JPS6391630A - Formation of oriented film in liquid crystal cell - Google Patents

Abstract

PURPOSE:To eliminate need for rubbing and to facilitate patterning so as to simplify stages and to improve production efficiency by using a photosetting resin as an orienting agent soln. and fixing the orientation by projecting light thereto after formation of the orientation. CONSTITUTION:The photosetting resin is used as the orienting agent soln. and the orientation is fixed by projecting the light thereto after the formation of the orientation. For example, a substrate 104 is immersed into a treating liquid tank 100 in such a manner that the greater part thereof sinks in the orienting agent soln. 102 and is held in this state for 10min. The substrate 104 is then pulled upward in a vertical direction at 20mm/sec pulling-up speed. A light shielding plate 108 is so disposed as to parallel with the projection face of the substrate in the stage when the pulling-up and the drying of the solvent end. The light from an extremely high pressure mercury lamp 110 is projected in such a state to the oriented film 104a of the substrate through the light shielding plate 108 from the direction perpendicular to the plane of the plate 108. The oriented film 104a stuck with a photosensitive polyimide resin is then cured and the molecular arrangement in the vertical direction is fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of forming an alignment film on a substrate of a liquid crystal cell, and more particularly to a method of forming an alignment film by immersing a substrate in an alignment agent.

[Conventional technology]

There are various methods for forming an alignment film on the substrate of a liquid crystal cell, including letterpress printing, screen printing, spinner coating,
A method is used in which the material is attached to a substrate by a dipping method or the like and then oriented by rubbing.

On the other hand, in recent years, consideration has been given to applying large, curved liquid crystal cells to automobile roofs, windshields, etc., and using them as light control elements.

However, when forming an alignment film on the substrate of these liquid crystal cells, it is difficult to perform a rubbing treatment because the substrate has a curved surface (Japanese Patent Laid-Open No. 60-250331). That is, it is difficult to uniformly form an alignment film with a certain depth on a large or curved substrate.

In contrast, as shown in FIG. 6, by filling the processing liquid tank 202 with a polyimide resin solution 200 and pulling up the substrate 204 in the vertical direction, the molecules are arranged in parallel in the pulling direction (direction of arrow A in the figure). It is being considered to provide orientation without rubbing.

[Problem that the invention seeks to solve]

However, after the polyimide resin solution adheres to the substrate, 3
It was necessary to dry at a temperature of about 0.000C, and during this time the molecular arrangement of the alignment agent was disturbed, resulting in a decrease in alignment performance.

Further, the alignment film needs to be formed excluding the area to which adhesive is applied for fixing and sealing the periphery of the pair of substrates. To solve this problem, conventionally, a masking agent is applied to the adhesive-applied portion of the substrate, and after masking, an alignment film is formed.

However, there was a problem in that the process of attaching the masking agent to the substrate was complicated and required a lot of manufacturing time. Furthermore, due to the presence of the masking agent, the alignment agent around the masking agent is disturbed and adheres to the masking agent, causing problems such as uneven alignment.

Therefore, an object of the present invention is to provide a method for forming an alignment film in a liquid crystal cell, which maintains high alignment performance even in large or curved liquid crystal cells, and improves production efficiency by simplifying the process. .

[Means for solving problems]

Therefore, the method for forming an alignment film for a liquid crystal cell according to the present invention is characterized in that a photocurable resin is used as an alignment agent solution, and after alignment is formed, the alignment is fixed by irradiation with light.

Specifically, the configuration of the present invention is as follows.

The explanation will be given based on the configuration explanatory diagram of FIG. 1, using reference numerals.

This is a method in which an alignment film is formed on the side of the substrates in contact with the liquid crystal of a liquid crystal cell, which is constructed by sealing liquid crystal in a space formed using a pair of opposing substrates as outer shells.

The substrate (30) is immersed in a treatment liquid tank (20) containing an alignment agent solution (10) in which a photocurable resin is dissolved.
After attaching the alignment agent to the substrate (30), the substrate (30) is pulled up from the treatment liquid tank (20) and irradiated with light.
An alignment film (40) is formed on the substrate (3o).

In the configuration of the present invention described above, the alignment agent solution may be a solution in which a photosensitive polyimide resin or the like is dissolved in a solvent such as N-methyl-2-pyrrolidone or methyl cellosolve.

Further, an electrode film for applying an electric field or supplying electricity for driving the liquid crystal is formed on the substrate (30), but when forming the electrode film inside the substrate (3o) constituting the outer shell, the electrode film is formed in advance. After the formation, an alignment film is formed. When forming an electrode film on the outside of the shell, the order does not matter.

[Effect]

According to the above-described method for forming an alignment film in a liquid crystal cell of the present invention, a photocurable resin is used as an alignment agent solution, and after alignment is formed, light is irradiated to fix the alignment.
Since the alignment of the alignment agent resin is fixed without being disturbed by light irradiation when the substrate is pulled up, rubbing is not necessary and the alignment is orderly.

Further, if the alignment film covers unnecessary areas during light irradiation, patterning can be easily performed without attaching a masking agent to the substrate.

〔Example〕

Next, an example of a method for forming an alignment film in a liquid crystal cell according to the present invention will be described in order based on the drawings.

2 to 5 are drawings for explaining a method of forming an alignment film in a liquid crystal cell according to the present invention.

FIG. 2 is a diagram showing a state in which the substrate is immersed, and is a schematic cross-sectional view of the processing liquid tank. FIG. 3 is a cross-sectional view of the same showing a state in which the substrate is pulled up. FIG. This cross-sectional view shows the state in which the agent is cured, and FIG. 5 is a drawing taken in the direction of the arrow ``■'' in FIG. 4.

In FIG. 2, reference numeral 100 is a box-shaped processing liquid tank. The treatment liquid tank 100 is filled with an alignment agent solution 102 .

The processing tank 102 has a width x depth x depth of 15.
It is made of stainless steel and has a size of 0x30x100 cm, and contains 4001 pieces of alignment agent solution 102. The alignment agent solution 102 is a photosensitive polyimide resin (“
Photonice") dissolved in a solvent of N-methyl-2-pyrrolidone was used. The concentration of the alignment agent solution 102 was 184%, and the nonvolatile matter in the alignment agent solution 102 was 3%.

The substrate 104 is immersed in the treatment liquid tank 100 so that most of the substrate is submerged in the alignment agent solution 102.
The state was held for 0 minutes. Then, the substrate 104 is
It was pulled upward in the vertical direction at a pulling speed of 0*x/sec. Then, the alignment agent solution 104 adheres to the surface of the substrate 104 and is dragged upward, forming the alignment films 104a and 104b.
(state shown in FIG. 3). The substrate used was a rectangular one with a thickness of 2 mm and a size of 500 x 1000 m. A transparent electrode film made of TTO (solid solution of indium oxide and tin oxide) is formed on this substrate 104 to a thickness of 200 mm.

This substrate 104 constitutes a liquid crystal cell for a moonroof after the alignment film is formed.

As shown in FIG. 3, the substrate 104 was pulled up and exposed to hot air at 80° C. for 10 minutes from a hot air blower 106 to remove the solvent of the alignment agent solution 102 adhering to both surfaces of the substrate 104. In this state, the photosensitive polyimide resin is adhered to both sides of the substrate 104 due to the vertical molecular arrangement produced when the substrate 104 is pulled up in the vertical direction. After the drying of the solvent is completed, the light shielding plate 108 is placed parallel to the projection plane of the substrate. This light-shielding plate 108 is made of black-painted iron and consists of a light-shielding part 108a of the adhesive-applied part of the substrate work 02 and a light-transmitting part 108b to the alignment film forming part (as shown in FIG. 5).

In this state, the alignment film 104a of the substrate 104 was irradiated with light from the ultra-high pressure mercury lamp 110 in a direction perpendicular to the surface of the light shielding plate 108 through the light shielding plate 108. Then,
The alignment film 104a to which the photosensitive polyimide resin is attached is cured, and the molecular arrangement in the vertical direction (direction of arrow B in the figure) is fixed.

After sono, base! &104 was immersed in isopropyl alcohol and subjected to ultrasonic cleaning to remove uncured portions of the alignment films 104a and 104b.

As a result of the above, the alignment film 10 is arranged parallel to the substrate in a constant direction with an appropriate film thickness of 400±50 nm.
4a was obtained. A set of substrates 104 on which this alignment film 104a was formed was used to form the outer shell of a liquid crystal cell, and a guest-host type liquid crystal (manufactured by Merck & Co., Ltd., ZLI-1841) was sealed in the space. ,
An automobile moonroof was fabricated as a light control element.

When we investigated the alignment state of liquid crystal molecules in this moonroof, we obtained good results with no response unevenness, reverse tilt, etc., and the performance was higher than that of the conventional alignment film that was pulled up using a polyimide resin solution. It was found that the film had good alignment performance that could be used as a moon roof. Furthermore, in the manufacturing process, masking and rubbing steps are not required, resulting in a significant reduction in manufacturing time. Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. .

〔Effect of the invention〕

As described above, according to the method for forming an alignment film in a liquid crystal cell of the present invention, rubbing is not necessary and patterning is easy, so the process is simplified and production efficiency is improved.

Furthermore, since the arrangement of the resin is fixed without being disturbed by light irradiation, the arrangement is orderly and the alignment performance is high.

Another advantage is that fixing the alignment film does not require high-temperature heat treatment, and a resin that is weak against heat can be used as the substrate.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of the present invention. 2 to 5 are drawings for explaining a method of forming an alignment film in a liquid crystal cell according to the present invention. FIG. 2 is a drawing showing a state in which the substrate is immersed, and is a schematic cross-sectional view of the processing liquid tank. FIG. 3 is a sectional view of the same showing a state in which the substrate is pulled up. FIG. 4 is a cross-sectional view showing a state in which the alignment agent is cured by irradiating light. FIG. 5 is a drawing taken in the direction of the arrow ``■'' in FIG. 4. FIG. 6 is a schematic diagram for explaining a conventional alignment film forming method. 10.--Alignment agent solution 20--Processing liquid tank 3 (1--------1 substrate 40--Alignment film applicant Toyota Motor Corporation 10.--1) Foaming row Kotobuki 2o-11 double-sided tank 3G-board 40---Ippakuba P3 picture 1

Claims (1)

[Claims] When forming an alignment film on the side of the substrate in contact with the liquid crystal of a liquid crystal cell, which is constructed by sealing a liquid crystal in a space formed with a pair of facing substrates as outer shells, an alignment agent solution containing a photocurable resin dissolved therein is stored. A liquid crystal that forms an alignment film on the substrate by immersing the substrate in a treatment liquid bath to make an alignment agent adhere to the substrate, then pulling the substrate out of the treatment liquid bath and irradiating it with light. A method for forming an alignment film in a cell.