Ultrasound probe device and method with programmable acoustic superstructure integrated at the front end of the probe

Abstract

The application discloses an ultrasonic probe device and method with a probe front-end integrated programmable acoustic superstructure, which comprises: an ultrasonic transducer module for transmitting and receiving ultrasonic signals; a programmable acoustic superstructure module arranged between an exit end of the ultrasonic transducer module and an acoustic window, for providing a two-dimensional spatial distribution or a three-dimensional stacked distribution of equivalent propagation time delay or equivalent phase modulation; a driving and control module for applying a control signal to each regulation and control unit of the programmable acoustic superstructure module to change the spatial time delay distribution or the phase distribution; an imaging and adaptive algorithm module for compensatory beam forming on echo data according to a current state, performing angle compounding, voxel-level compounding, volume data reconstruction and quality evaluation, and updating the control state in a closed loop when a quality index does not reach a preset threshold. The application realizes beam double-axis deflection and three-dimensional focusing under the condition that the probe is stationary, and reduces the dependence on a mechanical scanning mechanism.

Description

Technical Field

[0001] This application relates to the field of ultrasonic testing and imaging technology, specifically to an ultrasonic probe device and method with a programmable acoustic metastructure integrated at the probe front end. Background Technology

[0002] Current ultrasonic detection methods typically employ mechanical oscillation and translation or high-channel-count array electronic scanning to obtain a wider field of view or multi-angle information. Mechanical solutions suffer from large size and limitations in reliability and repeatability. High-degree-of-freedom array solutions are characterized by high cost, high power consumption, and complex size and packaging. Fixed-structure acoustic lenses or metasurfaces can improve focusing or form specific wavefronts, but it is difficult to achieve real-time programmable switching of angle and focus while the probe is stationary. Therefore, a solution is needed that can be integrated into the probe front end and electrically reconstruct the wavefront to achieve multi-angle coverage and more stable imaging quality without introducing mechanical movement.

[0003] Furthermore, existing 3D ultrasound imaging typically relies on mechanical scanning, two-dimensional area array electronic scanning, or external volume scanning mechanisms to acquire volume data. Mechanical scanning solutions suffer from structural complexity, large size, limited repeatability, and insufficient long-term reliability. While two-dimensional area array or matrix array electronic scanning solutions can achieve volume imaging, they usually require multiple independent channels, leading to high system cost, high power consumption, and complex packaging. External volume scanning mechanisms struggle to simultaneously achieve real-time performance, miniaturization, and probe integration. Existing fixed acoustic lenses or fixed-parameter metasurfaces typically only provide single focal length or single wavefront control capabilities, making it difficult to achieve biaxial deflection, 3D focusing, and volume scanning imaging in both azimuth and elevation directions when the probe is stationary. Summary of the Invention

[0004] The purpose of this application is to provide an ultrasonic probe device and method with a programmable acoustic metastructure integrated at the probe front end. Under the condition of probe stationary conditions, it realizes the biaxial deflection of the ultrasonic beam in the azimuth and elevation directions, three-dimensional spatial focusing and volume scanning control, supports volume data acquisition, three-dimensional reconstruction, multi-planar slice display and adaptive volume imaging, thereby reducing the dependence on mechanical scanning mechanism and high-channel two-dimensional area array electronic scanning.

[0005] In a first aspect, embodiments of this application provide an ultrasonic probe device with a programmable acoustic metastructure integrated at the probe front end, comprising: An ultrasonic transducer module is used to transmit and receive ultrasonic signals; A programmable acoustic superstructure module is disposed between the output end of the ultrasonic transducer module and the acoustic window. It is used to provide equivalent propagation delay or equivalent phase modulation for two-dimensional spatial distribution or three-dimensional stacked distribution to support the switching of azimuth deflection, pitch deflection, three-dimensional focusing and volume scanning states of the ultrasonic beam. The driving and control module is used to apply control signals to each pixel cavity of the programmable acoustic superstructure module and generate control commands according to the target deflection angle and target focusing depth to change the spatial time delay distribution or phase distribution formed by the programmable acoustic superstructure module. The imaging and adaptive algorithm module is used to perform compensated beamforming on the echo data based on the current state of the programmable acoustic superstructure module, and to perform angle compositing, voxel-level compositing, volume data reconstruction and quality evaluation. When the quality index does not reach the preset quality threshold, the control state of the programmable acoustic superstructure module is updated in a closed loop.

