JPH0688951A - Method for injecting liquid crystal - Google Patents

Abstract

PURPOSE:To make the injection of a liquid crystal into a liquid crystal cell possible without changing a cell gap by pressurizing liquid crystal cells from both surface sides and injecting liquid crystals therein while maintaining the pressurizing state. CONSTITUTION:The liquid crystal cells 1 are laminated with spacer sheets 21 held therebetween and the laminate of the cells formed in such a manner is held by a pair of pressurizing plates 20. Cell gap materials are dispersed in the liquid crystal cells 1, and therefore the cell gaps do not change. The laminate of the cells in the pressurizing state is then carried into an injection device and after a vacuum state is maintained in the injection device, the laminate of the cells is lowered to immerse the liquid crystal injection ports 5 of the respective liquid crystal cells 1 into a liquid crystal bath 11 of a liquid crystal tray 10. The liquid crystals are then injected into the liquid crystal cells 1 by restoring the atm. pressure in the device. Namely, the liquid crystals are injected by the pressure difference between the pressure in the liquid crystal cells 1 in the vacuum state and the pressure of the bath surface of the liquid crystal bath 11. Then, the change of the cell gaps does not arise when the liquid crystals are injected therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for injecting liquid crystal into a liquid crystal cell.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device is constructed by assembling a liquid crystal cell by bonding a pair of transparent substrates through a frame-shaped sealing material surrounding a liquid crystal enclosing region, and then injecting a liquid crystal into the liquid crystal cell by a vacuum injection method. Is injected, and then the liquid crystal injection port is sealed. FIG. 2 shows a conventional liquid crystal injection method by a vacuum injection method.

First, the liquid crystal cell 1 will be described. In the liquid crystal cell 1, a transparent electrode for display and an alignment film (not shown) for aligning liquid crystal molecules are provided on a transparent plate made of glass or the like. The pair of transparent substrates 2 and 3 thus formed are joined and assembled via a frame-shaped sealing material 4 surrounding a liquid crystal enclosing region. One end surface of the liquid crystal cell 1 is provided with a part of the sealing material 4. A liquid crystal injection port 5 formed by being omitted is provided.

Although not shown, a transparent gap material composed of short cut glass fibers, spherical resin particles or the like is disposed in a dispersed state in the liquid crystal enclosing area in the liquid crystal cell 1, and both substrates 2 , The gap between the two, ie, the cell gap, is regulated by the gap material. Liquid crystal cell 1
The liquid crystal is injected into the chamber by a vacuum injection method using an injection device (not shown) including a pressure container as follows.

First, the liquid crystal cell 1 is carried into the injection device, and the liquid crystal cell 1 is supported by an elevating mechanism (not shown) inside the device with the liquid crystal injection port 5 facing downward. The inside of the equipment is evacuated. Next, the liquid crystal cell 1 is lowered by the elevating mechanism, and the liquid crystal dish 1 arranged in the apparatus is moved.
The liquid crystal injection port 5 of the liquid crystal cell 1 is dipped in the liquid crystal bath 11 in 0, and in this state, the inside of the device is returned to atmospheric pressure or pressurized to a pressure slightly higher than atmospheric pressure, so that the liquid crystal cell 1 in vacuum state Then, the liquid crystal is injected by the pressure difference from the pressure applied to the bath surface of the liquid crystal bath 11. The liquid crystal cell 1 into which the liquid crystal has been injected is taken out from the injection device, and then the liquid crystal injection port 5 is sealed with a sealing resin.

[0006]

The display quality of a liquid crystal display device depends on the thickness of the liquid crystal layer, that is, the liquid crystal cell 1.
Therefore, in order to obtain a liquid crystal display device having good display quality, it is necessary to set the cell gap of the liquid crystal cell 1 to a predetermined value.

However, the above-described conventional liquid crystal injection method has a problem that when the liquid crystal is injected into the liquid crystal cell 1, the liquid crystal cell 1 is deformed into a bulge and the cell gap is changed.

This is because the pressure of the liquid crystal injected into the liquid crystal cell 1 causes the substrates 2 and 3 of the liquid crystal cell 1 to warp in a state where the central portion swells to the outer surface side as shown by the chain line in FIG. This is because the liquid crystal having a volume larger than that volume will enter the cell 1.
Since the liquid crystal excessively injected into the liquid crystal cell 1 cannot be removed by the restoring force of the substrates 2 and 3, the substrates 2 and 3 remain bulged to the outer surface side, and the cell gap of the liquid crystal cell 1 is large. turn into.

