JPH11305235A - Manufacture of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniform a rubbing method to be the alignment processing of a liquid crystal(LC) layer in a liquid cystal display(LCD) device to be used for display and to remove uneven display to be easily generated on half tone display under a large screen and accurate display. SOLUTION: A rubbing roll 4 for rubbing an electrode substrate 10 arranged on one side is arranged on the other side and a dummy substrate 6 obtained by forming an ITO film 2a to be the same material as a display electrode 2 on an optional substrate is simultaneously rubbed by the roll 4. Since respective parts of a rubbing cloth 5 stuck to the surface of the roll 4 rubs the surface of the electrode substrate 10 after rubbing the surface of the dummy substrate 6, the rubbing state of the surface of the alignment layer can be uniformed on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device used for video display equipment, OA equipment such as personal computers and word processors, handy terminal equipment in the industrial field, portable information communication equipment, and the like. .

[0002]

2. Description of the Related Art A liquid crystal display device is inferior in screen size and number of pixels as compared with a CRT, but is small, lightweight and excellent in portability. Currently, as a liquid crystal display device used in notebook computers and word processors, 10
Approximately 12 inches in size, the number of pixels of 640 × 480 dots or 600 × 800 dots is used.
Although the number of pixels of T is inferior, it has excellent display performance as a display.

However, a simple matrix represented by STN (Super Twisted Nematic) has a large screen and a large screen.
There is a demand for uniform display with higher definition. The uniformity of the display is determined by the uniformity of the alignment, which is an index of the arrangement of the liquid crystal molecules, and the uniformity of the gap between the substrates sandwiching the liquid crystal. As a method for controlling the alignment of liquid crystal molecules, a rubbing method in which a cloth such as rayon is wound around a roll surface and the alignment film formed on the substrate surface is rubbed with the tip of the cloth at present is mainly used. This conventional rubbing method will be described with reference to FIGS.

FIGS. 5 and 6 show a rubbing method for an electrode substrate of a conventional liquid crystal display device. FIG. 5 is a sectional view and FIG. 6 is a plan view. 5 and 6, reference numeral 10 denotes an electrode substrate of the liquid crystal display device. A transparent display electrode 2 made of an ITO film is formed on a glass substrate 1, and an alignment film 3 made of polyimide or the like is further formed thereon. Have been. On the other hand, a rubbing cloth 5 made of rayon (for example, YA20R made by Yoshikawa Kogyo) is attached to the surface of the rubbing roll 4 rubbing the surface of the electrode substrate 10 using a double-sided tape. 10
Is set at an angle of 30 degrees with respect to the moving direction (arrow X), and the pushing amount of the rubbing cloth 5 against the substrate surface is 0.55 mm.

[0005] Under these conditions, while rotating the rubbing roll 4 in the direction of the arrow Y, the electrode substrate 10 on which the alignment film 3 is formed is moved in the direction of the arrow X to perform an alignment process (hereinafter referred to as a rubbing process). At this time, the rotation speed of the rubbing roll 4 was 900 rpm, and the moving speed of the substrate was 20 m.
m / sec. At the time of this rubbing treatment, the tip of the rubbing cloth 5 is slid in contact with the surface of the electrode substrate 10 at a certain width (hereinafter referred to as a nip width 8), and the substrate in the contacting part moves to move the rubbing treatment. Is performed.

[0006]

However, it has been found that when such a rubbing treatment is performed, a rubbing state different from the center of the alignment film occurs at the end of the alignment film. FIG.
In the rubbing process, the end of the alignment film 3 on the left side of the substrate passes through a region B12 where the substrate is moved and passes from an area A11 where only the alignment film is rubbed to a region where the electrode terminal is moved to the alignment film. Ends. On the other hand, in the right part, the rubbing process is completed by rubbing while moving from the alignment film portion to the electrode terminal portion, passing through the region A11 from the region C13 in which the alignment film portion is rubbed by one rotation, and ends.

At this time, the rubbing state of the alignment film surface differs depending on the state of the substrate surface through which the tip of the cloth passes, and the areas B and C passing through the electrode terminals are more panel-like than the area A passing only through the alignment film. It was found that the threshold value during the lighting display was slightly higher.

Therefore, in the conventional rubbing method, the threshold value is increased because the region B at the left end is in the final rubbing state, and in the case of high-definition halftone display, the display becomes uneven. There was a problem that was.

The present invention eliminates the delicate threshold non-uniformity that occurs in the conventional rubbing method when realizing a large area, high definition, and high speed of products required in the market in the future, and achieves high display. It is an object of the present invention to provide a method of manufacturing a liquid crystal display device that can obtain high quality.

