Transducer surface mapping

• US 7,535,794 B2
• Filed: 01/29/2007
• Issued: 05/19/2009
• Est. Priority Date: 08/01/2006
• Status: Active Grant

• Current Assignee: InSightec Ltd.
• Original Assignee: InSightec Ltd.
• Inventors: Vitek, Shuki, Prus, Oleg
• Primary Examiner(s): PIHULIC, DANIEL T
• Application Number:
  US11/668,321
• Publication Number:
  US 20080031090A1
• Time in Patent Office: 841 Days
• Field of Search: 367/13, 367/103, 367/105, 73/10.1, 342/165
• US Class Current: 367/13
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205
• CPC Class Codes: G10K 11/346 using phase variation

Abstract

Method for adjusting the output of a phased array ultrasonic transducer using surface mapping. The transducer surface is mapped using a sensor, such as a hydrophone, to determine the actual location of each transducer element relative to the expected location of each transducer element. Mapping can be performed by measuring a distance between a hydrophone and each transducer element. At least one of the hydrophone and the transducer are moveable relative to each other to map the transducer surface. A determination is made whether the actual location of a transducer element differs from the expected location. Drive signals of certain transducer elements having actual locations that differ from expected locations are adjusted to control the output of the transducer.

Claims

1. A method of mapping a surface of a multi-element transducer comprising:

measuring a time of flight of a pulse emitted from each transducer element and detected by a sensor;

determining a distance between each transducer element and the sensor based on the time of flight; and

determining the actual location of each transducer element based on the determined distance.

2. The method of claim 1, determining the distance further comprising:

measuring a time of flight of a first pulse emitted by a transducer element and detected by a sensor;

moving the sensor from a first location to a second location; and

measuring the time of flight of a second pulse emitted by the transducer element and detected by the sensor at the second location.

3. The method of claim 1, measuring the time of flight further comprising

measuring a time of flight of a pulse emitted by a transducer element and detected by a hydrophone.

4. The method of claim 3, determining the distance further comprising

determining a distance between each transducer element and one or more hydrophones of a hydrophone array.

5. The method of claim 4, further comprising:

activating a first hydrophone of the hydrophone array;

measuring a first time of flight of a pulse emitted by a transducer element and detected by the first hydrophone; and

determining a first distance between the transducer element and the first hydrophone based on the measured first time of flight, the determined first distance being used to determine the actual location of the transducer element.

6. The method of claim 5, further comprising

activating a second hydrophone of the hydrophone array;

measuring a second time of flight of a pulse emitted by the transducer element and detected by the second hydrophone; and

determining a second distance between the transducer element and the second hydrophone based on the measured second time of flight, the determined first and second distances being used to determine the actual location of the transducer element.

7. The method of claim 6, wherein the first and second hydrophones are active at the same time.

8. The method of claim 6, further comprising deactivating the first hydrophone, wherein the first and second hydrophones are sequentially activated so that the first hydrophone is not active when the second hydrophone is active.

9. The method of claim 1, mapping the transducer surface being performed by moving a sensor relative to a transducer, or by moving the transducer relative to a fixed sensor.

10. A method of controlling an output of a multi-element ultrasonic transducer, comprising:

mapping a surface of the transducer by determining an actual location of each transducer element of the transducer; and

adjusting a drive signal of one or more transducer elements based on a comparison of the actual location and the expected location of each transducer, thereby adjusting the output of the transducer.

11. The method of claim 10, a focus or a shape of a beam generated by the transducer being adjusted.

12. The method of claim 10, a drive signal of a transducer element being adjusted using the actual location of the transducer element if the actual location of the transducer element deviates from an expected location of the transducer element by a predetermined amount.

13. The method of claim 10, drive signals of certain transducer elements being adjusted based on respective actual locations of the certain transducer elements, and drive signals of other transducer elements being based on respective expected locations of the other transducer elements.

14. The method of claim 10, the expected location of a transducer element being based on a shape or design of a surface of the phased array ultrasonic transducer.

15. The method of claim 10, mapping the surface further comprising:

measuring a time of flight of a pulse emitted from each transducer element and detected by a sensor;

determining a distance between each transducer element and the sensor based on the time of flight; and

determining the actual location of each transducer element based on the determined distance.

16. The method of claim 15, determining the distance further comprising:

measuring a time of flight of a first pulse emitted by a transducer element and detected by a sensor;

moving the transducer from a first location to a second location; and

measuring the time of flight of a second pulse emitted by the transducer element and detected by the sensor at the second location.

