JPH0247624A - Manufacture of liquid crystal display element - Google Patents

Abstract

PURPOSE:To uniformly and accurately control the cell gap of liquid crystal which uses a plastic film substrate by bringing a member which adsorbs or absorbs liquid crystal into adhering with a liquid crystal injection hole and removing excessive liquid crystal. CONSTITUTION:The absorbing member 6 is brought into contact with the liquid crystal injection hole 4 after a liquid crystal injecting process to absorb the excessive liquid crystal, thereby obtaining a liquid crystal cell 1 whose gap is accurately controlled. A fibrous and porous member such as cloth, paper, and porous plastic is used preferably as the absorbing member 6. When the absorbing member 6 is adhered with the liquid crystal injection hole 4, the liquid crystal cell 1 is slanted preferably at a specific angle theta to a ground plane. Consequently, the liquid crystal cell 1 has no swell, the liquid crystal cell gap is controlled uniformly and accurately through the operation of the surface tension of the liquid crystal and spacers to obtain the liquid crystal display element of high quality which has no color irregularity.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a liquid crystal display element.

[Conventional technology]

In a liquid crystal display element, if the cell gap is non-uniform, color unevenness will appear and the display quality will deteriorate. For this reason, it is extremely important to uniformly control the cell gap during device manufacturing.

Gap control for liquid crystal cells using glass substrates involves applying weight during the substrate bonding process before injecting the liquid crystal, placing spacers to maintain a uniform cell gap, and then injecting the liquid crystal, since the glass substrate is a rigid body. methods are implemented in the production process.

On the other hand, in liquid crystal cells using plastic film substrates, because the plastic film substrate is flexible, even if the cell gap is controlled uniformly when bonding the substrates, the cell gap may be affected by the pressure difference between the inside and outside of the cell when liquid crystal is injected. tends to swell and overfill the liquid crystal. If too much liquid crystal is injected, the cell gap cannot be made sufficiently uniform by the method used for liquid crystal cells. Therefore, after injecting liquid crystal into the liquid crystal cell, use a roller or similar A method of pressing out excess liquid crystal by applying pressure, a method of covering the liquid crystal cell with a heat-shrinkable plastic film, and then heating it (Japanese Patent Application Laid-open No. 183619/1983) have been proposed.

[Problem to be solved by the invention]

However, the prior art has the following problems. When controlling the gap of a liquid crystal cell using a plastic film substrate, if the above-mentioned method of applying pressure with a roller or the like is adopted.

Due to the movement of the spacer placed between the two substrates during pressurization, it is not easy to make the gap uniform over the entire display section with high precision. Additionally, when a method using a heat-shrinkable plastic film is adopted, since the liquid crystal cell itself is flexible, the liquid crystal cell becomes distorted when the heat-shrinkable plastic shrinks, making uniform gap control difficult. be.

The present invention has been made in order to solve the problems of the prior art, and specifically provides a method for manufacturing a liquid crystal display element that can uniformly control the cell gap of a liquid crystal cell using a plastic substrate using an easy method. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the present invention includes a step of assembling a liquid crystal cell by dispersing spacers between a pair of plastic film substrates each having a transparent electrode formed thereon, and interposing a sealing material around the periphery; In a method for manufacturing a liquid crystal display element, which includes a step of injecting liquid crystal into an assembled liquid crystal cell through a liquid crystal injection port, and a step of sealing the liquid crystal injection port after injection of the liquid crystal, after the liquid crystal injection step, the liquid crystal injection port is There is provided a method for manufacturing a liquid crystal display element, comprising a step of controlling a liquid crystal cell gap by bringing a member that adsorbs or absorbs liquid crystal into contact with the liquid crystal and sucking out excess liquid crystal.

As mentioned above, when manufacturing a liquid crystal display element using a plastic film substrate, since the plastic film is flexible, the liquid crystal cell expands due to the pressure difference between the inside and outside of the liquid crystal cell when liquid crystal is injected, causing the liquid crystal to expand. Over-injected. Unless this excess liquid crystal is removed outside the liquid crystal cell, the cell gap cannot be made uniform.Normally, when two substrates are spaced closely apart and a liquid is injected between them, the surface tension of the liquid causes the two substrates to A force that attracts the two acts. When uniformly sized spacers with a narrow particle size distribution are dispersed between the substrates, if the amount of liquid crystal injection is appropriate, the surface tension will cause the gap between the two substrates to match the particle size of the spacer. )' approach to become equal. Therefore, in order to accurately control the cell gap, it is sufficient to remove the excess liquid by some method. Possible methods for removing this liquid include, first, leaving the liquid crystal cell as it is, and suctioning it from the outside with a small force. According to the former method, the excess amount is removed to the outside of the liquid crystal cell by the weight of the liquid crystal. On the other hand, for the latter method, for example,
Excess amount is removed by suctioning under reduced pressure from the liquid crystal injection port. However, in the present invention, from the viewpoint of shortening manufacturing time and simplifying the equipment required for cell gap control, these methods are not used, and a member that adsorbs or absorbs liquid crystal is brought into contact with the liquid crystal injection port to prevent excess liquid crystal. Now removes the liquid crystal. This is similar to the principle of blotting paper.

[For production]

In the present invention, by attaching a member that adsorbs or absorbs liquid crystal to the liquid crystal injection port and sucking out excess liquid crystal, the bulge of the liquid crystal cell is eliminated, and the liquid crystal cell gap is uniformly and precisely adjusted by the surface tension of the liquid crystal and the function of the spacer. Be able to control it better. Therefore, it is possible to provide a high quality liquid crystal display element with no color unevenness.

〔Example〕

A method of manufacturing a liquid crystal display element according to an embodiment of the present invention will be described below.

This embodiment is similar to the conventionally widely used method except for the step of controlling the cell gap of the liquid crystal, so the cell gap control step will be described in detail with reference to FIG. 1.

In Figure 1, ■ is a liquid crystal cell, 2 and 2' are plastic film substrates, 3 is a peripheral sealing material, 4 is a liquid crystal injection port,
5 is a liquid crystal, and 6 is a suction member. Note that illustrations of transparent electrodes, alignment films, spacers, etc. are omitted to simplify the explanation.

When the liquid crystal 5 is injected from the liquid crystal injection port 4 into the liquid crystal cell 1, which is assembled by dispersing spacers between a pair of plastic film substrates 2 and 2' and interposing the outer peripheral sealing material 3, the plastic film substrate 2 , 2' causes the liquid crystal cell 1 to swell as shown by the solid line in FIG. 1(a). Therefore, in this embodiment, after the liquid crystal injection process, Next, the suction member 6 is brought into close contact with the liquid crystal injection port 4, and the excess liquid crystal is sucked out.
A liquid crystal cell 1 whose gap is precisely controlled as shown in FIG. 2(b) is provided. Here, as the suction member 6, it is preferable to use a fibrous or porous member such as a sheet of cloth or porous plastic.After the cell gap is controlled as shown in FIG. The inlet 4 is sealed, and a desired liquid crystal display element is obtained by performing predetermined steps.

In the above, when the suction member 6 is brought into close contact with the liquid crystal injection port 4, it is preferable to tilt the liquid crystal cell l at a predetermined angle θ with respect to the horizontal plane, as shown in FIG.

The size of this angle varies depending on the viscosity of the liquid crystal, the amount of excess liquid crystal, the shape and size of the filling port, etc., but by setting it to an appropriate angle from 0 degrees to 90", the liquid crystal suction speed and the inside of the liquid crystal cell can be adjusted. It is possible to improve defects such as non-uniformity of the gap due to spacer movement. Usually θ is 30 to 60"
It is preferable that

When the above method is applied to the actual production process of liquid crystal display elements, it is necessary to process a large number of liquid crystal cells simultaneously or continuously. For this purpose, as shown in FIG. 3 as an example, a belt-shaped or roller-shaped suction member 1
It is preferable to use 0 and make this member 10 movable. Thereby, a large number of liquid crystal cells can be processed simultaneously or continuously, and productivity can be improved.

Further, the amount of liquid crystal suction by the suction member can be checked by managing the suction time, or by optically measuring changes in transmittance (due to polarized light) of the liquid crystal cell and managing based on the results.

Furthermore, once the absorption member is filled with liquid crystal, it becomes impossible to absorb any more, so as a method to prevent this, the third
As shown in 11 in the figure, it is also possible to use a blade to remove the sucked liquid crystal from the suction member. Alternatively, a groove may be formed in the blade 11 to collect and collect the removed liquid crystal.

[Effects of the Invention] As described in detail above, according to the present invention, excess liquid crystal is removed by bringing a member that adsorbs or absorbs liquid crystal into contact with the liquid crystal injection port, so that it is particularly effective for plastic film substrates. The cell gap of the liquid crystal used can be controlled uniformly and accurately, making it possible to provide a high-quality liquid crystal display element.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the cell gap control process according to the embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the liquid crystal cell and the horizontal plane when excessive liquid crystal is sucked, and FIG. FIG. 2 is an explanatory diagram of a method of processing simultaneously or sequentially. 1...Liquid crystal cell 2, 2'...Plastic film substrate 3...Peripheral sealing material 5...Liquid crystal 11...Blade 4...Liquid crystal injection port 6.10...Suction member

Claims (1)

[Claims] (1) The process of assembling a liquid crystal cell by dispersing spacers between a pair of plastic film substrates on which transparent electrodes are formed and interposing a sealing material around the periphery, and placing liquid crystal in the assembled liquid crystal cell. A method for manufacturing a liquid crystal display element comprising a step of injecting liquid crystal from an inlet and a step of sealing the liquid crystal inlet after injecting the liquid crystal, the method comprising: contacting a member that adsorbs or absorbs liquid crystal to the liquid crystal inlet after the liquid crystal injection step; A method for manufacturing a liquid crystal display element, comprising a step of controlling a liquid crystal cell gap by sucking out excess liquid crystal.