KR840002447B1 - Electrode plane manufaction method for liquid crystal display - Google Patents

Abstract

A method for making electrode plate for liq. crystal display matter comprises (a) forming a liq. crystal aligning film, consisting of a material soluble to a basic soln. (e.g., polyimide or polyparabanic acid resin), on a base plate having electroconductive film; (b) forming a resist film, consisting of anti-basic resist ink (e.g., tar-epoxy system resin resist ink), in a desired form on the liq. crystal aligning film; (c) removing the liq. crystal aligning film from the part on which the resist film is not laminated by a basic etching liq. to regulate the liq. crystal aligning film into a desired form; and then (d) removing the resist film.

Description

Manufacturing method of electrode plate for liquid crystal display

The present invention broadly relates to a method for producing an electrode plate for a liquid crystal display. 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.

Background Art [0002] In recent years, liquid crystal displays using optical anisotropy of liquid crystal materials have become widely used as display parts for watches and various measuring devices.

The liquid crystal display is made of copper using the light scattering effect of the liquid crystal material obtained when an electric field is applied to a nematic liquid crystal material having negative dielectric anisotropy. ) Classified as field effect type (FE type) using the optical effect of the liquid crystal material obtained when an electric field is applied to a nematic liquid crystal material having a scattering type (DS type) and positive dielectric anisotropy. do.

Regardless of the DS type or the FE type, the liquid crystal display has a basic structure in which a liquid crystal material is sandwiched and sealed between a pair of electrode plates facing each other at a constant interval by a spacer. The electrode plate is made of a substrate, a conductive film (electrode) and a liquid crystal alignment film, and a liquid crystal alignment film is formed again on a substrate having a conductive film formed on its surface. Generally, a glass plate is used as a board | substrate.

As the material of the conductive film as the electrode, a conductive metal oxide such as indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), or a single metal such as aluminum or silver is used.

In general, the former gives a transparent light transmissive conductive film, while the latter gives an opaque light reflective conductive film. Each of the pair of electrode plates constituting the liquid crystal display is generally provided with a conductive film having a different shape, and the conductive film having a different shape is designed so that a conductive film including a desired display shape can be obtained when the pair of electrode plates overlap. . In addition, at least one conductive film (that is, at least the conductive film of the observation side electrode plate) of the pair of electrode plates constituting the liquid crystal display is a light transmissive conductive film.

The liquid crystal alignment layer of the electrode plate aligns the liquid crystal crystal material encapsulated in the liquid crystal display, orients the liquid crystal material when an electric field is applied between the electrode plates, so that the liquid crystal material exhibits a light scattering effect when an electric field is applied between the electrode plates. It is installed.

It is conventionally known that various inorganic materials such as silicon oxide or various organic materials such as polyimide resin, fluorine resin, polyvinyl alcohol resin, polyparabanic acid resin can be used as the material of the liquid crystal alignment film. The liquid crystal aligning film is formed to a thickness of 50 to 5000 kPa by the deposition method, the rotary coating method, the offset printing method, the spray coating method, or the like depending on the material used, and then the alignment treatment is performed on the surface to give liquid crystal alignment performance. .

The alignment treatment is performed by, for example, polishing the surface of the liquid crystal alignment film in a predetermined direction in a predetermined direction, but in general, when the alignment treatment is not performed, the liquid crystal alignment film has almost no liquid crystal alignment performance.

In addition, in the present specification, the term “liquid crystal alignment film” refers to a liquid crystal alignment film that is not subjected to the alignment treatment unless a clue is attached thereto.

As described above, the alignment film is indispensable for the liquid crystal display, but it is not necessarily provided on the entire surface of the electrode plate.

Rather, the liquid crystal alignment film is not provided in the peripheral portion of the electrode plate where the spacer is provided and the lead portion of the electrode (conductive film) exists in terms of adhesion between the spacer and the electrode plate and electrical connection between the electrode lead portion and the driving circuit. It is preferable.

