A magnetic field light and dark grid device based on magnetic focusing effect

Abstract

A magnetic field bright / dark grating device based on magnetic focusing effect includes: a magnet platform, a magnetic field bright / dark grating assembly, and a substrate. The magnet platform is disposed on top of the magnetic field bright / dark grating assembly, and the substrate is disposed at the bottom of the magnetic field bright / dark grating assembly. The magnetic field bright / dark grating assembly includes: a support frame, an amplification platform, a support groove, and a high-permeability soft magnetic tunnel tip. The support groove is slidably disposed within the support frame and is horizontally positioned. Multiple amplification platforms are slidably disposed within the support groove, and a high-permeability soft magnetic tunnel tip is disposed at the bottom of the amplification platform. The beneficial effect of this invention is that by concentrating an approximately uniform magnetic field strength through the high-permeability soft magnetic tunnel tip, a stable and changing high-rate-of-change magnetic field is formed, causing the magnetoresistive field sensitivity to change drastically even under weak magnetic field changes. Furthermore, the designed magnetic field bright / dark grating structure has a simple processing technology, low manufacturing cost, ease of use, and high reliability, making it suitable for miniaturization.

Description

Technical Field

[0001] This invention relates to the field of magnetism, and more specifically to a magnetic field light and dark grid device based on the magnetic focusing effect. Background Technology

[0002] Magnetic sensors, with their non-contact measurement and non-affective properties, are widely used in medical, defense, and aerospace fields. Their principle is to measure physical parameters such as current, position, and direction by sensing changes in the magnetic field. The development of microelectromechanical systems (MEMS) technology has spurred a new generation of MEMS magnetic sensors. Their advantages, such as small size, low cost, and high reliability, have allowed them to rapidly capture a large application market. Types of magnetic sensors include Hall elements, semiconductor magnetoresistive devices, and strong magnet thin-film magnetoresistive devices. Semiconductor magnetoresistive devices mainly refer to InSb devices, which are generally used for weak magnetic field detection, primarily in counterfeit currency identification, pulse measurement, and rotational speed / revolution measurement. Giant magnetoresistive (GMR) sensors and tunneling magnetoresistive (TMR) sensors are two representative types of magnetoresistive devices, requiring high magnetic field change rates. A typical TMR magnetic sensor, such as the SOT23-5, controls the packaged volume to the micrometer level while maintaining a measurement range of 10... -3 ~10 -1 T, with a minimum resolution of 10. -8 Therefore, designing a stable magnetic field with a high rate of change is of great significance for improving the sensitivity of magnetic sensors.

[0003] With the trend towards miniaturization of devices, the size of the target object being measured is also decreasing. At the micro- and nano-scale, many magnets generate extremely weak magnetic fields, only about 10^- ... -4 With temperatures even lower than T, the sensitive detection area shrinks accordingly, thus pushing the detection sensitivity and resolution to their limits. Currently, even high-resolution magnetic sensors like GMR or TMR have insufficient range to meet measurement requirements. Therefore, how to utilize existing magnetic measurement devices to measure weak magnetic fields remains a challenge in current research.

[0004] Meanwhile, current permanent magnets, due to factors such as size, coercivity, and surface magnetism, often cannot generate large magnetic field strengths and high magnetic field change rates. Even when measuring the magnetic field within the device's measurement range, when the magnetic field change reaches the nT level or even lower, which is less than or close to the sensor's resolution, the sensor's measurement results will be inaccurate or even unusable. Therefore, obtaining high-rate magnetic field changes in weak magnetic environments is key to improving the sensitivity of MEMS magnetic sensors.

