Multifunctional tenon-and-mortise-shaped piezoelectric vibrator and preparation method thereof

Abstract

The invention discloses a multifunctional tenon-and-mortise-shaped piezoelectric vibrator and a preparation method thereof, and belongs to the field of piezoelectric materials. A multifunctional tenon-and-mortise-shaped piezoelectric vibrator comprises a tenon-shaped unit, a mortise-shaped unit, a connecting unit and an electrode unit. And the tenon-shaped units are integrally processed. And the mortise-shaped units are integrally processed. And the tenon-shaped units and the mortise-shaped units are laminated and compounded along the thickness direction, so that double-resonant-frequency coupling of a conductance curve is realized, and the purpose of bandwidth expansion is achieved. The tenon-shaped unit and the mortise-shaped unit both comprise air gap modules, and the air gap modules do not contain polymer materials, so that a high electromechanical coupling coefficient can be generated, and the high-sensitivity receiving performance of the transducer is met. The invention further provides a preparation method of the multifunctional tenon-and-mortise-shaped piezoelectric vibrator aiming at the tenon-and-mortise-shaped vibrator structure, the piezoelectric vibrator is integrally formed in a step-by-step cutting-multiple filling mode, the method has the advantages of being simple in process, short in preparation period, low in cost and the like, and development of a high-performance receiving and transmitting small-size integrated underwater acoustic transducer and an array of the high-performance receiving and transmitting small-size integrated underwater acoustic transducer is facilitated.

Description

Technical Field

[0001] The invention relates to a multifunctional mortise and tenon-shaped piezoelectric vibrator and a preparation method thereof, and belongs to the field of piezoelectric materials. Background Art

[0002] The underwater acoustic transducer (transducer) is a device responsible for transmitting and sensing sound signals in the sonar system. It is a sensor that uses sound waves as a carrier to achieve electroacoustic signal conversion. It is currently commonly used in underwater communications, weapon guidance, and ocean detection. According to the difference in working principles, transducers can be divided into piezoelectric, capacitive, inductive, magnetostrictive and other types. Among all types of transducers, piezoelectric transducers are selected for the development of underwater acoustic transducers due to their high stability, low cost, simple preparation process and excellent electroacoustic performance. Since the reception / transmission of the transducer sound waves is achieved through the piezoelectric vibrator inside it in the form of positive / reverse piezoelectric effect, the resonant characteristics, vibration mode, bandwidth and other indicators of the piezoelectric vibrator play a dominant role in the electroacoustic performance of the transducer. Therefore, the development of high-performance piezoelectric vibrators is of great significance to optimize the performance indicators of the transducer.

[0003] The 1-3 type piezoelectric vibrator (1-3 vibrator) is a two-phase piezoelectric vibrator composed of a one-dimensional piezoelectric phase and a three-dimensional polymer phase. It has the advantages of concentrated thickness mode, small acoustic impedance, and high stability. It is a commonly used sensitive element for underwater acoustic transducers. Among them, the piezoelectric phase of the 1-3 vibrator is usually prepared by piezoelectric single crystals and piezoelectric ceramics with high piezoelectric coefficients, so that the vibrator after being composited with the polymer still has high piezoelectricity, which is conducive to the development of transducers with high emission response and high sensitivity reception; the polymer phase is generally prepared by epoxy resin with strong rigidity, and it is embedded in the array of piezoelectric small columns in a three-dimensional mesh structure, which can not only effectively suppress lateral coupling, but also give the piezoelectric vibrator a higher compressive resistance, so that the piezoelectric vibrator can withstand high power and high mechanical strength underwater working environment. However, the 1-3 vibrator still has the following aspects to be improved in the development of transducers: First, the bandwidth is low. The amount of information captured by the transducer in water is closely related to the bandwidth of the piezoelectric vibrator. The higher the bandwidth, the greater the amount of information captured. The bandwidth of traditional 1-3 vibrators is generally around 10kHz, which is difficult to meet the broadband detection requirements of underwater acoustic transducers; second, rigid polymers limit the concentration of thickness modes. Although polymer materials such as epoxy resin can improve the compressive resistance of piezoelectric vibrators, the rigidity of such polymers themselves will bring about lateral coupling, which limits the further improvement of the electromechanical coupling coefficient of the piezoelectric vibrator (limited to around 0.6), thereby affecting the receiving sensitivity characteristics of the transducer; third, the compatibility between broadband transmission and high-sensitivity receiving capabilities is low. At this stage, the most common method to improve the bandwidth of 1-3 vibrators is to use multi-mode vibration coupling to increase the bandwidth. However, the broadband vibrator prepared in this way will cause a low electromechanical coupling coefficient due to the lack of energy concentration, which in turn affects the receiving sensitivity characteristics of the transducer. Therefore, the development of piezoelectric vibrators suitable for broadband transmission (increased bandwidth) and high-sensitivity reception (high electromechanical coupling coefficient) is of great significance to the development of high-performance transceiver transducers. Summary of the invention