Therefore, conventionally, after the liquid crystal is injected into the liquid crystal cell 1, a pair of pressure plates 12 are provided as shown in FIG.
By pressing the liquid crystal cell 1 from both sides thereof, the excessively injected liquid crystal is pushed out of the cell through the liquid crystal injection port 5 to correct the cell gap, and then the liquid crystal injection port 5 is sealed.

Reference numeral 13 in FIG. 3 is a spacer sheet made of a rubber plate or the like interposed between the pressure plate 12 and the liquid crystal cell 1, and the liquid crystal cell 1 is pressed through the spacer sheet 13. ing.

However, as described above, the liquid crystal cell 1
After the liquid crystal is injected into the inside, if the liquid crystal cell 1 is pressurized to correct the cell gap and then the liquid crystal injection port 5 is sealed, the work from the liquid crystal injection to the injection port sealing is troublesome. Further, since the liquid crystal inlet 5 is in contact with air for a long time even after the liquid crystal is injected, the liquid crystal is deteriorated, and dust in the air enters from the liquid crystal inlet 5 and mixes with the liquid crystal in the liquid crystal cell 1 to manufacture. The electro-optical characteristics of the produced liquid crystal display element may be adversely affected.

Moreover, conventionally, the substrates 2 and 3 of the liquid crystal cell 1 are used.
However, when the liquid crystal is injected, the liquid crystal swells and deforms to the outer surface side due to the pressure of the injected liquid crystal, and when the cell gap is corrected, the swelling deformation is corrected by being pressed from the outer surface side. The gap becomes non-uniform, and as a result, display unevenness may occur in the manufactured liquid crystal display element.

An object of the present invention is to inject liquid crystal into a liquid crystal cell by a vacuum injection method, but to inject the liquid crystal into the liquid crystal cell without changing the cell gap,
It is an object of the present invention to provide a liquid crystal injection method that can eliminate the need to correct the cell gap after liquid crystal injection.

[0014]

According to the present invention, there is provided a method of injecting a liquid crystal by a vacuum injection method into a liquid crystal cell in which a pair of transparent substrates are bonded together through a frame-shaped sealing material surrounding a liquid crystal enclosing region. It is characterized in that the cell is pressurized from both sides thereof, and liquid crystal is injected into the liquid crystal cell while maintaining the pressurized state.

[0015]

In this way, when the liquid crystal cell is pressurized from both sides thereof and the liquid crystal is injected into the liquid crystal cell, the substrate of the liquid crystal cell does not bulge and deform outward due to the pressure of the injected liquid crystal. The liquid crystal does not exceed the volume of the liquid crystal cell, and therefore the cell gap of the liquid crystal cell does not change.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. In the figure, the liquid crystal cell 1 has the sectional structure shown in FIG.

In this embodiment, liquid crystals are simultaneously injected into a plurality of liquid crystal cells 1 by a vacuum injection method. Liquid crystals are injected into the liquid crystal cells 1 by an injection device (not shown) consisting of a pressure resistant container as follows. Do it.

First, a plurality of liquid crystal cells 1 are laminated with a spacer sheet 21 made of a rubber plate or the like sandwiched between the cells with the liquid crystal injection ports facing in the same direction, and the outermost two liquid crystal cells. The spacer sheet 2 is also provided on the outer surface of 1.
1 is piled up, and this cell stack is held between a pair of pressure plates 20.

Next, the pair of pressure plates 20 press each liquid crystal cell 1 at a pressure slightly higher than the pressure of the injected liquid crystal when the liquid crystal is injected into the liquid crystal cell 1 from both sides thereof. In this case, even if the liquid crystal cell 1 is pressed from both sides thereof, the gap material for regulating the cell gap (gap between the two substrates 2 and 3) is arranged in the liquid crystal cell 1 in a dispersed state. , 3 does not flex and deform inward of the cell, and therefore the cell gap of the liquid crystal cell 1 does not change.

The liquid crystal cell 1 is pressurized by, for example, pressing a pair of pressure plates 20 by a pressure mechanism using a hydraulic cylinder or the like, and thereafter, the both pressure plates are fixed by a fixing means such as a bolt. 20 are fixed to each other to maintain the pressurized state.

Next, the cell stack together with the pressure plate 20 is carried into the injecting device while the above-mentioned pressurizing state is maintained, and the cell stack is directed to the liquid crystal injection port 5 of each liquid crystal cell 1 downward. It is supported by an elevating mechanism (not shown) in the apparatus in the closed state.

