JPH05203973A - Manufacture of liquid crystal display element - Google Patents

Abstract

PURPOSE: To improve the utilization efficiency of glass substrates and to decrease cell gap defects at the time of bonding the glass substrates. CONSTITUTION: This process consists of a stage for bonding the upper and lower glass substrates 11, 12 having plural liquid crystal cells, a stage for putting a photosetting resin into the gap delineated between the bonded glass substrates and a stage for curing the photosetting resin by irradiating the resin with UV rays. Resin sealing dams 3b, 3b', 3c, 3c' are so disposed as to limit the photosetting resin to flow into the preset range of the bonded glass substrates 11, 12. These resin sealing dams 3b, 3b', 3c, 3c' are formed in a pair in respective both side marginal parts of the glass substrates 11, 12 so as to close the parts exclusive of the parts in both side marginal parts of the glass substrates 11, 12 where the photosetting resin flows into.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device by forming a plurality of liquid crystal cells on a pair of large glass substrates facing each other and separating the liquid crystal cells from each other by a cutting method. Relates to a method for bonding glass substrates having a plurality of liquid crystal cells, which can increase the effective area of the glass substrates.

[0002]

2. Description of the Related Art One method of manufacturing a general liquid crystal display device is
Forming a pattern on a pair of large glass substrates so that a plurality of liquid crystal cells are arranged in a matrix form, arranging and bonding the glass substrates so as to face each other, and cutting the combined glass substrates. And separating the liquid crystal cells from each other, injecting liquid crystal into each liquid crystal cell through an injection port provided therein, cleaning the liquid crystal cell by closing the injection port, and upper and lower glass substrates of each liquid crystal cell. The process consists of attaching a polarizing plate to each part.

FIG. 1 illustrates a bonded upper and lower glass substrate comprising a plurality of liquid crystal cells, prior to cutting, according to the conventional method described above. FIG. 2 illustrates the effective areas of glass substrates bonded together according to the conventional method illustrated in FIG. On the other hand, FIG. 3 is a sectional view of a general liquid crystal display element.

Referring to FIG. 3, the liquid crystal display element is composed of upper and lower glass substrates 11 and 12 having transparent electrodes 10 and 10a respectively on the inner surfaces facing each other. Glass substrate 1
Alignment films 9 and 9a for aligning liquid crystal in a desired direction are coated on the transparent electrodes 10 and 10a of 1 and 12, respectively. Glass substrates 11 and 12 are spacers 7, 7a, 7b
And 7c are spaced to keep the gap uniform. The peripheral edges of the glass substrates 11 and 12 are closed by an epoxy resin sealing material to define a sealed inner space between the glass substrates. Liquid crystal is housed in the inner space so as to be hermetically sealed. Polarizing plates 6 and 6a
Are provided outside the glass substrates 11 and 12, respectively.

Now, a method of manufacturing the liquid crystal display device having the above structure will be described with reference to FIGS.

First, an ITO (indium oxide / tin oxide) film which is a transparent electrode is vapor-deposited on the opposing glass substrates 11 and 12. A photosensitive resin film is applied on the ITO film and cured. After that, the glass substrates 11 and 1 are formed using an exposure apparatus to form a desired electrode pattern.
2 expose the top. Then, the glass substrates 11 and 12 are etched, washed, and dried to obtain the glass substrates 11 and 12.
The transparent electrodes 10 and 10a are respectively formed on the top. Alignment films 9 and 9a are coated on glass substrates 11 and 12 having transparent electrodes 10 and 10a, and the alignment films are cured, and the surfaces of the alignment films 9 and 9a are soft and velvety. It is rubbed with a cloth. Alignment film 9, 9
The rubbing a is performed so as to have a rubbing twist angle of 90 ° in the case of the TN type liquid crystal and 200 ° to 250 ° in the case of the STN type liquid crystal.

After rubbing the alignment films 9 and 9a, the spacers 7, 7a, 7b and 7c are placed on one of the glass substrates 11 and 12. Then, for sealing, a sealing material 4a made of epoxy resin is applied to desired portions of the glass substrates 11 and 12 by silk screen printing and precured. After the pre-curing of the sealing material 4a of the epoxy resin and before the pressure-curing process in the main curing furnace, the glass substrates 11, 12 are made of a photo-curing resin to prevent the glass substrates 11, 12 from moving. Join processing.