[0006] In one possible implementation, the programmable acoustic superstructure module is a pixelated variable sound velocity or variable time delay layer, which sequentially includes the following along the direction from the transducer to the object to be imaged: a base electrode layer, a pixel cavity array layer, and a top cover sealing layer. The base electrode layer is provided with multiple electrode units, which are connected to the drive and control module through leads; The pixel cavity array layer forms a multi-row, multi-column pixel cavity array. Each pixel cavity is filled with an electric field-responsive medium. Under the action of an applied electric field, the electric field-responsive medium changes its effective sound velocity or equivalent propagation constant, thereby changing the equivalent propagation time delay of the ultrasonic wave passing through the pixel cavity. Isolation walls for suppressing lateral crosstalk are provided between the pixel cavities. The upper cover sealing layer is sealed to the pixel cavity array layer to form a closed cavity.

[0007] In one possible implementation, the pixelated variable sound velocity or variable time delay layer adopts a two-dimensional array arrangement structure to simultaneously form spatial time delay gradients in the azimuth and pitch directions, so as to realize biaxial deflection control of the ultrasonic beam.

[0008] In one possible implementation, the pixel cavity array layer includes at least two stacked pixel cavities along the sound propagation direction, and the electrode units corresponding to the pixel cavities of different layers can be independently controlled.

[0009] In one possible implementation, the pixel center distance between adjacent pixel cavities in the pixel cavity array layer is less than half the wavelength of the ultrasonic wave in the coupling medium between the programmable acoustic superstructure module and the object to be imaged.

[0010] In one possible implementation, the electrode structure of the electrode unit adopts any one of the following: top-bottom opposed electrodes, coplanar electrodes, row-column interleaved addressing electrodes, or multilayer interconnection electrode structure. The driving and control module controls the pixelated variable sound speed or variable time delay layer by any one or more combinations of pixel-independent control, row and column control, two-dimensional block partition control, azimuth / pitch independent control, or hierarchical collaborative control.

[0011] In one possible implementation, the programmable acoustic superstructure module is configured as a detachable probe cap module; The imaging and adaptive algorithm module is also used to identify the type of the connected probe cap module and automatically select the imaging compensation parameters and calibration model corresponding to the type.

[0012] Secondly, embodiments of this application provide an ultrasonic imaging method with a programmable acoustic metastructure integrated at the probe front end, implemented based on the ultrasonic probe device described in the first aspect, comprising the following steps: The calibration step involves establishing a mapping relationship between control quantities and equivalent time delay, beam pointing, and focus position for each pixel cavity or partition of the programmable acoustic superstructure module, and generating a lookup table model or fitting model. In the state generation step, the target azimuth angle, target elevation angle and target focusing depth are input, and the control quantities of each pixel cavity used to realize the three-dimensional wavefront distribution of the target are calculated and generated based on the mapping relationship. The volume scanning sequence execution steps involve setting a volume scanning sequence composed of different combinations of azimuth angles, elevation angles, and focusing depths. Under the condition that the probe is stationary, the corresponding control quantities are applied sequentially, and the ultrasonic waves are transmitted and the echo data is received simultaneously. The three-dimensional reconstruction step involves performing compensated beamforming and spatial registration on the echo data based on the control states corresponding to each transmission and reception, and then performing voxel-level compositing to construct the three-dimensional volume data of the target area. The closed-loop optimization step involves calculating the quality index of the three-dimensional volume data. When the quality index is lower than a preset quality threshold, the control state of the next volume scan sequence is adjusted and updated based on the quality index, and the volume scan sequence execution steps are repeated.

[0013] In one possible implementation, the calibration step further includes: Repeated measurements were performed under different temperature conditions to establish temperature compensation parameters, as well as batch consistency correction parameters and interlayer collaborative compensation parameters; In the three-dimensional reconstruction step, the beamforming and spatial registration processes are compensated based on the temperature compensation parameters, batch consistency correction parameters, and interlayer collaborative compensation parameters.

[0014] In one possible implementation, when the pixel cavity array layer is a two-dimensional area array arrangement structure, the state generation step specifically includes: generating linear time delay gradients in the x and y directions of the two-dimensional area array according to the target azimuth angle and the target elevation angle, and mapping the two-dimensional time delay distribution to the control voltage of each pixel or partition to achieve dual-axis deflection state generation; When the pixel cavity array layer is a three-dimensional stacked structure, the state generation step specifically includes: generating collaborative control parameters for each layer according to the target three-dimensional focal position or the target volume scanning path, so that the multi-layer structure as a whole forms a predetermined spherical or ellipsoidal equivalent wavefront to achieve three-dimensional focusing or volume scanning state generation.

[0015] Compared with the prior art, the ultrasonic probe device with integrated programmable acoustic metastructure at the probe front end provided by the present invention has the following advantages: By placing a programmable acoustic metastructure module between the output end of the ultrasonic transducer module and the acoustic window, equivalent propagation delay or equivalent phase modulation with two-dimensional spatial distribution or three-dimensional stacked distribution can be provided under stationary probe conditions. This supports azimuth deflection, elevation deflection, three-dimensional focusing, and volume scanning state switching of the ultrasonic beam, reducing reliance on mechanical scanning mechanisms and improving system reliability and repeatability. The drive and control module generates control commands based on the target deflection angle and target focusing depth, changing the spatial delay or phase distribution formed by the programmable acoustic metastructure module. This achieves real-time programmable switching of wavefront modulation, overcoming the limitation of fixed acoustic lenses or metasurfaces that can only provide single wavefront modulation capabilities. The imaging and adaptive algorithm module performs compensated beamforming on the echo data based on the current state of the programmable acoustic metastructure module, and performs angle recombination, voxel-level recombination, and volume data reconstruction, effectively improving the stability of three-dimensional imaging, reducing speckle and sidelobe effects, and improving image quality. By using an imaging and adaptive algorithm module to update the control state of the programmable acoustic superstructure module in a closed loop when the quality index fails to reach a preset quality threshold, adaptive volume imaging is achieved, ensuring the consistency and stability of imaging quality. The entire device can achieve volume data acquisition and 3D reconstruction without relying on a high-channel 2D area array electronic scanning, obtaining 3D imaging effects with a lower channel number, effectively reducing system cost, power consumption, and packaging complexity. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1This invention provides a schematic diagram of the structure of an ultrasonic probe device with an integrated programmable acoustic metastructure at the probe front end. Figure 2 This is a cross-sectional structural diagram of the ultrasonic probe device provided by the present invention; Figure 3 An exploded view of the pixel cavity array layer; Figure 4 for Figure 3 Enlarged cross-sectional view of the pixel cavity array layer at section AA; Figure 5 for Figure 3 Top view of the electrode layout of the pixel cavity array layer shown; Figure 6 A schematic diagram of a three-dimensional stacked pixelated programmable acoustic superstructure is shown. Figure 7 A schematic diagram of a pixel cavity with adjustable time delay and sound beam deflection driven by an electric field-responsive medium is shown. Figure 8 A flowchart of an ultrasound imaging method with a programmable acoustic metastructure integrated at the probe front end, as provided in this application, is shown. Detailed Implementation

[0017] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0018] The accompanying drawings illustrate various structural schematics according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0019] In the context of this application, when a layer / element is referred to as being "above" another layer / element, the layer / element may be directly above the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "above" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0020] Figure 1 A schematic diagram of an ultrasonic probe device with an integrated programmable acoustic metastructure at the probe tip, as provided in this application, is shown. Figure 1As shown, the ultrasonic probe device provided in this embodiment of the invention includes an ultrasonic transducer module 100, a programmable acoustic superstructure module 200, a drive and control module 300, and an imaging and adaptive algorithm module 400.

[0021] The ultrasonic transducer module 100 is used to transmit and receive ultrasonic signals. The transducer in the ultrasonic transducer module 100 can be a single transducer, a one-dimensional linear array, a 1.5D array, a two-dimensional area array, a matrix array, or a sparse two-dimensional array.

[0022] The programmable acoustic superstructure module 200 is disposed between the output end of the ultrasonic transducer module 100 and the acoustic window, and is used to provide equivalent propagation delay or equivalent phase modulation for two-dimensional spatial distribution or three-dimensional stacked distribution to support azimuth deflection, pitch deflection, three-dimensional focusing and volume scanning state switching.

[0023] The drive and control module 300 is used to apply control signals to each pixel cavity of the programmable acoustic superstructure module 200, output voltage or equivalent actuation signal, and generate control commands according to the target deflection angle and target focusing depth to change the spatial time delay distribution or phase distribution formed by the programmable acoustic superstructure module 200.

[0024] The imaging and adaptive algorithm module 400 is used to perform compensated beamforming on the echo data based on the current state of the programmable acoustic superstructure module 200, and to perform angle compositing, voxel-level compositing, volume data reconstruction and quality evaluation. When the quality index does not reach the preset quality threshold, the control state of the programmable acoustic superstructure module 200 is updated in a closed loop. If necessary, the superstructure control state for the next transmission is updated in a closed loop.

[0025] Figure 2 This is a cross-sectional structural diagram of the ultrasonic probe device provided by the present invention; Figure 3 An exploded view of the pixel cavity array layer; Figure 3 The example uses a 2×4 pixel cavity array, with no limit on the number of rows and columns.

[0026] Figure 4 for Figure 3 The image shows an enlarged cross-sectional view of the pixel cavity array layer at section AA.

