Z-axis magnetic field sensor

Abstract

The utility model provides a Z-axis magnetic field sensor. The Z-axis magnetic field sensor comprises a plurality of Z-axis magnetic field conversion structures and a plurality of magnetic resistors. The substrate plane where the Z-axis magnetic field conversion structure is located is an X-Y plane, and the Z-axis magnetic field conversion structure comprises an annular structure on the X-Y plane. And the plurality of magnetic resistors are distributed in an array manner only along the direction parallel to the first group of opposite sides of the Z-axis magnetic field conversion structure. According to the utility model, the magnetic field conversion structure is redesigned to be matched with the corresponding magnetic resistance unit, so that the magnetic field conversion structure plays a role in shielding or suppressing an interference magnetic field while converting a Z-axis magnetic field effect. The Z-axis magnetic field sensor provided by the utility model is ingenious in design, simple in structure, strong in anti-interference capability and high in measurement precision.

Description

Technical Field

[0001] The present application relates to the field of magnetic field measurement technology or magnetic field sensing technology, and in particular to a Z-axis magnetic sensor structure with high conversion efficiency and good anti-interference performance. Background Art

[0002] The Z-axis magnetic field sensor usually uses a magnetic field concentrating structure (or magnetic field conversion structure) made of soft magnetic material (such as NiFe) to convert the magnetic field in the Z-axis direction into a magnetic field in the XY plane. The magnetic field strength in the X-axis or Y-axis direction is measured by sensing the magnetic resistance in the X-axis or Y-axis direction to indirectly obtain the magnetic field strength information in the Z-axis direction.

[0003] However, when the soft magnetic material converts the magnetic field in the Z-axis direction, it will also convert part of the magnetic field in the XY plane that is not in the Z-axis direction (for example, part of the gradient interference magnetic field parallel to the XY plane), thereby causing interference errors in the measurement of the Z-axis magnetic field strength. Existing Z-axis magnetic field sensors usually use magnetic field conversion components and set magnetoresistive units with opposite sensitivity directions on adjacent bridge arms to form a bridge circuit to offset the influence of the interference magnetic field in the XY plane. However, this method is more effective in offsetting constant interference fields parallel to the XY plane, but the suppression effect is not ideal for non-constant interference fields (for example, gradient interference fields parallel to the XY plane). Summary of the Invention

[0004] In view of this, the present invention realizes a Z-axis magnetic field sensor with strong anti-interference ability and high measurement accuracy by redesigning the magnetic field conversion structure and coordinating the corresponding magnetoresistive unit setting; the Z-axis magnetic field sensor can effectively shield / suppress the interfering magnetic field parallel to the XY plane (including non-constant interfering magnetic field).

[0005] In the first part of the embodiments, the Z-axis magnetic field sensor provided by the present invention includes: a plurality of Z-axis magnetic field conversion structures and a plurality of magnetic resistors. The Z-axis magnetic field conversion structure is made of soft magnetic material; the substrate plane where the Z-axis magnetic field conversion structure is located is the XY plane, and the Z-axis magnetic field conversion structure includes a ring structure in the XY plane. The plurality of magnetic resistors are arrayed along a direction parallel to the first set of opposite sides of the Z-axis magnetic field conversion structure, and the two sides of the first set of opposite sides are parallel to each other; the remaining sides of the ring structure are used to shield the interfering magnetic field in the direction of the XY plane. The sensitive directions of the plurality of magnetic resistors are all perpendicular to the first set of opposite sides. Obviously, the remaining sides of the ring structure can shield / suppress the influence of the interfering magnetic field parallel to the XY plane on the magnetic resistors.

[0006] Furthermore, the plurality of magnetic resistors are distributed on the XY plane, on one or both sides of each side of the first set of opposite sides; wherein the sensitive directions of the magnetic resistors on the same side are the same. The magnetic resistors are XMR magnetic resistors, and the XMRs include at least TMR, AMR, and GMR.

