Device and method for determining orientation of magnet, and joystick

Abstract

To provide a method of determining an orientation (α, β) of a magnet which is pivotable about a reference position (Pref) having a predefined position relative to a semiconductor substrate.SOLUTION: The method comprises a) determining at least two of the following magnetic field gradients: i) a first magnetic field gradient (dBx / dx); ii) a second magnetic field gradient (dBy / dy); iii) a third magnetic field gradient (dBz / dx); and iv) a fourth magnetic field gradient (dBz / dy). The method also comprises b) determining a first angle (α) based on at least one of the magnetic field gradients, and c) determining a second angle (β) based on at least one of the magnetic field gradients. A sensor device is configured for implementing this method. A sensor system includes such a sensor device and a magnet, and is optionally connected to a joystick.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention generally relates to the field of magnetic position sensor systems, devices, and methods, and more specifically, to a magnetic position sensor system for measuring the orientation of a magnet pivotable about a fixed reference point. The present invention also relates to a position sensor system in which the magnet is connected to a joystick.

Background Art

[0002] Magnetic position sensor systems, particularly linear or angular position sensor systems, are known in the art. There are many variations of position sensor systems that address one or more of the following requirements: using a simple or inexpensive magnetic structure, using a simple or inexpensive sensor device, being able to measure over a relatively large range, being able to measure with high accuracy, requiring only simple arithmetic, being able to measure quickly, being very robust to positioning errors, being very robust to external disturbance fields, providing redundancy, being able to detect errors, being able to detect and correct errors, having a good signal-to-noise ratio (SNR), having only one degree of freedom (translation or rotation), having two degrees of freedom (e.g., one translation and one rotation, or two rotations), and so on.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In many known systems, the system has only one degree of freedom of motion, such as rotating around one axis or translating along one axis.

[0005] Magnetic position sensor systems in which the magnet has at least two degrees of freedom are also known in the art, for example, from Patent Document 1 filed on February 28, 2021, which discloses a magnet that is movable along an axis and rotatable about the axis, or from Patent Document 2, which discloses a circuit including at least one trained neural network for determining information regarding the position, orientation, or orientation of the magnet. These examples demonstrate that position sensor systems in which the magnet has at least two degrees of freedom are far more complex than systems with only one degree of freedom.

[0006] There is always room for improvement or alternatives.

[0007] An object of the embodiments of the present invention is to provide a sensor device, a position sensor system, and a method for determining the orientation (α,β) of a magnet.

[0008] Objectives of embodiments of the present invention are to provide a sensor device, a position sensor system, and a method for determining the orientation (α,β) of a cylindrical magnet that is pivotable around a fixed reference point. The fixed reference point may be located at a predetermined height above or below a semiconductor substrate ("above" means on the same side of the substrate as the magnet, and "below" means on the opposite side of the substrate from the magnet).

[0009] A particular object of embodiments of the present invention is to provide a sensor device, a position sensor system, and a method for determining the orientation (α,β) of the axes of an axially magnetized cylindrical magnet that is pivotable around a reference position located on a semiconductor substrate. [Means for solving the problem]

[0010] In a preferred embodiment, the orientation is determined in a manner that is highly robust to disturbance fields (also known as "stray fields").

[0011] A particular object of the embodiments of the present invention is to provide a joystick comprising such a magnet, the orientation of the joystick being determined with improved accuracy, for example, in a manner that is substantially insensitive to disturbance fields.

[0012] These objectives are achieved by embodiments of the present invention.

[0013] According to a first aspect, the present invention provides a sensor device for determining the orientation of an axis-forming magnet (e.g., a bipolar magnet), the sensor device comprising a semiconductor substrate including a plurality of magnetic sensors configured to determine at least two of the following magnetic field gradients: i) a first magnetic field gradient (e.g., dBx / dx) of a first magnetic field component oriented in a first direction parallel to the semiconductor substrate along a first direction; ii) a second magnetic field gradient (e.g., dBBy / dy) of a second magnetic field component oriented in a second direction parallel to the semiconductor substrate and perpendicular to the first direction along a second direction; iii) a third magnetic field gradient (e.g., dBz / dx) of a third magnetic field component oriented in a third direction perpendicular to the semiconductor substrate along a first direction; and iv) a fourth magnetic field gradient (e.g., dBz / dy) of a third magnetic field component oriented in a third direction along a second direction, the sensor device further comprising a processing circuit configured to determine a first angle (e.g., α) and a second angle (e.g., β) based on at least some of the magnetic field gradients.

[0014] In one embodiment, the sensor element is configured to determine only two magnetic field gradients, namely dBz / dx and dBz / dy, and the processing unit is configured to determine a first angle (e.g., α) as a function of only one magnetic field gradient, namely dBz / dx, and a second angle (e.g., β) as a function of only one magnetic field gradient, namely dBz / dy.

[0015] A first angle may be formed between the orthographic projection of the magnet axis A on a first virtual plane XZ parallel to a first direction X and a third direction Z, and a second angle may be formed between the orthographic projection of the magnet axis A on a second plane YZ parallel to a second direction Y and a third direction Z.

[0016] The magnet may be a cylindrical magnet.

[0017] The magnet may be a two-pole magnet, for example, a cylindrical two-pole magnet, or a two-pole bar magnet, or a two-pole spherical magnet.

[0018] The magnet may be a ring magnet magnetized in the axial direction or a disk magnet magnetized in the axial direction.

[0019] Cylindrical magnets may have an outer diameter in the range of 3.0 mm to 15.0 mm, or in the range of 4.0 mm to 12.0 mm, or in the range of 4.0 mm to 10.0 mm.

[0020] A cylindrical magnet may have a height H (axial direction) and an outer diameter D such that the ratio of this height to the outer diameter (H / D) is in the range of 20% to 100%, 20% to 80%, or 25% to 75%, for example, approximately 50%.

[0021] In one embodiment, the processing circuit is configured to determine a first angle based on at least a first magnetic field gradient (e.g., dBx / dx) and a third magnetic field gradient (e.g., dBz / dx), and to determine a second angle based only on at least a second magnetic field gradient (e.g., dBy / dy) and a fourth magnetic field gradient (e.g., dBz / dy).

[0022] In one embodiment, the processing circuit is configured to determine a first angle based only on a first magnetic field gradient (e.g., dBx / dx) and a third magnetic field gradient (e.g., dBz / dx), and to determine a second angle based only on a second magnetic field gradient (e.g., dBy / dy) and a fourth magnetic field gradient (e.g., dBz / dy).

[0023] In one embodiment, the plurality of magnetic sensors includes a first sensor, a second sensor, a third sensor, and a fourth sensor. The first sensor located at the first sensor location and the second sensor located at the second sensor location are located on a first virtual line oriented in a first direction and are separated from each other by a first distance. The first sensor is configured to measure a first magnetic field component oriented in the first direction and a second magnetic field component oriented in a third direction. The second sensor is configured to measure a third magnetic field component oriented in the first direction and a fourth magnetic field component oriented in a third direction. The third sensor located at the third sensor location and the fourth sensor located at the fourth sensor location are located on a second virtual line oriented in a second direction and are separated from each other by a second distance. The third sensor is configured to measure a fifth magnetic field component oriented in the second direction and a sixth magnetic field component oriented in a third direction. The fourth sensor is configured to measure a seventh magnetic field component oriented in the first direction and an eighth magnetic field component oriented in a third direction.

[0024] Using such a configuration, the first magnetic field gradient (e.g., dBx / dx) may be based on the difference between the first magnetic field component and the third magnetic field component. The second magnetic field gradient (e.g., dBz / dx) may be based on the difference between the second magnetic field component and the fourth magnetic field component. The third magnetic field gradient (e.g., dBy / dy) may be based on the difference between the fifth magnetic field component and the seventh magnetic field component. The fourth magnetic field gradient (e.g., dBz / dy) may be based on the difference between the sixth magnetic field component and the eighth magnetic field component.

[0025] In an embodiment, the first angle (α) is given by the equation α = K1 * atan2(dBz / dx, dBx / dx) where α is the first angle, atan2() is the arctangent function of two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, and K1 is a first predetermined constant. The second angle (β) is given by the equation β = K2 * atan2(dBz / dy, dBy / dy) determined according to the formula, where β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 is the second predetermined constant.

[0026] In an embodiment, the first angle (α) is given by the formula α = K1 * atan2(K3 * dBz / dx, dBx / dx) determined according to the formula, where α is the first angle, atan2() is the arctangent function of two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, K1 and K3 are predetermined constants, and the second angle (β) is given by the formula: β = K2 * atan2(K4 * dBz / dy, dBy / dy) determined according to the formula, where β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 and K4 are predetermined constants.

[0027] In one embodiment, the magnet is movable such that the virtual axis of the magnet is pivotable about a reference point (e.g., Pref) having a predetermined position with respect to the semiconductor substrate.

[0028] In one embodiment, the reference point (e.g., Pref) is located on the semiconductor substrate and thus in the same plane as the sensor.

[0029] In one embodiment, the reference point (e.g., Pref) is located on an imaginary axis perpendicular to the semiconductor substrate at a predetermined non-zero distance (e.g., dref) from the semiconductor substrate, either above or below the semiconductor substrate. The reference point and the magnet may be located on the same side or opposite sides of the semiconductor substrate. The reference point may be located between the substrate and the magnet when the magnet is in its neutral position (i.e., when its axis is oriented perpendicular to the semiconductor substrate) or within the space defined by the magnet (when in its neutral position), or the magnet (when in its neutral position) may be located between the reference position and the semiconductor substrate.

[0030] In certain embodiments, the ratio of the distance "dref" to the (axial) height H of the magnet (dref / H) may be a value in the range of 50% to 200%, or 50% to 150%, or 75% to 125%.

[0031] In one embodiment, the first distance (e.g., ΔX) between the first sensor location and the second sensor location is substantially equal to the second distance (e.g., ΔY) between the third sensor location and the fourth sensor location. In this embodiment, the sensors may be located on a virtual circle. The reference point may be located at the center of this circle, or it may be located at a predetermined non-zero distance from the substrate on a virtual line perpendicular to the substrate and passing through the center of the circle.

[0032] In one embodiment, the first distance (e.g., ΔX) between the first sensor location and the second sensor location is at least 5% greater than or at least 5% less than the second distance (e.g., ΔY) between the third sensor location and the fourth sensor location. In this embodiment, the sensors may be located on a virtual ellipsoid. The reference point may be located at the center of this ellipsoid, or it may be located at a predetermined non-zero distance from the substrate on a virtual line perpendicular to the substrate and passing through the center of the ellipsoid.

[0033] In one embodiment, each of the four sensors comprises an integrated magnetic centrifuge and two horizontal Hall elements.

[0034] The integrated magnetic centrifuge (also known as an "integrated flux centrifuge") may have a disk shape with a diameter in the range of 150 μm to 250 μm, for example, in the range of 170 μm to 230 μm, for example, equal to approximately 200 μm.

[0035] In one embodiment, the first sensor includes a first integrated magnetic centrifuge and first and second horizontal Hall elements located opposite the first IMC on a first virtual line oriented in a first direction; the second sensor includes a second integrated magnetic centrifuge and third and fourth horizontal Hall elements located on a first virtual line opposite the second IMC; the third sensor includes a third integrated magnetic centrifuge and fifth and sixth horizontal Hall elements located opposite the third IMC on a second virtual line oriented in a second direction; and the fourth sensor includes a fourth integrated magnetic centrifuge and seventh and eighth horizontal Hall elements located on a second virtual line opposite the fourth IMC.

[0036] An example of such an arrangement is shown in Figure 5.

[0037] In one embodiment, each of the four sensors includes a horizontal Hall element and a vertical Hall element. In this embodiment, the sensor device preferably does not include a magnetic flux centrifuge (IMC).

[0038] In one embodiment, each of the four sensors includes a horizontal Hall element and at least one magnetoresistive sensor element. In this embodiment, the sensor device preferably does not include a magnetic flux centrifuge (IMC).

[0039] In one embodiment, the first sensor includes a first horizontal Hall element and a first vertical Hall element, the second sensor includes a second horizontal Hall element and a second vertical Hall element, each of the first and second vertical Hall elements having an axis of maximum sensitivity oriented in a first direction, the third sensor includes a third horizontal Hall element and a third vertical Hall element, and the fourth sensor includes a fourth horizontal Hall element and a fourth vertical Hall element, each of the third and fourth vertical Hall elements having an axis of maximum sensitivity oriented in a second direction.

[0040] In one embodiment, the processing circuit is integrated with the semiconductor substrate. Therefore, in this embodiment, the sensor element and the processing circuit are integrated on a single substrate.

[0041] According to a second aspect, the present invention also provides a position sensor system comprising a sensor device according to the first aspect and a magnet pivotable about a reference point (e.g., Pref) having a predetermined position relative to a semiconductor substrate. This means that the magnet is movable so as to rotate about the predetermined reference position, for example, as shown in Figure 1. The magnet may have a cylindrical or spherical shape and may be rotatable about its own axis, but such rotation does not change the magnetic field line.

[0042] The magnet may be, for example, a cylindrical, rod-shaped, or spherical two-pole magnet.

[0043] In one embodiment, the system further comprises a joystick connected to a magnet.

[0044] According to a third aspect, the present invention also provides a method for determining the orientation (for example, using two angles α and β) of a pivotable magnet about a reference point (e.g., Pref) having a predetermined position on a semiconductor substrate, wherein the method is a) Magnetic field gradient: i) The first magnetic field gradient (e.g., dBx / dx) of the first magnetic field component oriented in the first direction parallel to the semiconductor substrate along the first direction, ii) The second magnetic field gradient (e.g., dBy / dy) of the second magnetic field component oriented in the second direction parallel to the semiconductor substrate and perpendicular to the first direction along the second direction, iii) The third magnetic field gradient (e.g., dBz / dx) of the third magnetic field component oriented in the third direction perpendicular to the semiconductor substrate along the first direction, and iv) The third magnetic field component oriented in the third direction along the second direction. a) determining at least two of the fourth magnetic field gradients (e.g., dBz / dy), b) determining a first angle formed between the orthographic projection of the magnet axis on a first virtual plane (e.g., XZ) parallel to a first direction (e.g., X) and a third direction (e.g., Z) based on at least some of the magnetic field gradients, and c) determining a second angle formed between the orthographic projection of the magnet axis on a second virtual plane (e.g., YZ) parallel to a second direction and a third direction, based on at least some of the magnetic field gradients.

[0045] In one embodiment, step a) includes determining only two magnetic field gradients, namely dBz / dx and dBz / dy; step b) includes determining a first angle (e.g., α) as a function of only one magnetic field gradient, namely dBz / dx; and step c) includes determining a second angle (e.g., β) as a function of only one magnetic field gradient, namely dBz / dy.

[0046] In one embodiment, the first angle is determined based on at least a first magnetic field gradient (e.g., dBx / dx) and a third magnetic field gradient (e.g., dBz / dx), and the second angle is determined based on at least a second magnetic field gradient (e.g., dBBy / dy) and a fourth magnetic field gradient (e.g., dBz / dy).

[0047] In one embodiment, the first angle is determined based only on a first magnetic field gradient (e.g., dBx / dx) and a third magnetic field gradient (e.g., dBz / dx), and the second angle is determined based only on a second magnetic field gradient (e.g., dBBy / dy) and a fourth magnetic field gradient (e.g., dBz / dy).

[0048] In this embodiment, the first angle is given by the formula α = K1 * atan2(dBz / dx, dBx / dx) Determined according to the formula, where α is the first angle, atan2() is the arctangent function of the two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, K1 is a first predetermined constant, and the second angle is given by the formula β = K² * atan² (dBz / dy, dBy / dy) It is determined according to the formula, where β is the second angle, atan2() is the arctangent function of the two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 is a second predetermined constant.

