A method of preparing a receiving sensor array, a receiving sensor array and an imaging sonar

Abstract

The application relates to a receiving sensor array preparation method, a receiving sensor array and an imaging sonar, and comprises the following steps: in the process of curing a matching layer slurry to form the second matching layer, the first matching layer blocks the matching layer slurry to prevent the matching layer slurry from entering the positioning hole by penetrating the conductive adhesive cloth. The first matching layer and the second matching layer jointly constitute a matching layer, and by ensuring the thickness of the second matching layer, the situation that the thickness of the matching layer on the surface of the conductive adhesive cloth is insufficient is effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of imaging sonar, in particular to a preparation method of a receiving sensor array, a receiving sensor array and an imaging sonar. BACKGROUND

[0002] Three-dimensional imaging sonar system is widely used in marine exploration, underwater communication, nondestructive testing and other fields. The most core two components are sound wave transmitter and sound wave receiver. The sound wave transmitter transmits sound waves to the imaging target. The sound waves are reflected by the imaging target and received by the sound wave receiver, and then imaging is performed.

[0003] Among them, the sound wave receiver mainly includes a circuit board, a transducer array arranged on the surface of the circuit board, and a matching layer arranged on the transducer array through a potting process. The matching degree of the structural parameters between the transducer array and the matching layer is crucial to the performance of the sound wave receiver. However, it is found in the actual preparation process of the sound wave receiver that the actual thickness of the matching layer is much smaller than the designed thickness, which causes a large difference between the actual performance of the sound wave receiver and the designed performance, and cannot meet the production requirements. SUMMARY

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

[0005] A preparation method of a receiving sensor array, comprising:

[0006] A positioning plate with a positioning hole is arranged on the front surface of the circuit board;

[0007] The receiving element is placed in the positioning hole, and the receiving element is electrically connected to the circuit board;

[0008] A conductive adhesive tape is arranged on the side of the positioning plate away from the circuit board, and the conductive adhesive tape shields the end of the positioning hole;

[0009] A matching layer slurry is coated on the side of the conductive adhesive tape away from the positioning plate, then the circuit board is transferred into a vacuum box and vacuumized, and then the air in the positioning hole is removed;

[0010] The circuit board is taken out of the vacuum box, and the first matching layer is formed after the matching layer slurry is solidified;

[0011] After the first matching layer is formed, a support frame is supported on a mold, and the circuit board is supported on the support frame, wherein the first matching layer is arranged opposite to and spaced from the mold, and a potting gap is left between the inner edges of the circuit board and the support frame;

[0012] injecting matching layer paste into the back of the circuit board to the gap of the potting, so that the matching layer paste flows to the gap between the circuit board and the mold;

[0013] transferring the mold, the support frame and the circuit board into a vacuum box, and then vacuumizing to remove the air between the circuit board and the mold;

[0014] taking out the mold, the support frame and the circuit board from the vacuum box, and then forming a second matching layer after the matching layer paste between the circuit board and the mold is cured;

[0015] during the process of curing the matching layer paste to form the second matching layer, the first matching layer blocks the matching layer paste from penetrating the conductive adhesive cloth into the positioning hole.

[0016] In one embodiment, the method for preparing the receiving sensor array further comprises:

[0017] etching a relief hole on the double-sided adhesive tape;

[0018] bonding the positioning plate to the front of the circuit board through the double-sided adhesive tape;

[0019] wherein the double-sided adhesive tape avoids the end of the positioning hole and the mounting position on the circuit board through the relief hole, the positioning hole and the mounting position one-to-one correspond, 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, point the conductive paste on the mounting position through the positioning hole;

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

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

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

[0024] In one embodiment, the material of the conductive adhesive cloth is polyester fiber.

[0025] In one embodiment, the receiving element and the side wall of the positioning hole are clearance fit.

[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 material of the receiving element is piezoelectric ceramic.

[0028] A receiving sensor array is obtained by the preparation method of the receiving sensor array.

[0029] An imaging sonar includes a housing, a transmitter and the receiving sensor array, the transmitter and the receiving sensor array are installed on the housing.

[0030] The transmitter is used for transmitting acoustic waves.

[0031] The receiving sensor array is used for receiving acoustic waves reflected by an imaging target.

[0032] The beneficial effects of the present application are:

[0033] During the preparation of the first matching layer, the pressure balance state between the front surface and the back surface of the circuit board is maintained, so that the deformation of the circuit board can be effectively avoided.

[0034] On this basis, during the preparation of the second matching layer, based on the blocking effect of the first matching layer on the matching layer slurry, the matching layer slurry can be effectively prevented from entering the positioning hole. Thus, at the moment of opening the door of the vacuum box, the matching layer slurry can effectively support the circuit board by virtue of its poor flowability, and limit the deformation of the circuit board.

[0035] The first matching layer and the second matching layer of the present application jointly constitute a matching layer. During the entire preparation process of the matching layer of the present application, the circuit board hardly has obvious deformation, so that the actual interval between the circuit board and the mold and the designed interval have good consistency. Since the actual thickness of the matching layer is ultimately determined by the actual interval between the circuit board and the mold, the designed thickness and the actual thickness of the matching layer can be highly matched. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is an exploded structural schematic diagram of the receiving sensor array in the prior art;

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

[0038] Figure 3 It is a three-dimensional structural schematic diagram of the receiving sensor array before pouring the matching layer slurry in the prior art Figure 1 ;

[0039] Figure 4 It is a three-dimensional structural schematic diagram of the receiving sensor array before pouring the matching layer slurry in the prior art Figure 2 ;

[0040] Figure 5 It is a cooperation relationship diagram between the support frame and the mold in the prior art;

[0041] Figure 6 Fig. 2 is a sectional view of the receiving sensor array in the prior art;

[0042] Figure 7 Fig. 3 is an enlarged view of the conductive tape in the prior art;

[0043] Figure 8 Fig. 4 is an exploded view of the receiving sensor array in the embodiment of the present application;

[0044] Figure 9 Fig. 5 is a sectional view of the receiving sensor array in the embodiment of the present application;

[0045] Figure 10 Fig. 6 is an enlarged view of A in Fig. 5; Figure 9

[0046] Figure 11 Fig. 7 is a perspective view of the conductive tape after the first matching layer is coated in the embodiment of the present application.

[0047] Reference signs:

[0048] 1, circuit board; 11, mounting position; 2, positioning plate; 21, positioning hole; 3, receiving element; 4, conductive tape; 5, first matching layer; 6, support frame; 7, second matching layer; 8, double-sided adhesive tape; 81, avoiding hole; 9, limiting ring; 100, mold; 200, pouring gap; 201, pouring gap; 300, matching layer. DETAILED DESCRIPTION

[0049] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many different ways other than those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0050] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0051] ​In addition, the terms "first", "second", etc. are used herein only to describe different instances, and are not used to denote or imply relative importance or a number of indicated technical features. Thus, features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0052] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0053] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0054] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on another element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only embodiment.

[0055] Prior art:

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

[0057] The circuit board 1, the positioning plate 2 and the conductive adhesive tape 4 are sequentially and layerwisely arranged. The limiting ring 9 is arranged on the back surface of the circuit board 1, and the front surface of the circuit board 1 is provided with mounting positions 11. The mounting positions 11 and the receiving elements 3 have a one-to-one correspondence relationship, and the receiving elements 3 are electrically connected at the corresponding mounting positions 11. The positioning plate 2 is provided with positioning holes 21, and the positioning holes 21 and the receiving elements 3 have a one-to-one correspondence relationship, and the receiving elements 3 are located in the corresponding positioning holes 21. The two ends of the positioning holes 21 are respectively shielded by the circuit board 1 and the conductive adhesive tape 4. The circuit board 1 is located in the middle of the support frame 6, and the matching layer 300 not only fills between the support frame 6 and the limiting ring 9, but also covers the side of the conductive adhesive tape 4 away from the positioning plate 2.

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

[0059] Step A1: Fix the positioning plate 2 on the front surface of the circuit board 1, while ensuring that the ends of the mounting positions 11 and the positioning holes 21 are aligned. In addition, the limiting ring 9 is arranged on the back surface of the circuit board 1.

[0060] Step A2: Install the receiving elements 3 into the corresponding positioning holes 21, and electrically connect the receiving elements 3 to the corresponding mounting positions 11.

[0061] Step A3: As shown in Figure 2 , the conductive adhesive tape 4 is pasted to the side of the positioning plate 2 away from the circuit board 1, so that the conductive adhesive tape 4 can shield the ends of the positioning holes 21.

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

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

[0064] Step A6: As shown in Figure 3 and Figure 4 , after the circuit board 1 is supported on the support frame 6, a filling gap 200 is left between part 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 filling notch 201, the filling gap 200 is communicated with the filling notch 201, and the filling gap 200 is communicated to the gap between the conductive adhesive tape 4 and the mold 100. The matching layer paste is poured between the support frame 6 and the limiting ring 9 on the back surface of the circuit board 1, and the matching layer paste flows to the gap between the conductive adhesive tape 4 and the mold 100 through the filling notch 201 and the filling gap 200, until the support frame 6 and the limiting ring 9 are also filled with the matching layer paste.

[0065] Step A7: The support frame 6, the circuit board 1 and the mold 100 are transferred into the vacuum box together, the mold 100 is supported on the inner bottom wall of the vacuum box, and then the inside of the vacuum box is vacuumized, so as to discharge the air between the conductive cloth 4 and the mold 100. By vacuumizing, on the one hand, the matching layer paste can flow better between the conductive cloth 4 and the mold 100, and on the other hand, the air bubbles inside the matching layer paste can be removed as much as possible, so as to avoid too many defects in the matching layer 300 due to air bubbles, thereby affecting the acoustic performance.

[0066] Step A8: After the matching layer paste between the support frame 6 and the limiting ring 9 no longer produces obvious bubble rupture, the door of the vacuum box is opened, and the support frame 6, the circuit board 1 and the mold 100 are taken out of the vacuum box. The matching layer paste is naturally cured or heated and cured in the normal pressure environment, thereby forming the matching layer 300. At this time, the support frame 6 and the circuit board 1 can be fixedly connected through the matching layer 300. Finally, the mold 100 and the support frame 6 are separated. During the curing process of the matching layer paste, the mold 100 prevents the matching layer paste from leaking on the one hand, and limits the shape of the final matching layer 300 on the other hand.

[0067] In step A7, the vacuum pump needs to continuously discharge air in order to continuously discharge the air bubbles inside the matching layer paste. However, due to the performance limitation of the existing vacuum pump, it cannot work continuously for a long time. Therefore, at the end of step A7, there are still some air bubbles in the matching layer paste which have not been broken. Moreover, due to the vacuum environment in which the matching layer paste is located, the volume of the air bubbles is large.

[0068] The curing time of the matching layer paste at room temperature is more than 72h, and the curing time at 80℃ is more than 24h. Both of the curing times are much longer than the continuous working time of the vacuum pump. If the matching layer paste is cured in the vacuum environment of the vacuum box, and the vacuum pump is not in working state, the air bubbles with large volume will remain in the matching layer paste during the curing process, and finally form defects with large volume in the matching layer 300, which seriously affects the acoustic performance of the matching layer 300.

[0069] Therefore, by opening the door of the vacuum box in step A8, the environment of the matching layer paste is changed from vacuum to normal pressure, so that the air bubbles remaining in the matching layer paste can be pressed by the atmospheric pressure and the volume of the air bubbles can be reduced. Correspondingly, the volume of the defects formed by the air bubbles in the matching layer 300 can also be reduced, and the adverse effect of the air bubbles on the acoustic performance of the matching layer 300 is reduced.

[0070] In the prior art, the actual thickness of the matching layer 300 at the conductive adhesive tape 4 is much smaller than the 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 have found that the direct cause of the above technical problems is precisely the opening of the vacuum box door in step A8. The specific mechanism is as follows.

[0072] After the receiving elements 3 are installed into the positioning holes 21, there is a certain gap between the receiving elements 3 and the side walls of the positioning holes 21, and thus there is air between the receiving elements 3 and the side walls of the positioning holes 21. At the same time, since the number of the positioning holes 21 is large, there is actually a large amount of air inside the positioning holes 21. As shown in Figure 7 As shown in the figure, there are a large number of small pores on the conductive adhesive tape 4, so in step A7, as the vacuum pump continuously pumps air, the air in the positioning holes 21 can escape from the positioning holes 21 through the pores on the conductive adhesive tape 4; on the other hand, since the pores on the conductive adhesive tape 4 are small and the matching layer slurry is relatively viscous, the speed of the matching layer slurry entering the positioning holes 21 through the pores on the conductive adhesive tape 4 is very slow. For the above two reasons, at the end of step A7, a certain vacuum space will be formed inside each positioning hole 21.

[0073] Since the matching layer slurry has high viscosity and poor fluidity, it also has poor pressure conduction effect. In the moment when the vacuum box door is opened in step A8, the back surface of the circuit board 1 changes from a vacuum environment to a normal pressure environment, and the matching layer slurry on the back surface of the circuit board 1 is difficult to conduct the atmospheric pressure to the front surface of the circuit board 1, resulting in a pressure difference between the front surface and the back surface of the circuit board 1.

[0074] Since part of the edges of the front surface of the circuit board 1 are supported by the support frame 6, the pressure difference between the front surface and the back surface 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 protrude towards the mold 100. An important reason why the middle part of the circuit board 1 can protrude and deform towards the mold 100 is that there is a vacuum space inside the positioning hole 21, and the pores in the middle of the conductive adhesive tape 4 allow the matching layer slurry to pass through. The matching layer slurry has weak fluidity, and the flow speed of the matching layer slurry is much smaller than the deformation speed of the circuit board 1, and the matching layer slurry can be approximately considered not to flow in the mold 100 during the deformation of the circuit board 1. As the middle part of the circuit board 1 deforms, the conductive adhesive tape 4 will also move towards the mold 100, and in this process, part of the matching layer slurry between the conductive adhesive tape 4 and the mold 100 will transfer to the positioning hole 21 through the pores in the middle of the conductive adhesive tape 4, thereby reducing the amount of matching layer slurry between the conductive adhesive tape 4 and the mold 100.

[0075] Due to the material of the circuit board 1, the deformation of the circuit board 1 is inelastic, so once the circuit board 1 is deformed, the space between the conductive cloth 4 and the mold 100 will be permanently reduced. In addition, due to the weak flowability of the matching layer paste, it cannot effectively flow to the conductive cloth 4 and the mold 100 to restore the circuit board 1. Under the joint action of the two reasons, during the curing process, the matching layer paste content between the conductive cloth 4 and the mold 100 is always in a small state, which finally leads to the insufficient thickness of the matching layer 300 between the conductive cloth 4 and the mold 100.

[0076] Embodiment:

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

[0078] The circuit board 1, the double-sided adhesive 8, the positioning plate 2, the conductive cloth 4 and the first matching layer 5 are sequentially layered. The limiting ring 9 is arranged on the back of the circuit board 1, and the front of the circuit board 1 is provided with a mounting position 11. The circuit board 1 and the positioning plate 2 are bonded by the double-sided adhesive 8. The double-sided adhesive 8 is etched to avoid the hole 81, and the hole 81 and the mounting position 11 are one-to-one corresponding. The positioning plate 2 is provided with a positioning hole 21, and the positioning hole 21 and the hole 81 are one-to-one corresponding. The double-sided adhesive 8 avoids the hole 81 to the end of the positioning hole 21 and the mounting position 11. The mounting position 11 and the receiving array element 3 are in one-to-one correspondence, and the receiving array element 3 and the positioning hole 21 are also in one-to-one correspondence. The receiving array element 3 is located in the corresponding positioning hole 21, and then is electrically connected with the corresponding mounting position 11.

