Scanning system for the acoustic field of ultrasonic transducers

Abstract

This disclosure provides a scanning system for the acoustic field of an ultrasound transducer. The scanning system includes: a computer system, an oscilloscope, a water treatment subsystem, and a scanning mechanism; the scanning mechanism includes: a frame, a water tank, a hydrophone positioning and moving mechanism, a transducer positioning and moving mechanism, and a hydrophone; the transducer positioning and moving mechanism is mounted on the frame; the oscilloscope is connected to the hydrophone; this solution, through a multi-subsystem collaborative architecture (closed-loop water treatment, integrated scanning mechanism on a common substrate, and real-time computer control linkage), achieves the elimination of signal distortion caused by cavitation interference and the acquisition of the true sound pressure distribution in the acoustic field scanning of clinical-grade high-intensity (high sound pressure) focused ultrasound transducers; supports complete acoustic field scanning without blind spots for the largest size therapeutic transducers; and significantly reduces the single-test time to meet the needs of production line batch verification.

Description

Technical Field

[0001] This utility model relates, and particularly relates, to a scanning system for the sound field of an ultrasonic transducer. Background Technology

[0002] As a core component of HIFU (High-Intensity Focused Ultrasound) therapy equipment, the transducer's acoustic field characteristics directly determine the safety and effectiveness of treatment. Therefore, it is necessary for the industry to scan the acoustic field characteristics of transducers to understand their properties. However, existing acoustic field scanning systems have systemic defects: when the sound pressure of the measured sound field exceeds 15 MPa, the cavitation effect of water causes severe distortion of the acoustic field data, making it impossible for current technologies to obtain the true sound field distribution under high sound pressure. Furthermore, hydrophones have a high failure rate in high sound pressure environments, leading to a surge in equipment maintenance costs. In addition, large-size transducers have scanning blind spots, resulting in missing acoustic field data (edge ​​focus cannot be captured); this limits the sound pressure supported by existing scanning systems, forcing manufacturers to use highly risky extrapolation algorithms, indirectly increasing the rate of clinical treatment accidents. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defects of the existing sound field scanning system, which causes severe distortion of the sound pressure signal due to cavitation effect under high sound pressure and causes high-frequency damage to the hydrophone. The present invention provides a scanning system, method and electronic equipment for the sound field of ultrasonic transducers.

[0004] This disclosure solves the above-mentioned technical problems through the following technical solution:

[0005] This disclosure provides a scanning system for the sound field of an ultrasonic transducer, the scanning system comprising: a computer system, an oscilloscope, a water treatment subsystem, and a scanning mechanism;

[0006] The scanning mechanism includes: a frame, a water tank, a hydrophone positioning and moving mechanism, a transducer positioning and moving mechanism, and a hydrophone;

[0007] The frame serves as the overall load-bearing structure;

[0008] The water tank is used to hold the water medium provided by the water treatment subsystem;

[0009] The hydrophone positioning and moving mechanism is mounted on the frame and is used to support the hydrophone and drive the hydrophone to perform three-dimensional motion.

[0010] The transducer positioning and moving mechanism is installed on the frame and is used to support the ultrasonic transducer to be tested and adjust the spatial orientation of the ultrasonic transducer to be tested.

[0011] The oscilloscope is connected to the hydrophone, which is used to convert the acquired sound pressure signal into an electrical signal; the oscilloscope is used to receive the electrical signal, process the electrical signal, and transmit it to the computer system.

[0012] The computer system is connected to the hydrophone positioning and moving mechanism of the scanning mechanism via a motion control interface, and to the oscilloscope via a data acquisition interface, and is used to perform scanning control and sound field modeling.

[0013] The water treatment subsystem consists of a water filtration unit and a vacuum degassing unit connected in series. The water treatment subsystem is used to provide water medium that meets preset standards to the water tank.

[0014] Optionally, the water filtration unit is used to remove suspended solids and ions with a particle size greater than or equal to 0.0001 micrometers from the water;

[0015] The vacuum degassing unit is used to reduce the oxygen content of the water medium to below 2 mg / L.

[0016] Optionally, the inner surface of the water tank is covered with sound-absorbing material.

[0017] Optionally, the hydrophone includes any of the following:

[0018] High-pressure resistant fiber optic hydrophone for measuring high-intensity (high sound pressure) focused ultrasonic transducers with sound pressure greater than or equal to the sound pressure threshold;

[0019] High-sensitivity thin-film hydrophone for far-field scanning of non-focusing transducers;

[0020] Ceramic hydrophones are used for measurements of focused ultrasonic transducers where the measurement accuracy error requirement is greater than or equal to an error threshold, and / or the sensitivity requirement is greater than or equal to a sensitivity threshold.

[0021] Optionally, the transducer positioning and moving mechanism includes a base plate, a fixing plate, and a support beam;

[0022] The substrate and the frame are fixed by a sliding rod;

[0023] The fixing plate is connected to the base plate in an adjustable rigid connection through four sets of adjustable fixing components, the adjustable fixing components including screws and wing nuts;

[0024] The support beam is linked to the fixed plate through two guide shafts, and a bubble level is installed on the support beam;

[0025] The support beam is used to fix the ultrasonic transducer under test and drive the ultrasonic transducer under test to move up and down along the Z-axis.

[0026] Optionally, the support beam is used to position the ultrasonic transducer to be tested directly above or below the hydrophone.

[0027] Optionally, the screw of the adjustable fixing component penetrates vertically through the base plate and the fixing plate; the wing nut includes: a first wing nut screwed on the upper surface of the fixing plate and a second wing nut screwed on the lower surface of the fixing plate; the adjustable fixing component is used to adjust the horizontal tilt angle of the support beam.

[0028] Optionally, the hydrophone positioning and moving mechanism includes a first automatic adjustment unit; the first automatic adjustment unit includes a first servo motor for driving a first ball screw to move the hydrophone positioning and moving mechanism horizontally.

[0029] The transducer positioning and moving mechanism includes a second automatic adjustment unit; the second automatic adjustment unit includes a second servo motor, which drives a second ball screw to move the transducer positioning and moving mechanism.

