JPH05241155A - Rubbing cloth for orienting liquid crystal molecule and production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To develop the rubbing cloth for optimum orientation of liquid crystal molecules, from which the liquid crystal display element exhibiting a uniform display state free from display defects, such as rubbing flaws. CONSTITUTION:The surface of the high-polymer resin film of an oriented film is subjected to a rubbing orientation treatment by using the rubbing cloth 16 formed by drying the rubbing cloth 11 immersed into a coating material 13 consisting essentially of silicone on a heater plate 15 and subjecting the textile fibers on the surface to a heat resistant treatment. Two sheets of the substrates treated in such a manner are stuck to each other via a spacer in such a manner that the surfaces of the oriented films face each other, by which the liquid crystal display element is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubbing cloth for aligning liquid crystal molecules, which is used in manufacturing a liquid crystal alignment film for aligning liquid crystal molecules, and a method for manufacturing a liquid crystal display device manufactured by using the rubbing cloth. is there.

[0002]

2. Description of the Related Art Generally, in a liquid crystal display device, a transparent electrode layer made of indium tin oxide (hereinafter abbreviated as ITO) is formed on a glass substrate and then a polymer resin such as polyimide is formed on the transparent electrode layer. A liquid crystal alignment film is formed, and then the liquid crystal alignment film is rubbed (rubbed) in a specific direction by using a roller around which a rubbing cloth made of organic fibers is wound, and the liquid crystal alignment film is opposed to the liquid crystal alignment film. The method of encapsulation is used.

[0003]

However, in such a rubbing treatment method, when rubbing the polymer resin film with the textile fiber,
When a considerable amount of heat is locally generated, the fibers in the frictional portion are gradually damaged, causing a change in shape and the like, and eventually the normal rubbing orientation treatment may not be performed. As a result, there is a problem that rubbing scratches and rubbing lines are generated and display quality is impaired.

Further, when a rubbing treatment is applied to a polymer resin film which has been heated to a temperature around the glass transition point in advance,
Since the polymer chains are in an unstable state, alignment treatment can be performed under weak rubbing conditions. Accordingly, the generation of frictional heat is reduced by doing so, however, in this type of rubbing orientation treatment, not only the polymer resin film but also the rubbing cloth is heated at the same time, and the same deterioration as described above occurs.

Therefore, it has been difficult for the conventional rubbing cloth to achieve uniform orientation for a long period of time.

In view of the problems of the conventional rubbing cloth, it is an object of the present invention to provide a rubbing cloth for aligning liquid crystal molecules which is excellent in heat resistance and a method for manufacturing a liquid crystal display device using the rubbing cloth. To do.

[0007]

The present invention is a rubbing cloth for aligning liquid crystal molecules, wherein the surface of the textile fiber of the rubbing cloth for aligning liquid crystal molecules is heat-treated.

Further, according to the present invention, the material for heat-treating the textile fiber is a rubbing cloth for aligning liquid crystal molecules, which is a coating material containing silicone as a main component.

Further, according to the present invention, when a polymer resin film provided on a liquid crystal support plate having a transparent electrode layer is subjected to a rubbing orientation treatment, the surface of the textile fiber in contact with the polymer resin film contains silicone as a main component. Is a method for manufacturing a liquid crystal display element, in which a rubbing alignment treatment is performed using a rubbing cloth heat-treated with the coating material.

[0010]

In the present invention, the heat resistance of the surface of the rubbing cloth is improved by coating the surface of the textile fiber forming the rubbing cloth with a paint such as varnish containing silicone as a main component. Therefore, by using the rubbing cloth treated in this way, the durability is remarkably improved as compared with the conventional rubbing cloth which is not heat-resistant treated.

