Transducer for pressure-resistant deep-sea high-frequency parametric array and preparation process

Abstract

The invention provides a transducer for a pressure-resistant deep-sea high-frequency parametric array and a preparation process, the transducer comprises a piezoelectric vibrator parametric array, a negative electrode layer, a positive electrode layer, a backing, a matching layer, a shell and a watertight layer, the size of piezoelectric vibrators is determined, the piezoelectric vibrator parametric array is composed of a plurality of piezoelectric vibrators arranged at equal intervals in an array mode, and the piezoelectric vibrator parametric array is composed of a plurality of piezoelectric vibrators arranged at equal intervals in an array mode. The anodes and the cathodes of all the piezoelectric vibrators are connected in parallel through conductive films, and an anode wire and a cathode wire are led out; a back lining is made of a high-pressure-resistant foam material, and one side of the back lining is bonded to a positive electrode layer of the piezoelectric vibrator parametric array; and shell assembling is conducted, and matching layer pouring and watertight layer pouring are conducted. Compared with the prior art, the transducer has the capability of directly working in a 6000m deep sea environment while having excellent acoustic performance, and the pressure-resistant deep sea high-frequency parametric array is simple in manufacturing process, good in consistency and suitable for large-scale manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of transducers, and in particular to a transducer for a pressure-resistant deep-sea high-frequency parametric array and a preparation process thereof. Background Art

[0002] Due to the particularity of water media and the characteristics of ocean detection technology, the most effective method for detecting seafloor sediments is still the shallow layer profile telemetry method based on the principle of hydroacoustics. Shallow layer profile detection (shallow profile detection) technology is mainly used in marine scientific investigations, submarine cable routing detection, port detection, submarine geological structure detection, underwater engineering site selection and daily maintenance, etc., and plays an important and irreplaceable role in marine scientific research, marine engineering and marine development.

[0003] Parametric array technology is one of the typical examples of the successful application of nonlinear acoustics. Compared with traditional linear shallow profiling sonar technology, parametric shallow profiling detection technology has unique technical characteristics and technical advantages: (1) Parametric sonar with a small physical aperture can realize the transmission of low-frequency, broadband, sidelobe-free narrow beam detection signals, making the system unprecedentedly portable while ensuring detection performance; (2) The low-frequency characteristics of the difference frequency detection signal emitted by parametric shallow profiling sonar enable it to detect deeper and shallower strata. The characteristics of broadband signals can make the shallow strata echo signals carry richer detection information, and the narrow detection beam can ensure high lateral detection resolution at greater depths; (3) The technical characteristics of difference frequency narrow beam and no sidelobe greatly reduce The influence of seabed reverberation and environmental noise on the detection results is reduced. When the same signal processing method is used, the shallow profile detection effect and shallow profile mapping quality can be directly improved, and the interference of false formations introduced by side lobes can be avoided to the greatest extent, ensuring the accuracy and reliability of subsequent work such as data interpretation and geoacoustic parameter inversion. (4) The phased control function of parametric sonar can make the shallow profile detection beam always perpendicular to the seabed, so as to achieve better detection effect for complex terrain. (5) The use of phased tilted beam is more conducive to the detection of shallow buried targets, and its electronic beam scanning detection function is also conducive to the rapid realization of target detection and target positioning.

[0004] With the increasing demand for marine development and marine engineering, foreign countries have developed a certain scale of commercial products for the superior performance of parametric shallow-sediment profile detection technology in the past 30 years, and applied it to port construction, waterway measurement, geological survey and military fields. It can be said that parametric shallow-sediment profile detection technology has unique technical advantages and good application prospects, and is an important direction for the development of shallow-sediment profile detection technology in the future.

[0005] Compared with foreign countries, the development of domestic parameter shallow profiling detection technology is still relatively backward, and there are no commercial parameter shallow profiling detection products. The parameter shallow profiling detection systems used by various professional measurement units are mainly imported from abroad, which are not only expensive, but also difficult to maintain the subsequent system, and are not conducive to the in-depth development of parameter shallow profiling application technology research. Therefore, under the general trend of rapid development of international parameter shallow profiling detection technology and equipment research and development, it is urgent to carry out in-depth and systematic technical theoretical research on parameter shallow profiling detection technology.

