A compensative driving method for common electrode voltage distortions in TFT-LCDs

The authors describe results of investigation and analysis of common electrode (counter electrode) voltage distortions which cause horizontal-crosstalk and degradation of the contrast ratio. A novel driving method, in which an AC voltage is applied independently to storage capacitor bus-lines, is proposed to compensate the distortions. Its effect has been confirmed by waveform observation, horizontal-crosstalk observation, and V-T characteristics in both common-DC and common-alternation drives. In the common-alternation drive, it has been further confirmed that the driving method can compensate for distortion of voltages across the liquid crystal layer which does not occur in the common-DC drive.<>