[0030] This disclosure also provides a scanning method for the acoustic field of an ultrasonic transducer, characterized in that the scanning method is implemented based on the scanning system for the acoustic field of an ultrasonic transducer described in any of the preceding claims, and the scanning method includes:

[0031] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this disclosure.

[0032] The positive advancements of this disclosure are as follows: This solution, through a multi-subsystem collaborative architecture (closed-loop water treatment, integrated scanning mechanism on a common substrate, and real-time computer control linkage), achieves the elimination of signal distortion caused by cavitation interference and the acquisition of the true sound pressure distribution in clinical-grade high-intensity (high sound pressure) focused ultrasound transducer sound field scanning; supports complete sound field scanning without blind spots for the largest size treatment transducers; and significantly reduces the single-test duration to meet the batch verification requirements of production lines. Attached Figure Description

[0033] Figure 1 A schematic diagram of a scanning system for the acoustic field of an ultrasonic transducer provided as an exemplary embodiment of this disclosure;

[0034] Figure 2 A schematic diagram of the structure of a scanning mechanism for a scanning system targeting the acoustic field of an ultrasonic transducer, provided as an exemplary embodiment of this disclosure;

[0035] Figure 3 A schematic diagram of the structure of a hydrophone positioning and moving mechanism for a scanning system for the sound field of an ultrasonic transducer, provided as an exemplary embodiment of this disclosure.

[0036] Figure 4A schematic diagram of the structure of a transducer positioning and moving mechanism for a scanning system for the acoustic field of an ultrasonic transducer, provided as an exemplary embodiment of this disclosure.

[0037] Figure 5 This is a partially enlarged schematic diagram of the scanning mechanism of a scanning system for an ultrasonic transducer sound field, provided as an exemplary embodiment of this disclosure. Detailed Implementation

[0038] The present disclosure is further illustrated below by way of embodiments, but the present disclosure is not limited to the scope of the embodiments described herein.

[0039] The prefixes such as "first" and "second" used in this disclosure are merely for distinguishing different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes used to distinguish descriptive objects in this disclosure does not constitute a limitation on the described objects. The description of the described objects is given in the context of the embodiments, and the use of such prefixes should not constitute unnecessary restrictions. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0040] In this embodiment of the disclosure, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information comply with relevant laws and regulations and do not violate public order and good morals.

[0041] Example 1

[0042] Corresponding to the foregoing embodiments of scanning systems for ultrasonic transducer sound fields, this disclosure also provides embodiments of scanning methods for ultrasonic transducer sound fields. In one specific embodiment, see [link to embodiment]. Figures 1 to 5The system comprises: a computer system 1, an oscilloscope 5, a water treatment subsystem, and a scanning mechanism 4. The scanning mechanism 4 includes: a frame 6, a water tank 9, a hydrophone positioning and moving mechanism 7, a transducer positioning and moving mechanism 8, and a hydrophone 12. The frame 6 serves as the overall load-bearing structure; the water tank 9 holds the water medium provided by the water treatment subsystem; the hydrophone positioning and moving mechanism 7, mounted on the frame 6, supports the hydrophone 12 and drives it to perform three-dimensional motion; the transducer positioning and moving mechanism 8, mounted on the frame 6, supports the ultrasonic transducer 21 under test and adjusts its spatial orientation; the oscilloscope 5 is connected to the hydrophone 12, which converts the acquired sound pressure signal into an electrical signal, and the oscilloscope 5 receives the electrical signal, processes it, and transmits it to the computer system 1; the computer system 1 is connected to the hydrophone positioning and moving mechanism 7 of the scanning mechanism 4 via a motion control interface, connected to the oscilloscope 5 via a data acquisition interface, and is used to perform scanning control and sound field modeling; the water treatment subsystem consists of a water filtration unit 2 and a vacuum degassing unit 3 connected in series, and provides the water tank 9 with a water medium that meets preset standards.

[0043] The ultrasound transducer acoustic field scanning system provided in this embodiment aims to measure the acoustic field distribution characteristics (such as sound pressure distribution, acoustic focal point location, -6dB focal area, etc.) of high-intensity focused ultrasound (HIFU) therapeutic transducers or non-focused ultrasound transducers in operation with high precision and safety. This system is particularly suitable for measuring large-sized (e.g., diameter up to 250mm) transducers with high sound pressure (e.g., sound pressure greater than 25MPa, sound intensity greater than 10000W / cm²). 2 The scanning system addresses several challenges in transducer acoustic field measurement, including interference from cavitation effects in water media, scanning blind zones, cumbersome operation, and low data accuracy. The scanning system comprises the following core functional subsystems, which work collaboratively to achieve the aforementioned objectives:

[0044] Computer System 1 serves as the system's control core and data processing center. Computer System 1 connects to the hydrophone positioning and moving mechanism 7 of the scanning mechanism 4 via its motion control interface (e.g., standard industrial interfaces such as USB and EtherCAT) to send precise motion commands (including target position, moving speed or step distance, and moving direction) to drive the mechanism in three-dimensional motion. Simultaneously, Computer System 1 connects to the oscilloscope 5 via its data acquisition interface (e.g., GPIB, USB, LAN) to receive and read the digitized sound pressure signals transmitted by the oscilloscope 5 in real time. Computer System 1 incorporates self-developed sound field scanning software, which is responsible for the automated scanning control of the entire measurement process (including generating the scanning path, coordinating motion and acquisition synchronization), and performing sound field modeling and analysis on the acquired data. Specifically, the software synchronously records the real-time spatial coordinates (X, Y, Z) of the hydrophone 12 and its corresponding sound pressure measurement value (P). It uses specific algorithms (such as interpolation, meshing, normalization, etc.) to construct a three-dimensional sound pressure distribution model of the transducer under test, and performs visualization (generating dot matrix diagrams, plane contour maps, three-dimensional sound field cloud maps, etc.) and calculation of key acoustic parameters (such as sound focus coordinates (X0, Y0, Z0), -6dB focal zone boundary and area, focal zone size, sound pressure peak value, side lobe information, etc.).

[0045] Oscilloscope 5: Serves as a device for acquiring and converting sound pressure signals. Oscilloscope 5 is directly connected to the electrical signal output of hydrophone 12. Its core function is to amplify, digitize (analog-to-digital conversion), and display / record the weak analog electrical signal (usually a voltage signal) detected by hydrophone 12, which reflects changes in sound pressure in the water. Oscilloscope 5 accurately measures the amplitude (corresponding to sound pressure level), waveform, and frequency of the sound pressure signal, and transmits the digitized sound pressure signal to computer system 1 in real time for further processing via its data output interface.

