PVDF circular tube vector hydrophone based on flexible circuit and processing method thereof

Abstract

The invention relates to a PVDF circular tube vector hydrophone based on a flexible circuit and a processing method thereof. The hydrophone comprises a PVDF circular tube, a first flexible circuit, a metal backing, an upper end cover, a lower end cover and a watertight connector, wherein the PVDF round tube is formed by rolling a PVDF film, and a plurality of electrodes are uniformly arranged on the PVDF round tube 1 at intervals along the circumferential surface; the first flexible circuit is used for shielding electromagnetic interference and amplifying signals, a plurality of second electrodes in one-to-one correspondence with the electrodes on the PVDF circular tube are arranged on the first flexible circuit, the second electrodes are correspondingly connected with the electrodes on the PVDF circular tube respectively, and a shielding layer is arranged on the first flexible circuit. According to the invention, the PVDF round tube is rolled by the PVDF film, so that the problem of high difficulty in integral forming of the PVDF round tube can be solved, a large-size PVDF round tube vector hydrophone can be manufactured, and the working frequency of the round tube vector hydrophone is effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrophones, and in particular relates to a PVDF round tube vector hydrophone based on a flexible circuit and a processing method thereof. Background Art

[0002] Since the sound wave propagation loss in the ocean increases sharply with the increase of frequency, it is necessary to expand the working frequency of the sonar system to low frequency in order to achieve long-distance transmission of sound waves. However, with the decrease of working frequency, the array aperture of the hydrophone array composed of traditional sound pressure hydrophones will become larger and larger in order to maintain the original working performance, which will have an adverse effect on the convenience and concealment of deployment, and there is a problem of azimuth ambiguity, which limits its application in practical engineering to a certain extent. As a new type of underwater acoustic measurement equipment, the vector hydrophone can not only measure the sound pressure information in the sound field, but also synchronously and concurrently measure the orthogonal components of vector information such as particle velocity, displacement or acceleration in the sound field, providing more comprehensive sound field information. For the velocity type vector hydrophone, it has a dipole directivity that is independent of frequency, and can also obtain good spatial gain in the low and very low frequency bands. In addition, the small size of the vector hydrophone makes it suitable for both fixed shore-based deployment and rapid and mobile deployment. It is convenient and flexible to use, and can effectively solve the problem of the large size of traditional sonar equipment composed of sound pressure hydrophones.

[0003] Most existing circular tube vector hydrophones use piezoelectric ceramic circular tubes as sensitive elements, but piezoelectric ceramic materials are fragile, difficult to process, and have low sensitivity. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a PVDF circular tube vector hydrophone based on a flexible circuit and a processing method thereof. The present invention adopts the form of rolling a PVDF circular tube with a PVDF membrane to solve the problem of high difficulty in one-piece molding of the PVDF circular tube, and can produce a large-size PVDF circular tube vector hydrophone, effectively reducing the operating frequency of the circular tube vector hydrophone.

[0005] The technical solution of the present invention is to provide a PVDF round tube vector hydrophone based on a flexible circuit, the hydrophone comprising a PVDF round tube, a first flexible circuit, a metal backing, an upper end cap, a lower end cap, and a watertight connector; wherein, The PVDF round tube is made of a rolled PVDF film, and a number of electrodes are evenly spaced along the circumference of the PVDF round tube; The first flexible circuit is used to shield electromagnetic interference and amplify signals. The first flexible circuit is provided with a plurality of second electrodes corresponding to the electrodes on the PVDF round tube. The second electrodes are respectively connected to the electrodes on the PVDF round tube. The first flexible circuit is provided with a shielding layer to prevent the hydrophone receiving signal from being interfered. The metal backing is columnar and supported on the inner side of the PVDF round tube, and the upper end cover and the lower end cover are respectively arranged on the upper and lower ends of the metal backing; The first flexible circuit is electrically connected to the watertight connector; The outside of the hydrophone is also sealed with a watertight layer.

[0006] The PVDF circular tube vector hydrophone based on a flexible circuit proposed in the present invention forms dipole directivity by differentially outputting two signals at relative positions.

[0007] Preferably, a second flexible circuit is further included, and the second flexible circuit is used to connect the first flexible circuit and the watertight connector. The flexible circuit and the sensing component are integrally poured to reduce the sensitivity loss of the hydrophone caused by the introduction of the cable.

[0008] Preferably, four first electrodes are evenly spaced along the circumference of the PVDF circular tube, and correspondingly, four second electrodes corresponding to the electrodes on the PVDF circular tube are provided on the first flexible circuit, and the second electrodes are respectively connected to the electrodes on the PVDF circular tube.

