JPH03189622A - Ferroelectric liquid crystal element - Google Patents

Abstract

PURPOSE:To allow gradation display without increasing control parts by connecting plural pieces of electrodes via electric parts having the electric resistances different from each other to a common electrode driving circuit. CONSTITUTION:A scanning electrode consists of two pieces of the electrodes S1A, S1B having the same width in the Sa part where a picture element is formed at the intersected part of the electrodes. An Sb part to regulate the electric resistance is provided in this Sa part and the Sc part where the S1A and S1B are connected. The electrodes S1A and S1B are formed to the different widths. The voltage drops of different values are generated in this part so that the different voltages are applied with the S1A and S1B in the Sa part. Signal electrodes are made of the same constitution as the constitution of the scanning electrodes. The electrodes on upper and lower substrates 1, 2 are formed as a matrix. These electrode groups are connected to the common electrode driving circuit via the electric parts having the resistances different from each other. The gradation display is then possible without increasing the electronic parts for controlling writing signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ferroelectric liquid crystal element, and more particularly to a cell structure of a ferroelectric liquid crystal cell that enables gradation display.

[Conventional technology]

Because ferroelectric liquid crystals have memory properties and high-speed response on the microsecond scale, they are expected to be put to practical use in large-capacity displays and high-speed liquid crystal shutters.

Conventionally, when controlling the transmission of light using this ferroelectric liquid crystal, binary control was generally used to either transmit the light or not transmit the light. This is because ferroelectric liquid crystal has two stable alignment states, one that transmits light and one that does not transmit light, but the transition process operates at high speed, so this can be used to control the amount of light transmission to an intermediate state. This is due to the difficulty of

Therefore, in order to control the intermediate stage, for example, in Japanese Patent Application Laid-Open No. 63-37318, gradation display is performed by controlling the area of the portion of each pixel through which light passes. In Japanese Patent No. 2023, the amount of light transmitted is controlled by applying a voltage gradient within the pixel. Furthermore, as shown in FIG. 4, the scanning electrodes constituting one pixel are made into two such as SIA, SIB or S2A, 82B,
The signal electrodes are also two each like DIA, DIB or D2A, D2B, for example SIA%SIB and DIA,
The pixel G11 made up of DIB is made up of four small pixels, and the drive circuit provided for each electrode
There is an example of controlling the lighting of one small pixel to display gradation of that one pixel.

[Problem to be solved by the invention]

Although such conventional methods can display gradation using ferroelectric liquid crystal, the cell structure becomes complicated and the number of electrodes to configure one pixel increases, so the number of electrodes must be adjusted accordingly. This has drawbacks such as an increase in the number of drive circuits.

An object of the present invention is to solve these problems and provide a ferroelectric liquid crystal element that has a simple cell structure and can display gradations without increasing the number of electronic components for controlling write signals. shall be.

[Means to solve the problem]

In order to achieve the above object, the present invention sandwiches a ferroelectric liquid crystal between two substrates each having a scanning electrode and a signal electrode on opposing surfaces, and a pixel is formed at the intersection of the scanning electrode and the signal electrode. is divided into a plurality of small pixels by using at least one of the scanning electrode and the signal electrode as a plurality of electrodes, and an electrode drive circuit connected to these electrodes lights up each small pixel.
In a ferroelectric liquid crystal device that controls lighting and displays gradation, multiple electrodes corresponding to one pixel are connected to a common electrode drive circuit through electrode portions that have different electrical resistances. , is characterized in that multiple electrodes can be controlled by a common drive signal.

[Effect]

In the present invention, as in the conventional example shown in FIG. 4, one pixel is divided into small pixels, and light transmission and
Although opacity is controlled, the structure of the electrodes forming the small pixels of each pixel is different from that of the conventional example.

In order to make one pixel consist of mXn small pixels, if m upper or lower substrate electrodes and n lower or upper substrate electrodes are provided corresponding to one pixel, their intersection m One pixel is formed by forming n small pixels. Here, in the conventional example, a drive circuit is provided for each of m and n electrodes to drive them. However, in the present invention, the m electrodes are connected to a common electrode drive circuit through electrode portions each having a different electrical resistance, and the n electrodes are also configured in the same manner.

With such an electrode configuration, when each electrode forming a small pixel is driven from a drive circuit common to one pixel, the voltage drop in the middle of each electrode is different, resulting in a different voltage at each small pixel portion. Therefore, transmission or non-transmission of light can be controlled for each small pixel. In other words, each small pixel can be controlled by a common drive circuit for one pixel, without having to provide a drive circuit for each electrode corresponding to each small pixel as in the conventional example.

〔Example〕

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

FIG. 1 is a configuration diagram of a transparent electrode on a substrate of a liquid crystal cell of the present invention.

In FIG. 1, 1 is an upper substrate, 2 is a lower substrate, SL to SN are scanning electrodes formed on the side of the upper substrate facing the lower substrate, and Dl to DN are scanning electrodes formed on the lower substrate facing the upper substrate. This is a signal electrode formed on the side.

