Multifunctional mortise and tenon shaped piezoelectric vibrator and preparation method thereof

Abstract

The application relates to a multifunctional mortise and tenon shaped piezoelectric vibrator and a preparation method thereof, and belongs to the piezoelectric material field. The multifunctional mortise and tenon shaped piezoelectric vibrator comprises a tenon unit, a mortise unit, a connecting unit and an electrode unit. The tenon unit is integrally processed. The mortise unit is integrally processed. The tenon unit and the mortise unit are stacked and combined along the thickness direction, the double resonance frequency coupling of the electric lead curve is realized, the bandwidth expansion purpose is achieved, the tenon unit and the mortise unit both contain air gap modules, the air gap modules do not contain polymer materials, therefore, a higher electromechanical coupling coefficient can be generated to satisfy the high-sensitivity receiving performance of a transducer. The application further provides a preparation method of the multifunctional mortise and tenon shaped piezoelectric vibrator. The method adopts a step-by-step cutting-multiple filling mode to integrally form the piezoelectric vibrator, has the advantages of simple process, short preparation period and low cost, and is helpful to the development of a high-performance receiving and transmitting small-size integrated underwater acoustic transducer and an array thereof.

Description

TECHNICAL FIELD

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

[0002] The underwater acoustic transducer (transducer) is a device responsible for transmitting and sensing acoustic signals in the sonar system, is a kind of sensor that realizes the conversion of electric and acoustic signals by taking acoustic waves as the carrier, and is currently commonly used in underwater communication, weapon guidance and ocean exploration. According to the difference in working principle, the transducer can be divided into piezoelectric, capacitive, inductive, magnetostrictive and other types, and among various types of transducers, the piezoelectric transducer is selected for the development of underwater acoustic transducers due to its high stability, low cost, simple preparation process and excellent electro-acoustic performance. Since the reception / emission of acoustic waves by the transducer is realized through the internal piezoelectric vibrator in the forward / reverse piezoelectric effect mode, the resonance characteristics, vibration mode and frequency bandwidth of the piezoelectric vibrator are the dominant factors affecting the electro-acoustic performance of the transducer, therefore, the development of high-performance piezoelectric vibrator is of great significance for optimizing the performance indicators of the transducer.

[0003] 1-3 piezoelectric vibrator (1-3 vibrator) is a two-phase piezoelectric vibrator composed of one-dimensional piezoelectric phase and three-dimensional polymer phase, which has the advantages of thickness mode concentration, small acoustic impedance and high stability, and is a commonly used sensitive element of underwater acoustic transducer at present. Among them, the piezoelectric phase of 1-3 vibrator is usually prepared by using piezoelectric single crystal and piezoelectric ceramic with high piezoelectric coefficient, so that the vibrator after being compounded with polymer still has high piezoelectricity, which is beneficial to develop transducers with high emission response and high sensitive receiving; the polymer phase is generally prepared by using epoxy resin with strong rigidity, and is embedded in the array of piezoelectric pillars in a three-dimensional network structure, which not only can effectively suppress the transverse coupling, but also can give the piezoelectric vibrator high pressure resistance, so that the piezoelectric vibrator can withstand the underwater working environment with high power and high mechanical strength. However, 1-3 vibrator still needs to be improved in the following aspects in the development of transducers: first, the frequency bandwidth is low. The amount of information captured by the transducer in water is closely related to the frequency bandwidth of the piezoelectric vibrator, the higher the frequency bandwidth, the more information is captured. The bandwidth of the traditional 1-3 vibrator is generally about 10 kHz, which is difficult to meet the wideband detection requirements of underwater acoustic transducer; second, the rigidity of the polymer limits the concentration of the thickness mode. Although the polymer such as epoxy resin can improve the pressure resistance of the piezoelectric vibrator, the rigidity of the polymer itself will cause transverse coupling, which limits the further improvement of the electromechanical coupling coefficient of the piezoelectric vibrator (limited to about 0.6), thereby affecting the receiving sensitivity characteristics of the transducer; third, the compatibility of wideband emission and high sensitive receiving is low. At present, the most commonly used method to improve the bandwidth of 1-3 vibrator is to use multi-mode vibration coupling to improve the bandwidth. However, the wideband vibrator prepared by this method will have low electromechanical coupling coefficient due to energy dispersion, which will affect the receiving sensitivity characteristics of the transducer. Therefore, it is of great significance to develop piezoelectric vibrator suitable for wideband emission (increasing the frequency bandwidth) and high sensitive receiving (high electromechanical coupling coefficient) for developing high-performance transceiver transducers. SUMMARY

[0004] In order to solve the problems of low 1-3 transducer frequency band width, thickness mode impurity and low transceiver compatibility, the present application aims to provide a multifunctional mortise and tenon shaped piezoelectric transducer (mortise and tenon transducer) and a preparation method thereof. The present application provides a piezoelectric transducer with a mortise and tenon structure, the mortise unit and the mortise unit are stacked and combined along the thickness direction to realize the coupling of the double resonance frequency of the electric guide curve and achieve the purpose of bandwidth expansion. The mortise unit and the mortise unit both contain an air gap module, and since the air gap module does not contain polymer material, it can produce a higher electromechanical coupling coefficient to meet the high sensitivity receiving performance of the transducer. The present application also provides a preparation method of a multifunctional mortise and tenon shaped piezoelectric transducer for the mortise and tenon transducer structure, which adopts a step cutting-multiple filling method to integrally form the piezoelectric transducer, has the advantages of simple process, short preparation period and low cost, and has good prospects for developing high-performance transceiving small-size integrated underwater acoustic transducers and their arrays.

[0005] The purpose of the present application is realized by the following technical solutions:

[0006] The multifunctional mortise and tenon shaped piezoelectric transducer disclosed by the present application comprises a mortise unit, a mortise unit, a connecting unit and an electrode unit.

[0007] The mortise unit comprises a rigid tenon module, an air gap module and an electrode unit; the mortise unit is integrally processed, the height of the middle part matrix is higher than the height of the peripheral matrix, and the raised part is called a rigid tenon module; the rest is called an air gap module; the rigid polymer is filled between the rigid tenon module array; the end face of the mortise unit is covered with an electrode unit; the first top electrode is covered on the rigid tenon module; and the second top electrode is covered on the air gap module.

[0008] The mortise unit is integrally processed, the height of the middle part matrix is lower than the height of the peripheral matrix, and the recessed 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 array; the end face of the mortise unit is covered with an electrode unit; the first top electrode is covered on the rigid mortise module; and the second top electrode is covered on the air gap module.

[0009] The mortise unit and the mortise unit are connected through the connecting unit; after the rigid tenon module and the rigid mortise module are stacked along the longitudinal direction through the connecting unit, the multi-mode bandwidth expansion is realized.

[0010] As a preferred, the materials of the mortise unit and the mortise unit are selected from PZT ceramic or PMN-PT single crystal to ensure high strength emission and high sensitivity receiving performance; and the small columns in the array have completely same structure parameters.

[0011] As a preferred, 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 array.

[0012] As preferred, the aspect ratio of the piezoelectric pillars in the rigid tenon module and the rigid mortise module is not less than 4:1; the ratio of the piezoelectric pillar width 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 in the range of high electromechanical conversion capability of the material.

[0013] As preferred, the tenon unit and the mortise unit are stacked in the thickness direction, wherein the protruding part of the rigid tenon module should be completely fitted with the recessed part of the rigid tenon structure.

[0014] As preferred, the connecting unit is made of rubber of low Young's modulus; the thickness of the connecting unit is not more than 1 mm, and the outer dimensions are adapted to the tenon unit and the mortise unit.

[0015] As preferred, the electrode unit includes a first top electrode and a second top electrode; the electrode unit is made of a metal material, and the thickness is not more than 0.5 mm.

[0016] A multifunctional mortise and tenon shaped piezoelectric vibrator, which uses a rigid tenon module and a rigid mortise module as a transmitting unit of a piezoelectric vibrator, is used for high mechanical strength wideband transmission of a transducer; an air gap module without rigid polymer is used as a receiving unit of the piezoelectric vibrator, which is used for high sensitivity receiving of the transducer, and meets the transceiver integrated function of the transducer.

[0017] The application further discloses a preparation method of a multifunctional mortise and tenon shaped piezoelectric vibrator, which is used for preparing the multifunctional mortise and tenon shaped piezoelectric vibrator.

