Patent ID: 8098345

Claim:
A liquid crystal display device, comprising: an active matrix substrate in which at least a scanning signal line, a video signal line, a thin film transistor element for driving a pixel, a pixel electrode and a storage capacitor wiring for retaining an electric potential of the pixel electrode are provided; a counter substrate facing the active matrix substrate; a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate; and a two-dimensional sensor array in which optical sensor circuits are two-dimensionally positioned, the optical sensor circuits each including at least a photodiode that outputs a signal corresponding to quantity of light that the photodiode receives, a thin film transistor element and a charge-storage element, the thin film transistor having a gate electrode, a source electrode and a drain electrode, the gate electrode, the source electrode and the drain electrode being connected to a cathode electrode of the photodiode, a voltage supply wiring and an optical sensor output wiring, respectively, the charge-storage element having two electrodes, one of the two electrodes being electrically connected to the cathode electrode of the photodiode, and the other of the two electrodes being electrically connected to a drive wiring for supplying a drive signal to the charge-storage element, and the storage capacitor wiring also serving as at least one of the drive wiring for driving the charge-storage element and the voltage supply wiring for supplying a voltage to the thin film transistor element.