CN114966489A - Broadband magnetoelectric composite magnetic sensitive device and current detection device - Google Patents

Abstract

The invention discloses a magnetic field sensor and a broadband magnetoelectric composite magnetic sensitive device and a current detection device in the technical field of current detection, and aims to solve the problem that the detection bandwidth range of the magnetic field sensor device in the prior art is small. The broadband magnetoelectric composite magnetic sensitive device comprises a piezoelectric body, wherein the piezoelectric body comprises a plurality of piezoelectric areas with different thicknesses; piezoelectric regions with different thicknesses are respectively provided with respective first electrodes, and one side of each piezoelectric region, which is far away from the first electrodes, is provided with a common second electrode; each first electrode and each second electrode are respectively connected with a respective bonding pad; one sides of the first electrodes and the second electrodes, which are far away from the piezoelectric body, are respectively provided with magnetostrictive films, and the magnetostrictive films are not connected with each other; the invention is suitable for current detection work, can achieve the effect of improving the detection bandwidth of the magnetoelectric composite magnetic sensitive device, and ensures the applicability of the magnetoelectric composite magnetic sensitive device.

Description

Broadband magnetoelectric composite magnetic sensitive device and current detection device

Technical Field

The invention relates to a broadband magnetoelectric composite magnetic sensitive device and a current detection device, belonging to the technical field of magnetic field sensors and current detection.

Background

In recent years, with the continuous development of novel functional materials such as ferromagnetism, ferroelectricity, ferroelasticity and the like, magnetoelectric composite materials based on magnetostrictive materials and piezoelectric materials are developed, and the materials utilize the coupling effect magnetoelectric effect of the magnetostrictive effect and the piezoelectric effect to realize the detection of a magnetic field. The magnetic field sensor based on the magnetoelectric composite material is expected to meet the requirements of various important applications on comprehensive performances such as high sensitivity, low power consumption, miniaturization, wide range, low cost, room-temperature operation, vector type detection and the like due to the unique working principle and the unique structural composition. As mentioned above, the essence of the non-contact measurement of the current is to measure the magnetic field generated by the current, therefore, the novel magnetic field sensor provides a new idea for current detection.

The current magnetic field sensor can realize the detection bandwidth from direct current to 20kHz, but because the intrinsic resonance frequency bandwidth of the piezoelectric matrix is not infinite, some technical means need to be used for improving the detection bandwidth of the device aiming at the requirement of wider detection bandwidth.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a broadband magnetoelectric composite magnetic sensitive device and a current detection device, and solves the problem that the detection bandwidth range of a magnetic field sensor device is small.

In order to solve the technical problems, the invention is realized by adopting the following technical scheme:

the invention provides a broadband magnetoelectric composite magnetic sensitive device which comprises a piezoelectric body, wherein the piezoelectric body comprises a plurality of piezoelectric areas with different thicknesses; piezoelectric regions with different thicknesses are respectively provided with respective first electrodes, and one side of each piezoelectric region, which is far away from the first electrodes, is provided with a common second electrode; each first electrode and each second electrode are respectively connected with a respective bonding pad;

and magnetostrictive films are respectively arranged on the sides, far away from the piezoelectric body, of the first electrodes and the second electrodes, and the magnetostrictive films are not connected with each other.

Furthermore, the piezoelectric regions with different thicknesses are arranged in parallel in a step shape.

Further, for two adjacent piezoelectric regions, the thickness of the piezoelectric region with smaller thickness is not more than two thirds of the thickness of the piezoelectric region with larger thickness.

Further, the thickness of each first electrode is the same.

Furthermore, the bonding pads connected with the first electrode are mutually conducted.

Furthermore, the bonding pad is a metal film evaporated on the piezoelectric body.

Furthermore, the magnetostrictive films arranged on different first electrodes have different thicknesses.

Further, the number of the piezoelectric regions is at least three.

The invention also provides a current detection device which comprises the broadband magnetoelectric composite magnetic sensitive device.

