RU2800791C2 - Synthetic lenses for ultrasonic imaging systems - Google Patents

Abstract

FIELD: ultrasound imaging.

SUBSTANCE: essence of the invention lies in the fact that the ultrasound imaging system contains: a) an ultrasonic transducer containing a plurality of piezoelectric micromachined ultrasonic transducer elements (pMUT), with a plurality of transducer elements lined up in one or more rows and one or more columns, each of the plurality of pMUT transducer elements is provided with two or more pins, wherein two elements of the plurality of pMUT transducer elements are accessed simultaneously, the two elements being adjacent to each other in the same row of one or more rows, and the plurality of transducer elements comprising a top section, a central section and a bottom section, each of which contains a first number of rows and a second number of columns for transmitting and receiving ultrasonic pulses of the reflected ultrasonic signal, and the transmission and reception of ultrasonic pulses of the reflected ultrasonic signal from these sections are used to focus the reflected ultrasonic signal in the azimuth direction using a first beam former, while focusing in elevation is provided through the use of a second beam former; and b) one or more circuits coupled to a plurality of pMUT transducer elements, the one or more circuits being electronically configured to: i) transmit an ultrasonic pulse from the ultrasonic transducer; ii) receive the reflected ultrasonic signal with an ultrasonic transducer; and iii) electronic control with the ability to focus the ultrasonic pulse or reflected ultrasonic signal in the elevation direction.

EFFECT: improving the quality of ultrasound imaging and reducing energy consumption in the implementation of ultrasound imaging.

24 cl, 63 dwg

Description

Link to related application

[0001] This application claims priority from U.S. Patent Application No. 62/792,821, filed January 15, 2019, the contents of which are incorporated herein by reference in their entirety.

Background of the Invention

[0002] For ultrasound imaging, transducers are used that transmit an ultrasonic beam in the direction of the target to be imaged, after which the reflected wave is received by the transducer and converted into an electrical signal that is further processed to obtain an ultrasound image. Traditionally, for obtaining two-dimensional (2D) images, the ultrasonic transducer contains a one-dimensional (1D) transceiver grating emitting an ultrasonic beam. A mechanical lens located in the upper part of the grating focuses the ultrasonic wave in the elevation plane. Once the structural properties and thus the corresponding functional properties of the grating and the mechanical lens have been formed, these properties can no longer be changed.

The essence of the present invention

[0003] In the medical field, piezoelectric sensors have been used for diagnostic imaging for two decades. Typically, their design involves the use of bulk piezoelectric films. These films form piezoelectric elements that are aligned in columns in the azimuth direction. Each column may be driven by transmission drive circuits. By using different time delays in successive columns, it is possible to focus the transmitted beams in the azimuth direction.

[0004] The location of the matrix array of piezoelectric elements in height makes it possible to focus the array beam by electronic means into a narrow beam in the elevation plane. A single row of piezoelectric transceiver array elements does not provide electronic focusing in the elevation direction or across the thickness of a two-dimensional (2D) ultrasound image. A standard 2D ultrasound image is formed in the azimuth plane with a certain thickness in the elevation direction (i.e., the standard technique for limiting the beam to a thin slice of the image is to mechanically focus the beam in this transverse or elevation direction, or by contouring the piezoelectric elements in this direction, or beyond account of the lens effect of each element). Recently, it has been found that focusing in the elevation direction can be achieved due to the piezoelectric properties of the elements in this direction. In this technique, known as obscured polarization, strong ordered electric fields are uniformly applied to each element to narrow the polarization of the piezoelectric elements so that they are maximally polarized at the center and less polarized towards each end of the element in the elevation direction. This technique makes it possible to shape the acoustic permeability of each piezoelectric element so that it is greater along the longitudinal centerline of the array, and that it decreases towards each end in the elevation direction. A significant drawback of this technique lies in the difficulty of finely adjusting the magnitude and gradient of polarization shading. Other well-known techniques with lower drive voltage can be used to provide focusing in elevation, but they also have certain disadvantages. For example, US Pat. No. 2005/0075572 A1 uses a mechanical lens to assist in elevation focusing.

[0005] In other methods, a transducer composed of a plurality of rows may be used. For example, 1.5-dimensional (1.5D) and 1.75-dimensional (1.75D) transducers can provide some focus adjustment in elevation using multiple transmit and receive operations and receive beamforming using, for example, two-stage shapers beam. However, these methods provide only a limited degree of elevation focus and a reduced image frame rate due to the need for multiple transmission and reception operations. In addition, additional calculations may be required, increasing power consumption and costs, which is undesirable for budget portable devices, which are usually recorded from rechargeable batteries.

[0006] According to one aspect described herein, ultrasonic imaging systems are provided, comprising: a) an ultrasonic transducer comprising a plurality of piezoelectric micromachined ultrasonic transducer elements (pMUTs), each of the plurality of pMUT transducer elements being provided with two or more leads; and b) one or more circuits coupled to a plurality of pMUT transducer elements, the one or more circuits being electronically configured to: i) transmit an ultrasonic pulse from the ultrasonic transducer; ii) receiving the reflected ultrasonic signal with an ultrasonic transducer; and iii) electronic control with the ability to focus the ultrasonic pulse or reflected ultrasonic signal in the elevation direction. In some embodiments of the present invention, the plurality of transducer elements comprises a matrix array of transducer elements. In some embodiments of the present invention, this lattice is two-dimensional. In some embodiments of the present invention, this lattice is characterized by a shape selected from such shapes as: rectangular, square, round, oval, parabolic, spiral or arbitrary shape. In some embodiments of the present invention, a plurality of transducer elements are arranged in one or more rows and one or more columns. In some embodiments of the present invention, each transducer element in a column is driven by a multilevel pulse that is generated by one or more circuits. In some embodiments of the present invention, each transducer element in a column is driven by a sequence of multilevel pulses generated by one or more circuits. In some embodiments of the present invention, the magnitude, width and shape of the pulse, the pulse repetition rate, or combinations of these multilevel pulse parameters are electrically programmable. In some embodiments of the present invention, an electrically programmable pulse delay is provided. In some embodiments of the present invention, one or more pulses in a pulse train are electrically programmable. In some embodiments of the present invention, the multilevel pulse is in the form of a sine wave, a digital square, or an arbitrary waveform. In some embodiments of the present invention, the first terminal of one or more elements of the plurality of pMUT transducer elements is connected to one or more circuits, and the second terminal and an optional additional terminal are connected to a bias voltage. In some embodiments of the present invention, one or more elements of a plurality of pMUT transducer elements are bidirectionally polarized at their different locations, with the polarization intensity varying depending on the position of one or more elements of the plurality of pMUT transducer elements in a row, and each element of number of a plurality of conversion elements pMUT is provided with at least three outputs. In some embodiments of the present invention, one or more elements of the plurality of pMUT transducer elements are polarized in only one direction, with each element of the plurality of pMUT transducer elements having only two leads. In some embodiments, implementation of the present invention, the polarization will be stronger for the central rows and weaker for the outer rows, thereby providing apodization in the elevation direction. In some embodiments of the present invention, one or more circuits includes one or more of the following circuits: a transmit drive circuit, a receive amplifier circuit, and a control circuit. In some embodiments of the present invention, the transmission drive circuit is configured to drive one or more pMUT transducer elements in a column and is driven by the transmission channel signals, the transmission channel signals being electronically delayed relative to the delay applied to other transmission channels driving other pMUT transform elements in different columns. In some embodiments of the present invention, one or more elements of a plurality of pMUT transducer elements in a column fire with substantially the same delay or different delays. In some embodiments of the present invention, control is carried out in real time. In some embodiments of the present invention, each element of the plurality of transducer elements comprises a first terminal and a second terminal, the first terminal is electronically connected to one or more circuits, and the second terminal is connected to the corresponding terminals of other elements from the plurality of transducer elements . In some embodiments of the present invention, the ultrasound imaging system further includes an outer lens mounted on top of the plurality of transducer elements, the outer lens being configured to provide additional focus in the elevation direction. In some embodiments of the present invention, the control circuit is operable to electrically adjust the relative delays between drive pulses for transducer elements of the same column. In some embodiments of the present invention, the transmission channel and additional transmission channels are configured to adjust the relative delays between adjacent columns by electrical means, wherein the control circuit is configured to set the relative delays for the first group of transducer elements in the column such that the first group of transducer elements in one and the same row showed a relative delay, essentially similar to the delay of the second group of transducer elements in the initial row. In some embodiments of the present invention, the transmission channel and the additional transmission channels are electronically configured to adjust the relative delays between adjacent columns, wherein the control circuit is configured to set the relative delays for the transducer elements in the column such that the first group of transducer elements in the same volume the same row was characterized by independent delays relative to the second group of transducer elements in the same row for other columns. In some embodiments of the present invention, the control circuit is configured to electrically adjust the relative delays of the column so that they are symmetrical with respect to the transducer elements in the center row of the column. In some embodiments of the present invention, the control circuitry is operable to electrically adjust the relative delays so that they increase linearly in the column, thereby directing the ultrasonic beam in the elevation direction. In some embodiments of the present invention, the control circuitry is configured to electrically control the relative delays to allow adjustment of the thickness of the slices in the elevation direction. In some embodiments of the present invention, a plurality of transducer elements comprises an upper section, a central section, and a lower section, each of which contains a number (a number) of rows and a number (a number) of columns for pulsed transmission and reception of a reflected ultrasonic signal, and pulsed transmission and reception of the reflected ultrasonic signal from these sections are used to focus the reflected ultrasonic signal in the azimuth direction using the first beamformer, and the elevation focusing is provided using the second beamformer. In some embodiments of the present invention, scan lines across said sections are synchronized to minimize image errors due to movement of the rendered target by completing the scan of the entire column before proceeding to scan subsequent columns. In some embodiments of the present invention, the focal length in the elevation direction is programmed electronically. In some embodiments, implementation of the present invention, the pulse transmission and reception of the reflected signal of the upper section and the lower section are carried out simultaneously. In some embodiments of the present invention, errors in the generated image, due to the movement of the rendered target, are minimized by forming a beam of parallel rays to build scan lines. In some embodiments of the present invention, the elevation focusing and the elevation apodization are performed electronically to minimize errors due to said movement. In some embodiments of the present invention, a multilevel pulse is used to implement apodization electronically, with lower amplitude excitation for the outer rows and higher amplitude excitation for the central rows. In some embodiments of the present invention, the top section, center section, or bottom section comprises more than one subsection, each of which contains a number (number) of rows and columns for pulsed transmission and return signal reception. In some embodiments of the present invention, the plurality of transducer elements comprises five sections, with two outer sections transmitting and receiving azimuthally focused beams followed by two inner sections transmitting and receiving azimuthally focused beams, and a central section transmitting and receiving azimuthally focused beams, forming scan lines using a first level beamformer and providing elevation focusing using a second level beamformer. In some embodiments of the present invention, apodization is implemented in the elevation direction by electronic means. In some embodiments of the present invention, the ultrasonic transducer has a bandwidth that is not actually limited by signal loss due to mechanical lens loss. In some embodiments of the present invention, two elements from a plurality of pMUT transducer elements are accessed simultaneously, the two elements adjacent to each other in the same row of one or more rows, the plurality of transducer elements comprising an upper section, a central section and a lower section, each of which contains a first number of rows and a second number of columns for transmitting and receiving ultrasonic pulses of the reflected ultrasonic signal, and the transmission and reception of the ultrasonic pulse of the reflected ultrasonic signal of these sections are used to focus the reflected ultrasonic signal in the azimuth direction using the first beamformer , with elevation focusing provided by the use of a second beamformer, with mode B imaging assigning a receive channel to two transducer elements effectively combined in the same row, where the two elements now act as a single effective element, and several rows above and below containing these combined elements are connected to each other, and a different channel is assigned to the two transducer elements of the central section, consisting of two rows. In some embodiments of the present invention, 2N receive channels are used to access N columns. In some embodiments of the present invention, all elements of a plurality of transducer elements are actuated to generate pressure with focusing in elevation during a transmit operation, and during a receive operation, all elements from a plurality of transducer elements are used to reconstruct an image with focus in the azimuth direction and in elevation plane. In some embodiments, implementation of the present invention uses apodization to radiation in the elevation plane. In some embodiments of the present invention, the elevation focus is dynamic and is directed in the elevation plane. In some embodiments of the present invention, mechanical lenses are not used. In some embodiments of the present invention, one or more pMUT transform elements comprise a plurality of sub-elements configured to simultaneously perform transmit and receive operations. In some embodiments of the present invention, one or more pMUT transducer elements comprise a plurality of sub-elements, wherein the plurality of sub-elements have different resonant frequency responses. In some embodiments of the present invention, each of the plurality of pMUT transducer elements is provided with at least two leads. In some embodiments of the present invention, the control circuit is configured to determine the relative response delays of the transducer elements in the column, the control circuit comprising a coarse delay circuit configured to set a coarse delay and a fine delay circuit configured to set a fine delay. In some embodiments of the present invention, beam steering is performed using a coarse delay scheme and elevation focusing is performed using a fine delay scheme. In some embodiments of the present invention, the fine delay for one column is independent of the fine delays for other columns. In some embodiments of the present invention, the control circuit is configured to electrically control the relative delays to be piecewise linearly increased or decreased in a column, wherein the number of piecewise linear delay segments is an integer of at least 2. In some embodiments of the present invention, the circuit control is implemented on ASIC (Application Specific Integrated Circuit). In some embodiments of the present invention, the control circuit is operable to electrically adjust the relative delays along the column by adding a linear delay and an arbitrary fine delay. In some embodiments of the present invention, the linear delay and arbitrary fine delays in one column are independent of the other linear delay and arbitrary fine delays in the other column of the ultrasonic transducer, allowing arbitrary direction and three-way focusing. In some embodiments of the present invention, each element of the plurality of pMUT transducer elements outputs a plurality of vibration modes, where one or only one vibration mode is activated when the input is band-limited such that it is less than the bandwidth of the remaining modes of the plurality of vibration modes bordering with the specified one or only one vibration mode. In some embodiments of the present invention, each of the plurality of transducer elements pMUT outputs a plurality of vibration modes, where frequencies generated from the first plurality of vibration modes overlap with frequencies from the second plurality of vibration modes. In some embodiments of the present invention, each of the plurality of pMUT transducer elements simultaneously outputs a plurality of vibration modes when driven by a broadband frequency input signal that includes the center frequencies of the plurality of vibration modes. In some embodiments of the present invention, one or more circuits are electronically configured to provide electronic control of apodization in the elevation direction. and controls in their immediate vicinity.

[0007] In some embodiments of the present invention, one or more circuits are electronically configured to perform B-mode imaging in the azimuth plane in a single operation, with selected elements subject to transmission beamformer delays in the azimuth direction, and with the additional ability to perform B-mode imaging in the orthogonal plane using a transmit beamformer to correct for delays in the elevation direction during a subsequent operation to display two-projection images formed along two orthogonal axes using the obtained synthetic aperture method. In some embodiments of the present invention, it is envisaged that when imaging in the azimuth plane, focusing in elevation is provided by giving additional delays to elements in a column, and when imaging in an elevation plane, by giving additional delays to elements in rows along the azimuth axis in order to provide additional focusing in the azimuthal plane.

[0008] According to another aspect described herein, methods for obtaining three-dimensional (3D) images using an ultrasound imaging system according to the present invention are provided, which include the following steps: a) transmitting an ultrasound pulse by a plurality of pMUT transducer elements, which involves: a plurality of delays in the azimuth direction for a series of transmissions with a specific direction angle in the elevation direction, controlled by the second set of delays applied to more than one element of the plurality of pMUT transducer elements in the same column; and repeating step a) a predetermined number of times with an additional direction angle in the elevation direction for each repetition of step a); b) receiving the reflected ultrasonic signal by a plurality of transducer elements pMUT; and c) reconstructing the image using the reflected ultrasonic signal received from the plurality of pMUT transducer elements. In some embodiments of the present invention, the delays in the first delay set are equal in magnitude and the delays in the second delay set are equal in magnitude. In some embodiments of the present invention, the use of the first set of delays further includes: a) focusing in the azimuth plane by varying the value of one or more delays in the first set of delays in azimuth; and b) focusing or directing the beam in the elevation direction by varying the value of one or more delays in the second set of delays for more than one element of the plurality of transducer elements pMUT along a particular column. In some embodiments of the present invention, a series of transmissions is characterized by a specific focus. In some embodiments of the present invention, the image is three-dimensional and displays a volume. In some embodiments of the present invention, the delays in the first delay set are not all equal in magnitude, and the delays in the second delay set are not all equal in magnitude. In some embodiments of the present invention, the predetermined number is less than 100. In some embodiments of the present invention, the predetermined number is greater than 1000.

Inclusion in the description by reference

[0009] The contents of all publications, patents, and patent applications cited in this application are incorporated herein by reference to the same extent as if the contents of each individual publication, patent, or patent application were specifically and separately indicated to be incorporated by reference. .

Brief description of the figures

[0010] A deeper understanding of the features and advantages of the subject matter of the present invention can be obtained from the following detailed description, which discloses illustrative embodiments of the present invention, and the accompanying drawings.

[0011] FIG. 1 schematically shows an embodiment of an ultrasonic system according to the present disclosure, including a pMUT array transducer for transmitting and receiving ultrasonic beams, pMUT array control electronics, other computing, control, and communication electronics, a display device, and a recording unit, wherein the lattice of pMUT elements is directed to the target object, the image of which is to be built.

[0012] FIG. 2 schematically shows an example of an implementation of an ultrasonic transducer according to the present disclosure.

[0013] FIG. 3A schematically shows an example implementation of a piezoelectric micromachined ultrasonic transducer element (pMUT) with two conductors.

[0014] FIG. 3B schematically shows an example implementation of a pMUT element containing two sub-elements, each of which is provided with two or more electrodes.

[0015] FIG. 3C schematically shows an embodiment of a pMUT element with two sub-elements each provided with two electrodes, the first electrode of the first sub-element connected to one of the electrodes of the second element and the second electrode of the first element connected to the other electrode of the second sub-element.

[0016] FIG. 4 shows an example array pMUT of an ultrasonic transducer system according to the present disclosure.

[0017] FIG. 5A is an exemplary cross section of a pMUT piezoelectric array element according to the present disclosure.

[0018] FIG. 5B is an example of a symbolic representation of the piezoelectric element shown in FIG. 5A.

[0019] FIG. 6 shows the orientation of dipoles in a piezoelectric element according to the present disclosure in an unpolarized state during polarization and after polarization.

[0020] FIG. 7 shows an example of connecting a piezoelectric element according to the present description to a low noise amplifier (LNA) in receive mode with a symbolic representation of the connection diagram.

[0021] In FIG. 8A shows an exemplary embodiment of a 2D array of pMUT cells with a single common ground or bias electrode for electrically trimming linear transducers in which rows can run in the vertical or horizontal direction and the size of the rows (e.g., number of pMUTs in a row) can be electrically programmed. .

[0022] FIG. 8B is an exemplary embodiment of a 2D array of pMUT cells, with biased connection points and/or actively driven pins shown.

[0023] FIG. 9 is an exemplary embodiment of a linear converter showing a plurality of ground and bias electrodes providing different polarization directions for each pMUT element.

[0024] In FIG. 10A shows an exemplary implementation of a pMUT array with multiple membranes in each piezoelectric element and the ability to use different polarization directions for the membranes controlling the piezo material and different polarization intensities per row.

[0025] In FIG. 10B is an example of a practical implementation of the grating shown in FIG. 10A, which shows the connection points of the bias voltage leads after polarization.

[0026] FIG. 11A shows an exemplary interconnection diagram of two pMUT elements with an ASIC device containing transmit and receive drive circuits and other functional elements.

[0027] In FIG. 11B is an exemplary circuit diagram of the ASIC device shown in FIG. 11A, where one column of electronics directly mates with one column of pMUT elements to form a larger composite transducer element.

[0028] In FIG. 12A and 12B are schematic representations of implementation examples of elevation focusing ultrasonic transducers as described herein.

[0029] FIG. 13A shows an exemplary diagram of an ultrasonic transducer with transducer elements arranged in rows M and columns N, this transducer including three lanes that consist of rows and/or columns, where each of said lanes can be selected to be driven separately. , and where the columns in each band share the same control signal generated by the transmission drive circuit(s).

[0030] FIG. 13B shows an exemplary diagram of an ultrasonic transducer with transducer elements arranged in rows and columns; wherein two elements in a row are effectively brought together for transmission and reception, and the transducer contains three blocks of transducer elements in rows and/or columns, and the upper and lower blocks of transducer elements can be driven by one channel to perform transmission and/or reception operations , while the central unit may be driven by another channel to perform transmit and/or receive operations.

[0031] In FIG. 14 shows an exemplary diagram of a number of scan lines that make up an ultrasound image frame.

[0032] FIG. 15 is an exemplary diagram for obtaining the scan line shown in FIG. 14.

[0033] FIG. 16 is an exemplary diagram for achieving elevation focus using delays applied to different bands.

[0034] FIG. 17A is a schematic illustration of an implementation example of a delay circuit according to the present disclosure with a plurality of on/off relays providing accurate delay(s) for elements in a column.

[0035] FIG. 17B is a schematic illustration of an implementation example of a delay circuit according to the present disclosure providing coarse delay(s) for elements in a column.

[0036] FIG. 17C schematically shows an example implementation of a delay circuit that provides coarse and/or fine delay(s) for elements in a column.

[0037] FIG. 17D shows details of the additional circuit shown in FIG. 17C.

[0038] FIG. 18A is a diagram illustrating beam direction or beam focusing in the azimuth direction using the azimuth delay from the transmission channels.

[0039] FIG. 18B is an exemplary diagram of the transducer elements and their delays, the delays being electronically programmable and substantially the same for more than one column of transducer elements.

[0040] FIG. 19 is an exemplary transmission excitation pulse diagram with delays for a column of transducer elements where the delays are symmetrical about the center element.

[0041] FIG. 20 shows an exemplary delayed transfer drive pulse diagram for converter elements in different columns.

[0042] FIG. 21 is an exemplary circuit for generating various delays using internal counter signals.