[0006] In order to meet the domestic equipment needs for parametric shallow-profile detection, technical personnel in this field have developed a transducer for a pressure-resistant deep-sea high-frequency parametric array, which can work directly in deep-sea equipment to achieve higher-precision detection of deep-sea fine stratigraphic structures and buried targets, and provide equipment support for improving domestic parametric shallow-profile detection technology. Summary of the invention

[0007] The technical problem to be solved by the present invention is: in order to overcome the deficiencies in the prior art, the present invention provides a transducer for a pressure-resistant deep-sea high-frequency parametric array and a preparation process.

[0008] The technical solution to be adopted by the present invention to solve its technical problems is: a transducer for a pressure-resistant deep-sea high-frequency parametric array, comprising a piezoelectric vibrator parametric array, a negative electrode layer, a positive electrode layer, a backing, a matching layer, a shell and a watertight layer, wherein the piezoelectric vibrator parametric array is composed of a plurality of piezoelectric vibrators arranged in an array with equal spacing, and the piezoelectric vibrators are made of ceramic materials, and the negative electrode layer is configured as a conductive film coated on the upper surface of the piezoelectric vibrator parametric array, and the negative electrode layer is a conductive material, and the conductive film connects the negative electrodes of all piezoelectric vibrators in parallel and leads out a negative electrode wire; the positive electrode layer is configured as a conductive film coated on the lower surface of the piezoelectric vibrator parametric array. The positive electrode layer is a conductive material. The conductive film connects the positive electrodes of all piezoelectric vibrators in parallel and leads out a positive electrode wire; the backing is configured to be coated on the lower surface of the positive electrode layer; the matching layer is configured to be coated on the upper surface of the negative electrode layer; the shell is configured to have an inner cavity with an upper opening, and the backing, positive electrode layer, piezoelectric vibrator parametric array, negative electrode layer and matching layer are all arranged in the inner cavity; the watertight layer is configured as an outer coating structure that cooperates with the shell, and the watertight layer and the shell together constitute a package for encapsulating the piezoelectric vibrator parametric array, negative electrode layer, positive electrode layer, backing and matching layer in the interior of the package. Specifically, the watertight layer encapsulates the shell and the internal structure of the shell from top to bottom. The piezoelectric vibrator parametric array adopts a nonlinear array method, and there is no filler between the piezoelectric vibrators.

[0009] Furthermore, a first limiting structure is provided between the watertight layer and the shell, the first limiting structure comprising a first annular groove provided on the outer circumference of the shell, and a first convex ring provided on the inner wall of the watertight layer, and when the shell and the watertight layer are matched, the first convex ring is embedded in the first groove. The concave-convex structure is used to limit the position between the shell and the watertight layer, so as to prevent the watertight layer from falling off the shell.

[0010] Furthermore, a second limiting structure is provided on the connection surface between the shell and the matching layer, and the second limiting structure includes a second annular groove provided on the step surface of the shell, and a second convex ring provided on the lower surface of the matching layer, and when the matching layer and the shell are matched, the second convex ring is embedded in the second groove. The concave-convex structure is used to limit the position between the shell and the matching layer, so as to prevent the watertight layer from falling off the shell.

[0011] Furthermore, in order to facilitate the lead-out of the wires, a lead-out portion is provided on the shell below the inner cavity, and a through hole connected to the inner cavity is provided in the lead-out portion, and a watertight connector is provided in the through hole, and the positive wire and the negative wire are led out from the through hole through the watertight connector.

[0012] Furthermore, a plurality of threaded holes for mounting on a panel are provided on the lower end surface of the shell along the circumferential direction.

[0013] Furthermore, the inner cavity of the shell is bonded and fixed to one side of the lower surface of the backing.

[0014] Preferably, the backing is made of high pressure-resistant foam material; the matching layer is made of epoxy resin material; and the shell is made of titanium alloy material.

