JPS58136017A - Manufacture of electrode plate for liquid-crystal display body - Google Patents

Abstract

PURPOSE:To provide a uniform-thickness oriented film in a desired shape at a prescribed position accurately and to realize cost reduction by using base-resisting resist ink consisting principally of asphalt. CONSTITUTION:On a glass substrate, a conductive film is formed in a desired shape and a material soluble in a basic solution such as polyimide resin or polyparabanic acid resin is used to form a liquid-crystal oriented film of 50-5,000Angstrom . Then, a resist film consisting of base-resisting resist ink is formed on said oriented film in a desired shape. The resist ink uses asphalt as a principal component and is mixed with a filler and a solvent. The resist film is formed by a screen printing method preferably to 5-50mum film thickness. After the oriented film is etched by a basic etching solution such as an aqueous hydrazine solution and aqueous ammonia, the resist film is removed. Then, the oriented film is rubbed.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to force law. More specifically, the present invention relates to a method for shaping a liquid crystal alignment film constituting an electrode plate for a liquid crystal display into a desired shape.

Recently, liquid crystal displays that utilize the optical anisotropy of liquid crystal materials have come into widespread use as display components for watches, various measuring devices, and the like. There are two types of liquid crystal displays: a dynamic scattering type (D'S type) that utilizes the light scattering effect of a nematic liquid crystal material that has negative dielectric anisotropy when an electric field is applied to the material, and a dynamic scattering type (D'S type) that utilizes the light scattering effect of a nematic liquid crystal material that has negative dielectric anisotropy. It is classified as a field-effect type (FE type) that utilizes the optical rotation effect of the liquid crystal Hamura obtained when an electric field is applied to a nematic liquid crystal material having a magnetic field.

Regardless of whether it is a Ds type or an FB type, a liquid crystal display consists of a pair of electrodes facing each other with a constant distance between them by a spacer. It has a basic structure in which the finished product Hamura is held between the I-tsuka and sealed. The electrode plate is a substrate, a conductive film (electrode), and a liquid crystal alignment film. − A liquid crystal alignment film is further formed on the top.

A glass plate is generally used as the substrate. As the material for the conductive film that is the electrode, conductive bonded oxides such as indium oxide (Z03) and tin oxide (SNO2)E, or deterrent metals such as aluminum and silver are used. Generally, the former is a transparent material. On the other hand, the latter provides an opaque light-reflecting conductive film.A pair of electrode plates constituting a liquid crystal display (generally JF-shaped different Z conductive films) The conductive films having different shapes are designed so that when a pair of electrode plates are overlapped, a superposition of conductive films including a desired display shape can be obtained. The conductive film on the lower tI side of a pair of electrode plates (
? 1'', that is, at least the conductive film on the observation side electrode plate) is a light-transmissive conductive film.

The HV component orientation film of the electrode plate is provided to orient the liquid crystal material sealed within the liquid crystal display so that the liquid crystal material exhibits a light scattering effect or an optical rotation effect when an electric field is applied between the electrode plates. It is. Various inorganic materials such as silicon oxide, polyimide resin, fluororesin, and polyvinyl alcohol resin are used as materials for liquid crystal alignment films. It is known in the art that various organic materials such as polyparabanic acid resins can be used. This liquid crystal alignment film is produced using a vapor deposition method depending on the side slope used. Spin coating method. Offset printing method.

5θ to S0θθA polishing by spray coating method or the like.

After that, the surface is subjected to alignment treatment to impart liquid crystal alignment performance. The alignment treatment is performed, for example, by polishing the surface of the liquid crystal alignment film in a certain direction.
Generally, when no alignment treatment is performed, a liquid crystal alignment film has almost no liquid crystal alignment performance. In addition, in this specification, when referring to "liquid crystal alignment film", unless otherwise specified,
It means a liquid crystal alignment film that has not been subjected to alignment treatment.

As mentioned above, the liquid crystal alignment film is essential to the liquid crystal display, or it does not necessarily need to be provided on the entire surface of the electrode plate, and at least 1! All you need to do is install a spacer on the part of the electrode plate that touches the LCD Hamura, or rather, a spacer. Haru (
The adhesiveness between the spacer and the electrode plate and the '#M. From the point of view of electrical connection with the polar reedley 1 partial circuit, it is ingenious that no liquid crystal alignment film is provided. Therefore, in general, a liquid crystal alignment film is first formed on the entire surface of a substrate having a conductive film, and before the re-deposition process, the liquid crystal alignment film is shaped and peripheral parts unnecessary for display are removed.

