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CN-122003301-A - Ultrasound probe including an array of transducer elements

CN122003301ACN 122003301 ACN122003301 ACN 122003301ACN-122003301-A

Abstract

The present specification relates to an ultrasound probe comprising an array (200) of transducer elements (201), the probe comprising-a first piezoelectric layer (210) divided into first piezoelectric electronic elements (211), each first piezoelectric electronic element comprising a first electrode (215) located on a first face (210A) of the first piezoelectric layer, the first dielectric layer comprising a first ground electrode (213) located on a second face (210B) of the first piezoelectric layer, -a second piezoelectric layer (220) above the first piezoelectric layer, the second piezoelectric layer comprising a second ground electrode (223) located on a first face (220A) of the second piezoelectric layer and divided into second piezoelectric electronic elements (221), each second piezoelectric electronic element comprising a second electrode (225) located on a second face (220B) of the second piezoelectric layer, -a ground plane (203) located between the second face of the first piezoelectric layer and the first face of the second piezoelectric layer, -a first collector electrode (230) assembled to the first face of the first piezoelectric layer, -a second collector electrode (240) assembled to the second face of the second piezoelectric layer.

Inventors

  • Mathieu Legro
  • Christopher Nodal
  • Tang Ji Moriant
  • Mary Deneo

Assignees

  • 维蒙公司

Dates

Publication Date
20260508
Application Date
20240924
Priority Date
20231012

Claims (18)