[0027] Figure 5 for Figure 3 The diagram shows a top view of the electrode layout of the pixel cavity array layer; where column partitioning control is used, with each column sharing a drive line.

[0028] See Figures 2 to 5The programmable acoustic superstructure module 200 is a pixelated variable sound velocity or variable time delay layer, which sequentially includes a base electrode layer 210, a pixel cavity array layer 220, and a top cover sealing layer 230 along the direction from the transducer to the object to be imaged. The pixel cavity array layer 220 is preferably disposed between the matching layer and the acoustic window, and is integrally sealed with the probe housing. The acoustic window is a sealable insulating film or a solid acoustic window, with a coupling medium or coupling pad on the outside.

[0029] Multiple electrode units are disposed on the substrate electrode layer 210 and connected to the drive and control module 300 via leads. An insulating layer 211 covers the electrode surface for electrical isolation, corrosion resistance, and reduction of leakage risk. The substrate material can be a flexible circuit substrate or a rigid substrate, selected based on the probe's shape and reliability requirements.

[0030] The pixel cavity array layer 220 forms a multi-row, multi-column array of pixel cavities 221. Isolation walls 222 are provided between the pixel cavities to suppress lateral crosstalk and improve pixel independence. Each pixel cavity is filled with an electric field-responsive medium 223. Under the action of an applied electric field, the electric field-responsive medium 223 changes its effective sound velocity or equivalent propagation constant, thereby changing the equivalent propagation time delay of the ultrasonic wave passing through the pixel cavity. The medium can be an electric field-responsive fluid, a field-responsive composite material, or an equivalent dielectric layer corresponding to an electrically controlled deformable structure. The selection of the medium should meet the upper limits of loss, temperature drift, and electrical safety requirements within the operating frequency band.

[0031] The top cover sealing layer 230 is sealed to the pixel cavity array layer 220 to form a closed cavity. The top cover sealing layer 230 can be integrated with the outer acoustic window or tightly fitted to the acoustic window to ensure acoustic continuity and pressure and moisture resistant encapsulation capabilities.

[0032] The pixel cavity array layer is equipped with a liquid injection port 240 to complete the medium injection and degassing process. After liquid injection, the port is sealed by heat sealing or adhesive sealing, and a secondary sealing layer is set to improve long-term sealing reliability. The degassing process includes vacuum degassing or circulating degassing to reduce the impact of air bubbles on acoustic transmission. Electrode leads are connected to the drive circuit via flexible interconnects. The sealing structure should meet the requirements for cleaning, disinfection, and long-term moisture resistance.

[0033] Each pixel cavity introduces an equivalent propagation time delay or equivalent phase delay to the passing ultrasonic waves. By changing the effective sound velocity or equivalent propagation parameters of the medium within the pixel cavity, the time delay of that pixel is altered, thus forming a spatial time delay distribution.

[0034] In one embodiment of the present invention, see Figure 5The pixelated variable sound velocity or variable time delay layer employs a two-dimensional planar array structure to simultaneously generate spatial time delay gradients in the azimuth and elevation directions, thereby achieving biaxial deflection control of the ultrasonic beam. For the two-dimensional planar array structure, controllable time delay gradients can be formed in the x and y directions respectively. An approximately linear time delay gradient is formed on the pixel array, causing the main energy of the beam to deflect towards the target direction. By forming gradients in the x and y directions respectively, biaxial deflection of the azimuth and elevation angles can be achieved. An approximately quadratic time delay distribution, spherical time delay distribution, or ellipsoidal time delay distribution is formed on the pixel array, causing the beam to focus at the target depth or the target's three-dimensional spatial position. By changing the curvature of the time delay distribution and the spatial center position, the depth of focus and focal coordinates can be changed. The number of rows and columns of the pixel array can be 2xN, 3xN, or NxM, and the pixel spacing and cavity size are determined according to the operating frequency band and the target time delay range.

[0035] In another embodiment of the invention, see Figure 6 The pixel cavity array layer 220 includes at least two stacked pixel cavities along the sound propagation direction. The electrode units corresponding to the pixel cavities in different layers can be controlled independently. The pixel cavities in each layer are controlled collaboratively, each undertaking coarse adjustment, fine adjustment, or compensation functions to expand the total time delay dynamic range, improve wavefront modulation resolution, and achieve three-dimensional focusing and volume scanning wavefront generation. Each layer can use the same or different pixel size, cavity height, and adjustment range to achieve a larger equivalent time delay dynamic range, higher degrees of freedom in three-dimensional wavefront modulation, or layered collaborative focusing.

