A gradient magnetic field detection chip and a magnetic field detection structure

Abstract

An embodiment of the present invention discloses a gradient magnetic field detection chip and a magnetic field detection structure. The gradient magnetic field detection chip includes a wafer substrate; at least one detection array, the detection array includes three magnetoresistive groups, the geometric centers of the three magnetoresistive groups are located on the same straight line and have the same spacing, the magnetoresistive group includes n rows of magnetoresistive segments and each row includes m linearly equidistantly arranged magnetoresistive units, the magnetoresistive segments in the magnetoresistive group are arranged in a stacking fault manner, and the stacking fault displacement length of each magnetoresistive segment is y*c / n, m*n = 35, c is from 0 to n-1, and y is the magnetoresistive unit spacing; the sensitivity directions of the magnetoresistive units are all parallel to the plane of the wafer substrate and all parallel to the extension direction of the detection array, or the sensitivity directions of the magnetoresistive units are all perpendicular to the plane of the wafer substrate; the output signals of the detection array are output in a gradient difference manner; a plurality of lead pads, and the lead pads are connected to the magnetoresistive group through connecting leads. The present invention realizes high-frequency response and high-precision gradient measurement.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of magnetic field gradient measurement, and in particular, to a gradient magnetic field detection chip and a magnetic field detection structure. Background Art

[0002] Measuring the change rate of the magnetic field in space (unit: nT / m or nT / km) is called magnetic field gradient measurement. Magnetic field gradient measurement is used in the aviation field, the surface field, the navigation field, etc.

[0003] Currently, the devices used for high-performance gradient magnetic field measurement include a gear encoder and a magnetic grating ruler. Both have the characteristics of strong anti-interference ability, high reliability, and high sensitivity in the fields of rotation and linear measurement. However, the signal-displacement correlation of the magnetosensitive element itself and the device arrangement are likely to cause high-order harmonic errors, resulting in poor measurement accuracy.

[0004] In application scenarios with high requirements for measurement accuracy, the direct use of current gear encoders and magnetic grating rulers is difficult to meet the accuracy requirements. Summary of the Invention

[0005] The embodiments of the present invention provide a gradient magnetic field detection chip and a magnetic field detection structure to improve the measurement accuracy.

[0006] The embodiments of the present invention provide a gradient magnetic field detection chip, including:

[0007] A wafer substrate;

[0008] At least one detection array, the at least one detection array is disposed on the same side surface of the wafer substrate, the detection array includes three non-overlapping magnetoresistance groups, the geometric centers of the three magnetoresistance groups in the detection array are located on the same straight line and have the same spacing, the magnetoresistance group includes n rows of magnetoresistance segments, the magnetoresistance segment includes m linearly equidistantly arranged magnetoresistance units, the magnetoresistance segments in each magnetoresistance group are arranged in a stacking fault, and the stacking fault displacement length of each magnetoresistance segment is y*c / n, where m and n are both natural numbers and m*n = 35, c is any integer between 0 and n - 1, and y is the spacing between magnetoresistance units in each row of the magnetoresistance segments; the sensitivity directions of the magnetoresistance units are all parallel to the plane of the wafer substrate and all parallel to the extending direction of the detection array, or the sensitivity directions of the magnetoresistance units are all perpendicular to the plane of the wafer substrate; the output signal of the detection array is output in a gradient difference manner;

[0009] A plurality of lead pads, the lead pads and the magnetoresistance group are located on the same side surface of the wafer substrate, and the lead pads are connected to the corresponding magnetoresistance group through connection leads.

[0010] Further, the gradient magnetic field detection chip includes two detection arrays, and the two detection arrays are symmetrically arranged on the wafer substrate, and the symmetry axis is parallel or perpendicular to the extension direction of the detection array.

[0011] Further, it further includes: a packaging shell, and the wafer substrate is located inside the packaging shell.

[0012] Further, the packaging shell is made of a non-magnetic material.

[0013] Further, the surface of the magnetoresistive unit is covered with an insulating material.

[0014] Further, the lead pad is composed of a non-magnetic metal.

[0015] Further, the magnetoresistive unit is a single magnetoresistive element; or,

[0016] The magnetoresistive unit includes a plurality of magnetoresistive elements, and the plurality of magnetoresistive elements form an equivalent magnetoresistance structure through series-parallel connection;

[0017] Wherein, the magnetoresistive element is an anisotropic magnetoresistance, a giant magnetoresistance or a tunneling magnetoresistance.

