Piezoelectric signal generator for entry system

摘要

The piezoelectric subassembly is formed by an array (12) of discrete elements (20) secured to a phosphor bronze substrate (22). A respective lead (28) extends from each of five lead zirconate titanate elements (20) to a respective terminal (30). Terminal strips (32) supply alternating current to the electroluminescent panel (14) which is less than one mm. thick and quite flexible. - A respective identifying indicium for each crystal (20) is provided on a decal (34) of plastics material disposed between the panel (14) and the transparent cover (16). The cover is sufficiently flexible to transmit a finger-generated force of 0.25-1.0 kilogram from the cover to the crystals. The displacement of the cover is not more than 0.025 mm.