Electrode structure of piezoelectric sensor

Abstract

The utility model discloses an electrode structure of a piezoelectric sensor, which belongs to the technical field of piezoelectric sensors and comprises micro piezoelectric units distributed in an array, and a plurality of adhesive fibers consistent with the longitudinal length of the array are arranged at transverse intervals of the micro piezoelectric units. A plurality of positive conductive metal sheets and negative conductive metal sheets which are alternately arranged in a positive-negative mode are arranged at longitudinal intervals of the micro-piezoelectric units, a reinforcing frame is arranged on the outer side of the micro-piezoelectric units distributed in an array mode, a positive electrode assembly and a negative electrode assembly adhere to the two sides of the upper surface of the reinforcing frame respectively, and the positive electrode assembly and the negative electrode assembly are formed by arranging silver wires. During assembly, the flexible characteristic of the silver wires is utilized, the effect of connection between the positive conductive metal sheet and the negative conductive metal sheet is improved, assembly is simple, and the problem of electrical conduction of a positive bus circuit, a negative bus circuit and a conductive circuit in structure is solved. The upper surface protection film and the lower surface protection film are adhered to the upper side and the lower side of the micro-piezoelectric unit and the reinforcing frame respectively; the service life is prolonged.

Description

Technical Field

[0001] This utility model relates to a piezoelectric sensor, specifically an electrode structure for a piezoelectric sensor, and belongs to the field of piezoelectric sensor technology. Background Technology

[0002] Piezoelectric ceramics, as a special type of functional material, can sense external stress fields through the direct piezoelectric effect and release stress waves through the inverse piezoelectric effect. Because ordinary piezoelectric materials are hard and brittle, they are not suitable for curved structures. Therefore, some scholars and researchers at home and abroad have miniaturized piezoelectric materials and used flexible materials as a framework to assemble piezoelectric composite materials suitable for curved structures. Piezoelectric composite materials can be named according to the connectivity of each phase. Two-phase piezoelectric composite materials have 10 types of connectivity, while three-phase piezoelectric composite materials have 20 types. Representative two-phase piezoelectric composite materials include 0-3, 2-2, and 1-3 types. The commercially available MFC (Macrofibercomposites) belongs to the 1-3 type. This piezoelectric composite material is encapsulated by bonding piezoelectric fibers with flexible interdigitated positive and negative electrodes on the upper and lower surfaces. Utilizing the special positive and negative electric fields formed by the interdigitated electrodes, the piezoelectric fibers are polarized into highly efficient functional materials with d33 characteristics and opposite polarization directions, thus effectively utilizing the longitudinal strain performance of the piezoelectric fibers and giving MFC high-efficiency output characteristics.

[0003] However, due to the high precision required in the manufacturing of piezoelectric sensors, there are often discrepancies in the fit between the electrode assembly and the etching tank during installation, resulting in a lower yield rate. This makes it impossible to align the electrodes during installation, leading to lower installation efficiency and an increase in defective products. Utility Model Content

[0004] The purpose of this invention is to provide an electrode structure for a piezoelectric sensor to solve the above problems, which can improve the yield rate, facilitate the installation of the positive / negative electrode assembly inside the etching tank, and connect it with the internal positive and negative conductive metal sheets, thereby reducing production difficulty and the number of defective products.

[0005] This utility model achieves the above-mentioned objective through the following technical solution: an electrode structure for a piezoelectric sensor, comprising an array of micro piezoelectric units, wherein multiple adhesive fibers of the same longitudinal length as the array are arranged between the lateral spacing of the micro piezoelectric units, and multiple alternating positive and negative conductive metal sheets are arranged between the longitudinal spacing of the micro piezoelectric units. A reinforcing frame is arranged on the outer side of the array of micro piezoelectric units, and a positive electrode assembly and a negative electrode assembly are respectively adhered to both sides of the upper surface of the reinforcing frame. The positive electrode assembly is connected to the multiple positive conductive metal sheets. The negative electrode assembly is connected to multiple negative conductive metal sheets, and the positive electrode assembly and the negative electrode assembly are composed of silver wires. The micro piezoelectric unit and the upper and lower sides of the reinforcing frame are respectively covered with an upper surface protective film and a lower surface protective film. By bonding fibers, positive conductive metal sheets and negative conductive metal sheets, the arrayed micro piezoelectric units are formed into a whole and fixed by the reinforcing frame. This not only improves the problem of uneven internal electric field, but also overcomes the problem of easy material detachment during the grinding process, which facilitates the preparation.

