Magnetoelastic torque sensor devices, systems, and methods

Abstract

A magnetoelastic torque sensor system, the magnetoelastic torque sensor system comprising a shaft having at least one axial portion magnetized in a circumferential direction; and a magnetic sensor device disposed in the vicinity of the shaft; the sensor device comprises a first semiconductor substrate (109) with processing circuitry, a second semiconductor substrate (106a) with a first magnetic sensor (S1), and a third semiconductor substrate (106b) with a second magnetic sensor (S2), each magnetic sensor being configured for measuring a magnetic field component; wherein the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are incorporated into a single package device; and wherein the processing circuitry is configured for determining a pairwise difference between the magnetic field components and for outputting a signal or value indicative of a torque applied on the shaft based on the pairwise difference. A method of measuring a torque applied on a shaft.

Description

Technical Field

[0001] The present invention relates generally to the field of magnetic sensor devices, systems and methods, and more particularly to magnetoelastic torque sensors. Background Art

[0002] Magnetoelastic torque sensors are known in the art. They are based on the reversal of the physical effect of magnetostriction (deformation of a magnetic material by means of an applied magnetic field), where a torque affecting a magnetized shaft causes a twisting of the shaft and, as a result, a modification of the magnetic field outside the shaft. This modification is very sensitive to the degree of torque and can be measured using a magnetic field sensor.

[0003] Magnetoelastic torque sensors have been known in the art for more than 20 years, for example from US Pat. No. 6,047,605 A.

[0004] There is always room for improvement or substitution. Summary of the invention

[0005] An object of an embodiment of the present invention is to provide a magnetoelastic torque sensor system comprising a shaft and at least one magnetic sensor device.

[0006] It is an object of embodiments of the present invention to provide a method of measuring torque applied to a shaft.

[0007] It is an object of embodiments of the present invention to provide such a system or method: the system or method uses a shaft that has only one axial zone magnetized in a circumferential direction, or has two axial zones magnetized in a single circumferential direction (e.g., both clockwise), or has two axial zones magnetized in opposite circumferential directions (e.g., one clockwise and one counterclockwise), or has three axial zones magnetized in different circumferential directions.

[0008] It is an object of embodiments of the present invention to provide a system or method that uses a shaft having two axial regions separated by a distance greater than 3.0 mm or greater than 5.0 mm.

[0009] It is an object of embodiments of the present invention to provide a system or method that uses a shaft having three axial zones.

[0010] It is an object of embodiments of the present invention to provide such a system: the system has improved accuracy (for example, has a better signal-to-noise ratio and / or has a reduced sensitivity to external interference fields), and / or has reduced complexity, and / or is more compact than systems known in the art.

[0011] It is also an object of embodiments of the present invention to provide such a system in which the sensor device can be more easily customized to a specific axis without requiring a complete redesign.

[0012] It is also an object of embodiments of the present invention to provide such systems wherein the sensor device is differently arranged relative to the axis, thereby producing a different form factor and / or allowing a different mounting of the sensor device to, for example, a chassis.

[0013] It is also an object of an embodiment of the present invention to provide a torque sensor system comprising a shaft and a sensor device, the torque sensor system having dimensions that can be more easily changed or customized for a specific application (e.g., for electric bicycles of various sizes) without requiring a complete redesign.

[0014] An embodiment of the present invention also aims to provide a torque sensor system, comprising a shaft and at least one sensor device, which is less sensitive to a displacement of the mounting position of the at least one sensor device (e.g., a displacement in the axial direction of the shaft and / or a displacement in the radial direction of the shaft, or both). In other words, a torque sensor system in which the mounting requirements of the at least one sensor device are relaxed.

[0015] The torque sensor system provided by the present invention can be used in electric bicycles, automotive applications, industrial applications and robotic applications.

[0016] These and other objectives are achieved by embodiments of the present invention.

[0017] According to a first aspect, the present invention provides a magnetoelastic torque sensor system comprising: a shaft comprising at least one (e.g., first) axial portion magnetized in a (e.g., first) circumferential direction; a magnetic sensor device arranged in the vicinity of the shaft and comprising three semiconductor substrates, the three semiconductor substrates comprising at least a first semiconductor substrate containing a processing circuit, a second semiconductor substrate containing a first magnetic sensor, and a third semiconductor substrate containing a second magnetic sensor, each magnetic sensor being configured to measure a magnetic field component of a magnetic field generated by the shaft when a torque is applied to the shaft; wherein the first magnetic sensor and the second magnetic sensor are spaced a predefined distance from each other; wherein the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are incorporated into a single packaged device having a plurality of terminals electrically connected to the first substrate; and wherein the processing circuit is configured to determine a pairwise difference (e.g., ΔBx) between the measured field components and to output a signal or value indicating the torque applied to the shaft based on the pairwise difference.

[0018] Such magnetoelastic torque sensors are based on the reversal of the magnetostrictive physical effect (deformation of a magnetic material by means of an applied magnetic field), where a torque affecting a magnetized shaft causes a twisting of the shaft and, as a result, a modification of the magnetic field outside the shaft. This modification is very sensitive to the degree of torque and can be measured using a magnetic sensor.

[0019] The first substrate is also referred to herein as a "master substrate."

[0020] The second substrate is also referred to herein as the "first sensor substrate".

[0021] The third substrate is also referred to herein as the "second sensor substrate".

[0022] The output signal may be a torque value (eg, expressed in Nm), or may be a digital value proportional to the torque, or may be an analog signal (eg, a voltage signal or a current signal) proportional to the torque.

[0023] The first substrate may be arranged between the second substrate and the third substrate. Alternatively, the second substrate and the third substrate may be mounted on top of or below the first substrate.

[0024] The first sensor and the second sensor may include, for example, one or more horizontal Hall elements (for measuring Bz); or an IMC disk having two horizontal Hall elements (for example, for measuring Bx or By); or one or more vertical Hall elements (oriented in the same direction, for example, for measuring Bx or By); or one or more magnetoresistive (MR) elements (for example, AMR, XMR), (for example, for measuring Bx or By), one or more GMI elements, etc.

[0025] The predefined direction may be X (parallel to the substrate and defined by the position of the sensor element), or Y (parallel to the substrate, but orthogonal to X), or Z (perpendicular to the substrate).

[0026] In an embodiment, the output signal is proportional to the difference, for example using a constant K stored in a non-volatile memory of the sensor device.

[0027] An advantage lies in using the difference signal between two parallel field components, since the resulting output signal has a reduced sensitivity to external interfering fields.

[0028] The first magnetic sensor and the second magnetic sensor are spaced apart from each other by a predefined distance (eg, dx).The predefined distance may be related to one or more dimensions of at least one axial region of the shaft.

[0029] In an embodiment, the first substrate has a size of at most 2.0 mm×2.0 mm or at most 1.5 mm×1.5 mm, and each of the sensor substrates has a size of at most 0.8 mm×0.8 mm or at most 0.5 mm×0.5 mm or at most 0.4 mm×0.4 mm or at most 0.3 mm×0.3 mm, or at most 0.25 mm×0.25 mm. A major advantage is that the contact areas of the sensor substrate will be connected to the contact areas of the main substrate by means of one or more RDL layers, since such contact areas may be smaller than the contact areas to be connected by means of bonding wires or wire bonds. Therefore, the size of the sensor substrate may also be reduced compared to a sensor substrate having the same magnetic sensor but without contact areas to be connected using bonding wires or wire bonds.

[0030] In an embodiment (of a wafer level package device, or a device comprising a lead frame), the first substrate is spaced apart from each of the sensor substrates by at least 1.0 mm, or at least 1.5 mm, or at least 2.0 mm, or at least 2.5 mm.

[0031] In this embodiment, the sensor substrates are intentionally positioned at a relatively large distance from the first (or main) substrate, even though their size and technology allow them to be arranged closer. This is counterintuitive because typically packages are made "as small as possible", but this is not the case here.

[0032] Preferably, the magnetic sensor device has a plurality of external terminals (also referred to herein as "external contacts"), which are electrically connected to the first substrate. The plurality of terminals may include at least three terminals, including: one terminal (e.g., in the form of a contact pad) for receiving a supply voltage (e.g., VDD), one terminal for receiving a reference voltage (e.g., GND), and one output terminal for providing an output signal. These terminals are exposed to the outside world. But of course, the present invention is not limited to magnetic sensor devices having only three terminals, and sensor devices having more than three terminals (e.g., having at least four terminals, or at least six terminals, or at least eight terminals) may also be used.

[0033] In an embodiment, the processing circuit may include a programmable processor having a random access memory (e.g., RAM) and a non-volatile memory (e.g., flash memory). The flash memory may contain at least one constant value, e.g., a scaling factor K, for multiplying at least one difference signal to obtain a torque value (e.g., expressed in Nm). However, the invention is not limited thereto, and an analog signal (e.g., a voltage signal) may also be provided as an indication of the torque value. The difference may be determined in the analog domain.

[0034] In a simple embodiment, the sensor device has two "1D magnetic sensors" that are configured to measure a magnetic field component oriented in a certain direction (e.g., Bz1, Bz2) at two sensor positions separated by a predefined distance (e.g., dx), and a processing circuit configured to determine the difference between the two measured values, and to multiply the difference by a predefined constant stored in a non-volatile memory embedded in the main substrate, and to output the result as a torque value (e.g., expressed in Nm).

[0035] The sensor substrate may include a Hall element and four contact areas, two of which may be used to provide a voltage or current to the Hall element, and another two of which may be used for readout.

[0036] In an embodiment, the magnetic sensor device is configured for measuring or estimating a first temperature of the first sensor and a second temperature of the second sensor and for temperature compensating signals obtained from the first sensor and the second sensor before calculating the difference.

[0037] In an embodiment, the first substrate further comprises a temperature sensor for measuring the temperature of the host substrate, and wherein the processing circuit is configured for temperature correction of the sensor signal based on the measured temperature before determining said difference.

[0038] Temperature correction can be performed in the analog domain or in the digital domain.

[0039] In embodiments where the sensor includes a single horizontal Hall plate, or multiple horizontal Hall plates connected in series or in parallel, the resistance of the Hall plates can be used to estimate the temperature of each Hall plate. The resistance can be determined during a calibration test and can be stored in a non-volatile memory, or can be calculated during actual use (e.g., by applying a known bias voltage and measuring the current flowing through (one or more) Hall plates, or by applying a known bias current and measuring the voltage on (one or more) Hall plates). As an example, typically one or more pairs of Hall plates are used to perform pair-by-pair differential measurements. The average temperature reading can then be used for temperature compensation of the differential measurement. The average temperature can be obtained from the temperature sensor when the position of the temperature sensor on the CMOS substrate is near the center of a virtual circle that intersects the various Hall plates.

[0040] In an embodiment, each of the sensor substrates further comprises a temperature sensor for measuring the temperature of said sensor substrate, and the processing circuit is configured for temperature correcting the sensor signals based on these temperature signals before determining said difference.

[0041] In some embodiments, the magnetically sensitive element itself (eg, a horizontal Hall plate) can be used as a temperature sensor. In this case, no additional contacts and no additional interconnections are required between the sensor substrate and the first substrate.

[0042] In other embodiments, a separate temperature sensor circuit is provided on the sensor substrate, for example including components with a negative temperature coefficient (NTC). In this case, additional contacts and additional interconnections may be required between the sensor substrate and the first substrate.

[0043] In another or further embodiment, the processing circuit is further configured to estimate a first amount of power consumed by the first sensor substrate and a second amount of power consumed by the second sensor substrate, and to estimate a first temperature of the first sensor substrate based on the first amount of power, and to estimate a second temperature of the second sensor substrate based on the second amount of power, and to perform temperature correction on the sensor signal based on the corresponding temperature signal before determining the difference.

