A pixel array including a plurality of scan lines and a plurality of data lines disposed crossing the scan lines to define a plurality of sub-pixel regions; at least a controlling structure, disposed in one of the sub-pixel regions and electrically connected to one of the scan lines and data lines; a plurality of sensing signal lines disposed parallel with the data lines and crossing the scan lines to define a plurality of regions having at least one first sub-region and second sub-region; at least one sensing-signal readout device disposed in the first sub-region and electrically connected with one of the scan lines and sensing signal lines; and at least one first sensing pad disposed in the second sub-region and electrically connected to the sensing-signal readout device in the second sub-region. The numbers of the sensing-signal readout devices electrically connected to the respective scan lines are the same.