CN115342901B - Piezoelectric device and preparation method thereof - Google Patents

Abstract

The application belongs to the technical field of underwater acoustic measurement and semiconductor devices, and provides a piezoelectric device and a preparation method thereof, wherein the piezoelectric device comprises a first piezoelectric module, a second piezoelectric module and a conductive flat plate; the first piezoelectric module includes a first array with a first substrate, the first array including a plurality of first piezoelectric posts having a first height; the second piezoelectric module includes a second array with a second substrate, the second array including a plurality of second piezoelectric posts having a second height; the electric polarities of the first substrate and the second substrate are the same, and the end faces of the first array and the end faces of the second array are oppositely and fixedly connected to two sides of the conductive flat plate. The piezoelectric device provided by the application adopts the oppositely stacked piezoelectric column array, can comprehensively improve the sensitivity of the piezoelectric device under the condition of keeping the section size of the piezoelectric device unchanged, and is favorable for identifying extremely weak underwater acoustic signals.

Description

A kind of piezoelectric device and its preparation method

technical field

The present application belongs to the technical field of underwater acoustic measurement and semiconductor devices, and specifically provides a piezoelectric device and a preparation method thereof.

Background technique

The underwater acoustic transducer converts the underwater acoustic signal and the electrical signal through the piezoelectric effect, and is a key device in the field of underwater acoustic signal processing. The key to improving the performance of underwater acoustic transducers is to improve the performance of piezoelectric devices (also known as piezoelectric vibrators, sensitive elements) used in them. For example, the performance of underwater acoustic transducers (hydrophones) for medium and high frequency reception The improved research mainly focuses on improving the receiving sensitivity of the transducer, that is, by improving the electromechanical conversion efficiency of the transducer, the receiving sensitivity can be improved, thereby enhancing the ability of the transducer to receive weak signals and increasing the detection range.

约为0.5）将转化为压电小柱阵列的纵向长度伸缩振动（机电耦合系数/>

约为0.7），通过改变材料的振动模态，1-3型压电复合材料等效厚度机电耦合系数会比纯压电材料厚度机电耦合系数提升约20%。然而，上述复合材料由于在压电柱之间填充了柔性聚合物材料，其整体依旧为厚度振动，且上述复合物的使用也增加了损耗。In the prior art, improving the receiving sensitivity of the transducer is mainly achieved by improving the electromechanical conversion efficiency of the transducer. For example, the current common 1-3 piezoelectric composite materials improve the performance by converting the thickness vibration of the whole piezoelectric material into the longitudinal stretching vibration of many piezoelectric small columns, changing the vibration mode of the material. By cutting a single-phase piezoelectric material into an array of piezoelectric pillars, the thickness of the entire piezoelectric material vibrates (electromechanical coupling coefficient

about 0.5) will be transformed into the longitudinal length stretching vibration of the piezoelectric columnar array (electromechanical coupling coefficient />

About 0.7), by changing the vibration mode of the material, the electromechanical coupling coefficient of the equivalent thickness of the 1-3 type piezoelectric composite material will increase by about 20% compared with the pure piezoelectric material thickness electromechanical coupling coefficient. However, the above-mentioned composite material still exhibits thickness vibration as a whole because the flexible polymer material is filled between the piezoelectric columns, and the use of the above-mentioned composite also increases loss.

The above-mentioned existing technical solutions for improving the sensitivity of the transducer still have a lot of room for improvement: on the one hand, it is necessary to conduct in-depth research on the different influences on the electromechanical coupling coefficient caused by the different shapes, sizes, and arrangements of piezoelectric columns. Research and select the best combination of parameters. On the other hand, on the basis of optimizing the piezoelectric columnar array, it is necessary to further improve the overall structure of the piezoelectric device so that it can fully increase the effective electromechanical coupling coefficient. Therefore, a synergistic effect is produced with the optimized piezoelectric small column parameters to further improve the performance of the piezoelectric device.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the purpose of the present application is to provide a piezoelectric device for underwater acoustic transducer with ideal effective electromechanical coupling coefficient and high sensitivity and its preparation method.