Therefore, generally, a liquid crystal aligning film is generally formed on the front surface of a substrate having a conductive film, and then the liquid crystal aligning film is shaped before alignment processing to remove peripheral portions unnecessary for display.

Background Art A photoresist technique is conventionally used to shape a liquid crystal alignment film formed on the front surface of a substrate having a conductive film to remove unnecessary portions of the display. That is, in the conventional method in which negative photoresist technology is used, first, a photoresist ink made of a photocurable resin is applied and dried on a liquid crystal alignment film formed on the entire surface of a substrate having a conductive film to form a resist film. Next, a photomask having a light transmitting portion having a desired shape is positioned and placed on the resist film, and the resist film is exposed to light.

Post-exposure development is performed to leave the cured portion having a desired shape, and the resist film is removed from the uncured portion, and the liquid crystal alignment film of the portion is exposed. Thereafter, the exposed liquid crystal alignment film is removed by etching, and the residual resist film (cured portion) after etching is removed to obtain a liquid crystal alignment film having a desired shape.

In the conventional method in which a positive photoresist technique is used, a photodegradable resin is used instead of the photocurable resin, the resist film is exposed to a pattern opposite to the above, and the same operation as described above is performed next.

However, the conventional method using this photoresist technique has a complicated process, and therefore the electrode plate obtained has a high cost.

In addition, as a convenient method, the liquid crystal alignment film formed on one end plate is removed as in the conventional method described above, and thus the liquid crystal alignment film having a desired shape is not obtained by removing the unnecessary portion, but the offset printing method, spray coating method using a mask, etc. A method of directly forming a liquid crystal alignment film having a shape on a substrate has been attempted.

However, the liquid crystal alignment film obtained by this method tends to be uneven in film thickness, and it is difficult to accurately form the liquid crystal alignment film in a predetermined position, and thus the position of the liquid crystal alignment film is easily shifted.

When the film thickness of the liquid crystal alignment film is uneven, the alignment state of the liquid crystal material in the liquid crystal display obtained is deteriorated, and when the position of the liquid crystal alignment film is misaligned, the relative of the liquid crystal alignment film of the pair of electrode plates constituting the liquid crystal display film. Offset occurs and it is not preferable to the liquid crystal display in any case.

In the above situation, there is a demand for a method of manufacturing an electrode plate for a liquid crystal display which can be manufactured at low cost by simply following an electrode plate for a liquid crystal display in which a desired liquid crystal alignment film having a uniform film thickness is correctly installed at a predetermined position. have.

Accordingly, an object of the present method is to provide a method of manufacturing an electrode plate for a liquid crystal display, which can easily produce an electrode plate for a liquid crystal display with a desired liquid crystal alignment film having a uniform film thickness at a predetermined position. To provide.

MEANS TO SOLVE THE PROBLEM This inventor has made various research about the manufacturing method of the electrode plate for liquid crystal display bodies in order to achieve the said objective.

As a result, when a liquid crystal aligning film is formed using a material soluble in a basic solution on a substrate on which a conductive film is installed, and the liquid crystal aligning film is shaped using a resist technology using a resistive ink, the film thickness is uniform and the position of The present invention has been completed by discovering that an electrode plate having a liquid crystal alignment film having a desired shape without any deviation can be produced in a simpler manner than the conventional method using the photoresist technique.

The manufacturing method of the electrode plate for liquid crystal display of this invention is a manufacturing method of the electrode plate for liquid crystal display formed by forming a liquid crystal aligning film again on the board | substrate with which the conductive film was formed in the surface,

I) forming the liquid crystal alignment film made of a material soluble in a basic solution on the substrate having the conductive film formed thereon;

II) A resist film made of a base resistive ink is formed on the liquid crystal alignment film in a desired shape.

III) The liquid crystal aligning film is shaped into the desired shape by removing the liquid crystal aligning film in a portion where the resist film is not laminated by basic etching solution.

IV) The resist film is removed.

Resist technology is used in each aspect, but in most cases, an acid resistant resist ink is used as a resist ink, and this acid resistant resist ink is used in combination with a solution for acid.

