DEFECT COMPENSATING CIRCUIT FOR SOLID-STATE IMAGE PICKUP ELEMENT

摘要

PURPOSE:To improve the reliability at the operation by providing the 3rd sample-and-hold circuit to the 2nd sample-and-hold circuit receiving a picture element signal to compensate a defect picture element via an impedance conversion circuit and giving a sampling signal representing the location of defect picture element to the 3rd sample-and-hold circuit. CONSTITUTION:An output signal from a solid-state image pickup element is inputted respectively to the 1st and 2nd sample-and-hold circuits SH1, SH2 from an input terminal IN and the sample-and-hold circuit SH1 uses a pulse phiS sampling all picture elements to hold the signal. A conventional picture output from a normal picture element is outputted as a signal of the 1st sample- and-hold circuit SH1. As to a defect picture element position, the picture element is subject to sample and hold at the 3rd sample-and-hold circuit SH3 by using a pulse phiS0. The sampling pulse phiS of the sample-and-hold circuit SH1 is held in the pause state, the output of the sample-and-hold circuit SH1 saves the signal through an emitter follower EF and the output of the sample-and-hold circuit SH3 is made effective.