In the conventional method shown in FIG. 1, the bonding process is carried out by dropping a photocurable resin on both side edge portions of the lower glass substrate 12 which are set in advance, that is, the portions 3 and 3a where the cells are not arranged. The glass substrate 12 on the side and the glass substrate 11 on the upper side are combined, the photocurable resin is pre-cured by using ultraviolet rays, and the epoxy resin sealing material 4a precured in the main curing furnace is pressure-cured. And then the glass substrate 11,
This is achieved by sealing 12.

After that, the glass substrates 11 and 12 are cut so as to form individual liquid crystal cells into which liquid crystal is injected through the injection port in the next step. After sealing the inlet, the liquid crystal cell is washed. Polarizing plates 6 and 6a are attached to the outer surfaces of the glass substrates 11 and 12 of each liquid crystal cell. Thus, the liquid crystal display device is manufactured.

[0010]

However, in order to prevent the upper and lower glass substrates from moving after the epoxy resin sealing material 4a is printed and pre-cured and before being pressure-cured in the main curing oven. Curable resin on the lower glass substrate 12
The bonding method described above, which requires dripping on,
At the same time as the photo-curable resin is dropped onto the lower glass substrate 12, there is a possibility of facing a problem of spreading due to a pressure difference in the surroundings. To consider the spread of such photo-curable resin,
The conventional method requires a blank space for spreading the photocurable resin in the design stage of the liquid crystal display device.

As a result, the effective area of the actual liquid crystal cell is
As shown in FIG. 2, it is limited to the portion of the glass substrate excluding the portion where the photocurable resin has spread. Such restrictions result in a considerable reduction of the glass substrate usage ratio, limiting the number of liquid crystal cells formed on the glass substrate, and increasing the manufacturing cost per cell.

[0012] On the other hand, in order to solve the problem of providing a margin for spreading the photocurable resin by dropping, it has been proposed to use a highly viscous photocurable resin. Even though it prevents the diffusion phenomenon of the photocurable resin and thereby solves the problem of requiring a margin, this method
Cell gap defined between upper and lower glass substrates is usually 5μ
Since it is very small, such as m to 10 μm, when bonding two glass substrates, another problem of cell gap failure is encountered. Furthermore, there is a problem that it becomes difficult to adjust the cell gap.

Therefore, it is an object of the present invention to provide a method of manufacturing a liquid crystal display device, which can increase the use ratio of glass substrates and reduce the ratio of cell gap defects when bonding glass substrates. ..

[0014]

In order to achieve the above object, the present invention provides a step of bonding upper and lower glass substrates having a plurality of liquid crystal cells, and photo-curing in a gap defined between the bonded glass substrates. And a step of irradiating the photocurable resin with ultraviolet rays to cure the resin, and the like.

According to the present invention, the sealing resin dam is provided so as to restrict the photocurable resin from entering the preset range of the bonded glass substrates. A pair of the sealing resin dams is formed on each side edge of the combined glass substrate so as to close the remaining portions of the combined glass substrate except the side edge portions of the combined glass substrate into which the photocurable resin enters.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises the steps of forming a pattern so that a plurality of liquid crystal cells are arranged on upper and lower glass substrates, that is, a pair of large glass substrates facing each other, and bonding the glass substrates facing each other. In addition, the present invention relates to a method for manufacturing a liquid crystal display device, which comprises the steps of cutting the glass substrate and separating the liquid crystal cells from each other, and relates to bonding of glass substrates capable of increasing the effective area of the glass substrates.

In particular, the present invention provides a bonding method for preventing movement of the glass substrate portion after pre-curing each liquid crystal cell arranged between the glass substrates and before pressure curing in the main curing furnace. provide. Compared with the prior art in which a photo-curable resin is dropped before bonding the glass substrates, the bonding method of the present invention combines two glass substrates and then forms a gap defined between the bonded glass substrates. A photocurable resin is added and the photocurable resin is cured.