  1. 1. An ultrasound probe (400) comprising an array (200) of piezoelectric transducer elements (201), the array comprising: -a first piezoelectric layer (210) divided into a plurality of first piezoelectric elements (211), each first piezoelectric element comprising a first electrode (215) located on a first face (210A) of the first piezoelectric layer (210), the first dielectric layer further comprising a first ground electrode (213) on a second face (210B) opposite to the first face of the first piezoelectric layer; -a second piezoelectric layer (220) stacked over the first piezoelectric layer, the second dielectric layer comprising a second ground electrode (223) located on a first face (220A) of the second piezoelectric layer and divided into a plurality of second piezoelectric electronic elements (221), each second piezoelectric element comprising a second electrode (225) located on a second face (220B) opposite to the first face of the second piezoelectric layer; The first and second piezoelectric layers extend along a main plane, and the second piezoelectric element (221) is aligned with the first piezoelectric element (211) in a direction transverse to the main plane; -a ground plane (203) located between and in contact with the second face (210B) of the first piezoelectric layer (210) and the first face (220A) of the second piezoelectric layer (220); -a first collector electrode (230) assembled to a first face (210A) of the first piezoelectric layer (210) and comprising a first conductive track (232) coupled with the first electrode (215); -a second collector electrode (240) assembled onto a second face (220B) of the second piezoelectric layer (220) and comprising a second conductive track (242) coupled with the second electrode (225); Each piezoelectric transducer element (201) comprises one of said first piezoelectric elements (211) aligned with one of said second piezoelectric elements (221), and a portion of said ground plane (203) between said aligned first and second piezoelectric elements.
  2. 2. The ultrasound probe of claim 1, wherein first and second electrodes (215, 225) of the same piezoelectric transducer element (201) are electrically coupled to each other, e.g., first and second metal tracks (232, 242) coupled to the first and second electrodes, respectively.
  3. 3. The ultrasound probe of claim 1 or 2, wherein the first piezoelectric layer (210) and/or the second piezoelectric layer (220): including a piezoelectric composite material, and/or -Having a thickness between 0.5mm and 10 mm.
  4. 4. The ultrasound probe of any of claims 1 to 3, wherein the ground plane (203): is a metal layer, for example a metal plate, for example made of copper, aluminum or brass, and/or -Extending beyond the stack of the first and second piezoelectric layers (210, 220) by a connection pad (204) adapted to electrically couple the ground plane to ground outside the stack, and/or -Having a thickness between 10 μm and 500 μm.
  5. 5. The ultrasound probe of any of claims 1 to 4, wherein the array (200) comprises: -a first thickness (e 1) of piezoelectric material of the first piezoelectric layer (210) between two adjacent first piezoelectric elements (211) on a first face of the ground plane (203), the first thickness being smaller than the thickness of the first piezoelectric layer, and/or -A second thickness (e 2) of piezoelectric material of the second piezoelectric layer (220) between two adjacent second piezoelectric elements (221) on a second face of the ground plane (203) opposite to the first face of the ground plane, the second thickness being smaller than the thickness of the second piezoelectric layer.
  6. 6. The ultrasound probe of any of claims 1 to 5, wherein the array (200) has a curved shape, and the principal plane is curved.
  7. 7. The ultrasound probe (400) of any of claims 1 to 6, wherein the array (200) further comprises a first acoustic impedance matching layer (202) between the first piezoelectric layer (210) and the first collector electrode (230), the first acoustic impedance matching layer being configured such that each piezoelectric transducer element (201) comprises a portion of the first acoustic impedance matching layer between the first electrode (215) and the first collector electrode, the first acoustic impedance matching layer being made of graphite, for example.
  8. 8. The ultrasound probe (400) of any of claims 1 to 7, further comprising a second acoustic impedance matching layer (311), the first collector electrode (230) being located between the first piezoelectric layer (210) and the second acoustic impedance matching layer, such as between a first acoustic impedance matching layer (202) and the second acoustic impedance matching layer.
  9. 9. The ultrasound probe of any of claims 1 to 8, wherein: -the first collector electrode (230) comprises a first insulating substrate (231), such as a flexible insulating substrate, on or in which the first metal track (232) is located and is coupled with a first contact pad (234) coupled or connected to the first electrode (215), and/or -The second collector electrode (240) comprises a second insulating substrate (241), such as a flexible insulating substrate, the second metal track (242) being located on or in the second insulating substrate and being coupled with a second contact pad (244) coupled or connected to the second electrode (225).
  10. 10. The ultrasound probe (400) of any of claims 1 to 9, wherein the first and second piezoelectric elements of each piezoelectric transducer element are divided into a plurality of portions, the portions of the same piezoelectric transducer element sharing the same first and second electrodes.
  11. 11. The ultrasound probe of any of claims 1 to 10, wherein the first piezoelectric element (211) and the second piezoelectric element (221) are distributed in two orthogonal directions of the main plane.
  12. 12. The ultrasound probe (400) of any of claims 1 to 11, further comprising an acoustic attenuation layer (312) on the second collector electrode (240), a shaper (413) on the acoustic attenuation layer, and a printed circuit board (414) on the shaper, the ground plane (203) being electrically coupled to ground via the printed circuit board, and the first and second electrodes of the same piezoelectric transducer element being electrically coupled to each other, e.g. also by the printed circuit board.
  13. 13. A method for manufacturing an array (200) of piezoelectric transducer elements (201) of an ultrasound probe, the method comprising: -forming a stack comprising a first piezoelectric layer (210) provided with a first ground electrode (213) on a second face (210B), a ground plane (203) on the second face (210B) of the first piezoelectric layer, and a second piezoelectric layer (220) provided with a second ground electrode (223) on a first face (220A) located on the ground plane, the first and second piezoelectric layers extending along a main plane; -cutting the first piezoelectric layer (210) over all or part of its thickness into a plurality of first piezoelectric elements (211), each comprising a first electrode (215) located on a first face of the first piezoelectric layer (210) opposite to a second face of the first piezoelectric layer; -cutting the second piezoelectric layer (220) over all or part of its thickness into a plurality of second piezoelectric elements (221), each comprising a second electrode (225) connected to a second face (220B) of the second piezoelectric layer (220) opposite to the first face of the second piezoelectric layer; the second piezoelectric element is aligned with the first piezoelectric element in a direction transverse to the principal plane; Cutting of the first and second piezoelectric layers is stopped at least before the ground plane; -assembling a first collector electrode (230) comprising a first conductive track (232) onto a first face (210A) of a cut first piezoelectric layer (210), said assembling comprising electrically connecting said first conductive track (232) to said first electrode (215); -assembling a second collector electrode (240) comprising a second conductive track (242) to a second face (220B) of the diced second piezoelectric layer (220), the assembling comprising electrically connecting the second conductive track (242) to the second electrode (225); each piezoelectric transducer element (201) comprises a first piezoelectric element (211) aligned with one of the second piezoelectric elements (221), and a portion of a ground plane (203) between the aligned first and second piezoelectric elements.
  14. 14. The method of claim 13, further comprising forming an electrical connection between a first electrode and a second electrode of the same piezoelectric transducer element (201), for example by electrically coupling with a first metal track and a second metal track coupled to the first electrode and the second electrode, respectively.
  15. 15. The method according to claim 13 or 14, wherein the first and second piezoelectric layers (210, 220) are not cut through their entire thickness in order to maintain the thickness (e 1, e 2) of piezoelectric material on at least one of the two faces of the ground plane (203).
  16. 16. The method of any of claims 13 to 15, wherein the step of dicing the first and second piezoelectric layers (210, 220) further comprises dicing the first and second piezoelectric elements (211, 221) a second time to divide each piezoelectric transducer element (201) into portions sharing the same first and second electrodes (215, 225), the second time dicing being shallower than the dicing used to form the first and second piezoelectric elements.
  17. 17. The method of any of claims 13-16, further comprising assembling a first acoustic impedance matching layer (202) to a first face (210A) of the first piezoelectric layer (210) prior to the step of assembling the first collector electrode (230) such that the first acoustic impedance matching layer is located in the array (200) between the first piezoelectric layer and the first collector electrode, cutting the first piezoelectric layer including cutting the first acoustic impedance matching layer through its entire thickness.
  18. 18. The method according to any of claims 13 to 17, further comprising the step of bending the array (200) after the step of dicing the first and second piezoelectric layers, e.g. after the step of assembling the first and second collector electrodes.

