JPS6149675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display device having a matrix electrode structure composed of a row electrode group and a column electrode group that intersect with each other, and in particular to a technique for improving display parallax in a multilayer liquid crystal display device. This is what we advocate.

Matrix-type liquid crystal display devices are being developed to have higher density and multi-line displays, with the aim of improving image quality by taking advantage of their low power consumption.

As a driving method for a matrix type liquid crystal display device, for example, a line sequential scanning method as shown in FIG. 1 is used. Regarding this line-sequential scanning method, the first
This will be explained with figures. The main memory device 1 stores characters, symbols, graphic patterns, etc., and this stored data is converted into a display pattern by a character signal converter 2 and stored in the buffer memory in the column drive circuit 3 for each row of the display screen. After that, connect the output to the column electrode
Supplied to Y ₁ , Y ₂ , ...Y _o respectively. On the other hand, the row electrodes X ₁ , X ₂ , _...
The information stored in the buffer memory is displayed line by line. In the figure, numeral 5 is a control device for controlling the operations of the column drive circuit and row drive circuit, and 6 is a liquid crystal display device having matrix type electrodes.

In this matrix type liquid crystal display device, the greater the number of lines (number of scanning lines), the higher the display density and the better the image quality. becomes smaller and therefore crosstalk (crosshair effect)
Problems such as this will occur. In particular, in a liquid crystal display device using liquid crystal as a display device, sufficient contrast cannot be obtained because the threshold value as a characteristic of the liquid crystal is not steep and the response (response characteristic) is slow. In order to solve these problems, the following various measures have been proposed.

Involvement of liquid crystal materials with more distinct threshold characteristics.

By further optimizing the matrix addressing method, the drive margin (α=Von/
Voff).

Improving the electrode structure and cell structure to increase apparent resolution.

Among these methods, method and method do not require major changes to the structure of conventionally known liquid crystal cells, but considering the current development status of liquid crystal materials, it is possible to dramatically increase the number of lines that can be driven. cannot be expected. Although this method complicates the structure of the liquid crystal cell, it is possible to reliably increase the number of lines that can be driven by two, three, four times, and so on. As specific examples of the above methods, three methods have been proposed: (a) dual electrode structure method, (b) upper and lower division method, and (c) two-layer structure method. It is also possible to mutually combine these three methods. Regarding this, an application has already been filed in Japanese Patent Application No. 81794/1983.

However, when the above method (c) is adopted, by making the liquid crystal cell structure a multilayer structure with two or more layers, display parallax due to the step difference in the display section inevitably becomes a problem, and this display parallax deteriorates the display quality. This results in a significant decrease. That is, when displaying characters such as letters, figures, and moving images, when viewing the liquid crystal device from the front, each row electrode and column electrode is Each is correctly recognized according to its arrangement form. However, when viewing this liquid crystal device from a slightly diagonal downward direction, for example, the display pixels overlap, making it difficult to discern the pattern due to the difference in level between the front liquid crystal cell and the rear liquid crystal cell.

The liquid crystal display device shown in FIG. 2 is a sectional view of a conventional multilayer matrix type liquid crystal display device. TN-FEM type liquid crystal cells 11 and 12
In the front (observer side) liquid crystal cell 11, column electrodes 14a, 1 are arranged on the front glass 13.
4b, . . . are provided, and row electrodes 16a, 16b, . . . are provided on the front side of the central glass 15. The rear liquid crystal cell 12 has column electrodes 17a on the back side of the central glass 15.
17b,... are provided, and a row electrode 19 is provided on the rear glass 18.
a, 19b, ... are provided. At this time, liquid crystal cell 1
Row electrodes 16 and 19 of Nos. 1 and 12 are arranged so as not to overlap each other, but column electrodes 14 and 17 are arranged so as not to overlap each other.
are arranged so that they overlap.

Through the above steps, a multilayer matrix type liquid crystal display device is manufactured. FIG. 3 is an explanatory diagram showing the display state of this liquid crystal display device. In FIG. 3, the row electrodes 19a, 19b, . . . show their apparent positions when viewed obliquely from below, and hatched portions indicate dots to which an electric field is applied.

This phenomenon in which the display becomes difficult to see occurs particularly when viewed from diagonally above or diagonally below because the row electrodes are arranged between the front and rear cells.

Although the problem of parallax mentioned above can be improved to some extent by making the central glass 15 thinner, it cannot be made extremely thin because the mechanical strength of the central glass is required for leading out the terminals.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a multilayer liquid crystal display device having an electrode pattern that reduces the adverse effects of parallax on a display screen by making full use of technical means.

Hereinafter, the present invention will be explained in detail according to embodiments with reference to the drawings.

FIG. 4 is a cross-sectional view of a liquid crystal display device having a two-layer liquid crystal cell structure showing one embodiment of the present invention.

