JPH05165039A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent occurrence of such a phenomenon that the gas attached to the surface of a spacer material forming a cell gap or surface unevenness in a liquid crystal display cell or remains in a liquid crystal layer in the form of bubbles near the seal on the side opposite the liquid crystal injection port and that these bubbles emerge at the display picture element part with elapse of the time to bring about failure, which is more likely when liquid crystal display device is going to be equipped with a greater screen to result in a greater size of the construction. CONSTITUTION:The liquid crystal injecting form is given a certain trend according to the shape of a liquid crystal injection port 10 and its location so that the liquid crystal injection ending part is specified, and a bubble sump 7 is provided in this specified position. The bubble sump 7 is formed by providing a dimple in either or both of the two mating electrode base boards so that the liquid crystal layer has a greater thickness (gap of liquid crystal display cell) than the display picture element part. A light shield film is provided on either or both of the electrode base boards in the place where dimple is provided as bubble sump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a liquid crystal display device using a method of injecting liquid crystal into a liquid crystal layer sandwiched between two electrode substrates facing each other by a vacuum injection method.

[0002]

2. Description of the Related Art Recent liquid crystal display devices are used as display devices for notebook personal computers, workstations for personal computers, and the like, and their screens are becoming larger.

A vacuum injection method is generally used as a method for injecting a liquid crystal between two electrode substrates facing each other to form a liquid crystal layer.

This is because a liquid crystal display cell and liquid crystal are prepared in a vacuum container and the inside of the vacuum container is set to 1 × 10 ^-3 by a vacuum pump.
To 1 × 10 ⁻⁵ torr and then the liquid crystal display cell is immersed in the liquid crystal. Next, when the vacuum container in the vacuum state is leaked and returned to the atmospheric pressure, the liquid crystal is discharged to the liquid crystal display cell due to the pressure difference between the atmospheric pressure and the atmospheric pressure in the liquid crystal display cell and the action of the capillary phenomenon of the liquid crystal. It is a method of forming a liquid crystal layer by injection.

[0005]

However, in this manufacturing method, as the screen size of the liquid crystal display device increases and the size of the liquid crystal display device increases, the gas adhering to the surface of the spacer material forming the irregularities and the cell gaps in the liquid crystal display cell becomes liquid crystal. Bubbles remain in the liquid crystal layer near the seal on the opposite side of the inlet. Then, as time passes, the bubbles appear in the display pixel portion and become defective.

Regarding the bubbles remaining in the liquid crystal layer, attempts have been made to eliminate the bubbles by increasing the capacity of the vacuum pump, but there are problems in equipment cost and productivity.

On the other hand, the following measures have been proposed or implemented on the assumption that air bubbles will be generated. The contents and challenges will be explained.

[0008] First of all, Japanese Patent Laid-Open Publication No. Showa 63-
The liquid crystal injection method disclosed in Japanese Patent No. 223619 will be described with reference to FIG.

Elution into the liquid crystal at the time of liquid crystal injection so that the liquid crystal layer is divided on the opposite side of the liquid crystal injection port 10 provided on one side of the sealing material 3 surrounding the liquid crystal layer sandwiched between the upper substrate 1 and the lower substrate 2 facing each other. The impurity reservoir 5 is provided, the impurity reservoir 5 is cleaved at the end of the liquid crystal injection, and the liquid crystal passage 4 is then sealed to complete the liquid crystal injection step.

This prior art is characterized in that impurities eluted at the time of injecting liquid crystal are collected in an impurity reservoir and then removed. Although no mention is made of bubbles generated by residual gas, structurally, as a countermeasure against bubbles, You can expect an effect.

However, this conventional technique has the following problems. The process of complicating the part where impurities are accumulated and sealing the cleaved part becomes complicated, which causes an increase in cost and a decrease in yield.

In the TFT driving liquid crystal panel, electrode terminals for giving a driving signal are arranged around the liquid crystal display device. Even if the method of cleaving and removing the impurity reservoir as in this reference is effective as a bubble reservoir, it is not practical for a liquid crystal display device in which at least electrode terminals are arranged on the opposite side of the liquid crystal inlet.

Next, Japanese Patent Laid-Open Publication No. Showa 63-2895.
Regarding the manufacturing method of the liquid crystal display device described in Japanese Patent No. 25,
This will be described with reference to FIGS. 6 and 7.

