JPH05323334A - Method and device for injecting liquid crystal - Google Patents

Abstract

PURPOSE:To considerably shorten the time required to inject a liq. crystal material into panels by a vacuum injecting method. CONSTITUTION:Liq. crystal panels 5 each having plural injection holes 3 in two or more sides are horizontally disposed in a vacuum vessel, this vessel is evacuated and a liq. crystal 6 is dropped into the injection holes 3 from liq. crystal feeding nozzles 7. The internal pressure of the vacuum vessel is then slowly returned to atmospheric pressure and the liq. crystal is filled into the liq. crystal panels 5 by the pressure difference between the insides and outsides of the panels 5. The time required to seal the liq. crystal in the liq. crystal panels can be considerably shortened as compared with the conventional time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal injecting method and a liquid crystal injecting apparatus used for injecting liquid crystal into a liquid crystal cell in a process of manufacturing a liquid crystal display element.

[0002]

2. Description of the Related Art With the development of liquid crystal display technology, the panel size is increasing and the display is becoming higher definition. Currently, the biggest problem is cost reduction, and efforts are being actively made to reduce material costs such as color filters and polarizing plates, improve yield, and improve throughput.

In particular, the liquid crystal injection time has become longer and longer with the increase in panel size, which is a major factor in inhibiting productivity. The injection method widely adopted at present is a so-called reduced pressure injection method (also referred to as a vacuum injection method). FIG. 3 is a perspective view in a vacuum container of a conventional reduced pressure injection method. Injection port 3 of liquid crystal panel 5 under reduced pressure in a vacuum container
After making contact with the liquid crystal 5 filled in the liquid crystal reservoir 8, air, nitrogen gas, or argon gas is introduced into the vacuum container to seal the liquid crystal by the pressure difference between the inside and outside of the panel.

[0004]

SUMMARY OF THE INVENTION This method has a size of 1 inch.
A small panel of about 4 inches does not cause much problem, but a large-sized panel of 10 inches or more requires a long injection time of several hours, which has become a serious process problem.

To address this problem, efforts have been made (1) improving the vacuum degree in the injection tank, improving the vacuum injection device such as increasing the vacuum pump displacement, and (2) developing a multi-point dropping process. ing.

However, there is a problem in that a high degree of vacuum in the filling tank and an increase in the exhaust amount of the vacuum pump cause a change in the liquid crystal composition due to the evaporation of the liquid crystal material, which causes a deterioration in display quality.

On the other hand, the liquid crystal encapsulation process by the dropping process is a method of dropping a liquid crystal material on the surface of the alignment film and then bonding two substrates together to form a panel. There is a problem that highly precise control of the dropping amount is required and that the orientation is centered around the dropping point and leads to non-uniformity.

As a solution in terms of panel design, it is considered that the number of inlets should be increased. However, in order to bring the inlets of a plurality of panels into contact with the liquid crystal in the liquid crystal reservoir installed in the vacuum container, the panels must be installed upright as shown in FIG. Therefore, it is difficult to provide the injection port on multiple sides of the panel. Further, after the liquid crystal is injected, a large amount of liquid crystal remains in the liquid crystal reservoir, and when the liquid injection is repeated, the liquid crystal in the liquid crystal reservoir is injected as it is or by further adding the liquid crystal. as a result,
There are problems such as fluctuation of liquid crystal composition due to reduced pressure and contamination of liquid crystal by impurities.

[0009]

When injecting a liquid crystal material into a panel, a panel not filled with liquid crystal having a plurality of injection ports on at least two sides is placed horizontally in a vacuum container, and the injection is performed. A predetermined amount of defoamed liquid crystal is supplied to the inlet from a nozzle, and then the liquid crystal is injected by returning the pressure in the vacuum container to normal pressure.

A shelf for horizontally holding a plurality of liquid crystal panels is provided in a vacuum container, and a movable nozzle for supplying liquid crystal is provided at an inlet of each panel.

[0011]

[Function] Although the injection time of the liquid crystal material largely depends on the panel gap, the panel size, and the injection port size, the panel gap is a design item of the panel and is largely related to the optical characteristics. However, this is due to the user's request and cannot be arbitrarily changed only from the viewpoint of the injection time.

According to the present invention, by providing a plurality of injection ports on a plurality of sides of the liquid crystal panel, it is possible to raise the degree of vacuum in the panel in a short time and shorten the time for injecting the liquid crystal into the panel. .. Furthermore, by supplying a necessary amount of liquid crystal to the inlet, the amount of liquid crystal that was conventionally left in the liquid crystal reservoir and was discarded can be suppressed, and the liquid crystal material is no longer exposed to reduced pressure for a long time. It is also possible to prevent composition fluctuations and contamination.

[0013]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of the liquid crystal injection method of the present invention. An array substrate 1 in which pixels are arranged in a matrix so as to have a screen size of 15 inches on a glass substrate, and each pixel has a TFT element, and red, blue corresponding to each pixel, A polyimide coating PSI-2101 (4.0 wt.%, NMP solution) manufactured by Chisso Corporation was applied by spin coating to each of the color filter substrates 2 having green filters, and the curing conditions were 200 ° C. and 1 hour. Cured.

