JPH0229625A - liquid crystal display element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal display device using a transparent polymer film substrate as a substrate.

2. Description of the Related Art Conventionally, there are liquid crystal display devices of this type as shown in FIGS. 3 and 4. This is each transparent conductive film electrode 1
, 2 formed on the opposing surfaces thereof are placed facing each other with a predetermined interval, and a sealing agent 5 is applied to the periphery of the overlapping portion of both substrates 3 and 4 to seal them together. are adhered to each other, and further, a liquid crystal 7 is sealed between the substrates 3 and 4 through the filling port 6. Here, as the sealant 5, a thermosetting sealant or the like is used. Moreover, electrodes 1 and 2 are IT
O, etc., and the picture electrodes 1 and 2 are connected to the substrates 3 and 4.
are formed so as to face each other in a matrix-like manner within the overlapping region. More specifically, for example, the electrode 1 side is a common electrode (scanning electrode), and the electrode 2 side is a segment electrode (
signal electrode). Furthermore, these electrodes 1, 2
In order to connect to a driving LSI or the like, they are each drawn out to the end surface side of the substrate 3.4 outside the overlapping area of the substrate 3.4 to form lead electrode portions (extracted electrode portions) 8 and 9.

Problems to be Solved by the Invention However, in such a conventional liquid crystal display element, there is a gap 10 where the upper and lower substrates 3 and 4 overlap and face each other in the area outside the sealant 5, which causes various problems. There is.

First, water droplets due to dew condensation or the like may occur and adhere to the minute gap portion 105, especially under high temperature conditions. Due to its electrochemical action, such adhering moisture damages the ITO electrode, especially the lead electrode portion 9 of the lower substrate 4.
This may cause wire breakage or leakage (short circuit) between adjacent electrodes. Due to the occurrence of such defective electrodes, reliability under high temperature and high humidity conditions becomes low.

Furthermore, it is difficult to completely remove the liquid crystal that has entered the gap 10 during the liquid crystal filling process during the manufacturing process, due to changes in the installation environment of the display element and factors over time.

Later, it will come out from time to time, causing dirt, etc.

In particular, when a polymer film substrate 3.4 is used as the substrate, deformation of the display element such as bending due to external stress may cause the substrate 3.
The end portion contacts the substrate 4, causing disconnection of the lead electrode portion 9 on the substrate 4 and an increase in resistance. The occurrence of defective electrodes due to such mechanical contact with the substrate can also occur during the device manufacturing process, and is a cause of lower yield. Furthermore, reliability also decreases.

Here, as a solution to electrode disconnection and short circuits caused by electrochemical factors, a method is proposed in which the application range of the alignment film is extended to the outer area of the sealant, as shown in JP-A-63-8633, and JP-A-62-8633. As shown in Japanese Patent No. 194230, there is a method in which the gap is filled with an ultraviolet curable resin that does not contain an organic solvent. However, both methods have problems such as an increase in the number of man-hours and the occurrence of defective electrodes during resin filling, and furthermore, there is a problem that the alignment film has a decrease in mechanical strength.

Means for Solving the Problem In a liquid crystal display element, two transparent polymer film substrates, each having a transparent conductive film electrode formed thereon, are placed facing each other at a predetermined distance and are bonded together with a sealant, with liquid crystal sealed between the substrates. The two substrates are bonded together using a sealant at the outermost periphery of the periphery of the overlapping portion of the two substrates.

Both substrates made of working polymer film substrates are adhered by a sealant at the outermost periphery of the overlapping portion, so that there is no place where the substrates overlap and face each other outside the sealant. That is, there is no gap as in the conventional case, and defects such as breakage of the lead electrode portion due to electrical or mechanical factors are prevented.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. The same parts as those shown in FIGS. 3 and 4 are indicated using the same reference numerals. In this embodiment, the basic structure itself is similar to the conventional one, but the position of the sealant 5 for bonding the polymer film substrates 3 and 4 is changed to the outermost periphery of the overlapping portion of these substrates 3 and 4. This is the location. That is, the outer end face of the sealant 5 is aligned with the end face of the substrate 3 and the end face of the substrate 4, so that no gap is formed outside the sealant 5 due to the overlapping of the two substrates 3 and 4.

Here, as the sealant 5, for example, a thermosetting sealant is used.

By adopting such a liquid crystal sealing structure, for example, even if a burr or the like occurs at the edge of the upper substrate 3 due to cutting, the sealing agent 5 is present under that portion, and the upper and lower substrates 3. When stacking the substrates 4 on top of each other, the substrates 4 do not come into direct contact with the lower substrate 4 side.

Therefore, the lead electrode portion 9 of the substrate 4 below does not suffer from defects such as disconnection due to mechanical factors such as contact with the edge of the substrate 3. Therefore, the yield is improved. Furthermore, even if external stress etc. may be applied after the bonding process, there is no contact between the substrates 3 and 4, and electrode failures such as electrode breakage due to mechanical factors do not occur, making it highly reliable. Become. Moreover, since there is no gap between the substrates 3 and 4 on the outside of the sealant 5, there is no penetration of the liquid crystal to the outside of the liquid crystal cell due to capillary action when the liquid crystal is sealed. Furthermore, even under high temperature and high-temperature conditions, if there is a gap, there may be adhesion of moisture, or electrochemical melting of the ITO electrode (lead electrode parts 8, 9) due to this moisture, resulting in disconnection or adhesion of moisture. This also solves the problem of leakage between adjacent electrodes. Therefore, it becomes highly reliable.

Effects of the Invention In the present invention, as described above, both substrates are bonded at the outermost periphery of the overlapping portion of the substrates using a sealant, so that there is no overlap between the two substrates on the outside of the sealant. Therefore, problems such as electrochemical electrode failures caused by gaps and electrode failures due to mechanical contact can be solved, reducing electrode disconnection and high resistance, and improving the performance of liquid crystal display elements. Yield can be improved and reliability can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a plan view, FIG. 3 is a plan view showing a conventional example, and FIG. 4 is a sectional view.

Claims (1)

[Claims] In a liquid crystal display element in which two transparent polymer film substrates, each having a transparent conductive film electrode formed thereon, are opposed to each other at a predetermined distance and are bonded together with a sealant, and a liquid crystal is sealed between the substrates, the overlapped portion of the two substrates is A liquid crystal display element characterized in that both substrates are bonded to each other with a sealant at the outermost periphery of the periphery.