[0004] In order to solve the problems of low bandwidth, impure thickness model and low transceiver compatibility of existing 1-3 vibrators, the purpose of the present invention is to provide a multifunctional mortise and tenon piezoelectric vibrator (mortise and tenon vibrator) and its preparation method. The present invention provides a piezoelectric vibrator with a mortise and tenon structure. The mortise unit and the mortise unit are laminated and compounded along the thickness direction to achieve dual resonant frequency coupling of the conductance curve, thereby achieving the purpose of bandwidth expansion. The mortise unit and the mortise unit both contain an air gap module. Since the air gap module does not contain polymer materials, a higher electromechanical coupling coefficient can be generated to meet the high-sensitivity receiving performance of the transducer. In view of the mortise and tenon vibrator structure, the present invention also provides a preparation method for a multifunctional mortise and tenon piezoelectric vibrator. The method adopts a step-by-step cutting-multiple filling method to integrally form a piezoelectric vibrator. It has the advantages of simple process, short preparation cycle, low cost, etc., and has good prospects for the development of high-performance transceiver small-size integrated underwater acoustic transducers and their base arrays.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The invention discloses a multifunctional mortise and tenon piezoelectric vibrator, which comprises a mortise unit, a tenon unit, a connection unit and an electrode unit.

[0007] The tenon unit comprises a rigid tenon module, an air gap module and an electrode unit; the tenon unit is processed in an integrated manner, the height of the middle part matrix is ​​higher than the height of the outer matrix, and the higher part is called a rigid tenon module; the remaining part is called an air gap module; a rigid polymer is filled between the rigid tenon module arrays; the end face of the tenon unit covers the electrode unit; the rigid tenon module is covered with a first top electrode; and the air gap module covers a second top electrode.

[0008] The mortise-shaped units are processed in an integrated manner, the height of the middle part of the matrix is ​​lower than the height of the outer matrix, the recessed part is called a rigid mortise module; the remaining part is called an air gap module; the rigid polymer is filled between the rigid mortise module arrays; the end face of the mortise-shaped unit is covered with the electrode unit; the rigid mortise module is covered with a first top electrode; and the air gap module covers the second top electrode.

[0009] The tenon-shaped unit and the mortise-shaped unit are connected via a connecting unit; after the rigid tenon module and the rigid mortise-shaped module are stacked longitudinally via the connecting unit, multi-mode bandwidth expansion is achieved.

[0010] Preferably, the tenon-shaped unit and the mortise-shaped unit are made of PZT ceramic or PMN-PT single crystal to ensure high-intensity emission and high-sensitivity receiving performance; and the small columns in the array have exactly the same structural parameters.

[0011] Preferably, the rigid polymer material is epoxy resin or PMMA material, which is used to separate the small columns between the piezoelectric arrays and improve the stability and compression resistance of the piezoelectric arrays.

[0012] Preferably, the aspect ratio of the piezoelectric columns in the rigid tenon module and the rigid mortise module is not less than 4:1; the ratio of the width of the piezoelectric column to the array gap width is between 0.24 and 0.35, so as to ensure that the volume fraction of the piezoelectric phase is controlled within the high electromechanical conversion capability range of the material.

[0013] Preferably, the tenon-shaped units and mortise-shaped units are stacked in the thickness direction, wherein the protruding portion of the rigid tenon module should completely fit with the recessed portion of the rigid tenon structure.

[0014] Preferably, the connection unit is made of a decoupling material rubber with a low Young's modulus; the thickness of the connection unit does not exceed 1 mm, and the outer dimensions are adapted to the tenon unit and the mortise unit.

[0015] Preferably, the electrode unit comprises a first top electrode and a second top electrode; the electrode unit is made of a metal material with a thickness not exceeding 0.5 mm.

[0016] A multifunctional mortise and tenon piezoelectric vibrator comprises a rigid tenon module and a rigid mortise eye module as transmitting units of the piezoelectric vibrator, which are used for high mechanical strength broadband transmission of the transducer; an air gap module without rigid polymer is used as a receiving unit of the piezoelectric vibrator, which is used for high-sensitivity reception of the transducer, thereby satisfying the transducer's integrated transmitting and receiving functions.

[0017] The present invention also discloses a method for preparing a multifunctional mortise and tenon-shaped piezoelectric vibrator, which is used to prepare the multifunctional mortise and tenon-shaped piezoelectric vibrator. A method for preparing a multifunctional mortise and tenon-shaped piezoelectric vibrator comprises the following steps:

[0018] S1. Preparation of tenon-shaped units:

[0019] Step 1, preparing a cutting skeleton; cutting the piezoelectric material horizontally and vertically, retaining less than 10% of the piezoelectric material base to form a cutting skeleton;

[0020] Step 2, filling with rigid polymer; filling the rigid polymer glue evenly into the gaps of the cut skeleton, vacuuming to remove bubbles and then curing to form a 1-3-2 rigid piezoelectric composite material;

[0021] Step 3, prepare the tenon structure; use a ruler to measure the position of the rigid tenon module in the 1-3-2 rigid piezoelectric composite material, take an opaque mask to cover the position, and expose the rest of the composite material; fix the sample covered with the mask in the cutting machine again, set the cutting parameters, and make the cutting blade cut off a certain thickness of the remaining material except the mask covered part to form the tenon structure;

[0022] Step 4, preparing an air gap module; removing the mask, washing the composite material with the tenon structure prepared in step 3 with ethanol and fixing it again on the sample stage of the cutting machine, setting the cutting parameters so that the cutting blade cuts off all the rigid polymer parts except the tenon structure along the horizontal and vertical directions to form an air gap module; the tenon-shaped unit at this time has the following characteristics: a raised rigid tenon module in the middle, a uniform piezoelectric column array around, and air filling between the arrays;

[0023] Step 5, coating electrodes: pasting and covering the first top electrode and the second top electrode on the top surface of the rigid tenon module and the top surface of the air gap module respectively;