[0015] A transducer preparation process, used to prepare the above-mentioned transducer for pressure-resistant deep-sea high-frequency parametric array, comprises the following steps: Step 1: Design and fabrication of piezoelectric vibrator parametric array First, the size of the piezoelectric vibrator is optimized according to the operating frequency. In order to meet the operating frequency of 150kHz, it is necessary to optimize the size of the piezoelectric vibrator (i.e., array element), and use the thickness vibration of the array element to avoid its strong coupling vibration area. Since the operating frequency is 150kHz, the thickness of the array element is about 9.5mm. The resonant frequency of the array element is controlled by adjusting the lateral size. When the lateral size is close to the longitudinal vibration size, the coupling vibration is stronger, which is not conducive to the vibration in the thickness direction. Therefore, the lateral size is as small as possible from the thickness direction. At the same time, considering the operability of the preparation and the actual operating frequency, the size of the piezoelectric vibrator is determined. Specifically, the thickness H of the piezoelectric vibrator is 9.83mm, and the lateral size a*b is 4.5mm×4.5 mm, a and b are the side lengths of the cross section of the piezoelectric vibrator, respectively, to reduce the coupled vibration while meeting the frequency requirements; then, in order to ensure a high degree of consistency between the array elements, the large disc of piezoelectric ceramics is cut into small ceramic particles according to a certain size as the piezoelectric vibrators for the array; then, considering the directivity of the narrow beam and the operability of the array process, the spacing d between the centers of the array elements is 5mm. Therefore, the cut piezoelectric vibrators are arranged in an array with a center spacing of d=5mm to form a circular piezoelectric vibrator parametric array with an effective radiation surface size of diameter D=140mm; the positive electrodes of all the piezoelectric vibrators are connected in parallel through a conductive film, and a positive wire is led out; the negative electrodes of all the piezoelectric vibrators are connected in parallel through a conductive film, and a negative wire is led out.

[0016] Step 2: Assembly of the backing Since high-pressure foam materials have the characteristics of high compressive strength, low sound velocity, and low density, high-pressure foam materials are cut according to the designed size to obtain the backing. Using high-pressure foam materials as backing can reduce the overall weight of the transducer, achieve the back decoupling problem of the transducer, and achieve the water pressure resistance of the transducer, which is suitable as the backing material of the transducer. Then, glue is used to bond one side of the backing to the positive electrode layer of the piezoelectric vibrator parametric array, and the glue layer is cured at a curing temperature of 30°C for 4-5 hours.

[0017] Step 3: Assembly of the housing Since titanium alloy materials have the characteristics of low density, high strength, and corrosion resistance, titanium alloy materials are used to process and manufacture the shell according to the designed dimensions. Titanium alloy materials as shells can reduce the overall weight of the transducer, make the transducer resistant to seawater corrosion, and achieve water pressure resistance of the transducer, and are suitable as the shell material of the transducer. A lathe or CNC machining center is used to form an inner cavity on the shell, a first groove is formed on the outer circumferential surface of the shell, a step surface is formed on the shell at the upper end of the inner cavity, and a second groove is formed on the step surface; the radial dimension and axial dimension of the inner cavity of the shell can cover the piezoelectric vibrator parametric array and the backing at the same time, and can meet the radial pressure-bearing requirements; then, an adhesive is applied to the bottom surface of the inner cavity and / or the side of the backing facing away from the piezoelectric vibrator parametric array, the piezoelectric vibrator parametric array and the backing are simultaneously placed in the inner cavity, the backing is bonded to the shell, and at the same time, the positive and negative wires are led out from the through holes of the lead wire outlet portion at the bottom of the shell, and are threadedly connected to the watertight connector on the lead wire outlet portion, and an O-ring groove is provided on the contact surface between the watertight connector and the shell, and sealing is achieved by the O-ring.

[0018] Step 4: Matching layer infusion In order to ensure that the beam width fluctuates within -3dB and obtain a wider bandwidth with a bandwidth range of 130kHz-170kHz, matching layer technology is used to further improve the overall performance of the transducer. The matching layer is made of epoxy resin material. After analysis, the thickness of the matching layer is about 4.0mm.

[0019] Epoxy resin material is poured into the shell above the negative electrode layer to form a matching layer. The epoxy resin material is embedded in the second groove to form a second convex ring on the surface of the matching layer. The upper surface of the matching layer is flush with the upper end of the shell. Preferably, the thickness of the matching layer ranges from 3.98mm to 4.02mm. Then, the poured structure is vacuum treated with a vacuum degree of -0.1MPa for 3min to 5min. After the vacuum treatment, constant temperature curing is performed at a temperature of 30°C for at least 12h.

[0020] After the matching layer is poured, it needs to be vacuumed for a certain period of time to prevent the hiding of air bubbles, and then it needs to be cured at a constant temperature for a long time to ensure the quality of the matching layer pouring.

