Patent ID: 6317389
Filing Date: 2001-11-13
Classification: B06B

Abstract:
An ultrasound-signal radiating device comprising:a piezoelectric substrate having two end surfaces;a first input interdigital transducer;a second input interdigital transducer;an output interdigital transducer, all said first input-, said second input-, and said output interdigital transducers being formed on one end surface of said piezoelectric substrate;a cap mounted on a surface part of the other end surface of said piezoelectric substrate, said surface part corresponding to a surface part, including said first input- and said output interdigital transducers, of said one end surface of said piezoelectric substrate;an amplifier; anda modulator with an input terminal,said first input interdigital transducer receiving an input electric signal, exciting a non-leaky elastic wave in said piezoelectric substrate,said output interdigital transducer detecting said non-leaky elastic wave as a delayed electric signal,said amplifier amplifying said delayed electric signal and feeding a signal part, as said input electric signal, of an amplified electric signal, back to said first input interdigital transducer, again,said modulator receiving not only an input message-signal through said input terminal but also a remaining signal part, as a carrier signal, of said amplified electric signal, modulating an amplitude of said carrier signal according to said input message-signal, and generating an AM signal,said second input interdigital transducer receiving said AM signal, exciting a leaky elastic wave in said piezoelectric substrate, and radiating said leaky elastic wave in the form of a longitudinal wave into a liquid through a remaining surface part of said other end surface of said piezoelectric substrate.