[0036] Figure 6 This invention illustrates a three-dimensional stacked pixelated programmable acoustic superstructure according to an embodiment of the present invention. The superstructure consists of a 4×4 pixel cavity array in the xy-plane, with three layers stacked along the z-direction to form a three-dimensional controllable structure. Each pixel cavity layer can be independently controlled or partitioned to create an adjustable equivalent time delay or phase distribution in three-dimensional space, thereby achieving biaxial deflection, three-dimensional focusing, and volumetric scanning imaging of the ultrasonic beam.

[0037] In one embodiment, the pixel center-to-pixel distance between adjacent pixel cavities in the pixel cavity array layer 220 is less than half the wavelength of the ultrasonic wave in the coupling medium between the programmable acoustic superstructure module 200 and the object to be imaged. By controlling the pixel center-to-pixel distance to meet the subwavelength condition, the generation of grating lobes during wavefront modulation can be effectively suppressed, ensuring the spatial resolution and imaging quality of beam deflection and focusing.

[0038] The electrode structure of the electrode unit adopts any one of the following: top-and-bottom opposed electrodes, coplanar electrodes, row-and-column interleaved addressing electrodes, or multilayer interconnected electrode structures. Opposed electrodes are used to form an approximately vertical electric field, coplanar electrodes are used to form a lateral electric field or a local electric field distribution, row-and-column interleaved addressing structures are used to reduce the number of independent leads in a two-dimensional pixel array, and multilayer interconnected electrode structures are used for hierarchical control in three-dimensional stacked superstructures.

[0039] The drive and control module 300 controls the pixelated variable sound velocity or variable time delay layer using any one or more combinations of pixel-independent control, row and column control, two-dimensional block partitioning control, azimuth / pitch independent control, or layered collaborative control. Row and column control and block partitioning control can be used to reduce the number of drive channels; pixel-independent control can be used to obtain wavefront modulation with higher degrees of freedom; azimuth / pitch independent control can be used to realize dual-axis deflection; and multi-layered collaborative control can be used to realize three-dimensional focusing, layered compensation, and volume scanning wavefront generation.

[0040] The principle of electric field response medium driving is introduced below.

[0041] See Figure 7 Each sub-figure represents a local cross-sectional view of a pixel cavity, with the white upward arrow indicating the main propagation direction of ultrasound within a single pixel cavity. In this illustration, the propagation direction within a single pixel cavity remains constant. The function of the pixel cavity is not to directly refract the sound beam by changing the propagation path, but rather to alter the effective sound velocity or equivalent propagation constant of the electric field response medium 223 by applying an external electric field. This changes the equivalent propagation delay introduced by the pixel cavity, causing the wavefront at that pixel location to arrive at the superstructure exit surface earlier or later.

[0042] When multiple pixel cavities are subjected to different electric field intensities in the lateral direction, different equivalent time delays are generated at different positions, forming a spatial time delay gradient or spatial phase gradient on the exit surface. This spatial gradient determines the tilt direction and curvature of the overall wavefront, thus manifesting as a deflection of the main lobe direction of the sound beam on the array scale, or as a change in the focusing position. Figure 7 The upper curve represents how the overall shape of the emitted wavefront changes as the pixel delay distribution changes from state one to state three, resulting in different deflection angles or different scanning trajectories. Therefore, the propagation direction within a single pixel cavity remains unchanged, while the deflection is generated by the array-level delay gradient.

[0043] In another embodiment of the invention, the programmable acoustic superstructure module 200 is configured as a detachable probe cap module. The imaging and adaptive algorithm module 400 is also used to identify the type of the connected probe cap module and automatically select the imaging compensation parameters and calibration model corresponding to the type. Different modules can correspond to different deflection angle ranges or different focusing depth ranges, realizing discrete wavefront switching, which is suitable for early prototypes and rapid verification in multiple scenarios.

[0044] The working principle of the ultrasonic probe device provided by the present invention is as follows: For each pixel cavity, each partition, or each stacked unit in the pixel cavity array layer, establish the correspondence between control quantities and equivalent time delay, equivalent phase, beam pointing, and focal position to form a lookup table model, fitting model, or data-driven model. Calibration can be performed using a standard medium water tank, a standard phantom, or a three-dimensional sound field measurement system to measure transmission response, echo response, or spatial sound field distribution, and invert the corresponding parameters.

[0045] Input the target azimuth angle, target elevation angle, and target focus depth or target 3D focal coordinates, calculate the target 3D wavefront distribution and map it to control quantities of pixels, partitions or stacked structures.

[0046] Establish the spatial registration relationship between the probe coordinate system and the volume imaging coordinate system, and compensate for the phase error, amplitude error, pointing error, and focus deviation obtained from calibration. If necessary, establish a temperature compensation table, batch consistency correction parameters, and inter-layer collaborative compensation parameters, and write the calibration parameters into the probe storage or system configuration file.

