JPH0130130B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a field effect liquid crystal display panel applied to the display section of a portable watch, and more particularly to a method for manufacturing a liquid crystal display panel having a horizontal alignment treatment agent for nematic liquid crystal. Various methods have been proposed for field-effect display panels using nematic liquid crystals, but the most practical method is one in which the long axes of liquid crystal molecules are aligned with the long axes of the liquid crystal molecules on two transparent substrates. By aligning the liquid crystal layer parallel to the surface and in a fixed direction, and shifting the alignment direction of the two substrates by 80° to 90°, we have created a structure in which the alignment direction of the liquid crystal layer between the substrates is continuously twisted. This is a display device (abbreviated as TN type display) that uses a liquid crystal cell. Since this method can be driven at a low voltage (2 to 5 volts AC), it can be operated with a single small battery and consumes little power (approximately 10 ^-6 W/cm ² ) for continuous display. It has been put into practical use in wristwatches, industrial instruments, small calculators, etc. However, the so-called horizontal alignment process of this method, in which the long axes of liquid crystals are aligned parallel to the substrate surface and in a fixed direction, has not yet reached the point where long-term quality is sufficiently satisfied. Traditionally, horizontal alignment processing for TN display panels involves forming a single layer film of a substance that is compatible with both the transparent substrate (e.g., glass substrate) and the liquid crystal, and then rubbing it in a certain direction (hereinafter referred to as "rubbing") to achieve a uniform coating. Obtaining the molecular sequence. As compatible substances, for example, those shown in Table 1 were effective as surface treatment agents for glass. Additionally, SiO was obliquely deposited using vacuum evaporation to obtain a uniform molecular arrangement. but,
In the former surface treatment agent + rubbing treatment, it was difficult to obtain a stable horizontal alignment treatment due to strict treatment conditions. In particular, since it is greatly affected by the temperature and humidity of the processing atmosphere, great care was required when handling it. Furthermore, there are major restrictions on the quality of rubbing materials. Also, theoretically, it has not yet been fully elucidated. In addition, the surface treatment agents listed in Table 1 decompose in the range of 150 to 200℃, so
We have not reached the point where we can sufficiently ensure long-term quality. Even in accelerated panel deterioration tests at high temperatures (for example, 110°C), the average lifespan was 150 to 200 hours. Furthermore, the latter orientation treatment by oblique evaporation of SiO has the disadvantage of lacking in productivity due to batch treatment. Further, since the treatment is impossible when the substrate becomes large, or because SiO itself is physically unstable, this treatment has not been able to sufficiently ensure long-term quality.