[0011]

EXAMPLES A method for manufacturing a rubbing cloth for aligning liquid crystal molecules and a method for manufacturing a liquid crystal display device according to examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a process of processing a rubbing cloth for aligning liquid crystal molecules according to the present invention. As shown in FIG. 1 (a), a rubbing cloth 11 is coated with a solvent 13 containing a silicone varnish.
Immerse in a certain time. Then, as shown in FIG. 1B, the rubbing cloth 11 is pulled up and the heater plate 15 is pulled up.
The above is dried at a constant temperature and a constant time.

The rubbing alignment treatment is carried out by rubbing the surface of the liquid crystal alignment film of a polymer resin provided on the glass substrate having the ITO electrode layer, using the rubbing cloth 11 which has been heat-treated as described above.

FIG. 2 is a sectional view showing the structure of a liquid crystal display element manufactured by using the alignment film 23 made of the polymer resin film which has been subjected to the alignment treatment as described above. A transparent electrode layer (ITO layer) 22 is formed on a substrate 21 made of glass, plastic or the like, a polymer resin film is formed on the transparent electrode layer 22, and then an alignment film 23 is formed by an alignment treatment with a rubbing cloth having the above characteristics.
Two liquid crystal support plates 25 having the above are prepared, the spacer / sealing resin 24 is printed on one of the support plates 25, and the two liquid crystal support plates 25 are attached so that the alignment films 23 face each other, and the opening portion is formed. More nematic liquid crystal was injected. Then, the opening was sealed and a liquid crystal display element was produced. Subsequently, the liquid crystal was heated to a temperature at which it was isotropic, annealed at that temperature for 1 hour, and then slowly cooled to complete a liquid crystal display element.

Next, this embodiment will be described more specifically.

Example 1 A silicone varnish was diluted with trichloroethane to prepare a treating agent having a silicone component of 1.5 wt%. A rubbing cloth 11 made of rayon is dipped in this treatment agent as shown in FIG. 1 (a), and then the rubbing cloth is placed on the heater plate 15 which is set to a constant temperature in advance as shown in FIG. 1 (b). 16 were dried.
The drying conditions are 140 ° C. and 2 minutes.

Next, as shown in FIG. 3, the glass substrate 32 on which the pattern of the transparent electrode layer (ITO layer) 33 is formed by using the roller 35 around which the rubbing cloth 36 subjected to the heat resistance treatment is wound.
The surface of the polyimide-based alignment film 34 provided above was rubbed four times in the same direction and subjected to rubbing treatment to complete the alignment film for liquid crystal. This rubbing treatment step was continuously performed using the same rubbing cloth 36 to obtain 150 alignment films for liquid crystals. Reference numeral 31 is a rubbing stage.

A liquid crystal display device was manufactured by the following method using a pair of liquid crystal support plates each having a polyimide liquid crystal alignment film formed by the above treatment. Therefore, the number of completed liquid crystal display elements is 75. FIG. 4 is a diagram showing the configuration of the liquid crystal display element. Glass fibers having a diameter of 6.0 μm are used as the spacer / sealing resin 45 on the surface of one support plate (for example, the lower liquid crystal support plate 42) on which the alignment film is formed. After printing the dispersed acid anhydride-curable epoxy resin on only one side with a width of 5 mm left in the center of the side and 0.2 mm width on the other periphery,
Pressure was applied in a state where the rubbing directions 43 and 44 of the alignment films formed on the upper liquid crystal support plate 41 and the lower liquid crystal support plate 42 were parallel to each other and the surfaces of the alignment films were opposed to each other, and heating and bonding were performed at 140 ° C. for 4 hours. After the adhesion, nematic liquid crystal (manufactured by Merck & Co., product name ZLI-2293) was injected by vacuum injection, and after injection, the opening 46 was sealed with a commercially available acid anhydride-curable epoxy resin. After sealing, the liquid crystal was heated to a temperature at which the liquid crystal was isotropic, annealed at that temperature for 1 hour, and then slowly cooled to complete a liquid crystal display element.

The liquid crystal display element completed in this way has 75
All the sheets showed a uniform display state with almost no rubbing scratches or rubbing lines.