17. The method of claim 15, determining the distance further comprising:

measuring a time of flight of a first pulse emitted by a transducer element and detected by a sensor;

moving the sensor from a first location to a second location; and

measuring the time of flight of a second pulse emitted by the transducer element and detected by the sensor at the second location.

18. The method of claim 15, measuring the time of flight further comprising

measuring a time of flight of a pulse emitted by a transducer element and detected by a hydrophone.

19. The method of claim 18, determining the distance further comprising

determining a distance between each transducer element and one or more hydrophones of a hydrophone array.

20. The method of claim 19, further comprising:

activating a first hydrophone of the hydrophone array;

measuring a first time of flight of a pulse emitted by a transducer element and detected by the first hydrophone; and

determining a first distance between the transducer element and the first hydrophone based on the measured first time of flight, the determined first distance being used to determine the actual location of the transducer element;

activating a second hydrophone of the hydrophone array;

measuring a second time of flight of a pulse emitted by the transducer element and detected by the second hydrophone; and

determining a second distance between the transducer element and the second hydrophone based on the measured second time of flight, the determined first and second distances being used to determine the actual location of the transducer element.

21. The method of claim 20, wherein the first and second hydrophones are active at the same time.

22. The method of claim 20, further comprising deactivating the first hydrophone, wherein the first and second hydrophones are sequentially activated so that the first hydrophone is not active when the second hydrophone is active.

23. The method of claim 10, mapping the transducer surface being performed by moving a sensor relative to a transducer, or by moving the transducer relative to a fixed sensor.

24. The method of claim 10, further comprising

generating an initial file having the expected location of each transducer element based on a design of the transducer;

determining whether the actual location of each transducer element deviates from expected location the transducer element based on the initial file;

generating an updated file having the actual locations of transducer elements that deviate from the expected locations; and

adjusting a drive signal of a transducer element based on the updated file.

25. The method of claim 24,

generating the initial file comprising generating an initial file having expected coordinates of each transducer element, and

generating the updated file comprising generating an updated file including

actual coordinates of certain transducer elements having an actual location that deviates from the expected location, and

expected coordinates of other transducer elements.

26. A method of controlling an output of a multi-element ultrasonic transducer, comprising:

generating an initial file having an expected location of each transducer element of the transducer based on a shape or design of a surface of the transducer;

mapping the surface of the transducer by determining, for each transducer element, an actual location of the transducer element relative to an expected location of the transducer element;

comparing the actual locations of the transducer element to respective expected locations of the transducer elements;

generating an updated file including actual locations of transducer elements having an actual location that deviates from the expected location; and

adjusting drive signals of transducer elements using the updated file, thereby adjusting the output of the transducer.

27. The method of claim 26, generating the initial file comprising generating an initial file having expected (x,y,z) coordinates of each transducer element, and generating the updated file comprising generating an updated file including actual (x,y,z) coordinates of selected transducer elements having actual locations that deviate from the expected locations of the respective selected transducer elements, and expected (x,y,z) coordinates of other transducer elements.

28. The method of claim 26, a focus or a shape of a beam generated by the transducer being adjusted.

29. The method of claim 26, drive signals of certain transducer elements being adjusted based on respective actual locations of the certain transducer elements, and drive signals of other transducer elements being based on respective expected locations of the other transducer elements.

30. The method of claim 26, mapping the surface of the phased array ultrasonic transducer comprising:

measuring a time of flight of a pulse emitted from each transducer element and detected by a sensor;

determining a distance between each transducer element and the sensor based on the time of flight; and

determining the actual location of each transducer element based on the determined distance.

31. A method of controlling an output of a phased array ultrasonic transducer having a plurality of transducer elements, comprising:

generating an initial file having the expected (x,y,z) location of each transducer element based on a shape or a design of the phased array ultrasonic transducer;

mapping the surface of the phased array ultrasonic transducer to determine the actual (x,y,z) location of each transducer element relative to an expected location of the transducer element, mapping the surface further comprising

measuring a time of flight of a pulse emitted from each transducer element and detected by a sensor,

determining a distance between each transducer element and the sensor based on the time of flight, and

determining the actual location of each transducer element based on the determined distance;

comparing the actual locations of transducer elements and respective expected locations of transducer elements;

generating an updated file having actual locations of certain transducer elements if the actual location of a transducer element deviates from the expected location of the transducer element; and

adjusting drive signals of certain transducer elements based on the updated file to control the output of the phased array ultrasonic transducer.