CMOS ACTIVE PIXEL SENSOR PROVIDED WITH INTRA-PIXEL LOCAL EXPOSURE CONTROL FUNCTION

摘要

PROBLEM TO BE SOLVED: To provide the image pickup performance of a high dynamic range and high sensitivity by providing variable length exposure time with duration based on the size of optical signals and indicating the intensity of incident light by time dependent signals. ;SOLUTION: An image pickup device 22 is constituted of the array 24 of pixels 25 and the pixel 25 becomes an optical sensor for generating the optical signals corresponding to the intensity of the incident light. As the function of the variable length exposure time of the optical sensor, the time dependent signals are formed by a converter. The variable length exposure time is provided with a duration length based on mathematic relation with the size of the optical signals and thus, the time dependent signals indicate the intensity of the incident light. The optical signals are analog signals and the converter receives analog optical signals and generate the time dependent signals by a digital form. Also, the converter is provided with a circuit for deciding the duration length of the variable length exposure time based on the detection of a pre-selected voltage drop generated by the incident light and a comparator for comparing integration signals with reference signals.;COPYRIGHT: (C)2000,JPO