[0049] In this embodiment, the first angle is given by the formula α = K1 * atan2(K3 * dBz / dx, dBx / dx) Determined according to the formula, where α is the first angle, atan2() is the arctangent function of the two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, K1 and K3 are predetermined constants, and the second angle is given by the formula β = K² * atan² (K⁴ * dBz / dy, dBy / dy) It is determined according to the formula, where β is the second angle, atan2() is the arctangent function of the two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 and K4 are predetermined constants.

[0050] Specific and preferred embodiments of the present invention are described in the attached independent and dependent claims. Features from the dependent claims are not merely expressly described in the claims, but may be combined as appropriate with the features of the independent claims and other dependent claims.

[0051] These and other aspects of the present invention will be evident from and clarified by reference to the embodiments described below. [Brief explanation of the drawing]

[0052] [Figure 1] This is a schematic diagram of a magnetic position sensor system that includes a magnet magnetized in the axial direction, movable relative to a sensor device, and having at least two degrees of freedom. [Figure 2] This paper shows how the random orientation of a line segment [CP] can be represented by two angles α and β. [Figure 3] This is a schematic block diagram of a sensor structure that may be used in embodiments of the present invention, the sensor structure comprising a first sensor at a first location X1 and a second sensor at a second location X2 along the X axis, each sensor comprising an integrated magnetic centrifuge (IMC) and two horizontal Hall elements positioned on the opposite side of the IMC, and the in-plane magnetic field gradient (dBx / dx) and out-of-plane magnetic field gradient (dBz / dx) can be measured by this sensor structure. [Figure 4(a)] This is a schematic diagram of a cylindrical magnet having an axis that intersects a semiconductor substrate at a predetermined reference position, where the sensor or sensor structure is located at the reference position. The magnetic field lines passing through the sensor location have the same orientation as the mechanical angle of the axis, and the distance between the sensor and the magnet is independent of the axis orientation. [Figure 4(b)] This is a schematic diagram of a cylindrical magnet having an axis that intersects a semiconductor substrate at a predetermined reference position, where the sensor or sensor structure is located at the reference position. The magnetic field lines passing through the sensor location have the same orientation as the mechanical angle of the axis, and the distance between the sensor and the magnet is independent of the axis orientation. [Figure 4(c)] This is a schematic diagram of a cylindrical magnet having an axis that intersects a semiconductor substrate at a predetermined reference position. The semiconductor substrate includes multiple sensors or sensor structures located at sensor positions spaced apart from the reference position. The orientation of the magnetic field lines at the multiple sensor locations is not the same as the orientation of the axis, and the distance between each sensor location and the magnet is not constant but depends on the orientation of the axis. [Figure 4(d)] This is a schematic diagram of a cylindrical magnet having an axis that intersects a semiconductor substrate at a predetermined reference position. The semiconductor substrate includes multiple sensors or sensor structures located at sensor positions spaced apart from the reference position. The orientation of the magnetic field lines at the multiple sensor locations is not the same as the orientation of the axis, and the distance between each sensor location and the magnet is not constant but depends on the orientation of the axis. [Figure 5] This is a schematic diagram of the first sensor device proposed by the present invention. [Figure 6] This is a schematic diagram of another sensor device proposed by the present invention. [Figure 7(a)] The simulation results of the system proposed by the present invention are shown. [Figure 7(b)] The simulation results of the system proposed by the present invention are shown. [Figure 7(c)] The simulation results of the system proposed by the present invention are shown. [Figure 7(d)] The simulation results of the system proposed by the present invention are shown. [Figure 7(e)]The simulation results of the system proposed by the present invention are shown. [Figure 8(a)] The simulation results of another system proposed by the present invention are shown below. [Figure 8(b)] The simulation results of another system proposed by the present invention are shown below. [Figure 8(c)] The simulation results of another system proposed by the present invention are shown below. [Figure 8(d)] The simulation results of another system proposed by the present invention are shown below. [Figure 8(e)] The simulation results of another system proposed by the present invention are shown below. [Figure 9] An electrical block diagram of a circuit that may be used in the position sensor device proposed by the present invention is shown. [Figure 10] A flowchart illustrating the method for determining two angles α and β corresponding to the orientation of the magnet axis as proposed by this invention is shown. [Figure 11] A modified version of the sensor system shown in Figure 1 is available, in which the magnet is pivotable around a reference point located at a predetermined distance "dref" above the substrate. [Modes for carrying out the invention]

[0053] The drawings are schematic and non-limiting. In the drawings, the size of some elements may be exaggerated and may not be drawn to scale for illustrative purposes. Any reference numerals in the claims should not be construed as limiting. In different drawings, the same reference numeral refers to the same or similar elements.

[0054] The present invention will be described with respect to specific embodiments and with reference to specific drawings, but will not be limited thereto, and will be limited only by the claims.

[0055] The terms first, second and similar in this description and claims are used to distinguish similar elements and are not necessarily used to describe order in any temporal, spatial, sequential, or any other way. It should be understood that the terms used in this manner are interchangeable under appropriate circumstances, and that embodiments of the invention described herein may operate in any order other than those described or illustrated herein.

[0056] Terms such as "top," "bottom," etc., used in this description and claims are for descriptive purposes only and are not necessarily used to describe relative positions. It should be understood that these terms are interchangeable under appropriate circumstances, and that embodiments of the invention described herein may operate in orientations other than those described or illustrated herein.

[0057] It should be noted that the term “equipped with” as used in the claims should not be construed as being limited to the means subsequently enumerated, and does not exclude other elements or steps. Therefore, it is construed as identifying the presence of the described features, integers, steps, or components, as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Accordingly, the scope of the expression “device comprising means A and B” should not be limited to a device consisting solely of components A and B. This means, with respect to the present invention, that the relevant components of the device are only A and B.

[0058] Throughout this specification, “one embodiment” or “embodiment” means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of the present invention. Therefore, occurrences of the phrase “in one embodiment” or “in an embodiment” in various parts of this specification do not necessarily all refer to the same embodiment, but may refer to the same embodiment. Furthermore, particular features, structures, or characteristics can be combined in one or more embodiments in any suitable manner, as will be apparent to those skilled in the art from this disclosure.

[0059] Similarly, in the description of exemplary embodiments of the present invention, various features of the invention may be grouped into a single embodiment, drawing, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than are explicitly enumerated in each claim. Rather, as the following claims demonstrate, the embodiments of the invention are not all features of a single, aforementioned disclosed embodiment. Therefore, the claims following the detailed description are explicitly incorporated into this detailed description, and each claim exists independently as a distinct embodiment of the invention.

[0060] Furthermore, some embodiments described herein include some other features included in other embodiments, and do not include other features, but combinations of features of different embodiments mean that they are within the scope of the invention and form different embodiments, as will be understood by those skilled in the art. For example, in the following claims, any combination of any of the embodiments described in the claims may be used.

[0061] Numerous specific details are described herein. However, it should be understood that embodiments of the present invention may be carried out without these specific details. In other cases, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0062] In this document, unless otherwise explicitly stated, the terms “magnetic sensor device” or “sensor device” refer to a device comprising at least one “magnetic sensor” or at least one magnetic “sensor element” integrated on a semiconductor substrate, preferably. The sensor device may, but is not absolutely necessary, be contained in a package also called a “chip.”

[0063] In this document, the terms “sensor element,” “magnetic sensor element,” or “magnetic sensor” may refer to a component or group of components, subcircuit, or structure capable of measuring a magnetic quantity, such as a magnetoresistive element, GMR element, XMR element, horizontal Hall plate, vertical Hall plate, Wheatstone bridge including at least one (preferably four) magnetoresistive elements, or a combination thereof.

[0064] In certain embodiments of the present invention, the terms “magnetic sensor” or “magnetic sensor structure” may refer to an arrangement comprising one or more integrated magnetic centrifuges (IMCs), also known as integrated flux centrifuges, and one or more horizontal Hall elements positioned near the perimeter of a disk-shaped IMC, for example, two horizontal Hall elements arranged at 180° intervals from each other, or four horizontal Hall elements arranged at 90° intervals from each other.

[0065] In this document, the expressions "in-plane component of the magnetic field vector" and "projection of the magnetic field vector on the sensor surface" mean the same thing. If the sensor device is a semiconductor substrate, or includes a semiconductor substrate, this also means "magnetic field component parallel to the semiconductor plane." These components may be labeled Bx and By.