[0046] The water treatment subsystem provides a stable, high-purity water environment with low dissolved gas content for acoustic measurements. It is crucial for suppressing cavitation effects and ensuring the accuracy and safety of high sound pressure field measurements. This subsystem consists of two functional units connected in series:

[0047] Water filtration unit 2: This unit performs deep purification of tap water or initial water source. Its core function is to remove all solid suspended particles, colloidal substances, and dissolved ions from the water that may interfere with acoustic measurements. The treated water quality must meet the standard of a filtration accuracy of 0.0001 micrometers (0.1 nanometers). This high-purity water can significantly reduce the scattering effect of sound waves during propagation, avoid sound field distribution distortion caused by impurities, and reduce electrochemical interference to the hydrophone's electrical signal.

[0048] Vacuum Degassing Unit 3: This unit performs vacuum degassing on the water after deep purification by Water Filtration Unit 2. Its core function is to significantly reduce the content of dissolved gases in the water, especially oxygen and nitrogen. The treated water must meet the standard of dissolved oxygen content being reduced to below 2 mg / L (far lower than the approximately 8-10 mg / L of conventional tap water). Dissolved gases are the main source of cavitation nuclei in water. Deep degassing treatment can significantly improve the acoustic cavitation threshold of the water medium, effectively suppressing the violent collapse of cavitation bubbles under high sound pressure (e.g., >25 MPa), avoiding the risk of severe sound field distortion, noise interference, focus drift, and damage to hydrophone probes.

[0049] The ultimate goal of the water treatment subsystem is to continuously supply water tank 9 with water that simultaneously meets the preset standards of ultra-high filtration accuracy (0.0001 microns) and ultra-low oxygen content (<2 mg / L).

[0050] Scanning mechanism 4: The mechanical platform, motion execution unit, and measurement environment container that constitute the system. See details. Figure 2 Specifically, it includes:

[0051] Frame 6: Serves as the basic load-bearing structure and rigid support platform for the entire scanning mechanism 4. All other components are directly or indirectly mounted or fixed to frame 6, providing structural stability for the entire system and reducing the impact of vibration during operation on high-precision acoustic measurements.

[0052] Water tank 9: Fixed to the frame 6, it holds water medium provided by the water treatment subsystem that meets the aforementioned stringent standards. The ultrasonic transducer 21 and hydrophone 12 under test must be completely immersed in the water medium in the water tank 9 during the measurement process. The water medium is the carrier of ultrasonic waves and is also the necessary environment for sound field measurement.

[0053] Hydrophone positioning and moving mechanism 7: See details Figure 3 It is mounted on the frame 6. Its core function is to support the hydrophone 12 and drive it to perform precise and controllable motion scanning in three-dimensional space (X direction, Y direction, Z direction). This mechanism typically includes precision mechanical transmission components (such as ball screws and linear guides), drive components (such as servo motors), and a control system. It receives and executes motion commands from the computer system 1, enabling the hydrophone 12 to systematically scan the target area in the transducer sound field according to a preset mode (such as step mode or continuous mode) and path.

[0054] Transducer positioning and moving mechanism 8: See details Figure 4It is mounted on the frame 6. Its core function is to support the ultrasonic transducer 21 to be tested and precisely adjust its position and orientation in space. Position adjustment mainly refers to driving the transducer 21 to make a wide range of lifting and lowering movements in the Z-axis direction (usually the vertical direction) so as to immerse transducers of different sizes into the water medium in the water tank 9 at the appropriate depth and facilitate their installation and disassembly. Orientation adjustment mainly refers to precisely adjusting the levelness (i.e., the tilt angle around the X and Y axes) of the radiating end face (acoustic emission surface) of the transducer 21 through a precision leveling mechanism. This adjustment is crucial to ensuring that the transducer's acoustic beam axis and the pointing of the hydrophone 12 probe maintain a strict perpendicular / parallel relationship, which can effectively avoid measurement errors caused by angular deviations. This mechanism usually includes a lifting actuator (such as a trapezoidal lead screw, guide shaft, handwheel) and an angle leveling mechanism (such as a screw-wing nut adjustment assembly distributed at the four corners in conjunction with a level).

[0055] Hydrophone 12: This is the core sensor element for sound field measurement, fixedly mounted on the hydrophone positioning and moving mechanism 7 (e.g., via an I-shaped bracket 11). Its miniature probe is immersed in the water medium of the water tank 9, and its function is to convert the sound pressure fluctuations in the water acting on its probe into a proportionally weak electrical signal (voltage) output. The system can be adapted to different types of hydrophones to meet the needs of different measurement scenarios (e.g., high-voltage fiber optic hydrophones for high-intensity (high sound pressure) focused ultrasonic transducer measurements, high-sensitivity thin-film hydrophones for far-field scanning of non-focused transducers, and ceramic hydrophones for measurements of focused ultrasonic transducers where the measurement accuracy error requirement is greater than or equal to the error threshold and / or the sensitivity requirement is greater than or equal to the sensitivity threshold).

[0056] A brief description of the system's collaborative working principle:

[0057] 1. The water treatment subsystem prepares water media that meets preset standards (0.0001 micron filtration accuracy, <2 mg / L oxygen content) and injects / circulates it into the water tank 9.

[0058] 2. The ultrasonic transducer 21 under test is mounted and fixed on the bracket of the transducer positioning and moving mechanism 8. The immersion depth (Z-axis position) of the transducer 21 is adjusted by the mechanism and the leveling mechanism is used to ensure that its radiating end face is in a precise horizontal state (spatial pose).

[0059] 3. The hydrophone 12 is mounted and fixed on the hydrophone positioning and moving mechanism 7. The hydrophone 12 can be manually pre-positioned to the area near the estimated transducer acoustic focus.

[0060] 4. The computer system 1 sends instructions to the hydrophone positioning and moving mechanism 7 through its motion control interface according to the measurement parameters (scanning mode, range, speed / step distance) set by the user, driving the hydrophone 12 to move and scan in three-dimensional space along a predetermined path.

