Patent ID: 8121244
Filing Date: 2012-02-21
Classification: G09G,G11C

Abstract:
1. A dual shift register comprising: a first shift register configured to include a plurality of stages which sequentially output scan pulses using four clock signals with sequential and circular phases; and a second shift register configured to include a plurality of stages which form pair with the respective stages of the first shift register and sequentially output the scan pulses using four clock signals, wherein, each of the stages includes, a scan direction controller configured to respond to the scan pulses from previous and next stages and to selectively output forward and reverse direction voltages with opposite electric potentials to each other; and an output portion configured to respond to the output signal of the scan direction controller, to generate two sequential scan pulses using two of the four clock signals, and to distribute the sequential scan pulses to the previous and next stages, and a node controller configured to respond to the output signal from the scan direction controller and to control signals on first and second nodes, and wherein the output portion is configured to respond to the signals on the first and second nodes and to generate the two sequential scan pulses using the other two clock signals of the four clock signals, wherein the node controller includes: wirings configured to independently charge the output signal of the scan direction controller into the first and second nodes; a first active switching element connected between a first clock line, which transfers one of the other two clock signals of the four clock signals, and a first common node; a first switching element turned-on/off by the signal on the first node and connected between the first common node and a discharging voltage line; a second switching element turned-on/off by a signal on the first common node and connected between the first node and the discharging voltage line; a second active switching element connected between a second clock line, which transfers the other one of the other two clock signals of the four clock signals, and a second common node; a third switching element turned-on/off by the signal on the second node and connected between the second common node and the discharging voltage line; and a fourth switching element turned-on/off by a signal on the second common node and connected between the second node and the discharging voltage line.