Preparation method of receiving sensor array, receiving sensor array and imaging sonar

Abstract

The invention relates to a preparation method of a receiving sensing array, the receiving sensing array and an imaging sonar, and the method comprises the steps: enabling a first matching layer to block the matching layer slurry in a process that the matching layer slurry is solidified to form a second matching layer, so as to prevent the matching layer slurry from entering a positioning hole through the permeation of a conductive adhesive tape. The first matching layer and the second matching layer jointly form the matching layer, and the situation that the thickness of the matching layer on the surface of the conductive adhesive tape is insufficient is effectively avoided by ensuring the thickness of the second matching layer.

Description

Technical Field

[0001] This invention relates to the field of imaging sonar, and in particular to a method for preparing a receiving sensor array, the receiving sensor array, and an imaging sonar. Background Technology

[0002] Three-dimensional imaging sonar systems are widely used in fields such as ocean exploration, underwater communication, and non-destructive testing. The two most core components are the sound wave transmitter and the sound wave receiver. The sound wave transmitter emits sound waves towards the imaging target, and the sound waves are received by the sound wave receiver after being reflected by the imaging target, thus forming an image.

[0003] The acoustic receiver mainly consists of a circuit board, a transducer array disposed on the surface of the circuit board, and a matching layer disposed on the transducer array through a potting process. The degree of matching of the structural parameters between the transducer array and the matching layer is crucial to the performance of the acoustic receiver. However, in the actual fabrication process of the acoustic receiver, it has been found that the actual thickness of the matching layer is often much smaller than its designed thickness, resulting in a significant difference between the actual performance of the acoustic receiver and its designed performance, which fails to meet production requirements. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for fabricating a receiving sensor array, a receiving sensor array, and an imaging sonar to address the problem of a large deviation between the actual thickness and the designed thickness of the matching layer.

[0005] A method for fabricating a receiving sensor array, comprising:

[0006] A positioning plate with positioning holes is provided on the front side of the circuit board;

[0007] Place the receiving array element in the positioning hole and electrically connect the receiving array element to the circuit board;

[0008] Conductive adhesive tape is provided on the side of the positioning plate opposite to the circuit board, and the conductive adhesive tape covers the end of the positioning hole.

[0009] A matching layer paste is applied to the side of the conductive tape facing away from the positioning plate. Then the circuit board is transferred into a vacuum chamber and a vacuum is drawn to remove the air from the positioning hole.

[0010] The circuit board is removed from the vacuum chamber, and the first matching layer is formed after the matching layer paste has cured.

[0011] After the first matching layer is formed, the support frame is supported on the mold, and the circuit board is supported on the support frame. The first matching layer is opposite to the mold and spaced apart. A potting gap is left between the circuit board and the inner edge of the support frame.

[0012] A matching layer slurry is injected into the potting gap on the back of the circuit board to allow the matching layer slurry to flow between the circuit board and the mold;

[0013] The mold, the support frame, and the circuit board are transferred into a vacuum chamber, and then a vacuum is drawn to remove the air between the circuit board and the mold.

[0014] The mold, the support frame, and the circuit board are removed from the vacuum chamber, and then a second matching layer is formed after the matching layer slurry between the circuit board and the mold has cured.

[0015] During the process of the matching layer slurry curing to form the second matching layer, the first matching layer blocks the matching layer slurry to prevent it from entering the positioning hole through the conductive tape.

[0016] In one embodiment, the method for fabricating the receiving sensor array further includes:

[0017] Erase clearance holes onto the double-sided tape;

[0018] The positioning plate is bonded to the front of the circuit board using the double-sided adhesive.

[0019] Wherein, the double-sided adhesive avoids the end of the positioning hole and the mounting position on the circuit board through the avoidance hole, the positioning hole and the mounting position correspond one-to-one, and the end of the positioning hole is located at the corresponding mounting position;

[0020] After the positioning plate is bonded to the front of the circuit board, conductive paste is applied to the mounting position through the positioning hole;

[0021] After the receiving array element is placed in the positioning hole, the receiving array element is pressed so that the receiving array element is electrically connected to the mounting position through conductive paste.

