JPS60113293A - Driving of liquid crystal panel - 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 (4) Technical Field of the Invention The present invention relates to a method for driving a liquid crystal panel, and particularly relates to a liquid crystal panel that is integrated into an integrated circuit and is capable of driving a high-voltage liquid crystal panel using a saw drive circuit. Regarding the method of driving the panel.

(0) Technology background Among the liquid crystal panels, there is a storage type liquid crystal panel.

This type of liquid crystal panel requires a driving voltage as high as 20 to 30 volts compared to other types of liquid crystal panels.

There are problems with the driving method that applies such a high driving voltage to the liquid crystal panel, and there are various technical issues that must be solved.
In particular, there is a problem with storage type liquid crystal panels that prevents the use of integrated drive circuits.

(c) Conventional technology and problems The conventional driving method for storage type liquid crystal panels (liquid crystal panels with memory function) uses, for example, 3x3 liquid crystal cells as shown in (1-■) in Figure 1. I want to drive as shown, i.e.
When driving ・ as a display cell (selected cell blocks light) and ○ as a non-display cell (non-selected cell passes light), the voltage waveforms applied to these cells are (1- 2
), it was a method of controlling the voltage to three levels (+V, 0.-Vl).Currently known integrated drive circuits that use this drive method include: , its breakdown voltage is only about ±15 volts.Therefore, storage-type LCD panels that require high driving voltages such as those mentioned above, such as those that need to be driven at a voltage of I5 volts or more, or those that have a sufficient contrast If you want to obtain a high drive voltage as described above, the conventional driving method described above is insufficient.Also, if you try to obtain a high drive voltage as described above using this conventional driving method, the drive circuit becomes large and the size of the display device increases. It gets bigger and costs more.

(-) Purpose of the Invention The present invention was devised in view of the drawbacks of the conventional driving method as described above, and its purpose is to provide a wide range of high-voltage drop type liquid crystal panels using an existing and simple circuit configuration. An object of the present invention is to provide a method for driving a liquid crystal panel that can drive a liquid crystal panel with a high display quality while maintaining a drive margin.

(1;) Structure of the Invention In order to achieve this objective, the driving method of the present invention sets a reference potential of a group of driving circuits connected to one electrode of a liquid crystal cell formed in a matrix to a predetermined value when driving a liquid crystal panel. A predetermined voltage of the same polarity as the reference potential is superimposed on the reference potential during any period in which the reference potential is changed at a period of A predetermined voltage is applied from the drive circuit group connected to the other electrode to the corresponding one electrode in accordance with the timing of one of the two levels of the reference potential to select or non-select that electrode. This is how it was done.

(F) Embodiments of the Invention The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 is a circuit diagram implementing the method of the invention.

In this figure, CI1 to C33 are liquid crystal cells of an accumulation type liquid crystal panel. Scanning signal supply lines Y1.corresponding to the counter electrodes of these liquid crystal cells. Y2. Y3, and data pulse supply line X1. X2. X3 is connected. Scanning signal supply lines Yl, Y2 . Y3 is a corresponding IC driver, for example, IC driver Q for scanning signal supply line Y1.
Y I 1 +QY,2 via the reference voltage (this is a voltage that switches between a high level (e.g. ■ volts) and a low level (e.g. earth potential) at a predetermined period), the reference voltage (e.g. It is configured so that a predetermined voltage (represented by ■) of positive polarity is applied. Also, data signal supply lines XI, X2;
C driver, for example, I for data signal supply line XI
A corresponding predetermined voltage, for example 2V or ground potential, is applied via the C driver Qx11°Qy+p.

In this way, by configuring the drive circuit for the storage type liquid crystal panel, during initialization, that is, clearing of the liquid crystal cell, each scanning signal supply line is used in the first half of each cycle.
, and the ground potential is supplied to each data signal supply line.
QXI I; QY22・QX2+; Qyz2. Q
X31 is turned on and IC driver Qy+ 1+
Qx+ 2 ; Qyz + + QX2 a ; Qy3
+ + QX32 is turned off, or in the latter half, I
C driver QY.

+, Qχl 2 1QY2+ + QX22 ;Qy3
11QX32 is turned on, IC driver QY+a
+ Qx+ l 1QY22. Qx2+;Qy32°QX3+ is turned off (see Figure 2).

