Patent ID: 8265222
Filing Date: 2012-09-11
Classification: G11C

Abstract:
1. A shift register comprising a plurality of stages to sequentially output scan pulses through respective output terminals, wherein each of the stages comprises: a pull-up switching unit controlled based on a signal state of node, and connected between the output terminal and any one among a plurality of clock transmission lines to transmit the clock pulses provided with sequential phase differences; and a node controller to control the signal state of node, and to discharge the node by using the clock pulse from any one among the plurality of clock transmission lines; wherein the node controller of a ‘n’th stage comprises: a first switching unit controlled by the scan pulse from a ‘n−2’th stage and connected between the node and a charging voltage source transmission line to transmit a charging voltage source; and a second switching unit controlled by the scan pulse from a ‘n+2’th stage and connected between the node and any one among the plurality of clock transmission lines, a third switching unit which is controlled by the clock pulse from any one among the plurality of clock transmission lines, and is connected between the node and the output terminal of a ‘n−1’th stage; a fourth switching unit; wherein the second switching unit is turned-on for a non-active state of the clock pulse of the clock transmission line connected to the second switching unit, and the second switching unit and the pull-up switching unit are connected to the same clock transmission line; wherein the clock pulse supplied to the third switching unit and the scan pulse supplied from the output terminal of the ‘n−1’th stage have the same phase; wherein the ‘n’th stage further includes a first pull-down switching unit which is controlled by a signal state of the output terminal, and is connected between the output terminal and any one of the clock transmission lines; wherein the first pull-down switching unit, the second switching unit and the pull-up switching unit are connected to the same clock transmission line; wherein the fourth switching unit included in start stages being enabled by a start pulse is controlled by a first control signal having an active state once for one frame period, and is connected between the node and a control signal transmission line to transmit a second control signal; and the second control signal corresponds to a discharging voltage source or a signal whose phase is inverted by 180° with respect to the first control signal; wherein the fourth switching unit included in the remaining stages except the start stages is controlled by the start pulse, and is connected between the node and the discharging voltage source.