[0022] In one embodiment, the matching layer slurry is cured by heating.

[0023] In one embodiment, the matching layer slurry is epoxy resin.

[0024] In one embodiment, the conductive adhesive tape is made of polyester fiber.

[0025] In one embodiment, the receiving array element is clearance-fitted with the sidewall of the positioning hole.

[0026] In one embodiment, the thickness of the first matching layer is less than the thickness of the second matching layer.

[0027] In one embodiment, the receiving array element is made of piezoelectric ceramic.

[0028] A receiving sensor array is prepared by the method described above.

[0029] An imaging sonar includes a housing, a transmitter, and a receiving sensor array, wherein the transmitter and the receiving sensor array are mounted on the housing;

[0030] The transmitter is used to emit sound waves;

[0031] The receiving sensor array is used to receive sound waves reflected from the imaging target.

[0032] The beneficial effects of this invention are as follows:

[0033] During the fabrication of the first matching layer, a pressure balance is maintained between the front and back sides of the circuit board, which effectively prevents deformation of the circuit board.

[0034] Based on this, during the preparation of the second matching layer, the first matching layer effectively prevents the matching layer slurry from entering the positioning holes by blocking the slurry. Thus, at the moment the vacuum chamber door is opened, the matching layer slurry can effectively support the circuit board by utilizing its poor fluidity, limiting the deformation of the circuit board.

[0035] In this invention, the first and second matching layers together constitute the matching layer. Throughout the entire fabrication process of the matching layer, the circuit board experiences almost no significant deformation. Therefore, the actual spacing between the circuit board and the mold exhibits excellent consistency with the designed spacing. Since the final actual thickness of the matching layer is determined by the actual spacing between the circuit board and the mold, the designed thickness and actual thickness of the final matching layer can be highly matched. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the exploded structure of a receiving sensor array in the prior art;

[0037] Figure 2 This is a schematic diagram of the three-dimensional structure of a circuit board in the prior art;

[0038] Figure 3 This is a schematic diagram of the three-dimensional structure of the receiving sensor array before the injection of the matching layer slurry in the prior art. Figure 1 ;

[0039] Figure 4 This is a schematic diagram of the three-dimensional structure of the receiving sensor array before the injection of the matching layer slurry in the prior art. Figure 2 ;

[0040] Figure 5 This is a diagram showing the fit between the support frame and the mold in the existing technology;

[0041] Figure 6 This is a schematic diagram of the cross-sectional structure of a receiving sensor array in the prior art;

[0042] Figure 7 This is an enlarged structural diagram of conductive adhesive tape in the prior art;

[0043] Figure 8 This is a schematic diagram of the exploded structure of the receiving sensor array in an embodiment of the present invention;

[0044] Figure 9 This is a schematic cross-sectional view of the receiving sensor array in an embodiment of the present invention;

[0045] Figure 10 for Figure 9 Enlarged structural diagram at point A in the middle;

[0046] Figure 11 This is a schematic diagram of the three-dimensional structure of the conductive adhesive tape after the first matching layer is coated on it in an embodiment of the present invention.

[0047] Figure label:

[0048] 1. Circuit board; 11. Mounting position; 2. Positioning plate; 21. Positioning hole; 3. Receiver array element; 4. Conductive tape; 5. First matching layer; 6. Support frame; 7. Second matching layer; 8. Double-sided adhesive; 81. Clearance hole; 9. Limiting ring; 100. Mold; 200. Encapsulation gap; 201. Encapsulation notch; 300. Matching layer. Detailed Implementation

[0049] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0050] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0055] Existing technology:

[0056] like Figure 1 and Figure 6 As shown, in the prior art, the receiving sensor array includes a circuit board 1, a positioning plate 2, a receiving array element 3, a conductive adhesive tape 4, a matching layer 300, a support frame 6, and a limiting ring 9.