FIG. 4 illustrates upper and lower glass substrates bonded together to provide a liquid crystal display device according to the present invention. FIG. 5 shows the effective areas of glass substrates bonded together by the bonding method of the present invention. On the other hand, FIG. 6 illustrates a method of injecting a photocurable resin according to the present invention.

A method of manufacturing a liquid crystal display device according to the present invention will be described with reference to FIGS.

Similar to the method described in connection with FIG. 3, the present invention provides alignment films 9 and 9 on upper and lower glass substrates 11 and 12, respectively.
a, a step of applying an epoxy resin sealing material 4a for sealing the liquid crystal cell 4 to the glass substrates 11 and 12 by a silk screen printing method, and a step of pre-curing the sealing material 4a. ing. The glass substrates are accurately positioned and bonded together.

After the glass substrates are bonded, as shown in FIG.
The device 13 for injecting the photocurable resin is attached to the glass substrates 11 and 1
The two side edge portions a, a ′ are set in the vicinity of the preset two side edge portions a, a ′, and then the photocurable resin is injected into the both side edge portions a, a ′ by using air pressure.

The photo-curable resin injected from the injection device 13 has a pressure difference generated between the inside and the outside of the glass substrates 11 and 12 in the gap defined between the joined glass substrates 11 and 12. Enter by the effect of. Then, the photocurable resin is irradiated with ultraviolet rays for curing.

After curing the photo-curable resin, the sealing material 4a
Is pressure cured in the main curing oven. Then, the bonded glass substrates 11 and 12 are cut to form a liquid crystal cell, and then liquid crystal is injected through an injection port. After injecting the liquid crystal, the liquid crystal cell is cleaned by closing the inlet. Polarizing plates 6 and 6a are attached to the outside of the glass substrate of each liquid crystal cell. Thus, the liquid crystal display device is manufactured by the present invention.

According to the above-described method of the present invention, as compared with the conventional method of dropping the photo-curable resin before bonding the glass substrates, after bonding the glass substrates, both side edge portions of the bonded glass substrates are joined together. The effective area of the glass substrate can be increased to accommodate the photocurable resin in the defined gap.

Referring to FIGS. 7A to 7D, there are shown various shapes of the sealing resin dam according to the present invention for limiting the inflow of the photocurable resin to a preset range. According to the present invention, the sealing resin dams 3b, 3b ', 3c and 3c' are provided on both side edges of the glass substrate in order to prevent the photocurable resin from deeply entering the inside of the glass substrate due to its viscosity. The parts are formed in pairs.

By the following method, these sealing resin dams can be formed in the step of applying the sealing material 4a.

That is, a pattern for a sealing resin dam having a desired shape is formed on a silk screen coated with a photosensitive emulsion of 20 μm to 30 μm, which is used in the step of sealing the liquid crystal cell with the sealing material 4a. The silk screen is used as a mask, the silk screen is coated with an epoxy resin and then rubbed using a printing spatula. By rubbing
A seal is formed on the side edge portion of the glass substrate so that the epoxy resin forms a sealing resin dam through the slit of the silk screen.

In this case, the sealing resin dam can be formed into a desired pattern by the exposure and etching methods. Therefore, it is possible to provide various shapes of the sealing resin dam as shown in FIGS. 7A to 7D. 7A to 7D, the sealing resin dam has a closed semi-circular shape, a quadrangular shape, a U-tube shape, and a 90 ° rotation in a portion except both side edges of the glass substrate in which the photocurable resin has entered. It can take various shapes including a U-tube shape.

A pair of sealing resin dams are formed on both side edges of the glass substrate. Each of the sealing resin dams has a width of 0.2 mm to 0.6 mm and a height of 15 μm to 30 μm in the printing step, but is reduced to a range of 6 μm to 8 μm after the glass substrates are bonded and pre-cured. The reduced height matches the cell gap height.

While the preferred embodiment of the invention has been disclosed for purposes of illustration, those skilled in the art will appreciate that various changes, additions and substitutions may be made without departing from the scope and spirit of the invention as disclosed in the appended claims. It will be appreciated that is possible.

