JPH06175097A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device having small thermal strains and mechanical strains and high accuracy and the process for production of this display device. CONSTITUTION:This process for production of the liquid crystal display device formed by sealing a liquid crystal between two sheets of substrates with electrodes consists in sticking the substrates 11 to each other after reducing the pressure in a gap 14 between the substrates 11, then injecting the liquid crystal 15 into the gap 14 between the substrates 11. The substrates 11 and sealing material 12 of this liquid crystal display device formed by adhering two sheets of the substrates with electrodes with a sealing material and sealing the liquid crystal into the gap formed between the substrates remain in the adhered state under a reduced pressure so that air does not remain between both.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which liquid crystal is sealed between two substrates with electrodes and a method for manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal display device has a structure in which two substrates with electrodes are adhered to each other with a sealing material so that liquid crystal can be enclosed in a gap formed between the substrates.

Conventionally, a thermosetting type sealing material is generally used as the sealing material. The sealing material is sandwiched between two substrates, and the substrates are heated while being pressed from above and below to cure the sealing material. Usually, the sealing material includes a spacer for ensuring a gap.

[0004]

However, in the above manufacturing method, since the sealing material has to be heated to a high temperature of hundreds of tens of degrees, it is not possible to prevent residual thermal strain caused by cooling after bonding. In addition, when pressing with an elastic body to pressurize, it is difficult to pressurize the substrate uniformly,
Mechanical distortion was unavoidable. Therefore, the thickness accuracy of the liquid crystal display device cannot be sufficiently improved.

Further, conventionally, since the substrate and the sealing material were bonded under atmospheric pressure, it was not possible to completely prevent air from remaining on the joint surface between them. Even a very small amount of residual air may deteriorate the adhesion between the sealing material and the substrate, or may exude into the liquid crystal when the device is used and adversely affect the liquid crystal such as oxidation.

An object of the present invention is to solve the problems of the prior art and to provide a high-precision liquid crystal display device having small thermal strain and mechanical strain and a manufacturing method thereof.

[0007]

According to the present invention, in a method of manufacturing a liquid crystal display device in which a liquid crystal is sealed between two substrates with electrodes, the gap 14 between the substrates 11 is depressurized to bond the substrates 11. There is provided a method for manufacturing a liquid crystal display device, characterized in that the liquid crystal 15 is injected into the gaps 14 between the substrates 11 after the adjustment.

Further, according to the present invention, in the liquid crystal display device in which the two substrates with electrodes are adhered with a sealant and the liquid crystal is sealed in the gap formed between the substrates, the substrate 11
Also provided is a liquid crystal display device characterized in that the seal 12 material is adhered under a reduced pressure and no air remains between the two.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a liquid crystal display device 1 for displaying an image according to the present invention.
It is an assembly drawing which shows 0 typically.

On the substrate surface of the electrode-attached substrate 11, thin film transistor elements serving as image elements for image display and switching elements are appropriately formed by photolithography or the like. Further, a large number of extraction electrodes for scanning image signals and signals are formed around the screen, and an alignment film is applied so as to cover the screen. However, these members are omitted in the drawings for simplification.

On one of the substrates 11, an ultraviolet-curable sealing material (agent) 12 is applied in a pattern. An injection port 13 for injecting liquid crystal is formed in the sealing material 12. The seal material 12 includes a normal spacer (not shown). The spacer has a predetermined size and has a function of adjusting the gap between the substrates 11 to a predetermined width.

Referring to FIG. FIG. 2 is a sectional view conceptually showing the method for manufacturing a liquid crystal display device of the present invention.

The two substrates 11 sandwiching the sealing material 12 are properly positioned and superposed. Two flat glass plates 21 are arranged above and below the substrate 11.
The glass plate 21 is larger than the substrate 11. The elastic body 22 is sandwiched between the two glass plates 21, and the joint surface between the two is airtight. The elastic body 22 is arranged near the periphery of the glass plate 21 so as to surround the substrate 11. An airtight chamber 30 is defined by the two glass plates 21 and the elastic body 22.

One end of a pipe 24 is connected to the chamber 30,
A vacuum pump 23 with a controller is provided at the other end of the tube 24. A pressure gauge 25 is arranged in the middle of the pipe 24.

When the vacuum pump 23 is operated to reduce the pressure in the chamber 30, the glass plate 21 is pushed at atmospheric pressure. As a result, the substrates 11 are evenly pressed, and the gap 14 between the two substrates 11 is adjusted to, for example, 5 μm by the spacer. At this time, the distance between the glass plates 21 is, for example, about 2.2 mm.
It is adjusted to.

In this way, the seal material 12 is irradiated with ultraviolet rays UV while the pressure inside the gap 14 is reduced.
Cure 2 The substrates are bonded together by hardening the sealing material 12.

Next, liquid crystal is injected from the injection port 13 into the gap 14. In this embodiment, a liquid crystal supply source 26 is connected in the middle of the tube 24 via a valve 27. Therefore,
If the valve 27 is opened while maintaining the reduced pressure inside the chamber 30, the liquid crystal is automatically injected into the gap 14. The liquid crystal may be filled by immersing the substrate in the liquid crystal container.

After the filling of the liquid crystal is completed, a UV-curable sealing material is attached to the injection port 13 and ultraviolet rays are radiated to the injection port 13 to close the injection port 13 and seal the liquid crystal. In this way
The liquid crystal display device shown in FIG. 4 is obtained.

