Piezoelectric ultrasonic transducer with resonator laminate
First Claim
1. 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.
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Abstract
An ultrasonic transducer comprises a composite vibrator, which comprises a bimorph vibrator and a resin made additional resonator of a frustum of a cone provided at the central portion of the bimorph vibrator. The composite vibrator gives rise to the first resonance by a piston vibration mode at the lower frequency region and the second resonance by a bending vibration mode at the higher frequency region as compared with the central frequency. The composite vibrator is fixed to an insulating base through a ring shaped elastic member, whereby a resonance characteristic by virtue of a piston vibration mode is enhanced. Preferably a protrusion of the diameter slightly smaller than the nodal circle by virtue of a bending vibration mode is formed on the transducing surface of the resin made additional resonator of a frustum of a cone. The protrusion serves to reduce the quality factor of the second resonance by virtue of a bending vibration mode.
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Citations
11 Claims
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1. An ultrasonic transducer, comprising:
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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. - View Dependent Claims (2, 3, 4, 5)
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6. An ultrasonic transducer, comprising:
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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, said protrusion taking the form of a cylindrical post and having a diameter substantially equal to the diameter of the fundamental nodal line circle of said second resonance region of said composite vibrator; an insulating base on which said composite vibrator is mounted; and an elastic member interposed between said bimorph vibrator and said insulating base. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification