Double- and multi-membrane micromachined ultrasonic transducers.

Abstract

Provided herein are micromachined ultrasonic transducers, and imaging devices and assemblies comprising the micromachined ultrasonic transducers (MUTs). The MUTs described herein have multiple membranes to enhance acoustic output at higher frequencies.

Description

[Background technology]

[0001]

[0001] Ultrasound is a common imaging modality that has many applications in industrial, manufacturing, medical, and other settings. For example, a non-invasive imaging system for imaging and displaying images of internal organs in the human body transmits ultrasound signals into the body and receives signals reflected from the internal organs to capture images of those organs. Ultrasound also has applications outside of diagnostic imaging, such as ablation of tissue with high-intensity focused ultrasound (HIFU) or manipulation and modification of materials in manufacturing.

[0002]

[0002] Traditionally, ultrasound systems have used piezoelectric transducers (e.g., PZT transducers) to generate transmitted signals and / or receive reflected signals. Recently, there has been an increase in the use of smaller, more mass-producible transducers using MEMS (microelectromechanical systems) technology. Such MEMS ultrasound transducers include capacitive micromachined ultrasound transducers (cMUTs) and piezoelectric micromachined ultrasound transducers (pMUTs). While MEMS ultrasound transducers offer many advantages, improvements are still needed. Summary of the Invention [Means for solving the problem]

[0003]

[0003] The present disclosure relates to ultrasound systems, devices, and methods, and more particularly to ultrasound and methods using improved MEMS ultrasound transducers.

[0004] One aspect provided herein is a micromachined ultrasonic transducer (MUT) comprising: a substrate having a first resonant cavity and a second resonant cavity; a membrane coupled to at least a portion of the substrate, wherein a first portion of the membrane covers the first cavity and a second portion of the membrane covers the second cavity; a first electrode coupled to the first portion of the membrane; a secondary first electrode coupled to the first electrode; a second electrode coupled to the second portion of the membrane; and a secondary second electrode coupled to the second electrode.

[0004]

[0005] In some embodiments, the substrate further comprises a third resonant cavity, the membrane further comprises a third portion covering the third cavity, and the MUT further comprises a primary third electrode coupled to the third portion of the membrane and a secondary third electrode coupled to the primary third electrode. In some embodiments, the first cavity, the second cavity, the third cavity, or any combination thereof, has a circular, elliptical, semicircular, semielliptical, triangular, square, rectangular, hexagonal, or octagonal shape. In some embodiments, the first cavity and the third cavity have a circular shape. In some embodiments, the diameter of the first cavity is larger than the diameter of the third cavity. In some embodiments, the diameter of the first cavity is smaller than the diameter of the third cavity. In some embodiments, the diameters of the first cavity and the third cavity are equal. In some embodiments, the first cavity and the third cavity are asymmetric with respect to a light ray bisecting the first cavity. In some embodiments, the first cavity and the third cavity are symmetrical about a ray bisecting the first cavity. In some embodiments, the ratio of the distance between the ray bisecting the first cavity and the center of the second cavity to the diameter of the second cavity is about 1:0.3 to about 1:1. In some embodiments, the first cavity has a shape including a rounded primary distal portion having a primary diameter, a rounded secondary distal portion having a secondary diameter, and a mesial portion between the primary distal portion and the secondary distal portion. In some embodiments, the first cavity is symmetrical about a ray extending from a center point of the rounded primary distal portion to a center point of the rounded secondary distal portion, a ray bisecting the mesial portion, or both. In some embodiments, the ratio of the distance from the center of the rounded primary distal section to the center of the rounded secondary distal section to the diameter of the rounded primary distal section, the rounded secondary distal section, or both, is about 2:1 to about 5:1. In some embodiments, the ratio of the distance from the center of the rounded primary distal section to the center of the rounded secondary distal section to the minimum width of the mesial section is about 2:1 to about 7:1. In some embodiments, the ratio of the diameter of the rounded primary distal section, the rounded secondary distal section, or both, to the minimum width of the mesial section is about 1:1 to about 3:1.In some embodiments, the MUT further comprises one or more portions of a piezoelectric layer, wherein the secondary first electrode is coupled to the first electrode by a first portion of the one or more piezoelectric layer portions, the secondary second electrode is coupled to the second electrode by a second portion of the one or more piezoelectric layer portions, and the secondary third electrode is coupled to the third electrode by a third portion of the one or more piezoelectric layer portions, or any combination thereof. In some embodiments, the first electrode has a shape that is offset inwardly from the shape of the first cavity, the second electrode has a shape that is offset inwardly from the shape of the second cavity, and the third electrode has a shape that is offset inwardly from the shape of the third cavity, or any combination thereof. In some embodiments, the secondary first electrode has a shape that is offset inwardly from the shape of the first electrode, the secondary second electrode has a shape that is offset inwardly from the shape of the second electrode, and the secondary third electrode has a shape that is offset inwardly from the shape of the third electrode, or any combination thereof. In some embodiments, at least a portion of the membrane is formed of plastic, ceramic, or both. In some embodiments, at least a portion of the membrane is formed of ceramic, and the ceramic comprises silicon. In some embodiments, the plastic comprises silicon. In some embodiments, at least a portion of the membrane has a thickness of about 1 μm to about 10 μm. In some embodiments, the MUT has a higher acoustic output at a higher frequency than the same MUT without the second cavity, the second portion of the membrane covering the second cavity, the first second electrode, and the second second electrode (and / or without the third cavity, the third portion of the membrane covering the third cavity, the first third electrode, and the second third electrode). In some embodiments, the high frequency comprises an ultrasonic frequency of 5 MHz or greater.

[0005]

[0006] Another aspect provided herein is an imaging device comprising an array of the MUTs herein. In some embodiments, the array comprises a linear array, a polar array, or a polygonal array. In some embodiments, the substrates, membranes, or both of two or more adjacent MUTs in the array are contiguous. In some embodiments, the device further comprises an application specific integrated circuit (ASIC) coupled to the array of MUTs. In some embodiments, each MUT represents a single pixel of an ultrasound image acquired by the device. In some embodiments, the device further comprises one or more crosstalk reduction elements disposed between adjacent MUTs in the array. In some embodiments, the one or more crosstalk reduction elements comprise grooves, trenches, acoustically attenuating materials, or combinations thereof disposed between adjacent MUTs in the array.