[0018] S1, preparing a tenon unit:

[0019] Step one, preparing a cutting skeleton; the piezoelectric material is cut along the horizontal transverse direction and the longitudinal direction, and the piezoelectric material base within 10% is reserved to form a cutting skeleton;

[0020] Step two, filling a rigid polymer; the rigid polymer glue solution is uniformly filled into the gap of the cutting skeleton, and after vacuumizing and drying bubbles, it is solidified and formed into a 1-3-2 rigid piezoelectric composite material;

[0021] Step three, preparing a tenon structure; the position of the rigid tenon module in the 1-3-2 rigid piezoelectric composite material is measured by a ruler, the position is covered by taking an opaque mask, and the remaining part of the composite material is exposed; the sample covered with the mask is fixed in the cutting machine again, the cutting parameters are set, the cutting blade is used to cut off a certain thickness of the remaining material part except the part covered by the mask, and the tenon structure is formed.

[0022] Step four, preparation of air gap module; remove the mask, and wash the composite material with tenon structure prepared in step three with ethanol, then fix it again on the cutting machine sample table, set the cutting parameters, and cut off all the rigid polymer parts outside the tenon structure along the horizontal and vertical directions to form an air gap module; At this time, the tenon unit has the following characteristics: the middle is a convex rigid tenon module, the surrounding is a uniform piezoelectric column array, and the array is filled with air;

[0023] Step five, cover the electrode; paste the first top electrode and the second top electrode on the top end face of the rigid tenon module and the air gap module respectively;

[0024] S2, preparation of mortise unit:

[0025] Step one, preparation of cutting skeleton; cut the piezoelectric material along the horizontal and vertical directions, leaving 10% or less of the piezoelectric material base to form a cutting skeleton;

[0026] Step two, fill the rigid polymer; uniformly fill the rigid polymer glue into the gap of the cutting skeleton, and after vacuumizing and drying the bubbles, solidify and form a 1-3-2 rigid piezoelectric composite material;

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

[0028] Step four, preparation of air gap module; remove the mask, and wash the composite material with tenon structure prepared in step three with ethanol, then fix it again on the cutting machine sample table, set the cutting parameters, and cut off all the rigid polymer parts outside the tenon structure along the horizontal and vertical directions to form an air gap module; At this time, the tenon unit has the following characteristics: the middle is a convex rigid tenon module, the surrounding is a uniform piezoelectric column array, and the array is filled with air;

[0029] Step five, cover the electrode; paste the first top electrode and the second top electrode on the top end face of the rigid tenon module and the air gap module respectively;

[0030] S3, preparation of tenon and mortise shaped piezoelectric vibrator:

[0031] Fix the first connecting unit with adhesive between the two first top electrodes of the tenon unit and the mortise unit, and fix the second connecting unit with adhesive between the second top electrodes of the tenon unit and the mortise unit; Thus, a multifunctional tenon and mortise shaped piezoelectric vibrator is prepared.

[0032] Advantages:

[0033] 1. The multifunctional mortise and tenon-shaped piezoelectric vibrator and its preparation method, which realizes the longitudinal piezoelectric vibrator lamination by adopting the mortise and tenon structure, and further realizes the double resonance mode coupling, and effectively expands the frequency bandwidth of the traditional piezoelectric vibrator.

[0034] 2. The multifunctional mortise and tenon-shaped piezoelectric vibrator and its preparation method, which respectively takes the rigid polymer and air as the piezoelectric vibrator filler, guarantees the pressure resistance and stability of the vibrator central region, guarantees the high electromechanical conversion capacity of the vibrator surrounding region, and realizes the high-strength wideband emission and high-sensitivity double functions of the transducer.

[0035] 3. The multifunctional mortise and tenon-shaped piezoelectric vibrator and its preparation method, which develops an integrated transceiving transducer by adopting the mortise and tenon structure, has the characteristics of small size, high integration and low cost, and is helpful to develop a small integrated transceiving transducer. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

[0039] Figure 4 It is a plane structure diagram of a connecting unit of a multifunctional mortise and tenon-shaped piezoelectric vibrator.

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

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

[0042] Figure 7 It is a preparation flow chart of a multifunctional mortise and tenon-shaped piezoelectric vibrator.

[0043] Figure 8 It is the simulation result of the electric conductance of the emission part of a multifunctional mortise and tenon-shaped piezoelectric vibrator.

[0044] Figure 9 It is the simulation result of the admittance of the receiving part of a multifunctional mortise and tenon-shaped piezoelectric vibrator.

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

[0046] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with specific examples and drawings.