[0018] Based on the same inventive concept, an embodiment of the present invention further provides a magnetic field detection structure based on a gradient magnetic field detection chip, including:

[0019] The gradient magnetic field detection chip as described above;

[0020] A periodic signal structure, the periodic signal structure includes a plurality of sequentially arranged magnetic field response units, and each of the magnetic field response units generates a set of periodic magnetic field signals whose relative position with the gradient magnetic field detection chip changes at the position of the gradient magnetic field detection chip, and the geometric center distance between two spaced magnetic field response units is three times the geometric center distance between adjacent magnetoresistance groups in the detection array.

[0021] Further, the periodic signal structure is a multi-pole magnetic grating, and the poles in the multi-pole magnetic grating are arranged along the extension direction of the detection array; or, the periodic signal structure is a multi-pole magnetic ring, and the poles in the multi-pole magnetic ring are arranged along the circumferential direction of the magnetic ring;

[0022] Wherein, the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the pole arrangement direction.

[0023] Further, it further includes: a back magnetic structure;

[0024] The periodic signal structure is composed of a rack or a gear containing a magnetic material. The gradient magnetic field detection chip is located between the back magnetic structure and the periodic signal structure, and the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the extending direction of the rack or the arranging direction of the gears.

[0025] When there is no such periodic signal structure, the direction of the magnetic induction line of the back magnetic structure at the magnetoresistive unit is perpendicular to the sensitivity direction of the magnetoresistive unit.

[0026] In the embodiment of the present invention, the gradient magnetic field detection chip using magnetoresistance as the sensitive material includes at least one detection array. The detection array includes a three-phase multi-stage stacking misaligned wiring array magnetoresistive group. Through the spatial arrangement of the magnetoresistive units in the magnetoresistive group, by using the phase and amplitude differences of the original output signals of each magnetoresistive segment in the stacking fault structure for the gradient magnetic field in the target interval, the specific high-order harmonic errors under the periodic phase are mutually cancelled, the intrinsic harmonic error of the magnetoresistance and the harmonic error of the device arrangement are eliminated, the detection accuracy of the pole signal is effectively improved, and the detection accuracy of the gradient magnetic field is effectively improved. At the same time, by using the high sensitivity, fast response speed and low power consumption characteristics of the magnetoresistance as the sensitive element, the measurement error caused by high-order harmonics in the conventional gradient magnetic field detection chip is solved, which is beneficial to the high-precision detection of linear displacement and gear encoders, and can simultaneously achieve high-performance gradient measurement accuracy and high-frequency response. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some specific embodiments of the present invention. For those skilled in the art, according to the basic concepts of the device structure, driving method and manufacturing method disclosed and prompted by various embodiments of the present invention, they can be extended and extended to other structures and drawings. Undoubtedly, these should be within the scope of the claims of the present invention.

[0028] Figure 1 It is a schematic diagram of a gradient magnetic field detection chip provided by an embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the arrangement of the magnetoresistive units of a single linear array magnetoresistive group;

[0030] Figure 3 It is another schematic diagram of the arrangement of the magnetoresistive units of a single linear array magnetoresistive group;

[0031] Figure 4 It is a schematic diagram of another gradient magnetic field detection chip provided by an embodiment of the present invention;

[0032] Figure 5 It is a schematic diagram of yet another gradient magnetic field detection chip provided by an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of a single magnetoresistive unit;

[0034] Figure 7 is a cross-sectional view of a gradient magnetic field detection chip provided by an embodiment of the present invention;

[0035] Figure 8 is a schematic diagram of the relative position of a single detection array in cooperation with a multi-pole magnetic grating;

[0036] Figure 9 is a schematic diagram of the relative position of a single detection array in cooperation with a rack;

[0037] Figure 10 is a schematic diagram of the magnetic induction lines of the back magnetic structure perpendicular to the wafer substrate without a periodic signal structure;

[0038] Figure 11 is a schematic diagram of the magnetic induction lines of the back magnetic structure parallel to the wafer substrate without a periodic signal structure;

[0039] Figure 12 is a schematic diagram of the distribution of the magnetic induction lines of the back magnetic structure with the rack parallel to the wafer substrate;

[0040] Figure 13 is a schematic diagram of the relative position of a multi-pole magnetic grating and a gradient magnetic field detection chip. Detailed implementation manners

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will, with reference to the accompanying drawings in the embodiments of the present invention, clearly and completely describe the technical solutions of the present invention through implementation manners. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the basic concepts disclosed and prompted by the embodiments in the present invention, all other embodiments obtained by those skilled in the art fall within the scope of protection of the present invention.

[0042] Reference Figure 1As shown in the figure, it is a schematic diagram of a gradient magnetic field detection chip provided by an embodiment of the present invention. The gradient magnetic field detection chip provided by this embodiment includes: a wafer substrate 301; at least one detection array 100, and at least one detection array 100 is arranged on the same side surface of the wafer substrate 301. The detection array 100 includes three non-overlapping magnetoresistive groups 105. The geometric centers of the three magnetoresistive groups 105 in the detection array 100 are located on the same straight line and have the same spacing. The magnetoresistive group 105 includes n rows of magnetoresistive segments 101, and the magnetoresistive segment 101 includes m linearly equidistantly arranged magnetoresistive units 102. The magnetoresistive segments 101 in the magnetoresistive group 105 are arranged in a stacking fault, and the stacking fault displacement length 103 of each magnetoresistive segment 101 is y*c / n, where m and n are both natural numbers and m*n = 35, c is any integer between 0 and n - 1, and y is the spacing 104 between the magnetoresistive units 102 in each row of magnetoresistive segments 101; the sensitivity directions of the magnetoresistive units 102 are all parallel to the plane of the wafer substrate 301 and all parallel to the extension direction of the detection array 100, or the sensitivity directions of the magnetoresistive units 102 are all perpendicular to the plane of the wafer substrate 301; the output signals of the detection array 100 are output in a gradient difference manner; a plurality of lead pads 302, the lead pads 302 and the magnetoresistive group 105 are located on the same side surface of the wafer substrate 301, and the lead pads 302 are connected to the corresponding magnetoresistive group 105 through connection leads 303. As Figure 2 Shown is a kind of magnetoresistive group, as Figure 3 Shown is another kind of magnetoresistive group.

[0043] In this embodiment, as Figure 1 Shown, the gradient magnetic field detection chip includes one detection array 100 located on the wafer substrate 301. In other embodiments, it is also optional that the gradient magnetic field detection chip includes a plurality of detection arrays located on the wafer substrate and the plurality of detection arrays are arranged on the same side surface of the wafer substrate.

[0044] The detection array 100 includes three non-overlapping magnetoresistive groups 105. The same three magnetoresistive groups 105 are arranged on the same side surface of the wafer substrate 301. Herein, the non-overlapping means that the three magnetoresistive groups 105 are arranged in sequence along a certain direction (such as the X direction shown in the figure) on one surface of the wafer substrate 301, and there is a gap 100a between adjacent two magnetoresistive groups 105 along their arrangement direction. The geometric centers of the three magnetoresistive groups 105 in the detection array 100 are located on the same straight line, then the arrangement direction X of the magnetoresistive group 105 is parallel to this straight line, there is a gap 100a between adjacent two magnetoresistive groups 105 along their arrangement direction and the size of this gap is the same, and the geometric center spacing 100b of the three magnetoresistive groups 105 is the same, that is, the geometric center spacing 100b between any adjacent two magnetoresistive groups 105 is of the same size.

[0045] In this embodiment, the magnetoresistive groups 105 in the detection array 100 are linear magnetoresistive groups. Each linear magnetoresistive group 105 includes 35 magnetoresistive units 102 and is divided into multiple rows of magnetoresistive segments 101. The arrangement of the magnetoresistive units 102 in each row of magnetoresistive segments 101 is exactly the same. The m magnetoresistive units 102 in each row of magnetoresistive segments 101 are located on the same straight line. The geometric centers of the three magnetoresistive groups 105 are located on the same straight line. Optionally, the extending direction of each row of magnetoresistive segments 101 is the same as the arrangement direction X of the three magnetoresistive groups 105 in the detection array 100.

[0046] As Figure 2 shown, there is a magnetoresistive group 105. Optionally, m = 7 and n = 5. Specifically, this magnetoresistive group 105 includes 5 rows of magnetoresistive segments 101. Each row of magnetoresistive segments 101 includes 7 magnetoresistive units 102. Among them, the 7 magnetoresistive units 102 in each row of magnetoresistive segments 101 are arranged along the first direction X, that is, linearly arranged, and the spacing 104 between any two adjacent magnetoresistive units 102 in each row is the same value, that is, equidistantly arranged. The magnetoresistive segments 101 in the magnetoresistive group 105 are arranged in a stacking fault, that is, the relative positions between different rows of magnetoresistive segments 101 are arranged in a stacking fault shape. Simply understood, there is a stacking fault displacement at the starting positions of different rows of magnetoresistive segments 101. The stacking fault displacement length 103 of each magnetoresistive segment 101 is y*c / 5. Optionally, the displacement amount 103 at the starting positions of each magnetoresistive segment 101 is y*c / 5.

