JPH02216752A - Tube-form glass with transparent conductive oxide thin film and its manufacture - Google Patents

Abstract

PURPOSE:To make it possible to adopt a spreading method and to obtain a desired resistance value and the thickness by composing a transparent conductive oxide thin film with a composite of indium oxide and tin oxide when such a transparent conductive oxide membrane is attached to the inner surface and/or at least to a part of the outer surface of a tube-form glass base. CONSTITUTION:When a transparent conductive oxide thin film is spread to a tube-form glass base to compose an instant lighting type fluorescent lamp, a composite of indium oxide and tin oxide is used, and it is formed by a spreading method. In this case, the thickness of the thin film is made in a scope 0.01-2mum, its surface resistance value is made in a scope 1KOMEGA/square-30MOMEGA/ square, and the whole light transmissibility of the tube-form glass is made 80% or higher. And the surface of the oxide thin film is protected by a transparent protective layer. The glass tube may be a straight tube or a bending tube, and as the spreading method, either a soak-and-pickup method, an intratube filling-and-flowing method, a spray method, or an outer surface printing is available.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tubular glass coated with a transparent conductive oxide thin film and a method for manufacturing the same. More specifically, the present invention is coated with a transparent conductive oxide thin film made of a composite oxide of indium oxide and tin oxide, and can be suitably used in manufacturing an instant-on type fluorescent lamp. The present invention relates to a tubular glass that can be produced and a method for manufacturing the same.

Technical background of the invention and its problems Transparent conductive oxide thin films have the characteristics of high transmittance of visible light and the ability to control conductivity over a wide range. It can be used to display devices such as liquid crystal displays, plasma displays and fluorescent display tubes, transparent electrodes such as touch panels and solar cells,
Anti-fog for aircraft, automobile windows, refrigeration showcases, etc.
It is widely used as a transparent heating element for preventing swimsuits and as a heat-reflecting film for automobile and architectural windows.

Conventional methods for forming such oxide thin films include vacuum evaporation, sputtering, and CVD (C
heo+1cal Vapor Deposition
) method and other gas phase methods are used. For example, the Special Public Interest Publications Act,
No. 19279 and Japanese Unexamined Patent Publication No. 63-15784 disclose a method of forming a transparent conductive coating on a glass tube by employing a vapor phase method.

However, is it possible to achieve transparent conductivity by using a vapor phase method on a glass tube as described in the above publication? In method 1 of forming a film, it is necessary to create a fairly high degree of vacuum inside the device, and in addition, unlike a plate-shaped substrate, when using a cylindrical glass substrate, the device must be adapted to the shape of the substrate, etc. This requires many technical and economical difficulties.

Recently, as a method to solve the above-mentioned problems in the gas phase method, a solution in which transparent oxide thin film-forming components are dissolved or dispersed in an organic solvent, etc. is prepared, and this solution or dispersion is applied by a spray method or a dipping method. Also attracting attention is a method of coating a substrate glass using a screen printing method or the like and then heating it. By heating the component for forming a transparent conductive oxide thin film applied in this manner, this component is thermally decomposed or oxidized to form a transparent conductive oxide thin film.

However, transparent conductive oxide thin films formed by coating methods are less stable against temperature changes than thin films obtained by vapor phase methods, so their use is actually limited to very limited fields. It's just that it's being done.

Incidentally, once a fluorescent lamp has been lit, it is possible to continue lighting it at a low voltage of about 100 to 200V, but when starting it up, it is necessary to generate a high voltage to start lighting it. Methods of generating high voltage at startup include using a glow lamp, and forming a conductive layer on a fluorescent tube and causing this conductive layer to act as a capacitor to generate high voltage. It is taken. In particular, recently, fluorescent lamps provided with a conductive layer have been attracting attention as industrial fluorescent lamps.

For example, Japanese Patent Publication No. 47-19279 discloses that a conductive material made of tin-antimony-based oxide is formed on the inner surface of a glass tube using a CVD method so that the conductivity decreases continuously from the center to both ends. An instant-on fluorescent lamp using a glass tube coated with a thin film is disclosed. Also, JP-A-63
Publication No. 157874 discloses a method of coating the inner surface of a straight material glass tube with a conductive film of tin oxide using a laser beam using a CVD method. The fluorescent lamp used is disclosed.