[0044] In an embodiment, the first semiconductor substrate comprises a plurality of first contact areas (e.g., first pads), and the second semiconductor substrate comprises a plurality of second contact areas, and the third semiconductor substrate comprises a plurality of first contact areas; and a first subset of the first contact areas is electrically connected (e.g., by means of bonding wires or conductive tracks) to at least some of the second contact areas; and a second subset of the first contact areas is electrically connected to at least some of the third contact areas; and the first semiconductor substrate further comprises a first temperature sensor (T1), which is arranged in a vicinity of at least one contact area from the first subset, and the first temperature sensor (T1) is configured to For providing a first temperature signal indicating the temperature of a second substrate (i.e., the first sensor substrate); and the first semiconductor substrate further includes a second temperature sensor (T2), which is arranged in a vicinity of at least one contact area from the second subset, and the second temperature sensor (T2) is configured to provide a second temperature signal indicating the temperature of a third substrate (i.e., the second sensor substrate); and the processing circuit is further configured to use the first measured temperature to temperature compensate the signal obtained from the first sensor (e.g., S1), and to use the second measured temperature to temperature compensate the signal from the second sensor (e.g., S2).

[0045] Since the first magnetic sensor and the second magnetic sensor are not monolithically integrated, their temperatures may differ greatly from each other, especially if they are spaced relatively far from each other. An advantage is that the temperatures of the first semiconductor substrate and the second semiconductor substrate are estimated by measuring the first temperature and the second temperature on the main substrate at or near the contact area electrically connected to the first sensor or the second sensor, because in practice the electrical connection is also the thermal connection (e.g. a bonding wire made of gold or a copper wire within a redistribution layer). An advantage is that the thermal sensor is provided on the first substrate, because in this way the surface area (and thus the cost) of the second substrate and the third substrate can be reduced, and the number of interconnections between the sensor substrate and the main substrate can also be reduced.

[0046] In an embodiment, the shaft comprises steel or a steel alloy and one or both axial portions of the shaft are magnetized in the circumferential direction.

[0047] In another or further embodiment, at least one axial portion of the shaft comprises or consists of: a magnetized ring mounted or wrapped around the shaft. The ring is attached to the shaft so that application of torque to the shaft is transmitted to the ring. The ring may be made of the same material as the shaft, or may be made of a different material. An advantage of this embodiment is that the ring may be selected from a different material than the rest of the shaft, and the magnetic field generated by the ring may be much larger. The outer diameter of the ring may be the same as the outer diameter of the shaft, or may be larger than the outer diameter of the shaft.

[0048] The first semiconductor substrate may be a CMOS substrate.

[0049] In an embodiment, the first semiconductor substrate comprises primarily silicon; and the second semiconductor substrate and the third semiconductor substrate comprise primarily silicon.

[0050] In an embodiment, the first semiconductor substrate comprises primarily silicon; and the second semiconductor substrate and the third semiconductor substrate are discrete (eg, separate) silicon substrates.

[0051] This solution can be more cost-effective than integrating the Hall sensors in a CMOS chip, since the price per unit area of ​​the fan-out reassembled wafer is much lower than the price per unit area of ​​the wafer processing of the signal conditioning CMOS circuits, especially if the distance between the sensors is relatively large (e.g., greater than 2.0 mm).

[0052] A discrete silicon substrate may include a Hall plate made using a specialized fabrication process that is not compatible with standard CMOS processing, but which nevertheless provides better performance (eg, higher sensitivity) than a CMOS Hall plate.

[0053] In an embodiment, the main substrate as well as the sensor substrate are fabricated in CMOS technology, but using different technology nodes.

[0054] In an embodiment, the main substrate is a CMOS silicon substrate and the sensor substrate is a bipolar silicon substrate.

[0055] In an embodiment, the main substrate may use a first type of sensor element (e.g., a horizontal Hall element or a vertical Hall element), while the sensor substrate may use another type of sensor element (e.g., a magnetoresistive element (e.g., an AMR or XMR element), or a GMI sensor).

[0056] In an embodiment, the first semiconductor substrate mainly includes silicon; and the second semiconductor substrate and the third semiconductor substrate include a compound semiconductor material selected from Group III-V (eg, Ga—As or In—As).

[0057] This embodiment provides a combination of the following advantages: (1) a magnetic sensor with high sensitivity (e.g., approximately an order of magnitude greater than a horizontal Hall sensor implemented in standard CMOS), (2) increased distance between sensor elements, thereby increasing the difference signal, and (3) cost-effective packaging.

[0058] In an embodiment, the sensor device is a wafer level package device; and the first semiconductor substrate is positioned between the second semiconductor substrate and the third semiconductor substrate; and the first semiconductor substrate is electrically connected to the second semiconductor substrate and to the third semiconductor substrate by means of at least one redistribution layer (RDL).

[0059] In an embodiment, the main substrate is arranged relative to the sensor substrates such that a distance between the main semiconductor substrate and any of the sensor substrates is smaller than a distance between the two sensor substrates.

[0060] The active surfaces of the first, second and third semiconductor substrates preferably lie in a single virtual plane, or in other words, the active surfaces of the first, second and third semiconductor substrates preferably are substantially coplanar.

[0061] By positioning the substrates adjacent to each other, the projections of the substrates in a direction perpendicular to the substrates do not overlap each other. This simplifies the routing of the interconnects.

[0062] An advantage is to arrange the three substrates adjacent to each other, because by doing so the risk of one substrate exerting mechanical stress on another (as might be the case, for example, when they are mounted on top of each other and one of the substrates expands, for example due to heat dissipation) can be reduced or avoided.

[0063] This embodiment provides a combination of the following advantages: (1) it allows heterogeneous integration; (2) it allows the distance between sensor elements to be increased independently of the size of the main substrate, so the distance between sensor elements can be optimized for a specific axis; (3) it provides cost-effective packaging; (4) it allows the development of "custom devices" for specific applications (for example, as a torque sensor for a specific axis, which has one or more magnetized regions with specific dimensions, without having to redesign, test and produce a CMOS substrate that is only part of the wafer-level package; (5) in the event of a chip shortage of the sensor substrate, other sensor substrates can be used). In other words, this wafer-level packaging provides great flexibility in design and allows the use and reuse of existing substrates for various applications.

[0064] An advantage of using a good thermally conductive material, such as copper or aluminum, is that at least one redistribution layer (RDL) also serves as a heat sink. In this way, the temperature difference between the main substrate and the sensor substrate is limited on the one hand, and on the other hand it is possible that the temperature measured on the main substrate (e.g. near the connection area of ​​the redistribution layer) can be used as an estimate or approximation of the temperature of the corresponding sensor substrate. If only one temperature sensor is provided on the main substrate, this temperature sensor is preferably located in a central position, e.g. in the middle between the two sensor positions or in the vicinity thereof.

[0065] In an embodiment, the wafer level package device additionally comprises at least one passive SMD component such as a resistor or a capacitor or a diode, for example for suppressing noise and / or for stabilizing voltage supply, and / or for reducing the influence of EMI (electromagnetic interference).

[0066] This provides an important advantage in that the sensitive circuitry is better protected even if the sensor device is not mounted on a printed circuit board. It also allows the package to be mounted more compactly in difficult environments such as, for example, near the axle of an electric bicycle.

[0067] The wafer level package device may further include a plurality of terminals (also referred to herein as “external contacts”) electrically connected to the first substrate (eg, electrically connected to contact regions or pads thereof) by means of the redistribution layer(s).

[0068] In other words, electrical connections from the sensor substrate to the main substrate, and electrical connections from the main substrate to external terminals are formed in the RDL layer(s).

[0069] The projection of the external terminals in a direction perpendicular to the active surface of the substrate may be positioned on the main substrate (so-called "fan-in") or may be located outside the periphery of the main substrate ("fan-out").

[0070] Preferably, for reasons of stress due to soldering, the projection of the (external) terminals is not located on the sensor substrate. Some of the terminals may be positioned near the corners of the package. External devices may be connected to these terminals by means of wire bonding or soldering, etc.

[0071] The advantage is that the external terminals are in direct contact with the RDL layer, allowing them to be produced using photolithography processes. This is not the case when using lead frames.

[0072] An advantage is that the active surfaces of the three substrates lie in the same (virtual) plane (i.e., they are coplanar) even though the substrates have different thicknesses. This makes it possible to mount the three substrates at the same distance from an external object (e.g., a shaft, a magnet surface, etc.). This also allows many or all of the vias of the redistribution RDL layer to have substantially the same length (in a direction perpendicular to the substrate).

[0073] In an embodiment, the number of redistribution layers is only one or only two.

[0074] This offers the advantage of a cheaper and thinner package and avoids the need for a complex three-dimensional redistribution layer stack.

[0075] In an embodiment, the magnetic sensor device further includes a lead frame; and the first substrate is positioned on a single side of the lead frame, between the second semiconductor substrate and the third semiconductor substrate; and the first semiconductor substrate is electrically connected to the second semiconductor substrate and to the third semiconductor substrate by means of bonding wires. (For example, directly connected or indirectly connected via the lead frame).

[0076] Figure 7 An example of such a sensor device is shown in FIG.

[0077] The three substrates are arranged next to each other. By doing so, the risk of one substrate exerting mechanical stress on another substrate (which would be the case, for example, when they are mounted on top of each other and one of the substrates expands, for example due to heat dissipation) can be avoided.

[0078] Preferably, the electrical interconnection between the first semiconductor substrate and the sensor substrate is inside the package, i.e., not exposed, and thus not accessible from outside the package. Some contact areas (or pads) of the first semiconductor substrate are electrically connected to external leads (e.g., for receiving a supply voltage signal VDD, a reference voltage signal GND, and for outputting a torque signal, or a signal or value indicating torque).

[0079] In an embodiment, the lead frame additionally comprises at least one passive SMD component such as a resistor or a capacitor or a diode, for example for suppressing noise and / or for stabilizing the voltage supply, and / or for reducing the influence of EMI (Electromagnetic Interference).

[0080] This provides an important advantage in that the sensitive circuitry is better protected even if the sensor device is not mounted on a printed circuit board. It also allows the package to be mounted more compactly in difficult environments such as, for example, near the axle of an electric bicycle.

[0081] In an embodiment, the magnetic sensor device further includes a lead frame; and the first semiconductor substrate is mounted to the lead frame, and the second semiconductor substrate and the third semiconductor substrate are arranged on top of or below the first substrate; and the first semiconductor substrate is electrically connected to the second semiconductor substrate and to the third semiconductor substrate by means of bonding wires. (For example, directly connected or indirectly connected via the lead frame).

[0082] exist FIG. 6A to FIG. 6C An example of such a sensor device is shown in FIG.

[0083] Preferably, the electrical interconnection between the first semiconductor substrate and the sensor substrate is inside the package, i.e., not exposed, and thus not accessible from outside the package. Some contact areas (or pads) of the first semiconductor substrate are electrically connected to external leads (e.g., for receiving a supply voltage signal VDD, a reference voltage signal GND, and for outputting a signal indicating torque, such as a torque signal).

[0084] In an embodiment, the axis includes at least a first axial portion magnetized in a first circumferential direction, and optionally also includes a second axial portion magnetized in a second circumferential direction opposite to the first circumferential direction; and the magnetic sensor device is oriented relative to the axis so that a first axis (e.g., X) defined by a virtual line passing through the first sensor and the second sensor is parallel to the axis; and the first sensor and the second sensor are configured to measure a first magnetic field component and a second magnetic field component oriented parallel to the axis; and the first sensor is positioned at a first axial position near the middle of the first magnetized axial portion, and wherein the second sensor is positioned near the middle of the second magnetized axial portion (if present).

[0085] Fig.10 and Fig.17 An example of this embodiment is shown in FIG.

[0086] The sensor device may be configured for determining the torque based on a difference (eg ΔBx) between the first magnetic field component and the second magnetic field component, eg proportional to the difference.

[0087] The shaft preferably comprises two axial portions magnetized in opposite circumferential directions, but this is not absolutely necessary and one of these axial portions may be omitted.

[0088] In an embodiment, the magnetic sensor device is oriented relative to an axis such that a first axis (e.g., X) defined by a virtual line passing through a first sensor and a second sensor is oriented radially with respect to the axis; and the first sensor and the second sensor are configured to measure a first magnetic field component and a second magnetic field component oriented parallel to the axis; and the first sensor is positioned at an axial position near the middle of the magnetized axial portion, at a first radial distance (e.g., d1) from the axis, and wherein the second sensor is positioned at the same axial position as the first sensor, but at a second radial distance (e.g., d2) from the axis that is greater than the first axial distance.

[0089] Fig.13 and Fig.15 An example of this embodiment is shown in FIG.

