Liquid crystal display device and method for driving same

A liquid crystal display device including a liquid crystal panel with a built-in touch panel, the liquid crystal display device comprising:

• a plurality of pixel circuits each including a liquid crystal capacitance constituted by a pixel electrode and a common electrode, a memory circuit configured to store binary data, and a voltage selection circuit configured to supply either a first voltage or a second voltage to the pixel electrode in accordance with a value of the binary data stored in the memory circuit;
• a common electrode drive circuit configured to drive the common electrode;
• and
• a state control circuit configured to switch a state of the pixel electrode between a floating state and a non-floating state,
• wherein the touch panel uses the common electrode as an electrode for touch detection,
• the common electrode drive circuit supplies a pulse signal for touch detection to the common electrode in a touch detection period for detecting a touched position on the touch panel, and
• the state control circuit switches the state of the pixel electrode from the non-floating state to the floating state before a start of the touch detection period, and switches the state of the pixel electrode from the floating state to the non-floating state after an end of the touch detection period.