Ultrasonic array with attenuating electrical interconnects

• US 5,732,706 A
• Filed: 03/22/1996
• Issued: 03/31/1998
• Est. Priority Date: 03/22/1996
• Status: Expired due to Term

• Current Assignee: Lockheed Martin IR Imaging Systems, Inc. (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin IR Imaging Systems, Inc. (Martin Marietta Corporation)
• Inventors: Haase, Wayne C., Martinelli, Michael A., White, Timothy E., Butler, Neal R., Hatch, Marcus, Erikson, Kenneth R., Vock, Curtis A.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US08/621,104
• Time in Patent Office: 739 Days
• Field of Search: 128/660.07, 128/661.01, 128/662.03, 128/663.01, 73/625, 73/626, 364/413.25, 310/328, 310/334, 310/335, 310/336, 310/348
• US Class Current: 600/437
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/4483 characterised by features of the ultrasound transducer
• CPC Class Codes: B06B 1/0629 Square array
• CPC Class Codes: G01S 15/8925 the array being a two-dimensional transducer configuration, i.e. matrix or orthogonal linear arrays
• CPC Class Codes: G10K 11/02 Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
• CPC Class Codes: G10K 11/30 using refraction, e.g. acoustic lenses

Abstract

An array of ultrasonic transducers, where each of the ultrasonic transducers has a matching layer end and a driving layer/individually isolated end. A bump bond connects each one of the ultrasonic transducers to a substrate. A high voltage electrical conductor is connected to at least one driving layer/individually isolated end to provide a drive signal to at least one of the ultrasonic transducers. A conductive/matching layer is disposed to electrically connect each matching layer end. An outer matching layer is connected to the conductive/matching layer. The bump bond is an indium or solder bump bond having a contact area for contact with an ultrasonic transducer less than 20 percent of the driving layer/individually isolated end for the contacted ultrasonic transducer so as to provide mechanical stability while reducing cross talk among the plurality of ultrasonic transducers.

Claims

1. An ultrasonic array comprising:

(a) a plurality of ultrasonic transducers, each of the plurality of ultrasonic transducers having a matching layer/common electrode end and a driving layer/individually isolated end;

(b) a means for bump bonding each one of the plurality of ultrasonic transducers to a substrate;

(c) a high voltage electrical conductor connected to at least one driving layer/individually isolated end to provide a drive signal to at least one of the plurality of ultrasonic transducers;

(d) a conductive layer disposed to electrically connect each matching layer end; and

(e) an outer matching layer connected to the conductive layer wherein the bump bonding means is constructed of a size so as to provide mechanical stability while reducing cross talk among the plurality of ultrasonic transducers.

2. The apparatus of claim 1 wherein the means for bump bonding each one of the plurality of ultrasonic transducers to a substrate further comprises an indium bump or solder bump bond wherein the indium bump or solder bump bond comprises an area in contact with an ultrasonic transducer of less than 20 percent of the driving layer/individually isolated end for the ultrasonic transducer.

3. The apparatus of claim 1 wherein the substrate further comprises a semiconductor.

4. The apparatus of claim 1 wherein the plurality of ultrasonic transducers further comprise a piezoelectric element.

5. The apparatus of claim 1 wherein the plurality of ultrasonic transducers further comprise an array of receivers.

6. The apparatus of claim 1 wherein the plurality of ultrasonic transducers further comprise an array of transmitters.

7. The apparatus of claim 1 wherein the plurality of ultrasonic transducers further comprise at least one transmitter.

8. The apparatus of claim 1 wherein the plurality of ultrasonic transducers further comprise a plurality of transmitters arranged in a predetermined pattern.

9. The apparatus of claim 8 wherein the predetermined pattern is selected from the group consisting of a rectangular pattern, a circular pattern, a reticulated pattern, a diagonal pattern, a grid pattern, a random pattern, a triangular pattern, a cross pattern and an oval pattern.

10. The apparatus of claim 8 wherein the plurality of transmitters are connected with a plurality of high voltage electrical conductors.

11. The apparatus of claim 1 wherein the means for bonding has a predetermined size that is small relative to the size of an ultrasonic transducer.