[0024] S2. Preparation of mortise-shaped unit:

[0025] Step 1, preparing a cutting skeleton; cutting the piezoelectric material horizontally and vertically, retaining less than 10% of the piezoelectric material base to form a cutting skeleton;

[0026] Step 2, filling with rigid polymer; filling the rigid polymer glue evenly into the gaps of the cut skeleton, vacuuming to remove bubbles and then curing to form a 1-3-2 rigid piezoelectric composite material;

[0027] Step 3, prepare the mortise structure; use a ruler to measure the position of the rigid mortise module in the 1-3-2 rigid piezoelectric composite material, take an opaque mask to cover the part other than the rigid mortise module; fix the sample covered with the mask in the cutting machine again, set the cutting parameters, and use the cutting blade to grind the exposed part in the middle of the material to form a mortise structure;

[0028] Step 4, preparing an air gap module; removing the mask, washing the composite material with the mortise structure prepared in step 3 with ethanol and fixing it again on the sample stage of the cutting machine, setting the cutting parameters so that the cutting blade cuts off all the rigid polymer parts except the mortise structure along the horizontal and vertical directions to form an air gap module; the mortise unit at this time has the following characteristics: a concave rigid mortise module in the middle, surrounded by a uniform piezoelectric column array, and air filling between the arrays;

[0029] Step 5, coating electrodes; pasting and covering the first top electrode and the second top electrode on the top surface of the rigid mortise module and the top surface of the air gap module respectively;

[0030] S3. Making a mortise and tenon-shaped piezoelectric vibrator:

[0031] The first connecting unit is fixed between the two first top electrodes of the tenon unit and the mortise unit with adhesive, and the second connecting unit is fixed between the second top electrodes of the tenon unit and the mortise unit with adhesive; thus, a multifunctional tenon-and-mortise piezoelectric vibrator is prepared.

[0032] Beneficial effects:

[0033] 1. The present invention discloses a multifunctional mortise and tenon-shaped piezoelectric vibrator and a preparation method thereof. The mortise and tenon structure can realize longitudinal piezoelectric vibrator stacking, thereby realizing dual-resonance mode coupling, and effectively expanding the frequency bandwidth of traditional piezoelectric vibrators.

[0034] 2. The present invention discloses a multifunctional mortise and tenon-shaped piezoelectric vibrator and a preparation method thereof, which uses rigid polymer and air as fillers of the piezoelectric vibrator respectively, thereby ensuring both the pressure resistance and stability of the central area of ​​the vibrator and the high electromechanical conversion capability of the area surrounding the vibrator, while achieving the dual effects of high-intensity broadband emission and high sensitivity of the transducer.

[0035] 3. The present invention discloses a multifunctional mortise and tenon-shaped piezoelectric vibrator and a preparation method thereof, which adopts a mortise and tenon structure to develop an integrated transceiver transducer, has the characteristics of small size, high integration, and low cost, and is helpful to develop a small integrated transceiver transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the three-dimensional structure of a multifunctional mortise and tenon piezoelectric vibrator.

[0037] Figure 2 It is a schematic diagram of the three-dimensional structure of a multifunctional mortise and tenon piezoelectric vibrator mortise unit.

[0038] Figure 3 It is a schematic diagram of the three-dimensional structure of a rigid tenon module / rigid mortise module of a multifunctional mortise and tenon piezoelectric vibrator.

[0039] Figure 4 The diagram is a planar structural diagram of a multifunctional mortise and tenon piezoelectric vibrator connection unit.

[0040] Figure 5 It is a schematic diagram of the three-dimensional structure of a multifunctional mortise and tenon-shaped piezoelectric vibrator air gap module.

[0041] Figure 6 It is a schematic diagram of the three-dimensional structure of a multifunctional mortise and tenon piezoelectric vibrator mortise unit.

[0042] Figure 7 The present invention is a flow chart for preparing a multifunctional mortise and tenon piezoelectric vibrator.

[0043] Figure 8 This is the simulation result of the conductivity of the emitting part of a multifunctional mortise and tenon piezoelectric vibrator.

[0044] Fig. 9 This is the simulation result of the admittance of the receiving part of a multifunctional mortise and tenon piezoelectric vibrator.

[0045] In the figure, 1 is a tenon unit, 2 is an electrode unit, 3 is a connection unit, 4 is a mortise unit, 5 is a first top electrode, 6 is a second top electrode, 7 is a bottom electrode, 8 is a piezoelectric substrate, 9 is an air gap, 10 is a piezoelectric column, 11 is a rigid polymer, 12 is a first connection unit, and 13 is a second connection unit. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and drawings.

[0047] Figure 1 The schematic diagram of a three-dimensional structure of a multifunctional mortise and tenon piezoelectric vibrator is shown in FIG. The three-dimensional structure of the multifunctional mortise and tenon piezoelectric vibrator is composed of a mortise unit 1, an electrode unit 2, a connection unit 3 and a mortise unit 4, wherein the connection unit 3 is fixed between the electrode units 2 to connect the mortise unit 1 and the mortise unit 4. The electrode unit 2 is fixed to the top surface of the mortise unit 1 and the mortise unit 4 to transmit electrical signals to the piezoelectric material.