[0006] Preferably, the upper and lower protective films are polyimide insulating coatings, the micro piezoelectric unit is a piezoelectric ceramic material with high d and g values, and its polarization direction is from the positive conductive metal sheet to the negative conductive metal sheet.

[0007] Preferably, the positive conductive metal sheet and the negative conductive metal sheet are made of highly conductive copper or silver. The positive conductive metal sheet and the negative conductive metal sheet are bonded to the micro piezoelectric unit by conductive silver paste. The adhesive fibers that isolate the positive conductive metal sheets break down, allowing charge movement. A path is formed between the positive conductive metal sheets located in the same column. Similarly, the adhesive fibers that isolate the negative conductive metal sheets break down, allowing charge movement. A path is formed between the negative conductive metal sheets located in the same column.

[0008] Preferably, the adhesive fiber is made of flexible epoxy resin, and the adhesive fiber is seamlessly bonded to the contact surface of the micro piezoelectric unit, allowing for charge movement without resistance. The reinforcing frame is made of flexible epoxy resin, and the contact surfaces of the positive electrode assembly, the reinforcing frame, and the adhesive fiber are completely bonded, with insulation and no charge movement between them. Similarly, the contact surfaces of the negative electrode assembly, the reinforcing frame, and the adhesive fiber are completely bonded, with insulation and no charge movement between them.

[0009] Preferably, positive electrode etching grooves and negative electrode etching grooves are etched on both sides of the reinforcing frame, respectively. The positive electrode assembly is bonded to the inside of the positive electrode etching groove, and the negative electrode assembly is bonded to the inside of the negative electrode etching groove. This facilitates wiring of the positive electrode assembly and the negative electrode assembly, making the fabrication easier. It solves the problem that when the positive electrode assembly or negative electrode assembly is fabricated by current sputtering and other processes and then embedded in the etching groove, it cannot be aligned, resulting in poor or no connection between the surface electrode and the embedded electrode, leading to a low yield.

[0010] Preferably, a positive rectangular pad is arranged at the end of the positive electrode etching tank, and the end of the positive electrode assembly is welded to the positive rectangular pad. A negative rectangular pad is arranged at the end of the negative electrode etching tank, and the end of the negative electrode assembly is welded to the negative rectangular pad. This facilitates connection with external circuits through the positive and negative rectangular pads and facilitates polarization treatment.

[0011] Preferably, the upper surface protective film has exposed notches on both sides at one end, and the positions of the exposed notches correspond to the positive rectangular pad and the negative rectangular pad.

[0012] The beneficial effects of this utility model are: by using positive electrode assemblies and negative electrode assemblies made of silver wire, the softness of the silver wire is utilized during assembly to improve the connection between the positive and negative conductive metal sheets, simplifying assembly and solving the problem of electrical conductivity between the positive and negative bus circuits and the conductive circuits in terms of structure. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model after an explosion;

[0014] Figure 2 This is a schematic diagram of the overall structure of this utility model;

[0015] Figure 3 This is a schematic diagram of the positive electrode assembly in this utility model;

[0016] Figure 4 This is a flowchart of the production and preparation process of this utility model.

