JPS61253722A - Formation of light transmitting conductive film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for forming a light-transmitting conductive film on a transparent substrate.

<Prior art> Conventional methods for forming a light-transmitting conductive film on a transparent substrate such as glass or plastic film include: 1) coating a noble metal such as gold, platinum, or palladium on the transparent substrate; (2) A method of coating a metal oxide such as indium oxide, indium tin oxide, or cadmium tin oxide on the transparent substrate is generally employed.

<Problems to be Solved by the Invention> The light-transmitting conductive film obtained by the above method (■) generally has a transmittance of 80% or more for visible light, which is excellent, but the conductivity is low per unit area. There is a problem that the sheet resistance is 100Ω or more, which is slightly inferior.

In addition, the light-transmitting conductive film obtained by the above method (■) is
The conductivity is 100Ω or less in sheet resistance per unit area,
Although excellent, there is a problem in that the transmittance for visible light is generally less than 80%, which is somewhat inferior.

In general, a high-quality light-transmitting conductive film is required to have a visible light transmittance of 80% or more and a conductivity of 102Ω or less in terms of sheet resistance per unit area. The obtained light-transmitting conductive film was also not fully satisfactory in terms of both transmittance and conductivity.

Furthermore, a light-transmitting conductive film obtained by coating with a noble metal has excellent properties such as good corrosion resistance and an electromagnetic shielding effect. therefore,
In order to increase the light transmittance without sacrificing these excellent properties, the coating film thickness can be made thinner, but the conductivity of the film may be drastically reduced by making it thinner. However, there has been a problem in that it is difficult to form a film having excellent properties in both light transmittance and electrical conductivity.

Another problem is that the light-transmitting conductive film obtained by coating with a noble metal is expensive to manufacture because the raw material is the noble metal.

This invention was made in view of the above problems,
The object of the present invention is to provide a method for forming a light-transmitting conductive film that is excellent in both light transmittance and electrical conductivity.

<Means for Solving the Problems> In order to achieve the above object, the method for forming a light-transmitting conductive film of the present invention includes forming a metal base film on a transparent substrate, and then forming a noble metal film on the metal base film. is formed and then irradiated with ionizing radiation.

As the above-mentioned transparent substrate, glass, plastic film, etc. can be used, and the gold corrosion film can be produced using physical vapor deposition methods such as vacuum evaporation method, ion plating method, and sputtering method using copper, gold, silver, and platinum as raw materials. Phase deposition method, electroplating,
It is formed by chemical plating or the like, and α rays, γ rays, X rays, electron beams, etc. can be used as the ionizing radiation.

With the above formation method, a metal base film made of copper, gold, silver, platinum, etc. is formed on a transparent substrate such as glass or plastic film by a method such as vapor deposition, electroplating, or chemical plating. On this film, a noble metal film made of gold, silver, platinum, palladium, iridium, etc. is formed by vapor deposition, electroplating, chemical plating, etc. to form a double structure. By irradiating with ionizing radiation such as α-rays, γ-rays, X-rays, and electron beams, it is possible to obtain a light-transmitting conductive film with excellent light transmittance and conductivity without causing oxidation on the surface. can.

<Example> Hereinafter, this will be explained in detail using examples.

A copper film as a gold base film is deposited on a transparent substrate such as glass or plastic film using a physical vapor deposition method of 50 to 10%.
00A, preferably to a thickness of 100 to 500A, and then a gold film as a noble metal film is formed on this copper film to a thickness of 10 to 30A.
By forming the film to a thickness of 00A, preferably 10 to 100A, a double-structured film can be obtained. After that, by irradiating this double-structured film with 5 to 50 Mrad of ionizing radiation, the transmittance to visible light becomes 80% or more, the electrical conductivity becomes 100Ω or less in sheet resistance per unit area, and the transmittance to light becomes 80% or more. It was possible to obtain a light-transmitting conductive film that exhibits excellent properties in both , and conductivity.

With the above method, the metal base film as the main part of the light-transmitting conductive film is copper, and it is possible to easily produce a light-transmitting conductive film with excellent light transmittance and conductivity while keeping manufacturing costs low. I was able to get it.

In the above example, the thickness of the deposited film was set to 100 to 5QO.
Although A is used, it can be selected as appropriate depending on the metal used, the type of material used, and the wavelength of light to be transmitted.

Further, although gold is used as the noble metal, silver, platinum, palladium, iridium, etc. may also be used, and since they do not oxidize in the air, they can exhibit good light transmittance and conductivity.

Furthermore, as the ionization number rJJPA, an electron beam is preferable from the viewpoint of industrial efficiency, and the acceleration voltage of the electron beam is 0.
．． It may be in the range of 1 to 5 MV. However, it is more preferably 01 to 0.5 MV.

Experimental Example 1 Ion-blating method (vacuum degree 2x10-4 Torr, r f: 13.56
Copper was evaporated to a thickness of 300 mm using MIIZ, 200 W), and the RF sputtering method (vacuum degree 5x) was applied to this evaporated film.
1O-4T orr, , rf: 13.56
Gold is deposited to a thickness of 50A using MB2, 500W) to form a double-structured deposited film. and,
This double-structured vapor deposited film was irradiated with 48M rad of electron beam with an acceleration voltage of 300KV, and the transmittance for visible light was 8.
A light-transmitting conductive film having a sheet resistance of 3% and a sheet resistance per unit area of 33Ω was obtained.

The transmittance for visible light after electron beam irradiation and the sheet resistance per unit area were 22% and 47Ω, respectively, before electron beam irradiation, which were significantly improved, as is clear from the comparison. A light-transmitting conductive film having good light transmittance and conductivity could be obtained.

Experimental example 2 Glass plate with a thickness of 1.5ml (visible light transmittance 93%)
on top of the ion brating method (vacuum degree 2X 10'
Torr,, r f : 13.56 MII2,2
Copper was deposited to a film thickness of 200 mm using 00 W), and gold was deposited on this evaporated film to a thickness of 5 mm using the same ion blating method as above.
A double-structured deposited film is formed by depositing to a thickness of zero. Then, an accelerating voltage of 4
Irradiated with 00KV electron beam at 36M rad, the transmittance to visible light was 88%, and the sheet resistance per unit area was 45%.
A light-transmissive conductive film of Ω could be obtained.

<Effects of the Invention> As described above, the present invention achieves optical transparency and conductivity by a simple method of forming a double-structured film consisting of a base metal film and a noble metal film and then irradiating it with ionizing radiation. This has the unique effect of being able to form a light-transmitting conductive film having excellent properties on both sides.

Claims (1)

[Claims] 1. A method for forming a light-transmitting conductive film, which comprises forming a metal base film on a transparent substrate, forming a noble metal film on the metal base film, and then irradiating with ionizing radiation. .