[0021] Step 5: Parametric Array Watertightness In order to meet the use and performance test of the parametric array in water, its surface is watertight, and the transducer structure obtained in step 4 is placed in a casting mold as a whole, and then polyurethane is cast into the mold to form a watertight layer on the outside of the shell and the matching layer. The thickness of the watertight layer ranges from 5.25mm to 5.35mm, and the preferred thickness of the watertight layer is 5.3mm. After casting the watertight layer, vacuum treatment is performed, the vacuum degree is -0.1MPa, and the time is 5min-6min. After vacuum treatment, constant temperature curing is performed at a temperature of 60℃-65℃ for at least 24h.

[0022] The beneficial effects of the present invention are as follows: the present invention provides a transducer and preparation process for a pressure-resistant deep-sea high-frequency parametric array, the array arrangement adopts a nonlinear array arrangement and a process method without gap filling between array elements, so that the parametric array has excellent acoustic performance; the structural design adopts a radial axial pressure-resistant process, so that the parametric array has the ability to work directly in a 6000m deep-sea environment. It can be applied to higher-precision detection of deep-sea fine stratigraphic structures and buried targets, meeting the needs of marine scientific investigations, submarine cable routing detection, port detection, submarine geological structure detection, underwater engineering site selection and daily maintenance. The manufacturing process is simple, consistent, and suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 It is a schematic diagram of the structure of the transducer used for the pressure-resistant deep-sea high-frequency parametric array of the present invention.

[0025] Figure 2 It is a schematic diagram of the three-dimensional structure of the transducer used for the pressure-resistant deep-sea high-frequency parametric array of the present invention.

[0026] Figure 3 It is a schematic diagram of the cross-sectional structure of the transducer used for the pressure-resistant deep-sea high-frequency parametric array of the present invention.

[0027] Figure 4 yes Figure 3 Schematic diagram of the enlarged structure at point A in the middle.

[0028] Figure 5 It is a structural schematic diagram of the piezoelectric vibrator parameter array.

[0029] Figure 6 It is a schematic diagram of the structure of a piezoelectric vibrator.

[0030] Figure 7 It is a schematic diagram of the structure of the shell.

[0031] Figure 8 It is a schematic diagram of the structure of the shell.

[0032] Fig. 9It is a schematic diagram of the cross-sectional structure of the shell.

[0033] Fig.10 It is a schematic diagram of the structure of the matching layer.

[0034] Fig.11 It is a schematic diagram of the structure of the watertight layer.

[0035] Fig.12 It is the admittance curve diagram of the transducer of the present invention in water.

[0036] Fig.13 It is a high frequency transmission voltage response curve of the transducer of the present invention.

[0037] Fig.14 It is a high frequency receiving sensitivity curve diagram of the transducer of the present invention.

[0038] Fig.15 It is a low-frequency receiving sensitivity curve diagram of the transducer of the present invention.

[0039] Fig.16 It is the 150kHz directivity diagram of the transducer of the present invention.

[0040] In the figure: 1. piezoelectric vibrator parameter array, 1.1. piezoelectric vibrator, 2. negative electrode layer, 3. positive electrode layer, 4. backing, 5. matching layer, 5.1. second convex ring, 6. shell, 6.1. lead outlet, 6.2. threaded hole, 6.3. inner cavity, 6.4. second groove, 6.5. first groove, 6.6. through hole, 6.7. step surface, 7. watertight layer, 7.1. first convex ring, 8. watertight connector. DETAILED DESCRIPTION

[0041] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention, and directions and references (e.g., up, down, left, right, etc.) may only be used to help describe the features in the drawings. Therefore, the following specific embodiments are not to be taken in a limiting sense, and the scope of the subject matter claimed is limited only by the attached claims and their equivalents.

