A novel flux modulation structure suitable for suppressing 1 / f noise in magnetic sensors

Abstract

This invention belongs to the field of low-frequency detection technology for magnetic sensors, and discloses a novel magnetic flux modulation structure suitable for suppressing 1 / f noise in magnetic sensors. It includes an insulating substrate, a micro-vibration beam disposed on the insulating substrate, one end of which corresponds to a focusing component disposed on the insulating substrate, and an electrode assembly disposed on the micro-vibration beam. The micro-vibration beam includes a fixed section fixed to the insulating substrate, and a free section fixed to the fixed section at a distance from the insulating substrate. The focusing component includes a first magnetic flux focusing unit and a second magnetic flux focusing unit symmetrically fixed to the insulating substrate, with one end of the free section extending into the gap between the first and second magnetic flux focusing units. This invention has a relatively simple structure and can effectively suppress 1 / f noise in TMR magnetic sensors. It modulates the measured magnetic field by relying on the vibration of the magnetic sensor, modulating the low-frequency signal to the high-frequency region to achieve the function of suppressing 1 / f noise. It has advantages such as high modulation efficiency and simple modulation structure implementation.

Description

Technical Field

[0001] This invention belongs to the field of low-frequency detection technology of magnetic sensors, and particularly relates to a novel magnetic flux modulation structure suitable for suppressing 1 / f noise of magnetic sensors. Background Technology

[0002] Tunneling magnetoresistance (TMR) sensors possess advantages such as high sensitivity, wide linear range, small size, and low power consumption, and are expected to be developed into miniaturized, high-performance magnetic sensors in the future. However, TMR magnetic sensors exhibit high 1 / f noise at low frequencies, which severely reduces their low-frequency detection capability. Researchers have proposed various methods to suppress 1 / f noise in magnetic sensors, which can be categorized into three types based on their implementation: magnetic flux modulation, electrical signal modulation, and sensitivity characteristic modulation. In terms of 1 / f noise suppression capability, magnetic flux modulation is more effective at suppressing the adverse effects of 1 / f noise on the detection capability of magnetic sensors and is currently the most widely used modulation method.

[0003] Magnetic flux modulation technology modulates the measured magnetic field to a high-frequency region from the perspective of the measured magnetic field, thereby avoiding the influence of 1 / f noise and improving the low-frequency detection capability of magnetic sensors. Currently, most existing magnetic flux modulation techniques rely on the vibration of the modulation film or the vibration of the magnetic flux concentrator to modulate the measured magnetic field. No method has been proposed that relies on the vibration of the magnetic sensor to achieve the modulation of the measured magnetic field. Furthermore, existing methods suffer from problems such as the difficulty in fabricating the modulation structure and the need to improve modulation efficiency.

[0004] Therefore, this application designs a novel flux modulation structure suitable for suppressing 1 / f noise of magnetic sensors to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a novel flux modulation structure suitable for suppressing 1 / f noise in magnetic sensors.

[0006] To achieve the above objectives, the present invention provides a novel flux modulation structure suitable for suppressing 1 / f noise of a magnetic sensor, comprising an insulating substrate, a micro-vibration beam disposed on the insulating substrate, one end of the micro-vibration beam being correspondingly disposed with an aggregation component disposed on the insulating substrate, and an electrode assembly disposed on the micro-vibration beam;

[0007] The micro-vibration beam includes a fixed section fixed to the insulating substrate, and one end of a free section fixed to the fixed section, with the free section suspended on the insulating substrate.

[0008] The gathering assembly includes a first flux gatherer and a second flux gatherer symmetrically fixed on the insulating substrate, with a gap between the first flux gatherer and the second flux gatherer, and the free segment extending into the gap from the fixed end.

[0009] Preferably, the electrode assembly includes a piezoelectric component and a second pair of electrodes, the piezoelectric component being fixed to the top end of the free segment and the second pair of electrodes being fixed to the bottom end of the free segment.

[0010] Preferably, the piezoelectric component includes an electrically connected pair of piezoelectric electrodes and a feedback electrode, the pair of piezoelectric electrodes being fixed to the top end of the free section, and the feedback electrode being fixed to the top end of the fixed section tube.

[0011] Preferably, a magnetic sensor element is fixedly connected to one end of the bottom surface of the free segment away from the fixed segment, and the magnetic sensor element is electrically connected to the second pair of electrodes.

[0012] Preferably, the piezoelectric electrode is arranged vertically corresponding to the second pair of electrodes.

[0013] Preferably, the width of the end of the first flux aggregator opposite to the second flux aggregator is smaller than the width of the end away from the second flux aggregator.

