JPH0511262A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display element which is decreased in the electrostatic capacity of its dummy electrode, high in excellent article yield and superior in durability. CONSTITUTION:Plural dummy electrodes 14 are formed divisionally in each non-display area 10 which is on the internal surface of an upper electrode substrate 2 or lower electrode substrate 4 and where an upper transparent electrode 1 and/or a lower transparent electrode 3 is not formed. The shape, array, etc., of the dummy electrodes 14 can optionally be designed. Further, the size of the dummy electrodes 14 can optionally be set in consideration of the electrostatic capacity, etc., and equalized, specially preferably, to the size of one picture element in a display area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to the shape and arrangement of dummy electrodes formed in a non-display area.

[0002]

2. Description of the Related Art A liquid crystal display device, as shown in FIG. 5, includes an upper electrode substrate 2 having an upper transparent electrode 1 formed on one surface and a lower electrode substrate 4 having a lower transparent electrode 3 formed on one surface thereof.
The transparent electrodes 1 and 3 are placed inside, and the transparent electrode formation surfaces of the electrode substrates 2 and 4 are bonded to each other via a predetermined cell gap G, and a liquid crystal (not shown) is enclosed in the cell gap G. At the same time, an upper polarizing plate 5 and a lower polarizing plate 6 are provided on the outer surface of each of the electrode substrates 2 and 4. Generally, a liquid crystal display element is required to have a high cell gap accuracy.
TN (Super Twisted Nematic) type and full color TFT
An extremely high cell gap accuracy of ± 0.1 μm or less is required for a (Thin Film Tran-sistor) type liquid crystal display device, and ± 0.05 μm or less for a multi-tone black and white liquid crystal display device.

By the way, as shown in FIG. 6, an upper transparent electrode 1 and a lower transparent electrode 3 are arranged orthogonally to each other, and the upper transparent electrode 1 and the lower transparent electrode 3 are divided into a plurality of groups, which are different from each other. Flexible boards 7a, 7
driver ICs 8a, 8 mounted on the terminals b, 7c, ...
In the dot matrix type liquid crystal display element connected to the output terminals b, 8c, ...
In order to facilitate the attachment of a, 7b, 7c, ..., In general, the end portions of each transparent electrode group are aggregated and drawn to the end portions of the upper electrode substrate 2 or the lower electrode substrate 4,
It is connected to the electrode terminal 9. Therefore, the first driver I
Between the first transparent electrode group 1a connected to C8a and the second transparent electrode group 1b connected to the second driver IC 8b arranged adjacent to the first driver IC 8a, and the liquid crystal display element. A non-display area 10 having no transparent electrode is formed on the outermost part of the. Incidentally, reference numeral 11 in the drawing
Is a lead pattern formed on the flexible substrates 7a, 7b, 7c, ..., and reference numeral 12 is a printed wiring board on which a circuit pattern 13 for driving a liquid crystal display element is formed. The electrode terminal 9 and the lead pattern 11, and the lead pattern 11 and the circuit pattern 13 are connected to each other via an anisotropic conductive sheet or the like (not shown).

As described above, in the liquid crystal display element in which the non-display areas 10 having no transparent electrodes 1 and 3 are dispersed and arranged in the display area having the transparent electrodes 1 and 3, the transparent electrodes 1 and 3 are used. Transparent electrodes 1, 3 with and without
Since the cell gap G is different by the thickness of 1), there is a problem that color irregularities are easily scattered around the periphery of the display area. In order to improve such inconvenience, conventionally, as shown in FIG. 7, the non-display area 10 has a thickness equivalent to that of the transparent electrodes 1 and 3, and is electrically independent of the transparent electrodes 1 and 3 to transmit information. Electrodes not involved in display, that is, dummy electrodes 14 are provided to make the cell gap G uniform.

[0005]

However, in the prior art, since the dummy electrode 14 is formed in a shape so as to cover almost the entire non-display area 10, the electrostatic capacitance of that portion is large. In the case where the equalizing means as described in Japanese Patent Application Laid-Open No. 57-56044 is not applied between the transparent electrodes 1 and 3 and the dummy electrode 14, high voltage static electricity is generated during the rubbing process. The transparent electrodes 1 and 3 are likely to be electrically charged, and a discharge is generated between the transparent electrodes 1 and 3 and the dummy electrode 14, so that the transparent electrodes 1 and 3 are electrostatically damaged. Further, when the potential equalizing means is provided between the transparent electrodes 1 and 3 and the dummy electrode 14, it is possible to eliminate the inconvenience such as electrostatic breakdown of the transparent electrodes 1 and 3 during the rubbing process, but The process becomes complicated and the cost of the liquid crystal display element becomes high, and after the potential equalizing means is cut off, high voltage static electricity is likely to be charged to the large area dummy electrode 14 as well, so that the liquid crystal is caused by static electricity. Poor energizing bubbles, which is a phenomenon of destruction, are likely to occur.

The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid crystal display device which is inexpensive and is not easily affected by static electricity.

[0007]

According to the present invention, in order to achieve the above-mentioned object, non-display areas in which transparent electrodes are not formed are dispersed and arranged in a display area constituted by a transparent electrode group. In a liquid crystal display device in which a dummy electrode that is electrically independent of the transparent electrode is patterned in the non-display area, a plurality of dummy electrodes are separately formed for each non-display area.