[0090] The sensor device may be configured for determining the torque based on a difference between the first magnetic field component and the second magnetic field component (eg ΔBax), eg proportional to the difference.

[0091] Depending on the orientation of the sensor element, the axial component Bax relative to the axis and the component By of the sensor element ( Fig.13 ) or component Bz( Fig.15 ) corresponding to.

[0092] In an embodiment, the magnetic sensor device is oriented relative to the axis so that a first axis (e.g., X) defined by a virtual line passing through the first sensor and the second sensor is parallel to the axis; and the first sensor and the second sensor are configured to measure a first magnetic field component and a second magnetic field component oriented radially with respect to the axis; and the first sensor is positioned at a first axial position near a first edge of the magnetized axial portion, and the second sensor is positioned at a second axial position near a second edge of the magnetized axial portion.

[0093] Fig.11 An example of this embodiment is shown in FIG.

[0094] The sensor device may be configured for determining the torque based on a difference (eg ΔBz) between the first magnetic field component and the second magnetic field component, eg proportional to the difference.

[0095] In an embodiment, the magnetic sensor device is oriented relative to an axis so that a first axis (e.g., X) defined by a virtual line passing through the first sensor and the second sensor is radially oriented with respect to the axis; and the first sensor and the second sensor are configured to measure a first magnetic field component and a second magnetic field component radially oriented with respect to the axis; and the first sensor and the second sensor are positioned at an axial position near a first edge of the magnetized axial portion.

[0096] exist Fig.12 and Fig.14 An example of this embodiment is shown in FIG.

[0097] The sensor device may be configured for determining the torque based on a difference (eg ΔBx) between the first magnetic field component and the second magnetic field component, eg proportional to the difference.

[0098] In an embodiment, the axis includes at least a first axial portion magnetized in a first circumferential direction, and optionally also includes a second axial portion magnetized in a second circumferential direction opposite to the first circumferential direction; and the magnetic sensor device is oriented relative to the axis so that a first axis (e.g., X) defined by a virtual line passing through the first sensor and the second sensor is parallel to the axis; and the first sensor and the second sensor are configured to measure a first magnetic field component and a second magnetic field component radially oriented with respect to the axis; and the first sensor is positioned at a first axial position near an edge of the first magnetized axial portion, and wherein the second sensor is positioned near an edge of the second magnetized axial portion (if present).

[0099] Fig. 9 and Fig.16 An example of this embodiment is shown in FIG.

[0100] Depending on the orientation of the sensor element, the radial component Br relative to the axis and the component Bz of the sensor element ( Fig. 9 ) or ComponentBy( Fig.16 ) corresponding to.

[0101] The shaft preferably comprises two axial portions magnetized in opposite circumferential directions, but this is not absolutely necessary and one of these axial portions may be omitted.

[0102] In an embodiment, the shaft includes a first axial portion magnetized in a first circumferential direction, and a second axial portion also magnetized in the first circumferential direction; and the magnetic sensor device is oriented relative to the shaft so that a first axis (e.g., X) defined by a virtual line passing through the first sensor and the second sensor is parallel to the shaft; and the first sensor and the second sensor are configured to measure a first magnetic field component and a second magnetic field component radially oriented with respect to the axis; and the first sensor and the second sensor are either both positioned near an inner edge of the corresponding axial portion, or both positioned near an outer edge of the corresponding axial portion.

[0103] Fig.18 and Fig.19 An example of this embodiment is shown in FIG.

[0104] Depending on the orientation of the sensor element, the radial component Br relative to the axis and the component Bz of the sensor element ( Fig.18 ) or ComponentBy( Fig.19 ) corresponding to.

[0105] According to a second aspect, the present invention also provides a method for measuring the torque applied to a shaft, comprising the following steps: a) providing a shaft comprising at least one (e.g., first) axial portion magnetized in a (e.g., first) circumferential direction; b) providing a magnetic sensor device in the form of a single packaged device, the magnetic sensor device comprising at least three semiconductor substrates, the at least three semiconductor substrates comprising: a first semiconductor substrate (e.g., CMOS), the first semiconductor substrate comprising at least a processing circuit; a second semiconductor substrate (e.g., Ga-As), the second semiconductor substrate comprising a first magnetic sensor; and a third semiconductor substrate (e.g., Ga-As), the third semiconductor substrate comprising a second magnetic sensor; c) arranging the sensor device near the shaft; d) measuring a first magnetic field component (e.g., Bz1) using the first magnetic sensor; and measuring a second magnetic field component (e.g., Bz2) using the second magnetic sensor; e) determining a pairwise difference (e.g., ΔBz) between the magnetic field components; f) outputting a signal or value indicating the torque applied to the shaft based on the pairwise difference.

[0106] Step a) may comprise providing a shaft having only one axial portion, the axial portion being magnetized in the circumferential direction.

[0107] Step a) may comprise providing a shaft having only two axial portions which are magnetized in opposite circumferential directions and having a non-magnetized portion between the two axial portions.

[0108] Step a) may comprise providing a shaft having three axial sections magnetised in opposite circumferential directions (ie not all magnetised in the same direction) with two non-magnetised sections therebetween.

[0109] Step b) may include providing such a device, wherein the two magnetic sensors are spaced apart by a predefined distance (e.g., dx) along the first direction (X), the predefined distance being in the range from 1.5 mm to 25.0 mm, or from 2.5 mm to 25.0 mm, or from 4.0 mm to 25.0 mm, or from 6.0 mm to 25 mm, or from 8.0 mm to 25 mm, or from 10 mm to 25 mm, or from 12 mm to 25 mm.

[0110] Step b) may comprise providing such a device, wherein each of the two magnetic sensors is a 1D magnetic pixel, for example comprising only horizontal Hall elements.

[0111] Step c) may comprise arranging the sensor components such that the first sensor (eg S1 ) is positioned at an axial position near the centre of the first magnetised region.

[0112] Step c) may comprise arranging the sensor device such that the first sensor (eg S1 ) is positioned at an axial position near an edge of the first magnetised region (eg at an axial distance of at most 3.0 mm from said edge).

[0113] Step c) may comprise orienting the sensor device such that an imaginary axis (eg X) between the first sensor and the second sensor is oriented substantially parallel to the longitudinal axis of the shaft.

[0114] Step c) may comprise orienting the sensor device such that an imaginary axis (eg X) between the first sensor and the second sensor is oriented substantially orthogonal to the longitudinal axis of the shaft, eg radially.

[0115] Step f) may include outputting a voltage proportional to the paired difference, or outputting a digital value proportional to the paired difference.

[0116] Step f) may include calculating and outputting a torque value (eg, T) based on the pairwise differences.

[0117] If the shaft has two axial portions which are circumferentially magnetized, and if an imaginary axis (X) between the two sensors is substantially parallel to the longitudinal axis of the shaft, the second sensor may be arranged in the vicinity of the second axial portion.

[0118] In an embodiment, the first substrate further includes a temperature sensor (for example, near a center position of the first substrate), and step d) further includes: measuring the temperature of the first substrate, and using the measured temperature of the first substrate as an estimate of the temperature of the first sensor substrate and the second sensor substrate to temperature compensate the measured values ​​of the first sensor and the second sensor.

[0119] In an embodiment, the first substrate further includes two temperature sensors, for example, a first temperature sensor positioned near a contact area connected to a contact area of ​​the first sensor substrate and a second temperature sensor positioned near a contact area connected to a contact area of ​​the second sensor substrate, and step d) further includes: measuring a first temperature by the first temperature sensor and temperature compensating the measured value of the first sensor using the first temperature; and measuring a second temperature by the second temperature sensor and temperature compensating the measured value of the second sensor using the second temperature.

[0120] According to a third aspect, the present invention also provides a magnetoelastic torque sensor system, comprising: an axis, the axis comprising a first axial portion, a second axial portion and a third axial portion magnetized in a first circumferential direction, a second circumferential direction and a third circumferential direction, respectively, the second axial portion is located between the first axial portion and the third axial portion, the third circumferential direction is equal to the first circumferential direction (for example, clockwise), and the second circumferential direction is opposite to the first circumferential direction (for example, counterclockwise); and at least one magnetic sensor device, the magnetic sensor device is arranged near the axis, and the magnetic sensor device includes three semiconductor substrates, the three semiconductor substrates include to A first semiconductor substrate containing a processing circuit, a second semiconductor substrate containing a first magnetic sensor, and a third semiconductor substrate containing a second magnetic sensor, each magnetic sensor being configured to measure a magnetic field component (e.g., Bz1, Bz2) of a magnetic field generated by the shaft when a torque is applied to the shaft; wherein the first magnetic sensor and the second magnetic sensor are separated from each other by a predefined distance (e.g., dx); wherein the processing circuit is configured to determine a pairwise difference (e.g., ΔBz) between the measured field components, and to output the pairwise difference, and / or to output a signal or value indicating the torque applied to the shaft based on the pairwise difference.

[0121] In a variant, the torque sensor system according to the third aspect further includes a processor (e.g., an electronic control unit) located outside the magnetic sensor device, in which case the main substrate of the sensor device can be omitted; or the main substrate can be present and can be configured to bias and read out the sensor and optionally output the sensor signals after temperature correction, but the pairwise differences can be calculated in the external processor.

[0122] In an embodiment, the first semiconductor substrate is a CMOS substrate; and the second semiconductor substrate and the third semiconductor substrate include a compound semiconductor material selected from Group III-V (eg, Ga—As or In—As).

[0123] In an embodiment, the first sensor and the second sensor are configured for measuring a magnetic field component oriented in a radial direction of the shaft.

[0124] In an embodiment, the first sensor and the second sensor are configured for measuring a magnetic field component oriented in an axial direction of the shaft.

[0125] In an embodiment, the first sensor and the second sensor are configured for measuring two orthogonal magnetic field components, one oriented in a radial direction of the shaft and one oriented in an axial direction of the shaft.

[0126] In an embodiment, the first sensor and the second sensor are located in a first virtual plane (eg, Fig.22A In the space between a first virtual plane (e.g., Ω1) and a second virtual plane (e.g., Ω2), the first virtual plane is oriented perpendicular to the axial direction of the axis (e.g., X) and intersects the axis at a first axial position between the first magnetized portion and the second magnetized portion, and the second virtual plane is oriented perpendicular to the axial direction of the axis and intersects the axis at a second axial position between the second magnetized portion and the third magnetized portion.

[0127] In an embodiment, the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are incorporated into a single module or a single packaged device.

[0128] In an embodiment, the distance dA between the first axial zone and the second axial zone is substantially equal to the distance dB between the second axial zone and the third axial zone (e.g., within a tolerance margin of ±25%); and the radial distance ds between the shaft and the first sensor and the second sensor is substantially equal to the distance dA (e.g., within a tolerance margin of ±25%), and the distance dx between the first sensor and the second sensor is a value in the range from (L2-2×dA) to (L2+dA), where L2 is the axial length of the second magnetized zone. Preferably dx is a value in the range from (L2-2×dA) to (L2), or a value in the range from (L2-1.5×dA) to (L2-0.5×dA), or in the range from (L2-1.25×dA) to (L2-0.75×dA), for example, dx is substantially equal to (L2-dA).

[0129] In an embodiment, the sensor system comprises two magnetic sensor devices mounted near the shaft (e.g. between the first virtual plane and the second virtual plane), and the two magnetic sensor devices are circumferentially spaced apart by an angle (e.g. θ) of at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95°, such as by an angle in the range of 165° to 180°. The signals from the two magnetic sensor devices may be combined by one of the magnetic sensor devices, or by an external processor, to determine a torque value applied to the shaft.

[0130] In an embodiment, the sensor system comprises three magnetic sensor devices mounted near the shaft (e.g. between the first virtual plane and the second virtual plane), and the three magnetic sensor devices are circumferentially spaced apart by an angle (e.g. θ) of at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95°, for example spaced apart by an angle in the range of 105° to 135°. Signals from the three magnetic sensor devices may be combined by one of the magnetic sensor devices, or by an external processor, to determine a torque value applied to the shaft.

