JPH06230385A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To produce the liquid crystal display element which is suppressed in build-up of the liquid pool at the rear end of a protective film and has a high display grade. CONSTITUTION:Ink for forming the protective film is transferred in recessed parts 2b formed between projecting parts 2a and projecting parts 2a of a letterpress 2 on which plural projecting parts 2a... are formed on the surface. The surface of the letterpress 2 and the surface of a glass substrate are brought into contact with each other and the ink transferred into the recessed parts 2b is transferred to the surface of the letterpress 2 and the surface of the glass substrate to form the protective film on the surface of the glass substrate. The ratio occupied per unit area of the projecting parts 2a... of the letterpress 2 varies between the region H1 from the front end side A to the rear end side B in the printing direction and the region H2 on the rear end side, and is made high in the region H2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device having an alignment film, a protective film and the like formed by using a relief printing plate having a plurality of projections formed on its surface.

[0002]

2. Description of the Related Art In general, a liquid crystal display device has a pair of substrates made of glass or the like which are bonded to each other via a spacer, and a transparent conductive film, a protective film, an alignment film are provided on respective facing surfaces of these substrates. Etc. are stacked. In such a liquid crystal display device, a transparent conductive film, a protective film, and an alignment film are sequentially formed on a substrate, and after the alignment film is rubbed, the film forming surfaces are opposed to each other with a sealant containing a spacer. They are bonded together in the state of being made, and a liquid crystal material is injected between the substrates to manufacture.

By the way, among a plurality of films formed on the above-mentioned substrate, the transparent conductive film is formed by a vacuum vapor deposition method or a sputtering method, but the protective film, the alignment film and the like are formed in terms of workability and cost. , The ink for forming each film is transferred by a letterpress printing method.

That is, as shown in FIGS. 7 (a) and 7 (b) and FIG. 2 (a) which is an explanatory view of the present invention, a large number of substantially conical projections 30a ... Convex part 3
The relief plate 30 having the recesses 30b between 0a is wound around the outer periphery of the printing roller 1 to rotate in the B direction,
At the same time, the glass substrate 5 is conveyed in the direction A by the stage 4 provided below, and when the surface of the relief plate 30 and the surface of the glass substrate 5 come into contact with each other, a predetermined film transferred to the concave portion 30b of the relief plate 30 is formed. A printing film is formed on the substrate 5 by transferring the ink for printing onto the surface of the relief plate 30 and the surface of the substrate 5.

Conventionally, as the relief plate 30, the amount of ink transferred to the glass substrate 5 is the same in any part, and a convex part per unit area is formed so that a printed film having a uniform film thickness can be formed. A letterpress is used in which the proportion of the portions 30a ... Is equal (for example, 30% of the entire area).

[0006]

However, in the above-mentioned conventional method, since the printing film is formed by using the relief plate 30 that transfers an equal amount of ink to all the portions on the glass substrate 5, the glass substrate is formed. Excess ink is likely to collect on the edge portion on the rear end side in the printing direction of the print film formed in 5,
This ink forms a liquid pool that rises above the surface of the printed film, and this causes unevenness in contrast when it is operated as a liquid crystal display element, resulting in problems such as deterioration in display quality. . That is, as shown in FIG. 8, on the glass substrate 31 on which the transparent conductive film 32 is formed,
When the protective film 33 and the alignment film 34 are sequentially formed using the relief plate 30, the liquid pool 33 a of the protective film 33 may be larger than the liquid pool of the alignment film 34. Then, FIG. 9 (a)
As shown in (b), (c) and (d), when the rubbing process is performed on the alignment film 34 using the rubbing cloth 35, the liquid pool 33a is formed.
The upper part of the shavings is scraped by the rubbing cloth 35, and the shavings 33a ′ ... Are transferred onto the alignment film 34. Shavings 3
The orientation of the orientation film 34 to which 3a '... Is transferred is disturbed, which causes uneven contrast.

[0007]

In order to solve the above-mentioned problems, a method of manufacturing a liquid crystal display device according to the present invention is provided between a convex portion and a convex portion in a relief plate having a plurality of convex portions formed on the surface thereof. Ink for forming a printing film was transferred to the formed recess, and the relief plate surface and the surface of the substrate on which the liquid crystal display element was formed were sequentially contacted from one side, and at the time of this contact, the ink was transferred to the recess. Ink, by transferring to the letterpress surface and the substrate surface, in the method of manufacturing a liquid crystal display element to form a printed film on the substrate surface, the proportion of the convex portion per unit area on the rear end side in the printing direction, It is characterized by using a relief printing plate formed to be different from the portion other than the rear end side.