[0057] Circuit board 1, positioning plate 2, and conductive tape 4 are arranged in layers sequentially. A limiting ring 9 is located on the back of circuit board 1, and mounting positions 11 are located on the front of circuit board 1. There is a one-to-one correspondence between mounting positions 11 and receiving array elements 3, with the receiving array elements 3 electrically connected to their respective mounting positions 11. Positioning plates 2 have positioning holes 21, which also correspond one-to-one with receiving array elements 3, with the receiving array elements 3 located within their respective positioning holes 21. The two ends of the positioning holes 21 are respectively shielded by circuit board 1 and conductive tape 4. Circuit board 1 is located in the middle of support frame 6, and the matching layer 300 not only fills the space between support frame 6 and limiting ring 9 but also covers the side of conductive tape 4 facing away from positioning plate 2.

[0058] In the prior art, the fabrication method of the receiving sensor array includes the following steps:

[0059] Step A1: Fix the positioning plate 2 to the front of the circuit board 1, while ensuring that the ends of the mounting position 11 and the positioning hole 21 are aligned. In addition, install the limiting ring 9 on the back of the circuit board 1.

[0060] Step A2: Install the receiving element 3 into the corresponding positioning hole 21, and electrically connect the receiving element 3 to the corresponding mounting position 11.

[0061] Step A3: As Figure 2 As shown, conductive tape 4 is attached to the side of the positioning plate 2 facing away from the circuit board 1, thereby shielding the end of the positioning hole 21.

[0062] Step A4: As Figure 5 As shown, the support frame 6 is supported on the mold 100.

[0063] Step A5: As Figure 3 and Figure 4 As shown, the circuit board 1 is placed in the middle of the support frame 6, and the conductive tape 4 is positioned opposite the mold 100. By supporting the circuit board 1 on the support frame 6, a certain gap and space can be left between the conductive tape 4 and the mold 100.

[0064] Step A6: As Figure 3 and Figure 4 As shown, after the circuit board 1 is supported on the support frame 6, a potting gap 200 is left between a portion of the edge of the circuit board 1 and the inner edge of the support frame 6. In some prior art, the edge of the circuit board 1 is also provided with a potting notch 201, which is connected to the potting gap 200, and the potting gap 200 is connected to the gap between the conductive tape 4 and the mold 100. Matching layer slurry is injected into the space between the support frame 6 and the limiting ring 9 from the back of the circuit board 1. The matching layer slurry flows through the potting notch 201 and the potting gap 200 to the space between the conductive tape 4 and the mold 100 until the space between the support frame 6 and the limiting ring 9 is also filled with matching layer slurry.

[0065] Step A7: Transfer the support frame 6, circuit board 1, and mold 100 together into the vacuum chamber. The mold 100 is supported on the inner bottom wall of the vacuum chamber. Then, evacuate the inside of the vacuum chamber to remove the air between the conductive tape 4 and the mold 100. By evacuating, the matching layer paste can flow better between the conductive tape 4 and the mold 100, and air bubbles inside the matching layer paste can be removed as much as possible. This avoids excessive defects in the matching layer 300 due to air bubbles, which would affect its acoustic performance.

[0066] Step A8: After the matching layer slurry between the support frame 6 and the limiting ring 9 no longer produces obvious bubble bursts, open the vacuum chamber door and remove the support frame 6, circuit board 1, and mold 100 from the vacuum chamber. The matching layer slurry is then allowed to cure naturally or by heating under normal pressure to form the matching layer 300. At this point, the support frame 6 and circuit board 1 can be fixedly connected through the matching layer 300. Finally, the mold 100 and support frame 6 can be separated. During the curing process of the matching layer slurry, the mold 100 prevents leakage of the matching layer slurry and also defines the shape of the final matching layer 300.

[0067] In step A7, the vacuum pump needs to continuously pump air to expel air bubbles from the matching layer slurry. However, due to performance limitations, existing vacuum pumps cannot operate continuously for extended periods. Therefore, at the end of step A7, some unbroken air bubbles will still remain inside the matching layer slurry. Furthermore, because the matching layer slurry is in a vacuum environment, these air bubbles are relatively large.

[0068] The curing time of the matching layer slurry at room temperature is over 72 hours, and at 80℃ it is over 24 hours. Both curing times are much longer than the continuous operating time of the vacuum pump. If the matching layer slurry is cured only in a vacuum environment inside a vacuum chamber, and the vacuum pump is not in operation, the aforementioned large air bubbles will remain inside the matching layer slurry during the curing process, eventually forming large defects inside the matching layer 300, which will seriously affect the acoustic performance of the matching layer 300.

[0069] Therefore, by opening the vacuum chamber door in step A8, the environment of the matching layer slurry is changed from vacuum to atmospheric pressure. This allows atmospheric pressure to compress the residual air bubbles inside the matching layer slurry and reduce their volume. Consequently, the defect volume that these residual air bubbles can form inside the final matching layer 300 will also be reduced, thus minimizing the adverse effects of residual air bubbles on the acoustic performance of the matching layer 300.

[0070] In the existing technology, the actual thickness of the matching layer 300 at the conductive adhesive tape 4 is much smaller than its designed thickness, resulting in a large difference between the actual performance and the designed performance of the receiving sensor array, which cannot meet the actual production and use requirements.

[0071] The inventors discovered through research that the direct cause of the aforementioned technical problem is precisely the action of opening the vacuum chamber door in step A8. Its specific mechanism is as follows.

[0072] After the receiving element 3 is installed into the positioning hole 21, there is a certain gap between the receiving element 3 and the side wall of the positioning hole 21, resulting in air between them. Furthermore, due to the large number of positioning holes 21, a significant amount of air is actually present inside each hole. Figure 7 As shown, the conductive tape 4 has a large number of tiny pores. Therefore, in step A7, as the vacuum pump continuously pumps air, the air inside the positioning hole 21 can leave the positioning hole 21 through the pores in the conductive tape 4. On the other hand, because the pores in the conductive tape 4 are small and the matching layer paste is relatively viscous, the matching layer paste enters the positioning hole 21 very slowly through the pores in the conductive tape 4. For both reasons, at the end of step A7, a certain vacuum space will be formed inside each positioning hole 21.

[0073] Because the matching layer paste has high viscosity and poor fluidity, its pressure transmission effect is also very poor. At the moment the vacuum chamber door is opened in step A8, the back of circuit board 1 changes from a vacuum environment to an atmospheric pressure environment. However, the matching layer paste located on the back of circuit board 1 has difficulty transmitting atmospheric pressure to the front of circuit board 1, resulting in a pressure difference between the front and back of circuit board 1.

[0074] Since the edges of the front side of the circuit board 1 are supported by the support frame 6, the pressure difference between the front and back sides of the circuit board 1 mainly acts on the middle part of the circuit board 1, causing the middle part of the circuit board 1 to deform and bulge towards the mold 100. A key reason why the middle part of the circuit board 1 can bulge and deform towards the mold 100 is that there is a vacuum space inside the positioning hole 21, and the pores in the conductive tape 4 allow the matching layer paste to pass through. The matching layer paste has weak fluidity, and its flow rate is much lower than the deformation rate of the circuit board 1. During the deformation process of the circuit board 1, the matching layer paste can be approximated as not flowing within the mold 100. As the middle part of the circuit board 1 deforms, the conductive tape 4 also moves towards the mold 100 accordingly. During this process, a portion of the matching layer paste between the conductive tape 4 and the mold 100 is transferred through the pores in the conductive tape 4 into the positioning hole 21, thereby reducing the content of the matching layer paste between the conductive tape 4 and the mold 100.

[0075] Due to the material properties of circuit board 1, its deformation is inelastic. Therefore, once circuit board 1 deforms, the space between the conductive adhesive tape 4 and the mold 100 permanently decreases. Furthermore, the matching layer paste, due to its weak fluidity, cannot effectively flow between the conductive adhesive tape 4 and the mold 100 to restore circuit board 1. Under the combined effect of these two factors, the content of the matching layer paste between the conductive adhesive tape 4 and the mold 100 remains low during the curing process, ultimately resulting in insufficient thickness of the matching layer 300 between the conductive adhesive tape 4 and the mold 100.

[0076] Example:

[0077] like Figure 8 , Figure 9 and Figure 10 As shown, the receiving sensor array in this embodiment includes a circuit board 1, double-sided adhesive tape 8, positioning plate 2, receiving array element 3, conductive adhesive tape 4, first matching layer 5, second matching layer 7, support frame 6, and limiting ring 9.

[0078] Circuit board 1, double-sided adhesive tape 8, positioning plate 2, conductive tape 4, and first matching layer 5 are arranged in sequence. A limiting ring 9 is located on the back of circuit board 1, and a mounting position 11 is located on the front of circuit board 1. Circuit board 1 and positioning plate 2 are bonded together by double-sided adhesive tape 8. Alternating holes 81 are etched on double-sided adhesive tape 8, each corresponding to a mounting position 11. Positioning plate 2 has positioning holes 21, each corresponding to an alternating hole 81. Double-sided adhesive tape 8 avoids the end of positioning hole 21 from mounting position 11 through the alternating holes 81. There is a one-to-one correspondence between mounting position 11 and receiving array element 3, and also a one-to-one correspondence between receiving array element 3 and positioning hole 21. Receiving array element 3 is located within the corresponding positioning hole 21, thus electrically connected to the corresponding mounting position 11.

[0079] Optionally, the receiving element 3 is made of piezoelectric ceramic, specifically PZT (lead zirconate titanate) piezoelectric ceramic. This allows the receiving element 3 to have a high voltage constant and a low dielectric loss factor, thereby ensuring that the device has good sensitivity, energy conversion efficiency, and long-term stability under high-frequency operating conditions.

[0080] The acoustic impedance of the positioning plate 2 should be as low as possible compared to the receiving element 3 to avoid acoustic crosstalk. The positioning plate 2 can be made of polymers such as ABS, PVC, and PEEK.

[0081] The two ends of the positioning hole 21 are respectively blocked by the circuit board 1 and the conductive tape 4. The first matching layer 5 covers and blocks the side of the conductive tape 4 that is away from the positioning plate 2. The circuit board 1 is located in the middle of the support frame 6, and the second matching layer 7 not only fills the space between the support frame 6 and the limiting ring 9, but also covers the side of the first matching layer 5 that is away from the conductive tape 4.

[0082] The method for fabricating the receiving sensor array provided in this embodiment includes the following steps:

[0083] Step B1: Etch the clearance holes 81 on the double-sided adhesive 8. The number and position of the clearance holes 81 match the number and position of the mounting positions 11 and the positioning holes 21. Adhere the positioning plate 2 to the front side of the circuit board 1 using the double-sided adhesive 8, so that the ends of the positioning holes 21 are located at the corresponding mounting positions 11.

[0084] Step B2: Apply conductive paste (such as conductive silver paste) to the mounting position 11 through the positioning hole 21 using a dispensing machine or manually. Then, place the receiving element 3 inside the positioning hole 21 and press it to electrically connect it to the mounting position 11 through the conductive paste. The receiving element 3 is in clearance fit with the side wall of the positioning hole 21.

[0085] Step B3: Apply conductive tape 4 to the side of the positioning plate 2 facing away from the circuit board 1, and make the conductive tape 4 cover the end of the positioning hole 21.

[0086] For example, the conductive tape 4 in this embodiment is made of polyester fiber.

[0087] Step B4: Apply a matching layer paste to the side of the conductive tape 4 facing away from the positioning plate 2, and transfer the circuit board 1 into the vacuum chamber. Then turn on the vacuum pump and evacuate the vacuum chamber to remove the air from the positioning hole 21 and the matching layer paste.

[0088] Because the coating thickness of the matching layer paste is very thin, the coating process does not require the mold 100. Furthermore, during the coating process, the conductive tape 4 faces upwards, meaning the conductive tape 4 is positioned above the positioning plate 2.