Conventionally, photoresist technology has been used to shape a liquid crystal alignment film formed over the entire surface of a substrate having a conductive film and to remove portions unnecessary for display. In other words, in the conventional method in which the Nekataive photoresist technology is used, a photoresist ink made of a photocurable resin is first applied onto several alignment films formed on the entire surface of a substrate having a conductive film, and then dried. A resist film is then formed. Next, a photomask having a desired shape (σ) and a light-transmitting portion is positioned on the resist film, and the resist film is exposed to light. After exposure, development is performed to remove the uncured portions of the resist I/film leaving the cured portions having the desired shape, thereby exposing the liquid crystal aligning film in those portions. Thereafter, the exposed liquid crystal alignment film is removed by etching, and the resist film remaining after etching is removed to obtain a liquid crystal alignment film having a desired shape. Furthermore, in the conventional method that uses positive photoresist technology, a photodegradable resin is used instead of the photocurable resin described above, the resist film is exposed to light in a pattern opposite to that described above, and subsequent operations similar to those described above are performed. will be carried out. However, the conventional method using this photoresist technology requires a complicated process, and the resulting electrode plate is therefore expensive.

In addition, as a simple method, as in the conventional method described above, a liquid crystal alignment film formed on a substrate is shaped and unnecessary parts are removed. Attempts have been made to form a liquid crystal alignment film with a desired shape directly on a substrate by offset printing, spray coating using a mask, etc.However, when using this method, the resultant liquid crystal alignment film The film thickness of the liquid crystal alignment film becomes non-uniform, and it is difficult to form the liquid crystal alignment film in a predetermined position.
Misalignment of V is likely to occur. If the thickness of the liquid crystal alignment film is uneven, the alignment state of the liquid crystal material in the liquid crystal display device deteriorates and the position of the liquid crystal alignment film becomes misaligned. The liquid crystal alignment films of the pair of electrode plates constituting the liquid crystal display are misaligned in two positions, which is not preferable since both of them are relative to the liquid crystal display 1.

Under the above-mentioned circumstances, it is difficult to provide a liquid crystal alignment film having a desired shape and a uniform film thickness at a predetermined location accurately9. For LCD display! Manufacture plates easily and therefore at low cost2)
There is a need for a method of manufacturing an IT plate for a crystal display that is capable of performing the following steps.

-X- Therefore, an object of the present invention is to easily provide an electrode plate for a liquid crystal display in which a liquid crystal alignment film having a desired shape and a uniform film thickness is accurately provided at a predetermined position.

Therefore, it is an object of the present invention to provide a method for manufacturing an electrode plate for a liquid crystal display that can be manufactured at low cost.

In order to achieve the above object, the present inventor has conducted various studies regarding methods of manufacturing electrode plates for liquid crystal displays. As a result, we formed a liquid crystal alignment film on a substrate provided with a conductive film using a material soluble in a basic solution, and used a base-resistant resist ink to form asphalt on this liquid crystal alignment film. When shaping using this technology, it is easier to create an electrode plate that has a uniform film thickness and a desired shape of the liquid crystal alignment film without misalignment than the conventional method that uses the above-mentioned photoresist technology. Therefore, it was discovered that it could be manufactured at a lower cost, and this led to the completion of the present invention.

The method for manufacturing an electrode plate for a liquid crystal display according to the present invention is for a liquid crystal display in which a liquid crystal alignment film is further formed on a substrate having a conductive film formed on the surface! In the method for manufacturing an electrode plate, 1) forming the liquid crystal alignment film Z made of a material soluble in a basic solution on the substrate having the conductive film formed thereon; 11) forming the liquid crystal alignment film on the substrate having the conductive film formed thereon; 111) By forming a resist film made of base-resistant lentic ink containing asphalt as a main component in a desired shape, and removing the liquid crystal alignment film in the portion where the resist film is not laminated using a basic etching solution. The liquid crystal alignment film is shaped into a desired shape, and then 1v) the resist film is removed.

