JPH06138461A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To produce the liquid crystal display element with which a uniform display is obtainable at a good yield. CONSTITUTION:Dummy substrates are previously rubbed by the same method as for the rubbing orientation treatment to which the respective opposite surfaces of two sheets of transparent electrode substrates 5, 6 disposed to face each other via liquid crystal 8 are subjected to rubbing materials consisting of cloth and are aged at the time of subjecting the opposite surfaces of the substrates to the rubbing orientation treatment by the rubbing materials. The transparent electrode substrates 5, 6 are subjected to the rubbing orientation treatment by these aged rubbing materials.

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 element, and more particularly to a method of manufacturing a liquid crystal display element in which the rubbing alignment treatment of the respective facing surfaces of transparent electrode substrates which are opposed to each other with a liquid crystal interposed therebetween is improved. .

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device has been arranged to obtain a desired viewing angle characteristic and display characteristic by aligning the liquid crystal filled between two transparent electrode substrates, that is, by arranging the liquid crystal in one direction.
An orientation treatment is performed in the manufacturing process. As this alignment treatment, a rubbing alignment treatment method of rubbing the opposite surfaces of two transparent electrode substrates is widely used.

Generally, in the rubbing orientation treatment method, a cloth such as rayon or cotton is used as a rubbing material, which is attached or wound around a cylinder, a plate or the like, and particularly in the case of a cylinder, it is rotated at a predetermined rotation speed. , The surface of the substrate on which the transparent electrode is formed is rubbed in one direction with the cloth on the surface. This rubbing alignment treatment method is similarly performed on a transparent electrode substrate having an alignment film made of a polyimide resin or the like formed on a transparent electrode.

However, in the conventional rubbing orientation treatment method,
Depending on the initial state of the rubbing material, there is a problem that the orientation state is not uniform and the orientation is non-uniform. That is, in general, the cloth of the rubbing material has a non-uniform direction of the hair tips, and therefore, if the rubbing orientation treatment is performed in such a state, the hair tips are not aligned in the intended orientation direction, and as a result, the orientation direction is the target. The orientation of the liquid crystal molecules becomes unstable, causing unevenness of the screen of the liquid crystal display element and non-uniformity of display.

Further, in the conventional rubbing orientation treatment method, the chemical structure of the surface of the rubbing material becomes non-uniform due to the adherence of contaminants in the rubbing material manufacturing step or the variation in the rubbing material manufacturing step, and the like. The contaminants may be transferred to the electrode substrate side or the non-uniform chemical structure may be attached as it is, resulting in non-uniform alignment. Further, dust such as dust generated when the rubbing material is cut may cause contamination such as mixing into the liquid crystal display element, resulting in uneven display, uneven alignment state, and reduction in yield due to mixing. Cause problems.

In particular, in recent years, the super-twisted nematic liquid crystal display device, which has become the mainstream of liquid crystal display devices, has a pretilt structure in which liquid crystal molecules are tilted from the alignment treated surface during alignment treatment. Since the display element has a sharper threshold characteristic than the nematic liquid crystal display element, depending on the initial state of the rubbing material, the pretilt structure is likely to be affected, which causes non-uniformity of display and lower yield. There's a problem.

[0007]

As described above, the rubbing alignment treatment method of rubbing with a rubbing material has been generally performed as the alignment treatment of the liquid crystal display element. However, in this rubbing alignment treatment method, (a) the directions of the tips of the surface of the rubbing material are not uniform, the alignment directions are not uniform, and the alignment state of liquid crystal molecules becomes unstable. (B) Contamination of the rubbing material When the substance is attached, the contaminant is transferred to the transparent electrode substrate side, and the alignment state of liquid crystal molecules becomes unstable. (C) When the chemical structure of the surface of the rubbing material is non-uniform,
The non-uniform chemical structure directly adheres to the transparent electrode substrate side, and the alignment state of liquid crystal molecules becomes unstable. (D) Dust such as dust generated when cutting the rubbing material causes contamination of the liquid crystal display element, There are problems such as non-uniformity of display, non-uniformity of alignment state, and reduction of yield due to mixing.