[0047] c takes any mutually exclusive integer between 0 and 4, and y is the spacing 104 between the magnetoresistive units 102 in each row of magnetoresistive segments 101. For example, if c is 2 and y is 10 nm, then the stacking fault displacement length 103 is 4 nm. As Figure 2 shown, if the starting position of the fifth row of magnetoresistive segments 101 is set as the 0 nm point, then optionally, the starting position of the third row of magnetoresistive segments 101 is 4 nm, the starting position of the fourth row of magnetoresistive segments 101 is 8 nm, the starting position of the first row of magnetoresistive segments 101 is 12 nm, and the starting position of the second row of magnetoresistive segments 101 is 16 nm.

[0048] As Figure 3 shown, there is another magnetoresistive group 105. Optionally, m = 5 and n = 7. Specifically, this magnetoresistive group 105 includes 7 rows of magnetoresistive segments 101. Each row of magnetoresistive segments 101 includes 5 magnetoresistive units 102. Among them, the 5 magnetoresistive units 102 in each row of magnetoresistive segments 101 are arranged along the first direction X, and the spacing 104 between any two adjacent magnetoresistive units 102 in a row is the same. The magnetoresistive segments 101 in the magnetoresistive group 105 are arranged in a stacking fault, and the stacking fault displacement length 103 of each magnetoresistive segment 101 is y*c / 7.

[0049] c takes any mutually exclusive integer between 0 and 6, and y is the spacing 104 between the magnetoresistive units 102 in each row of magnetoresistive segments 101. For example, if c is 3 and y is 14 nm, then the stacking fault displacement length 103 is 6 nm. AsFigure 3 As shown, if the starting position of the magnetoresistive segment 101 in the 6th row is set at the 0 nm point, then the starting position of the magnetoresistive segment 101 in the 4th row can be selected as 6 nm, the starting position of the magnetoresistive segment 101 in the 5th row as 12 nm, the starting position of the magnetoresistive segment 101 in the 2nd row as 18 nm, the starting position of the magnetoresistive segment 101 in the 3rd row as 24 nm, the starting position of the magnetoresistive segment 101 in the 1st row as 30 nm, and the starting position of the magnetoresistive segment 101 in the 7th row as 36 nm.

[0050] It can be understood that Figure 2 and Figure 3 the fault-like arrangement structure of the magnetoresistive groups in [description] is only a specific example, and other fault-like arrangement methods can also be adopted in other embodiments, not limited to this.

[0051] For any magnetoresistive unit 102, it is optional that its sensitivity direction is parallel to the plane of the wafer substrate 301, and its sensitivity direction is also parallel to the extension direction of the detection array 100. Among them, the extension direction of the detection array 100 is the arrangement direction of the three magnetoresistive groups 105 in the detection array 100, that is, the X direction. In other embodiments, it is also optional that the sensitivity direction of each magnetoresistive unit is perpendicular to the plane of the wafer substrate.

[0052] In this embodiment, a plurality of lead pads 302 are further provided on the surface of the wafer substrate 301. The lead pads 302 and the detection array 100 are located on the same side surface of the wafer substrate 301. One magnetoresistive group 105 is correspondingly arranged with two lead pads 302. One magnetoresistive group 105 is electrically connected to the corresponding two lead pads 302 through two connection leads 303 respectively. The signals of the 3 magnetoresistive groups 105 in the detection array 100 are output independently. The output signals of the detection array 100 are output in a gradient difference manner. Specifically, the external circuit is connected to the two lead pads 302 corresponding to each magnetoresistive group 105, then the output signals of each magnetoresistive group 105 in the detection array 100 are output to the external circuit through the corresponding connection leads 303 and lead pads 302. Among them, the magnetoresistive segments 101 inside the magnetoresistive group 105 are connected in series.

[0053] In other embodiments, it is also optional that the gradient magnetic field detection chip includes two detection arrays, and the two detection arrays are symmetrically arranged on the wafer substrate, and the symmetry axis is parallel or perpendicular to the extension direction of the detection array.