After this, as in the ordinary vacuum injection method, the inside of the injection device is evacuated, and then the cell stack is lowered by the elevating mechanism to set the liquid crystal injection port 5 of each liquid crystal cell 1.
The liquid crystal is injected into the liquid crystal cell 1 by immersing it in a liquid crystal bath 11 in a liquid crystal dish 10 arranged in the device and returning the device to atmospheric pressure or pressurizing it to a pressure slightly higher than atmospheric pressure in this state. To do.

In this case, the liquid crystal is injected into the liquid crystal cell 1 by the pressure difference between the liquid crystal cell 1 in the vacuum state and the pressure applied to the bath surface of the liquid crystal bath 11. Each liquid crystal cell 1 has its both surfaces. Since the pressure is applied from the side at a pressure slightly higher than the pressure of the injected liquid crystal, the cell gap of the liquid crystal cell 1 does not change when the liquid crystal is injected.

After injecting the liquid crystal into the liquid crystal cell 1, the cell stack is pulled up from the liquid crystal bath 11 and taken out from the injecting device, and the pressure plate 20 is removed to separate the individual liquid crystal cells 1. The liquid crystal injection port 5 of each liquid crystal cell 1 is sealed with a sealing resin.

That is, in the above liquid crystal injection method, the liquid crystal cell 1 is pressed from both sides, and the liquid crystal is injected into the liquid crystal cell 1 while maintaining the pressed state. If the liquid crystal is injected by applying pressure to both sides of the liquid crystal cell 1, the substrates 2 and 3 of the liquid crystal cell 1 will not bulge and deform toward the outer surface side due to the pressure of the injected liquid crystal. Since the liquid crystal does not enter, it is possible to inject an appropriate amount of liquid crystal into the liquid crystal cell 1 and maintain the cell gap at a regular value regulated by the gap material.

Therefore, according to the above liquid crystal injection method, it is not necessary to pressurize the liquid crystal cell after the liquid crystal injection to correct the cell gap as in the case of injecting the liquid crystal into the liquid crystal cell by the conventional injection method. Since the liquid crystal injection port 5 can be immediately sealed after taking out the liquid crystal cell 1 into which the liquid crystal is injected from the injection device, the work from the liquid crystal injection to the injection port sealing can be performed efficiently, and the liquid crystal Since the time during which the liquid crystal injection port is in contact with air after the injection is shortened, the liquid crystal is not deteriorated, and dust in the air is mixed with the liquid crystal in the liquid crystal cell 1 to produce an electric liquid crystal display element. There is almost no adverse effect on the optical characteristics.

Moreover, according to the above liquid crystal injection method, the liquid crystal can be injected into the liquid crystal cell 1 without deforming the substrates 2 and 3 of the liquid crystal cell 1, and the liquid crystal cell is pressed to inject the liquid crystal cell. Since there is no need to correct the gap, the substrates 2 and 3 of the liquid crystal cell 1 are not distorted due to the deformation, and therefore the cell gap of the liquid crystal cell 1 can be kept uniform, so that the manufactured liquid crystal display device has display unevenness. It does not cause

In the above embodiment, a plurality of liquid crystal cells 1 are used.
This is an example of injecting liquid crystal simultaneously into the
The present invention can also be applied to the case of injecting liquid crystal individually into one liquid crystal cell 1, and the pressurizing means and the pressurizing state holding means of the liquid crystal cell 1 are not limited to the above-mentioned means.

[0029]

According to the liquid crystal injection method of the present invention, the liquid crystal cell is pressurized from both sides thereof, and the liquid crystal is injected into the liquid crystal cell while maintaining this pressure state. Although the liquid crystal is injected into the cell, it is possible to inject the liquid crystal into the liquid crystal cell without changing the cell gap, and it is not necessary to correct the cell gap after the liquid crystal is injected.

[Brief description of drawings]

FIG. 1 is a diagram showing a liquid crystal injection method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional liquid crystal injection method.

FIG. 3 is a diagram showing a method of correcting a cell gap of a liquid crystal cell in which liquid crystal is injected by a conventional liquid crystal injection method.

[Explanation of symbols]

 1 ... Liquid crystal cell 10 ... Liquid crystal dish 11 ... Liquid crystal bath 20 ... Pressurization plate 21 ... Spacer sheet

Claims (1)

[Claims] 1. A method of injecting liquid crystal into a liquid crystal cell in which a pair of transparent substrates are bonded together through a frame-shaped sealing material surrounding a liquid crystal enclosing region by a vacuum injection method, wherein the liquid crystal cell is pressed from both sides thereof. A method for manufacturing a liquid crystal element, characterized in that liquid crystal is injected into the liquid crystal cell while maintaining the pressurized state.