[0047] Taking a 4x4x3 three-dimensional stacked pixel array as an example, voltage scanning is applied to each partition of each layer. The sound field distribution under different control states is obtained using a hydrophone array or three-dimensional scanning measurement method. The lookup table relationship between the control quantity and the equivalent time delay, main lobe direction, and focal position is then obtained through inversion. During imaging, the control voltage for each layer is obtained by looking up the table according to the target's three-dimensional wavefront distribution and then applied.

[0048] This application also provides an ultrasound imaging method with a programmable acoustic metastructure integrated at the probe tip, implemented based on the ultrasound probe device described in the above embodiments. Figure 8 As shown, the method includes the following steps: S101, Calibration Steps. For each pixel cavity or partition of the programmable acoustic superstructure module 200, establish the mapping relationship between the control quantity and the equivalent time delay, beam pointing and focus position, and generate a lookup table model or fitting model.

[0049] Preferably, temperature compensation parameters are established by repeatedly measuring under different temperature conditions, as well as batch consistency correction parameters and interlayer collaborative compensation parameters.

[0050] S102, State Generation Step. Input the target azimuth angle, target elevation angle, and target focus depth. Calculate and generate the control quantities for each pixel cavity to achieve the target's three-dimensional wavefront distribution based on the mapping relationship.

[0051] When the pixel cavity array layer 220 is a two-dimensional area array arrangement structure, the state generation step S102 specifically includes: generating linear time delay gradients in the x and y directions of the two-dimensional area array according to the target azimuth angle and target elevation angle, and mapping the two-dimensional time delay distribution to the control voltage of each pixel or partition to realize the dual-axis deflection state generation.

[0052] When the pixel cavity array layer 220 is a three-dimensional stacked structure, the state generation step S102 specifically includes: generating collaborative control parameters for each layer according to the target three-dimensional focal position or the target volume scanning path, so that the multi-layer structure forms a predetermined spherical or ellipsoidal equivalent wavefront as a whole, so as to realize the generation of three-dimensional focusing or volume scanning state.

[0053] S103, Volume Scan Sequence Execution Steps. A volume scan sequence composed of different combinations of azimuth angles, elevation angles, and focusing depths is set. With the probe stationary, the corresponding control quantities are applied sequentially, and ultrasonic wave transmission and echo data reception are performed simultaneously.

[0054] S104, 3D Reconstruction Steps. Based on the control states corresponding to each transmission and reception, compensated beamforming and spatial registration are performed on the echo data, followed by voxel-level compositing to construct 3D volumetric data of the target area. During reconstruction, beamforming and spatial registration are compensated based on temperature compensation parameters, batch consistency correction parameters, and interlayer collaborative compensation parameters. Multi-plane reconstruction of cross-sections, longitudinal sections, coronal planes, or arbitrary oblique sections can be performed on the 3D volumetric data, followed by 3D visualization.

[0055] S105, Closed-loop optimization step. Calculate the quality indicators of the 3D volume data, including focus index, sidelobe index, sharpness index, consistency index, or voxel quality index. When the quality indicators are lower than the preset quality threshold, adjust and update the control state of the next round of volume scan sequence based on the quality indicators, and repeat step S103 of the volume scan sequence to achieve closed-loop optimization.

[0056] Example 1: 2x4 pixel (pixel cavity) deflection Two-by-four pixels are arranged in a column-wise increasing time delay distribution. The first to fourth columns correspond to time delays Δt1, Δt2, Δt3, and Δt4, respectively, with Δt1 being less than Δt4. The target time delay of each column is mapped to voltages V1 to V4 according to a calibration lookup table. The same voltage is applied to the pixel cavities in the same column, thus creating a linear time delay gradient at the exit surface to achieve deflection. The deflection angle is determined by the magnitude of the gradient.

[0057] Example 2: 2x4 pixel focusing Two-by-four pixels are arranged horizontally to form an approximate quadratic time delay distribution, with the central column corresponding to a larger time delay and the side columns corresponding to smaller or opposite times. The target time delay in each column is mapped to a voltage and applied, causing the exit surface to form a quadratic time delay distribution, thus achieving focusing at a depth of focus zF. Changing the curvature of the distribution alters the depth of focus.

[0058] Example 3: 4x4 pixel 2D area array with dual-axis deflection A 4x4 pixel array simultaneously generates time delay gradients in both the x and y directions. The system generates a two-dimensional target time delay distribution based on the target azimuth and elevation angles, and maps the target time delay of each pixel cavity or partition to the corresponding control voltage through calibration lookup. The combined time delay gradients of different pixels in the x and y directions jointly determine the emission direction of the main lobe in three-dimensional space, thereby achieving dual-axis deflection scanning.