[0017] In the figure: 1. Micro piezoelectric unit; 2. Adhesive fiber; 3. Positive conductive metal sheet; 4. Negative conductive metal sheet; 5. Reinforcing frame; 6. Positive electrode assembly; 7. Negative electrode assembly; 8. Upper surface protective film; 9. Lower surface protective film; 10. Positive electrode etching groove; 11. Negative electrode etching groove; 12. Positive electrode rectangular pad; 13. Negative electrode rectangular pad; 14. Exposed notch. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figures 1-3 As shown, an electrode structure for a piezoelectric sensor includes an array of micro-piezoelectric units 1. Multiple adhesive fibers 2, with a length consistent with the longitudinal length of the array, are arranged between the lateral spacing of the micro-piezoelectric units 1. Multiple alternating positive and negative conductive metal sheets 3 and 4 are arranged between the longitudinal spacing of the micro-piezoelectric units 1. A reinforcing frame 5 is arranged on the outer side of the array of micro-piezoelectric units 1. Positive electrode assemblies 6 and negative electrode assemblies 7 are respectively adhered to both sides of the upper surface of the reinforcing frame 5. The positive electrode assembly 6 is connected to the multiple positive conductive metal sheets 3, and the negative electrode assembly 7 is connected to the multiple negative conductive metal sheets 4. The positive electrode assembly 6 is connected to the negative electrode assembly 4. The electrode assembly 7 is composed of silver wires. The upper and lower sides of the micro piezoelectric unit 1 and the reinforcing frame 5 are respectively covered with an upper surface protective film 8 and a lower surface protective film 9. One end of the upper surface protective film 8 has exposed notches 14 on both sides, and the position of the exposed notches 14 corresponds to the positive electrode rectangular pad 12 and the negative electrode rectangular pad 13. By bonding the fiber 2, the positive conductive metal sheet 3 and the negative conductive metal sheet 4, the arrayed micro piezoelectric units 1 are formed into a whole and fixed by the reinforcing frame 5. This not only improves the problem of uneven internal electric field, but also overcomes the problem of easy material detachment during the grinding process, which facilitates the preparation.

[0020] The upper surface protective film 8 and the lower surface protective film 9 are polyimide insulating coatings. The micro piezoelectric unit 1 is made of piezoelectric ceramic material with high d33 and g33 values. Its polarization direction is from the positive conductive metal sheet 3 to the negative conductive metal sheet 4. The positive conductive metal sheet 3 and the negative conductive metal sheet 4 are made of highly conductive copper or silver. The positive conductive metal sheet 3 and the negative conductive metal sheet 4 are bonded to the micro piezoelectric unit 1 by conductive silver paste. Both the positive conductive metal sheet 3 and the negative conductive metal sheet form a path by breaking down the adhesive fiber 2. The adhesive fiber 2 is made of flexible epoxy resin, and the adhesive fiber 2 is seamlessly bonded to the contact surface of the micro piezoelectric unit 1, allowing for charge movement without resistance. The reinforcing frame 5 is made of flexible epoxy resin. The contact surfaces of the positive electrode assembly 6, the reinforcing frame 5, and the adhesive fiber 2 are completely bonded, and there is no charge movement between the three. The contact surfaces of the negative electrode assembly 7, the reinforcing frame 5, and the adhesive fiber 2 are also completely bonded, and there is no charge movement between the three.

[0021] Positive electrode etching grooves 10 and negative electrode etching grooves 11 are etched on both sides of the reinforcing frame 5, respectively. The positive electrode assembly 6 is bonded to the inside of the positive electrode etching groove 10, and the negative electrode assembly 7 is bonded to the inside of the negative electrode etching groove 11. This facilitates wiring of the positive electrode assembly 6 and the negative electrode assembly 7, making fabrication easier. This solves the problem that when the positive electrode assembly or negative electrode assembly is fabricated by sputtering and other processes and then embedded in the etching groove, it cannot be aligned, resulting in poor or no connection between the surface electrode and the embedded electrode, leading to a low yield. A positive rectangular pad 12 is arranged at the end of the positive electrode etching groove 10, and the end of the positive electrode assembly 6 is welded to the positive rectangular pad 12. A negative rectangular pad 13 is arranged at the end of the negative electrode etching groove 11, and the end of the negative electrode assembly 7 is welded to the negative rectangular pad 13. This facilitates connection with external circuits through the positive rectangular pad 12 and the negative rectangular pad 13, and also facilitates polarization treatment.