[0047] Figure 1 It is a schematic diagram of a three-dimensional structure of a multifunctional tenon and mortise piezoelectric vibrator. The three-dimensional structure of the multifunctional tenon and mortise piezoelectric vibrator is composed of a tenon unit 1, an electrode unit 2, a connecting unit 3 and a mortise unit 4, wherein the connecting unit 3 is fixed between the electrode units 2, and serves to connect the tenon unit 1 and the mortise unit 4. The electrode unit 2 is fixed on the top surface of the tenon unit 1 and the mortise unit 4, and is used to transmit an electrical signal to the piezoelectric material.

[0048] Figure 2 It is a schematic diagram of a three-dimensional structure of a tenon unit 1. The tenon unit 1 is composed 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 pillar 10 and a rigid polymer 11. Among them, the first top electrode 5, the piezoelectric pillar 10, the rigid polymer 11, the bottom electrode 7 and the piezoelectric substrate 8 together constitute a rigid tenon module, and a schematic diagram of the structure is shown as Figure 3 The piezoelectric pillar 10, the rigid polymer 11 and the piezoelectric substrate 8 constitute a high-pressure-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 a planar structure of a connecting unit 3, a first connecting unit 12 and a second connecting unit 13 respectively match a rigid tenon module and an air gap module. The first top electrode 5 is fixed on the top surface of the composite composed of the piezoelectric pillar 10 and the rigid polymer 11, and the other end is connected with the first connecting unit 12, and the planar size of the first top electrode 5 and the first connecting unit 12 is completely the same; one side of the first top electrode 5 is connected with the first connecting unit 12, and the other side is fixed on the top side of the 1-3 composite structure composed of the piezoelectric pillar 10 and the rigid polymer 11. The bottom side of the piezoelectric pillar 10 and the rigid polymer 11 is connected with the piezoelectric substrate 8, which is used to further improve the stability of the material. The second top electrode 6, the air gap 9, the piezoelectric pillar 10, the bottom electrode 7 and the piezoelectric substrate 8 together constitute an air gap module, and a schematic diagram of the structure of the air gap module is shown as Figure 5As shown, the second top electrode 6 is connected to the second connecting unit 13 on one side, and fixed to the top side of the 1-3 composite structure composed of the air gap 9 and the piezoelectric pillar 10 on the other side. The bottom of the air gap 9 and the piezoelectric pillar 10 are connected to the piezoelectric substrate 8 to improve material stability. The bottom electrode 7 is the original electrode of the piezoelectric material, covered on the bottom side of the piezoelectric substrate 8, and has the same function as the electrode unit 2, used to conduct the electrical signal generated by the oscillator.

[0049] Figure 6 This is a three-dimensional structural diagram of the mortise unit 4. The connection method of each component is the same as that of the tenon unit 1. In the mortise unit 4, the piezoelectric post 10, the rigid polymer 11, the first top electrode 5, the bottom electrode 7, and the piezoelectric substrate 8 together constitute the rigid mortise module. The thickness of the rigid mortise module is significantly smaller than that 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 post 10, the bottom electrode 7, and the piezoelectric substrate 8. 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, this embodiment discloses a multifunctional tenon-and-mortise piezoelectric vibrator, which includes a tenon unit 1, a mortise unit 4, a connecting unit 3, and an electrode unit 2.

[0052] The tenon unit 1 is integrally processed, with the height of the middle matrix being higher than that of the outer matrix. The higher part is called the rigid tenon module; the remaining part is called the air gap module; the rigid polymer 11 is filled between the rigid tenon module array; the end face of the tenon unit 1 is covered by the electrode unit 2; the rigid tenon module is covered by the first top electrode 5; the air gap module is covered by the second top electrode 6.

[0053] The mortise unit 4 is integrally processed, with the height of the middle matrix being lower than that of the outer matrix. The recessed part is called the rigid mortise module; the remaining part is called the air gap module; the rigid polymer 11 is filled between the rigid mortise module array; the end face of the mortise unit 4 is covered by the electrode unit 2; the rigid mortise module is covered by the first top electrode 5; the air gap module is covered by the second top electrode 6.

[0054] The tenon unit 1 and the mortise unit 4 are matched and connected by the connecting unit 3; the rigid tenon module and the rigid mortise module are stacked longitudinally through the connecting unit to realize multi-mode bandwidth expansion.

