Magnetoresistive element, angle sensor and electronic equipment

Abstract

The invention relates to the technical field of angle measurement, and discloses a magnetoresistive element, an angle sensor and electronic equipment. The magnetoresistive element comprises a plurality of magnetoresistive sub-elements, and the magnetoresistive sub-elements are used for inducing in-plane magnetic field components acting on the magnetoresistive sub-elements in a magnetic field generated by the magnetic field source and outputting a linearly changing first signal in response to the in-plane magnetic field components within a preset magnetic field range; the magnetoresistive sub-element comprises a plurality of magnetic tunnel junctions, and sensing layers in the magnetic tunnel junctions are provided with closed vortex magnetization patterns; and the plurality of magnetic orbital transfer elements are positioned around the magnetic resistance sub-elements and are used for adjusting the magnetic field distribution of the magnetic field generated by the magnetic field source around the magnetic resistance sub-elements, so that the first signal is related to the rotation angle of the magnetic field source. The magnetoresistive element can measure the angle information of the magnetic field source in a linear interval, avoids the problem that a strong magnetic field generated by the magnetic field source causes fine offset of the reference layer and further affects the angle measurement precision, and has the advantages of being simple in structure and easy to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of rotation angle measurement, and in particular to a magnetoresistive element, an angle sensor and an electronic device. Background Art

[0002] When spin valve magnetoresistive angle sensing units such as TMR or GMR are in normal use, the magnetic moment of the reference layer does not change with the direction of the external magnetic field, and the value of the external magnetic field must be much larger than the saturation magnetic field of the free layer so that the magnetic moment of the free layer is consistent with the direction of the external magnetic field.

[0003] However, in actual measurements, an excessively high external magnetic field often causes a slight offset in the magnetic moment of the reference layer in the magnetoresistive angle sensor unit, resulting in low angle measurement accuracy. Summary of the Invention

[0004] The purpose of the present invention is to provide a magnetoresistive element, an angle sensor and an electronic device to improve the problem of low angle measurement accuracy caused by slight deviation of the magnetic moment of the reference layer in the existing magnetoresistive angle sensor unit due to the external magnetic field.

[0005] A first aspect of the present invention provides a magnetoresistive element, comprising: A plurality of magnetoresistive sub-elements, each configured to sense an in-plane magnetic field component acting on each magnetoresistive sub-element in a magnetic field generated by a magnetic field source, and output a linearly varying first signal within a preset magnetic field range in response to the in-plane magnetic field component; wherein the magnetoresistive sub-elements include a plurality of magnetic tunnel junctions, each having a sensing layer having a closed vortex magnetization pattern; A plurality of magnetic track changing elements are located around each of the magnetic resistance sub-elements and are used to adjust the magnetic field distribution of the magnetic field generated by the magnetic field source around each of the magnetic resistance sub-elements so that the first signal is correlated with the rotation angle of the magnetic field source.

[0006] According to some embodiments of the present invention, the distance between the magnetoresistive element and the magnetic field source is greater than a first distance, so that the in-plane magnetic field component induced by the magnetoresistive element is smaller than the saturation magnetic field of the magnetoresistive element.

[0007] According to some embodiments of the present invention, the magnetoresistive element is located at an eccentric position above or below the magnetic field source, deviating from a central position of the magnetic field source.

[0008] According to some embodiments of the present invention, the magnetic track changing element can converge the magnetic field component acting on the magnetic resistance element that is parallel to the magnetic sensitive direction of the magnetic resistance element, while reducing the magnetic field component acting on the magnetic resistance element that is orthogonal to the magnetic sensitive direction of the magnetic resistance element.

[0009] According to some embodiments of the present invention, the magnetic sensitivity direction of the magnetoresistive element is perpendicular to the rotation axis of the magnetic field source; The plurality of magnetic track-changing elements are located on the sides of each of the magnetoresistive elements. Each of the magnetic track-changing elements has a flat shape in a direction perpendicular to the magnetically sensitive direction of the magnetoresistive element.

[0010] According to some embodiments of the present invention, the plurality of magnetic track-changing elements include a plurality of first magnetic track-changing elements and a plurality of second magnetic track-changing elements; The plurality of magnetoresistive sub-elements are coupled to form a first Wheatstone bridge and a second Wheatstone bridge; The magnetic sensitive direction of each magnetoresistive element in the first Wheatstone bridge is parallel or antiparallel to the first direction, and the first magnetic switching element on its side has a flat shape in a second direction orthogonal to the first direction; The magnetic sensitive direction of each magnetoresistive element in the second Wheatstone bridge is parallel or antiparallel to the second direction, and the second magnetic switching element on its side has a flat shape in the first direction.

