodes was 6 mm, and a glass slide with a black conductive coating was placed on the anode. The results obtained are shown in Table 2. Table 2 *Transmittance of the coating at 60 nmK** Values in parentheses are values for the sputterlink coating only Example 1
, 2, the sputtered coating forms an oxide coating excluding Au.

As shown in Tables 1 and 2, the low oxide film of indium metal is oxidized during sputtering to form a transparent conductive film, and by laminating a transparent conductive layer on top of the layer, it is possible to improve the properties of the indium metal. A transparent conductive film is formed. Example 3 A mixture of indium oxide and tin oxide in an amount of 7.5% by weight was deposited on a 75 μm thick polyester film and a transparent acrylic slope by a conventional vacuum deposition method.

The obtained vapor deposited film is a film mainly composed of a low oxide of indium metal, and has a film thickness of 280A, a surface resistance of 44000/average,
It was a black conductive film with a transmittance of about 42% for 600 yen light. Various oxides were sputtered onto this black conductive film in argon gas with an oxygen concentration of 20%, and the results shown in Table 3 were obtained.

Table 3 * The part that will become the electrode for resistance measurement was masked to prevent the formation of a sputtering film. o** Transmittance of the film at 60 nmK.

Note that the same equipment as in Example 1 was used for sputtering.

All sputtered metal oxide films are insulators. Furthermore, there was no difference when the substrate was a polyester film or an acrylic board. Comparative Example 1 For comparison, Au, Ag, and Ti were sputtered in pure argon gas, but almost no improvement in the conductivity and transparency of the low oxide film of indium metal was observed.

When I tried sputtering Si02 in the same way,
Although the transparency was improved by 12%, it was not practical as a transparent guiding film. In this case, it is thought that oxygen resulting from the decomposition of Si02 contributes to the oxidation of the low oxide of indium metal. From the above results, it is clear that the carrier gas for sputtering must be oxygen or a gas containing oxygen. Furthermore, for comparison, a film in which indium metal was vacuum-deposited to a thickness of 200Δ was sputtered under the same conditions as in Example 1, but the indium metal was hardly oxidized and no transparent guiding film was obtained.

Claims (1)

[Claims] 1. In a method for manufacturing a molded article having a transparent conductive coating of a metal or metal oxide, a molded article having a coating (1) with low light transmittance mainly composed of a low oxide of indium metal on its surface is used as a substrate. , in oxygen or a gas containing oxygen, 1
Sputtering a seed or two or more metals or metal oxides to form a film (1) of the metal or metal oxide on the film (1).
2) A method for producing a molded article having a transparent conductive film, characterized in that the film (1) is oxidized while forming the film (1).