Patent ID: 7333586
Filing Date: 2008-02-19
Classification: G09G,G11C

Abstract:
1. A shift register having a plurality of stages each which output an output signal through an output signal line by using any three of a first voltage supply source, a previous stage's output signal, a next stage's output signal, and first to fourth clock signals, comprising: a transistor to output the first clock signal through the output signal line in response to a logic value of a Q node; a transistor to supply a supply voltage from the first voltage supply source to the output signal line in response to a logic value of a Qb node; a Q node controller to control the logic value of the Q node in response to anyone of the previous stage's output signal and the next stage's output signal; a Qb node controller to control the logic value of the Qb node to alternate repeatedly between low and high by use of at least one of the second clock signal, the fourth clock signal and the logic value of the Q node when the output signal line is in a low state; wherein the Q node controller comprises a first switch connected between the Q node and the previous stage's output signal line to be controlled by the previous stage's output signal; a second switch connected between the Q node and the first voltage supply source to be controlled by the next stage's output signal; and a third switch connected between the first voltage supply source and the Q node to be controlled by the logic value of the Qb node; and wherein the Qb node controller comprises, A fourth switch connected between a second voltage supply source from which a second voltage is supplied, and the Qb node to be controlled by the fourth clock signal; a fifth switch connected between the Qb node and the first voltage supply source to be controlled by the second clock signal; a sixth switch connected between the Qb node and the first voltage supply source to be controlled by the previous stage's output signal; and a seventh switch connected between the Qb node and the first voltage supply source to be controlled by the logic value of the Q node.