[0066] In this document, the expressions "out-of-plane component of a vector," "Z component of a vector," and "projection of a vector on an axis perpendicular to the sensor surface" mean the same thing. This component may also be labeled Bz.

[0067] Embodiments of the present invention are typically described using a Cartesian coordinate system fixed to a sensor device and having three axes X, Y, and Z, where the X and Y axes are parallel to the substrate and the Z axis is perpendicular to the substrate.

[0068] In this document, the terms "spatial derivative," "derivative," "spatial gradient," or "gradient" are used synonymously. In the context of this invention, the gradient is typically determined as the difference between two values ​​measured at two locations spaced apart along a particular direction. Theoretically, the gradient is typically calculated as the difference between the two values ​​divided by the distance between the sensor locations, but in practice, the division by distance is often omitted because the measured signal also needs to be scaled.

[0069] In this application, horizontal hole plates are typically referred to as H1, H2, etc., and signals from these horizontal hole plates are typically referred to as h1, h2, etc., vertical hole plates are typically referred to as V1, V2, etc., and signals from these vertical hole plates are typically referred to as v1, v2, etc.

[0070] In the context of this invention, the formulas arctan(x,y), atan2(x,y), and arccot(y / x) are considered equivalent.

[0071] The present invention relates to a magnetic position sensor system, method, and device for measuring the orientation of a pivotable magnet about a fixed reference point "Pref". This fixed reference point may be located on a semiconductor substrate or at a predetermined distance "dref" above or below the semiconductor substrate. The magnet may be connected to a joystick (not shown).

[0072] In a preferred embodiment, the system has improved accuracy, for example, because it is less sensitive to disturbances.

[0073] Refer to the drawing.

[0074] Figure 1 is a schematic diagram of a magnetic position sensor system 100, which includes a cylindrical magnet 101 and a sensor device 102.

[0075] The sensor device 102 includes a semiconductor substrate (not shown in Figure 1). A coordinate system having three orthogonal axes X, Y, and Z is connected to the semiconductor substrate such that axes X and Y are parallel to the semiconductor substrate and axis Z is orthogonal to the semiconductor substrate.

[0076] The magnet 101 shown in Figure 1 is a cylindrical magnet, more specifically, a magnet magnetized in the axial direction. The magnet has a virtual axis "A" that intersects the semiconductor substrate and a fixed reference point "Pref", and can rotate in various directions. Since the distance between the magnet 101 and the reference point "Pref" is constant, the system has two degrees of freedom. The task of the sensor device 102 is to determine the orientation of the magnet.

[0077] The orientation can be uniquely defined, for example, by two angles φ and ψ, where φ is the negative or positive angle with respect to the Z axis of the orthographic projection of axis A in the YZ plane, and ψ is the negative or positive angle with respect to the Z axis of the orthographic projection of axis A in the XZ plane. In the example shown, if axis A of the magnet is oriented perpendicular to the semiconductor substrate, the magnetic field vector B at the intersection of axis A and the semiconductor substrate is oriented in the negative Z direction, with φ=0° and ψ=0°. It is preferable that the magnet is movable in the range of φ at least -30° to +30° and ψ in the range of 30° to +30°, although of course larger ranges, such as ±40°, or ±50°, or ±60°, are also conceivable. However, specifying the orientation of the magnet 101 by angles φ and ψ is not the only possible method.

[0078] Figure 2 shows another way of defining the orientation of a vector of constant length [CP], starting from a reference point "C" and ending at a point "P" on an imaginary sphere. The vector [CP] is not shown, but its first orthographic projection [CA] onto the plane XZ is shown, and its second orthographic projection [CB] onto the plane YZ is shown. The orientation of axis A passing through points C and P can also be defined by a first angle α between the positive X-axis and vector [CA], and a second angle β between the positive Y-axis and vector [CB]. As an example, when the magnet axis is oriented perpendicular to the plane XY (i.e., perpendicular to the semiconductor substrate), it is also called the "neutral position," with α=90° and β=90°. This corresponds to the orientation of φ=0° and ψ=0° mentioned above.

[0079] The following formula applies: Bx = B * cos(α) * sin(β) [1] By = B * cos(β) * sin(α) [2] Bz = B * sin(β) * sin(α) [3]

[0080] The division of [3] and [1] yields the following: (Bz / Bx)=tan(α) [4] (Bz / By)=tan(β) [5]

[0081] In the equation, Bx is the magnetic field component oriented in the X direction, By is the magnetic field component oriented in the Y direction, Bz is the magnetic field component oriented in the Z direction, and B is the magnitude of the magnetic field vector.

[0082] In a preferred embodiment, angles α and β are values ​​within the range of 90°±30°, or within the range of 90°±40°, or within the range of 90°±50°, or within the range of 90°±60°.

[0083] Figure 3 shows a semiconductor substrate including a first sensor (or sensor structure) S1 located at a first sensor location X1 on the X-axis, and a second sensor (or sensor structure) S2 located at a second sensor location X2 on the X-axis, spaced apart from X1. Each of the first and second sensors S1 and S2 includes a disk-shaped integrated magnetic centrifuge (IMC) and two horizontal Hall elements positioned on the X-axis opposite the IMC. The first sensor S1 includes a first horizontal Hall element H1 configured to provide a first signal h1 and a second horizontal Hall element H2 configured to provide a second signal h2. The second sensor S2 includes a third horizontal Hall element H3 configured to provide a third signal h3 and a fourth horizontal Hall element H4 configured to provide a fourth signal h4.

[0084] To understand the present invention, it is sufficient to know that by combining the signals h1 and h2 from the first sensor S1, both the in-plane magnetic field component Bx1 (parallel to the semiconductor substrate) and the out-of-plane magnetic field component Bz1 (perpendicular to the semiconductor substrate) can be determined. More specifically, the in-plane magnetic field component Bx1 is parallel to the X-axis and can be calculated by subtracting the signals h1 and h2, while the out-of-plane magnetic field component Bz1 is parallel to the Z-axis and can be calculated by adding the signals h1 and h2. This can be expressed mathematically as follows.

[0085] Bx1=(h2-h1) [6] Bz1=(h2+h1) [7]

[0086] Similarly, the in-plane magnetic field component Bx2 and the out-of-plane magnetic field component Bz2 at the second sensor location X2 can be determined, for example, according to the following equation.

[0087] Bx2=(h4-h3) [8] Bz²=(h⁴+h³) [9]

[0088] From these values, the in-plane magnetic field gradient dBx / dx and the out-of-plane magnetic field gradient dBz / dx can be determined, for example, according to the following equation.

[0089] ΔBx / Δx=Bx²-Bx¹

[10] ΔBz / Δx=Bz2-Bz1

[11]

[0090] Although division by "Δx" is generally omitted because the distance is constant and the value obtained from the Hall element still needs to be scaled, the notation ΔBz / Δx (or dBz / dx) is useful in this application because it not only indicates that the difference between two Bz values ​​is taken, but also indicates the direction along which it lies, such as the X direction in the case of Δx. As is known in the art, gradient signals are very insensitive to disturbance fields.

[0091] The sensor device (not shown in Figure 3, see, for example, Figure 6) has two sensors S1 and S2 separated by a distance ΔX, where the first sensor S1 includes one horizontal Hall element H1 and one vertical Hall element V1 with the axis of maximum sensitivity oriented in the X direction, and the second sensor S2 includes one horizontal Hall element H2 and one vertical Hall element V2 with the axis of maximum sensitivity oriented in the X direction, and can measure Bx1, Bz1 and Bx2 and Bz2 respectively, and can determine two magnetic field gradients dBx / dx and dBz / dx. If v1 is the signal obtained from V1, v2 is the signal obtained from V2, h1 is the signal obtained from H1, and h2 is the signal obtained from H2, then dBx / dx can be calculated as (v2-v1) and dBz / dx can be calculated as (h2-h1).