[0061] 5. During the scanning process, the hydrophone 12 detects the sound pressure signal in the water at its location in real time and converts it into an electrical signal output.

[0062] 6. This electrical signal is transmitted to oscilloscope 5.

[0063] 7. After amplifying and digitizing the analog electrical signal, the oscilloscope 5 transmits it to the computer system 1 in real time through its data output interface.

[0064] 8. The self-developed sound field scanning software of computer system 1 synchronously records the precise spatial coordinates (X, Y, Z) of hydrophone 12 and the corresponding sound pressure measurement value (P) transmitted by oscilloscope 5 at each moment.

[0065] 9. After the scan is completed or during real-time processing, the computer software uses the recorded (X, Y, Z, P) dataset to execute the sound field modeling algorithm, construct a three-dimensional sound pressure distribution model, visualize it, and calculate and output the required sound field characteristic parameters.

[0066] Optionally, in one specific embodiment, the water filtration unit 2 is used to remove suspended solids and ions with a particle size greater than or equal to 0.0001 micrometers from the water; the vacuum degassing unit 3 is used to reduce the oxygen content of the water medium to below 2 mg / L.

[0067] In this embodiment, the water treatment subsystem consists of a water filtration unit 2 and a vacuum degassing unit 3 connected in series. Its core function is to provide the water tank 9 with an ultrasonically conductive water medium that meets strict preset standards. This subsystem significantly improves the purity and stability of the water medium through a dual-deep treatment process, fundamentally solving the problems of cavitation interference and sound field distortion in high-intensity (high sound pressure) focused ultrasonic transducer measurements. Optionally, the specific parameter standards and technical basis are explained below:

[0068] 1. Core parameters and functions of water filtration unit 2

[0069] Functional objective: To eliminate the triple negative impact of impurities in water on acoustic measurements:

[0070] 1.1 Sound scattering effect: Suspended particulate matter (such as bacteria and colloids) and ions in water can cause the sound wave propagation path to deviate and distort the true distribution of the sound field (e.g., focus blurring, side lobe distortion).

[0071] 1.2 Electrochemical interference: Dissolved ions increase the conductivity of the water medium, interfering with the accuracy and signal-to-noise ratio of the electrical signal of hydrophone 12;

[0072] 1.3 Cavitation nucleus carrier: The gas adsorbed on the surface of the particles becomes the cavitation initiation point, reducing the acoustic cavitation threshold of the water medium.

[0073] Key technical parameters:

[0074] Filtration accuracy ≥ 0.0001 microns (0.1 nanometers).

[0075] Technical implications: This precision requirement means that the filter unit must be able to effectively remove all impurities in the water with a size greater than or equal to 0.0001 micrometers, including:

[0076] Microorganisms (bacteria typically 0.2-5 micrometers in size, viruses 0.02-0.3 micrometers in size);

[0077] Colloidal particles (typical size 0.001-1 micrometer);

[0078] Soluble ions (such as Na) + Approximately 0.2 nanometers in diameter, Cl - (Approximately 0.3 nanometers).

[0079] Implementation method: Achieved through a multi-stage series filtration process. A typical process includes: pre-microfiltration (removing large particles) → reverse osmosis membrane (desalination rate >99%) → ultrapure water polishing resin (deep deionization). The final output water quality meets the ultrapure water standard, with a resistivity >18MΩ·cm, which is far higher than that of conventional deionized water.

[0080] Technical effects:

[0081] The acoustic transmittance of the water medium was increased to >99.5% (compared to untreated tap water);

[0082] The signal-to-noise ratio (SNR) of the hydrophone 12 output signal is improved by ≥20 dB, ensuring the accuracy of sound pressure data acquisition.

[0083] 2. Core parameters and functions of vacuum degassing unit 3

[0084] Functional objective: To suppress acoustic cavitation induced by high sound pressure ultrasound (e.g., sound pressure > 25 MPa) in water media and avoid its serious consequences.

[0085] 2.1 Severe sound field distortion: The violent collapse of cavitation bubbles generates high-frequency noise, which drowns out the real sound pressure signal and causes focus drift;

[0086] 2.2 Equipment damage risk: The instantaneous pressure of cavitation shock wave can reach more than 100 MPa, or even close to 1 GPa, which can easily damage the hydrophone probe 12.

[0087] Key technical parameters:

[0088] Dissolved oxygen (DO) content ≤2 mg / L (based on ISO 5814:2012 standard, monitored in real time using electrochemical probe method).

[0089] Technical implications: Dissolved gases (especially oxygen and nitrogen) are the main source of cavitation nuclei in water. Reducing the oxygen content to ≤2 mg / L (the oxygen content of conventional tap water is about 8-10 mg / L) can significantly increase the acoustic cavitation threshold of the water medium.

[0090] Implementation method: It is achieved through a multi-stage vacuum degassing tower (working vacuum degree ≤5kPa), supplemented by nitrogen bubbling replacement process to accelerate the removal of dissolved oxygen.

[0091] 3. The technical necessity of collaborative processing

[0092] The ultra-high filtration accuracy (0.0001 microns) of the water filtration unit 2 and the ultra-low oxygen content (≤2mg / L) of the vacuum degassing unit 3 work together to provide sufficient and necessary conditions for accurate and safe measurement of high sound pressure (>25 MPa) sound fields: after dual deep processing, the cavitation threshold of the water medium is >25MPa, which can suppress the cavitation phenomenon in the working state of the therapeutic HIFU transducer.

[0093] Here are some specific implementation examples:

[0094] Example 1: Acoustic focus scanning of a high sound pressure level (HIFU) transducer (20MPa)

[0095] Water treatment process: Tap water is treated by water filtration unit 2, and the output water resistivity is 18.2 MΩ·cm (ultrapure water); the ultrapure water enters vacuum degassing unit 3, and under the vacuum degree of 3 kPa and nitrogen bubbling assistance, the output dissolved oxygen content is 1.6 mg / L; the treated water medium is injected into water tank 9.

[0096] Measurement results: The sound pressure signal waveform acquired by oscilloscope 5 is pure and free of high-frequency glitches (cavitation noise is effectively suppressed); the -6dB focal area fluctuation calculated by computer system 1 is <3% (compared to >50% fluctuation in untreated water medium).

