Tn liquid crystal display device and touch control method thereof

A method of controlling a twisted nematic liquid crystal display device, for performing detection of touch signal, the method comprising:

• dividing a time-sharing period during display into a first duration and a second duration, wherein during the time-sharing period, the common electrode layer is configured to detect a touch signal and to provide a common electrode signal, wherein the second duration is shorter than a retention time of liquid crystal molecules and is longer than or equal to a scanning time for one detection of the touch signal by the common electrode layer, and wherein the retention time of liquid crystal molecules is a time period during which the liquid crystal molecules maintain a previous state when a driving voltage of the common electrode layer changes;
• during the first duration, applying a same common potential to a plurality of sensing electrodes, to a plurality of driving electrodes, and to a plurality of dummy electrodes of the common electrode layer to achieve normal display;
• and
• during the second duration, grounding the dummy electrodes and applying a driving voltage for touch detection to the sensing electrodes and to the driving electrodes of the common electrode layer.