[0008]

When a plurality of dummy electrodes are formed in one non-display area, the area per dummy electrode is reduced and the electrostatic capacity is reduced. In this case, defective electricity-carrying bubbles due to the charging of the dummy electrode in the above-mentioned item is less likely to occur, and the yield of good products and the durability of products are improved. Further, since it is not necessary to take special means for preventing electrostatic breakdown of the transparent electrode during the rubbing treatment, for example, the above-mentioned potential equalizing means, the cost can be reduced.

[0009]

1 is a plan view of a main part of a liquid crystal display device according to the first embodiment, and FIG. 2 is a cross-sectional view of the main part of the liquid crystal display device.
The same code | symbol is displayed on the part corresponding to FIG.

As shown in these figures, in the liquid crystal display element of this example, the upper transparent electrode 1 and the lower transparent electrode 3 are formed at the positions where the inner surfaces of the upper electrode substrate 2 and the lower electrode substrate 4 face each other. A large number of dot-shaped dummy electrodes 14 are formed for each non-display area 10. Other parts are formed similarly to the conventional liquid crystal display element shown in FIGS. The size of one dummy electrode 14 can be arbitrarily set in consideration of the electrostatic capacitance and the color unevenness, but as an example, it is equivalent to the size of one pixel in the display area (0.3 to It is particularly preferable to set it to about 0.4 mm square. The dummy electrodes 14 are printed and formed simultaneously with the transparent electrodes 1, 3 and the electrode terminals 8 by using a transparent conductive material such as ITO forming the transparent electrodes 1, 3 and the electrode terminals 8. These dummy electrodes 14 are formed electrically independent of each other and also electrically independent of the transparent electrodes 1 and 3 and the electrode terminal 8. Further, these dummy electrodes 14 are formed to have substantially the same thickness as the transparent electrodes 1 and 3 and the electrode terminals 8 in order to prevent color unevenness of the liquid crystal display element. In addition, the bonding method of the glass substrates 2 and 4,
The method of injecting the liquid crystal and the like are the same as the methods generally known from the past and are not the gist of the present invention, and thus the description thereof is omitted.

In the liquid crystal display element of the above-mentioned embodiment, since a large number of dot-shaped dummy electrodes 14 are formed in each non-display area, the area per dummy electrode is reduced and the capacitance of the dummy electrode is reduced. can do. Therefore, electrostatic breakdown of the transparent electrodes 1 and 3 during the rubbing process and defective conduction bubbles due to charging of the dummy electrode 14 during use are less likely to occur, and the yield of good products and the durability of products are improved. Further, since it is not necessary to take any special means for preventing the electrostatic destruction of the transparent electrodes 1 and 3 during the rubbing treatment, for example, the same electric potential applying means, the cost can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a plan view of an essential part of a liquid crystal display element according to the second embodiment, and the same reference numerals are displayed in the portions corresponding to those in FIG.

As shown in the figure, in the liquid crystal display element of this example, a plurality of linear dummy electrodes 14 are formed in each non-display area 10. Others are the same as those of the liquid crystal display element of the first embodiment shown in FIG. The liquid crystal display element of this example also has substantially the same effect as the liquid crystal display element of the first embodiment.

The gist of the present invention is that a plurality of dummy electrodes are formed separately for each non-display area, and the shape and arrangement of the dummy electrodes 14 are limited to the above-mentioned embodiment. It can be set arbitrarily without For example, in the above-described embodiment, the dummy electrodes 14 are formed on the inner surfaces of the upper electrode substrate 2 and the lower electrode substrate 4 at the positions facing each other, but as shown in FIG. The dummy electrode 14 can also be formed only on the inner surface of either one of them.

[0015]

As described above, according to the present invention,
Since a plurality of dummy electrodes are formed separately for each non-display area and the area per dummy electrode is reduced, the electrostatic capacity of the dummy electrode is reduced, and the transparent electrode is electrostatically destroyed during the rubbing process or during use. In this case, defective electricity-carrying bubbles due to the charging of the dummy electrode in the above-mentioned item is less likely to occur, and the yield of good products and the durability of products are improved. Further, since it is not necessary to take any special means for preventing electrostatic breakdown of the transparent electrode during the rubbing process, for example, the same potential applying means, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a liquid crystal display element according to a first example.

FIG. 2 is a cross-sectional view of a main part of the liquid crystal display element according to the first embodiment.

FIG. 3 is a plan view of an essential part of a liquid crystal display element according to a second embodiment.

FIG. 4 is a cross-sectional view of essential parts of a liquid crystal display element according to another embodiment.

FIG. 5 is a cross-sectional view of a main part of a liquid crystal display element.

FIG. 6 is a plan view of an essential part of a liquid crystal display device having no dummy electrode.

FIG. 7 is a plan view of a main part of a liquid crystal display device according to a conventional example.

[Explanation of symbols]

1 Upper transparent electrode 2 Upper electrode substrate 3 Lower transparent electrode 4 Lower electrode substrate 10 Non-display area 14 Dummy electrode

Claims (2)

[Claims] 1. A non-display area in which a transparent electrode is not formed is dispersedly arranged in a display area including a transparent electrode group, and a dummy electrode electrically independent of the transparent electrode is provided in the non-display area. 2. A liquid crystal display element in which a plurality of dummy electrodes are divided and formed for each non-display area in the liquid crystal display element in which the pattern is formed. 2. The liquid crystal display element according to claim 1, wherein the size of the dummy electrode is substantially equal to the size of one pixel in the display region.