However, when using the vapor phase method, in order to accommodate the tubular glass and form a tin-antimony-based oxide layer,
It is necessary to maintain a very high degree of vacuum in the system, and the precursor for forming the tin-antimony oxide must be gasified and uniformly supplied to the surface of the glass tube. Furthermore, since the properties of the precursor for forming the tin-antimony-based oxide layer change when it comes into contact with water, it is also necessary to completely remove water from the reaction system.

Therefore, when forming a tin-antimony-based oxide layer using a vapor phase method, a device with extremely high airtightness is used, and furthermore, it is necessary to It is necessary to modify the gas phase reactor. Also,
The oxide layer formed as described above is relatively strong (hard).
After forming this oxide layer, this oxide layer may be damaged during further firing, and the phosphor coating process And the firing operation must be done very carefully. Furthermore, this tin-antimony-based oxide easily combines with the sodium in the glass, so it is necessary to take measures to prevent the reaction with the sodium component that leaches from the glass when the phosphor is applied and fired. be. Further, the above method has a problem in that a curved tubular glass cannot be used as a substrate.

For this reason, the fluorescent lamp itself is very expensive, making it unsuitable for use as a household fluorescent lamp, for example, and therefore its current popularity as a household fluorescent lamp is extremely low.

Further, as a method different from the method of forming a conductor layer as described above, a method has been proposed in which a metal tape such as aluminum is pasted in the longitudinal direction on the outer surface of the fluorescent tube. Although this method is simple, it looks bad and is dangerous because contact with this metal tape will result in electric shock. Furthermore, such metal tapes are generally attached to the outer surface of glass tubes, and there is a problem in that it is relatively difficult to attach them to curved tubes.

OBJECTS OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above, and provides a transparent conductive oxide having characteristics particularly suitable as a tubular glass for instant-lighting fluorescent lamps. It is an object of the present invention to provide a tubular glass on which a thin film is formed and a method for manufacturing the same.

More specifically, the present invention utilizes a wet coating method that provides excellent thin film properties such as uniformity and hardness of the deposited thin film, and also allows easy control of these properties. Complex (hereinafter referred to as indium-
The object of the present invention is to provide a tubular glass coated with a thin film made of tin oxide (sometimes referred to as tin oxide) and a method for manufacturing the same.

A further object of the present invention is to provide a method by which a transparent conductive oxide wave film can be formed on a glass substrate of a curved tube without using any special equipment.

Summary of the Invention The tubular glass with a transparent conductive oxide thin film according to the present invention comprises a tubular glass substrate and a conductive oxide thin film formed on at least a portion of the inner surface and/or outer surface of the substrate. The tubular glass with an oxide thin film is characterized in that the transparent conductive oxide thin film is made of a composite of indium oxide and tin oxide.

Further, the method for manufacturing a tubular glass with a transparent conductive oxide thin film according to the present invention includes a tubular glass substrate, an inner surface of the substrate, and/or a tubular glass substrate.
or a conductive oxide thin film formed on at least a portion of the outer surface of the tubular glass, the substrate is coated with a composite of indium oxide and tin oxide or The method is characterized in that a coating solution for forming a transparent conductive oxide thin film containing the precursor is applied, and then dried and/or baked.

DETAILED DESCRIPTION OF THE INVENTION Next, the tubular glass with a transparent conductive oxide thin film and the method for manufacturing the same according to the present invention will be specifically described.

First, the tubular glass with a transparent conductive oxide thin film according to the present invention will be explained.

The tubular glass with a transparent conductive oxide thin film according to the present invention consists of a tubular glass substrate and a transparent conductive oxide thin film, and the transparent conductive oxide thin film is made of a composite of indium oxide and tin oxide. . The thickness of the thin film is usually 0.01 to 2 μm, and the surface resistance value is usually 1
KΩ/□ to 30 MΩ/□, and the total light transmittance of the tubular glass with a transparent conductive oxide thin film is usually 80% or more.

The tubular glass with a transparent conductive oxide thin film of the present invention can be produced, for example, by coating a tubular glass substrate with a coating liquid containing an indium compound and a tin compound that can form a transparent conductive oxide thin film. It can be produced by converting an indium compound and a tin compound into oxides.

