APPARAT OG FREMGANGSMAADE TIL BESTEMMELSE AF ET KONTAKTPUNKTS KOORDINATER PAA EN RESISTIV OVERFLADE

摘要

A method and apparatus for determining the coordinates of a point of contact of an object on a semianalog sensitive surface. The coordinates are of a zone of contact of a conductive object such as a finger on a sensitive surface. The surface consists of an insulating support having a grid formed by two terminals between which a certain number of emitting resistant strips are connected in parallel and detecting conductive strips, placed between the resistant strips. The conductive strips are connected separately to a selection switch making it possible successively to sample the voltage of each detecting strip. The operation is performed in two phases by polarizing the two terminals of the grid, first in phase, then in opposite phase, and in each phase of the process the averages are taken of a certain number of synchronous samples which make it possible to determine the two coordinates.