JPH0128363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for assembling a liquid crystal display cell in which a pair of transparent electrode plates sandwiching a sealant are pressurized and adhesively fixed in a uniform gap between the electrode plates.

As a method for manufacturing a liquid crystal display element, a thermosetting adhesive is printed on one electrode plate in a desired shape by screen printing, and the electrode plate is pre-dried to harden the thermosetting adhesive. Then, the electrode plates are sandwiched between the other electrode plates, and the electrode plates are placed in a high-temperature oven under pressure to soften and then harden the thermosetting adhesive, which is then adhesively fixed, thereby creating a space between the electrode plates. There is a method of manufacturing a liquid crystal display element by injecting liquid crystal into the liquid crystal. A liquid crystal display cell used in such a liquid crystal display element is manufactured by printing a sealant 2 on one transparent electrode plate 1 and overlapping the other electrode plate (not shown), as shown in FIG. Formed by adhesive fixation. The sealant 2 is made by mixing an epoxy-based thermosetting adhesive 3 with a glass fiber 4 for controlling the gap between the electrode plates (hereinafter referred to as gap), and the height of the sealant 2 printed on the electrode plate is is approximately 25 μm. The assembly of this liquid crystal display cell is
Conventionally, as shown in FIG. 2, two electrode plates 1 with a sealant 2 sandwiched between them are manually pressurized using clips 5 and placed in a curing oven at 150°C or higher for 1 to 2 hours. One method used to do this was to leave the sealant 2 to deform and then fix it with adhesive to obtain a proper gap. As another method of applying pressure, as shown in FIG. There is a way to pressurize. According to experiments conducted by the inventors of the present application, in order to deform the sealant and obtain a uniform gap, a pressure of 3 kg or more is required for one pattern, and the sealing portion is Pressure must be applied uniformly over the entire surface. Therefore, in order to manufacture a large number of liquid crystal display cells in one assembly, a large number of patterns are created on the large electrode plate 8, and the sealant 2 is applied in a sandwich-like manner, as shown in FIG. When applying pressure to a multi-layered stack of large electrode plates 8 sandwiched between them, the required pressing force increases, making it extremely difficult to apply pressure using clips or weights. For example, the pressure required to assemble a large electrode plate with 24 patterns is approximately 72
However, it is extremely difficult to apply such pressure manually using clips and to apply uniform pressure to the sealant of each liquid crystal display cell. Furthermore, the pressurizing method using weights has the disadvantage that the weights are very heavy and the workability of carrying the material into the curing furnace is very poor.

Furthermore, as described in JP-A No. 53-91763, a flexible sheet is attached to the upper holding plate and the cells are compressed by fluid pressure through the sheet, which applies pressure uniformly on the cell surface. However, the fluid pressure must be controlled by controlling a valve connected to a pressure source, which results in a large device and poor workability.

