Patent US 5,349,371

An electro-optical mouse includes two light sources to respectively project light onto a grid of lines on a reflective surface; two cylindrical lenses at right angles to each other to respectively amplify the X and Y line crossings; two detectors to respectively receive the output light signals from the two cylindrical lenses via two reflectors and, generate electrical signals according to the sensed changes in contrast ratio, in order to accurately control the movement of a cursor on the visual display of a computer.