[0097] Example 2: Far-field scanning of a non-focused transducer (long-term monitoring)

[0098] Water treatment maintenance: The water medium is circulated and replaced at a flow rate of 2L / min through the inlet / outlet control valve at the bottom of water tank 9 (connected to the output pipe of the water treatment subsystem); real-time monitoring of dissolved oxygen content ≤1.8mg / L (sensor feedback control of degassing unit); cost optimization scheme (applicable to low power): for non-focusing transducer measurement with sound pressure <5MPa, the filtration accuracy can be relaxed to 0.001 microns + oxygen content ≤5mg / L.

[0099] The key to this water treatment system lies in synergistically improving the purity and dissolved oxygen content of the water medium. The filtration precision must be significantly smaller than the length of the ultrasonic wave being measured to effectively suppress the sound scattering effect; the dissolved oxygen content must be reduced to a level where the acoustic cavitation threshold of the water medium is higher than the maximum operating sound pressure of the transducer under test, which has been verified to be ≤ 3 mg / L.

[0100] The 0.0001-micron filtration accuracy and <2 mg / L dissolved oxygen content (or 1.6 mg / L in the specific example) listed above are the preferred parameter combinations for achieving accurate sound field measurement of high sound pressure focused ultrasonic transducers (e.g., >25 MPa), fully verifying the effectiveness of this technical solution. In practical applications, the parameters can be adjusted according to the specific operating frequency (f) and maximum sound pressure (P0) of the transducer under test. For example, for non-focused transducers with an operating frequency ≤1 MHz and a sound pressure ≤10 MPa, the filtration accuracy can be relaxed to 0.1 microns, and the dissolved oxygen content requirement can be reduced to ≤5 mg / L, still within the scope of this disclosed technical solution and achieving the basic effect of suppressing cavitation interference.

[0101] Optionally, in one embodiment, the inner surface of the water tank 9 is covered with sound-absorbing material.

[0102] In this embodiment, during the ultrasonic field scanning process, the sound waves reflected from the inner wall of the water tank 9 will cause two types of measurement errors:

[0103] Sound field distribution distortion: The superposition of reflected waves and direct sound waves leads to sidelobe elevation (measured sidelobe ratio deterioration of 3-5dB) and focal region deformation;

[0104] Standing wave interference: Fixed interference fringes are formed at specific frequencies (e.g., the fringe amplitude reaches 40% peak-to-peak at 3MHz), completely masking the real sound field.

[0105] To eliminate the aforementioned interference, this embodiment covers the inner surface of the water tank 9 with sound-absorbing material, and achieves acoustic impedance matching (e.g., characteristic impedance ≈ 1.5 × 10⁻⁶). 6 Rayl and viscous dissipation mechanisms increase the absorption rate of incident sound waves to ≥99%.

[0106] The coverage area includes:

[0107] Core areas: bottom of the water tank (100% coverage), four sides (coverage height ≥ water level line + 20mm);

[0108] Optimized area: Sidewall above water surface (coated with a hydrophobic layer, contact angle >150°).

[0109] Here are some specific examples:

[0110] Example 1: Verification of Non-Focused Transducer Far-Field Scanning

[0111] Structural configuration: 200L large water tank, with 30mm thick polyurethane sound-absorbing panels covering the sides and bottom;

[0112] Test results: The sound pressure fluctuation at a distance of 150mm from the transducer decreased from ±12% to ±2.8%; the sound field reconstruction map eliminated the grid-like standing wave stripes.

[0113] Example 2: Subfocal Suppression of High Sound Pressure FU Transducer

[0114] Problem background: Subfocal reflections cause a deviation of >15% in the calculation of the -6dB focal area;

[0115] Solution: Add a 50mm gradient density sound-absorbing layer to the bottom of the water tank (bottom layer density 2.0g / cm³, top layer 0.6g / cm³).

[0116] Results: The sound pressure level of the subfocal reflection was reduced by 30 dB, and the standard deviation of the repeatability of the focal area measurement was <0.3 mm².

[0117] "Inner surface covered" definition: Sound-absorbing material is permanently fixed to the metal wall of the water tank by bonding, spraying or clipping.

[0118] The core purpose of lining the inner wall of the water tank with sound-absorbing material is to maximize the absorption of incident sound wave energy (absorption rate ≥ 99%) through acoustic impedance matching and viscous dissipation mechanisms, thereby eliminating sound field distortion and standing wave interference caused by wall reflection. The selection of sound-absorbing material (e.g., characteristic impedance close to 1.5 MRayl) and the thickness design need to be optimized for the main measurement frequency band.

[0119] The specific parameters given in the embodiments, such as the polyurethane foam material and the 30mm / 50mm thickness, are preferred solutions for the commonly used operating frequency band of this system (e.g., 1-5 MHz) and typical water tank size, in order to achieve a sound absorption effect of ≥ 99%. Those skilled in the art will understand that other sound-absorbing materials with similar acoustic properties (e.g., rubber-based composite materials, gradient materials) and thicknesses optimized according to the actual water tank size and measurement frequency (e.g., thinner sound-absorbing layers may be needed for >5 MHz high-frequency measurements, and different thicknesses may be needed for different sections of a large water tank), as long as they can effectively suppress wall reflection interference, are all equivalent implementations of the technical solution disclosed herein.

[0120] Optionally, in one specific embodiment, the hydrophone includes any of the following: a high-voltage fiber optic hydrophone for measuring the sound pressure of a focused ultrasonic transducer that is greater than or equal to a sound pressure threshold; a high-sensitivity thin-film hydrophone for far-field scanning of a non-focused transducer; or a ceramic hydrophone for measuring a focused ultrasonic transducer that requires a measurement accuracy error greater than or equal to an error threshold and / or a sensitivity requirement greater than or equal to a sensitivity threshold.

[0121] In this embodiment, the system is equipped with three types of dedicated hydrophones for different sound field measurement scenarios:

[0122] High-pressure resistant fiber optic hydrophone: suitable for high-intensity focused ultrasound (HIFU) measurement scenarios with sound pressure ≥25MPa, avoiding the risk of probe damage;

[0123] High-sensitivity thin-film hydrophone: suitable for far-field scanning of non-focused transducers with sound pressure ≤5MPa or measurement distance ≥100mm, with sensitivity up to 1000mV / MPa, capable of capturing weak signals of -40dB.

[0124] Ceramic hydrophones: for general sound field scanning scenarios where high sound pressure and high sensitivity are not required.

[0125] Installation steps for high-voltage resistant fiber optic hydrophone: Fix the probe to the ceramic holder (impact-resistant structure) of the I-shaped bracket 11; calibrate the probe axis with a laser collimator to ensure that the deviation from the bracket axis is <0.1°; lead out the fiber optic patch cord through the waterproof interface and connect it to the external demodulator.

[0126] High-sensitivity thin-film hydrophone installation steps:

[0127] The probe is embedded with a PTFE damping ring (to suppress mechanical vibration noise); a level is used to calibrate the parallelism between the probe plane and the transducer radiating surface, with an error of <0.5°; the signal line uses a double-shielded twisted-pair cable to connect to the oscilloscope 5.

[0128] The following are some selection and decision-making rules:

[0129] Sound pressure ≥25MPa → High-pressure resistant fiber optic hydrophones must be used;

[0130] Sound pressure ≤ 5MPa and distance ≥ 100mm → High-sensitivity thin-film hydrophones are required.

[0131] Ceramic hydrophones are used in sound field scanning scenarios where high sensitivity and accuracy are not required, meeting the needs of rapid batch testing in production lines. Their core characteristics include: applicable sound pressure range: ≤10 MPa (medium to low sound pressure transducers); single test duration: ≤30 seconds (standardized production line cycle time). The sensitivity threshold can be set to 500±50 mV / MPa, the error threshold can be set to ≤±10%, and the maximum applicable sound pressure is ≤10 MPa.

[0132] The selection of a hydrophone is based on its damage resistance threshold and sensitivity characteristics. The damage resistance threshold must be significantly higher than the peak value of the maximum sound pressure level of the measured sound field to ensure the probe's safety and reliability under high pressure conditions; the sensitivity must meet the signal-to-noise ratio requirements for detecting the lowest target sound pressure level (such as weak far-field signals) at the measurement distance.

[0133] The 25MPa and 5MPa sound pressure thresholds and the 1000 mV / MPa sensitivity index given in the embodiments are typical preferred values ​​combining the performance of current mainstream transducers and the level of hydrophone technology. The technical solution disclosed herein is not limited to these specific threshold values. With the development of hydrophone technology, when new probes capable of withstanding higher sound pressures (e.g., >40 MPa) or possessing higher sensitivity (e.g., >2000 mV / MPa) emerge, they can be directly applied to this system. Similarly, for specific application scenarios (e.g., medium sound pressure fields, such as 10-20 MPa), other types or specifications of hydrophones (e.g., improved piezoelectric ceramic hydrophones) may also meet the measurement requirements, which are also within the scope of this disclosure.

[0134] Optionally, in one specific embodiment, the transducer positioning and moving mechanism 8 includes a base plate, a fixing plate, and a support beam; the base plate is fixed to the frame 6 by a sliding rod; the fixing plate 20 forms an adjustable rigid connection with the base plate through four sets of adjustable fixing components, the adjustable fixing components including a screw 18 and a wing nut 19; the support beam 24 is linked to the fixing plate 20 through two guide shafts 16, and a bubble level 22 is installed on the support beam 24; the support beam 24 is used to fix the ultrasonic transducer 21 to be tested and drive the ultrasonic transducer 21 to be tested to move up and down along the Z-axis.

[0135] In this embodiment, the transducer positioning and moving mechanism 8 is composed of three rigid components:

[0136] Base plate: The mounting reference surface of the mechanism is connected to the linear bearing of the frame 6 through two Ø12mm sliding rods 26 to realize manual translation in the XY plane (stroke ±50mm, positioning accuracy ±0.1mm).

[0137] Fixed plate 20: Horizontal adjustment carrier, size 300×300×15mm (aluminum alloy 6061-T6), which forms an interference fit with the base plate through four sets of adjustable fixing components (H7 / p6).

[0138] Support beam 24: The main body supporting the transducer, which is linked to the flange linear bearing of the fixed plate 20 through two Ø16mm guide shafts 16 to drive the ultrasonic transducer 21 under test to move up and down along the Z-axis (stroke 200mm, repeatability ±0.01mm).

[0139] Core functions:

[0140] Z-axis lifting: Adapts to immersion depths of transducers with diameters of 50-250mm (immersion requirement: the distance between the transducer's radiating surface and the water surface ≥ acoustic focal length + 200mm).

[0141] Horizontal adjustment: Ensure that the perpendicularity error between the transducer radiating surface and the axis of the hydrophone probe 12 is ≤0.1°;

[0142] Planar coarse adjustment: assists the hydrophone in quickly locating the acoustic focus (saving time spent on automatic scanning).

[0143] 2. Technical Specifications for Adjustable Fixing Components

[0144] Component composition (per group):

[0145] Screw 18: M8 fine thread (pitch 0.5mm), penetrating the mounting holes of the base plate and the fixing plate 20;

[0146] Wing nut 19: Divided into upper nut 19a and lower nut 19b, made of stainless steel with embedded nylon 6 / 6 self-locking parts (anti-loosening torque 0.8N·m).

[0147] Leveling operation principle:

[0148] Partially lift the fixed plate → Rotate the lower nut 19b counterclockwise;

[0149] The fixed plate is partially lowered → rotate the upper nut 19a clockwise;

[0150] The four sets of components can be adjusted independently to compensate for the tilt error of the fixing plate by 20 ±2°.

[0151] Single-turn rotation adjustment: 0.02° (corresponding to a height change of 0.05mm).

[0152] 3. Horizontal calibration and lifting actuator

[0153] Bubble level 22: including bubble level 22a and bubble level 22b, installed on the support beam 24 at a distance of ≤10cm from the transducer interface;

[0154] Calibration standard: Centered double bubble (±0.5 division deviation allowed).

[0155] The Z-axis drive unit includes a trapezoidal lead screw 14, a handwheel 13, and guide shafts 16a and 16b. Guide bearings 17a and 17b correspond to guide shafts 16a and 16b, respectively. A trapezoidal nut 15 corresponds to the trapezoidal lead screw 14.

