High-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function

Abstract

The present invention relates to a high-frequency underwater acoustic information sensing array with multiplexing of a sensor element backplane and a signal conditioning function, comprising a sensor element, a rigid PCB signal conditioning board with multi-channel copper electrodes arranged in a central area, a common ground electrode, a preamplifier circuit module, an output electrical connector plug, an output electrical connector socket, a polyurethane perfusion layer, a housing, a base, and a watertight connector. The rigid PCB signal conditioning board is circular, and the sensor element comprises a piezoelectric copolymer film and a multi-channel copper electrode array. The multi-channel copper electrode array is in-situ inlaid along the diameter direction of the rigid PCB signal conditioning board, and the copper electrodes of different channels of the multi-channel copper electrode array are electrically insulated. The present invention utilizes a multifunctional multiplexing method of a rigid signal conditioning board to realize the precise arrangement of multiple array elements of a high-frequency acoustic information sensing array, so as to ensure the high consistency of capacitance and sensitivity of each array element, as well as the accurate control of the array element spacing, so as to ensure the effective perception and pickup of the acoustic information sensing array for high-frequency weak underwater acoustic information.

Description

Technical Field

[0001] The invention relates to the technical field of underwater acoustic transducers, and in particular to a high-frequency underwater acoustic information sensing array with multiplexing of a sensor element backplane and a signal conditioning function. Background Art

[0002] High-frequency sonar is an important form of sonar equipment, and the acoustic information perception array is the core device of high-frequency sonar to realize the acoustic information pickup function. High-frequency sonar is mainly used in scenes such as seabed topography mapping, high-precision acoustic imaging, and marine biological behavior observation. It usually faces problems such as weak target signals, complex background noise, and strong reverberation. In order to improve the information resolution capability, the high-frequency acoustic information perception array equipped with sonar should have the characteristics of a large number of array elements, small spacing, compact layout, and high integration with signal conditioning circuits. This actually puts extremely high demands on the consistency of the array elements of the high-frequency acoustic information perception array.

[0003] In order to meet the needs of high-frequency sonar applications, the sensor elements currently selected for high-frequency receiving arrays are mainly piezoelectric ceramics, type 1-3 piezoelectric composite materials, piezoelectric polymers, etc. There are problems such as too many components, complicated and cumbersome processes, large assembly errors, and insufficient phase and amplitude consistency between array elements when using piezoelectric ceramics as sensor elements to make high-frequency receiving arrays. For example, the high-frequency broadband multi-beam receiving array proposed in Chinese patent 202111492675.9, its receiving array elements are composed of piezoelectric ceramics and matching layers, and decoupling layers are set between adjacent receiving array elements and between the positive electrode surface of the piezoelectric ceramic and the base. The receiving array elements and the decoupling layer are arranged on the base, and the base is installed on the electronic compartment, and the receiving array is integrally encapsulated with polyurethane. Its piezoelectric ceramics and matching layers are discretely connected and assembled rather than integrated to form an array. It is necessary to assemble decoupling layers between adjacent receiving array elements and between the positive electrode surface of the piezoelectric ceramic and the base, resulting in a more complex array structure, more contact surfaces between the components, and a relatively complex assembly process.

[0004] Type 1-3 piezoelectric composite materials are used as sensor elements to make high-frequency receiving arrays. Since the piezoelectric phase of the piezoelectric composite material and the polymer phase that plays a decoupling role are combined through high-precision slicing and filling, the piezoelectric phase particles have good consistency as array elements. However, there are also difficulties in the preparation of piezoelectric phase particle electrodes and leads. In addition, multiple piezoelectric composite materials are usually required to be combined to form an array. At this time, the performance difference between the composite materials becomes a key limiting factor affecting the consistency of the array.

[0005] Chinese patent 201210562947.2 discloses a high-frequency close-packed piezoelectric film hydrophone array, which uses PVDF piezoelectric film, brass small particle backing plate, multi-layer PCB board, etc. to form a two-dimensional plane array. It is arranged through the processing steps of grooving, sandblasting, and pre-forming of the entire brass backing plate. The process complexity is high, and the array integration is still relatively low. At the same time, the thickness of the PVDF piezoelectric film is limited, and the sensitivity of the array element is relatively low. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high-frequency underwater acoustic information sensing array with multiplexing of a sensor element backplane and a signal conditioning function, so as to solve the problem of high consistency between array elements under the requirement of narrow array element spacing of the high-frequency underwater acoustic information sensing array, and to realize the precise arrangement of multiple array elements of the high-frequency acoustic information sensing array by using the multifunctional multiplexing method of a rigid signal conditioning board, so as to ensure high consistency of capacitance and sensitivity of each array element, and accurate control of array element spacing, so as to ensure the effective perception and pickup of high-frequency weak underwater acoustic information by the acoustic information sensing array.