The present invention has been made in order to solve the above-mentioned problems, and during rubbing orientation treatment, the bristles of the rubbing material are forced in one direction, and contaminants transferred from the rubbing material. An object of the present invention is to obtain a method for producing a liquid crystal display element, which can prevent the entry of dust and can stably produce a liquid crystal display element having a uniform orientation and high display quality.

[0009]

In a method of manufacturing a liquid crystal display element, when the respective facing surfaces of two transparent electrode substrates which are opposed to each other with a liquid crystal interposed therebetween are subjected to rubbing alignment treatment with a rubbing material made of cloth, for example, in advance, The dummy substrate was rubbed by the same method as the rubbing orientation treatment to age the rubbing material, and the transparent electrode substrate was rubbing orientation treated by the aged rubbing material.

[0010]

As described above, the dummy substrate is rubbed by the same method as the rubbing orientation treatment to age the rubbing material, and the transparent electrode substrate is rubbing oriented by the aged rubbing material. The bristles can be aligned in the same direction, contaminants on the surface of the rubbing material can be removed, the chemical structure on the surface of the rubbing material can be made uniform, and dust adhering to the rubbing material can be removed. Processing can be performed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a liquid crystal display device manufactured by the embodiment. In this liquid crystal display element, transparent electrodes 1 and 2 having a predetermined pattern are formed on the opposite surface.
Two transparent electrode substrates 5, on which the alignment films 3 and 4 are formed,
6, a sealing material 7 that separates the transparent electrode substrates 5 and 6 by a predetermined distance and adheres their peripheral portions, and a liquid crystal 8 that is surrounded by the sealing material 7 and that is filled between the transparent electrode substrates 5 and 6. , And a polarizing plate 9 provided on the outer surface of each transparent electrode substrate 5, 6.

This liquid crystal display device is manufactured by first forming transparent electrodes 1 and 2 each having a predetermined pattern on opposite surfaces of two transparent substrates.
2 is formed, and then the alignment films 3 and 4 are formed on the electrodes 1 and 2, respectively, and then the alignment films 3 and 4 are subjected to rubbing alignment treatment.

In this rubbing orientation treatment, a rubbing material made of cloth adhered or wound around a cylindrical substrate is rotated at a predetermined rotation speed, and each orientation film 3,
This is performed by rubbing the entire surface of 4 in one direction. In the manufacturing method of this example, the rubbing material attached to the cylindrical substrate is aged, and the rubbing orientation treatment is performed using the aged rubbing material.

In the aging, as shown in FIG. 2, a transparent electrode 12 and a dummy substrate 14 having an alignment film 13 formed thereon are placed on a stage 11 in the same manner as the transparent electrode substrate of the liquid crystal display element. The rubbing material 16 attached to the cylindrical substrate 15 is used to rub the dummy substrate 14 a plurality of times under the same conditions as the rubbing orientation treatment. In this way, when the dummy substrate 14 is rubbed a plurality of times under the same conditions as the rubbing orientation treatment, the bristles of the rubbing material 16 are forced in one direction and aligned in the same direction. Further, the contaminants on the surface of the rubbing material 16 are transferred to the dummy substrate 14, so that the contaminants remaining on the rubbing material 16 are small, and
16 Spread evenly on the surface. The chemical structure of the surface of the rubbing material 16 is also made uniform by the same effect. Further, dust such as dust generated by cutting the rubbing material 16 is also removed.

Then, next, using the aged rubbing material 16, the alignment film 3 of the transparent electrode substrates 5 and 6 is formed.
, 4 is rubbed in one direction while rotating at a predetermined rotation speed.

The manufacturing of the liquid crystal display element is carried out after that by the one transparent electrode substrate 5 which has been subjected to the rubbing alignment treatment.
(Or 6) A sealing material 7 is applied by printing on the peripheral portion of the facing surface of (or 6), leaving a portion to be a liquid crystal injection port, and then one transparent electrode substrate 5 to which this sealing material 7 is applied.
(Or 6) and the other transparent electrode substrate 6 (or 5) are adhered with a sealing material 7 to form two transparent electrode substrates 5
, 6 face each other at a predetermined interval and have a liquid crystal injection port. Then, liquid crystal is injected between the two transparent electrode substrates 5 and 6 of this display panel through the liquid crystal injection port,
It is manufactured by sealing the liquid crystal injection port.