The Renost technology is used in various fields, but in most cases, acid-resistant resist ink is used as the resist ink, and this 1T11 acid resist ink is used in combination with an acidic etching solution. Unlike such general resist technology, in the manufacturing method of the present invention, a base-resistant resist ink containing asphalt as a main component is used as the resist ink. Conductive films generally have low resistance to acids.

11) Most of the materials used for the liquid crystal alignment film 1 are base-decomposable materials.

The manufacturing method of the present invention will be explained in detail below.

In the manufacturing method of the present invention, a substrate having a conductive film formed on its surface is prepared. As explained earlier, general 1
A glass plate is used as the substrate, and a glass plate is used as the material for the conductive film.

A conductive metal oxide such as 5n02 is used. Vapor deposition, sputtering, or the like is used to form a thin film of these conductive materials on a substrate to form a conductive film.

In general, an IfI film of a conductive material is first formed on the entire surface of the substrate, and then a thin film is removed using photol/cyst technology.
[Conductive film 2 in the desired shape: Cut out.

Next, a liquid crystal alignment film made of a material soluble in a basic solution is formed on the substrate on which the conductive film is formed. Previously, MI! 1? Various organic and inorganic materials suitable for the alignment film are well known, and any of these materials that are soluble in a basic solution can be used in the manufacturing method of the present invention. The material used for the liquid crystal alignment film is a film that can be given high liquid crystal alignment performance by alignment treatment 1! It is necessary that σ),
In addition to providing a film with high electrical insulating properties, it also has high adhesion to the substrate on which the conductive film is formed.
1. What you can do with Ia is A. It is essential. these,
From the 7 points, the 11 products that are soluble in basicity MV at present are polyimide resins and polyparabanic acid resins. Therefore, in the manufacturing method of the present invention, it is particularly preferable to use polyimide resin and polyparabanic acid resin as materials for the liquid crystal alignment film.

The liquid crystal alignment film is formed by a vapor deposition method, a spin coating method, an offset printing method, or a spray coating method depending on the material used. The liquid crystal alignment film is generally SO~50θOA
It is formed with a film thickness of .

After a liquid crystal alignment film made of a material soluble in a basic solution is formed, a resist film made of a base-resistant resist ink is formed in a desired shape on this liquid crystal alignment film. The base-resistant resist ink has too high adhesion with the liquid crystal alignment film.
It is necessary to provide a resist film that is neither too thin nor too low. This is because if the adhesion between the resist film and the liquid crystal alignment film is too high, it will be difficult to remove the resist film from the liquid crystal alignment film after etching. This is because if it is too low, the etching solution tends to seep in during etching.

As a base-resistant resist ink used in the production method of the present invention that satisfies these conditions, asphalt is
to weight -15N, filler about 20~. ? S heavy jJ-X,
A resist ink whose main component is asphalt is used, which consists of a solvent of about 15 to qoX and a small amount of additives such as a flow agent, an antifoaming agent, and a thickener, if necessary. .

As the asphalt, straight asphalt with a penetration of θ to 300 specified in JIS K 2.20'l, blown asphalt with a penetration of θ to to, etc. can be used. degree 5-ro
blown asphalt is preferred.

There are no particular restrictions on the filler as long as it has good water resistance and base resistance, but representative examples include talc, mica, and precipitated barium sulfate 12 fathoms.In particular, scaly materials such as talc. is preferable because it prevents water permeation.

The solvent is not particularly limited as long as it does not dissolve the liquid crystal alignment film, but slow-drying solvents are suitable.

Any method can be used to form a resist film on a liquid crystal alignment film using such a base-resistant resist ink as long as a resist film of a desired shape is formed at a predetermined position. However, it is generally preferable that the resist film be applied by screen printing.

Further, the resist I/film is generally formed with a film thickness of S - Sθμ.

After a resist film of a desired shape made of base-resistant resist ink is formed on the liquid crystal alignment film as described above, the portions of the liquid crystal alignment film where the resist film is not laminated are etched away using a basic etching solution. The resist film is laminated.1. Only the crystal orientation film is left on the substrate 1- in the portion 1 where the crystal orientation film is located. This etching is carried out by immersing the electrode plate provided with the resist film in a basic etching solution.
Since the etching conditions (e.g., etching time, etching solution temperature) are critical, these etching conditions must be strictly controlled to ensure good etching.

