Logarithmic-Converting CMOS Area Image Sensors with an FPN Cancel Circuit

Abstract

Logarithmic-converting CMOS area image sensors with an FPN cancel circuit, fabricated using a conventional CMOS process, have been developed. The sensors have 540 (H) × 148 (V) pixels, each with a logarithmic-converting circuit and a simple FPN cancel circuit. Their cells are 7 μm (H) × 21 μm (V). They output a signal with a strength logarithmically proportional to the integrated amount of photo current generated by incident light. They can therefore capture bright and dark objects at the same time without using a frame memory. This sensor should thus find application in consumer (digital still cameras, digital video cameras, and so on) and industrial products.