Suppressing radiation charges from reaching dark signal sensor

摘要

An image sensor and method is provided to improve the measurement of a dark signal reference while substantially suppressing radiation charges that enter an active area of the image sensor from reaching a shielded dark signal detector. In one implementation, dark signal detector is shielded and separated from the active area to substantially reduce the radiation charges that reach the dark signal detector. In another implementation, the image sensor includes a radiation guard that is disposed between the active area and the shielded detector. When radiation or light is permitted to enter the active area, the guard when adequately biased attracts and collects radiated charges that may otherwise travel beyond the active area to reach the shielded detector and contaminate a measurement for the dark signal reference.