Optical sensor and display device provided with the same

摘要

The present invention provides an optical sensor at least some part of which is formed monolithically in an active matrix substrate of a display device. In order to detect ambient light with high accuracy by eliminating the influences of stray light and of property variations between photodetecting elements, the optical sensor includes a detection photodiode (11) and a reference photodiode (12) covered with a shielding film (15). The optical sensor further includes a differential amplifier (16) one input terminal of which is connected to the cathode of the detection photodiode (11) and the other input terminal is connected to the cathode of the reference photodiode (12), an integration capacitor (19) and a reset switch (22). The optical sensor further includes a comparator (21) and a low-pass filter (20) for making the electric potentials of the anodes of the reference photodiode (12) and detection photodiode (11) larger than the electric potential of the cathode of the reference photodiode (12) by the open-circuit voltage VOC.