Then, after rubbing so that the twist angle of the liquid crystal molecules becomes 90 degrees, the color filter substrate 2 is
A sealing resin 4 was printed so that two injection ports 3 were formed on each of two opposite sides, and the sealing resin 4 was attached to the array substrate 1 via a 5.0 μm glass fiber to form a liquid crystal cell 5.
This liquid crystal cell was placed horizontally in a vacuum vessel and
Reduce pressure to Pa.

In this state, the liquid crystal 6 defoamed in advance (ZLI-1565 manufactured by Merck & Co., containing the chiral component CB-15)
0.3 ml is dripped from the liquid crystal supply nozzle 6 to each inlet 3. Then, nitrogen gas is gradually introduced into the vacuum container to return it to normal pressure. As a result, the liquid crystal was filled in the liquid crystal cell due to the pressure difference between the inside and outside of the cell, and the injection port 3 was sealed with the ultraviolet curable resin. This was designated as liquid crystal display element A.

As a comparative example, a liquid crystal cell having two injection ports similarly formed on only one side of the panel was injected with the same liquid crystal material under a reduced pressure of 0.133 Pa by a conventional method to obtain a liquid crystal display element. It was set to B.

The time required to fill the liquid crystal at this time, and 6
A comparison of the voltage holding ratios measured at 0 ° C is shown in (Table 1). If the composition of the liquid crystal changes during injection or is contaminated with impurities, the voltage holding ratio decreases.

[0019]

[Table 1]

As is clear from (Table 1), since there are a plurality of injection ports on a plurality of sides, the liquid crystal filling time can be shortened. Furthermore, in order to supply the liquid crystal directly from the nozzle,
It is of great practical value because it can prevent contamination by impurities and compositional change due to reduced pressure, and has a high voltage holding ratio and reliability.

(Embodiment 2) (FIG. 2) is a perspective view of a liquid crystal injection apparatus according to the present invention in a vacuum container. On the two sides facing each other,
A 15-inch size liquid crystal panel 5 having two injection ports 3 each, a total of four injection ports 3, was prepared, and one liquid crystal panel 5 was horizontally installed on each shelf provided in the vacuum container. This shelf can be moved up and down and back and forth. Under reduced pressure, the four liquid crystal supply nozzles 7 that were movable in the left-right direction moved to the upper part of each injection port 3 of the uppermost liquid crystal panel 5, and the liquid crystal 6 was dropped and supplied at the same time.

Next, the liquid crystal supply nozzle was moved to the upper part of each inlet of the second liquid crystal panel to drop the liquid crystal. Repeating this, when liquid crystal is supplied to the inlets of all panels, nitrogen gas is gradually introduced into the vacuum container to return the pressure in the vacuum container to normal pressure, and the pressure difference between the inside and outside of the panel causes Liquid crystal was filled in the panel.

Liquid crystals can be injected into 10 panels by one-time reduced pressure injection operation, and the throughput of each panel itself can be improved, which is of great practical value.

Although the throughput can be improved by increasing the number of panels in the vacuum container, the larger the vacuum container, the longer it takes to increase the degree of vacuum. Therefore, the number of panels installed in the vacuum container is 10 to 10. 20 is suitable.

In this embodiment, the liquid crystal panels are movable only in the vertical and front-back directions, but the number of panels is fixed only in one direction of the liquid crystal supply nozzle, or several panels are fixed, and the liquid crystal panels are rotated or moved in the horizontal direction. You may move.

The movement of the shelf for installing the liquid crystal panel and the liquid crystal supply nozzle depends on the position and the number of the inlets of the panel.
You should take an efficient method.

In this experiment, an active matrix type liquid crystal display element was used as the liquid crystal display element, but it goes without saying that a simple type liquid crystal display element can also be filled with liquid crystal by the same filling device.

[0028]

According to the present invention, it is possible to significantly shorten the time for enclosing the liquid crystal panel as compared with the conventional case, and its practical value is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic view of a liquid crystal injection method of the present invention.

FIG. 2 is a perspective view of the liquid crystal injection device of the present invention in a vacuum container.

FIG. 3 is a perspective view of a conventional liquid crystal injection device in a vacuum container.

[Explanation of symbols]

 1 Array Substrate 2 Color Filter Substrate 3 Pouring Port 4 Seal Resin 5 Liquid Crystal Panel 6 Liquid Crystal 7 Liquid Crystal Supply Nozzle 8 Liquid Crystal Reservoir

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirofumi Minamoto 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A panel not filled with liquid crystal, which has a plurality of injection ports on at least two sides of the panel, is installed horizontally in a vacuum container, and a predetermined amount of liquid crystal is supplied from the liquid crystal supply nozzle to each injection port. Liquid crystal injection method to supply. 2. A liquid crystal injection device having a shelf for horizontally mounting at least one or more panels in a vacuum container and a nozzle for discharging a predetermined amount of liquid crystal from a liquid crystal tank.