[0007] Furthermore, the Z-axis magnetic field conversion structure also includes a plurality of soft magnetic strips arranged inside the annular structure and parallel to the first set of opposite sides. The plurality of magnetic resistors are distributed on one or both sides of each soft magnetic strip on the XY plane, or the plurality of magnetic resistors are distributed on one or both sides of each soft magnetic strip and each side of the first set of opposite sides on the XY plane. For the magnetic resistors arranged inside the annular structure, their interfering magnetic fields parallel to the XY plane will be completely shielded. The plurality of soft magnetic strips and the annular structure, except for the first set of opposite sides, may be connected or not connected.

[0008] Furthermore, the plurality of magnetic resistors are symmetrically distributed on the XY plane on both sides of each soft magnetic strip, or symmetrically distributed on the XY plane on both sides of each soft magnetic strip and each side of the first set of opposite sides. The sensitive directions of the magnetic resistors symmetrically distributed on the XY plane on either side of each soft magnetic strip or each side of the first set of opposite sides are the same.

[0009] Preferably, any two magnetic resistors symmetrically arranged on the XY plane, on both sides of the same soft magnetic strip or any one of the first group of opposite sides, have the same sensitive direction and are respectively located on two adjacent bridge arms of the same Wheatstone bridge (including the same half bridge or different half bridges) or on the two bridge arms of the same half bridge in terms of circuit connection relationship.

[0010] Furthermore, the annular structure is a diamond annular structure or a trapezoidal annular structure. Preferably, the second set of opposite sides of the diamond annular structure is higher than the first set of opposite sides in the Z-axis direction.

[0011] Preferably, the Z-axis magnetic field conversion structure is a square ring structure on the XY plane.

[0012] Preferably, the Z-axis magnetic field sensor further includes a shielding layer provided on the upper side and / or the lower side of the Z-axis magnetic field conversion structure.

[0013] The Z-axis magnetic field sensor provided by this utility model utilizes a unique magnetic field conversion structure designed in conjunction with the layout of the magnetoresistors. This structure not only converts the Z-axis magnetic field but also shields the XY-plane magnetic field from interfering with the magnetoresistors. Combined with the shielding layers on the upper and lower sides of the Z-axis magnetic field sensor and the electrical connection between the magnetoresistors, this relatively simple structure effectively eliminates the effects of interfering magnetic fields on Z-axis magnetic field measurements, thereby improving the measurement accuracy of the Z-axis magnetic field sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0015] Figure 1a This is a schematic structural diagram of the Z-axis magnetic field sensor provided by the present utility model in the first embodiment.

[0016] Figure 1b This is a schematic structural diagram of the Z-axis magnetic field sensor provided by the present invention in the second embodiment.

[0017] Figure 2 This is a schematic structural diagram of the Z-axis magnetic field sensor provided by the present utility model in the third embodiment.

[0018] Figure 3 This is a schematic structural diagram of the Z-axis magnetic field sensor provided by the present utility model in the fourth embodiment. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0020] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0021] The Z-axis magnetic field sensor provided by the first embodiment of the present invention includes: a plurality of Z-axis magnetic field conversion structures and a plurality of magnetic resistors. The Z-axis magnetic field conversion structure is made of soft magnetic material; the substrate plane where the Z-axis magnetic field conversion structure is located is the XY plane, and the Z-axis magnetic field conversion structure includes a ring structure in the XY plane. The plurality of magnetic resistors are arranged in an array along a direction parallel to the first set of opposite sides of the Z-axis magnetic field conversion structure, the two sides of the first set of opposite sides are parallel to each other, and the sensitive direction is perpendicular to the first set of opposite sides. The remaining sides of the ring structure are used to shield the interfering magnetic field in the direction of the XY plane.

[0022] like Figure 1a In the first embodiment shown, the Z-axis magnetic field sensor includes a Z-axis magnetic field conversion structure 10 and a plurality of magnetic resistors 20. The Z-axis magnetic field conversion structure 10 is made of NiFe and has a diamond ring structure ( Figure 1a ( denoted as a square ring structure in the figure). The plurality of magnetic resistors 20 are arranged within the square ring structure and arranged in an array only along a direction parallel to the first set of opposite sides of the square ring structure. The second set of opposite sides of the square ring structure is used to shield interfering magnetic fields parallel to the XY plane. The sensitive directions of the plurality of magnetic resistors 20 are all perpendicular to the first set of opposite sides. Obviously, the sensitive directions of the plurality of magnetic resistors 20 do not necessarily have to be the same; the sensitive directions of some magnetic resistors may be opposite to those of the remaining magnetic resistors.