[0006]

[0007] Another aspect provided herein is an imaging assembly comprising a component circuit, a memory, a communication unit, a signal processing circuit, an imaging subassembly comprising an acoustic absorbing layer, a control unit, an imaging device described herein, and a coating layer. In some embodiments, the imaging assembly further comprises a power source, a charging port, a display, or any combination thereof, electrically coupled to the component circuit, the memory, the communication unit, the signal processing unit, the imaging subassembly, or any combination thereof. In some embodiments, one or more of the component circuit, the memory, the communication unit, the signal processing unit, and the imaging subassembly are electrically coupled. In some embodiments, the acoustic absorbing layer is proximal to the control unit, the control unit is proximal to the imaging device, the imaging device is proximal to the coating layer, or any combination thereof. In some embodiments, the coating layer is distal to the imaging device, the imaging device is distal to the control unit, the control unit is distal to the acoustic absorbing layer, or any combination thereof. In some embodiments, the power source comprises a battery. In some embodiments, the control unit comprises an application specific integrated circuit (ASIC) coupled to the array of MUTs. In some embodiments, the coating layer comprises an acoustic lens.

[0007]

[0008] The novel features of the present disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1A]

[0009] FIG. 1 is a top view of an arrangement of first, second, and third membrane portions of an exemplary first primary micromachined ultrasonic transducer (MUT), according to one or more embodiments herein. [Figure 1B]

[0010] FIG. 1B is a top view of an arrangement of first, second, and third membrane portions of an exemplary second primary micromachined ultrasonic transducer (MUT) according to one or more embodiments herein. [Figure 2]

[0011] 1 is a cross-sectional side view of an exemplary MUT, according to one or more embodiments herein. [Figure 3]

[0012] FIG. 3A is a top-front-left perspective cross-sectional view of an exemplary MUT, according to one or more embodiments herein.

[0013] FIG. 3B is a perspective bottom-front left cross-sectional view of an exemplary MUT, according to one or more embodiments herein. [Figure 4]

[0014] FIG. 1 is a top view of an exemplary imaging device in accordance with one or more embodiments of the present disclosure. [Figure 5A]

[0015] FIG. 10 is a top view of a secondary arrangement of first, second, and third membrane portions of an exemplary second MUT according to one or more embodiments herein. [Figure 5B]

[0016] FIG. 10 is a top view of a tertiary arrangement of first, second, and third membrane portions of an exemplary third MUT according to one or more embodiments herein. [Figure 5C]

[0017] FIG. 1B is a top view of a quaternary arrangement of first, second, and third membrane portions of an exemplary MUT, according to one or more embodiments herein. [Figure 5D]

[0018] FIG. 1B is a top view of a quinary arrangement of first, second, and third membrane portions of an exemplary MUT, according to one or more embodiments herein. [Figure 6]

[0019] FIG. 1 illustrates an exemplary imaging assembly in accordance with one or more embodiments herein. [Figure 7]

[0020] 10 is a graph illustrating the relationship between frequency and acoustic power for a MUT with and without second and third membrane portions in accordance with one or more embodiments herein. [Figure 8A]

[0021] 10 is a graph comparing directivity at 2 MHz with and without crosstalk reduction elements in accordance with one or more embodiments herein. [Figure 8B]

[0022] 10 is a graph comparing directivity at 3 MHz with and without crosstalk reduction elements in accordance with one or more embodiments herein. [Figure 8C]

[0023] 10 is a graph comparing directivity at 4 MHz with and without crosstalk reduction elements in accordance with one or more embodiments herein. [Figure 8D]

[0024] 10 is a graph comparing directivity at 5 MHz with and without crosstalk reduction elements in accordance with one or more embodiments herein. DETAILED DESCRIPTION OF THE INVENTION

[0009]

[0025] Provided herein are imaging components and devices having micromachined ultrasound transducers (MUTs). Micromachined Ultrasonic Transducers

[0026] 1A , one aspect provided herein is a micromachined ultrasonic transducer (MUT) 1000. As shown, in some embodiments, the MUT 1000 comprises a substrate 100, a membrane 500, a primary first electrode 120, a secondary first electrode 130, a primary second electrode 220, and a secondary second electrode 230. In some embodiments, the substrate 100 comprises a semiconductor material, such as silicon and / or silicon dioxide. In some embodiments, the MUT 1000 is a pMUT. In some embodiments, the MUT 1000 is a cMUT.

[0010]

[0027] In some embodiments, the substrate 100 has a first resonant cavity 110 and a second resonant cavity 210. In some embodiments, according to Figure 1B, the substrate 100 further comprises a third resonant cavity 310. In some embodiments, the substrate 100 comprises the first resonant cavity 110 and the second resonant cavity 210, but does not include the third resonant cavity 310.

[0011]

[0028] In some embodiments, the membrane 500 is bonded to at least a portion of the substrate 100. As shown, a first portion 150 of the membrane 500 covers the first cavity 110, and a second portion 250 of the membrane 500 covers the second cavity 210. As shown, in some embodiments, the membrane 500 further comprises a third portion 350 that covers the third cavity 310.

[0012]

[0029] In some embodiments, the primary first electrode 120 (bottom) is coupled to the first portion 150 of the membrane 500, and the secondary first electrode 130 (top) is coupled to the primary first electrode 120. In some embodiments, the primary second electrode 220 (bottom) is coupled to the second portion 250 of the membrane 500, and the secondary second electrode 230 (top) is coupled to the primary second electrode 220. In some embodiments, according to FIG. 1B , the MUT 1000 further comprises a primary third electrode 320 (bottom) coupled to the third portion 250 of the membrane 500, and a secondary third electrode 330 (top) coupled to the primary third electrode 320.

[0013]

[0030] In some embodiments, according to FIG. 1B , the first cavity 110, the second cavity 210, the third cavity 310, or any combination thereof has a polygonal shape. In some embodiments, the first cavity 110, the second cavity 210, the third cavity 310, or any combination thereof has a circular, elliptical, semicircular, semielliptical, triangular, square, hexagonal, rectangular, octagonal, or other polygonal shape. In some embodiments, the first cavity 110, the second cavity 210, the third cavity 310, or any combination thereof has a closed shape. In some embodiments, the first cavity 110, the second cavity 210, the third cavity 310, or any combination thereof has a shape with one or more straight edges, one or more curved edges, or both. In some embodiments, the first cavity 110 and the third cavity 310 have a circular shape. In some embodiments, the shape of the first cavity 110, the second cavity 210, the third cavity 310, or any combination thereof is defined as the shape of the distal end or the proximal end. In some embodiments, the electrodes 120 and 130, 220 and 230, and 320 and 330 disposed on the cavities 110, 210, 310, respectively, have shapes corresponding to the cavities 110, 210, 310, e.g., with the electrodes 120, 130, 220, 230, 320, 330, as shown in FIG. 1A . In some embodiments, (i) the first cavity 110 and the secondary first electrode 130 (top) have a cross-sectional shape like a snowboard (i.e., a rectangle with enlarged curved ends), and (ii) the second cavity 210 and the secondary second electrode 230 (top) and (iii) the third cavity 310 and the secondary third electrode 330 (top) have the shape of a circle positioned on either side of (i) the first cavity 110 and the secondary first electrode 130 (top). In some embodiments, the snowboard shape of the first cavity 110 can improve the acoustic output and directionality of the MUT 1000 herein.

