A liquid crystal display panel includes a touch sensor and the touch sensor includes a plurality of x-axis read-out lines, a plurality of y-axis read-out lines crossing the x-axis read-out lines, a plurality of sensor units provided in a plurality of regions defined by the x-axis read-out lines and the y-axis read-out lines. Each sensor unit comprises a reset unit that outputs a sampling voltage based on a reset voltage, a capacitance detector that generates a modified sampling voltage from the sampling voltage based on a variation of a cell gap of the display panel caused by a touch of the display panel, a first output unit that changes an electric potential of a corresponding x-axis read-out line in response to the modified sampling voltage and a second output unit that changes an electric potential of a corresponding y-axis read-out line in response to the modified sampling voltage.