There is no particular restriction on the diameter or length of the tube of the tubular glass substrate used in the present invention, and specific examples of such a tubular glass substrate include tubes with a diameter of 15 mm to 15 mm, which are widely used in homes and offices. 35 mm, length 100
Tubular glass for straight fluorescent lamps with a diameter of about 1,500 m+i can be mentioned.

In addition to the tubular glass for straight fluorescent lamps as mentioned above,
Irregularly shaped tube glass, such as curved tube glass and rectangular parallelepiped tube glass, which are often used for decoration, can also be used as the substrate. These tubular glasses are usually alkali-containing glasses with a relatively low melting point, but high-purity glasses with a low alkali content can of course also be used as the substrate.

Conventionally, the transparent conductive oxide thin film coated on the inner surface of glass tubes used in instant-light fluorescent lamps has been made of tin oxide,
Tin-antimony oxide was used. However, tin-antimony oxide and the like have problems such as a gradual reaction with sodium contained in the tubular glass substrate, resulting in a change in resistance value. In contrast, in the present invention, since the transparent conductive oxide thin film is formed of an indium-tin composite oxide, the resistance value of the transparent conductive oxide thin film can be easily increased compared to tin-antimony oxide. Furthermore, it is possible to solve the problem that the transparent conductive oxide thin film deteriorates due to the alkaline component contained in the tubular glass substrate.

In the present invention, the transparent conductive oxide film is prepared by preparing a composite oxide consisting of indium oxide and tin oxide in advance,
A method of dispersing this oxide in an organic solvent containing a suitable binder and coating the obtained dispersion on a substrate, or a method of heating a composite oxide consisting of the above-mentioned indium oxide and tin oxide. A compound oxide can be formed by preparing a coating liquid in which a precursor capable of forming a substance is dispersed or dissolved in an organic solvent, applying this coating liquid onto a substrate, and then generating a composite oxide on the substrate. .

Here, the indium-tin composite oxide can be manufactured by using, for example, a CVD method. In addition,
When an indium-tin composite oxide is prepared in advance and used in this way, the average particle diameter of this composite oxide is 0.
It is preferably within the range of 0.01 to 0.2 μm.

Further, a precursor capable of forming an indium-tin composite oxide is produced from an indium compound and a tin compound. Examples of such indium compounds include indium nitrate,
Inorganic indium compounds such as indium sulfate and organic indium compounds containing groups such as carboxyl, alkyl, or alkoxyl groups are used. Further, as the tin compound, tin halide, tin carboxylate, etc. are used. Specifically, a coating solution containing an indium compound and a tin compound as described above is prepared by applying a dopant containing a hydrolyzable indium compound, a carboxylic acid compound, and a tin compound to a dopant containing water. By dissolving the indium compound in an organic solvent to prepare a solution, partially hydrolyzing the indium compound contained in this solution, and adding a β-diketone compound at that stage to suppress the progress of the hydrolysis reaction. can be manufactured.

In the above coating liquid, it is preferable that the indium compound and the tin compound as a doping agent are used in an amount such that ■n203/5nO7 (weight ratio) is 4 to 99, particularly 5 to 20.

Such a coating liquid is disclosed in a patent application filed in 1986 by the applicant.
It is described in detail in the specification of No. 2-294330.

In addition, in the present invention, as the above-mentioned coating liquid,
Commercially available coating liquids can also be used.

An example of such a coating liquid is ELCOM-YN-4.
Examples include indium-tin coating liquids such as 00 (manufactured by Catalysts & Chemicals Co., Ltd.).

In the present invention, it is preferable to use a coating liquid containing the above-mentioned precursors.

To apply the above coating liquid to a tubular glass substrate,
Possible methods include the immersion pulling method, the pipe filling method, the spray method, and the printing method on the outside of the pipe.

When forming a transparent oxide conductive thin film using such a coating method, by adjusting the concentration and viscosity of the coating liquid, the coating thickness of the coating liquid, the coating method, the temperature during coating, etc.
The resistance value of the resulting transparent oxide conductive thin film can be controlled.