[0048] Figure 2 Schematic diagram of the three-dimensional structure of the tenon unit 1. The tenon unit 1 consists of a first top electrode 5, a second top electrode 6, a bottom electrode 7, a piezoelectric substrate 8, an air gap 9, a piezoelectric small column 10 and a rigid polymer 11. The first top electrode 5, the piezoelectric small column 10, the rigid polymer 11, the bottom electrode 7 and the piezoelectric substrate 8 together constitute a rigid tenon module, and its structural schematic diagram is shown in FIG. Figure 3 The piezoelectric pillar 10, the rigid polymer 11 and the piezoelectric substrate 8 form a high-compression-resistant 1-3-2 type composite unit, which can be set as a high-mechanical-strength transmitting unit of the transducer. Figure 4 It is a schematic diagram of the planar structure of the connection unit 3, and the first connection unit 12 and the second connection unit 13 match the rigid tenon module and the air gap module respectively. The first top electrode 5 is fixed to the top surface of the composite composed of the piezoelectric pillar 10 and the rigid polymer 11, and the other end is connected to the first connection unit 12. The first top electrode 5 and the first connection unit 12 have exactly the same planar dimensions; one side of the first top electrode 5 is connected to the first connection unit 12, and the other side is fixed to the top side of the 1-3 composite structure composed of the piezoelectric pillar 10 and the rigid polymer 11. The bottom sides of the piezoelectric pillars 10 and the rigid polymer 11 are connected to the piezoelectric substrate 8 to further improve the material stability. The second top electrode 6, the air gap 9, the piezoelectric pillars 10, the bottom electrode 7 and the piezoelectric substrate 8 together constitute the air gap module. The schematic diagram of the air gap module structure is shown in FIG. Figure 5As shown; one side of the second top electrode 6 is connected to the second connection unit 13, and the other side is fixed to the top side of the 1-3 composite structure composed of the air gap 9 and the piezoelectric pillar 10. The bottom of the air gap 9 and the piezoelectric pillar 10 is connected to the piezoelectric substrate 8 to improve the material stability. The bottom electrode 7 is the original electrode of the piezoelectric material, which is coated on the bottom side of the piezoelectric substrate 8 and has the same function as the electrode unit 2, and is used to conduct the electrical signal generated by the vibrator.

[0049] Figure 6 It is a schematic diagram of the three-dimensional structure of the mortise unit 4, and the connection method of each component is the same as that of the tenon unit 1. In the mortise unit 4, the piezoelectric column 10, the rigid polymer 11, the first top electrode 5, the bottom electrode 7 and the piezoelectric substrate 8 together constitute a rigid mortise module, and the thickness of the rigid mortise module is significantly smaller than the thickness of the air gap module and the rigid tenon module; the air gap module of the mortise unit 4 is also composed of the second top electrode 6, the air gap 9, the piezoelectric column 10, the bottom electrode 7 and the piezoelectric substrate 8, and the structural parameters are the same as those of the air gap module in the tenon unit 1.

[0050] Example 1

[0051] like Figure 1 As shown, a multifunctional mortise and tenon piezoelectric vibrator disclosed in this embodiment includes a tenon unit 1, a mortise unit 4, a connection unit 3 and an electrode unit 2.

[0052] The tenon unit 1 is processed as an integrated whole, the height of the middle part matrix is ​​higher than the height of the outer matrix, and the higher part is called a rigid tenon module; the remaining part is called an air gap module; the rigid polymer 11 is filled between the rigid tenon module arrays; the end face of the tenon unit 1 covers the electrode unit 2; the rigid tenon module is covered with a first top electrode 5; the air gap module covers the second top electrode 6.

[0053] The mortise unit 4 is processed in an integrated manner, the height of the middle part of the matrix is ​​lower than the height of the outer matrix, the recessed part is called a rigid mortise module; the remaining part is called an air gap module; the rigid polymer 11 is filled between the rigid mortise module arrays; the end face of the mortise unit 4 covers the electrode unit 2; the rigid mortise module is covered with a first top electrode 5; the air gap module covers the second top electrode 6.

[0054] The tenon unit 1 and the mortise unit 4 are matched and connected via the connection unit 3; after the rigid tenon module and the rigid mortise module are stacked longitudinally via the connection unit, multi-mode bandwidth expansion is achieved.

[0055] like Figure 3 As shown, the rigid tenon module is composed of a first top electrode 5 , a bottom electrode 7 , a piezoelectric substrate 8 , a piezoelectric column 10 , and a rigid polymer 11 .

[0056] The rigid tenon module and the rigid mortise module are used as the transmitting unit of the piezoelectric vibrator, which is used for high mechanical strength and broadband transmission of the transducer; the air gap module without rigid polymer is used as the receiving unit of the piezoelectric vibrator, which is used for high-sensitivity reception of the transducer, thereby meeting the transducer's integrated transmitting and receiving functions.

[0057] The piezoelectric pillars 10 and the piezoelectric substrate 8 are made of the same material, which is PZT ceramics or PMN-PT single crystal, to ensure high-intensity emission and high-sensitivity receiving performance; the piezoelectric pillars 10 are a uniform periodic array and the pillars in the array have exactly the same structural parameters.

[0058] The piezoelectric pillars 10 are arranged periodically with a height-to-width ratio of not less than 4:1, and all the piezoelectric pillars 10 have complete structural dimensions; in addition, the ratio of the gap to the width of the piezoelectric pillars 10 is between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the range of the material's high electromechanical conversion capability.