The first aspect of the present application provides a piezoelectric device, including a first piezoelectric module, a second piezoelectric module, and a conductive plate; the first piezoelectric module includes a first array with a first substrate, and the first piezoelectric module An array includes a plurality of first piezoelectric pillars having a first height; the second piezoelectric module includes a second array with a second base, the second array includes a plurality of second piezoelectric pillars having a second height; Electric columns; the first base and the second base have the same electrical polarity, and the end faces of the first array and the end faces of the second array are fixedly connected to both sides of the conductive plate facing each other.

Preferably, the cross-section of each of the first piezoelectric columns is a square with a first side length, and the ratio of the first height to the first side length is greater than or equal to 5; each of the second piezoelectric columns The cross section of the column is a square with a second side length, and the ratio of the second height to the second side length is greater than or equal to 5.

Preferably, the ratio of the array period of the first array to the first side length is 1.3-1.5; the ratio of the array period of the second array to the second side length is 1.3-1.5.

Preferably, the first height is equal to the second height and the first array and the second array are mirror-symmetrical with respect to the conductive plate; the thickness of the first base and the thickness of the second base The same and the first substrate and the second substrate are mirror-symmetrical to the conductive plate.

Optionally, piezoelectric materials used in the first piezoelectric module and the second piezoelectric module are piezoelectric ceramics and/or piezoelectric crystals.

The conductive plate is made of a metal plate with a Young's modulus greater than or equal to 9×10^10Pa and a thickness of 0.18mm˜0.3mm.

Preferably, the gaps of the plurality of first piezoelectric columns are filled with air, and the gaps of the plurality of second piezoelectric columns are filled with air.

The second aspect of the present application provides a method for preparing a piezoelectric device, which is used to prepare the above-mentioned piezoelectric device, comprising the following steps:

Determining piezoelectric device parameters that meet the electromechanical coupling performance index, where the piezoelectric device parameters include cross-sectional dimensions of the first piezoelectric column and the second piezoelectric column, the first height and the second height and the periods of the first array and the second array;

cutting the sheet piezoelectric material according to the parameters of the piezoelectric device to form the first piezoelectric module and the second piezoelectric module;

The end faces of the first array and the end faces of the second array are fixed on both sides of the conductive plate facing each other.

The technical solutions provided by the embodiments of the present application have at least the following beneficial effects:

First of all, this application adopts a new type of facing stacked piezoelectric device structure, which can accommodate two parallel piezoelectric modules within the same cross-sectional size as a single piezoelectric module. Using the stacked structure of this piezoelectric module, While keeping the cross-sectional size of the piezoelectric device unchanged, the current value of the electrical signal converted from the acoustic signal can be multiplied, thereby effectively improving the sensitivity of the piezoelectric device and more conducive to the detection of extremely weak water Acoustic signal recognition;

Secondly, the piezoelectric device structure that is stacked in opposite directions and amplifies current in parallel can further improve the effective electromechanical coupling coefficient compared with a single piezoelectric module or multiple piezoelectric module structures in series;

In addition, the piezoelectric device structure proposed in this application extends the longitudinal length of the piezoelectric column as a whole while keeping the transverse dimension of the piezoelectric column unchanged, and the piezoelectric column in a single piezoelectric module does not need to be designed too thin, thus On the basis of improving its longitudinal stretching performance, its ability to resist cracking or breaking is guaranteed, and the overall performance of the piezoelectric device is further improved.

Description of drawings

Figure 1a is a front view of a piezoelectric device according to an embodiment of the present application;

Fig. 1b is a side view of a piezoelectric device according to an embodiment of the present application;

Figure 1c is an exploded view of a piezoelectric device according to an embodiment of the present application;

Fig. 2a is a front view of a first piezoelectric module according to an embodiment of the present application;

Fig. 2b is a top view of a first piezoelectric module according to an embodiment of the present application;

Fig. 2c is a side view of a first piezoelectric module according to an embodiment of the present application;

Figure 3a is a schematic diagram of a piezoelectric cylinder made of pure piezoelectric material;

Fig. 3b is a schematic diagram of a piezoelectric cylinder made of 1-3 type piezoelectric composite materials;