[0010]

In order to achieve this object, a method of manufacturing a liquid crystal display device according to the present invention comprises the steps of: (1) forming an electrode substrate having a display electrode and an alignment film sequentially formed on at least one main surface; A method of rubbing an alignment film, in which the alignment film is rubbed by a cloth adhered to the surface of a rotating roll, wherein the roll rubbing the electrode substrate located on one side and the dummy substrate located on the other side simultaneously. The dummy substrate is rubbed, and the same material film as the display electrode is formed on an arbitrary substrate, or a glass substrate, and each part of the cloth adhered to the surface of the roll is the dummy substrate. Rubbing the surface of the electrode substrate and then rubbing the surface of the electrode substrate.

According to the above method (1), the tips of the cloth move from the same material film surface or the glass substrate surface as the display electrodes on the dummy substrate to the alignment film surface of the electrode substrate in all the regions. In addition, a uniform rubbing treatment is obtained in the plane of the alignment film, and a threshold value almost equal to that at the center of the alignment film is obtained at the end of the alignment film.

(2) The alignment film of an electrode substrate in which a display electrode and an alignment film are sequentially formed on at least one main surface,
A rubbing method of an alignment film that is rubbed by a cloth stuck on a surface of a rotating roll, wherein the electrode substrate moves in one direction, and the roll slides on the electrode substrate surface at a portion of the electrode substrate. Rotation so that the velocity vector component parallel to the moving direction is opposite to the moving direction of the electrode substrate, the roll rubbing the electrode substrate located on one side, simultaneously rubs the dummy substrate located on the other side, The dummy substrate is formed by forming the same material film as the alignment film on an arbitrary substrate surface.Each portion of the cloth adhered to the surface of the roll rubs the surface of the dummy substrate, and then the electrode It is characterized by rubbing the surface of the substrate.

According to the method (2), the tip of the cloth moves from the same material film surface as the alignment film surface of the dummy substrate to the alignment film surface of the electrode substrate in all regions.
A uniform rubbing treatment is obtained in the plane of the alignment film, and therefore, a threshold value almost equal to that at the center of the alignment film is obtained at the end of the alignment film.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIGS. 1 and 2 show a rubbing method for an electrode substrate of a liquid crystal display element according to Embodiment 1 of the present invention. FIG. 1 is a sectional view thereof,
FIG. 2 is a plan view, and the same components as those of the conventional example are denoted by the same reference numerals. That is, in FIGS.
Reference numeral denotes an electrode substrate of a liquid crystal display device. A transparent display electrode 2 made of an ITO film is formed on a glass substrate 1, and an alignment film 3 made of polyimide or the like is formed thereon. On the other hand, a rubbing cloth 5 made of rayon (for example, YA20R manufactured by Yoshikawa Kogyo) is attached to the surface of the rubbing roll 4 rubbing the surface of the electrode substrate 10 using a double-sided tape. In order to set the twist angle of the layer to 250 degrees, the layer is installed so as to be inclined at 30 degrees with respect to the moving direction (arrow X) of the electrode substrate 10, and the pushing amount of the tip of the rubbing cloth 5 against the substrate surface is 0.55 mm. It has become. The bristle tips of the rubbing cloth 5 are in sliding contact with the surface of the electrode substrate 10 at a nip width 8.

Therefore, the rubbing treatment is performed by moving the electrode substrate 10 on which the alignment film 3 is formed in the direction of the arrow X while rotating the rubbing roll 4 in the direction of the arrow Y, as in the conventional example. At this time, the rotation speed of the rubbing roll 4 was 900 rpm, and the moving speed of the substrate was 20 mm / sec.
And

Further, the first embodiment is characterized in that the rubbing roll 4 that rubs the electrode substrate 10 located on one side simultaneously rubs the dummy substrate 6 located on the other side. On the dummy substrate 6, an ITO film 2a made of the same material as that of the display electrode 2 is formed. The material of the dummy substrate 6 may be a glass substrate or a substrate made of resin or the like.

According to the above-described rubbing method, the rubbing cloth 5 has a bristle tip of the ITO film 2a of the dummy substrate 6 in all regions.
From the surface of the alignment film 3 of the electrode substrate 10, the rubbing treatment is performed under the same conditions at any position of the alignment film surface, and a uniform rubbing surface is obtained in the surface of the alignment film 3. Can be Then, a liquid crystal display element was prepared using the rubbed substrate, and the display quality was confirmed. As a result, a threshold value almost equivalent to that in the plane was obtained even at the edge of the alignment film, and a uniform display state was obtained. It was confirmed that was realized.

In the first embodiment, the case where the ITO film 2a made of the same material as the display electrode formed on the electrode substrate is formed on the surface of the dummy substrate has been described. It has been found that similar effects can be obtained even with a single glass substrate on which no film is formed.
In this case, the rotating direction of the rubbing roll 4 with respect to the moving direction of the electrode substrate 10 may be any direction.