Unlike such general resist technology, in the manufacturing method of the present invention, a resistive ink is used as a resist ink, and the resistive ink is used in combination with a quenching solution in basicity.

In the production method of the present invention, the base resist ink is mainly used for the following reasons.

I) The electrically conductive film which is an electrode generally has low resistance to acids.

II) Most of the materials used for the liquid crystal alignment film are basic degradable materials.

Next, the manufacturing method of this invention is demonstrated in detail.

In the manufacturing method of this invention, the board | substrate with which the conductive film was formed on the surface is prepared first. As described above, a glass plate is generally used as a substrate, and a conductive metal oxide such as In ₂ O ₃ , SnO ₂ , or a base metal having a basic resistance is used as a material of the conductive film.

A vapor deposition method, a sputtering method, etc. are used to form these electrically conductive materials and a thin film on a board | substrate, and to make a conductive film.

In general, a thin film of a conductive material is first formed on the front surface of a substrate, and then a thin film is shaped by photoresist technology or the like to remove unnecessary portions to form a conductive film of a desired shape.

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 on the surface.

Conventionally, various organic and inorganic materials suitable for the liquid crystal backing film are known, but any of those materials soluble in a basic solution can be used in the production method of the present invention. The material used for the liquid crystal alignment film needs to provide a film which can be provided with high liquid crystal alignment performance by the alignment treatment, but in addition to this, a film having high electrical insulation property and a film having high adhesion to the substrate on which the conductive film is formed are provided. I need to work.

At these three points, the liquid crystal alignment film materials which are soluble in the most basic solution at present are polyimide resins and polyparabanic acid resins.

Therefore, in the manufacturing method of this invention, it is preferable to use polyimide resin and polyparabanic acid resin as a material of a liquid crystal aligning film.

The liquid crystal alignment film is formed by a vapor deposition method, a rotary coating method, an offset printing method, a spray coating method, or the like depending on the material used.

In addition, a liquid crystal aligning film is generally formed in 50-5000 kPa film thickness.

After the liquid crystal alignment film made of a soluble material is formed in the basic solution, a resist film made of a base resistive ink is formed on the liquid crystal alignment film in a desired shape.

The basic resist ink needs to provide a resist film which is neither too high nor too low in adhesion with the liquid crystal alignment film.

This is because when the adhesion between the resist film and the liquid crystal alignment film is too high, it is difficult to remove the resist film from the crystal alignment film after etching, and when the adhesion between the resist film and the liquid crystal alignment film is too low, a splatter of the etching solution occurs during etching. Because it becomes easy.

Therefore, the resist ink is appropriately selected in consideration of the adhesion between the resist film formed by the ink and the liquid crystal alignment film.

As the base resist ink used in the production method of the present invention, for example, tar. Epoxy resin resist ink synthetic or natural rubber compound resist ink, polypropylene resin resist ink, polyethylene resin resist ink and the like.

As described above, the base resist ink is suitably selected in consideration of the adhesion between the resist film formed by the ink and the liquid crystal alignment film, but the base resist ink that is most suitable for the liquid crystal alignment film made of polyimide resin or polyparabanic acid resin is tar. . Epoxy resin resist ink.

This tar. Epoxy resin resist inks are commercially available from Yoshikawa Kakoo Co., Ltd. in Japan under the trade name Protook 340.

To form a resist film on the liquid crystal alignment film by using a basic resist ink, any method may be used as long as a resist film having a desired shape is formed at a predetermined position. However, in general, the resist film is preferably printed by screen printing. Do.

In general, a resist film is formed with a film thickness of 5 to 50 mu.

As described above, after a resist film having a desired shape made of a base resistive ink is formed on the liquid crystal alignment film, only the liquid crystal alignment film of the portion where the resist film is not laminated is etched away by the basic etching solution and the resist film is laminated. This remains on the substrate. This etching is performed by immersing the electrode plate provided with the resist film in basic etching liquid.

