SHIFT REGISTER INCLUDING STAGES COMPRISING CHARGE UNIT,DISCHARGE UNIT, AND SCAN DIRECTION CONTROL UNIT

摘要

PURPOSE: A shift register is provided to prevent distortion due to leakage current in a floating state of a Q node by latching an output signal and feeding it back to the Q node. CONSTITUTION: A shift register comprises a number of stages and is scanned bidirectionally. According to each stage(ST), a charge unit(52) charges the first supply voltage to the first node according to a clock signal. A discharge unit(54) discharges the first node according to the first start pulse or the second start pulse. A scan direction control unit(56) is connected between the charge unit and the discharge unit, and discharges the first node to different path according to a scan direction control signal. An output unit outputs one of the first and the second supply voltage as an output signal according to a voltage of the first node. A latch(60) latches the output signal and then feeds it back to the first node using the output signal and a clock signal and an inverted clock signal.