JPH01182828A - Liquid crystal display panel - Google Patents

Abstract

PURPOSE:To easily realize gradation display by forming an intermediate foundation film different in material from one electrode at least on a part of this electrode and forming the foundation surface of one orienting film in one picture element, which is determined by this electrode, with plural different foundation faces and controlling the voltage applied between this electrode and the other electrode. CONSTITUTION:An intermediate foundation film 21 whose material is different from one electrode 12 is formed at least on a part of this electrode 12, and the foundation surface of one orienting film 13 in one picture element 18 determined by electrodes 12 and 15 is formed with plural different foundation faces. Since a part of the foundation surface of at least one orienting film 13 in one picture element is formed with the film face 21 consisting of a material other than an ITO film though the foundation surface of the orienting film 13 in a display panel is normally the surface of a transparent electrode consisting of an ITO, the polarity energy on the surface of the orienting film 13 on the foundation surface whose state is partially different is partially changed and plural areas different in threshold voltage can be provided in one picture element. Thus, the voltage-transmitted light quantity characteristic is very gentle as the whole of picture elements in comparison with a conventional panel and variable contrast display is possible.

Description

[Detailed Description of the Invention] [Summary] Regarding the structure of a liquid crystal display panel, especially a ferroelectric liquid crystal display panel that enables multi-gradation display, - By providing regions with different threshold voltages within a pixel, ferroelectric In order to realize the slow voltage-transmitted light amount characteristic of the ferroelectric liquid crystal and to enable good multi-gradation display, we placed a pair of substrates facing each other on both sides of the ferroelectric liquid crystal layer. In a display panel in which an electrode and an alignment film are laminated on each surface, an intermediate base film different from the electrode is formed on at least a part of the one electrode, and one of the layers within one pixel defined by the electrode is formed. The underlying surface of the alignment film is composed of a plurality of different underlying surfaces, and the configuration is such that gradation display can be performed by controlling the voltage applied between the electrode and the other electrode.

[Industrial application field]

The present invention relates to a liquid crystal display panel, and more particularly to the structure of a ferroelectric liquid crystal display panel capable of displaying multiple gradations.

Liquid crystal display panels using ferroelectric liquid crystals have better image quality and response speed of 100% compared to conventional TN type liquid crystal display panels.
It is more than twice as fast and has great features such as memory function, and has recently become popular.

Taking advantage of these advantages, applications and practical applications for displays are progressing.

In such a ferroelectric liquid crystal display panel, ON and OP
Naturally, multi-gradation display is required in addition to black-and-white display using p, but since the voltage-transmitted light amount characteristic of ferroelectric liquid crystals is steep, the range of gradation display by voltage control is extremely small, making it difficult. There is.

For this reason, there is a strong demand for a panel configuration using ferroelectric liquid crystal that can easily realize gradation display through voltage control.

[Conventional technology]

As shown in Figure 3, the conventional ferroelectric liquid crystal display panel
A transparent rear glass substrate If, on which a striped first transparent electrode 12 made of, for example, ITO (Indiuw+Tin Oxide) is formed, is also made of ITO.
A ferroelectric liquid crystal layer 1 is interposed between a transparent front side glass substrate 14 on which a stripe-shaped second transparent electrode 15 is formed, via a first alignment film 13 and a second alignment film 16, respectively.
7 is enclosed, and the surface of at least one of the first alignment film 13 and the second alignment film 16, for example, the first alignment film 13, is subjected to an alignment treatment such as rubbing,
The entire liquid crystal molecules are aligned uniformly in a certain direction.

[Problem that the invention seeks to solve]

By the way, in the conventional liquid crystal display panel as mentioned above,
Since the voltage-transmitted light amount characteristic of the ferroelectric liquid crystal 17 is steep, the display is only black and white depending on ON and OFF, and it is possible to realize a gradation display corresponding to gray or the like in between by controlling the ON voltage. It was extremely difficult.

In other words, the difficulty in displaying gradations is that the applied voltage is 0N.
-The reversal between the two stable states of black and white display on the liquid crystal when turned OFF is completed in a very short time, so-called response speed is extremely fast.
Moreover, this is due to the fact that the dark value voltage produced by this inversion is uniform.

In view of the above-mentioned drawbacks of the conventional technology, the present invention provides a novel high-strength method that realizes a slow voltage-transmitted light amount characteristic by providing regions with different dark value voltages within one pixel, thereby enabling good multi-gradation display. The object is to provide a dielectric liquid crystal display panel.

[Means for solving problems]

In order to achieve the above object, the present invention provides a display panel in which a pair of substrates are arranged facing each other on both sides of a ferroelectric liquid crystal layer, and electrodes and alignment films are laminated on the opposing surfaces of each substrate. forming an intermediate base film different from the electrode on a part of the one electrode, and configuring the base surface of the first alignment film within one pixel defined by the electrode with a plurality of different base surfaces; Gradation display can be performed by controlling the voltage applied between the electrode and the other electrode.

[For production]

The electro-optical properties of ferroelectric liquid crystals differ from those of TN-type liquid crystals, etc., and depend on the material, thickness, and surface condition of the alignment film, for example, which is in direct contact with the liquid crystal. It sensitively reacts and changes not only due to the rubbing treatment method, etc., but also due to differences in the surface condition of the underlying layer of the alignment film.

