Capacitive touch entry apparatus having high degree of personal safety

摘要

A capacitive touch entry structure utilizes an array of at least one capacitive touch sensor fabricated upon a double-sided printed circuit board adhesively mounted upon a surface of a transparent insulative substrate. The substrate has sufficient thickness to safely insulate user personnel, contacting the substrate surface furthest from an electrode of the capacitive touch sensor, from electrical potentials present adjacent to the panel surface upon which the capacitive touch sensor is fastened. Touch sensor circuitry and interconnections may be advantageously fabricated directly upon the pair of conductive planes, sandwiching an insulative layer therebetween, to form the printed circuit portion of the structure. A conductive guard may also be disposed adjacent to the substrate to shield at least the lead portions of the touch sensors from capacitive effects.