[0005] Magnetic field bright / dark grids utilize the magnetic concentration effect of soft magnetic materials to enhance local magnetic field strength, thereby increasing the rate of magnetic field change. The magnetic concentration effect refers to the phenomenon where, when a soft magnetic material with high permeability is placed in a magnetic field domain, the magnetic field strength near its edges and corners significantly increases. Through this magnetic concentration effect, a magnetic field strength much higher than the surrounding environment can be obtained at a certain point or near a certain line. Then, by utilizing this peak value, an extremely high rate of magnetic field change can be obtained while keeping the surrounding magnetic field constant. Summary of the Invention

[0006] To address the problem that magnetic sensors cannot measure extremely low magnetic field change rates under weak magnetic conditions, this invention proposes a magnetic field bright / dark grating device based on the magnetic focusing effect to stabilize high-variable magnetic field strength. The magnetic field bright / dark grating utilizes the magnetic focusing effect of high-permeability soft magnetic materials in a magnetic field to extend the lower limit of the measurement range of high-sensitivity MEMS magnetoresistive sensors by one to two orders of magnitude.

[0007] The soft magnetic material in this invention refers to a magnetic material with low coercivity and high permeability, which is easily magnetized but also easily demagnetized. Soft magnetic materials can achieve maximum magnetization with minimal external magnetic field strength; the higher the permeability of the material, the higher the magnetization strength. If a piece of high-permeability soft magnetic material is placed in a fixed magnetic field domain, the polarization direction of the material's magnetic domains tends to be consistent under the influence of the external magnetic field, and the material exhibits magnetism. Then, based on the magnetic field concentration effect, the magnetic field strength formed at the edges will exceed the magnetism of the magnet itself by one to two orders of magnitude. That is, the magnetic field strength reflected on the sensitive head of the magnetic sensor will be several times or even tens of times stronger than the external magnetic field. This amplification ensures that the measured magnetic field meets the lower limit of the sensor's range. Once the specific value is measured, the weak magnetic field can be measured using the known amplification factor. Furthermore, with the development of microfabrication technology, it is feasible to reduce the size of the magnetic field grating to a range compatible with MEMS devices.

[0008] A magnetic field bright-dark grid device based on magnetic focusing effect includes: a magnet platform, a magnetic field bright-dark grid assembly and a substrate, wherein the magnet platform is disposed on the top of the magnetic field bright-dark grid assembly and the substrate is disposed on the bottom of the magnetic field bright-dark grid assembly;

[0009] The magnetic field light and dark grid assembly includes: a support frame, an amplification platform, a support groove, and a high-permeability soft magnetic tip;

[0010] The support groove is slidably disposed within the support frame and is horizontally disposed. Multiple amplification platforms are slidably disposed within the support groove, and a high permeability soft magnetic tip is disposed at the bottom of the amplification platform.

[0011] Optionally, the magnet platform is located on top of the support frame and is used to place the magnet to be tested.

[0012] Optionally, the support groove and the support frame are slidably connected by a damping material or a damping fit.

[0013] Optionally, the high-permeability soft magnetic tunnel tip shape includes: a rectangular ring, a circular ring, or a triangular ring.

[0014] Optionally, the substrate is disposed at the bottom of the support frame, and a translational slide is provided on the substrate, wherein a magnetoresistor is slidably disposed within the translational slide.

[0015] Optionally, the magnet platform, support frame, support groove, magnification platform, translation slide, and substrate are made of materials that do not interfere with the magnetic field, including: phenolic plastic, polyurethane plastic, epoxy plastic, unsaturated polyester plastic, furan plastic, silicone resin, acrylic resin, copper, and platinum.

[0016] Optionally, the material of the high-permeability soft magnetic tunnel tip includes: MnZnt ferrite and NiFe alloy.

[0017] The beneficial effects of this invention are that by concentrating a nearly uniform magnetic field intensity through a high-permeability soft magnetic tunnel tip, a stable and rapidly changing magnetic field is formed. This causes the magnetoresistive sensor to detect even slight changes in the magnetic field, resulting in a dramatic change in its resistance. Furthermore, the designed magnetic field bright / dark grating structure is simple to manufacture, has low production costs, is easy to use, and has high reliability, making it suitable for miniaturization.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 This is a top view of the magnet being tested according to the present invention.

[0021] Figure 3 This is a schematic diagram of the magnetic field light and dark grid assembly structure of the present invention.

[0022] Figure 4 This is a front view of the cross-sectional structure of the present invention.

[0023] Figure 5 This is a schematic diagram of the substrate structure of the present invention.