Fig. 3c is a schematic diagram of a piezoelectric column formed of a 1-3-2 type piezoelectric composite material;

Fig. 3d is a schematic diagram of a piezoelectric column composed of 2-1-2 type piezoelectric sensitive materials;

Fig. 3e is a schematic diagram of a piezoelectric column formed of piezoelectric sensitive materials facing a stacked structure;

FIG. 4 shows the longitudinal vibration characteristics of the piezoelectric cylinder in the stacked piezoelectric device structure according to the embodiment of the present application;

5 is a schematic diagram of the main steps of preparing a piezoelectric device according to an embodiment of the present application;

FIG. 6 is an exploded view of an underwater acoustic transducer manufactured using the piezoelectric device of the embodiment of the present application;

FIG. 7a is a physical diagram of the first step of preparing a piezoelectric device according to Example 1 of the present application;

FIG. 7b is a physical diagram of the second step of preparing a piezoelectric device according to Embodiment 1 of the present application;

FIG. 7c is a physical diagram of the third step of preparing a piezoelectric device according to Embodiment 1 of the present application;

Figure 8a is the admittance test results in air of the underwater acoustic transducer manufactured using the piezoelectric device of Example 1 of the present application and the underwater acoustic transducer manufactured using the 2-1-2 piezoelectric sensitive material;

Fig. 8b is the underwater admittance test result of the underwater acoustic transducer manufactured by the piezoelectric device according to Example 1 of the present application and the underwater acoustic transducer manufactured by using the 2-1-2 piezoelectric sensitive material;

FIG. 9 shows the receiving sensitivity test results of the underwater acoustic transducer made of the piezoelectric device according to Example 1 of the present application and the underwater acoustic transducer made of the 2-1-2 piezoelectric sensitive material.

Label in the figure

100: first piezoelectric module, 110: first piezoelectric column, 120: first substrate, 200: second piezoelectric module, 210: second piezoelectric column, 220: second substrate, 300: conductive plate, 400 : sealing layer, 500: shell, 600: metal cover.

Detailed ways

Hereinafter, the present application will be further described based on preferred embodiments with reference to the drawings.

In addition, for the convenience of understanding, various components on the drawings are enlarged or reduced, but this approach is not intended to limit the scope of protection of the present application.

Words in the singular include the plural and vice versa.

In the description of the embodiments of the present application, it should be noted that if the orientation or positional relationship indicated by the terms "upper", "lower", "inner" and "outer" appear, it is based on the orientation or position shown in the drawings relationship, or the usual orientation or positional relationship of the products of the embodiments of the application when used, is only for the convenience of describing the application and simplification of the description, rather than indicating or implying that the referred device or element must have a specific orientation, in order to Specific orientation configurations and operations, therefore, are not to be construed as limitations on the application. In addition, in the description of the present application, in order to distinguish different units, words such as first and second are used in this specification, but these are not limited by the order of manufacture, nor can they be interpreted as indicating or implying relative importance. The titles in the detailed description of the application may be different from those in the claims.

The terms used in this specification are used to describe the embodiments of the present application, but are not intended to limit the present application. It should also be noted that, unless otherwise clearly stipulated and limited, the terms "set", "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral Ground connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediary, or an internal connection between two components. Those skilled in the art can specifically understand the specific meanings of the above terms in this application.

The present application provides a piezoelectric device through an embodiment, the piezoelectric device can have an ideal effective electromechanical coupling coefficient and high receiving sensitivity, can be applied to an underwater acoustic transducer, and realize the connection between an acoustic signal and an electrical signal through the piezoelectric effect convert each other.

Fig. 1a shows a structural front view of a piezoelectric device provided according to some embodiments of the present application, Fig. 1b is a side view of the piezoelectric device, and Fig. 1c is an exploded view of the piezoelectric device. As shown in FIGS. 1 a to 3 c , the piezoelectric device provided by the embodiment of the present application includes a first piezoelectric module 100 , a second piezoelectric module 200 and a conductive plate 300 .