Further, the film formed on the surface of the dummy substrate is
In some cases, a similar effect can be obtained even with a film made of a material different from that of the display electrode.

(Embodiment 2) FIGS. 3 and 4 show a method of manufacturing a liquid crystal display element according to Embodiment 2 of the present invention. FIG. 3 is a cross-sectional view and FIG. 4 is a plan view. .
In the second embodiment, the rubbing roll 4 rotates in the arrow Y direction while the electrode substrate 10 moves in the arrow X direction. However, the rubbing roll 4 is inclined by 30 degrees with respect to the moving direction of the electrode substrate 10 in order to make the twist angle of the liquid crystal layer 250 degrees. That is, the rubbing roll 4
Is rotated so that a velocity vector component parallel to the moving direction of the electrode substrate at a portion in sliding contact with the surface of the electrode substrate 10 is in a direction opposite to the moving direction of the electrode substrate 10.

Further, the rubbing roll 4 for rubbing the electrode substrate 10 located on one side simultaneously rubs the dummy substrate 7 located on the other side. The dummy substrate 7 is provided on the surface of a glass substrate, for example, on the electrode substrate 10.
The same material film 3a as the alignment film 3 formed thereon is formed. Therefore, each part of the rubbing cloth 5 stuck on the surface of the rubbing roll 4 rubs the surface of the dummy substrate 7 and then rubs the surface of the electrode substrate 10.

According to the second embodiment configured as described above, the tips of the rubbing cloth 5 in all regions are aligned with the electrode substrate 10 from the surface of the same material film 3 a as the alignment film 3 in the dummy substrate 7. The film moves to the surface of the film 3 and a uniform rubbing treatment is obtained within the surface of the alignment film. As a result, a threshold value almost equal to that at the center of the alignment film is obtained at the edge of the alignment film. .

[0024]

As described above, according to the present invention, in a rubbing method for aligning a liquid crystal display element, a dummy substrate on which a rubbing roll simultaneously rubs is disposed outside an electrode substrate on which an alignment film is formed. And the dummy substrate is
When the same material film as the display electrode is formed, or when the glass substrate is used alone, or when the rotation direction of the rubbing roll is reversed from the moving direction of the electrode substrate, the same material film as the alignment film is formed on the dummy substrate. By doing so, it is possible to make the rubbing state of the alignment film surface uniform within the plane, and therefore, the threshold value at the edge of the alignment film is almost the same as that at the center. Even on screen size monitors and STN movie displays,
There is an effect that a beautiful display screen can be obtained with the liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a method for manufacturing a liquid crystal display element in Embodiment 1 of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a cross-sectional view illustrating a method for manufacturing a liquid crystal display element in Embodiment 2 of the present invention.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a sectional view of a conventional example.

FIG. 6 is a plan view of FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 glass substrate 2 display electrode 3 alignment film 4 rubbing roll 5 rubbing cloth 6,7 dummy substrate 8 nip width X moving direction of electrode substrate Y rotating direction of rubbing roll 10 electrode substrate 11 area A 12 area B 13 area C

Claims (3)

[Claims] 1. A method for rubbing an alignment film in which an alignment film of an electrode substrate having a display electrode and an alignment film sequentially formed on at least one principal surface is rubbed by a cloth adhered to a surface of a rotating roll. The roll that rubs the electrode substrate located on one side,
Simultaneously rubs the dummy substrate located on the other side, the dummy substrate is formed of the same material film as the display electrode on an arbitrary substrate, or is formed of a glass substrate, and is adhered to the surface of the roll. Each part of the cloth rubs the surface of the dummy substrate and then rubs the surface of the electrode substrate. 2. The dummy substrate has a solid ITO surface on its surface.
2. The method according to claim 1, wherein a film is formed or an ITO film having an arbitrary circuit pattern is formed. 3. A method for rubbing an alignment film in which an alignment film of an electrode substrate having a display electrode and an alignment film sequentially formed on at least one main surface is rubbed with a cloth adhered to the surface of a rotating roll. The electrode substrate is moved in one direction, and the roll is moved so that a velocity vector component parallel to the moving direction of the electrode substrate in a portion in sliding contact with the surface of the electrode substrate is in a direction opposite to the moving direction of the electrode substrate. The roll that rotates to rub the electrode substrate located on one side,
Simultaneously rub the dummy substrate located on the other side, the dummy substrate is made of a substrate on which the same material film as the alignment film is formed, and each part of the cloth stuck on the surface of the roll is After rubbing the surface of the dummy substrate, rubbing the surface of the electrode substrate.