[0092] Figures 4(a) to 4(d) are schematic diagrams of a cylindrical magnet having a virtual axis "A" that intersects a semiconductor substrate (roughly shown by a dotted line) at a predetermined position "Pref". Axis "A" is pivotable around the reference point "Pref". To avoid overloading the drawings, only movements parallel to the XZ plane are shown.

[0093] In Figures 4(a) and 4(b), the sensor (roughly shown as a black square) is located at the reference position "Pref". As can be seen, the magnetic field lines passing through the sensor location have the same orientation as the mechanical orientation of the magnet axis "A", and the distance "g" between the sensor and the magnet is independent of the axis orientation.

[0094] In Figures 4(c) and 4(d), the semiconductor substrate includes multiple sensors spaced apart by a distance ΔX, with the reference position "Pref" preferably located in the center between the sensor locations. As can be seen, the orientation of the magnetic field lines at the multiple sensor locations is no longer identical to the orientation of axis A, and the distance between each sensor location and the magnet is no longer constant but depends on the orientation of axis "A".

[0095] To the best of the inventors' knowledge, there is no general analytical formula or relationship between the mechanical tilt angle of axis A and the magnetic field components (Bx, By, Bz) at two sensor locations, much less the relationship between the mechanical tilt angle and the magnetic field gradient dBx / dx, as obtained from signals from two sensors located at a distance of Δx / 2 from a reference point. The inventors began a research project to investigate this relationship. It was anticipated that this relationship would be highly nonlinear and mathematically very difficult to explain.

[0096] Figure 5 is a schematic diagram of the first sensor device 500 proposed by the present invention.

[0097] Sensor device 500 is, i) A first magnetic field gradient dBx / dx of a first magnetic field component Bx oriented in a first direction X parallel to the semiconductor substrate, along the first direction X, ii) The second magnetic field gradient dBy / dy of the second magnetic field component oriented in the second direction Y, parallel to the semiconductor substrate and perpendicular to the first direction X, along the second direction Y, iii) The third magnetic field gradient dBz / dx of the third magnetic field component Bz, which is oriented in a third direction Z perpendicular to the semiconductor substrate along the first direction X, iv) A semiconductor substrate comprising a plurality of magnetic sensors S1, S2, S3, S4 configured to determine a fourth magnetic field gradient dBz / dy of a third magnetic field component Bz oriented in a third direction Z along a second direction Y.

[0098] The sensor device 500 further comprises a processing circuit (not shown in Figure 5, see, for example, Figure 9) configured to determine two angles, e.g., φ and ψ, as shown in Figure 1, or two angles, e.g., α and β, as shown in Figure 2, which define the orientation of axis A of a magnet, e.g., a magnet pivotable around a fixed reference point, based on these magnetic field gradients dBx / dx, dBy / dy, dBz / dx, dBz / dy.

[0099] Furthermore, the inventors surprisingly discovered that, even in the presence of disturbances, it is possible to define and calculate such angles based on these four magnetic field gradients using analytical methods and with relatively good approximations, for example, with an absolute error of less than ±10°. This was unexpected.

[0100] The inventors also found that this accuracy can be further improved through post-processing, for example, by remapping the angles calculated using two piecewise linear approximation functions, one for each angle (i.e., reducing the absolute error to less than ±5° or less than ±3°).

[0101] The processing circuit may be configured to determine a first angle α formed between the orthographic projection of the magnet axis A on a first virtual plane XZ based on a first magnetic field gradient dBx / dx and a third magnetic field gradient dBz / dx, where the virtual plane XZ is parallel to the first direction X and the third direction Z. The processing circuit may also be configured to determine a second angle β formed between the orthographic projection of the magnet axis A on a second virtual plane YZ based on a second magnetic field gradient dBBy / dy and a fourth magnetic field gradient dBz / dy, where the virtual plane YZ is parallel to the second direction Y and the third direction Z.

[0102] By using these angles α and β (shown in Figure 2) to determine the orientation of axis A of the magnet, we found that the angle can be calculated using a relatively simple mathematical formula.

[0103] The multiple magnetic sensors may include a first sensor S1, a second sensor S2, a third sensor S3, and a fourth sensor S4.

[0104] The first sensor S1 may be located at a first sensor location, and the second sensor S2 may be located at a second sensor location, both located on a first imaginary line oriented in a first direction X, and separated from each other by a first non-zero distance ΔX. The first sensor S1 may be configured to measure a first magnetic field component Bx1 oriented in the first direction X and a second magnetic field component Bz1 oriented in a third direction Z. The second sensor S2 may be configured to measure a third magnetic field component Bx2 oriented in the first direction X and a fourth magnetic field component Bz2 oriented in a third direction Z.

[0105] The third sensor S3 may be located at the third sensor location, and the fourth sensor S4 may be located at the fourth sensor location, both located on a second imaginary line oriented in the second direction Y, and separated from each other by a second non-zero distance ΔY. The third sensor S3 may be configured to measure a fifth magnetic field component By1 oriented in the second direction Y and a sixth magnetic field component Bz3 oriented in the third direction Z. The fourth sensor S4 may be configured to measure a seventh magnetic field component By2 oriented in the first direction X and an eighth magnetic field component Bz4 oriented in the third direction Z.

[0106] The sensor device may be further configured to determine a first magnetic field gradient dBx / dx based on the difference between the magnetic field components of a first Bx1 and a third Bx2, a second magnetic field gradient dBz / dx based on the difference between the magnetic field components of a second Bz1 and a fourth Bz2, a third magnetic field gradient dBBy / dy based on the difference between the magnetic field components of a fifth By1 and a seventh By2, and a fourth magnetic field gradient dBz / dy based on the difference between the magnetic field components of a sixth Bz3 and an eighth Bz4.

[0107] In one embodiment, distance ΔY is equal to distance ΔX, in which case the four sensor locations are preferably located on a circle, and the reference point "Pref" is preferably located at the center of this circle.

[0108] In another embodiment, the distance ΔY is different from ΔX, for example, at least 5% greater than or less than ΔY, in which case the four sensor locations are preferably located on an ellipse, and the reference point "Pref" is preferably located at the center of this ellipse. Using such an embodiment, the size of the semiconductor substrate can be reduced, thus increasing compactness and reducing costs. This may be particularly suitable for joystick applications where the "handle" (e.g., having at least three or four positions) is movable over a larger range parallel to the YZ plane (e.g., having only two positions) compared to a range parallel to the XZ plane (e.g., having at least three or four positions).

[0109] In the example shown in Figure 5, each of the four sensors S1 to S4 comprises an integrated magnetic centrifuge (IMC) and two horizontal Hall elements positioned at 180° intervals near the IMC.

[0110] More specifically, the first sensor S1 includes a first integrated magnetic centrifuge IMC1 and first and second horizontal Hall elements H1 and H2 located on the opposite side of the first IMC on a first virtual line oriented in a first direction X. The second sensor S2 includes a second integrated magnetic centrifuge IMC2 and third and fourth horizontal Hall elements H3 and H4 located on the first virtual line opposite the second IMC. The third sensor S3 includes a third integrated magnetic centrifuge IMC3 and fifth and sixth horizontal Hall elements H5 and H6 located on the opposite side of the third IMC on a second virtual line oriented in a second direction Y. The fourth sensor S4 includes a fourth integrated magnetic centrifuge IMC4 and seventh and eighth horizontal Hall elements H7 and H8 located on the second virtual line opposite the fourth IMC.

[0111] The integrated magnetic centrifuge (also known as an "integrated flux centrifuge") may have a disk shape with a diameter in the range of 150 μm to 250 μm, for example, in the range of 170 μm to 230 μm, for example, equal to approximately 200 μm.

[0112] If h1 to h8 are signals provided by horizontal Hall elements H1 to H8 respectively, the four gradient values ​​may be calculated according to the following formula.

[0113] gr1=(dBx / dx)=Bx2-Bx1=(h4-h3)-(h2-h1)

[11] gr2=(dBz / dx)=Bz2-Bz1=(h4+h3)-(h2+h1)

[12] gr3=(dBy / dy)=By4-By3=(h8-h7)-(h6-h5)

[13] gr4=(dBz / dy)=Bz4-Bz3=(h8+h7)-(h6+h5)

[14]

[0114] To our surprise, the inventors have found that the first angle α can be very well approximated by the following extremely simple formula.