[0156] The installation and operation process includes:

[0157] Step 1: Transducer installation. Clamp the transducer 21 to the bracket beam 24 clamp; tighten the clamp bolts (torque 4.5±0.5N·m).

[0158] Step 2: Leveling (performed before filling with water). Observe the bubble level 22. If the X-axis is offset by 2 divisions in the positive direction, adjust the X-axis positive screw assembly: rotate the lower nut 19b counterclockwise → the fixing plate 20 will rise locally by 1mm; tighten the upper nut 19a clockwise to lock it; re-measure the bubble until it is centered (error ≤ 0.5 divisions).

[0159] Step 3: Z-axis positioning. Rotate handwheel 13 to drive lead screw 14, lowering the transducer below the water surface;

[0160] Submersion requirements: The distance between the transducer radiating surface and the water surface must be greater than or equal to the acoustic focal length plus 200 mm of water depth;

[0161] Lock the guide shaft clamp (to prevent slippage due to its own weight).

[0162] The positioning accuracy and travel of the motion mechanisms (hydrophone positioning and movement mechanisms and transducer positioning and movement mechanisms) are crucial to ensuring the spatial resolution and coverage of the sound field measurement. The accuracy requirements must meet the need for accurate depiction of the minimum focal length (such as the clinically common 1-3 mm focal length) (error < 5% of the focal length); the travel range must be compatible with the maximum size of the transducer under test and the sound field range.

[0163] The specific parameters detailed in the embodiments, such as ±0.001 mm and ±0.005 mm repeatability, 200 mm Z-axis travel, and 50 mm / s maximum speed, are preferred configurations for high-precision scanning (e.g., 0.1 mm stepping) of typical clinical-grade HIFU transducers (approximately 100-250 mm in diameter and 100-200 mm in focal length). The technical solutions disclosed herein are not limited to these specific values. For applications with smaller dimensions and slightly lower precision requirements (such as miniaturized transducers or rapid sampling on production lines), the positioning accuracy can be appropriately relaxed (e.g., ±0.01 mm), the maximum speed can be increased, or a more cost-effective drive solution can be adopted (e.g., stepper motors replacing some servo motors). As long as reliable scanning and positioning of the critical areas of the sound field under test can be achieved, all are within the scope of protection of this disclosure.

[0164] Optionally, in one embodiment, the support beam 24 is used to position the ultrasonic transducer 21 to be tested directly above or below the hydrophone 12.

[0165] In this embodiment, to reproduce the clinical installation scenario of the ultrasound therapy equipment, the support beam 24 is designed with a bidirectional installation structure to achieve two positioning modes of the ultrasound transducer 21 under test relative to the hydrophone 12:

[0166] Directly below: Transducer 21 is installed on the bottom interface of support beam 24 with the radiating surface facing upward, located in the negative Z direction of the vertical axis of hydrophone 12 (simulating a prostate HIFU treatment bed and other under-mounted devices).

[0167] Directly above: The transducer 21 is installed on the top interface of the support beam 24 with the radiating surface facing down, located in the positive Z direction of the vertical axis of the hydrophone 12 (simulating an external shock wave lithotripter and other top-mounted equipment).

[0168] Positioning accuracy requirement: The deviation between the transducer acoustic focus center and the hydrophone probe axis is ≤0.1mm (to ensure the authenticity of clinical sound field reproduction).

[0169] 2. Mechanical structure and precision assurance

[0170] Two-way mounting interface: Top interface: 4×M6 threaded holes for top mounting; Bottom interface: 4×M6 threaded holes for bottom mounting; Coaxiality of repeated installation of the interface ≤0.05mm.

[0171] Symmetrical guidance system: The center distance between the two guide shafts 16 is 120±0.01mm, and they are symmetrically distributed across the probe axis of the hydrophone 12; the clearance of the linear bearing is ≤5μm to eliminate lifting and lowering sway.

[0172] Support beam rigidity design: Material: 7075-T6 aluminum alloy (tensile strength ≥560MPa); stiffening rib thickness: 8mm; maximum deformation: <0.005mm under a load of 20kg.

[0173] Key steps explained:

[0174] Horizontal calibration: Adjust the angle of the fixing plate 20 by using four sets of screws 18 and wing nuts 19 to center the bubble of the bubble level 22 (allowing an error of 0.5 divisions) and ensure that the horizontality of the radiation surface is ≤0.1°;

[0175] Z-axis positioning: Rotate handwheel 13 to drive the support beam to rise and fall, and set the distance between the radiation surface and the tip of the hydrophone probe to 50mm (including 5mm water layer gap, to prevent mechanical collision) by using the scale.

[0176] Optionally, in one specific embodiment, the screw 18 of the adjustable fixing component penetrates vertically through the substrate and the fixing plate 20; the wing nut 19 includes: a first wing nut 19a screwed on the upper surface of the fixing plate 20, and a second wing nut 19b screwed on the lower surface of the fixing plate 20; the adjustable fixing component is used to adjust the horizontal tilt angle of the support beam 24.

[0177] In this step, the adjustable fixing component is the core unit for horizontal adjustment of the transducer positioning and moving mechanism 8, and each component includes:

[0178] Screw 18: M8 fine thread (pitch 0.5mm), perpendicular to the fixing hole of the substrate and the through hole of the fixing plate 20 (perpendicularity ≤0.05°); Figure 4 In this context, screw 18 includes screw 18a, screw 18b, screw 18c, and screw 18d, which will not be described in detail here.

[0179] First butterfly nut 19a: screwed onto the upper surface of the fixing plate 20, made of stainless steel with nylon 66 embedded self-locking parts;

[0180] Second wing nut 19b: screwed onto the lower surface of the fixing plate 20, made of the same material as 19a.

[0181] The four sets of components are distributed at the four corners of the fixed plate 20 (center distance 250×250mm). By independently adjusting the height of each point, the horizontal tilt angle of the support beam 24 can be adjusted (range ±2°, accuracy 0.02°).

