in power saving luminance control that the maximum luminance of one field is varied according to an average luminance level of an image , the luminance of a subfield at the minimum luminance level is fixed to a certain value without depending upon the variation of the maximum luminance of one field . hereby , even if luminance control that the maximum luminance of one field is enhanced in an image the average luminance level of which is low is made , a gradation characteristic in a low luminance region is improved .