A CMOS motion detector system for pointing devices

A motion detector system uses an array of 93 photodiodes integrated along with processing circuits to detect the motion of a printed random pattern on a ball used in a pointing device application. It is based on the detection and tracking of spot edges passing over a matrix of pixels during the period between two light pulses. Motion in x and y directions is estimated by aggregating local information about moving edges over the photosensitive pixels. The 4.4/spl times/4.3 mm/sup 2/ chip detects the ball motion from 0 to 11.8 in/s with a resolution higher than 800 dpi over a 100-2000 mW/m/sup 2/ light-intensity range.