The invention provides a liquid crystal display panel, comprising a plurality of scan lines fabricated along a first axis, a plurality of data lines fabricated along a second axis, a first pixel and a second pixel. Each of the first and second pixels is surrounded by two adjacent scan lines and two adjacent data lines. The first pixel comprises a first thin film transistor (TFT). The second pixel comprises a second and a third TFT. The gates of the second and third TFT are electrically connected to the two adjacent scan lines surrounding the second pixel, respectively. The third TFT further comprises a source electrically connected to a photo-sensor, and a drain electrically connected to an access line fabricated along the second axis. One end of the access line is electrically connected to a signal processor via a switch.