CROSS-REFERENCE

This application is based upon and claims priority to Chinese Patent Application No. 201910031670.2, filed on Jan. 14, 2019, the entire contents thereof are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of display technologies, and more particularly, to a method and a device for compensating a common voltage, and a display device.

BACKGROUND

At present, liquid crystal displays (LCDs) are more and more widely used. The liquid crystal display utilizes a voltage difference between a common electrode and a pixel electrode to drive the liquid crystal molecules to rotate, thus realizing the image display. In the liquid crystal display, due to the presence of the coupling capacitance between the common electrode and the data line, when the data signal provided by the data line changes, the voltage across the coupling capacitor abruptly changes, causing the common voltage of the common electrode to fluctuate, which is difficult to be maintained stable. It can further cause abnormal voltage difference between the common electrode and the pixel electrode. Thus, problems such as afterimage and crosstalk on the liquid crystal display can arise, which affects the display effect. Therefore, it is necessary to compensate for the common voltage.

To compensate the common voltage, a feedback signal line is usually utilized to monitor and feed the actual fluctuation of the common voltage back. Then the common voltage is compensated according to the feedback signal fed back by the feedback signal line. However, the conventional compensation for the common voltage has a problem of low accuracy, resulting in abnormalities such as horizontal stripes on the display screen.

SUMMARY

The present disclosure provides a method and a device for compensating a common voltage, and a display device.

A first aspect of the present disclosure provides a method for compensating a common voltage, which is applied to a display device. The method includes generating a feedback signal by acquiring a real-time monitoring result of a feedback signal line on a common voltage. The feedback signal includes a plurality of time periods. Each of the time periods includes a first sub-period in which the feedback signal is interfered by the periodic signal and a second sub-period in which the feedback signal is not interfered by the periodic signal. The method includes processing the feedback signal to eliminate distortion of the feedback signal caused by interference of the periodic signal in the first sub-period. The method includes compensating for the common voltage according to the feedback signal processed.

In some arrangements, processing the feedback signal to eliminate distortion of the feedback signal caused by interference of the periodic signal in the first sub-period includes: in the first sub-period, changing the feedback signal to 0; and in the second sub-period, keeping the feedback signal unchanged.

In some arrangements, the feedback signal includes n time periods, where n is a positive integer greater than 1. Processing the feedback signal to eliminate distortion of the feedback signal caused by interference of the periodic signal in the first sub-period includes: in the second sub-period of the j-th period, keeping the feedback signal unchanged, and recording the waveform of the feedback signal in the second sub-period, where 1≤j<n; in the first sub-period of the (j+1)-th period, according to the recorded waveform of the second sub-period of the j-th period, fitting the waveform of the feedback signal in the first sub-period; and changing the feedback signal to the waveform signal obtained by the fitting.

In some arrangements, processing the feedback signal to eliminate distortion of the feedback signal caused by interference of the periodic signal in the first sub-period includes determining the first sub-time period and the second sub-time period according to a timing of the periodic signal.

In some arrangements, the method for compensating a common voltage further includes a block of setting a time length of the first sub-period before a terminal product leaves the factory. The block includes: measuring, for a plurality of time, a duration time length in which the periodic signal interferes the feedback signal to cause the feedback signal to be distorted each time; and calculating an average value of the plurality of duration time lengths measured, and setting the average value as the time length of the first sub-period.

In some arrangements, the time length of the first sub-period ranges from 0.5 μs to 2 μs.

In some arrangements, generating a feedback signal by acquiring a real-time monitoring result of a feedback signal line on a common voltage includes: acquiring a real-time monitoring result of a feedback signal line on a common voltage, the real-time monitoring result reflecting an actual value of the common voltage at each time point; and calculating a difference between the actual value of the common voltage at each time point and a reference value of the common voltage, and generating the feedback signal according to the calculated difference.

A second aspect of the present disclosure provides a device for compensating a common voltage, which is applied in a display device. The device for compensating the common voltage includes a signal generator coupled to a feedback signal line, and configured to generate a feedback signal by acquiring a real-time monitoring result of the feedback signal line on the common voltage from the feedback signal line. The feedback signal includes a plurality of time periods, each of the time periods including a first sub-period in which the feedback signal is interfered by the periodic signal and a second sub-period in which the feedback signal is not interfered by the periodic signal. The device for compensating the common voltage includes a signal processor coupled to the signal generator and configured to process the feedback signal generated by the signal generator to eliminate distortion of the feedback signal caused by the interference of the periodic signal in the first sub-period. The device for compensating the common voltage includes a common voltage compensator coupled to the signal processor and configured to compensate for the common voltage according to the feedback signal processed by the signal processor.

In some arrangements, the signal processor includes an input end, an output end, and a switch. The input end is coupled to the signal generator. The output end is coupled to the common voltage compensator. The switch is coupled between the input end and the output end, and the switch is also coupled to the periodic signal line. The switch is configured to receive the periodic signal of the periodic signal line, switch off the line between the input end and the output end in the first sub-period, and switch on the line between the input end and the output end in the second sub-period according to the timing of the periodic signal.

In some arrangements, the signal processor includes an input end, an output end, and a fitting unit. The input end is coupled to the signal generator. The output end is coupled to the common voltage compensator. The fitting unit is coupled between the input end and the output end, and the fitting unit is also coupled to the periodic signal line. The fitting unit is configured to receive the periodic signal of the periodic signal line. According to the timing of the periodic signal, the fitting unit is configured to transmit the feedback signal from the input end to the output end in the second sub-period and record the waveform of the feedback signal in the second sub-period. In the first sub-period, the fitting unit is configured to fit the waveform of the feedback signal in the first sub-period according to the recorded waveform of the second sub-period adjacent to the first sub-period and before the first sub-period. The fitting unit is configured to transmit the waveform signal obtained by the fitting to the output end.

A third aspect of the present disclosure provides a display device including the device for compensating a common voltage provided in the second aspect.

