JPS5875114A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To prevent stripping of sealed parts with respect to a liquid crystal element wherein plastic films are used for upper and lower substrates by adhering the peripheral part of the upper and lower substrates via a sealing material and further adhering the corner parts double. CONSTITUTION:PET films of thermoplastic resins are used for an upper substrate 1 and a lower substrate 2. Electrodes 6 of indium oxide films are provided and polyamide films 7 are formed thereon and are rubbed to make oriented films. A polyester adhesive 8 is coated on the peripheral part of the substrate 1 and a sealing port 10 is provided. The substrates 1, 2 are adhered with the agent 8 via glass fibers 9 which are spacers. Thereafter the corner parts of the substrates 1, 2 are melt-stuck with an ultrasonic heater to provide melt-stuck parts 8 whereby the substrates are adhered double and reinforced. A liquid crystal 3 is injected therebetween to provide the liquid crystal display element made of synthetic resins.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a liquid crystal display element, and particularly to a method for manufacturing a liquid crystal display element.

The present invention relates to a method of manufacturing a liquid crystal display element suitable for using a plastic film as a substrate.

The liquid crystal display element has an upper substrate 1 and a lower substrate 2 as shown in FIG.
The two substrates are stacked one on top of the other at a constant interval, and a liquid crystal 3 is sealed between the upper and lower substrates.

The peripheries of the upper and lower substrates are sealed with an adhesive.

The seal portion is indicated by 4.

An element using a glass plate as a substrate does not deform even if some external force is applied to the element, but when a plastic film is used as a substrate, it easily deforms due to the film's flexibility.

At this time, if the adhesiveness of the seal part is weak, the seal will peel. As shown in FIG. 2, seal peeling often begins at a part of the corner of the seal area (area marked with ζ20). This is because stress tends to concentrate.

The object of the present invention is to particularly strengthen the adhesion of the corners of the sealing part, thereby preventing the seal from peeling even when the element is subjected to heat cycles or is subjected to stress during handling. The purpose is to provide a single element.

FIG. 3 is a diagram showing an embodiment of the present invention. 1. When the plastic film is a thermoplastic film such as polyethylene terephthalate (PET) film or trifluorochloroethylene film, it is possible to heat-fuse the films together. The upper and lower substrates are spot-fused together at a part of the corner of the housing. The fused portion is indicated by 5. (b) is a sectional view taken along line AA' in (a).

Since the upper and lower substrates 1 and 2 are integrated at the fused portion, mechanical strength is greatly improved.

The third case when a 200 μm thick PET film is used as a substrate
The manufacturing method shown in the figure is shown below. After forming an indium oxide film electrode 6 on the film surface by vapor deposition.

After a polyamide film 7 is applied and dried, a rubbing treatment is performed. Apply Bo+t% ester adhesive 8 to the periphery of the upper substrate 10.
After dispersing glass fibers 9 with a diameter of 10 μm on the alignment film surface of the lower substrate 2 so that the distance between the upper and lower substrates is 10 μm, the upper substrate 1 is placed on top of the 100C
Pressure was applied to adhere the upper and lower substrates.

Next, use an ultrasonic heating device to
The lower substrates were heat-fused together. The fused portion is indicated by 5-. Thereafter, liquid crystal was sealed through the filling port 10.

Note that the fusion may be performed after the liquid crystal is sealed.

The device of the present invention undergoes a heat cycle (-30'-+80'
C) It was confirmed that no seal peeling occurred even in response to the stress applied to the element during testing or mounting on calculators, watches, etc.

FIG. 4 is a diagram showing another embodiment of the present invention.

If the substrate is a film other than thermoplastic, heat fusion as shown in FIG. 3 is impossible. To transparency.

When a film made of excellent epoxy resin is used as a substrate, epoxy adhesive is applied to the upper and lower substrates and cured after forming the device in a part of the corner of the seal area as shown in Figure 4. to improve adhesion between substrates.

The adhesive layer is shown in 11.

In the case of PET film, the method shown in FIG. 4 can be employed if a polyester adhesive is used instead of heat fusing.
1 The present invention improves the adhesion of some corners of the seal area of the device where seal peeling is most likely to occur, so it is less susceptible to temperature changes such as heat cycles and stress during handling. This has the effect that it is possible to obtain a liquid crystal display element using a highly reliable plastic film as a substrate, which does not cause seal peeling or peeling.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a liquid crystal display element, FIG. 2 is a diagram showing peeling of the seal part of the element, FIG. 3 is a diagram showing one embodiment of the present invention, and FIG. 4 is a diagram showing another embodiment of the present invention. It is a figure showing an example. 1... Upper substrate, 2... Lower substrate, 3... Liquid crystal, 4...
... Seal part, 5... Fusion part, 6... Indium oxide film electrode, 7... Polyamide film, 8... Adhesive,
9...Glass fiber, 10...Enclosure port, 11
...Adhesive layer for reinforcement. 'M1 drawing 2 drawing

Claims (1)

[Claims] 1. In a device in which a liquid crystal is held between a pair of plastic films with electrodes formed on opposing surfaces and the pair of plastic films are sealed with a sealing material, the area to be sealed is A method for manufacturing a liquid crystal display element, characterized in that at least some of the corners thereof are double bonded. 2. A method for manufacturing a liquid crystal display element according to claim 1, characterized in that at least a portion of a corner of the sealed area is heat-fused. 3. A method of manufacturing a liquid crystal display element according to claim 1, characterized in that an adhesive is applied to at least a portion of a corner of the sealed area and cured.