[0011] According to some embodiments of the present invention, the first Wheatstone bridge includes a first magnetoresistive arm, a second magnetoresistive arm, a third magnetoresistive arm, and a fourth magnetoresistive arm coupled to each other; the magnetically sensitive directions of the first magnetoresistive arm and the third magnetoresistive arm are a first direction; and the magnetically sensitive directions of the second magnetoresistive arm and the fourth magnetoresistive arm are a third direction antiparallel to the first direction; The second Wheatstone bridge includes a fifth magnetoresistance arm, a sixth magnetoresistance arm, a seventh magnetoresistance arm and an eighth magnetoresistance arm coupled to each other; the magnetic sensitivity direction of the fifth magnetoresistance arm and the seventh magnetoresistance arm is a second direction; the magnetic sensitivity direction of the sixth magnetoresistance arm and the seventh magnetoresistance arm is a fourth direction antiparallel to the second direction.

[0012] According to some embodiments of the present invention, under zero magnetic field, the resistance of each magnetoresistive arm in the first Wheatstone bridge is the same as the resistance of each magnetoresistive arm in the second Wheatstone bridge.

[0013] A second aspect of the present invention provides an angle sensor, comprising: a shaft rotatable about an axis of rotation; a magnetic field source connected to the shaft; a magnetoresistive element, located above or below the magnetic field source, configured to sense the magnetic field generated by the magnetic field source and output at least a third signal; the magnetoresistive element being the magnetoresistive element according to any one of claims 1 to 7; A signal processing unit is electrically coupled to the magnetoresistive element and is configured to determine rotation angle information of the magnetic field source or a device fixed to the magnetic field source based on the at least one third signal.

[0014] According to some embodiments of the present invention, the angle sensor further comprises: The magnetic shielding member is used to shield the external magnetic field around the magnetoresistive element.

[0015] A third aspect of the present invention provides an electronic device, characterized in that the electronic device includes the aforementioned magnetoresistive element or the aforementioned angle sensor.

[0016] Therefore, compared with the prior art, the present invention has the following beneficial effects: The magnetoresistive element provided by the present invention includes: a plurality of magnetoresistive elements, the magnetoresistive elements being used to sense the in-plane magnetic field component acting on the magnetoresistive element in the magnetic field generated by a magnetic field source, and outputting a linearly varying first signal in response to the in-plane magnetic field component within a preset magnetic field range; the magnetoresistive element including a plurality of magnetic tunnel junctions, wherein the sensing layer in the magnetic tunnel junction has a closed vortex magnetization pattern; a plurality of magnetic track-changing elements, located around the plurality of magnetoresistive elements, being used to adjust the magnetic field distribution of the magnetic field generated by the magnetic field source around each magnetoresistive element, so that the first signal is related to the rotation angle of the magnetic field source. The present invention, through the synergistic effect of the magnetoresistive elements and the magnetic track-changing elements, enables the magnetoresistive element to measure the angle information of the magnetic field source within a linear range, avoiding the problem of low angle measurement accuracy caused by a slight offset of the reference layer due to the strong magnetic field generated by the magnetic field source, and achieving the beneficial effect of simple structure and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0018] Figure 1 A schematic structural diagram of a magnetoresistive element and a magnetic field source according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of a magnetoresistive element according to an embodiment of the present invention; Figure 3 The following is a simulation curve showing the change of the X-axis magnetic field at each center position above the magnetic field source over time when a pair of proportional magnetoresistive elements of the present invention are placed at the center position above the magnetic field source and the magnetic field source is in a rotating state; Figure 4 The following is a simulation curve showing the change of the Y-axis magnetic field at each center position above the magnetic field source over time when a proportional magnetoresistive element of the present invention is placed at the center position above the magnetic field source and the magnetic field source is in a rotating state; Figure 5The following is a simulation curve showing the change of the X-axis magnetic field at each center position above the magnetic field source over time when a proportional magnetoresistive element of the present invention is placed at the center position above the magnetic field source and the magnetic field source is in a rotating state; Figure 6 The following is a simulation curve showing the change of the X-axis magnetic field at each eccentric position above the magnetic field source over time when a proportional magnetoresistive element of the present invention is placed at an eccentric position above the magnetic field source and the magnetic field source is in a rotating state; Figure 7 The following is a simulation curve showing the change of the Y-axis magnetic field at each eccentric position above the magnetic field source over time when a proportional magnetoresistive element of the present invention is placed at an eccentric position above the magnetic field source and the magnetic field source is in a rotating state; Figure 8 The following is a simulation curve showing the change of the Z-axis magnetic field at the eccentric position above the magnetic field source over time when a proportional magnetoresistive element of the present invention is placed at an eccentric position above the magnetic field source and the magnetic field source is in a rotating state; Figure 9 A comparison of simulation curves of the X-axis magnetic field at the eccentric position above the magnetic field source versus time when the magnetoresistive element according to an embodiment of the present invention and a comparable magnetoresistive element are respectively placed at eccentric positions above the magnetic field source and the magnetic field source is in a rotating state; Figure 10 A comparison of simulation curves of the Y-axis magnetic field at the eccentric position above the magnetic field source versus time when the magnetoresistive element according to an embodiment of the present invention and a comparable magnetoresistive element are respectively placed at eccentric positions above the magnetic field source and the magnetic field source is in a rotating state; Figure 11 A comparison of simulation curves of the Z-axis magnetic field at the eccentric position above the magnetic field source versus time when the magnetoresistive element according to an embodiment of the present invention and a comparable magnetoresistive element are placed at eccentric positions above the magnetic field source and the magnetic field source is rotating; Figure 12 FIG1 is a graph showing how the output signal of a magnetoresistive element changes with magnetic field under different bias magnetic fields according to an embodiment of the present invention.