[0024] Figure 6 This is a schematic diagram of the high permeability soft magnetic tunnel tip structure of the present invention.

[0025] Figure 7This is a schematic diagram illustrating the magnetic focusing effect of the three structures of the high permeability soft magnetic tunnel tip structure of the present invention on the magnetic field.

[0026] Figure 8 The high permeability soft magnetic tunnel tip of this invention adopts a rectangular ring structure and is modeled and simulated using COMSOL. The magnetic field strength in the Z-axis direction after changing the detection distance is shown in the figure. (1) is the magnetic field strength when the detection distance is 0 mm, (2) is the magnetic field strength when the detection distance is 0.01 mm, (3) is the magnetic field strength when the detection distance is 0.03 mm, and (4) is the magnetic field strength when the detection distance is 0.07 mm.

[0027] Figure 9 The high permeability soft magnetic tunnel tip of this invention adopts a rectangular ring structure and is modeled and simulated using COMSOL. The magnetic field strength change rate after changing the detection distance is shown in the figure. (1) is the magnetic field strength change rate when the detection distance is 0 mm, (2) is the magnetic field strength change rate when the detection distance is 0.01 mm, (3) is the magnetic field strength change rate when the detection distance is 0.03 mm, and (4) is the magnetic field strength change rate when the detection distance is 0.07 mm.

[0028] Figure 10 The high permeability soft magnetic tunnel tip of this invention adopts a circular ring structure and is modeled and simulated using COMSOL. The magnetic field strength in the Z-axis direction is changed after changing the detection distance. Among them: (1) is the magnetic field strength when the detection distance is 0mm, (2) is the magnetic field strength when the detection distance is 0.01mm, (3) is the magnetic field strength when the detection distance is 0.03mm, and (4) is the magnetic field strength when the detection distance is 0.07mm.

[0029] Figure 11 The high permeability soft magnetic tunnel tip of this invention adopts a circular structure and is modeled and simulated using COMSOL. The magnetic field strength change rate after changing the detection distance is shown in the following diagram: (1) is the magnetic field strength change rate when the detection distance is 0 mm, (2) is the magnetic field strength change rate when the detection distance is 0.01 mm, (3) is the magnetic field strength change rate when the detection distance is 0.03 mm, and (4) is the magnetic field strength change rate when the detection distance is 0.07 mm.

[0030] Figure 12 The high permeability soft magnetic tunnel tip of this invention adopts a triangular ring structure and is modeled and simulated using COMSOL. The magnetic field strength in the Z-axis direction after changing the detection distance is shown in the figure. (1) is the magnetic field strength when the detection distance is 0 mm, (2) is the magnetic field strength when the detection distance is 0.01 mm, (3) is the magnetic field strength when the detection distance is 0.03 mm, and (4) is the magnetic field strength when the detection distance is 0.07 mm.

[0031] Figure 13The diagram shows the rate of change of magnetic field strength at the detection distance after modeling and simulation using COMSOL with a triangular ring structure for the high permeability soft magnetic tunnel tip of this invention. In the diagram: (1) is the rate of change of magnetic field strength when the detection distance is 0 mm, (2) is the rate of change of magnetic field strength when the detection distance is 0.01 mm, (3) is the rate of change of magnetic field strength when the detection distance is 0.03 mm, and (4) is the rate of change of magnetic field strength when the detection distance is 0.07 mm.

[0032] Figure 14 The high permeability soft magnetic tunnel tip of this invention adopts a rectangular ring structure and is modeled and simulated using COMSOL. The magnetic field strength in the Z-axis direction is changed after changing the ring wall thickness. Among them: (1) is the magnetic field strength when the ring wall thickness is 0.04mm, (2) is the magnetic field strength when the ring wall thickness is 0.03mm, (3) is the magnetic field strength when the ring wall thickness is 0.02mm, and (4) is the magnetic field strength when the ring wall thickness is 0.01mm.