[0059] The piezoelectric substrate 8 is used to connect all the piezoelectric columns 10 to further improve the stability and compressive resistance of the rigid tenon module, and the thickness of the piezoelectric substrate 8 is within 10% of the total thickness of the tenon unit 1, which not only greatly weakens the lateral coupling, but also retains the compressive resistance of the vibrator.

[0060] The rigid polymer 11 is made of epoxy resin or PMMA material with relatively high hardness, which is used to separate the piezoelectric columns 10 and improve the stability and pressure resistance of the piezoelectric vibrator.

[0061] The air gap module is composed of a second top electrode 6, a bottom electrode 7, a piezoelectric substrate 8, an air gap 9 and a piezoelectric column 10, wherein the piezoelectric column 10 and the piezoelectric substrate 8 in the air gap module are made of exactly the same material as the first piezoelectric array and piezoelectric substrate corresponding to the rigid tenon module, do not contain the rigid polymer 11, and are thinner than the rigid tenon module.

[0062] The mortise-shaped unit 4 comprises a rigid mortise-shaped module, an air gap module and an electrode unit 2; the mortise-shaped unit 4 is a middle concave structure, and the specific feature is that the thickness of the rigid mortise-shaped module is smaller than that of the air gap module.

[0063] The piezoelectric substrate 8 of the mortise unit 4 and the piezoelectric substrate 8 of the tenon unit 1 are made of exactly the same material and structural parameters. Preferably, the thickness of the piezoelectric substrate of the mortise unit is within 10% of the total thickness of the mortise unit.

[0064] The rigid mortise module is the same as the rigid tenon module, and is composed of a first top electrode 5 , a bottom electrode 7 , a piezoelectric substrate 8 , a piezoelectric column 10 , and a rigid polymer 11 .

[0065] The air gap module of the mortise-shaped unit 4 and the air gap module of the tenon-shaped unit 1 adopt exactly the same configuration, including materials and structure.

[0066] The array structure, scale and structural parameters formed by the piezoelectric columns 10 of the mortise-shaped unit 4 are completely the same as those of the tenon-shaped unit 1 .

[0067] The tenon-shaped units 1 and mortise-shaped units 4 are stacked in the thickness direction, wherein the protruding portion of the rigid tenon module should completely fit with the recessed portion of the rigid tenon structure.

[0068] The connecting unit 3 is divided into a first connecting unit 12 and a second connecting unit 13, and both are made of decoupling material rubber with low Young's modulus, such as cork rubber, silicone rubber, etc.; the first connecting unit 12 is a square solid structure, used to connect the rigid tenon module and the rigid mortise module; the second connecting unit 13 is a hollow square structure, used to connect the tenon unit 1 and the air gap module in the mortise unit 4.

[0069] The thickness of the connecting unit 3 does not exceed 1 mm, and the outer dimensions are adapted to the tenon unit 1 and the mortise unit 4 .

[0070] The electrode unit 2 can be made of metal materials with good conductivity such as silver, copper, platinum, etc., with a thickness not exceeding 0.5 mm; the two-dimensional plane size and structure of the first top electrode 5 and the second top electrode 6 are respectively the same as the first connecting unit 12 and the second connecting unit 13, wherein the top end surfaces of the rigid tenon module and the rigid mortise module are both covered with the first top electrode 5, and the air gap modules of the tenon unit 1 and the mortise unit 4 are both covered with the second top electrode 6.

[0071] A multifunctional mortise and tenon piezoelectric vibrator comprises a rigid tenon module and a rigid mortise eye module as transmitting units of the piezoelectric vibrator, which are used for high mechanical strength broadband transmission of the transducer; an air gap module without rigid polymer is used as a receiving unit of the piezoelectric vibrator, which is used for high-sensitivity reception of the transducer, thereby realizing the integrated transmitting and receiving functions of the transducer.

[0072] Embodiment 2:

[0073] The performance of the piezoelectric vibrator plays a decisive role in the performance of the underwater acoustic transducer. For the development of a transducer with high-intensity broadband transmission and high-sensitivity reception, the piezoelectric vibrator should have a higher bandwidth, a stronger ability to resist external pressure, and a higher electromechanical coupling coefficient. However, the current piezoelectric vibrators (such as piezoelectric ceramics, type 1-3 composite materials, etc.) generally have a narrow bandwidth and a low electromechanical coupling coefficient. Although they have a certain degree of pressure resistance, it is difficult to meet all the above technical requirements. Based on this, the present invention proposes to use a mortise and tenon structure to develop a piezoelectric vibrator with high bandwidth, strong pressure resistance, and high electromechanical coupling coefficient, aiming to solve the problems of the existing technology.

[0074] This embodiment discloses a method for preparing a multifunctional mortise and tenon piezoelectric vibrator, and the specific implementation steps are as follows:

[0075] The first part is a multifunctional mortise and tenon piezoelectric vibrator, the structural parameters of which are designed as follows:

[0076] The general range of underwater high-frequency transducers is generally around 200kHz to 400kHz. From the frequency constant of the PZT-epoxy composite vibrator, which is approximately 1500, it can be seen that the thickness of the piezoelectric vibrator should be in the range of 3.75mm to 7.5mm. In this example, the thickness of the tenon unit 1 is 4.5mm, and the thickness of the mortise unit 4 is 4.2mm. The piezoelectric material is PZT-5A ceramic, which is a dual-purpose transceiver with good hardness, and the rigid polymer is 618 epoxy resin with strong impact resistance. The connection unit 3 is made of silicone rubber material with high decoupling and relatively soft, and the electrode plate is made of copper foil with good conductivity and easy to apply.

