Liquid crystal display devices having improved screen clearing

Abstract

Liquid crystal display devices include an array of liquid crystal display cells arranged as a plurality of columns of display cells electrically coupled to respective data lines and a plurality of rows of display cells electrically coupled to respective gate lines. A gate line on/off voltage generator and gate line driving circuit are provided to drive at least a first gate line with a turn-on voltage of first polarity (e.g., positive voltage) and simultaneously driving at least a second gate line with a turn-off voltage of second polarity (e.g., negative voltage). First and second screen clearing circuits are also provided to improve the screen clearing capability of the liquid crystal display device. The first screen clearing circuit can be electrically coupled to the first gate line to perform the function of driving the first gate line from the turn-on voltage (e.g., positive voltage) to a ground reference voltage upon termination of a power supply signal; and the second screen clearing circuit of different design can be electrically coupled to the second gate line to perform the function of driving the second gate line from the turn-off voltage (e.g., negative voltage) to the ground reference voltage upon termination of the power supply signal. These driving functions may act to increase the conductivity of the TFTs in the 'off' display cells and thereby improve the rate of charge leakage from the storage capacitors and the liquid crystal capacitors therein.