In the present invention, the coating liquid for forming a transparent conductive thin film as described above can be applied to either the inner or outer surface of the tubular glass substrate, or can be applied to both surfaces. Furthermore, the above-mentioned coating liquid does not necessarily need to be applied all over the inner or outer surface of the tubular glass substrate; for example, when used as a fluorescent tube,
The coating liquid for forming a transparent conductive oxide thin film may be applied so as to connect at least one end and the other end of the tube.

A transparent conductive oxide film can be formed on a substrate by drying the coating liquid after coating it on the substrate in this way or by baking it after drying.

That is, in the present invention, depending on the type of coating solution, the tubular glass coated with the coating solution for forming a transparent conductive oxide thin film can be fired without going through a drying process, but it is possible to bake it after drying. By this, a transparent conductive oxide thin film with particularly excellent adhesion can be formed.

The drying temperature in this case may be any temperature that can remove the solvent component in the coating film, and is usually from room temperature to 200°C. Further, the drying time can be appropriately set in consideration of the drying temperature, but is usually 0.1 to 2 hours.

After drying the transparent conductive oxide thin film thus formed on the substrate, or without drying, it is fired.

The firing temperature is usually 300 to 600°C, preferably 40°C.
The temperature is 0 to 550°C.

By baking in this manner, a transparent conductive oxide film is formed, and the adhesion between the transparent conductive oxide thin film and the tubular glass substrate is improved.

In the present invention, drying and firing can be performed in separate steps, or, for example, the temperature can be raised continuously from room temperature to the firing temperature to perform firing while drying. By firing in this manner, when a precursor is used, the precursor is oxidized to become an indium-tin composite oxide.

When the tubular glass of the present invention is used as a fluorescent tube, the fluorescent paint can be applied to the inner surface of the glass tube before or after firing. However, if a phosphor coating solution is applied after the coating solution for forming a transparent conductive oxide thin film is applied, but before the indium and tin components change into a composite oxide, depending on the type of phosphor, the phosphor Adhesion between the body layer and the tubular glass substrate may deteriorate.

Such a tendency is particularly likely to occur when a transparent conductive oxide thin film is formed inside the tubular glass substrate and a phosphor layer is formed on this thin film. Therefore, when the tubular glass of the present invention is used as a fluorescent tube, it is preferable to apply a phosphor coating liquid after firing.

After forming a transparent conductive oxide thin film on the base material in this manner, a fluorescent tube can also be obtained by directly applying a phosphor coating liquid onto the transparent conductive oxide thin film.
In the present invention, it is preferable to further form a protective film on the transparent conductive oxide thin film formed by baking as described above.

That is, by forming a protective layer on the transparent conductive oxide thin film, the temporal stability and thermal stability of the transparent conductive oxide thin film can be further improved. In particular, when a transparent conductive oxide thin film is formed on the outer surface of a tubular glass substrate, it is preferable to form a protective film from the viewpoint of preventing scratches and electric shock to the human body.

Such a protective film can be formed using a coating solution for forming a protective film containing a hydrolyzate obtained by hydrolyzing silicon alkoxide, zirconium alkoxide, titanium alkoxide, etc. with an acid, a silicon chelate complex, a zirconium chelate complex, or a titanium chelate complex. It is obtained by coating the transparent conductive oxide thin film on the transparent conductive oxide thin film, followed by drying and baking. The thickness of the protective film is usually 0°0.
It is 1 to 0.2 μm.

In the thus obtained tubular lath with transparent conductive oxide of the present invention, the thickness of the transparent conductive oxide thin film is usually 0.01 to 2 μm. If the film thickness exceeds 2 μm, cracks are likely to occur in the thin film, and the resistance value of the thin film may become non-uniform. Furthermore, when applying the phosphor (powder), the adhesion of the phosphor tends to be poor.
The phosphor may peel off during the manufacturing process or during use of fluorescent lamps. Furthermore, the total light emission rate may be less than 80%, making it difficult to use such tubular glass for fluorescent lamps. On the other hand, if the film thickness is less than 0.01 μm, discontinuities may occur on the oxide coating surface on the tubular glass, and the conductivity of the thin film may be impaired.

Furthermore, in the present invention, the thickness of the transparent conductive oxide thin film is determined by taking into account the type of transparent conductive oxide, the surface resistance value of the thin film, the total light transmittance of the tubular glass with the transparent conductive oxide thin film, etc. , preferably within the range of 0.03 to 1 μm, particularly preferably within the range of 0.05 to 0.5 μm.

