Liquid crystal display

Abstract

There is provided a driving circuit including active matrix type liquid crystal display capable of decreasing the electric power consumption of CMOS buffers contained in a scanning line driving circuit and picture signal line driving circuit. The liquid crystal display has an active matrix type liquid crystal display elements comprising switching elements connected to a plurality of scanning lines and a plurality of picture signal lines perpendicular to the scanning lines. The liquid crystal display includes a digital circuit wherein at least one of a scanning line driving circuit for applying a scanning pulse to the switching elements via the scanning lines and a picture signal line driving circuit for applying a picture signal to the picture signal lines comprises one stage of CMOS buffer or a plurality of CMOS buffers connected in multi stages, the CMOS transistor or each of the CMOS transistors including an N-type thin-film transistor and P-type thin-film transistor which are formed on the same substrate. In the liquid crystal display, one transistor, which has a longer off-state time during operation of the circuit, of the N-type thin-film transistor and P-type thin-film transistor constituting the CMOS buffer, has a longer gate length than that of the other transistor.