[0043] FIG. 22 is an illustrative diagram of a pulse generator with two digital inputs that generates an output signal in the form of a transmit excitation pulse/pulses.

[0044] FIG. 23A shows illustrative elevation beam plots of a simulated 24×128 transducer array array with 0° lateral deflection (left plot) and 45° lateral deflection (right plot), showing the differences between multiple methods of focusing in the elevation direction compared to no focusing. in the direction of elevation.

[0045] FIG. 23B shows an example implementation of a diffuse transmission scheme that focuses transmission in the elevation direction using a 24 × 128 2D array of transducer elements, in which the shaded circles represent the active transducer elements in each column, and where symmetry in the elevation direction can be used (assuming that focusing is carried out in the elevation plane of symmetry). This transmission scheme can produce about a third less pressure than when using all the 24 x 128 active elements.

[0046] FIG. 24A is an assembly diagram of an imager according to embodiments of the present invention.

[0047] FIG. 24B shows an example of one embodiment of a converter located on a substrate and an ASIC device on another substrate with interconnection facilities.

[0048] FIG. 25 is a diagram of an array of piezoelectric elements capable of performing 2D and 3D imaging according to embodiments of the present invention.

[0049] FIG. 26 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0050] FIG. 27 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0051] FIG. 28 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0052] FIG. 29 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0053] FIG. 30 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0054] FIG. 31 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0055] FIG. 32 is a schematic drawing illustrating an array of piezoelectric elements according to embodiments of the present invention.

[0056] FIG. 33A is a diagram of an imaging system according to embodiments of the present invention with piezoelectric elements wired in a column.

[0057] FIG. 33B is a diagram of an imaging system according to embodiments of the present invention with piezoelectric elements in a column capable of programmable transmission and reception.

[0058] FIG. 34A is a diagram of an imaging system according to embodiments of the present invention with piezoelectric elements in a column connected by wire connections.

[0059] FIG. 34B is a diagram of an imaging system according to embodiments of the present invention with piezoelectric elements in a column capable of programmable transmission and reception.

[0060] FIG. 35A shows one embodiment of a piezoelectric element coupled to a circuit element according to embodiments of the present invention.

[0061] In FIG. 35B shows an example of one embodiment of a piezoelectric element coupled to a circuit element according to embodiments of the present invention, the piezoelectric element being capable of programmable transmission and reception.

[0062] In FIG. 36 shows a control circuit for a plurality of piezoelectric elements according to embodiments of the present invention.

[0063] FIG. 37 shows a control circuit for a plurality of piezoelectric elements according to embodiments of the present invention.

[0064] FIG. 38 shows a transmit excitation waveform according to embodiments of the present invention.

[0065] FIG. 39A shows a transmit excitation waveform according to embodiments of the present invention.

[0066] FIG. 39B shows a transmit excitation signal waveform according to embodiments of the present invention, where the abbreviation TxB CLK stands for a high speed clock that can be used to generate a TxA and TxB waveform that is generated to provide pulses for transmission channels.

[0067] FIG. 40 shows a transmit excitation waveform according to embodiments of the present invention.

[0068] FIG. 41 shows output/input signals of various circuits in an imager assembly according to embodiments of the present invention.

[0069] FIG. 42A is a plot of elastic transmission wave amplitude versus angle according to embodiments of the present invention.

[0070] FIG. 42B shows a window for an apodization process according to embodiments of the present invention.

[0071] In FIG. 43 is a schematic view illustrating the assembly of an imager according to embodiments of the present invention.

[0072] FIG. 44 shows typical deflection angles of transducers according to embodiments of the present invention.

Detailed description of the present invention

[0073] Traditionally, a 2D ultrasound image can be generated using various algorithms, similar to those described by the author named Fredrik Lingvall (Lingvall, F., 2004, “Time domain reconstruction methods for ultrasound imaging using matrix lattice: A statistical method ") [cm. http://www.signal.uu.se/Publications/pdf/fredrik_thesis.pdf]. One example of such a solution is the use of a relative delay to excite signals along the columns of piezoelectric elements in the azimuthal direction. The beams can be focused in the azimuth direction electronically by varying the electronically programmable delay applied to the signal for different columns in the azimuth direction. However, focusing in a direction perpendicular to the azimuth direction (eg, in the elevation direction) is usually achieved using a mechanical lens. A mechanical lens allows only one focus at a time, so different elevation focusings may require different lens designs. In addition, a fixed mechanical lens does not provide the focus required for 3D ultrasound imaging.

[0074] 3D ultrasound imaging is too complex, expensive, and energy intensive when implemented using existing portable ultrasound imaging systems. Some of the embodiments of the claimed invention described herein provide systems and methods capable of using low cost, energy efficient, portable ultrasound transducers and high resolution ultrasound imaging systems configured for use in 2D and 3D ultrasound imaging. The ability to implement these low cost, high performance systems may depend on the pMUT elements used, which can be assembled on a semiconductor wafer in a high volume, low cost manufacturing process similar to high volume semiconductor manufacturing. In the embodiments of the present invention, such pMUT elements form a 2D array, where each element is connected to an electronic circuit, and the array of pMUT elements and the circuit matrix are aligned relative to each other on different semiconductor wafers and combined together, forming a cell, where each piezoelectric element is connected to a control circuit element, and each piezoelectric element can be provided with two or more terminals, as shown in Fig. 3B and 3C. These pMUT elements can also have a wide bandwidth, making these transducers suitable for wideband imaging, unlike prior art piezoelectric volumetric transducers. Older transducers may have limited bandwidth, requiring different transducers for different frequency ranges. Therefore, having a single transducer covering a wide frequency range, such as 1-12 MHz or more, can improve the user's convenience in examining patients without the user necessarily having to switch to a different transducer when examining different organs where completely different frequencies are required. This can result in cost savings. The broadband performance of the pMUT elements of the present invention can be achieved in at least two different ways. In some embodiments of the present invention, the transducer element comprises two or more sub-elements, with each sub-element resonating at a separate center frequency. In such a combination, the composite element may cover a wider strip (see, for example, Fig. 28). In other embodiments, implementation of the present invention, the membrane can be designed in such a way that it can support multiple resonant modes in a single membrane. Resonance can be characterized by the presence of a fundamental mode, where the resonance occurs at a certain frequency. Other resonances can also take place on the membrane, for example, the second and third resonances. These resonances may or may not be associated with harmonics. The bandwidth around these resonances can overlap with the bandwidth around other resonances, resulting in an overall wide bandwidth. If the input signal applied to the pMUT has a limited bandwidth, such as limited to one resonance, then other resonances may not appear. The transducer element can output multiple vibration modes simultaneously when driven by a broadband frequency input that includes the center frequencies of various resonances.

[0075] In addition, existing transducers using a mechanical lens to focus in the elevation direction may also incur lens attenuation loss, which reduces image quality. When using embodiments of synthetic lenses according to the present description, the need for a mechanical lens is eliminated. Sometimes a slightly curved, weak, deep focus lens may be used, or a flat, thin impedance matching layer on top of the transducer may be used instead. This can significantly reduce attenuation losses.

[0076] Instead of using mechanical lenses, the imaging systems described herein use electronic lenses, which have the advantage of eliminating the need to build a fixed focal length mechanical lens. In addition, the electronic lenses described herein are characterized by high flexibility, allowing the focal length to be changed in the elevation plane, and dynamic focusing depending on the depth. In addition, side lobes in the elevation direction can be suppressed by apodization, which allows better control of the slice thickness in the elevation plane. The real-time electronic control of apodization in the elevation direction enables effective suppression of the side lobes in the elevation direction by electronic means.

[0077] Some embodiments of the claimed invention described herein provide ultrasound imaging systems capable of focusing in the elevation direction. Some embodiments of the claimed invention described herein provide ultrasound imaging systems configured to provide electronically controlled elevation with a programmable delay along columns and/or rows. In some embodiments, the implementation of the present invention, electronic control is carried out by introducing programmable delays in the transmission excitation circuit that drives the individual elements in the columns.

[0078] Some embodiments of the claimed invention described herein provide transducer elements (e.g., pMUT elements), i. e. piezoelectric elements that are arranged in a plurality of rows (with each of the rows extending in the azimuth direction) and columns (with each of the columns extending in the elevation direction) in two dimensions. In some embodiments of the present invention, a section containing one or more rows around the central section of the rows can be focused in the azimuth direction. During one single transmission or reception, the data coming from this section can be focused in the azimuth direction, generating intermediate data. During additional transmission and reception, data from multiple sections can be focused in the elevation direction. This process can increase the thickness of the slices in the elevation direction. In some embodiments, implementation of the present invention such a process can be facilitated by the use of apodization in relation to the ultrasonic pulse/pulses.

Some definitions

[0079] Unless otherwise indicated, all technical terms used herein have a common meaning understood by a person skilled in the art for which the described subject matter of the present invention is intended.

[0080] In the context of this document, the singular forms expressed by the indefinite articles and the definite article include the plural forms, unless the context clearly implies otherwise. Any reference to "or" in this document is intended to include "and/or" unless otherwise indicated.

[0081] In the context of this document, the term "about" refers to a value that deviates from the specified value by about 10%, 5% or 1%, including its increments.

[0082] In some embodiments of the present invention, imagers (interchangeably referred to herein as transducers) in the context of this document can be used, among other things, to perform the following operations: one-dimensional (1D) imaging, also known as A-scan; two-dimensional (2D) imaging, also known as B-scan; 1.5D renderings; 1.75D imaging, three-dimensional (3D) imaging, and Doppler imaging (Doppler imaging). In addition, the imager in the context of this document can switch to various imaging modes that are programmed in advance. In addition, using the transducers of the present invention, a two-projection imaging mode can be realized.

[0083] In some embodiments of the present invention, transducer elements according to the present invention (eg, pMUT elements) are referred to interchangeably as transceiver elements, piezoelectric elements, and piezoelectric elements. In some embodiments, implementation of the present invention, the transducer element in the context of this document includes one or more of the following elements: a substrate and a membrane suspended from the substrate; bottom electrode located on the membrane; a piezoelectric layer located on the lower electrode; and one or more upper electrodes located on the piezoelectric layer.

[0084] FIG. 1 shows an example of one embodiment of the ultrasound imaging system 100 described herein. In this embodiment of the present invention, the imaging system includes a portable device 101, wherein the device 101 includes a display 112 and a data recording unit 114 that is provided with a connection activated by a communication interface for connecting to a network 120 and external databases 122 such as electronic medical records. . This connection to external data sources can facilitate the creation of medical bills, the exchange of data, the fulfillment of requests or the transfer of other information of a medical nature. In this embodiment of the present invention, the system 100 includes an ultrasonic imager 126 (interchangeably referred to herein as a “probe”) that includes an ultrasonic imager assembly 108 (interchangeably referred to herein as a “cell assembly”), wherein the ultrasonic cell provided with pMUT gratings 102 assembled on a substrate. The pMUT array(s) 102 are configured to emit and receive ultrasonic waves under the control of an electronic control unit, such as an application specific integrated circuit (ASIC) 106 located on the imager, and another control unit 110.

[0085] In this particular embodiment of the present invention, the display 112 and/or at least part of the electronic communication control unit 110 may be located on the assembly 108. In some embodiments of the present invention, the display or part of the control unit 110 may be external to imager, but connected to the assembly 108 of the ultrasonic imager and his/her elements through a wired communication interface and/or wireless interface 124 communication. In some embodiments of the present invention, to facilitate user interaction, display 112 may include an input device, such as, for example, a touch screen, and a user-friendly interface, such as a graphical user interface (GUI).

[0086] In the same embodiment of the present invention, the pMUT array 102 is coupled to an application specific integrated circuit (ASIC) 106 located on a different substrate and in close proximity to the pMUT array 102. This array may also be coupled to a material with a different total resistance (impedance) and/or impedance matching material 104 that can be placed over the pMUT array. In some embodiments of the present invention, the imager 126 includes a rechargeable power supply 127 and/or an interface 128 for connecting to an external power source, such as using a USB (Universal Serial Bus Interface) power interface that is compatible with other USB signaling protocols. standards such as USB2 or USB 3. In some embodiments of the present invention, a wireless charging method is provided. In some embodiments of the present invention, the imager 126 includes an ECG (electrocardiogram) signal input interface 129 for the purpose of synchronizing the sweeps with the ECG pulses. In some embodiments of the present invention, the imager 126 is provided with an inertial sensor 130 to help guide the user.

[0087] Arrow 114 indicates ultrasonic transmission beams emitted by imager assembly 108, which are directed at body part 116 and form an image of volumetric element 118. Transmission beams are reflected from the rendered target and enter imager assembly 108 as indicated by arrow 114 In addition to the ASIC circuit 106, the visualization system 100 may include other control, communication, and computing circuits 110. It should be understood that the ultrasonic imaging assembly 108 may be a single self-contained unit as shown in FIG. 1, or it may include physically separate but electrically or wirelessly connected elements, such as part of the electronic control unit 110. One example of such a solution is illustrated in Fig. 2.

[0088] FIG. 2 is a diagram illustrating an imager 126 according to embodiments of the present invention. As can be seen in FIG. 2, the imager 126 may include the following elements: a transceiver cell(s) 210a for transmitting and receiving elastic waves; coating layer 212as which acts as a lens by controlling the direction of deflection and/or focusing of the elastic waves and also functions as an impedance boundary between the transceiver array and the human body, lens 212 may also help attenuate the signal that drives the transducer and also enters the transducer , and therefore it is also advisable to keep it at a minimum level, and with electronic elevation control this lens may not be required, and it can be replaced only by a thin protective layer of impedance matching, providing absolutely negligible losses; and a control unit 202a, such as an ASIC chip (or ASIC for short) for controlling the transceiver cell(s) 210a and connected to the transceiver cell(s) 210a via protruding contacts. The combination of a transceiver array with an ASIC connected to it is called a cell. Also provided are: an FPGA-type programmable logic array 214a for driving components of the imager 126 and circuit(s) 215a such as an analog front end (AFE) for signal processing/conditioning; a sound absorbing layer 203 for absorbing the waves generated by the transceiver cell(s) 210a and propagating towards the circuit 215a, where in some embodiments of the present invention the sound absorbing layer is located between the transducer and the ASIC, and in some other embodiments of the present invention these sound absorbing layers are not needed; a communication module 208a for communicating with an external device such as the device 101 through one or more ports 216a; a memory 218a for storing data; a battery 206a for supplying power to the imager components; and optionally a display 217a for displaying target organ images.

[0089] During operation, the user can initiate contact of the surface of the pMUT array 102 coated with the matching material 104 with a portion of the body part through which ultrasonic waves are transmitted in the direction of the imaged target 118. The imager receives the ultrasonic beams reflected from the imager target, and processes or transmits them to an external processor for image processing and/or reconstruction, and then to the portable device 101 for displaying the image. Other data may also be collected, calculated, displayed and displayed to the user on the display.

[0090] FIG. 1 shows an exemplary embodiment of a portable ultrasound imaging system 100, which in this case includes an imaging system probe 126 (interchangeably referred to herein as a “transducer”). This probe may comprise an imager pMUT assembly 108 coupled to electronic units such as control unit 202a as shown in FIG. 2. The probe 102 communicates with an external display device 204 using a communication interface and means 124.

[0091] This means of communication can be cable or wireless connections. For wired connections, many protocols can be used to provide data exchange, such as USB2, Lightning, and others. Similarly, a common protocol such as 802.11 or other protocols may be used for wireless connections. Similarly, the data recorder 114 may be external to the probe and may also communicate with the probe 126 via a wireless or wired means of communication.

[0092] When using an imager, for example, to image parts of a human or animal body, the transmitted ultrasonic waves are directed towards the target. Contact with the body is achieved by holding the imaging device in close proximity to the body, usually after application of a special gel to the body and application of the imaging device to this gel, creating an effective zone of contact that allows the emitted ultrasonic waves to pass into the body and return to the imager, reflected from the target. , and the reflected signal is used to create an image of the body part and display the results on the display screen, including graphs, charts and statistics, displayed with or separately from the images of the body part in a variety of formats.

[0093] It should be noted that the probe 126 may be designed in such a way that some of its parts are made physically separate and connected to each other via a cable or wirelessly. In this particular embodiment of the present invention, by way of example, a pMUT assembly and an ASIC circuit with some of the control and communication electronics may be located in a unit, often referred to as a probe. The part of the device or probe in contact with the body part contains the pMUT assembly.

[0094] FIG. 3A shows a standard piezoelectric element 214 in cross section. In this embodiment of the present invention, the piezoelectric element is provided with two electrodes, the first electrode 216 is connected to the signal conductor 215 and the second electrode 218 is connected to the second conductor 217 and may be conventionally connected to ground or other direct current (DC) field potential.

[0095] Piezoelectric elements have been used for decades for medical ultrasound imaging. However, the piezoelectric element can be thick-layered, reaching a thickness of, for example, about 100 µm, and typically requires +100 V to -100 V alternating current (AC) to generate an ultrasonic elastic wave of sufficient intensity to enable diagnostic imaging. . The frequency of this AC excitation signal can vary within the resonant frequency of the piezoelectric structures, and it can be in excess of 1 MHz in diagnostic imaging applications.

[0096] In some embodiments of the present invention, the power dissipated when the piezoelectric element is excited is proportional to C*V ² , where C is the capacitance of the piezoelectric element and V is the maximum voltage across the piezoelectric layer. During transmission, a plurality of piezoelectric elements may be fired simultaneously with slightly different delays to focus or deflect the beam. Simultaneous excitation of multiple elements can lead to an increase in temperature on the surface of the elements. It is highly desirable or necessary that the temperature does not exceed a predetermined threshold so as not to damage the rendered object. Thus, this threshold temperature limits the number of elements that can be actuated and the period of time during which they are excited.

[0097] In some embodiments of the claimed invention disclosed herein, the piezoelectric elements can be much thinner (typically about 5 microns or less) than standard type bulk piezoelectric elements. This significant reduction in thickness allows the use of lower voltage drive signals, ensuring that the piezoelectric elements maintain the same electric field strength as standard type elements. For example, the piezoelectric elements disclosed herein can drive voltages ranging from about 5-40V peak-to-peak.

[0098] The capacitance of piezoelectric elements can also be reduced by reducing the thickness of certain piezoelectric materials. Thus, as one example, when the drive voltage is reduced from 100 V to 10 V when driving a film 10 times thinner, the electrical capacitance can increase 10 times for thinner piezoelectric materials, and power dissipation can be reduced by a factor of 10. This reduction in power dissipation can also reduce heat generation and temperature rise in the imaging probe. Thus, by using lower drive voltages, the surface temperature of the pMUT can be reduced.

[0099] In some embodiments of the present invention, when using low voltage pMUTs with a given temperature, more pMUT elements can be energized, illuminating a larger area. This allows faster scanning of the target, especially if multiple emissions are required to scan the entire target in order to form its image. Often, a target area can be scanned through multiple emissions using different deflection angles and image data combined to produce a higher quality image.

[0100] It may also be advantageous to render at a high frame rate. The frame rate determines how many times per minute the target is rendered. High frame rate imaging is useful when examining moving tissue so that moving targets can be observed without blurring the image. In some embodiments of the present invention, the ability to drive more piezoelectric elements allows for increasing transducer aperture coverage per emission and minimizing the number of emissions to cover the entire aperture, which improves frame rates.

[0101] In some embodiments of the present invention, image quality can be improved by combining multiple image frames into one final frame with less noise. However, this can reduce the frame rate. When using a low power pMUT with a higher frame rate than standard type piezo films, for a given pMUT temperature rise, this averaging technique can be used due to the fact that low voltage pMUTs have lower power, providing an inherently higher initial frame rate. In some embodiments of the present invention, a synthetic aperture ultrasound imaging technique may be used to combine images.

[0102] In some embodiments, the implementation of the present invention, the possibility of simultaneous excitation of more piezoelectric elements improves the signal-to-noise ratio (SNR) and provides better quality of the reconstructed image.

[0103] In addition, as shown in FIG. 1, an ASIC circuit 106 is coupled to pMUT 102. The ASIC circuit may include low noise amplifiers (LNAs). In receive mode, the pMUTs are connected to the LNA via switches. LNAs convert the electrical charge in the pMUT, generated by the reflected ultrasonic beam exerting pressure on the pMUT, into an amplified, low-noise voltage signal. The signal-to-noise ratio of the received signal can be one of the key factors determining the quality of the reconstructed image. Thus, it is advisable to reduce the inherent noise in the LNA itself. This can be achieved by increasing the slope of the transfer characteristic of the input stage of the LNA amplifier. This can be done, for example, by using a larger current in the input stage. Higher current can increase power dissipation and build up heat. However, in cases where low voltage pMUTs are used with ASICs in close proximity, the power saved by low voltage pMUTs can be used to reduce the noise level in the LNA for a given overall temperature rise that is acceptable compared to high voltage converters.

[0104] In FIG. 3B schematically shows the pMUT element 220 described herein. In this embodiment of the present invention, pMUT element 220 includes two sub-elements 220a and 220b. In some embodiments of the present invention, each pMUT element includes one or more sub-elements. Each sub-element in this embodiment of the present invention is characterized by the presence of a piezoelectric layer 221, where the first electrode 223 is connected to the first conductor 222, the second electrode 225 is connected to the second conductor 227, and the third electrode 224 is connected to the third conductor 226, and the first conductors of all sub-elements are connected to each other. on the other hand, the second conductors of all sub-elements are interconnected connectors and the third conductors of all sub-elements are connected to each other.

[0105] In some embodiments of the present invention, pMUT element 220 includes two sub-elements 220a and 220b, with each pMUT element provided with two pins. For example, subcell 220a is provided with a first electrode 223 connected to first conductor 222 and a second electrode 225 connected to second lead 227; and the subcell 220b is provided with a first electrode 223 connected to the first conductor 222 and a second electrode 225 connected to the second terminal 227.

[0106] In some embodiments of the present invention, the pMUT element 220 includes one sub-element 220a, with each of the pMUT elements provided with two pins. For example, subcell 220a is characterized by having a first electrode 223 connected to the first conductor 222 and a second electrode 225 connected to the second terminal 227.

[0107] In some embodiments of the present invention, subcell 220a may be characterized by the presence of a plurality of subcells, each of which is provided with two electrodes, all of the first electrodes are connected to the first conductor, and all of the second electrodes are connected to the second conductor.

[0108] In FIG. 3C is a schematic diagram illustrating a pMUT element 228 with two sub-elements 228a and 228b. In some embodiments of the present invention, each pMUT element includes one or more sub-elements. In this embodiment of the present invention, each sub-element is characterized by having a piezoelectric layer 231 with a first electrode 230 connected to the first conductor 229 and a second electrode 232 connected to the second conductor 233, wherein the first conductors of all the sub-elements are connected to each other and the second conductors of all the sub-elements are interconnected connectors.

[0109] In some embodiments of the present invention, the sub-cell 228a or 228b may include a plurality of sub-cells, each of which is provided with two electrodes, and in the case when two sub-cells are provided in the cell, the first electrode of the first sub-cell is connected to the other electrode of the second sub-cell through a conductor , and the second electrode of the first subcell is connected to the remaining electrode of the second subcell.

[0110] In FIG. 4 shows a substrate 238 on which a plurality of piezoelectric micromachined ultrasonic transducer elements 239 (pMUTs) are disposed. In this embodiment of the present invention, one or more array elements form a transmit/receive array 240, and more than one transmit/receive array is located on the substrate 238.

[0111] Standard type transducer gratings use a piezoelectric material, such as lead zirconate titanate (PZT), formed by slicing a monolithic PZT block into individual piezo elements. But in most cases, it comes at a cost. For comparison, the pMUT arrays disclosed herein are placed on a substrate (eg, a wafer). The wafer may be of various shapes and/or sizes. For example, a wafer as described herein may have the shape and dimensions of a wafer used to make integrated circuits in semiconductor manufacturing technology. Such wafers can be produced in large quantities and at low cost. Examples are 6, 8, and 12 inch diameter wafers.

[0112] In some embodiments of the present invention, a plurality of pMUT arrays can be produced in batches at a low cost. In addition, integrated circuits can also be sized so that the connections required to communicate with the pMUT elements coincide with each other, and the pMUT array (item 102 in Fig. 1) can be connected to a mating integrated circuit ( 106), located in close proximity to it, usually vertically below the specified grating or proximal to it, at a distance of, for example, about 25-100 microns. In some embodiments of the present invention, the combination of elements 102, 104, and 106 is referred to as an assembly 108 or imager cell, as shown in FIG. 1. For example, one exemplary embodiment of assembly 108 may have 1024 elements coupled to an interfacing ASIC that has a corresponding number of signaling and receiving functionality for 1024 piezoelectric elements. In some embodiments of the present invention, the array size is not limited to 1024 elements. It can be more or less. More elements can be provided by using a plurality of pMUT arrays 102 together with a plurality of mating ASICs 106 and assembling them back to back with an appropriate amount of impedance matching material 104 coated. Alternatively, a single array may also be characterized by a large number of pMUT elements, in which these elements are arrayed in the form of a rectangle or in another form, and their number varies from less than 1000 to 10000. The pMUT array and a plurality of pMUT elements can be connected to mating ASIC circuits.

[0113] In FIG. 5A shows a cross section of one embodiment of a piezoelectric element 247. In this embodiment, the element 247 is characterized by having a thin piezoelectric film 241 located on a substrate 252. The piezoelectric film is provided with a first electrode 244 that is connected to a signal conductor 246. This electrode is usually located on a substrate on which a SiO ₂ crystal is grown. Next, there is a layer of TiO ₂ coated with platinum, which is sprayed with PZT or sol-gel PZT to form a thin layer of PZT as a piezoelectric film 241. This and the first metal electrode are patterned by etching to obtain the desired shape. A signal conductor 246 is connected to the first electrode. A second electrode 240 is grown over the thin film 241 and is connected to a second conductor 250. A third electrode 242 is also grown close to the second electrode, but is galvanically isolated from this second electrode. Connected to the third electrode is a third conductor 248. The actual electrode arrangement shown may vary in shape from square to rectangular, with adjacent elliptical or other shaped electrodes, or with ring electrodes where one electrode encloses the other. The piezoelectric film can be of various shapes, and it can be located in certain areas on the surface of the substrate over the cavity.

[0114] FIG. 5B is a symbolic representation of the piezoelectric element shown in FIG. 5A. In some embodiments of the present invention, the first conductor 246 is electrically connected to the first electrode 244. Such a connection can be made using metals, jumpers, and internal insulating layer dielectrics (ILDs), but these elements are not shown for ease of presentation. The first electrode contacts the piezoelectric layer 241. On the other side of the piezoelectric layer relative to the first electrode, a second conductor is located or grown. A second electrode 248 is connected to the second conductor 242. A third electrode 240 is adjacent to the electrode 248, and a third conductor 250 is connected to it. The first electrode 244 is also referred to as the "O" electrode. The second electrode is referred to as the "X" electrode, and the third electrode is referred to as the "T" electrode. It should be understood that the connection means for connecting the conductors to the electrodes, such as jumpers, dielectrics for internal insulating layers (ILD) and other metallized layers, for the sake of simplicity, are not shown in all the figures or are not described in detail. These details are well known to those skilled in the art. In addition, other details such as underlying membranes are not shown.

[0115] Due to the asymmetry of the crystal structure of PZT, an electrical polarity occurs, creating electrical dipoles. In a macroscopic crystal structure, these dipoles may be randomly oriented by default, as shown in FIG. 6 on the left. When the material is subjected to a mechanical load, each dipole can rotate, changing its original orientation to a direction that minimizes the total amount of electrical and mechanical energy stored in the dipole. If initially all dipoles are randomly oriented (i.e., the total polarization is zero), then their rotation may not significantly change the macroscopic total polarization of the material, as a result of which the piezoelectric effect manifested may turn out to be negligibly weak. Therefore, it is important to ensure that the initial state of the material is such that most of the dipoles can be generally oriented in the same direction. Such an initial state can be imparted to the material by its polarization. The direction in which the dipoles align is known as the direction of polarization. The orientation of the dipoles during and after polarization is shown in Fig. 6 (middle and right parts).

[0116] Therefore, initially it may be necessary to polarize thin piezoelectric films before using them. This can be done by applying a high voltage to the film, typically at a high temperature (eg 175° C.), for a certain period of time (eg 1-2 minutes or longer). In the piezoelectric element shown in Fig. 3, the pMUT element may have two terminals, and a high voltage may be applied to, for example, terminals 216 and 218. This high voltage may be about 15 V for a 1 μm thick piezoelectric film. This voltage is sufficient for polarization.

[0117] Prior art pMUT elements or other monolithic PZT piezo elements are typically provided with two electrodes. As indicated herein, a piezoelectric element may be characterized by having two (see FIG. 3) or more electrodes, as shown in FIG. 5A and 5B. In FIG. 5A and 5B show that during polarization, the first conductor can be connected to ground potential, while the second conductor is connected to a negative energized potential, say -15 V for a 1 µm thick PZT film, and is connected for a while at high temperature. the third electrode is energized with +15 V. This can create two directions of polarization on the PZT film, opposite for the film between the first and second conductors and the piezo film between the first and third conductors. After polarization is completed during a transmit or receive operation, the second and third conductors may be connected to ground or bias voltage while the first conductor is connected to an ASIC circuit driven by a transmission drive circuit during a transmit operation, or connected to an amplifier. LNA via switches during a receive operation. The second and third conductors may also be connected with a non-zero DC offset, where the offset values may be different.

[0118] The piezoelectric element in one embodiment of the present invention realizes transverse strain by effectively using the transverse strain constant d31 PZT, i. piezoelectric coefficient, to provide membrane displacement or convert membrane displacement into charge. The PZT element shown in FIG. 5A and 5B, with polarization directions orthogonal to the film in transmission mode, increases membrane displacement for a given excitation compared to the structure shown in FIG. 3A and 3C, where the film has only one direction of polarization. In this way, the transmission sensitivity can be increased, allowing the membrane bias to be increased per volt of applied transmission drive voltage.

[0119] In the receive mode, the orthogonal direction of polarization may generate more charge to be read by the LNA. The LNA connections are shown schematically in FIG. 7. To simplify the presentation, not all elements in the path of connecting the piezoelectric element to the LNA are shown. In some embodiments of the present invention, the piezoelectric element 260 is provided with a first electrode that is connected in series with an LNA amplifier switch 268 connected via conductor 262. The second electrode of the element 260 is designated 266 and may be connected with a DC bias of 0 V ( Earth). Reference numeral 270 denotes a reflected ultrasonic beam incident on pMUT element 260 and charging electrodes 266 and 274. It should be noted that the LNA may be configured to operate in voltage or charge mode. pMUT cells typically have high capacitance and for a given amount of charge they produce a lower voltage across the converter compared to much smaller bulk PZT cells when voltage control is used, with the voltage across the converter amplified. Since the input voltage of the LNA is low, a noisier output signal will be produced. Charge amplification can provide a better signal-to-noise ratio at the LNA output due to the high capacitance of the pMUT cells compared to voltage mode, especially when the pMUT cells generate a larger output charge for a given inlet pressure in receive mode. This is illustrated in FIG. 7, where any charge received by the capacitor Ct is transferred through the much smaller capacitor Cf, producing a higher voltage at the output of the LNA. These LNAs can also be configured with fast power-on or fast power-off capability (eg, within less than 1 microsecond).

[0120] Traditional 2D rendering is performed using columns of elements that are configured as a tall rectangle. In alternative embodiments, this may be achieved by using a plurality of smaller elements arranged in columns. Individual lattice elements can be combined with each other, acting as a single element of the 1D lattice forming a column. This is achieved by wiring these individual elements together to form one larger element that has one signal conductor and a common ground conductor. For this single, larger, two-terminal pMUT, transmit drive, receive read, and control are implemented.

[0121] In FIG. 8A schematically shows one embodiment of an ultrasound imaging system transducer array 300 according to the present invention. The grid shown is characterized by having nine pMUT elements arranged for illustration in three rows and three columns (ie 3 by 3). It should be understood that in practice the grid size may be larger or smaller as required. Non-limiting examples of these sizes include: 32 by 32, 32 by 64, 32 by 194, 12 by 128, 24 by 128, 32 by 128, 64 by 128, 64 by 32, and 64 by 194 (number of columns per number of rows or number of rows per number of columns).

[0122] For this lattice of pMUT elements, the schematic representation shown in FIG. 5V. The conductor of each piezoelectric element is connected to the electrode and is denoted by the value Oxy, where the value of x ranges from 1 to 3 and the value of y ranges from 1 to 3, as shown in FIG. 8B. The first conductor of each piezoelectric element is connected to the first electrode and is designated as O11. In addition, all elements of the electronically configurable imager are characterized by the presence of O terminals connected to the corresponding electronics located on another semiconductor wafer. All of the second electrodes of each cell, designated as electrodes X, are connected to the other electrodes X of the other cells via conductor 302. Conductor O is the signal conductor, while X is the ground or control line. In this embodiment of the present invention, which is illustrated in FIG. 8B, the O electrodes are connected to the ASIC in close proximity to the substrate on which the pMUT elements are located. In any illustrative example where a 32×32 pMUT array is provided, there are 1024 piezoelectric elements. In this case, 1024 "O" pin connections to the ASIC circuit can be provided, which are usually located under the pMUT chip. Each of these 1024 O lines is connected to the transmission drive circuit during the transmission operation and to the input of the LNA during the reception operation, and in the receive mode, the transmission drive circuit enters a high impedance state.

[0123] In FIG. 9 shows one embodiment of a 3 x 3 transducer array, with each element provided with three terminals/nodes, namely O, X, and T. The "O" nodes are denoted by the value Oxy, where the value of x ranges from 1-3, and the value of y ranges from 1-3. These O nodes may be connected to the drive and sense electronics in an ASIC where the X nodes may be collectively connected to a bias voltage source or ground, and the T nodes may be collectively connected to another bias voltage source or ground.

[0124] In FIG. 10A shows one embodiment of a pMUT array in which each pMUT element is provided with three leads. In this embodiment of the present invention, this array consists of 24 rows, and each row consists of 128 elements. Similarly, in some embodiments of the present invention, each column may consist of 24 elements, and all elements can be provided with three terminals, namely terminals O, X and T. For example, the electrode O for the element in the lower left corner is indicated as O _0.127 . This element may include two other electrodes, namely X and T. It should be noted that all elements in the row may be connected to the X0 conductor, and all T terminals may be connected to TO. During the polarization operation, all O pins can be connected to 0 V; all X pins can be connected to a negative potential of -0 V; and all T terminals can be connected to a positive potential of +0 V. As for the following rows, the potentials for row 1 can be higher than -1 V for X1 and +1 V for T1 until row R11 is applied maximum voltages are 11 V and -11 V. The voltages for the upper half of the rows can be symmetrical to the voltages of the lower half. Under such bias conditions, the circuit can be polarized at a high temperature of about 175°C. In FIG. 10B shows that after polarization to enable visualization, all X pins can be connected to each other, as well as to a bias voltage, which also applies to all T pins. It should be noted that the voltage for the X and T pins can be different. With this arrangement, due to the different polarizations along the column, apodization in the elevation direction can be provided, where leakage of the side lobes in the elevation plane can be minimized. In some embodiments of the present invention, the transducer array may also include only two terminals per element, such as an X terminal and an O terminal, and the T terminal may not be used.

[0125] In FIG. 11A is a schematic diagram illustrating the interconnection of two converter elements with an ASIC circuit 500. In some embodiments of the present invention, two transducer elements 502 are located on the same substrate 504 and are connected to an ASIC circuit having transmit and receive functions and other functions that is located on the other substrate 512. The input of the LNA amplifier 516 is connected via a switch 514 to the output 510, which connects it to the signal conductor of the transducer, i.e. output O. In some embodiments of the present invention, bias conductors 506 are connected to the ASIC circuit and then exit the ASIC for connection to ground or other bias voltages. They are the X pins of the converters that can be connected together with other X pins in the converter and the ASIC. The transfer drive circuit 518 may be controlled by a communication means external to the ASIC on the substrate 512, which is indicated at 520. It may also be connected to a switch 514 that is operated on a transfer mode connection. The output of the LNA amplifier and the input of the transmission drive circuit shown in FIG. 11A may require two different leads. It is possible to use a single output by using a multiple switch, similar to switch 514. In some embodiments of the present invention, a connection to the LNA output may be provided for communication with external electronics in the receive mode, and for the transmit mode, a transmit drive circuit output may be provided.

[0126] In FIG. 11B is a schematic diagram illustrating some functionality of the ASIC. Functionally, one column of electronics can be directly connected to one column of pMUT elements, forming larger composite line elements. It should be understood that the ASIC may contain schemas for other columns or rows and include other auxiliary schemas not shown. It should also be understood that the actual functionality required can be provided with different circuit topologies, as will be apparent to those skilled in the art. The image shown is for illustration purposes only.

[0127] In FIG. 11B schematically shows an example implementation of one column of ASIC circuit 600. In some embodiments of the present invention, conductor 608 is connected to respective signal conductors of one of the elements in the pMUT array shown in FIG. 8A-8B, namely O31. Similarly, element O21 shown in FIG. 8A-8B is connected to conductor 628 shown in FIG. 11V. The transmission drive circuit 606 may be connected to the conductor 608 shown in FIG. 11V. This transfer drive circuit 606 may be characterized by having a switch 602 connected to its input and connected to a terminal 616 (signal conductor for line element) which is connected to the input of the other transfer drive circuits in this column via the switches in this column. The switches may be controlled by a control unit 624 which, by communicating with an external controller, may determine which switch/switches should be activated. The signal conductor 616 may also be connected to the electronics to implement transmission beamformers. Conductor 608 may also be connected to switch 604, and the other side of switch 604 may be connected to similar switches in that column (eg, 622). Line 614 may also be connected to the input of a low noise amplifier (LNA) 618. Only one LNA may be required for each line element (or column). The LNA can be activated in receive mode by control unit 624, which also activates some switches (eg, 604) while deactivating other switches (eg, 602). In this case, the signal electrode of the pMUT elements can be connected to the LNA (via connection 608) to amplify the received signal and convert it to a low additive noise output voltage 620. It should be noted that in the receive mode, the controller can also cause the transmit drive circuits to go into a shutdown mode, in which their output impedance becomes too high to interfere with the receive signal. In transmit mode, when the piezo element is not expected to transmit, switch 610 can be activated and switches 602 and 604 disabled, ensuring a total zero drive voltage on the pMUT signal and the bias electrode for elements that should not transmit signals in transmit mode. Also connected to the ASIC is the X lines. Note that in FIG. 8A-8B show only one bias electrode X, although multiple bias electrodes may be provided. For example, in FIG. 9 shows an implementation with two bias electrodes (X and T). In principle, only two connections are needed for the entire array to connect the T and X electrodes, but for imaging with high image quality, it is desirable to have more of these connections. Increasing the number of connections for the T and X electrodes between the ASIC and the pMUT reduces the impedance in the T and X conductors connected in parallel to ground or bias sources, which reduces crosstalk. Crosstalk is the mixing of the signals from one imaging element with the signals from another imaging element, which creates noise and reduces image quality. When the current flowing in the T and X lines causes a voltage drop across the piezo element, which should ideally not be subjected to such a voltage, parasitic electrical coupling can occur. When the piezo is not transmitting or receiving electronically, the X, T, and O electrodes are locally shorted.

[0128] For simplicity, in FIG. 11B shows only the connection to just one of the two bias conductors (X in FIGS. 8A and 8B). But it should be understood that means also exist for connecting both X and T pins, supporting pMUT arrays in a manner similar to that shown in FIG. 9.

[0129] In some embodiments of the present invention, conductor 612 shown in FIG. 11B may be connected to X, 302 shown in FIG. 8B. In some embodiments of the present invention, conductor 613 shown in FIG. 11B may also be connected to X, 302, but at points closer to 613, and so on. Note that these additional interconnects 613 and 615 are not critical as at least one interconnect is needed (either 612 or 613 or 615). In FIG. 11B also does not show the circuits necessary to connect the electrodes T shown in FIG. 9. Necessary circuits can be similar to the circuits used to connect the X electrode.

[0130] In FIG. 11B shows that the receive output 620 and transmit input 616 may require two pins. But by using a multiplexer, just one output can also be used for this purpose.

[0131] The linear imager described herein may include a plurality of columns of piezoelectric elements, each column being connected to a controller via at least a signal output and bias outputs. The string is excited by pulses of the appropriate frequency. The remaining rows are excited by delayed versions of the pulse. The amount of delay for a certain line is such that it allows the transmitted result beam to be deflected to a certain angle or focused to a certain depth by performing operations known as beamforming.

[0132] The linear imager shown in FIG. 8 and 9 is an electronically configurable device. Using an example implementation of a piezo array in which 24 elements are lined up in one direction and 64 elements are lined up in the orthogonal direction (the azimuthal direction in this example), a 64-line imager can be created in which each line consists of 24 elements. However, this size can be adjusted electronically to change the number of elements in each line from 0 to 24, and any number of lines from among the 64 lines can be activated in azimuth.

[0133] Desirably, a thin slice of the elevation plane is rendered in the 2D or 3D imager, as shown in FIG. 12A and 12V. In this particular embodiment of the present invention, the elevation direction is the y-axis on the left side of the figure. The elevation plane 1201 is within the ya-za plane. In the same embodiment of the present invention, the azimuth plane 1202, i.e. the scanning plane, in the context of this document, runs perpendicular to the elevation plane. As shown in FIG. 12B, a mechanical lens focuses beams in the elevation plane, preventing them from being deflected to the side to form a much thicker slice in the elevation plane, and allowing them to strike other objects in that thicker elevation slice with unwanted reflections, becoming part of the received signal, which introduces additional noise in the signal and degrades the image quality.

[0134] If the beam goes far beyond the calculated slice thickness, it can potentially hit targets outside the required range, and reflections from them will create clutter in the reconstructed image. A mechanical lens formed on the surface of the transducer can focus beams in the elevation plane to a fixed slice thickness in elevation, as shown in FIG. 12B, where this thickness is at its minimum at the focal point in elevation, as shown in FIG. 12B and also indicated in FIG. 12A as a focal point in the elevation plane. Focusing electronically in 2D imaging will provide more accurate focusing in the elevation plane by dynamically focusing on reception as a function of time. In this case, the focal length in the elevation direction varies as the beam travels down towards the target, resulting in an excellent image quality. For 3D imaging, a fixed mechanical lens is not suitable because this particular slice in the elevation plane cannot be deflected or expanded to the desired volume. Therefore, electronically adjustable elevation focusing is the preferred option.

[0135] In some embodiments of the present invention, this is achieved by dividing the transducer into a number of different bands. As shown in FIG. 13A, in one particular embodiment of the present invention, a transducer with multiple transducer elements is organized into N columns, with each column containing M rows of transducer elements. The rows of elements may be divided into strip A including the first number of rows, with strip A containing up to N columns; a strip B including a second number of rows that form a central section of the rows, with each row containing up to N columns; and a C lane including a bottom section of rows with up to N columns. In some embodiments of the present invention, each of the lanes may be individually selected to drive, with the columns in each lane driven collectively by the transmission drive circuit(s). Lanes A, B and C may not overlap with adjacent lane(s). Alternatively, the bands may overlap some of their rows and columns with an adjacent band. In some embodiments of the present invention, all of these bands cover all columns of N transducer elements and their rows of M number. In some embodiments of the present invention, where programming is provided by electrical means, these bands together may cover only part of the array of M by N transducer elements.

