CMOS photodetector with built-in light adaptation mechanism

This paper reports research results on a new class of silicon hotodetectors with built-in light adaptation mechanisms. Previously used devices feature a limited dynamic range which is much smaller than a range of light intensity present in our environment. Intelligent vision systems functioning similarly to human vision systems require new photodetectors with abilities not only to cover wider dynamic range, but also able to accomplish background adaptation and dark adaptation mechanisms similar to those existing in human retina. The proposed class of devices uses the same silicon structure operating in two or more operating modes of different sensitivity, with light-controllable switching between different modes. The measurements conducted on CMOS photodetectors fabricated in the 3 μm CMOS technology show that the new photodetectors have a dynamic range increased by at least two orders of magnitude and feature limited power consumption, which is especially attractive for large area transducer systems.