[0055] like Figure 3 As shown, the rigid tenon module consists of a first top electrode 5, a bottom electrode 7, a piezoelectric substrate 8, a piezoelectric post 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 the high mechanical strength and wideband 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 the high sensitivity receiving of the transducer, and meets the transceiver integrated function of the transducer.

[0057] The piezoelectric column 10 and the piezoelectric substrate 8 are of the same material, and the material is selected from PZT ceramic or PMN-PT single crystal, so as to ensure the high strength transmission and high sensitivity receiving performance; the piezoelectric column 10 is a uniform periodic array, and the columns in the array have completely same structure parameters.

[0058] The piezoelectric column 10 is arranged periodically, and the aspect ratio is not less than 4:1, and all the piezoelectric columns 10 have completely same structure size; in addition, the ratio of the gap and the width of the piezoelectric column 10 is between 0.24 and 0.35, so as to control the volume fraction of the piezoelectric phase in the material within the high electromechanical conversion capability range of the material.

[0059] The piezoelectric substrate 8 is used for connecting all the piezoelectric columns 10, so as to further improve the stability and pressure resistance of the rigid tenon module; and the thickness of the piezoelectric substrate 8 meets the requirement that the thickness is within 10% of the total thickness of the tenon unit 1, so as to greatly weaken the transverse coupling, and meanwhile, the pressure resistance of the vibrator is reserved.

[0060] The rigid polymer 11 is selected from epoxy resin or PMMA material with high hardness, which is used for separating the piezoelectric column 10, and improving 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; the piezoelectric column 10 and the piezoelectric substrate 8 in the air gap module are made of the same material as the first piezoelectric array and the piezoelectric substrate corresponding to the rigid tenon module, do not contain the rigid polymer 11, and the thickness is less than that of the rigid tenon module.

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

[0063] The piezoelectric substrate 8 of the mortise unit 4 and the piezoelectric substrate 8 in the tenon unit 1 are made of the same material and structure parameters, and preferably, the thickness of the piezoelectric substrate of the mortise unit meets the requirement that the thickness is within 10% of the total thickness of the mortise unit.

[0064] The rigid mortise module is the same as the rigid tenon module, which 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 unit 4 and the air gap module of the tenon unit 1 adopt the same configuration, including materials and structures.

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

[0067] The tenon unit 1 and the mortise unit 4 are stacked along the thickness direction, wherein the protruding part of the rigid tenon module should be completely matched with the recessed part of the rigid mortise 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 low Young's modulus decoupling materials such as rubber, soft rubber, silicone rubber and the like; the first connecting unit 12 is a square solid structure, used for connecting the rigid tenon module and the rigid mortise module; the second connecting unit 13 is a hollow square structure, used for connecting the air gap modules in the tenon unit 1 and the mortise unit 4.

[0069] The thickness of the connecting unit 3 is not more than 1 mm, and the outer dimension is 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 and the like, and the thickness is not more than 0.5 mm; the two-dimensional plane size and structure of the first top electrode 5 and the second top electrode 6 are the same as those of the first connecting unit 12 and the second connecting unit 13, respectively, wherein the top end surface of the rigid tenon module and the rigid mortise module is covered with the first top electrode 5, and the air gap modules of the tenon unit 1 and the mortise unit 4 are covered with the second top electrode 6.

[0071] A multifunctional tenon-mortise-shaped piezoelectric vibrator, which comprises a rigid tenon module and a rigid mortise module as a transmitting unit of a piezoelectric vibrator, used for high mechanical strength wideband emission of a transducer; an air gap module without rigid polymer as a receiving unit of a piezoelectric vibrator, used for high sensitivity reception of a transducer, so as to realize the transceiver integrated function 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, and for the development of a transducer with high strength wideband emission and high sensitivity reception, the piezoelectric vibrator should have a higher frequency bandwidth, a stronger anti-pressure ability and a higher electromechanical coupling coefficient. However, the piezoelectric vibrator (such as piezoelectric ceramic, 1-3 type composite material, etc.) at the present stage generally has a narrow bandwidth and a low electromechanical coupling coefficient, and although it has a certain pressure resistance, it is difficult to meet all the above technical requirements. Based on this, the present application proposes to develop a piezoelectric vibrator with high bandwidth, strong pressure resistance and high electromechanical coupling coefficient by using a tenon-mortise structure, aiming to solve the problems in the prior art.

