In an active matrix type liquid crystal display, during a non-display period such as the horizontal blanking interval or the vertical blanking interval wherein no pixel TFT is selected, the voltage of the opposing electrode is changed so that the power consumption is reduced with application of sufficient voltage to the liquid crystal and without increasing the amplitude of the display data. Also, a change alleviating voltage VM is applied during the change in the opposing electrode voltage to data lines for supplying display data to each of pixel TFTs during the display period, in order to prevent changes in the potential of the data lines caused by the change in the opposing electrode voltage and large reverse bias from being loaded to switches Hsw for outputting display data to the data lines.
A liquid crystal display device includes a pixel electrode to which a video signal is supplied and a counter electrode to which a reference signal is supplied in each pixel. In the display device a positive-side gray scale voltage and a negative-side gray scale voltage are formed. The positive-side gray scale voltage and the negative-side gray scale voltage are formed with respect to the reference signal such that an average value of the positive-side gray scale voltage and the negative-side gray scale voltage is increased along with an increase of the signal amplitude of the video signal in the vicinity of the minimum thereof, the average value is decreased along with the further increase of the signal amplitude of the video signal, and the average value is increased along with an increase of the amplitude of the video signal in the vicinity of the maximum thereof.