An object of the present invention is to provide a method and apparatus for manufacturing a liquid crystal display cell that eliminates the drawbacks of the prior art described above, has good workability, and can stably bond under heat. In order to achieve this object, the present invention installs a plurality of liquid crystal display cells under a frame, installs a presser plate on the liquid crystal display cells, and installs a low pressure side cylinder on the presser plate. A pressing means consisting of a high pressure side cylinder is installed,
High-pressure air is introduced into the high-pressure side cylinder from a fluid coupling, the liquid crystal display cell is pressurized by air pressure, the fluid coupling is sealed, and the liquid crystal display cell is heated in an atmosphere at a predetermined temperature. As the sealant of the liquid crystal display cell deforms and the presser plate descends, the pressure generated by the expansion of air in the sealed high-pressure side cylinder is used to maintain approximately the same pressure on the liquid crystal display cell. The feature is that the liquid crystal display cell is crimped. This assembly device adhesively fixes large electrode plates with the desired gap accuracy.
The product is left in a curing oven at 150°C or higher for 1 to 2 hours. In the assembly device of the present invention, by using a rubber bellows as a pressurizing method, the sealant deforms as the temperature rises during curing, and the presser plate descends. Since the pressure increases, uniform pressure can always be applied to the sealant. A concrete example of this is as follows. The device for manufacturing a liquid crystal display cell according to the present invention is carried into a curing furnace, and the temperature is 20°C (absolute temperature
293K) to 180℃ (453K), the equation of state PV=nRT (where P is pressure, V is volume,
n is a constant, R is a gas constant, and T is an absolute temperature), and the volume V inside the cylinder is constant, P ₂ = P ₁ ×T ₂ /T ₁ = 1.55 × P ₁ . In other words, the pressure inside the cylinder will increase by 55% due to the temperature increase. Assuming that the initial pressure in the high pressure cylinder is 4 atm and the initial pressure in the low pressure cylinder is 1 atm, at 180°C, the pressure in the high pressure cylinder is 6.2 atm and the pressure in the low pressure cylinder is 1.6 atm. At 20°C, the difference between the pressure in the high-pressure side cylinder and the pressure in the low-pressure side cylinder was 3 atm, but at 180°C, the difference becomes 4.6 atm, and the pressure difference increases by 1.6 atm. This compensates for the pressure drop caused by the deformation of the sealant, and the pressure is applied to the cell in a substantially constant manner. In addition, if the low pressure side cylinder is not sealed and left open to the same pressure as atmospheric pressure, the temperature will rise to 180°C.
The difference between the pressure in the high-pressure cylinder and the pressure in the low-pressure cylinder at
Similarly to the above, the pressure on the cell can be kept almost constant. Furthermore, since the pressurization is performed using an air spring, it is lightweight and can apply a large amount of pressurizing force.Also, by using a double-way opening/closing fluid coupling in the air insertion hole on the high pressure side, it can be applied instantly. It is possible to add or remove pressure.

Next, one embodiment of the present invention will be explained in detail with reference to the drawings. FIG. 5 shows an assembly apparatus of this embodiment, which presses large electrode plates 8 stacked in multiple layers through spacers 6 made of elastic material. This assembly device includes a rubber bellows 11 made of silicone rubber attached between a high-pressure side cylinder 9 and a low-pressure side cylinder 10, and a rubber bellows 11 on the low-pressure side that moves a presser plate 13 up and down via the low-pressure side cylinder 10 and a spring 12. A piston rod 14 connected to the cylinder 9, a fluid coupling 15 of a double-way opening/closing type that is attached to the high-pressure side cylinder 9 and instantly sucks and exhausts high-pressure air, and a large electrode plate 8 that supports the cylinder section and is installed in a multilayered manner. It consists of a pedestal 16. The operation will be described below. Large electrode plates 8 sandwiching sealant 2 are stacked in multiple layers with spacers 6 interposed therebetween, and installed on a pedestal 16. Next, high pressure air is introduced from the fluid coupling 15, the presser plate 13 is lowered, and the sealant 2 between the large electrode plates 8 is pressurized with a set pressure, and then the fluid coupling 15 is sealed. Next, this assembly equipment is heated to
The sealant 2 is left in a curing oven (not shown) at 180° C. for 2 hours to deform the sealant 2 to form the required gap, and the large electrode plate 8 is adhesively fixed. Next, the assembly device is taken out of the curing furnace, the fluid coupling 15 is opened, and the spring 12
By raising the presser plate 13 by the action of
The large electrode plate 8 adhesively fixed with the sealant 2 can be taken out.

An actual example using the assembly apparatus according to the present invention will be described below. A sealant containing 10 μm diameter glass fibers for gap control was printed on one large electrode plate on which 24 liquid crystal display patterns were formed, and overlapped with the other large electrode plate. The gap at this time is approximately 25 μm. Large electrode plates sandwiched with this sealant were stacked in multiple layers, pressurized with an air pressure of 4 atmospheres (approximately 160 kg of pressure), and left in a curing furnace. As a result, a stable gap accuracy of 10 μm±2 μm was obtained for each element.

