TOUCH-SENSITIVE SWITCH EMPLOYING ELECTRET FOIL

摘要

A keyboard switching arrangement that is mechanically simple, reliable, and which can be fabricated with an overall thickness of less than 1/4 inch, includes a plurality of independent conductive elements aligned with holes in a protective front cover. A single sheet of a metallized foil electret is interposed between the cover and the conductive members. The metal layer of the foil forms a capacitive transducer with each backplate section. Each switch is operated by touching the foil electret through one of the cover holes. The resulting displacement generates an electric output signal which is utilized for actuating an associated switching element or the like.