Wherein, the first piezoelectric module 100 includes a first array with a first substrate 120, the first array includes a plurality of first piezoelectric columns 110 with a first height; similarly, the second piezoelectric module 200 includes a A second array of the second substrate 220, the second array includes a plurality of second piezoelectric pillars 210 having a second height.

(即第一阵列的端面处于同一平面)，第一基底120的厚度为/>

。Figures 2a to 2c respectively show the front view, top view and side view of the structure of the first piezoelectric module 100 in some embodiments, as shown in Figure 2a and Figure 2c, the first array of the first piezoelectric module 100 It includes a plurality of first piezoelectric columns 110 periodically arranged on the first substrate 120 along the X and Y directions, wherein each first piezoelectric column 110 has the same height

(that is, the end faces of the first array are in the same plane), the thickness of the first substrate 120 is />

.

，第二基底220的厚度为 />

。The second piezoelectric module 200 has a structure similar to that of the first piezoelectric module 100, and accordingly, each second piezoelectric column 210 has the same height

, the thickness of the second substrate 220 is />

.

的压电陶瓷片或压电晶体片以/>

为切割深度垂直地进行切割制成；同样地，上述第二压电模块200可以通过对经过极化的厚度为/>

的压电陶瓷片或压电晶体片以

为切割深度垂直地进行切割制成；并且，在进行第一压电模块100以及第二压电模块200的切割时，其进刀方向应使得切割后得到的第一压电模块100的第一基底120与第二压电模块200的第二基底220具有同样的电极性。The piezoelectric materials used in the first piezoelectric module 100 and the second piezoelectric module 200 are piezoelectric ceramics or piezoelectric crystals. In the embodiment of the present application, the first piezoelectric module 100 can be polarized The thickness is

Piezoelectric ceramic sheet or piezoelectric crystal sheet with />

Cut vertically for the cutting depth; similarly, the above-mentioned second piezoelectric module 200 can be obtained by having a polarized thickness of

Piezoelectric ceramic sheet or piezoelectric crystal sheet with

It is made by cutting vertically for the cutting depth; and, when cutting the first piezoelectric module 100 and the second piezoelectric module 200, the cutting direction should make the first piezoelectric module 100 of the first piezoelectric module 100 obtained after cutting The substrate 120 has the same electrical polarity as the second substrate 220 of the second piezoelectric module 200 .

In the embodiments provided in Fig. 1a to Fig. 1c and Fig. 2a to Fig. 2c, the cross-sectional shapes of the first substrate 120 and the second substrate 220 are square, in other optional embodiments, those skilled in the art can also according to The design requires modifying the cross-sectional shapes of the first base 120 and the second base 220 , such as adopting a cross-sectional shape such as a rectangle, a circle, a rectangular ring, or a ring.

Returning to Figure 1a to Figure 1c, as shown in Figure 1a to Figure 1c, in the embodiment of the present application, the first piezoelectric module 100 and the second piezoelectric module 200 are fixedly connected through a conductive plate 300, the specific connection method It is: the end faces of the first array and the end faces of the second array are arranged facing each other, and are respectively fixedly connected to the two sides of the conductive plate 300 by means of conductive glue or the like. The first piezoelectric module 100, the conductive plate 300, and the second piezoelectric module 200 that are fixedly connected through the above, the first substrate 120 and the second substrate 220 have the same electrical polarity, the end faces of the first array, the second array The end surface of the conductive plate 300 has the same another electric polarity.

In this embodiment, the above-mentioned first piezoelectric module 100, second piezoelectric module 200, and the conductive plate 300 connecting the two piezoelectric modules form a new type of facing stacked piezoelectric module. The device structure accommodates two parallel piezoelectric modules within the same cross-sectional size as a single piezoelectric module. Using the stacked structure of the piezoelectric module, it is possible to maintain the same cross-sectional size of the piezoelectric device. , the current value of the electrical signal converted from the acoustic signal is multiplied, thereby effectively improving the sensitivity of the piezoelectric device and more conducive to the identification of extremely weak underwater acoustic signals.

In addition, the structure of piezoelectric devices stacked oppositely and amplifying current in parallel can further improve the effective electromechanical coupling coefficient compared with the structure of a single piezoelectric module or a plurality of piezoelectric modules connected in series. The mechanism for improving the effective electromechanical coupling coefficient will be described in detail below.

