Patent ID: 7193617

Claim:
An acoustic contact detecting device comprising (a) a substrate having a top surface and a bottom surface; (b) an acoustic wave transducer for coupling with a first wave representative of a bulk wave being propagated between the top surface and the bottom surface through said substrate along an axis crossing said top surface, said acoustic wave transducer comprising a piezoelectric substrate and a piezoelectric vibrator having electrode sections disposed on both surfaces of said piezo electric substrate; (c) a planar wiring for supplying said acoustic wave transducer with electric power, said planar wiring comprising a first wiring section capable of contacting with one of said electrode sections of said piezoelectric vibrator by way of line or face contact and a second wiring section spaced and insulated from said first wiring section; (d) a connecting device for connecting said acoustic wave transducer with the planar wiring, said connecting device being formed in a form capable of connecting the other electrode section of said piezoelectric vibrator with said second wiring section; (e) a diffractive acoustic wave mode coupler having a mode of converted wave having high energy on said top surface and functioning for coupling a second wave being propagated along an axis parallel to said top surface with said first wave; and (f) a means for detecting a perturbation in the energy of said second wave.