[0031]

As is apparent from the above description, the present invention provides the following effects.

First, an increase in the effective area of the glass substrate is achieved, resulting in an improved utilization ratio of the glass substrate and a reduction in manufacturing cost.

Secondly, since the photocurable resin is put into the bonded glass substrate after bonding the glass substrates, the ratio of cell gap defects is reduced, thereby improving the productivity and increasing the cell gap. Can be easily adjusted.

[Brief description of drawings]

FIG. 1 is a plan view of upper and lower glass substrates, which are bonded to each other and provided with a plurality of liquid crystal cells, before cutting by a conventional method.

2 is a schematic plan view showing an effective area of glass substrates bonded to each other according to the conventional method shown in FIG. 1; FIG.

FIG. 3 is a cross-sectional view of a liquid crystal cell manufactured from the glass substrate shown in FIG.

FIG. 4 is a plan view of the upper and lower glass substrates provided with a plurality of liquid crystal cells bonded to each other according to the present invention before cutting.

FIG. 5 is a schematic plan view showing an effective area of glass substrates bonded to each other according to the present invention.

FIG. 6 is a perspective view of a liquid crystal display element portion manufactured from the glass substrate shown in FIG. 4, illustrating injection of a photocurable resin.

7A to 7D are schematic plan views showing various shapes of the sealing resin dam according to the present invention.

[Explanation of symbols]

 3b, 3b ', 3c, 3c' Sealing resin dam 4 Liquid crystal cell 4a Epoxy resin sealing material 5a 6, 6a Polarizing plate 7, 7a, 7b, 7c, 7d Spacer 9, 9a Alignment film 10, 10a Transparent electrode 11, 12 Upper and lower glass substrates 13 Injection device a, a ′ Both side edge portions

Claims (10)

[Claims] 1. A method of manufacturing a liquid crystal display device, comprising the steps of forming a pattern so that a plurality of liquid crystal cells are arranged inside upper and lower glass substrates, and printing a sealing material on one of the glass substrates. Pre-curing the sealing material, facing the glass substrates and bonding them to each other, inserting a photo-curable resin into a gap defined between the bonded glass substrates, A step of irradiating a resin with ultraviolet rays to cure the photocurable resin, a step of curing the sealing material under pressure, a step of cutting the glass substrate to separate it into liquid crystal cells, and forming them in each liquid crystal cell. A liquid crystal display device comprising a step of injecting liquid crystal through the injection port, and a step of sealing the injection port of each liquid crystal cell and attaching a polarizing plate to the outer surface of the glass substrate part of each liquid crystal cell. Manufacturing method. 2. The method for manufacturing a liquid crystal display element according to claim 1, wherein a predetermined range of the glass substrate to which the photocurable resin is bonded is set in the step of printing the sealing material or the step before it. A method for manufacturing a liquid crystal display element, which further includes a step of forming a sealing resin dam for limiting the entry into the inside. 3. The method for manufacturing a liquid crystal display element according to claim 2, wherein the sealing resin dam is formed by a silk screen printing method simultaneously with the printing of the sealing material. Production method. 4. The liquid crystal display device manufacturing method according to claim 2, wherein the sealing resin dams are formed in pairs on both side edge portions of the bonded glass substrates. Manufacturing method of device. 5. The method of manufacturing a liquid crystal display element according to claim 2, wherein the sealing resin dam is made of epoxy sealing resin. 6. The method for manufacturing a liquid crystal display element according to claim 2, wherein the sealing resin dam closes the remaining portions of both side edge portions of the glass substrate except the portion into which the photocurable resin enters. A method of manufacturing a liquid crystal display element, which is formed into a shape. 7. The method of manufacturing a liquid crystal display element according to claim 6, wherein the sealing resin dam is formed in a semicircular shape. 8. The method of manufacturing a liquid crystal display element according to claim 6, wherein the sealing resin dam is formed in a rectangular shape. 9. The method of manufacturing a liquid crystal display element according to claim 6, wherein the sealing resin dam is formed in a U-tube shape. 10. The method of manufacturing a liquid crystal display element according to claim 6, wherein the sealing resin dam is formed in a U-tube shape rotated by 90 °.