Experimental autofocus system for lens shutter cameras

Research results on a mainly digitally working autofocus system using an optical module without moving parts are presented. The chip was fabricated in a well-established NMOS technology. It contains two linear arrays of 52 photodiodes each and parts of the signal processing necessary to evaluate the appropriate distance zone. Fifteen zones can be resolved between infinity and 1 m. Minimum scene brightness is about 1...4 cd/m/SUP 2/ for daylight type illumination. The total measuring time comprising integration of optically generated charge carriers and signal processing does not exceed 25 ms. These features make the system attractive for low-cost lens shutter cameras.