[0007] The technical solution of the present invention is to provide a high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function, including sensor element, rigid PCB signal conditioning board with multi-channel copper electrodes arranged in the central area, common ground electrode, preamplifier circuit module, output electrical connector plug, output electrical connector socket, polyurethane perfusion layer, housing, base, watertight O-ring, watertight connector, wherein:

[0008] The rigid PCB signal conditioning board is circular, and the sensing element includes a piezoelectric copolymer film and a multi-channel copper electrode array. The multi-channel copper electrode array is in-situ inlaid along the diameter direction of the rigid PCB signal conditioning board, and the copper electrodes of different channels of the multi-channel copper electrode array are electrically insulated; positioning holes for positioning the sensing element are arranged near the multi-channel copper electrode array, and a grounded printed circuit is arranged on the back of the rigid PCB signal conditioning board at the location of the positioning holes; preamplifier circuit modules of each channel are arranged on both sides of the multi-channel copper electrode array in a staggered distribution manner on the front and back sides of the rigid PCB signal conditioning board, and the outputs of the preamplifier circuit modules are respectively merged to the output electrical connector sockets on both sides away from the multi-channel copper electrode array through the printed circuit;

[0009] The piezoelectric copolymer film is polarized along the thickness direction, one side of the piezoelectric copolymer film is tightly bonded to a multi-channel copper electrode array, the copper electrode serves as an electrical signal output electrode, and the other side of the piezoelectric copolymer film is bonded to a conductive layer, the conductive layer serves as a common ground electrode and is connected to a ground circuit;

[0010] The shell is circular, the rigid PCB signal conditioning board is installed on the shell, the watertight connector is installed on the base, polyurethane is poured on the side with the sensor element to form a polyurethane perfusion layer, the side without the sensor element is connected to the watertight connector through the output electrical connector plug and the corresponding welding connecting wire, and the shell and the base are watertightly matched through a watertight O-ring.

[0011] Preferably, the copper electrodes of different channels of the copper electrode array are isolated by an insulating layer of a rigid PCB signal conditioning board.

[0012] Preferably, the housing is provided with a fixing groove, and the rigid PCB signal conditioning board is installed in the fixing groove.

[0013] Preferably, the array elements are arranged at half wavelength, the operating frequency is set to 125 kHz, the hydrophone element spacing is 6 mm, and the effective sensing area of ​​the hydrophone element is 24 mm×5.4 mm.

[0014] Preferably, the piezoelectric copolymer film is a P (VDF-TrFE) piezoelectric copolymer film, and the film thickness is 600 μm-800 μm.

[0015] Preferably, the film thickness is 800 μm.

[0016] Preferably, the piezoelectric copolymer film is combined in a whole-film covering manner, and the film size is not less than 32 mm×200 mm.

[0017] Furthermore, the size of the conductive layer is the same as that of the piezoelectric copolymer film, and the material is a conductive rubber sheet, a thin copper sheet, a thin layer of carbon fiber composite material or a conductive tape.

[0018] The present invention proposes to design and manufacture a discrete multi-channel copper electrode array in situ in the central area of ​​a rigid PCB signal conditioning board, and to form a sensing element with a piezoelectric copolymer film of uniform thickness, so that the rigid PCB signal conditioning board plays the role of a backplane of the sensing element, and to closely arrange a multi-channel preamplifier circuit around the sensing area of ​​the same signal conditioning board, so as to realize function multiplexing on the signal conditioning board, thereby simplifying the structure and corresponding manufacturing process of the acoustic information sensing element and array.

[0019] Compared with the high-frequency receiving array based on piezoelectric ceramics, it avoids the problem of array element spacing deviation and array element performance consistency deviation caused by the discrete arrangement of discrete sensor elements, reduces the design of decoupling layer, and can effectively improve the consistency between array elements; compared with the high-frequency dense-line microphone array based on piezoelectric polymer film, it avoids the complex process of brass small particle backing, and uses the piezoelectric copolymer P (VDF-TrFE) film with better piezoelectric performance that does not require stretching orientation as an active sensor element, which can achieve higher array element sensitivity. The present invention can conveniently meet the needs of different frequency arrays by adjusting the array element spacing.