[0033] Figure 15 The diagram shows the rate of change of magnetic field strength after modeling and simulating the high permeability soft magnetic tunnel tip of the present invention using a rectangular ring structure with COMSOL and changing the ring wall thickness. In the diagram: (1) is the rate of change of magnetic field strength when the ring wall thickness is 0.04 mm, (2) is the rate of change of magnetic field strength when the ring wall thickness is 0.03 mm, (3) is the rate of change of magnetic field strength when the ring wall thickness is 0.02 mm, and (4) is the rate of change of magnetic field strength when the ring wall thickness is 0.01 mm.

[0034] Figure 16 The high permeability soft magnetic tunnel tip of this invention adopts a ring structure and is modeled and simulated using COMSOL. The magnetic field strength in the Z-axis direction is changed after changing the ring wall thickness. Among them: (1) is the magnetic field strength when the ring wall thickness is 0.04mm, (2) is the magnetic field strength when the ring wall thickness is 0.03mm, (3) is the magnetic field strength when the ring wall thickness is 0.02mm, and (4) is the magnetic field strength when the ring wall thickness is 0.01mm.

[0035] Figure 17 The high permeability soft magnetic tunnel tip of this invention adopts a ring structure and is modeled and simulated using COMSOL. The magnetic field strength change rate after changing the ring wall thickness is shown in the figure. (1) is the magnetic field strength change rate when the ring wall thickness is 0.04 mm, (2) is the magnetic field strength change rate when the ring wall thickness is 0.03 mm, (3) is the magnetic field strength change rate when the ring wall thickness is 0.02 mm, and (4) is the magnetic field strength change rate when the ring wall thickness is 0.01 mm.

[0036] Figure 18The high permeability soft magnetic tunnel tip of this invention adopts a triangular ring structure and is modeled and simulated using COMSOL. The magnetic field strength in the Z-axis direction is changed after the ring wall thickness is changed. Among them: (1) is the magnetic field strength when the ring wall thickness is 0.04mm, (2) is the magnetic field strength when the ring wall thickness is 0.03mm, (3) is the magnetic field strength when the ring wall thickness is 0.02mm, and (4) is the magnetic field strength when the ring wall thickness is 0.01mm.

[0037] Figure 19 The diagram shows the rate of change of magnetic field strength after modeling and simulating the high permeability soft magnetic tunnel tip of the present invention using a triangular ring structure with COMSOL and changing the ring wall thickness. In the diagram: (1) is the rate of change of magnetic field strength when the ring wall thickness is 0.04 mm, (2) is the rate of change of magnetic field strength when the ring wall thickness is 0.03 mm, (3) is the rate of change of magnetic field strength when the ring wall thickness is 0.02 mm, and (4) is the rate of change of magnetic field strength when the ring wall thickness is 0.01 mm.

[0038] The attached figure includes the following list of reference numerals:

[0039] 1-Magnet under test; 2-Magnet platform; 3-Support frame; 4-Amplification platform; 5-Support groove; 6-High permeability soft magnetic tip; 7-Magnetoresistive resistor; 8-Translation slide; 9-Substrate; 10-Magnetic field light and dark grid assembly. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar originals or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In this invention, it should be explained that the terms "center", "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing and simplifying the description of this invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] In this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] The present invention will be further described below with reference to the accompanying drawings:

[0044] like Figure 1 As shown, a magnetic field light and dark grid device based on magnetic focusing effect includes: a magnet platform 2, a magnetic field light and dark grid assembly 10 and a substrate 9. The magnet platform 2 is disposed on the top of the magnetic field light and dark grid assembly 10 and the substrate 9 is disposed on the bottom of the magnetic field light and dark grid assembly 10.

[0045] The magnetic field light and dark grid assembly 10 includes: a support frame 3, an amplification platform 4, a support groove 5, and a high permeability soft magnetic tunnel tip 6.

[0046] The support groove 5 is slidably disposed within the support frame 3. The support groove 5 is horizontally disposed. Multiple amplification platforms 4 are slidably disposed within the support groove. The amplification platforms 4 can move parallel within the support groove 5 and can change the spacing between the bright and dark grids as needed. The high permeability soft magnetic tip 6 is disposed at the bottom of the amplification platform 4.

