# US 2025/0083188 A1 · Ultrasound transducer with reduced cross-talk and method of manufacture

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- Number: US 2025/0083188 A1
- Document ID: US20250083188A1
- Status: Published application
- Kind: A1
- Application number: 18/367,387
- Filed: 2023-09-12
- Published: 2025-03-13
- Earliest claimed: 2023-09-12
- Inventors: Roger Zemp; Mohammad Rahim Sobhani
- Web page: https://patentgrep.com/patent/US20250083188A1

## CPC

- B06B 1/06: operating with piezoelectric effect or with electrostriction (piezoelectric or electrostrictive devices per se H10N30/00)
- B06B 1/0622: {on one surface}
- B06B 1/0629: {Square array}
- H10N 30/06: Forming electrodes or interconnections, e.g. leads or terminals
- H10N 30/088: by cutting or dicing
- H10N 30/87: Electrodes or interconnections, e.g. leads or terminals
- B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

An ultrasonic transducer device has an acoustic layer with a two-dimensional array of acoustically active elements, a first electrode layer on a first side of the acoustic layer and a second electrode layer on a second side of the acoustic layer. The first electrode layer and the second electrode layer have non-parallel electrodes that permit each acoustically active element in the two-dimensional array to be separately addressable by a controller. A series of kerfs separate adjacent acoustically active elements in the two-dimensional array of acoustically active elements of acoustically active elements, the series of kerfs being filled with a low dielectric, low acoustic impedance filler.

## Claims

### Claim 1

An ultrasound transducer device, comprising:
an acoustically active layer comprising an array of acoustically active elements in the acoustically active layer;
a first electrode layer on a first side of the acoustically active layer and a second electrode layer on a second side of the acoustically active layer, each of the first electrode layer and the second electrode layer comprising a plurality of elongate electrodes, each of the plurality of elongate electrodes of the first electrode layer and the second electrode layer having an electrical connection and wherein the elongate electrodes of the first electrode layer are angled relative to the first set of electrodes to permit row-column addressing within the array of acoustically active elements;
a backing layer adjacent to the second electrode layer;
a first set of kerfs in the acoustically active layer that defines the array of acoustically active elements, the first set of kerfs comprising a low impedance filler that has a lower acoustic impedance than the acoustically active layer;
a second set of kerfs in the first electrode layer that defines the plurality of elongate electrodes in the first electrode layer, the second set of kerfs extending at least partly into the acoustically active layer; and
a third set of kerfs in the second electrode layer that defines the plurality of elongate electrodes in the second electrode layer, the third set of kerfs extending at least partly into the backing layer, the acoustically active layer, or both the backing layer and the acoustically active layer.

### Claim 2 (depends on 1)

The ultrasound transducer device of claim 1, wherein the array of acoustically active elements is a two-dimensional array.

### Claim 3 (depends on 1)

The ultrasound transducer device of claim 1, wherein at least a portion of the first electrode layer, the second electrode layer, and the array of acoustically active elements are arranged in a top-orthogonal-to-bottom electrode configuration.

### Claim 4 (depends on 1)

The ultrasound transducer device of claim 1, wherein at least a portion of the first electrode layer, the second electrode layer, and the array of acoustically active elements are arranged in an aperiodic gridded array, such that a vector distance between any pairs of elements is unique.

### Claim 5 (depends on 1)

The ultrasound transducer device of claim 1, wherein the second set of kerfs and the third set of kerfs comprise a dielectric filler that has a higher electrical impedance than the plurality of elongate electrodes.

### Claim 6 (depends on 5)

The ultrasound transducer device of claim 5, wherein the dielectric filler is atmospheric air or an inert gas.

### Claim 7 (depends on 1)

The ultrasound transducer device of claim 1, wherein the array of acoustically active elements are in a grid pattern and the electrodes in the first electrode layer and the second electrode layer connect adjacent acoustically active elements at 45-degrees relative to the grid pattern.