[0136] In some embodiments of the present invention, the upper section A is organized such that all elements in this section are driven by the transmission drive circuit(s) dedicated to the column in which the element(s) are located. In this embodiment of the present invention, during a transmission operation, N transmission excitation schemes with unique delays driving N-th number of composite columns (each composite column may include elements from rows/bands A or B or C) are used to focus the ultrasonic beam in the azimuthal plane 1202. During the reception operation, the reflected signal that enters section A is beamformed to obtain scan lines A1, A2, A3, etc., as shown in FIG. 14. As can be seen in FIG. 14, the three bands of PMUT elements are labeled A, B, and C. These bands include rows of PMUT elements that, when the elements in a column are driven by a common transmission drive circuit, contain N drive circuits for N columns (i.e., a separate drive circuit for each column of N columns). When transmitting and receiving using band A, scan lines A1, A2, etc. can be generated. From section B, scan lines B1, B2, etc. can be generated; and scan lines C1, C2, etc. can be generated from section C. Now, using the data read from the three sections, another focusing is performed, this time in the elevation direction using unique delays in relation to the data from sections A, B and C, using a similar technology that was used earlier to focus beams in the azimuth plane with applying delays along the drive circuits in the column. This process can be considered as two-stage beamforming, where the first stage provides for the development of scan lines from sections A, B and C, and the second stage uses this data to develop the focus in the elevation plane. Elevation focusing is achieved in the receiver by applying digital delays. This technology not only provides elevation-plane focusing, but also allows dynamic focus changes. In this case, the focal length can be adjusted as a function of time, allowing the focus to move in the elevation plane along with the ultrasonic beam.

[0137] Although the process described in connection with FIG. 13A and 14 may require three transmissions and receptions, the first and second transmission and reception of signals from sections A and C may be combined into one operation. In some embodiments of the present invention, it is possible to simultaneously transmit from both the top and bottom of the transducer, where the delays at the top and bottom of the column are identical. The second transmission is made from the central part with delays different from those used in the first and/or second transmission.

[0138] In some embodiments of the present invention, the top section, center section, and/or bottom section may be divided into one or more subsections, each of which contains a number of rows for transmitting pulses and receiving a signal. In some embodiments of the present invention, each subsection may be used to generate multiple scan lines in a manner similar to that described herein.

[0139] In some embodiments of the present invention, the array of transducer elements may be divided into more than three lanes, such as 4, 5, 6, 7 or more lanes. In some embodiments of the present invention, the scan lines in each band may be scanned sequentially or simultaneously. In some embodiments of the present invention, simulcasting provides scanning lines from bands symmetrical to the center band. In some embodiments of the present invention, the delays for elements in the same column are identical for sections actuated simultaneously.

[0140] Elevation focusing can also be facilitated by additionally applying a lower voltage amplitude to part of the two outer transducer sections relative to the rest of the transducer.

[0141] In some embodiments of the present invention, a unique programmable delay in the elevation direction is implemented for each element of all columns. Assume that all N columns receive excitation signals that are delayed relative to each other. This may generate additional delays, further increasing the delay along the column of elements, and each element in the column may have a different delay than the delay for neighboring elements in the same column. One example of a delay profile is shown in FIG. 18V. The delay for all columns in the elevation direction can be the same. In one of the embodiments of the present invention, the delay is symmetrical, and its maximum falls on the central element when focusing in the elevation plane. The amount by which the delay between the outer and center elements differs determines the focal length.

[0142] A delay profile according to some embodiments of the present invention is shown in FIG. 18B, where the relative delay at the column edges may be denoted as 0 RD or 0 ns. For elements in rows 1 to R22, this delay relative to the delay in row 0 can be denoted as α ₁ RD and so on, as shown in FIG. 18B if the delays are desired to be symmetrical about the center element. Relative delay (RD) is programmed as α ₁ , α ₂ etc. Therefore, the delay profile can be added along the column, where the delay can be related to the delay at the edge of the columns. It should be noted that the relative delay profile may be identical for other column elements. In other embodiments of the present invention, the delay profile may be asymmetrical with respect to the central element, and it may be arbitrarily programmed. In some embodiments of the present invention, the delay varies in the range of 25-1000 ns. In some embodiments, implementation of the present invention can be programmed with different delay ranges within 10-5000 ns. In some embodiments of the present invention, the delay is in the range of 50-500 ns.

[0143] A procedure for obtaining a scanline using systems and methods according to some embodiments of the present invention is shown in FIG. 15. In some embodiments of the present invention, the reflected signal is received by the converter, after which this signal is converted to voltage and amplified, and then digitized using an analog-to-digital converter (ADC). These received signals are also known as RF signals (radio frequency signals). These RF signals can be delayed by τ _n (for example, τ ₁ , τ ₂ , τ ₃ , τ ₄ ...) and summed to form scan lines, for example, A1, A2, etc., as shown in Fig. 14 In some embodiments of the present invention, the signals are delayed and weighted with coefficients and then summed to form scan lines.

[0144] In some embodiments of the present invention, focusing the beam in the receive direction uses more than one RF signal in the azimuth (Y) direction, for example, S1, S2, etc., which are digitized output samples, known as RF- signals. In some embodiments of the present invention, the RF samples are delayed, for example, with a delay profile in the Y direction, and the resulting signal may be weighted and summed to obtain a scanline.

[0145] As shown in FIG. 14, in successive transmit and receive operations, scan lines A1 and A2 and additional scan lines using section A can be obtained. In some embodiments of the present invention, an image frame may include multiple scan lines, for example 100 or even more to obtain accurate scan of the rendered target area. A similar procedure can be used to obtain scan lines using section B and section C. The scan lines from sections A, B and C are developed using a first level beamformer, which beamformer creates scan lines using a certain algorithm, which in the described embodiment implementation of the present invention uses the signal delay and summation method described above. A synthetic aperture, a second-level beamformer, is then used to achieve focusing in the elevation plane, as shown in FIG. 16. In some embodiments of the present invention, these transmissions focus on a single elevation angle (0 degrees, 10 degrees, 20 degrees, 30 degrees, etc.), which reduces local out-of-plane noise outside the elevation plane and contributes to higher image quality. .

[0146] In one of the specific embodiments of the present invention, which is illustrated in FIG. 16, the focusing/beamforming of the second stage uses beam data (ie, scanline data) obtained from: A1, B1, and C1; A2, B2 and C2; A3, B3 and C3; etc., which are delayed, weighted, and summed to produce the final output beam, resulting in focusing in the elevation plane. In this embodiment of the present invention, the X-axis is the tilt axis.

[0147] In contrast to the mechanical lenses described herein, when using synthetic lenses, the focal length can be programmed into the beamformer electronically. In some embodiments of the present invention, the described process may require a number of transmissions and receptions (for example, one transmission and reception from the Nth number of lines to form the A1 scan line) to generate the scan line from any sections of the converter, for example, sections A, B and C A frame requires R scan lines scanning the entire rendered area. Also, in this case, three separate frames A, B, and C are needed. In some embodiments of the present invention, a high frame rate in an image is desirable. A frame may include a plurality of scan lines. In this case, if the number of transmissions and receptions can be reduced, and the number of scan lines that can be expanded remains the same, then the frame rate will be increased. In some embodiments of the present invention, an increased frame rate can be achieved by combining transmission and reception from two sections (eg, A and C). Because these regions are symmetrical about the central region, the required delays, as shown in FIG. 15 may be identical for areas A and C. By combining these two areas into a single combined area for transmitting and receiving signals, the frame rate can be increased by 150%. The central region B may require delays different from those used in the first transmission for regions A and C. In some embodiments of the present invention, scan lines such as A1, B1, C1 and other lines of this kind are formed along the azimuth plane. During the second beamforming operation, data from the first level beamformer can be used, and by applying techniques similar to those illustrated in FIG. 15 and 16, focusing in the elevation plane can be achieved. In some embodiments of the present invention, a 2D scan may start at one side of the strip, such as column N, and end at the other end, such as column 1. Thus, frame A can be obtained by sweeping rows A1, A2, AN… in order. By following this sequence for frame B, which is the frame following frame A in time, the target can also move. To minimize the influence of motor artifacts, beamforming can be performed by alternating scan lines for different frames, such as A1, B1, C1, A2, B2, C2, etc. When A and C are combined in such a way that transmission and reception operations can be performed simultaneously, the combined area including areas A and C may be called a D area, and the scan lines D1, D2, etc. A non-limiting example of a sweep sequence is D1, B1, D2, B2, and so on. This can contribute to minimizing the sensitivity to the movement of the rendered target.

[0148] In some embodiments of the present invention, the number of rows used to form sections A, B and C can be programmed. The number of rows may be adjusted depending on which anatomical organs are being imaged and may be set using settings in the user interface, such as anatomical data or patient information.

[0149] In some embodiments of the present invention, an electronic synthetic lens provides dynamic focusing and dynamic aperture adjustment. For example, in the near field, the weights for A and C may be minimal and gradually increase with depth, resulting in a change in aperture.

[0150] In some embodiments of the present invention, sections (eg, A and C) undergo apodization during transmission and reception. Apodization can be achieved by pulse width modulation (PWM) of the transmit excitation (Tx) waveform. A non-apodized excitation pulse is characterized by a nominal pulse duration. By changing the pulse duration, for example, by decreasing it, the sound pressure at the output of the pMUT can be reduced. In some embodiments, implementation of the present invention, apodization is the convergence of the weight values of the elements as they move away from the center of the transducer to its edges. This can reduce sidelobes and provide higher quality images. By applying apodization to the described procedure, signal loss beyond the elevation plane can be reduced. In FIG. 10A-10B show an exemplary implementation of elevation direction apodization using a pMUT array. Each pMUT element in the array has three pins. In this embodiment, the pMUT elements can be programmed with varying polarization intensities. A pMUT array, such as shown in FIG. 10A can be polarized using different polarization directions for the membranes controlling the piezo material and different polarization intensities per row. In FIG. 10B shows examples of lattice shift compounds after polarization. In some embodiments of the present invention, the same principle applies to pMUT elements provided with two pins, for example, pin O and pin X.

[0151] In some embodiments, implementation of the present invention, apodization can be provided through the use of multi-level excitation transmission, for example, 3-, 5- or 7-level excitation. By selecting different levels of excitation signal, apodization can be achieved by supplying transmit excitation signals with varying amplitude, where the signal amplitude for the elements located closer to the edge will be less than for the central elements of the transducer. In this example, all elements in the outer rows may have lower drive voltages than those in the center rows, and through digital decoding and selection, specific drive levels may be available to generate multilevel output signals. An example of three-level decoding is shown in FIG. 22.

[0152] In some embodiments, implementation of the present invention, apodization is implemented by using smaller piezoelectric elements at the edges compared to elements at the center of the transducer aperture.

[0153] In some embodiments of the present invention, the transducer elements are arranged as shown in FIG. 13A in the top section A, the bottom section C, and the middle section B. As can be seen in FIG. 13B, in each of these sections, i.e. sections A, B and C, two adjacent elements in a row are electrically connected to each other in a transmit and/or receive operation, essentially converting an N-line (rows in this case equivalent to columns) converter to an N/2-line converter. During a transfer operation, the top and bottom sections of each row may be connected to one channel and the middle section to another channel. Thus, to serve N/2 rows, N channels are needed. During the transfer operation, all elements can be actuated, and through the use of all elements of the transducer, maximum transfer pressure can be created. Focusing in the azimuth direction can be achieved by changing the relative delay between the rows or columns by the transmission channels. During the receive operation, the elements may be connected as shown in FIG. 13B, and they can be focused in the azimuth direction. Elevation focusing may be performed using a beamforming operation using the results of a first level beamformer, as described in connection with FIG. 13A. Transmission and reception operations using transducer elements connected as shown in FIG. 13B may take advantage of a single transmit and receive operation using the entire converter to provide maximum signal-to-noise ratio and high frame rates. The signal-to-noise ratio may be higher than in the case illustrated in FIG. 13A, where each of the bands can be individually selected for drive, and the columns in each band share the same transmission drive scheme(s) since all elements are involved. In addition, motor artifacts can be reduced more quickly with the transducer shown in FIG. 13B than with the converter shown in FIG. 13A.

[0154] In some embodiments of the present invention, programmable delays for one or more columns may be generated in the elevation direction. In some embodiments of the present invention, it is contemplated that if all N columns receive drive signals that are delayed relative to each other, then additional delays may be generated, further increasing the delay for elements in the same column. In some embodiments of the present invention, each element in a column may have a delay different from the delay of the neighboring element/elements in the same column. An example delay profile is shown in FIG. 18V. The effective delay for a lattice element τ _i,j can be the sum of the group column delay, τ _j , and the individual row delay, τ _i , which is given by:

, where in some embodiments of the present invention, the delay τ _j , τ _i , can be defined as follows:

[0155] In equations (1)-(3), the transmission focal point is at position (x, y, z), and for the element at position x _j , y _{i ,} the delays can be calculated independently of each other. The variable c denotes the accepted speed of sound in the propagation medium. It should be noted that in the case of ideal undivided focusing, the delay for the transducer element, τ _i,j , can be calculated as follows:

It should be noted that in some embodiments of the present invention, the assumption of separability of delays in azimuth and elevation is not perfect, and the largest errors in the delay profile are observed at the outer elements of the focusing aperture. However, for embodiments with small deflection angles and/or large f/number (where f/number is the ratio of focal length to aperture diameter), this separability assumption can provide satisfactory results and ease of implementation electronically.

[0156] The delay for all column elements in the elevation direction (eg, the same row) may be the same. This delay can be symmetrical, and it reaches its maximum at the center when focusing in the elevation plane. The amount of delay may determine the focal length.

[0157] In some embodiments of the present invention, a programmable delay in the elevation direction for all columns can be implemented. Let us assume that N columns receive excitation signals that are delayed relative to each other. This may generate additional delays further increasing the delay along the elements in a column, where each element in a column may have a delay different from that of an adjacent element in the same column. Asymmetric delays with respect to the center element in the column can also be provided. In some embodiments, implementation of the present invention, it is desirable to provide deviation of the beams in the elevation plane, and the delays for the elements in the column should be generated so that each element of the column is characterized by a fixed delay increment relative to the neighboring element.

[0158] In some embodiments of the present invention, programmable delays in the elevation direction can be implemented, and these delays can be the sum of two delays, for example, a coarse linear delay and a fine random delay. A coarse linear delay for elements in a column can also be useful for beam deflection. For beam deflection, the element at the bottom of the column may have a lateral delay relative to the element at the top of the column, with elements between said elements having linearly interpolated delays. The delays increase as the deflection angles increase. In addition, precise delays along the elements in a column can be useful for focusing the beam in the elevation direction. For example, the beam can be focused if the center element in the row has delay values that are higher and decrease symmetrically on both sides of the center element. Small delays result in beams with longer focal lengths (eg, tens of nanoseconds), while large delays result in beams with shorter focal lengths (eg, hundreds of nanoseconds to microseconds). In some embodiments of the present invention, it is contemplated that if all N columns receive excitation signals that are delayed relative to each other, then elevation delays can be generated further increasing the lag along the elements in the column, with each element in the column being delayed. with two delays, for example, a coarse and a fine delay, wherein the coarse delay may be linear between adjacent elements and the fine delay may be arbitrary between adjacent elements. The linear delay along the elements of a column may vary from column to column, just as the exact delay along the elements of a column may vary from column to column. Therefore, the effective delay for a lattice element τ _i,j can be the sum of the group column delay, τ _j , the linear coarse row delay, τ _i,coarse , and the fine row delay, τ _i,fine , which is given by:

where the quantities τ _j , τ _i,coarse and τ _i,fine can be calculated as follows:

[0159] In equations (5)-(7), the transmission focal point is at position (x, y, z), and for the element at position x _j; y _i delays can be calculated independently of each other. The variable c denotes the accepted speed of sound in the propagation medium. In equation (6), the parameter y _min can be calculated by projecting the focal point (x, y, z) onto the 20-plane of the transducer and calculating the position of the transducer row with the minimum distance to the projected focal point. The coarse delay slope, Δτ, can be calculated so that the fine delay can be used to closely approximate ideal 2D delays.

[0160] One skilled in the art will appreciate that the methodology described above for calculating delays can provide an even more accurate approximation to the 2D focus delays of Equation (4) compared to the separate X-Y delays above. A more accurate delay calculation may come at the cost of additionally requiring a coarse delay clock, a fine delay clock, and a slightly larger number of register bits to implement different column delays. However, this method is easier to implement in an integrated circuit than a completely arbitrary two-dimensional delay with precise clock delays and interconnection for each individual element.

[0161] In some embodiments of the present invention, a cascaded array of on/off relays switches the clock input to the column from the Tx beamformer with an appropriate delay. This delay can then be distributed in the column by another clock whose frequency is programmable but synchronized with the Tx clock which generates the delay for the various drive circuits in the column. With regard to the symmetrical delay about the center element in the column, the chain of on/off relays generating delays ends at the center element of the column, and the delay profile can be symmetrical about the center, as shown in FIG. 19. The delays generated by the on/off relays can be routed to the proper points so that the element in row 0 has the same delay as the element in the last row, the element in the second row has the same delay as the second last element on the top side , etc.

[0162] In some embodiments of the present invention, the delays between adjacent elements in a column may be linear. The results presented in Table 1 and the elevation beam plots presented in FIG. 23A demonstrate the effect of using a linear delay profile in elevation versus a parabolic profile. The results presented in Table 1 quantify the beam opening angles (at -3 dB and -10 dB) on the unidirectional plots shown in FIG. 23A. As shown in FIG. 23A, one particular embodiment of the present invention discusses five different implementations of elevation focusing for a 2D transducer array: 1) No elevation focusing; 2) Perfect 2D focus; 3) With linear delays; 4) With piecewise linear delays; and 5) Sparse apodization. In the case of linear delays, the delays between adjacent elements along the column may be fixed with respect to each other, and the delay profile in elevation may be symmetrical about the center of the array, although this is not required. In a variant with piecewise linear delays, the delay profile can be divided into at least three segments, with adjacent elements in a given segment having a fixed delay relative to each other. This method improves the approximation of the parabolic delay profile by including a plurality of linear delay segments. The sparse apodization method reduces the number of active elements compared to other methods by activating and deactivating the elements so that the array functions similarly to a 1.5D transmission array. One example of such a sparse apodization method is shown in FIG. 23V. It should be noted that with this approach, the outlet pressure can be reduced compared to the full aperture option. Examples of different transducer deflection angles are shown in Fig. 44.

[0163] The results shown in Table 1 illustrate -3 dB and -10 dB beam angles for elevation beam plots with 0° azimuth deviation. These results indicate that the linear delay method is more efficient than the non-elevation focusing method and can provide performance similar to that obtained with the 2D perfect focusing method. The method with piecewise linear delays, as expected, turned out to be even more efficient in terms of obtained beam opening angles in comparison with the linear method. In terms of obtained beam opening angles, the sparse apodization method is more efficient than without focusing in elevation, but it is not as efficient as linear methods. . The reason for the insufficient efficiency of the sparse apodization method is most likely due to the fact that the step along the "rows" of the sparse lattice is reduced in comparison with other methods. The results from the elevation ray plots shown in FIG. 23A show that the beam plots using the linear delay and piecewise linear delay methods are similar to those using the 2D beam focusing down to -15 dB method. The sparse apodization method produces an asymmetric beam pattern due to lateral shifts in the rows, and this method produces the largest side lobes of any method considered. These methods also provide lateral stability (right drawing in FIG. 23A). These results indicate that the electronic elevation delay methods described above are a suitable alternative to phased array and linear array imaging in low cost battery powered ultrasound imaging systems.