The basic etching solution is for liquid crystal alignment film material →11t,
be selected as appropriate. For example, base-based etching liquids suitable for liquid crystal alignment films made of polyimide resin include hydrazine aqueous solutions, basic degreasing detergents (for example, Okuno Pharmaceutical Co., Ltd. trade name 1-A Clean), etc. Examples of basic etching solutions suitable for n+ crystal orientation films include ammonia water and the like.

After etching, the electrode plate is thoroughly washed with water to remove the basic etching solution.

After etching with the above-mentioned basic etching solution, the resist film is removed. Generally, this resist film is removed by immersing the electrode plate in a stripping agent or by spraying the resist film with a stripping agent. When removing a resist film by immersing an electrode plate in a stripper, two or more stripping tanks are provided, and the resist film is removed one by one while sequentially feeding the electrode plate into these stripping tanks. This is preferable in terms of keeping the alignment film surface clean. In this case, it is preferable to stir the release agent using ultrasonic waves.

Examples of the removal agent include aromatic organic solvents such as xylene, halogenated hydrocarbon organic solvents such as trichloride, and methylene chloride.

After removing the resist film, the electrode plate is cleaned with an alcohol-based solvent and dried. In this way, an electrode plate having a liquid crystal alignment film shaped into a desired shape ζ is obtained.

As is clear from the above description, the fR manufacturing method of the present invention requires exposure and development steps that are essential in conventional methods using photoresist technology. According to the method, it is possible to obtain an electrode plate supporting a liquid crystal alignment film shaped into a desired shape more easily and at lower cost than the conventional method. According to the manufacturing method of the present invention, a uniform liquid crystal alignment film can be formed in the same way as in the conventional method, and therefore, in a finished display body using the electrode plate obtained by the manufacturing method of the present invention, The liquid crystal material exhibits a good alignment state.

Furthermore, according to the manufacturing method of the present invention, a liquid crystal aligning film having a desired shape can be accurately formed in a predetermined position as in the conventional method. The positional deviation of the liquid crystal alignment film of the electrode plate obtained by the manufacturing method of the present invention is very small, and the normal soil Q, /
It is within 11m+.

As described above, the present invention enables easy and low-cost manufacturing of an electrode plate for a liquid crystal display in which a liquid crystal alignment film having a desired shape and a uniform film thickness is precisely provided at a predetermined position. AI
Incidentally, the present invention also improves the quality of the product indicator and improves the quality of the product label.
(m) To make the quality of the display body uniform and also to improve the yield rate in manufacturing the liquid crystal display body.

As described above, the industrial utility value of the present invention is extremely large.

Next, the present invention will be explained by examples.

Implementation example / The most crystalline display body lθ! A glass substrate in which 0 glass substrates were integrated was prepared. A pair of conductive films (electrodes) having different shapes constituting one liquid crystal display are formed alternately in a row on the surface of this glass substrate. A 75X dimethylacetamide solution of polyamic acid, which is a precursor of polyimide, was applied onto this glass substrate by a spin coating method, and the coating film was heated at -50°C for 7 hours to polymerize.
Dry.

In this way, a liquid crystal alignment film made of polyimide resin was formed on the entire surface of the glass substrate. after that,? , 2. Using a screen plate using a stainless steel filter mesh of 2K mesh, the areas necessary for displaying the liquid crystal alignment film were coated with 10-10 level of plane asphalt tIg% and Tashikuko 6x Ii%.

A resist ink consisting of Solbetsusona 15O (Etsuzo Standard f: J Oil Co., Ltd. trade name), 29 weight 1-X, and additive 2 weight 1% was applied by printing and dried at 710°C for 7 weight minutes to form a resist film. .

Next, remove the glass substrate on which the resist film was formed. The substrate was immersed in a 40% aqueous hydrazine solution of 40% hydrazine [gamma] for 7 minutes while stirring, and the liquid crystal alignment film in the portion where the resist film was not laminated was removed by etching. Immediately after etching, the substrate was washed with water to remove residual hydrazine aqueous solution. After thoroughly rinsing with water, the substrate was immersed in isopropyl alcohol to replace the water, and then the substrate was immersed for 3 minutes each in 3 tanks of Triclean testers equipped with an ultrasonic stirrer to peel off the resist layer. did. After that, the substrate was placed in an isopropyl alcohol vapor bath, and the O
,・1 Polishing the glass substrate, which has been subjected to the liquid crystal alignment film shaping process as described above, in a certain direction1.Thus, the alignment film f! I! L
, , imparted liquid crystal alignment performance to the lIt crystal alignment film.