[0008]

According to the above method, since the proportion of the convex portion per unit area on the trailing end side in the printing direction is different from that on the portion other than the trailing end side, the relief printing plate is used. The amount of ink transferred to the rear end side of the substrate is different from that of other portions.

For example, when a printing film is formed by using a relief printing plate in which the diameter of the convex portion in the area of about 5 mm inward from the rear end portion is larger than the diameter of the convex portion formed in the other portion, when the printing film is formed, Since the amount of ink transferred to the rear end side increases, the amount of ink supplied to the liquid pool formed at the edge portion on the rear end side decreases, and the liquid pool is prevented from rising significantly.

Contrary to the above, for example, a printing plate is formed by using a relief printing plate in which the diameter of the convex portion in the area of about 5 mm inward from the rear end portion is smaller than the diameter of the convex portion formed in the other portion. In the case of forming, the amount of ink transferred to the rear end side of the substrate is reduced, so that the film thickness on the rear end side of the printed film becomes thin. Since the ink that forms the liquid pool flows into the thin portion, the amount of ink that is supplied to the liquid pool is reduced, and this also prevents the liquid pool from rising significantly.

Therefore, for example, it is possible to solve the problem that the alignment property of the alignment film is lowered, and it is possible to manufacture a liquid crystal display element having high display quality.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will explain one embodiment of the present invention with reference to FIGS.

In the liquid crystal display device manufactured by the manufacturing method according to the present invention, as shown in FIGS. 3 and 4, first, the transparent conductive film 2 is vapor-deposited on the glass substrate 5 which is the substrate of the liquid crystal display device. (P1) and patterned (P2). Next, a protective film 7 which is a printing film is formed on this by a film printing apparatus described later (P3), and after a washing step (P4),
The alignment film 8 which is a print film is formed by the film forming apparatus (P5). When the alignment film 8 is formed, the rubbing process using the rubbing cloth described above is performed, and the alignment property is imparted to the alignment film 8 (P6). After that, spacers (not shown) are sprinkled on the alignment film 8, and then the pair of glass substrates 5 and 5 are bonded with the film formation surfaces facing each other (P7 and P8).
A liquid crystal material is injected between the substrates and sealed (P9).

The film printing apparatus for forming the protective film 7, the alignment film 8 and the like forms the protective film 7, the alignment film 8 and the like on the glass substrate 5 as shown in FIGS. 2 (a) and 2 (b). Printing plate 1 that rotates the letterpress 2 that transfers ink for printing (hereinafter, simply referred to as ink) and the letterpress 2 that is wound around the outer periphery in the B direction.
And a stage 4 which is arranged below the printing roller 1 and conveys the placed glass substrate 5 in the A direction, and a stage 4 which is arranged in contact with the surface of the relief plate 2 and is rotated in the C direction to cause the ink on the relief plate 2. And an squeegee 10 which is disposed in contact with the ink transfer roller 9 and applies ink to the ink transfer roller 9.

As shown in FIGS. 1A and 1B, the relief plate 2 is
A large number of convex portions 2a ... Which are substantially conical are formed on the surface of, and concave portions 2b are formed between the convex portions 2a. The ink transferred from the ink transfer roller 9 is stored in the recess 2b, and the ink is transferred onto the glass substrate 5 to form a print film.

The amount of ink stored in the concave portion 2b of the region H ₂ 5 mm inward from the rear end in the printing direction (the range which does not correspond to the display portion when configured as a liquid crystal display element) is the region H which is the other portion. It is formed so as to be less than the amount of ink stored in the _one recess 2b. That is, the recess 2b
The amount of ink reserved in the proportion of the convex portion 2a ... per unit area, because it depends on (the area ratio of the convex portion 2a ... and the recess 2b), the convex portion 2a of the region H ₁ ... are per unit area protrusions 2a ... occupied opening ratio which is a ratio is formed so as to be 30%, whereas, the convex portion 2a ... region H _2, the convex portion 2a ... large diameter more areas H _1, aperture ratio It is formed to be 50%.

When the protective film 7 as a printed film is formed on the glass substrate 5 by the film printing apparatus having the above structure, first,
The squeegee 10 applies ink to the outer peripheral surface of the ink transfer roller 9 which rotates in the C direction. Ink transfer roller 9
The ink applied to the outer peripheral surface of the is transferred to the concave portion 2b on the surface of the relief plate 2 rotating in the B direction due to the contact between the ink transfer roller 9 and the relief plate 2.