At least one liquid crystal injection port 10 is provided on one side of the sealing material 3 so as to surround the liquid crystal layer sandwiched between the upper substrate 1 and the lower substrate 2 which are opposed to each other. The liquid crystal is injected by forming the bubble reservoir inlet 6 on a diagonal line with the liquid crystal injection port 10 while forming the liquid crystal injection port 10 in a biased position. Then, after the bubble reservoir 7 is cut, the bubble reservoir inlet 6 at the cut portion is sealed with a sealant 8'as shown in FIG. 6 to prevent bubbles generated in the liquid crystal layer.

From the contents described in Japanese Patent Laid-Open No. 63-289525, the liquid crystal injection port 10 is formed at a position deviated to the left or right with respect to the center line 9 of the liquid crystal display device.
The effect of collecting bubbles in the bubble reservoir 7 can be expected by using the method of injecting liquid crystal by forming the bubble reservoir inlet 6 on a diagonal line with the liquid crystal inlet 10.

However, as pointed out in the description of the former prior art, the step of complicating the portion where impurities are accumulated and sealing the cleaved portion becomes complicated, resulting in an increase in cost and a reduction in yield. Furthermore, in the latter prior art, as shown in FIG.
In consideration of the electrode terminal 11, the terminal portion is devised so as to remain after the bubble reservoir is cut, but the method of cutting the seal adhesive portion where the bubble reservoir inlet 6 is formed is not described in this reference.

On the other hand, according to the result of our experiment, the bubble reservoir inlet 6 is reliably and stably left without any influence on the electrode terminal 11.
Is difficult to cut.

According to the present invention, as the screen size of the liquid crystal display device becomes larger and larger, the gas adhering to the surface of the spacer material forming the irregularities and cell gaps in the liquid crystal display cell is near the seal on the opposite side of the liquid crystal injection port. Bubbles in the liquid crystal layer.
Then, it provides a countermeasure against the problem that the bubbles appear in the display pixel portion and become defective with the passage of time.

[0019]

In order to solve the above problems, according to the present invention, a side opposite to a liquid crystal injection port provided on one side of a sealing material surrounding a liquid crystal layer sandwiched between two electrode substrates facing each other. Install a bubble trap near the seal. In order to give a certain tendency to the liquid crystal injection form into the liquid crystal layer and to identify the liquid crystal injection end portion, the shape is the same on one side of the sealing material that surrounds the liquid crystal layer sandwiched between two electrode substrates facing each other. The liquid crystal injection port is provided at each of asymmetrical positions with respect to a center line passing through the side where the liquid crystal layer and the liquid crystal injection port are provided.

Alternatively, a method is used in which liquid crystal injection ports having different shapes are provided at positions on the left and right with respect to the center line passing through the side where the liquid crystal layer and the liquid crystal injection port are provided. The shape of the bubble reservoir at this time is a key shape so that the bubbles can be more reliably collected and trapped.

For the bubble reservoir, a method is used in which either or both of the two opposing electrode substrates are provided with a depression so that the thickness of the liquid crystal layer (gap of the liquid crystal display cell) is larger than that of the display pixel portion. Then, a method is used in which a light-shielding film is provided on either or both of the two electrode substrates facing the location where the recess is formed and the bubble is trapped.

[0022]

By using the above method, the gas adhering to the surface of the spacer material forming the irregularities and cell gaps in the liquid crystal display cell can be changed by changing the shape or position of the liquid crystal injection port. That is, the liquid crystal injection speed can be made to have a certain form, and the liquid crystal injection end portion can be specified. By providing a bubble reservoir at that position (the liquid crystal injection end portion), the bubbles can be reliably collected and trapped in the bubble reservoir. Further, by providing a light-shielding film on either or both of the two electrode substrates facing the place where the bubble is stored, it is possible to prevent the transmitted light from the bubble portion.

[0023]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a liquid crystal display cell 12 in which an upper substrate and a lower substrate are opposed to each other and formed by a sealing material 3. The center line 9 of the liquid crystal display cell 12 is provided on one side of the sealing material 3.
Liquid crystal inlets 10 and 10 'are provided on the left and right sides of the cell, and a bubble reservoir 7 is provided near the seal on the opposite side.

Reference numeral 1 in FIG. 2 is an upper substrate, which is a lower substrate 2 and a sealing material 3.
Pasted together. The thickness of the liquid crystal layer of the bubble reservoir 7 (gap of the liquid crystal display cell) is made larger than that of the display pixel portion 13. In addition, in order to prevent light from passing through the air bubbles, light shielding films 14 and 14 'that prevent light from passing are provided on both the upper substrate 1 and the lower substrate 2. Although the light shielding films are provided on both sides in this embodiment, the same effect can be expected with either one.