[0014]

[0031] In some embodiments, the diameter 211 of the second cavity 210 is larger than the diameter 311 of the third cavity 310. In some embodiments, the diameter 211 of the second cavity 210 is smaller than the diameter 311 of the third cavity 310. In some embodiments, the diameter 211 of the second cavity 210 is equal to the diameter 311 of the third cavity 310. In some embodiments, according to the exemplary MUT shown in FIG. 5B , the second cavity 210 and the third cavity 310 are asymmetric about the light ray 115 that bisects the first cavity 110. In some embodiments, according to the exemplary first and second MUTs shown in FIGS. 1A and 5A , respectively, the second cavity 210 and the third cavity 310 are symmetric about the light ray 115 that bisects the first cavity 110. In some embodiments, the shape and orientation of the electrodes 120, 130, 220, 230, 320, 330 disposed on the cavities 110, 210, 310 can improve the acoustic output and directionality of the MUT 1000 herein.

[0015]

[0032] In some embodiments, the ratio of the distance 212 between the beam 115 bisecting the first cavity 110 and the center of the second cavity 210 to the diameter 211 of the second cavity 210 is about 1:1 to about 3:1. In some embodiments, the ratio of the distance 212 between the beam 115 bisecting the first cavity 110 and the center of the second cavity 210 to the diameter 211 of the second cavity 210 is about 1:1 to about 1.25:1, about 1:1 to about 1.5:1, about 1:1 to about 1.75:1, about 1:1 to about 2:1, about 1:1 to about 2.25:1, or about 1:1 to about 2.5:1. 1, about 1:1 to about 2.75:1, about 1:1 to about 3:1, about 1.25:1 to about 1.5:1, about 1.25:1 to about 1.75:1, about 1.25:1 to about 2:1, about 1.25:1 to about 2.25:1, about 1.25:1 to about 2.5:1, about 1.25:1 to about 2.75:1, about 1.25:1 to about 3:1, about 1.5:1 to about 1.75:1, about 1.5:1 to about 2:1, about 1.5:1 to about 2.25:1, about 1.5:1 to about 2.5:1, about 1.5:1 to about 2.75:1, about 1.5:1 to about 3:1, about 1.75:1 to about 2:1, about 1.75:1 to about 2.25:1, about 1.75:1 to about 2.5:1, about 1.75:1 to about 2.75:1, about 1.75:1 to about 3:1, about 2: 1 to about 2.25:1, about 2:1 to about 2.5:1, about 2:1 to about 2.75:1, about 2:1 to about 3:1, about 2.25:1 to about 2.5:1, about 2.25:1 to about 2.75:1, about 2.25:1 to about 3:1, about 2.5:1 to about 2.75:1, about 2.5:1 to about 3:1, or about 2.75:1 to about 3:1, including increments therein. In some embodiments, the ratio of the distance 212 between the light beam 115 bisecting the first cavity 110 and the center of the second cavity 210 to the diameter 211 of the second cavity 210 is about 1:1, about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, about 2.75:1, or about 3:1. In some embodiments, the ratio of the distance 212 between the light beam 115 bisecting the first cavity 110 and the center of the second cavity 210 to the diameter 211 of the second cavity 210 is at least about 1:1, about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, or about 2.75:1.In some embodiments, the ratio of the distance 212 between the light beam 115 bisecting the first cavity 110 and the center of the second cavity 210 to the diameter 211 of the second cavity 210 is at most about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, about 2.75:1, or about 3:1.

[0016]

[0033] In some embodiments, the ratio of the distance 312 between the light beam 115 bisecting the first cavity 110 and the center of the third cavity 310 to the diameter 311 of the third cavity 310 is about 1:1 to about 3:1. In some embodiments, the ratio of the distance 312 between the light beam 115 bisecting the first cavity 110 and the center of the third cavity 310 to the diameter 311 of the third cavity 310 is about 1:1 to about 1.25:1, about 1:1 to about 1.5:1, about 1:1 to about 1.75:1, about 1:1 to about 2:1, about 1:1 to about 2.25:1, or about 1:1 to about 2.5:1. 1, about 1:1 to about 2.75:1, about 1:1 to about 3:1, about 1.25:1 to about 1.5:1, about 1.25:1 to about 1.75:1, about 1.25:1 to about 2:1, about 1.25:1 to about 2.25:1, about 1.25:1 to about 2.5:1, about 1.25:1 to about 2.75:1, about 1.25:1 to about 3:1, about 1.5:1 to about 1.75:1, about 1.5:1 to about 2:1, about 1.5:1 to about 2.25:1, about 1.5:1 to about 2.5:1, about 1.5:1 to about 2.75:1, about 1.5:1 to about 3:1, about 1.75:1 to about 2:1, about 1.75:1 to about 2.25:1, about 1.75:1 to about 2.5:1, about 1.75:1 to about 2.75:1, about 1.75:1 to about 3:1, about 2: 1 to about 2.25:1, about 2:1 to about 2.5:1, about 2:1 to about 2.75:1, about 2:1 to about 3:1, about 2.25:1 to about 2.5:1, about 2.25:1 to about 2.75:1, about 2.25:1 to about 3:1, about 2.5:1 to about 2.75:1, about 2.5:1 to about 3:1, or about 2.75:1 to about 3:1, including increments therein. In some embodiments, the ratio of the distance 312 between the light beam 115 bisecting the first cavity 110 and the center of the third cavity 310 to the diameter 311 of the third cavity 310 is about 1:1, about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, about 2.75:1, or about 3:1. In some embodiments, the ratio of the distance 312 between the light beam 115 bisecting the first cavity 110 and the center of the third cavity 310 to the diameter 311 of the third cavity 310 is at least about 1:1, about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, or about 2.75:1.In some embodiments, the ratio of the distance 312 between the light beam 115 bisecting the first cavity 110 and the center of the third cavity 310 to the diameter 311 of the third cavity 310 is at most about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, about 2.75:1, or about 3:1. In some embodiments, the dimensions and ratios of the electrodes 120 and 130, 220 and 230, and 320 and 330 disposed on the cavities 110, 210, and 310, respectively, can improve the acoustic output and directionality of the MUT 1000 herein.

