JPH0627471A - Production of liquid crystal panel - Google Patents

Abstract

PURPOSE:To decrease an investment amt. and to enable uniform orientation by sticking rubbed substrates opposite to each other while maintaining a spacing therebetween and packing a specific liquid crystal into this spacing to obtain a liquid crystal cell, then maintaining the liquid crystal cell at a specific temp. and impressing parallel static magnetic fields thereto. CONSTITUTION:The substrates 1a, 1b subjected to an orientation treatment are stuck to each other while maintaining the spacing therebetween in such a manner that the transparent electrodes (ITO) thereof face each other, by which the empty cell is obtd. The liquid crystal exhibiting a chiral smectic C phase at ordinary temp. is packed into the spacing between the substrates 1 and the substrates are sealed. The liquid crystal cell packed with the liquid crystal is heated, by which the liquid crystal is maintained at the smectic A phase and are exposed to parallel static magnetic lines of force. The direction of the magnetic lines of force is approximately within the substrates 1 and are preferably in the direction of the rubbing; more preferably, this direction is in the direction of rubbing and is provided with some angle (within several with the substrate 1 surface. The layer structure is by which the zigzag defects are decreased and the contrast is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of aligning liquid crystal molecules and a method of manufacturing a liquid crystal panel used in a liquid crystal display device or the like.

[0002]

2. Description of the Related Art FIG. 1 is a sectional view of a general liquid crystal panel. Substrates 1a, 1 on which transparent electrodes (ITO) 10 are formed
The liquid crystal 5 is sealed by the sealing material 3 between b. The substrates 1a and 1b are kept at a constant interval by a spacer 11 and generally have a thickness of 5 to 10 μm. The spacers 11 are white ones such as polystyrene resin balls (for example, Micropearl (manufactured by Sekisui Chemical Co., Ltd.)). Reference numeral 2 is an alignment film.

Conventionally, as a method of orienting the molecules of the liquid crystal, a film of polyimide or the like is applied on a substrate by a printing method,
Then, it is cured by heat to form a film, and the film is rubbed (rubbed) in a predetermined direction with a cloth or the like, and then the chiral smectic C liquid crystal is brought into contact with the alignment film to align the liquid crystal molecules. I am letting you.

Alternatively, there is also a method of using a substrate on which silicon oxide (SiO) is obliquely vapor-deposited (that is, oblique vapor-deposition), and bringing a liquid crystal into contact therewith to orient the molecules.

Regarding the method of aligning these liquid crystal molecules,
"Liquid Crystal Device Handbook", Japan Society for the Promotion of Science, 14th
It is introduced in detail in 2 committee editions and Nikkan Kogyo Shimbun.

[0006]

However, in the above-mentioned oblique vapor deposition method, a large amount of investment is required for the apparatus such as using a vacuum, and the orientation processing speed is difficult.

Further, in the method of obtaining an alignment film by rubbing the above-mentioned polyimide film or the like, uniform alignment is difficult, and as a result, for example, in the display of a liquid crystal display device, display defects due to the non-uniform alignment are considerable. There is a problem that it occurs with a defective rate.

That is, for example, in the chiral smectic C phase, the liquid crystal molecules have a layered structure. Therefore, according to these conventional alignment methods, the surface-stabilized ferroelectric liquid crystal (SSF) using the chiral smectic C phase is used.
In LC) panels, the layers are often disordered,
This adversely affects the optical characteristics of the liquid crystal panel.

In view of such problems of the conventional liquid crystal molecule alignment method, the present invention provides a method of manufacturing a liquid crystal panel which does not require a large investment amount, has an excellent alignment treatment speed, and is capable of uniform alignment. It is intended.

[0010]

According to the present invention, liquid crystals exhibiting a chiral smectic C phase are made by adhering main surfaces of a substrate coated with a rubbed film to each other with a desired gap kept therebetween. Is provided to obtain a liquid crystal cell, and the liquid crystal cell is further maintained at a temperature exhibiting a smectic A phase, and a parallel static magnetic field is applied to the liquid crystal panel.

The present invention is also a method for producing a liquid crystal panel, wherein the film is made of an organic material or an inorganic material.

Further, the present invention is a method for producing a liquid crystal panel, wherein the direction of application of the static magnetic field is the direction of rubbing and the angle formed with the substrate surface is slight (within several degrees).

