Patent ID: 8208598

Claim:
A shift register having a plurality of stages provided on two sides of a display panel for providing scan signals, wherein each stage of the shift register on one side of the display panel comprises: a first level control unit for providing a first clock signal to an output terminal; a first driving unit coupled to an input terminal of the first level control unit via a first node for providing a first control signal, wherein the first driving unit turns on the first level control unit in response to a front edge of an input signal and turns off the first level control unit when an output signal of the next stage is higher than the level of a first voltage that is input to the first level control unit; a second level control unit for providing the first voltage to the output terminal; a second driving unit for turning off the second level control unit in response to the front edge of the first control signal and turning on the second level control unit in response to the rear edge of the first control signal; and a third level control unit for providing the first clock signal to the output terminal when the level of the first control signal of the next stage is higher than the level of the first clock signal that is input to the third level control unit, wherein: when both the signal at the output terminal and the first control signal are at high levels, the first clock signal is also at a high level.