JPH0990378A - Method for joining substrate and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a liquid crystal display device with which the gap between substrates is made uniform. SOLUTION: Two sheets of the substrates 2, 3 are superposed on each other via sealing materials formed by printing, etc., on either one of these substrates 2, 3. The two substrates 2, 3 superposed on each other are arranged on a table 1 and are pressurized by pressing the four pressurizing parts 4a to 4d of a pressurizing plate 4 thereto from above the upper substrate 3. The pressurizing plate 4 is heated, by which the two substrates 2, 3 are stuck to each other. In such a case, the four pressurizing parts 4a, to 4d of the pressurizing plate 4 respectively pressurize the corresponding parts of the substrates 2, 3 and, therefore, even if the substrates are large in size or are nonuniform in the material quality of the sealing materials and coating by the printing, etc., the respective prescribed points of the substrates 2, 3 are uniformly pressurized and the variation in the gap between the substrates 2, 3 by the misalignment and unequal pressurization of the substrates 2, 3 is prevented. The gap between the substrates 2, 3 is thus made more uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate bonding method and an apparatus thereof, and more particularly to a substrate bonding method and an apparatus thereof used for manufacturing a liquid crystal display device.

[0002]

2. Description of the Related Art In a liquid crystal display device, two transparent substrates each having a transparent electrode and an alignment film provided on opposite surfaces thereof are bonded to each other with a sealing material interposed between the two substrates inside the sealing material. It has a structure in which liquid crystal is enclosed.

By the way, when manufacturing such a liquid crystal display device, two substrates are bonded together via a sealing material. In this case, two substrates are superposed on each other via a sealing material formed by printing on one of the two substrates, and the two superposed substrates are placed on a table.
The two substrates are bonded by pressing a pressure plate from above the upper substrate and heating while applying pressure.

[0004]

However, in the conventional method for manufacturing such a liquid crystal display device, the central portion of the pressure plate is pressurized, and this pressure acts on both substrates via the pressure plate. Therefore, if the substrate becomes large or the material of the sealing material or the coating due to printing becomes uneven, the pressing force acting on each part of the substrate tends to become uneven. In such a case, there is a problem in that misalignment and unevenness in pressure occur in the substrates, the gaps between the substrates become non-uniform, and the quality deteriorates. An object of the present invention is to provide a substrate bonding method and a device therefor capable of stably obtaining a uniform gap over the entire substrate.

[0005]

According to the first aspect of the present invention,
A substrate joining method for joining a pair of substrates in a state in which a predetermined gap is held via a frame-shaped sealing material, wherein a main plane of the pair of substrates superposed via the sealing material is provided with a plurality of pressing regions. And pressure is adjusted at the same time for each of the pressure areas to bond the pair of substrates in a state in which a predetermined gap is uniformly held over the entire area. Is. According to a second aspect of the present invention, there is provided a substrate bonding apparatus for bonding a pair of substrates with a frame-shaped sealing material in a state in which a predetermined gap is maintained, the pair of substrates being superposed with each other with the sealing material interposed therebetween. A plate that supports the substrate and a plurality of pressurizing units that can individually adjust the pressure, while adjusting the individual pressures in the direction of compressing the gap between the pair of substrates supported by the plurality of pressurizing units. And a pressure plate that simultaneously applies pressure.

According to the present invention, since the plurality of pressurizing portions of the pressurizing plate press the corresponding portions of the two substrates superposed on each other via the sealant, the substrate is large or the sealant is used. Even if the material is uneven or the coating is uneven due to printing, etc., it is possible to prevent variations in the gap between the substrates due to misalignment of the substrates and uneven pressure, and to obtain a uniform gap over the entire substrate in a stable manner. You can in this case,
According to a third aspect of the present invention, the pressure plate includes a cushioning member made of a flexible material, and a pressing plate that presses the pair of substrates via the cushioning member. If it is divided into a plurality of corresponding pressure parts, the plurality of pressure parts can individually press the corresponding parts flexibly according to the state,
The variation in the gap between the substrates can be suppressed more effectively.

[0007]

1 shows a method of manufacturing a liquid crystal display device according to a first embodiment of the present invention. Therefore, a method of manufacturing a liquid crystal display device will be described with reference to this drawing. First, the lower substrate 2 is placed on the upper surface of the table 1, and the upper substrate 3 is positioned and stacked on the lower substrate 2. In this case, a sealing material (not shown) is formed on one of the two substrates 2 and 3 by printing or the like. The sealing material is mainly composed of an epoxy resin and the like, alumina (aluminum oxide), silica (silicon oxide) particles and the like are blended as a secondary material, and a carbitol-based organic solvent or the like is used as a solvent. The viscosity is 400 ± 100 P, the nonvolatile content is 87 to 93 wt%, and the thixo ratio (T.I value) is 1.2 to 2.0.

A pressure plate 4 is arranged above the table 1. The pressure plate 4 is a metal plate 5 made of aluminum or the like in which a heater (not shown) is embedded.
And a cushioning member 6 made of silicon sponge or the like provided on the lower surface of the metal plate 5, and a release sheet 7 made of fluororesin provided on the lower surface of the cushioning member 6. The pressurizing plate 4 is divided into four pressurizing parts 4a to 4d so as to be divided into equal parts, and respective central parts of the pressurizing parts 4a to 4d are pressed by a pressurizing means (not shown). ing.

