阅读说明：本技术 一种基于磁扭电效应的磁场传感器及其制造方法 (Magnetic field sensor based on magnetic torsional electric effect and manufacturing method thereof ) 是由 刘明 胡忠强 吴金根 周子尧 王志广 于 2019-09-26 设计创作，主要内容包括：一种基于磁扭电效应的磁场传感器及其制造方法,包括压电材料、弹性层材料、永磁体材料、柔性电极、以及压电材料的上表面电极、下表面电极；压电材料的上、下表面贴合柔性电极,并以三明治结构封装于弹性层之间,压电材料位于弹性层长度方向的中心位置,弹性层的两端各自粘接一对永磁体,永磁体材料在外磁场的作用下产生扭矩,并对压电材料产生压应力的作用,压电材料产生电信号输出,继而实现对外界直流磁场、交流磁场的传感。本发明的磁场传感器,相比于常见的磁电传感器,无需偏置磁场,驱动简单,能耗低,基于磁扭电的悬臂梁结构也大大提高了传感器的使用寿命。(A magnetic field sensor based on a magnetic-torsional-electric effect and a manufacturing method thereof comprise a piezoelectric material, an elastic layer material, a permanent magnet material, a flexible electrode, and an upper surface electrode and a lower surface electrode of the piezoelectric material; the upper surface and the lower surface of the piezoelectric material are attached to the flexible electrodes and are packaged between the elastic layers in a sandwich structure, the piezoelectric material is located in the center of the elastic layers in the length direction, a pair of permanent magnets are respectively bonded to the two ends of the elastic layers, the permanent magnets generate torque under the action of an external magnetic field and generate pressure stress on the piezoelectric material, the piezoelectric material generates electric signals to be output, and then sensing of the external direct-current magnetic field and the external alternating-current magnetic field is achieved. Compared with a common magnetoelectric sensor, the magnetic field sensor provided by the invention does not need a bias magnetic field, is simple to drive and low in energy consumption, and the service life of the sensor is greatly prolonged based on the cantilever beam structure of the magnetic torsion electricity.)

1. A magnetic field sensor based on a magnetic-torsional-electric effect is characterized by comprising a piezoelectric material (1), an elastic layer material (2), a permanent magnet material (3) and a flexible electrode (4); two flexible electrodes (4) are attached to the upper surface and the lower surface of the piezoelectric material (1); the piezoelectric material (1) adhered with the flexible electrode (4) is packaged by two layers of elastic layer materials (2) in a sandwich structure, the piezoelectric material (1) is packaged at the central position of the elastic layer materials (2) in the length direction, and the flexible electrode (4) and the piezoelectric material (1) are positioned between interlayers of the two layers of elastic layer materials (2); the four permanent magnet materials with the same size are divided into two pairs, the two pairs of permanent magnet materials (3) are respectively bonded to two ends of the packaged elastic layer material (2), and the permanent magnet materials (3) at the same end are respectively bonded to the upper surface and the lower surface of the packaged elastic layer material (2); the piezoelectric material (1) comprises an upper electrode surface (5) and a lower electrode surface (6), and the piezoelectric material (1) is of a sheet structure.

2. Magnetic field sensor based on the magneto-electric effect according to claim 1, characterized in that the piezoelectric material (1) is AlN, quartz, LiNbO₃、BaTiO₃、ZnO、Pb(Zr,Ti)O₃、Pb(Mg,Nb)O₃-PbTiO₃、Pb(Zn,Nb)O₃-PbTiO₃Or BiScO₃-PbTiO₃One of (1); the elastic layer material (2) is in a long strip sheet shape and is one of Cu, Fe, Ni, Ti or Al.

3. The magnetic field sensor based on the magnetoelectric effect according to claim 1, wherein the permanent magnet material (3) is one of an aluminum-nickel-cobalt system permanent magnet alloy, an iron-chromium-cobalt system permanent magnet alloy, a permanent magnetic ferrite or a rare earth permanent magnet material.