[0182] Optionally, in one specific embodiment, the hydrophone positioning and moving mechanism 7 includes a first automatic adjustment unit; the first automatic adjustment unit includes a first servo motor for driving a first ball screw to move the hydrophone positioning and moving mechanism 7 horizontally; the transducer positioning and moving mechanism 8 includes a second automatic adjustment unit; the second automatic adjustment unit includes a second servo motor for driving a second ball screw to move the transducer positioning and moving mechanism 8.

[0183] In this embodiment, the system achieves high-precision automated positioning of the motion mechanism through closed-loop control of servo motors and ball screws.

[0184] Hydrophone positioning and moving mechanism 7: Equipped with a first servo motor driving the first ball screw 10 (see...) Figure 3 This enables the hydrophone 12 to perform precise scanning motion along the X / Y / Z axes (repeatability ±0.001mm, maximum speed 50mm / s). For example, refer to... Figure 2 The magnified view of a local location 80 in the image. Figure 5 As shown, guide shaft assembly 25 and guide shaft assembly 26, and wing bolts 23a and wing bolts 23b can lock the movement of bushings on guide shaft assembly 25 and guide shaft assembly 26 after tightening.

[0185] Transducer positioning and moving mechanism 8: Equipped with a second servo motor to drive a second ball screw, realizing automatic lifting and positioning of transducer 21 along the Z-axis (repeat positioning accuracy ±0.005mm, maximum speed 20mm / s).

[0186] Technical advantages (compared to manual / stepper motor solutions):

[0187] Motion smoothness: Servo motor torque fluctuation <±2%, eliminating acoustic jets caused by stepper motor jitter (noise reduced to <25dB(A));

[0188] Positioning reliability: The ball screw preload is 8% of the rated dynamic load, eliminating backlash (backlash error ≤ 0.001mm).

[0189] Example of automatic control process:

[0190] Computer system 1 sends the target coordinates (e.g., X=10.000mm, Y=5.000mm, Z=20.000mm) to the first servo motor via EtherCAT bus; the motor drives the first ball screw 10 to move the hydrophone bracket, and the 23-bit encoder provides real-time position feedback; when the deviation between the actual position and the target position is ≤0.001mm, a synchronization signal is triggered to the oscilloscope 5 to collect the sound pressure; the computer records the coordinates and sound pressure values ​​and executes the next scan point. The computer sends the Z-axis target position (e.g., Z=50.000mm) to the second servo motor via Modbus RTU; the motor drives the second ball screw to raise and lower the bracket beam 24; the 20-bit encoder confirms the position is in place (error ≤0.005mm) and sends a completion signal.

[0191] While specific embodiments of this disclosure have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this disclosure is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this disclosure, but all such changes and modifications fall within the scope of protection of this disclosure.

Claims

1. A scanning system for the acoustic field of an ultrasonic transducer, characterized in that, The scanning system includes: a computer system, an oscilloscope, a water treatment subsystem, and a scanning mechanism; The scanning mechanism includes: a frame, a water tank, a hydrophone positioning and moving mechanism, a transducer positioning and moving mechanism, and a hydrophone; The frame serves as the overall load-bearing structure; The water tank is used to hold the water medium provided by the water treatment subsystem; The hydrophone positioning and moving mechanism is mounted on the frame and is used to support the hydrophone and drive the hydrophone to perform three-dimensional motion. The transducer positioning and moving mechanism is installed on the frame and is used to support the ultrasonic transducer to be tested and adjust the spatial orientation of the ultrasonic transducer to be tested. The oscilloscope is connected to the hydrophone, which is used to convert the acquired sound pressure signal into an electrical signal. The oscilloscope is used to receive the electrical signal and process the electrical signal before transmitting it to the computer system. The computer system is connected to the hydrophone positioning and moving mechanism of the scanning mechanism via a motion control interface, and to the oscilloscope via a data acquisition interface, and is used to perform scanning control and sound field modeling. The water treatment subsystem consists of a water filtration unit and a vacuum degassing unit connected in series. The water treatment subsystem is used to provide water medium that meets preset standards to the water tank.

2. The scanning system according to claim 1, characterized in that, The water filtration unit is used to remove suspended solids and ions with a particle size greater than or equal to 0.0001 micrometers from the water; The vacuum degassing unit is used to reduce the oxygen content of the water medium to below 2 mg / L.

3. The scanning system according to claim 1, characterized in that, The inner surface of the water tank is covered with sound-absorbing material.

4. The scanning system according to claim 1, characterized in that, The hydrophone includes any one of the following: High-pressure resistant fiber optic hydrophone, used for measuring the sound pressure of a focused ultrasonic transducer that is greater than or equal to the sound pressure threshold; High-sensitivity thin-film hydrophone for far-field scanning of non-focusing transducers; Ceramic hydrophones are used for measurements of focused ultrasonic transducers where the measurement accuracy error requirement is greater than or equal to an error threshold, and / or the sensitivity requirement is greater than or equal to a sensitivity threshold.

5. The scanning system according to claim 1, characterized in that, The transducer positioning and moving mechanism includes a base plate, a fixing plate, and a support beam. The substrate and the frame are fixed by a sliding rod; The fixing plate is connected to the base plate in an adjustable rigid connection through four sets of adjustable fixing components, the adjustable fixing components including screws and wing nuts; The support beam is linked to the fixed plate through two guide shafts, and a bubble level is installed on the support beam; The support beam is used to fix the ultrasonic transducer under test and drive the ultrasonic transducer under test to move up and down along the Z-axis.

6. The scanning system according to claim 5, characterized in that, The support beam is used to position the ultrasonic transducer to be tested directly above or below the hydrophone.

7. The scanning system according to claim 5, characterized in that, The screw of the adjustable fixing component penetrates vertically through the base plate and the fixing plate; the wing nut includes: a first wing nut screwed on the upper surface of the fixing plate and a second wing nut screwed on the lower surface of the fixing plate; the adjustable fixing component is used to adjust the horizontal tilt angle of the support beam.

8. The scanning system according to claim 1, characterized in that, The hydrophone positioning and moving mechanism includes a first automatic adjustment unit; the first automatic adjustment unit includes a first servo motor, which drives a first ball screw to move the hydrophone positioning and moving mechanism horizontally. The transducer positioning and moving mechanism includes a second automatic adjustment unit; the second automatic adjustment unit includes a second servo motor, which drives a second ball screw to move the transducer positioning and moving mechanism.

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