Acoustic lens for micromachined ultrasound transducers

Patent metadata

Field	Value
Publication number	US-10770058-B2
Application number	US-201815995015-A
Country	US
Kind code	B2
Filing date	May 31, 2018
Priority date	Mar 15, 2013
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

Matching layers configured for use with ultrasound transducers are disclosed herein. In one embodiment, a transducer stack can include a capacitive micromachined ultrasound transducer (CMUT), an acoustic lens, and a matching layer therebetween. The matching layer can be made from a compliant material (e.g. an elastomer and/or an liquid) and configured for use with CMUTs. The matching layer can include a bottom surface overlying a top surface of the transducer and a top surface underlying a bottom surface of the lens.

First claim

We claim:

1. An ultrasonic transducer stack comprising:
a first matching layer having a first top surface and a first bottom surface, wherein the first matching layer comprises a compliant material, and wherein the first matching layer has a first thickness and a first acoustic impedance;
a lens layer having a second bottom surface comprising a polymethylpentene or a thermoset cross-linked styrene copolymer material that is textured overlying the first top surface, and a second top surface, wherein the lens layer has a second thickness and a second acoustic impedance; and
a transducer layer having a third top surface underlying the first bottom surface and the second bottom surface, wherein the transducer layer includes a micromachined ultrasound transducer configured to generate ultrasound at a center frequency, and wherein the third top surface comprises an upper membrane of the transducer.

2. The transducer stack of claim 1 wherein the compliant material comprises a PDMS-type silicone.

3. The transducer stack of claim 1 wherein the compliant material has a Young's Modulus of less than 100 MPa.

4. The transducer stack of claim 1 wherein the first thickness is less than the second thickness.

5. The transducer stack of claim 1 wherein the first thickness is less than ¼ wavelength of the center frequency.

6. The transducer stack of claim 1 wherein the center frequency is greater than 15 MHz.

7. The transducer stack of claim 1 wherein the second bottom surface is textured with a plurality of ridges and a plurality of grooves therebetween.

8. The transducer stack of claim 1 wherein the compliant layer comprises a matrix material, and wherein the first matching layer comprises a composite layer made of a first plurality of micron-sized particles and a second plurality of nano-sized particles combines with the matrix material.

9. The transducer stack of claim 1 wherein the first plurality of micron-sized particles are selected based on a desired acoustic impedance of the composite material.

10. The transducer stack of claim 1 , further comprising a second matching layer disposed between the first matching layer and the lens layer.

11. An ultrasound transducer stack for external use, the ultrasound transducer stack comprising:
a first matching layer having a first top surface and a first bottom surface, wherein the first matching layer includes a first compliant material and wherein the first matching layer has a first acoustic impedance;
a lens layer having a second bottom surface comprising a polymethylpentene or a thermoset cross-linked styrene copolymer material that is textured with a plurality of ridges and a plurality grooves therebetween overlying the first top surface and a second top configured to be placed against a subject's skin, wherein the lens layer has a second acoustic impedance different from the first acoustic impedance; and
a third layer having a third top surface underlying the first bottom surface and the second bottom surface, wherein the third layer includes a micromachines ultrasound transducer configured to generate ultrasound.

12. The transducer stack of claim 11 wherein the compliant material is a PDMS-type silicone.

13. The transducer stack of claim 11 wherein the complaint material includes water.

14. The transducer stack of claim 11 wherein the third top surface comprises an anti-corrosive material.

15. The transducer stack of claim 11 wherein the lens layer is removably attached to the first matching layer.

16. The transducer stack of claim 11 wherein the first matching layer includes a first plurality of micron-sized and second plurality of nano-sized particles combined with the compliant material to form a composite material.

17. The transducer stack of claim 11 wherein the compliant material includes a fluid.

18. The transducer stack of claim 11 wherein the micromachines ultrasound transducer is a CMUT.

19. The transducer stack of claim 11 wherein the micromachined ultrasound transducer is a PMUT.

Assignees

• Fujifilm Sonosite Inc

Inventors

• Li Wei
• Dunham Paul
• Aw Chak-Yoon
• Chaggares N Chris

Classifications

• G01N29/2437

  Piezoelectric probes · CPC title

• B81B2201/02

  Sensors · CPC title

• G01N29/06

  Visualisation of the interior, e.g. acoustic microscopy {(medical or veterinary diagnosis using sonic waves A61B8/00; representation of acoustic wave distribution G01H3/125, G01H9/002; short-range imaging systems using reflection of acoustic waves G01S15/8906)} · CPC title

• G01N29/28

  providing acoustic coupling {, e.g. water (impedance matching G10K11/02)} · CPC title

• G01N29/221

  Arrangements for directing or focusing the acoustical waves (electronic orientation or focusing G01N29/262; sound directing or focusing G10K11/26; mechanical steering of sound transducers or their beams G10K11/35) · CPC title