[0019] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] When spin valve magnetoresistive angle sensing units such as TMR or GMR are in normal use, the magnetic moment of the reference layer does not change with the direction of the external magnetic field, and the value of the external magnetic field must be much larger than the saturation magnetic field of the free layer so that the magnetic moment of the free layer is consistent with the direction of the external magnetic field.

[0024] However, in actual measurements, an excessively high external magnetic field often causes a slight offset in the magnetic moment of the reference layer in the magnetoresistive angle sensor unit, resulting in low angle measurement accuracy.

[0025] An embodiment of the present invention provides a magnetoresistive element for angle measurement to improve the problem of low angle measurement accuracy in existing magnetoresistive angle sensing units caused by slight deviation of the magnetic moment of a reference layer due to an external strong magnetic field.

[0026] like Figure 1 As shown, the magnetoresistive element for angle measurement of this embodiment includes a plurality of magnetoresistive sub-elements 100 and a plurality of magnetic switching elements 200 located above a substrate 300 ; the magnetoresistive element can be used to realize angle measurement of a magnetic field source above or below it.

[0027] The plane where the magnetic field source is located, the plane where the substrate 300 and each magnetoresistive element 100 are located, and the plane where each magnetic switching element 200 is located are all parallel to the XY plane, that is, parallel to the orthogonal X axis and Y axis respectively.

[0028] The magnetic field source 400 may be a permanent magnet connected to a shaft rotatable about a rotation axis. The rotation axis is parallel to the Z axis and perpendicular to the X axis and the Y axis. The magnetic field source is disconnected from the magnetoresistive element.

[0029] The magnetic field source can generate a radial magnetic field parallel to the XY plane. The radial magnetic field is parallel to the substrate plane, and the magnetic sensitive direction of each magnetoresistive element is also parallel to the substrate plane.

[0030] The magnetic field component of the radial magnetic field acting on each magnetoresistive sub-element in the magnetoresistive element along the magnetic sensitive direction of the magnetoresistive sub-element may vary with the rotation angle of the magnetic field source, the distance between the magnetic field source and the magnetic field sub-element, and other factors.

[0031] The distance between each magnetoresistive sub-element and the magnetic field source should be greater than the first distance, so that the in-plane magnetic field component induced by the magnetoresistive sub-element is smaller than the saturation magnetic field of the magnetoresistive sub-element.

[0032] Each magnetoresistive sub-element in the embodiment of the present invention is located below the magnetic field source at an eccentric position away from the center of the magnetic field source.

[0033] It should be noted that the eccentric position below the magnetic field source that deviates from the center position of the magnetic field source has not only a different Z-axis position from the center position of the magnetic field source, but also a different X-axis position and / or Y-axis position.

[0034] The multiple magnetoresistive sub-elements 100 are configured to sense the in-plane magnetic field component acting on each magnetoresistive sub-elements 100 within the magnetic field generated by the magnetic field source 400 and output a linearly varying first signal in response to the in-plane magnetic field component within a predetermined magnetic field range. The magnetoresistive sub-elements 100 include multiple magnetic tunnel junctions, each of which has a sensing layer having a closed vortex magnetization pattern.

[0035] The magnetic tunnel junction at least includes a sensing layer, a tunneling layer, and a reference layer coupled in sequence, wherein the reference layer has a fixed pinning direction.

[0036] The output signal of the magnetoresistive element changes with the magnetic field as shown in the following figure Figure 12 As shown. The preset magnetic field range of the magnetoresistive element is less than ±60 Oe. The in-plane magnetic field component acting on each magnetoresistive element in the magnetic field generated by the magnetic field source is the magnetic field generated by the magnetic field source and exists at the location of the magnetoresistive element and is parallel to the magnetic sensitivity direction of each magnetoresistive element. Figure 12 As shown in FIG5 , when in-plane X-axis magnetic fields of 0 Oe, 5 Oe, 10 Oe, 15 Oe and 20 Oe are applied around the magnetoresistive element, the magnetic field variation curve of the magnetoresistive element basically does not change with the increase of the bias magnetic field.

[0037] It should be noted that the magnetoresistive element is formed by coupling multiple magnetic tunnel junctions in series and / or in parallel. The multiple magnetoresistive elements can be coupled in series to form one or more Wheatstone bridges. The Wheatstone bridge can output a linearly varying second signal in response to the in-plane magnetic field component sensed by it within a preset magnetic field range.

[0038] The magnetic track-changing elements 200 of the embodiment of the present invention are located around each magnetoresistive element 100 and are used to adjust the magnetic field distribution around each magnetoresistive element 100 of the magnetic field generated by the magnetic field source 400 so that the first signal output by the magnetoresistive element is related to the rotation angle of the magnetic field source 400.

[0039] In the magnetic field generated by the magnetic source of the embodiment of the present invention, the magnetic field acting on each magnetoresistive element perpendicular to its magnetic sensitivity direction is significantly weakened due to the action of the magnetic switching element. Simultaneously, the magnetic field acting on each magnetoresistive element parallel to its magnetic sensitivity direction is significantly enhanced due to the action of the magnetic switching element. This allows the first signal output by the magnetoresistive element to directly reflect the rotation angle of the magnetic field source. The magnetic switching element may be made of a soft magnetic material such as NiFe, which is not specifically limited herein.

[0040] Each magnetic commutation element 200 is located to the side of each magnetoresistive element 100; each magnetic commutation element 200 is flattened in a direction perpendicular to the magnetic sensitivity direction of the magnetoresistive element 100. The magnetic commutation element 200 is capable of converging magnetic field components acting on the magnetoresistive element 100 that are parallel to the magnetic sensitivity direction of the magnetoresistive element 100, while simultaneously reducing magnetic field components acting on the magnetoresistive element 100 that are perpendicular to the magnetic sensitivity direction of the magnetoresistive element 100. When the magnetic sensitivity direction of the magnetoresistive element is a first magnetic sensitivity direction within a plane, the magnetic commutation element is capable of converging magnetic field components in the first magnetic sensitivity direction at the location of the magnetoresistive element, reducing magnetic field components perpendicular to the first magnetic sensitivity direction within the plane at the location of the magnetoresistive element, and simultaneously reducing the Z-axis magnetic field component at the location of the magnetoresistive element.

[0041] The sensing layer in the magnetic tunnel junction of an embodiment of the present invention has a closed vortex magnetization pattern. The magnetoresistive element including the magnetic tunnel junction can output a linearly varying first signal in response to the in-plane magnetic field component within a non-saturated preset magnetic field range. Under the action of the magnetic track switching element, the first signal output by the magnetoresistive element can be related to the rotation angle of the magnetic field source, thereby achieving the purpose of measuring the angle of the magnetic field source. At the same time, since the magnetic field intensity in the preset magnetic field range is generally small, it is not easy to cause the magnetic moment of the reference layer in the magnetoresistive element to shift, thereby improving the measurement accuracy of the magnetoresistive element.

[0042] To reduce temperature dependence, the multiple magnetoresistive elements in this embodiment of the present invention are coupled to form a Wheatstone bridge structure. Because a single Wheatstone bridge only provides a one-to-one correspondence between its output signal and the rotation angle of the magnetic field source within a range of 0-180 degrees, to enable the magnetoresistive elements to measure angles within the range of 0-360 degrees, the multiple magnetoresistive elements in this embodiment of the present invention are coupled to form two Wheatstone bridges with orthogonal phases.

[0043] like Figure 2 As shown, the magnetoresistive element of the embodiment of the present invention includes a first Wheatstone bridge 110 and a second Wheatstone bridge 120 formed by coupling a plurality of magnetoresistive sub-elements, a first magnetic track switching element 210 located on the side of each magnetoresistive arm of the first Wheatstone bridge 110, and a second magnetic track switching element 220 located on the side of each magnetoresistive arm of the second Wheatstone bridge 120. Each magnetoresistive arm includes one magnetoresistive sub-element.

[0044] It should be noted that the magnetoresistive arm can be one or more mutually coupled magnetoresistive sub-elements, which is not specifically limited here. The magnetic tunnel junctions in each magnetoresistive arm have the same magnetic sensitivity direction; the magnetic tunnel junctions in adjacent magnetoresistive arms have opposite magnetic sensitivity directions; and the magnetic tunnel junctions in the first Wheatstone bridge and the magnetic tunnel junctions in the second Wheatstone bridge have orthogonal magnetic sensitivity directions.

