JPH05216435A - Driving method for liquid crystal display device - Google Patents

Abstract

PURPOSE:To decrease flickers by setting plural pieces of data lines connected to the same clot as one set, driving the data lines of the same set with the in-phase as the phase of a common electrode voltage and driving the data lines of the adjacent sets with the antiphase. CONSTITUTION:The voltage to be impressed to the set of three pieces of the data line connected to the set of liquid crystal picture elements constituting the dot is supplied with the same polarity as the polarity the central value of the amplitude of the impressed voltage, to the data lines driving the dot. The impressed voltage is applied to three pieces of the data line driving the dots adjacent to this dot in such a manner that the polarity is reversed from the above-mentioned polarity. Namely, the signals are so delivered to bus lines that the data signals supplied to the same dot, for example, R(red) 1, G(green) 1, B(blue) 1 have the same polarity as the polarity of the common electrode voltage and the data signals supplied to the adjacent dots, for example, the set of R1, G1, B1 and the set of R2, G2, B2 have the polarity reverse from each other with respect to the polarity of the common electrode voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method for a color liquid crystal display device.

[0002]

2. Description of the Related Art As a factor that deteriorates the image quality of a liquid crystal display device, screen flicker called flicker has become a problem. This is because the DC offset voltage of ΔV is superimposed on the AC voltage that actually drives the liquid crystal as shown in FIG. 4, so the voltage applied to the liquid crystal changes between the periods A and B of FIG. However, as a result, the brightness changes.

FIGS. 5 and 6 show the potential of each data line with respect to the potential of the common electrode (almost the same as the center value of the amplitude of the voltage applied to the data line) for each frame when driving the voltage effect transistor driving liquid crystal display device. It is a figure showing what kind of value it takes. The symbol ○ in the figure indicates that the potential of the data line has a positive value with respect to the potential of the common electrode, and ×
Indicates that the potential is negative with respect to the potential of the common electrode.

For example, if the polarities of the voltages of the data lines with respect to the common voltage are all the same during one frame operation from the first gate to the 2Nth (N is a natural number) gates as shown in FIG. 5, as shown in FIG. When a voltage is applied to the 2M-1th frame and the 2Mth frame (M is a natural number), the voltage difference across the liquid crystal is 2ΔV. As a result, the same luminance change occurs on the entire screen and its cycle is It can be seen that one frame period is reached.

In order to avoid such flicker, a driving method as shown in FIG. 6 has been proposed. This method
3, ... 2N-1 voltage applied to the first data line and 2,
4, ... The polarity of the voltage applied to the Nth data line is opposite to that of the common electrode voltage, and this polarity is switched every one frame period to cancel the flicker on the entire screen. The flicker is not visible.

[0006]

However, in the conventional driving method for the liquid crystal display device, since it is necessary to invert the polarity of the data signal every other line, as shown in FIG. It is necessary to provide a circuit 14 for separating each color signal and storing it in a memory, reversing the polarity with respect to the common electrode voltage for every other data line, rearranging again as a signal for one pixel and sending it to the liquid crystal drive circuit. .. Further, when the input signal is an analog signal, it is necessary to perform A-D conversion of the RGB signal once in order to rearrange the signals, rearrange the rearranged signals, and then perform the D-A conversion again and send the converted signals to the liquid crystal display unit 12. .. Therefore, conventionally, there has been a problem that the rearrangement operation of the RGB signals makes the scale of the signal control circuit 20 large and complicated.

[0007]

According to a method of driving a liquid crystal display device of the present invention, liquid crystal is filled between two translucent insulating substrates, and liquid crystal pixels are selected on one or both inner surfaces of the substrates. Scanning lines and data lines for applying a driving voltage to the liquid crystal pixels are arranged in a matrix, and the liquid crystal pixels have red (R) or green (G) or blue (B).
And a drive circuit for applying a voltage to the liquid crystal display section, the liquid crystal display section having dots formed by the set of the three liquid crystal pixels including the red, green, and blue color filters. In the liquid crystal display device, the applied voltage to the set of three data lines connected to the set of liquid crystal pixels forming the dots is set to the center of the amplitude of the applied voltage to the data lines driving the dots. It is characterized in that the applied voltage is supplied so as to have the same polarity with respect to the value, and the three data lines that drive the dot adjacent to the dot have a polarity opposite to the polarity.