[0042] like Figure 1-Figure 3As shown, a transducer for a pressure-resistant deep-sea high-frequency parametric array of the present invention comprises a piezoelectric vibrator parametric array 1, a negative electrode layer 2, a positive electrode layer 3, a backing 4, a matching layer 5, a shell 6 and a watertight layer 7, wherein the piezoelectric vibrator parametric array 1 is composed of a plurality of piezoelectric vibrators 1.1 arranged in an array with equal spacing, and the piezoelectric vibrators 1.1 are made of a ceramic material, and the negative electrode layer 2 is configured as a conductive film coated on the upper surface of the piezoelectric vibrator parametric array 1, and the negative electrode layer 2 is a conductive material, and the conductive film connects the negative electrodes of all the piezoelectric vibrators 1.1 in parallel and leads out a negative electrode wire; the positive electrode layer 3 is configured as a conductive film coated on the lower surface of the piezoelectric vibrator parametric array 1, and the positive electrode layer 3 is a conductive material, and the conductive film connects all The positive electrodes of the piezoelectric vibrator 1.1 are connected in parallel, and a positive electrode wire is led out; the backing 4 is configured to be coated on the lower surface of the positive electrode layer 3; the matching layer 5 is configured to be coated on the upper surface of the negative electrode layer 2; the shell 6 is configured to have an inner cavity 6.3 with an upper opening, and the backing 4, the positive electrode layer 3, the piezoelectric vibrator parametric array 1, the negative electrode layer 2 and the matching layer 5 are all arranged in the inner cavity 6.3; the watertight layer 7 is configured as an outer coating structure matched with the shell 6, and the watertight layer 7 and the shell 6 together constitute a package body, which is used to encapsulate the piezoelectric vibrator parametric array 1, the negative electrode layer 2, the positive electrode layer 3, the backing 4 and the matching layer 5 in the interior of the package body, and the inner cavity 6.3 of the shell 6 is bonded and fixed to one side of the lower surface of the backing 4. Specifically, the watertight layer 7 encapsulates the shell 6 and the internal structure of the shell 6 from top to bottom. Preferably, the backing 4 is made of high pressure-resistant foam material; the matching layer 5 is made of epoxy resin material; and the shell 6 is made of titanium alloy material.

[0043] like Figure 4 As shown, a first limiting structure is further provided between the watertight layer 7 and the shell 6, and a second limiting structure is provided on the connecting surface between the shell 6 and the matching layer 5, as shown in FIG. Figure 7-Figure 11 As shown, the first limiting structure includes a first annular groove 6.5 provided on the outer circumference of the housing 6, and a first convex ring 7.1 provided on the inner wall of the watertight layer 7. When the housing 6 and the watertight layer 7 are matched, the first convex ring 7.1 is embedded in the first groove 6.5. The second limiting structure includes a second annular groove 6.4 provided on the step surface 6.7 of the housing 6, and a second convex ring 5.1 provided on the lower surface of the matching layer 5. When the matching layer 5 and the housing 6 are matched, the second convex ring 5.1 is embedded in the second groove 6.4.

[0044] like Figure 7-Figure 9As shown, a lead wire outlet portion 6.1 is provided on the housing 6 below the inner cavity 6.3, and a through hole 6.6 communicating with the inner cavity 6.3 is provided in the lead wire outlet portion 6.1, and a watertight connector 8 is provided in the through hole 6.6, and the positive and negative wires are led out from the through hole 6.6 through the watertight connector 8. In this embodiment, the through hole 6.6 is a threaded hole, and the watertight connector 8 is threadedly connected in the through hole 6.6. A plurality of threaded holes 6.2 for installation on a panel are provided on the lower end surface of the housing 6 along the circumferential direction, and the transducer can be installed on the customer's panel through the threaded holes 6.2.

[0045] A transducer preparation process, used to prepare the above-mentioned transducer for pressure-resistant deep-sea high-frequency parametric array, comprises the following steps: Step 1: Design and fabrication of piezoelectric vibrator parametric array 1 First, the size of the piezoelectric vibrator 1.1 is optimized according to the operating frequency. In order to meet the operating frequency of 150kHz, the size of the piezoelectric vibrator 1.1 (i.e., the array element) needs to be optimized, and the thickness vibration of the array element is used to avoid its strong coupling vibration area. Since the operating frequency is 150kHz, the thickness of the array element is about 9.5mm. The resonant frequency of the array element is controlled by adjusting the lateral size. When the lateral size is close to the longitudinal vibration size, the coupling vibration is stronger, which is not conducive to the vibration in the thickness direction. Therefore, the lateral size is as small as possible as that in the thickness direction. At the same time, considering the operability of the preparation and the actual operating frequency, the size of the piezoelectric vibrator 1.1 is determined, such as Figure 5 and Figure 6 As shown, the thickness H of the piezoelectric vibrator 1.1 is 9.83 mm, and the lateral size a*b is 4.5 mm×4.5 mm, where a and b are the side lengths of the cross section of the piezoelectric vibrator 1.1, respectively, to reduce the coupled vibration while meeting the frequency requirements; then, in order to ensure the high consistency between the array elements, the piezoelectric ceramics of the large disc are cut into small ceramic particles according to a certain size as the piezoelectric vibrators 1.1 for arraying; then, considering the directivity of the narrow beam and the operability of the array process, the spacing d between the centers of the array elements is 5 mm, therefore, the cut piezoelectric vibrators 1.1 are arranged in an array with a center spacing of d=5 mm to form a circular piezoelectric vibrator parametric array 1 with an effective radiation surface size of a diameter D=140 mm; the positive electrodes of all the piezoelectric vibrators 1.1 are connected in parallel through a conductive film, and a positive electrode wire is led out; the negative electrodes of all the piezoelectric vibrators 1.1 are connected in parallel through a conductive film, and a negative electrode wire is led out.

