Liquid crystal display and driving method thereof

Abstract

A liquid crystal display includes a gate driver, a data driver and a pixel matrix. The gate driver is for outputting a plurality of gate signals successively. The data driver is for providing a plurality of data signals. The pixel matrix includes a number of pixels. Each pixel includes a first sub-pixel, a second sub-pixel and a voltage coupling device. The voltage coupling device is coupled between the first sub-pixel and the second sub-pixel such that pixel voltages of the first sub-pixel and the second sub-pixel are different and have relevant variation.

What is claimed is: 
     
         1 . A method for driving a liquid crystal display, the liquid crystal display comprising a gate driver, a data driver and a plurality of rows of pixels, the gate driver outputting a plurality of gate signals, the data driver outputting a plurality of data signals, each of the pixels comprising a first sub-pixel and a second sub-pixel, the first sub-pixel having a first switch device, a first pixel electrode, a first common electrode and a first electrode, the first pixel electrode and the first common electrode forming a first storage capacitor, the second sub-pixel having a second switch device, a second pixel electrode, a second common electrode and a second electrode, the second pixel electrode and the second common electrode forming a second storage capacitor, the method comprising:
 (a) enabling a row of pixels according to the corresponding gate signal to turn on the first switch device and the second switch device of each pixel in the row of pixels, inputting the corresponding data signal to the first pixel electrode and the second pixel electrode and respectively providing a first voltage and a second voltage to the first electrodes and the second electrodes in the row of pixels; and   (b) after the gate signal is stopped outputting for a period of time, changing the first voltage of the first electrode of each pixel in the row of pixels to cause a common voltage of the corresponding second common electrode to be changed through a voltage coupling device between the corresponding first sub-pixel and second sub-pixel and adjusting voltages of the corresponding first pixel electrode and the second pixel electrode such that a pixel voltage of the first pixel electrode is not equal to a pixel voltage of the second pixel electrode, wherein a voltage variation ΔVp 1  of the pixel voltage of the first pixel electrode, a voltage variation ΔVp 2  of the pixel voltage of the second pixel electrode, a voltage variation ΔV 1  of the first voltage and a voltage variation ΔV 2  of the second common electrode have the following relationship: ΔVp 1 =c 1 *ΔV 1 +c 2 *ΔV 2 ; ΔVp 2 =c 3 *ΔV 1 +c 4 *ΔV 2 , and constants c 1  and c 2  are not both zero, constants c 3  and c 4  are not both zero.   
     
     
         2 . The method according to  claim 1 , wherein the step (b) further comprises changing the first voltage of each pixel in the row of pixels in a swing type. 
     
     
         3 . The method according to  claim 2 , wherein a swing period of the first voltage is much smaller than a frame time of the liquid crystal display. 
     
     
         4 . The method according to  claim 1 , wherein in the step (b), the first voltage and the second voltage vary a swing type and the first voltage has a varying direction opposite to that of the second voltage. 
     
     
         5 . The method according to  claim 1 , wherein each of the pixels comprises a red pixel, a green pixel and a blue pixel arranged successively, the red pixel and the green pixel have the same driving polarity which is opposite to that of the blue pixel, and two red pixels, two green pixels or two blue pixels corresponding to two adjacent rows of pixels have the same driving polarity. 
     
     
         6 . A method for driving a liquid crystal display, the liquid crystal display comprising a gate driver, a data driver and a plurality of rows of pixels, the gate driver outputting a plurality of gate signals, the data driver outputting a plurality of data signals, each of the pixels comprising a first sub-pixel and a second sub-pixel, the first sub-pixel having a first switch device, a first pixel electrode, a first common electrode and a first electrode, the first pixel electrode and the first common electrode forming a first storage capacitor, the second sub-pixel having a second switch device, a second pixel electrode, a second common electrode and a second electrode, the second pixel electrode and the second common electrode forming a second storage capacitor, the method comprising:
 (a) enabling a row of pixels according to the corresponding gate signal to turn on the first switch device and the second switch device of each pixel in the row of pixels, inputting the corresponding data signal to the first pixel electrode and the second pixel electrode and respectively providing a first voltage and a second voltage to the first electrodes and the second electrodes in the row of pixels; and   (b) after the gate signal is stopped outputting for a period of time, changing the first voltage of the first electrode of each pixel in the row of pixels to cause a common voltage of the corresponding second common electrode to be changed through a capacitor or a resistor connected between the corresponding first sub-pixel and second sub-pixel and adjusting voltages of the corresponding first pixel electrode and the second pixel electrode such that a pixel voltage of the first pixel electrode is not equal to a pixel voltage of the second pixel electrode, wherein a voltage variation ΔVp 1  of the pixel voltage of the first pixel electrode, a voltage variation ΔVp 2  of the pixel voltage of the second pixel electrode, a voltage variation ΔV 1  of the first voltage and a voltage variation ΔV 2  of the second common electrode have the following relationship: ΔVp 1 =c 1 *ΔV 1 +c 2 *ΔV 2 ; ΔVp 2 =c 3 *ΔV 1 +c 4 *ΔV 2 , and constants c 1  and c 2  are not both zero, constants c 3  and c 4  are not both zero;   wherein the common voltage of the second common electrode is changed with the first voltage of the first electrode by a voltage division of the capacitor or a resistor connected between the corresponding first sub-pixel and second sub-pixel.   
     
     
         7 . The method according to  claim 6 , wherein the step (b) further comprises changing the first voltage of each pixel in the row of pixels in a swing type. 
     
     
         8 . The method according to  claim 7 , wherein a swing period of the first voltage is much smaller than a frame time of the liquid crystal display. 
     
     
         9 . The method according to  claim 6 , wherein in the step (b), the first voltage and the second voltage vary a swing type and the first voltage has a varying direction opposite to that of the second voltage. 
     
     
         10 . The method according to  claim 6 , wherein each of the pixels comprises a red pixel, a green pixel and a blue pixel arranged successively, the red pixel and the green pixel have the same driving polarity which is opposite to that of the blue pixel, and two red pixels, two green pixels or two blue pixels corresponding to two adjacent rows of pixels have the same driving polarity.