An example of writing performed following this initialization is:
It is as follows. That is, during the period in which the scanning signal supply line Y1 is selected, the data signal supply line X1. X2. Assume that X3 is selected. In that case, Qy+ 2 , QX3 a are turned on during the first half of the period, and Qy+ +
, QX3 + is turned off and QX+ + + QX2
+ is turned on and Qx+ 2 and QX22 are turned off. Then, during the second half of the cycle, Qy+ , +
QX3. is turned on and QY,2°Qx3□ is turned on, causing QX,2, Qx22 to be turned on and Qx,1 +
QX21 is turned off. As a result, writing to the liquid crystal cell c, I + c, 2 is not performed and the liquid crystal cell is placed in a non-display state (light is transparent, indicated by O in (3-1) of FIG. 3), and writing to the liquid crystal cell CI3 is not performed. Writing is performed and the display state (by blocking light, indicated by . in (3-1) of FIG. 3) is made. During this period, Qy2+ + QY3+ are turned on and QY22 is turned on in the first half so that the voltage of V is supplied to the unselected scanning signal supply lines Y2 and Y3.
, Qyz 2 are turned off, and in the latter half, Qy22+ and QY32 are turned on and QYz+ and QY3+ are turned off. As a result, C2, ~C23,
Writing to C31 to C33 is not performed.

In this fixing after writing, the manner in which signals are supplied to the data signal supply line is exactly the same as in the initialization, whereas the signal supplied to the scanning signal supply line is set to {circle around (2)}. Therefore, in the first half of each cycle, Qy+ + + QY
2 + + QY3 + on and QYla, Qv
2a +'Qyi 2 is turned off, QY3□ is turned on, and QY+I + QY2, +Qy3+ are turned off.

During the accumulation period, both the scanning signal supply line and the data signal supply line are maintained at 0V/L/).

The circuit itself used for the drive as described above is easily available, and the present invention has found a means to utilize such a compact drive circuit integrated as a circuit. This makes it possible to drive storage-type liquid crystal panels, which require extremely high drive voltages, with a wide drive margin while also improving display quality such as contrast. The drive circuit configured based on the above means selects and non-selects the line in two ways.
It can be controlled at a variable level, and the power supply can be unipolar. The drive circuit for the slave can be easily constructed. In particular, when driving a multi-line liquid crystal panel, if an IC driver with multi-line output is used, it becomes easy to provide a small and lightweight liquid crystal display device with a wide driving margin.

Note that the number of pulses in each step and the period in which one line is driven are arbitrary. Also, the liquid crystal cell is driven by binary control of approximately 0 volts and 2 volts on the data side and approximately 0 volts and V volts on the scanning side, but (-
Combinations such as 2V, O), (-2V, -V), etc. may also be used.

(+) Effects of the Invention L: As stated above, according to the present invention, it is possible to (1) provide a means for using an existing integrated circuit drive circuit to drive a high-voltage liquid crystal panel; The panel can be driven with a wide driving margin while promoting improvement of display quality such as Shigamocon], Las I, etc. ■ Line selection and non-selection by the drive circuit can be controlled at a binary level, and unipolar Since only a power source is required, effects such as the ability to simplify the configuration of the drive circuit can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the conventional driving method, FIG. 2 is a circuit diagram for implementing the method of the present invention, and FIG. 3 is a diagram for explaining the driving method for the circuit shown in FIG. In the figure, C11 to C33 are liquid crystal cells/Lz, Qyl'l ~
QY32 and QXIl~Qχ32 are IC drivers, Y1
-Y3 are scanning signal supply lines, and X1 to x3 are data signal supply lines. Patent applicant Fujitsu Limited

Claims (1)

[Claims] When driving a liquid crystal panel, the reference potential of the drive 11 old/8 group connected to one electrode of the liquid crystal cell formed in a matrix is changed at a predetermined period, and if the reference potential is high, low or -1- A drive circuit connected to the other electrode of the liquid crystal cell described in -1-, which selects or non-selects the electrode by superimposing a predetermined voltage of the same polarity as the reference potential during any period in which it is held at a low level; A liquid crystal panel characterized in that a predetermined voltage is applied to the corresponding other electrode from the group at the timing of one of the two levels of the reference potential to select or non-select that electrode. driving method.