Patent ID: 6856307

Claim:
A semiconductor display device comprising: a source signal line drive circuit unit constituted by plural thin-film transistors; a gate signal line drive circuit unit constituted by plural thin-film transistors; and a pixel unit in which plural pixel thin-film transistors are arranged like a matrix; wherein, the gate signal line drive circuit unit has at least one tristate buffer and one gate selection pulse change-over switch per a gate signal line; the tristate buffer has: a first circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor; and a second circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor; the source region of the n-channel thin-film transistor in the first circuit is electrically connected, at a first connection point, to the source region of the p-channel thin-film transistor of the second circuit; a first power source is electrically connected to the source region of the p-channel thin-film transistor of the first circuit; a second power source having a potential lower than that of the first power source is electrically connected to the first connection point; a third power source having a potential lower than the second power source is electrically connected to the source region of the n-channel thin-film transistor of the second circuit; and an output signal line of the first circuit and an output signal line of the second circuit are both electrically connected to the gate signal line at a second connection point.