Patent ID: 8786588

Claim:
A method for driving a display device comprising a driver circuit portion and a pixel portion comprising n (n is a natural number) pixels, the driver circuit portion comprising a first driver circuit and a second driver circuit, wherein each of the n pixels comprises a transistor, and wherein a channel formation region of the transistor comprises an oxide semiconductor layer, comprising the step of: performing operation N (N is a natural number) times in a still image display mode for displaying a still image in the pixel portion, the operation comprising: supplying a first driving signal and a first power supply voltage to the first driver circuit; supplying a second driving signal and a second power supply voltage to the second driver circuit; supplying a scan signal to the n pixels from the first driver circuit; supplying an image signal to the n pixels from the second driver circuit; stopping supply of the second driving signal and the second power supply voltage to the second driver circuit; and holding an image of the pixel portion based on the image signal as the still image, wherein in the case where N is greater than or equal to 2, a K-th (K is a natural number greater than or equal to 2 and less than or equal to N) period of stopping supply of the second driving signal and the second power supply voltage to the second driver circuit is set longer than a (K−1)-th period of stopping supply of the second driving signal and the second power supply voltage to the second driver circuit.