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

[0075] Part One: A multifunctional tenon-and-mortise piezoelectric vibrator, with the following structural parameters:

[0076] The general range of underwater acoustic high-frequency transducers is around 200kHz to 400kHz. Given that the frequency constant of the PZT-epoxy composite resonator is approximately 1500, the thickness of the piezoelectric resonator should be between 3.75mm and 7.5mm. In this example, the tenon-shaped unit 1 has a thickness of 4.5mm, and the mortise-shaped unit 4 has a thickness of 4.2mm. The piezoelectric material used is PZT-5A ceramic, which is both transceiver and has good hardness. The rigid polymer used is 618 type epoxy resin with high impact resistance. The connecting unit 3 is made of silicone rubber material with high decoupling properties and relatively softness. The electrode plate is made of copper foil with good conductivity and easy application.

[0077] The piezoelectric substrate 8 can provide the piezoelectric vibrator with a certain resistance to external pressure, enabling it to perform well in mechanical operation. However, if the percentage of the piezoelectric substrate 8 is too high, it will lead to strong lateral coupling, thereby significantly reducing the electromechanical coupling coefficient. In this invention, the ceramic substrates of the tenon unit 1 and the mortise unit 4 are both designed to be 0.2 mm thick, accounting for 4.4% and 4.8% of the thickness, respectively, neither exceeding 10%.

[0078] When the aspect ratio of piezoelectric materials is less than 3:1, lateral coupling will occur, resulting in sound energy loss. Therefore, the width of the piezoelectric post 10 is set to 1 / 4 (4:1) of the thickness, i.e., 1 mm. Similarly, in order to obtain a higher electromechanical coupling coefficient, the ratio of the post gap to the width of the piezoelectric post 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 range of high electromechanical conversion capability 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 post 10 in the air gap module should be half that of the rigid tenon module and the rigid mortise structure, i.e., 4.15mm, and the slit width should also be set to 0.3mm.

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

[0081] The second part describes a multifunctional tenon-and-mortise shaped piezoelectric vibrator, the fabrication process of which is as follows:

[0082] S1. Prepare tenon unit 1:

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

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

[0085] Step 3: Prepare the tenon structure. Measure the position of the rigid tenon module on the 1-3-2 rigid piezoelectric composite material using a ruler. Cover this position with an opaque mask, exposing 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 grind off 0.15mm of thickness with the cutting blade to form the tenon structure.

[0086] Step 4: Fabrication of the air gap module. Remove the mask, clean the composite material with the tenon structure prepared in Step 3 with ethanol, and then fix it again onto the sample stage of the cutting machine. Set the cutting depth to 4.15 mm and the step size to 1.3 mm, so that the cutting blade removes the epoxy resin outside the tenon structure along the horizontal and vertical directions, forming the air gap module. At this point, the tenon unit 1 has the following characteristics: a raised, rigid tenon module in the center, surrounded by an array of uniformly distributed piezoelectric pillars 10, with air gaps 9 between the arrays;

[0087] Step 5: Electrode Covering. Take the customized square copper foil plate (first top electrode 5) and the U-shaped copper foil plate (second top electrode 6), and attach 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 complete.

[0088] S2, Preparation of mortise-shaped unit 4:

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

[0090] Step 2: Fill with epoxy resin. Prepare a certain amount of epoxy resin solution according to the ratio of epoxy resin: softener: hardener = 10:1:1. Fill the gaps in the cut skeleton evenly with the epoxy resin solution, remove air bubbles by vacuuming, and then cure to form a 1-3-2 rigid piezoelectric composite material.

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

[0092] Step 4: Fabrication of the air gap module. Remove the mask, wash the composite material with the mortise structure prepared in Step 3 with ethanol, and then fix it again on the cutting machine sample stage. Set the cutting depth to 4.15 mm and the cutting step to 1.3 mm, so that the cutting blade removes the epoxy resin outside the mortise structure along the horizontal and vertical directions to form the air gap module. The mortise-shaped unit at this point has the following characteristics: a concave rigid mortise module in the middle, surrounded by an array of uniformly piezoelectric pillars 10, with air gaps 9 between the arrays;

[0093] Step 5: Electrode Coating. Take the customized square copper foil and the U-shaped copper foil, and attach them to 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 complete.