Using this embodiment shown in FIG. 1 and FIG. 2, it is as follows. The liquid crystal display cell and the liquid crystal of this embodiment shown in FIGS. 1 and 2 are prepared in a vacuum container, and the inside of the vacuum container is evacuated to a vacuum state of about 1 × 10 ⁻³ to 1 × 10 ⁻⁵ torr by a vacuum pump. After that, the liquid crystal display cell is immersed in the liquid crystal.

Next, when the vacuum container in the vacuum state is leaked and returned to the atmospheric pressure, the pressure difference between the atmospheric pressure and the atmospheric pressure in the liquid crystal display cell and the action of the capillary action of the liquid crystal cause the liquid crystal display cell. The liquid crystal is injected from the two liquid crystal injection ports 10 and 10 ′, and the injection is gradually progressed from the liquid crystal injection port side to the opposite side to complete the injection (in the present embodiment, the vacuum arrival time in the liquid crystal display cell and the liquid crystal display cell). Two liquid crystal injection ports are provided for the purpose of shortening the injection time.)

Then, the bubble reservoir is provided on the opposite side of the injection port where the injection is completed, and the bubbles pushed together with the injection of the liquid crystal are collected in the bubble reservoir. Then, the bubbles once collected in the thick bubble reservoir of the liquid crystal layer are trapped in the bubble reservoir without moving to the display pixel portion where the liquid crystal layer is thin.

A second embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a liquid crystal display cell in which an upper substrate and a lower substrate are opposed to each other and formed by a sealing material 3. Liquid crystal inlets 10 and 10 'of the same shape are provided on one side of the sealing material 3 on the left and right sides of the center line 9 of the liquid crystal layer 15 at positions A and B from the center line.

Since the distance A from the center line is made larger than B, the liquid crystal injection port as a whole is located at a position deviated to the distance A side with respect to the liquid crystal layer. There is a hook-shaped bubble reservoir 7 near the seal on the diagonal side at a position biased to the distance A side. The bubble reservoir has the same structure as that described in FIG.

Using the present embodiment shown in FIG. 3, it is as follows. After preparing the liquid crystal display cell and the liquid crystal of this embodiment shown in FIG. 3 in a vacuum container and making the inside of the vacuum container a vacuum state of about 1 × 10 ⁻³ to 1 × 10 ⁻⁵ torr by a vacuum pump. The liquid crystal display cell is immersed in the liquid crystal. Next, when the vacuum container in the vacuum state is leaked to the atmospheric pressure and returned to the atmospheric pressure, the two liquid crystal display cells are operated due to the pressure difference between the atmospheric pressure and the atmospheric pressure in the liquid crystal display cell and the action of the liquid crystal capillary phenomenon. The liquid crystal is injected from the liquid crystal injection ports 10 and 10 ', and the injection is gradually progressed from the liquid crystal injection port side to the opposite side, and the injection is finished. At this time, since the liquid crystal injection port is biased toward the distance A side, the liquid crystal injection proceeds from the distance A side.

As a result, the position of the bubble reservoir provided in the diagonal direction on the side of the biased distance A becomes the liquid crystal injection termination site. This means that the bubbles that have been pushed together with the liquid crystal injection are collected in the bubble reservoir. Then, the bubbles once collected in the thick bubble reservoir of the liquid crystal layer are trapped in the bubble reservoir without moving to the display pixel portion where the liquid crystal layer is thin.

A third embodiment of the present invention will be described with reference to the drawings. FIG. 4 shows a liquid crystal display cell in which an upper substrate and a lower substrate are opposed to each other and are formed by a sealing material 3. Liquid crystal inlets 10 and 10 ′ having different shapes (different cross-sectional areas of the liquid crystal inlets) are provided on one side of the sealing material 3 on the left and right sides of the center line 9 of the liquid crystal layer 15 such that the width of the liquid crystal inlets is E> F. Provided. Then, there is a key-shaped bubble reservoir 7 near the diagonal seal on the liquid crystal injection port 10 side (E side where the width of the injection port is large). The bubble reservoir has the same structure as that described in FIG.