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

1. according to the broadband magnetoelectric composite magnetic sensitive device, the piezoelectric body comprises a plurality of piezoelectric areas with different thicknesses, so that the piezoelectric body has a plurality of resonant frequencies, the detection bandwidth of the magnetoelectric composite magnetic sensitive device is improved, and the applicability of the magnetoelectric composite magnetic sensitive device is ensured;

2. by changing the thicknesses of the magnetostrictive films on different first electrodes, the magnetostrictive films corresponding to the piezoelectric regions with thicker thicknesses are thicker, and the corresponding electric signal amplitude is improved, so that the signal intensity loss is compensated, and the applicability of the invention is ensured.

Drawings

Fig. 1 is a schematic structural diagram of a broadband magnetoelectric composite magnetic sensing device provided according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a piezoelectric body of a broadband magnetoelectric composite magnetic sensitive device according to an embodiment of the present invention.

In the figure: 1. a piezoelectric body; 11. a first area; 12. a second area; 13. a third area; 21. a first electrode region I; 22. a second electrode region; 23. a first electrode region three; 3. a second electrode; 4. a fourth magnetostrictive film region; 51. a first magnetostrictive film region; 52. a second magnetostrictive film region; 53. a magnetostrictive film area III; 6. a first pad; 7. a second bonding pad.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The first embodiment is as follows:

as shown in fig. 1-2, the present invention provides a broadband magnetoelectric composite magnetic sensor, which includes a piezoelectric body 1, wherein the piezoelectric body 1 includes a plurality of piezoelectric regions with different thicknesses; piezoelectric regions with different thicknesses are respectively provided with respective first electrodes, and one side of each piezoelectric region, which is far away from the first electrodes, is provided with a common second electrode 3; each of the first electrode and the second electrode 3 is connected to a pad for energizing the piezoelectric body 1 and outputting a signal. The sides of the first electrodes and the second electrodes 3, which are far away from the piezoelectric body 1, are respectively provided with magnetostrictive films, and the magnetostrictive films are not connected with each other, so that the piezomagnetic effect of the magnetostrictive films is prevented from being influenced.

The working principle of the broadband magnetoelectric composite magnetic sensitive device provided by the embodiment of the invention is as follows: the magnetostrictive film is deformed after an external magnetic field is changed, and the piezoelectric body 1 deforms along with the deformation of the magnetostrictive film, so that certain electric charges are output, namely, the change of the magnetic field to be detected is converted into a voltage signal through a piezoelectric effect, and the detection work is finished.

Because the position of the magnetostrictive film is located on two sides of the thickness direction of the piezoelectric body 1, the magnetostrictive film performs an external force action along the thickness direction of the piezoelectric body 1, the resonant frequency of the piezoelectric body 1 is mainly determined by the thickness of the piezoelectric body, and a plurality of piezoelectric areas with different thicknesses are formed to have a plurality of resonant frequencies, so that the piezoelectric body 1 has a plurality of resonant frequencies, thereby improving the detection bandwidth of the magnetoelectric composite magnetic sensitive device and ensuring the applicability of the magnetoelectric composite magnetic sensitive device.

The piezoelectric body 1 is a material having a piezoelectric effect, and for example: PZT, PMVPT, PZMPT, and the like. In an embodiment, the piezoelectric regions with different thicknesses in the piezoelectric body 1 may be integrated, so that the piezoelectric regions with different thicknesses may be arranged in parallel in a step shape for convenience of production, installation and calibration. However, the piezoelectric elements may be arranged at random intervals. In order to avoid that the thicknesses of the two adjacent piezoelectric regions are too close to each other and the purpose of improving the detection bandwidth cannot be achieved, for the two adjacent piezoelectric regions, the thickness of the piezoelectric region with the smaller thickness is generally not more than two thirds of the thickness of the piezoelectric region with the larger thickness.

In this embodiment, the charges generated corresponding to each piezoelectric region are output by alternating current through the first electrode and the second electrode 3, and the thicknesses of the first electrodes are substantially the same, so that the influence of the piezoelectric body 1 on the induction of the deformation pressure of the magnetostrictive film due to the thickness deviation of the first electrodes is avoided, and the inconsistency of the temperature characteristics of each region of the piezoelectric body 1 is also avoided, thereby influencing the detection accuracy of the magnetoelectric composite magnetic sensitive device.

The bonding pads comprise a first bonding pad 6 and a second bonding pad 7, the second bonding pad 7 is electrically connected with the second electrode 3, the first bonding pad 6 is electrically connected with the plurality of first electrodes at the same time, the number of connecting lines and resistance loss when the piezoelectric regions with different thicknesses are independently connected with the first electrodes are reduced, and the practicability of the piezoelectric bonding pad is improved. The bonding pad can adopt a metal film (other modes such as sputtering, electroplating and the like) evaporated on the piezoelectric body 1, so that the using effect of the bonding pad is ensured.

In one embodiment, the magnetostrictive films disposed on different first electrodes have different thicknesses, the thicker magnetostrictive film has a larger deformation force, the resonant frequencies of piezoelectric regions with different thicknesses in the piezoelectric body 1 are different, and when the resonant frequencies are changed, the thicker piezoelectric body 1 deforms less under the same magnetostrictive film deformation force due to the thickness change of the piezoelectric body 1, which causes loss of signal strength and causes unevenness of frequency response. By changing the thicknesses of the magnetostrictive films on different first electrodes, the magnetostrictive films corresponding to the piezoelectric regions with thicker thicknesses are thicker, and the corresponding electric signal amplitude is improved, so that the signal intensity loss is compensated, and the applicability of the invention is ensured.

In one embodiment, there may be three piezoelectric regions, but the number of piezoelectric regions may be greater.

When the number of piezoelectric regions is three, for convenience of description, the three piezoelectric regions will be respectively named as a region one 11, a region two 12 and a region three 13, correspondingly, the first electrode includes a first electrode area one 21 corresponding to the area one 11, a second electrode area two 22 corresponding to the area two 12, and a third electrode area 23 corresponding to the area three 13 (which are adaptively adjusted according to the number of piezoelectric areas of the piezoelectric body 1), and the magnetostrictive film includes a first magnetostrictive film area one 51 disposed on the first electrode area one 21, a second magnetostrictive film area two 52 disposed on the first electrode area two 22, a third magnetostrictive film area 53 disposed on the first electrode area three 23 (which are adaptively adjusted according to the number of piezoelectric areas of the piezoelectric body 1), and a fourth magnetostrictive film area four 4 disposed on the second electrode 3.

Example two:

the embodiment of the invention also provides a current detection device, which comprises the broadband magnetoelectric composite magnetic sensitive device, and when the current detection device works for current detection, the piezoelectric body 1 has different resonant frequencies due to the piezoelectric body 1 having a plurality of piezoelectric areas with different thicknesses, so that the detection bandwidth of the current detection device is improved, and the application range of the current detection device is ensured.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims (9)

1. The broadband magnetoelectric composite magnetic sensitive device is characterized by comprising a piezoelectric body (1), wherein the piezoelectric body (1) comprises a plurality of piezoelectric areas with different thicknesses; piezoelectric regions with different thicknesses are respectively provided with respective first electrodes, and one side of each piezoelectric region, which is far away from the first electrodes, is provided with a common second electrode (3); each first electrode and each second electrode (3) are respectively connected with a bonding pad;

and magnetostrictive films are respectively arranged on the sides of the first electrodes and the second electrodes (3) far away from the piezoelectric body (1), and the magnetostrictive films are not connected with each other.

2. The broadband magnetoelectric composite magnetically sensitive device according to claim 1, wherein the piezoelectric regions of different thicknesses are arranged in parallel in a step shape.

3. The broadband magnetoelectric composite magnetically sensitive device according to claim 2, wherein for two adjacent piezoelectric regions, the thickness of the piezoelectric region with the smaller thickness is not more than two thirds of the thickness of the piezoelectric region with the larger thickness.

4. The broadband magnetoelectric composite magnetically sensitive device according to claim 1, wherein the thickness of each of the first electrodes is the same.

5. The broadband magnetoelectric composite magnetic sensitive device according to claim 1, wherein the bonding pads connected with the first electrode are in conduction with each other.

6. The broadband magnetoelectric composite magnetic sensitive device according to claim 1 or 5, wherein the bonding pad is a metal film evaporated on the piezoelectric body.

7. The broadband magnetoelectric composite magnetic sensitive device according to claim 1, characterized in that: the magnetostrictive films disposed on different first electrodes have different thicknesses.

8. The broadband magnetoelectric composite magnetic sensitive device according to claim 1, characterized in that: the piezoelectric regions are at least three.

9. A current detection device, characterized by comprising the broadband magnetoelectric composite magnetically sensitive device according to any one of claims 1 to 8.

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