[0009] Preferably, the PVDF round tube is bonded to the metal backing by a clamp.

[0010] Preferably, a threaded hole is provided at the upper end of the metal backing, and a through hole of the same size is provided at the upper end cover. The screw passes through the through hole of the upper end cover and is screwed into the threaded hole of the metal backing to lead out the electrode signal in the PVDF circular tube to the watertight connector.

[0011] Preferably, a boss is provided between the upper end cover and the lower end cover, and the boss is used to be positioned at the upper and lower ends of the metal backing.

[0012] Preferably, the lower end cover is provided with three injection positioning holes.

[0013] Preferably, the watertight layer is made of polyurethane, rubber or epoxy resin material.

[0014] Preferably, the PVDF round tube can be rolled by replacing the PVDF film with piezoelectric ceramics, piezoelectric single crystals or piezoelectric polymer films.

[0015] The present invention also provides a method for processing the PVDF circular tube vector hydrophone based on the above-mentioned flexible circuit, comprising the following steps: Step 1: Print the rectangular PVDF membrane outer electrode in four equal parts; Step 2: The PVDF membrane is divided into four parts with the electrodes facing outwards and bonded to the metal backing surface by a clamp; Step 3: Pressurize and bond the upper end cover and the lower end cover to the two ends of the metal backing, wherein the holes of the upper end cover are aligned with the holes of the metal backing; Step 3: Use screws to pass the metal welding piece with the lead through the hole of the upper end cover and fix it on the metal backing; Step 4: Align the four electrodes inside the first flexible circuit with the electrodes divided into four equal parts outside the PVDF round tube, and press and bond them together using a clamp; Step 5: Connect the soldering leads in step 3 to the second flexible circuit, and the second flexible circuit to the watertight connector; Step 6: Place the parts completed in the above steps into the injection mold and seal them with polyurethane watertight glue.

[0016] Compared with the prior art, the present invention has the following advantages: A PVDF circular tube vector hydrophone based on a flexible circuit proposed in the present invention can achieve directional reception in a small space; a method of making a PVDF circular tube by curling a PVDF film can be used to make a large-sized circular tube hydrophone, thereby reducing the operating frequency of the circular tube vector hydrophone; a method of integrally injecting a flexible circuit and a sensor component can be used to reduce the sensitivity loss of the hydrophone caused by the introduction of cables; a method of having a built-in shielding layer in the flexible circuit can improve the anti-interference ability of the hydrophone. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings: The present invention proposes a PVDF circular tube vector hydrophone based on a flexible circuit, such as Figure 1 As shown, the hydrophone includes a PVDF round tube 1, a first flexible circuit 2, a metal backing 3, an upper end cover 5, a lower end cover 6, and a watertight connector 9; wherein, The PVDF circular tube 1 is made of a rolled PVDF film, and four electrodes are evenly spaced along the circumference of the PVDF circular tube 1; The first flexible circuit 2 is used to shield electromagnetic interference and amplify signals. The first flexible circuit 2 is provided with four second electrodes corresponding to the electrodes on the PVDF round tube. The second electrodes are connected to the electrodes on the PVDF round tube one by one. In order to prevent the hydrophone receiving signal from being interfered, a shielding layer is provided on the first flexible circuit 2. The metal backing 3 is columnar and supported on the inner side of the PVDF circular tube 1. The upper end cap 5 and the lower end cap 6 are respectively arranged at the upper and lower ends of the metal backing 3. The first flexible circuit 2 is electrically connected to the watertight connector 9; The outside of the hydrophone is also sealed with a watertight layer 8.

[0019] In this embodiment, the PVDF round tube 1 and the metal backing 3 are bonded by a clamp; the upper end of the metal backing 3 is provided with a threaded hole, and the upper end cover 5 has a through hole of the same size. The screw 4 passes through the through hole of the upper end cover 5 and is screwed into the threaded hole of the metal backing 3, which is used to lead the electrode signal in the PVDF round tube 1 to the watertight connector 9. In addition, the lower end cover 4 is provided with three injection positioning holes.

[0020] The upper end cap 5 and the lower end cap 6 can be made of non-metallic materials such as polycarbonate, plastic, nylon, etc., and the watertight layer 8 is made of polyurethane, rubber or epoxy resin material. In this embodiment, the upper end cap 5 and the lower end cap 6 are made of nylon material, and the watertight layer 8 is made of polyurethane.

[0021] As an implementation mode, a boss is provided between the upper end cover 5 and the lower end cover 6 , and the boss is used to be positioned at the upper and lower ends of the metal backing 3 .