[0059] Example 4: 4x4x3 3D ​​stacked superstructure focusing and volume scanning A three-layered, four-by-four pixel array is sequentially arranged along the z-axis, with each layer receiving a control input to form a layered time-delay modulation. The system generates collaborative control parameters for each layer based on the target's 3D focal position or the target's scanning path, enabling the three-layer structure to form a predetermined spherical or ellipsoidal equivalent wavefront. By changing the target azimuth, elevation, and depth of focus, successive scanning and 3D reconstruction of different voxel regions can be achieved even when the probe is stationary.

[0060] The temperature compensation calibration method is as follows: Different control values ​​are applied to each partition or pixel in a standard medium to acquire transmission or echo data; equivalent time delay is inverted and lookup table parameters are generated; temperature compensation parameters are established by repeated measurements under different temperature conditions; calibration parameters are written to probe storage or system configuration files and called up in imaging.

[0061] It is worth mentioning that movable baffles or movable channel components can be set inside the pixel cavity to form different effective propagation path lengths at different positions, thereby providing discrete time delay levels. The movable components are driven by micro-actuators, and the actuation methods can be electrostatic actuation, piezoelectric actuation, or micro-valve-controlled fluid switching. Preferably, a few-level time delay quantization is used to reduce control complexity and improve consistency.

[0062] The control method can be pixel-level, zone-level, row-column-level, hierarchical, or hybrid control; the superstructure can be a single-layer structure, a double-layer structure, or a multi-layer superimposed structure; the medium can be an electric field-responsive fluid, a composite material, or an equivalent medium layer of an electrically controlled deformable structure; the scanning sequence can be selected according to application requirements, including two-dimensional planar coverage, three-dimensional volume coverage, or high-resolution three-dimensional scanning of local areas; in three-dimensional mode, voxel-level reconstruction, local fine focusing, or dynamic updates can be performed on the selected region of interest.

[0063] The ultrasonic probe device with an integrated programmable acoustic metastructure at the probe front end provided in this application has the following advantages: 1. Achieve dual-axis deflection of the ultrasonic beam in both azimuth and pitch directions and three-dimensional spatial focusing under the condition that the probe is stationary, reducing the dependence on mechanical scanning mechanisms; 2. Supports volume scanning acquisition, volume data reconstruction, multi-plane reconstruction, and 3D visualization, enhancing the spatial information representation capability of the target area; 3. By using angle compounding, voxel-level compounding, and adaptive closed-loop control, the stability of 3D imaging is improved and the effects of speckle and sidelobe are reduced. 4. Achieve 3D imaging effects close to those of a 2D area array with a lower number of channels, reducing system cost, power consumption, and packaging complexity; 5. The modular integration of the probe front end facilitates packaging, maintenance, and upgrades, and can be expanded to operate in two-dimensional / three-dimensional, multi-frequency band, and multi-mode modes; 6. Improve cross-device consistency and long-term stability through calibration, spatial registration and compensation mechanisms.

[0064] To achieve the same structure, those skilled in the art can also devise methods that are not entirely identical to those described above. Furthermore, although various embodiments have been described separately above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0065] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0066] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. The scope of this application is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this application, and all such substitutions and modifications should fall within the scope of this application.

Claims

1. An ultrasonic probe device with a programmable acoustic metastructure integrated at the probe tip, characterized in that, include: An ultrasonic transducer module is used to transmit and receive ultrasonic signals; A programmable acoustic superstructure module is disposed between the output end of the ultrasonic transducer module and the acoustic window. It is used to provide equivalent propagation delay or equivalent phase modulation for two-dimensional spatial distribution or three-dimensional stacked distribution to support the switching of azimuth deflection, pitch deflection, three-dimensional focusing and volume scanning states of the ultrasonic beam. The driving and control module is used to apply control signals to each pixel cavity of the programmable acoustic superstructure module and generate control commands according to the target deflection angle and target focusing depth to change the spatial time delay distribution or phase distribution formed by the programmable acoustic superstructure module. The imaging and adaptive algorithm module is used to perform compensated beamforming on the echo data based on the current state of the programmable acoustic superstructure module, and to perform angle compositing, voxel-level compositing, volume data reconstruction and quality evaluation. When the quality index does not reach the preset quality threshold, the control state of the programmable acoustic superstructure module is updated in a closed loop.

