Abstract: Disclosed is a gate shift register, which can perform a bi-directional shift operation with a reduced number of switching devices. The gate shift register includes a plurality of stages to receive a plurality of gate shift clocks and sequentially output a scan pulse. A kth stage includes a scan direction controller including first and second forward TFTs and first and second reverse TFTs to convert a scan direction in response to carry signals of previous stages input through first and second input terminals and carry signals of next stages input through third and fourth input terminals, a node controller including first to eighteenth TFTs to control charging and discharge operations of Q1, Q2, QB1 and QB2 nodes, and an output unit including first and second pull-up TFTs and first to fourth pull-down TFTs to output two scan pulses based on voltage levels of the Q1, Q2, QB1 and QB2 nodes.

Abstract: Disclosed is a gate shift register, which can perform a bi-directional shift operation with a reduced number of switching devices. The gate shift register includes a plurality of stages to receive a plurality of gate shift clocks and sequentially output a scan pulse. A kth stage includes a scan direction controller including first and second forward TFTs and first and second reverse TFTs to convert a scan direction in response to carry signals of previous stages input through first and second input terminals and carry signals of next stages input through third and fourth input terminals, a node controller including first to eighteenth TFTs to control charging and discharge operations of Q1, Q2, QB1 and QB2 nodes, and an output unit including first and second pull-up TFTs and first to fourth pull-down TFTs to output two scan pulses based on voltage levels of the Q1, Q2, QB1 and QB2 nodes.