JPS59184325A - Production of multicolor liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain an element formed with a protective layer which prevents elution of the components in a color filter layer into a liquid crystal by coating a specific aq. soln. added with a photosensitive agent on the substrate surface on which an electrode and the color filter layer are formed and drying the coating then exposing the image of a required pattern and developing the image. CONSTITUTION:An aq. PVA soln. added with a photosensitive agent is coated by a spinner on a transparent electrode 2 and the upper layer of a color filter layer 3 formed on the surface of a glass substrate to form a PVA film. The film 4 is then irradiated with UV light through a pattern mask 6 having a required shape to photocure the PVA film 5 in the exposed region. Cold water kept at about 10 deg.C or ordinary temp. water added with about 0.5% acetic acid by weight is sprayed on the substrate surface to develop the same while the substrate mounted on the spinner upon ending of the exposure is kept rotated, then the PVA film in the unexposed region is removed and only the region of the electrode and color filter layer is coated with the cured PVA layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a multicolor liquid crystal display element, and in particular,
A protective layer that prevents the components of the color filter layer formed on the electrode surface for multicolor display from eluting into the liquid crystal.
This invention relates to a method of forming only in required areas.

Regarding the multicolor liquid crystal display element that is the subject of the present invention, the present inventors have already applied for a patent as Japanese Patent Application No. 1987-201987 (title of the invention ``Method for manufacturing multicolor image display device''). ing. In order to understand the present invention, an outline of the invention of this prior application will be explained.

As shown in FIGS. 1 and 2, a pair of substrates (21) are arranged parallel to each other, and a large number of fine electrodes (22) are formed on each of the opposing surfaces, and one of these electrodes (22) , a color filter layer consisting of three primary colors of light: red (R), green (G), and blue (B). The gap created by the pair of parallel substrates (21) is filled with liquid crystal (24), and its periphery is sealed with a sealing material (25) that also functions as a spacer. . Also,
The multicolor image display section consists of a large number of minute areas (11) corresponding to so-called pixels of the original image, and each minute area (11) has three colors: red (R), green (G), and blue (B). It has a color filter layer.

In the multicolor liquid crystal display element configured in this way, each electrode (22) on which a color filter layer is formed and the liquid crystal (22)
When a predetermined voltage is applied between the liquid crystal (24) and the opposing electrode (22) via the liquid crystal (24), the amount of transmitted light or reflected light of the liquid crystal (24) is controlled.
1) Displayed on top.

In addition, in such a multicolor liquid crystal display element, an electrode (22) and a color filter layer (23) are formed as shown in the third figure in order to prevent components contained in the color filter layer from eluting into the liquid crystal. It is also described in the specification of the above-mentioned earlier application that the surface of the substrate (21) that has been coated is coated with a protective layer (26), and that the protective layer (26) is provided with an alignment function necessary for a liquid crystal display element. There is. Furthermore, several types of organic polymer substances are listed as materials constituting the protective layer, which are coated with a spinner to form a layer with a thickness of about 0.1 μm or less, and rubbed to produce an orientation function. It is also disclosed that.

By the way, according to experiments conducted by the present inventors, some of the above-mentioned organic polymer substances, when used as a protective layer/alignment film in the above-mentioned multicolor liquid crystal display element,
It turns out that a problem exists. In other words, when some substances are applied, the dye in the color filter layer dissolves into the substance itself, causing the color display function to deteriorate;
Although the dye does not elute, if it is heated during the fixation of the sealing material in the subsequent process, the writing function is almost lost, making it unusable.

According to research conducted by the present inventors, it has been found that the above object can be achieved by applying polyvinyl alcohol (hereinafter referred to as PVA) under specific conditions. That is, P
If the VA aqueous solution is used at room temperature, the dye in the color filter layer will elute, but if it is applied after cooling to 20°C or below, preferably about 10°C, dye dissolution can be almost completely suppressed. Furthermore, a PVA film subjected to a rubbing treatment after drying maintains its alignment function even after the heating process, making it suitable as a protective layer and alignment film in multicolor liquid crystal display elements. I got something.

The above means is an outline of an invention that was filed for a patent (invention title: "Multicolor liquid crystal display element and method for manufacturing the same") by the applicant of the present application on March 16, 1982, separately from the present case. The present invention relates to a method for forming a polymerized PVA film with strong film quality only in a required area on the substrate surface of a display element, using the protective layer/alignment film formed based on the method of the invention of this prior application.

In other words, in a multicolor liquid crystal display element, the display electrode portion on which the color filter layer is laminated is required to be covered with a protective layer/alignment film as described above, but it is necessary to cover the display electrode portion with a protective layer/alignment film as described above. It is inconvenient for the connection terminals, etc. of the Selective removal is necessary.

Screen printing is a widely used method for selectively applying a PVA aqueous solution to the required areas, but this method results in an excessively thick film and is difficult to obtain a uniform film thickness. Since it is difficult to use, it is not suitable as a means for forming a protective layer and an alignment film for a multicolor liquid crystal display element, which is the object of the present invention.

In addition, although spin coating and dipping methods can satisfy the requirements for film thickness and uniformity, they cannot be applied selectively, so the required area must be covered with a removable resin, masking tape, etc. prior to application. In any case, delicate manual work is required, and the PVA film of the exact shape must be washed out with a solvent such as water after application. It has the disadvantage that it is difficult to form a film.