The surface resistance value of a transparent conductive oxide thin film having the film thickness as described above is usually within the range of 1KΩ/□ to 30MΩ/□. If this surface resistance value is larger than 30 MΩ/□, the amount of electricity accumulated during lighting will be small when using this tubular glass as a fluorescent lamp, and if it is smaller than IKΩ/□, the voltage required to start lighting will be reduced. Inconveniences may occur, such as not being able to obtain the desired results. Particularly in the present invention, it is preferable that the surface resistance value is within the range of 2Ω/Ω to IMΩ/□.

Further, in the present invention, the transparent conductive oxide thin film may be uniformly deposited on the surface of the tubular glass substrate, but the transparent conductive oxide thin film layer may have a sea-island structure or a somewhat porous structure. Preferably, it is formed and applied. Here, the sea-island structure refers to a structure consisting of a sea part made of oxide and an island part made of an exposed part of the surface of the tubular glass substrate, and the sea parts are seamlessly connected. Due to the formation of a sea-island structure, when a phosphor is coated on this thin film, the phosphor and its binder will penetrate into the transparent conductive oxide thin film, and may even penetrate into the tubular glass substrate. Since a thin film is formed through direct contact, the phosphor is difficult to peel off.

The glass with a transparent conductive oxide thin film of the present invention can be particularly suitably used as a fluorescent tube as described above, and can also be used, for example, as a cold cathode tube, a cover glass for a fluorescent display tube, and an electrostatic induction touch switch. It can also be used satisfactorily as a substrate glass.

Effects of the Invention In the tubular glass with a transparent conductive oxide thin film according to the present invention,
Since the conductive thin film is formed from an indium-tin composite oxide, it can be formed by a coating method without employing a vapor phase method as in conventional methods. Moreover, the conductive thin film formed in this way has a predetermined resistance value and thickness, and is also excellent in transparency, so tubular glass having this thin film is particularly useful for instant-lighting type fluorescent lamps. It can be suitably used as a tubular glass for.

Furthermore, by forming a protective film on the transparent conductive oxide thin film, it is possible to effectively prevent the transparent conductive thin film from peeling off.

EXAMPLES Next, the present invention will be explained in more detail by showing examples of the present invention, but the present invention is not limited to these examples.

Example 1 A solution containing an indium oxide-tin oxide precursor (ELCOM-YN-400, manufactured by Catalysts & Chemicals Industry Co., Ltd.) was poured into a tube with an inner diameter of 20 mm and a length of 1200 mm, one end of which was closed with a rubber stopper.
Pour about 100 cc into the glass tube for a fluorescent lamp, then close the other open end with a rubber stopper, place the glass tube horizontally, and roll it for about 1 minute until the solution spreads onto the inner surface of the glass tube. I tried to get the whole thing wet.

Then, the rubber plugs at both ends were removed to allow excess solution that did not adhere to the inner surface of the glass tube to flow out. Approximately 30 pieces of this glass tube
It was left inverted for a minute and excess solution was allowed to drain off. Next, the above-mentioned glass tube was placed in a drying mold set at a temperature of 200° C., and heat-treated for about 30 minutes to dry it.

Next, this glass tube was placed in a firing furnace whose temperature was set to 550°C, and heat treated for about 5 minutes. Through this operation, an indium oxide-tin oxide FiH having a thickness of 0.21 μm was formed on the inner surface of the glass tube.

When the electrical resistance of the thin film was measured, it was 420Ω,
When this was converted into a surface resistance value, it was 21.OMEGA./hole, and it was found that it had appropriate conductivity for use in an instantaneous lighting fluorescent lamp. In addition, the total light transmittance of this glass tube was measured using a haze computer (Suga Test Instruments ■) and the result was 87.
%Met.

Implementation! NJ2 A mixture of indium chloride and tin chloride is heated to about 800°C and fed in gaseous form with nitrogen gas as a carrier gas to thermally decompose it into a white fine powder of about 30%. I got it.