Using the present embodiment shown in FIG. 4, it is as follows. After preparing the liquid crystal display cell and the liquid crystal of this embodiment shown in FIG. 4 in a vacuum container and making the inside of the vacuum container a vacuum state of about 1 × 10 ⁻³ to 1 × 10 ⁻⁵ torr by a vacuum pump, The liquid crystal display cell is immersed in the liquid crystal. Next, when the vacuum container in the vacuum state is leaked to the atmospheric pressure and returned to the atmospheric pressure, the two liquid crystal display cells are operated due to the pressure difference between the atmospheric pressure and the atmospheric pressure in the liquid crystal display cell and the action of the liquid crystal capillary phenomenon. The liquid crystal is injected from the liquid crystal injection ports 10 and 10 ', and the injection is gradually progressed from the liquid crystal injection port side to the opposite side, and the injection is finished. At this time, the width of the liquid crystal injection port is larger on the liquid crystal injection port 10 side, so that liquid crystal injection proceeds from the liquid crystal injection port 10 side.

As a result, the position of the bubble reservoir provided in the diagonal direction on the liquid crystal injection port 10 side becomes the liquid crystal injection end site.
This means that the bubbles that have been pushed together with the liquid crystal injection are collected in the bubble reservoir. Then, the bubbles once collected in the thick bubble reservoir of the liquid crystal layer are trapped in the bubble reservoir without moving to the display pixel portion where the liquid crystal layer is thin.

[0036]

As described above, according to the present invention, the liquid crystal injection form is made to have a certain tendency depending on the shape and position of the liquid crystal injection port, the liquid crystal injection end portion is specified, and the bubble reservoir is provided at the specified position. Thus, it is possible to prevent bubbles from being generated in a place other than the bubble reservoir, and to prevent bubbles from appearing in the display pixel portion thereafter by surely collecting and trapping the bubbles in the bubble reservoir.

[Brief description of drawings]

FIG. 1 is a plan view showing a basic configuration of a liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view showing the structure of a liquid crystal reservoir in one embodiment of the present invention.

FIG. 3 is a front view showing a position of a liquid crystal inlet and a liquid crystal reservoir in one embodiment of the present invention.

FIG. 4 is a front view showing the shape of a liquid crystal inlet and a liquid crystal reservoir in one embodiment of the present invention.

FIG. 5 is a plan view of a conventional liquid crystal cell.

FIG. 6 is a plan view of a conventional liquid crystal cell.

FIG. 7 is a plan view of a conventional liquid crystal cell.

[Explanation of symbols]

 1 Upper Substrate 2 Lower Substrate 3 Sealing Material 4 Liquid Crystal Passing Section 5 Impurity Reservoir 6 Bubble Reservoir Inlet 7 Bubble Reservoir 8 and 8'Sealant 9 Center Line 10 and 10 'Liquid Crystal Inlet 11 Electrode Terminal 12 Liquid Crystal Display Cell 13 Display Pixel Part 14, 14 'Light-shielding film 15 Liquid crystal layer

Claims (6)

[Claims] 1. A liquid crystal display device characterized in that a bubble reservoir is provided in the vicinity of a seal opposite to a liquid crystal injection port provided on one side of a sealing material surrounding a liquid crystal layer sandwiched between two electrode substrates facing each other. .. 2. A liquid crystal injection port having the same shape on one side of a sealing material that surrounds a liquid crystal layer sandwiched between two electrode substrates facing each other, with a center line passing through the side where the liquid crystal layer and the liquid crystal injection port are provided. On the other hand, by installing them in asymmetrical positions,
A liquid crystal display device characterized in that a liquid crystal injection form into the liquid crystal layer has a certain tendency to specify a liquid crystal injection end portion and a bubble reservoir is provided at the liquid crystal injection end portion. 3. A liquid crystal injection port having a different shape is formed on one side of a sealing material that surrounds a liquid crystal layer sandwiched between two electrode substrates facing each other, and the liquid crystal layer and the liquid crystal injection port are provided on the left and right with respect to a center line passing through the side where the liquid crystal injection port is provided. The liquid crystal display device is characterized in that the liquid crystal injecting form into the liquid crystal layer has a certain tendency by specifying the liquid crystal injecting end part and the liquid crystal injecting end part is provided with a bubble reservoir. .. 4. A bubble reservoir is provided by forming a recess in one or both of the two opposing electrode substrates so that the thickness of the liquid crystal layer (gap of the liquid crystal display cell) is larger than that of the display pixel portion. Liquid crystal display device. 5. A liquid crystal display device, characterized in that a light-shielding film is provided on either or both of two electrode substrates facing a place where a recess is provided to form a bubble reservoir. 6. The liquid crystal display device according to claim 2, wherein the bubble reservoir has a key shape.