Dual-frequency ultrasonic transducer with imaging and power output capabilities

Abstract

The application discloses a dual-frequency ultrasonic transducer with imaging and power output capabilities, comprising a high-frequency matching layer, a high-frequency piezoelectric layer, a filter layer, a low-frequency piezoelectric layer, a reverse matching layer and a backing layer. The high-frequency piezoelectric layer and the low-frequency piezoelectric layer can simultaneously generate or receive ultrasonic waves with different frequencies, thereby being used for treatment or imaging. The high-frequency matching layer, the filter layer, the reverse matching layer and the backing layer can improve the ultrasonic wave emission efficiency of the ultrasonic transducer, thereby improving the treatment effect, reducing the heating condition of the ultrasonic transducer and prolonging the service life of the ultrasonic transducer. The filter layer can block high-frequency ultrasonic waves from entering the subsequent structure, thereby avoiding the imaging artifact problem and improving the imaging effect. The application has a wide application prospect in the fields of ultrasonic treatment and ultrasonic imaging.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic transducer technology, and in particular to a dual-frequency ultrasonic transducer that simultaneously possesses imaging and power output capabilities. Background Technology

[0002] Cancer is a major disease that seriously threatens human survival. Chemotherapy is the main treatment for most cancers in clinical practice, but it also has some problems. In recent years, in order to solve these problems, ultrasound-assisted chemotherapy technology has been widely developed, such as "acoustic cluster therapy" to enhance drug delivery and "ultrasound cavitation therapy" to enhance blood flow.

[0003] A major problem with chemotherapy is drug resistance; after multiple chemotherapy sessions, the rate at which chemotherapy drugs are delivered into the tumor decreases. Research indicates that "acoustic cluster therapy" can enhance drug delivery rates. This therapy involves injecting microdroplets and microbubble clusters during chemotherapy, then using high-frequency ultrasound to induce the microdroplets to vaporize into large bubbles, followed by low-frequency ultrasound to excite the large bubbles to oscillate. This exerts pressure on the blood vessel walls, increasing vascular permeability and thus enhancing the delivery rate of chemotherapy drugs. In a 2022 study on mice, Serina Ng et al. found that acoustic cluster therapy increased the chance of complete remission in pancreatic ductal adenocarcinoma by 7.2 times compared to traditional chemotherapy.

[0004] Another major problem with chemotherapy is that some tumors have poorly vascularized areas, making it difficult for chemotherapy drugs to reach these areas via the bloodstream. Research has shown that "ultrasound cavitation therapy" can enhance blood flow. This therapy involves injecting microbubbles during chemotherapy, then using low-frequency ultrasound to stimulate the microbubbles, creating a cavitation effect that induces inflammation and dilation of blood vessels, thereby enhancing blood flow. During treatment, high-frequency ultrasound imaging is used to monitor the treatment area in real time to ensure safety. In 2016, Georg Dimcevski et al. found in the treatment of pancreatic cancer patients that ultrasound cavitation therapy nearly doubled the median survival compared to traditional chemotherapy.

[0005] Besides chemotherapy, high-intensity focused ultrasound (HIFU) is also a treatment method for tumors. It is a non-invasive treatment technique that works by focusing ultrasound waves onto tumor tissue, causing high temperatures that kill tumor cells without affecting surrounding healthy tissue. Throughout the treatment, high-frequency ultrasound imaging can be used to monitor the treatment effect in real time and ensure safety. Currently, this technology is widely used in the clinical treatment of tumors.

[0006] The aforementioned treatments for tumors all require the use of ultrasound transducers to generate or receive ultrasound waves. An ultrasound transducer is a device that uses the piezoelectric effect to convert electrical energy into sound energy or vice versa. Currently, commonly used ultrasound transducers generally contain only one piezoelectric layer and operate only near their resonant frequency. However, the aforementioned treatments require the use of two ultrasound waves at different frequencies. Clearly, an ultrasound transducer with a single resonant frequency cannot meet this requirement.