4. The magnetic field sensor based on the magnetoelectric effect according to claim 1, wherein the base material of the flexible electrode (4) is one of PET, PDMS, PE, PVC or PP, and the conductive material of the flexible electrode (4) is one of Au, Ag, Al, Cu, Pt or Ni.

5. A magnetic field sensor based on the magnetoelectric effect according to claim 1, characterized in that the material of the upper electrode surface (5) and the lower electrode surface (6) is one of Au, Ag, Al, Cu, Pt, W, Fe, Co, Ni or Ti.

6. The magnetic field sensor based on the magnetoelectric effect according to claim 1, wherein the piezoelectric material (1) has a length of 1-5mm, a width of 1-5mm and a thickness of less than 1 mm; the length of the elastic layer material (2) is 1-30mm, the width is 1-5mm, and the thickness is less than 0.1 mm; the length of the permanent magnet material (3) is less than half of the length of the elastic layer material (2), the width of the permanent magnet material (3) is less than the width of the elastic layer material (2), and the magnetization direction of the permanent magnet material (3) is the thickness or length direction of the permanent magnet material.

7. A method for manufacturing a magnetic field sensor based on a magnetic-electric-torsional effect, wherein the magnetic field sensor based on the magnetic-electric-torsional effect is as claimed in any one of claims 1 to 6, and comprises the following steps:

step 1, providing a piezoelectric material (1), cutting the piezoelectric material into required sizes, and ultrasonically cleaning the piezoelectric material by using ultrapure water;

step 2, plating electrodes on electrode surfaces (5) and (6) on the upper surface and the lower surface of the piezoelectric material (1) in a silver paste annealing, evaporation or magnetron sputtering mode;

step 3, polarizing the piezoelectric material (1) in the thickness direction after electrodes are manufactured;

step 4, two flexible electrodes (4) are attached to the electrode surfaces (5) and (6) and used for conducting electric signals, the conductive material of the flexible electrodes (4) is not a full-coverage substrate, a small amount of epoxy resin is coated in the gap position of the conductive material in a proper amount and is cured for 24 hours at room temperature and used for bonding the flexible electrodes (4) and the piezoelectric material (1);

step 5, sticking the piezoelectric material (1) of the flexible electrode (4), packaging the piezoelectric material between two elastic layer materials (2) by taking epoxy resin as an adhesive, and curing the epoxy resin for 24 hours at room temperature;

step 6, dividing four permanent magnet materials with the same size into two pairs, adhering the two pairs of permanent magnet materials (3) to two free ends of the elastic layer material (2) encapsulated with the piezoelectric material (1) by using epoxy resin, and curing for 24 hours at room temperature;

and 7, welding a lead at the output end of the flexible electrode (4) so as to lead out a signal.

Technical Field

The invention belongs to the technical field of sensors, and particularly relates to a magnetic field sensor structure based on a magnetic-torsional-electric effect and a manufacturing method thereof.

Background

The conventional magnetoelectric sensor is mainly composed of a magnetostrictive material and a piezoelectric/ferroelectric material, and the magnetostrictive material and the piezoelectric/ferroelectric material interact with each other through a magnetic-elastic-electric coupling theory to realize the mutual conversion from electric polarization to magnetization. Strain is a key factor in "magneto-elastic-electric" coupling, and in order to obtain higher magneto-electric response, it is usually necessary to apply a dc bias magnetic field to the magnetostrictive material so that it reaches the position of maximum slope in the strain-magnetic field curve. The magnetoelectric sensor in this way has the following defects: firstly, an external Helmholtz coil is required to provide a direct-current bias magnetic field for the Helmholtz coil, so that the Helmholtz coil cannot be a passive device and is not beneficial to wide application; secondly, the required dc bias magnetic field is often very high, for example, the dc bias magnetic field of Terfenol-D magnetostrictive material is up to several hundred to several thousand Oe, and the dc bias magnetic field of Metglas magnetostrictive material is up to several Oe, which require high current to be input to the helmholtz coil to maintain the dc bias magnetic field when in use, thereby greatly increasing the energy consumption of the device and the heat generation of the system.

Disclosure of Invention

The invention aims to provide a magnetic field sensor structure based on a magnetic-torsional-electric effect and a manufacturing method thereof, so as to solve the problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

a magnetic field sensor based on a magnetic-torsional-electric effect comprises a piezoelectric material, an elastic layer material, a permanent magnet material and a flexible electrode; two flexible electrodes are attached to the upper surface and the lower surface of the piezoelectric material; the piezoelectric material adhered with the flexible electrode is packaged by two layers of elastic layer materials in a sandwich structure, the piezoelectric material is packaged at the central position of the elastic layer materials in the length direction, and the flexible electrode and the piezoelectric material are positioned between interlayers of the two layers of elastic layer materials; the four permanent magnet materials with the same size are divided into two pairs, the two pairs of permanent magnet materials are respectively bonded to two ends of the packaged elastic layer material, and the permanent magnet materials at the same end are respectively bonded to the upper surface and the lower surface of the packaged elastic layer material; the piezoelectric material comprises an upper electrode surface and a lower electrode surface, and is of a sheet structure.

Further, the piezoelectric material is AlN, quartz or LiNbO₃、BaTiO₃、ZnO、Pb(Zr,Ti)O₃、Pb(Mg,Nb)O₃-PbTiO₃、Pb(Zn,Nb)O₃-PbTiO₃Or BiScO₃-PbTiO₃One of (1); the elastic layer is made of a long strip sheet-shaped material, and is one of Cu, Fe, Ni, Ti or Al.

Further, the permanent magnet material is one of an aluminum-nickel-cobalt permanent magnet alloy, an iron-chromium-cobalt permanent magnet alloy, a permanent magnetic ferrite or a rare earth permanent magnet material.

Furthermore, the substrate material of the flexible electrode is one of polyethylene glycol terephthalate (PET), Polydimethylsiloxane (PDMS), Polyethylene (PE), polyvinyl chloride (PVC) or polypropylene (PP), and the conductive material in the flexible electrode is one of Au, Ag, Al, Cu, Pt or Ni.

Furthermore, the material of the upper electrode surface and the lower electrode surface is one of Au, Ag, Al, Cu, Pt, W, Fe, Co, Ni or Ti.

Further, the length of the piezoelectric material is 1-5mm, the width is 1-5mm, and the thickness is less than 1 mm; the length of the elastic layer material is 1-30mm, the width is 1-5mm, and the thickness is less than 0.1 mm; the length of the permanent magnet material is less than half of the length of the elastic layer material, the width of the permanent magnet material is less than the width of the elastic layer material, and the magnetization direction of the permanent magnet material is the thickness or length direction of the permanent magnet material.

Further, a manufacturing method of the magnetic field sensor based on the magnetic-torsional-electric effect comprises the following steps:

step 1, providing a piezoelectric material, cutting the piezoelectric material into required size, and ultrasonically cleaning the piezoelectric material by using ultrapure water;

step 2, plating electrodes on the electrode surfaces of the upper surface and the lower surface of the piezoelectric material in a silver paste annealing, evaporation or magnetron sputtering mode;

step 3, polarizing the piezoelectric material in the thickness direction after electrodes are manufactured;

step 4, two flexible electrodes are attached to the electrode surface and used for conducting electric signals, the conductive material of the flexible electrodes is not a full-coverage substrate, a small amount of epoxy resin is coated in the gap position of the conductive material in a proper amount, and the conductive material is cured for 24 hours at room temperature and used for bonding the flexible electrodes and the piezoelectric material;

step 5, sticking the piezoelectric material of the flexible electrode, packaging the piezoelectric material between two elastic layer materials by taking epoxy resin as an adhesive, and curing the epoxy resin for 24 hours at room temperature;

step 6, dividing four permanent magnet materials with the same size into two pairs, adhering the two pairs of permanent magnet materials to two free ends of the elastic layer material packaged with the piezoelectric material by using epoxy resin, and curing for 24 hours at room temperature;

and 7, welding a lead at the output end of the flexible electrode so as to lead out a signal.