[0131] In an embodiment, the sensor system comprises four magnetic sensor devices mounted near the shaft (e.g. between the first virtual plane and the second virtual plane), and the four magnetic sensor devices are circumferentially spaced apart by an angle (e.g. θ) of at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95°, for example spaced apart by an angle in the range of 80° to 100°. The signals from the four magnetic sensor devices may be combined by one of the magnetic sensor devices, or by an external processor, to determine a torque value applied to the shaft.

[0132] According to a fourth aspect, the present invention also provides a shaft for a magnetoelastic torque sensor system (e.g., for electric bicycles, automotive applications, industrial applications, robotic applications), wherein the shaft includes at least one axial portion magnetized in a circumferential direction; and wherein at least one outer portion of the at least one axial portion is made of martensitic aged steel (e.g., including 17wt% to 19wt% nickel), or of (e.g., hardened) martensitic stainless steel (e.g., including 12wt% to 17wt% Cr (chromium)).

[0133] The outer portion may be formed integrally with the inner portion of the shaft (forming a solid shaft) or may be a ring portion fixedly mounted to the inner portion of the shaft or to an inner shaft.

[0134] In an embodiment, the axial length of the at least one axial zone is a value in the range of 5.0 mm to 15.0 mm, for example, equal to about 8.7 mm, or equal to about 13.7 mm; and the outer diameter of the at least one axial zone is a value in the range of 10 mm to 30 mm, or a value in the range of 15 mm to 25 mm, for example, equal to about 17 mm.

[0135] In an embodiment, the shaft comprises at least two axial sections magnetized in opposite circumferential directions, or comprises at least three axial sections magnetized in alternating circumferential directions; and at least outer portions of the at least two axial sections or at least three axial sections are made of maraging steel (preferably comprising 17wt% to 19wt% Ni), or of (e.g. hardened) martensitic stainless steel (preferably comprising 12wt% to 17wt% Cr).

[0136] In an embodiment, the outer part(s) are made of so-called 18Ni maraging steel having a 200 steel grade, or a 250 steel grade, or a 300 steel grade, or a 350 steel grade, referred to as a maraging C200 steel alloy, a maraging C250 steel alloy, a maraging C300 steel alloy, or a maraging C350 steel alloy.

[0137] In an embodiment, the outer portion(s) are made of a maraging T200 steel alloy, a maraging T250 steel alloy, a maraging T300 steel alloy or a maraging T350 steel alloy.

[0138] In an embodiment, the outer part(s) are made of a steel containing 17 to 19 wt % nickel and 8 to 12 wt % cobalt.

[0139] In an embodiment, the outer part(s) are made of a steel containing 17 wt % to 19 wt % nickel and 8 wt % to 12 wt % cobalt, and 3 wt % to 5 wt % molybdenum.

[0140] In an embodiment, the outer part(s) are made of a steel containing 17 to 19 wt % nickel and 8 to 12 wt % cobalt, as well as 3 to 5 wt % molybdenum and 0.2 to 1.6 wt % titanium.

[0141] In an embodiment, the outer part(s) are made of stainless steel containing 17wt% to 19wt% nickel and 8wt% to 12wt% cobalt, and 3wt% to 5wt% molybdenum and 0.2wt% to 1.6wt% titanium and at least 0.1wt% chromium.

[0142] In an embodiment, the outer portion(s) are made of martensitic stainless steel having 410 steel grade, or 420 steel grade, or 440 steel grade, also referred to as Type 410, Type 420 or Type 440, preferably in the H temper (ie hardened).

[0143] In an embodiment, the outer portion(s) are made of martensitic stainless steel of type 416 or type 440B.

[0144] In an embodiment, the martensitic stainless steel includes 12% to 17 wt % Cr.

[0145] In an embodiment, the martensitic stainless steel comprises is hardened.

[0146] In an embodiment, the outer portion(s) are made of steel (eg maraging steel or (eg hardened) martensitic stainless steel) having a coercivity (Hc) of at least 35 Oersted, or at least 40 Oersted, or at least 45 Oersted.

[0147] In an embodiment, the distance between two adjacent axial zones (e.g., dA, dB) is a value in the range of 0.5 mm to 1.5 mm; for example, equal to about 1.0 mm; and the axial lengths of the at least two axial zones or the at least three axial zones (e.g., L1, L2, L3) are values ​​in the range of 5.0 mm to 15.0 mm, for example, equal to about 8.7 mm, or equal to about 13.7 mm; and the outer diameters of the at least two axial zones or the at least three axial zones are values ​​in the range of 10 mm to 30 mm, or in the range of 15 mm to 25 mm, for example, equal to about 17 mm.

[0148] In an embodiment, the shaft is a crank shaft (e.g., for an electric bicycle), and the shaft has a first end, and a second end opposite the first end, and each of the first end and the second end has at least one flat portion, or at least two flat portions (e.g., opposite each other), or at least four flat portions (e.g., having an overall square cross-section, optionally with rounded corners).

[0149] Furthermore, optionally, each of the first end and the second end has a blind hole extending in the axial direction and having an internal thread or an external thread.

[0150] The flat portion may be configured for mounting a first crank at a first end of the shaft and mounting a second crank at a second end of the shaft.

[0151] According to a fifth aspect, the present invention also provides an electric bicycle comprising one or more of the following: i) a magnetoelastic torque sensor system according to the first aspect; ii) a magnetoelastic torque sensor system according to the third aspect; iii) an axle according to the fourth aspect.

[0152] In an embodiment, the electric bicycle further includes a first crank mounted at the first end and a second crank mounted at the second end.

[0153] Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate, and not merely as explicitly set out in the claims. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0154] Figure 1A and Figure 1B Illustrative examples of magnetic sensor devices that may be used with embodiments of the present invention are shown. Figure 1A is a top view, and Figure 1B yes Figure 1A Cross-sectional view of the magnetic sensor device along line AA.

[0155] Figure 2 yes Figure 1A and Figure 1B Functional block diagram of a magnetic sensor device.

[0156] Figure 3 Shows the production Figure 1A and Figure 1B Flowchart of a method for a magnetic sensor device such as the magnetic sensor device shown in .

[0157] Figure 4 (a) to Figure 4 (j) A more detailed diagram showing the possible uses for producing Figure 1A and Figure 1B The various steps of the method of making a magnetic sensor device like the magnetic sensor device shown in .

[0158] Figure 5 Shows Figure 1A An example of a variation of a magnetic sensor device having four terminals, as may be used in embodiments of the present invention.

[0159] FIG. 6A to FIG. 6C Examples of other magnetic sensor devices that can be used in embodiments of the present invention are shown. These sensor devices include: a lead frame, a first (main) semiconductor substrate mounted on the lead frame, and two sensor substrates mounted on top of or below the first semiconductor substrate.

[0160] Figure 7 An example of another magnetic sensor device that can be used in embodiments of the present invention is shown. The sensor device comprises: a lead frame, a first semiconductor substrate mounted on the lead frame, and two sensor substrates also mounted directly on the lead frame in such a way that the first semiconductor substrate is positioned between the two sensor substrates.

[0161] Fig. 8A and Figure 8B It can be used for Figures 9 to 19 Abstract representation of the magnetic sensor device in the torque sensor system described in Figures 5 to 7 Any of the magnetic sensor devices shown in and variations thereof and are used to illustrate relative position and orientation with respect to an axis. Fig. 8A is a cross-sectional side view, and Figure 8B It is a schematic top view.

[0162] Figures 9 to 19 An illustrative example of a magnetoelastic torque sensor system proposed by the present invention is shown, which uses a single packaged sensor device including three semiconductor substrates, for example, as shown in FIG. Figure 7 or variations thereof.

[0163] Fig. 20 An illustrative example of a magnetoelastic torque sensor system proposed by the present invention is shown, comprising a shaft with three magnetized regions, and a magnetic sensor device comprising two sensor substrates and optionally also a processing circuit.

[0164] Fig.21 Shown for a similar Fig. 20 Simulation results of the torque sensor system.

[0165] Fig.22A Shows something like Fig. 20 A side view of a torque sensor system of a torque sensor system, and Fig. 22B Shows something like Fig. 20 A front view of a torque sensor system of FIG. 1 having two magnetic sensor devices angularly spaced 180° apart in a circumferential direction.

[0166] Fig.23 A flow chart showing a method for determining a torque applied to a shaft according to an embodiment of the present invention is shown, for example, Figures 9 to 19 In the arrangement shown in FIG.

[0167] Fig.24A flow chart showing a method for determining the torque applied to a shaft having three magnetized regions according to an embodiment of the present invention is shown, for example, Figures 20 to 22B In the arrangement shown in FIG.

[0168] Fig.25 A graph showing the results of measurements of the magnetic field strength measured at a distance of about 1 mm from a shaft made of maraging steel or made of (eg hardened) martensitic stainless steel, such as Fig.21 It is magnetized as shown in the figure and has an outer diameter of 17 mm.

[0169] Fig.26 A 3D view of an illustrative example of an axle for an electric bicycle is shown.

[0170] These drawings are only schematic and non-limiting. In the drawings, for illustrative purposes, the size of some of the elements may be exaggerated and not drawn to scale. Any reference numerals in the claims should not be construed as limiting the scope. In different drawings, the same reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0171] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims.

[0172] The terms first, second, etc. in the specification and in the claims are used to distinguish between similar elements and not necessarily to describe a sequence in time, space, level, or in any other manner. It should be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in a sequence different from that described or illustrated herein.

[0173] The terms top, bottom, etc. in the specification and claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in orientations other than those described or illustrated herein.

[0174] It should be noted that the term "comprising" used in the claims should not be interpreted as being limited to the means listed thereafter; it does not exclude other elements or steps. Thus, the term should be interpreted as specifying the presence of the stated 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. Thus, the scope of the expression "a device comprising means A and B" should not be limited to a device consisting only of component A and component B. This means that for the present invention, the only relevant components of the device are A and B.

[0175] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, but may refer to different embodiments. Furthermore, in one or more embodiments, as would be apparent to one of ordinary skill in the art from this disclosure, the particular features, structures, or characteristics may be combined in any suitable manner.

[0176] Similarly, it should be appreciated that in the description of exemplary embodiments of the present invention, for the purpose of streamlining the present disclosure and assisting in the understanding of one or more of the various inventive aspects, the various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than the features explicitly recited in each claim. On the contrary, as reflected in the appended claims, the inventive aspects lie in fewer features than all of the features of a single previously disclosed embodiment. Thus, the claims appended to the Detailed Description are hereby expressly incorporated into the Detailed Description, with each claim itself representing a separate embodiment of the present invention.

[0177] In addition, although some embodiments described herein include some features included in other embodiments but do not include other features included in these other embodiments, the combination of features of different embodiments is intended to fall within the scope of the present invention and form different embodiments as will be understood by those skilled in the art. For example, in the appended claims, any of the embodiments claimed for protection may be used in any combination.

[0178] In the description provided herein, numerous specific details are set forth. However, it should be understood that embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, structures, and techniques are not shown in detail to avoid obscuring the understanding of this specification.

[0179] In this document, the abbreviation "RDL" means "Redistribution Layer(s)".

[0180] In this document, the abbreviation "IMC" means "Integrated Magnetic Concentrator".

[0181] In this document, the abbreviation "SNR" means "Signal-to-Noise Ratio".

[0182] In this document, the abbreviation "MR element" means "magnetoresistive element".

[0183] In this document, the term “magnetic sensor device” or “sensor device” refers to a device including three semiconductor substrates that are integrated in a single package and, for example, arranged adjacent to each other or on top of each other.

[0184] In this document, the expressions "axial portion of the shaft" and "axial zone of the shaft" have the same meaning and are interchangeable.

[0185] Embodiments of the present invention may be described using a Cartesian coordinate system fixed to the sensor device and having three axes X, Y, Z, wherein the X-axis and the Y-axis are parallel to the substrate and the Z-axis is perpendicular to the substrate. The X-axis may be defined by the first sensor position and the second sensor position. Embodiments of the present invention may also be described using a polar coordinate system relative to the axis. The coordinate system defines axial, radial and circumferential directions about the axis. The correspondence between the coordinate systems depends on the relative orientation of the sensor device relative to the axis.

[0186] In this document, the expression "substrate mainly comprises silicon" means that at least 50% of the atoms of the substrate are Si (silicon) atoms. Examples of such substrates include: silicon substrate, silicon-on-insulator SoI substrate, bipolar silicon substrate, CMOS substrate.

