A photo-sensitive element, a readout pixel with the photo-sensitive element, and a liquid crystal display with the readout pixels are described. The photo-sensitive element includes a switch TFT and a photo detecting device. The gate electrode of the switch TFT is electrically connected to a switch line and the source electrode of the switch TFT is electrically connected to a readout line. The photo detecting device is connected between the switch line and the drain electrode of the switch TFT for detecting the brightness of a light incident thereon. The photo detecting device is preferably a photo TFT, a photo diode, or a light sensitive resistor. The photo TFT and the switch TFT are preferably amorphous silicon transistors. The switch line is preferably a gate line disposed on the TFT array substrate of the liquid crystal display.