Compared with the prior art, the invention has the following technical effects:

the magnetoelectric sensor based on the magnetoelectric effect can be used without an external direct-current bias magnetic field, so that the energy consumption of the device is greatly reduced, and the application range of the device is expanded. Meanwhile, the cantilever beam structure is different from the traditional cantilever beam structure, the excitation of the piezoelectric material in the traditional cantilever beam structure takes strain as a medium, and the service life of the cantilever beam structure is not long due to the brittleness of the piezoelectric material. The cantilever beam structure of the invention is a sandwich structure, the excitation of the piezoelectric material takes stress as a medium, the piezoelectric material works in a compression mode, and the service life is greatly prolonged.

Drawings

FIG. 1 is a schematic structural view of the present invention;

wherein: 1. a piezoelectric material; 2. an elastic layer material; 3. a permanent magnet material; 4. a flexible electrode; 5 an upper electrode face of piezoelectric material; 6. a lower electrode surface of the piezoelectric material.

FIG. 2 is a schematic view of the magnetization direction of a permanent magnet material;

FIG. 3 is a graph showing the results of testing the sensitivity of the AC and DC magnetic fields according to the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

referring to fig. 1 to 3, a magnetic field sensor based on a magnetic-torsional-electric effect includes a piezoelectric material 1, an elastic layer material 2, a permanent magnet material 3, and a flexible electrode 4; two flexible electrodes 4 are attached to the upper and lower surfaces of the piezoelectric material 1; the piezoelectric material 1 adhered with the flexible electrode 4 is packaged by two layers of elastic layer materials 2 in a sandwich structure, the piezoelectric material 1 is packaged at the central position of the elastic layer materials 2 in the length direction, and the flexible electrode 4 and the piezoelectric material 1 are positioned between interlayers of the two layers of elastic layer materials 2; the four permanent magnet materials with the same size are divided into two pairs, the two pairs of permanent magnet materials 3 are respectively bonded to two ends of the packaged elastic layer material 2, and the permanent magnet materials 3 at the same end are respectively bonded to the upper surface and the lower surface of the packaged elastic layer material 2; the piezoelectric material 1 comprises an upper electrode surface 5 and a lower electrode surface 6, and the piezoelectric material 1 is of a sheet structure.

The piezoelectric material 1 is AlN, quartz or LiNbO₃、BaTiO₃、ZnO、Pb(Zr,Ti)O₃、Pb(Mg,Nb)O₃-PbTiO₃、Pb(Zn,Nb)O₃-PbTiO₃Or BiScO₃-PbTiO₃One of (1); the elastic layer material 2 is in a strip sheet shape and is one of Cu, Fe, Ni, Ti or Al.

The permanent magnet material 3 is one of an aluminum-nickel-cobalt permanent magnet alloy, an iron-chromium-cobalt permanent magnet alloy, a permanent magnetic ferrite or a rare earth permanent magnet material.

The substrate material of the flexible electrode 4 is one of polyethylene glycol terephthalate (PET), Polydimethylsiloxane (PDMS), Polyethylene (PE), polyvinyl chloride (PVC) or polypropylene (PP), and the conductive material in the flexible electrode 4 is one of Au, Ag, Al, Cu, Pt or Ni.

The material of the upper electrode surface 5 and the lower electrode surface 6 is one of Au, Ag, Al, Cu, Pt, W, Fe, Co, Ni or Ti.

The length of the piezoelectric material 1 is 1-5mm, the width is 1-5mm, and the thickness is less than 1 mm; the length of the elastic layer material 2 is 1-30mm, the width is 1-5mm, and the thickness is less than 0.1 mm; the length of the permanent magnet material 3 is less than half of the length of the elastic layer material 2, the width of the permanent magnet material 3 is less than the width of the elastic layer material 2, and the magnetization direction of the permanent magnet material 3 is the thickness or length direction.

