Scanning signal line drive circuit, display device having the same, and driving method for scanning signal line

A display device comprising:

• a display unit in which a plurality of scanning signal lines are disposed;
• a scanning signal line drive circuit for driving the plurality of scanning signal lines;
• and
• a display control circuit supplying a clock signal which periodically repeats an on level and an off level, to the scanning signal line drive circuit, wherein
• the scanning signal line drive circuit includes a shift register having a plurality of bistable circuits which are cascade-connected to one another and sequentially making output signals of the plurality of bistable circuits active based on the clock signal,
• each of the bistable circuits comprises:
• a first driving unit connected to a first node and changing potential of the first node based on a signal received;
• a second driving unit connected to a second node and changing potential of the second node based on a signal received;
• and
• an output unit connected to the first node and the second node and, when the potential of the first node is at the on level, the potential of the second node is at the off level, and the potential of the signal received by the first driving unit is at the off level, outputting the output signal which is active based on the clock signal,
• the first driving unit has a first-node-turn-off switching element having a control terminal connected to the second node, a conduction terminal connected to the first node, and another conduction terminal to which off-level potential is supplied,
• the output unit has an output-node-turn-off switching element having a control terminal connected to the second node, a conduction terminal connected to an output node for outputting the output signal, and another conduction terminal to which off-level potential is supplied, and
• the first driving unit and the second driving unit maintain the potential of the first node and the potential of the second node at off level, respectively, in a predetermined period of two horizontal scanning periods or more in each vertical scanning period.

A driving method for a plurality of scanning signal lines by a scanning signal line drive circuit comprising a shift register including a plurality of bistable circuits which are cascade-connected to one another and sequentially making output signals of the plurality of bistable circuits active based on a clock signal which is supplied from the outside and periodically repeats an on level and an off level,

• the driving method comprising the steps of:
• receiving a signal by each of the bistable circuits and, based on the signal, changing the potential of a first node in the bistable circuit;
• receiving a signal in each of the bistable circuits and, based on the signal, changing the potential of a second node in the bistable circuit;
• and
• outputting the output signal which is active when the potential of the first node is at the on level, the potential of the second node is at the off level, and the potential of a signal received by each bistable circuit in the step of changing the potential of the first node is at the off level,
• wherein each bistable circuit comprises:
• a first-node-turn-off switching element having a control terminal connected to the second node, a conduction terminal connected to the first node, and another conduction terminal to which off-level potential is supplied;
• and
• an output-node-turn-off switching element having a control terminal connected to the second node, a conduction terminal connected to an output node for outputting the output signal, and another conduction terminal to which off-level potential is supplied,
• in the step of changing the potential of the first node, the potential of the first node is maintained at off level in a predetermined period of more than two horizontal scanning periods in each vertical scanning period, and
• in the step of changing the potential of the second node, the potential of the second node is maintained at the off level in the predetermined period.