Next, the pressure plate 4 is lowered to press the two substrates 2 and 3 superposed on each other with the seal material interposed therebetween from the both surface sides thereof with the upper surface of the table 1 and the lower surface of the pressure plate 4. At the same time, when the pressure plate 4 is heated, the two substrates 2 and 3 are attached to each other via the sealing material. in this case,
The four pressure units 4a to 4d of the pressure plate 4 are connected to the substrates 2 and 3.
Since the respective corresponding portions are pressed, even if the substrates 2 and 3 are large or the material of the sealing material or the application due to printing is uneven, the entire substrates 2 and 3 can be pressed almost uniformly. Therefore, it is possible to prevent variations in the gap between the substrates 2 and 3 due to misalignment of the substrates 2 and 3 and uneven pressure, and it is possible to stably obtain a uniform gap between the substrates 2 and 3. As a result, there is no deterioration in quality due to non-uniformity of the gap between the substrates 2 and 3. Moreover, since the viscosity of the sealing material is 400 ± 100P, which is smaller than the viscosity (600 ± 100P) of the conventional sealing material, it is more likely to be deformed than the conventional sealing material when pressed, and lower than the conventional Both substrates 2 and 3 can be bonded together by pressure, and the misalignment of the substrates 2 and 3 can be prevented.

In the first embodiment, the epoxy resin (thermosetting resin) is used as the sealing material, but the sealing material is not limited to this and may be an ultraviolet curing resin. In this case, for example, if the table 1 is made of a transparent material and the lower surface is irradiated with ultraviolet rays, the sealing material is cured, so that heating is not necessary.

FIG. 2 shows a method of manufacturing a liquid crystal display device according to the second embodiment of the present invention. In this figure, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted as appropriate. The pressure plate 11 used in this embodiment includes four metal plates 12a to 12 made of a metal such as aluminum having heaters embedded therein.
d, a single thin plate 13 made of aluminum or the like having a thickness of about 2 mm, which is provided over the entire lower surface of each metal plate 12a to 12d, and a cushioning member 6 made of silicon sponge provided on the lower surface of the thin plate 13. , A release sheet 7 made of fluororesin or the like provided on the lower surface of the cushioning member 6. Each metal plate 12 is attached to the pressure plate 11.
Four pressing portions 11a to 11d are formed, in which the respective central portions of a to 12d are pressed by pressing means (not shown). Thus, the metal plate 1 of the pressure plate 11
Since 2a to 12d are divided into four, each of the four pressurizing portions 11a to 11d can flexibly press the corresponding portion individually according to the state, and the variation in the gap between the substrates 2 and 3 is more effective. Can be suppressed. Also, each metal plate 1
Since one thin plate 13 is provided over the entire lower surface of 2a to 12d, it is possible to prevent uneven pressing due to the edge portions of the metal plates 12a to 12d.

In the above first and second embodiments,
Although four pressurizing parts 4a to 4d (11a to 11d) are provided,
The invention is not limited to this, and may be provided depending on the areas of the substrates 2 and 3. The substrates 2 and 3 may be either one substrate for forming one liquid crystal display device or one base substrate for forming a plurality of liquid crystal display devices.

[0013]

As described above, according to the present invention, the plurality of pressurizing portions of the pressurizing plate press the corresponding portions of the two superposed substrates via the sealing material, respectively. Even if the seal material is large or the coating is uneven due to printing, the gap between the substrates due to misalignment of the substrates and uneven pressure is prevented, and the gap between the substrates is uniform. A stable gap can be obtained. In this case, as in the invention according to claim 3,
The pressure plate includes a buffer member made of a flexible material, and a pressing plate that presses the pair of substrates via the buffer member,
Since this pressing plate is divided into a plurality of parts corresponding to the plurality of pressing parts, each of the plurality of pressing parts can flexibly press the corresponding part individually according to the state, and the variation of the gap between the substrates can be prevented. It can be suppressed more effectively.

[Brief description of drawings]

FIG. 1 is a perspective view showing a method of manufacturing a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a method of manufacturing a liquid crystal display device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 table 2, 3 substrate 4, 11 pressure plate 4a-4d, 11a-11d pressure part 5, 12a-12d metal plate 6 cushioning member

Claims (3)

[Claims] 1. A substrate bonding method for bonding a pair of substrates with a frame-shaped sealing material while maintaining a predetermined gap, wherein a main plane of the pair of substrates stacked with each other through the sealing material is formed. Partitioning into a plurality of pressure areas, simultaneously applying pressure while adjusting the pressure for each of the pressure areas, and joining the pair of substrates in a state in which a predetermined gap is uniformly held over the entire area. A method for joining substrates, the method comprising: 2. A substrate joining apparatus for joining a pair of substrates with a frame-shaped sealing material in a state where a predetermined gap is maintained, the pair of substrates being supported by the sealing material. And a plurality of pressurizing units whose pressures can be individually adjusted, and simultaneously pressurizes the pair of substrates supported by the plurality of pressurizing units in the direction of compressing the gap while adjusting the individual pressures. A substrate bonding apparatus having a pressure plate. 3. The pressure plate includes a cushioning member made of a flexible material, and a pressing plate that presses the pair of substrates via the cushioning member. The pressing plate includes a plurality of pressing portions. The substrate bonding apparatus according to claim 2, wherein the substrate bonding apparatus is divided into a plurality of parts corresponding to the above.