[0077] The piezoelectric substrate 8 can bring a certain ability to resist external pressure to the piezoelectric vibrator, so that it can exert better mechanical properties when working. However, if the percentage of the piezoelectric substrate 8 is too high, it will cause strong lateral coupling, thereby greatly reducing the electromechanical coupling coefficient. The present invention designs the ceramic substrates of the tenon unit 1 and the mortise unit 4 to be 0.2 mm, and the thicknesses are 4.4% and 4.8% respectively, both of which do not exceed 10%.

[0078] When the aspect ratio of the piezoelectric material is lower than 3:1, lateral coupling will be induced, resulting in acoustic energy loss. Therefore, the width of the piezoelectric column 10 is set to 1 / 4 of the thickness (4:1), that is, 1 mm. Similarly, in order to obtain a higher electromechanical coupling coefficient, the ratio of the column gap and width of the piezoelectric column 10 of the rigid tenon module should be between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the high electromechanical conversion capability range of the material. Therefore, the slit width is set to 0.3 mm.

[0079] To ensure the uniformity of the piezoelectric vibrator structure, the thickness of the piezoelectric column 10 in the air gap module should be half of that of the rigid tenon module and the rigid mortise structure, that is, 4.15 mm, and the slit width is also set to 0.3 mm.

[0080] Considering that the thickness of the connecting unit 3 does not exceed 1 mm, and the external dimensions are adapted to the tenon unit 1 and the mortise unit 4, the thickness of the silicone rubber gasket is set to 0.5 mm to ensure effective coupling of the mortise and tenon structure; the thickness of the electrode plate should be within 0.5 mm to avoid causing higher resistance, so the copper foil thickness is selected to be set to 0.1 mm.

[0081] The second part is a multifunctional mortise and tenon piezoelectric vibrator, the preparation process is as follows:

[0082] S1. Preparation of tenon unit 1:

[0083] Step 1: Prepare a ceramic cutting skeleton. Take a 105mm×105mm×4.5mm piezoelectric material and fix it on the cutting machine sample stage, set the cutting depth to 4.3mm, the step to 1.3mm, and make the cutting blade cut along the horizontal and vertical directions, leaving 0.2mm of the piezoelectric substrate 8 to form a ceramic cutting skeleton.

[0084] Step 2: Filling with epoxy resin (rigid polymer 11). Prepare a certain amount of epoxy resin glue according to the ratio of epoxy resin: softener: curing agent = 10:1:1, and evenly fill it into the gaps of the cut skeleton. After vacuuming and draining bubbles, solidify and shape it to form a 1-3-2 rigid piezoelectric composite material.

[0085] Step 3: Prepare the tenon structure. Use a ruler to measure the position of the rigid tenon module in the 1-3-2 rigid piezoelectric composite material, take an opaque mask to cover the position, and expose the rest of the composite material; fix the masked sample in the cutting machine again, set the cutting step to 1 / 3 of the blade width, and let the cutting blade grind away 0.15mm thickness to form the tenon structure.

[0086] Step 4: Prepare the air gap module. Remove the mask, wash the composite material with the tenon structure prepared in step 3 with ethanol, and fix it on the cutting machine sample table again. Set the cutting depth to 4.15mm and the step to 1.3mm, so that the cutting blade can cut off the epoxy resin outside the tenon structure horizontally and vertically to form an air gap module. The tenon-shaped unit 1 at this time has the following characteristics: a raised rigid tenon module in the middle, surrounded by an array formed by uniform piezoelectric columns 10, and an air gap 9 between the arrays;

[0087] Step 5: Covering electrodes. Take the customized square copper foil plate (first top electrode 5) and the circular copper foil plate (third top electrode 6), and paste them to cover the top surface of the rigid tenon module and the top surface of the air gap module respectively. At this point, the tenon unit 1 is prepared.

[0088] S2, prepare mortise-shaped unit 4:

[0089] Step 1: Prepare a ceramic cutting skeleton. Take a 105mm×105mm×4.2mm piezoelectric material and fix it on the cutting machine sample stage, set the cutting depth to 4mm, the step to 1.3mm, and make the cutting blade cut along the horizontal and vertical directions, leaving 0.2mm of the piezoelectric substrate 8 to form a ceramic cutting skeleton.

[0090] Step 2: Fill with epoxy resin. Prepare a certain amount of epoxy resin glue according to the ratio of epoxy resin: softener: curing agent = 10:1:1, and evenly fill it into the gaps of the cut skeleton. After vacuuming and draining bubbles, solidify and shape it to make a 1-3-2 rigid piezoelectric composite material.

[0091] Step 3: Prepare the mortise structure. Use a ruler to measure the position of the rigid mortise module in the 1-3-2 rigid piezoelectric composite material, and use an opaque mask to cover the part outside the rigid mortise module; fix the sample covered with the mask in the cutting machine again, set the cutting step to 1 / 3 of the blade width, the cutting depth to 0.15mm, and use the cutting blade to grind the exposed part in the middle of the material to form a mortise structure.