When measuring or evaluating the performance of the transducer, in addition to characterizing the piezoelectric effect of the piezoelectric material and the energy conversion performance of the reverse piezoelectric effect through the electromechanical coupling coefficient to describe the comprehensive performance of the piezoelectric material, it is also The electromechanical conversion performance of materials can be described intuitively by introducing the effective electromechanical coupling coefficient.

是衡量敏感元件在谐振时转换性能最常用的参数，通常情况下，具有高有效机电耦合系数值的压电器件，其接收灵敏度也比较高。有效机电耦合系数的数值大小不但与振动模态有关，还与材料以及其尺寸参数有关，表征了无损耗、无负载的材料在谐振时存储的能量与存储的全部能量之比，其计算公式如下式所示：Effective Electromechanical Coupling Coefficient

It is the most commonly used parameter to measure the conversion performance of sensitive components at resonance. Usually, piezoelectric devices with high effective electromechanical coupling coefficient values have relatively high receiving sensitivity. The numerical value of the effective electromechanical coupling coefficient is not only related to the vibration mode, but also related to the material and its size parameters, which characterizes the ratio of the energy stored in resonance to the total energy stored in a material without loss and load, and its calculation formula is as follows The formula shows:

为其反谐振频率。In the above formula,

is its anti-resonant frequency.

Based on the analogy principle of electromechanical equivalence, the vibration velocity in an acoustic system can be equivalent to the current in a circuit. Therefore, the greater the current, the greater the vibration velocity at the resonant frequency, that is, the higher the effective electromechanical coupling coefficient and the higher the receiving sensitivity for the same sound pressure.

值得到有效的提升，从而在增大电流以提升压电器件整体灵敏度的基础上，进一步提升其在谐振频率处的声电转换性能，实现了压电器件综合性能指标的优化。The piezoelectric device structure provided by the embodiment of the present application, which is stacked in opposite directions and amplifies current in parallel, can amplify the current of the electrical signal exponentially during the acoustic-electric conversion process, and when other conditions remain unchanged, it can Increase the vibration velocity of the piezoelectric material at the resonant frequency, and thus make the piezoelectric components at the resonant frequency

The value is effectively improved, so that on the basis of increasing the current to improve the overall sensitivity of the piezoelectric device, the acoustic-electric conversion performance at the resonance frequency is further improved, and the optimization of the comprehensive performance index of the piezoelectric device is realized.

In order to verify the effect of the opposing stacking structure proposed in this application on improving the effective electromechanical coupling coefficient, the effective electromechanical coupling coefficients corresponding to different piezoelectric cylinder structures are calculated respectively. Figures 3a to 3e show schematic diagrams of piezoelectric cylinders made of different piezoelectric materials. materials, Figure 3c shows a piezoelectric cylinder made of 1-3-2 piezoelectric composite materials, and Figure 3d shows a piezoelectric cylinder made of 2-1-2 piezoelectric sensitive materials , Fig. 3e is the piezoelectric column formed by the piezoelectric sensitive material of the stacked structure of the present application. In order to maintain the consistency of variables, the lateral dimension of the piezoelectric column in Fig. 3a, the piezoelectric column in Fig. The overall lateral dimension of the structure of the column is consistent with the base lateral dimension of the piezoelectric column in Figure 3d and Figure 3e, and the lateral dimension of the piezoelectric column wrapped with flexible material in Figure 3b and Figure 3c is the same as that of the piezoelectric column in Figure 3d and Figure 3e The lateral dimensions of the body are the same. In the five device structures, metal plates of the same size and thickness are covered. In order to obtain the effective electromechanical coupling coefficients, each structure is simulated, and the effective electromechanical coupling coefficients are calculated and listed in Table 1.

Table 1 Performance comparison of piezoelectric devices with different structures

It can be seen from Table 1 that, under other conditions being the same, the effective electromechanical coupling coefficient of the piezoelectric device structure provided by the embodiment of the present application is the highest, combined with its effect on improving the weak signal recognition ability generated by the amplification of the current, it can Significantly improve the overall performance of the piezoelectric device.