[0054] Such as Figure 4 shown, the symmetry axis is parallel to the extension direction X of the detection array 100. Each detection array 100 is correspondingly provided with 6 lead pads 302. The connecting lines of the geometric centers of the magnetoresistive groups of the two detection arrays 100 are parallel. The distance between the geometric center of the central magnetoresistive group and the geometric centers of the magnetoresistive groups on both sides in a single detection array 100 (same as Figure 1is equal to that in 100b), and the line connecting the geometric centers of two central magnetoresistive groups in different detection arrays 100 is perpendicular to the line where the geometric centers of three linear magnetoresistive groups in a single detection array 100 are located.

[0055] As Figure 5 shown, the symmetry axis is perpendicular to the extension direction X of the detection array 100. Six lead pads 302 are correspondingly arranged for each detection array 100. The geometric centers of six magnetoresistive groups of two detection arrays 100 are located on the same straight line, and the distance between the geometric centers of any two adjacent magnetoresistive groups (the same as Figure 1 that in 100b)) is equal. The resistors of each magnetoresistive segment inside the magnetoresistive group are connected in series, so that the magnetoresistive groups at corresponding positions of two detection arrays 100 form a half-bridge differential output signal, thereby improving the signal strength.

[0056] The optional magnetoresistive unit 102 is a single magnetoresistive element; wherein, the magnetoresistive element is anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance. In this embodiment, each magnetoresistive unit 102 is composed of a single magnetoresistive element, that is, a magnetoresistive unit 102 is a magnetoresistive element, and the magnetoresistive element is anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance. It can be understood that each magnetoresistive unit 102 in a gradient magnetic field detection chip is exactly the same. For example, each magnetoresistive unit 102 is composed of a single giant magnetoresistive element.

[0057] In other embodiments, as Figure 6 shown, the optional magnetoresistive unit 102 further includes a plurality of magnetoresistive elements 102a, and the plurality of magnetoresistive elements 102a form an equivalent magnetoresistive structure 102 through series-parallel connection; wherein, the magnetoresistive element 102a is anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance. It can be understood that each magnetoresistive unit 102 in a gradient magnetic field detection chip is exactly the same. For example, each magnetoresistive unit 102 is composed of 12 tunneling magnetoresistive elements 102a. For any one magnetoresistive unit 102, the 12 tunneling magnetoresistive elements 102a are arranged in 3 rows and 4 columns. Four tunneling magnetoresistive elements 102a in one row are connected in series to form a tunneling magnetoresistive element string, and 3 tunneling magnetoresistive element strings are connected in parallel to form an equivalent magnetoresistive structure 102.

[0058] In an embodiment of the present invention, a gradient magnetic field detection chip using magnetoresistance as a sensitive material includes at least one detection array. The detection array includes a three-phase multi-level stacking dislocation wiring column magnetoresistance group. Through the spatial arrangement of magnetoresistance units in the magnetoresistance group, by using the phase and amplitude differences of the original output signals of each magnetoresistance segment in the stacking dislocation structure for the gradient magnetic field in the target interval, the specific high-order harmonic errors under the periodic phase are mutually cancelled, the magnetoresistance intrinsic harmonic error and the device arrangement harmonic error are eliminated, the detection accuracy of the opposite-pole signal is effectively improved, and the gradient magnetic field detection accuracy is effectively improved. At the same time, by using the high sensitivity, fast response speed and low power consumption characteristics of the magnetoresistance as a sensitive element, the measurement error caused by high-order harmonics in the conventional gradient magnetic field detection chip is solved, which is beneficial to the high-precision detection of linear displacement and gear encoders, and can simultaneously achieve high-performance gradient measurement accuracy and high-frequency response.

[0059] Optionally, as Figure 7 shown, the gradient magnetic field detection chip further includes: a packaging shell 305, and a wafer substrate 301 is located inside the packaging shell 305. Optionally, the packaging shell 305 is made of a non-magnetic material. Optionally, the surface of the magnetoresistance unit 102 is covered with an insulating material 304. Optionally, the lead pad 302 is made of a non-magnetic metal.

[0060] In this embodiment, the gradient magnetic field detection chip is provided with a packaging shell 305 made of a non-magnetic material, which is used to package the wafer substrate 301 and the magnetoresistance structure thereon, can protect the structural performance of the gradient magnetic field detection chip, and can also avoid introducing additional magnetic field interference.