[0045] The magnetic sensitivity direction of each magnetoresistive element in the first Wheatstone bridge 110 is parallel or antiparallel to the Y-axis, i.e., the first direction. The magnetic sensitivity direction of each magnetoresistive element in the second Wheatstone bridge 120 is parallel or antiparallel to the X-axis, i.e., the second direction, where the second direction is orthogonal to the first direction. Consequently, the signals output by the first and second Wheatstone bridges can vary in a sinusoidal and cosine curve, respectively, as the rotation angle of the magnetic field source changes.

[0046] like Figure 2 As shown, the first Wheatstone bridge 110 includes a first magnetoresistance arm 111, a second magnetoresistance arm 112, a third magnetoresistance arm 113 and a fourth magnetoresistance arm 114 coupled to each other; the magnetic sensitivity direction of the first magnetoresistance arm 111 and the third magnetoresistance arm 113 is a first direction; the magnetic sensitivity direction of the second magnetoresistance arm 113 and the fourth magnetoresistance arm 114 is a third direction antiparallel to the first direction; each magnetoresistance arm is composed of one magnetoresistance sub-element.

[0047] The second Wheatstone bridge 120 includes a fifth magnetoresistive arm 121, a sixth magnetoresistive arm 122, a seventh magnetoresistive arm 123 and an eighth magnetoresistive arm 124 coupled to each other; the magnetic sensitivity direction of the fifth magnetoresistive arm 121 and the seventh magnetoresistive arm 123 is the second direction; the magnetic sensitivity direction of the sixth magnetoresistive arm 122 and the eighth magnetoresistive arm 124 is a fourth direction antiparallel to the second direction; each magnetoresistive arm is composed of one magnetoresistive sub-element.

[0048] The first magnetic track change element 210 is located on the side of each magnetic resistance sub-element of the first Wheatstone bridge 110, and has a flat shape in the X-axis direction, that is, the second direction; the second magnetic track change element 220 is located on the side of each magnetic resistance sub-element of the second Wheatstone bridge 120, and has a flat shape in the Y-axis direction, that is, the first direction.

[0049] Under zero magnetic field, the resistance of each magnetoresistive arm in the first Wheatstone bridge 110 is the same as the resistance of each magnetoresistive arm in the second Wheatstone bridge.

[0050] It should be noted that, in the embodiment of the present invention, the in-plane magnetic field component generated by the magnetic field source and acting on each magnetoresistive element should be smaller than the saturation magnetic field of the magnetoresistive element.

[0051] The in-plane magnetic field component can be adjusted by the distance between the magnetic field source and the magnetoresistive sub-element. The farther the distance between the magnetoresistive sub-element and the magnetic field source, the smaller the in-plane magnetic field component of each magnetoresistive sub-element.

[0052] The following demonstrates the magnetic field measurement performance of the example magnetoresistive element and the comparative example magnetoresistive element. The difference between the example magnetoresistive element and the comparative example magnetoresistive element lies in the presence of a magnetic switching element surrounding the example magnetoresistive element. The magnetic switching element is flattened in a direction perpendicular to the magnetoresistive element's magnetic sensitivity direction; the magnetic sensitivity direction of each magnetoresistive element is parallel to the Y-axis. The center of the magnetic field source is assumed to be (0, 0, 0).

[0053] The magnetic field source rotates at a speed of 360 degrees / s. The comparative magnetic resistance sub-element is placed above the magnetic field source at 2mm, 2.5mm, 3mm, 3.5mm, and 3.8mm from the center of the magnetic field source, i.e., (0,0,2), (0,0,2.5), (0,0,3), (0,0,3.5), and (0,0,3.8). The X-axis magnetic field, Y-axis magnetic field, and Z-axis magnetic field at each center position are simulated over time. The simulation curve of the X-axis magnetic field at the center position above the magnetic field source over time is shown as follows: Figure 3 As shown; the simulation curve of the Y-axis magnetic field at the center position above the magnetic field source changing with time is shown as Figure 4 As shown; the simulation curve of the Z-axis magnetic field at the center position above the magnetic field source changing with time is shown as Figure 5 shown.

[0054] Note that the position 2 mm above the magnetic field source, which is 2 mm from the center of the magnetic field source, has the same X and Y axes as the center of the magnetic field source, but differs only in its Z-axis position. For example, if the coordinates of the magnetic field source center are (x, y, z), then the coordinates of the position 2 mm above the magnetic field source, which is 2 mm from the center of the magnetic field source, are (x, y, z + 2).

