To provide a display device having an input function that is not dependent on the light environment, multiple sensor pixel circuits that detect light in a specified detection period and hold the light amount when not in the specified detection period are disposed in a pixel region. In a frame in which input is performed using the sensor pixel circuits, a backlight is lit one time for a time in a frame period, and a first detection period and a second detection period are set one time each in the frame period. The difference between the light amount in the first detection period and the light amount in the second detection period is obtained using a difference circuit. The backlight is in an extinguished state at the beginning of the first detection period, and lighting of the backlight is started at a time during the first detection period.