[0046] Step 2: Assembly of Backing 4 Since the high-pressure foam material has the characteristics of high compressive strength, low sound velocity, and low density, the high-pressure foam material is cut according to the designed size to obtain the backing 4. In this embodiment, as a preferred embodiment, the size of the backing is: diameter 144mm, height 4.65mm. The use of high-pressure foam material as the backing 4 can reduce the overall weight of the transducer, achieve the back decoupling problem of the transducer, and achieve the water pressure resistance of the transducer. It is suitable as the backing 4 material of the transducer. Then, glue is used to bond one side of the backing 4 to the positive electrode layer 3 of the piezoelectric vibrator parametric array 1, and the glue layer is cured at a curing temperature of 30°C for 4-5 hours.

[0047] Step 3: Assembly of Shell 6 Since titanium alloy material has the characteristics of low density, high strength, and corrosion resistance, titanium alloy material is used to process and manufacture the shell 6 according to the designed size. Titanium alloy material as the shell 6 can reduce the overall weight of the transducer, make the transducer resistant to seawater corrosion, and achieve water pressure resistance of the transducer, and is suitable as the shell 6 material of the transducer. Using a lathe or a CNC machining center, etc., an inner cavity 6.3 is formed in the shell 6, a first groove 6.5 is formed on the outer peripheral surface of the shell 6, a step surface 6.7 is formed on the shell 6 at the upper end of the inner cavity 6.3, and a second groove 6.4 is formed on the step surface 6.7; the radial size and axial size of the inner cavity 6.3 of the shell 6 can simultaneously cover the piezoelectric vibrator parametric array 1 and the backing 4, and can meet the radial pressure requirements. In this embodiment, the radial pressure reaches 72Mpa; then , apply adhesive to the bottom surface of the inner cavity 6.3 and / or the side of the backing 4 facing away from the piezoelectric vibrator parametric array 1, place the piezoelectric vibrator parametric array 1 and the backing 4 into the inner cavity 6.3 at the same time, so that the backing 4 is bonded to the shell 6, and at the same time, the positive and negative wires are led out from the through holes 6.6 of the lead wire outlet portion 6.1 at the bottom of the shell 6, and are threadedly connected to the watertight connector 8 on the lead wire outlet portion 6.1, and an O-ring groove is provided on the contact surface between the watertight connector 8 and the shell 6, and sealing is achieved by the O-ring; Step 4: Matching layer 5 infusion In order to ensure that the beam width fluctuates within -3dB and obtain a wider bandwidth, the matching layer 5 is made of epoxy resin material. After analysis, the thickness of the matching layer 5 is 4.0mm. After the matching layer 5 is poured, it needs to be vacuumed for a certain period of time to prevent the hiding of air bubbles, and then it needs to be cured at a constant temperature for a long time to ensure the quality of the pouring of the matching layer 5.

[0048] Epoxy resin material is poured into the shell 6 above the negative electrode layer 2 to form a matching layer 5. The epoxy resin material is embedded in the second groove 6.4 to form a second convex ring 5.1 on the surface of the matching layer 5. The upper surface of the matching layer 5 is flush with the upper end of the shell 6. Preferably, the thickness of the matching layer 5 ranges from 3.98 mm to 4.02 mm, and the preferred thickness is 4.0 mm. Next, the poured structure is vacuum treated with a vacuum degree of -0.1 MPa for 3 min to 5 min. After the vacuum treatment, constant temperature curing is performed at 30°C for at least 12 h.

[0049] Step 5: Parametric Array Watertightness In order to meet the use and performance test of the parametric array in water, the surface is watertight, and the transducer structure obtained in step 4 is placed in a casting mold as a whole, and then polyurethane is cast into the mold to form a watertight layer 7 outside the housing 6 and the matching layer 5. The thickness of the watertight layer 7 ranges from 5.25 mm to 5.35 mm, and preferably the thickness of the watertight layer 7 is 5.3 mm. After casting the watertight layer, vacuum treatment is performed, the vacuum degree is -0.1 MPa, the time is 5 min to 6 min, and after vacuum treatment, constant temperature curing is performed, the temperature is 60 ° C to 65 ° C, and the time is at least 24 hours.