[0017]

[0034] 1 , in the primary example of the MUT 1000, the first cavity 110 and the complementary electrodes 120, 130 have a shape comprising a rounded primary distal portion 110A having a primary diameter 111, a rounded secondary distal portion 110C having a secondary diameter 112, and a mesial portion 110B between the primary distal portion 110A and the secondary distal portion 110C. In some embodiments, the first cavity 110 and the complementary electrodes 120, 130 are symmetrical about a ray 116 extending from a center point of the rounded primary distal portion 110A to a center point of the rounded secondary distal portion 110C. In some embodiments, the first cavity 110 and the complementary electrodes 120, 130 are symmetrical about a ray 116 that bisects the mesial portion 110B. In some embodiments, the first cavity 110 and complementary electrodes 120, 130 are asymmetric about a ray 115 that extends from a center point of the rounded primary distal portion 110A to a center point of the rounded secondary distal portion 110C. In some embodiments, the first cavity 110 and complementary electrodes 120, 130 are asymmetric with respect to a ray 116 that bisects the mesial portion 110B. In some embodiments, the first cavity 110 and complementary electrodes 120, 130 are symmetric about an axial ray 115 that is perpendicular to the ray 116 that bisects the mesial portion 110B.

[0018]

[0035] In some embodiments, the ratio of the distance 113 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, is between about 3:1 and about 5:1. In some embodiments, the ratio of the distance 113 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, is between about 3:1 and about 3.25:1, between about 3:1 and about 3.5:1, between about 3:1 and about 3.75:1, or between about 3:1 and about 3.5:1. 3:1 to about 4:1, about 3:1 to about 4.25:1, about 3:1 to about 4.5:1, about 3:1 to about 4.75:1, about 3:1 to about 5:1, about 3.25:1 to about 3.5:1, about 3.25:1 to about 3.75:1, about 3.25:1 to about 4:1, about 3.25:1 to about 4.25:1, about 3.25:1 to about 4.5:1, about 3.25:1 to about 4.75:1, about 3.25:1 to about 5:1, about 3.5:1 to about 3.75:1, about 3.5:1 to about 4:1, about 3.5:1 to about 4.25:1, about 3.5:1 to about 4.5:1, about 3.5:1 to about 4.75:1, about 3.5:1 to about 5:1, about 3.75:1 to about 4:1, about 3.75:1 to about 4.25:1, about 3.75:1 to about 4.5:1, about 3.75:1 to about 4.75:1, about 3.75: 1 to about 5:1, about 4:1 to about 4.25:1, about 4:1 to about 4.5:1, about 4:1 to about 4.75:1, about 4:1 to about 5:1, about 4.25:1 to about 4.5:1, about 4.25:1 to about 4.75:1, about 4.25:1 to about 5:1, about 4.5:1 to about 4.75:1, about 4.5:1 to about 5:1, or about 4.75:1 to about 5:1, including increments therein. In some embodiments, the ratio of the distance 113 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, is about 3:1, about 3.25:1, about 3.5:1, about 3.75:1, about 4:1, about 4.25:1, about 4.5:1, about 4.75:1, or about 5:1.In some embodiments, the ratio of the distance 113 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, is at least about 3:1, about 3.25:1, about 3.5:1, about 3.75:1, about 4:1, about 4.25:1, about 4.5:1, or about 4.75:1. In some embodiments, the ratio of the distance 113 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, is at most about 3.25:1, about 3.5:1, about 3.75:1, about 4:1, about 4.25:1, about 4.5:1, about 4.75:1, or about 5:1.

[0019]

[0036] In some embodiments, the ratio of distance 114 from the center of rounded primary distal portion 110A to the center of rounded secondary distal portion 110C to minimum width 113 of mesial portion 110B is about 2:1 to about 7:1. In some embodiments, the ratio of distance 114 from the center of rounded primary distal portion 110A to the center of rounded secondary distal portion 110C to minimum width 113 of mesial portion 110B is about 2:1 to about 2.5:1, about 2:1 to about 3:1, about 2:1 to about 3.5:1, about 2:1 to about 4:1, about 2:1 to about 4.5:1, about 2:1 to about 5:1, about 2:1 to about 5.5:1, about 2:1 to about 6:1, about 2:1 to about 6.5:1, about 2:1 to about 7:1. 1, about 2.5:1 to about 3:1, about 2.5:1 to about 3.5:1, about 2.5:1 to about 4:1, about 2.5:1 to about 4.5:1, about 2.5:1 to about 5:1, about 2.5:1 to about 5.5:1, about 2.5:1 to about 6:1, about 2.5:1 to about 6.5:1, about 2.5:1 to about 7:1, about 3:1 to about 3.5:1, about 3:1 to about 4:1, about 3:1 to about 4.5:1, about 3:1 to about 5:1, about 3:1 to about 5.5:1, about 3:1 to about 6:1, about 3 :1 to about 6.5:1, about 3:1 to about 7:1, about 3.5:1 to about 4:1, about 3.5:1 to about 4.5:1, about 3.5:1 to about 5:1, about 3.5:1 to about 5.5:1, about 3.5:1 to about 6:1, about 3.5:1 to about 6.5:1, about 3.5:1 to about 7:1, about 4:1 to about 4.5:1, about 4:1 to about 5:1, about 4:1 to about 5.5:1, about 4:1 to about 6:1, about 4:1 to about 6.5:1, about 4:1 to about 7:1, about 4.5:1 to about 5: 1, about 4.5:1 to about 5.5:1, about 4.5:1 to about 6:1, about 4.5:1 to about 6.5:1, about 4.5:1 to about 7:1, about 5:1 to about 5.5:1, about 5:1 to about 6:1, about 5:1 to about 6.5:1, about 5:1 to about 7:1, about 5.5:1 to about 6:1, about 5.5:1 to about 6.5:1, about 5.5:1 to about 7:1, about 6:1 to about 6.5:1, about 6:1 to about 7:1, or about 6.5:1 to about 7:1, including increments therein. In some embodiments, the ratio of the distance 114 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the minimum width 113 of the mesial portion 110B is about 2:1, about 2.5:1, about 3:1, about 3.5:1, about 4:1, about 4.5:1, about 5:1, about 5.5:1, about 6:1, about 6.5:1, or about 7:1.In some embodiments, the ratio of the distance 114 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the minimum width 113 of the mesial portion 110B is at least about 2:1, about 2.5:1, about 3:1, about 3.5:1, about 4:1, about 4.5:1, about 5:1, about 5.5:1, about 6:1, or about 6.5:1. In some embodiments, the ratio of the distance 114 from the center of the rounded primary distal portion 110A to the center of the rounded secondary distal portion 110C to the minimum width 113 of the mesial portion 110B is at most about 2.5:1, about 3:1, about 3.5:1, about 4:1, about 4.5:1, about 5:1, about 5.5:1, about 6:1, about 6.5:1, or about 7:1.