[0055] in accordance with Figure 3-5 During the rotation of the magnetic field source, the X-axis, Y-axis, and Z-axis magnetic fields at the center position above the magnetic field source all vary with time, with a period of 1 second, or 360 degrees. The X-axis magnetic field variation curve follows a sine curve, with a maximum X-axis magnetic field intensity ranging from 0.1 to 0.16 T, which decreases with increasing distance between the magnetic field source and the magnetoresistive element. The Y-axis magnetic field intensity variation curve follows a cosine curve, with a maximum Y-axis magnetic field intensity ranging from 0.09 to 0.145 T, which decreases with increasing distance between the magnetic field source and the magnetoresistive element. The maximum Z-axis magnetic field intensity is only 0.0003 to 0.0035 T. This indicates that when the comparative magnetoresistive element is located at the center, the maximum X-axis magnetic field intensity at the center is slightly higher than the maximum Y-axis magnetic field intensity.

[0056] The magnetic field source rotates at a speed of 360 degrees / s. The comparative magnetic resistance sub-element is placed above the magnetic field source at eccentric positions of 2mm, 2.5mm, 3mm, 3.5mm, and 3.8mm from the magnetic field source and 1mm away from the center position, namely (1,0,2), (1,0,2.5), (1,0,3), (1,0,3.5), and (1,0,3.8). The X-axis magnetic field, Y-axis magnetic field, and Z-axis magnetic field at each eccentric position are simulated over time. When the magnetic field source is rotating, the simulation curve of the X-axis magnetic field at the eccentric position above the magnetic field source over time is shown as follows: Figure 6 As shown; the simulation curve of the Y-axis magnetic field at the eccentric position above the magnetic field source changing with time is shown as Figure 7 As shown; the simulation curve of the Z-axis magnetic field at the eccentric position above the magnetic field source changing with time is shown as Figure 8 shown.

[0057] It should be noted that an off-center position 2 mm above the magnetic field source and 1 mm away from the center has a different Z-axis position, X-axis position, and / or Y-axis position from the center of the magnetic field source. If the coordinates of the center of the magnetic field source are (x, y, z), then the off-center position can be (x + cosθ, y + sinθ, z + 2), specifically (x + 1, y, z + 2) or (x - 1, y, z + 2).

[0058] in accordance with Figure 6-8During the rotation of the magnetic field source, the X-axis magnetic field, Y-axis magnetic field, and Z-axis magnetic field at the eccentric position above the magnetic field source also change over time with a period of 1 second, or 360 degrees. The X-axis magnetic field intensity variation curve over time still follows a sine curve, with the maximum magnetic field intensity of the X-axis magnetic field ranging from 0.08 to 0.14 T, and this maximum magnetic field intensity decreases as the distance between the magnetic field source and the magnetoresistive element increases. The Y-axis magnetic field intensity variation curve over time follows a cosine curve, with the maximum magnetic field intensity of the Y-axis magnetic field ranging from 0.08 to 0.14 T, and this maximum magnetic field intensity decreases as the distance between the magnetic field source and the magnetoresistive element increases. The maximum magnetic field intensity of the Z-direction magnetic field at the eccentric position above the magnetic field source is smaller. This shows that when the comparative magnetoresistive element is located at an eccentric position, the maximum magnetic field intensity of the X-axis magnetic field at the eccentric position is equal to the maximum magnetic field intensity of the Y-axis magnetic field. Therefore, when determining the position of the magnetoresistive element and the magnetic field source, it is preferred to place the magnetoresistive element at an eccentric position above or below the magnetic field source.

[0059] The magnetic field source rotates at a speed of 360 degrees / s. The magnetoresistive element of the embodiment of the present invention and the magnetoresistive element of the comparative example are respectively placed above the magnetic field source at an eccentric position (1, 0.011, 2.501) with a distance of 2.501mm from the magnetic field source, 1mm from the center position in the X-axis direction, and 0.011mm from the center position in the Y-axis direction. The time-varying X-axis magnetic field, the Y-axis magnetic field, and the Z-axis magnetic field at the eccentric position are respectively simulated. When the magnetoresistive element of the embodiment of the present invention and the magnetoresistive element of the comparative example are respectively located at the eccentric position, the simulation curve comparison of the time-varying X-axis magnetic field at the eccentric position is shown in the figure below. Figure 9 As shown; the simulation curve comparison of the Y-axis magnetic field at the eccentric position changing with time is shown in Figure 10 As shown; the simulation curve comparison of the Z-axis magnetic field at the eccentric position changing with time is shown in Figure 11 shown.

