FIGS. 5A, 5B are a block diagram and a time chart, respectively, showing still another constitution for obtaining the common line driving voltage VCS in another embodiment of the invention, corresponding to FIG. 4A, 4B. In the embodiment, the scanning signal VG1 from the scanning signal line Y1 in the first row is used as a common line driving voltage VCS of the return circuits of the condensers C