When the magnetic field sensor is in operationThe middle position is clamped, the two cantilever beams can be regarded as two cantilever beams sharing the fixed end in mechanics, and the resonant frequency can be determined according to

The adjustment is carried out, h is the thickness of the cantilever beam, l is the length of the cantilever beam,

in the form of an average density,

V_eis the volume fraction, rho, of the epoxy resin in the cantilever beam_eIs the density of the epoxy resin, V_mIs the volume fraction, rho, of the elastic layer material in the cantilever beam_mIs the density of the elastic layer or layers,is the transverse modulus of elasticity of the cantilever beam,

E_mis the modulus of elasticity of the material of the elastic layer, E_eIs the modulus of elasticity of epoxy resin, β₁＝0.597,β₂＝1.494,……β_nN-0.5, n being the order of the cantilever bending mode.

Further, the piezoelectric material of the sensor operates in a compression mode, the material is subjected to a compressive stress, d₃₃The piezoelectric coefficient plays a leading role in the output of the sensor, and the piezoelectric material is selected from d₃₃Piezoelectric polycrystalline ceramic materials or single crystal materials with high piezoelectric coefficients. When the piezoelectric material is piezoelectric single crystal, the tangential direction of the crystal can be optimized to d₃₃The maximum effect.

A manufacturing method of a magnetic field sensor based on a magnetic-torsional-electric effect comprises the following steps:

step 1, providing a piezoelectric material 1, cutting the piezoelectric material into required sizes, and ultrasonically cleaning the piezoelectric material by using ultrapure water;

step 2, plating electrodes on electrode surfaces 5 and 6 on the upper surface and the lower surface of the piezoelectric material 1 in a silver paste annealing, evaporation or magnetron sputtering mode;

step 3, polarizing the piezoelectric material 1 in the thickness direction after electrodes are manufactured;

step 4, two flexible electrodes 4 are attached to the electrode surfaces 5 and 6 and used for conducting electric signals, the conductive material of the flexible electrodes 4 does not fully cover the substrate, a small amount of epoxy resin is coated in the gap position of the conductive material in a proper amount, and the conductive material is cured for 24 hours at room temperature and used for bonding the flexible electrodes 4 and the piezoelectric material 1;

step 5, sticking the piezoelectric material 1 of the flexible electrode 4, packaging the piezoelectric material between two elastic layer materials 2 by taking epoxy resin as an adhesive, and curing the epoxy resin for 24 hours at room temperature;

step 6, dividing four permanent magnet materials with the same size into two pairs, adhering two pairs of permanent magnet materials 3 to two free ends of the elastic layer material 2 encapsulated with the piezoelectric material 1 by using epoxy resin, and curing for 24 hours at room temperature; the magnetization direction of the permanent magnet is shown in FIG. 2, there can be 4 cases (A, B, C, D), and in the 4 cases, the permanent magnet can generate torque action on the elastic layer under the action of an external magnetic field;

and 7, welding a lead at the output end of the flexible electrode (4) so as to lead out a signal.

The sensor is used for detecting an alternating current magnetic field and a direct current magnetic field in a direction parallel to the sensor, and generates torque under the action of an external magnetic field by utilizing the permanent magnet material to generate a pressure stress action on the piezoelectric material, so that the conversion from a magnetic field signal to a voltage signal is realized.

The permanent magnet material is used for generating magnetic torque, and the magnetization direction of the permanent magnet material can be arranged in parallel or in anti-parallel along the thickness direction of the cantilever beam, and also can be arranged in parallel or in anti-parallel along the length direction of the cantilever beam.

FIG. 3 shows the results of testing the sensitivity of the AC and DC magnetic fields of the present invention, in comparison with a commercially available LakeShore425 Gaussmeter. (a) The alternating current signal detection result of the commercial LakeShore425Gaussmeter has the alternating current sensitivity of 8E-5T; (b) the direct current magnetic field detection waveform of the invention; (c) according to the alternating current magnetic field sensitivity test result, the alternating current sensitivity is 1E-7T; (d) the DC sensitivity of the DC magnetic field sensitivity test result of the invention is 0.01Oe, which is equivalent to the commercial LakeShore425Gaussmeter DC sensitivity (0.01 Oe);

the above examples of the present invention are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Variations and modifications in other variations will occur to those skilled in the art upon reading the foregoing description. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.