Patent ID: 6567062
Filing Date: 2003-05-20
Classification: G09G

Abstract:
An active matrix type liquid crystal display apparatus comprising:a plurality of common electrodes and a plurality of gate electrodes, both of which are intersected respectively, and a plurality of drain electrodes in parallel with said common electrodes, formed on one of inner surfaces of two substrates oppositely arranged through a liquid crystal layer; a display pixel unit having a plurality of pixels, each of which includes a three-terminal switching element and a liquid crystal cell at each of intersection points of said plurality of common electrodes and said plurality of gate electrodes; and a peripheral circuit for applying a predetermined voltage to each of said common electrode, said gate electrode and said drain electrode; wherein a first terminal of said switching element is connected to said drain electrode; a second terminal of said switching element is connected to said liquid crystal cell an opposite side of which is connected to said common electrode; and a third terminal of said switching element is connected to said gate electrode; whereby said switching element is switched into an ON state when an electric potential difference between a voltage applied to said gate electrode and a voltage applied to said common electrode becomes a predetermined value; an electric potential difference between a voltage applied to said drain electrode and said voltage applied to said common electrode is applied to said liquid crystal cell in the ON state of said switching element; and an electric potential difference applied at an end of the ON state of said switching element is held until a next ON state; wherein said peripheral circuit includes: a scan signal driving circuit for applying an active state of a scan line signal indicative of a scan line to said common electrode in sequence on one scanning time-period basis; a gray-scale voltage circuit for applying a gray-scale voltage to said drain electrode; and a data signal driving circuit for applying, to said gate electrode, a gray-scale voltage control signal having a pulse-width in accordance with gray-scale information as display data of a pixel applied by the active state of the scan line signal; said gray-scale voltage circuit includes: a voltage waveform generating circuit for generating a voltage, a waveform of which is varied with a time predetermined by a characteristic; and a plurality of gray-scale voltage selecting circuits arranged on each of scan lines for applying, to said drain electrode, the voltage waveform generated by said voltage waveform generating circuit for a time-period corresponding to the pulse-width of the gray-scale voltage control signal in a case where the scan line has been selected.