The etching conditions such as the etching time and the temperature of the etching liquid are precise, so these etching conditions must be strictly controlled so that good etching can be performed.

The basic etching solution is appropriately selected in consideration of the liquid crystal alignment film material.

For example, a basic etching solution suitable for a liquid crystal alignment film made of a polyimide resin may include an aqueous hydrazine solution and a basic degreasing agent (for example, Ogino Pharmaceutical Inc.), and a liquid crystal alignment film made of a polyparabanic acid resin. Examples of suitable basic etching solutions include ammonia water and the like.

After etching, the electrode plate is sufficiently washed with water and the basic etching solution is completely removed. Furthermore, when the resist film is made of synthetic or natural rubber compound resist ink, the washed electrode plate must be completely dehydrated.

This is a sulfonic acid compound in the release agent for exfoliating and removing a resist film made of a synthetic or natural rubber compound compound resist ink, but in the presence of water, the sulfonic acid compound is hydrolyzed to generate sulfuric acid, which is applied to the conductive film and the liquid crystal alignment film. Because it has a bad effect.

After etching with the basic etching solution described above, the resist film is removed.

Generally, this resist film is removed by immersing the electrode plate in the release agent or by spraying the release agent on the resist film. When removing a resist film by immersing an electrode plate in a peeling agent, it is preferable to provide 2 or more sets of peeling tanks, and to remove and remove a resist film, sending an electrode plate to these peeling tanks sequentially, in order to keep a liquid crystal aligning film clean.

In this case, it is preferable to use a ultrasonic wave to stir the release agent.

The release agent is suitably selected depending on the material of the resist film (ie, base resist ink).

Eg tar. Suitable release agents for the resist film made of an epoxy resin resist ink include halogenated hydrocarbon organic solvents such as bladder-based organic solvents such as xylene, tristyrene, and methylene chloride.

After removal of the resist film, the electrode plate is washed with a solvent such as alcohol and dried. In this way, an electrode plate having a liquid crystal alignment film shaped into a desired shape is obtained.

As is apparent from the above description, the manufacturing method of the present invention does not require the exposure and development steps necessary for the conventional method in which photoresist technology is used, and accordingly, the manufacturing method of the present invention is simpler and therefore lower cost than the conventional method. An electrode plate having a liquid crystal alignment film shaped into a desired shape can be obtained.

In addition, according to the manufacturing method of the present invention, it is possible to form a uniform liquid crystal alignment film as in the conventional method. Therefore, in the liquid crystal display body in which the electrode plate obtained by the manufacturing method of the present invention is used, the liquid crystal material exhibits a good alignment state.

In addition, according to the manufacturing method of the present invention, a liquid crystal alignment film having a desired shape can be accurately formed at a predetermined position as in the conventional method.

The deviation of the position of the liquid crystal aligning film of the electrode plate obtained by the manufacturing method of this invention is very small, and is usually within ± 0.1 mm.

As described above, the present invention can be produced at low cost by simply following the electrode plate for a liquid crystal display body in which a liquid crystal alignment film having a desired shape having a uniform film thickness is correctly installed at a predetermined position.

Incidentally, the present invention improves the quality of the liquid crystal display, makes the quality of the liquid crystal display uniform, and improves the production efficiency in manufacturing the liquid crystal display. Thus, the industrial use value of the present invention is very large.

Next, an Example demonstrates this invention.

Example 1

A glass substrate in which 20 glass substrates for 10 liquid crystal displays were integrated was prepared. On the surface of this glass substrate, a pair of conductive films (electrodes) having different shapes forming one liquid crystal display body are formed in two rows over the arc. A 1.5% dimethyl acetamide solution of polyamic acid, a precursor of polyimide, was applied onto the glass substrate by a rotary coating method, and the coating film was heated at 250 ° C. for 1 hour to polymerize and dry.

In this way, a liquid crystal alignment film made of polyimide resin was formed on the entire glass substrate.