### Claim 8 (depends on 1)

The ultrasound transducer device of claim 1, wherein the acoustically active layer comprising a piezoelectric material, an electrostrictive material, an electrostrictive relaxor material, micromachined membranes and gaps, or capacitive micromachined ultrasound transducers.

### Claim 9 (depends on 1)

The ultrasound transducer device of claim 1, wherein the second set of kerfs and the third set of kerfs extend into the acoustically active stack only in regions where the dielectric filler is present.

### Claim 10 (depends on 1)

The ultrasound transducer device of claim 1, comprising a stack of acoustically active layers, each acoustically active layer having a first electrode layer and a second electrode layer.

### Claim 11 (depends on 1)

The ultrasound transducer device of claim 1, further comprising one or more bias tees selectively connected to the electrical connection of one or more electrodes of the plurality of elongate electrodes.

### Claim 12 (depends on 1)

The ultrasound transducer device of claim 1, further comprising a housing that is a handheld housing, a wearable housing, a convex housing, or a concave housing.

### Claim 13

A method for manufacturing an ultrasound transducer device, comprising the steps of:
mounting a bottom surface of a bulk material layer to a substrate;
cutting into a top surface of the bulk material layer to create an array of pillars separated by a first set of kerfs that extend partly through a thickness of the bulk material layer, the bulk material layer comprising an acoustically active material;
filling the first set of kerfs with a low impedance filler to form a composite layer, the low impedance filler having a lower acoustic impedance than the acoustically active material, and then lapping the top surface of the bulk material layer to form a composite layer in the bulk material layer;
forming a first electrode layer on the top surface of the bulk material layer by patterning electrodes in the first electrode layer and providing an electrical connection for each electrode to an electrical device;
forming a backing layer on an opposite side of the first electrode layer relative to the bulk material layer, the backing layer being formed such that an outer surface of the backing layer opposite the first electrode layer is substantially parallel to the bottom surface of the bulk material layer; removing the substrate from the bulk material layer and lapping the bottom surface of the bulk material until a bottom surface of the composite layer is exposed and is substantially parallel to the outer surface of the backing layer;
forming a second electrode layer on the bottom surface of the composite layer, patterning electrodes in the second electrode layer and providing an electrical connection for each electrode; and
connecting the second electrodes to an electrical device.

### Claim 14 (depends on 13)

The method of claim 13 where the bottom surface of the bulk material layer, the bottom surface of the composite layer, and the outer surface of the backing layer are within a thickness variation of 50 microns or less.

### Claim 15 (depends on 13)

The method of claim 13, further comprising the step of adding one or more matching layers adjacent to the second electrode layer.

### Claim 16 (depends on 13)

The method of claim 13, wherein patterning electrodes in the first electrode layer and the second electrode layer comprise forming kerfs between adjacent electrodes that extend into the composite layer, the kerfs being filled with a dielectric material.

### Claim 17 (depends on 16)

The method of claim 16, wherein the dielectric material is atmospheric air or an inert gas.

### Claim 18 (depends on 17)

The method of claim 17, wherein a backing layer is added adjacent to the first electrode layer or the second electrode layer such that air is trapped in the respective kerfs.

### Claim 19 (depends on 13)

The method of claim 13, further comprising the step of adding a shielding layer adjacent to the second electrode layer.

### Claim 20 (depends on 13)

The method of claim 13 where the method of forming electrodes, forming kerfs, or connection to an electrical device comprises a laser micromachining process.

### Claim 21

An ultrasonic transducer device, comprising:
an acoustic layer comprising a two-dimensional array of acoustically active elements;
a first electrode layer on a first side of the acoustic layer and a second electrode layer on a second side of the acoustic layer, the first electrode layer and the second electrode layer comprising non-parallel electrodes that permit each acoustically active element in the two-dimensional array to be separately addressable by a controller; and
a series of kerfs that separate adjacent acoustically active elements in the two-dimensional array of acoustically active elements of acoustically active elements, the series of kerfs being filled with a low dielectric, low acoustic impedance filler.