The front glass 13 and the center glass 15 constitute the front liquid crystal cell 11, and column electrodes 14a, 14b, . . . are provided on the front side of the center glass 15. Row electrodes 16 are arranged on the inner surface of the front glass 13, and when one digit is displayed in a 5 column x 7 row matrix, at least 7 rows of row electrodes 16a to 1 are arranged.
6g as one group, and this group is provided on the inner surface of the front glass 13. Next, the center glass 15 and the rear glass 18 constitute the rear liquid crystal cell 12, and the column electrodes 17a, 17b, . . . are arranged on the inner surface of the rear glass 18. These column electrodes 17a, 17b... are arranged so as to overlap with the column electrodes 14a, 14b... on the front side.
The rear liquid crystal cell 12 is provided with row electrodes 19, and the number of rows corresponding to one digit, for example, seven rows and one
9h to 19n are formed into a group, and this group is provided on the back side of the central glass 15.

That is, in a liquid crystal cell having a two-layer structure as in this embodiment, the row electrodes 16 and 19 are arranged as one group of row electrodes 16a to 16g aligned on the front glass 13 and one group of row electrodes 16a to 16g aligned on the central glass 15. Row electrodes 19h to 19n
It consists of two groups. Therefore row electrode 16,1
9 has only one step. If this stepped portion is installed at the boundary between display areas, the stepped portion will not appear in the display pattern within the display area.
To set the display area, move the display pattern to an appropriate position,
For example, the pattern is divided into groups at boundaries that can be divided without cutting, and step portions of the row electrodes 16 and 19 are provided corresponding to these boundaries, and the two divided sections are each used as a display area.

In the above embodiment, the upper part of the row electrode is the front liquid crystal cell 11, and the lower part of the row electrode is the rear liquid crystal cell 12.
By forming the display pattern, a step difference in the display is generated only in the central portion where the display pattern is not cut. The display state at this time is shown in FIG. As is clear from FIG. 5, if the display pattern does not overlap the level difference in the center, the display pattern can be discerned without being affected by parallax even when viewed diagonally from above and below. Similar effects can be obtained even if the row electrodes of the above embodiment are arranged such that the upper part is arranged in the rear liquid crystal cell 12 and the lower part is arranged in the front liquid crystal cell 11. It is also possible to provide a display device in which the row electrodes and column electrodes are replaced with each other, if necessary. When the liquid crystal cell has an n-layer structure of three or more layers, only (n-1) step portions are exposed.

6 and 7 are perspective views of a multilayer liquid crystal cell structure display device showing other embodiments of the present invention, respectively.

Figure 6 shows two electrodes with a dual matrix electrode structure.
FIG. 7 also shows a three-layer cell with a double matrix electrode structure.

In the embodiment shown in FIG.
19g are arranged in one group at the upper part of the rear cell side of the central glass 15, and one row electrode 19a to 19g each.
Column electrodes 1 arranged on the rear glass 18 for the book
7 correspond to each other and form a matrix. Therefore, one matrix contains two picture elements. In addition, the front cell has a row electrode 16.
a to 16g are arranged as one group at the lower part of the front cell side of the central glass 15. Column electrodes 14 are arranged on the front glass 13 so as to form a double matrix corresponding to the row electrodes 16a to 16g.

FIG. 7 shows a case where the liquid crystal cell shown in FIG. 6 is made up of three layers, and the row electrodes are sequentially arranged in groups from the rear cell side at the top, center, and bottom. In this case, two steps appear at the boundary between the row electrode groups.

As described in detail above, according to the present invention, in a multilayer display device, the electrodes are arranged in groups on the same substrate surface, and the number of groups is made the same as the number of layers of the cell, thereby reducing the level difference (layer). Since it can be reduced to (1), the adverse effects of parallax can be significantly alleviated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a circuit configuration for driving a matrix type liquid crystal display device. Second
The figure is a cross-sectional view showing a conventional multilayer liquid crystal display device. FIG. 3 is an explanatory diagram showing the display state of the multilayer liquid crystal display device shown in FIG. 2. Figure 4 shows part 1 of the present invention.
1 is a cross-sectional view of a two-layer liquid crystal cell structure display device showing an example. FIG. 5 is an explanatory diagram showing the display state of the liquid crystal display device shown in FIG. 4. 6 and 7 are perspective views of a multilayer liquid crystal display device showing other embodiments of the present invention, respectively. 11...Front cell, 12...Back cell, 13...
...Front glass, 14, 17... Column electrode, 15...
Central glass, 16, 19... row electrodes, 18... rear glass.

Claims (1)

[Claims] 1 N layers of display cells containing display media (N is 2
In a multilayer cell structure display device in which a display pattern is formed by arranging a matrix electrode structure consisting of a row electrode group and a column electrode group in a superimposed multilayer cell structure, the row (column) electrode group is queue)
It is composed of a collection of small electrode groups divided into N pieces by boundaries parallel to the direction, and one electrode group for each display cell.
The boundaries are set so that the steps corresponding to the display cells occurring at the boundaries are arranged at positions that do not cut the display pattern, and the boundaries are superimposed for each display cell. A multilayer cell structure display device characterized in that column (row) electrode groups of the matrix electrode structure are arranged in N layers.