Keyboard with flexible top foil and conducting discs - is separated from matrix of orthogonal conductors by compressible fluid

摘要

The keyboard, for pocket calculators etc., consists of a matrix of orthogonal mutually insulated conducting paths on the top surface of an insulating plate (13). The paths (15) in one set of parallel conductors are broken to allow the continuous paths (14) of the orthogonal set of conductors to pass straight through. A flexible foil (18) has conducting discs (19) on its underside and is separated from the path matrix by a compressible fluid (20). Depressing the foil at given points connects the paths together.