[0187] In this document, the expression "the sensor is arranged near an edge of a magnetized zone" or "the sensor is arranged near an edge" means that the sensor is closer to the edge than to an imaginary circle halfway between the two edges of the zone, unless the context clearly indicates otherwise.

[0188] The present invention relates to the field of magnetoelastic torque sensors. Such magnetoelastic torque sensors are based on the reversal of the magnetostrictive physical effect (deformation of a magnetic material by means of an applied magnetic field), wherein a torque affecting a magnetized shaft causes a torsion of the shaft and, as a result, a modification of the magnetic field outside the shaft. This modification is very sensitive to the degree of torque and can be measured using a magnetic field sensor device.

[0189] Such magnetoelastic torque sensors may be used, for example, in electric bicycles, automotive applications, industrial applications, robotic applications, etc. A typical requirement is that the torque sensor has good accuracy even in the presence of magnetic interference fields, although the shaft may only generate a relatively weak magnetic field (e.g., with a magnetic field strength of less than 10 mT, or less than 3 mT, or less than 1 mT). Due to the variety of applications in which the torque sensor may be used, various geometric arrangements will be proposed.

[0190] exist Figures 9 to 19 In the following, various torque sensor systems proposed by the present invention will be described. These torque sensor systems include a shaft and a magnetic sensor device including two magnetic sensors.

[0191] A variety of shafts can be used. The shaft has at least one axial region that is magnetized in the circumferential direction. In some embodiments (e.g., Figures 11 to 15 ), the shaft has only one axial region that is magnetized in the circumferential direction. In other embodiments, the shaft has two axial regions that are magnetized in opposite circumferential directions. In still other embodiments (e.g., as Fig.18 and Fig.19 ), the shaft has two axial regions magnetized in the same circumferential direction. In still other embodiments (e.g., as Figures 20 to 22B ), the shaft has three axial zones magnetized in alternating circumferential directions.

[0192] Various magnetic sensor devices may be used.The magnetic sensor device comprises two magnetic sensors S1 , S2 spaced apart over a predefined distance dx.The distance dx may be matched to the size of one or more axial zones of the shaft.

[0193] Magnetoelastic torque sensors, including shafts and sensor devices, have been known for more than 20 years. During these 20 years, the dimensions of the shafts (for a particular application) have hardly changed, but the dimensions of the electronic components (especially those implemented in CMOS technology) have changed dramatically. In particular, over the years it has become possible to integrate magnetic sensors, digital storage and digital processing circuitry on a single semiconductor die, and to reduce the size of such a die to dimensions less than about 2.0 mm×2.0 mm. Although such a high level of integration and miniaturization is highly desirable in certain technical fields, it does not automatically result in a good solution in the field of magnetoelastic torque sensors. In fact, the magnetic field generated by the magnetoelastic effect is relatively weak (for example, the magnetic field strength generated by such a shaft is typically less than 10 mT, or less than 3 mT, or less than 1 mT).

[0194] The challenge is to provide a cost-effective solution (a very important criterion for high volume and highly competitive markets such as the automotive and / or e-bike industries), which is easy to mount with respect to the axis, is highly insensitive to external interfering fields, and offers good accuracy, preferably all of these characteristics.

[0195] The solutions proposed by the present invention are novel because they utilize novel sensor devices, or because they utilize a novel arrangement of the sensor devices relative to the shaft, or both. Alternatively or additionally, the distance dx between the sensor elements can be selected such that the resulting accuracy of the measured torque signal is relatively high (e.g. with a good signal-to-noise ratio SNR), while the mounting requirements (e.g. axial and / or radial) are relatively low.

[0196] Figure 1 to Figure 7 Illustrative examples of sensor devices that may be used in the torque sensor system proposed by the present invention will be described. Fig. 8A and Figure 8B is an abstract representation of such a sensor device, and Figures 9 to 19 A magnetoelastic torque sensor system proposed by the present invention will be described, wherein such a sensor device is arranged in a specific manner with respect to one or both magnetized regions of the shaft.

[0197] The present invention provides a magnetoelastic torque sensor system, which includes a shaft and a magnetic sensor device arranged near the shaft. The shaft includes at least one axial portion magnetized in the circumferential direction. The magnetic sensor device includes three semiconductor substrates, which include a first semiconductor substrate (e.g., a CMOS substrate, referred to as "main" herein) containing at least a processing circuit, a second semiconductor substrate (e.g., a GaAs substrate) containing at least a first magnetic sensor S1, and a third semiconductor substrate (e.g., a GaAs substrate) containing at least a second magnetic sensor S2. Each magnetic sensor is configured to measure a magnetic field component (e.g., Bx1, Bx2) of a magnetic field generated by the shaft when a torque is applied to the shaft. The first substrate, the second substrate, and the third substrate are incorporated into a single packaged device. The first magnetic sensor and the second magnetic sensor are spaced apart from each other by a predefined distance (e.g., on the order of about 1.5 mm to 25.0 mm). The processing circuit is configured to determine the paired differences between the measured field components, and to output a signal or value indicating the torque applied to the shaft (e.g., substantially proportional to the torque applied to the shaft).

[0198] It is advantageous that the sensor device is provided as a single package, because this ensures accurate distances between sensor locations, and because this simplifies mounting of the packaged device relative to the shaft, rather than mounting separate sensors.

[0199] A major advantage is that the sensor device comprises at least three separate semiconductor substrates, since these semiconductor substrates can be manufactured separately, for example using different materials and / or using different technologies or processes, and / or using different "technology-scalings". This allows, for example, combining a processing circuit implemented in one material and / or in one technology node with a sensor implemented in another material and / or in another technology node. This also allows, for example, combining a processing circuit implemented in CMOS technology with a sensor implemented in GaAs or InAs or another compound semiconductor material from the III-V group. The magnetic sensitivity of such sensors is typically much higher than that of CMOS sensors.

[0200] The main advantage of this device is that it allows to "shrink" a substrate (eg, a processing substrate) without changing the position and / or size of the sensors, as would be the case if they were integrated on the same semiconductor substrate as the processing circuitry.

[0201] Various magnetic sensor devices can be used, such as:

[0202] (a) If Figures 1A to 5 or a wafer level packaged device as described in more detail in

[0203] (b) A magnetic sensor device in which the sensor substrate is stacked on top of or below a first substrate, which is mounted on a lead frame, e.g. FIG. 6A to FIG. 6C as shown in the figure; or

[0204] (c) A magnetic sensor device comprising a lead frame, wherein each of the first substrate, the second substrate and the third substrate is directly mounted on the lead frame, e.g. Figure 7 As shown in the figure;

[0205] Or a variation of (a) or (b) or (c).

[0206] The present invention proposes various axes and various arrangements of sensor devices relative to the axes, for example Figures 9 to 19 As shown in the figure.

[0207] Reference is now made to the drawings.

[0208] Figure 1A and Figure 1B An illustrative example of a magnetic sensor device 100 is shown. Figure 1A shows a plan view, and Figure 1B Shows Figure 1A Cross-sectional view of the magnetic sensor device along line AA.

[0209] The device 100 comprises three separate semiconductor substrates: a first substrate 109, also referred to herein as a "main substrate", and two sensor substrates 106a, 106b. The sensor substrates each include a magnetic sensor (not explicitly shown).

[0210] The three substrates are surrounded by a mold compound 101 (eg, epoxy resin) and held in place by means of the mold compound 101 , but the present invention is not limited thereto.

[0211] To keep the description simple, it will be assumed that each sensor is a single horizontal Hall element, but of course, the present invention is not limited to this and may include other magnetic sensors, or two connected horizontal Hall elements, or multiple Hall elements connected in series or parallel (optionally with an IMC), or one or more vertical Hall elements, or a Wheatstone bridge with at least one MR element, etc. As is known in the art, a horizontal Hall element typically has two "excitation nodes" where a voltage or current is applied; and two "output nodes" where an output signal (e.g., an output voltage) can be measured, thereby requiring a total of four contacts. Similarly, a Wheatstone bridge also has two excitation nodes and two output nodes, and thereby also requires four contacts. Other magnetic sensors (e.g., an IMC with two horizontal Hall elements) may have more than four contacts, as is known in the art. In Figure 1A In the example of FIG. 1 , sensor substrate 106a has four contacts (e.g., in the form of pads 107a), and sensor substrate 106b has four contacts (e.g., in the form of pads 107b). Of course, in other embodiments, the number of contacts may be greater than four, or less than four (e.g., three).

[0212] The four contacts 107a of the first sensor substrate 106a are electrically connected to the four contacts 110a of the main substrate 109 by means of four electrical interconnects 102a implemented in one or more redistribution layers (RDL) (also referred to herein as "RDL stack"). Similarly, the four contacts 107b of the second sensor substrate 106b are electrically connected to the four contacts 110b of the main substrate 109 by means of four electrical interconnects 102b implemented in the one or more RDL layers. In the case of a horizontal Hall element, the main substrate 109 can provide a bias voltage or bias current through two of these contacts, and the sensor signal can be read through the other two contacts. However, of course, more complex biasing and readout schemes can also be used (for example, using so-called spin current technology).

[0213] exist Figure 1AIn the example of FIG. 1 , the main substrate 109 also has a plurality of contacts (eg, pads) 110 c leading to a plurality of contact regions 103 via interconnects 102 c formed in at least one RDL layer. The contact regions 103 may be used to form external terminals of the packaged device 100, such as in FIG. Figure 4 (h) and Figure 4 as further described in (j).

[0214] The principles used in device 100 allow different trade-offs to be made between the following conflicting requirements:

[0215] i) providing a (relatively) small CMOS chip (e.g. having a length “L1” smaller than the distance “dx” between sensors);

[0216] ii) measuring magnetic field differences or gradients having relatively large magnitudes (e.g., at least 10 mT) by increasing the distance "dx" between the sensors;

[0217] iii) providing a single packaged device (thereby avoiding external wires);

[0218] In fact, the proposed solution also offers the following (optional) advantages:

[0219] iv) It allows the distance between sensors to be “customized” at the packaging stage without redesigning any of the three substrates. This allows the solution to be optimized for a range of much smaller quantities.

[0220] v) By using different sensor substrates (eg Ga-As or In-As), it is even possible to use sensors with a higher sensitivity than that of CMOS sensors.

[0221] Figure 1B Three semiconductor substrates 109, 106a, 106b are shown arranged adjacent to each other. In a preferred embodiment, the substrates are arranged so that their "active surfaces" are coplanar, even if the first substrate 109 has a thickness (in the Z direction) that is different from the thickness of the sensor substrate. Layers 108a, 111, 108b are passivation layers on top of the first sensor substrate 106a, on top of the first substrate 109, and on top of the second sensor substrate 106b, respectively. Layer 104 is the first passivation layer of the RDL stack, and layer 105 is the second passivation layer of the RDL stack. Tracks 102 are preferably copper tracks or aluminum tracks. They provide good electrical and thermal contact between the contact areas (e.g., pads) 107a, 107b of the sensor substrate and the contact areas (e.g., pads) 110a, 110b of the main substrate 109. The packaged device 100 may have a shape that is primarily rectangular (as viewed in a direction perpendicular to the substrate).

[0222] exist Figure 1A and Figure 1B In the example shown in FIG. 1 , the first substrate 109 is located substantially in the middle between the two sensor substrates 106 a , 106 b , but this is not absolutely necessary for the invention to work.

[0223] Figure 2 yes Figure 1A and Figure 1B This is not a primary aspect of the invention but is provided for completeness.

[0224] In the example shown, the packaged device 200 includes three substrates: a first substrate 209 including at least a processing circuit 201 ; a second substrate 206a including a first magnetic sensor S1 ; and a third substrate 206b including a second magnetic sensor S2 .

[0225] exist Figure 2 In the example shown in , the first substrate 209 further includes a bias and readout circuit 210, which is configured to provide a first bias voltage Vbias1 (Vbias 1) or a first bias current to the first sensor substrate 206a, and to provide a second bias voltage Vbias2 (Vbias 2) or a second bias current to the second sensor substrate 206b. In response, the first sensor substrate 206a provides a first sensor signal s1 to the first substrate 209, and the second sensor substrate 206b provides a second sensor signal s2 to the first substrate 209 for further processing.