[0079] Optionally, the material of the receiving array element 3 is piezoelectric ceramic, specifically PZT (lead zirconate titanate) piezoelectric ceramic. In this way, the receiving array element 3 has a relatively high high-voltage constant and a relatively low dielectric loss factor, thereby ensuring that the device has good sensitivity, energy conversion efficiency and long-term stability in high-frequency working state.

[0080] The acoustic impedance of the positioning plate 2 should be as low as possible to avoid acoustic crosstalk. The material of the positioning plate 2 can be ABS material, PVC, PEEK and other polymers.

[0081] The two ends of the positioning hole 21 are shielded by the circuit board 1 and the conductive cloth 4. The first matching layer 5 covers and shields the side of the conductive cloth 4 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 between the support frame 6 and the limiting ring 9, but also covers the side of the first matching layer 5 away from the conductive cloth 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] Wherein at the moment when the door of the vacuum box is opened, air will flow rapidly above the matching layer paste, and since there is a vacuum space inside the positioning hole 21 at this time, the air above the matching layer paste can press the matching layer paste into the inside of the positioning hole 21 through the pores on the conductive adhesive tape 4. At the moment when the door of the vacuum box is opened, air will also rapidly fill the gap between the back of the circuit board 1 and the inner bottom wall of the vacuum box. In this way, at the moment when the door of the vacuum box is opened, the front and back of the circuit board 1 can be restored to the atmospheric pressure state at the same time and form a pressure balance, so that deformation of the circuit board 1 can be avoided at the moment when the door of the vacuum box is opened.

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

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

[0094] Step B7: The matching layer paste is injected between the back of the circuit board 1 and the support frame 6 and the limiting ring 9, and the matching layer paste flows to between the first matching layer 5 and the mold 100 through the filling gap 200 until the matching layer paste also fills between the support frame 6 and the limiting ring 9.

[0095] Step B8: The mold 100, the support frame 6 and the circuit board 1 are transferred into the vacuum box, and then vacuumized. Through continuous pumping of the vacuum pump, the air between the circuit board 1 and the mold 100 is removed.

[0096] Step B9: After the matching layer paste between the support frame 6 and the limiting ring 9 no longer produces obvious bubble rupture, the door of the vacuum box is opened, and the support frame 6, the circuit board 1 and the mold 100 are taken out of the vacuum box. The matching layer paste is naturally cured or heated and cured in the normal pressure environment, thereby forming the second matching layer 7. Finally, the mold 100 and the support frame 6 are separated.

[0097] At the moment when the door of the vacuum box is opened in step B9, although the back of the circuit board 1 also returns to atmospheric pressure, a pressure difference is generated between the front and back of the circuit board 1, but because the first matching layer 5 blocks the matching layer paste, the matching layer paste cannot enter the positioning hole 21 through the pores in the conductive adhesive tape 4. At the same time, because the matching layer paste has poor fluidity, at the moment when the back of the circuit board 1 returns to atmospheric pressure, the matching layer paste 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. Therefore, at the moment when the door of the vacuum box is opened, the matching layer paste between the first matching layer 5 and the mold 100 can play a good supporting role on the front of the circuit board 1 through the first matching layer 5, thereby balancing the pressure difference between the front and back of the circuit board 1 and effectively limiting the deformation of the circuit board 1. Correspondingly, the size of the space between the first matching layer 5 and the mold 100 can be ensured, and thus the design thickness and the actual thickness of the second matching layer 7 can be well consistent.

[0098] In the embodiment, the first matching layer 5 and the second matching layer 7 together form the matching layer 300. Because the circuit board 1 has almost no obvious deformation during the entire preparation process of the matching layer 300, the actual interval and the design interval between the circuit board 1 and the mold 100 are well consistent, and the actual thickness of the matching layer 300 is determined by the actual interval between the circuit board 1 and the mold 100. Therefore, the design thickness and the 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 paste in the embodiment is epoxy resin. Specifically, the matching layer paste is epoxy glue F-8216BK of Zhonglan Chen Guang Chemical Research and Design Institute Co., Ltd., and the curing time of the matching layer paste under the condition of 45°C needs 72h.