[0047] The magnet platform 2 is set on top of the support frame 3. The magnet platform 2 is used to place the magnet to be measured 1. The magnet to be measured 1 is approximately a uniform magnetic field. During measurement, the magnet to be measured 1 is placed on the magnet platform 2.

[0048] The support frame 3 is a rectangular frame with the same size as the plane of the substrate 9, used for fixing and providing a support base.

[0049] The support groove 5 can slide up and down within the support frame 3. The support groove 5 and the support frame 3 can be slidably connected by damping material or damping fit. The distance between the light and dark grid and the magnet 1 under test can be set on the support frame 3 as needed.

[0050] The high-permeability soft magnetic tunnel tip 6 is a ring structure formed by depositing high-permeability material onto a carrier, which can be a silicon wafer. The high-permeability soft magnetic tunnel tip 6 in the magnetic field bright and dark gate can be realized by traditional processes such as PVD, CVD, and electrochemical deposition, or it can be fabricated using high-temperature molten ferrite material through a process similar to metal wire drawing.

[0051] The shape of the high-permeability soft magnetic tip 6 includes, but is not limited to, a rectangular ring, a circular ring, or a triangular ring. The selection of the shape of the high-permeability soft magnetic tip 6 constituting the magnetic field grating is crucial for the magnetic field bright / dark grating. Under the same conditions, rectangular rings, circular rings, and triangular rings, when used as magnetic field bright / dark gratings, exhibit different magnetic focusing effects on the magnetic field. A soft magnetic tip of suitable shape can also be selected as the bright / dark grating according to specific needs.

[0052] The substrate 9 is disposed at the bottom of the support frame 3. A translation slide 8 is provided on the substrate 9. A magnetoresistive 7 is slidably disposed in the translation slide 8. The magnetoresistive 7 can move along the translation slide 8. The magnetoresistive 7 detects the magnetic field change of the magnetic field bright and dark grid assembly 10 by moving.

[0053] In this invention, the most important aspect of the magnetic field bright / dark grid assembly 10 is that the other structures constituting the bright / dark grid structure, except for the high-permeability soft magnetic tunnel tip 6, do not interfere with the measurement of the original magnetic field. Therefore, the materials used to fabricate the magnet platform 2, support frame 3, support groove 5, amplification platform 4, translation slide 8, and substrate 9 can be materials that do not interfere with the magnetic field, such as phenolic plastics, polyurethane plastics, epoxy plastics, unsaturated polyester plastics, furan plastics, silicone resins, and acrylic resins in the plastics category, and copper and platinum in the metals category. The key structure, the high-permeability soft magnetic tunnel tip 6, can be made of materials such as MnZnt ferrite and NiFe alloys. Among them, MnZnt ferrite has advantages such as high density, good hardness, good wear resistance, and grains that are not easily peeled off. Moreover, the permeability of this type of material is usually above 10,000, and some can even reach 100,000, making it an excellent choice for fabricating the high-permeability soft magnetic tunnel tip 6.

[0054] Specifically, such as Figure 3 As shown, a magnetic field bright / dark grating assembly 10 with high permeability is placed in a uniform magnetic field. The influence of the magnetic field bright / dark grating assembly 10 on the uniform magnetic field generates a high-rate-of-change magnetic field. The shape, size, relative permeability, spacing d, distance δ between the high-permeability soft magnetic tunnel tip 6 and the measured magnet 1, and the strength of the uniform magnetic field are all variables affecting the rate of change of the high-rate-of-change magnetic field. Figure 6 Several common shapes for magnetic field bright / dark grating components are given. The appropriate size and relative permeability of the magnetic field bright / dark grating should be selected based on the specific magnetic field variation requirements. Figure 4 As shown, a silicon wafer with a high-permeability soft magnetic tip 6 deposited on it is mounted on the amplification platform 4. The support groove 5 provides a fixing groove for the amplification platform 4 and is connected to the support frame 3. The amplification platforms 4 can be translated on the support groove 5, thereby changing the magnetic field bright and dark grid spacing d as needed. At the same time, the magnitude of the magnetic field change rate can also be changed by controlling the spacing δ between the magnet under test 1 and the high-permeability soft magnetic tip 6 as needed.

