Patent ID: 6942619

Claim:
An ultrasound radiation device comprising: a piezoelectric substrate having upper- and lower end surfaces; an interdigital arrangement of two comb-shaped electrodes formed on said upper end surface of said piezoelectric substrate; a counter electrode formed on said lower end surface of said piezoelectric substrate and in contact with a material through the lower end surface of said counter electrode; an interdigital transducer formed on said upper end surface of said piezoelectric substrate; and an amplifier between one of said two comb-shaped electrodes and said interdigital transducer, said one of said two comb-shaped electrodes and said counter electrode receiving an electric signal, and radiating a longitudinal wave, composed of the main lobe and grating lobes, into said material, as well as exciting a Lamb wave in said piezoelectric substrate, said interdigital transducer detecting said Lamb wave as a delayed electric signal, said amplifier amplifying said delayed electric signal, and supplying said one of said two comb-shaped electrodes with an amplified electric signal as an input electric signal.