[0226] The first substrate may further include one or more of the following: an analog multiplexer, an amplifier for amplifying the first signal s1 and the second signal s2 , an analog-to-digital converter ADC, and the like.

[0227] The first substrate may further comprise a temperature sensor 211 for measuring the temperature of the first substrate 209. The temperature may be used as an indication of the temperature of the first and second sensors S1, S2 and may be used for temperature compensation of the sensor signals. Temperature compensation may be implemented in the analog domain or in the digital domain.

[0228] In certain embodiments, when the magnetic sensor is biased with a known current, the temperature of the sensor substrate may also be estimated by measuring the resulting voltage difference on the supply nodes, and by estimating the resulting power dissipation.

[0229] In some embodiments, the first sensor substrate may further include a first temperature sensor, and the second sensor substrate may further include a second temperature sensor, and the first sensor substrate may further provide a first temperature signal to the main substrate, and the second sensor substrate may further provide a second temperature signal to the main substrate.

[0230] The bias source (e.g., a voltage source or a current source) may be an independent voltage source or a current source, or may be a dependent voltage source or a current source (e.g., as described in more detail in EP3885779(A1), which is incorporated herein by reference in its entirety). For the purpose of understanding the present invention, it is sufficient that the sensor signals (in the analog domain or the digital domain) are temperature corrected before the difference between the sensor signals is calculated. As explained in EP3885779(A1), the difference may be calculated in the analog domain (i.e., before digitization) or in the digital domain (i.e., after digitization). Calculating the difference in the analog domain reduces the risk of saturating the ADC, especially in the presence of external interference fields.

[0231] The processing circuit 201 may include a programmable processor (eg, a programmable DSP (Digital Signal Processor)).

[0232] The processing circuit 201 may also include a non-volatile memory 203 (e.g., flash memory) storing programmable instructions for the programmable processor and optionally also storing at least one constant K. The processing circuit may be further configured to provide an output value derived from the difference signal, for example, the output value is calculated according to the following formula: Output = K. (s1-s2), where s1 is the first sensor signal or a signal derived therefrom (e.g., after amplification, temperature compensation and digitization), and s2 is the second sensor signal or a signal derived therefrom (e.g., after amplification, temperature compensation and digitization), and K is a predefined constant stored in the non-volatile memory.

[0233] In another or further embodiment, the non-volatile memory may store a predefined function f() (e.g., in the form of polynomial coefficients or in the form of a table), and the processing circuit may be further configured to provide an output value as a function of the difference signal, for example, the output value being calculated according to the following formula: Output = f(s1-s2).

[0234] This provides the advantage that the output may be a value of the torque to be measured (eg in Nm).

[0235] In certain embodiments, the sensor substrate is configured to receive a bias voltage and / or bias current from the first substrate and to provide an output of the sensor circuit (eg, an output of a Hall plate or an output of a Wheatstone bridge) to the first substrate for further processing.

[0236] exist Figure 2 In the example shown in , the bias and readout circuit 210 and the optional temperature sensor 211 are implemented on the first substrate 209, but this is not absolutely necessary for the invention to work, and although generally not preferred, at least a portion of the bias and readout circuit can be implemented on the sensor substrate 206a, 206b.

[0237] exist Figure 2 In the example shown in , the first substrate 209 has an optional temperature sensor 211 and the sensor substrate has no temperature sensor, but as explained above, it is also possible to provide a temperature sensor on each of the sensor substrates.

[0238] Figure 3 Shows the production Figure 1A and Figure 1B Flow chart of a method 300 for a magnetic sensor device such as the magnetic sensor device shown in . The method 300 comprises the following steps:

[0239] a) In step 301, a first semiconductor substrate 109 (eg, a CMOS substrate) having an active surface is provided, the active surface comprising at least a processing circuit 201, the processing circuit 201 being configured to determine a difference between signals obtained from two magnetic sensors S1, S2;

[0240] b) In step 302, a second semiconductor substrate (for example, GaAs) having an active surface including the first magnetic sensor S1 is provided, and a third semiconductor substrate (for example, GaAs) having an active surface including the second magnetic sensor S2 is provided;

[0241] c) In step 303, the first semiconductor substrate 109 is arranged at a position between the second semiconductor substrate 106a and the third semiconductor substrate 106b;

[0242] d) In step 304 , the first semiconductor substrate 109 is electrically connected to the second semiconductor substrate 106 a and to the third semiconductor substrate 106 b by means of at least one redistribution layer (RDL), or by means of an RDL stack.

[0243] Figure 4 (a) to Figure 4 (j) A more detailed map showing the production Figure 1A and Figure 1B The various steps of the method of making a magnetic sensor device like the magnetic sensor device shown in .

[0244] Before describing the individual steps, it is important to note that:

[0245] - Figure 4 (g) shows a plan view of line AA passing through both sensor substrates 106a, 106b. Figure 4 (a) to Figure 4 (f) shows a cross-sectional view according to the line AA, and

[0246] - Figure 4 (j) shows a plan view of line BB passing through one sensor substrate 106 a and passing through one terminal contact portion 103 . Figure 4 (h) and Figure 4 (i) shows a cross-sectional view according to the line BB.

[0247] Now the individual steps can be described:

[0248] exist Figure 4 In (a), a carrier substrate 480 (eg, a glass substrate or a metal substrate) is provided.

[0249] exist Figure 4 In (b), three semiconductor substrates are provided, including: a first semiconductor substrate 109 containing at least a processing circuit, a second semiconductor substrate 106a (also referred to as a first sensor substrate) containing at least a first sensor S1, and a third semiconductor substrate 106b (also referred to as a second sensor substrate) containing at least a second sensor S2. The first substrate 109 is preferably a Si substrate processed using a CMOS compatible process. The sensor substrates 106a, 106b may be Si substrates compatible with the CMOS process, or Si substrates that are not compatible with the CMOS process but provide magnetic sensor elements with higher sensitivity than using the CMOS process, or may include compound semiconductor materials selected from the III-V group (such as, for example, Ga-As or In-As). The substrates are placed (e.g., picked up and placed) with their active surfaces facing the carrier substrate 480, and the first substrate 109 is positioned in the region between the sensor substrates 106a, 106b. A temporary bonding material may be used to temporarily bond the substrate to the carrier substrate. Over the active surface of the sensor substrates 106a, 106b there may be a passivation layer 108a, 108b (not shown here in order not to overload the drawing, but see e.g. Figure 1B ), and there may be a passivation layer 111 (eg, Figure 1B ).

[0250] Figure 4 (c) shows the substrate after overmolding with epoxy molding compound 101 and after curing. Figure 4 (b) Structure.

[0251] Figure 4(d) shows the carrier substrate 480 after debonding and cleaning the bonding material. Figure 4 (c) The result is called a "reconstituted wafer". The molding compound provides structural strength.

[0252] An advantage is that the active surfaces of the three substrates lie in the same (virtual) plane, even if the substrates have different thicknesses. This allows many or all of the through-holes of the redistribution RDL layer to have substantially the same length (in a direction perpendicular to the substrates), thereby benefiting their production. Another advantage is that this makes it possible to mount the three substrates at the same distance from an external object in some applications.

[0253] Figure 4 (e) shows the sensor substrate 106a rotated upside down and after providing an electrical isolation layer 104 (e.g., a polyimide layer) and after patterning the isolation layer 104 to create openings to provide contact areas (e.g., pads) 107a on the first sensor substrate 106a and openings to contact areas (e.g., pads) 110a, 110c, 110b on the first substrate 109 and openings to contact areas (e.g., pads) 107b on the second sensor substrate 106b. Figure 4 (d) Structure.

[0254] Figure 4 (f) shows the electrical connection 102c after providing a patterned conductive layer (e.g., by patterning the resist and using copper electroplating) to provide an electrical connection 102a between the contact areas 107a and 110a, and to provide an electrical connection 102b between the contact areas 107b and 110b, and to create an electrical connection 102c. Figure 4 (e) structure, as will be explained further.

[0255] Figure 4 (h) shows the Figure 4 (j) is a cross-sectional view of the same structure except line BB. Figure 4 The left side of (h) Figure 4 The left side of (f) is the same, but the right side is different.

[0256] Figure 4 (i) shows the top passivation layer 105 (eg, a second polyimide layer) after being applied and patterned to form openings providing access to the contact regions 103 formed by the electrical interconnects 102c. Figure 4 (h) Structure. A noble metal (eg, silver or gold) may be provided on top of these contact regions 103, thereby forming external terminals of the packaged device.

[0257] It should be noted that Figure 4 (a) to Figure 4(j) shows only one sensor device, but in fact, the process is performed at the wafer level, which means that Figure 4 (a) to Figure 4 The step shown in (j) forms a relatively large number of sensor devices simultaneously. The method generally also includes a singulation step (eg, by sawing or by laser dicing the wafer into individual sensor devices).

[0258] Figure 5 Another example of a magnetic sensor device 500 is shown, which can be viewed as Figure 1A and Figure 1B A variation of the magnetic sensor device 100 shown in FIG. Figure 5 The sensor device 500 and Figure 1A and Figure 1B The main difference between the sensor device 100 of FIG. 5 is that the sensor device 500 has only four terminals 503. These terminals can be used, for example, to provide a supply voltage (eg, VDD), and a reference voltage (eg, GND), as well as an output port or a communication interface (eg, a serial communication interface).

[0259] exist Figure 5 In certain embodiments of the sensor device 500, the main substrate 509 may further include a temperature sensor configured to measure the temperature of the main substrate, and the processing circuit may be configured to use the temperature as an estimate of the temperature of the sensor substrate and to perform temperature correction of the signal obtained from the sensor based on the single temperature.

[0260] exist Figure 5 In certain embodiments of the sensor device 500, the main substrate 509 may further include two temperature sensors, one temperature sensor T1 being arranged near a contact area (e.g., a pad) connected to the first sensor substrate 506a, and one temperature sensor T2 being arranged near a contact area (e.g., a pad) connected to the second sensor substrate 506b. By arranging the temperature sensors near the contact areas connected to the respective sensor substrates, the measured temperature can be used to estimate the temperature of the sensor substrate, and the signal can be corrected accordingly. This technique allows correction for temperature differences between the two sensor substrates. An advantage is that the temperature sensor is implemented on the main substrate, and in particular by doing so, (i) the area of ​​the (usually more expensive) sensor substrate can be kept small, and (ii) the number of interconnections between the main substrate and the sensor substrate can be kept small.

[0261] exist Figure 5In certain embodiments of the sensor device 500, each sensor substrate further includes a temperature sensor (not shown), and the sensor substrate is further configured to provide a temperature signal to the first substrate, and the processing circuit is further configured to use the measured temperature signal to correct the signal obtained from the magnetic sensor.

[0262] In certain embodiments, when the magnetic sensor is biased with a known current, the temperature of the sensor substrate may also be estimated by measuring the resulting voltage difference on the supply nodes and by estimating the resulting power dissipation.

[0263] The two sensor substrates 506a, 506b may each contain a magnetic sensor (not explicitly shown) capable of measuring a magnetic field component in the Z direction, and the processing circuit may be configured to further process the two sensor signals Bz1, Bz2. Such a sensor device may be used, for example, in Fig. 9 , Fig.11 , Fig.15 , Fig.18 In the torque sensor system shown in FIG.

[0264] The two sensor substrates 506a, 506b may each contain a magnetic sensor (not explicitly shown) capable of measuring a magnetic field component in the X direction, and the processing circuit may be configured to further process the two sensor signals Bx1, Bx2. Such a sensor device may be used, for example, in Fig.10 , Fig.12 , Fig.14 , Fig.17 In the torque sensor system shown in FIG.

[0265] The two sensor substrates 506a, 506b may each contain a magnetic sensor (not explicitly shown) capable of measuring a magnetic field component in the Y direction, and the processing circuit may be configured to further process the two sensor signals By1, By2. Such a sensor device may be used, for example, in Fig.13 , Fig.16 , Fig.19 In the torque sensor system shown in FIG.

