Display device with touch sensor, and drive method for the device

A driving method for driving a touch-sensored display device which includes:

• a display panel including an active matrix substrate having a plurality of pixel electrodes, a display medium layer, and a counter substrate disposed on a viewer side of the active matrix substrate via the display medium layer, the counter substrate having a counter electrode which opposes the plurality of pixel electrodes;
• a display panel driving circuit for supplying display signal voltages to the plurality of pixel electrodes, and supplying to the counter electrode a common voltage which undergoes periodic inversion in polarity;
• a transparent conductive film for position detection, placed so as to oppose the counter electrode via the counter substrate;
• a plurality of terminals connected to different points on the transparent conductive film for position detection;
• an AC voltage generation circuit for supplying an AC voltage for position detection to each of the plurality of terminals;
• and a plurality of noise-cut current signal generation circuits each being connected to one of the plurality of terminals,
• wherein the driving method comprises:
• a step of supplying a horizontal synchronizing signal to the display panel driving circuit;
• a step of supplying to the display panel the common voltage, the polarity of the common voltage being inverted at a point in time after the lapse of a predetermined period from a pulse of the horizontal synchronizing signal;
• a step of generating a strobe signal having a pulse which rises or falls before the predetermined period elapses since a pulse of the horizontal synchronizing signal and which falls or rises after the predetermined period has elapsed;
• a step of generating a plurality of noise-cut current signals obtained by eliminating a noise ascribable to an induced voltage that occurs on the transparent conductive film responsive to the common voltage from a current flowing from each of the plurality of terminals by using the strobe signal, wherein the induced voltage is induced on the transparent conductive film for position detection;
• and
• a step of, based on the plurality of noise-cut current signals, generating position data of a contact point which is formed directly or indirectly on the transparent conductive film for position detection.