的正方形，并且/>

。类似地，在一些优选的实施例中，每个第二压电柱210的横截面为具有第二边长/>

的正方形，并且/>

。Further, as shown in FIG. 2a to FIG. 2c, in some preferred embodiments of the present application, the cross-section of each first piezoelectric column 110 has a first side length

square of , and />

. Similarly, in some preferred embodiments, the cross-section of each second piezoelectric pillar 210 has a second side length />

square of , and />

.

Studies have shown that by rationally designing the size parameters of the piezoelectric cylinder, the ratio of its longitudinal length to cross-sectional size can be increased as much as possible (that is, the overall structure of the piezoelectric cylinder should be designed as slender as possible. ), which can effectively increase the electromechanical coupling coefficient of its longitudinal stretching vibration mode, thereby improving the receiving sensitivity. However, due to the brittleness of materials such as piezoelectric ceramics or piezoelectric crystals, under the condition of the overall size of the piezoelectric device, such as If the ratio of the longitudinal length of a single piezoelectric module to the cross-sectional size is set too large, the resistance of a single piezoelectric column to lateral force will be insufficient. During the cutting process of piezoelectric materials and the use of piezoelectric devices In the process, cracking and breaking of the piezoelectric cylinder are prone to occur, which affects its longitudinal expansion and contraction performance.

Figure 4 shows the finite element analysis of the longitudinal vibration characteristics of a specific piezoelectric cylinder in the stacked piezoelectric device structure provided by the application. As shown in Figure 4, the piezoelectric device proposed by the application structure, the longitudinal length of the piezoelectric column is extended as a whole under the condition that the transverse dimension of the piezoelectric column remains unchanged, and the piezoelectric column in a single piezoelectric module does not need to be designed too thin, so that on the basis of improving its longitudinal expansion and contraction performance The ability to resist cracking or breaking is guaranteed, and the overall performance of the piezoelectric device is further improved.

，并且/>

。类似地，在一些优选的实施例中，第二阵列中各个第二压电柱210的阵列周期为/>

，并且/>

。Further, as shown in FIG. 2a, in the preferred embodiment above, the array period of each first piezoelectric column 110 in the first array is

, and />

. Similarly, in some preferred embodiments, the array period of each second piezoelectric column 210 in the second array is />

, and />

.

等于/>

，且第一阵列与第二阵列相对于导电平板300镜像对称；以及/>

，且第一基底120与第二基底220相对于导电平板300镜像对称。Further, in some preferred embodiments of the present application, the dimensional parameters of the first piezoelectric module 100 are in exactly the same relationship as the dimensional parameters of the second piezoelectric module 200, namely:

equal to />

, and the first array and the second array are mirror-symmetrical with respect to the conductive plate 300; and/>

, and the first substrate 120 and the second substrate 220 are mirror-symmetrical with respect to the conductive plate 300 .

By arranging the conductive plate 300 between the end faces of the first array and the second array, and arranging the first base 120 and the second base 220, the effect of stress amplification can be achieved to further improve the receiving sensitivity of the transducer. The material of the conductive plate 300 can be gold, silver, copper and other metals with good conductivity. Generally, by reducing the thickness of the conductive plate 300, the impact on the longitudinal stretching vibration of the piezoelectric column caused by its mass can be reduced. , but its thickness is not the thinner the better, this is because: when the thickness of the conductive plate 300 is too thin, due to its insufficient overall rigidity, different regions may undergo different deformations with the longitudinal expansion and contraction of different conductive columns, and then Affect the consistency of the array vibration, therefore, in some preferred embodiments of the present application, the conductive plate 300 is made of a metal (such as yellow Copper), so as to ensure that the conductive plate 300 achieves an ideal balance between mass and rigidity.

