A photodiode cell for applications to position and motion estimation sensors

An optical cell has been designed and fabricated using standard digital 1.6 μm CMOS technology. It has been designed for applications to sensors where the image acquisition time of fast moving objects or documents is of primary importance. The cell contains a photodiode working in storage mode and a shielded MOS capacitor acting as analog frame buffer. A chip prototype containing 64 linear arrays of 64 cells whose size is 36×36 μm² has been tested and measurements have proved the functionality down to microsecond-range of exposure times. By virtue of the proposed read-out technique, the sensor architecture provides simultaneous image acquisition of irregular moving objects allowing precise detection of position and motion