A pixel is then formed at the intersection of each electrode.

For example, as shown in Sl, the scanning electrodes are two electrodes SIA and SI of the same width in the Sc part where pixels are formed.
An sb part for adjusting electrode resistance is provided between this Sc part and the Sc part where SIA and SIB are connected, and the widths of the electrodes of SIA and SIB are made different.
Different values of voltage drops are generated in this portion, and different voltages are applied to SIA and SIB in the Sc portion.

Similar to the scanning electrode, the signal electrode is made up of two electrodes, DIA and DIB, as shown by Dl.The Da part has the same width, the Db part has different widths, and they are connected in the Dc part. There is.

In this example, the width of the electrode in the Sa part and the Da part is 25
0μm, Sb part and Db part are both 250μm wide.
m, the narrower one was 5 μm.

An organic alignment film was coated on the transparent electrodes formed in such a shape, and after a rubbing treatment was performed, the electrodes on the respective substrates were stacked so as to form an IJ pattern. Pixels are formed at intersections between the electrodes of the upper and lower substrates. for example,
A pixel G11 is formed at the intersection of the scanning electrode S1 and the signal electrode Dl. Here, G11 is composed of four small pixels G11a, 0
11b.

Consists of G11c and G11d.

FIG. 2 is a cross-sectional view of the first liquid crystal cell taken along the line AA'. SIA, SIB, D on the opposing surfaces of the upper substrate 1 and lower substrate 2.
There is a transparent electrode indicated by IA or the like, and an alignment film 3 is provided thereon. The side substrates are stacked on top of each other with a spacer 6 in between, and a ferroelectric liquid crystal 5 is sealed in a cell surrounded by a seal 4.

FIG. 3 shows the voltage waveform applied to the electrodes of a liquid crystal cell having such a structure and the lighting state of small pixels within one pixel at that time.

The upper row shows the voltage waveform applied to the scanning electrode, and the left column shows the voltage waveform applied to the signal electrode. The voltage waveform at the intersection is the voltage waveform applied to each small pixel.

Here, V o V + V 2 has a different value for each small pixel, and the magnitude is shown on the right of each waveform based on the threshold voltage vth for lighting and non-lighting.

In FIG. 3, (a) applies a positive and negative pulse with a peak value Vs to the scanning electrode and a positive and negative pulse with a peak value VR to the signal electrode, thereby turning all the small pixels from G11a to G11d into a non-lighting state. It shows that.

(b) shows the peak value of VDI when a voltage with a phase 180° different from that at the time of reset is applied to the signal electrode, and only the small pixel G11a constituted by the electrodes with low electrode resistance in the Sb and Db portions in Fig. 1 is shown. , a write voltage VI exceeding the threshold voltage vth is applied and the light is turned on.

Other small pixels remain in the non-lighted state. Furthermore, when a pulse of VD2, which is higher than VDI, is applied to the signal electrode, either the sb portion or the Db portion in FIG. , new 011b and G11
c lights up.

In this way, even if multiple electrodes that make up one pixel are driven with a common signal, a different voltage is applied to each subpixel due to voltage drop in the middle of the electrode, making it difficult to control whether each subpixel turns on or off. This makes it possible to display gradations based on area.

In this example, only the voltage level of the signal electrode was changed,
Although we have controlled the lighting of small pixels, by changing the voltages of both the scanning electrode and the signal electrode, it is possible to support even more divisions with a smaller number of voltage levels.

〔Effect of the invention〕

As described above, according to the present invention, in order to display gradation,
Because the electrode configuration allows multiple electrodes that divide one pixel into multiple small pixels to be driven by a common electrode drive circuit, stable gradation display with excellent display quality can be achieved without increasing the number of drive circuits. It becomes possible to provide a ferroelectric liquid crystal element.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing the electrodes of the liquid crystal element of the present invention, Fig. 2 is a cross-sectional view of the liquid crystal panel of Fig. 1, and Fig. 3 is a drive signal for driving the liquid crystal element of Fig. 1 and the lighting state of the pixels. FIG. 4 is a configuration diagram showing electrodes of a conventional liquid crystal element. 1... Upper substrate, 2... Lower substrate, 3... Alignment film, 4... Seal. 5...Liquid crystal, 6...Spacer, 81~SN...Scanning electrode, D1~DN...Signal electrode, G11...Pixel , G11 a=G11 d---small pixel, Sa,
Da: pixel electrode section, Sb, Db: electrode resistance adjustment section, Sc, Dc.
・・・・・・Electrode connection part. Figure 3 Figure 4 L)IA L)11=5 LIZAllfl

Claims (1)

[Claims] A pixel formed at the intersection of a scanning electrode and a signal electrode is divided into a plurality of small pixels by making at least one of each scanning electrode and each signal electrode a plurality of electrodes, and an electrode drive circuit connected to the electrode. In a ferroelectric liquid crystal element that controls lighting and non-lighting for each small pixel to display gradation, the plurality of electrodes are driven by a common electrode through electrode portions having different electrical resistances. A ferroelectric liquid crystal element characterized by being connected to a circuit.