[0060] in accordance with Figure 9-11 When the magnetoresistive element of the embodiment of the present invention and the magnetoresistive element of the comparative example are located at the same eccentric position, the presence of the magnetic switching element weakens the maximum magnetic field strength of the X-axis magnetic field corresponding to the magnetoresistive element at the eccentric position from greater than 0.11 T to less than 0.02 T, while the maximum magnetic field strength of the Y-axis magnetic field increases from less than 0.12 T to 0.16 T, and the maximum magnetic field strength of the Z-axis magnetic field weakens from 0.05 T to less than 0.003 T. This indicates that placing the magnetic switching element on the side of the magnetoresistive element with its magnetic sensitivity direction parallel to the Y-axis can enhance the Y-axis magnetic field strength at that location while significantly weakening the X-axis and Z-axis magnetic fields at that location.

[0061] Since the distance between the magnetoresistive element and the magnetic field source in this embodiment in the above simulation is 2.501 mm, by increasing the distance between the magnetoresistive element and the magnetic field source, the strength of the X-axis magnetic field and the Z-axis magnetic field at the location of the magnetoresistive element can be further weakened. This shows that when the distance between the magnetoresistive element and the magnetic field source is greater than the first distance, the X-axis magnetic field and the Z-axis magnetic field at the location of the magnetoresistive element can be ignored. The magnitude of the Y-axis magnetic field generated by the magnetic field source can be obtained by using a magnetoresistive element with a magnetic sensitivity direction of the Y axis or a Wheatstone bridge having such a magnetoresistive element, thereby achieving measurement of any angle of the magnetic field source from 0 to 180 degrees; or the magnitude of the X-axis magnetic field generated by the magnetic field source can be obtained by using a magnetoresistive element with a magnetic sensitivity direction of the X axis or a Wheatstone bridge having such a magnetoresistive element, thereby achieving measurement of any angle of the magnetic field source from 0 to 180 degrees; or the measurement of any angle of the magnetic field source within the range of 0 to 360 degrees can be achieved by using a magnetoresistive element composed of two Wheatstone bridges with orthogonal magnetic sensitivity directions.

[0062] The magnetoresistive element is used to measure the magnetic field along the X-axis or Y-axis. The sensing layer of the magnetoresistive element preferably has a closed vortex structure. The magnetoresistive element can output a signal related to the rotation angle of the magnetic field source within its linear magnetic field range.

[0063] Since the distance between the magnetoresistive element and the magnetic field source is adjustable, and the greater the distance, the smaller the magnetic field strength at the location of the magnetoresistive element, the magnetoresistive element of the embodiment of the present invention can use this distance to make the magnetic field strength at the location of the magnetoresistive element within the linear range of the magnetoresistive element.

[0064] Therefore, the magnetoresistive element of the embodiment of the present invention realizes the angle measurement of the magnetic field source above or below the magnetoresistive element through the linear interval. Since its linear interval is small, it can avoid the problem of low angle measurement accuracy caused by the magnetic moment of the reference layer of the magnetic tunnel junction being offset due to the excessive magnetic field strength at the location of the magnetoresistive element.

[0065] An embodiment of the present invention also provides an angle sensor, which includes an axis rotatable around a rotation line, a magnetic field source connected to the axis, the above-mentioned magnetoresistive element and a signal processing unit, wherein the magnetoresistive element is located above or below the magnetic field source and is used to sense the magnetic field generated by the magnetic field source and output at least one third signal; the signal processing unit is electrically coupled to the magnetoresistive element and is used to determine the rotation angle information of the magnetic field source or a device fixed to the magnetic field source based on the at least one third signal.

[0066] The magnetoresistive element of an embodiment of the present invention is located at an eccentric position above the magnetic field source, deviating from the center position of the magnetic field source. The distance between the magnetoresistive element and the magnetic field source is greater than the first distance so that the in-plane magnetic field component induced by each magnetoresistive sub-element in the magnetoresistive element is smaller than the saturation magnetic field of each magnetoresistive sub-element.

[0067] It should be noted that the magnetoresistive element is not limited to being located above the magnetic field source at an eccentric position, offset from the center of the magnetic field source; it may also be located above the magnetic field source at an eccentric position, offset from the center of the magnetic field source, or located above or at a central position above the magnetic field source. When the magnetoresistive element includes two Wheatstone bridges, it is preferably placed at this eccentric position to reduce subsequent signal processing.

[0068] The magnetoresistive element in the angle sensor of an embodiment of the present invention preferably has two Wheatstone power supply bridge structures, and the magnetoresistive element is used to sense the magnetic field generated by the magnetic field source and output two third signals; the signal processing unit is used to determine the rotation angle information of the magnetic field source or a device fixed to the magnetic field source based on the two third signals.

[0069] To avoid interference from an external magnetic field, the angle sensor according to the embodiment of the present invention further includes a magnetic shielding member, which is used to shield the external magnetic field around the magnetoresistive element.

[0070] An embodiment of the present invention further provides an electronic device, which includes the above-mentioned magnetoresistive element or angle sensor.