[0007] While using two ultrasonic transducers with different resonant frequencies can meet the above requirements, using two transducers not only results in a large overall size, but also leads to poor overlap of the ultrasonic sound fields in the working area when they operate simultaneously, thus affecting the treatment effect and the location of the imaging area. To solve this problem, a vertically stacked dual-frequency ultrasonic transducer can be used, where a high-frequency piezoelectric layer and a low-frequency piezoelectric layer are stacked together in the vertical direction. However, if the high-frequency piezoelectric layer and the low-frequency piezoelectric layer are directly bonded together, the received high / low-frequency ultrasonic waves will pass through the high / low-frequency piezoelectric layer, be reflected by the subsequent structure of the transducer, and then re-enter the high / low-frequency piezoelectric layer, where they are received again, causing signal aliasing and resulting in artifacts in the imaging.

[0008] In 2015, Jianguo Ma et al. fabricated a dual-frequency ultrasound transducer capable of both high-frequency and low-frequency imaging by using a filter layer to eliminate high-frequency imaging artifacts and a high-attenuation backing layer to eliminate low-frequency imaging artifacts. However, because the high-attenuation backing layer absorbed the energy of the backward-transmitted low-frequency ultrasound waves, energy loss occurred, resulting in weak low-frequency ultrasound output capability of the dual-frequency ultrasound transducer, which could not adequately meet the requirements for tumor treatment. Summary of the Invention

[0009] The purpose of this invention is to provide a dual-frequency ultrasonic transducer that simultaneously possesses imaging and power output capabilities, thereby solving the problem in the prior art that existing dual-frequency ultrasonic transducers cannot eliminate imaging artifacts while also possessing power output capabilities.

[0010] To achieve the above objectives, the present invention provides a dual-frequency ultrasonic transducer that simultaneously possesses imaging and power output capabilities, comprising, from top to bottom, a high-frequency matching layer, a high-frequency piezoelectric layer, a filter layer, a low-frequency piezoelectric layer, an anti-matching layer, and a backing layer.

[0011] The high-frequency piezoelectric layer is used to generate or receive high-frequency ultrasonic waves;

[0012] The low-frequency piezoelectric layer is used to generate or receive low-frequency ultrasonic waves;

[0013] The high-frequency matching layer is used to improve the transmittance of the high-frequency ultrasound.

[0014] The filter layer is used to conduct the low-frequency ultrasonic waves and block the high-frequency ultrasonic waves; the filter layer, the high-frequency matching layer, and the high-frequency piezoelectric layer constitute a low-frequency matching layer to improve the transmittance of the low-frequency ultrasonic waves; the filter layer and the low-frequency piezoelectric layer constitute a high-frequency anti-matching layer to improve the reflectance of the high-frequency ultrasonic waves.

[0015] The anti-matching layer is used to improve the reflectivity of the low-frequency ultrasound.

[0016] The backing layer is used to support the ultrasonic transducer.

[0017] Preferably, the materials of the high-frequency piezoelectric layer include, but are not limited to, piezoelectric ceramics, piezoelectric single crystals, and piezoelectric composite materials; the materials of the low-frequency piezoelectric layer include, but are not limited to, piezoelectric ceramics, piezoelectric single crystals, and piezoelectric composite materials.

[0018] Preferably, the center frequency of the high-frequency ultrasound is 1MHz-20MHz; the center frequency of the low-frequency ultrasound is 0.1MHz-3MHz.

[0019] Preferably, the thickness of the high-frequency piezoelectric layer is 0.2-0.8 times the wavelength of the high-frequency piezoelectric layer's ultrasonic wave, where the wavelength is the wavelength of the high-frequency ultrasonic wave in each material; the thickness of the low-frequency piezoelectric layer is 0.2-0.8 times the wavelength of the low-frequency piezoelectric layer's ultrasonic wave, where the wavelength is the wavelength of the low-frequency ultrasonic wave in each material.

[0020] Preferably, the high-frequency matching layer is a single-layer structure composed of a single material, a multi-layer structure composed of multiple different materials, or a gradient matching structure.

[0021] Preferably, the thickness of each layer of the high-frequency matching layer is 0.02-0.4 times the wavelength of the ultrasonic wave in each high-frequency matching layer, where the wavelength is the wavelength of the high-frequency ultrasonic wave in each material.