[0023] like Figure 1b In the second embodiment shown, the Z-axis magnetic field conversion structure 10 is made of NiFe and has a trapezoidal ring structure in the substrate plane (i.e., the XY plane). The plurality of magnetic resistors 20 are disposed within the trapezoidal ring structure 10 and arranged in an array only along a first set of mutually parallel opposite sides of the trapezoidal ring structure.

[0024] exist Figure 1a 、 Figure 1b In the illustrated embodiment, the first set of opposite sides of the Z-axis magnetic field conversion structure 10 is used to convert the Z-axis magnetic field into a magnetic field parallel to the XY plane, which is sensed by the magnetic resistor 20. Furthermore, both the first and second sets of opposite sides can shield interference fields parallel to the XY plane and interference magnetic fields in directions other than the Z-axis, thereby improving the accuracy of the magnetic resistor 20 in detecting the Z-axis magnetic field.

[0025] Furthermore, in addition to being distributed on the XY plane and inside each side of the first set of opposite sides, the plurality of magnetic resistors 20 may also be distributed on both inside and outside sides of each side of the first set of opposite sides.

[0026] Preferably, the sensitive direction of the magnetic resistance on the same side of each side of the first group of opposite sides is the same. The magnetic resistance is XMR magnetic resistance, and the XMR includes at least TMR, AMR, and GMR.

[0027] like Figure 2 In the embodiment shown in FIG. 1 , the plurality of magnetic resistors include magnetic resistors 20 and 21 distributed on both sides of each of the first set of opposite sides. The sensitive directions of magnetic resistors 20 and 21 are the same. The sensitive directions of magnetic resistors 20 and 21 can be the same or opposite. This depends on the connection relationship between magnetic resistors 20 and 21 in the sensing circuit.

[0028] like Figure 3 In the illustrated embodiment, the Z-axis magnetic field conversion structure further includes a plurality of soft magnetic strips 30 disposed within the square annular structure 10 and parallel to the first set of opposite sides. The plurality of soft magnetic strips 30 and the second set of opposite sides of the square annular structure 10 may or may not be connected.

[0029] The plurality of magnetic resistors may be distributed on the XY plane, on one side or both sides of each soft magnetic strip 30, or the plurality of magnetic resistors may be distributed on the XY plane, on one side or both sides of each soft magnetic strip 30 and each side of the first set of opposite sides. Figure 3 As shown, the magnetic resistance is distributed on the XY plane, on each soft magnetic strip 30 and on both sides of each side of the first set of opposite sides. Obviously, for the magnetic resistance set inside the square ring structure 10, its interference magnetic field parallel to the XY plane will be completely shielded.

[0030] Furthermore, the plurality of magnetic resistors are symmetrically distributed on the XY plane, on both sides of each soft magnetic strip 30, or symmetrically distributed on the XY plane, on both sides of each soft magnetic strip 30 and each side of the first set of opposite sides. The magnetic resistors symmetrically distributed on the XY plane, on either side of each soft magnetic strip 30 or each side of the first set of opposite sides have the same sensitive direction. Figure 3 As shown, the magnetic resistors 31 and 32 are distributed on the left and right sides of the soft magnetic strip 30 and are symmetrically arranged with respect to the soft magnetic strip 30. The sensitive directions of the magnetic resistors 31 on one side of the soft magnetic strip 30 are the same, and the sensitive directions of the magnetic resistors 32 on the other side are the same. The sensitive directions of the magnetic resistors 31 and 32 can be the same (e.g. Figure 3 shown), or vice versa.

[0031] Preferably, any two magnetic resistors symmetrically arranged on the XY plane, on both sides of the same soft magnetic strip 30 or any one of the first group of opposite sides have the same sensitive direction, and in the circuit connection relationship are respectively located on two adjacent bridge arms of the same Wheatstone bridge (including the same half bridge or different half bridges), or on the two bridge arms of the same half bridge.

