Analysis of optical writing mode in solid-state imaging devices with inherent MNOS memory

A model for optical writing in solid-state imaging devices with an inherent MNOS memory is presented. It is shown that writing under low light levels is highly enhanced by the use of a proper bias-charge (fat-zero). The optimum operating condition under which wide dynamic range can be realised without degradation of the writing is also derived. Experimental results from test elements support these theoretical predictions. Finally, erase characteristics of the MNOS analog memory are presented.