[0266] exist Figure 5 In FIG. 1 , the sensor substrate is shown, but the magnetic sensor itself (e.g., horizontal Hall plate, vertical Hall plate, Wheatstone bridge with MR sensor element) is not shown because Figure 5It is not the magnetic sensor elements or structures that are relevant, but rather how the sensor substrates 506a, 506b are interconnected to the main substrate 509. In practice, any suitable magnetic sensor may be used, for example, including only horizontal Hall elements, or only vertical Hall elements, or only MR elements (e.g., AMR or XMR elements), or including GMI sensors. However, since the magnetic field generated by the shaft is typically very weak, the sensor substrates 506a, 506b are preferably made of (non-CMOS-compliant) semiconductor technology that provides higher sensitivity than CMOS sensors.

[0267] It is also worth noting that the sensor substrates 506a, 506b are larger than the magnetic sensors themselves, particularly because a number of contact areas (eg pads) need to be provided to allow the sensor substrates to be connected to the main substrate 509.

[0268] FIG. 6A to FIG. 6C Examples of other magnetic sensor devices 600, 600', 600" that can be used in embodiments of the torque sensor system proposed by the present invention are shown. These sensor devices include: a lead frame, a first semiconductor substrate 609, 609', 609" mounted on the lead frame, and two sensor substrates 606a, 606b; 606a', 606b'; 606a", 606b" mounted on top of or below the first semiconductor substrate 609, 609', 609" and connected thereto by means of bonding wires. The arrangement is then preferably overmolded with a molding compound 601, 601', 601" (for example using epoxy resin) to form a single packaged device.

[0269] FIG. 6A to FIG. 6C The sensor substrate illustrated in FIG. 1 may include various types of magnetic sensors, for example, only horizontal Hall elements, only vertical Hall elements, or only MR elements (for example, similar to the above (about Figure 5 ) described in ).

[0270] In another or further embodiment, FIG. 6A to FIG. 6C The master substrate illustrated in may include non-volatile memory and may include at least one constant value, or a lookup table having values ​​that may be used to convert the magnetic difference signal into a torque value (eg, via interpolation).

[0271] In another or further embodiment, FIG. 6A to FIG. 6CThe first substrate 609, 609', 609" illustrated in the figure may include a temperature sensor for measuring the temperature of the main substrate and using the temperature of the main substrate as an estimate of the temperature of the sensor substrate to correct the signal obtained from the sensor substrate for temperature variations, optionally by further taking into account an estimate of the power consumed by the sensor substrate. The estimate of the power consumed by the sensor substrate may be determined by providing a known bias voltage Vbias (Vbias) and measuring a bias current Ibias (Ibias), whereas the bias voltage Vbias (Vbias) and the bias current Ibias (Ibias) may be determined by providing a known power consumed by the sensor substrate.

[0272] In another or further embodiment, FIG. 6A to FIG. 6C The main substrate 609, 609', 609" illustrated in the figure may include two temperature sensors (schematically indicated by T1, T2), which are respectively arranged near contact areas (e.g., pads) connected to the corresponding sensor substrates, for measuring a temperature indicating the temperature of each sensor substrate, and the processing circuit may be configured to use the two temperature signals to correct the signal obtained from the sensor substrate.

[0273] In another or further embodiment, each sensor substrate may include a temperature sensor, and the sensor substrate may be further configured to provide temperature signals to the first substrate, and the processing circuitry of the first substrate may be further configured to temperature compensate the signals obtained from the magnetic sensors taking into account these temperature signals.

[0274] Figure 7 An example of another magnetic sensor device 700 that can be used in embodiments of the present invention is shown. The sensor device 700 includes: a lead frame 720, a first semiconductor substrate 709 (also referred to as a "main substrate") mounted on the lead frame 720, and two sensor substrates 706a, 706b also mounted on top of the lead frame, so that the first semiconductor substrate 709 is located between the two sensor substrates 706a, 706b on the same side of the lead frame. Then, preferably, the substrate and the bonding wires and a portion of the lead frame are overmolded (not shown for illustration purposes).

[0275] The first substrate 709 may be electrically connected to the first sensor substrate 706a and to the second sensor substrate 706b by means of bonding wires, either directly (as shown) or indirectly via some leads (not shown) connected to the sensor substrate at one location and to a lead frame of the first substrate at another location. This is particularly useful for relatively large values ​​of the distance dx between the sensors S1, S2.

[0276] Figure 7 The lead frame shown in has only a very simple layout, but of course the invention is not limited thereto and other lead frames may also be used.

[0277] exist Figure 7 In the example shown in , the two sensor substrates 706a, 706b are arranged approximately in the middle of the main substrate 709 (in the Y direction), but this is not necessary for the present invention to work. In fact, in some embodiments, it may be better to move the sensor substrates so that they are aligned with the edges of the main substrate 709. By doing so, (for example, in Fig.16 and Fig.17 Center) The sensor will be located closer to the axis.

[0278] Figure 7 The sensor substrate illustrated in FIG. 1 may include various types of magnetic sensors, for example, only horizontal Hall elements, only vertical Hall elements, or only MR elements (for example, similar to the above (about Figure 5 ) as described above).

[0279] In another or further embodiment, FIG. 6A to FIG. 6C The master substrate illustrated in may include non-volatile memory and may include at least one constant value, or a lookup table having values ​​that may be used to convert the magnetic difference signal into a torque value (eg, via interpolation).

[0280] In another or further embodiment, FIG. 6A to FIG. 6C The master substrate illustrated in FIG. 1 may include a temperature sensor for measuring the temperature of the master substrate and using the temperature of the master substrate as an estimate of the temperature of the sensor substrate to correct the signal obtained from the sensor substrate, optionally by further taking into account an estimate of the power consumed by the sensor substrate. The estimate of the power consumed by the sensor substrate may be determined by providing a known bias voltage Vbias (Vbias) and measuring a bias current Ibias (Ibias), whereas the bias voltage Vbias (Vbias) and the bias current Ibias (Ibias) may be determined by providing a known power consumed by the sensor substrate.

[0281] In another or further embodiment, FIG. 6A to FIG. 6C The main substrate illustrated in the figure may include two temperature sensors, which are respectively arranged near contact areas (e.g., pads) connected to corresponding sensor substrates, for measuring temperatures indicating the temperature of each sensor substrate, and can be configured to use the two temperature signals to correct the signals obtained from the sensor substrates, not only for temperature changes, but also for temperature differences between the two sensor substrates.

[0282] In another or further embodiment, each sensor substrate may include a temperature sensor, and the sensor substrate may be further configured to provide temperature signals to the first substrate, and the processing circuitry of the first substrate may be further configured to temperature compensate the signals obtained from the magnetic sensors taking into account these temperature signals.

[0283] certainly, Figures 5 to 7 The embodiments shown in the drawings are merely examples, and variations of these examples may have Figures 5 to 7 other characteristics than those shown in , such as a different number of external terminals, or package pins, or size.

[0284] Fig. 8A and Figure 8B is an abstract representation of a magnetic sensor device that can be used in the torque sensor system proposed by the present invention and in Figures 9 to 19 As described above, the abstract representation can encompass various types of magnetic sensor devices, including three separate semiconductor substrates in a single package, which substrates can be positioned adjacent to each other or on top of each other. At least the following embodiments are contemplated: (a) a wafer-level packaged device, such as Figures 1A to 5 (b) a magnetic sensor device in which the sensor substrate is stacked on top of or below a first substrate, the first substrate being mounted on a lead frame, for example, as FIG. 6A to FIG. 6C (c) a magnetic sensor device comprising a lead frame, wherein each of the first substrate, the second substrate and the third substrate is directly mounted on the lead frame, for example, Figure 7 As shown in the figure.

[0285] The main purpose of this abstract representation is to show that the device has a first magnetic sensor S1 and a second magnetic sensor S2 spaced apart by a predefined distance dx in the X direction. The abstract representation of the side view or top view allows to clearly specify the magnetic sensor device relative to the following Figures 9 to 19 The position and orientation of shafts in the torque sensor system described in and its variations.

[0286] Figures 9 to 19 An illustrative example of a magnetoelastic torque sensor system proposed by the present invention is shown, which uses a single packaged sensor device including three semiconductor substrates, for example, as shown in FIG. Figure 7 As described above, in these figures, the magnetic sensor device will be Fig. 8A and Figure 8B For illustration purposes, the magnetic sensor device may be an abstract representation of FIG. Figure 7 Any sensor device or variant thereof described in the sensor device. Therefore, even if Figures 9 to 19 The two magnetic sensors S1, S2 of the magnetic sensor device shown in FIG. 1 are shown adjacent to a first substrate labeled “main”, but the present invention is not limited thereto and also encompasses embodiments in which the two sensor substrates are mounted on top of or below the main substrate (e.g., as shown in FIG. 1 ). FIG. 6A to FIG. 6C Importantly for the present invention, the magnetic sensor device is a single packaged device that includes three semiconductor substrates (i.e., not a single, monolithic semiconductor substrate that includes the processing circuitry and the magnetic sensor), regardless of whether the first semiconductor substrate is mounted between the second and third semiconductor substrates (e.g., as shown in FIGS. 1 to 3 ). Figure 5 or Figure 7 ), or whether the sensor substrate is mounted on top of or below the first substrate (e.g., as shown in FIG. 6A to FIG. 6C In all these embodiments, the active surfaces of the three substrates are oriented in parallel.

[0287] Fig. 9 An illustrative embodiment of a magnetoelastic torque sensor system 970 is shown, comprising: a shaft 973 having two axial zones 971, 972 magnetized in opposite circumferential directions, and a magnetic sensor device 900 having two magnetic sensors S1, S2 spaced a predefined distance dx along an X-axis parallel to the shaft 973. As described above, such shafts are known in the art and therefore do not need to be described in more detail here. It can be said that the shaft can include a material that is magnetized itself (e.g., a steel alloy), or the shaft can include one or more magnetic rings fixedly mounted to the shaft so that torque is transmitted from the shaft to the rings.

[0288] The sensor device 900 is oriented so that the normal (Z) of the substrate is oriented radially with respect to the axis 973. The two sensors S1, S2 are located at axial positions near the edges (or ends) 975, 977 of the magnetized regions 971, 972, and the two sensors S1, S2 measure magnetic field components Br1, Br2 oriented in the radial direction of the axis. These magnetic field components may also be referred to as Bz1, Bz2 in a Cartesian coordinate system connected to the sensor device 900, where the X axis is defined by a virtual line passing through the two sensors S1, S2, the Z axis is perpendicular to the three substrates, and the Y axis is perpendicular to the X axis and the Z axis.

[0289] Each of sensor S1 and sensor S2 may include one or more horizontal Hall elements (preferably without an integrated magnetic concentrator), for example, only one horizontal Hall element, or two horizontal Hall elements connected in series or in parallel, or four horizontal Hall elements (for example, two horizontal Hall elements biased orthogonally with respect to each other).

[0290] Assuming that the first axial zone 971 has an axial length L1, and the second axial zone 972 has a second axial length L2, and the two axial zones are separated by a distance L3, the distance dx between the centers of the two sensors S1, S2 is preferably equal to (L1+L3), with a tolerance margin of ±10% or ±5% or ±2%. Preferably, the first sensor S1 and the second sensor S2 are slightly offset from the corresponding edges (or ends) 975, 977 of the magnetized zones 971, 972 by a distance ε, the distance ε having a value in the range of 0% to 20% of L1, or having a value in the range of 3% to 15% of L1 (for example, equal to about 10% of L1), to reduce the effects of mounting position offset (for example, axial mounting offset), and / or to allow easier mechanical assembly. Fig. 9 In FIG. 1 , the offset is inward (ie, toward the middle of the magnetized region), but the invention is not limited thereto, and an outward offset is also possible.

[0291] The processing circuit of the magnetic sensor device 900 is configured to determine the difference signal ΔBz between the magnetic field components Bz1 , Bz2 according to the following formula:

[0292] ΔBz=(Bz1-Bz2), and is used to output a signal or value indicative of the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f9(ΔBz), where f9 is a predefined function, for example, a third-order, second-order or first-order polynomial function of (ΔBz). The function can be stored in a non-volatile memory of the processing device in a suitable manner, for example, by means of coefficients of the polynomial function or in the form of a lookup table. By determining the signal indicative of the torque as a function of the magnetic field difference, the influence of external interference fields is greatly reduced or even eliminated.