[0115] α = K1 * atan2(gr2,gr1) [15a]

[0116] Furthermore, the second angle β can be approximated very well by the following extremely simple equation.

[0117] β = K² * atan²(gr₄,gr₃) [16a]

[0118] Since both angles α and β are calculated as functions of the magnetic gradient, these angles are very insensitive to disturbances. Furthermore, since the angles are calculated based on the ratio of the two gradients, these angles are also very insensitive to aging effects such as temperature changes and / or demagnetization of the magnet.

[0119] The values ​​of K1 and K2 may be determined by simulation or calibration and stored in the non-volatile memory of the sensor device. The values ​​of K1 and K2 may depend on the size of the magnet (diameter, height), the distance between the sensors Δx and Δy, and the distance "g" between the magnet and the reference point "Pref".

[0120] However, the present invention is not limited thereto, and the following formula may also be used.

[0121] α = K1 * atan2(K3 * gr2, gr1) [15b] β = K² * atan² (K₄ * gr₄, gr₃) [16b]

[0122] In the equations, K3 and K4 are predetermined constants, further explained in Figures 7(c) and 8(c). Equations [15b] and [16b] may provide more accurate results when Δx is different from Δy. Naturally, many variations of the equations are possible, for example,

[0123] α = K1 * atan2(gr2 / K5,gr1) [15c], or α = K1 * atan2(gr2, K6 * gr1) [15d], or α = K1 * atan2(gr2, gr1 / K7) [15e] is also acceptable.

[0124] In the formula, K5, K6, and K7 are predetermined constants. A similar modification is possible for formula [16b].

[0125] Figure 6 is a schematic diagram of another sensor device 600 proposed by the present invention, which can be seen as a modification of the sensor device of Figure 5. The main difference is that each sensor comprises one horizontal Hall element and one vertical Hall element. Others are also applicable here as needed.

[0126] More specifically, in the example in Figure 6, the first sensor S1 includes a first horizontal Hall element H1 and a first vertical Hall element V1, the second sensor S2 includes a second horizontal Hall element H2 and a second vertical Hall element V2, and each of the first and second vertical Hall elements V1 and V2 has an axis of maximum sensitivity oriented in a first direction X. Similarly, the third sensor S3 includes a third horizontal Hall element H3 and a third vertical Hall element V3, and the fourth sensor S4 includes a fourth horizontal Hall element H4 and a fourth vertical Hall element V4, and each of the third and fourth vertical Hall elements V3 and V4 has an axis of maximum sensitivity oriented in a second direction Y.

[0127] If h1 to h4 are signals provided by horizontal Hall elements H1 to H4 and v1 to v4 are signals provided by vertical Hall elements V1 to V4, then the first and second angles α and β may be calculated according to the following series of equations.

[0128] gr1=(dBx / dx)=Bx2-Bx1=(v2-v1)

[17] gr2=(dBz / dx)=Bz2-Bz1=(h2-h1)

[18] gr3=(dBy / dy)=By4-By3=(v4-v3)

[19] gr4=(dBz / dy)=Bz4-Bz3=(h4-h3)

[20] α = K1 * atan2(gr2,gr1) [21a] β = K² * atan²(gr₄,gr₃) [22a]

[0129] Alternatively, the following formula can be used:

[0130] α = K1 * atan2(K3 * gr2, gr1) [21b] β = K² * atan² (K₄ * gr₄, gr₃) [22b]

[0131] This can yield more accurate results when Δx is different from Δy.

[0132] In the modified version shown in Figure 6, the sensor device does not include a vertical Hall element, but instead includes a magnetoresistive element.

[0133] In another variation, the vertical Hall element in Figure 6 is omitted, so the sensor device in Figure 6 includes only four horizontal Hall elements.

[0134] Figure 7(a) shows an exemplary sensor system 700, comprising a cylindrical magnet having a diameter D=4 mm and a height H=4 mm, mounted at a distance g=3 mm from a reference point located on a semiconductor substrate, between two sensors spaced approximately 1.7 mm apart, each comprising an IMC and two horizontal Hall elements (e.g., illustrated in Figure 3 or Figure 5), each having a diameter of approximately 190 μm.

[0135] Figures 7(b) to 7(e) show the simulation results of this sensor system.

[0136] Figure 7(b) shows plots of the waveforms of the magnetic field components Bx and Bz as functions of the mechanical angle α (as shown in Figure 2) measured by a sensor located at the reference position "Pref," as shown in Figures 4(a) and 4(b). This plot also shows the waveform of the magnetic field magnitude |B| calculated as the sum of squares of these components sqr(Bx) + sqr(Bz). As can be seen, this value is substantially constant.

[0137] Figure 7(c) shows plots of the waveforms of the magnetic field gradients gr2 = dBz / dx and gr1 = dBx / dx as functions of the mechanical angle α, as can be derived from signals measured by two sensors located opposite the reference position "Pref", as shown in Figures 4(c) and 4(d), and therefore as can be determined by the sensor device, for example, as shown in Figure 5 or 6. The plot in Figure 7(b) also shows the waveform of |dB| calculated as the sum of squares of these gradients sqr(dBx / dx) + sqr(dBz / dx). As can be seen, this value is rather constant, but not perfectly constant, meaning that the gradient signals gr1 and gr2 are not perfectly orthogonal signals. Formulas [15b], [16b], [21b], and [22b] can take this difference into account by selecting K3 and K4 values ​​different from 1.00, for example, within the range of 0.80 to 0.98 or within the range of 1.02 to 1.20.

[0138] However, as mentioned above, surprisingly, we found that these signals are very similar to the orthogonal signals, even without the K factor.

[0139] In fact, Figure 7(d) shows the curve obtained by the equation atan2(gr2,gr1). As can be seen, this curve is almost linear and has a slope equal to approximately 2.5. Such high linearity was completely unexpected.

[0140] Figure 7(e) shows the difference (or error) between the mechanical angle α and the value calculated as (0.4)*atan2(gr2,gr1) by applying equation [15a] with K1=0.4. The error is less than ±4° for mechanical angles α varying from approximately 60° to approximately 120°. Such a small error for such a simple equation is unpredictable.

[0141] Figures 7(a) to 7(e) show simulations for angle α only, but these simulations also represent the second angle β. However, in this case, the curve labels are changed from "Bx" to "By" in Figure 7(b), and from "dBz / dx" to "dBz / dy" and from "dBx / dx" to "dBy / dy" in Figure 7(c).

[0142] As described above, the inventors also found that this error can be further reduced to values ​​of less than ±5°, or less than ±3°, or less than ±1.0°, or less than ±0.5°, or even less than ±0.2°, or less than ±0.1°, by known “post-processing techniques,” based on remapping the curve in Figure 7(d) using piecewise linear approximation, for example, where the parameters may be determined during the calibration step and stored in the non-volatile memory of the sensor device.

[0143] From Figure 7(c), it can be seen that the dBz / dx signal alone can be used as a guideline for the first angle, and similarly, the dBz / dy signal alone can be used as a guideline for the second angle. Depending on the application (game console, excavator, etc.), the guideline may or may not be sufficient. The guideline may be further improved by using a lookup table or piecewise linear correction.

[0144] Figure 8(a) shows an exemplary sensor system 800, which includes a cylindrical magnet having a diameter D=8 mm and a height H=4 mm, mounted at a distance g=3 mm from a reference point "Pref" located between two sensors spaced approximately 1.7 mm apart, each comprising an IMC and two horizontal Hall elements (as illustrated in Figure 3 or Figure 5, e.g., each having a diameter of approximately 190 μm.

[0145] Figures 8(b) to 8(e) show the simulation results of this sensor system.

[0146] The curves in Figures 8(b) to 8(e) are very similar to those in Figures 7(b) to 7(e), but the intrinsic linearity of the curve shown in Figure 8(d) is improved, and the intrinsic error shown in Figure 8(e) is reduced to a value within ±3° ("intrinsic linearity" means the linearity of the curve without "post-processing"). As mentioned above, the intrinsic linearity may be improved at K3, K4 different from 1.00 using any of equations [15b], [16b], [21b], and [22b].