[0164] Table 1 shows the results of focusing in elevation using various delay profiles, or the results without focusing in elevation. These results quantify the results presented in the 0° azimuth ray plots shown in FIG. 23A. In some embodiments of the present invention, each element in a column is provided with a dedicated drive drive circuit. In some embodiments of the present invention, each element driver includes a delay circuit driven by a clock, for example, TxB Clk. The delay circuit in one embodiment comprises a plurality of on/off relays shown in FIG. 17A. DIP relays (e.g. DFF1, DFF2, DFF3, DFF4, etc.) have a digital input starting at the bottom of a column, for example, row 0. In some embodiments of the present invention, TxA is a digital bit generated by a beamformer on transmission. The transmit beamformer may include circuitry that provides multiple digital bits per channel. As shown in FIG. 17A, two bits per channel are used. One digital bit is designated as TxA. The other bit is designated as TxB. For TxB or any additional bits, schemas identical to those attached to TxA, such as those shown in FIG. 17A. These two bits can be encoded to determine the drive voltage levels in the transmission drive circuits, as shown in FIG. 39B. In this case, TxA and TxB are digital signals that can be encoded to determine the signal levels at the output of the transmission drive circuit Tx. For example, if both TxA and TxB are zero, or the output level is Common, then the signal is grounded; if TxA=1 and TxB=0, then the output signal will be high (HI). This can be a positive voltage of 5 V or 10 V or, if necessary, a positive voltage with a different value. If TxA=0 and TxB=1, then the output signal becomes low (LO) or -5 V or -10 V, for example, when the Common value is 0 V. The TxA and TxB signals can be generated in the Tx beamformer using a high-speed a clock generator, designated as TxB CLK, which in one of the preferred embodiments may be a 200 MHz oscillator. The output signals with a delay at the output of the pulse generator Tx can be used to deflect or focus ultrasonic beams, as shown in Fig. 18A. In this case, it is assumed that in a linear imager, all elements in a row have the same delay. Each line element may contain two bits (eg, TxA and TxB) transmitted by the Tx beamformer. The bits for the following lines will be different and may be delayed depending on the need to deflect or focus the beam. These delays provided by the Tx beamformer may be provided along the azimuthal axis and may deflect or focus the beam in the axial direction. However, delays may also be needed in the elevation direction to deflect or focus the beam in the elevation plane. This may require separate delays for the elements in the column. One embodiment is shown in FIG. 17A. The TxA and TxB bits come from the Tx beamformer in the column. Each row contains two-position relays DFF1-DFFN, where the value of N is from 1 to 16 or 32 or more, if necessary. Input contact 1 of the DFF1 relay can be connected to TxA or TxB. Pin 1 of the two-position relays can be connected to a clock generator, which is designated as clkhi, and which is generated by a digital divider with a TxB clock generator as its input. The division is done by dividing by the value of M, where a digital input bus, designated Div Control and shown here as an 8-bit bus, can be used to determine the value of M, by way of non-limiting example. Two-position relays DFF1-DFFN, which create delays for input signals TxA/TxB, are shown in Fig. 17A, where A, B, and C are delayed versions of TxA and TxB. Their outputs may be connected to a MUX which selects one of these inputs as its output, this selection may be made using a decoder controlled by SELO, SEL1, etc., which may include F bits. For example, for row 0, it is provided that if all F bits are zero, then the port input marked one is selected as the output for the MUX. In the case where TxA is selected as the output signal, it is provided that if the value of F is a binary one, the port marked one will be selected and A will be connected to the MUX output. These digital outputs, two per channel in this case, can then be decoded as shown in FIG. 22 and used to drive the output signal of the pulse generator. This scheme can provide accurate delays relative to the incoming delays on the TxA and TxB bits for the elements in the column. Also, these delays can be unique to the elements in the column. In FIG. 17B shows one exemplary embodiment of the present invention where coarse delays can also be added for elements in a column. In this case, another divider may be provided that divides by the value N. An input clock generator TxB CLK may be provided where the value of M is less than or equal to the value of N, and these values are integers. The output of this divider, clklo, can be connected to the input of the DFF relay as shown in FIG. 17V. In this case, TxA or the output signal of the DFF relay (which is the delayed version of TxA) can be connected to MUX, and if the non-delayed version of the signal applied to the element in row 0 is selected, then it can then be connected to pin 2 of the DFF relay in row 1. If an element in row 1 requires a delay, then the MUX in row 1 can select the delayed version (pin 3 output of the DFF relay). This can be repeated for the next element. In this case, a delay can be added for all elements in the column, except for the element in row 0. This linear delay, applied to the elements in the column, can contribute to beam deflection. The circuits shown in Fig. 17A and 17B may also be combined to impart fine delay and coarse delay to all elements in the column. For example, this can be done by adding circuits to INT_TXA @ Row 0 and similar nodes in other rows where the fine delay circuits shown in FIG. 17A to add fine delays to these outputs, which are already delayed by the coarse delay generator. In FIG. 17C shows one preferred embodiment of the present invention for implementing coarse and fine delay for each element in a column. The TxA and TxB bits are labeled as TxA/B connections to pin 1 for MUX 1. If this input is selected by the control labeled UP, then TxA/B appears on the output of MUX 1. This signal can then be given a DFF relay delay using elk_lo. The on/off relay output can then be made available to MUX 2, and if that input is selected by MUX 2 (using a control such as no_lin_delay), then the MUX 2 output is connected to DFF1-N in the same manner as shown in FIG. 17A. Such a circuit design can provide accurate delay. Moving further up from the DFF output towards a MUX similar to MUX 1 but for the next row, this signal can then be given a delay, which is set by the DFF ON/OFF relay connected to it. The same process can be repeated in the vertical direction for other rows. This may provide a linear delay for the upstream elements along the column, for example from row 0 to other rows. In each row, the DFF1-N relay can add a precise delay for the elements in the column. The second input of MUX 1 and similar MUXs for all rows can be used to delay signals in a linear fashion, starting with the minimum delay at the top and ending with the maximum delay at the bottom (row 0). However, TxA/B can also be connected to pin 2 of clone MUX 1 in the last row. Thus, by using the control labeled UP on MUX 1 (and its equivalents in other rows), the delay can increase from bottom to top or vice versa.

[0165] FIG. 21 shows the pulse generator waveforms, i.e. the output signal of the transmission drive circuit after the delay and decoding for focusing in elevation, where the value of P1 indicates the output signal of the transmission drive circuit for element 1 with one delay; the value of P2 refers to the variant with two delays given to element 2; and the value P4 denotes the output signal of the transmission drive circuit of element 4 with four delays. In this case, only the coarse delay up the column is shown, and the fine delay is not shown.

[0166] In FIG. 18B shows the relative delay for elements in a column. In some embodiments of the present invention, the amount of delay determines the focal length. In some embodiments, implementation of the present invention, the initial delay for all columns may be different, and it is set depending on the required focusing along the azimuthal axis. The delay along the elevation axis can be arbitrary. For example, the delay may increase linearly from the bottom row to the top row of the transducer. In this case, the beam can be deflected in the elevation direction. If the delay is symmetrical with respect to the central element, then focusing is carried out in the elevation plane. Many other delay profiles are also possible, which provide the ability to focus and tilt the slice in elevation.

[0167] FIG. 19 shows non-limiting examples of the shape of the transmission drive pulses applied to the piezoelectric elements along the transducer column. In this embodiment, the transducer contains 24 piezoelectric elements in a column. Element P0 is a piezoelectric element in a specific column (eg column 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, etc.) in row 0; element P1 is a piezoelectric element in the same column as element P0 but in row 1; element P11 is located in the same column, but in row 11; element P22 is located in row 22, and element P23 is located in row 23. In this embodiment, element P0 is supplied with one pulse at a certain frequency. The same pulse is applied to the element P1, but with a delay t01 relative to P0. Similarly, the same pulse arrives at the element P11 with a delay t ₀₁₁ that is greater than the delay t ₀₁ . In this embodiment, the delays are characterized by symmetries about the central element P11. This means that the pulse period for P23 and P0 is essentially the same, the pulse period for P1 and P22 is essentially the same, etc., as shown in FIG. 19. In some embodiments of the claimed invention, the pulse (its duration, magnitude, shape and/or frequency) in the context of this document is the same for all elements in the same column. In some embodiments of the present invention, the relative delay and pulse rate in the context of the present invention is the same for all elements in two rows of a column, or the initial delay for the first element in a column may be different from the delay for a similar element in another column. In some embodiments of the claimed invention, the pulse in the context of this document is characterized by a different shape, and the waveform may include multiple pulses. Non-limiting examples of pulse shapes include one or more of square, bell, and sinusoidal. In some embodiments of the present invention, the delays, for example, t ₀₁ , t ₀₂ , t ₀₃ , ..., t ₀₁₁ are programmed and controlled electronically for all elements in all selected columns.

[0168] FIG. 20 shows the relationship between the delay columns. In this particular embodiment of the present invention, the delays are determined by the beamformer channel transmission delays. For example, delay t ₁₀ is the delay between element 0 in column 0 and element 0 in column 10. These delays are programmed into the beamformer for transmission and are electrically corrected to help focus the beam in the azimuth plane as shown in FIG. 12A as the xa-za plane. In some embodiments of the present invention, the delays between elements in a column are programmed separately to focus the beam or deflect the beam in the elevation plane shown in FIG. 12A as a ya-za plane. Delay t ₀₁ is one example of a delay between elements in the same column (eg, elements 0 and 1 in column 0 and elements 0 and 1 in column 10). In some embodiments of the present invention, the delays for the elements in a column are related to the initial delay that is set by the beamformer to transmit for that channel. In some embodiments of the present invention, the initial delay may be predetermined by the transmit beamformer or adjusted by the transmit beamformer.

[0169] FIG. 22 shows an example of the functionality of a pulse generator according to a specific embodiment of the present invention. In this embodiment, the output voltage level of the pulse generator is controlled by two digital inputs, namely IN1 (eg, TxA in Figs. 17A-17D) and IN2 (eg, TxB in Figs. 17A-17D). Based on the logic level of these two inputs, a resulting three-level output signal can be generated, where the value HVP0 denotes a positive high voltage, the value HVM0 denotes a negative low voltage, and the value XDCR denotes an effective zero level or 0V. In this embodiment of the present invention, five identically shaped pulse cycles are generated as the resulting output signal. In some embodiments of the present invention, the pulse pattern, frequency and/or number of pulses can be changed by changing the pulse pattern and/or frequency of the pulse pattern of IN1 and IN2. In some embodiments of the present invention, logic levels or logic encodings in the context of this document may include digital logic operations of one or more inputs. In some embodiments of the present invention, logical operations involve the use of one or more logical operators on one or more inputs selected from the group that includes: AND, NOT, OR, NAND, XOR, NOR, XNOR, or any other logical operations.

[0170] In some embodiments of the present invention, the cascade/chain of on/off relays switches the transmit clock to one or more columns from the transmit drive circuit for that column with an appropriate predetermined or programmed delay. In some embodiments of the present invention, this delay is then propagated in the column by another clock whose frequency is programmable but synchronized with the transmit clock, which generates the delay for the various drive circuits in the column. In some embodiments of the present invention, the on/off relay circuit generating the delay(s) terminates at the center element of the column, with the delay profile symmetrical about the center, as shown in FIG. 19. The delays generated by the on/off relays can be routed to the appropriate points in one or more columns so that the element in row 0 has the same delay as the element in the last row, the element in the second row has the same delay as the second with end element on the top side, etc.

[0171] In embodiments of the present invention, elevation focusing is provided using different delay profiles. Using a linear delay profile in the elevation direction, such that the delay gradually increases or decreases from the bottom of the column to the top of the column, allows the beam to be deflected in the elevation direction. On top of that, the additional curvature imparted to the beams while maintaining zero curvature at the ends of the column, in addition to the possibility of deflecting the beam, makes it possible to focus it. The theoretical delay linearization can be accurate enough to provide deflection and focusing, as well as to provide a cost-effective implementation of the embodiments of the claimed invention described herein.

[0172] FIG. 24A shows an ultrasound imaging system 1800 according to the present invention. As can be seen, the imaging system may include: a transceiver substrate 1802; and an ASIC chip 1804 electrically coupled to the transceiver substrate. In embodiments of the present invention, the transceiver substrate 1802 may include one or more piezoelectric elements 1806, each of the piezoelectric elements may be located on one or more membranes. In embodiments of the present invention, more than one piezoelectric element may be located on the same membrane.

[0173] In embodiments of the present invention, each of the piezoelectric elements 1806a-1806n may be provided with two or more electrodes, and these electrodes may be connected to drive/receive electronics located in the ASIC chip 1804. In embodiments of the present invention, each piezoelectric element (e.g., 1806a) may include an upper conductor electrically connected to conductor (O) (e.g., 1814a) and two bottom electrodes electrically connected to conductors (X, T) (e.g., 1810a and 1812a). In embodiments of the present invention, conductor 1810a may be electrically connected to DC bias (X) 1832a or ground, and conductor (T) 1812a may be connected to DC bias (T) 1834a or ground.

[0174] In embodiments of the present invention, the ASIC chip 1804 may include one or more circuits 1842a-1842n that are electrically coupled to one or more piezoelectric elements 1806a-1806n; and one control unit 1840 for controlling circuits 1842a-1842n. In embodiments of the present invention, each circuit (eg, 1842a) may include a transmission drive circuit (1813a); receiver amplifier (eg 1811a); a switch (eg, 1816a) with one terminal electrically connected to the (O) conductor (1814a) and another terminal that switches between the two conductors connected to the transfer drive circuit 1813a and the amplifier 1811a. In the transmission mode/process (Tx), the switch 1816a may connect the transmission drive circuit 1813a to the piezoelectric element 1806a such that a signal is transmitted to the top electrode of the piezoelectric element 1806a. In a receive (Rx) mode/process, switch 1816a may couple amplifier 1811a to piezoelectric element 1806a such that a signal is transmitted from the top electrode of piezoelectric element 1806a to amplifier 1811a.

[0175] In some embodiments of the present invention, the transmission drive circuit 1813a may include various electrical components. However, for brevity, the transmission drive circuit 1813a is represented by only one circuit. However, those skilled in the art will appreciate that the transmission drive circuit may be a more complex circuit with multiple functions. Electrical components for processing received signals may be connected to amplifier 1811a, although in FIG. 24A shows just one amplifier 1811a. In embodiments of the present invention, amplifier 1811a may be a low noise amplifier (LNA). In embodiments of the present invention, circuit 1842n may have a similar or similar structure to circuit 1842a.

[0176] In embodiments of the present invention, all DC biases (X) 1832a-1832n may be connected to the same DC bias or ground, i. all conductors 1810a-1810n (X) can be connected to a single DC bias or ground. Similarly, all DC offsets 1834a-1834n (X) can be connected to the same or different DC offset, i.e. all conductors 1812a-1812n (T) may be connected to a single DC bias or ground.

[0177] In embodiments of the present invention, conductors 1810, 1812, and 1814 (X, T, and O) may be connected to the ASIC chip 1804 using interconnect technology, such as copper bollard or bollard connection structures (such as the 1882 on 24B) indicated by arrow 1880. In embodiments of the present invention, the circuit components within the ASIC chip 1804 may communicate outside of the ASIC chip 1804 using interconnect 1830. In embodiments of the present invention, interconnect 1830 may be implemented using wire leads leading from pads on the 1804 ASIC to another pad outside of the ASIC. In embodiments of the present invention, other types of interconnects may be used in addition to wired pads, such as bumps or redistribution pins on the 1804 ASIC.

[0178] In embodiments of the present invention, the LNA amplifiers 1811 included in the circuits 1842 may be implemented outside of the ASIC chip 1804 as part of a receive analog front end (AFE). In embodiments of the present invention, one LNA may be located in the ASIC chip 1804, and the other LNA and Programmable Gain Amplifier (PGA) may be located in the AFE. The gain of each LNA 1811 can be programmed in real time, allowing the LNA to be part of the Depth Gain Compensation (TGC) required by the imager.

[0179] In embodiments of the present invention, the LNA amplifiers 1811 may be constructed using low voltage transistor technologies and therefore may be destroyed when subjected to the high transmission voltage required by standard type converters. Therefore, conventional systems use a high voltage transmit/receive switch to separate high transmit voltages from low voltage receive circuits. Such a switch can be expensive, bulky, use high-voltage (HV) integrated circuit technology, and degrade the quality of the signal sent to the LNA amplifier. By comparison, low voltages may be used in embodiments of the present invention, and therefore high voltage components of a standard type system may no longer be required. In addition, in the embodiments of the present invention, performance degradation due to the use of a conventional HV switch can be avoided by eliminating the conventional HV switch from the circuit.

[0180] In embodiments of the present invention, the piezoelectric elements 1806 may be connected to the LNA amplifiers 1811 in receive mode via switches 1816. The LNA amplifiers 1811 may convert the electrical charge in the piezoelectric elements 1806 generated 811 by reflected elastic waves exerting pressure on the piezoelectric elements into amplified voltage signal with low noise. The signal-to-noise ratio of the received signal can be one of the key factors determining the quality of the reconstructed image. Thus, it is desirable to reduce the inherent noise in the LNA itself. In embodiments of the present invention, the noise level can be reduced by increasing the slope of the transfer characteristic of the front end of the LNA amplifiers 1811, for example, by using a higher current in the front end. Increasing the current can lead to increased power dissipation and increased heat generation. In embodiments of the present invention, the pMUT elements 1806 can be driven at low voltages and located in close proximity to the ASIC chip 1804, and therefore the power saved by the low voltage pMUT elements 1806 can be used to reduce the noise level in the LNA amplifiers 1811 for a given total temperature rise, tolerable compared to conventional high voltage controlled converters.

[0181] In FIG. 24B is a schematic representation of an imaging assembly 1850 according to embodiments of the present invention. In embodiments of the claimed invention, the transceiver substrate 1852 and the ASIC chip 1854 may be similar to the transceiver substrate 1802 and the chip 1804, respectively. In conventional systems, the electronics for driving the piezoelectric transducers is typically located away from the piezoelectric transducers and connected to the piezoelectric transducers via a coaxial cable. In general, coaxial cable increases parasitic loading such as additional electrical capacitance on the electronics, and the additional capacitance results in critical performance degradation such as increased noise and reduced signal strength. For comparison, as shown in Fig. 24B, the transmission drive circuit or circuits 1862a-1862n (or equivalent circuits) can be connected directly to piezoelectric elements 1856a-1856n+i (or equivalent pixels) using a low impedance 3D interconnect mechanism (which is indicated by arrow 1880), such as copper bollards or 1882 solder bollards, or wafer splicing, or other techniques, or a combination of such techniques. In embodiments of the present invention, once the transceiver substrate 1852 has been combined with the ASIC chip 1854, the circuits 1862 may be located less than (or so) vertically away from the piezoelectric elements 1856. In embodiments of the present invention, any conventional device for matching impedances between the circuits 1862 excitation and piezoelectric elements 1856 may be unnecessary, which further simplifies the design and increases the power efficiency (coefficient of performance) assembly 1800 imaging. The impedance of circuits 1862 can be designed to meet the requirements of piezoelectric elements 1856.

[0182] In embodiments of the present invention, each of the piezoelectric elements 1806a-1806n, as shown in FIG. 24A may be electrically coupled to a corresponding one of the circuits 1842a-1842n located on the ASIC chip 1804. The signals at the input of the transmission drive circuits 1813a-1813n may be generated using circuits such as those shown in FIG. 17A-D but not explicitly shown in FIG. 24A and 24B. In embodiments of the present invention, such an arrangement enables the imager to generate three-dimensional images. Similarly, each of the piezoelectric elements 1856a-1856m, as shown in FIG. 24B may be provided with three terminals, labeled X, T, and O. The terminals from each of the piezoelectric elements may be electrically connected to a corresponding one of the circuits 1862a-1862m located in the ASIC chip 1854 using an interconnect means 1882. In addition, in embodiments of the present invention, a number of piezoelectric elements, such as 1856n-1856n+I, may be electrically connected to one common circuit 1862n. In embodiments of the present invention, the transmission drive circuit 1862n may be implemented as a single transmission drive circuit. In alternative embodiments of the present invention, the transmit drive circuit 1862n may be implemented with multilevel drive to facilitate implementation of various imaging modes.

[0183] Those skilled in the art would appreciate that ASIC chip 1854 may be characterized by any suitable number of circuits similar to circuit 1862n. In embodiments of the present invention, the control unit 1892 may be configured to configure the piezoelectric elements, either horizontally or vertically in a two-dimensional pixel array, configuring their length and putting them into a transmit or receive mode, or a polarization mode, or an idle mode. . In embodiments of the present invention, the transmit drive circuit 1813 may be implemented with multi-level drive, as shown in FIG. 22 and 39, wherein the output of the transmission drive circuit may have more than two output levels. In FIG. 39A shows one embodiment where the output level may be 0V, or 6V, or 12V. It should be understood that these voltages may be different, for example, they may be -5V, 0V, and +5V. The transmission drive circuit may also be a two-level drive circuit with a drive signal as shown in FIG. 38.

[0184] In embodiments of the present invention, lead lines 1882a 1882n may be signal conductors that are used to supply pulses to the electrodes (O) of piezoelectric elements 1856. Similarly, lead lines 1884a-1884n, 1886a-1886n, and 1888a-1888n may be used for signal transmission using piezoelectric elements 1856a-1856n+i. It should be noted that other suitable number of output lines may be used for signal/data transmission with the imager assembly 1800.

[0185] In embodiments of the present invention, each of lead lines (X) 1886 and lead lines (T) 1888 may be connected to ground or a DC bias pin. In embodiments of the present invention, digital control pin 1894 may be a digital control bus and include one or more pins that are necessary to control and access various functions in imager assembly 1800. These pins, for example, allow the 1854 ASIC to be programmable using communication protocols such as Serial Peripheral Interface (SPI) or other protocols.

[0186] In embodiments of the present invention, the piezoelectric elements 1806 (or 1856) and control electronics/circuitry 1842 (or 1862) may be implemented on a single wafer. In alternative embodiments of the present invention, the transceiver substrate 1802 (or 1852) and ASIC chip 1804 (or 1854) may be fabricated separately and brought together in a 3D interconnect technology, such as metallized interconnect technology, using pins 1882. In embodiments of the present of the invention, the interconnection technology can eliminate the effect of low productivity of multiplication, whereby the cost is reduced, and the output of the components is independently maximized.

[0187] In embodiments of the present invention, lead lines 1862a-1862n may be signal conductors that are used to supply pulses to the electrodes (O) of piezoelectric elements 1806. Similarly, lead lines 1864a-1864n, 1866a-1866n, and 1868a-1868n may be used to transmit signals using piezoelectric elements 1806a-1806n. It should be noted that other suitable number of output lines may be used to transmit signals/data using the imaging assembly 1800.

[0188] As noted above, the LNA amplifiers 1811 can operate in a charge-sensing mode, and each of them has a programmable gain that can be configured in real time, providing correction by changing the gain.

[0189] FIG. 25 is an exemplary diagram of a matrix array 2000 of m×n piezoelectric elements 2002-11 to 2002-mn in accordance with embodiments of the present invention. As can be seen, each piezoelectric element may be a two-terminal piezoelectric element (such as piezoelectric element 214 in FIG. 3A) and be characterized by having an electrode (O) (e.g., 2003-11) electrically connected to a conductor (O) (e.g. , 2004-11), and an electrode (X) electrically connected to ground or a DC bias voltage through a common conductor 2006 (X). In embodiments of the present invention, each signal conductor (O) may be controlled independently by a circuit element). In embodiments of the present invention, each conductor (O) (for example, 2004-mn) may be electrically connected to the transmission drive circuit of the circuit element, while all electrodes X (2006-1 1-2006-mn) of the piezoelectric element array may be connected to common conductor 2006 (X). In embodiments of the present invention, the array 2000 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnect mechanism such as m × n+1 bump contacts. In particular, m×n wires 2004-11-2004-mn (O) can be connected to m×n ASIC chip drive drive circuits via m×n bump contacts, and common wire 2006 (X) can be connected to the chip ASIC via a single bar contact. In embodiments of the present invention, such an exemplary arrangement as described herein is used to perform 3D imaging, wherein each piezoelectric element, including at least one piezoelectric subelement, can provide unique information in the array. In embodiments of the present invention, each piezoelectric element may be characterized by the presence of one or more membranes, and it can oscillate in a plurality of membrane operating modes and at different membrane frequencies. In embodiments of the present invention, each piezoelectric element 2002 may be driven by pulses that are characterized by voltage profiles 3300 and 3400 shown in FIG. 38 and 39.

[0190] In embodiments of the present invention, the O electrodes in each column (eg, 2003-11-2003-m1) may be electrically connected to a common conductor. For example, circuit elements in an ASIC chip may be electronically controlled such that the O electrodes in each column may be electrically connected to each other. In such a configuration, the electrodes O in each column can receive the same electrical pulse through a common transmission drive circuit or through a plurality of drive circuits with identical electrical drive signals in the transmission mode. Similarly, the O electrodes in each column can simultaneously transfer electrical charge to the common amplifier in receive mode. In other words, the piezoelectric element in each column operates as a linear block (or, equivalently, a linear element).

