Magnetoresistive angle sensor

Abstract

The application provides a kind of magnetoresistive angle sensor, it includes: first magnetoresistive sensor, it includes the first magnetoresistive sensor unit, second magnetoresistive sensor unit, third magnetoresistive sensor unit and fourth magnetoresistive sensor unit interconnected to establish first Wheatstone bridge;Second magnetoresistive sensor, it includes the fifth magnetoresistive sensor unit, sixth magnetoresistive sensor unit, seventh magnetoresistive sensor unit and eighth magnetoresistive sensor unit interconnected to establish second Wheatstone bridge;Wherein each described magnetoresistive sensor unit includes several photoetching circular magnetic thin films and several metal films, and the several photoetching circular magnetic thin films are electrically interconnected by the several metal films.Compared with prior art, the application can eliminate shape anisotropy field and magnetic crystal anisotropy field, thereby significantly reducing the detection error of angle, improve the detection accuracy of angle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of angle sensor, in particular to a high-precision magnetoresistive angle sensor.

BACKGROUND

[0002] The traditional magnetoresistive angle sensor: on the one hand, due to the long strip shape of the magnetic thin film photoetched, shape anisotropy field is generated; on the other hand, due to the unidirectional bias magnetic field applied in the growth process of the magnetic thin film, magnetic crystal anisotropy field is generated. The appearance of shape anisotropy field and magnetic crystal anisotropy field makes the angle error of the traditional magnetoresistive angle sensor very large.

[0003] Therefore, it is necessary to provide a technical scheme to overcome the above problems.

SUMMARY

[0004] One of the purposes of the present application is to provide a magnetoresistive angle sensor which can significantly reduce the detection error of the angle and improve the detection accuracy of the angle.

[0005] According to one aspect of the present application, the present application provides a magnetoresistive angle sensor, comprising: a first magnetoresistive sensor comprising a first magnetoresistive sensor unit, a second magnetoresistive sensor unit, a third magnetoresistive sensor unit and a fourth magnetoresistive sensor unit interconnected to establish a first Wheatstone bridge; a second magnetoresistive sensor comprising a fifth magnetoresistive sensor unit, a sixth magnetoresistive sensor unit, a seventh magnetoresistive sensor unit and an eighth magnetoresistive sensor unit interconnected to establish a second Wheatstone bridge; wherein each of the magnetoresistive sensor units comprises a plurality of circularly photoetched magnetic thin films and a plurality of metal thin films, and the plurality of circularly photoetched magnetic thin films are electrically interconnected through the plurality of metal thin films.

[0006] Further, an in-plane rotating magnetic field is applied in the growth process of the magnetic thin film.

[0007] Further, the magnetic field strength of the rotating magnetic field is between 20 and 200 Gauss.

[0008] Further, in each of the magnetoresistive sensor units, the plurality of circularly photoetched magnetic thin films and the plurality of metal thin films are arranged in a spaced manner; each of the metal thin films is electrically interconnected with its adjacent circularly photoetched magnetic thin film.

[0009] Further, in each of the magnetoresistive sensor units, the plurality of circularly photoetched magnetic thin films and the plurality of metal thin films are arranged in a spaced manner along a straight line direction.

[0010] Further, the second magnetoresistance sensor is rotated 45 degrees in plane relative to the first magnetoresistance sensor; the first magnetoresistance sensor is orthogonally arranged; and the second magnetoresistance sensor is orthogonally arranged.

[0011] Further, the first, second, third, fourth, fifth, sixth, seventh and eighth magnetoresistance sensor units are arranged in a cross shape around the center point A.

