Patent ID: 6498604
Filing Date: 2002-12-24
Classification: G06F

Abstract:
An input device for positioning a cursor on a computer screen, the device comprising:a ball adapted to move on a substrate; optical detection means for detecting angular rotation of the ball in two dimensions perpendicular to each other, and transforming the angular rotation of the ball in two perpendicular dimensions into electrical signals; wherein said optical detection means comprises a first set of detectors adapted to detect an angular rotation in a first of the two perpendicular dimensions, said first set comprising at least two detectors, a second set of detectors adapted to detect an angular rotation in a second of the two perpendicular dimensions, said second set comprising at least two detectors, and at least one source of substantially coherent electromagnetic radiation communicating with the first and second sets of detectors through a system of lenses, the system of lenses being common to the first and second sets of detectors and the at least one source of coherent electromagnetic radiation, such that light to both the first and second sets of detectors passes through the common system of lenses, and such that light both from the source and to the detectors passes through the common system of lenses.