JP2731060B2 - Manufacturing method of liquid crystal display element - Google Patents

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, and more particularly, to an alignment treatment method after coating an alignment film.

[0002]

2. Description of the Related Art Conventionally, a rubbing method has been used as an alignment treatment method after coating an alignment film in a manufacturing process of a liquid crystal display element. In this method, for example, an alignment treatment is performed by rubbing a synthetic resin such as polyimide as an alignment film material fixed on a glass substrate in one direction using a cloth or the like.

FIG. 6 is a diagram showing a specific configuration of an alignment treatment apparatus used in the rubbing method. In FIG.
The rubbing roller 1 is for performing an alignment treatment by contacting a substrate 2 on which an alignment film material such as polyimide is applied, and a cloth is stuck over the entire outer peripheral surface. The rubbing roller 1 has a roller support shaft 3 inserted therein, and is further supported by support columns 4 at both ends of the roller support shaft 3, and is configured to be rotatable by a drive mechanism (not shown). The rubbing stage 5 includes a rubbing roller 1.
And the substrate 2 is arranged at a position where the substrate 2 can be brought into contact with the rubbing roller 1, and is mounted on a stage table 6 which moves in synchronization with the rotation of the rubbing roller 1.

During the alignment process, the rubbing roller 1 is rotated, and the stage 6 is relatively moved to rub the alignment film material on the substrate 2 with the cloth stuck on the outer peripheral surface of the rubbing roller 1. I do.

[0005]

The above-mentioned alignment processing apparatus which performs alignment processing by rubbing the alignment film material formed on the substrate with a cloth or the like has the following disadvantages.

At the time of orientation processing, the rubbing roller 1 needs to be rotated at a relatively high speed, and the stage table 6 is also relatively moved, so that the driving mechanism becomes complicated and the apparatus becomes large.

Further, since the alignment film treatment is performed using consumables such as cloth, material costs are high.

In the case where the rubbing roller 1 performs the orientation treatment, the cloth adhered to the rubbing roller 1 comes into contact with the orientation film on the substrate only near the linear portion along the rotation axis of the roller 1. For this reason, the state of contact with the alignment film on the substrate changes due to a variation in the amount of hair per unit area of the cloth and a variation in the length of the hair. Processing becomes difficult.

Further, when an alignment film formed on a large-sized substrate is subjected to an alignment treatment, the above-mentioned difference in the strength of the rubbing treatment due to the change in the contact state becomes more remarkable, and a uniform alignment treatment is performed as a whole. It becomes difficult.

In addition, since the orientation treatment is performed using a cloth or the like,
If the formed alignment film is contaminated during the fabric manufacturing process, it may be affected.

Therefore, an object of the present invention is to provide a method of manufacturing a liquid crystal display element which can perform an alignment treatment in a manufacturing process of the liquid crystal display element with a simple structure without using a cloth or the like. is there.

[0012]

According to the present invention, a pair of substrates on each of which an alignment film is formed are stacked on each other, and the substrates are pressed in the direction of their planes while these substrates are pressed. A method for manufacturing a liquid crystal display element, characterized in that the liquid crystal display elements are mutually displaced along.

Further, the present invention is characterized in that the alignment film is heated to near a plasticizing temperature.

[0014]

According to the present invention, the alignment films of a pair of substrates each having an alignment film formed thereon are overlapped with each other so as to face each other, and these substrates are pressed. To displace the substrates. Thereby, the polymer chains of the alignment film are stretched in a certain direction, and the alignment films of the two substrates are simultaneously and uniformly aligned.

Further, according to the present invention, the alignment film is heated to a temperature close to the plasticizing temperature, whereby the alignment treatment can be performed more easily, and the alignment state of the liquid crystal molecules when the liquid crystal display device is manufactured can be improved. Can be.

[0016]

FIG. 1 is a schematic view showing an alignment processing method according to a first embodiment of the present invention, and FIG. 2 is a process chart showing an operation during the alignment processing. The operation during the alignment process will be described with reference to FIGS.

First, in step a1, as shown in FIG. 1A, a substrate 7 and a substrate 8 having an alignment film formed on the surface are prepared. One piece of the substrate 7 has a square shape of, for example, 30 cm, and polyimide, for example, Optmer manufactured by Nippon Synthetic Rubber Co., Ltd. is coated on the surface as a material for the alignment film. The substrate 8 is a substrate having the same size as the substrate 7, and the surface thereof is coated with an alignment film material similarly to the substrate 7. In FIG. 1, the surface on which the alignment film material is applied is indicated by hatching. The same applies to FIGS. 4, 6 and 9 described later.

Next, in step a2, the alignment film surfaces of the substrate 7 and the substrate 8 are overlapped with each other. In step a3, a uniform pressure distribution, for example, 300 kg / cm ² is applied in this overlapped state. The substrate 8 is moved in the direction of the arrow R1 shown in FIG. As a result, the polyimide 10 on the substrates 7 and 8 is uniformly stretched in the direction in which it has been moved, and is subjected to an alignment treatment.

