Patent ID: 6646637
Filing Date: 2003-11-11
Classification: G09G

Abstract:
A liquid crystal display device comprising a pair of substrates at least one of which is transparent; a liquid crystal layer sandwiched between the substrates; a display region; and a periphery circuit for driving the display region both of which are mounted on one of the pair of substrates, the display region being formed by a plurality of drain lines and a plurality of gate lines arranged in a matrix shape and a plurality of thin film transistors each being disposed near the respective related matrixes and the periphery circuit being provided with a driving circuit which is permitted to receive digital image signal inputs, wherein the driving circuit is provided with a plurality of D/A conversion circuits each being constituted by a plurality of switches each having substantially the same ON resistance and a control circuit which controls ON and OFF of the switches in such a manner that at a time of D/A conversion operation a plurality of switches in same number are turned ON for respective input signals representing respective gradations; wherein the D/A conversion circuit is constituted by a plurality of switch groups each being constituted by a plurality of switches connected in parallel, one terminals of the respective switch groups are respectively connected to different distribution lines being supplied of respectively different reference voltages, the other terminals of the switch groups are connected in common to constitute a voltage output portion, and the control circuit controls to turn ON a predetermined plurality number n of switches among one or two of the switch groups at the same time during D/A conversion operation.