In order to solve the above-mentioned problems, the present invention provides a method that can accurately remove a PVA film in a required area based on a photographic technique.

Generally, it is well known that photoprinting means, so-called photolithography, is commonly used to form a PVA film in a desired shape on the surface of a substrate. That is, a photosensitizer is added to a PVA aqueous solution and applied, and after drying, a required pattern of fog light is applied and development is performed to form a PVA group corresponding to the exposed pattern.As an added photosensitizer, , dichromate-based photosensitizers, diazo resin-based photosensitizers, diazonium salt-based photosensitizers, azide compound-based photosensitizers, etc., but in addition to these, they can also be added to PVA to absorb light energy upon exposure. Any material may be used as long as it has the property of causing a cross-linking reaction between PVA molecules to form water-insoluble PVA.

In the method of the present invention, even when the above photosensitizer is added to the PVA aqueous solution, there is no effect on the function of the formed PVA film as a protective layer and alignment film; rather, when the PVA aqueous solution is simply dried and cured. It has been experimentally confirmed that the strength of the film is increased and the durability of the film is improved. But the problem is that PVA
It is a development process after exposing the film.

That is, in general photolithography, water is used to develop a PVA photosensitive film, but in the case of the multicolor liquid crystal display element of the present invention, when developed with room temperature water according to a general method, The dye in the color filter layer is eluted into the developing water,
This will cause the color filter to fade. This is because the PVA film covering the color filter layer swells when it comes into contact with water even after it becomes insoluble through photocuring, and cannot completely block the infiltration of developing water. Conceivable.

As a result of experiments, it was found that this problem could be solved by using cold water as a treatment during the development process, or by adding an appropriate amount of an organic acid such as acetic acid (CH3COOH) to room temperature water.

In either case, almost no dye elution from the color filter layer is observed during the development process, and the process is extremely effective.

When cold water is used, a temperature of about 10°C is most appropriate, but a temperature of 20°C or less has the effect of suppressing dye elution.

In addition, when adding an organic acid, the weight ratio is about 0 to room temperature water.
．． By adding 5% organic acid, dye elution could be suppressed. Even if the amount of organic acid added is changed over a fairly large range, there is no noticeable change in this suppressing effect, and it is from 0.01% to 0.01%.
Although it can be used in a range of about 5%, a value around the above-mentioned about 0.5% is practically optimum.

4 to 6 are schematic diagrams showing the steps of carrying out the method of the present invention.

Figure 4 shows a transparent electrode (
2) and the upper layer of the color filter layer (3), a PVA aqueous solution containing a photosensitizer is applied using a spinner, and the PV
The state in which the A film (4) is formed is shown.

FIG. 5 shows that the PVA film (4) is irradiated with ultraviolet light through a pattern mask (6) of a desired shape, and the PVA film (4) in the exposed area is
A state in which the VA film (5) is photocured is shown. Needless to say, the pattern mask (6) is a film or the like which is blackened in a shape corresponding to the area so as to block light from the area where the PVA film is to be removed after development.

Also, in Figure 5, for understanding, pattern mask (6)
is shown at a distance from the PVA film surface, but the "burning blur"
In order to prevent this, it is desirable to use a vacuum printer or the like to make them adhere closely.

After completing the exposure, while the substrate was mounted on a spinner and rotated, cold water at about 10° C. or room temperature water to which acetic acid was added at a weight ratio of about 0.5% was sprayed onto the substrate surface as described above. When the development process is performed, the PVA film in the unexposed area is removed, and a substrate can be obtained in which only the electrode and color filter layer areas are covered with the cured PVA film and the connection terminals are exposed, as shown in Figure 6. and during the development process,
The inconvenience of the dye in the color filter layer being eluted into the developing water can be avoided.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view showing the structure of a multicolor liquid crystal display element, which is a target of the method of the present invention, Fig. 2 is a side sectional view of the same, and Fig. 3 shows a state in which a protective layer/alignment film has been applied. FIG. FIGS. 4 to 6 are schematic diagrams showing the steps of the method of the present invention.

Claims (5)

[Claims] (1) A liquid crystal is filled between the facing substrates, and the liquid crystal is filled with an electrode of a desired shape formed on the liquid crystal side surface of at least one of the substrates, and the liquid crystal is formed on the upper layer of the color filter layer. In a method for manufacturing a multicolor liquid crystal display element having a protective layer for preventing molding inside, a polyvinyl alcohol aqueous solution containing a photosensitizer is applied to the substrate III on which the electrodes and color filter layers are formed. After drying, a multicolor liquid crystal is characterized in that a protective layer is formed only in the desired area by exposing an image of a desired pattern and developing it using cold water or room temperature water to which an organic acid has been added. A method for manufacturing a display element. (2) As a developer, 20°C or less, preferably about 10°C
Claim No. (1) characterized in that cold water of
). (3) The method according to claim (1), characterized in that water to which 0.01 to 5% by weight of an organic acid is added is used as the developer. (4) The method according to claim (2) or (3), characterized in that acetic acid is used as the organic acid. (5) After development and drying, the protective layer is subjected to a rubbing treatment to impart an orientation function.
The method according to any one of items 1) to (4).