12. The apparatus of claim 1 wherein the means for bonding comprises an indium bump bond connected to a stepped or sloped conductor potted in an acoustic matching medium.

13. The apparatus of claim 1 wherein one matching layer comprises stepped or sloped layers on at least one surface and the outer matching layer comprises stepped layers on at least one surface.

14. The apparatus of claim 1 further comprising an acoustic lens located in an acoustic medium or fluid between a source of ultrasonic energy of a predetermined wavelength and the plurality of ultrasonic transducers wherein the acoustic lens is constructed so as to provide a gradual transition from one medium or fluid to another.

15. The apparatus of claim 14 wherein the acoustic lens has a surface shaped as a binary concave lens.

16. The apparatus of claim 14 wherein the acoustic lens comprises a graded surface area having gradations less than the predetermined wavelength.

17. The apparatus of claim 1 wherein the conductive layer further comprises a plurality of isolated conductive matching layer tiles.

18. The apparatus of claim 1 wherein the plurality of ultrasonic transducers further comprise a plurality of receivers arranged in a predetermined pattern.

19. The apparatus of claim 18 wherein the means for bump bonding each one of the plurality of ultrasonic transducers to a substrate further comprises an indium bump or solder bump bond wherein the indium bump or solder bump bond comprises an area in contact with an ultrasonic transducer in the range of 10 percent to 5 percent of the driving layer/individually isolated end for the ultrasonic transducer.

20. The apparatus of claim 1 wherein the matching layer/common electrode end further comprises a lossy matching layer so as to further reduce cross talk.

21. An adaptive ultrasound array comprising:

(a) an array of ultrasonic transducers having a first plurality of receivers and a second plurality of transmitters having a signal;

(b) means for switching each one of the first plurality of receivers and each one of the second plurality of transmitters connected to the signal having a receive signal and a transmit signal; and

(c) means for scanning the array of ultrasonic transducers to select at least one

receiver from the plurality of receivers and to select at least one transmitter from the plurality of transmitters that provide a useable signal having a signal to noise ratio above a predetermined value; and

(d) means for processing the receive signal and transmit signal from the at least one selected receiver and the at least one transmitter to adaptively process the receive signal and transmit signal.

22. The apparatus of claim 21 wherein the means for processing the receive signal and transmit signal further comprises a microprocessor.

23. The apparatus of claim 21 wherein the means for processing the receive signal and transmit signal further comprises a personal computer.

24. A method for operating an adaptive ultrasonic array comprising the steps of:

(a) transmitting an ultrasonic pulse from the adaptive ultrasonic array to a target;

(b) receiving a first peak return pulse from the target with the adaptive ultrasonic array;

(c) receiving a second peak return pulse from the target with the adaptive ultrasonic array and noting a time of the second peak return pulse; and

(d) adjusting imaging of the target with the adaptive ultrasonic array with the time of the first peak return pulse and the time of the second peak return pulse.

25. An ultrasonic system comprising:

(a) a housing filled with a known ultrasound coupling fluid;

b) an ultrasonic window mounted at a first end of the housing;

c) a multi-element acoustic lens mounted within the housing and located to receive energy from the ultrasonic window;

d) piezoelectric material; and

e) an integrated circuit wherein the piezoelectric material and silicon integrated circuit are electrically connected by a bump bonding means for electrical connection, wherein the bump bonding means is constructed so as to provide mechanical stability while reducing cross talk among the plurality of ultrasonic transducers.

26. The ultrasonic system of claim 25 wherein the integrated circuit comprises:

(a) a plurality of unit cells each having a unit cell output;

(b) a plurality of analog-to-digital converters (ADCs) each having an input connected to a unit cell output and each having an ADC output; and

(c) means for multiplexing coupled to the ADC output.

27. The ultrasonic system of claim 25 wherein a unit cell comprises:

(a) a bump means for connection to an ultrasonic transducer array;

(b) sample-and-hold circuits connected to receive signals through the bump means;

(c) a shift register connected to the sample-and-hold circuit; and

(d) a variable gain preamplifier connected to amplify signals received through the bump means.

28. The ultrasonic system of claim 25 wherein the multi-element acoustic lens comprises at least two lenses where the each of the at least two lenses comprises a graded surface area having gradations less than the predetermined wavelength.