When the birefringence of the substrates 7 and 8 subjected to this treatment was measured, the birefringence showed a value of about 1 nm perpendicular to the moving direction, indicating that the polymer chains of the polyimide 10 were stretched. . This value was uniform in the substrates 7 and 8. Further, when a liquid crystal display element was prepared using the substrates 7 and 8, a uniform and favorable alignment state of liquid crystal molecules could be realized over the entire surface of the substrate.

FIG. 3 is a sectional view of the substrates 7 and 8 described above. The substrates 7 and 8 to be subjected to the alignment treatment shown in FIG.
Is obtained by forming polyimide 10 as an alignment film material on a transparent glass substrate 9. The substrates 7 and 8 to be subjected to the alignment treatment shown in FIG. 3 (2) have a transparent electrode 11 formed on a transparent glass substrate 9 and a polyimide 10 as an alignment film material formed thereon. It is. As described above, the alignment treatment method according to the present invention can also be performed on a substrate on which the transparent electrode 11 has been formed before performing the alignment treatment.

As described above, according to the first embodiment, the alignment film surface of the alignment film material formed on the substrate 7 is changed to the alignment film surface of the substrate 8 formed with the same size of the alignment film material. Since they are superposed and moved along the direction of the plane while being pressed with a uniform pressure distribution, the polymer chains of the mutual alignment films are stretched in a certain direction, and uniform alignment processing can be performed.

Also, since the moving distance of the substrates 7 and 8 during the alignment process is short and the number of driving parts such as devices required for the alignment process is smaller than that of a conventional rubbing device, an apparatus for the alignment process is required. It is possible to reduce the size.

Further, since a cloth or the like is not used for the alignment treatment, the material cost can be reduced, and contamination of the alignment film due to the adhesion of the fiber of the cloth is eliminated.

FIG. 4 is a schematic view showing an alignment treatment method according to a second embodiment of the present invention. This embodiment is characterized in that hot air is blown to heat the polyimide 10 on the substrates 7 and 8 to near the plasticizing temperature during the alignment process.

FIG. 5 is a process chart showing an alignment treatment method in the second embodiment. The operation during the alignment process will be described with reference to FIGS. First, in step b1, a substrate 7 and a substrate 8 having an alignment film formed on the surface are prepared. Next, in step b2, the alignment film surfaces of the substrate 7 and the substrate 8 are overlapped with each other, and hot air is blown from the hot air nozzle 12 to heat the polyimide 10 to a temperature close to the plasticization temperature (to 180 ° C.). In step b3, the substrate 8 is pressed with a uniform pressure distribution in this superimposed state while heating is continued, and the substrate 8 is moved in the arrow R2 direction shown in FIG. Thereby, the polyimide 10 on the substrates 7 and 8 is uniformly stretched in the moving direction.

As described above, according to the second embodiment, the first
In addition to the effects of the embodiment, by preliminarily heating the polyimide 10 to around the plasticizing temperature, the alignment treatment can be performed more easily, and the alignment state of the liquid crystal molecules when the liquid crystal display element is manufactured can be changed. Can be improved.

Further, since the apparatus for the alignment treatment can be miniaturized, a function for heating the alignment film such as the hot air nozzle 12 can be incorporated in the apparatus.

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

As described above, according to the present invention, since the alignment treatment of the alignment film can be performed without using a cloth or the like, the apparatus for the alignment processing does not become large. In addition, the alignment films are pressed while facing each other,
Since the substrates are displaced from each other along the direction of their planes, thereby stretching the polymer chains of the alignment film and performing the alignment process, even when the alignment film material on a large substrate is to be aligned. In addition, a uniform pressure is applied to the whole alignment film material, and a uniform alignment process can be performed on the whole. Also,
Since a cloth is not used in the alignment treatment, the formed alignment film can be prevented from being affected by contamination of the cloth itself. Further, according to the present invention, the alignment film can be heated to a temperature close to the plasticization temperature, whereby the alignment treatment can be performed more easily, and the alignment state of the liquid crystal molecules when a liquid crystal display device is manufactured can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an alignment treatment method according to a first embodiment of the present invention.

FIG. 2 is a process chart showing an alignment treatment method according to a first embodiment.

FIG. 3 is a cross-sectional view of substrates 7 and 8 to be subjected to an alignment process.

FIG. 4 is a schematic view illustrating an alignment treatment method according to a second embodiment of the present invention.

FIG. 5 is a process chart showing an alignment treatment method according to a second embodiment.

FIG. 6 is a view showing a conventional alignment processing apparatus.

[Explanation of symbols]

 7, 8 substrate 9 transparent glass substrate 10 polyimide 11 transparent electrode 12 hot air nozzle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masako Okada 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Masahiro Adachi 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation (72) Inventor Shinji Shimada 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-1-251015 (JP, A)

Claims (2)

(57) [Claims] 1. A method in which a pair of substrates each having an alignment film formed thereon is overlapped with each other, and the substrates are mutually displaced along the direction of their planes while these substrates are pressed. A method for manufacturing a liquid crystal display element, which is characterized by the following. 2. The method according to claim 1, wherein the alignment film is heated to a temperature near a plasticizing temperature.