Piezoelectric ultrasonic transducer with resonator laminate

An ultrasonic transducer, comprising:

• a composite vibrator including a piezoelectric bimorph vibrator and a resin resonator mounted on said bimorph vibrator, said composite vibrator having a first resonance region located in a first frequency range in which said composite vibrator vibrates in a piston vibration mode and a second resonance region located in a second frequency range, higher than said first frequency range, in which said composite vibrator vibrates in a bending vibration mode, said resin and resonator including a protrusion formed on the transducing surface thereof;
• an insulating base on which said composite vibrator is mounted, said insulating base including a protruding portion;
• and
• an elastic member interposed between said bimorph vibrator and said insulating base, said elastic member being formed in a ring shape and having a thickness larger than the height of said protruding portion of said insulating base, said protruding portion of said insulating base having an outer diameter slightly smaller than the inner diameter of said ring-shaped elastic member, said ring-shaped elastic member being fitted on said protruding portion of said insulating base such that said elastic member extends above said protruding portion and said bimorph vibrator of said composite vibrator is mounted on said elastic member.