After repeatedly washing this fine powder with pure water, it was dispersed in acetone, the powder was collected by centrifugation, and the solvent was removed in a dry mold. The obtained fine powder was dispersed in ethanol using a homogenizer.

The slurry thus obtained was applied to the inner surface of a glass tube in the same manner as in Example 1, and dried at 200°C.

The coating film formed was an indium oxide-tin oxide thin film with a thickness of 0.33 μm.

When the electrical resistance of this thin film was measured, it was 740Ω. When this was converted into a surface resistance value, it was 37.OMEGA./mouth, and it was found that it had appropriate conductivity for use in an instantaneous lighting fluorescent lamp. Moreover, the total light transmittance was 86%.

Example 3 A reproducibility test of Example 1 was conducted. In exactly the same manner as in Example 1, indium-tin oxide was deposited on the inner surfaces of ten glass tubes for fluorescent lamps. The thickness and resistance of each thin film were measured.

The results are shown in Table 1. Note that the total light transmittance was 85% or more.

Table 1 As is clear from Table 1 above, the thickness and resistance value of the obtained tubular glass with a transparent conductive oxide thin film are both within the range of about ±10%, and by the method of the present invention, It has been found that it is possible to easily produce tubular glass with a transparent conductive oxide thin film with little variation. It should be noted that an instant lighting type wall light without any practical problems can be manufactured using tubular glass whose film thickness and resistance value variation range is within the ranges described above.

Comparative Example 1 Instead of the indium-tin oxide thin film, a tin-antimony oxide thin film was tried to be deposited, and a thin film physical property reproducibility test was conducted in the same manner as in Example 3.

Orgatics 5N-500 manufactured by Matsumoto Koshosha as a coating liquid
(oxide content 5%) was first placed in a quartz glass tube (inner diameter 20 mm).
The resistance at both ends was reduced to 45 Ω by applying it to the inner surface in a flowing manner and baking it in the same manner as in Example 1.
A tin-antimony oxide thin film was formed.

Next, five tubular glass tubes similar to those used in Example 1 were prepared, and a tin-antimony oxide thin film was formed on their inner surfaces in the same manner as in Example 1.

The results are shown in Table 2. The total light transmittance is 85% in both cases.
That was it.

Table 2 As is clear from Table 2, the resistance of tin-antimony oxide on alkali-containing glass, which is normally used as a fluorescent lamp tube, becomes significantly large, and the resistance value also varies widely. It was found that it could not be used as a glass tube for fluorescent lamps.

Example 4 A dilute solution was prepared by diluting the indium oxide-tin oxide precursor-containing solution (ELCOM-YN-400) described in Example 1 with an alcohol solvent, and using this dilute solution, the same procedure as in Example 1 was carried out. An indium oxide-tin oxide thin film was formed on the inner surface of the tubular glass. The resistance value was adjusted by the degree of dilution.

A fluorescent tube was then coated with a phosphor slurry and baked, and the initial starting voltage was measured at room temperature using a ballast.

The results are shown in Table 3. Note that the initial starting voltage (ballast input voltage) without such treatment was 80V.

Table 3

Claims (4)

[Claims] (1) A tubular glass with a transparent conductive oxide thin film comprising a tubular glass substrate and a conductive oxide thin film formed on at least a portion of the inner surface and/or outer surface of the substrate,
A tubular glass with a transparent conductive oxide thin film, characterized in that the transparent conductive oxide thin film is made of a composite of indium oxide and tin oxide. (2) The transparent conductive oxide thin film has a thickness of 0.01
~2μm range, and its surface resistance value is ~1KΩ/□
30 MΩ/□, and the total light transmittance of the tubular glass with a transparent conductive oxide thin film is 80% or more, according to claim 1. glass. (3) The tubular glass with a transparent conductive oxide thin film according to claim 1, wherein a transparent protective layer is provided on the transparent conductive oxide thin film. (4) When producing a tubular glass coated with a transparent conductive oxide thin film consisting of a tubular glass substrate and a conductive oxide thin film formed on at least a portion of the inner and/or outer surfaces of the substrate, A transparent conductive oxide characterized in that a coating solution for forming a transparent conductive oxide thin film containing a composite of indium oxide and tin oxide or a precursor thereof is applied to the substrate, and then dried and/or baked. A method for manufacturing tubular glass with a thin film.