[0061] The wafer substrate 301 is arranged inside the packaging shell 305, and both the magnetoresistance unit 102 and the lead pad 302 are located on the surface of the wafer substrate 301. The surface of the magnetoresistance unit 102 is covered with an insulating material 304, which can protect the electrical performance of the gradient magnetic field detection chip, prevent external moisture and other impurities from entering the magnetoresistance unit 102, extend the life of the magnetoresistance unit 102, and ensure the electrical performance of the magnetoresistance unit 102. The lead pad 302 is made of a non-magnetic metal, so that the lead pad 302 is not interfered by an external magnetic field when transmitting a signal, ensuring the accuracy of signal transmission; the lead pad 302 is made of a non-magnetic metal, so that no additional magnetic field interference is introduced, improving the detection accuracy of the gradient magnetic field detection chip.

[0062] Based on the same inventive concept, an embodiment of the present invention further provides a magnetic field detection structure based on a gradient magnetic field detection chip. The magnetic field detection structure includes: the gradient magnetic field detection chip as described in any of the above embodiments; a periodic signal structure, which includes a plurality of sequentially arranged magnetic field response units. Each magnetic field response unit generates a set of periodic magnetic field signals whose relative position with the gradient magnetic field detection chip changes at the position of the gradient magnetic field detection chip. The geometric center distance between two spaced magnetic field response units is three times the geometric center distance between adjacent magnetoresistive groups in the detection array.

[0063] Optionally, the periodic signal structure is a multi-pole magnetic grating, and the poles in the multi-pole magnetic grating are arranged along the extending direction of the detection array; alternatively, the periodic signal structure is a multi-pole magnetic ring, and the poles in the multi-pole magnetic ring are arranged along the circumferential direction of the magnetic ring; wherein, the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the pole arrangement direction.

[0064] As Figure 8 shown, the periodic signal structure is a multi-pole magnetic grating, and the poles in the multi-pole magnetic grating are arranged along the extending direction X of the detection array; wherein, the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the pole arrangement direction X. The multi-pole magnetic grating is composed of a plurality of N poles and a plurality of S poles arranged at intervals, and is arranged in a straight line. An adjacent N pole and an S pole form a pair of poles. Among them, 202 represents a magnetic pole in the multi-pole magnetic grating, and each pair of poles is arranged along the extending direction X of the detection array. It can be understood that a magnetic pole 202 is correspondingly arranged with a linear magnetoresistive group 105, and they cooperate to form a gradient magnetic field detection structure. The arrangement direction X of the three linear magnetoresistive groups 105 in the detection array is the same as the pole arrangement direction. If the geometric center distance 106 between adjacent magnetoresistive groups 105 is x, then the geometric center distance 202a between adjacent like magnetic poles 202 cooperating with it is 3x. Through the multi-level staggered spatial arrangement of the magnetoresistive unit, the magnetoresistive segment and the magnetoresistive group 105, a phase change of the signal detection position relative to the magnetic field to be detected is formed, and the corresponding harmonic error can be eliminated.

[0065] In other embodiments, it is also optional that the periodic signal structure is a multi-pole magnetic ring, and the poles in the multi-pole magnetic ring are arranged along the circumferential direction of the magnetic ring; wherein, the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the pole arrangement direction. Different from Figure 8 this, in this embodiment, the multi-pole magnetic ring is annular, that is, a plurality of N poles and a plurality of S poles are arranged at intervals in the circumferential direction.

[0066] In other embodiments, it is also optional that as Figure 9The shown periodic signal structure is composed of a rack 201 containing magnetic material. The rack 201 includes tooth peaks and tooth valleys arranged at intervals along a straight line. The tooth peaks and the linear magnetoresistive element groups 105 form a gradient magnetic field detection structure. The tooth valley adjacent to the tooth peak also forms a gradient magnetic field detection structure with the next linear magnetoresistive element group 105. Three linear magnetoresistive element groups 105 in the detection array are arranged in a straight line along the extension direction X of the rack 201. If the geometric center distance 106 between adjacent magnetoresistive element groups 105 is set as x, then the geometric center distance 201a between two adjacent tooth peaks in cooperation therewith is 3x.

[0067] In other embodiments, the periodic signal structure can also be optionally composed of a gear containing magnetic material. The gear includes tooth peaks and tooth valleys arranged at intervals along the circumference, that is, the gear is annular.