[0012] Further, the first magnetoresistance sensor further comprises a first power supply end vddx, a first ground end gndx, a first output end x1 and a second output end x2; the first end of the first magnetoresistance sensor unit and the first end of the second magnetoresistance sensor unit are connected to the first power supply end vddx; the first end of the third magnetoresistance sensor unit and the first end of the fourth magnetoresistance sensor unit are connected to the first ground end gndx; the second end of the first magnetoresistance sensor unit and the second end of the fourth magnetoresistance sensor unit are connected to the second output end x2; the second end of the second magnetoresistance sensor unit and the second end of the third magnetoresistance sensor unit are connected to the first output end x1; the second magnetoresistance sensor further comprises a second power supply end vddy, a second ground end gndy, a third output end y1 and a fourth output end y2; the first end of the fifth magnetoresistance sensor unit and the first end of the sixth magnetoresistance sensor unit are connected to the second power supply end vddy; the first end of the seventh magnetoresistance sensor unit and the first end of the eighth magnetoresistance sensor unit are connected to the second ground end gndy; the second end of the fifth magnetoresistance sensor unit and the second end of the eighth magnetoresistance sensor unit are connected to the fourth output end y2; and the second end of the sixth magnetoresistance sensor unit and the second end of the seventh magnetoresistance sensor unit are connected to the third output end y1.

[0013] Further, the first magnetoresistance sensor is orthogonally arranged, wherein the first magnetoresistance sensor unit and the third magnetoresistance sensor unit are parallel to each other and orthogonal to the second magnetoresistance sensor unit and the fourth magnetoresistance sensor unit which are parallel to each other; and the second magnetoresistance sensor is orthogonally arranged, wherein the fifth magnetoresistance sensor unit and the seventh magnetoresistance sensor unit are parallel to each other and orthogonal to the sixth magnetoresistance sensor unit and the eighth magnetoresistance sensor unit which are parallel to each other.

[0014] Further, the first end of the magnetoresistance sensor unit is the end close to the center point A; and the second end of the magnetoresistance sensor unit is the end away from the center point A.

[0015] Compared with the prior art, the application can eliminate the shape anisotropy field and the magnetocrystalline anisotropy field, thereby significantly reducing the detection error of the angle and improving the detection precision of the angle. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor. Among them:

[0017] Figure 1 Fig. 1 is a structural schematic diagram of a high-precision magnetoresistive angle sensor in an embodiment of the application.

[0018] Figure 2 Fig. 2 is a waveform comparison diagram of an angle error curve of a traditional magnetoresistive angle sensor and an angle error curve of the high-precision magnetoresistive angle sensor in an embodiment of the application. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned purposes, features and advantages of the application more apparent and easy to understand, the following will further describe the application in combination with the drawings and specific embodiments.

[0020] The term "one embodiment" or "an embodiment" as used herein means that a particular feature, structure, or characteristic described can be included in at least one implementation of the application. The appearances of the phrase "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a single, alternative embodiment, unless otherwise specifically indicated. The terms "connected," "coupled," or "in communication" as used herein, unless otherwise specifically indicated, mean either direct or indirect electrical connection.

[0021] In the description of the application, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the application. In the description of the application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0022] Please refer to Figure 1 Fig. 1 is a structural schematic diagram of a high-precision magnetoresistive angle sensor in an embodiment of the application. Figure 1The illustrated magnetoresistive angle sensor includes a first magnetoresistive sensor (not identified) and a second magnetoresistive sensor (not identified). The first magnetoresistive sensor includes a first magnetoresistive sensor unit 101a, a second magnetoresistive sensor unit 101b, a third magnetoresistive sensor unit 101c, and a fourth magnetoresistive sensor unit 101d, and the first magnetoresistive sensor unit 101a, the second magnetoresistive sensor unit 101b, the third magnetoresistive sensor unit 101c, and the fourth magnetoresistive sensor unit 101d are interconnected to form a first Wheatstone bridge. The second magnetoresistive sensor includes a fifth magnetoresistive sensor unit 102a, a sixth magnetoresistive sensor unit 102b, a seventh magnetoresistive sensor unit 102c, and an eighth magnetoresistive sensor unit 102d, and the fifth magnetoresistive sensor unit 102a, the sixth magnetoresistive sensor unit 102b, the seventh magnetoresistive sensor unit 102c, and the eighth magnetoresistive sensor unit 102d are interconnected to form a second Wheatstone bridge.