The surface of the relief plate 2 rotating in the B direction and the surface of the glass substrate 5 on which the transparent conductive film 6 on the stage 4 moving in the A direction is formed are the front end side to the rear end of the relief plate 2. When they are sequentially contacted toward the side, the ink transferred to the concave portions 2b of the relief plate 2 is transferred to the surface of the relief plate 2 and the glass substrate 5, and the protective film 7 is formed on the transparent conductive film 6 (see FIG. (See a) and (b)).

As described above, the area H _{2 of the} relief printing plate 2 is formed so that the amount of ink stored therein is smaller than that of the area H _1. Therefore, the amount of ink used for printing on the trailing edge side is small. Therefore, the film thickness on the rear end side of the protective film 7 becomes thin. When the film thickness on the rear end side becomes thin, the liquid pool 7 formed on the rear end part
The ink supplied to a flows into the thin film portion, and FIG.
As shown in, a flat liquid reservoir 7a is formed.

Therefore, an alignment film 8 is formed on this,
Even if the alignment film 8 is subjected to a rubbing treatment, there is no fear that the liquid pool 7a of the protective film 7 will be scraped off by a rubbing cloth, so that the alignment property of the alignment film 8 is not disturbed, and there is no contrast unevenness, and the display quality is good. A high liquid crystal display device can be manufactured.

[0021] In the above-described relief plate 2, the opening ratio of area H ₁ to 30%, but the aperture ratio of the area H ₂ was 50%, for example, as shown in FIG. 5, the aperture ratio of the area H ₂ Is 40
%, 50% may be changed in this order to the letterpress 2 ',
It is not limited to these. Similarly, the numerical aperture indicating the area H ₁ and the area H ₂ are not limited to these values.

Contrary to the above, as shown in FIG.
A configuration in which the aperture ratio of the region H ₂ is gradually lowered to 20% and 10% is also possible. When printing with such a letterpress 2 ″, the amount of ink used for printing on the trailing edge side increases, so the amount of ink used for the liquid pool decreases, and it is possible to prevent the liquid pool from rising significantly. The same effect as above can be obtained.

[0023]

As described above, in the method of manufacturing a liquid crystal display device according to the present invention, the proportion of the convex portion per unit area on the rear end side in the printing direction is made different from that on the portion other than the rear end side. The formed relief plate is used.

As a result, it is possible to prevent a large swelling of the liquid pool from being formed at the trailing edge of the print film in the printing direction, and it is possible to solve the problem that the alignment property of the alignment film is lowered. Therefore, there is an effect that a liquid crystal display element having high display quality can be manufactured.

[Brief description of drawings]

1A and 1B show an embodiment of the present invention, FIG. 1A is a plan view of a relief plate provided in a film printing apparatus for forming a printing film, and FIG. 1B is a line E shown in FIG. It is sectional drawing in -E.

FIG. 2 is a configuration diagram of the film printing apparatus.

FIG. 3 is a process drawing showing a manufacturing process of a liquid crystal display element.

FIG. 4 is a cross-sectional view of a main part of a substrate on which a protective film and an alignment film are formed by the film printing apparatus.

FIG. 5 shows another embodiment of the present invention, (a)
Is a plan view of a relief plate used for forming a print film, and FIG. 9B is a cross-sectional view taken along line FF shown in FIG.

FIG. 6 shows another embodiment of the present invention, (a)
Is a plan view of a relief plate used for forming a print film, and (b) is a cross-sectional view taken along line GG shown in (a).

7A is a plan view of a conventional letterpress used for forming a print film, and FIG. 7B is a cross-sectional view taken along line DD shown in FIG. 7A.

8 is a cross-sectional view of an essential part of a substrate on which a protective film and an alignment film are formed using the relief printing plate shown in FIG.

9 (a), (b), (c), and (d) are explanatory views showing a state of a rubbing treatment of the substrate shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 printing roller 2 letterpress 2'letterpress 2 '' letterpress 2a convex part 2b concave part 4 stage 5 glass substrate 6 transparent conductive film 7 protective film 8 alignment film 9 ink transfer roller 10 squeegee

Claims (1)

[Claims] 1. An ink for forming a printing film is transferred to a concave portion formed between a convex portion and a convex portion in a relief plate having a plurality of convex portions formed on the surface, and the relief plate surface and a liquid crystal display. Contact the surface of the substrate on which the element is formed from one side in order,
At the time of this contact, the ink transferred to the recess is transferred to the relief plate surface and the substrate surface to form a print film on the substrate surface. A method for manufacturing a liquid crystal display element, which comprises using a relief printing plate which is formed by making the ratio of the convex portion per area different from the portion other than the rear end side.