Thereafter, using a screen made of 325 mesh stainless steel screen, tar was used to display the liquid crystal alignment film. Epoxy resin resist ink (Yoshika Chemical Co., Ltd. 340) was also printed and dried at 110 ° C for 10 minutes to form a resist film.

Subsequently, the glass substrate on which the resist film was formed was immersed for 1 minute while stirring in a 60% aqueous solution of hydrazine at 35 ° C to etch away the liquid crystal alignment film of the portion where the resist film was not laminated.

Immediately after etching, the substrate was washed with water to remove residual aqueous hydrazine solution. After sufficiently washing with water, the substrate was immersed in isopropyl alcohol to replace water, and then, the substrate was immersed in each of three sets of tricleene baths equipped with an ultrasonic stirrer for 3 minutes to remove and remove the resist.

Subsequently, the substrate was placed in an isopropyl alcohol steam bath, followed by steam washing and drying.

The glass substrate subjected to the liquid crystal alignment film shaping treatment as described above was polished in a predetermined direction to align the alignment and impart liquid crystal alignment performance to the liquid crystal alignment film.

Thereafter, the glass substrates were cut to obtain 20 electrode plates for 10 liquid crystal displays, and 10 liquid crystal displays were manufactured by the conventional method using these electrode plates.

In all of the obtained liquid crystal displays, the liquid crystal material showed the favorable orientation state. In addition, according to MIL Standard Test Method 202D-106C, even after 10 cycles of the temperature-humidity cycle test bar of each liquid crystal display, no abnormality was recognized in the liquid crystal display.

Example 2

An organic substrate similar to Example 1 was prepared.

On this glass substrate, a 3% dimethylformamide solution of polyparabanic acid resin was applied by a rotary coating method, and the coating film was heated at 200 ° C. for 30 minutes to dry. In this way, a liquid crystal alignment film made of polyparabanic acid resin was formed on the entire glass substrate.

Thereafter, screening plate using a mesh of 325 mesh stainless steel was used to tar the necessary portions for the display of the liquid crystal alignment film. Epoxy resin resist ink (Protook 340, manufactured by Yoshikawa Kakoo Co., Ltd.) was printed and dried at 110 ° C for 10 minutes to form a resist film.

Next, the glass substrate on which the resist film was formed was immersed for 2 minutes while stirring in 10% ammonia water at 35 ° C, and the liquid crystal alignment film of the portion where the resist film was not laminated was removed.

Immediately after etching, the substrate was washed with water to remove residual ammonia water.

After sufficiently washing with water, the substrate was immersed in isopropyl alcohol to replace water, and then, the substrate was peeled off for 3 minutes in each of three sets of triclenometers equipped with an ultrasonic stirrer. Subsequently, the substrate was placed in an isopropyl alcohol medium tank for steam washing and drying.

The glass substrate subjected to the liquid crystal alignment film shaping treatment as described above was polished in a predetermined direction to align the liquid substrate, thereby providing liquid crystal alignment performance to the liquid crystal alignment film.

Thereafter, the glass substrate was cut to obtain an electrode plate of 20 sheets for 10 liquid crystal displays, and 10 liquid crystal displays were manufactured by the conventional method using these electrode plates.

In all of the obtained liquid crystal displays, the liquid crystal material showed the favorable orientation state.

In addition, according to the MIL standard test method 202D-106C, each liquid crystal display was subjected to a temperature and humidity cycle test. After 10 cycles, no abnormality was found in the liquid crystal display.

Claims (1)

In the manufacturing method of the electrode plate for liquid crystal display formed by forming a liquid crystal aligning film again on the board | substrate with which the conductive film was formed in the surface, I) forming the liquid crystal alignment film made of a basic solution soluble material on the substrate having the conductive film formed on the surface thereof; II) A resist film made of base resist ink is formed on the liquid crystal alignment film in a desired shape, III) The liquid crystal aligning film is shaped into the desired shape by removing the liquid crystal aligning film in a portion where the resist film is not laminated by basic etching solution, and then, IV) The manufacturing method characterized by removing the resist film.