In the depressurizing step of this manufacturing method, the inside of the gap 14 is also depressurized like the chamber 30. this is,
This is because the gap 14 between the substrates 11 and the inside of the chamber 30 communicate with each other through the injection port 13 of the sealing material 12. In this way, the substrate 11 and the sealing material 12 are pressed against each other under reduced pressure, and the bonding is performed in a state where there is substantially no air between them, so that no air is completely present between the substrate 11 and the sealing material 12. Good adhesion can be formed without remaining.

Another embodiment of the method of the present invention will be briefly described with reference to FIG. In this embodiment, a glass plate is not used, and only the elastic body 32 is arranged so as to surround the outer periphery of the substrate 12. At this time, it is important that the inner periphery of the elastic body 32 and the outer periphery of the substrate are hermetically engaged. Then, one end of the pipe 24 is arranged near the injection port 13 to reduce the pressure in the gap 14. Since the liquid crystal cell is kept under the atmospheric pressure, it is possible to apply a maximum pressure of about 1 kgf / cm ² to the outer surface of the substrate by reducing the pressure inside the cell.

Also in this embodiment, since the substrate 11 and the sealing material 12 are adhered to each other under reduced pressure, no air remains between the substrate 11 and the sealing material 12, and very good adhesion can be formed. .

The embodiment of FIG. 3 is particularly convenient for manufacturing a large-sized liquid crystal display device. Manufacture large liquid crystal display device in advance,
Finally, the product can be efficiently produced by cutting it into a desired size.

FIG. 4 shows a liquid crystal display device 10 manufactured by the method of FIG. 2 or 3. Reference numeral 15 indicates the liquid crystal injected into the gap. Since the substrate 11 and the sealing material 12 are bonded under reduced pressure, substantially no air remains between the substrate 11 and the sealing material 12.

[0024]

According to the method of manufacturing a liquid crystal display device of the present invention, the gap between the substrates 11 is reduced to perform the bonding, so that air is completely prevented from remaining in the joint portion. It is possible, and very good bonding is possible. Further, since the two substrates 11 are evenly pressed by the atmospheric pressure when the pressure is reduced, the mechanical strain is suppressed to the minimum, and the bonding can be performed accurately. Therefore, according to the method of the present invention, a high quality liquid crystal display device can be manufactured.
Further, the method of the present invention is also suitable for manufacturing a large-sized liquid crystal display device, and can manufacture a large-sized high-quality liquid crystal display device with high yield.

Further, when the ultraviolet curable sealing material 12 is used and the sealing material 12 is cured by being irradiated with ultraviolet rays, the bonding can be performed without thermal strain, so that the accuracy can be further improved. it can.

In the liquid crystal display device of the present invention, since the substrate 11 and the sealing material 12 are adhered under reduced pressure,
There is no air remaining between them, and there is no risk that the adhesion between the substrate and the sealing material will change over time and deteriorate, or that air will seep into the liquid crystal during use. In addition, mechanical strain can be suppressed to a minimum, and the thickness of the gap between the substrates can be adjusted with high accuracy.

The present invention is not limited to the above embodiment. For example, it is possible to simultaneously manufacture a plurality of liquid crystal display devices by arranging a plurality of sets of substrates in series or in parallel between glass plates.

[Brief description of drawings]

FIG. 1 is an assembly view schematically showing an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a sectional view showing an embodiment of a method for manufacturing a liquid crystal display device of the present invention.

FIG. 3 is a sectional view showing another embodiment of the method for manufacturing a liquid crystal display device of the present invention.

FIG. 4 is a sectional view schematically showing an embodiment of the liquid crystal display device of the present invention.

[Explanation of symbols]

 10 Liquid Crystal Display Device 11 Substrate with Electrode 12 Sealing Material 13 Injection Port 14 Gap 15 Liquid Crystal 21 Glass Plates 22, 32 Elastic Body 23 Vacuum Device 24 Tube 25 Pressure Gauge 26 Liquid Crystal Supply Source 27 Valve ◆

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[Procedure amendment]

[Submission date] December 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

On one of the substrates 11, an ultraviolet-curable sealing material (agent) 12 is applied in a pattern. An injection port 13 for injecting liquid crystal is formed in the sealing material 12. A normal spacer 16 is included between the substrates 11 and in the sealing material 12. The spacer 16 has a predetermined size and has a function of adjusting the gap between the substrates 11 to a predetermined width.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (3)

[Claims] 1. A method for manufacturing a liquid crystal display device comprising a liquid crystal sealed between two substrates with electrodes, wherein the gap (14) between the substrates (11) is depressurized to bond the substrates (11) together. After that, a liquid crystal (15) is injected into the gap (14) between the substrates (11), which is a method for manufacturing a liquid crystal display device. 2. A method of manufacturing a liquid crystal display device comprising a liquid crystal sealed between two electrode-attached substrates, wherein one of the substrates (11) contains an ultraviolet curable sealant (1).
2) coating step, superimposing the two substrates (11), and exhausting the atmosphere from the gap between the substrates (11) in a state where the two substrates (11) are superposed to reduce the pressure. And a step of curing the sealing material (12) by irradiating ultraviolet rays, and the substrate (1
1. A method for manufacturing a liquid crystal display device, which comprises the step of injecting a liquid crystal (15) in a state where 1) is overlaid. 3. A liquid crystal display device in which two electrodes-attached substrates are bonded with a sealing material, and liquid crystal is sealed in a gap formed between the substrates, the substrate (11) and the sealing material (1
2. A liquid crystal display device characterized in that 2) is adhered under reduced pressure and no air remains between the two.