[0023] Each of the magnetoresistive sensor units 101a, 101b, 101c, 101d, 102a, 102b, 102c, and 102d includes a plurality of circularly photolithographic magnetic thin films 103 and a plurality of metal thin films 104, and the plurality of circularly photolithographic magnetic thin films 103 are electrically interconnected by the plurality of metal thin films 104. An in-plane rotating magnetic field 105 is applied during the growth of the magnetic thin films 103. In one embodiment, the magnetic field strength H of the rotating magnetic field 105 is between 20 and 200 Gauss.

[0024] To better illustrate the structure of the magnetoresistive angle sensor according to the present application, a plane rectangular coordinate system (i.e., an xy coordinate system) is defined in Figure 1 The positive direction of the x-axis is horizontally to the right, and the positive direction of the y-axis is vertically upward.

[0025] In the first magnetoresistive sensor, the first magnetoresistive sensor unit 101a forms a 0-degree angle with the positive direction of the x-axis; the second magnetoresistive sensor unit 101b forms a 90-degree angle with the positive direction of the x-axis; the third magnetoresistive sensor unit 101c forms a 180-degree angle with the positive direction of the x-axis; and the fourth magnetoresistive sensor unit 101d forms a 270-degree angle with the positive direction of the x-axis. In the second magnetoresistive sensor, the fifth magnetoresistive sensor unit 102a forms a 45-degree angle with the positive direction of the x-axis; the sixth magnetoresistive sensor unit 102b forms a 135-degree angle with the positive direction of the x-axis; the seventh magnetoresistive sensor unit 102c forms a 225-degree angle with the positive direction of the x-axis; and the eighth magnetoresistive sensor unit 102d forms a 315-degree angle with the positive direction of the x-axis.

[0026] It can also be said that the first magnetoresistance sensor is in a quadrature arrangement, in which the first magnetoresistance sensor unit 101a and the third magnetoresistance sensor unit 101c are parallel to each other, and orthogonal (or perpendicular) to the second magnetoresistance sensor unit 101b and the fourth magnetoresistance sensor unit 101d which are parallel to each other. The second magnetoresistance sensor is in a quadrature arrangement, in which the fifth magnetoresistance sensor unit 102a and the seventh magnetoresistance sensor unit 102c are parallel to each other, and orthogonal (or perpendicular) to the sixth magnetoresistance sensor unit 102b and the eighth magnetoresistance sensor unit 102d which are parallel to each other. The second magnetoresistance sensor is rotated 45 degrees in-plane with respect to the first magnetoresistance sensor (i.e. the second magnetoresistance sensor and the first magnetoresistance sensor are in the same plane, and the second magnetoresistance sensor is at a 45 degree angle with respect to the first magnetoresistance sensor), i.e. the direction of each magnetoresistance sensor unit in the second magnetoresistance sensor is offset by 45 degrees from the direction of the corresponding magnetoresistance sensor unit in the first magnetoresistance sensor, for example, the fifth magnetoresistance sensor unit 102a, the sixth magnetoresistance sensor unit 102b, the seventh magnetoresistance sensor unit 102c and the eighth magnetoresistance sensor unit 102d in the second magnetoresistance sensor are respectively offset by 45 degrees in-plane from the first magnetoresistance sensor unit 101a, the second magnetoresistance sensor unit 101b, the third magnetoresistance sensor unit 101c and the fourth magnetoresistance sensor unit 101d in the first magnetoresistance sensor.

[0027] In Figure 1 In the embodiment shown, the first magnetoresistance sensor further includes a first power supply terminal vddx, a first ground terminal gndx, a first output terminal x1, and a second output terminal x2. The first terminal of the first magnetoresistance sensor unit 101a and the first terminal of the second magnetoresistance sensor unit 101b are connected to the first power supply terminal vddx; the first terminal of the third magnetoresistance sensor unit 101c and the first terminal of the fourth magnetoresistance sensor unit 101d are connected to the first ground terminal gndx; the second terminal of the first magnetoresistance sensor unit 101a and the second terminal of the fourth magnetoresistance sensor unit 101d are connected to the second output terminal x2; and the second terminal of the second magnetoresistance sensor unit 101b and the second terminal of the third magnetoresistance sensor unit 101c are connected to the first output terminal x1.