[0089] Inside the vacuum chamber, the back of circuit board 1 is supported on the inner bottom wall of the chamber. Since the back of circuit board 1 is not completely smooth, there is a certain gap between the back of circuit board 1 and the inner bottom wall of the vacuum chamber. By drawing a vacuum with a vacuum pump, the gap between the back of circuit board 1 and the inner bottom wall of the vacuum chamber, as well as the front of circuit board 1, can simultaneously become a vacuum, thereby maintaining the pressure balance between the front and back of circuit board 1. Thus, the gap between the back of circuit board 1 and the inner bottom wall of the vacuum chamber can be preserved during the vacuuming process.

[0090] Step B5: As Figure 11 As shown, after no obvious air bubbles rupture on the matching layer slurry, the vacuum pump is turned off and the vacuum chamber door is opened. The circuit board 1 is then removed from the vacuum chamber. After the matching layer slurry cures, the first matching layer 5 is formed. The first matching layer 5 covers the conductive tape 4.

[0091] At the instant the vacuum chamber door opens, air rapidly flows to the top of the matching layer paste. Since a vacuum exists inside the positioning hole 21 at this moment, the air above the matching layer paste can force it into the positioning hole 21 through the pores in the conductive tape 4. Simultaneously, air also quickly fills the gap between the back of the circuit board 1 and the inner bottom wall of the vacuum chamber. Thus, at the instant the vacuum chamber door opens, the front and back of the circuit board 1 simultaneously return to atmospheric pressure and achieve pressure equilibrium, preventing deformation of the circuit board 1 at the moment the vacuum chamber door opens.

[0092] Step B6: After the first matching layer 5 is formed, fix the limiting ring 9 on the back of the circuit board 1, then support the support frame 6 on the mold 100, and support the circuit board 1 on the support frame 6.

[0093] By supporting the circuit board 1 on the support frame 6, the first matching layer 5 can be positioned opposite and spaced apart from the mold 100. At the same time, a potting gap 200 is left between the inner edge of the circuit board 1 and the support frame 6.

[0094] Step B7: On the back of the circuit board 1, a matching layer slurry is injected between the support frame 6 and the limiting ring 9. The matching layer slurry flows through the potting gap 200 to the space between the first matching layer 5 and the mold 100 until the space between the support frame 6 and the limiting ring 9 is also filled with the matching layer slurry.

[0095] Step B8: Transfer the mold 100, support frame 6 and circuit board 1 into the vacuum chamber, then evacuate the vacuum chamber and remove the air between the circuit board 1 and the mold 100 by continuously pumping air out of the vacuum pump.

[0096] Step B9: After the matching layer slurry between the support frame 6 and the limiting ring 9 no longer produces obvious bubble bursts, open the vacuum chamber door and remove the support frame 6, circuit board 1, and mold 100 from the vacuum chamber. The matching layer slurry is then allowed to cure naturally or by heating under normal pressure to form the second matching layer 7. Finally, the mold 100 and the support frame 6 can be separated.

[0097] At the moment the vacuum chamber door is opened in step B9, although the back of circuit board 1 returns to atmospheric pressure, creating a pressure difference between the front and back of circuit board 1, the matching layer 5 blocks the matching layer paste, preventing it from entering the positioning hole 21 through the pores in the conductive tape 4. Simultaneously, due to the poor fluidity of the matching layer paste, it cannot flow from between the first matching layer 5 and the mold 100 to between the support frame 6 and the limiting ring 9 in time when the back of circuit board 1 returns to atmospheric pressure. Therefore, at the moment the vacuum chamber door is opened, the matching layer paste between the first matching layer 5 and the mold 100 can provide good support for the front of circuit board 1 through the first matching layer 5, thereby balancing the pressure difference between the front and back of circuit board 1 and effectively limiting the deformation of circuit board 1. Correspondingly, the space between the first matching layer 5 and the mold 100 can be ensured, resulting in good consistency between the designed thickness and the actual thickness of the second matching layer 7.