After that, the glass substrate was cut to obtain 20 electrode plates for 70 liquid crystal displays, and 70 electrode plates were obtained using a stiff electrode plate in the usual manner.
In all of the liquid crystal displays obtained by manufacturing 4-o liquid crystal displays, the liquid crystal Hamura exhibited a good alignment state. Further, when each liquid crystal display was subjected to a temperature/humidity cycle test according to MIL standard test method 20coD-/θ6C, no abnormality was observed in the liquid crystal display even after the IO cycle had passed.

Example λ The same glass substrate as in Example 1 was prepared. A solution of polyparabanic acid resin in 396 dimethylformamide was applied onto this glass substrate by a spin coating method, and the coating film was applied at θO℃ for 3
It was heated and dried for 0 minutes. In this way, a liquid crystal alignment film made of polyparabanic acid resin was formed on the entire surface of the glass substrate. after that,,? Using a screen plate using a 25-mesh stainless steel mesh, the resist ink containing asphalt as the main component used in Example 20-1 was printed and coated on the areas necessary for displaying the liquid crystal alignment film. A resist film was formed by drying at ℃ for 7 minutes.

Next, the glass substrate on which the resist film was formed was heated to 10°C at Js°C.
% ammonia water for 2 minutes with stirring, and the portions where the resist film was not laminated were etched away.

Immediately after etching, the substrate was washed with water to remove residual ammonia water. After thoroughly rinsing with water, the substrate was immersed in inpropyl alcohol to replace the water, and then the substrate was immersed for 3 minutes each in 3 tanks of Triclean testers equipped with ultrasonic stirrers to form a resist layer 8@ Removed. Thereafter, the substrate was placed in an isopropyl alcohol vapor bath for steam cleaning and drying.

The glass substrate subjected to the liquid crystal alignment film shaping treatment as described above was subjected to alignment treatment by polishing in a certain direction, thereby imparting liquid crystal alignment performance to the liquid crystal alignment film. After that, the glass substrate was cut to obtain 10 electrode plates minus 0 electrode plates for 10 liquid crystal displays, and these 1! Seventy liquid crystal displays were manufactured using the electrode plates in a conventional manner. In all of the obtained liquid crystal display bodies, the liquid crystal layer showed a good alignment state. When each liquid crystal display was subjected to a temperature/humidity cycle test in accordance with MIL Standard Test Method 202D-tOC, no abnormality was observed in the liquid crystal display even after 10 cycles had passed.

Applicant: Dainippon Toyo Co., Ltd. −+2.3 −

Claims (1)

[Claims] (1) On a substrate with a conductive film formed on the surface? Furthermore, in the method for producing an electrode plate for a liquid crystal display by forming a liquid crystal alignment film, the liquid crystal alignment film made of a material soluble in a basic solution is formed on the substrate on which the conductive film is formed. 11) forming a resist film made of a base-resistant resist ink containing asphalt as a main component on this liquid crystal alignment film in a desired shape; The liquid crystal alignment film is shaped into the desired shape I by removing the liquid crystal alignment film of
A manufacturing method characterized in that the resist film is shaped, and then 1v) the resist film is removed. (,/) Manufacturing capacity θ according to range 1m of the special Pf bamboo claim, characterized in that it is a material soluble in the above-mentioned basic material or polyimide resin. (3) The above-mentioned basic solution-soluble 161-gold tree I is characterized in that it is polyparabanic acid grains).
R+? I! ! nI′ljJ method. (4'l) The first range of special Y [requested] R characterized in that the above-mentioned resist film is formed by a screen printing method (2).
Nachino + No. 1? (5) A patent characterized in that the film thickness of the above-mentioned Tosost film is 50μ.
The manufacturing method described in any of the sections. (6) The thickness of the liquid crystal alignment film is 50 mm; 0OO
It's A! A manufacturing method according to the Isuwaka section of Claims 1 and 2, characterized in that: