JPH0363630A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To check the irregularity of color by forming a liquid crystal injection port near a sealing part and providing a liquid crystal introducing path which leads from the liquid crystal injection port to an effective display part outside the effective display part. CONSTITUTION:Flexible polymer film substrates 1 and 2 are provided as a constitution substrate. A sealing material 5 is interposed in a peripheral part and a liquid crystal layer is inserted and held between the substrates. The liquid crystal injection port 6 is formed near the sealing part made of the sealing material 5. The flow of the liquid crystal in the effective display part is checked from the injection port 6 to prevent the movement of a gap material. The liquid crystal introducing path partitioned from the effect display part side by a gap material movement prevention wall 7 communicates between the injection port 6 and the effective display part. By thus providing the liquid crystal introducing path, the movement of the gap material is effectively prevented in the effective display part at the time of injecting the liquid crystal, so that the gap material is uniformly dispersed, a cell gap is uniformized and the irregularity of the color is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device using a flexible polymer film substrate.

[Conventional technology]

In recent years, liquid crystal display devices have become thinner, lighter, easier to process,
From the viewpoint of cost reduction, flexible polymer films such as polyester, polyethylene terephthalate, polyether sulfon, etc. have been widely used as constituent substrates of liquid crystal cells. Generally speaking, a liquid crystal display device using flexible polymer film substrates uses a pair of flexible polymer film substrates that have a transparent electrode formed on one side and an alignment film on the other side. The two substrates are spaced apart so that they face each other, and a sealing material is interposed between the outer peripheries between both substrates to seal them. After the liquid crystal is injected into the interior from the injection port, the injection port is closed with a sealing material (end sealing material). It is made by placing it against soil. As a method for sealing liquid crystal in a liquid crystal cell, for example, as shown in FIG. A common method is to inject the liquid crystal into the cell through the injection port 22 by a method such as vacuum injection, and then seal the injection port 22 with a sealant 23. At this time,
Similarly, as shown in FIG. 4, it is already known technology to provide a protective wall seal 24 near the injection port 22 in the cell so as to be substantially orthogonal to the direction of movement during liquid crystal injection. This is done to prevent the liquid crystal from deteriorating due to the sealing material 23.

On the other hand, the dispersion state of the gap material dispersed between the substrates of the liquid crystal cell is largely related to the display characteristics of the liquid crystal display device. That is, if unevenness occurs in the dispersion state of the gap material, the cell gap changes, resulting in color unevenness, which significantly impairs display quality. In particular, this is a serious problem in STN mode liquid crystal display devices because a slight change in the cell gap causes large color unevenness. Therefore, in order to obtain a liquid crystal display device with a uniform color tone without color unevenness, it is necessary that the gap material is uniformly and evenly dispersed.

[Problem to be solved by the invention]

However, the above conventional liquid crystal display device has the following problems.

Since 1wt pressure injection is used to encapsulate the liquid crystal, the polymer film substrate is deformed due to the pressure difference inside and outside the cell.
Cell bulge occurs. If liquid crystal is injected in this state, the gap material will move due to the flow of liquid crystal, causing cell gap abnormality.

However, although the protective wall seal 24 shown in FIG. 4 is effective in preventing the progression of liquid crystal deterioration (occurrence of twisted domains), it is not sufficiently effective in preventing the gap material from moving as described above. , the gap material in the shaded area in FIG. 4 moves, and the cell gap value decreases, resulting in large color unevenness, especially in STN mode liquid crystal display devices.

The present invention was made in order to solve the problems of the prior art as described above, and it reduces the deformation of the cell during the vacuum injection process, prevents the movement of the gap material due to the flow of liquid crystal,
Even if movement of the gap material occurs, it is stopped only at the introduction path and movement of the gap material in the effective display area is prevented, thereby controlling the cell gap with high precision.
An object of the present invention is to provide a liquid crystal display device with improved display quality.

[Means to solve the problem]

To achieve the above object, according to the present invention, at least one of the constituent substrates is made of a flexible polymer film substrate, and a liquid crystal layer is sandwiched between the substrates by interposing a sealing material around the periphery. A liquid crystal display device characterized in that a liquid crystal injection port is formed in the vicinity of the sealed portion by the sealing material, and a liquid crystal introduction portion that communicates from the liquid crystal injection port to the effective display portion is provided outside the effective display portion. Equipment is provided.

That is, the present invention suppresses the flow of liquid crystal in the effective display area and prevents the gap material from moving by providing a liquid crystal introducing path outside the effective display area.

The liquid crystal introduction path is separated from the effective display section side by a gap material movement prevention wall, and communicates the liquid crystal injection port with the effective display section. The gap material movement prevention wall can be formed using the same material as the material that seals the periphery. It is desirable that the width of the liquid crystal introduction path is at least larger than the width of the liquid crystal injection port in order to prevent bubbles from remaining. Even in this case, since the liquid crystal introducing path is formed near the sealing part, the bulging of the cell is suppressed in the reduced pressure injection process, and the movement of the gap material becomes difficult to occur.

Further, the width of the liquid crystal introducing path may be a constant width.

It is also possible to make it narrowest on the liquid crystal injection port side and widest on the exit side to the effective display area. In this case, there is an advantage that the movement of the gap material can be concentrated near the injection port.

Furthermore, as a means to achieve accurate gap control during liquid crystal injection, in addition to the injection port shape described above, the liquid crystal display side excluding the liquid crystal introduction path is covered with two smooth glass, metal, or plastic plates. It is also possible to inject liquid crystal by sandwiching them together and applying appropriate pressure.

[For production]

By providing the liquid crystal introduction path outside the effective display area, the gap material is effectively prevented from moving in the effective display area when liquid crystal is injected, so the gap material is uniformly dispersed and the cell gap is made uniform. Color unevenness will no longer occur. therefore,
In a liquid crystal display device using a flexible polymer film substrate, it is possible to display a uniform color tone without color unevenness.

〔Example〕

Next, the present invention will be explained in further detail by giving Examples and Comparative Examples.

Example 1 First, a first example will be described with reference to FIG. A polycarbonate film with gas barrier layers laminated on both sides is used as the substrate 1.2. An ITO electric plate with a surface resistance value of 100 Ω/hole is formed on one side of the film, and patterned by a known method to form 100 x 160 dots. form an electrode pattern for the segment electrode 3,
The other electrode was used as a common electrode 4.

Next, an alignment film was formed thereon using a solvent-soluble alignment agent made of polyamide, and rubbed so that the twist angle was 220". Thereafter, the peripheral substrates 1 and 2
so that the extraction electrode can be taken out when pasted together.
The peripheral substrates 1 and 2 were cut into a predetermined shape using a press die. At this time, a round hole injection port 6 with a diameter of 2 cm was simultaneously formed on the common electrode substrate. next.

Plastic beads having a particle size of 6.2 μm were dispersed on the common electrode substrate at a density of 150-200 pieces/lII+12, and a sealing material made of a flexible epoxy adhesive was screen printed on the segment electrode substrate side. At this time, as shown in FIG.
Next, the circumferential substrates 1 and 2 were bonded together with the electrodes 3 and 4 facing each other, and 12
The sealing material was allowed to stand at 0° C. for 60 minutes to harden. After the sealing material had hardened, chiral nematic liquid crystal was injected through the liquid crystal injection port 6 using a reduced pressure injection method, and after the injection, it was sealed with a sealing material made of an epoxy-amine adhesive. Then, a polarizing plate was disposed on the common electrode substrate side, and a polarizing plate with a reflector was disposed on the segment electrode substrate side, thereby obtaining a liquid crystal display panel.

When I observed the color unevenness of the display on this liquid crystal display panel, I found that
The color unevenness caused by the movement of the gap material during liquid crystal injection was only visible in the shaded area in Figure 1.

No color unevenness was observed within the effective display area.

(Example 2) A liquid crystal display panel was obtained in the same manner as in Example 1 except that the seal portion 5 and the gap material movement prevention wall 7 were shaped as shown in FIG.

When we observed the color unevenness of the display on this liquid crystal display panel, we found that the color unevenness caused by the movement of the gap material during liquid crystal injection was only in a part of the shaded area in Figure 2, and the color within the effective display area was similar to the above. No unevenness was observed.

(Comparative example) The gap material movement prevention wall 7 is not provided and the seal portion 5 is
A liquid crystal display panel was obtained in the same manner as in Example 1 except that the shape was as shown in the figure.

In this liquid crystal display panel, color unevenness occurred in the shaded area in FIG. 3, which affected the effective display area.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the liquid crystal injection port is formed near the sealing part, and the liquid crystal introduction path is provided outside the effective display area from the liquid crystal injection port to the effective display area. Deformation of the cell during injection of the liquid crystal is reduced, and movement of the gap material within the effective display area is effectively prevented. Therefore, it is possible to obtain a high-quality flexible plastic film substrate liquid crystal display device with a uniform cell gap and no color unevenness.

[Brief explanation of drawings]

1 and 2 are plan views showing liquid crystal display devices of Example 1 and Example 2 according to the present invention, respectively, FIG. 3 is a plan view showing a liquid crystal display device of a comparative example, and FIG. 4 is a plan view showing a liquid crystal display device of a comparative example. FIG. 1 is a plan view showing an example of the configuration of a display device. 1.2...Flexible polymer film substrate 3...Segment electrode 4...Common electrode 5...Seal part
6...Liquid crystal injection port 7...Gap material movement prevention wall 8...Liquid crystal introduction path

Claims (1)

[Claims] (1) In a liquid crystal display device in which at least one of the constituent substrates is made of a flexible polymer film substrate, and a liquid crystal layer is sandwiched between the substrates with a sealant interposed in the peripheral portion. A liquid crystal display device, characterized in that a liquid crystal injection port is formed in the vicinity of the sealed portion by the sealing material, and a liquid crystal introduction portion that communicates from the liquid crystal injection port to the effective display portion is provided outside the effective display portion.