[0020]

[0037] In some embodiments, the ratio of the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, to the minimum width 113 of the mesial portion 110B is 3:1. In some embodiments, the ratio of the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, to the minimum width 113 of the mesial portion 110B is about 1:1 to about 1.25:1, about 1:1 to about 1.5:1, about 1:1 to about 1.75:1, about 1:1 to about 2:1, about 1:1 to about 2.25:1, about 1:1 to about 2. ... :1 to about 2.5:1, about 1:1 to about 2.75:1, about 1:1 to about 3:1, about 1.25:1 to about 1.5:1, about 1.25:1 to about 1.75:1, about 1.25:1 to about 2:1, about 1.25:1 to about 2.25:1, about 1.25:1 to about 2.5:1, about 1.25:1 to about 2.75:1, about 1.25:1 to about 3:1, about 1.5:1 to about 1. 75:1, about 1.5:1 to about 2:1, about 1.5:1 to about 2.25:1, about 1.5:1 to about 2.5:1, about 1.5:1 to about 2.75:1, about 1.5:1 to about 3:1, about 1.75:1 to about 2:1, about 1.75:1 to about 2.25:1, about 1.75:1 to about 2.5:1, about 1.75:1 to about 2.75:1, about 1.75:1 to about 3:1, about 2:1 to about 2.25:1, about 2:1 to about 2.5:1, about 2:1 to about 2.75:1, about 2:1 to about 3:1, about 2.25:1 to about 2.5:1, about 2.25:1 to about 2.75:1, about 2.25:1 to about 3:1, about 2.5:1 to about 2.75:1, about 2.5:1 to about 3:1, or about 2.75:1 to about 3:1, including increments therein. In some embodiments, the ratio of the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, to the minimum width 113 of the mesial portion 110B is about 1:1, about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, about 2.75:1, or about 3:1. In some embodiments, the ratio of the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, to the minimum width 113 of the mesial portion 110B is at least about 1:1, about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, or about 2.75:1.In some embodiments, the ratio of the diameter 111 of the rounded primary distal portion 110A, the diameter 112 of the rounded secondary distal portion 110C, or both, to the minimum width 113 of the mesial portion 110B is at most about 1.25:1, about 1.5:1, about 1.75:1, about 2:1, about 2.25:1, about 2.5:1, about 2.75:1, or about 3:1.

[0021]

[0038] In some embodiments, according to FIG. 1, the center points of the second cavity 210 and the third cavity 310 coincide with the ray 115 that bisects the first cavity 110. In some embodiments, according to FIG. 5A, the MUT 1000A is similar to the MUT 1000, and the center points of the second cavity 210 and the third cavity 310 coincide with the center point of the primary diameter 111 of the first cavity 110. In some embodiments, according to FIG. 5B, the MUT 1000B is similar to the MUT 1000, and the second cavity 210 and the third cavity 310 are located on the same side of the first cavity 110, and the ray connecting the center of the second cavity 210 and the center of the third cavity 310 is parallel to the vertical ray 115. FIGS. 5C-5D are top views of additional exemplary arrangements of the first, second, and third membrane portions of the MUTs 1000C and 1000B. In Figure 5C, the second cavity 210 and third cavity 310 of the MUT 1000C are positioned on opposite sides of the vertical ray 115, but are not symmetrical about an axis perpendicular to the vertical ray 115. As shown, in some embodiments, the vertical ray 115 of one MUT 1000C bisects the second cavity 420 of another MUT 1000C below it. In Figure 5C, unlike the parallelogram arrangement of Figure 5A, the arrangement may also be an offset triangular arrangement.

[0022]

[0039] In some embodiments, the MUT 1000 further comprises one or more portions of a piezoelectric layer 600. In some embodiments, the MUT 1000 is a piezoelectric micromachined ultrasonic transducer (pMUT). In some embodiments, according to FIG. 2, the secondary first electrode 130 (top) is coupled to the primary electrode 120 (bottom) by a first portion of one or more piezoelectric layer 600 portions. Further, in some embodiments, the secondary second electrode 230 (top) is coupled to the primary electrode 220 (bottom) by a second portion of one or more piezoelectric layer 600 portions, the secondary third electrode 330 (top) is coupled to the primary electrode 320 (bottom) by a third portion of one or more piezoelectric layer 600 portions, or any combination thereof. In some embodiments, the piezoelectric layer comprises at least one of PZT, PZT-N, PMN-Pt, AlN, Sc-AlN, ZnO, PVDF, and LiNiO.

[0023]

[0040] In some embodiments, the first electrode 120 has a shape that is offset inwardly from the shape of the first cavity 110. In some embodiments, the second electrode 220 has a shape that is offset inwardly from the shape of the second cavity 210. In some embodiments, the third electrode 320 has a shape that is offset inwardly from the shape of the third cavity 310. In some embodiments, the secondary first electrode 130 has a shape that is offset inwardly from the shape of the first electrode 120. In some embodiments, the secondary second electrode 230 has a shape that is offset inwardly from the shape of the second electrode 220. In some embodiments, the secondary third electrode 330 has a shape that is offset inwardly from the shape of the third electrode 320.

[0024]

[0041] In some embodiments, the offset between the primary electrode 120 and the first cavity 110 is equal to the offset between the primary electrode 120 and the secondary first electrode 130. In some embodiments, the offset between the primary electrode 120 and the first cavity 110 is greater than the offset between the primary electrode 120 and the secondary first electrode 130. In some embodiments, the offset between the primary electrode 120 and the first cavity 110 is less than the offset between the primary electrode 120 and the secondary first electrode 130.