[0055] Specifically, when a soft magnetic material with high permeability is placed in a uniform magnetic field, the concentration effect of the soft magnetic material with different shapes on the surrounding magnetic field can amplify a weak magnetic signal by 1-2 orders of magnitude. For example, under the influence of a triangular ring bright and dark grating, the uniform magnetic field exhibits a magnetic field with obvious changes of "low, high, low, high, low, high, low". Through the magnetic concentration effect, a magnetic field strength much higher than the surrounding environment can be obtained near a certain point or line. Then, using this peak value, a higher rate of change of magnetic field can be obtained while keeping the magnetic field environment constant.

[0056] like Figure 7 As shown, the magnetic focusing effect refers to the effect of a high-permeability soft magnetic material on the surrounding magnetic field when placed in a magnetic field domain. In short, the magnetic field strength around a high-permeability material will be much greater than that around the surrounding magnetic field domain. For example... Figure 6 The three different shapes of high-permeability soft magnetic materials shown are placed in a small magnetic field domain. After extracting the magnetic field around the three shapes of high-permeability materials, it was found that the magnetic field at the corners is much higher than that of the surrounding spatial magnetic field domain. Among them, the peak field strength generated by the triangular ring is relatively high, about 9 times the strength of the magnetic field domain. In this embodiment of the invention, since the magnetic field strength is amplified by the high-permeability soft magnetic tunnel tip 6, the strength meets the lower limit requirement of the magnetic sensor range. By measuring the amplification, a stable magnetic field bright / dark grid with a high magnetic field change rate can be obtained.

[0057] like Figure 8 , 9 As shown, COMSOL was used to model and simulate the magnetic field of the rectangular ring of the high permeability soft magnetic tunnel tip 6. The relative permeability of the magnetic field grating, the spacing d between the magnetic field grating and the uniform magnetic field strength were kept constant. The detection distance between the magnetoresistive resistor 7 and the magnetic field grating assembly 10 was changed to obtain the Z-axis component of the magnetic field strength and the magnetic field change rate. Figure 8 In the diagram, (1) represents the magnetic field strength at a detection distance of 0 mm, (2) represents the magnetic field strength at a detection distance of 0.01 mm, (3) represents the magnetic field strength at a detection distance of 0.03 mm, and (4) represents the magnetic field strength at a detection distance of 0.07 mm. Figure 9 (1) is the rate of change of magnetic field strength when the detection distance is 0 mm, (2) is the rate of change of magnetic field strength when the detection distance is 0.01 mm, (3) is the rate of change of magnetic field strength when the detection distance is 0.03 mm, and (4) is the rate of change of magnetic field strength when the detection distance is 0.07 mm. The results show that the magnetic field strength is greater on both sides of the bright and dark grids, and the rate of change of magnetic field is greater. As the detection distance increases, the magnetic field strength decreases, and the rate of change of magnetic field also tends to decrease.

[0058] like Figure 10 , 11As shown, COMSOL was used to model and simulate the magnetic field of the high permeability soft magnetic tunnel tip 6 ring. The relative permeability of the magnetic field grating, the spacing d between the magnetic field grating and the uniform magnetic field strength were kept constant. The detection distance between the magnetoresistive resistor 7 and the magnetic field grating assembly 10 was changed to obtain the Z-axis component of the magnetic field strength and the magnetic field change rate. Figure 10 In the diagram, (1) represents the magnetic field strength at a detection distance of 0 mm, (2) represents the magnetic field strength at a detection distance of 0.01 mm, (3) represents the magnetic field strength at a detection distance of 0.03 mm, and (4) represents the magnetic field strength at a detection distance of 0.07 mm. Figure 11 (1) is the rate of change of magnetic field strength when the detection distance is 0 mm, (2) is the rate of change of magnetic field strength when the detection distance is 0.01 mm, (3) is the rate of change of magnetic field strength when the detection distance is 0.03 mm, and (4) is the rate of change of magnetic field strength when the detection distance is 0.07 mm. The results show that the magnetic field strength is greater on both sides of the bright and dark grids, and the rate of change of magnetic field is greater. As the detection distance increases, the magnetic field strength decreases, and the rate of change of magnetic field also tends to decrease.

