Ultrasonic probe

• US 5,465,725 A
• Filed: 01/30/1995
• Issued: 11/14/1995
• Est. Priority Date: 06/15/1993
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett Packard Company (HP Inc.)
• Inventors: Seyed-Bolorforosh, Mir S.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US08/381,607
• Time in Patent Office: 288 Days
• Field of Search: 128/660.01, 128/661.01, 128/662.03, 310/334, 310/359, 310/365, 310/366, 359/311, 73/625
• US Class Current: 600/459
• CPC Class Codes: B06B 1/0629 Square array
• CPC Class Codes: B06B 2201/20 Application to multi-element transducer
• CPC Class Codes: G10K 11/02 Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators

Abstract

A tunable ultrasonic probe of the that provides efficient electrical coupling of probe control lines to imaging system components and further provides for variable control over size of an effective acoustic aperture of the probe. The ultrasonic probe includes a body of a piezoelectric material that has a first surface and an opposing surface. A first set of electrodes is coupled with the first surface of the body. A second set of electrodes is also coupled with the first surface of the body and arranged so that each electrode of the second set substantially overlaps at least a respective one electrode of the first set. A third set of electrodes is coupled with the opposing surface of the body. At least one bias voltage source is coupled with the electrodes for substantially polarizing ceramic material within selected regions of the body. Switches are coupled with the first and second set of electrodes for changing an acoustic aperture of the probe by varying size of the selected polarized regions. The polarization of the selected regions of the piezoelectric material is controlled so as to variably tune a frequency of the beam of acoustic signals while controlling the acoustic aperture of the probe.

Claims

1. An ultrasonic probe for coupling a beam of acoustic signals between the probe and a medium, the probe comprising:

a body of piezoelectric material, the body having a first surface and an opposing surface;

a first electrode coupled with the first surface of the body;

a second electrode coupled with the first surface of the body and arranged so that the second electrode substantially overlaps the first electrode; and

a third electrode coupled with the opposing surface of the body.

2. A probe as in claim 1 further comprising an insulator layer disposed between the first electrode and the second electrode.

3. A probe as in claim 1 further comprising a switch for selectively interconnecting the first electrode and the second electrode.

4. A probe as in claim 1 further comprising:

a first set of electrodes coupled with the first surface of the body;

a second set of electrodes coupled with the first surface of the body and arranged so that each electrode of the second set substantially overlaps at least a respective one electrode of the first set.

5. A probe as in claim 4 wherein the piezoelectric material includes a relaxor ferroelectric ceramic material having a variable polarization.

6. A probe as in claim 5 wherein at least one bias voltage source is coupled with the electrodes for substantially polarizing ceramic material within selected regions of the body.

7. A probe as in claim 6 further comprising switches coupled with the first and second set of electrodes for changing an acoustic aperture of the probe by varying size of the selected polarized regions.

8. A probe as in claim 7 further comprising a means for controlling the switches so as to change the acoustic aperture of the probe in response to transmission of the acoustic beam from the probe and reception of the acoustic beam by the probe.

9. A probe as in claim 7 further comprising means for controlling the polarization of the selected regions of the piezoelectric material so as to variably tune a frequency of the beam of acoustic signals while controlling the acoustic aperture of the probe.

10. A probe as in claim 6 further comprising switches coupled with the first and second set of electrodes for apodizing the acoustic beam by varying size of the selected polarized regions.

11. A probe as in claim 5 wherein:

the body has a central axis;

each member of the first and second sets of electrodes extend radially outward from the central axis of the body.

12. An ultrasonic probe as in claim 5 wherein each member of the first and second set of electrodes is substantially sector shaped.

13. An ultrasonic probe as in claim 5 further comprising a third set of electrodes coupled with the opposing surface of the body and concentrically arranged about the central axis of the body.

14. An ultrasonic probe as in claim 5 further comprising a third set of electrodes coupled with the opposing surface of the body wherein each member of the third set of electrodes is substantially semicircular.

15. An ultrasonic probe as in claim 1 wherein:

the third electrode has a longitudinal dimension extending along a longitudinal dimension of the probe;

the first and second electrodes each have a respective longitudinal dimension arranged substantially perpendicular to that of the third electrode.

16. An ultrasonic probe as in claim 1 wherein:

the third electrode has a longitudinal dimension extending along a longitudinal dimension of the probe;

the first and second electrodes each have a respective longitudinal dimension arranged substantially parallel to that of the third electrode.

17. An ultrasonic probe for coupling a beam of acoustic signals between the probe and a medium, the probe comprising:

a body of piezoelectric material, the body having a first surface and an opposing surface;

a first pair of adjacent electrodes spaced apart to provide a separation therebetween, and coupled with the first surface of the body;

a second electrode coupled with the first surface of the body and arranged so that the second electrode substantially overlaps the separation between the first pair spaced apart electrodes; and

a third electrode coupled with the opposing surface of the body.

18. A probe as in claim 17 further comprising:

a first set of spaced apart electrodes coupled with the first surface of the body, members of the first set of electrodes being spaced apart from one another to provide a respective separation between each pair of adjacent members of the first set; and

A second set of electrodes coupled proximate with the first surface of the body and arranged so that a respective member of the second set substantially overlaps the respective separation between each pair of adjacent members of the first set.

19. A probe as in claim 17 wherein:

the piezoelectric material includes a relaxor ferroelectric ceramic material having a variable polarization; and

the probe further comprises;

at least one bias voltage source coupled with the electrodes for substantially polarizing ceramic material within selected regions of the body; and

switches coupled with the first and second set of electrodes for changing an acoustic aperture of the probe by varying size of the selected polarized regions.

20. A probe as in claim 17 wherein:

the body has a central axis;

each member of the first and second sets of electrodes are substantially sector shaped and extend radially outward from the central axis of the body; and

the probe further comprises a third set of substantially semicircular electrodes coupled with the opposing surface of the body and concentrically arranged about the central axis of the body.