JPH0725615A - Heat-resistant transparent electrically conductive window material - Google Patents

Abstract

PURPOSE:To obtain a window material usable even under a high temperature condition without causing the variation of the electrical conductivity of the transparent conductive layer. CONSTITUTION:This heat-resistant transparent electrically conductive window material is provided with an indium oxide-based transparent conductive layer 2 formed by applying a solution containing an organic indium compound to a surface of a heat-resistant transparent substrate 1 and subjecting the solution to thermal decomposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant transparent conductive member having a transparent conductor layer, and particularly to a window material used at high temperature in an electric furnace or the like, a window material for airplanes, automobiles, etc. The present invention relates to a heat-resistant transparent conductive window material applied as.

[0002]

2. Description of the Related Art As transparent conductor layers, metal thin films such as gold and silver, and metal oxides such as tin oxide and indium oxide are used.
Generally known (Thin Film Handbook: Japan Society for the Promotion of Science). Further, as a method for producing the indium oxide transparent conductor layer, a sputtering method and a vapor deposition method are generally well known (Electroceramics '85 .5 May, p. 2).
3 (1985)). In addition, Japanese Patent Publication No. 54-28396
The publication discloses a method for producing an indium oxide film by a coating pyrolysis method. However, there is no member having heat resistance, transparency, and conductivity.

[0003]

For example, in the case of a metal thin film, the mechanical strength is weak because the film thickness is made thin in order to increase the permeability. When using the indium oxide transparent conductor layer produced by the sputtering method or the vapor deposition method under high temperature conditions,
There was a drawback that the conductivity of the transparent conductor was changed by heat (see Surface Technology vol.43, No.12, p.98 (1992)).
Therefore, when used under high temperature conditions, it is difficult to use the transparent conductor layer produced by the conventional sputtering method or vapor deposition method. Further, Japanese Patent Publication No. 54-28396 discloses a method for producing an indium oxide coating film by a coating pyrolysis method. Application of the transparent conductor by the coating pyrolysis method as a heat resistance or a heat resistant transparent conductive window material. Nothing is said about the method.

In view of the above problems of the prior art, an object of the present invention is to provide a heat resistant transparent conductive window material which does not change its conductivity under high temperature conditions.

[0005]

A heat-resistant transparent conductive window material according to the present invention is an indium oxide-based transparent conductor formed by applying and pyrolyzing a solution containing an organic indium compound on a heat-resistant transparent substrate. It is characterized by having layers.

[0006]

The transparent conductor layer formed by applying an organic indium compound-containing solution and thermally decomposing does not decrease in conductivity even if it is heat-treated, so that it can be used under high temperature conditions. Become. Therefore, it can be used as a heat resistant window material. In this case, since the heat treatment is performed at the time of manufacturing, the crystallinity and the like do not change due to the subsequent heat treatment, so that the conductivity is not changed.

[0007]

EXAMPLES Next, the present invention will be described in more detail with reference to the accompanying drawings with respect to examples of the heat-resistant transparent conductive window material of the present invention.

Examples of the heat resistant transparent substrate used in the present invention include quartz, non-alkali glass, borosilicate glass and the like. The thickness of the transparent substrate is not particularly limited.
Further, as the organic indium compound used for forming the transparent conductor layer, (R ₁ COO) ₃ In [wherein R ₁ is
Represents an alkyl group having 4 to 16 carbon atoms], (CH ₃ C
OCHCOCH _{3) 3} In, and the like.

In addition to the organic indium metal compound, an organic tin compound may be added to the organic indium metal compound-containing solution formed on the transparent conductor film in order to improve the conductivity. Examples of the organic tin compound include (R ₂ C
OO) ₂ Sn [wherein R ₂ represents an alkyl group having 4 to 16 carbon atoms], (CH ₃ COCHCOCH ₃ ) ₂ Sn
Etc. The addition amount of the organic tin compound is preferably 0 to 40% in terms of tin / indium molar ratio. If the molar ratio of tin is higher than this, the conductivity becomes low.

As a solvent for the organic indium compound-containing solution, aliphatic hydrocarbons such as octane, decane, dodecane and tridecane are selected from the viewpoint of wettability to a transparent substrate such as quartz, non-alkali glass and borosilicate glass. Although it is particularly desirable, any solvent having solubility for the organic indium compound, such as aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride, may be used. The concentration of the solution is preferably in the range of solid content ratio of 5 to 50%.

As an additive, the solution is thickened,
Cellulose derivatives such as ethyl cellulose and nitrocellulose may be added to improve the adhesion to the substrate, or unsaturated carboxylic acids such as linoleic acid and linolenic acid may be added to improve the wettability with the substrate. The addition amount is preferably in the range of 0 to 50%.

Further, another film such as a protective film may be laminated on the transparent conductor layer. The solvent of the organometallic compound-containing solution may be any solvent that has solubility for the organometallic compound. For example, octane, decane, dodecane, aliphatic hydrocarbons such as tridecane, toluene, aromatic hydrocarbons such as xylene, methylene chloride, halogenated hydrocarbons such as chlorobenzene, ethanol, butanol, terpineol, alcohols such as ethylene glycol, Examples thereof include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethers such as diethyl ether and tetrahydrofuran, ethers such as ethyl acetate and benzyl acetate. The concentration of the solution is preferably in the range of solid content ratio of 5 to 50%. When a commercially available metal resinate is used, it may be diluted with the above solvent, but the metal resinate may be used as it is.

Further, as an additive, the solution is thickened,
A cellulose derivative such as ethyl cellulose or nitrocellulose may be added to enhance the adhesion to the substrate, or an unsaturated carboxylic acid such as linoleic acid or linolenic acid may be added to improve the wettability with the substrate. . The addition amount is preferably in the range of 0 to 20%.

As a method of applying the solution containing the organic indium compound, for example, bar coating, spin coating,
Examples thereof include spray coating, screen printing, dip coating and the like.

The method of pyrolyzing the coating film of the solution containing the organic indium compound is carried out in an electric furnace or the like at a temperature of 400 to 1500 ° C. for 30 minutes to 10 hours. When the baking temperature is low, the thermal decomposition of the organic indium compound is insufficient and the conductivity is low, and when the baking temperature is high, the substrate component penetrates into the indium oxide film to lower the conductivity. The firing time may be 10 hours or more, but it is not particularly required to be 10 hours or more. Examples of the firing atmosphere include air, nitrogen, an oxygen flow, nitrogen, an oxygen substitution atmosphere, and a reduced pressure atmosphere. The film thickness of the fired oxide is preferably 0.05 to 10 μm. If it is thinner than this, the conductivity is low, and if it is too thick, the transparency deteriorates. Further, in order to increase the film thickness, application of the solution containing an organic indium compound and thermal decomposition may be repeated.

Next, an embodiment of the heat-resistant transparent conductive window material according to the present invention will be described.

[Example] In order to manufacture a heat-resistant transparent conductive window material having a cross-sectional structure schematically shown in FIG. 1 of the accompanying drawings as an example of the present invention, (C ₈ H ₁₇ COO) ₃
0.5 g of In and 0.013 g of (C ₈ H ₁₇ COO) ₂ Sn are dissolved in 1.857 g of dodecane. This solution was applied to the quartz substrate 1 with a wire bar (# 10), dried at 45 ° C for 30 minutes, and then baked in air at 800 ° C for 1 hour to give I
An n ₂ O ₃ / SnO ₂ film 2 is obtained. This film 2 was a transparent conductor layer, had a sheet resistance of 0.8 kΩ / □, a visible light transmittance of 95%, and a film thickness of 0.2 μm.

The heat-resistant transparent conductive window material having this transparent conductor layer 2 was used as a window material for an electric furnace. 3 at 900 ° C
After use for a period of time, no change was observed in the resistance value and appearance of the transparent conductor layer.

Next, in order to confirm the effect of the present invention,
A comparative example will be described in which a window member having a similar structure is manufactured by a conventional method so as to be compared with the above-mentioned [Example] according to the present invention.

[Comparative Example] On a quartz substrate 1, In ₂ O ₃ / S was added.
A 0.2 μm thick ITO transparent conductor film is formed by vacuum evaporation of nO ₂ . The resistance value of this film was 0.2 kΩ / □, and the visible light transmittance was 94%. The heat-resistant conductive window material containing this transparent conductor film was used as a window material for an electric furnace. 3 at 900 ° C
The resistance value of the transparent conductor layer after use for 1.5 hours is 1.5 kΩ / □
Became high.

Further, an ITO transparent conductor film of vacuum vapor deposition (conventional method) and an ITO transparent conductor film of coating pyrolysis method (present invention).
When comparing the heat resistance of the
The resistance value of the O transparent conductor film does not change by heat treatment, whereas the resistance of the vacuum vapor deposition ITO transparent conductor film increases. In addition to the vacuum-deposited ITO transparent conductor film, the ITO transparent conductor film produced by the sputtering method also showed a phenomenon in which the resistance value was increased by the heat treatment similarly to the vacuum deposition.

[0022]

As described above, according to the present invention, a solution containing an organic indium metal compound is applied onto a transparent substrate by coating or printing, and then thermally decomposed to form an indium oxide-containing transparent conductor film. Since the transparent conductor film is formed using a relatively high temperature process, it has an effect that it can be used as a heat resistant transparent conductive window material even under high temperature conditions without changing its conductivity. .

Further, according to the present invention, by forming the transparent conductor layer by the coating pyrolysis method, it is possible to easily increase the area without using a complicated apparatus such as sputtering or vapor deposition, and to perform etching. It is possible to prepare a patternable transparent conductor layer by a simple process such as coating or screen printing without any process. Further, the heat-resistant transparent conductive window material including the transparent conductor layer produced by the coating pyrolysis method can be laminated with another film by heat treatment or the coating pyrolysis method.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing the structure of a heat-resistant transparent conductive window material as one embodiment of the present invention.

FIG. 2 is a view showing a resistance change between a conventional method and a transparent conductor film according to the present invention in comparison.

[Explanation of symbols]

 1 Quartz substrate 2 Transparent conductor layer

Claims (1)

[Claims] 1. A heat-resistant transparent conductive window material, comprising an indium oxide-based transparent conductor layer formed by applying and thermally decomposing an organic indium compound-containing solution on a heat-resistant transparent substrate.