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

[0095] Take a square silicone rubber washer (first connecting unit 12) and a U-shaped silicone rubber washer (second connecting unit 13). Fix the square silicone rubber washer to the middle of the square copper foil plates of the tenon unit 1 and the mortise unit 4 using adhesive. Fix the U-shaped silicone rubber washer to the middle of the U-shaped copper foil plates of the tenon unit 1 and the mortise unit 4 using adhesive. Thus, a multifunctional tenon-and-mortise piezoelectric vibrator is completed.

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

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

[0098]

[0099] The mortise and tenon piezoelectric vibrator designed in this invention combines a rigid tenon module and a rigid mortise module into the transmitting part. In the simulation post-processing module, the conductivity information of the vibrator's transmitting part is read, and the result is plotted as shown below. Figure 8 The conductivity-frequency simulation results shown are provided for comparison. Figure 8The data includes conductivity information for both tenon and mortise-shaped units when driven independently. When two units of similar thickness are stacked longitudinally, two resonant modes can be effectively excited, and these two modes have similar frequency characteristics. After coupling via a rubber gasket, the waveforms of the two units can be merged, extending the bandwidth by approximately double (26kHz), verifying the rationality of the design concept of this invention. Table 2 shows a comparison of the bandwidth of the tenon-mortise piezoelectric vibrator versus the independently driven tenon and mortise-shaped units.

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

[0101]

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

[0103] The sensitivity of a piezoelectric vibrator can be evaluated by its electromechanical coupling coefficient. A higher electromechanical coupling coefficient indicates a stronger electromechanical conversion capability of the vibrator and a greater ability of the underwater acoustic transducer to sense weak signals. In this invention, the air gap module of the piezoelectric vibrator serves as the receiving part, driving the receiving parts of the vibrator's tenon and mortise units. Admittance information is then read in post-processing to obtain... Figure 9 The admittance-frequency information is shown in Table 3. Table 3 presents the calculation results of the thickness electromechanical coupling coefficient.

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

[0105] Resonance frequency Anti-resonance frequency Electromechanical coupling coefficient k t ]] 336 kHz 436 kHz 0.65

[0106] according to Figure 9 It can be seen that the admittance curve of the air gap module of the tenon-and-mortise piezoelectric vibrator is smooth and pure, without other significant coupling peaks. Compared with traditional type 1-3 composite materials, this invention can reduce k t The 8.3% increase in value confirms that the tenon-and-mortise piezoelectric vibrator possesses high electromechanical conversion capability, which can endow the transducer with high sensitivity. In addition, thanks to the tenon-and-mortise structure design, the transducer can achieve multiple functions in one unit, satisfying both high mechanical strength and wide bandwidth transmission capability, as well as high sensitivity reception capability, showing good prospects in the development of new integrated transducers.

[0107] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description 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 within the scope of protection of the present invention.

Claims

1. A multifunctional tenon-and-mortise piezoelectric vibrator, characterized in that: It includes tenon units, mortise units, connecting units, and electrode units; The tenon unit comprises a rigid tenon module, an air gap module, and an electrode unit; the tenon unit is integrally machined, with the height of the middle matrix being higher than the height of the outer matrix, and the higher part is called the rigid tenon module; the remaining part is called the air gap module; rigid polymer is filled between the rigid tenon module arrays; the end face of the tenon unit covers the electrode unit; a first top electrode is covered on the rigid tenon module; and a second top electrode is covered on the air gap module. The mortise-shaped unit is integrally processed, with the height of the middle matrix being lower than the height of the outer matrix, and the recessed part is called the rigid mortise module; The remaining part is called the air gap module; rigid polymer is filled between the rigid mortise module array; the end face of the mortise unit covers the electrode unit; the first top electrode is covered on the rigid mortise module; the air gap module covers the second top electrode; The tenon unit and the mortise unit are connected by a connecting unit; the rigid tenon module and the rigid mortise module are stacked longitudinally by a connecting unit to achieve multimode bandwidth expansion; The aspect ratio of the piezoelectric post in the rigid tenon module and the rigid mortise module is not less than 4:1; the ratio of the width of the piezoelectric post to the width of the array gap is between 0.24 and 0.35, so as to ensure that the volume fraction of the piezoelectric phase is controlled within the range of high electromechanical conversion capability of the material. The transmitting unit of the piezoelectric vibrator consists of a rigid tenon module and a rigid mortise module, which are used for high mechanical strength broadband transmission of the transducer; the receiving unit of the piezoelectric vibrator consists of an air gap module without rigid polymer, which is used for high sensitivity reception of the transducer, thus satisfying the transducer's integrated transceiver function.