[0025]

[0042] In some embodiments, the offset between the primary second electrode 220 and the second cavity 210 is equal to the offset between the primary second electrode 220 and the secondary second electrode 230. In some embodiments, the offset between the primary second electrode 220 and the second cavity 210 is greater than the offset between the primary second electrode 220 and the secondary second electrode 230. In some embodiments, the offset between the primary second electrode 220 and the second cavity 210 is less than the offset between the primary second electrode 220 and the secondary second electrode 230.

[0026]

[0043] In some embodiments, the offset between the primary third electrode 320 and the third cavity 310 is equal to the offset between the primary third electrode 320 and the secondary third electrode. In some embodiments, the offset between the primary third electrode 320 and the third cavity 310 is greater than the offset between the primary third electrode 320 and the secondary third electrode. In some embodiments, the offset between the primary third electrode 320 and the third cavity 310 is less than the offset between the primary third electrode 320 and the secondary third electrode.

[0027]

[0044] In some embodiments, secondary first electrode 130 is coupled to primary electrode 120 by piezoelectric layer 400. In some embodiments, secondary second electrode 230 is coupled to primary electrode 220 by piezoelectric layer 400. In some embodiments, secondary third electrode 330 is coupled to primary electrode 320 by piezoelectric layer 400. In some embodiments, at least a portion of membrane 500 is formed from plastic. In some embodiments, the plastic comprises silicon. In some embodiments, at least a portion of membrane 500 is formed from silicon and / or silicon dioxide.

[0028]

[0045] In some embodiments, the first electrode 120 has a shape that is offset inward from the shape of the first cavity 110. In some embodiments, the second electrode 220 has a shape that is offset inward from the shape of the second cavity 210. In some embodiments, the third electrode 320 has a shape that is offset inward from the shape of the third cavity 310. In some embodiments, the secondary first electrode 130 has a shape that is offset inward from the shape of the first electrode 120. In some embodiments, the secondary second electrode 230 has a shape that is offset inward from the shape of the second electrode 220. In some embodiments, the secondary third electrode 330 has a shape that is offset inward from the shape of the third electrode 320. In some embodiments, the offset between the first cavity 110 and the first electrode 120 is equal to the offset between the secondary first electrode 130 and the first electrode 120. In some embodiments, the offset between the first cavity 110 and the first electrode 120 is greater than the offset between the secondary first electrode 130 and the first electrode 120. In some embodiments, the offset between the first cavity 110 and the first electrode 120 is less than the offset between the secondary first electrode 130 and the first electrode 120. In some embodiments, the offset between the second cavity 210 and the second electrode 220 is equal to the offset between the second electrode 220 and the secondary second electrode 230. In some embodiments, the offset between the second cavity 210 and the second electrode 220 is greater than the offset between the second electrode 220 and the secondary second electrode 230. In some embodiments, the offset between the second cavity 210 and the second electrode 220 is less than the offset between the second electrode 220 and the secondary second electrode 230. In some embodiments, the offset between the third cavity 310 and the primary third electrode 320 is equal to the offset between the primary third electrode 320 and the secondary third electrode. In some embodiments, the offset between the third cavity 310 and the primary third electrode 320 is greater than the offset between the primary third electrode 320 and the secondary third electrode.In some embodiments, the offset between the third cavity 310 and the primary third electrode 320 is less than the offset between the primary third electrode 320 and the secondary third electrode.

[0029]

[0046] In some embodiments, at least a portion of membrane 500 has a thickness of about 1 μm to about 10 μm. In some embodiments, at least a portion of membrane 500 has a thickness of about 1 μm to about 2 μm, about 1 μm to about 3 μm, about 1 μm to about 4 μm, about 1 μm to about 5 μm, about 1 μm to about 6 μm, about 1 μm to about 7 μm, about 1 μm to about 8 μm, about 1 μm to about 9 μm, about 1 μm to about 10 μm, about 2 μm to about 3 μm, about 2 μm to about 4 μm, about 2 μm to about 5 μm, about 2 μm to about 6 μm, about 2 μm to about 7 μm, about 2 μm to about 8 μm, about 2 μm to about 9 μm, about 2 μm to about 10 μm, about 3 μm to about 4 μm, about 3 μm to about 5 μm, about 3 μm to about 6 μm, about 3 μm to about 7 μm, about 3 μm to about 8 μm, about 3 μm to about 3 μm. to about 9 μm, about 3 μm to about 10 μm, about 4 μm to about 5 μm, about 4 μm to about 6 μm, about 4 μm to about 7 μm, about 4 μm to about 8 μm, about 4 μm to about 9 μm, about 4 μm to about 10 μm, about 5 μm to about 6 μm, about 5 μm to about 7 μm, about 5 μm to about 8 μm, about 5 μm to about 9 μm, about 5 μm to about 10 μm, about 6 μm to about 7 μm, about 6 μm to about 8 μm, about 6 μm to about 9 μm, about 6 μm to about 10 μm, about 7 μm to about 8 μm, about 7 μm to about 9 μm, about 7 μm to about 10 μm, about 8 μm to about 9 μm, about 8 μm to about 10 μm, or about 9 μm to about 10 μm, including increments therein. In some embodiments, at least a portion of the membrane 500 has a thickness of about 1 μm, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, or about 10 μm. In some embodiments, at least a portion of the membrane 500 has a thickness of at least about 1 μm, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, or about 9 μm. In some embodiments, at least a portion of the membrane 500 has a thickness of at most about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, or about 10 μm. MUT array

[0047] Another aspect provided herein is an array 4000 of MUTs 1000, according to FIG. 4. As shown, the array 4000 comprises a diamond-shaped array of MUTs 1000. In some embodiments, the array comprises a linear array. In some embodiments, the array comprises a polar array. In some embodiments, the array comprises a polygonal array. In some embodiments, the polygonal array 4000 comprises a triangular array, a pentagonal array, a parallelogram array, a diamond array, a hexagonal array, or an octagonal array.

[0030]

[0048] In some embodiments, the substrates of two or more adjacent MUTs 1000 in the array 4000 are contiguous. In some embodiments, the membranes of two or more adjacent MUTs 1000 in the array 4000 are contiguous. In some embodiments, one or more crosstalk reduction elements 40 are disposed between adjacent MUTs 1000. In some embodiments, one or more crosstalk reduction elements 40 are disposed at the edge of each MUT 1000. In some embodiments, one or more crosstalk elements 40 comprise one or more grooves, trenches, etc. formed in the substrate of the MUT 1000 and / or acoustic damping material disposed within and / or on the surface of the substrate 100 and / or diaphragm 500.