[0014] Preferably, the first flux concentrator and the second flux concentrator are made of soft magnetic material.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: The present invention discloses a novel magnetic flux modulation structure suitable for suppressing 1 / f noise of magnetic sensors. It relies on the resonance of the magnetic sensor to achieve modulation of the measured magnetic field, modulating the measured magnetic field to a high-frequency magnetic field, thereby suppressing the adverse effects of low-frequency 1 / f noise and improving the low-frequency detection performance of the magnetic sensor. A free section of a micro-vibration beam is provided in the gap between the first and second magnetic flux concentrators. The electrode assembly on the micro-vibration beam drives the magnetic sensor element to resonate in the gap region between the first and second magnetic flux concentrators by using piezoelectric drive, so as to achieve the purpose of modulating the measured magnetic field. It has the advantages of high modulation efficiency and relatively simple process implementation.

[0016] The present invention has a relatively simple structure and can effectively suppress 1 / f noise of TMR magnetic sensor. It adopts piezoelectric driving method and relies on the vibration of magnetic sensor to modulate the measured magnetic field, modulate the low frequency signal to the high frequency region, and realize the function of suppressing 1 / f noise. It has the advantages of high modulation efficiency and simple modulation structure. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 This is a schematic diagram of a novel magnetic flux modulation structure applicable to suppressing 1 / f noise in magnetic sensors according to the present invention;

[0019] Figure 2 This is a schematic diagram of the magnetic flux concentrator of the present invention;

[0020] Figure 3 This is a top view of the micro-vibration beam of the present invention;

[0021] Figure 4 This is a bottom view of the micro-vibration beam of the present invention;

[0022] In the figure: 1. Insulating substrate; 2. Micro-vibration beam; 3. Piezoelectric component; 4. Piezoelectric electrode pair; 5. Second pair of electrodes; 6. Magnetic sensor element; 7. First magnetic flux concentrator; 8. Second magnetic flux concentrator; 9. Feedback electrode; 10. Gap. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Reference Figures 1-4 As shown, this embodiment provides a novel flux modulation structure suitable for suppressing 1 / f noise of a magnetic sensor, including an insulating substrate 1, a micro-vibration beam 2 disposed on the insulating substrate 1, one end of the micro-vibration beam 2 being correspondingly disposed with an aggregation component disposed on the insulating substrate 1, and an electrode assembly disposed on the micro-vibration beam 2;

[0026] The micro-vibration beam 2 includes a fixed section fixed to the insulating substrate 1, and one end of a free section fixed to the fixed section, with the free section suspended on the insulating substrate 1.

[0027] The gathering assembly includes a first flux gatherer 7 and a second flux gatherer 8 symmetrically fixed on an insulating substrate 1. A gap 10 is provided between the first flux gatherer 7 and the second flux gatherer 8, and the free end away from the fixed end extends into the gap 10.

[0028] This invention discloses a novel magnetic flux modulation structure suitable for suppressing 1 / f noise in magnetic sensors. It modulates the measured magnetic field by relying on the resonance of the magnetic sensor, modulating the measured magnetic field to a high-frequency region, thereby suppressing the adverse effects of low-frequency 1 / f noise and improving the low-frequency detection performance of the magnetic sensor. A free section of a micro-vibrating beam 2 is provided between the gap 10 between the first magnetic flux concentrator 7 and the second magnetic flux concentrator 8. The electrode assembly on the micro-vibrating beam 2 uses piezoelectric drive to drive the magnetic sensor element 6 to resonate within the gap 10 region between the first and second magnetic flux concentrators 7 and 8, achieving the purpose of modulating the measured magnetic field. This invention has the advantages of high modulation efficiency and relatively simple manufacturing process. The structure of this invention is relatively simple and can effectively suppress 1 / f noise in TMR magnetic sensors. It uses piezoelectric drive to modulate the measured magnetic field by relying on the vibration of the magnetic sensor, modulating the low-frequency signal to the high-frequency region to achieve the function of suppressing 1 / f noise. It has advantages such as high modulation efficiency and simple modulation structure implementation.

[0029] A further optimized design includes an electrode assembly comprising a piezoelectric component 3 and a second pair of electrodes 5. The piezoelectric component 3 is fixed to the top of the free section, and the second pair of electrodes 5 is fixed to the bottom of the free section. The piezoelectric component 3 includes an electrically connected pair of piezoelectric electrodes 4 and a feedback electrode 9. The piezoelectric electrode pair 4 is fixed to the top of the free section, and the feedback electrode 9 is fixed to the top of the fixed section tube. A magnetic sensor element 6 is fixed to the bottom surface of the free section away from the fixed section, and the magnetic sensor element 6 is electrically connected to the second pair of electrodes 5. The piezoelectric electrodes and the second pair of electrodes 5 are arranged vertically in correspondence. (See attached diagram.) Figure 3 and attached Figure 4 The piezoelectric component 3 is fixed to the upper surface of the micro-vibrating beam 2, including a pair of piezoelectric electrodes 4 and a feedback electrode 9. The piezoelectric electrode pair 4 is connected to the piezoelectric component 3 and to an external excitation circuit, which can realize the resonance of the micro-vibrating beam 2. The feedback electrode 9 is attached to the fixed section and is connected to an external holding circuit, which can maintain the micro-vibrating beam 2 in the optimal resonance state. The second pair of electrodes 5 is connected to the magnetic sensor element 6, including a sensor excitation electrode and a sensor sensing electrode. The sensor excitation electrode is connected to an external current source, and the sensor sensing electrode is connected to an external demodulation circuit, which can realize the measurement of the ambient magnetic field.