[0092] Step 4: Prepare the air gap module. Remove the mask, wash the composite material with the mortise structure prepared in step 3 with ethanol, and fix it on the cutting machine sample stage again. Set the cutting depth to 4.15mm and the cutting step to 1.3mm, so that the cutting blade can cut off the epoxy resin outside the mortise structure horizontally and vertically to form an air gap module. The mortise unit at this time has the following characteristics: a concave rigid mortise module in the middle, surrounded by an array formed by uniform piezoelectric small columns 10, and an air gap 9 between the arrays;

[0093] Step 5: Coating electrodes. Take the customized square copper foil plate and the circular copper foil plate, and paste them to cover the top surface of the rigid mortise module and the top surface of the air gap module respectively. At this point, the mortise unit 4 is prepared.

[0094] S3. Making a mortise and tenon-shaped piezoelectric vibrator:

[0095] Take a square silicone rubber gasket (first connection unit 12) and a round silicone rubber gasket (second connection unit 13). Use glue to fix the square silicone rubber gasket in the middle of the square copper foil plate of the tenon unit 1 and the mortise unit 4, and use glue to fix the round silicone rubber gasket in the middle of the round copper foil plate of the tenon unit 1 and the mortise unit 4. At this point, a multifunctional tenon-and-mortise piezoelectric vibrator is prepared.

[0096] The performance test of the multifunctional mortise and tenon piezoelectric vibrator prepared in this embodiment is carried out below. In this embodiment, ANSYS 15.0 finite element analysis software is used to simulate the piezoelectric vibrator. Among them, PZT-5A is used as the piezoelectric material in this embodiment, 618 epoxy resin and 704 silicone rubber are rigid polymer and silicone rubber gasket respectively, and the material parameters are shown in the following Table 1:

[0097] Table 1. Material parameters of PZT-5A, epoxy resin and silicone rubber

[0098]

[0099] The mortise and tenon piezoelectric vibrator designed by the present invention comprises a rigid tenon module and a rigid mortise eye module as a transmitting part. In the simulation post-processing module, the conductivity information of the transmitting part of the vibrator is read and plotted as shown in the figure. Figure 8 The conductivity-frequency simulation results shown are for comparison. Figure 8It contains the conductivity information of the tenon-shaped unit and the mortise-shaped unit when driven independently. When two units with similar thickness are stacked longitudinally, two resonant modes can be effectively excited, and these two modes have similar frequency characteristics. After being connected and coupled by a rubber gasket, the waveforms of the two units can be integrated, and the bandwidth can be expanded by approximately one-fold (26kHz), which verifies the rationality of the design idea of ​​the present invention. Table 2 gives the bandwidth comparison results of the tenon-shaped piezoelectric vibrator and the tenon-shaped unit and the mortise-shaped unit driven independently.

[0100] Table 2. Simulation results of the emission part of the mortise and tenon piezoelectric vibrator

[0101]

[0102] The high sensitivity characteristics of the mortise and tenon piezoelectric vibrator are verified below.

[0103] The sensitivity of the piezoelectric vibrator can be evaluated by the electromechanical coupling coefficient. The higher the electromechanical coupling coefficient, the stronger the electromechanical conversion ability of the vibrator, and the stronger the ability of the underwater acoustic transducer to sense weak signals. In the present invention, the air gap module of the piezoelectric vibrator is the receiving part, which drives the receiving part of the tenon unit and the mortise unit of the vibrator, and reads the admittance information in the post-processing to obtain the following: Fig. 9 Table 3 gives the calculated results of the thickness electromechanical coupling coefficient.

[0104] Table 3. Simulation results of the receiving part of the mortise and tenon piezoelectric vibrator

[0105] Resonant frequency Anti-resonance frequency <![CDATA[Electromechanical coupling coefficient k t > 336kHz 436kHz 0.65

[0106] according to Fig. 9 It can be seen that the admittance curve of the air gap module of the mortise and tenon piezoelectric vibrator is smooth and pure, without other significant coupling peaks. Compared with the traditional 1-3 type composite material, the present invention can t The value increased by 8.3%, which proves that the mortise and tenon piezoelectric vibrator has high electromechanical conversion capability, which can give the transducer high sensitivity perception ability. In addition, with the help of the mortise and tenon structure design, the transducer can achieve multi-purpose functions, which not only meets the requirements of high mechanical strength and high broadband transmission capability, but also meets the requirements of high sensitivity receiving perception capability, which has good prospects in the development of new integrated transducers.

[0107] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multifunctional mortise and tenon piezoelectric vibrator, characterized in that: It comprises a tenon unit, a mortise unit, a connection unit and an electrode unit; The tenon unit comprises a rigid tenon module, an air gap module and an electrode unit; the tenon unit is processed in an integrated manner, the height of the middle part matrix is ​​higher than the height of the peripheral matrix, and the higher part is called the rigid tenon module; the remaining part is called the air gap module; the rigid polymer is filled between the rigid tenon module arrays; the end surface of the tenon unit covers the electrode unit; the rigid tenon module covers the first top electrode; the air gap module covers the second top electrode; The mortise-shaped units are processed in an integrated manner, the height of the middle matrix is ​​lower than the height of the peripheral matrix, and the concave part is called a rigid mortise module; The rest is called an air gap module; the rigid polymer is filled between the rigid mortise module arrays; the end surface of the mortise unit covers the electrode unit; the rigid mortise module covers the first top electrode; the air gap module covers the second top electrode; The tenon-shaped unit and the mortise-shaped unit are connected via a connecting unit; after the rigid tenon module and the rigid mortise-shaped module are stacked longitudinally via the connecting unit, multi-mode bandwidth expansion is achieved.