[0098] In this embodiment, the first matching layer 5 and the second matching layer 7 together constitute the matching layer 300. Since the circuit board 1 undergoes almost no significant deformation during the entire fabrication process of the matching layer 300 in this embodiment, the actual spacing between the circuit board 1 and the mold 100 is highly consistent with the designed spacing. The final actual thickness of the matching layer 300 is determined by the actual spacing between the circuit board 1 and the mold 100, thus the final designed thickness and actual thickness of the matching layer 300 can be highly matched.

[0099] For example, the thickness of the first matching layer 5 is much smaller than the thickness of the second matching layer 7.

[0100] For example, the matching layer slurry in this embodiment is epoxy resin. Specifically, the matching layer slurry in this embodiment is epoxy adhesive F-8216BK from Zhonglan Chenguang Chemical Research and Design Institute Co., Ltd., which requires 72 hours to cure at 45°C.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for fabricating a receiving sensor array, characterized in that, include: A positioning plate (2) with positioning holes (21) is provided on the front side of the circuit board (1); Place the receiving array element (3) inside the positioning hole (21) and electrically connect the receiving array element (3) to the circuit board (1). Conductive tape (4) is provided on the side of the positioning plate (2) away from the circuit board (1), and the conductive tape (4) covers the end of the positioning hole (21). A matching layer paste is applied to the side of the conductive tape (4) facing away from the positioning plate (2), and then the circuit board (1) is transferred into a vacuum chamber and vacuumed to remove the air in the positioning hole (21). The circuit board (1) is taken out of the vacuum chamber and the first matching layer (5) is formed after the matching layer paste is cured. After the first matching layer (5) is formed, the support frame (6) is supported on the mold (100), and the circuit board (1) is supported on the support frame (6). The first matching layer (5) is opposite to the mold (100) and spaced apart. A potting gap (200) is left between the inner edge of the circuit board (1) and the support frame (6). A matching layer slurry is injected into the potting gap (200) on the back side of the circuit board (1) so that the matching layer slurry flows between the circuit board (1) and the mold (100); The mold (100), the support frame (6) and the circuit board (1) are transferred into a vacuum chamber and then a vacuum is drawn to remove the air between the circuit board (1) and the mold (100); The mold (100), the support frame (6) and the circuit board (1) are taken out of the vacuum chamber, and then the matching layer slurry between the circuit board (1) and the mold (100) is cured to form a second matching layer (7). During the process of the matching layer slurry curing to form the second matching layer (7), the first matching layer (5) blocks the matching layer slurry to prevent the matching layer slurry from entering the positioning hole (21) through the conductive tape (4).

2. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The method for preparing the receiving sensor array further includes: Etch clearance holes (81) on double-sided tape (8); The positioning plate (2) is bonded to the front of the circuit board (1) using the double-sided adhesive (8); The double-sided adhesive (8) avoids the end of the positioning hole (21) and the mounting position (11) on the circuit board (1) through the avoidance hole (81). The positioning hole (21) corresponds to the mounting position (11) one by one, and the end of the positioning hole (21) is located at the corresponding mounting position (11). After the positioning plate (2) is bonded to the front of the circuit board (1), conductive paste is applied to the mounting position (11) through the positioning hole (21); After the receiving array element (3) is placed in the positioning hole (21), the receiving array element (3) is pressed so that the receiving array element (3) is electrically connected to the mounting position (11) through conductive paste.

3. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The matching layer slurry is cured by heating.

4. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The matching layer slurry is epoxy resin.

5. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The conductive adhesive tape (4) is made of polyester fiber.

6. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The receiving array element (3) is fitted with the side wall of the positioning hole (21) with a clearance.

7. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The thickness of the first matching layer (5) is less than the thickness of the second matching layer (7).

8. The method for fabricating a receiving sensor array according to claim 1, characterized in that, The receiving array element (3) is made of piezoelectric ceramic.

9. A receiving sensor array, characterized in that, It is prepared by the method for preparing the receiving sensor array as described in any one of claims 1-8.

10. An imaging sonar, characterized in that, It includes a housing, a transmitter, and a receiving sensor array as described in claim 9, wherein the transmitter and the receiving sensor array are mounted on the housing; The transmitter is used to emit sound waves; The receiving sensor array is used to receive sound waves reflected from the imaging target.

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