[0059] like Figure 12 , 13 As shown, COMSOL was used to model and simulate the magnetic field of the triangular ring of the high permeability soft magnetic tunnel tip 6. The relative permeability of the magnetic field grating, the spacing d between the magnetic field grating and the uniform magnetic field strength were kept constant. The detection distance between the magnetoresistive resistor 7 and the magnetic field grating assembly 10 was changed to obtain the Z-axis component of the magnetic field strength and the magnetic field change rate. Figure 12 In the diagram, (1) represents the magnetic field strength at a detection distance of 0 mm, (2) represents the magnetic field strength at a detection distance of 0.01 mm, (3) represents the magnetic field strength at a detection distance of 0.03 mm, and (4) represents the magnetic field strength at a detection distance of 0.07 mm. Figure 13 (1) is the rate of change of magnetic field strength when the detection distance is 0 mm, (2) is the rate of change of magnetic field strength when the detection distance is 0.01 mm, (3) is the rate of change of magnetic field strength when the detection distance is 0.03 mm, and (4) is the rate of change of magnetic field strength when the detection distance is 0.07 mm. The results show that the magnetic field strength is greater on both sides of the bright and dark grids, and the rate of change of magnetic field is greater. As the detection distance increases, the magnetic field strength decreases, and the rate of change of magnetic field also tends to decrease.

[0060] like Figure 14 , 15 As shown, COMSOL was used to model and simulate the magnetic field of the rectangular ring of the high permeability soft magnetic tunnel tip 6. The relative permeability of the magnetic field grating, the spacing d between the magnetic field gratings, the uniform magnetic field strength, and the detection distance between the magnetoresistor 7 and the magnetic field grating assembly 10 were kept constant. The thickness of the rectangular ring wall was changed to obtain the results of the magnetic field strength component in the Z-axis direction and the magnetic field change rate. Figure 14 In the diagram, (1) represents the magnetic field strength when the ring wall thickness is 0.04 mm, (2) represents the magnetic field strength when the ring wall thickness is 0.03 mm, (3) represents the magnetic field strength when the ring wall thickness is 0.02 mm, and (4) represents the magnetic field strength when the ring wall thickness is 0.01 mm. Figure 15 In the figure, (1) represents the rate of change of magnetic field strength when the ring wall thickness is 0.04 mm, (2) represents the rate of change of magnetic field strength when the ring wall thickness is 0.03 mm, (3) represents the rate of change of magnetic field strength when the ring wall thickness is 0.02 mm, and (4) represents the rate of change of magnetic field strength when the ring wall thickness is 0.01 mm. The results show that the magnetic field strength is greater on both sides of the bright and dark grids, and the rate of change of magnetic field is greater. As the thickness of the rectangular ring wall decreases, the magnetic field strength decreases accordingly, and the rate of change of magnetic field also tends to decrease.

[0061] like Figure 16 , 17 As shown, COMSOL was used to model and simulate the magnetic field of the high permeability soft magnetic tunnel tip 6 ring. Keeping the relative permeability of the magnetic field grating, the spacing d between the magnetic field grating, the uniform magnetic field strength, and the ring wall thickness between the magnetoresistor 7 and the magnetic field grating assembly 10 constant, the ring wall thickness was changed to obtain the magnetic field strength component in the Z-axis direction and the magnetic field change rate. Figure 16 In the diagram, (1) represents the magnetic field strength when the ring wall thickness is 0.04 mm, (2) represents the magnetic field strength when the ring wall thickness is 0.03 mm, (3) represents the magnetic field strength when the ring wall thickness is 0.02 mm, and (4) represents the magnetic field strength when the ring wall thickness is 0.01 mm. Figure 17 In the figure, (1) is the rate of change of magnetic field strength when the ring wall thickness is 0.04 mm, (2) is the rate of change of magnetic field strength when the ring wall thickness is 0.03 mm, (3) is the rate of change of magnetic field strength when the ring wall thickness is 0.02 mm, and (4) is the rate of change of magnetic field strength when the ring wall thickness is 0.01 mm. It can be seen from the results that the magnetic field strength is greater on both sides of the bright and dark grids and the rate of change of magnetic field is greater. As the thickness of the ring wall decreases, the magnetic field strength is reduced and the rate of change of magnetic field also tends to decrease.

