Patent ID: 6577293
Filing Date: 2003-06-10
Classification: G09G

Abstract:
A source driving method for a liquid crystal display in a polarity inversion mode, wherein the liquid crystal display includes a plurality of source lines with capacitors, an output buffer for applying negative video signals or positive video signals to the plurality of source lines, a liquid crystal panel for expressing the video signal supplied through the source lines, and n external capacitors, wherein n is an integer no less than 2 the method comprising steps of:(a) charging the n external capacitors with stepwise voltages between an upper voltage and a lower voltage, wherein the upper voltage represents the voltage corresponding to a predetermined gray value of the positive video signal and the lower voltage represents the voltage corresponding to a predetermined gray value of the negative video signal; (b) performing stepwise polarity modulation in which odd-numbered source line capacitors are charged with stepwise polarity voltages from the n external capacitors by connecting the odd-numbered source line capacitors to the n external capacitors stepwise, and simultaneously recovering at the n external capacitors stepwise polarity voltages from the even-numbered source line capacitors by connecting the even-numbered source line capacitors to the n external capacitors stepwise such that the even-numbered source line capacitors are discharged stepwise; (c) performing stepwise polarity modulation in which even-numbered source line capacitors are charged with stepwise polarity voltages from the n external capacitors by connecting the even-numbered source line capacitors to the n external capacitors stepwise, and simultaneously recovering at the n external capacitors stepwise polarity voltages from the odd-numbered source line capacitors by connecting the odd-numbered source line capacitors to the n external capacitors stepwise such that the odd-numbered source line capacitors are discharged stepwise; and (d) performing a gray scale decision in which the voltage of the output buffer is applied to the source line capacitors whose polarity has been modulated in step (b) or step (c).