[0191] FIG. 26 is an exemplary diagram of a matrix array 2100 of n×n piezoelectric elements 2102-11 - 2012-mn in accordance with embodiments of the present invention. As can be seen, each piezoelectric element may be a three-terminal piezoelectric element and include O, X, and T electrodes. Thus, all electrodes X (X11 - Xmn) can be electrically connected to a common conductor 2106 (X). The T electrodes (eg, T11, T21, . A column of elements, for example, 2102-11 and 2102-21 - 2102-m1, when connected together as described in embodiments of the present invention, forms a line element or column. In embodiments of the present invention, each of the O electrodes 2103-11 to 2103-mn may be electrically connected to the transmission drive circuit of the corresponding circuit element in the ASIC via one of the O11-Omn conductors. In embodiments of the present invention, the array 2100 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnect mechanism such as m × n+2 bump contacts. In the ASIC, the transmission drive circuits connected to the O electrodes can receive decoded pulses to generate a multi-level output signal, as shown in FIG. 22. These pulses may be delayed for the elements in the column (as can be seen in FIGS. 17A-17D). In addition, delays can be created along the columns (as shown, for example, in Fig. 19).

[0192] In embodiments of the present invention, the O electrodes in each column (eg, 2103-11 - 2103-m1) may be electrically connected to a common conductor. In such a configuration, the electrodes O in each column can receive the same electrical impulse through the common transmission drive circuit in the transmission mode. Similarly, the O electrodes in each column can simultaneously transfer electrical charge to the common amplifier in receive mode. In other words, the piezoelectric element in each column operates as a linear block. In embodiments of the present invention, each of the O electrodes in the column may be connected to a dedicated transmission drive circuit, wherein the input signals of the transmission drive circuits for all elements in the column will be identical, thus providing substantially identical output drive signals of the transmission on all piezoelectric elements during perform the transfer operation. Such a line element is electronically controlled on an element-by-element basis, since each element is provided with its own drive drive circuit. This provides advantages in terms of driving large size capacitive line elements, where each element has less capacitance, and time delays for elements in a column can be minimized. Embodiments of the present invention provide that, in receive mode, the charge of all elements in a column can be read by connecting it to an LNA amplifier, as is done with 2D imaging. In 3D imaging, the charge for each cell is read by connecting the O electrodes to each cell to the LNA during some operation in receive mode.

[0193] FIG. 27 is an exemplary diagram of a matrix array 2200 of m×n piezoelectric elements 2202-11 to 2202-mn in accordance with embodiments of the present invention. As can be seen, array 2200 may be similar to array 2100 with the only differences being that the X electrodes (eg X12-Xm2) in the column may be connected to a common conductor (eg 2206-1) and the T electrodes ( eg T12-Tm2) in a column can be connected to a common conductor (eg 2208-1). Thus, the X electrodes (or T electrodes) in the same column can have the same voltage potential during operation. In embodiments of the present invention, each of the O electrodes may be electrically connected to the transmission drive circuit of the corresponding circuit element in the ASIC via one of the O11-Omn conductors. In embodiments of the present invention, the array 2200 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnection mechanism such as m × n+2n bump contacts.

[0194] Compared to array 2100, array 2200 may include more bumps for connecting the T and X electrodes to the ASIC. In general, increasing the number of connections for T and X between the ASIC and the piezoelectric grid can reduce the impedance in the X and T conductors connected in parallel to ground or DC bias, as well as reduce crosstalk. Crosstalk is the mixing of the signals from one imaging element with the signals from another imaging element, which creates noise and reduces image quality. When the current flowing in the X and T lines causes a voltage drop across the piezo element, which should ideally not be subjected to such a voltage, parasitic electrical coupling can occur. In embodiments of the present invention, it is contemplated that when the piezo element is not transmitting or receiving under electronic control, the X, T, and O electrodes may be locally shorted. Alternatively, the non-working electrodes include grounded O electrodes, with the X electrodes remaining connected to other X electrodes in the array and the T electrodes connected to other T electrodes in the array.

[0195] FIG. 28 is an exemplary diagram of a matrix array 2300 of m×n piezoelectric elements 2302-11 - 2302-mn in accordance with embodiments of the present invention. As can be seen, the array 2300 may be similar to the array 2100 with one difference, which is that the piezoelectric element may be a five terminal piezoelectric element, i. each piezoelectric element may include a bottom electrode (O) and four top electrodes (two X electrodes and two T electrodes). In embodiments of the present invention, two X electrodes of each piezoelectric element may be connected column-wise in series, and all 2m×n X electrodes may be electrically connected to a common conductor 2306 (X). Similarly, the two T electrodes of each piezoelectric element can be connected column-wise in series, and all 2m×n T electrodes can be electrically connected to a common conductor 2308 (T). In embodiments of the present invention, each of the O electrodes may be electrically connected to the transmission drive circuit of the corresponding circuit element in the ASIC via one of the O11-Omn conductors. The ASIC may contain transmission drive circuits that are connected to the O nodes, and input signals to the transmission drive circuits may be delayed using the techniques and circuits described herein, for example, in conjunction with FIG. 17A-D. In embodiments of the present invention, the array 2300 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnect mechanism such as m × n+2 bump contacts.

[0196] In this embodiment, which is shown in FIG. 28, two subcells are connected to the X electrode and the other two subcells are connected to the T electrode. The X and T electrodes may be bias electrodes that are connected to DC voltage sources. The two elements connected to the X electrode may have different resonant properties. Together, these two sub-elements can have a wider bandwidth than either of these sub-elements taken separately. Two single-terminal subcells connected to the T electrode may both exhibit resonant properties similar to those connected to the X electrode. For example, one subcell connected to the X electrode and one subcell connected to the T electrode may have a resonant frequency or the center frequency is 2 MHz, and the remaining sub-elements can be characterized by a center frequency of 4 MHz. By combining these two sub-elements, the bandwidth of the constituent elements becomes wider. The use of X and T electrodes can also provide a different direction of polarization in the subcell/subcells, which increases the sensitivity of the cell/cells. However, in principle, a broadband element can also be made using only the X or T electrode, as shown in FIG. thirty.

[0197] In another embodiment, which is illustrated in FIG. 32, as in the previous example, the element uses two sub-elements, but in this case, each of the sub-elements can be equipped with two “O” terminals. Each sub-cell may have different dynamic characteristics, and since each sub-cell is provided with a unique adjustable drive terminal, i.e. electrode O, they can be electronically excited independently of each other.

[0198] FIG. 29 is an exemplary diagram of a matrix array 2400 of m×n piezoelectric elements 2402-11 - 2402-mn in accordance with embodiments of the present invention. As can be seen, grating 2400 may be similar to grating 2200, but with some differences, which is that each piezoelectric element may be a five-terminal piezoelectric element: one lower electrode (O) and four upper electrodes (two electrodes X and two electrodes T). In embodiments of the present invention, the two X electrodes of each piezoelectric element may be electrically connected to a conductor (e.g., 2406-1) in the direction along the column, and the two T electrodes of each piezoelectric element may be electrically connected to a common conductor (e.g., 2408-1) in the direction along the column. In embodiments of the present invention, each of the O electrodes may be electrically connected to the transmission drive circuit of the corresponding circuit element in the ASIC via one of the O11-Omn conductors. In embodiments of the present invention, the array 2400 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnection mechanism such as m x n+2n bump contacts.

[0199] FIG. 30 is an exemplary diagram of a matrix array 2500 of m×n piezoelectric elements 2502-11 - 2502-mn in accordance with embodiments of the present invention. As can be seen, the array 2500 can be similar to the array 2100 in that each piezoelectric element can be provided with one bottom electrode (O) and two top electrodes (T), but with some differences, which are that all electrodes are made of the numbers of the top two electrodes (T) of the piezoelectric elements along the column (eg 2502-11 - 2502-m1) can be electrically connected to a common conductor (eg 2508-1). In embodiments of the present invention, each of the O electrodes may be electrically connected to the transmission drive circuit of the corresponding circuit element in the ASIC via one of the O11-Omn conductors. In embodiments of the present invention, the array 2500 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnection mechanism such as m × n+n bump contacts.

[0200] In FIG. 31 is an exemplary diagram of a matrix array 2600 of m×n piezoelectric elements 2602-11 - 2602-mn in accordance with embodiments of the present invention. As can be seen, grid 2600 may have electrical connections similar to grid 2100, i.e. all electrodes X in the piezoelectric elements may be electrically connected to a common conductor 2606, and all electrodes T in the piezoelectric elements may be electrically connected to a common conductor 2608. The array 2600 may differ from the array 2100 in that the upper electrodes (X, T) of one piezoelectric element (for example, 2602-11) may have the same geometric shape as the top electrodes (X, T) of another piezoelectric element (for example, 2602-21), or a different geometric shape from these electrodes.

[0201] For the piezoelectric gratings 2000-2500, the piezoelectric elements in each of these piezoelectric gratings may be the same or different from each other. For example, the projection zones of the two upper electrodes of one piezoelectric element 2202-11 may have the same shape as the projection zones of the two upper electrodes of another piezoelectric element 2202-n1, or a different shape of the projection zones from these electrodes.

[0202] In FIG. 32 is an exemplary diagram of a matrix array 2700 of m×n piezoelectric elements 2702-11 - 2702-mn in accordance with embodiments of the present invention. As can be seen, each piezoelectric element may include two signal electrodes (O) and one common electrode (X). In embodiments of the present invention, each signal electrode (O) may be electrically connected to the transmission drive circuit of the corresponding circuit element in the ASIC chip. For example, the piezoelectric element 2702-11 may include two signal conductors OP1 and OP2, which may be electrically connected to respectively two circuit elements in the ASIC, each signal electrode may generate an electrical charge in the receive mode. In embodiments of the present invention, the array 2700 may be located on the transceiver substrate and it may be electrically coupled to the ASIC via an interconnect mechanism such as 2m×n+1 bump contacts. In embodiments of the present invention, all T electrodes in array 2700 may be electrically connected to ground or DC bias via a common conductor 2708 (T).

[0203] In embodiments of the present invention, the signal conductors (O) in the gratings, for example, as shown in FIG. 25-32 may be electrically coupled to the circuit element, where the circuit element may include a transistor switch similar to switch 1816 shown in FIG. 24A, i.e. the switch can switch between the transmission driving circuit and the amplifier, respectively, in the transmission and reception modes, so that the electrode O can generate elastic waves in the transmission mode and generate an electric charge in the reception mode.

[0204] In FIG. 33A shows an exemplary embodiment of an imaging system 2800 according to embodiments of the present invention. As can be seen, the imaging system 2800 may include a matrix array of piezoelectric elements 2802-11 - 2802-mn and circuit elements for controlling/communication with the array. In embodiments of the present invention, each of the piezoelectric elements 2802-11 to 2802-mn may include three electrodes: a first and second signal electrodes (O) and a T electrode (for illustration, the first and second signal electrodes (O) in each piezoelectric element are shown in Fig. 33 as the left and right electrodes O of each piezoelectric element). In embodiments of the present invention, all electrodes T in array 2800 may be electrically connected to ground or DC bias via conductor 2808 (T). In embodiments of the present invention, the first electrodes O of the piezoelectric elements in a column may be electrically connected to a common conductor (e.g., O11), and the second electrodes O of the piezoelectric elements in the same column may be electrically connected to another common conductor (e.g., O12). In this embodiment of the present invention, elevation deviation by electronic means may not be possible because, for example, all right electrodes O for elements 2802-11 to 2802-m1 can be connected to each other using an O12 conductor, and then connected to one of the circuits Tx excitation or receivers (Rx) 2816-1 and 2814-1. Instead of hardwiring together the O nodes for each element in the column using O12, each O node in the column can be connected to the corresponding Tx drive circuit, after which the delays of the signals that are fed into the transmit drive circuit can be adjusted so that the elements in the column can be characterized by a different delay, due to which focusing in elevation along the elevation axis for this column can be ensured. For this embodiment, this is shown in FIG. 33B, where switch 2812-11 is connected to pMUT element 2802-21 and switch 2812-1m is connected to O-terminal 2802-m1. The inputs of the Tx drive circuits 2816 are connected to circuits that generate the desired inter-element delay as shown in FIG. 17A-17D. For each O element electrode where electronic focusing is required, a separate Tx drive circuit, receive amplifier and/or switch may be required. In this example, other pMUT elements that require synthetic elevation focusing are also shown with separate transmit and receive electronics. They are shown in simplified form in Fig. 33B but represent the functional need for signal transmission and reception. This example provides that if the elements on O11-On1 do not require electronic focusing, then they can be connected, as illustrated, using wired connections. In embodiments of the present invention, each electrode of the first and second signal electrodes O in the receive mode can generate an electrical charge that can be processed by an appropriate circuit.

[0205] In embodiments of the present invention, as shown in FIG. 33A, the first set of conductors O11, O21, ..., On1 may be electrically connected to the amplifiers 2810-1 to 2810-n, respectively, and the electric charge generated in the column of the first electrodes O may be transferred to the corresponding amplifier through one of the conductors. A. In embodiments of the present invention, a second set of conductors O12, O22, ..., On2 may be electrically connected to switches 2812-1 through 2812-n, respectively, provided that electronic focusing along the elevation axis is not required. Otherwise, each element at O11 and On2 could be provided with a drive circuit Tx and an amplifier Rx connected to it via a switch, as shown in FIG. 33V. In embodiments of the present invention, each switch may be connected to a transmission drive circuit in a transmission mode/process so that a signal pulse can be transmitted to the column of second electrodes O of the piezoelectric elements. In embodiments of the present invention, each switch (eg, 2812-1) may be connected to a signal amplifier (eg, 2814-1) in a receive mode/process such that the electric charge generated in the second electrode column O of the piezoelectric elements (eg, 2801 -11 - 2802-m1) can be transferred to the amplifier. In embodiments of the present invention, piezoelectric elements 2802-11 - 2802-mn may be located on the transceiver substrate, while switches 2812-1 - 2812-n, transmission drive circuits 2816-1 - 2816-n, and amplifiers 2810-1 - 2810-n and 2814-1 - 2814-n may be located in the ASIC chip, and the transceiver substrate may be electrically connected to the ASIC chip through 2n+1 bump contacts. It should be understood that although the present explanation refers to FIG. 33A, jumpers may be used to provide elevation focusing electronically, where each electrode O is connected to a respective drive circuit Tx and an amplifier Rx via a switch as shown in FIG. 33V.

[0206] In embodiments of the present invention, a transmission drive circuit (for example, 2816-1) can transmit a signal to a column of piezoelectric elements (for example, 2802-11 - 2802-m1) through a conductor (O12), and at the same time an amplifier (for example, 2810-1) can receive an electric charge signal from the same column of piezoelectric elements (eg 2802-11 - 2802-m1). In such a case, each piezoelectric element (for example, 2802-11) in a column can receive a signal from a transmission drive circuit (for example, 2816-1) through one conductor (for example, O12) and simultaneously transmit an electric charge signal to an amplifier (for example, 2810- 1) through another conductor (for example, O11), i.e. the imaging system 2800 can simultaneously operate in transmit and receive modes. This simultaneous transmit and receive operation can be much more efficient for continuous Doppler imaging, where high blood flow velocity can be visualized, than pulsed Doppler.

[0207] In embodiments of the present invention, a line unit that refers to a column of O electrodes electrically connected to a common conductor may function as a transmit unit or a receive unit, or both. For example, electrical signals can be sequentially transmitted to conductors O12, O22, ..., On2 so that in transmit mode the linear elements will sequentially generate elastic waves, and in receive mode the reflected elastic waves can be processed and combined to form a two-dimensional image of the target organ. In another example, electrical charge signals in transmit mode can be simultaneously transmitted to the O12, O22, ..., On2 conductors, and at the same time, the reflected elastic waves can be processed using the charge generated by the O11, O12-On1 conductors to simultaneously transmit and receive ultrasound. in order to form a two-dimensional image. O12-On2 conductors can also be used to receive charge from piezoelectric linear elements in receive mode.

[0208] In FIG. 34A shows an exemplary embodiment of an imaging system 2900 according to embodiments of the present invention. As can be seen, the imaging system 2900 includes an array of piezoelectric elements 2902-11 - 2902-mn, and each piezoelectric element may include first and second signal (O) electrodes and a T electrode. In embodiments of the present invention, all of the T electrodes in the array may be electrically connected to one common conductor (T) 2908, and each row of first electrodes O may be electrically connected to one of the conductors O1-Om. If a linear imager without a synthetic lens is required, a mechanical lens will suffice. However, the same function may not be accomplished by shorting all the O nodes in the column, as shown in FIG. 34A. Instead, each node O can be driven by a drive circuit, and if all drive signals for the elements in a column have the same delay, then the same mode of operation as shown in FIG. 34A. However, when this is done electronically, as can be seen in FIG. 34B, different delays can be generated for the elements in the column and provide more accurate focusing in the elevation plane, as well as dynamic focusing in elevation, in which the focus changes its position depending on the depth as the signals travel towards the target. In embodiments of the present invention, as shown in FIG. 34A, each of the switches 2912-1 - 2912-n can switch between a transmission drive circuit (eg, 2916-1) and an amplifier (eg, 2914-1), which may be a low noise amplifier. In embodiments of the present invention, each of the O1-On conductors may be connected to one of the amplifiers 2910-1 - 2910-m, which may be low noise amplifiers.

[0209] In transmit mode embodiments of the present invention, a signal may be transmitted from a transmission drive circuit (e.g., 2916-1) to a column of second electrodes O through a conductor (e.g., O12) so that the column of piezoelectric elements can generate elastic waves as a linear block. In transmit mode, each switch (eg 2912-1) can switch to the corresponding drive drive circuit (eg 2916-1).

[0210] In embodiments of the present invention, imaging system 2900 may process reflected elastic waves in two different ways. In the first method, the amplifiers 2910-1 - 2910-n can receive electrical charge signals from the first O electrodes, i.e. each amplifier can receive signals from a number of first electrodes O. This method provides a two-view imaging/mode where, for a two-dimensional image, two-view imaging can provide orthogonal perspectives. In addition, this method may provide the ability to visualize in more than two dimensions. Biplanar imaging can be useful in many applications such as biopsy. It should be noted that in this method, the transmission and reception modes can be implemented simultaneously. In the second method, switches 2912 can be switched to amplifiers 2914 such that each amplifier can receive and process electrical charge signals from a respective column of second electrodes O.

[0211] Two-projection rendering can be performed by first creating an image along the azimuthal axis, giving delays to selected elements in the column. Elevation focusing can also be achieved by giving the elements in the column additional delays. During the subsequent operation along the orthogonal axis, a second image is created. This time the image is unfolded in the elevation plane by adding delays to the selected elements in the rows. Elements in the rows can be given additional delays to control the slice thickness in the azimuthal direction. Two images are then synthetically added to display the images in two orthogonal planes.

[0212] In embodiments of the present invention, the line block, which refers to the column (or row) of O electrodes electrically connected to the O conductor, may perform both the function of a transmit unit and the function of a receive unit, or both of these functions. Embodiments of the present invention provide that although the O1-Om conductors are aligned in perpendicular directions to the O12-On2 conductors, these directions can be programmed and corrected electronically. For example, the gain can be adjusted electronically in the 2910 and 2914 amplifiers, which have gain control pins. In embodiments of the present invention, the length of each line element (ie, the number of piezoelectric elements in each line element) can also be adjusted electronically. In embodiments of the present invention, this can be done by connecting all signal electrodes of each piezoelectric element to the corresponding nodes in the ASIC chip, with the ASIC chip programming the connection between the signal electrodes of the elements to be connected to each other, with transfer drive circuits or amplifiers depending from the situation.

[0213] FIG. 35A shows an embodiment of a piezoelectric element 3000 coupled to a circuit element 3001 according to embodiments of the present invention. As can be seen, the piezoelectric element 3000 may include: a first piezoelectric subelement 3021-1 and a second piezoelectric subelement 3021-2. The piezoelectric element 3000 may include: a bottom electrode (X) 3002 that is shared by the first and second piezoelectric subelements and connected to a conductor (X) 3006. In embodiments of the present invention, the first piezoelectric subelement 3021-1 may include a signal (O ) an electrode 3003 that is electrically connected to the amplifier 3010 via a conductor 3008. In embodiments of the present invention, the second piezoelectric subelement 3021-2 may include a signal (O) electrode 3004 that is electrically connected to the switch 3014 via a conductor 3012.

[0214] In embodiments of the present invention, the circuit element 3001 may be electrically coupled to the piezoelectric element 3000, and it may include two amplifiers 3010 and 3016, such as low noise amplifiers, and a transmission drive circuit 3018. In embodiments of the present invention, the switch 3014 may have one end connected to the electrode (O) 3004 via a conductor 3012, and the other end that can switch between the amplifier 3016 to switch to the receive mode and the transmit drive circuit 3018 to switch to the transmit mode. In embodiments of the present invention, amplifier 3016 may be coupled to other electronics to further amplify, filter, and digitize the received signal, even if the amplifier is used to symbolize the electronics. The transmission drive circuit 3018 may be a layered drive circuit and generate an output with two or more signaling levels. Signaling can be unipolar or bipolar. In embodiments of the present invention, the transmission drive circuit 3018 may include a switch that interfaces the input and output of the drive circuit under the control of the drive circuit's electronics, as not explicitly shown in FIG. 33A. Also not shown is the input signal to the drive circuit 3018, which may be delayed relative to such signals for another element in the same column, as shown in FIG. 17A-17D. Similarly, delays with respect to elements located in different columns can also be implemented, which allows electronic focusing along the azimuth axis and electronic focusing along the elevation plane.

[0215] In embodiments of the present invention, the signal of the transmission drive circuit 3018 may be a pulse-width modulation (PWM) signal, and by adjusting the pulse width on a chip-by-bit basis, a weighting function can be implemented with respect to the transmitted ultrasonic signal. This can be done, for example, by a slicing window function, whereby the slicing window function weights the transmission signal. In embodiments of the present invention, the weighting factors can be obtained by changing the duty cycle of the transmission signal, as occurs in the transmission of PWM signals. An operation of this kind provides the possibility of apodization to radiation, where the side lobes of the emitted signal are significantly weakened, which makes it possible to obtain an image of higher quality.