[0013]

In the present invention, in a surface-stabilized ferroelectric liquid crystal panel using a chiral smectic C phase, layer disturbance is caused by heating the liquid crystal cell to a smectic A phase and applying a parallel static magnetic field. By doing so, it seems that it has been minimized. This improves the alignment of the liquid crystal. Here, the smectic A phase has a layered structure, but the liquid crystal molecules do not have a helical structure, and although they are disturbed, they locally face in the same spatial direction. Therefore, the liquid crystal molecules are globally regulated in the same direction by the static magnetic field, and thereby the disturbance of the layer structure is minimized.

The effect of the static magnetic field is large when the application direction of the static magnetic field is the rubbing direction and the angle with the substrate surface is slight (within several degrees).

[0015]

EXAMPLES Examples of the present invention will be described below.

A plurality of stripe-shaped transparent electrodes (ITO)
4 substrates having A polyparabanic acid resin (solvent NMP, normal methyl 2pyrrolidone) manufactured by Tonen Kagaku Co., Ltd. was applied to this with a spinner, and then,
The solvent was evaporated.

The rubbing treatment for the film is rayon.
Made with buff. In this way, the two substrates that had been subjected to the orientation treatment were adhered to each other with the gap of about 1.5 μm being maintained so that the ITO faces each other to obtain an empty cell. Two types of empty cells were produced, one in which the rubbing directions of the upper and lower substrates were parallel and one in which they were anti-parallel.

Next, a liquid crystal showing a chiral smectic C phase at room temperature was filled in the gap between the substrates and sealed. In the filling operation, it is easier to reduce the viscosity of the liquid crystal, and it is usually heated to make an isotropic liquid phase. Of course, the empty cell is also heated when the liquid crystal is filled. It should be noted that most liquid crystals exhibiting a chiral smectic C phase have a smectic A phase state in a higher temperature region. Of course, this used liquid crystal also applies to this example.

Next, the liquid crystal cell filled with the liquid crystal is heated to keep the liquid crystal in the smectic A phase, and the liquid crystal cell is kept in parallel with the liquid crystal cell for about 3 minutes.
It was exposed to a static magnetic field line of 0 kilogauss for about 3 minutes. It is desirable that the direction of the lines of magnetic force is generally in the substrate and in the rubbing direction. Particularly preferably, this direction is the rubbing direction, and the angle formed with the substrate surface is preferably slightly (within several degrees) the result is preferable.

Observation of such a liquid crystal panel revealed that the layer structure was well-ordered and zigzag defects were few. The display contrast was also improved by about 30%. this is,
It is considered that this is due to the improvement of the orientation of the liquid crystal.

The alignment film of the present invention may be made of an inorganic material.

Needless to say, the application of the parallel static magnetic field of the present invention is not limited to the magnitude and direction described in the above embodiment.

[0023]

As is apparent from the above description,
In the present invention, at least one of the substrates coated with an organic substance or an inorganic substance, which has been rubbed, is made to face the main faces thereof, and is bonded with a desired gap therebetween, and the gap is filled with a liquid crystal showing a chiral smectic C phase. Then, the liquid crystal cell is obtained, and the liquid crystal cell is kept at a temperature showing the smectic A phase and a parallel static magnetic field is applied. Therefore, the investment amount is not large, the alignment treatment speed is excellent, and uniform alignment is possible. It is possible to provide a method for manufacturing a liquid crystal panel.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a general liquid crystal panel.

[Explanation of symbols]

 1 Substrate 1a, 1b Upper and lower substrates 2 Alignment film 3 Sealing material 5 Liquid crystal 10 Transparent electrode (ITO) 11 Spacer

Claims (3)

[Claims] 1. A liquid crystal in which at least one surface of a substrate coated with a film rubbed is opposed to each other, and the substrates are bonded together with a desired gap therebetween, and this gap is filled with a liquid crystal showing a chiral smectic C phase. A method for producing a liquid crystal panel, characterized in that the cell is obtained, and the liquid crystal cell is kept at a temperature showing a smectic A phase, and a parallel static magnetic field is applied. 2. The method for producing a liquid crystal panel according to claim 1, wherein the film is made of an organic material or an inorganic material. 3. A static magnetic field is applied in the rubbing direction and at a slight angle (within a few degrees) with the substrate surface.
The method for producing a liquid crystal panel according to claim 1, wherein