[0147] However, naturally, the present invention is not limited to sensor systems having the specific dimensions shown in the examples of Figures 7(a) and 8(a), but also works for systems having, for example, the following combinations of parameters.

[0148] [Table 1]

[0149] Those skilled in the art who benefit from this disclosure can easily find the optimal values ​​for K1, K2, and optionally K3, K4, for example, by performing simulations and / or calibration tests. The values ​​of K1 to K4 can be stored in the non-volatile memory 931 of the sensor device (see, for example, Figure 9).

[0150] Figure 9 shows an electrical block diagram of a circuit 910 that may be used in the position sensor device described above. The circuit 910 comprises a plurality of magnetic sensor elements M1 to M8 (e.g., horizontal Hall elements, vertical Hall elements, MR elements, etc.), a processing unit 930 (e.g., including analog and / or digital components), and a non-volatile memory 931 (e.g., EEPROM or flash). The biasing and reading of circuits including Hall sensors or MR elements are well known in the art and therefore do not need to be described in further detail here.

[0151] This block diagram can be used, for example, in a sensor device having the sensor structure shown in Figure 5 or Figure 6, or in a modified version thereof.

[0152] The sensor device may be configured to measure magnetic field components Bx1 and Bz1 at a first sensor location, Bx2 and Bz2 at a second sensor location, By1 and Bz3 at a third sensor location, and By2 and Bz4 at a fourth sensor location, wherein the first and second sensor locations are located on the X-axis, and the third and fourth sensor locations are located on the Y-axis perpendicular to the X-axis, and the sensor device is configured to determine in-plane gradient dBx / dx and out-of-plane gradient dBz / dx along the X-direction, in-plane gradient dBBy / dy and out-of-plane gradient dBz / dy along the Y-direction, and two angular values ​​α and β based on these magnetic field gradients.

[0153] The first angle α and the second angle β may be determined in the manner described above, for example, by using the formulas [15a] and [15b] or [21a] and [21b] described above, and / or optionally by using a lookup table with interpolation. Optionally, a post-correction step may also be applied, for example, by using piecewise linear correction for α and piecewise linear correction for β. The piecewise linear correction for α may be independent of the piecewise linear correction for β.

[0154] The subtraction of signals to determine the magnetic field component (e.g., h2-h1 in Figure 5) and / or the magnetic field gradient (e.g., Bx2-Bx1 in Figure 5, or v4-v3 in Figure 6) may be performed in the analog domain before or after amplification, or in the digital domain.

[0155] The processing unit 930 may optionally include a non-volatile memory 931 (e.g., NVRAM, EEPROM, or flash memory) or a digital processor which may be connected thereto. This memory may be configured to store one or more constants, for example, K1, K2, and also K3, K4 if used, and optionally, the value or coefficient of the corrected step if applicable. The digital processor 930 may be, for example, an 8-bit processor or a 16-bit processor.

[0156] Although not explicitly shown, the sensor device 910 may further comprise one or more components or subcircuits selected from the group consisting of amplifiers, differential amplifiers, analog-to-digital converters (ADCs), multiplexers, and the like. The ADC may have a resolution of at least 8 bits, or at least 10 bits, or at least 12 bits, or at least 14 bits, or at least 16 bits.

[0157] A major advantage is that the processing circuit does not need to perform a Fast Fourier Transform (FFT), nor does it need to implement a neural network with hundreds of nodes.

[0158] Figure 10 shows a flowchart of method 1000 for determining the orientation (α,β) of a cylindrical magnet having axis (A) with respect to a reference point "Pref" located on a semiconductor substrate, the method being based on at least two of the above magnetic field gradients, a) Determining the first magnetic field gradient dBx / dx of a first magnetic field component Bx oriented in a first direction X parallel to the semiconductor substrate along the first direction X 1001, b) Determining the second magnetic field gradient dBy / dy of the second magnetic field component By which is parallel to the semiconductor substrate along the second direction Y and oriented in the second direction Y perpendicular to the first direction X, 1002 c) Determining the third magnetic field gradient dBz / dx of a third magnetic field component Bz oriented in a third direction Z perpendicular to the semiconductor substrate along the first direction X, 1003, d) Determining the fourth magnetic field gradient dBz / dy of the third magnetic field component Bz oriented in the third direction Z along the second direction Y, 1004, e) Based on at least two of the above magnetic field gradients, determine a first angle α formed between the orthographic projection of the magnet axis "A" on a first virtual plane XZ parallel to the first direction X and the third direction Z 1005, f) Based on at least two of the above magnetic field gradients, determine a second angle β formed between the orthographic projection of the axis "A" of the magnet on a second virtual plane YZ parallel to the second direction Y and the third direction Z 1006, Includes.

[0159] Step e) may include determining the first angle α based only on the first magnetic field gradient dBx / dx and the third magnetic field gradient dBz / dx.

[0160] Step f) may include determining the second angle β based solely on the second magnetic field gradient dBBy / dy and the fourth magnetic field gradient dBz / dy.

[0161] Step e) may include determining a first angle α according to equation [15a] or [15b].

[0162] Step f) may include determining a second angle β according to equation [21a] or [21b].

[0163] To improve accuracy, this method may further include a correction step to reduce or substantially eliminate the nonlinear errors shown in Figures 7(e) and 8(e).

[0164] In variations of this method, steps a) and b) (not explicitly shown) are omitted, step e) includes determining a first angle based on only one magnetic field gradient, i.e., dBz / dx, and step f) includes determining a second angle based on only one magnetic field gradient, i.e., dBz / dy.

[0165] The above describes a system in which the magnet is a cylindrical magnet that can pivot around a reference point "Pref" located on a semiconductor surface. However, the present invention is not limited to this, and also functions when the magnet is a bipolar magnet of a different shape (e.g., spherical or rod-shaped), and / or when the reference point "Pref" is fixed to a semiconductor substrate but located at a non-zero distance "dref" from the semiconductor substrate.

[0166] Figure 11 shows a modified version of the sensor system in Figure 1, in which the magnet 1101 is pivotable around a reference point "Pref" located at a predetermined non-zero distance "dref" on a semiconductor substrate (also defined by the XY plane, though not explicitly shown). In this example, the reference point "Pref" is located on the positive Z axis, meaning that the magnet and the reference point are located on the same side of the substrate. However, the present invention is not limited thereto, and the reference point may be located on the negative Z axis, i.e., on the substrate opposite to the magnet.

[0167] The reference point "Pref" of the system shown in Figures 1 and 11 is located outside the space defined by the size of the cylindrical magnet, and is situated between the semiconductor substrate and the magnet when the magnet is in the neutral position (i.e., α=0°, β=0°).

[0168] However, the present invention is not limited thereto, and also functions when the (real or imaginary) reference point "Pref" on which the axis of the magnet can pivot is located within or above the space defined by the magnet.

[0169] In these cases, it has been found that the same formulas as above may be used to calculate α and β. Alternatively, the first angle α and the second angle β can be calculated as the "atan2" function (the inverse tangent function of the two arguments), where each of the first and second arguments is a linear combination of two or more magnetic field gradients selected from the group consisting of dBx / dx, dBz / dx, dBy / dy, and dBz / dy.

[0170] Optionally, the sensor device may be further adapted to apply post-processing to these angles in a manner known in the art, for example, by applying a first piecewise linear correction to angle α using a first set of predefined coefficients, and by applying a second piecewise linear correction to angle β using a second set of predefined coefficients. These coefficients may be determined during the calibration step and stored in the non-volatile memory of the sensor device.