[0022] As an alternative, the PVDF tube 1 can be rolled by using piezoelectric ceramics, piezoelectric single crystals or piezoelectric polymer films instead of PVDF films.

[0023] Flexible circuits are conventional technology and include a body formed of a flexible material, and electrical traces formed on the body.

[0024] The processing method of PVDF circular tube vector hydrophone based on flexible circuit, the specific steps are as follows: Step 1: Print the rectangular PVDF membrane outer electrode in four equal parts; Step 2: The PVDF membrane is divided into four parts with the electrodes facing outwards and bonded to the metal backing surface by a clamp; Step 3: Pressurize and bond the upper end cover and the lower end cover to the two ends of the metal backing, wherein the holes of the upper end cover are aligned with the holes of the metal backing; Step 3: Use screws to pass the metal welding piece with the lead through the hole of the upper end cover and fix it on the metal backing; Step 4: Align the four electrodes inside the first flexible circuit with the electrodes divided into four equal parts outside the PVDF round tube, and press and bond them together using a clamp; Step 5: Connect the solder tab lead in step 3 to the second flexible circuit, and the second flexible circuit to the watertight connector; Step 6: Place the parts completed in the above steps into the injection mold and seal them with polyurethane watertight glue.

[0025] 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 process changes made using the present invention specification are included in the patent protection scope of the present invention.

Claims

1. A PVDF circular tube vector hydrophone based on a flexible circuit, characterized in that: The hydrophone comprises a PVDF round tube, a first flexible circuit, a metal backing, an upper end cap, a lower end cap, and a watertight connector; wherein, The PVDF round tube is made of a rolled PVDF film, and a plurality of electrodes are evenly spaced along the circumference of the PVDF round tube 1; The first flexible circuit is used to shield electromagnetic interference and amplify signals. The first flexible circuit is provided with a plurality of second electrodes corresponding to the electrodes on the PVDF round tube. The second electrodes are respectively connected to the electrodes on the PVDF round tube. The first flexible circuit is provided with a shielding layer to prevent the hydrophone receiving signal from being interfered. The metal backing is columnar and supported on the inner side of the PVDF round tube, and the upper end cover and the lower end cover are respectively arranged on the upper and lower ends of the metal backing; The first flexible circuit is electrically connected to the watertight connector; The outside of the hydrophone is also sealed with a watertight layer.

2. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 1, characterized in that: Also included is a second flexible circuit, which is used to connect the first flexible circuit and the watertight connector.

3. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 1, characterized in that: Four first electrodes are evenly spaced along the circumference of the PVDF circular tube. Correspondingly, four second electrodes corresponding to the electrodes on the PVDF circular tube are arranged on the first flexible circuit. The second electrodes are respectively connected to the electrodes on the PVDF circular tube.

4. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 1, characterized in that: The PVDF round tube is bonded to the metal backing by a clamp.

5. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 4, characterized in that: A threaded hole is provided at the upper end of the metal backing, and a through hole of the same size is provided at the upper end cover. The screw passes through the through hole of the upper end cover and is screwed into the threaded hole of the metal backing to lead out the electrode signal in the PVDF round tube to the watertight connector.

6. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 5, characterized in that: A boss is arranged between the upper end cover and the lower end cover, and the boss is used for positioning at the upper and lower ends of the metal backing.

7. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 6, characterized in that: The lower end cover 4 is provided with three injection positioning holes.

8. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 5, characterized in that: The watertight layer is made of polyurethane, rubber or epoxy resin materials.

9. The PVDF circular tube vector hydrophone based on flexible circuit according to claim 1, characterized in that: PVDF round tubes can be rolled by replacing PVDF film with piezoelectric ceramics, piezoelectric single crystals or piezoelectric polymer films.

10. A method for processing a PVDF circular tube vector hydrophone based on a flexible circuit according to any one of claims 1 to 9, characterized in that: The following steps are included: Step 1: Print the rectangular PVDF membrane outer electrode in four equal parts; Step 2: The PVDF membrane is divided into four parts with the electrodes facing outwards and bonded to the metal backing surface by a clamp; Step 3: Pressurize and bond the upper end cover and the lower end cover to the two ends of the metal backing, wherein the holes of the upper end cover are aligned with the holes of the metal backing; Step 3: Use screws to pass the metal welding piece with the lead through the hole of the upper end cover and fix it on the metal backing; Step 4: Align the four electrodes inside the first flexible circuit with the electrodes divided into four equal parts outside the PVDF round tube, and press and bond them together using a clamp; Step 5: Connect the solder tab lead in step 3 to the second flexible circuit, and the second flexible circuit to the watertight connector; Step 6: Place the parts completed in the above steps into the injection mold and seal them with polyurethane watertight glue.

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