[0031]

[0049] As described herein, the MUTs 1000 in the MUT array 4000 described herein are pMUTs. Alternatively, or in combination, one or more of the MUTs 1000 in the MUT array 4000 are capacitive micromachined ultrasonic transducers (cMUTs). The MUT cavities described herein are sandwiched between an associated pair of electrodes, with one electrode of the pair coupled to a membrane or portion of a membrane. Optionally, a resonant cavity can be connected to the cMUT. Imaging Assembly

[0050] Another aspect provided herein is imaging assembly 5000, according to FIG. 6 . As shown, imaging assembly 5000 includes component circuitry 630, memory 640, communication unit 650 (e.g., for receiving and / or transmitting signals from the outside), signal processing circuitry 670, and imaging subassembly 700. In some embodiments, component circuitry 630 includes an input / output (IO) bus. In some embodiments, imaging subassembly 700 includes acoustic absorbing layer 730, control unit 720, imaging array 1001, and coating layer 710, as shown. In some embodiments, imaging array 1001 includes an array of MUTs as described herein. In some embodiments, control unit 720 includes an application specific integrated circuit (ASIC) coupled to imaging array 1001. In some embodiments, the ASIC is configured to individually address each MUT in the imaging array 1001, each MUT comprising a first cavity and complementary electrode pair and at least one second cavity and complementary electrode pair as described herein. In some embodiments, the ASIC is configured to digitize the analog receive signals of each MUT in the imaging array 1001. In some embodiments, the ultrasound signal transmitted and received from each MUT corresponds to a single pixel in an ultrasound image processed by the ASIC. In some embodiments, the ultrasound signals received from multiple MUTs are combined into a single pixel.

[0032]

[0051] In some embodiments, imaging assembly 5000 further comprises a power source 620, such as a battery (primary and / or rechargeable), a charging port 610, a display 660, or any combination thereof, electrically coupled to component circuitry 630, memory 640, communication unit 650, signal processing unit 670, imaging subassembly 700, or any combination thereof. In some embodiments, one or more of component circuitry 630, memory 640, communication unit 650, signal processing unit 670, and imaging subassembly 700 are electrically coupled. In some embodiments, acoustic absorbing layer 730 is proximate to control unit 720, which is proximate to imaging array 1001, which is proximate to coating layer 710, or any combination thereof. In some embodiments, acoustic absorbing layer 730 is proximate to imaging device 1001, and control unit 720 is located proximate to absorbing layer 730. In some embodiments, the coating layer 710 is distal to the imaging device 1000, the imaging device 1000 is distal to the control unit 720, the control unit 720 is distal to the acoustic absorbing layer 730, or any combination thereof. In some embodiments, the coating layer 710 comprises an acoustic lens and / or a matching layer. MUT Performance

[0052] An array of MUTs according to one or more embodiments described herein has been modeled. FIG. 7 is a graph illustrating frequency versus acoustic power for MUTs with and without additional membranes and resonant cavities. For example, the graph compares MUT 1000 with a similar MUT that includes only a membrane, piezoelectric layer, and electrode components associated with a central resonant cavity 110. As shown, the inclusion of the additional membrane and resonant cavities shifted the peak frequency from about 5 MHz to about 7 MHz and increased the peak acoustic power by about 3 dB. The additional membrane and resonant cavities of the MUT result in a stronger frequency response at higher frequencies (e.g., >5 MHz).

[0033]

[0053] A model was also performed to evaluate MUTs with and without crosstalk reduction elements (CTREs) according to one or more embodiments described herein. FIG. 8A is a graph comparing directivity at 2 MHz with and without a crosstalk reduction element. FIG. 8B is a graph comparing directivity at 3 MHz with and without a CTRE. FIG. 8C is a graph comparing directivity at 4 MHz with and without a CTRE. FIG. 8D is a graph comparing directivity at 5 MHz with and without a CTRE. As shown, the use of a CTRE (e.g., a CTRE described herein) can improve the directivity of the exemplary MUT array over a wide frequency range. Notably, the inclusion of a CTRE flattens the directivity curve at various angles. Terms and Definitions

[0054] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0034]

[0055] As used herein, the singular forms "a," "an," and "the" include the plural forms as well, unless the context clearly dictates otherwise. References herein to "or" are intended to include "and / or" as well, unless expressly stated otherwise.

[0035]

[0056] As used herein, the term "about" refers, in some cases, to an amount approximately equal to the stated amount.

[0057] As used herein, the term "about" refers to an amount near 10%, 5%, or 1% of the stated amount, including increments therein.

[0036]

[0058] As used herein, the term "about" when used in reference to a percentage refers to an amount that is 10%, 5%, or 1% more or less than the stated percentage, including increments therein.

[0037]

[0059] As used herein, the terms "at least one," "one or more," and "and / or" are open-ended expressions that function as both conjunctions and disjunctions. For example, the phrases "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or C," and "A, B, and / or C" each mean A only, B only, C only, A and B in combination, A and C in combination, B and C in combination, or A, B, and C in combination.

[0038]

[0060] As used herein, the term "mesial" refers to the portion between two or more distal portions, or toward the geometric center of an object.

[0061] While preferred embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the present disclosure. It is to be understood that various alternatives to the embodiments of the present disclosure described herein may be used in practicing the present disclosure.

Claims

1. (a) a substrate having a first resonant cavity and a second resonant cavity; (b) a membrane bonded to at least a portion of the substrate, (i) a first portion of the membrane covering the first cavity; (ii) a membrane, a second portion of the membrane covering the second cavity; (c) a single electrode coupled to the first portion of the membrane; (d) a secondary first electrode coupled to the primary first electrode; (e) a second electrode coupled to the second portion of the membrane; (f) a secondary second electrode coupled to the primary second electrode; and A micromachined ultrasonic transducer (MUT) comprising:

2. (a) the substrate further comprises a third resonant cavity; (b) the membrane further comprises a third portion covering the third cavity; 10. The MUT of claim 1, wherein (c) the MUT further comprises a primary third electrode coupled to the third portion of the membrane and a secondary third electrode coupled to the primary third electrode.

3. The MUT of claim 2 , wherein the first cavity, the second cavity, the third cavity, or any combination thereof has a circular, elliptical, semicircular, semielliptical, triangular, square, rectangular, hexagonal, or octagonal shape.