As described above, according to the present invention, in an assembly apparatus for a liquid crystal display cell, pressurizing force is applied by high-pressure air using an air spring bellows to a presser plate corresponding to a large electrode plate, and a double-circuit opening/closing type fluid is applied. Since the joint instantly seals while maintaining the above pressure, the assembly equipment is lightweight and can apply a large amount of pressurizing force, improving work efficiency such as transporting to the curing furnace. As the presser plate lowers due to the deformation of the sealant, the pressurizing force increases due to air expansion in the high-pressure side cylinder, so a uniform pressurizing force can be applied at all times. Therefore, according to the present invention, large electrode plates with multiple patterns can be stacked in multiple layers and uniformly applied with a pressure of 100 kg or more, which was extremely difficult with conventional pressurization methods using clips or weights. Pressing can also be carried out easily and with good workability.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a cell with a conventional liquid crystal display pattern, and FIGS. 2 and 3 are side views showing an assembly apparatus for the conventional cell as shown in FIG. Figure 4 is a plan view showing an example of a cell in which multiple patterns are formed on a large electrode plate;
The figure is a side view showing an embodiment of a liquid crystal display cell assembly apparatus according to the present invention, which is intended for large-sized electrode plates stacked in multiple layers. Explanation of symbols, 1...electrode plate, 2...sealant, 3...
Thermosetting adhesive, 4... Glass fiber, 5... Clip, 6... Spacer, 7... Weight, 8... Large electrode plate, 9... High pressure side cylinder, 10... Low pressure side cylinder, 11... Rubber bellows, 12... Spring, 13... Holding plate, 14... Piston rod, 15... Fluid coupling,
16... mount.

Claims (1)

[Claims] 1. A liquid crystal display cell is formed by sandwiching an adhesive sealant between a pair of opposing transparent electrode plates, and a plurality of the liquid crystal display cells are stacked and placed on a pedestal. A presser plate is installed on top of the liquid crystal display cell, and a pressing means consisting of a low-pressure side cylinder and a high-pressure side cylinder having a fluid coupling for introducing high-pressure air is installed on the presser plate. High-pressure air is introduced from the joint, and the liquid crystal display cell is pressurized at a predetermined pressure via the presser plate by the pressure from the pressing means, the fluid joint is sealed, and the liquid crystal display cell is placed in an atmosphere at a predetermined temperature. When heated, the sealant deforms, and as the presser plate descends, the pressure generated by air expansion in the sealed high-pressure side cylinder keeps the pressure applied to the liquid crystal display cell almost the same. A method for manufacturing a liquid crystal display cell, characterized in that the liquid crystal display cell is pressure-bonded. 2. The method of manufacturing a liquid crystal display cell according to claim 1, wherein the liquid crystal display cells are stacked with spacers interposed therebetween. 3. The method for manufacturing a liquid crystal display cell according to claim 1, wherein the sealant is an epoxy thermosetting adhesive mixed with glass fiber. 4. A laminated liquid crystal display cell made by stacking a plurality of liquid crystal display cells with an adhesive sealant sandwiched between a pair of opposing transparent electrode plates, and a presser plate for holding down the liquid crystal display cells. , a low-pressure side cylinder installed on the presser plate, a piston rod provided in the low-pressure side cylinder that contacts the presser plate, and a spring provided inside the low-pressure side cylinder for moving the presser plate in the vertical direction. a high-pressure side cylinder provided on the low-pressure side cylinder; a fluid coupling that intakes and exhausts high-pressure air into the high-pressure side cylinder and seals the inside of the high-pressure side cylinder before heating the liquid crystal display cell; The high-pressure side cylinder and the low-pressure side cylinder apply pressurizing force to the presser plate through the piston rod and provide air pressure when the air in the high-pressure side cylinder sealed by the fluid joint expands due to temperature rise. 1. An apparatus for manufacturing a liquid crystal display cell, comprising an air spring bellows provided between the bellows and a pedestal on which the liquid crystal display cell is installed. 5. The apparatus for manufacturing a liquid crystal display cell according to claim 4, wherein the liquid crystal display cells are stacked with spacers interposed therebetween. 6. The device for manufacturing a liquid crystal display cell according to claim 4, wherein the sealant is an epoxy thermosetting adhesive mixed with glass fiber.