[0101] The technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.

[0102] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of preparing a receiving sensor array, characterized by, The application relates to a preparation method of a receiving sensor array. A positioning plate (2) with positioning holes (21) is arranged on the front surface of a circuit board (1); A receiving element (3) is arranged in the positioning hole (21) and is electrically connected to the circuit board (1); A conductive adhesive tape (4) is arranged on the back surface of the positioning plate (2) away from the circuit board (1) and covers the end of the positioning hole (21); A matching layer paste is coated on the back surface of the conductive adhesive tape (4) away from the positioning plate (2), then the circuit board (1) is transferred into a vacuum box and vacuumized, and air in the positioning hole (21) is removed; The circuit board (1) is taken out of the vacuum box, and a first matching layer (5) is formed after the matching layer paste is solidified; After the first matching layer (5) is formed, a supporting frame (6) is supported on a mold (100), and the circuit board (1) is supported on the supporting frame (6), wherein the first matching layer (5) is arranged opposite to and spaced from the mold (100), and a pouring gap (200) is left between the inner side edges of the circuit board (1) and the supporting frame (6); The matching layer paste is poured into the pouring gap (200) on the back surface of the circuit board (1), so that the matching layer paste flows between the circuit board (1) and the mold (100); The mold (100), the supporting frame (6) and the circuit board (1) are transferred into a vacuum box, and then vacuumized, so that air between the circuit board (1) and the mold (100) is removed; The mold (100), the supporting frame (6) and the circuit board (1) are taken out of the vacuum box, and a second matching layer (7) is formed after the matching layer paste between the circuit board (1) and the mold (100) is solidified; During the process that the matching layer paste is solidified to form the second matching layer (7), the first matching layer (5) blocks the matching layer paste, so that the matching layer paste cannot enter the positioning hole (21) by penetrating the conductive adhesive tape (4).

2. The preparation method of the receiving sensor array according to claim 1, wherein the preparation method of the receiving sensor array further comprises the following steps: An avoiding hole (81) is etched on a double-sided adhesive tape (8); The positioning plate (2) is adhered to the front surface of the circuit board (1) through the double-sided adhesive tape (8); The double-sided adhesive tape (8) avoids the end of the positioning hole (21) and the mounting position (11) on the circuit board (1) through the avoiding 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 adhered to the front surface of the circuit board (1), conductive paste is dotted on the mounting position (11) through the positioning hole (21); After the receiving element (3) is arranged in the positioning hole (21), the receiving element (3) is pressed, so that the receiving element (3) is electrically connected to the mounting position (11) through the conductive paste. ​ 3. The method of claim 1, wherein the receiving sensing array is prepared by, The matching layer paste is cured by heating.

4. The method of claim 1, wherein the receiving sensing array is prepared by, The matching layer paste is epoxy resin.

5. The method of claim 1, wherein the receiving sensing array is prepared by, The material of the conductive adhesive tape (4) is polyester fiber.

6. The method of claim 1, wherein the receiving sensing array is prepared by, The receiving array element (3) is in clearance fit with the side wall of the positioning hole (21).

7. The method of claim 1, wherein the receiving sensing array is prepared by, The thickness of the first matching layer (5) is less than the thickness of the second matching layer (7).

8. The method of claim 1, wherein the receiving sensing array is prepared by, The material of the receiving array element (3) is piezoelectric ceramic.

9. A receiving sensor array, characterized by Obtained by the preparation method of the receiving sensor array as claimed in any one of claims 1-8.

10. An imaging sonar, characterized by, The receiving sensor array as claimed in claim 9 is installed on the shell. The transmitter is used for transmitting sound waves. The receiving sensor array is used for receiving sound waves reflected by the imaging target.

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