[0028] In Figure 1In the shown embodiment, the second magnetoresistance sensor further comprises a second power supply end vddy, a second ground end gndy, a third output end yl, and a fourth output end y2. The first end of the fifth magnetoresistance sensor unit 102a and the first end of the sixth magnetoresistance sensor unit 102b are connected to the second power supply end vddy; the first end of the seventh magnetoresistance sensor unit 102c and the first end of the eighth magnetoresistance sensor unit 102d are connected to the second ground end gndy; the second end of the fifth magnetoresistance sensor unit 102a and the second end of the eighth magnetoresistance sensor unit 102d are connected to the fourth output end y2; and the second end of the sixth magnetoresistance sensor unit 102b and the second end of the seventh magnetoresistance sensor unit 102c are connected to the third output end yl.

[0029] In Figure 1 In the shown embodiment, in each of the magnetoresistance sensor units 101a, 101b, 101c, 101d, 102a, 102b, 102c, 102d, a plurality of photoetched circular magnetic films 103 and a plurality of metal films 104 are arranged in a spaced-apart manner; and each metal film 104 is electrically interconnected with its adjacent photoetched circular magnetic film 103.

[0030] In Figure 1 In the shown embodiment, in each of the magnetoresistance sensor units 101a, 101b, 101c, 101d, 102a, 102b, 102c, 102d, a plurality of photoetched circular magnetic films 103 and a plurality of metal films 104 are arranged in a spaced-apart manner along a straight line.

[0031] In Figure 1 In the shown embodiment, the first magnetoresistance sensor unit 101a, the second magnetoresistance sensor unit 101b, the third magnetoresistance sensor unit 101c, the fourth magnetoresistance sensor unit 101d, the fifth magnetoresistance sensor unit 102a, the sixth magnetoresistance sensor unit 102b, the seventh magnetoresistance sensor unit 102c, and the eighth magnetoresistance sensor unit 102d are arranged in a meander shape around the center point A; the first end of each of the magnetoresistance sensor units 101a, 101b, 101c, 101d, 102a, 102b, 102c, 102d is the end close to the point A (or the inner side of the magnetoresistance sensor unit); and the second end of each of the magnetoresistance sensor units 101a, 101b, 101c, 101d, 102a, 102b, 102c, 102d is the end away from the point A (or the outer side of the magnetoresistance sensor unit).

[0032] In conclusion, in the magnetic resistance angle sensor provided by the application, on the one hand, the shape anisotropy field is not generated due to the circular photoetching of the magnetic film; on the other hand, the magnetic crystal anisotropy field is not generated due to the application of the in-plane rotating magnetic field during the growth of the magnetic film. The elimination of the shape anisotropy field and the magnetic crystal anisotropy field makes the angle error of the high-precision magnetic resistance angle sensor provided by the application very small.

[0033] Please refer to Figure 2 Fig. 3 is a waveform comparison diagram of the angle error curve of the conventional magnetic resistance angle sensor and the angle error curve of the high-precision magnetic resistance angle sensor according to the application in one embodiment, as shown in the drawing. It can be seen from the drawing that Figure 2 the angle error of the conventional magnetic resistance angle sensor is more than 3 degrees, while the angle error of the high-precision magnetic resistance angle sensor according to the application is less than 0.1 degree. It can be seen that the shape anisotropy field and the magnetic crystal anisotropy field make the angle error of the conventional magnetic resistance angle sensor very large; the high-precision magnetic resistance angle sensor according to the application eliminates the shape anisotropy field and the magnetic crystal anisotropy field, so that the angle error is very small, thereby significantly improving the detection precision of the angle.

[0034] In the application, the words such as "connection", "connection", "connection", "connection" and the like represent electrical connection, and if not particularly stated, it represents direct or indirect electrical connection.

[0035] The above description is only the preferred embodiment of the application, and the protection scope of the application is not limited by the above embodiment. Any equivalent modification or change made by the ordinary skilled in the art according to the disclosure of the application shall be included in the protection scope recorded in the claims.