2. The multifunctional tenon-and-mortise piezoelectric vibrator as described in claim 1, characterized in that: The tenon and mortise units are made of PZT ceramic or PMN-PT single crystal to ensure high-intensity emission and high-sensitivity reception performance; and the pillars in the array have exactly the same structural parameters.

3. The multifunctional tenon-and-mortise piezoelectric vibrator as described in claim 1, characterized in that: The rigid polymer material is epoxy resin or PMMA, used to separate the pillars between the piezoelectric arrays while improving the stability and compressive strength of the piezoelectric arrays.

4. A multifunctional tenon-and-mortise piezoelectric vibrator as described in claim 1, characterized in that: The tenon and mortise units are stacked along the thickness direction, wherein the protruding part of the rigid tenon module should completely fit the recessed part of the rigid tenon structure.

5. A multifunctional tenon-and-mortise piezoelectric vibrator as described in claim 1, characterized in that: The connecting unit is made of decoupling material rubber with low Young's modulus; the thickness of the connecting unit does not exceed 1mm, and its external dimensions are adapted to the tenon and mortise units.

6. A multifunctional tenon-and-mortise piezoelectric vibrator as described in claim 1, characterized in that: The electrode unit includes a first top electrode and a second top electrode; the electrode unit is made of metal material and has a thickness of no more than 0.5 mm.

7. A method for preparing a multifunctional tenon-and-mortise piezoelectric vibrator, used to prepare a multifunctional tenon-and-mortise piezoelectric vibrator as described in claims 1, 2, 3, 4, 5 or 6, characterized in that: Includes the following steps, S1. Prepare the tenon unit: Step 1: Prepare the cutting skeleton; cut the piezoelectric material along the horizontal and vertical directions, retaining less than 10% of the piezoelectric material substrate to form the cutting skeleton; Step 2: Filling with rigid polymer; uniformly fill the gaps of the cut skeleton with rigid polymer liquid, remove air bubbles by vacuuming, and then cure 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 this position, exposing 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 remove a certain thickness of the remaining material excluding the mask to form the tenon structure. Step 4: Prepare the air gap module; After removing the mask, the composite material with tenon structure prepared in step three is washed with ethanol and then fixed back onto the sample stage of the cutting machine. The cutting parameters are set so that the cutting blade cuts off all the rigid polymer parts except for the tenon structure in the horizontal and vertical directions to form an air gap module. At this time, the tenon unit has the following characteristics: the middle is a raised rigid tenon module, the surrounding area is a uniform piezoelectric column array, and the space between the arrays is filled with air. Step 5: Electrode Covering; Attach the first and second top electrodes to the top surfaces of the rigid tenon module and the air gap module, respectively. S2. Preparation of mortise-shaped units: Step 1: Prepare the cutting skeleton; cut the piezoelectric material along the horizontal and vertical directions, retaining less than 10% of the piezoelectric material substrate to form the cutting skeleton; Step 2: Filling with rigid polymer; uniformly fill the gaps of the cut skeleton with rigid polymer liquid, remove air bubbles by vacuuming, and then cure 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, 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 parameters, and use the cutting blade to grind the exposed part in the middle of the material to form the mortise structure. Step 4: Prepare the air gap module; After removing the mask, the composite material with the mortise structure prepared in step three is washed with ethanol and then fixed again on the sample stage of the cutting machine. The cutting parameters are set so that the cutting blade cuts off all the rigid polymer parts except for the mortise structure in the horizontal and vertical directions to form an air gap module. At this time, the mortise unit has the following characteristics: the middle is a concave rigid mortise module, the surrounding area is a uniform piezoelectric column array, and the space between the arrays is filled with air. Step 5: Electrode Covering; Attach the first and second top electrodes to the top surfaces of the rigid mortise module and the air gap module, respectively. S3. Fabricating a tenon-and-mortise shaped piezoelectric vibrator: The first connecting unit is fixed with adhesive between the two first top electrodes of the tenon unit and the mortise unit, and the second connecting unit is fixed with adhesive between the second top electrodes of the tenon unit and the mortise unit; thus, a multifunctional tenon-mortise piezoelectric vibrator is prepared.

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