By the way, as described above, the transparent electrode substrate 5,
When performing rubbing alignment treatment on each of the alignment films 3 and 4 of 6, the rubbing material 16 used for the rubbing alignment treatment is aged using a dummy substrate 14 having the same structure as the transparent electrode substrates 5 and 6 of the liquid crystal display element. When the rubbing orientation treatment is performed using the aged rubbing material 16, the direction of the bristles of the rubbing material 16 is aligned by the aging, the contaminants on the surface of the rubbing material 16 are removed, and the chemical structure of the surface of the rubbing material 16 is made uniform. By removing the dust adhering to the rubbing material 16, the transparent electrode substrates 5 and 6 can be subjected to a required rubbing alignment treatment that does not disturb the alignment of the liquid crystal molecules. As a result, the alignment state of the liquid crystal molecules becomes uniform, and a liquid crystal display element capable of uniform display without display unevenness can be manufactured with high yield.

That is, as a result of comparing the liquid crystal display device, which has been subjected to the rubbing orientation treatment with the rubbing material 16 aged as described above, with the liquid crystal display device manufactured by the conventional method without aging, rubbing with the aged rubbing material 16 is performed. The liquid crystal display element subjected to the alignment treatment was clearly improved in display quality and yield as compared with the liquid crystal display element manufactured by the conventional method.

As the aging of the rubbing material 16, it is preferable to rub the dummy substrate 14 about 20 to 40 times. If it is less than 20 times, the effect of aging is weakened, and if it exceeds 40 times, the dummy substrate 14 is rubbed. The contaminants and dust transferred to 14 reattach to the rubbing material 16, and the rubbing material 16 is re-contaminated.

It is desirable that the aging treatment is carried out under the same conditions as the rubbing orientation treatment, but if the number of revolutions of the rubbing material and the amount of rubbing material applied to the rubbing orientation treatment are the same as those of the rubbing orientation treatment, then the rubbing treatment is performed on the substrate. The effect of aging can be obtained even if it is fixed without moving. When performing aging under these conditions, the number of substrates for aging corresponding to the above-mentioned embodiment may be replaced with the aging time.

Further, not only the substrate to be rubbed but also a substrate having only the electrode film formed on the entire surface can be applied to the aging treatment.

Although the liquid crystal display device having the alignment film has been described in the above embodiment, the present invention can be applied to the liquid crystal display device having no alignment film.

Further, the present invention can be applied to a liquid crystal display element having a steep threshold characteristic such as a super twist nematic type, and a remarkable effect can be obtained.

[0025]

The dummy substrate is previously rubbed by the same method as the rubbing orientation treatment to age the rubbing material, and the rubbing orientation treatment is applied to the transparent electrode substrate by the aged rubbing material. The direction can be aligned, and the contaminants on the surface of the rubbing material can be removed, the chemical structure on the surface of the rubbing material can be made uniform, and the dust adhering to the rubbing material can be removed. A required rubbing orientation treatment that does not disturb the can be performed. As a result, the alignment state of the liquid crystal molecules becomes uniform, and a liquid crystal display element capable of uniform display without display unevenness can be manufactured with high yield.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a liquid crystal display element manufactured by a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining aging of a rubbing material in one example of the present invention.

[Explanation of symbols]

 1 ... Transparent electrode 2 ... Transparent electrode 3 ... Alignment film 4 ... Alignment film 5 ... Transparent electrode substrate 6 ... Transparent electrode substrate 7 ... Sealant 8 ... Liquid crystal 12 ... Transparent electrode 13 ... Alignment film 14 ... Dummy substrate 15 ... Cylinder 16 ... Rubbing material

Claims (1)

[Claims] 1. A rubbing material is preliminarily aged when the rubbing orientation treatment is performed on the respective facing surfaces of two transparent electrode substrates which are opposed to each other via a liquid crystal with a rubbing material made of cloth, and the aged rubbing material is used. A method for manufacturing a liquid crystal display element, which comprises subjecting the transparent electrode substrate to a rubbing alignment treatment according to.