[0068] The optional magnetic field detection structure further includes: a back magnetic structure; the periodic signal structure is composed of a rack or a gear containing magnetic material, the gradient magnetic field detection chip is located between the back magnetic structure and the periodic signal structure, and the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the extension direction of the rack or the arrangement direction of the gear; when there is no periodic signal structure, the magnetic induction line direction of the back magnetic structure at the magnetoresistive unit is perpendicular to the sensitivity direction of the magnetoresistive unit.

[0069] As Figure 10 shown, in the linear magnetoresistive element groups in the gradient magnetic field detection chip 300, the sensitivity directions 306 of each magnetoresistive unit 102 are the same and parallel to the arrangement direction of the linear magnetoresistive element groups (such as Figure 1 the X direction in the figure), and this direction is also used as the sensitive direction of the gradient magnetic field detection chip 300. A back magnetic structure 204 is provided in the gradient magnetic field detection structure, and the gradient magnetic field detection chip 300 is located between the back magnetic structure 204 and the periodic signal structure (not shown). Figure 10 In the case of no periodic signal structure in the shown magnetic field detection structure, the magnetic induction line direction 203 generated by the back magnetic structure 204 at the magnetoresistive unit 102 is perpendicular to the plane where the gradient magnetic field detection chip 300 is located and perpendicular to the sensitive direction 306 of the gradient magnetic field detection chip 300.

[0070] As Figure 11 shown, in the case of no periodic signal structure in the magnetic field detection structure, the magnetic induction line direction 203 of the back magnetic structure 204 at the position of the magnetoresistive unit 102 is parallel to the plane where the gradient magnetic field detection chip, that is, the wafer substrate 301, is located, ensuring that in the displacement measurement environment along a linear line (such as Figure 1 the straight line represented by the X direction in the figure), the relative change in the equivalent sensitivity of each magnetoresistive unit 102 parallel to the surface of the wafer substrate 301 is consistent.

[0071] As Figure 12As shown, in the case where there is a periodic signal structure in the magnetic field detection structure, the rack 201 is set as the periodic signal structure, and the gradient magnetic field detection chip 300 is located between the rack 201 and the back magnetic structure 204. The rack 201 contains ferromagnetic materials. When the tooth crest in the rack 201 approaches the gradient magnetic field detection chip 300, it causes the direction of the magnetic induction line 203 to shift towards the tooth crest direction. The magnetic field intensity of the magnetoresistance group 105 close to the tooth crest increases, and the magnetic field intensity of the magnetoresistance group 105 close to the tooth groove, i.e., the tooth valley position, decreases. Thus, different phases with the same change period of the magnetic field intensity at the positions of different magnetoresistance groups arranged in a straight line are realized, and the phase differences are equal.

[0072] As Figure 13 shown, in the case where there is a periodic signal structure in the magnetic field detection structure, multiple pair of pole magnetic gratings 202 are set as the periodic signal structure. The plane where the gradient magnetic field detection chip, i.e., the wafer substrate 301, is located is parallel to the plane where the magnetic grating 202 is located. The gradient magnetic field detection chip includes two detection arrays, which are respectively arranged at both ends of the same surface of the wafer substrate 301. Each detection array includes three linear magnetoresistance groups, and each linear magnetoresistance group includes 35 magnetoresistance units 102. The gradient magnetic field detection chip is provided with multiple lead pads 302, and each magnetoresistance group is connected to the lead pad 302 through a connecting lead 303. The geometric centers of the three linear magnetoresistance groups of each detection array are located on the same straight line, and this straight line is parallel to the pole arrangement direction of the magnetic grating 202. The connecting lines of the geometric centers of the three linear magnetoresistance groups of the two detection arrays are parallel, and the distances between the geometric center of the central magnetoresistance group and the geometric centers of the magnetoresistance groups on both sides are equal. The connecting line of the geometric centers of the two central magnetoresistance groups is perpendicular to the straight line where the geometric centers of the three linear magnetoresistance groups in a single detection array are located. The two central magnetoresistance groups correspond to both ends of the same magnetic pole of the magnetic grating.