[0020] Compared with the prior art, the present invention has the following advantages after adopting the above scheme:

[0021] (1) The piezoelectric copolymer film sensor element with high piezoelectric performance is used to achieve higher array element sensitivity than the PVDF film receiving array by increasing the film thickness; (2) Through the high integration design of the copper electrode array and multi-channel preamplifier circuit of the rigid PCB signal conditioning board, the sensor element backplane and signal conditioning function of the signal conditioning board are reused, which improves the integrated design capability of the sensor element and the electronic module, fully utilizes the advantages of printed circuits, and improves the reliability of the array; (3) The accuracy of the array element spacing is improved by using mature printed circuit processing, precision machining and other methods, and the array element positioning accuracy is greatly improved by bonding and fixing the entire highly uniform piezoelectric copolymer film, the array element consistency is high, and the entire array structure is further simplified, with outstanding advantages such as light weight and high integration; (4) The high-frequency underwater acoustic information perception array realizes the perception and pickup of 32 channels of acoustic information in one-dimensional direction, with high phase and amplitude consistency of each channel and strong spatial resolution, which can be used for underwater acoustic imaging, marine biological behavior monitoring and other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure after layering of the present invention.

[0024] Figure 3 This is the average sensitivity curve of 32 channels of the high-frequency underwater acoustic information sensing array of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] like Figure 1 , 2 As shown, a high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function includes a P (VDF-TrFE) piezoelectric polymer film 2, a rigid PCB signal conditioning board 3 with multi-channel copper electrodes arranged in the central area, a common ground electrode, a preamplifier circuit module, an output electrical connector plug, an output electrical connector socket 7, a polyurethane perfusion layer 1, a wire, a shell 4, a base 5, a watertight O-ring, and a watertight connector 6.

[0027] The rigid PCB signal conditioning board 3 is basically circular in shape. It adopts a high-integration design concept. A multi-channel copper electrode array 8 is arranged and separated in situ along the diameter direction. The multi-channel copper electrode array 8 and the P (VDF-TrFE) piezoelectric polymer film 2 form a sensing element. The copper electrodes of different channels are electrically insulated and isolated by the insulating layer of the rigid PCB signal conditioning board 3. Positioning holes for positioning the P (VDF-TrFE) piezoelectric polymer film are arranged near the multi-channel copper electrode array 8. A grounded printed circuit is arranged on the back of the rigid PCB signal conditioning board 3 at the location of the positioning holes. Preamplifier circuit modules of each channel are arranged on both sides of the multi-channel copper electrode array 8 in an interlaced distribution manner on the front and back sides of the rigid PCB signal conditioning board 3, and the output of the preamplifier circuit module is respectively merged to the output electrical connector sockets 7 on both sides away from the multi-channel copper electrode array 8 through the printed circuit. Through this design method, the rigid PCB signal conditioning board 3 plays the two functions of the sensor element backing board and signal amplification and conditioning at the same time, which greatly simplifies the array structure and subsequent assembly process.

[0028] The P(VDF-TrFE) piezoelectric copolymer film 2 as the core active sensing element is polarized along the thickness direction, has no electrodes on the front and back sides, and is tightly bonded and fixed to the multi-channel copper electrode array 8 of the rigid PCB signal conditioning board by using the whole film, that is, the P(VDF-TrFE) piezoelectric polymer film 2 is covered by the whole film, and the film size is not less than 32mm×200mm. In this embodiment, the film thickness is 800μm. The multi-channel copper electrode is used as the electrical signal output electrode, and the other side of the P(VDF-TrFE) piezoelectric copolymer film 2 is tightly bonded with a conductive layer, which serves as a common ground electrode and is fixed by screws at the positioning holes and connected to the ground circuit. In this embodiment, the size of the conductive layer is the same as that of the P(VDF-TrFE) piezoelectric copolymer film 2, and the material is a whole conductive rubber sheet. The bonding method is pressurized bonding, and the position is determined by the positioning hole and the matching positioning pin. After the bonding and fixing, the ground circuit on the back of the rigid PCB signal conditioning board 3 is connected at the positioning hole by screws and nuts.

[0029] The housing 4 is also circular, the rigid PCB signal conditioning board 3 is mounted on the housing 4, the watertight connector 6 is mounted on the base 5, polyurethane is poured on the side with the sensor element to form a polyurethane perfusion layer 1 to complete the watertight layer molding, and the side without the sensor element is connected to the watertight connector 6 through the output electrical connector plug and the corresponding welding connection wire, and the housing 4 and the base 5 are watertightly matched through a watertight O-ring to achieve a watertight effect.

[0030] In this embodiment, the P (VDF-TrFE) piezoelectric copolymer film 2 is fixed to the multi-channel copper electrode array 8 on the rigid PCB signal conditioning board 3 by pressurized bonding, and the position is determined by the positioning holes and the matching positioning pins.

[0031] The high-frequency underwater acoustic information sensing array proposed by the present invention, which multiplexes the sensor element backplane and the signal conditioning function, is arranged linearly according to half wavelength, the operating frequency is set to 125kHz, the hydrophone array element spacing is 6mm, and the effective area of ​​a single hydrophone array element is 24mm×5.4mm. This high-frequency underwater acoustic information sensing array can further increase the set operating frequency, that is, reduce the array element spacing.

