ULTRASOUND TRANSDUCER ASSEMBLY

• US 20170065253A1
• Filed: 09/02/2016
• Published: 03/09/2017
• Est. Priority Date: 09/03/2015
• Status: Active Grant

• Current Assignee: FUJIFILM SonoSite, Inc. (Fujifilm Holdings Corporation)
• Original Assignee: FUJIFILM SonoSite, Inc. (Fujifilm Holdings Corporation)
• Inventors: Frey, Gregg, Hsu, Simon, Li, Wei
• Granted Patent: US 10,716,542 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 8/4444 related to the probe
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: B06B 1/0622 on one surface
• CPC Class Codes: B06B 1/0644 using a single piezoelectric element B06B1/0688 takes precedence
• CPC Class Codes: B06B 1/067 which is used as, or combined with, an impedance matching layer
• CPC Class Codes: G01N 2291/0231 Composite or layered materials
• CPC Class Codes: G01N 29/2406 Electrostatic or capacitive probes, e.g. electret or cMUT-probes
• CPC Class Codes: G01N 29/2437 Piezoelectric probes
• CPC Class Codes: H10N 30/072 by laminating or bonding of piezoelectric or electrostrictive bodies
• CPC Class Codes: H10N 30/088 by cutting or dicing
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices

Abstract

Ultrasound transducer assemblies and associated systems and method are disclosed herein. In one embodiment, an ultrasound transducer assembly includes at least one matching layer overlies a transducer layer. A plurality of kerfs extends at least into the matching layer. In some aspects, the kerfs are at least partially filled with a filler material that includes microballoons and/or microspheres.

Claims

1. An ultrasound transducer assembly comprising:

a transducer layer configured emit ultrasound energy in an axial direction;

a matching layer overlaying the transducer layer in the axial direction; and

a plurality of kerfs extending into at least the matching layer, wherein the kerfs are at least partially filled with a filler material comprising microballoons or microspheres.

2. The ultrasound transducer assembly of claim 1 wherein the plurality of kerfs include a plurality of first kerfs and a plurality of second kerfs, wherein the first kerfs have a first depth in the axial direction, wherein the second kerfs have a second depth in the axial direction greater than the first depth.

3. The transducer assembly of claim 2, further comprising a backing layer underlying the transducer layer.

4. The transducer assembly of claim 2, further comprising a dematching layer between the transducer layer and the backing layer, wherein the second kerfs extend into the backing layer through the matching layer, the transducer layer and the dematching layer.

6. The transducer assembly of claim 1, further comprising a groove formed into the filler material, wherein the kerfs have a first width in an azimuthal direction, and wherein the groove has a second width in the azimuthal direction less than the first width.

7. The transducer assembly of claim 6 wherein the second width is greater than one half of the first width.

8. The transducer assembly of claim 6 wherein the second width is less than one quarter of the first width.

9. The transducer assembly of claim 6 wherein the groove has a depth in the axial direction less than a thickness of the matching layer.

10. The transducer assembly of claim 6 wherein the groove has a depth in the axial direction greater than a thickness of the matching layer.

11. The transducer assembly of claim 1 wherein the depths of the filler material in individual kerfs in an axial direction varies in an azimuthal direction.

12. The transducer assembly of claim 1 wherein the depths of the filler material in individual kerfs in an axial direction varies in an elevation direction.

13. The transducer assembly of claim 1 wherein the filler material includes an acoustical impedance that is graduated in an axial direction.

5. The transducer assembly of claim 5 wherein the acoustical impedance of the dematching layer is less than the acoustical impedance of tungsten carbide.

14. A method of constructing an ultrasound transducer assembly, the method comprising:

bonding an upper surface of a piezoelectric layer to a lower surface of a matching layer;

bonding a lower surface of the piezoelectric layer to a dematching layer;

forming a first plurality of kerfs extending into the matching layer; and

forming a second plurality of kerfs extending through the matching layer, the piezoelectric layer and the dematching layer, wherein a depth of the first plurality of kerfs is less than a depth of the second plurality of kerfs.

15. The method of claim 14, further comprising bonding an upper surface of a backing layer to a lower surface of the dematching layer.

16. The method of claim 14, further comprising at least partially filling the first kerfs and the second kerfs with a filler material comprising microballoons.

17. The method of claim 16, further comprising forming a groove in the filler material in at least one of the first kerfs or the second kerfs.

18. The method of claim 17, wherein the matching layer has a thickness, and wherein forming the groove comprises forming a groove having a depth in the elevation direction less than the thickness of the matching layer.

19. The method of claim 18, further comprising varying the depths of the filler material in individual kerfs in an azimuthal direction.

20. An ultrasound transducer assembly, comprising:

a piezoelectric layer comprising a plurality of piezoelectric transducer elements configured emit ultrasound energy;

a plurality of matching layers overlaying the piezoelectric layer, wherein a Z-axis extends through the plurality of matching layers and the piezoelectric layer; and

a plurality of first kerfs and a plurality of second kerfs extending into at least the plurality of matching layers, wherein the first kerfs have a first depth with respect to the Z-axis, wherein the second kerfs have a second depth with respect to the Z-axis, wherein the second depth is greater than the first depth, and wherein the kerfs are at least partially filled with a composite filler material comprising two or more materials.

21. The ultrasound transducer assembly of claim 20 wherein the composite material comprises two or more materials having different acoustic impedances.

22. The ultrasound transducer assembly of claim 20 wherein the composite filler material has an acoustic impedance within about 10% of the acoustic impedance of air.

23. The ultrasound transducer assembly of claim 20 wherein the composite material includes microballoons suspended in an epoxy, and wherein the composite material has an acoustic impedance within about 5% of the acoustic impedance of air.

24. The ultrasound transducer assembly of claim 20, further comprising:

a backing layer underlying the piezoelectric layer; and

a dematching layer between the transducer layer and the backing layer, wherein the second kerfs extend into the backing layer through the one or more matching layers, the piezoelectric layer and the dematching layer.

25. The transducer assembly of claim 24 wherein an acoustical impedance of the dematching layer is substantially different from the acoustical impedance of tungsten carbide.

26. The transducer assembly of claim 24 wherein an acoustical impedance of the dematching layer is less than an acoustical impedance of the piezoelectric layer.

27. The transducer assembly of claim 20 wherein the piezoelectric layer and the plurality of matching layers have a length extending along an azimuthal axis, and further comprising:

a groove formed into the composite filler material, wherein the first and second kerfs have a first width relative to the azimuthal axis, and wherein the groove has a second width relative to the azimuthal axis less than the first width.

28. The transducer assembly of claim 20 wherein the piezoelectric layer and the plurality of matching layers have a length extending along an azimuthal axis, and wherein the first depths and the second depths of the composite filler materials in corresponding individual first and second kerfs vary relative to the azimuthal axis.

29. The transducer assembly of claim 20 wherein the piezoelectric layer and the plurality of matching layers have a width extending along an elevation axis, wherein the first depths and the second depths of the composite filler materials in corresponding individual first and second kerfs vary relative to the elevation axis.

30. The transducer assembly of claim 20 wherein the composite filler material has a graduated acoustical impedance with respect to the z-axis.