4. The MUT of claim 3 , wherein the second cavity and the third cavity have a circular shape.

5. The MUT of claim 4 , wherein the diameter of the second cavity is greater than the diameter of the third cavity.

6. The MUT of claim 4 , wherein the diameter of the second cavity is smaller than the diameter of the third cavity.

7. The MUT of claim 4 , wherein the second cavity and the third cavity have equal diameters.

8. The MUT of claim 4 , wherein the second cavity and the third cavity are asymmetric with respect to a ray that bisects the first cavity.

9. The MUT of claim 4 , wherein the second cavity and the third cavity are symmetrical with respect to a ray that bisects the first cavity.

10. 10. The MUT of claim 9, wherein a ratio of a distance between the light ray bisecting the first cavity and a center of the second cavity to the diameter of the second cavity is from about 1:0.3 to about 1:

1.

11. The first cavity comprises: (a) a rounded primary distal portion having a primary diameter; (b) a rounded secondary distal portion having a secondary diameter; (c) a mesial portion between the primary distal portion and the secondary distal portion; The MUT of claim 1 having a shape comprising:

12. The first cavity comprises: (a) a ray extending from a center point of the rounded primary distal portion to a center point of the rounded secondary distal portion; (b) a ray bisecting the mesial portion; or (c) Both The MUT of claim 11 , which is symmetric about

13. 12. The MUT of claim 11, wherein a ratio of a distance from a center of the primary rounded distal portion to a center of the secondary rounded distal portion to a diameter of the primary rounded distal portion, the secondary rounded distal portion, or both, is from about 3:1 to about 5:

1.

14. 12. The MUT of claim 11, wherein a ratio of a distance from the center of the primary distal rounded portion to the center of the secondary distal rounded portion to a minimum width of the mesial portion is from about 2:1 to about 7:

1.

15. 12. The MUT of claim 11, wherein a ratio of a diameter of the primary rounded distal portion, the secondary rounded distal portion, or both, to a minimum width of the mesial portion is from about 1:1 to about 3:

1.

16. further comprising one or more portions of the piezoelectric layer; (a) the secondary first electrode is coupled to the primary first electrode by a first portion of the one or more piezoelectric layer portions; (b) the secondary second electrode is coupled to the primary second electrode by a second portion of the one or more piezoelectric layer portions; (c) the secondary third electrode is coupled to the primary third electrode by a third portion of the one or more piezoelectric layer portions; or (d) any combination thereof.

17. (a) the first electrode has a shape that is offset inward from the shape of the first cavity; (b) the first electrode has a shape that is offset inward from the shape of the second cavity; (c) the first electrode has a shape that is offset inward from the shape of the third cavity; or (d) any combination thereof.

18. (a) the secondary first electrode has a shape that is offset inward from the shape of the primary electrode; (b) the secondary second electrode has a shape that is offset inward from the shape of the primary second electrode; (c) the secondary third electrode has a shape that is offset inwardly from the shape of the primary third electrode; or (d) any combination thereof.

19. (a) the secondary first electrode is coupled to the primary first electrode by a first piezoelectric layer; (b) the secondary second electrode is coupled to the primary electrode, the secondary electrode being coupled to the primary first electrode by a first piezoelectric layer; (c) the secondary third electrode is coupled to the primary third electrode by a first piezoelectric layer; or (d) any combination thereof.

20. The MUT of claim 1 , wherein at least a portion of the membrane is formed from plastic, ceramic, or both.

21. The MUT of claim 20 , wherein at least a portion of the membrane is formed from the ceramic, the ceramic comprising silicon.

22. The MUT of any one of claims 1 to 21, wherein at least a portion of the membrane has a thickness of about 1 μm to about 10 μm.

23. 23. The MUT of claim 1, wherein the MUT has a higher acoustic output at higher frequencies than the same MUT without the second cavity, the second portion of the membrane covering the second cavity, the primary second electrode, and the secondary second electrode.

24. The MUT of claim 23 , wherein the high frequency comprises an ultrasonic frequency of 5 MHz or greater.

25. An imaging device comprising an array of the MUTs according to any one of claims 1 to 24.

26. 26. The device of claim 25, wherein the array comprises a linear array, a polar array, or a polygonal array.

27. 27. The device of claim 25 or 26, wherein the substrate, the membrane, or both of two or more adjacent MUTs in the array are contiguous.

28. 28. The device of claim 25, further comprising an application specific integrated circuit (ASIC) coupled to the array of MUTs.

29. 30. The device of claim 28, wherein the ASIC is configured to individually address each of the MUTs.

30. 30. The device of claim 28 or 29, wherein each MUT represents a single pixel of an ultrasound image acquired by the device.

31. 31. The device of claim 27, further comprising one or more crosstalk reduction elements disposed between adjacent MUTs in the array.

32. 32. The device of claim 31, wherein the one or more crosstalk reduction elements comprise grooves, trenches, acoustically attenuating materials, or combinations thereof, disposed between adjacent MUTs in the array.

33. (a) a component circuit; (b) a memory; (c) a communication unit; (d) a signal processing circuit; (i) an acoustic absorbing layer; (ii) a control unit; (iii) an imaging device according to any one of claims 25 to 30, and (iv) Coating layer Equipped with (e) an imaging subassembly; An imaging assembly comprising:

34. 34. The imaging assembly of claim 33, further comprising a power source, a charging port, a display, or any combination thereof electrically coupled to the component circuitry, the memory, the communications unit, the signal processing unit, the imaging subassembly, or any combination thereof.

35. 35. The imaging assembly of claim 33 or 34, wherein one or more of the component circuitry, the memory, the communication unit, the signal processing unit, and the imaging subassembly are electrically coupled.

36. (a) the acoustically absorbing layer is proximate to the control unit; (b) the control unit is proximate to the imaging device; (c) the imaging device is proximate to the coating layer; or 36. The imaging assembly of any one of claims 33 to 35, wherein (d) any combination thereof.

37. (a) the coating layer is distal to the imaging device; (b) the imaging device is distal to the control unit; (c) the control unit is distal to the acoustically absorbing layer; or 37. The imaging assembly of any one of claims 33 to 36, wherein (d) any combination thereof.

38. 36. The imaging assembly of claim 33, wherein the acoustic absorbing layer is proximal or distal to the acoustic array.

39. 39. The imaging assembly of any one of claims 33 to 38, wherein the power source comprises a battery.

40. 40. The imaging assembly of claim 33, wherein the control unit comprises an application specific integrated circuit (ASIC) coupled to the array of MUTs.

41. 41. The imaging assembly of claim 33, wherein the coating layer comprises an acoustic lens.

Images