[0050] The transducer is prepared according to the above process. The transducer array adopts a nonlinear array and a process method without gap filling between array elements, so that the piezoelectric vibrator parametric array has excellent acoustic performance. Then the transducer is tested, and the test results are described as follows: like Fig.12 The figure shows the impedance of the transducer in water at 100kHz-200kHz. The red solid line represents the impedance G curve, the blue dotted line represents the impedance Cp curve, the horizontal axis represents the frequency, the left vertical axis represents G, and the right vertical axis represents Cp. The resonant frequency of the transducer is 150kHz, and the working bandwidth is ≥30kHz.

[0051] like Fig.13 The figure shows the emission voltage response of the transducer at 100kHz-200kHz. The horizontal axis represents the frequency and the vertical axis represents the emission voltage response. The emission voltage response of the transducer at the operating frequency (135kHz-175kHz) is ≥181dB.

[0052] like Fig.14 The figure shows the receiving sensitivity of the transducer at high frequency 100kHz-200kHz, the horizontal axis represents frequency, and the vertical axis represents receiving sensitivity; the receiving sensitivity of the transducer at the resonant frequency of 150kHz is ≥-180dB.

[0053] like Fig.15The figure shows the receiving sensitivity of the transducer at a low frequency of 5kHz-30kHz, where the horizontal axis represents the frequency and the vertical axis represents the receiving sensitivity. The transducer has a flat receiving sensitivity at a low frequency of 5kHz-30kHz.

[0054] like Fig.16 The figure shows the horizontal / vertical directivity diagram of the transducer at a frequency of 150kHz. The -3dB opening angle of the transducer is 4.3°@150kHz.

[0055] From the above tests, we can know that the front matching layer technology is used to make the parametric array work bandwidth ≥30kHz. The radial and axial pressure-resistant process is used in the structural design, so that the parametric array has the ability to work directly in the 6000m deep sea environment: the parametric array has passed the 72MPa water pressure test.

[0056] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the scope of the present invention through the above description. The technical scope of this invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A transducer for a pressure-resistant deep-sea high-frequency parametric array, characterized in that: The invention comprises a piezoelectric vibrator parametric array, a negative electrode layer, a positive electrode layer, a backing, a matching layer, a shell and a watertight layer, wherein the piezoelectric vibrator parametric array is composed of a plurality of piezoelectric vibrators arranged in an array with equal spacing, the negative electrode layer is configured as a conductive film coated on the upper surface of the piezoelectric vibrator parametric array, the conductive film connects the negative electrodes of all the piezoelectric vibrators in parallel and leads out a negative electrode wire; the positive electrode layer is configured as a conductive film coated on the lower surface of the piezoelectric vibrator parametric array, the conductive film connects the positive electrodes of all the piezoelectric vibrators in parallel and leads out a positive electrode wire. The backing is configured to be coated on the lower surface of the positive electrode layer; the matching layer is configured to be coated on the upper surface of the negative electrode layer; the shell is configured to have an inner cavity with an upper opening, and the backing, positive electrode layer, piezoelectric vibrator parametric array, negative electrode layer and matching layer are all arranged in the inner cavity; the watertight layer is configured as an outer coating structure matched with the shell, and the watertight layer and the shell together constitute a packaging body for packaging the piezoelectric vibrator parametric array, negative electrode layer, positive electrode layer, backing and matching layer inside the packaging body.

2. The transducer for a pressure-resistant deep-sea high-frequency parametric array according to claim 1, characterized in that: A first limiting structure is also provided between the watertight layer and the shell. The first limiting structure includes a first annular groove arranged on the outer circumference of the shell, and a first convex ring arranged on the inner wall of the watertight layer. When the shell and the watertight layer are matched, the first convex ring is embedded in the first groove.

3. The transducer for a pressure-resistant deep-sea high-frequency parametric array according to claim 1, characterized in that: A second limiting structure is provided on the connecting surface of the shell and the matching layer. The second limiting structure includes a second annular groove arranged on the step surface of the shell, and a second convex ring arranged on the lower surface of the matching layer. When the matching layer and the shell are matched, the second convex ring is embedded in the second groove.