[0071] Therefore, the present invention uses the synergistic effect of the various magnetoresistive elements and magnetic track-changing elements in the magnetoresistive element to enable the magnetoresistive element to measure the angle information of the magnetic field source within the linear range, avoiding the problem of low angle measurement accuracy caused by a slight offset of the reference layer due to the strong magnetic field generated by the magnetic field source, and achieving the beneficial effect of simple structure and easy implementation.

[0072] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by utilizing the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A magnetoresistive element, characterized in that: include: A plurality of magnetoresistive sub-elements, each configured to sense an in-plane magnetic field component acting on each magnetoresistive sub-element in a magnetic field generated by a magnetic field source, and output a linearly varying first signal within a preset magnetic field range in response to the in-plane magnetic field component; wherein the magnetoresistive sub-elements include a plurality of magnetic tunnel junctions, each having a sensing layer having a closed vortex magnetization pattern; A plurality of magnetic track changing elements are located around each of the magnetic resistance sub-elements and are used to adjust the magnetic field distribution of the magnetic field generated by the magnetic field source around each of the magnetic resistance sub-elements so that the first signal is correlated with the rotation angle of the magnetic field source.

2. The magnetoresistive element according to claim 1, wherein The distance between the magnetoresistive element and the magnetic field source is greater than a first distance, so that the in-plane magnetic field component induced by the magnetoresistive element is smaller than the saturation magnetic field of the magnetoresistive element.

3. The magnetoresistive element according to claim 1, wherein The magnetic track changing element can converge the magnetic field component acting on the magnetoresistive element parallel to the magnetic sensitive direction of the magnetoresistive element, while reducing the magnetic field component acting on the magnetoresistive element orthogonal to the magnetic sensitive direction of the magnetoresistive element.

4. The magnetoresistive element according to claim 3, wherein The magnetic sensitive direction of the magnetoresistive element is perpendicular to the rotation axis of the magnetic field source; The plurality of magnetic track-changing elements are located on the sides of each of the magnetoresistive elements. Each of the magnetic track-changing elements has a flat shape in a direction perpendicular to the magnetically sensitive direction of the magnetoresistive element.

5. The magnetoresistive element according to claim 1, wherein The plurality of magnetic track-changing elements include a plurality of first magnetic track-changing elements and a plurality of second magnetic track-changing elements; The plurality of magnetoresistive sub-elements are coupled to form a first Wheatstone bridge and a second Wheatstone bridge; The magnetic sensitive direction of each magnetoresistive element in the first Wheatstone bridge is parallel or antiparallel to the first direction, and the first magnetic switching element on its side has a flat shape in a second direction orthogonal to the first direction; The magnetic sensitive direction of each magnetoresistive element in the second Wheatstone bridge is parallel or antiparallel to the second direction, and the second magnetic switching element on its side has a flat shape in the first direction.

6. The magnetoresistive element according to claim 5, wherein The first Wheatstone bridge includes a first magnetoresistive arm, a second magnetoresistive arm, a third magnetoresistive arm, and a fourth magnetoresistive arm coupled to each other; the magnetic sensitivity direction of the first magnetoresistive arm and the third magnetoresistive arm is a first direction; the magnetic sensitivity direction of the second magnetoresistive arm and the fourth magnetoresistive arm is a third direction antiparallel to the first direction; The second Wheatstone bridge includes a fifth magnetoresistance arm, a sixth magnetoresistance arm, a seventh magnetoresistance arm and an eighth magnetoresistance arm coupled to each other; the magnetic sensitivity direction of the fifth magnetoresistance arm and the seventh magnetoresistance arm is a second direction; the magnetic sensitivity direction of the sixth magnetoresistance arm and the seventh magnetoresistance arm is a fourth direction antiparallel to the second direction.

7. The magnetoresistive element according to claim 5, wherein Under zero magnetic field, the resistance of each magnetoresistive arm in the first Wheatstone bridge is the same as the resistance of each magnetoresistive arm in the second Wheatstone bridge.

8. An angle sensor, characterized in that: include: a shaft rotatable about an axis of rotation; a magnetic field source connected to the shaft; a magnetoresistive element, located above or below the magnetic field source, configured to sense the magnetic field generated by the magnetic field source and output at least a third signal; the magnetoresistive element being the magnetoresistive element according to any one of claims 1 to 7; A signal processing unit is electrically coupled to the magnetoresistive element and is configured to determine rotation angle information of the magnetic field source or a device fixed to the magnetic field source based on the at least one third signal.

9. The angle sensor according to claim 8, characterized in that: Also includes: The magnetic shielding member is used to shield the external magnetic field around the magnetoresistive element.

10. An electronic device, characterized in that: The electronic device includes the magnetoresistive element according to any one of claims 1 to 7 or the angle sensor according to claim 8 or 9.

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