(Comparative Example 1) As shown in FIG. 5, a roller 55 around which a rubbing cloth 51 made of the same rayon as that of Example 1 not subjected to heat resistance treatment is wound is used to form a transparent electrode layer (ITO layer) 53. Patterned glass substrate 52
The surface of the polyimide-based alignment film 54 provided above was rubbed four times in the same direction and subjected to rubbing treatment to complete the alignment film for liquid crystal. This rubbing process step was continuously performed using the same rubbing cloth 51 to obtain 150 alignment films for liquid crystals.
In the liquid crystal display device manufactured by the same operation as in Example 1 below, the liquid crystal display device in which a uniform display state was obtained was 45 panels out of 75 panels.

The rubbing cloth for aligning liquid crystal molecules is not limited to the rayon shown in the above embodiment, and various textile fibers such as nylon, cellulose and polyester can be used.

Further, the polymer resin film is not limited to the above-mentioned polyimide, but can be used for various synthetic polymer films such as polyamide and polyvinyl alcohol, as well as natural polymer films such as polypeptides and proteins.

The heat treatment of the rubbing cloth of the present invention is
The heat treatment is not limited to the above-mentioned treatment with silicone, and may be another heat treatment.

[0024]

As is clear from the above description,
The present invention, since the surface of the textile fiber of the rubbing cloth for aligning liquid crystal molecules is heat-treated, when a liquid crystal display device is manufactured using the rubbing cloth, it shows a uniform display state without display defects such as rubbing lines. It has an advantage that a liquid crystal display device can be manufactured for a long period of time.

[Brief description of drawings]

FIG. 1 is a diagram showing a heat-resistant treatment process of a rubbing cloth for aligning liquid crystal molecules of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a liquid crystal display element produced by using a polymer resin coating film subjected to rubbing alignment treatment using the rubbing cloth for aligning liquid crystal molecules of the present invention.

FIG. 3 is a diagram showing a step of rubbing a polymer resin film using the rubbing cloth for aligning liquid crystal molecules of the present invention.

FIG. 4 is a diagram showing a configuration of a liquid crystal display device manufactured by using a polymer resin coating film subjected to rubbing alignment treatment using the rubbing cloth for aligning liquid crystal molecules of the present invention.

FIG. 5 is a diagram showing a process of rubbing a polymer resin film using a rubbing cloth for aligning liquid crystal molecules, for explaining a comparative example.

[Explanation of symbols]

 11 rubbing cloth 12 rubbing cloth support rod 13 heat-resistant treatment agent 14 rubbing cloth treatment tank 15 heater plate 16 rubbing cloth heat-treated 21 substrate 22 transparent electrode layer 23 alignment film 24 spacer / seal resin 25 liquid crystal support plate 31 rubbing stage 32 glass Substrate 33 Transparent electrode layer 34 Alignment film 35 Rubbing roller 36 Heat-resistant rubbing cloth 41 Upper liquid crystal support plate 42 Lower liquid crystal support plate 43 Rubbing treatment direction of upper liquid crystal support plate 44 Rubbing treatment direction of lower liquid crystal support plate 45 Spacer Sealing resin 46 Opening 51 Rubbing stage 52 Glass substrate 53 Transparent electrode layer 54 Alignment film 55 Rubbing roller 56 Rubbing cloth

Claims (3)

[Claims] 1. A rubbing cloth for aligning liquid crystal molecules, wherein the surface of the textile fiber of the rubbing cloth for aligning liquid crystal molecules is heat-treated. 2. The rubbing cloth for aligning liquid crystal molecules according to claim 1, wherein the material for heat-treating the textile fiber is a coating material containing silicone as a main component. 3. When a polymer resin film provided on a liquid crystal support plate having a transparent electrode layer is subjected to a rubbing orientation treatment, the surface of the textile fiber in contact with the polymer resin film is coated with a silicone-based paint. A method for producing a liquid crystal display element, comprising subjecting a liquid crystal display element to a rubbing orientation treatment using a rubbing cloth that has been heat-treated.