Sensing device

Abstract

The invention discloses a sensing device which constructs a virtual array based on a delay chamber. A sound delay cavity with a plurality of independent sound wave guide paths is introduced into the front end of a sensing device, effective separation and time delay of original sound signals in the time dimension are achieved, the time resolution of the sensor is remarkably improved, and the sensor is particularly suitable for various sound wave sensing application scenes such as medical imaging, industrial detection and underwater detection and has wide application prospects. Wide application prospects and engineering values are shown.

Description

Technical Field

[0001] This invention belongs to the field of sensors, and more specifically, relates to a sensor device. Background Technology

[0002] Acoustic wave testing is a non-destructive testing technique based on the propagation characteristics of sound waves in materials or media, and it is widely used in medicine, industry, scientific research, and many other fields. In industry, ultrasound and audible sound testing are often used to inspect the quality of welds, detect defects such as cracks and pores in metals or other materials, and image noise sources. In the medical field, ultrasound imaging is an indispensable technology in prenatal checkups and the diagnosis of heart diseases. Furthermore, in scientific research, ultrasound and infrasound technologies are also used to study the microstructure and dynamic behavior of matter. Its basic principle is to use the emission and reception of sound waves to detect the internal structure or surface properties of an object, and to obtain information about the object by analyzing the reflected signals. Acoustic wave testing has advantages such as high sensitivity, high resolution, and being harmless to the human body.

[0003] The core of acoustic wave detection lies in the acoustic wave sensor, which converts electrical energy into mechanical vibration (ultrasound or infrasound) and converts the received mechanical vibration back into electrical signals. When sound waves encounter different media, they undergo reflection, refraction, and scattering. These changes can be captured by the sensor and converted into electrical signals for analysis. Based on the time delay and intensity of the returned signal, the location, size, and type of defects can be determined.

[0004] To achieve higher precision detection, modern high-precision acoustic wave detection equipment typically incorporates multiple acquisition heads and multiple acoustic wave sensors. Comprehensive processing of data from multiple sensors effectively reduces the errors that may arise from a single sensor, improving the accuracy and reliability of the final output signal. This is particularly important for applications requiring high precision.

[0005] However, in some applications, it may be difficult to install multiple sensors due to limitations in device size or the working environment. For example, adding extra sensors may become impractical when performing detection in confined spaces. When multiple sensors operate simultaneously, mutual interference may occur. This interference can be physical (such as the effects of mechanical vibration) or electromagnetic (such as crosstalk between signals). Summary of the Invention

[0006] To address the space and interference issues caused by multiple sensors, this invention provides an acoustic wave sensor consisting of only an acoustic delay chamber and a single acoustic wave sensor, which offers extremely high resolution.

[0007] This invention employs the following technical solution: an acoustic wave sensor, comprising an acoustic delay chamber and a sensor; one end of the delay chamber opens towards and is directly connected to the acoustic wave sensor, while the other end opens towards and connects to an external sound source to collect acoustic signals. The sound source reaches the acoustic wave sensor after being delayed by the acoustic delay chamber; multiple acoustic waveguides are formed within the acoustic delay chamber, each independently propagating the sound source towards the acoustic wave sensor, and arriving at the sensor at different times, with the interval between two adjacent arrival times greater than the signal width of the sound source. Specifically, after the original acoustic wave signal (sound source) passes through the acoustic delay chamber, it is divided into multiple signals in a time sequence, arriving at the acoustic wave sensor at different times. The acoustic wave sensor sequentially receives these time-separated sub-signals, converts each sub-signal into a corresponding electrical signal output, and finally obtains a signal sequence containing multiple discrete time point responses.

[0008] To obtain the aforementioned signals that can be separated in the time domain, different acoustic waveguide lengths, different acoustic waveguide media to achieve different propagation speeds of sound waves, or combinations of length and speed can be used.

[0009] To obtain a signal sequence that can be separated in the time domain (each sub-signal after separation of the original signal is referred to as a time-sequential signal), the waveguide inside the acoustic delay cavity can be designed with the following structures:

[0010]

[0011] In some embodiments of the present invention, using the same acoustic waveguide medium (with the same propagation speed), different acoustic waveguide lengths are used to obtain signal sequences that can be separated in the time domain. Specifically, each time-series signal is a reduced-amplitude acoustic signal with a waveform that remains unchanged and consistent with the sound source, including an acoustic signal width t, a number of pulses n, and an acoustic frequency f consistent with the sound source. Signals that can be separated from each other are those whose arrival time interval between two adjacent time-series signals arriving at the acoustic sensor is at least greater than or equal to the width t of the acoustic signal. In other words, multiple acoustic waveguides in the acoustic delay chamber delay the acoustic waves they transmit at different times, and the time interval of the delay ΔT is greater than or equal to the width t of the acoustic signal.

[0012] Therefore, an acoustic delay chamber with a delay interval equal to the width t of the acoustic signal can be designed. This chamber comprises A acoustic waveguides of different lengths, forming A openings to the sound source. After the sound wave reaches the acoustic delay chamber, it enters each of the A acoustic waveguides. The waveform of the acoustic signal within each waveguide remains unchanged, but its amplitude is reduced to a fraction of the original signal.

[0013] The length of acoustic waveguide 1 is L0. The length Li of the i-th acoustic waveguide is defined as: Li = L0 ± (i-1)ΔL. A positive value indicates that L0 is the shortest waveguide, and a negative value indicates that L0 is the longest waveguide. The signal delay between adjacent waveguides is at least ΔT = t. Taking a real number k greater than or equal to 1, then... Therefore, it can be obtained Where v is the propagation speed of the sound wave in the acoustic waveguide.

[0014] That is, the length of the i-th acoustic waveguide

[0015] In order to completely place the aforementioned acoustic waveguides of different lengths within the acoustic delay chamber, the acoustic waveguides can be designed with geometric features of an Archimedean spiral, a broken labyrinth, or a fractal tree.

[0016] In some embodiments of the present invention, using the same acoustic waveguide length L, different acoustic waveguide media are used to obtain mutually separated timing signals.

[0017] Specifically, in a medium, the speed of sound Where K is the bulk modulus and ρ is the density.

[0018] The total propagation time in waveguide j is v j Let be the average wave velocity in waveguide j.

[0019] To ensure that the delay interval is greater than or equal to the width t of the sound wave signal, t j satisfy Where t1 is the propagation time of the sound wave in waveguide No. 1, a positive value indicates that t1 is the shortest time, and a negative value indicates that t1 is the longest time, k is a real number greater than 1, n is the number of signal pulses, and f is the frequency of the signal.

[0020] Right now,

[0021] It should be noted that, considering the difficulty in accurately finding a filling medium that perfectly matches the propagation speed vj, a layered medium approach can be used in waveguides to control the propagation speed. This involves filling different sections with different materials to obtain the equivalent wave velocity along the entire length of the waveguide. Assume each waveguide is divided into M segments along its length, and the speed of sound in each waveguide is vj. jm Where m is the segment number, ranging from 1 to M. The total propagation time in waveguide j is... Equivalent wave velocity

[0022] When the number of segments is large enough, and the medium is gradually changing, the change in sound velocity is approximately continuous, forming a sound velocity gradient v. j (x), propagation time t j It can be converted into integral form: At this point, as the length of the acoustic waveguide increases, assuming a gradient coefficient of β... j So let v j (x)=v0 / (1±β j x), we get,

[0023]

[0024] The gradient coefficients of the i-th waveguide can be solved.

[0025] In other cases, periodic voids or pillar arrays are constructed within the waveguide to form a phononic crystal, and the lattice constant α is adjusted. j Or adjust the proportion of the medium Adjusting the equivalent speed of sound v j M:

[0026] Equivalent speed of sound Where vs is the sound velocity of the medium within the waveguide. It represents the proportion of non-void dielectric material within the waveguide. Adjusting a j or Make To obtain the j-th waveguide, the following conditions must be met:

[0027] The beneficial effects of this invention are as follows: By introducing an acoustic delay chamber with multiple independent acoustic waveguide paths into the acoustic sensor, this invention achieves effective separation and delay of the original acoustic signal in the time dimension, significantly improving the sensor's temporal resolution and anti-interference capability. This structure does not rely on complex electronic control components; signal time segmentation can be achieved solely through physical acoustic design, offering advantages such as simple structure, high stability, low cost, and ease of integration. Furthermore, this technology is applicable to various acoustic wave applications, including medical imaging, industrial inspection, noise localization, underwater detection, and earthquake monitoring. It can effectively identify multi-path signals in complex environments, improving system accuracy and reliability, demonstrating broad application prospects and engineering value. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of an acoustic delay chamber and an acoustic sensor formed by a set of acoustic waveguides with a certain angle in an embodiment of the present invention. In the figure, acoustic waveguide 1; waveguide wall 10; acoustic sensor 2; and arrows indicate the incident point of the acoustic wave.

[0029] Figure 2 This is a schematic diagram of an acoustic delay chamber and an acoustic sensor formed by an S-shaped curved acoustic waveguide in an embodiment of the present invention. In the figure, acoustic waveguide 1; acoustic sensor 2.

[0030] Figure 3This is a schematic diagram of an acoustic delay chamber and an acoustic sensor formed by a set of acoustic waveguides that form a main channel branch structure in an embodiment of the present invention. In the figure, acoustic waveguide 1; acoustic sensor 2.

[0031] Figure 4 This is a schematic diagram of sound wave signals, where (a) is the separable signal sequence described in this invention, consisting of three sets of sound wave signals; (b) to (d) are the three sound wave signals received by the sound wave sensor in chronological order after time-domain separation.

[0032] Figure 5 This is a schematic diagram of the acoustic delay chamber with an Archimedean spiral structure described in this invention. In the diagram, there is a first acoustic waveguide 11, a second acoustic waveguide 12, and a third acoustic waveguide 13; the central origin is the point where the acoustic wave is incident. The three acoustic waveguides are not on the same plane and have a certain height difference.

[0033] Figure 6 This is a schematic diagram of an acoustic delay chamber and an acoustic sensor with the same waveguide length and filling medium but different filling duty cycles in an embodiment of the present invention, wherein the acoustic waveguide is 1 and the acoustic sensor is 2. Detailed Implementation

[0034] This invention utilizes an acoustic delay chamber with multiple independent acoustic waveguide paths within an acoustic sensor. Upon entry, the original acoustic signal is segmented into multiple sub-signals, which arrive at the sensor or exit along different paths with varying time delays. Due to differences in the length or structure of each waveguide path, the sound wave propagation time varies, thus separating the original single signal into a series of time-sequential, mutually independent pulse signals on the time axis. This physical structure-based acoustic signal time separation mechanism allows the acoustic sensor to receive and convert these sub-signals at different time points, ultimately outputting a sequence of electrical signals containing multiple time-discrete responses. This process not only achieves time-resolved acoustic signal processing but also effectively overcomes the resolution limitations of a single sensor, significantly improving the system's resolution and noise immunity. Therefore, this working principle directly supports the sensor's ability to resolve multi-path signals in complex acoustic environments, enhancing its accuracy and stability in applications such as medical imaging, industrial inspection, and sonar positioning.

[0035] In this application, "signal width" refers to the pulse duration.

[0036] Typically, the delay chamber of this invention can be fabricated by photolithography and etching to create microchannels in a substrate material (such as silicon, glass, quartz, or polymer). The channels are separated by unetched substrate material (i.e., "waveguide walls") to ensure that sound waves propagate within their respective channels and avoid crosstalk.

[0037] Commonly used substrate materials include silicon, silicon dioxide, glass, quartz, or polymers (such as SU-8 and PDMS). These materials must possess good mechanical stability, acoustic properties, and compatibility with micro / nano fabrication processes. The choice of substrate material directly affects the subsequent processing accuracy and the acoustic characteristics of the device. For example, silicon, due to its excellent etchability and mechanical strength, is often used in the fabrication of high-precision acoustic waveguides, while polymer materials, due to their low processing temperature and low cost, have advantages in flexible device or rapid prototyping development. After determining the substrate material, multiple parallel or specifically arranged channel patterns are defined on the material surface using standard micro / nano fabrication processes. This process is typically centered on photolithography. First, the substrate is cleaned to remove surface contaminants, then a layer of photoresist is spin-coated. Next, a pre-designed mask is used for ultraviolet light exposure, causing the photoresist to undergo chemical changes in specific areas. After a development step, the photoresist in the exposed areas is removed, thus forming an etch-resistant pattern corresponding to the acoustic waveguide channels on the substrate surface. This pattern accurately reflects the final channel width, length, and overall topology. The next crucial step is etching, which transfers the pattern from the photoresist to the substrate material, forming a three-dimensional microchannel structure. This process typically employs dry etching techniques, such as inductively coupled plasma reactive ion etching (ICP-RIE), which, due to its high anisotropy, enables channels with vertical sidewalls and high aspect ratios, ensuring good confinement and low scattering loss of acoustic waves during propagation. The etching depth and sidewall roughness must be strictly controlled to guarantee the consistency of each channel and the stability of acoustic performance. After etching, residual photoresist and etching byproducts are removed through a stripping and cleaning process, exposing a clear and clean multichannel structure.

[0038] The cavities formed by these etchings are the prototype of the acoustic waveguide, while the unetched substrate material on both sides and the bottom of the channel naturally constitutes the waveguide walls. To further optimize acoustic performance, the waveguide walls are sometimes surface-treated, such as oxidized, deposited with low-loss thin films, or polished, to reduce interface scattering.

[0039] In some cases, channel filling is crucial for achieving sound velocity modulation and delay. Depending on design requirements, gaseous, liquid, or solid materials are selected as the transmission medium, and the medium is introduced into each channel through methods such as capillary action, spin coating, injection, or chemical vapor deposition. The filling process must ensure that the medium is uniform, bubble-free, and has good interfacial bonding with the waveguide walls. For channels requiring differentiated delays, different densities (or "duty cycles") can be filled. For example, high-density gel can be filled in some channels to reduce the sound velocity, while air can be filled in others to increase it, thus achieving different propagation delays.

[0040] Furthermore, as is common knowledge in the field, the acoustic waveguide described in this invention satisfies that the absolute value of the difference between the acoustic impedance Z1 of the filling medium and the acoustic impedance Z2 of the waveguide wall approaches 1. Theoretically, it can be a combination of a waveguide wall with high acoustic impedance and a filling medium with low acoustic impedance, or a combination of a waveguide wall with low acoustic impedance and a filling medium with high acoustic impedance. The matching selection is made based on the acoustic impedance of the propagation medium between the sound source and the delay chamber in the application scenario. The low acoustic impedance material can be epoxy resin, phenolic resin, or other high-molecular organic compounds and their doped mixtures. The doped mixture of high-molecular organic compounds can be closed-cell microsphere structures such as wave-particle microspheres and polymer microspheres. The low acoustic impedance material can also be liquids such as water and oil and their doped mixtures, gases such as oxygen and nitrogen and their doped mixtures, or doped mixtures of multiple substances mentioned above. The high acoustic impedance material can be metals such as tungsten, platinum, gold, iron, copper, and aluminum and their mixtures, or metal compounds such as tungsten carbide and alumina.

[0041] The acoustic wave sensor used in this application is the core component for realizing sound-to-electric conversion. It receives multiple time-separated acoustic signals after processing in an "acoustic delay chamber," converts these signals into sound-to-electric signals, and outputs them for processing and analysis by subsequent circuits or systems. It can employ piezoelectric sensors, capacitive micromechanical acoustic wave sensors, MEMS resonant acoustic wave sensors, and so on.

[0042] To ensure efficient transmission of acoustic signals between the acoustic sensor and the delay chamber, one of the following coupling methods can be considered:

[0043] (1) Direct bonding: The sensor is directly bonded to the outlet end of the chamber;

[0044] (2) Add an impedance matching material (such as epoxy resin) between the two to improve the sound wave transmission efficiency;

[0045] (3) Fluid coupling, using liquid medium to fill the gap, suitable for high frequency and underwater applications.

[0046] In one application scenario of this invention, multiple acoustic waveguides are used to form multiple channel partitions, each corresponding to a virtual sensor. These multiple channel partitions are combined to form a virtual sensor array, virtually dividing the original single sensor into multiple sensors. When only a single sensor is used, when a signal arrives at the sensor, the sensor outputs a voltage signal through the piezoelectric effect. Since the acoustic signal arrives at the entire surface of the sensor almost simultaneously, only a time-voltage signal appears in the output voltage signal. By performing time inversion on this time-voltage signal, a circle can be obtained with the sensor as the center and the product of propagation time and propagation speed as the radius. This circle represents the set of possible locations where the sound source may appear. When the acoustic signal is divided into multiple sub-signals by the acoustic waveguide in the delay chamber and arrives at the sensor sequentially, the back-end algorithm defines the virtual coordinates of the virtual sensor corresponding to each sub-signal based on the physical structure of the acoustic waveguide, thus obtaining a set of virtual sensor arrays. At this point, time reversal or delay superposition is performed on each virtual sensor to obtain a circle representing the sound source location centered on each virtual sensor. These circles intersect and overlap, forming an intensity distribution; the area with the highest intensity is most likely the sound source. This allows a single sensor to perform the work that originally required an array of sensors, greatly improving sensor resolution. Conversely, a single sensor can also be used as a sound source to radiate multiple acoustic signals with a certain time difference, achieving directional focusing by controlling the delay sequence.

[0047] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise expressly defined.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] Unless otherwise specified, the sound source mentioned in this invention refers to the sound signal entering the delay chamber, also known as the "incident sound signal", "original sound signal" or "input sound signal".

[0052] Case Study 1: Multi-layer Tissue Recognition System for Medical Ultrasound Imaging

[0053] like Figure 1 As shown, in this case, the sound wave frequency is 1MHz, and the acoustic delay chamber contains five independent acoustic waveguide channels. All channels use the same acoustic medium (STG-2 medical-grade silicone) to ensure that the sound velocity in each channel remains consistent at 1000m / s. The waveguide wall 10 is made of steel with a sound velocity of 5900m / s. The lengths of each channel are 10mm, 14.5mm, 19mm, 23.5mm, and 28mm, respectively, with a circular cross-section, a uniform radius of 0.98mm, and a cross-sectional area of ​​3.01mm². 2 The acoustic waveguides are arranged in parallel, with the normal to the incident surface 4 at a 9.5° angle to the waveguide wall. Since all channels are made of the same material and the sound velocity is constant, the difference in signal arrival time is entirely due to the different path lengths. To achieve these waveguides of varying lengths, the waveguides in the delay chamber are bent at a specific angle. The waveguide length can be precisely controlled using trigonometric functions and the bending angle. This design allows tissue echoes from the same depth to be segmented in the time domain, received by a virtual sensor array, and used for image reconstruction, thus improving the lateral resolution of the imaging. Simultaneously, this design amplifies the differences in propagation time between echo signals from different tissue depths, making it easier to distinguish echo signals from different depths, thereby improving the longitudinal resolution of medical images.

[0054] Case Study 2: Multipath Echo Separation Device in Industrial Defect Detection

[0055] like Figure 2 This case study employs three S-shaped curved waveguide channels 1, all using the same high-strength steel to ensure consistent sound velocity. The waveguide walls 10 are made of boron carbide ceramic. The bending radii of the three waveguides 1 are 5mm, 10mm, and 15mm, resulting in progressively increasing propagation path lengths. Despite the complex waveguide shapes, the sound velocity remains constant; therefore, the delay effect primarily stems from the difference in path length. Each channel has a rectangular cross-section (5mm × 2mm), and an ultrasonic sensor 2 (CMUT or PMUT sensor) is integrated at the exit end. This design allows for time separation of reflected signals through structural control without altering material parameters, making it particularly suitable for the precise identification of the shape and location of internal defects in metal components.

[0056] Figure 4 The diagram shows an ultrasonic signal, where (a) is the input acoustic vibration signal, and (b) to (d) are three ultrasonic signals received by the ultrasonic sensor in chronological order after being separated in the time domain by the S-shaped curved waveguide 1 in this embodiment.

[0057] Case Study 3: Underwater Sonar Target Localization System

[0058] like Figure 3 As shown, in this case, the acoustic delay chamber adopts a main channel branch structure, forming a total of 8 sub-channels, creating a tree-like structure. The waveguide walls 10 of all channels are made of corrosion-resistant plastic, ensuring a consistent sound velocity. The lengths of each channel vary slightly, and each end is connected to an ultrasonic sensor 2 (PVDF thin-film based sensor). When sound waves emitted or reflected by an underwater target enter the chamber from different angles, they will choose different channels to propagate and arrive at the sensor at different times due to the different path lengths. This structure not only achieves spatial response differences based on angles but also utilizes path length differences to achieve signal temporal separation, thereby improving the positioning accuracy of underwater targets.

[0059] Case 4: Signal Receiving Module in a Photoacoustic Imaging System

[0060] like Figure 6 As shown, in this case, biological tissue absorbs laser light, exciting an ultrasonic signal, known as a photoacoustic signal. After reaching the acoustic delay chamber, the photoacoustic signal is incident at a certain angle and enters the five waveguides 1 shown in the figure. These five waveguides 1 are filled with epoxy resin with different duty cycles. For the same waveguide length, due to the different duty cycles of the medium, the equivalent sound velocity in each waveguide differs, and they arrive at sensor 1 sequentially. The equivalent sound velocity in waveguide 1 with a large duty cycle is faster than that in waveguide 2 with a small duty cycle. This design allows the photoacoustic signal from the biological tissue to simulate a virtual array of five sensors during image reconstruction, thereby improving image resolution.

Claims

1. A sensor device, characterized in that, It consists of a chamber and an acoustic sensor; the sound source passes through the chamber and reaches the sensor; multiple acoustic waveguides are formed in the chamber, each propagating the sound source to the acoustic sensor and arriving at the acoustic sensor at different times.

2. The sensor device according to claim 1, characterized in that, The time interval between the sound source and the sound sensor after passing through any two different acoustic waveguides in the cavity is greater than the signal width of the sound source.

3. The sensor device according to claim 1, characterized in that, The acoustic sensor is an ultrasonic sensor, an infrasound sensor, an audible sound sensor, or an acoustic sensor of other wavelengths.

4. The sensor device according to claim 1, characterized in that, The waveguide lengths differ and / or the propagation speeds of the sound waves differ.

5. The sensor according to claim 4, characterized in that, The length of the i-th acoustic waveguide Where L0 is the length of the first acoustic waveguide, v is the propagation speed of the acoustic wave in the acoustic waveguide, n is the number of acoustic pulses contained in the acoustic signal source, f is the frequency of the acoustic signal source, and k is the separation coefficient, which takes a value of not less than 1 and represents the degree of separation of the signal.

6. The sensor device according to claim 4, characterized in that, The acoustic waveguide has an Archimedean spiral, a zigzag labyrinth, or a fractal tree geometry, and one end of the chamber opens toward the acoustic sensor and is directly connected to it, while the other end opens toward an external sound source to collect acoustic signals.

7. The sensor device according to claim 4, characterized in that, An acoustic waveguide satisfies the condition that the absolute value of the difference between the acoustic impedance Z1 of the filling medium and the acoustic impedance Z2 of the waveguide wall is approximately equal to the sum of Z1 and Z2, which is close to 1.

8. The sensor device according to claim 4, characterized in that, The incident angle θ of the acoustic signal entering the cavity satisfies θ>arcsin(c1 / c2), and the cross-sectional area a of the acoustic waveguide satisfies a<λ / 2sinθ0, where λ is the wavelength of the acoustic wave, θ0=arcsin(c1 / c2), c1 is the sound velocity of the filling medium, and c2 is the sound velocity of the waveguide wall.

9. The sensor device according to claim 4, characterized in that, When the acoustic waveguide achieves a difference in sound velocity by filling it with different media, the sound velocity of the i-th acoustic waveguide must be satisfied. Where L represents the waveguide length, v1 represents the sound velocity of the medium in the first waveguide, n is the number of sound pulses contained in the sound wave signal source, f is the frequency of the sound wave signal source, and k is the separation coefficient, which takes a value of not less than 1 and represents the degree of separation of the signal.

10. The sensor device according to claim 4, characterized in that, The acoustic waveguides are constructed by filling them with the same medium, and periodic voids or columnar arrays are formed within the waveguides to create phononic crystals with different lattice constants. To achieve a difference in sound velocity, the lattice constant of the i-th waveguide must be satisfied. Where L represents the waveguide length, v0 represents the sound velocity in the medium of the waveguide, and t1 represents the propagation time of the sound wave in the first waveguide. n is the number of sound pulses contained in the sound wave signal source, f is the frequency of the sound wave signal source, and k is the separation coefficient, which takes a value of not less than 1 and represents the degree of separation of the signal.

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