2. A multifunctional mortise and tenon piezoelectric vibrator as claimed in claim 1, characterized in that: The material of the tenon-shaped unit and the mortise-shaped unit is PZT ceramic or PMN-PT single crystal to ensure high-intensity emission and high-sensitivity receiving performance; and the small columns in the array have exactly the same structural parameters.

3. A multifunctional mortise and tenon piezoelectric vibrator as claimed in claim 1, characterized in that: The rigid polymer material is epoxy resin or PMMA material, which is used to separate the small columns between the piezoelectric arrays and improve the stability and pressure resistance of the piezoelectric arrays.

4. A multifunctional mortise and tenon piezoelectric vibrator as claimed in claim 1, characterized in that: The aspect ratio of the piezoelectric columns in the rigid tenon module and the rigid mortise module is not less than 4:1; the ratio of the width of the piezoelectric column to the width of the array gap is between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the high electromechanical conversion capability range of the material.

5. The multifunctional mortise and tenon piezoelectric vibrator according to claim 1, characterized in that: The tenon-shaped units and mortise-shaped units are stacked in the thickness direction, wherein the protruding portion of the rigid tenon module should be completely matched with the recessed portion of the rigid tenon structure.

6. The multifunctional mortise and tenon piezoelectric vibrator according to claim 1, characterized in that: The connection unit is made of a decoupling material rubber with a low Young's modulus; the thickness of the connection unit does not exceed 1 mm, and the outer dimensions are adapted to the tenon unit and the mortise unit.

7. The multifunctional mortise and tenon piezoelectric vibrator according to claim 1, characterized in that: The electrode unit comprises a first top electrode and a second top electrode; the electrode unit is made of metal material with a thickness not exceeding 0.5 mm.

8. A multifunctional mortise and tenon piezoelectric vibrator as claimed in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The rigid tenon module and the rigid mortise module are used as the transmitting unit of the piezoelectric vibrator, which is used for high mechanical strength and broadband transmission of the transducer; the air gap module without rigid polymer is used as the receiving unit of the piezoelectric vibrator, which is used for high-sensitivity reception of the transducer, thereby meeting the transducer's integrated transmitting and receiving functions.

9. A method for preparing a multifunctional mortise and tenon piezoelectric vibrator, used for preparing a multifunctional mortise and tenon piezoelectric vibrator as claimed in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The following steps are included: S1. Preparation of tenon-shaped units: Step 1, preparing a cutting skeleton; cutting the piezoelectric material horizontally and vertically, retaining less than 10% of the piezoelectric material base to form a cutting skeleton; Step 2, filling with rigid polymer; filling the rigid polymer glue evenly into the gaps of the cut skeleton, vacuuming to remove bubbles and then curing to form a 1-3-2 rigid piezoelectric composite material; Step 3, prepare the tenon structure; use a ruler to measure the position of the rigid tenon module in the 1-3-2 rigid piezoelectric composite material, take an opaque mask to cover the position, and expose the rest of the composite material; fix the sample covered with the mask in the cutting machine again, set the cutting parameters, and make the cutting blade cut off a certain thickness of the remaining material except the mask covered part to form the tenon structure; Step 4: preparing an air gap module; Remove the mask, wash the composite material with tenon structure prepared in step 3 with ethanol and fix it on the sample stage of the cutting machine again, set the cutting parameters so that the cutting blade cuts off all the rigid polymer parts except the tenon structure along the horizontal and vertical directions to form an air gap module; the tenon-shaped unit at this time has the following characteristics: a raised rigid tenon module in the middle, surrounded by a uniform piezoelectric column array, and air filling between the arrays; Step 5, coating electrodes: pasting and covering the first top electrode and the second top electrode on the top surface of the rigid tenon module and the top surface of the air gap module respectively; S2. Preparation of mortise-shaped unit: Step 1, preparing a cutting skeleton; cutting the piezoelectric material horizontally and vertically, retaining less than 10% of the piezoelectric material base to form a cutting skeleton; Step 2, filling with rigid polymer; filling the rigid polymer glue evenly into the gaps of the cut skeleton, vacuuming to remove bubbles and then curing to form a 1-3-2 rigid piezoelectric composite material; Step 3, prepare the mortise structure; use a ruler to measure the position of the rigid mortise module in the 1-3-2 rigid piezoelectric composite material, take an opaque mask to cover the part other than the rigid mortise module; fix the sample covered with the mask in the cutting machine again, set the cutting parameters, and use the cutting blade to grind the exposed part in the middle of the material to form a mortise structure; Step 4: preparing an air gap module; Remove the mask, wash the composite material with the mortise structure prepared in step 3 with ethanol and fix it on the sample stage of the cutting machine again, set the cutting parameters so that the cutting blade cuts off all the rigid polymer parts except the mortise structure along the horizontal and vertical directions to form an air gap module; the mortise unit at this time has the following characteristics: a concave rigid mortise module in the middle, surrounded by a uniform piezoelectric column array, and air filling between the arrays; Step 5, coating electrodes; pasting and covering the first top electrode and the second top electrode on the top surface of the rigid mortise module and the top surface of the air gap module respectively; S3. Making a mortise and tenon-shaped piezoelectric vibrator: The first connecting unit is fixed between the two first top electrodes of the tenon unit and the mortise unit with adhesive, and the second connecting unit is fixed between the second top electrodes of the tenon unit and the mortise unit with adhesive; thus, a multifunctional tenon-and-mortise piezoelectric vibrator is prepared.

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