[0216] In embodiments of the present invention, the transceiver array may be located on the transceiver substrate and include an array of n × n piezoelectric elements 3600, and an n x n array of circuit elements 3001 may be located in an ASIC chip, and each piezoelectric element 3000 may be electrically connected to one corresponding array of n×n circuit elements 3001. In such a case, the transceiver substrate may be interfaced to the ASIC via 3n ² bumps. In embodiments of the present invention, each column (or row) of an array of piezoelectric elements may be controlled by a line element, as described in connection with FIG. 33A and 33B, as well as to FIG. 34A and 33B. For example, the same pulse can be simultaneously applied to a column of piezoelectric elements so that this column of piezoelectric elements can simultaneously generate elastic waves. It should be noted that each piezoelectric element 3000 of the n x n array of piezoelectric elements can be connected to a corresponding one element 3001 of the array circuit consisting of n × n circuit elements. Alternatively, each element in the column can be controlled individually by connecting the element node O to a dedicated Tx drive circuit as well as a dedicated amplifier. By adjusting the delays for the transmit driving circuit and the signal received from the LNA, focusing in elevation can be achieved in both the transmit and receive directions.

[0217] In embodiments of the present invention, the piezoelectric subelement 3021-1 may be in the receive mode throughout the operation period, while the piezoelectric subelement 3021-2 may be either in the transmit mode or in the receive mode. In embodiments of the present invention, the simultaneous implementation of the transmission and reception modes allows continuous Doppler imaging.

[0218] Embodiments of the present invention provide that when the transmission drive circuit 3018 transmits a signal to the electrode 3004, the power level of the elastic waves generated by the piezoelectric subelement 3021-2 can be changed using pulse width modulation (PWM) signals. This is important, for example, when switching from mode B to Doppler imaging mode increases the signal power transmitted to the human body, and if the power level is not reduced, this can lead to tissue damage. Typically, standard type systems for mode B and different Doppler imaging modes use different fast-regulating power supplies to provide a voltage difference to drive the transmission in the two cases so as not to generate excess power in the Doppler mode, for example. Unlike traditional systems, the power level in the embodiments of the present invention can be changed using PWM signals to transmit without the use of standard fast-regulating power supplies. Embodiments of the present invention require fast switching between Doppler imaging and B-mode imaging in order to form a joint image using the two modes. In embodiments of the present invention, the ground electrodes of the piezoelectric elements can also be separated from each other and connected to ground separately. In embodiments of the present invention, such independent grounding can reduce noise and result in faster settling time. In embodiments of the present invention, the power delivered can also be reduced by reducing the height of the electronically controlled transmission columns. It also facilitates the use of the same power supply for both Doppler and Mode B and satisfies the transmission requirements in each of these modes. It also provides the possibility of forming a "sub-image".

[0219] FIG. 36 shows a circuit 3100 for driving a plurality of piezoelectric elements according to embodiments of the present invention. In embodiments of the present invention, the circuit 3100 may be located in the ASIC chip, and the array (structured in rows and columns) of piezoelectric elements, which is located on the transceiver substrate, and the ASIC chip can be coupled to the transceiver substrate via bump contacts, and each pMUT element can be connected to the respective transmission drive circuit Tx and reception circuits via a switch, as shown in FIG. 35B, where electrode O is connected to switch 3014. As can be seen, circuit 3100 may include an array of circuit elements 3140-1 to 3140-n, with each circuit element capable of transmitting signals via the O and X electrodes of a respective piezoelectric element.

[0220] As shown in FIG. 36, each circuit element (eg, 3140-1) may include a first switch (eg, 3102-1), a second switch (eg, 3104-1), a third switch (eg, 3106-1), and a transmission drive circuit ( e.g. 3108-1). The output signal of the transmission drive circuit (for example, 3108-1) can be transmitted to the electrode O of the piezoelectric element through a conductor (for example, 3110-1). In transmit mode, each circuit element may receive a (drive) signal 3124 of the drive drive circuit via conductor 3122. Each of the second switches (for example, 3104-1), which may be a transistor switch and which may be controlled by control unit 3150, may be turned on. to signal transmission 3124 to a transmission drive circuit (eg, 3108-1) (electrical connections between control unit 3150 and other components in circuit 3100 in FIG. 36 are not shown). A transmit drive circuit (eg, 3108-1) can perform logic decoding, level shifting, buffering of the input signal, and forwarding of the transmit signal to the O electrode via a conductor (eg, 3110-1). Embodiments of the present invention provide that the first switch (eg, 3102-1) may be disabled in transmit mode.

[0221] In embodiments of the present invention, the control unit 3150 may determine which piezoelectric elements should be activated in the transmission mode. If the control unit 3150 decides not to activate the second piezoelectric element, then the first switch (for example, 3102-2) and the second switch (for example, 3104-2) can be turned off, while the third switch (for example, 3106-2) can be turned on. , as a result of which the electrodes O and X will have the same electric potential (i.e., a total zero excitation voltage is observed in the piezoelectric layer). Embodiments of the present invention may optionally provide third switches 3106.

[0222] In embodiments of the present invention, the first switch (for example, 3102-1) may be turned on in receive mode, whereby the electrical charge generated by electrode O may be transmitted via conductors 3110-1 and 3120 to amplifier 3128. Thereafter, amplifier 3128 may receive an electric charge signal (or, equivalently, a sensor signal) 3126 and amplify the sensor signal, where the amplified signal may be further processed to form an image. In receive mode, the second switch (eg 3104-1) and the third switch (eg 3106-1) can be turned off so that the received signal is not interfered with. It should be noted that the entire array of circuit elements 3140-1 - 3140-n can use one common amplifier 3128, which simplifies the design of the circuit 3100. In embodiments of the present invention, the electrodes X of the piezoelectric elements can be electrically connected to ground or DC bias voltage through conductors 3112 -1 - 3112-n, and the conductors 3112-1 - 3112-n can be electrically connected to the common conductor 3152.

[0223] In embodiments of the present invention, circuit 3100 may be connected to a column of piezoelectric elements (eg, 2002-11 - 2002-n1) as shown in FIG. 25. In embodiments of the present invention, a plurality of circuits similar to circuit 3100 may be connected to a plurality of columns of piezoelectric elements in the array shown in FIG. 30, and conductors 3152 may be connected to a common conductor (such as conductor 2006 shown in FIG. 25). In embodiments of the present invention, circuit 3100 may drive the column of piezoelectric elements shown in FIG. 25-32.

[0224] FIG. 37 shows a circuit 3200 for controlling a plurality of piezoelectric elements according to embodiments of the present invention. In embodiments of the present invention, the circuit 3200 may be located in an ASIC chip, wherein a row (column or row) of piezoelectric elements located on the transceiver substrate and the ASIC chip may be coupled to the transceiver substrate via bump contacts. As can be seen, circuitry 3200 may include an array of circuit elements 3240-1 to 3240-n, with each circuit element capable of transmitting signals via the O, X, and T electrodes of a respective piezoelectric element.

[0225] As shown in FIG. 37, each circuit element (eg, 3240-1) may include a first switch (eg, 3202-1), a second switch (eg, 3204-1), a third switch (eg, 3206-1), a fourth switch (eg, 3206-1), , 3207-1) and a transmission excitation circuit (for example, 3208-1). The output signal of the transmission drive circuit (eg, 3208-1) may be transmitted to the electrode O of the piezoelectric element through a conductor (eg, 3210-1). In transmit mode, each circuit element may receive a transmit drive circuit signal (or drive signal) 3224 via conductor 3222. Each of the second switches (e.g., 3204-1), which may be a transistor switch and which may be controlled by control unit 3250, may be enabled for signal transmission 3224 to a transmission drive circuit (eg, 3208-1) (electrical connection between control unit 3250 and other components in circuit 3200 in FIG. 37 not shown). The transmit drive circuit (eg, 3208-1) can perform logic decoding of the signal, shifting its level and buffering the output signal, and forwarding the transmit output signal to the O electrode via a conductor (eg, 3210-1). Embodiments of the present invention provide that the first switch (eg, 3202-1) may be disabled in transmit mode.

[0226] In embodiments of the present invention, the control unit 3250 may determine which piezoelectric elements should be activated in the transmission mode. If the control unit 3250 decides not to activate the second piezoelectric element, then the first switch (for example, 3202-2) and the second switch (for example, 3204-2) can be turned off, while the third switch (for example, 3206-2) and the fourth switch (eg 3207-1) can be turned on, so that the electrodes O and X (and T) will have the same electrical potential (i.e., a total zero excitation voltage is observed in the piezoelectric layer). In embodiments of the present invention, the third and fourth switches (eg, 3206-2 and 3207-2) may be optional. It should be understood that the three-level signaling and the transmission excitation circuitry implementing such signaling are not explicitly shown. Similarly, connections to X and T conductor switches such as 3206-2 and 3207-2 are shown in a simplified form.

[0227] In embodiments of the present invention, the first switch (e.g., 3202-1) may be turned on in receive mode, whereby the electrical charge generated by electrode O may be transmitted via conductors 3210-1 and 3220 to amplifier 3228. Thereafter, amplifier 3228 may amplify the electric charge (or sensor) signal 3226, and the amplified signal may be further processed to form an image. In receive mode, the second switch (eg, 3204-1), the third switch (eg, 3206-1), and the fourth switch (eg, 3207-1) can be turned off so that the received signal is not interfered with.

[0228] It should be noted that the entire array of circuit elements 3240-1 - 3240-n can use one common amplifier 3228, which simplifies the design of circuit 3200. In embodiments of the present invention, the electrodes X of the piezoelectric elements can be electrically connected to ground or a DC bias voltage via conductors 3212-1 - 3212-n, wherein conductors 3212-1 - 3212-n may be electrically connected to common conductor 3252. In embodiments of the present invention, the electrodes T of the piezoelectric elements may be electrically connected to ground or a DC bias voltage via conductors 3213 -1 - 3213-n, and the conductors 3213-1 - 3213-n can be electrically connected to the common conductor 3254.

[0229] In embodiments of the present invention, circuit 3200 may be connected to a column of piezoelectric elements (eg, 2102-11 - 2102-n1) as shown in FIG. 25. In embodiments of the present invention, a plurality of circuits similar to circuit 3200 may be connected to a plurality of columns of piezoelectric elements in the array shown in FIG. 26, and conductors 3252 may be connected to a common conductor (such as conductor 2106 shown in FIG. 26). In embodiments of the present invention, circuit 3200 may drive the column of piezoelectric elements shown in FIG. 25-32.

[0230] FIG. 27-37, conductors are used to connect one of the electrodes to the other electrode by electrical means. For example, electrodes 2006-11 - 2006-m1 are electrically connected to conductor 2006. In embodiments of the present invention, the conductors shown in FIG. 27-37 can be implemented in a variety of ways, for example, using a metallized connection layer deposited on a substrate and structured on which piezoelectric elements are located, or on another substrate, such as an ASIC, connected to said substrate.

[0231] In FIG. 38 and 39 are exemplary waveforms 3300 and 3400 for driving piezoelectric elements in transmission mode according to embodiments of the present invention. In general, a piezoelectric material can be susceptible to damage due to dielectric aging, but this aging can be delayed or prevented by using unipolar drive signals. The waveforms 3300 and 3400 represent the voltage potential between the O and X electrodes and/or between the O and T electrodes. (e.g. 2812, 2912, 3018, 3108, 3208, etc. is a unipolar transmission drive circuit) or multi-level (e.g., three-level) stepped signals 3400. The actual voltage amplitude typically ranges from 1.8 V to 12 .6 V. In embodiments of the present invention, a multi-stage signal 3400 or a signal with a large number of stages can reduce heat generation in the piezoelectric element, and it has certain advantages when used in certain imaging modes, such as Doppler imaging or harmonic imaging.

[0232] In embodiments of the present invention, the frequency of the pulses in waveforms 3300 and 3400 may vary depending on the desired nature of the signal and the need for frequency to which the pMUT-supporting membrane responds. In embodiments of the present invention, the waveforms may also be complex signals, such as linear or non-linear chirp signals, or other signals encoded using Golay codes.

[0233] In embodiments of the present invention, the drive circuits of the piezoelectric elements may be further configured such that the transmission output signal generated by the underlying membrane may be symmetrical in shape. In embodiments of the present invention, for each waveform pulse 3300 (or 3400), the rising edge of the pulse may be substantially symmetrical to the falling edge of the pulse about the center of the pulse. This symmetry reduces the harmonic content of the transmission signal, especially the second harmonic signal and other even order harmonics. In embodiments of the present invention, the pulse in waveform 3300 (or 3400) may be a pulse width modulation (PWM) signal.

[0234] FIG. 40 shows a transmit excitation signal waveform according to embodiments of the present invention. As can be seen, the signal 3500 generated by the transmit drive circuit may be symmetrical and unipolar, i.e. the value (H1) and the width (W1) of the maximum peak voltage are the same as the value (H2) and the width (W2) of the minimum peak voltage. In addition, the slope of the rising edge 3502 coincides with the slope of the falling edge 3504. In addition, the rise time W3 coincides with the fall time W4, with the fall time W4 indicating the time interval between the starting point of the fall and the reference voltage. And besides, the rising edge 3506 is characterized by the same steepness as the falling edge 3502.

[0235] During a transfer operation, a transfer drive circuit, such as circuit 3018 shown in FIG. 35 may be driven by an electrical waveform such as the signal shown in FIG. 38 and 39. In FIG. 41 shows output signals of various circuits in an imager assembly according to embodiments of the present invention. In embodiments of the present invention, waveform 3602 may be an output signal generated by a transmission drive circuit, such as 3018, and applied to a piezoelectric element, such as 3000. Embodiments of the present invention contemplate that since the piezoelectric element may have a characteristic bandwidth, it can produce a sinusoidal output signal as its resonant frequency. If the output signal of the transmission drive circuit connected to the O electrode of the piezoelectric element rises too slowly, it may not be able to charge the electrode to the required final value, which may cause the signals to output low, as shown in the example of waveform 3606, with the final the amplitude will be smaller than the waveform 3602. On the other hand, if the output of the transmission drive circuit stabilizes too quickly, the bandwidth of the output signal generated by the transmission drive circuit will be wider than the bandwidth of the piezoelectric element, and therefore excess energy may be dissipated in kind of heat. Therefore, in embodiments of the present invention, as seen in waveform 3608, the piezoelectric element can be charged at such a rate that it is fully charged, but not too quickly. In embodiments of the present invention, the waveform 3608, which represents the voltage potential at the top and bottom electrodes as a function of time, is closer in shape to the output signal of the transducer, and because the difference in shape is small, the input bandwidth and the output bandwidth are better matched. with each other, and there is also less energy loss in the form of heat. In embodiments of the present invention, the drive impedance of the transmission drive circuit is optimized to reduce power loss. In other words, the impedance of the transmission drive circuit is designed to drive the piezoelectric element in an optimal manner with respect to the heat dissipation and time constants necessary to effectively stabilize the voltage over a given period of time.

[0236] In embodiments of the present invention, the imager 126 may use harmonic imaging technology, where harmonic imaging refers to the transmission of elastic waves at the fundamental frequency of the membrane and the reception of reflected elastic waves at the frequency of the second harmonic or higher harmonics. In general, images based on reflected waves at the second harmonic frequency or higher harmonics are of higher quality than images based on reflected waves at the fundamental frequency. The symmetry in the transmission waveform can suppress the second or higher harmonic components of the transmission waves, and therefore the influence of these components on the second or higher harmonics in the reflected waves can be reduced, which improves image quality when using harmonic imaging technology. In embodiments of the present invention, to reduce the second or higher harmonics in the transmission waves, the waveform 3300 may have a 50% duty cycle.

[0237] FIG. 25-34, the gratings may include a plurality of linear blocks, with each linear block including a plurality of piezoelectric elements that are electrically connected to one another. In embodiments of the present invention, the line units may be driven by a plurality of pulses that are characterized by phase differences (or, equivalently, delays). By correcting the phases, it is possible to ensure the deviation of the resulting elastic waves by a certain angle, which is called beamforming.

[0238] FIG. 42A is a plot of transmission elastic wave amplitude versus transducer azimuthal position in accordance with embodiments of the present invention. If the piezoelectric elements in the array are aligned in two dimensions such that the piezoelectric elements in a column are connected in the Y direction and have a plurality of columns in the X direction, then the X direction is called the azimuth direction and the Y direction is called the elevation direction. As can be seen in FIG. 37A, the elastic transmission wave includes a main lobe and a plurality of side lobes. The main lobe can be used to scan target tissues and has a higher pressure amplitude. The side lobes have a smaller pressure amplitude, but they degrade the image quality, and therefore it is desirable to reduce their amplitude even more.

[0239] In some embodiments, implementation of the present invention, apodization in the context of this document involves the use of adjustable drive voltage, for example, with a lower weight near the edges and a fuller weight near the center of the ultrasonic pulses. Apodization can also be implemented by changing the number of elements along each column or row, or by this method alone, or in combination with other methods described herein.

[0240] FIG. 42B shows different types of windows for the apodization process according to embodiments of the present invention. In FIG. 42B, the X-axis represents the position of the piezoelectric element relative to the position of the piezoelectric element at the center of the active window, and the Y-axis represents the amplitude (or weight value given to the piezoelectric element). As can be seen, the rectangular window 3720 has no weighting for any of the transmission lines, i. e. they are all characterized by the same amplitude (i.e. symbolically designated unity). On the other hand, if the weighting function is implemented, as indicated by the Hamming window 3722, then the rows at the center have more weight than the rows at the edges. For example, to apply a Hamming window 3722 to a transducer cell, the piezoelectric elements in the leftmost column (which is labeled N in FIG. 42B) and the piezoelectric elements in the rightmost column (which is labeled N in FIG. 42B) can have the lowest weight, then how the piezoelectric elements in the middle of the column can carry the maximum weight. This process is known as apodization. In embodiments of the present invention, various types of windows may be used for weighing, although only one Hamming window 3722 is shown as an example. In embodiments of the present invention, apodization can be implemented in a variety of ways, such as different scaling of the drive level of the output signal generated by the transmit drive circuit for different lines using a digital-to-analogue converter (DAC), or by keeping the drive level at the same level, but with reduction the number of pixels in a line. The net effect will be to reduce the level of the side lobes through the use of apodization, with the transmit excitation weight varying depending on where in the excited transmit aperture a particular line is located.

[0241] In embodiments of the present invention, reducing the voltage of the pulses or waveforms can reduce the temperature at the surface of the transducer. Alternatively, for a given maximum acceptable surface temperature of the transducers, these low voltage transducers can provide high probe efficiency resulting in better image quality. For example, with regard to a probe with 192 piezoelectric elements, in order to reduce power consumption, elastic transmission waves can be generated using only a part of the probe (i.e., a part of the piezoelectric elements) and scanning the remaining elements sequentially in time using a multiplexer. Therefore, in conventional systems, only a portion of the transducer elements can be used at any given time to limit the temperature rise. By comparison, in embodiments of the present invention, a lower voltage probe allows more piezoelectric elements to be accessed simultaneously, allowing for higher image frame rates as well as improved image quality. A significant amount of power is also consumed in the receive path, where the received signal is amplified by LNA amplifiers. The imaging system typically uses a number of receive channels with one amplifier per receive channel. In embodiments of the present invention, the use of temperature data allows a number of receive channels to be disabled to save power and reduce temperature.

[0242] In embodiments of the present invention, apodization can be achieved by varying the number of piezoelectric elements in each linear block in accordance with the window function. In embodiments of the present invention, such a window approximation can be achieved by electronically adjusting the number of piezoelectric elements in a row, or by wiring the transducer array to the required number of elements. Apodization can also be achieved using a fixed number of cells, but with the excitation of these cells by an adjustable transmission drive voltage. For example, for apodization in the elevation direction, maximum excitation is applied to the central elements in the column, and lower level excitation signals are applied to the outer elements on both sides of the column around the central element of the column. Apodization can also be achieved by varying the polarization intensity of the elements based on their location in the column.

[0243] In general, the heat generated by the probe may depend on the pulse width in the transmission pulse/waveform. In general, to provide deeper penetration of elastic waves towards the target with a better signal to noise ratio (SNR), the piezoelectric element may require long trains of pulses. However, this degrades the resolution in the axial direction, and also contributes to the generation of more heat in the piezoelectric elements. Thus, in traditional systems, the number of emitted pulses is small, sometimes amounting to one or two. Because longer pulses can generate more heat, this makes them unsuitable for use in traditional systems. By comparison, in embodiments of the present invention, pulses and waveforms 3300 and 3400 may have significantly lower peak values, allowing long bursts, chirps, or other coded signals to be used. In embodiments of the present invention, the bursts of maximum width do not degrade resolution in the axial direction because the receiver performs matched filtering to compress the waveform to restore resolution. This technology provides a better signal-to-noise ratio and also allows signals to penetrate deeper into the body and provides better imaging of targets deep in the body.

[0244] In embodiments of the present invention, a layer of polydimethylsiloxane (PDMS) or other impedance matching material may be applied over the transducer elements. This layer can improve the impedance matching between the transducer elements and the human body, whereby the reflection or loss of elastic waves at the interface between the transducer elements and the human body can be reduced.

[0245] FIG. 25-34, more than one linear block can be obtained by connecting pixels in the Y direction (or in the X direction), where one linear block (or, equivalently, a linear element) denotes a plurality of piezoelectric elements electrically connected to each other. In embodiments of the present invention, one or more linear units may also be formed by connecting piezoelectric elements in the X direction. In embodiments of the present invention, the piezoelectric elements within a linear unit may be wired.

[0246] As described in connection with FIG. 24A, each piezoelectric element 1806 may be electrically coupled to circuit 1842, i. the number of piezoelectric elements on the transceiver substrate 1802 corresponds to the number of circuits 1842 in the ASIC chip 1804. In such a case, the electrical connections of the piezoelectric elements in each column (or row) can be implemented electronically, i.e. rigid conductors (eg 2006) connecting electrodes in a column (or row) are replaced by electronic switches. In other words, the piezoelectric elements in the linear imager/unit may be electrically connected to each other. With regard to the electronically adjustable linear imager, the linear imager/unit can be obtained by connecting each piezoelectric element of the 2D array array with a corresponding drive circuit (such as 1842) in the 2D drive circuit array, the drive circuits being spatially close to the pixels. . To obtain a line element, a plurality of drive circuits can be activated to drive a column (or row) of pixels, and the activation is carried out by electronic means. In embodiments of the present invention, the number of drive circuits in each linear imager/unit may be electrically modified by a control program and corrected electronically.

[0247] In embodiments of the present invention, the reduced electrical capacitance of each pixel can be efficiently driven by distributed drive circuits without the use of other equalization elements located between the drive circuit and the pixel, which eliminates the difficulty of driving ultra-high capacitance in a line. In the embodiments of the present invention, optimization of the drive circuits provides a rising-edge and falling-edge symmetry that improves the linearity of the output voltage, enabling harmonic imaging (this symmetry is described in conjunction with FIGS. 38 and 39.) aperture sizes, radiation apodization, and horizontal or vertical deflection control, all of which can improve image quality. In embodiments of the present invention, the configurable linear imager/unit can be electrically modified by a control program. For example, if fewer connected elements are required in the Y direction, then this number can be adjusted by means of software control and without the need to reassemble the control electronics or the piezoelectric grid.

[0248] In embodiments of the present invention, the design of each linear unit may provide for the presence of several sub-units with separate control of each sub-unit. The advantage of these sub-units is that they can help reduce the complexity of driving a large capacitive load for a line unit using a single external transfer drive circuit. For example, if instead of one line block including all the piezoelectric elements in a column, two line blocks are created, then two different transmission drive circuits (such as 2816) can be used and each transmission drive circuit can drive half the load of the entire line block. . In addition, even if only one drive circuit is used, driving the first half of the linear block and the second half of the linear block separately, it can improve the driving situation by connecting a reduced resistance to both ends of the linear block.

[0249] In embodiments of the present invention, both the length and orientation of the linear blocks can be adjusted. For example, as shown in FIG. 25-34, the line blocks can be positioned along either the X-axis or the Y-axis. For example, as shown in FIG. 35, O electrodes located along a column (e.g., 2003-11 to 2003-n1) may be electrically connected to form one line block, and O electrodes in other columns may be electrically connected to form an nth number of line blocks lined up. along the X axis. In particular, linear blocks that are aligned along the X axis include the nth number of electrodes O (2003-12 - 2003-1n), ..., (2003-n2 - 2003-nn). In embodiments of the present invention, the line units can be aligned in perpendicular directions by adjusting the electrical circuits in the ASIC chip.

[0250] FIG. 25-35, each piezoelectric element may include two or more top electrodes (X and T). In embodiments of the present invention, the piezoelectric layer under these top electrodes may be polarized in the same direction or in opposite directions. The multiple directions of polarization, combined with the appropriate applied signal electric field, can increase the transducer's transmit and receive sensitivity, as well as create additional resonances that provide a wider bandwidth.

[0251] FIG. 25-35, each grating may include one or more membranes located below the piezoelectric elements. In embodiments of the present invention, the membranes may have different modes of vibration. In embodiments of the present invention, one membrane may oscillate in the fundamental mode at a certain frequency, while the other membrane may oscillate at a different frequency, determined by the design of the membrane and the relative position of the electrodes with different directions of polarization. In embodiments of the present invention, multiple membranes may be driven by the same set of electrodes, and each membrane may have a different fundamental frequency from the others. In embodiments of the present invention, each membrane can respond to a wide range of frequencies, which increases its bandwidth. In addition, a transducer with different polarization directions can contribute to improving the sensitivity in transmission and reception, as well as obtaining a wideband transducer.

[0252] In some embodiments of the present invention, the X (or T) electrodes in the column may be electrically connected to a conductor. In embodiments of the present invention, these conductors may be electrically connected to a single common conductor. For example, the conductors may be electrically connected to a single common busbar so that all of the T electrodes in the array may be connected to ground or a common DC bias voltage.

[0253] In some embodiments of the present invention, each array may include piezoelectric elements arranged in a two-dimensional array (for example, as shown in Fig. 25-34), and the number of elements along the X axis may coincide with the number of elements along the axis Y. However, those skilled in the art will appreciate that the number of elements along the X axis may differ from the number of elements along the Y axis.

[0254] In embodiments of the present invention, an ASIC chip (such as 1804) coupled to a transducer substrate (such as 1802) may include temperature sensors that measure the temperature on the surface of the imaging device 126, which faces the human body during operation. In embodiments of the present invention, the maximum allowable temperature may be adjusted, and this adjustment may limit the functionality of the imaging device, since the temperature must not rise above the allowable upper level. In embodiments of the present invention, this temperature information can be used to improve image quality. For example, if the temperature is below the maximum allowed limit, then the amplifiers may consume additional power to reduce their noise level and improve the signal-to-noise ratio (SNR) to produce higher quality images.

[0255] In embodiments of the present invention, the power consumed by the imaging apparatus 126 increases as the number of line units driven simultaneously increases. It may be necessary to drive all of the line blocks in the imaging device 126 to complete the elastic wave transmission from full aperture. If only a few line units are fired to transmit elastic waves, wait, and receive reflected echo at the same time, then it will take more time to complete one cycle of firing all line units for a full aperture, which reduces the rate at which images can be captured per second (frequency frame changes). To increase this speed, a larger number of linear blocks must be excited at the same time. In embodiments of the present invention, the temperature information allows more lines to be driven by the imaging device 126 to increase the frame rate.

[0256] In some embodiments of the present invention, each piezoelectric element may be provided with one lower electrode (O) and one or more upper electrodes (X and T), and also be characterized by more than one resonance frequency. For example, each piezoelectric element 2502 shown in FIG. 30 may be provided with one bottom electrode (O) and two top electrodes, wherein the first top electrode and bottom electrode (O) can respond to a first frequency f ₁ while the second top electrode and bottom electrode (O) can respond to a second frequency. f ₂ which may differ from the frequency f ₁ .

[0257] In embodiments of the present invention, the electrical charge generated in the receive mode is transferred to an amplifier such as 1811, 2810, 2814, 2910, 2914, 3010, 3016, 3128, and 3228. The amplified signal can then be further processed by various electronic components . Thus, it will be apparent to those skilled in the art that each of amplifiers 1811, 2810, 2814, 2910, 2914, 3010, 3016, 3128, and 3228 collectively refers to one or more electrical components/circuits that process an electrical charge signal, those. each amplifier symbolically represents one or more electrical components/circuits for processing an electrical charge signal.

[0258] FIG. 43 is a schematic view illustrating an imager assembly 3800 according to embodiments of the present invention. As can be seen, the imager assembly 3800 may include: a transceiver substrate 3801 with piezoelectric elements (not shown in FIG. 38); an ASIC chip 3802 electrically coupled to the transceiver substrate 3801; a receive multiplexer 3820 electrically coupled to the ASIC chip 3802; 3830 AFE receiver (analogue input block); a transmission multiplexer 3824 electrically coupled to the ASIC chip 3802; and a transmission beamformer 3834 electrically coupled to the second multiplexer 3824. In embodiments of the present invention, the ASIC chip 3802 may include a plurality of circuits 3804 that are connected and configured to drive a plurality of piezoelectric elements on the transducer substrate 3801. In embodiments of the present invention, each circuit 3804 may include a receive amplifier 3806 (or simply an amplifier), such as an LNA, and a transmit drive circuit 3808 for transmitting a signal to a piezoelectric element, as well as a switch 3810 that switches between amplifier 3806 and circuit 3808 transmission excitation. Amplifiers may have a programmable gain and means for connecting it to the piezo elements to be sensed. The transmission drive circuits are provided with means for optimizing their impedance and with means for connecting to the piezoelectric elements to be driven.

[0259] In embodiments of the present invention, the receive multiplexer 3820 may include a plurality of switches 3822, and the AFE receiver 3830 may include a plurality of amplifiers 3832. In embodiments of the present invention, each of the switches 3822 may electrically connect circuit 3804 to amplifier 3832/disable circuit 3804 from amplifier 3832. In embodiments of the present invention, transmit multiplexer 3824 may include a plurality of switches 3826, and transmit beamformer 3834 may include a plurality of transmit drive circuits 3836 and other circuits not shown to adjust the relative delay between waveforms of different circuits. transmission drive circuits; and other circuits not shown for controlling the frequency and number of pulses for each of their transmission drive circuits. In embodiments of the present invention, each of the switches 3826 is activated during a transfer operation and connected to the circuit 3804, while the switches 3822 are turned off and the switch 3810 is connected to the transfer drive circuit 3808. Similarly, during a receive operation, switches 3826 are turned off while switches 3822 are enabled and switch 3810 is connected to amplifier 3806.

[0260] In embodiments of the present invention, switches 3810 may switch to transmit driving circuits 3808 in transmit mode and to amplifiers 3806 in receive mode. In embodiments of the present invention, a portion of the switches 3822 may be closed so that the respective circuits 3804 may be placed in the receive mode. Similarly, a portion of the switches 3826 may be closed so that the associated circuits 3804 may be placed in transmit mode. Since the switch part 3822 and the switch part 3826 can be closed at the same time, the imager assembly can simultaneously operate in both the transmit mode and the receive mode. In addition, the receive multiplexer 3820 and transmit multiplexer 3824 reduce the number of ASIC pins. In embodiments of the present invention, receive multiplexer 3829, AFE receiver 3830, transmit multiplexer 3824, and transmit beamformer 3834 may be included in circuits 202a or partially located in circuits 215a shown in FIG. 1B.

[0261] In embodiments of the present invention, each piezoelectric element may be provided with more than two electrodes, wherein one electrode may operate in transmit mode, generating elastic waves, while the other electrode may simultaneously operate in receive mode, generating electrical charge. This simultaneous implementation of transmit and receive modes improves Doppler imaging.

[0262] The movement of the rendered target may cause errors in the final image, and it may be necessary to reduce these errors. An example of such a movement is the movement of cardiac muscle tissue during imaging of the heart. To reduce the effect of said motion, it may be desirable to increase the frame rate. Therefore, increasing the frame rate while maintaining azimuth and elevation focusing and apodization can be of great importance. This can not only reduce jagged images, but also provide higher quality images using dynamic focus in the receiver by electronically changing the azimuth and focus with depth. Frame rate enhancement can be achieved in a two-stage beamformer as shown in FIG. 16 by operating the upper and lower section at the same time, which reduces the number of operations. In addition, scanning one full column, such as A1, B1 and C1, as shown in FIG. 14 before generating A2, B2 and C2 helps to minimize the effect of movement on the string. In addition, one scan line can be created using transmit and receive from all rows and columns in the involved section. However, the use of the parallel beamforming method [work titled "High Frame Rate Ultrasound Imaging Using Parallel Rayforming" by Tore Gruner Bjastad, Ph.D., Trondheim, January 2009, Norwegian University of Science and Technology] allows you to create many rays, for example, four. This can further improve the frame rate and reduce the effect of target movement. These methods can also create aberrations, but electronic methods for correcting them are known.

[0263] In some embodiments of the present invention, it is contemplated that although the electronic or electrical connections between individual elements shown in the figures herein are wired or physical connections, different digital connections can be used to enable programmable and more flexible digital communications. . In some embodiments of the present invention, such digital connections may include, but are not limited to, switches, plugs, gateways, connectors, and the like.

[0264] In some embodiments of the present invention, 3D imaging can be implemented using a 2D array of transducer elements as described herein. The reference to the azimuthal plane can be done by adjusting the delays of the elements in the column. This delay adjustment can be similar to that used in B-Mode rendering. Three-dimensional (3D) rendering can create volumes in 3D space and therefore may need to refer to the elevation plane. In one embodiment of the present invention, the ultrasonic beams can be deflected in the elevation plane to transmit from the entire transducer array. In this case, the beam is focused in the azimuth plane by adjusting the delays in the azimuth direction. Elevation adjustment can be achieved by adjusting the delay for the elements in the column according to the deviation of the beam in the elevation plane, for example, all column elements for all columns. In this embodiment of the present invention, a single scan line in the azimuth plane is obtained by transmitting from a plurality of columns, for example, 128 columns, where the bottom element of each column varies from another similar column as much as necessary to focus the beam in the azimuth plane. In the same embodiment of the present invention, an element in a column may have a constant delay that increases starting with an element in row 0, in accordance with the deflection of the beam in the elevation plane. These steps can be repeated multiple times, eg 100 times, with a different area for focusing the beam in the azimuthal plane, but with the same elevation delays to maintain the same beam deflection in the elevation direction. Thereafter, 100 elevation scan lines can be generated. This is followed by another 100 transmission events with azimuth focusing similar to that described above, but the elevation deflection is done using different delays for the elements in the column, resulting in different deflection angles. A variety of different deflection angles can be provided for volume scanning. Various deflection angles are shown in Fig. 44. The resulting echo can be received by the transducer and the image can be reconstructed. Parallel beamforming can be performed to increase the number of frames per second, and phase aberration correction is provided for higher image quality. Although some embodiments and examples of the present invention have been presented in the foregoing description, the subject matter of the claimed invention goes beyond the specific disclosed embodiments and covers other alternative embodiments and/or uses, as well as their modifications and equivalents. Thus, the scope of the appended claims is not limited to any of the specific embodiments of the present invention described above. For example, in any method or process described herein, the steps or steps of the method or process may be performed in any suitable order and are not necessarily limited to any particular sequence described. The various operations may be described as a plurality of individual operations performed in turn in a manner that facilitates understanding of certain embodiments of the present invention; however, the order of description should not be taken to imply that these operations depend on the order in which they are performed. In addition, the structures, systems and/or devices described herein may be implemented as integrated components or as separate components.

[0265] Certain aspects and advantages of various embodiments of the present invention are described for the purpose of comparing these embodiments. Not necessarily all such aspects or advantages are provided by any particular embodiment of the present invention. Accordingly, for example, various embodiments of the present invention may be implemented in a manner that provides or optimizes one or a number of advantages as described herein without the need to provide other aspects or advantages described or suggested herein.

[0266] In the context of the present invention, A and/or B includes one or more elements A or B and combinations thereof, such as A and B. It should be understood that although the terms "first", "second", "third" and etc. may be used herein to describe various elements, components, regions and/or sections, these elements, components, regions and/or sections should not be limited to these terms. These terms are only used to distinguish one element, component, area or section from another element, component, area or section. Thus, the first element, component, region or section described above may be referred to as the second element, component, region or section without departing from the teachings of the present invention.

[0267] the Terminology used in this document is used only for the purpose of describing specific embodiments of the claimed invention and is not intended to limit it. For the purposes of this document, the singular forms denoted by the definite and indefinite articles are also intended to include the plural forms, unless the context clearly dictates otherwise. It should also be understood that the terms "comprises" and/or "comprising" or "comprises" and/or "comprising" as used herein denote the presence of the specified features, areas, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, areas, integers, stages, operations, elements, components and / or combinations thereof.

[0268] In the context of the present invention and its claims, unless otherwise indicated, the terms "about" and "about" or "essentially" denote deviations that are less than or equal to +/- 0.1%, +/- 1%, +/ - 2%, +/- 3%, +/- 4%, +/- 5%, +/- 6%, +/- 7%, +/- 8%, +/- 9%, +/- 10 %, +/- 11%, +/- 12%, +/- 14%, +/- 15% or +/- 20% of the numerical value depending on the embodiment of the present invention. As a non-limiting example, the phrase "about 100 meters" means a range of 95 meters to 105 meters (i.e. +/- 5% of 100 meters), 90 meters to 110 meters (i.e. +/- 10% of 100 meters) or from 85 meters to 115 meters (i.e. +/- 15% of 100 meters) depending on embodiments of the present invention.

[0269] While preferred embodiments of the claimed invention have been illustrated and described herein, those skilled in the art should appreciate that such embodiments are illustrative only. Numerous alterations, variations and substitutions can be made by those skilled in the art without departing from the scope of the present invention. It should be understood that various alternatives to the embodiments described herein may be practiced. Numerous different combinations of embodiments of the present invention are possible, and such combinations are considered part of the claimed invention. In addition, all features described in connection with any one of the embodiments of the claimed invention presented herein can be easily adapted for use in other embodiments described herein. It is intended that the following claims define its scope, and that it covers the methods and structures included in the scope of this claim, and their equivalents.

Claims (29)

1. An ultrasound imaging system, comprising: a) an ultrasonic transducer comprising a plurality of piezoelectric micromachined ultrasonic transducer elements (pMUT), wherein the plurality of transducer elements are arranged in one or more rows and one or more columns, each of the plurality of transducer elements pMUT is provided with two or more leads, with two elements of the plurality of transducer elements pMUT are accessed simultaneously, the two elements being adjacent to each other in the same row of one or more rows, and the plurality of transducer elements comprising an upper section, a central section and a lower section, each containing the first number of rows and the second number of columns for transmitting and receiving ultrasonic pulses of the reflected ultrasonic signal, and the transmission and reception of ultrasonic pulses of the reflected ultrasonic signal from these sections are used to focus the reflected ultrasonic signal in the azimuth direction using the first beamformer, and while focusing in angle space is provided through the use of a second beamformer; And b) one or more circuits coupled to a plurality of pMUT transducer elements, the one or more circuits being electronically configured to allow: i) transmitting an ultrasonic pulse from an ultrasonic transducer; ii) receiving the reflected ultrasonic signal with an ultrasonic transducer; And iii) electronic control with the ability to focus the ultrasonic pulse or reflected ultrasonic signal in the elevation direction. 2. The ultrasound imaging system of claim 1, wherein each transducer element in the column is driven by at least one multilevel pulse that is generated by one or more circuits. 3. The ultrasound imaging system of claim. 2, in which the magnitude, width and shape of the pulse, pulse repetition rate, or combinations of these parameters of at least one multilevel pulse are electrically programmable. 4. The ultrasound imaging system of claim 2, wherein one or more of the pulse delivery delay or the number of pulses in at least one layered sequence is electrically programmable. 5. The ultrasound imaging system of claim. 1, wherein one or more of the plurality of transducer elements pMUT are polarized in two directions in their different areas, and the intensity of polarization varies depending on the location of one or more elements of the plurality of transducer elements pMUT in a row, and wherein each of the one or more elements of the plurality of pMUT conversion elements is provided with at least three pins. 6. The ultrasound imaging system of claim 5, wherein the polarization force is stronger for the central rows and weaker for the outer rows, thereby providing apodization in the elevation direction. 7. The ultrasonic imaging system of claim. 1, in which the regulation is carried out in real time. 8. The ultrasound imaging system of claim. 1, further comprising an outer lens mounted on top of a plurality of transducer elements, and the outer lens is configured to provide additional focusing in the elevation direction. 9. The ultrasound imaging system of claim 1, wherein the one or more circuits include one or more of the following circuits: a transmit drive circuit, a receive amplifier circuit, and a control circuit. 10. The ultrasound imaging system of claim 9, wherein the transmission drive circuit is configured to drive one or more of the plurality of pMUT transducer elements in the column and is driven by the transmission path signals, wherein the transmission path signals are electronically delayed relative to the delay applied with respect to other transmission channels driving another one or more of the plurality of pMUT transducer elements in different columns. 11. The ultrasound imaging system of claim 10, wherein one or more elements of the plurality of pMUT transducer elements in the column fire with substantially the same delay or different delays. 12. The ultrasound imaging system of claim. 11, in which the control circuit is configured to determine the relative delays for one or more elements of the plurality of transducer elements pMUT in the column, and the control circuit contains a coarse delay circuit configured to specify a coarse delay for the relative delays , and a fine delay circuit configured to set the fine delay for the relative delays. 13. The ultrasound imaging system of claim. 10, in which the transmission channel and additional transmission channels are configured to electrically control the relative delays between adjacent columns, and the control circuit is configured to set the relative delays for the first group of transducer elements in the column so that the first group of transducer elements in the same row exhibited a relative delay substantially similar to that of the second group of transducer elements in the initial row. 14. The ultrasound imaging system according to claim 10, in which the transmission channel and additional transmission channels are configured to electronically control the relative delays between adjacent columns, and the control circuit is configured to set the relative delays for the transducer elements in the column so that the first group of transducer elements in the same row was characterized by independent delays relative to the second group of transducer elements in the same row for other columns. 15. The ultrasound imaging system of claim 14, wherein the control circuitry is operable to electrically adjust the relative delays of the column so that they are symmetrical with respect to the transducer element in the center row of the column. 16. The ultrasound imaging system of claim 9, wherein the control circuitry is electrically adjustable to increase the relative delays in a column, thereby guiding the ultrasound beam in an elevation direction. 17. The ultrasound imaging system of claim. 9, wherein the control circuit is configured to control the relative delays by electrical means, which allows you to adjust the thickness of the slices in the elevation direction. 18. The ultrasound imaging system of claim 9, wherein the control circuit is configured to electrically control the relative delays between drive pulses for transducer elements located in the same column. 19. The ultrasound imaging system of claim. 9, wherein the control circuit is configured to electrically control the relative delays in the column so that they are symmetrical with respect to the transducer element in the center row of the column. 20. The ultrasound imaging system according to claim 9, in which the control circuit is configured to electrically control the relative delays so that they increase or decrease piecewise linearly in a column, and the number of piecewise linear delay segments is an integer of at least 2 . 21. The ultrasound imaging system of claim 9, wherein the control circuit is operable to electrically control the relative delays along the column by adding a linear delay and an arbitrary fine delay. 22. The ultrasound imaging system of claim 1, wherein the elevation focusing and elevation apodization are performed electronically to minimize errors due to motion. 23. The ultrasound imaging system of claim 1, wherein the ultrasound transducer has a bandwidth that is not effectively limited by signal loss due to mechanical lens loss. 24. The ultrasound imaging system of claim. 1, wherein one or more circuits are electronically configured to provide electronic control of apodization in the elevation direction.