[0022] Preferably, the filter layer is a single-layer structure composed of a single material or a multi-layer structure composed of multiple different materials;

[0023] When the filter layer has an N-layer structure, from the high-frequency piezoelectric layer to the low-frequency piezoelectric layer, the layers are sequentially the first filter layer, the second filter layer, the third filter layer, the fourth filter layer, ... the Nth filter layer. The acoustic impedance ratio of the first filter layer to the acoustic impedance ratio of the high-frequency piezoelectric layer is less than 1, the acoustic impedance ratio of the second filter layer to the acoustic impedance ratio of the first filter layer is greater than 1, the acoustic impedance ratio of the third filter layer to the acoustic impedance ratio of the second filter layer is less than 1, the acoustic impedance ratio of the fourth filter layer to the acoustic impedance ratio of the third filter layer is greater than 1, and the acoustic impedance of each subsequent filter layer follows this rule.

[0024] The thickness of each filter layer is 0.01-5 times the wavelength of the ultrasonic wave in each filter layer, where the wavelength is the wavelength of the high-frequency ultrasonic wave in each material.

[0025] Preferably, the anti-matching layer is a single-layer structure composed of a single material or a multi-layer structure composed of multiple different materials;

[0026] When the anti-matching layer has an N-layer structure, from the low-frequency piezoelectric layer to the backing layer, the layers are sequentially the first anti-matching layer, the second anti-matching layer, the third anti-matching layer, the fourth anti-matching layer, and so on to the Nth anti-matching layer. The acoustic impedance of the first anti-matching layer is less than 1 compared to the acoustic impedance of the low-frequency piezoelectric layer. The acoustic impedance of the second anti-matching layer is greater than 1 compared to the acoustic impedance of the first anti-matching layer. The acoustic impedance of the third anti-matching layer is less than 1 compared to the acoustic impedance of the second anti-matching layer. The acoustic impedance of the fourth anti-matching layer is greater than 1 compared to the acoustic impedance of the third anti-matching layer. The acoustic impedance of each subsequent anti-matching layer follows this pattern.

[0027] When the acoustic impedance ratio of the Nth anti-matching layer to the (N-1)th anti-matching layer is greater than 1, the acoustic impedance ratio of the backing layer to the Nth anti-matching layer is less than 1; when the acoustic impedance ratio of the Nth anti-matching layer to the (N-1)th anti-matching layer is less than 1, the acoustic impedance ratio of the backing layer to the Nth anti-matching layer is greater than 1.

[0028] The thickness of each anti-matching layer is 0.01-0.4 times the wavelength of the ultrasonic wave in each anti-matching layer, where the wavelength is the wavelength of the low-frequency ultrasonic wave in each material.

[0029] Preferably, the ultrasonic transducer can be expanded into a one-dimensional array, a two-dimensional array, a ring array, a convex array, and a concave array.

[0030] The dual-frequency ultrasonic transducer of the present invention, which simultaneously possesses imaging and power output capabilities, has the following technical advantages:

[0031] 1. It can simultaneously transmit / receive high-frequency ultrasonic waves and low-frequency ultrasonic waves, and the sound fields of the high-frequency ultrasonic waves and low-frequency ultrasonic waves overlap.

[0032] 2. When emitting ultrasonic waves, the high-frequency matching layer improves the transmittance of high-frequency ultrasonic waves, and the high-frequency anti-matching layer, composed of the filter layer and the low-frequency piezoelectric layer, improves the reflectivity of high-frequency ultrasonic waves. This allows more high-frequency ultrasonic energy to be emitted, improving the emission efficiency of high-frequency ultrasonic energy, reducing the heat generation of the ultrasonic transducer, and extending its service life. Similarly, the low-frequency matching layer, composed of the high-frequency matching layer, the filter layer, and the high-frequency piezoelectric layer, improves the transmittance of low-frequency ultrasonic waves, and the anti-matching layer improves the reflectivity of low-frequency ultrasonic waves. This allows more low-frequency ultrasonic energy to be emitted, improving the emission efficiency of low-frequency ultrasonic energy, reducing the heat generation of the ultrasonic transducer, and extending its service life.

[0033] 3. When receiving ultrasound, the high-frequency matching layer improves the transmittance of high-frequency ultrasound, thereby allowing more high-frequency ultrasound energy to be received by the high-frequency piezoelectric layer, thus improving the receiving sensitivity of high-frequency ultrasound energy; the low-frequency matching layer composed of the high-frequency matching layer, the filter layer, and the high-frequency piezoelectric layer improves the transmittance of low-frequency ultrasound, thereby allowing more low-frequency ultrasound energy to be received by the low-frequency piezoelectric layer, thus improving the receiving sensitivity of low-frequency ultrasound energy.