[Table] The present invention provides a horizontal alignment process that satisfies maximum productivity and long-term quality while eliminating the above-mentioned drawbacks. The present invention will be described in detail below, including examples. Organosilicon with four hydrolyzable groups, general formula = Si(OR) ₄ , is hydrolyzed to form Si(OH) ₄ , which becomes stable when dissolved in alcohol-based, ester-based, and fluorine-based solvents. exist. The solution is applied onto a glass substrate having a transparent electrode and dried with a solvent to form a silicon hydrolyzed film. By rubbing the film with absorbent cotton or the like to form grooves of several Å to several tens of Å in a certain direction, and firing at 500 to 550°C,
Make it a SiO ₂ film. However, in this method, the film on the transparent electrode is destroyed during firing due to poor adhesion or a difference in coefficient of thermal expansion. Therefore, the alignment of liquid crystal molecules on the transparent electrode is not controlled at all. Therefore, in the organic silicon treatment solution,
General formula Me(OR) ₄ (where Me is Ti, Ce, or Sn)
By adding a hydrolyzable organic metal represented by the formula, an SiO ₂ film with excellent adhesion and not being destroyed during firing can be obtained by forming an SiO 2 film on a glass substrate with a transparent electrode. I found out. The effect will be explained in detail below. Generally, when hydrolyzing Si(OR) ₄ , it is usual to accelerate the hydrolysis by adding an acid or base, or by forcibly applying heat. In contrast, in the present invention, a hydrolyzable organic metal, specifically Ti(OR) ₄ or Ce
By combining (OR) ₄ or Sn(OR) ₄ , Ti,
Although Ce and Sn ions are present, they do not inhibit the hydrolysis of organic silicon. Therefore, in a mixed solution of organosilicon and the above-mentioned organometallic, Si(OR) ₄ is hydrolyzed to form Si.
(OH) ₄ is formed. Then, this solution is applied onto a glass substrate, and the OH groups of Si(OH) ₄ are uniformly and densely bonded to the transparent electrode and the glass substrate on the entire applied surface, so this solution is heat-treated. However, the adhesion between the transparent electrode and the glass substrate and the hydrolysis product was not impaired in any way, and still had excellent adhesion. Furthermore, since no acid or base is used during hydrolysis, there is a synergistic effect in that the transparent electrode and glass substrate are not damaged at all. Furthermore, the presence of metal oxides of Ti, Ce, and Sn in SiO ₂ makes the crystals denser, resulting in a hard and strong coating. Example 1 Tetramethoxysilane {Si(OCH ₃ ) ₄ } is dissolved at 10% in methanol, and 3% tetraoctyl titanium {Ti(OC ₃ H ₁₇ ) ₄ } is added. The solution is applied onto a glass plate on which transparent electrodes are formed. As a coating method, coating treatments such as a spinner method, a dipping constant velocity pulling method, a spraying method, and a roll coater are possible. Dry the coated glass plate thoroughly in a constant temperature bath at 120°C to 150°C. Then rub several times with cotton wool
Then, it was further baked at 500°C for 30 minutes. When the treated glass was made into cells using Epoquine adhesive or low melting point glass and liquid crystal was injected, sufficient alignment control was confirmed even on transparent electrodes. Furthermore, 110℃
Even in the accelerated panel deterioration test, superior adhesion was obtained compared to conventional products. Example 2 Tetraethoxysilane {Si(OC ₂ H ₅ ) ₄ } is dissolved in ethanol at 13%, and tetrabutoxycerium {Ce(OC ₄ H ₉ ) ₄ } is added at 1.5%. The solution is applied onto a glass plate on which transparent electrodes are formed. Dry the coated glass plate thoroughly in a constant temperature bath at 120°C to 150°C. Next, rub it several times with absorbent cotton and heat it to 500℃.
Bake for 30 minutes. When the treated glass was made into cells using an epoxy adhesive or low melting point glass and liquid crystal was injected, sufficient alignment control was confirmed even on transparent electrodes. Furthermore, in an accelerated panel deterioration test at 110°C, superior adhesion was obtained compared to conventional products. Example 3 Tetrabutoxysilane {Si(OC ₄ H ₉ ) ₄ } is dissolved at 15% in isopropyl alcohol, and 5% tetrabutoxytin {Sn(OC ₄ H ₉ ) ₄ } is added. The solution is applied onto a glass plate on which transparent electrodes are formed. Dry the coated glass plate thoroughly in a constant temperature bath at 120°C to 150°C. Next, rub it several times with absorbent cotton, and then
It was baked at 550°C for 30 minutes. When the treated glass was made into cells using an Epoquine adhesive or low melting point glass and liquid crystal was injected, sufficient alignment control was confirmed even on transparent electrodes. Furthermore, in an accelerated panel deterioration test at 110°C, superior adhesion was obtained compared to conventional products. As described above, according to the present invention, Si(OH) ₄ and Me
(OR) ₄ (where Me represents Ti, Ce, and Sn) is applied onto a glass substrate with a transparent electrode, and then dried or baked as specified.
It works in conjunction with Me(OR) ₄ to generate Si(OH) ₄ in the mixed solution, and as this is extremely tightly bound to the transparent electrode and glass, it is extremely difficult to dry and sinter it. Has excellent adhesion. Furthermore, since the metal oxide films of Ti, Ce, and Sn are contained in SiO ₂ , the crystals become dense, making it possible to form a hard and strong film. In addition, the reason why the film is dried at 120°C to 150°C before the rubbing process is that the film formed in this temperature range is soft and the rubbing process allows the alignment grooves that align the liquid crystal molecules to be formed evenly and uniformly.
By heating at 500 to 550°C, the film is completely vitrified, so that an alignment film in which the grooves are extremely stable can be obtained.

Claims (1)

[Claims] 1. Organosilicon Si having four hydrolyzable groups
(OR) ₄ [However, Si is silicon element, O is oxygen element,
R is an alkyl group] and the general formula Me(OR) ₄ [however
Me is Ti, Ce, or Sn, O is an oxygen element, and R is an alkyl group] A solution mixture of hydrolyzable organometallics represented by
Coated on a glass substrate with transparent electrodes, 120
1. A method for manufacturing a liquid crystal panel, which comprises drying at a temperature of 150 degrees Celsius to 150 degrees Celsius, rubbing the surface thereof, and then heating and baking the panel at 500 degrees Celsius to 550 degrees Celsius to make it inorganic.