[0062] like Figure 18 , 19 As shown, COMSOL was used to model and simulate the magnetic field of the triangular ring of the high permeability soft magnetic tunnel tip 6. The relative permeability of the magnetic field grating, the spacing d between the magnetic field grating and the magnetic field grating, the uniform magnetic field strength, and the ring wall thickness between the magnetoresistor 7 and the magnetic field grating assembly 10 were kept constant. The ring wall thickness of the triangular ring was changed to obtain the component of the magnetic field strength in the Z-axis direction and the results of the magnetic field change rate. Figure 18 In the diagram, (1) represents the magnetic field strength when the ring wall thickness is 0.04 mm, (2) represents the magnetic field strength when the ring wall thickness is 0.03 mm, (3) represents the magnetic field strength when the ring wall thickness is 0.02 mm, and (4) represents the magnetic field strength when the ring wall thickness is 0.01 mm. Figure 19 In the diagram, (1) represents the rate of change of magnetic field strength when the ring wall thickness is 0.04 mm, (2) represents the rate of change of magnetic field strength when the ring wall thickness is 0.03 mm, (3) represents the rate of change of magnetic field strength when the ring wall thickness is 0.02 mm, and (4) represents the rate of change of magnetic field strength when the ring wall thickness is 0.01 mm. The results show that the magnetic field strength and rate of change are greater on both sides of the bright and dark grid. As the thickness of the triangular ring wall decreases, the change in magnetic field strength and rate of change are not significant. Comparing the three shapes of bright and dark grids, it can be seen that the peak field strength and rate of change of magnetic field generated by the triangular ring are higher.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A magnetic field bright / dark grid device based on magnetic focusing effect, characterized in that, include: The magnetic platform (2), the magnetic field light and dark grid assembly (10), and the substrate (9) are provided. The magnetic platform (2) is disposed on the top of the magnetic field light and dark grid assembly (10), and the substrate (9) is disposed on the bottom of the magnetic field light and dark grid assembly (10). The magnetic field light and dark grid assembly (10) includes: a support frame (3), an amplification platform (4), a support groove (5), and a high permeability soft magnetic tunnel tip (6); The support groove (5) is slidably disposed within the support frame (3). The support groove (5) is horizontally disposed. Multiple amplification platforms (4) are slidably disposed within the support groove. The amplification platform (4) has a high permeability soft magnetic tunnel tip (6) at its bottom. The magnet platform (2) is set on top of the support frame (3), and the magnet platform (2) is used to place the magnet (1) to be tested; The support groove (5) and the support frame (3) are slidably connected by damping material or damping fit.

2. The magnetic field bright / dark grid device based on magnetic focusing effect according to claim 1, characterized in that, The high permeability soft magnetic tunnel tip (6) has the following shapes: rectangular ring, circular ring or triangular ring.

3. The magnetic field bright / dark grid device based on magnetic focusing effect according to claim 1, characterized in that, The substrate (9) is disposed at the bottom of the support frame (3), and a translation slide (8) is provided on the substrate (9). A magnetoresistor (7) is slidably disposed in the translation slide (8).

4. The magnetic field bright / dark grid device based on magnetic focusing effect according to claim 1, characterized in that, Therefore, the materials of the magnet platform (2), support frame (3), support groove (5), magnification platform (4), translation slide (8), and substrate (9) are materials that do not interfere with the magnetic field, including: phenolic plastic, polyurethane plastic, epoxy plastic, unsaturated polyester plastic, furan plastic, silicone resin, acrylic resin, copper, and platinum.

5. The magnetic field bright / dark grid device based on magnetic focusing effect according to claim 1, characterized in that, The materials of the high permeability soft magnetic tunnel tip (6) include: MnZnt ferrite and NiFe alloy.

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