Ultrasonic transducer for three dimensional imaging

DETAILED DESCRIPTION The present invention provides a probe having a reduced number of beam forming channels and signal cables, while still providing high resolution acoustic imaging.
Ultrasonic probes of the prior art included an array of a large number of separate piezoelectric ceramic transducer elements, a large number of signal cables, and a large number of beam forming channels to provide high resolution acoustic imaging.
In contrast to the piezoelectric ceramic transducer elements of the prior art which each have a fixed polarization, the present invention uses a probe body including relaxor ferroelectric ceramic material which becomes polarized and therefore electromechanically active only under influence of an applied bias voltage.
Instead of using a large number piezoelectric ceramic elements as in the prior art, the present invention provides high resolution acoustic imaging by using column regions of the probe body which are electrically selected by substantially polarizing the regions only when a bias voltage is applied to the regions by a novel electrode arrangement.
In accordance with some teachings of the prior art, to provide a high acoustic imaging resolution corresponding to a large number, N.
sup.
2, of acoustic signal channels, requires an array of a large number, N.
sup.
2, of separate piezoelectric ceramic transducer elements, a large number, N.
sup.
2, of signal cables, and a large number, N.
sup.
2, of beam forming channels.
Therefore, according to some teachings of the prior art, high acoustic imaging resolution of a 128 by 128 array of piezoelectric ceramic transducer elements requires 16,384 signal cables and a set of 16,384 beam forming channels.
In contrast, the present invention provides high resolution acoustic imaging equivalent to that which corresponds to a large number, N.
sup.
2, of separate piezoelectric ceramic elements of the prior art, while using a lesser number, N, of signal cables, and a lesser number, N, of beam forming channels.
For example, the present invention provides high resolution acoustic imaging equivalent to that which corresponds to a 128 by 128 two dimensional array of piezoelectric ceramic transducer elements of the prior art, while using a lesser number of signal cables (128 cables), and a lesser number of beam forming channels (128 channels)