a lcd panel comprises a first substrate and the second substrate . the first substrate comprises a pixel , a sensor pad arranged adjacent to the pixel , a switch electrically coupled to the sensor pad , a pixel gate line electrically coupled to the pixel , a sensor gate line electrically coupled to the switch , and a readout line . the second substrate comprises a sensing device protruding form the second substrate , and a conducting layer covering on the sensing device and electrically coupled to a predetermined power . when assembling the second substrate with the first substrate , the sensing device is opposite to the sensor pad . when pressing the second substrate , the conducting layer covering on the sensing device contacts with the sensor pad . the sensor gate line controls on / off state of the switch to determine whether the sensor pad is electrically conducted with the readout line .