JPH0532736B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rectangular (square) liquid crystal display device using a flexible substrate such as a thermoplastic plastic film such as polyethylene terephthalate film or trifluorochloroethylene film. Person in charge,
In particular, the present invention relates to liquid crystal display elements suitable for display devices such as calculators and watches.

As shown in FIG. 1, a liquid crystal display element is assembled by stacking an upper substrate 1 and a lower substrate 2 at a constant interval, and sealing a liquid crystal 3 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, peeling of the seal will occur.

At this time, such display elements are generally made in a square shape such as a rectangle, and therefore, as shown in Fig. 2, this seal peeling occurs at the corners of the seal area ( The area shown in ) is often the starting point. This is because stress tends to concentrate.

The object of the present invention is to provide an element that does not cause seal peeling even when the element is subjected to a heat cycle or is subjected to stress during handling, by particularly strengthening the adhesiveness of the corner parts of the seal part. There is something to do.

FIG. 3 is a diagram showing an embodiment of the present invention. 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 the corners of the seal portion. 5 the fused part
Indicated by Figure b is a sectional view taken along line A-A' in figure a.
Since the upper and lower substrates 1 and 2 are integrated at the fused portion, mechanical strength is greatly improved.

The manufacturing method shown in Fig. 3 using a 200 μm thick PET film as the substrate is shown below. After forming an indium oxide film electrode 6 on the film surface by vapor deposition, a polyamide film 7 is applied, dried, and then rubbed. A polyester adhesive 8 is applied to the periphery of the upper substrate 1, and a glass fiber 9 with a diameter of 10 μm is placed on the alignment film surface of the lower substrate 2 as a spacer so that the gap between the upper and lower substrates is 10 μm. After dispersing, stack the upper substrate 1 and apply pressure at 100℃ to
Glued the bottom board.

Next, using an ultrasonic heating device, the upper and lower substrates were heat-fused together at the corner portions. 5 the fused part
Indicated by Thereafter, liquid crystal was sealed through the filling port 10. Note that the fusion may be performed after the liquid crystal is sealed.

Therefore, in the liquid crystal display element according to the embodiment of the present invention shown in FIG.
Since the fused portion 5 is also provided, the mechanical strength of the corner portion can be greatly improved.

The liquid crystal display device according to the embodiment shown in FIG. It was confirmed that no peeling of the seal occurred even when

The present invention improves the adhesion of the corners of the seal area of the device where seal peeling is most likely to occur, so the seal remains intact even when subjected to temperature changes such as heat cycles or stress during handling. This has the advantage that it is possible to obtain a liquid crystal display element whose substrate is a highly reliable plastic film that does not peel off.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a liquid crystal display element, FIG. 2 is a diagram showing peeling of a seal portion of the element, and FIG. 3 is a diagram showing an embodiment of the present invention. 1... Upper substrate, 2... Lower substrate, 3... Liquid crystal, 4
. . . Seal portion, 5 . . . Fusion portion, 6 .

Claims (1)

[Scope of Claims] 1. A pair of rectangular flexible films made of a thermoplastic material having electrodes formed on overlapping opposing surfaces, the peripheral portions of which are firmly sealed with a sealing material, and the pair of rectangular flexible films In a rectangular liquid crystal display element in which a liquid crystal is sealed in a space formed between overlapping opposing surfaces of a pair of rectangular flexible films, the inside of the fixed sealing portion formed by the sealing material at the corner portion existing around the periphery of the pair of rectangular flexible films. A liquid crystal display element characterized in that, independently of the fixed and sealed part made of the sealing material, a fused part formed by local heating of the pair of flexible films is provided. 2. The liquid crystal display element according to claim 1, wherein the space portion is formed by fibrous spacers distributed on opposing surfaces of the pair of flexible films.