[0032] In order to enable the second set of opposite sides of the Z-axis magnetic field conversion structure to better shield / suppress the influence of the interfering magnetic field parallel to the XY plane but not perpendicular to the sensitive direction of the magnetic resistance on the magnetic resistance, preferably, the second set of opposite sides of the square ring structure 10 is higher than its first set of opposite sides in the Z-axis direction.

[0033] Preferably, the Z-axis magnetic field sensor further includes a shielding layer provided on the upper side and / or the lower side of the Z-axis magnetic field conversion structure.

[0034] In addition, the soft magnetic strips can be continuous or segmented on the XY plane. In addition, the corners of each soft magnetic strip can be rounded.

[0035] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A Z-axis magnetic field sensor, characterized in that: The Z-axis magnetic field sensor includes: a plurality of Z-axis magnetic field conversion structures and a plurality of magnetic resistors; The Z-axis magnetic field conversion structure is made of soft magnetic material; the substrate plane where the Z-axis magnetic field conversion structure is located is the XY plane, and the Z-axis magnetic field conversion structure includes a ring structure in the XY plane; the multiple magnetic resistors are distributed in an array along a direction parallel to the first group of opposite sides of the Z-axis magnetic field conversion structure, the two sides of the first group of opposite sides are parallel to each other, and the sensitive directions of the multiple magnetic resistors are perpendicular to the first group of opposite sides; the remaining sides of the Z-axis magnetic field conversion structure are used to shield the interfering magnetic field in the XY plane direction.

2. The Z-axis magnetic field sensor according to claim 1, wherein: The plurality of magnetic resistors are distributed on the XY plane, on one side or both sides of each side of the first group of opposite sides; wherein the sensitive directions of the magnetic resistors on the same side are the same.

3. The Z-axis magnetic field sensor according to claim 1, wherein: The Z-axis magnetic field conversion structure also includes a plurality of soft magnetic strips arranged inside the annular structure and parallel to the first group of opposite sides; the plurality of magnetic resistances are distributed on the XY plane, on one side or both sides of each soft magnetic strip, or the plurality of magnetic resistances are distributed on the XY plane, on one side or both sides of each soft magnetic strip and each side of the first group of opposite sides.

4. The Z-axis magnetic field sensor according to claim 3, wherein: The plurality of magnetic resistors are symmetrically distributed on the XY plane and on both sides of each soft magnetic strip, or symmetrically distributed on the XY plane and on both sides of each soft magnetic strip and each side of the first set of opposite sides. 5 . The Z-axis magnetic field sensor according to claim 3 , wherein the plurality of soft magnetic strips and the annular structure are connected or not connected at the edges other than the first set of opposite edges.

6. The Z-axis magnetic field sensor according to claim 3, wherein: The sensitive directions of the magnetic resistances on either side of each soft magnetic strip or each side of the first set of opposite sides that are symmetrically distributed on the XY plane are the same.

7. The Z-axis magnetic field sensor according to claim 6, wherein: Any two magnetic resistances symmetrically arranged on the XY plane, on both sides of the same soft magnetic strip or any one of the first set of opposite sides, have the same sensitive direction and are respectively located on two adjacent bridge arms of the same Wheatstone bridge or on two bridge arms of the same half bridge in terms of circuit connection.

8. The Z-axis magnetic field sensor according to claim 7, wherein: The Z-axis magnetic field sensor further includes a shielding layer disposed on an upper side and / or a lower side of the Z-axis magnetic field conversion structure.

9. The Z-axis magnetic field sensor according to any one of claims 1 to 8, wherein: The Z-axis magnetic field conversion structure is a diamond ring structure or a trapezoidal ring structure in the XY plane.

10. The Z-axis magnetic field sensor according to claim 9, wherein: The Z-axis magnetic field conversion structure is a square ring structure in the XY plane.

11. The Z-axis magnetic field sensor according to any one of claims 1 to 8, wherein: The magnetoresistance is XMR magnetoresistance, and the XMR includes at least TMR, AMR, and GMR.

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