Description

Ultrasound probe including an array of transducer elements This patent application is based on and claims priority of french patent application 2310965 entitled "Ultrasonic probe WITH AN ARRAY of transducer elements" filed on day 10 and 12 of 2023, which is considered an integral part of this specification within the scope of legal regulations. Technical Field The present disclosure relates generally to ultrasound probes having arrays of transducer elements, which may be referred to as "array ultrasound probes", and in particular low frequency array ultrasound probes, i.e. adapted to operate at frequencies typically below 2 MHz. The present description relates in particular to convex array ultrasound probes. Background An array ultrasound probe typically includes a plurality of transducer elements arranged side-by-side in a matrix array. The transducer elements of the matrix array are preferably addressed individually, rather than in rows and columns. When the transducer elements are piezoelectric transducer elements, each transducer element typically comprises a layer of piezoelectric material (or piezoelectric layer), and front and rear electrodes adapted to apply and/or recover an excitation electrical signal to and/or from the transducer element in order to convert it into an electrical signal. One of the front and rear electrodes may be connected to ground and the other electrode may be dedicated to signals. Array ultrasound probes can be used for 2D or even 3D imaging, especially in medical imaging applications. There is a need for an ultrasound probe having an array of piezoelectric transducer elements that is adapted to operate at low frequencies, i.e. at frequencies typically below 2MHz, and that at least partially overcomes some of the disadvantages of known array ultrasound probes. It is desirable to have such an array ultrasound probe that is also capable of bending. Disclosure of Invention One embodiment overcomes all or part of the disadvantages of known array ultrasound probes. One embodiment provides an ultrasound probe comprising an array of piezoelectric transducer elements, the array comprising: -a first piezoelectric layer divided into a plurality of first piezoelectric elements, each first piezoelectric element comprising a first electrode on a first face of the first piezoelectric layer, the first dielectric layer further comprising a first ground electrode on a second face of the first piezoelectric layer opposite the first face; -a second piezoelectric layer stacked over the first piezoelectric layer, the second dielectric layer comprising a second ground electrode on a first face of the second piezoelectric layer and divided into a plurality of second piezoelectric elements, each second piezoelectric element comprising a second electrode on a second face of the second piezoelectric layer opposite the first face; the first and second piezoelectric layers extend along a principal plane and the second piezoelectric element is aligned with the first piezoelectric element in a direction transverse to the principal plane; -a ground plane located between and in contact with the second face of the first piezoelectric layer and the first face of the second piezoelectric layer; -a first collector electrode assembled to a first face of the first piezoelectric layer and comprising a first conductive track coupled to a first electrode; -a second collector electrode assembled to a second face of the second piezoelectric layer and comprising a second conductive track coupled to a second electrode; Each piezoelectric transducer element includes a first piezoelectric element aligned with one of the second piezoelectric elements and a portion of the ground plane between the first pair Ji Yadian of sub-elements and the second pair Ji Yadian of sub-elements. According to one embodiment, the first and second electrodes of the same piezoelectric transducer element are electrically coupled to each other, e.g. a first metal track and a second metal track coupled to the first and second electrodes, respectively, are electrically coupled to each other. According to one embodiment, the first piezoelectric layer and/or the second piezoelectric layer: including a piezoelectric composite material, and/or -Having a thickness between 0.5mm and 10 mm. According to one embodiment, the ground plane: a metal layer, for example a metal plate, for example made of copper, aluminum or brass, and/or Extending beyond the stack of first and second piezoelectric layers by a connection pad adapted to electrically couple the ground plane to a ground outside said stack, and/or -Having a thickness between 10 μm and 500 μm. According to one embodiment, the array comprises: A first thickness of piezoelectric material of a first piezoelectric layer located between two adjacent first piezoelectric elements on a first face of the ground plane, the first thickness being smaller than the thickness of the first piezoelectric layer, and/o