[0008]

According to the driving method of the present invention, a plurality of data lines connected to the same dot are set as one set, the data lines of the same set are driven in the same phase with respect to the common electrode voltage, and the data lines of the adjacent set are different from each other. By driving in the reverse phase, the brightness difference in pixel units caused by the offset voltage ΔV is canceled in the entire screen, and flicker is reduced. At this time, the signals for one dot are simultaneously sampled in the same phase in the control circuit, so that one set of signals is separated for each color signal as in the conventional driving method, and the polarity of the signal with respect to the common electrode voltage is classified by color. It is characterized in that flicker can be reduced with a simple configuration that does not require a circuit for sampling and rearranging again as one set of signals.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a thin film field effect transistor (hereinafter abbreviated as TFT) active matrix type liquid crystal display device using the present invention, and FIG. 2 shows signals for realizing the driving method of the present invention. The data signal control circuit is shown in FIG. 3, which is a signal wave system diagram showing the voltage applied to the data lines in the 2M-Zth frame and the 2Mth frame in each signal line of FIG.

In FIG. 1, 1 is a scanning line driving circuit for transmitting an operation signal, 2 is a data line driving circuit for supplying image signals to pixels, and 3 and 4 are signals of the scanning line driving circuit 1 and the data line driving circuit 2. Line for supplying the pixel to the pixel, 5
Is a TFT having a function of selecting a signal to be supplied to a pixel,
6 is a pixel electrode, 7 is a liquid crystal, and 8 is a common electrode. In the case of the present embodiment, the dots are composed of three colors of RGB.

FIG. 2 is a diagram showing a signal control circuit for generating a signal for driving the liquid crystal display device of FIG. 1, and is composed of only a liquid crystal drive signal generation circuit 11. As described above, by simultaneously sampling in the data precursor circuit 2 in units of RGB dots without performing RGB decomposition, R
The driving method of the present invention can be realized by a driving circuit having a simple configuration in which the GB signal rearranging circuit is omitted.

As shown in FIG. 3, data signals (for example, R1, G1, B1) supplied to the same dot have the same polarity with respect to the common electrode voltage, and data signals supplied to adjacent dots (for example, R1). , G1, B1 pair and R2, G
2 and B2) is applied to the liquid crystal display device configured as shown in FIGS. 1 and 2 by applying a signal supply method for transmitting a signal to the bus line so that the signals have opposite polarities with respect to the common electrode voltage. It is possible to obtain a display with reduced flicker with a simple control circuit configuration.

In this embodiment, an example of an active matrix type liquid crystal display device using a thin film field effect transistor for driving a pixel electrode has been described.
The present invention is not limited to this, but can be applied as long as the scanning lines and the data lines are in a matrix arrangement.

According to the driving method of the present invention, 400 gate lines are used,
The present invention was applied to the case where an active matrix type liquid crystal display device using a thin film field effect transistor composed of 640 drain lines RGB each was driven by an interlace of 60 Hz. As a result, when the drive method of the present invention is used, the flicker is reduced to the same level as the conventional method, although the peripheral drive circuit is simplified as compared with the conventional drive method for reducing flicker. The fatigue level of the user of the liquid crystal display device was reduced.

[0015]

As has been described above, according to the liquid crystal display device of the present invention, a driving circuit having a simpler structure than the conventional one is used, a flicker is not visually recognized, and a high image quality display with less fatigue for a display user. There is an effect that a liquid crystal display device capable of achieving the above can be obtained.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram of a liquid crystal display device using a driving method of the present invention.

FIG. 2 is a diagram showing a data signal control circuit for realizing the driving method of the present invention.

FIG. 3 is a signal waveform diagram of a data line of the present invention.

FIG. 4 is a drive waveform diagram of liquid crystal pixels.

FIG. 5 is a diagram showing the polarities of pixel voltages.

FIG. 6 is a diagram showing polarities of pixel voltages.

FIG. 7 is a data signal control circuit diagram for realizing a conventional driving method.

[Explanation of symbols]

 1 scanning line drive circuit 2 data line drive circuit 3 scanning line 4 data line 5 TFT 6 pixel electrode 7 liquid crystal 8 common electrode 9 data signal voltage 10 common electrode voltage 11 liquid crystal drive voltage generation circuit 12 liquid crystal display section 14 RGB signal rearrangement circuit

Claims (1)

[Claims] 1. A liquid crystal is filled between two translucent insulating substrates, and a scanning line for selecting a liquid crystal pixel on one or both inner surfaces of the substrate and a driving voltage for applying a driving voltage to the liquid crystal pixel. Data lines are arranged in a matrix, red, green, or blue color filters are arranged in the liquid crystal pixels, and dots are formed by a set of three liquid crystal pixels including the red, green, and blue color filters. And a liquid crystal display section that forms
In a liquid crystal display device including a drive circuit that applies a signal voltage to the liquid crystal display unit, the voltage applied to a set of three data lines connected to the set of liquid crystal pixels forming the dots is The data lines that drive the dots are supplied with the same polarity with respect to the center value of the amplitude of the applied voltage, and the three data lines that drive the dots adjacent to the dots have a polarity opposite to the polarity. A method for driving a liquid crystal display device, wherein the applied voltage is supplied so that