JPH0147414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrode glass plate in which an oxide film of an In-Sn metal is formed as a transparent electrode on a glass substrate.

Electrode glass substrates are widely used in electro-optical devices such as various display devices using liquid crystals, EL, plasma, etc.

For example, a liquid crystal display device is constructed by using two glass substrates and filling a gap between these glass substrates with a liquid crystal composition. Electrodes are formed on the surfaces of the glass substrates holding the liquid crystal composition in a shape corresponding to the display content in order to apply an electric field to the liquid crystal composition. The electrode is formed of a transparent electrode at least on the side on which the display is viewed, and usually an In--Sn metal oxide film (hereinafter referred to as ITO film) is used.

The ITO film shown above is first coated with In− on the glass plate surface.
Sn-based metal is deposited, and this deposited film is oxidized by firing to form a transparent conductive film.

By the way, when manufacturing a glass plate with the above-mentioned ITO film, if the glass plate surface is not kept in a clean state, when the liquid crystal composition is held, the quality of the liquid crystal may change or defects may appear in the display. There is a risk of causing inconveniences such as Therefore, cleaning of the glass plate is performed at an appropriate stage of the manufacturing process. Conventionally, high-temperature heating has been widely used for cleaning glass substrates. Such high-temperature heating is effective in removing moisture and oil. But as mentioned above, In
−When cleaning a glass plate on which Sn metal is vapor-deposited,
The In-Sn metal film is oxidized by exposure to a high-temperature heating atmosphere, and the film, which was black in the metallic state, changes to a transparent film due to the oxidation. The state of the transparent membrane is
Although it does not cause any problems as a glass plate for the finished liquid crystal display device, it has the disadvantage that it makes the work much more difficult when patterning the metal film into a shape that corresponds to the display content, compared to a black metal film. It was hot.

The present invention was made in view of the drawbacks in the above-mentioned conventional method for manufacturing a glass plate equipped with an ITO film.
The object of the present invention is to provide a method for manufacturing an electrode glass plate that suppresses the black In-Sn metal film from becoming transparent due to cleaning and ensures ease of electrode patterning.

That is, in the present invention, a glass plate on which an In-Sn metal film is deposited is exposed to ultraviolet light to be cleaned. Ultraviolet light has the effect of removing dust, moisture, etc. adhering to the surface of the glass plate. On the other hand, the temperature rise on the irradiated glass plate surface can be suppressed to about 130°C, and the
- It is possible to prevent the Sn metal film from becoming transparent due to firing. Also, the time required for cleaning is approximately 60 minutes under a mercury lamp.
A sufficient effect can be obtained with extremely short ultraviolet irradiation of about 240 seconds.

FIG. 1 shows an apparatus for irradiating ultraviolet light onto a glass plate 1 on which an In-Sn metal film has been deposited. It is provided. A high-pressure mercury lamp 4 is installed as an ultraviolet light source in a space surrounded by the condensing reflector 3. The ultraviolet rays emitted from the mercury lamp 4 are directed toward the glass plate 1 either directly or reflected by the reflection plate 3, and quickly clean the glass plate 1 provided with the In-Sn metal film. As shown in FIG. 3, the glass plate 1 carried by the conveyor 2 is cleaned by the ultraviolet rays 4 condensed in a line from one end to the other.

Figure 4 shows a mercury lamp (HO151) manufactured by Eye graphics, which was adopted as the mercury lamp 4 used in this example.
-L312) wavelength spectrum. The light source intensity of the mercury lamp is 15W. FIG. 5 is a graph showing the correlation between the ultraviolet irradiation time and the contact angle of liquid crystal molecules on the glass plate surface. As the irradiation time increases, the contact angle of liquid crystal molecules gradually decreases. This means that the activity of the glass plate surface becomes smaller.

When ultraviolet rays are irradiated onto a glass plate surface with dust attached, if the irradiation energy of the ultraviolet rays is greater than the intermolecular bonding energy of the organic compounds that make up the dust, the organic compounds are decomposed and the oxygen in the air becomes ozone. After the chemical reaction, decomposition into radical oxygen is caused, and molecules are formed by reaction with organic substances in an excited state, which are then removed from the glass plate surface. Further, moisture adhering to the glass plate surface is evaporated and removed by ultraviolet irradiation. As described above, the surface of the glass plate is cleaned using ultraviolet irradiation. This is known as the ultraviolet cleaning effect.

During the cleaning process, the lit mercury lamp 4 generates heat at the same time, so the space surrounded by the reflector plate 3 is used to cool the mercury lamp 4 and to remove ozone, which is generated by the emitted ultraviolet rays. An exhaust hole 5 is provided to communicate the air to the outside, and an exhaust fan 6 is attached as shown in FIGS. 2a and 2b, which will be described next.

FIGS. 2a and 2b are a side view and a front view showing the overall appearance of the cleaning device equipped with the ultraviolet irradiation section, in which the ultraviolet irradiation section shown in FIG. 1 is housed within the outer cover 7.

Since the glass plate cleaned by ultraviolet irradiation is not exposed to high temperatures, the In-Sn film is preserved as a metal film, and therefore has a black color.
Next, the In--Sn metal film is patterned into a shape corresponding to the electrode pattern by a conventionally known etching process, and after pattern etching, it is fired at a high temperature to oxidize the metal layer and become an ITO transparent conductive film. The glass plate provided with the above-mentioned ITO film can be used not only for liquid crystal display devices but also as an electrode substrate for EDCs and the like.

As explained in detail above, the present invention makes it possible to clean the surface of a glass plate on which an In-Sn metal film is formed using ultraviolet light, thereby making it possible to clean the surface at a low temperature. can be maintained in this state. Furthermore, since the metal film is black, it is easy to observe and the subsequent electrode patterning work is significantly facilitated.

[Brief explanation of drawings]

Fig. 1 is an enlarged view of the main parts of a cleaning device for carrying out the present invention, Figs. 2a and b are a side view and a plan view of the same cleaning device, Fig. 3 is a view showing the ultraviolet irradiation state, and Fig. 4 is a spectrum diagram of a mercury lamp, and FIG. 5 is a graph showing the correlation between the ultraviolet irradiation time and the contact angle of liquid crystal molecules on the glass plate surface. 1: Glass plate, 4: Mercury lamp.

Claims (1)

[Claims] 1 After depositing an In-Sn metal film on the glass plate surface,
A method for producing an electrode glass plate, which comprises exposing the glass plate to ultraviolet light to decompose organic deposits on the surface of the glass plate and cleaning the surface.