False contouring during display by time division gray scales can be
prevented with high efficiency. The order of appearance of subframe
periods, and the times at which the subframe periods begin, are changed
between pixels driven by odd number gate signal lines and pixels driven
by even number gate signal lines. For example, assume that display is
performed in a display period T.sub.r1 of a subframe period SF.sub.1, a
display period T.sub.r2 of a subframe period SF.sub.2, and a display
period T.sub.r3 of a subframe period SF.sub.3. The order of appearance of
the display periods is changed between pixels driven by the odd number
gate signal lines (B1) and pixels driven by the even number gate signal
lines (B2). Although the non-light emitting display periods (display
periods T.sub.r3, T.sub.r2, and T.sub.r1) are continuous over nearly one
frame period in the odd number lines of pixels when there is a gray scale
change, non-light emission and light emission are repeated alternately at
the same time for the even number lines of pixels. Accordingly, the
brightness of the above light emission is averaged by human eyes, and
therefore the generation of unnatural dark lines (false contouring) can
be suppressed.