Ultrasonic probe system
First Claim
1. An ultrasonic probe system comprising:
- probe head means for transmitting or receiving ultrasonic waves having different frequencies, said probe head means comprising,a stacked piezoelectric element including a plurality of piezoelectric layers for transmitting or receiving ultrasonic waves having different frequencies stacked on each other in a direction of thickness, a plurality of first electrodes bonded to opposed end faces of said plurality of piezoelectric layers in a stacking direction, and at least one second electrode bonded to an interface between said plurality of piezoelectric layers,ultrasonic focusing means bonded to an upper surface of said piezoelectric layers and having a convex surface directed outward, andwiring means connected to said first electrode of said piezoelectric layer; and
control means for controlling said ultrasonic frequencies by controlling polarization directions of said plurality of piezoelectric layers.
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Accused Products
Abstract
An ultrasonic probe system is disclosed, which is designed to allow connection of a DC power supply capable of applying a voltage higher than the coercive electric field of each of a plurality of piezoelectric layers thereto, and includes a polarization turn over circuit means for, when the DC power supply is driven, turning over the polarity of the DC power supply so as to direct electric fields of every two adjacent layers constituting the piezoelectric layers in substantially opposite directions or electric fields of all the layers in the same direction. When the polarization turn over circuit means turns over the polarity of a voltage to be applied to direct electric fields of every two adjacent layers of the piezoelectric layers in substantially opposite directions or electric fields of all the layers in the same direction, the polarization turn over circuit means performs control to apply the voltage during a blanking time of an operating time of the system, thereby performing conversion of a resonance frequency, and selectively generating ultrasonic waves having a plurality of different frequencies.
196 Citations
16 Claims
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1. An ultrasonic probe system comprising:
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probe head means for transmitting or receiving ultrasonic waves having different frequencies, said probe head means comprising, a stacked piezoelectric element including a plurality of piezoelectric layers for transmitting or receiving ultrasonic waves having different frequencies stacked on each other in a direction of thickness, a plurality of first electrodes bonded to opposed end faces of said plurality of piezoelectric layers in a stacking direction, and at least one second electrode bonded to an interface between said plurality of piezoelectric layers, ultrasonic focusing means bonded to an upper surface of said piezoelectric layers and having a convex surface directed outward, and wiring means connected to said first electrode of said piezoelectric layer; and control means for controlling said ultrasonic frequencies by controlling polarization directions of said plurality of piezoelectric layers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An ultrasonic probe system for transmitting or receiving ultrasonic waves having different frequencies, comprising:
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a stacked piezoelectric element comprising a plurality of piezoelectric layers stacked on each other such that polarization directions of every two adjacent layers are opposite to each other or polarization directions of all the layers coincide with each other, first electrodes respectively bonded to said piezoelectric layers and located at opposed ends in a stacking direction, and a second electrode being bonded to a portion between said two adjacent piezoelectric layers, and a DC power supply for supplying a voltage to each of said piezoelectric layers, the voltage being higher than a coercive electric field of each of said piezoelectric layers; wherein said DC power supply is capable of applying a voltage higher than a coercive electric field of each of said plurality of piezoelectric layers to each of every other piezoelectric layer connected thereto, and said system further comprises polarization turn over means capable of turning over a plurality of the voltage applied by said DC power supply.
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16. The ultrasonic probe system for transmitting or receiving ultrasonic waves having different frequencies, comprising:
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a plurality of piezoelectric layers including a plurality of piezoelectric members having predetermined polarization directions and the same thickness stacked one upon the other; a DC power supply for applying a voltage to each of said piezoelectric layers, the voltage being higher than a coercive electric field of each of said piezoelectric layers; and polarization turn over circuit means for changing the direction of electric field of all the layers by turning over the polarity of the voltage of said DC power supply so as to direct electric fields of every two adjacent layers constituting said piezoelectric layers in substantially opposite directions or electric fields of all the layers in the same direction thereby generating an ultrasonic wave having a frequency selected from a plurality of different frequencies.
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Specification