2. The ultrasonic probe device according to claim 1, characterized in that, The programmable acoustic superstructure module is a pixelated variable sound velocity or variable time delay layer, which includes, in sequence, a substrate electrode layer, a pixel cavity array layer and a top cover sealing layer along the direction from the transducer to the object to be imaged. The base electrode layer is provided with multiple electrode units, which are connected to the drive and control module through leads; The pixel cavity array layer forms multiple rows and columns of pixel cavities. Each pixel cavity is filled with an electric field responsive medium. Under the action of an applied electric field, the electric field responsive medium changes its effective sound velocity or equivalent propagation constant, thereby changing the equivalent propagation time delay of the ultrasonic wave passing through the pixel cavity. Isolation walls for suppressing lateral crosstalk are provided between the pixel cavities. The upper cover sealing layer is sealed to the pixel cavity array layer to form a closed cavity.

3. The ultrasonic probe device according to claim 2, characterized in that, The pixelated variable sound velocity or variable time delay layer adopts a two-dimensional array arrangement structure to simultaneously form spatial time delay gradients in the azimuth and pitch directions, so as to realize biaxial deflection control of the ultrasonic beam.

4. The ultrasonic probe device according to claim 2, characterized in that, The pixel cavity array layer includes at least two stacked pixel cavities along the sound propagation direction, and the electrode units corresponding to the pixel cavities of different layers can be controlled independently.

5. The ultrasonic probe device according to claim 2, characterized in that, In the pixel cavity array layer, the pixel center distance between adjacent pixel cavities is less than half the ultrasonic wavelength in the coupling medium between the programmable acoustic superstructure module and the object to be imaged.

6. The ultrasonic probe device according to claim 2, characterized in that, The electrode structure of the electrode unit adopts any one of the following: top-bottom opposed electrodes, coplanar electrodes, row-column interleaved addressing electrodes, or multilayer interconnected electrode structure. The driving and control module controls the pixelated variable sound speed or variable time delay layer by any one or more combinations of pixel-independent control, row and column control, two-dimensional block partition control, azimuth / pitch independent control, or hierarchical collaborative control.

7. The ultrasonic probe device according to claim 1, characterized in that, The programmable acoustic superstructure module is configured as a detachable probe cap module. The imaging and adaptive algorithm module is also used to identify the type of the connected probe cap module and automatically select the imaging compensation parameters and calibration model corresponding to the type.

8. An ultrasonic imaging method integrating a programmable acoustic metastructure at the probe tip, implemented based on the ultrasonic probe device according to any one of claims 1 to 7, characterized in that, Includes the following steps: The calibration step involves establishing a mapping relationship between control quantities and equivalent time delay, beam pointing, and focus position for each pixel cavity or partition of the programmable acoustic superstructure module, and generating a lookup table model or fitting model. In the state generation step, the target azimuth angle, target elevation angle and target focusing depth are input, and the control quantities of each pixel cavity used to realize the three-dimensional wavefront distribution of the target are calculated and generated based on the mapping relationship. The volume scanning sequence execution steps involve setting a volume scanning sequence composed of different combinations of azimuth angles, elevation angles, and focusing depths. Under the condition that the probe is stationary, the corresponding control quantities are applied sequentially, and the ultrasonic waves are transmitted and the echo data is received simultaneously. The three-dimensional reconstruction step involves performing compensated beamforming and spatial registration on the echo data based on the control states corresponding to each transmission and reception, and then performing voxel-level compositing to construct the three-dimensional volume data of the target area. The closed-loop optimization step involves calculating the quality index of the three-dimensional volume data. When the quality index is lower than a preset quality threshold, the control state of the next volume scan sequence is adjusted and updated based on the quality index, and the volume scan sequence execution steps are repeated.

9. The ultrasound imaging method according to claim 8, characterized in that, The calibration steps also include: Repeated measurements were performed under different temperature conditions to establish temperature compensation parameters, as well as batch consistency correction parameters and interlayer collaborative compensation parameters; In the three-dimensional reconstruction step, the beamforming and spatial registration processes are compensated based on the temperature compensation parameters, batch consistency correction parameters, and interlayer collaborative compensation parameters.

10. The ultrasound imaging method according to claim 8, characterized in that, When the pixel cavity array layer is a two-dimensional area array arrangement structure, the state generation step specifically includes: generating linear time delay gradients in the x and y directions of the two-dimensional area array according to the target azimuth angle and target elevation angle, and mapping the two-dimensional time delay distribution to the control voltage of each pixel or partition to realize the dual-axis deflection state generation; When the pixel cavity array layer is a three-dimensional stacked structure, the state generation step specifically includes: generating collaborative control parameters for each layer according to the target three-dimensional focal position or the target volume scanning path, so that the multi-layer structure as a whole forms a predetermined spherical or ellipsoidal equivalent wavefront to achieve three-dimensional focusing or volume scanning state generation.

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