As shown in FIG. 1a to FIG. 1c and FIG. 2a to FIG. 2c , in the embodiment of the present application, the gaps between each first piezoelectric column 110 and each second piezoelectric column 210 are filled with air. Usually people are used to prepare 1-3 type and 1-3-2 type piezoelectric composite materials by cutting-fill method. The polymer filled between the piezoelectric columns is generally epoxy resin or silicone rubber. The composite material makes the piezoelectric material change from the overall thickness vibration mode to the longitudinal stretching vibration mode of the piezoelectric small column array, thereby improving the electromechanical coupling coefficient. However, due to the addition of the polymer, the loss is increased and the electromechanical coupling coefficient is reduced. In this application, air is used instead of polymer to fill the gaps of piezoelectric columns, which can fully highlight the longitudinal vibration behavior of piezoelectric columns, so that the thickness vibration of piezoelectric materials can be more reflected in the longitudinal vibration behavior of the array formed by piezoelectric columns, which can maximize Maximize the improvement of electromechanical coupling coefficient.

The present application also provides a method for preparing the above-mentioned piezoelectric device through an embodiment, specifically, the preparation method includes the following steps:

(1) Determine the piezoelectric device parameters that meet the electromechanical coupling performance index, the piezoelectric device parameters include the cross-sectional dimensions of the first piezoelectric column and the second piezoelectric column, the first height and the a second height and a period of the first array and the second array;

(2) cutting the sheet-shaped piezoelectric material according to the parameters of the piezoelectric device to form the first piezoelectric module and the second piezoelectric module;

(3) The end faces of the first array and the end faces of the second array are fixed on both sides of the conductive plate facing each other.

Figure 5 schematically provides an implementation process for further preparation of the piezoelectric device after determining the parameters of the piezoelectric device. Encapsulation is performed through an elastic sealing layer 400 to improve its waterproof and sealing performance.

The exploded view of Fig. 6 further shows the composition structure of the underwater acoustic transducer manufactured using the piezoelectric device of the embodiment of the present application. The underwater acoustic transducer as shown in Figure 6 encapsulates the above-mentioned piezoelectric device (the first piezoelectric module 100, the second piezoelectric module 200 and the conductive plate 300 are prepared according to the above-mentioned preparation method), and the external piezoelectric device is The elastic sealing layer 400 is used for sealing, one of the two electrode leads of the underwater acoustic transducer is connected to the conductive plate, and the other is connected to the first substrate and the second substrate. In addition, there is a waterproof and sound-permeable shell 500 outside the piezoelectric device, and its upper part is sealed by a metal cover 600, thereby completing the manufacture of the underwater acoustic transducer.

Example 1

In this embodiment, the piezoelectric device is prepared according to the above-mentioned method for preparing the piezoelectric device, and the performance of the prepared piezoelectric device applied to the underwater acoustic transducer is tested.

The specific structural parameters of the piezoelectric device are listed in Table 2 below.

Table 2 Structural parameters of piezoelectric devices

1) Preparation process

Specifically, Fig. 7a to Fig. 7c show the preparation process of the piezoelectric device in this embodiment, first take the piezoelectric ceramic block and cut it into an appropriate size with a precision ceramic cutting machine, and further, cut it into a piezoelectric column with a substrate array to form multiple piezoelectric modules with the same shape and structure (as shown in Figure 7a); then apply a thin layer of epoxy to adhere the flat plate of brass material to the piezoelectric post of one of the piezoelectric modules The upper surface of the array and apply high voltage to cure, thus forming a 2-1-2 type piezoelectric sensitive material (as shown in Figure 7b); finally, the upper surface of the piezoelectric column array of another piezoelectric module is mirror-symmetrically bonded Attach to the other side of the plate and apply a high voltage to cure, thereby forming the piezoelectric device of this embodiment (as shown in Figure 7c).

After completing the preparation of the above-mentioned piezoelectric devices, the finished materials can also be sealed and put into self-designed encapsulation molds and poured into the configured polyurethane for high-temperature curing and cooling demoulding to obtain a waterproof seal. piezoelectric devices.

As shown in Figures 7b and 7c, the adhered brass plate needs to be slightly larger than the piezoelectric material to leave a place for the welding lead, and the silver paste can also be used to compensate for the electrodes that are forced to be destroyed due to cutting and other experimental processes.