Therefore, the underlying surface of the alignment film in the display spring 7Lz is normally the surface of a transparent electrode made of ITO, but a portion of the underlying surface of at least one of the alignment films within one pixel is made of ITO.
By using a film surface made of a material other than the film, the polarity energy on the surface of the alignment film on the underlying surface with partially different surface □ states changes partially, and a plurality of layers with different dark value voltages are generated within one pixel. A region can be provided. As a result, the voltage-transmitted light amount characteristic (electro-optical characteristic) of the entire pixel becomes much slower than that of a conventional panel, making it possible to display multiple gradations.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part showing an example of one pixel portion in a liquid crystal display panel using ferroelectric liquid crystal according to the present invention, and the same parts as in FIG. 3 are given the same reference numerals. .

The embodiment shown in this figure differs from the example shown in FIG. 3 in that an intermediate base film 21 made of a material different from that of the electrode is provided on a part of the surface of the first transparent electrode 12.

That is, for example, a 1,000-layer film made of ITO or the like is coated with a first alignment film 13 of 1,000-layer thickness made of polyimide or the like.
A transparent back-side glass substrate 11 on which a striped first transparent electrode 21 with a thickness of 2 μm is formed, a ferroelectric liquid crystal layer 17 with a thickness of 2 μm, and a ferroelectric liquid crystal layer 17 with a thickness of 1000 μm made of polyimide or the like. 2 made of ITo etc. covered with a bi-oriented film 16
The transparent front side glass substrate 14 on which the striped second transparent electrode 15 with a film thickness of 0.000 mm is formed is arranged opposite to the striped first and second transparent electrodes 21.15 so as to intersect with each other. ing.

Up to this point, there is no difference from the conventional method, but in the present invention, within one pixel 18 of, for example, 300 x 300 μm, which is determined by the intersections of these electrodes, a 200-layer film made of, for example, 5iO1 is applied to a half area on one side of the first transparent electrode 21. An intermediate base film 21 having a film thickness of . The electrode 21 provided with the intermediate base film 21 has a partially different surface state, and therefore the base surface of the first alignment film 13 also partially differs. Thereafter, the first alignment film 13 made of the polyimide is coated on the underlying surface.

In addition to SiO□, Alt's or polyvinyl alcohol (P
A transparent material film such as VA) can be used.

Further, as a method for providing the intermediate base film 21 made of 5iOz or the like in a half region on one side of at least one first transparent electrode 21 within one pixel 18 described above, the first transparent electrode 21 is formed by patterning. After that, it can be easily formed by making full use of, for example, a sputtering method and a photolithography process.

Incidentally, in a ferroelectric liquid crystal display panel having such a configuration, a pulse width of 500
The change in the amount of transmitted light when applying a pulse voltage of μs is the second
As shown in the figure.

After applying the pulse voltage to the display panel to bring it into a display state, in order to stably maintain this display state, an AC voltage with a frequency of 2 kHz and a voltage of 5 cm is applied (AC stabilization method). As a result of examining the electro-optical characteristics of the display panel, as shown in the figure, the transmitted light amount characteristic (I) with respect to the applied voltage of the display panel of the present invention is extremely superior to the characteristic (II) of the conventional ferroelectric liquid crystal display panel. It turned out to be slow.

Therefore, by controlling the applied voltage, the degree of intermediate tone (gray) to be displayed can be easily selected.
Multi-gradation display becomes possible.

〔Effect of the invention〕

As is clear from the above description, according to the liquid crystal display panel using ferroelectric liquid crystal according to the present invention, - a part of the base surface of at least one alignment film in the pixel is formed of a film made of a material other than an ITO film; By making it a surface, the polar energy on the surface of the alignment film provided on the underlying surface having partially different surface conditions changes partially, and a plurality of regions with different dark value voltages are formed within the pixel. , extremely slow voltage-transmitted light amount characteristics (electro-optical characteristics) can be obtained, and multi-gradation display can be easily realized by voltage control.

Therefore, there are practical effects such as improved display quality.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part showing one pixel portion of an embodiment of a liquid crystal display panel according to the present invention, FIG. 2 is a diagram showing electro-optical characteristics of a liquid crystal display panel according to the present invention, and FIG. 3 is a conventional FIG. 2 is a cross-sectional view of main parts for explaining the ferroelectric liquid crystal display panel of FIG. In FIG. 1, 11 and 14 are glass substrates, 12 is a first transparent electrode, 13 is a first alignment film, 15 is a second transparent electrode, 16 is a second alignment film,
17 is a ferroelectric liquid crystal layer, 18 is one pixel, and 21 is an intermediate base film.
+i*f Je Midori 1.1 Furnace Hishi 5iars Figure 1 → Soku 7701 Zurusu 斤甤电收田Characteristics Chart Yura Table - 3πノ1 Table j Mi C Nell Ne'ffe & Surface 1 Revised Figure 3

Claims (1)

[Claims] A pair of substrates (11, 1
4) are arranged facing each other, and electrodes (12, 15) and alignment films (13, 16) are placed on the opposing surfaces of each substrate (11, 14), respectively.
In a display panel in which the electrode (12) is laminated, at least a portion of the one electrode (12) is
12) is formed, and the underlying surface of one alignment film (13) within one pixel (18) determined by the electrodes (12, 15) is formed on a plurality of different underlying surfaces. 1. A liquid crystal display panel comprising: a liquid crystal display panel characterized in that gradation display can be performed by controlling the voltage applied between the electrode (12) and the other electrode (15).