[0030] Furthermore, the magnetic sensor element 6 is fixed to the bottom of the free section by adhesive bonding, and piezoelectric electrode pairs 4 are provided on the surface of the micro-vibration beam 2 above the magnetic sensor.

[0031] Furthermore, the vibration excitation electrode of the piezoelectric electrode pair 4 is connected to the external vibration excitation circuit, so that it generates periodic vibration in the form of sine or cosine, which in turn drives the free segment of the micro-vibration beam 2 to vibrate.

[0032] Furthermore, in this embodiment, the magnetic sensor element 6 is fixed to the bottom of the micro-vibration beam 2 by using epoxy resin adhesive.

[0033] Furthermore, the piezoelectric component 3 is made of piezoelectric material pmn-pt single crystal.

[0034] In a further optimized design, the width of the end of the first flux concentrator 7 opposite to the second flux concentrator 8 is smaller than the width of the end farther from the second flux concentrator 8; the first flux concentrator 7 and the second flux concentrator 8 are made of soft magnetic material. (See attached diagram.) Figure 2 The first magnetic flux concentrator 7 and the second magnetic flux concentrator 8 are made of soft magnetic material and fixed on the insulating substrate 1. Their shape is that the width of the opposite section is small and the width of the opposite end is large, and the whole structure is set into a fish tail shape. The magnetic field to be measured in the gap 10 is amplified under the action of the first magnetic flux concentrator 7 and the second magnetic flux concentrator 8, which facilitates the action on the micro-vibration beam 2 located in the gap 10.

[0035] Furthermore, the first flux concentrator 7 and the second flux concentrator 8 in this embodiment are made of Metglas, a soft magnetic material with high permeability. The specific material is not limited to this embodiment and may also be other soft magnetic materials with high permeability.

[0036] Furthermore, in this embodiment, the magnetic sensor element 6 is a tunnel junction magnetoresistive sensor or a giant magnetoresistive sensor.

[0037] How to use:

[0038] When the entire structure starts working, the micro-vibrating beam 2 drives the magnetic sensor element 6 to resonate under the external piezoelectric drive, which causes the measured magnetic field in the gap 10 to change from a low-frequency weak magnetic field to a high-frequency magnetic field. The magnetic flux amplification effect of the first magnetic flux concentrator 7 and the second magnetic flux concentrator 8 amplifies the weak magnetic field and suppresses the adverse effect of 1 / f noise of the magnetic sensor element 6. The magnetic sensor element 6 can also detect useful signals well in a low-frequency magnetic field environment, thereby improving the low-frequency detection capability of the magnetic sensor.

[0039] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A novel flux modulation structure suitable for suppressing 1 / f noise in magnetic sensors, characterized in that: It includes an insulating substrate (1), on which a micro-vibration beam (2) is disposed, one end of which is correspondingly disposed with an aggregation component disposed on the insulating substrate (1), and an electrode assembly is disposed on the micro-vibration beam (2); The micro-vibration beam (2) includes a fixed section fixed to the insulating substrate (1), and one end of a free section fixed to the fixed section, the free section being suspended on the insulating substrate (1). The gathering assembly includes a first flux gatherer (7) and a second flux gatherer (8) symmetrically fixed on the insulating substrate (1), with a gap (10) provided between the first flux gatherer (7) and the second flux gatherer (8), and one end of the free segment away from the fixed end extending into the gap (10); The electrode assembly includes a piezoelectric component (3) and a second pair of electrodes (5), wherein the piezoelectric component (3) is fixed to the top end of the free segment and the second pair of electrodes (5) is fixed to the bottom end of the free segment; The piezoelectric component (3) includes an electrically connected pair of piezoelectric electrodes (4) and a feedback electrode (9). The pair of piezoelectric electrodes (4) is fixed to the top end of the free section, and the feedback electrode (9) is fixed to the top end of the fixed section tube. A magnetic sensor element (6) is fixedly connected to one end of the bottom surface of the free section away from the fixed section, and the magnetic sensor element (6) is electrically connected to the second pair of electrodes (5); The width of the end of the first flux gatherer (7) opposite to the second flux gatherer (8) is smaller than the width of the end away from the second flux gatherer (8).

2. The novel flux modulation structure for suppressing 1 / f noise in a magnetic sensor according to claim 1, characterized in that: The piezoelectric electrode is positioned vertically and vertically corresponding to the second pair of electrodes (5).

3. The novel flux modulation structure for suppressing 1 / f noise in a magnetic sensor according to claim 1, characterized in that: The first flux concentrator (7) and the second flux concentrator (8) are made of soft magnetic material.

Images