4. The transducer for a pressure-resistant deep-sea high-frequency parametric array according to claim 1, characterized in that: A lead wire outlet portion is provided on the shell below the inner cavity, a through hole communicating with the inner cavity is provided in the lead wire outlet portion, a watertight connector is provided in the through hole, and the positive and negative wires are led out from the through hole through the watertight connector.

5. The transducer for a pressure-resistant deep-sea high-frequency parametric array according to claim 1, characterized in that: The lower end surface of the shell is provided with a plurality of threaded holes along the circumferential direction for mounting on a panel.

6. The transducer for a pressure-resistant deep-sea high-frequency parametric array according to claim 1, characterized in that: The inner cavity of the shell is bonded and fixed to one side of the lower surface of the backing.

7. The transducer for a pressure-resistant deep-sea high-frequency parametric array according to claim 1, characterized in that: The backing is made of high pressure-resistant foam material; the matching layer is made of epoxy resin material; and the shell is made of titanium alloy material.

8. A transducer preparation process, characterized in that: The method for preparing a transducer for a pressure-resistant deep-sea high-frequency parametric array as claimed in any one of claims 1 to 7 comprises the following steps: Step 1: Design and fabrication of piezoelectric vibrator parametric array First, the size of the piezoelectric vibrator is optimized according to the operating frequency, and the size of the piezoelectric vibrator is determined. The thickness H of the piezoelectric vibrator is 9.83 mm, and the lateral size a*b is 4.5 mm×4.5 mm, where a and b are the side lengths of the cross section of the piezoelectric vibrator respectively; then, the piezoelectric ceramics of the large disc are cut into small ceramic particles according to the determined size as the piezoelectric vibrators for arraying; then, the cut piezoelectric vibrators are arranged in an array according to the center spacing d=5 mm to form a circular piezoelectric vibrator parameter array with an effective radiation surface size of a diameter D=140 mm; the positive electrodes of all the piezoelectric vibrators are connected in parallel through a conductive film, and a positive electrode wire is led out; the negative electrodes of all the piezoelectric vibrators are connected in parallel through a conductive film, and a negative electrode wire is led out; Step 2: Assembly of the backing A high-pressure foam material is cut according to the designed size to obtain a backing, and then one side of the backing is bonded to the positive electrode layer with glue, and the glue layer is cured; Step 3: Assembly of the housing A shell is made of titanium alloy material according to the designed size, so that an inner cavity is formed in the shell, a first groove is formed on the outer peripheral surface of the shell, a step surface is formed on the shell at the upper end of the inner cavity, and a second groove is formed on the step surface; the radial size and axial size of the inner cavity of the shell can simultaneously cover the piezoelectric vibrator parametric array and the backing, and can meet the radial pressure-bearing requirements; then, an adhesive is applied to the bottom surface of the inner cavity and / or the side of the backing facing away from the piezoelectric vibrator parametric array, the piezoelectric vibrator parametric array and the backing are simultaneously placed in the inner cavity, the backing is bonded to the shell, and at the same time, the positive and negative wires are led out from the through holes of the lead wire outlet portion at the bottom of the shell, and are threadedly connected to the watertight connector on the lead wire outlet portion, and an O-ring groove is provided on the contact surface between the watertight connector and the shell, and sealing is achieved by the O-ring; Step 4: Matching layer infusion An epoxy resin material is poured into the shell above the negative electrode layer to form a matching layer, and the epoxy resin material is embedded in the second groove to form a second convex ring on the surface of the matching layer. The upper surface of the matching layer is flush with the upper end of the shell. Preferably, the thickness of the matching layer ranges from 3.98 mm to 4.02 mm. Then, the poured structure is vacuum treated with a vacuum degree of -0.1 MPa for 3 min to 5 min, and then the vacuum treatment is performed at a constant temperature, the temperature is 30° C., and the time is at least 12 h; Step 5: Parametric Array Watertightness The transducer structure obtained in step 4 is placed as a whole in a casting mold, and polyurethane is cast into the mold to form a watertight layer on the outside of the shell and the matching layer. The thickness of the watertight layer ranges from 5.25 mm to 5.35 mm, and the preferred thickness of the watertight layer is 5.3 mm. After casting the watertight layer, vacuum treatment is performed with a vacuum degree of -0.1 MPa for 5 min to 6 min. After vacuum treatment, constant temperature curing is performed at a temperature of 60°C to 65°C for at least 24 h.

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