[0073] A gradient magnetic field detection structure for detecting a gradient magnetic field provided by an embodiment of the present invention is composed of a three-phase stacking fault arrangement of magnetoresistors. By using the phase and amplitude differences of the original output signals of each section of magnetoresistors in the stacking fault structure for the gradient magnetic field in the target interval, the errors caused by the intrinsic harmonics of the magnetoresistors and the errors caused by the device arrangement harmonics are eliminated, effectively improving the rotation and linear gradient measurement accuracies, and also effectively improving the position and angle detection accuracies. At the same time, by using the high sensitivity and low power consumption characteristics of the magnetoresistor as a sensitive element, the measurement errors caused by high-order harmonics in the previous detection structure are solved, which is beneficial to the high-precision detection of linear displacement and gear encoders.

[0074] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, re-adjustments, combinations with each other and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A gradient magnetic field detection chip, characterized in that Comprising: A wafer substrate; At least one detection array, the at least one detection array being disposed on the same side surface of the wafer substrate, the detection array including three non-overlapping magnetoresistive groups, the geometric centers of the three magnetoresistive groups in the detection array being located on the same straight line and having the same spacing, each magnetoresistive group including n rows of magnetoresistive segments, each magnetoresistive segment including m linearly equidistantly arranged magnetoresistive units, the magnetoresistive segments in each magnetoresistive group being arranged in a stacking fault manner, and the stacking fault displacement length of each magnetoresistive segment being y*c / n, where m and n are both natural numbers and m*n = 35, c is any integer between 0 and n-1, and y is the spacing between magnetoresistive units in each row of magnetoresistive segments; the sensitivity directions of the magnetoresistive units are all parallel to the plane of the wafer substrate and all parallel to the extending direction of the detection array, or the sensitivity directions of the magnetoresistive units are all perpendicular to the plane of the wafer substrate; the output signal of the detection array is output in a gradient difference manner; A plurality of lead pads, the lead pads and the magnetoresistive groups being located on the same side surface of the wafer substrate, and the lead pads being connected to the corresponding magnetoresistive groups through connection leads.

2. The gradient magnetic field detection chip according to claim 1, wherein The gradient magnetic field detection chip includes two detection arrays, and the two detection arrays are symmetrically disposed on the wafer substrate, and the symmetry axis is parallel or perpendicular to the extending direction of the detection array.

3. The gradient magnetic field detection chip according to claim 1, characterized in that, Further comprising: A packaging housing, and the wafer substrate is located inside the packaging housing.

4. The gradient magnetic field detection chip according to claim 3, characterized in that The packaging housing is made of a non-magnetic material.

5. The gradient magnetic field detection chip according to claim 1, wherein The surface of the magnetoresistive unit is covered with an insulating material.

6. The gradient magnetic field detection chip according to claim 1, characterized in that The lead pads are composed of non-magnetic metals.

7. The gradient magnetic field detection chip according to claim 1, characterized in that The magnetoresistive unit is a single magnetoresistive element; or, The magnetoresistive unit includes a plurality of magnetoresistive elements, and the plurality of magnetoresistive elements form an equivalent magnetoresistive structure through series-parallel connection; Wherein, the magnetoresistive element is anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance.

8. A magnetic field detection structure based on a gradient magnetic field detection chip, characterized in that, Comprising: The gradient magnetic field detection chip according to any one of claims 1 to 7; A periodic signal structure, the periodic signal structure including a plurality of sequentially arranged magnetic field response units, each magnetic field response unit generating a set of periodic magnetic field signals whose relative position with respect to the gradient magnetic field detection chip changes at the position of the gradient magnetic field detection chip, and the geometric center spacing between two spaced magnetic field response units is three times the geometric center spacing between adjacent magnetoresistive groups in the detection array.

9. According to the magnetic field detection structure of claim 8, wherein The periodic signal structure is a multi-pole magnetic grating, and the poles in the multi-pole magnetic grating are arranged along the extending direction of the detection array; or, the periodic signal structure is a multi-pole magnetic ring, and the poles in the multi-pole magnetic ring are arranged along the circumferential direction of the magnetic ring; Wherein, the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the pole arrangement direction.

10. The magnetic field detection structure according to claim 8, wherein, Further comprising: A back magnetic structure; The periodic signal structure is composed of a rack or gear containing a magnetic material, the gradient magnetic field detection chip is located between the back magnetic structure and the periodic signal structure, and the sensitivity direction of the magnetoresistive unit is perpendicular or parallel to the extending direction of the rack or the arrangement direction of the gear; In the absence of the periodic signal structure, the direction of the magnetic induction lines of the back magnetic structure at the magnetoresistive unit is perpendicular to the sensitivity direction of the magnetoresistive unit.

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