Claims

1. A sensor device for determining the orientation (α, β, φ, ψ) of a magnet having an axis (A), a semiconductor substrate, i) a first magnetic field gradient (dBx / dx) of a first magnetic field component (Bx) oriented in the first direction (X) along a first direction (X) parallel to the semiconductor substrate, ii) a second magnetic field gradient (dBy / dy) of a second magnetic field component (By) oriented in the second direction (Y) along a second direction (Y) parallel to the semiconductor substrate and perpendicular to the first direction (X), iii) a third magnetic field gradient (dBz / dx) of a third magnetic field component (Bz) oriented in a third direction (Z) perpendicular to the semiconductor substrate along the first direction (X), and iv) a semiconductor substrate including a plurality of magnetic sensors configured to determine a fourth magnetic field gradient (dBz / dy) of the third magnetic field component (Bz) oriented in the third direction (Z) along the second direction (Y), a processing circuit (930) configured to determine a first angle (α, ψ) based on the first magnetic field gradient (dBx / dx) and the third magnetic field gradient (dBz / dx), wherein the first angle (α, ψ) is a first orthogonal projection of the axis (A) of the magnet on a first virtual plane (XZ) parallel to the first direction (X) and the third direction (Z), and the processing circuit (930) formed between the first direction (X) or the third direction (Z), the processing circuit (930) is for determining a second angle (β, φ) based on the second magnetic field gradient (dBy / dy) and the fourth magnetic field gradient (dBz / dy), wherein the second angle (β, φ) is a second orthogonal projection of the axis (A) of the magnet on a second virtual plane (YZ) parallel to the second direction (Y) and the third direction (Z), and the second direction (Y) or the third direction (Z), a sensor device formed therebetween.

2. The plurality of magnetic sensors includes a first sensor (S1), a second sensor (S2), a third sensor (S3), and a fourth sensor (S4), the first sensor (S1) located at a first sensor location and the second sensor (S2) located at a second sensor location are located on a first virtual line oriented in the first direction (X) and are spaced apart from each other by a first distance, The first sensor (S1) is configured to measure a first magnetic field component (Bx1) oriented in the first direction (X) and a second magnetic field component (Bz1) oriented in the third direction (Z), The second sensor (S2) is configured to measure a third magnetic field component (Bx2) oriented in the first direction (X) and a fourth magnetic field component (Bz2) oriented in the third direction (Z), The third sensor (S3) located at the third sensor location and the fourth sensor (S4) located at the fourth sensor location are located on a second virtual line oriented in the second direction (Y), and are separated from each other by a second distance, The third sensor (S3) is configured to measure a fifth magnetic field component (By1) oriented in the second direction (Y) and a sixth magnetic field component (Bz3) oriented in the third direction (Z), The sensor device according to claim 1, wherein the fourth sensor (S4) is configured to measure a seventh magnetic field component (By2) oriented in the second direction (Y) and an eighth magnetic field component (Bz4) oriented in the third direction (Z).

3. The first angle (α) is determined according to the formula α = K1 * atan2(dBz / dx, dBx / dx) wherein, α is the first angle, atan2() is the arctangent function of two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, and K1 is a first predetermined constant, The second angle (β) is determined according to the formula: β = K2 * atan2(dBz / dy, dBy / dy) wherein, β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 is a second predetermined constant, the sensor device according to claim 1 or 2.

4. The first angle (α) is determined according to the formula: α = K1 * atan2(K3 * dBz / dx, dBx / dx) wherein, α is the first angle, atan2() is the arctangent function of two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, and K1 and K3 are predetermined constants, The second angle (β) is determined according to the formula: β = K2 * atan2(K4 * dBz / dy, dBy / dy) wherein, β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 and K4 are predetermined constants, wherein, α is the first angle, atan2() is the arctangent function of two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, and K1 and K3 are predetermined constants, The second angle (β) is determined according to the formula: β = K2 * atan2(K4 * dBz / dy, dBy / dy) wherein, β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 and K4 are predetermined constants, In the formula, β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 and K4 are predetermined constants. The sensor device according to claim 1 or 2.

5. The sensor device according to claim 1, wherein the magnet is movable such that the axis (A) of the magnet is pivotable about a reference point having a predetermined position with respect to the semiconductor substrate.

6. The first distance (ΔX) between the first sensor location and the second sensor location is substantially equal to the second distance (ΔY) between the third sensor location and the fourth sensor location, or The first distance (ΔX) between the first sensor location and the second sensor location is at least 5% greater than or at least 5% less than the second distance (ΔY) between the third sensor location and the fourth sensor location. The sensor device according to claim 2.

7. The sensor device according to claim 2, wherein each of the four sensors (S1 to S4) includes integrated magnetic concentrators (IMC1 to IMC4) and two horizontal Hall elements (H1 to H8).

8. Each of the four sensors (S1 to S4) includes a horizontal Hall element and a vertical Hall element, or The sensor device according to claim 2, wherein each of the four sensors (S1 to S4) includes a horizontal Hall element and at least one magnetoresistive sensor element.

9. The sensor device according to claim 1, wherein the processing circuit is integrated with the semiconductor substrate.

10. A position sensor system (100; 700; 800; 1100) comprising A sensor device according to claim 1 or 2, comprising a semiconductor substrate, and a sensor device; A position sensor system comprising a magnet pivotable about a reference point having a predetermined position with respect to the semiconductor substrate.

11. The position sensor system according to claim 10, wherein the system further comprises a joystick connected to the magnet.

12. A method (1000) for determining the orientation (α, β, φ, ψ) of a magnet pivotable about a reference point having a predetermined position with respect to a semiconductor substrate, wherein The method (1000) comprises a) determining a first magnetic field gradient (dBx / dx) of a first magnetic field component (Bx) oriented in the first direction (X) along a first direction (X) parallel to the semiconductor substrate (1001); b) determining a second magnetic field gradient (dBy / dy) of a second magnetic field component (By) oriented in the second direction (Y) along a second direction (Y) parallel to the semiconductor substrate and perpendicular to the first direction (X) (1002); c) determining a third magnetic field gradient (dBz / dx) of a third magnetic field component (Bz) oriented in a third direction (Z) perpendicular to the semiconductor substrate along the first direction (X) (1003); d) determining a fourth magnetic field gradient (dBz / dy) of the third magnetic field component (Bz) oriented in the third direction (Z) along the second direction (Y) (1004); e) determining a first angle (α, ψ) based on at least the first magnetic field gradient (dBx / dx) and the third magnetic field gradient (dBz / dx) (1005), wherein the first angle (α, ψ) is formed between a first orthogonal projection of an axis (A) of the magnet on a first virtual plane (XZ) parallel to the first direction (X) and the third direction (Z), and the first direction (X) or the third direction (Z); f) determining a second angle (β, φ) based on at least the second magnetic field gradient (dBy / dy) and the fourth magnetic field gradient (dBz / dy) (1006), wherein the second angle (β, φ) is formed between a second orthogonal projection of the axis (A) of the magnet on a second virtual plane (YZ) parallel to the second direction (Y) and the third direction (Z), and the second direction (Y) or the third direction (Z), the method (1000).

13. wherein the first angle (α) is determined according to the formula: α = K1 * atan2(dBz / dx, dBx / dx) wherein α is the first angle, atan2() is the arctangent function of two arguments, dBx / dx is the first magnetic field gradient, dBz / dx is the third magnetic field gradient, and K1 is a first predetermined constant; wherein the second angle (β) is determined according to the formula: β = K2 * atan2(dBz / dy, dBy / dy) wherein β is the second angle, atan2() is the arctangent function of two arguments, dBy / dy is the second magnetic field gradient, dBz / dy is the fourth magnetic field gradient, and K2 is a second predetermined constant; and is determined according to the following: where β is the second angle, atan2() is the arc tangent function of two arguments, dB y / dy is the second magnetic field gradient, dB z / dy is the fourth magnetic field gradient, and K2 is a second predetermined constant, the method (1000) according to claim 12. **Claim 14** The first angle (α) is given by the formula: α = K1 * atan2(K3 * dB z / dx, dB x / dx) where α is the first angle, atan2() is the arc tangent function of two arguments, dB x / dx is the first magnetic field gradient, dB z / dx is the third magnetic field gradient, and K1 and K3 are predetermined constants, The second angle (β) is given by the formula: β = K2 * atan2(K4 * dB z / dy, dB y / dy) where β is the second angle, atan2() is the arc tangent function of two arguments, dB y / dy is the second magnetic field gradient, dB z / dy is the fourth magnetic field gradient, and K2 and K4 are predetermined constants, the method (1000) according to claim 12. ​ ​

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