[0022] During preparation, the process is as follows: Figure 4 As shown, the steps are as follows: 1. Adhere the piezoelectric ceramic to the metal sheet alternately from bottom to top using conductive silver paste ①; 2. After the conductive silver paste has cured, cut ① into a sheet shape according to the required thickness ②; 3. Make multiple non-penetrating, equidistant bonding fiber grooves ③ on the surface of the sheet ② along a direction perpendicular to the metal sheet; 4. Fill the grooves with flexible epoxy resin ④; 5. After the epoxy resin has cured, fill the outer perimeter with flexible epoxy resin. After curing, a reinforcing frame 5 is formed. Grind the upper and lower surfaces to remove the non-penetrating parts in ③ and grind to the required thickness ⑤; 6. Etch positively conductive metal sheet 3 and negatively conductive metal sheet 5 on both sides of the upper surface of the reinforcing frame 5. Etching grooves ⑥ are connected to the metal sheets 4; silver wires are used for wiring inside the etching grooves, and the ends of the silver wire bundles inside the same etching groove are soldered to the pad positions ⑦; after covering the positive rectangular pad 12 and the negative rectangular pad 13, a polyimide insulating protective layer of equal thickness is applied to the upper and lower surfaces of the whole ⑧; according to the longitudinal unit length L (mm) of the micro piezoelectric unit 1 of the array, the polarization voltage is applied to the positive rectangular pad 12 and the negative rectangular pad 13 using the voltage calculation formula V=2000×L (V), and the voltage is held for 20 minutes to polarize the micro piezoelectric unit 1 of the array, forming a sensor / exciter based on piezoelectric composite material ⑨. In the preparation process, the process is simple, the number of groove cuttings is reduced, and the unevenness of each cutting groove caused by the blade during each cutting is avoided, which effectively reduces the process difficulty and improves the yield.

[0023] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0024] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An electrode structure for a piezoelectric sensor, characterized by: The application relates to a micro piezoelectric unit (1) arranged in an array, a plurality of adhesive fibers (2) being arranged in the transverse interval of the micro piezoelectric unit (1) and being consistent with the longitudinal length of the array, a plurality of positive conductive metal sheets (3) and negative conductive metal sheets (4) being arranged in the longitudinal interval of the micro piezoelectric unit (1) and being positive and negative in alternation, a reinforcing frame (5) being arranged on the outer side of the array of the micro piezoelectric unit (1), and a positive electrode assembly (6) and a negative electrode assembly (7) being respectively adhered to the two sides of the upper surface of the reinforcing frame (5), the positive electrode assembly (6) being connected with the plurality of positive conductive metal sheets (3), the negative electrode assembly (7) being connected with the plurality of negative conductive metal sheets (4), the positive electrode assembly (6) and the negative electrode assembly (7) being arranged by silver wires, and upper surface protection films (8) and lower surface protection films (9) being respectively adhered to the upper and lower sides of the reinforcing frame (5).

2. The electrode structure of a piezoelectric sensor according to claim 1, characterized in that: The upper surface protection films (8) and the lower surface protection films (9) are polyimide insulating coatings, the material of the micro piezoelectric unit (1) is a piezoelectric ceramic material with high d33 and g33 values, and the polarization direction of the material is that the positive conductive metal sheets (3) point to the negative conductive metal sheets (4).

3. The electrode structure of a piezoelectric sensor according to claim 1, characterized by: The positive conductive metal sheets (3) and the negative conductive metal sheets (4) are made of high-conductivity copper or silver, and the positive conductive metal sheets (3) and the negative conductive metal sheets (4) are connected with the micro piezoelectric unit (1) by means of conductive silver glue.

4. The electrode structure of a piezoelectric sensor according to claim 1, characterized by: The material of the adhesive fibers (2) is flexible epoxy resin, the contact surface between the adhesive fibers (2) and the micro piezoelectric unit (1) is seamlessly adhered, and the material of the reinforcing frame (5) is flexible epoxy resin.

5. The electrode structure of a piezoelectric sensor according to claim 4, characterized in that: The two sides of the reinforcing frame (5) are respectively etched to form positive electrode etching grooves (10) and negative electrode etching grooves (11), the positive electrode assembly (6) is adhered in the positive electrode etching grooves (10), and the negative electrode assembly (7) is adhered in the negative electrode etching grooves (11).

6. The electrode structure of a piezoelectric sensor according to claim 5, characterized in that: The end of the positive electrode etching groove (10) is provided with a positive rectangular pad (12), the end of the positive electrode assembly (6) is welded on the positive rectangular pad (12), the end of the negative electrode etching groove (11) is provided with a negative rectangular pad (13), and the end of the negative electrode assembly (7) is welded on the negative rectangular pad (13).

7. The electrode structure of a piezoelectric sensor according to claim 6, characterized in that: One end of the upper surface protection film (8) is provided with exposed notches (14) on both sides, and the positions of the exposed notches (14) correspond to the positive rectangular pad (12) and the negative rectangular pad (13).

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