US Patent Number
An inexpensive electrical sensor of plane coordinates employs juxtaposed sheets of conducting material having electrical equipotential lines extending across each sheet and arranged normal to each other. A probe upon touching each sheet at a selected intersection of the equipotential lines causes separate signals to be applied to one or more conventional information-indicating units.
University of Kentucky Research Foundation, Lexington, Ky.
Hurst, George S. and Parks, James E., "Electrical Sensor of Plane Coordinates" (1972). Physics and Astronomy Faculty Patents. 8.