Abstract: The piezoelectric signal generator (10;30) includes at least one piezoelectric element (12;20) connected with an emitter (14;35) which is capable of generating, from a current (C) produced by actuation of the piezoelectric element, an electromagnetic signal (S) capable of being wirelessly received by a receiver (16;36) removed from the signal generator (10;30), the piezoelectric element (20;31) comprises a piezoceramic layer (241) attached to an electrically conducting carrier stratum (242); the piezoceramic layer adheres to the carrier stratum and both are held by a positioning layer (23) which has a thickness (TP), and both are capable of a reversible deformation, predetermined by and limited to the thickness (TP) of the positioning layer (23); further, the piezoelectric element (20;31) comprises a gap layer (26) for buffering the reversible deformation of the carrier stratum (242) with the adhering piezoceramic layer (241); the gap (29) has a thickness (TG) such that TG?TP.

Abstract: A monolithic piezoelectric key structure having a piezoelectric layer adherently connected between two conductive areas. The piezoelectric layer is applied as a fluid on the base conductive area and transformed into a coherent solid adhering to the base conductive area. The other conductive area is adherently formed on the piezoelectric layer. The monolithic structure is polarized.