Field-Coupled Pointing Device

U.S. Patent number: 4,564,835
Filed: Dec. 13, 1982
Issued: Jan. 14, 1986
Inventor: Satish K. Dhawan

Seeking to improve on both electromechanical and optical mice, inventor Satish Dhawan designed a mouse that measures movement by detecting changes in an electrical field generated between the mouse and special mouse tablet. Shown in this drawing, the mouse tablet would have a "repetitive, regular pattern of spaced-apart conductive pixels." According to the patent, the mouse would contain "coupling elements which electrically field couple with the pixels," "means for establishing an electrical field from the coupling elements," and a "means for detecting changes in that field."

Dhawan believed mice using this design would be cheaper to manufacture and offer more precise cursor movement than electromechanical mice. The design would also allow drawings or other papers (like building plans or mechanical diagrams) to be placed between the mouse and mouse surface. Lastly, Dhawan thought the design would be more tolerant of a dirty mouse surface than optical mice of the time.

Image taken from U.S. Patent 4,564,835 - Digitized by Google