Claims

1. A magnetoresistive angle sensor, characterized in that It comprises: a first magnetoresistance sensor comprising a first magnetoresistance sensor unit, a second magnetoresistance sensor unit, a third magnetoresistance sensor unit and a fourth magnetoresistance sensor unit interconnected to establish a first Wheatstone bridge; a second magnetoresistance sensor comprising a fifth magnetoresistance sensor unit, a sixth magnetoresistance sensor unit, a seventh magnetoresistance sensor unit and an eighth magnetoresistance sensor unit interconnected to establish a second Wheatstone bridge; wherein each of the magnetoresistance sensor units comprises a plurality of circularly photoetched magnetic films and a plurality of metal films, the plurality of circularly photoetched magnetic films being electrically interconnected through the plurality of metal films, an in-plane rotating magnetic field is applied during growth of the magnetic films, in each of the magnetoresistance sensor units, the plurality of circularly photoetched magnetic films and the plurality of metal films are arranged in a linear direction.

2. The magnetoresistance angle sensor according to claim 1, wherein in each of the magnetoresistance sensor units, the plurality of circularly photoetched magnetic films and the plurality of metal films are arranged in a linear direction.

3. The magnetoresistance angle sensor according to claim 2, wherein the second magnetoresistance sensor is rotated in-plane by 45 degrees relative to the first magnetoresistance sensor; the first magnetoresistance sensor is arranged orthogonally; the second magnetoresistance sensor is arranged orthogonally.

4. The magnetoresistance angle sensor according to claim 3, wherein the first magnetoresistance sensor unit, the second magnetoresistance sensor unit, the third magnetoresistance sensor unit, the fourth magnetoresistance sensor unit, the fifth magnetoresistance sensor unit, the sixth magnetoresistance sensor unit, the seventh magnetoresistance sensor unit and the eighth magnetoresistance sensor unit are arranged in a meander shape around a center point A.

5. The magnetoresistance angle sensor according to claim 4, wherein the first magnetoresistance sensor further comprises a first power supply terminal vddx, a first ground terminal gndx, a first output terminal x1 and a second output terminal x2, a first end of the first magnetoresistance sensor unit and a first end of the second magnetoresistance sensor unit are connected to the first power supply terminal vddx; a first end of the third magnetoresistance sensor unit and a first end of the fourth magnetoresistance sensor unit are connected to the first ground terminal gndx; a second end of the first magnetoresistance sensor unit and a second end of the fourth magnetoresistance sensor unit are connected to the second output terminal x2; a second end of the second magnetoresistance sensor unit and a second end of the third magnetoresistance sensor unit are connected to the first output terminal x1. ​ The second magnetoresistance sensor further comprises a second power supply end vddy, a second ground end gndy, a third output end y1 and a fourth output end y2, the first end of the fifth magnetoresistance sensor unit and the first end of the sixth magnetoresistance sensor unit are connected with the second power supply end vddy; the first end of the seventh magnetoresistance sensor unit and the first end of the eighth magnetoresistance sensor unit are connected with the second ground end gndy; the second end of the fifth magnetoresistance sensor unit and the second end of the eighth magnetoresistance sensor unit are connected with the fourth output end y2; and the second end of the sixth magnetoresistance sensor unit and the second end of the seventh magnetoresistance sensor unit are connected with the third output end y1.

6. The magnetoresistance angle sensor according to claim 5, wherein, the first magnetoresistance sensor is in a quadrature arrangement, wherein the first magnetoresistance sensor unit and the third magnetoresistance sensor unit are parallel to each other and orthogonal to the second magnetoresistance sensor unit and the fourth magnetoresistance sensor unit which are parallel to each other; and the second magnetoresistance sensor is in a quadrature arrangement, wherein the fifth magnetoresistance sensor unit and the seventh magnetoresistance sensor unit are parallel to each other and orthogonal to the sixth magnetoresistance sensor unit and the eighth magnetoresistance sensor unit which are parallel to each other.

7. The magnetoresistance angle sensor according to claim 6, wherein, the first end of the magnetoresistance sensor unit is an end close to the center point A; and the second end of the magnetoresistance sensor unit is an end away from the center point A.

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