[0034] 4. When receiving ultrasonic waves, in traditional ultrasonic transducers, the received high / low frequency ultrasonic waves pass through the high / low frequency piezoelectric layer, are reflected by the subsequent structure of the ultrasonic transducer, and re-enter the high / low frequency piezoelectric layer, where they are again received, causing signal aliasing and resulting in artifacts in the imaging. In the ultrasonic transducer of this invention, the high-frequency anti-matching layer, composed of a filter layer and a low-frequency piezoelectric layer, increases the reflectivity of high-frequency ultrasonic waves, thereby blocking them from passing through the high-frequency piezoelectric layer into the subsequent structure, reducing signal aliasing, and weakening artifacts in the imaging. Similarly, in the ultrasonic transducer of this invention, the anti-matching layer increases the reflectivity of low-frequency ultrasonic waves, thereby blocking them from passing through the low-frequency piezoelectric layer into the subsequent structure, reducing signal aliasing, and weakening artifacts in the imaging.

[0035] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a dual-frequency ultrasonic transducer that simultaneously possesses imaging and power output capabilities according to the present invention.

[0037] Figure 2 This is a schematic diagram of the structure of an ultrasonic transducer obtained in Embodiment 1 of the present invention, which has both imaging and power output capabilities.

[0038] Figure 3This is a circuit diagram of the KLM model simulation of the ultrasonic transducer obtained in Embodiment 1 of the present invention, which has both imaging and power output capabilities.

[0039] Figure 4 This is a simulation result of the sound pressure on the surface of the ultrasonic transducer when it outputs high-frequency ultrasonic waves, according to Embodiment 1 of the present invention, which has both imaging and power output capabilities.

[0040] Figure 5 This is a simulation result of the sound pressure on the surface of the ultrasonic transducer when the ultrasonic transducer outputs low-frequency ultrasonic waves, according to Embodiment 1 of the present invention, which has both imaging and power output capabilities.

[0041] Figure 6 The figures (a) and (b) are time-domain simulation results of the pulse echo response of the high-frequency piezoelectric layer of the ultrasonic transducer obtained in Embodiment 1 of the present invention, which has both imaging and power output capabilities.

[0042] Figure 7 This is a schematic diagram of the structure of a one-dimensional dual-frequency ultrasonic transducer array obtained in Embodiment 2 of the present invention, which simultaneously possesses imaging and power output capabilities.

[0043] Figure 8 This is a schematic diagram of the structure of a two-dimensional dual-frequency ultrasonic transducer array obtained in Embodiment 2 of the present invention, which has both imaging and power output capabilities.

[0044] Figure Labels

[0045] 1. High-frequency matching layer; 2. High-frequency piezoelectric layer; 3. Filter layer; 4. Low-frequency piezoelectric layer; 5. Anti-matching layer; 6. Backing layer; 7. Ultrasonic transducer; 8. Signal source; 9. Signal source internal resistance; 10. Receiver source internal resistance; 11. First high-frequency matching layer; 12. Second high-frequency matching layer; 51. First anti-matching layer; 52. Second anti-matching layer. Detailed Implementation

[0046] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components.

[0048] Example 1

[0049] like Figure 2As shown, a dual-frequency ultrasonic transducer with both imaging and power output capabilities is described. The ultrasonic transducer 7 includes a first high-frequency matching layer 11, a second high-frequency matching layer 12, a high-frequency piezoelectric layer 2, a filter layer 3, a low-frequency piezoelectric layer 4, a first anti-matching layer 51, a second anti-matching layer 52, and a backing layer 6 arranged sequentially from front to back.

[0050] The high-frequency piezoelectric layer 2 is used to generate or receive high-frequency ultrasonic waves, and the low-frequency piezoelectric layer 4 is used to generate or receive low-frequency ultrasonic waves.

[0051] When emitting ultrasound, the high-frequency piezoelectric layer 2 and the low-frequency piezoelectric layer 4 of the transducer can be excited simultaneously to generate high-frequency ultrasound and low-frequency ultrasound. They will be superimposed in the space of interest to form dual-frequency ultrasound for treatment.

[0052] When emitting ultrasonic waves, the high-frequency matching layer 1, composed of the first high-frequency matching layer 11 and the second high-frequency matching layer 12, improves the transmittance of high-frequency ultrasonic waves, and the high-frequency anti-matching layer, composed of the filter layer 3, improves the reflectivity of high-frequency ultrasonic waves. This allows more high-frequency ultrasonic energy to be emitted, improving the emission efficiency of high-frequency ultrasonic energy, reducing the heat generation of the ultrasonic transducer 7, and extending the service life of the ultrasonic transducer 7. The low-frequency matching layer, composed of the first high-frequency matching layer 11, the second high-frequency matching layer 12, the high-frequency piezoelectric layer 2, and the filter layer 3, improves the transmittance of low-frequency ultrasonic waves, and the low-frequency anti-matching layer, composed of the first anti-matching layer 51 and the second anti-matching layer 52, improves the reflectivity of low-frequency ultrasonic waves. This allows more low-frequency ultrasonic energy to be emitted, improving the emission efficiency of low-frequency ultrasonic energy, reducing the heat generation of the ultrasonic transducer 7, and extending the service life of the ultrasonic transducer 7.

[0053] When receiving ultrasonic waves, the high-frequency matching layer 1, composed of the first high-frequency matching layer 11 and the second high-frequency matching layer 12, improves the transmittance of high-frequency ultrasonic waves, thereby allowing more high-frequency ultrasonic energy to be received by the high-frequency piezoelectric layer 2, thus improving the receiving sensitivity of high-frequency ultrasonic energy. The low-frequency matching layer, composed of the first high-frequency matching layer 11, the second high-frequency matching layer 12, the high-frequency piezoelectric layer 2, and the filter layer 3, improves the transmittance of low-frequency ultrasonic waves, thereby allowing more low-frequency ultrasonic energy to be received by the low-frequency piezoelectric layer 4, thus improving the receiving sensitivity of low-frequency ultrasonic energy.

[0054] When receiving ultrasonic waves, in traditional transducers, the received high / low frequency ultrasonic waves pass through the high / low frequency piezoelectric layer, are reflected by the subsequent structure of the transducer, and then re-enter the high / low frequency piezoelectric layer, where they are received again, causing signal aliasing and resulting in artifacts in the imaging. For the transducer in this embodiment, the high-frequency anti-matching layer composed of the filter layer 3 and the low-frequency piezoelectric layer 4 increases the reflectivity of high-frequency ultrasonic waves, thereby blocking them from passing through the high-frequency piezoelectric layer 2 into the subsequent structure, reducing signal aliasing, and weakening artifacts in the imaging. For the ultrasonic transducer 7 in this embodiment, the anti-matching layer composed of the first anti-matching layer 51 and the second anti-matching layer 52 increases the reflectivity of low-frequency ultrasonic waves, thereby blocking them from passing through the low-frequency piezoelectric layer 4 into the subsequent structure, reducing signal aliasing, and weakening artifacts in the imaging.

[0055] In this embodiment, the ultrasonic transducer 7 is cylindrical with a surface radius of 7.5 mm and is used underwater.

[0056] Both the low-frequency piezoelectric layer 4 and the high-frequency piezoelectric layer 2 are made of piezoelectric ceramic PZT4. The center frequency of the low-frequency ultrasound is 0.5MHz, and the thickness of the low-frequency piezoelectric layer 4 is 3.99mm. The center frequency of the high-frequency ultrasound is 4.95MHz, and the thickness of the high-frequency piezoelectric layer 2 is 0.43mm.

[0057] The high-frequency matching layer 1 is a double-layer structure composed of two different materials. The layer furthest from the high-frequency piezoelectric layer 2 is the first high-frequency matching layer 11, and the layer closest to the high-frequency piezoelectric layer 2 is the second high-frequency matching layer 12. The first high-frequency matching layer 11 is made of epoxy resin with an acoustic impedance of 2.4 MRayl and a thickness of 0.117 mm. The second high-frequency matching layer 12 is made of 1 μm tungsten powder mixed with epoxy resin, with an acoustic impedance of 8.9 MRayl and a thickness of 0.089 mm.

[0058] The filter layer 3 is made of epoxy resin, with an acoustic impedance of 2.4 MRayl and a thickness of 0.131 mm.

[0059] The anti-matching layer 5 is a double-layer structure composed of two different materials. The layer closer to the low-frequency piezoelectric layer 4 is the first anti-matching layer 51, and the layer farther away from the low-frequency piezoelectric layer 4 is the second anti-matching layer 52. The first anti-matching layer 51 is made of epoxy resin with an acoustic impedance of 2.4 MRayl and a thickness of 1.150 mm. The second anti-matching layer 52 is made of iron with an acoustic impedance of 45.4 MRayl and a thickness of 2.950 mm.

[0060] The backing layer 6 is made of 15μm alumina with an acoustic impedance of 6.5MRayl and a thickness of 20mm.

[0061] The performance of the ultrasonic transducer 7 in this embodiment was simulated using the KLM model. The peripheral circuits used in the simulation are as follows: Figure 3 As shown. Signal source 8 outputs a Burst signal with a peak-to-peak voltage of 2Vpp and a cycle count of 15. The internal resistance of signal source 9 is 50Ω. The internal resistance of receiver 10 is 50Ω.

[0062] When the ultrasonic transducer 7 outputs high-frequency ultrasonic waves, the voltage frequency output by the signal source 8 is 4.95MHz. The simulation results of the sound pressure on the surface of the ultrasonic transducer 7 are as follows: Figure 4 As shown.

[0063] When the ultrasonic transducer 7 outputs low-frequency ultrasonic waves, the voltage frequency output by the signal source 8 is 0.5MHz. The simulation results of the sound pressure on the surface of the ultrasonic transducer 7 are as follows: Figure 5 As shown.

[0064] The time-domain simulation results of the pulse echo response of the high-frequency piezoelectric layer 2 of the ultrasonic transducer 7 are as follows: Figure 6 As shown in (a), the spectrum is as follows: Figure 6 As shown in (b), the transducer has a sensitivity of 15.4 mV / V and a -6 dB relative bandwidth of 59%.

[0065] Example 2

[0066] A dual-frequency ultrasonic transducer array possessing both imaging and power output capabilities is disclosed. The shape of each single-element ultrasonic transducer is a rectangular prism, and the structural parameters of each layer are the same as those in Example 1. This single-element ultrasonic transducer is then expanded into a one-dimensional dual-frequency ultrasonic transducer array through a one-dimensional array, as shown below. Figure 7 As shown, it can be used for treatment and imaging. This single-element ultrasound transducer can be expanded into a two-dimensional dual-frequency ultrasound transducer array through a two-dimensional array, as shown... Figure 8 As shown, it can be used for treatment and imaging.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dual-frequency ultrasonic transducer with both imaging and power output capabilities, characterized in that, It includes a high-frequency matching layer, a high-frequency piezoelectric layer, a filter layer, a low-frequency piezoelectric layer, an anti-matching layer, and a backing layer, designed sequentially from top to bottom; The high-frequency piezoelectric layer is used to generate or receive high-frequency ultrasound waves; the low-frequency piezoelectric layer is used to generate or receive low-frequency ultrasound waves; when emitting ultrasound waves, the high-frequency piezoelectric layer and the low-frequency piezoelectric layer of the transducer are simultaneously excited to generate high-frequency ultrasound waves and low-frequency ultrasound waves, which are superimposed in the space of interest to form dual-frequency ultrasound waves for treatment. The high-frequency matching layer is used to improve the transmittance of the high-frequency ultrasound. The filter layer is used to conduct the low-frequency ultrasonic waves and block the high-frequency ultrasonic waves; the filter layer, the high-frequency matching layer, and the high-frequency piezoelectric layer constitute a low-frequency matching layer to improve the transmittance of the low-frequency ultrasonic waves; the filter layer and the low-frequency piezoelectric layer constitute a high-frequency anti-matching layer to improve the reflectance of the high-frequency ultrasonic waves. The anti-matching layer is used to improve the reflectivity of the low-frequency ultrasound waves; the backing layer is used to support the ultrasound transducer. The filter layer is a multi-layer structure composed of various different materials; When the filter layer has an N-layer structure, from the high-frequency piezoelectric layer to the low-frequency piezoelectric layer, the layers are sequentially the first filter layer, the second filter layer, the third filter layer, the fourth filter layer, and the Nth filter layer. The acoustic impedance ratio of the first filter layer to the acoustic impedance ratio of the high-frequency piezoelectric layer is less than 1, the acoustic impedance ratio of the second filter layer to the acoustic impedance ratio of the first filter layer is greater than 1, the acoustic impedance ratio of the third filter layer to the acoustic impedance ratio of the second filter layer is less than 1, the acoustic impedance ratio of the fourth filter layer to the acoustic impedance ratio of the third filter layer is greater than 1, and the acoustic impedance of each subsequent filter layer follows this rule. The thickness of each filter layer is 0.01-5 times the wavelength of the ultrasonic wave in each filter layer, where the wavelength is the wavelength of the high-frequency ultrasonic wave in each material. The anti-matching layer is a multi-layer structure composed of various different materials; When the anti-matching layer has an N-layer structure, from the low-frequency piezoelectric layer to the backing layer, the layers are sequentially the first anti-matching layer, the second anti-matching layer, the third anti-matching layer, the fourth anti-matching layer, and the Nth anti-matching layer. The acoustic impedance of the first anti-matching layer is less than 1 compared to the acoustic impedance of the low-frequency piezoelectric layer. The acoustic impedance of the second anti-matching layer is greater than 1 compared to the acoustic impedance of the first anti-matching layer. The acoustic impedance of the third anti-matching layer is less than 1 compared to the acoustic impedance of the second anti-matching layer. The acoustic impedance of the fourth anti-matching layer is greater than 1 compared to the acoustic impedance of the third anti-matching layer. The acoustic impedance of each subsequent anti-matching layer follows this rule. When the acoustic impedance ratio of the Nth anti-matching layer to the (N-1)th anti-matching layer is greater than 1, the acoustic impedance ratio of the backing layer to the Nth anti-matching layer is less than 1; when the acoustic impedance ratio of the Nth anti-matching layer to the (N-1)th anti-matching layer is less than 1, the acoustic impedance ratio of the backing layer to the Nth anti-matching layer is greater than 1. The thickness of each anti-matching layer is 0.01-0.4 times the wavelength of the ultrasonic wave in each anti-matching layer, where the wavelength is the wavelength of the low-frequency ultrasonic wave in each material.

2. A dual-frequency ultrasonic transducer with both imaging and power output capabilities according to claim 1, characterized in that, The high-frequency piezoelectric layer is made of piezoelectric ceramics, piezoelectric single crystals, and piezoelectric composite materials; the low-frequency piezoelectric layer is made of piezoelectric ceramics, piezoelectric single crystals, and piezoelectric composite materials.

3. A dual-frequency ultrasonic transducer with both imaging and power output capabilities according to claim 1, characterized in that, The center frequency of the high-frequency ultrasound is 1MHz-20MHz; the center frequency of the low-frequency ultrasound is 0.1MHz-3MHz.

4. A dual-frequency ultrasonic transducer with both imaging and power output capabilities according to any one of claims 1 to 3, characterized in that, The thickness of the high-frequency piezoelectric layer is 0.2-0.8 times the wavelength of the high-frequency piezoelectric layer ultrasonic wave, where the wavelength is the wavelength of the high-frequency ultrasonic wave in each material; the thickness of the low-frequency piezoelectric layer is 0.2-0.8 times the wavelength of the low-frequency piezoelectric layer ultrasonic wave, where the wavelength is the wavelength of the low-frequency ultrasonic wave in each material.

5. A dual-frequency ultrasonic transducer with both imaging and power output capabilities according to claim 1, characterized in that, The high-frequency matching layer can be a single-layer structure made of a single material, a multi-layer structure made of multiple different materials, or a gradient matching structure.

6. A dual-frequency ultrasonic transducer with both imaging and power output capabilities according to claim 1 or 5, characterized in that, The thickness of each layer of the high-frequency matching layer is 0.02-0.4 times the wavelength of the ultrasonic wave in each high-frequency matching layer, where the wavelength is the wavelength of the high-frequency ultrasonic wave in each material.

7. A dual-frequency ultrasonic transducer with both imaging and power output capabilities according to claim 1, characterized in that, The ultrasonic transducer is expanded into one-dimensional array, two-dimensional array, ring array, convex array, and concave array through array expansion.

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