LIGHT QUANTITY DETECTION CIRCUIT, ELECTRO-OPTICAL DEVICE, AND ELECTRONIC EQUIPMENT

PROBLEM TO BE SOLVED: To provide a light quantity detection circuit, an electro-optical device, and electronic equipment preventing a change of sensitivity of light quantity detection even when it is used with the lapse of time. SOLUTION: The light quantity detection circuit includes a TFT 11 made a conduction state by applying positive voltage with respect to source electrode d to a gate electrode; and a capacitive element 13 parallely connected with respect to a source electrode s and a drain electrode d. The circuit operates as follows in a first, a second and a third intervals: in the first interval positive voltage is applied to a gate electrode g and by closing the switch S1 the opposite ends of the capacitive element 13 is short-circuited; the application of the positive voltage is interrupted and the switch S1 is opened; in the second interval the short-circuiting of the capacitive element 13 is opened by closing the switch S2 reference voltage Va is applied to opposite ends of the capacitive element 13; in the third interval where the switch S2 is opened, incident light quantity into the TFT 11 is detected based on a voltage change across the opposite ends of the capacitive element 13. COPYRIGHT: (C)2010,JPO&INPIT