Patent ID: 7508370

Claim:
A method of driving an active matrix type liquid crystal display device in which while a partial display mode and a normal display mode are switchable, when the partial display mode is selected, a predetermined display operation is carried out in a partial display area which is constituted by an arbitrarily selected number of gate lines, and a background is displayed on the remaining background display area; wherein: while the respective gate lines of said partial display area are scanned in a certain period, in such a case that said period is defined as a frame period, “k” pieces (symbol “k” is integer larger than, or equal to 1) of the partial display areas are present within 1 screen, a common electrode potential is varied 2k times within 1 frame period; a common electrode potential in a partially scanning period for scanning the partial display area is made as a constant potential with respect to a potential which constitutes a reference of a driving circuit for driving the data lines; and within a time period of at least two continued frames, a common electrode potential of a blank period other than the partially scanning period is made as a constant potential which is different from said constant potential in said partially scanning period.