2) Performance test and comparison

According to the standard test process, the underwater acoustic transducer manufactured by the piezoelectric device of this embodiment and the underwater acoustic transducer manufactured by the 2-1-2 piezoelectric sensitive material shown in Figure 7b were tested in air respectively. Admittance test and underwater performance test, wherein the underwater performance test includes underwater admittance test and receiving sensitivity test.

Fig. 8a shows the air admittance test results of two kinds of underwater acoustic transducers, and Fig. 8b shows the underwater admittance test results of two kinds of underwater acoustic transducers. Figure 9 shows the receiving sensitivity test results of two underwater acoustic transducers. The solid line is the test result of the underwater acoustic transducer manufactured using the piezoelectric device of this embodiment, and the dashed line is the test result of the underwater acoustic transducer manufactured using the 2-1-2 type piezoelectric sensitive material.

According to Figure 8b and Figure 9, the underwater acoustic transducer manufactured using the piezoelectric device of this embodiment and the underwater acoustic transducer manufactured using the 2-1-2 piezoelectric sensitive material have a resonance frequency when working in water Respectively about 118kHz and 228kHz, the receiving sensitivity is respectively -166dB and -180dB, both frequencies are in the high frequency range, and the receiving sensitivity (-166dB) of the underwater acoustic transducer manufactured using the piezoelectric device of this embodiment It is better than the underwater acoustic transducer (-180dB) made of 2-1-2 piezoelectric sensitive material alone, and is far superior to all kinds of curved surface, cylindrical and planar underwater acoustic transducers currently used (receiving sensitivity less than -200dB).

The specific implementation of the application has been described in detail above. For those skilled in the art, without departing from the principle of the application, some improvements and modifications can be made to the application, and these improvements and modifications also belong to the application. The scope of the claims.

Claims (7)

1. A piezoelectric device, characterized in that:

the piezoelectric module comprises a first piezoelectric module, a second piezoelectric module and a conductive flat plate;

the first piezoelectric module includes a first array with a first substrate, the first array including a plurality of first piezoelectric pillars having a first height;

the second piezoelectric module includes a second array with a second substrate, the second array including a plurality of second piezoelectric posts having a second height;

the electric polarities of the first substrate and the second substrate are the same, and the end faces of the first array and the end faces of the second array are oppositely and fixedly connected to two sides of the conductive flat plate;

the gaps of the first piezoelectric columns are filled with air, and the gaps of the second piezoelectric columns are filled with air.

2. A piezoelectric device according to claim 1, wherein:

the cross section of each first piezoelectric column is a square with a first side length, and the ratio of the first height to the first side length is greater than or equal to 5;

the cross section of each second piezoelectric column is a square with a second side length, and the ratio of the second height to the second side length is greater than or equal to 5.

3. A piezoelectric device according to claim 2, wherein:

the ratio of the array period of the first array to the first side length is 1.3-1.5;

the ratio of the array period of the second array to the second side length is 1.3-1.5.

4. A piezoelectric device according to claim 1, wherein:

the first height is equal to the second height and the first array and the second array are mirror symmetric with respect to the conductive plate;

the thickness of the first substrate is the same as that of the second substrate, and the first substrate and the second substrate are in mirror symmetry relative to the conductive flat plate.

5. A piezoelectric device according to claim 1, wherein:

the piezoelectric materials adopted by the first piezoelectric module and the second piezoelectric module are piezoelectric ceramics and/or piezoelectric crystals.

6. A piezoelectric device according to claim 1, wherein:

the conductive flat plate is made of a metal plate with Young modulus more than or equal to 9 multiplied by 10^10Pa and thickness of 0.18 mm-0.3 mm.

7. A method of manufacturing a piezoelectric device, for manufacturing a piezoelectric device according to claim 1, comprising the steps of:

determining piezoelectric device parameters satisfying an electromechanical coupling performance criterion, the piezoelectric device parameters including cross-sectional dimensions of the first and second piezoelectric pillars, the first and second heights, and a period of the first and second arrays;

cutting a sheet-shaped piezoelectric material according to the parameters of the piezoelectric device to form a first piezoelectric module and a second piezoelectric module;

and fixing the end surfaces of the first array and the second array to two surfaces of the conductive flat plate in an opposite mode.

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