Composite top membrane for flat panel switch arrays

Abstract

A composite top membrane designed for use with membrane-type switch arrays which is substantially smooth and ripple free. The composite membrane comprises: (1) a layer of plastic foam which is coated on each side with a pressure sensitive adhesive; (2) a decorative cover layer formed from plastic and having graphic indicia on one or both surfaces and which is adhesively affixed to one side of the aforementioned layer of plastic foam; and (3) a sheet of plastic having a significant memory property having its first surface adhesively affixed to the other side of the foam layer and a pattern of conductive metallization on its second surface. The layer of foam material provides a flat, resilient interface between the decorative cover layer and the relatively convoluted surface of the flexible printed circuit top membrane. As such, the decorative layer remains flat and free from optical irregularities which would detract from its aesthetic impression.

Dependencies are inferred from the claim text.