[0032] The design concept of the present invention can also be extended to a two-dimensional planar sound receiving array, and only the division and manufacturing method of the copper electrode array need to be considered and matched with the arrangement of the multi-channel preamplifier circuit module. Figure 3 32 channels of the high-frequency underwater acoustic information sensing array of this embodiment.

[0033] The present invention proposes to design and manufacture a discrete multi-channel copper electrode array in situ in the central area of ​​a rigid signal conditioning board, and to form a sensing element with a piezoelectric copolymer film of uniform thickness, so that the rigid PCB signal conditioning board plays the role of a backplane of the sensing element, and to closely arrange multi-channel preamplifier circuits around the sensing area of ​​the same signal conditioning board, so as to realize function multiplexing on the signal conditioning board, thereby simplifying the structure and corresponding manufacturing process of the acoustic information sensing element and array.

[0034] Compared with the high-frequency receiving array based on piezoelectric ceramics, it avoids the problem of array element spacing deviation and array element performance consistency deviation caused by the discrete arrangement of discrete sensor elements, reduces the design of decoupling layer, and can effectively improve the consistency between array elements; compared with the high-frequency dense-line microphone array based on piezoelectric polymer film, it avoids the complex process of brass small particle backing, and uses the piezoelectric copolymer P (VDF-TrFE) film with better piezoelectric performance that does not require stretching orientation as an active sensor element, which can achieve higher array element sensitivity. The present invention can conveniently meet the needs of different frequency arrays by adjusting the array element spacing.

[0035] The above is only an explanation of the preferred embodiments of the present invention, which should not be construed as a limitation on the claims. Any equivalent structure or equivalent process changes made using the present invention specification are included in the patent protection scope of the present invention.

Claims

1. A high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function, characterized in that: It includes a sensing element, a rigid PCB signal conditioning board, a common ground electrode, a preamplifier circuit module, an output electrical connector plug, an output electrical connector socket, a polyurethane injection layer, a housing, a base, a watertight O-ring and a watertight connector, wherein: The rigid PCB signal conditioning board is circular, and the sensing element includes a piezoelectric copolymer film and a multi-channel copper electrode array. The multi-channel copper electrode array is in-situ inlaid along the diameter direction of the rigid PCB signal conditioning board, and the copper electrodes of different channels of the multi-channel copper electrode array are electrically insulated; positioning holes for positioning the sensing element are arranged near the multi-channel copper electrode array, and a grounded printed circuit is arranged on the back of the rigid PCB signal conditioning board at the location of the positioning holes; preamplifier circuit modules of each channel are arranged on both sides of the multi-channel copper electrode array in a staggered distribution manner on the front and back sides of the rigid PCB signal conditioning board, and the outputs of the preamplifier circuit modules are respectively merged to the output electrical connector sockets on both sides away from the multi-channel copper electrode array through the printed circuit; The piezoelectric copolymer film is polarized along the thickness direction, one side of the piezoelectric copolymer film is tightly bonded to a multi-channel copper electrode array, the copper electrode serves as an electrical signal output electrode, and the other side of the piezoelectric copolymer film is bonded to a conductive layer, the conductive layer serves as a common ground electrode and is connected to a ground circuit; The shell is circular, the rigid PCB signal conditioning board is installed on the shell, the watertight connector is installed on the base, polyurethane is poured on the side with the sensor element to form a polyurethane perfusion layer, the side without the sensor element is connected to the watertight connector through the output electrical connector plug and the corresponding welding connection wire, and the shell and the base are watertightly matched through a watertight O-ring; The piezoelectric copolymer film is a P (VDF-TrFE) piezoelectric copolymer film, and the film thickness is 600 μm-800 μm.

2. The high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function according to claim 1 is characterized in that: The copper electrodes of different channels of the multi-channel copper electrode array are isolated by the insulating layer of the rigid PCB signal conditioning board.

3. The high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function according to claim 1 is characterized in that: The housing is provided with a fixing groove, and the rigid PCB signal conditioning board is installed in the fixing groove.

4. The high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function according to claim 1 is characterized in that: The array elements are arranged at half wavelength, the operating frequency is set to 125kHz, the hydrophone array element spacing is 6mm, and the effective sensing area of ​​the hydrophone array element is 24mm×5.4mm.

5. The high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function according to claim 1 is characterized in that: The film thickness was 800 μm.

6. The high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function according to claim 1 is characterized in that: The piezoelectric copolymer film is combined in a whole-film covering manner, and the film size is not less than 32 mm×200 mm.

7. The high-frequency underwater acoustic information sensing array with multiplexing of sensor element backplane and signal conditioning function according to claim 1 is characterized in that: The size of the conductive layer is the same as that of the piezoelectric copolymer film, and the material is a conductive rubber sheet, a thin copper sheet, a thin layer of carbon fiber composite material or a conductive tape.

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