[0293] In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBz, for example, according to the formula T=K9×(ΔBz), where K9 is a predefined constant, which can be determined, for example, by a calibration test performed during production and can be written into the non-volatile memory inside the sensor device 900. Figures 1A to 4 In the case of producing the sensor device in the manner described in , the value of K9 can be written into the non-volatile memory at the wafer level before cutting or sawing the wafer.

[0294] The sensor device 900 is preferably mounted relative to the shaft 973 so that the distance d1 between the outer surface of the shaft and the sensor elements S1, S2 is less than 10.0 mm, or less than 8 mm, or less than 5.0 mm. In a preferred embodiment, the radial distance "g" between the shaft and the packaged device 900 is at least 0.1 mm, or at least 0.3 mm, or at least 0.5 mm. The radial distance d1 between the shaft and the active surface of the sensor can be at least 0.2 mm, or at least 0.4 mm, or at least 0.5 mm, or at least 0.8 mm, for example, equal to about 1.0 mm, or equal to about 2.0 mm, or equal to about 3.0 mm.

[0295] exist Fig. 9 In a variant (not shown), the device is mounted "upside down", ie the device 900 is oriented so that the active surface of the sensor substrate is oriented towards the axis. This may allow the distance "d1" to be reduced.

[0296] exist Fig. 9 In a variant (not shown), the shaft has only one axial zone magnetized in the circumferential direction, for example, zone 971 is present and zone 972 is absent. In this case, the first sensor S1 will still be positioned relative to the axial zone 971, such as Fig. 9 , and the first sensor S1 will still measure a signal Bz1 indicative of the magnetic field caused by the torque plus the external disturbance field (if present), while the second sensor S2 will only measure the external disturbance field (if present). This embodiment offers the advantage that the shaft is easier to produce, but the amplitude of the difference signal ΔBz will typically only be Fig. 9 The signal-to-noise ratio (SNR) of the signal will be half that of Fig. 9 The signal-to-noise ratio is slightly worse. In this case, the formula T = K × (ΔBz) can also be used, but the value of K is usually Fig. 9 Twice the value of K9.

[0297] Fig.10 An illustrative embodiment of a magnetoelastic torque sensor system 1070 is shown, which can be viewed as a magnetoelastic torque sensor system 1070. Fig. 9 A variation of the system 900 shown in FIG. 1000 includes a Fig. 9 The magnetic sensor device 1000 includes an axis 1073 which is the same as the axis 973 of the magnetic sensor device 1000 , and the two magnetic sensors S1 , S2 are spaced apart by a predefined distance dx along an X-axis line parallel to the axis 1073 .

[0298] The sensor device 1000 is oriented so that the normal (Z) of the substrate is oriented radially with respect to the axis 1073. The two sensors S1, S2 are located at an axial position near the middle of the magnetized regions 1071, 1072. The two sensors S1, S2 measure magnetic field components Ba1, Ba2 oriented in the axial direction of the axis 1073. These magnetic field components may also be referred to as Bx1, Bx2 in a Cartesian coordinate system connected to the sensor device 1000.

[0299] Each of sensor S1 and sensor S2 may include an integrated magnetic concentrator and two horizontal Hall elements arranged near the periphery of the IMC and located on the X-axis, or may include one or more vertical Hall elements oriented with their axes of maximum sensitivity oriented in the X-direction, or may include one or more magnetoresistive (MR) elements arranged to measure magnetic field components oriented in the X-direction.

[0300] Assuming that the first axial zone 1071 has an axial length L1, and the second axial zone 1072 has a second axial length L2, and the two axial zones are separated by a distance L3, preferably the distance dx between the centers of the two sensors S1, S2 is equal to [L3+(L1+L2) / 2], with a tolerance margin of ±10% or ±5% or ±2%. Preferably, the first sensor S1 and the second sensor S2 are offset from the respective edges (or ends) of the magnetized zones 1071, 1072 by a distance μ, and the distance μ has a value in the range of 40% to 60% of L1, or in the range of 45% to 55% of L1 (e.g., equal to about 50% of L1).

[0301] The processing circuit of the magnetic sensor device 1000 is configured to determine the difference signal ΔBx between the magnetic field components Bx1, Bx2 according to the formula ΔBx=(Bx1-Bx2), and to output a signal or value indicative of the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f10(ΔBx), where f10 is a predefined function, for example, a third-order, second-order or first-order polynomial function of (ΔBx). The function can be stored in a non-volatile memory of the sensor device 1000 in an appropriate manner, for example, by means of coefficients of the polynomial function or in the form of a lookup table. By determining the signal indicative of the torque as a function of the magnetic field difference, the influence of external interference fields is greatly reduced or even eliminated.

[0302] In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBx, for example according to the formula T=K10×(ΔBx), where K10 is a predefined constant, which can be written into the non-volatile memory inside the sensor device 1000 (for example, during production or during a calibration process).

[0303] If targeted Fig. 9 As mentioned, similar distances d1 and g may be used.

[0304] exist Fig.10 In a variant (not shown), the device is mounted "upside down", ie the device 1000 is oriented so that the active surface of the sensor substrate is oriented towards the axis. This may allow the distance "d1" to be reduced.

[0305] exist Fig.10 In a variant (not shown), the shaft has only one axial zone magnetized in the circumferential direction, for example, zone 1071 is present and zone 1072 is absent. In this case, the first sensor S1 will still be positioned relative to the axial zone 1071, such as Fig.10 , and the first sensor S1 will still measure the signal Bx1 indicating the magnetic field caused by the torque plus the external disturbance field (if present), while the second sensor S2 will only measure the external disturbance field (if present). This embodiment provides the advantage that the shaft is easier to produce, but the amplitude of the difference signal ΔBx will typically only be Fig.10 The signal-to-noise ratio (SNR) of the signal will be half that of Fig.10 The signal-to-noise ratio is slightly worse. In this case, the formula T = K × (ΔBx) can also be used, but the value of K is usually Fig.10 Twice the value of K10.

[0306] Fig.11 An illustrative embodiment of a magnetoelastic torque sensor system 1170 is shown, comprising: a shaft 1173 having only one axial zone 1171 magnetized in a circumferential direction (or having two magnetized zones but only one is used), and a magnetic sensor device 1100 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line parallel to the shaft 1173.

[0307] Fig.11 The torque sensor system 1100 can be considered as Fig. 9 Another variation of a torque sensor system is shown in FIG. 1 , and much of what is explained above can also be applied here.

[0308] The sensor device 900 is oriented so that the normal (Z) to the substrate is oriented radially about the axis 1173. The two sensors S1, S2 are located at axial positions near the edges (or ends) 1175, 1176 of the magnetized region 1171, and preferably at axial positions between those edges.

[0309] The magnetic field components measured by sensors S1 , S2 may be referred to as Br1 , Br2 relative to axis 1173 , or as Bz1 , Bz2 relative to sensor device 1100 .

[0310] The magnetized region 1171 has an axial length L1. Preferably, the first sensor S1 and the second sensor S2 are slightly offset from the edge of the magnetized region 1171 by a distance ε, the distance ε having a value in the range of 0% to 20% of L1, or having a value in the range of 3% to 15% of L1 (e.g., equal to about 10% of L1), to reduce the influence of the mounting position offset. Preferably, the distance dx between the centers of the two sensors S1, S2 is equal to (L1-2×ε), with a tolerance margin of ±10%, or ±5%, or ±2%. Alternatively, the sensors are shifted outward above the offset ε, in which case the distance dx between the centers of the two sensors S1, S2 is approximately equal to (L1+2×ε), with a tolerance margin of ±10%, or ±5%, or ±2%.

[0311] The processing circuit of the magnetic sensor device 1100 is configured to determine the difference signal ΔBz between the magnetic field components Bz1, Bz2 according to the formula ΔBz=(Bz1-Bz2), and to output a signal or value indicative of the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f11(ΔBz), where f11 is a predefined function of the magnetic field difference. In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBz, for example according to the formula T=K11×(ΔBz), where K11 is a predefined constant. The value of K11 can be hard-coded, or the value of K11 can be stored in a non-volatile memory inside the sensor device 1100 (for example, during production or during a calibration process).

[0312] Similar distances between the axis and the sensor device as described above apply here as well. Fig.11 In a variation (not shown), the device is mounted "upside down".

[0313] Fig.12 An illustrative embodiment of a magnetoelastic torque sensor system 1270 is shown, comprising: a shaft 1273 having only one axial zone 1271 magnetized in a circumferential direction (or having two magnetized zones but one is used), and a magnetic sensor device 1200 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line oriented radially with respect to the shaft 1273.

[0314] Fig.12 The torque sensor system 1200 can be considered as Fig.10A variation of the torque sensor system 1000 in which the sensor device is rotated 90° about its Y-axis and then rotated 90° about its X-axis, and in which the shaft has only one magnetized region, and in which the sensor device is shifted to an axial position near an edge 1275 of the magnetized region 1273.

[0315] The sensor device 1200 is preferably oriented so that the normal (Z) of the substrate is oriented in the circumferential direction about the axis 1273. The two sensors S1, S2 are located in an axial position between the two edges of the magnetized zone 1271, relatively close to one of the edges 1275. In a variant (not shown), the axial position of the sensors is located slightly outside the magnetized zone 1271.

[0316] The magnetic field components measured by sensors S1 , S2 may be referred to as Br1 , Br2 relative to axis 1273 , or as Bx1 , Bx2 relative to sensor device 1200 .

[0317] The magnetized zone 1271 has an axial length L1. Preferably, the axial position of the first sensor S1 and the second sensor S2 is slightly offset from one of the edges 1275 of the magnetized zone 1271 by a distance ε having a value in the range of 0% to 20% of L1, or having a value in the range of 3% to 15% of L1 (e.g., equal to about 10% of L1) to reduce the effects of mounting position offset and / or allow easier mechanical assembly. Fig.11 In FIG. 1 , the offset is inward (ie, toward the middle of the magnetized region), but the invention is not limited thereto, and an outward offset is also possible.

[0318] The distance dx between the centers of the two sensors S1, S2 can be selected substantially independently of the length L1, but can be selected based on the distance "g" between the shaft 1273 and the package of the sensor device 1200, and thus based on the distances d1, d2 between the shaft and the first sensor S1 and the second sensor S2. For a given torque applied to the shaft, the smaller the value of d1 and the larger the value of d2, the larger the value of ΔBx.

[0319] In a preferred embodiment, the radial distance "g" between the shaft and the packaging device 900 is at least 0.1 mm, or at least 0.3 mm, or at least 0.5 mm, and at most 5.0 mm. The radial distance d1 between the shaft and the sensor device 1200 is preferably at most 5.0 mm, or at most 4.0 mm, or at most 3.0 mm, or at most 2.0 mm, or at most 1.0 mm. Preferably, the distance dx between the sensor S1 and the sensor S2 is at least 2 times d1 (dx ≥ 2 × d1), or at least 3 times d1 (dx ≥ 3 × d1), or at least 4 times d1 (dx ≥ 4 × d1), or at least 5 times d1 (dx ≥ 5 × d1).

[0320] The processing circuit of the magnetic sensor device 1200 is configured to determine the difference signal ΔBx between the magnetic field components Bx1, Bx2 according to the formula ΔBx=(Bx1-Bx2), and to output a signal or value indicating the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f12(ΔBx), where f12 is a predefined function of the magnetic field difference ΔBx. In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBx, for example according to the formula T=K12×(ΔBx), where K12 is a predefined constant. The value of K12 can be stored in a non-volatile memory inside the sensor device 1200 (for example, during production or during a calibration process).

[0321] Fig.13 An illustrative embodiment of a magnetoelastic torque sensor system 1370 is shown, comprising: a shaft 1373 having only one axial zone 1371 magnetized in a circumferential direction (or having two magnetized zones but only one is used), and a magnetic sensor device 1300 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line oriented radially with respect to the shaft 1373.

[0322] Fig.13 The torque sensor system 1300 may at first glance appear to be Fig.12 A variation of the torque sensor system 1200, in which the sensor device is shifted to an axial position toward the middle of the magnetized region 1371, but in fact the sensor device is a different sensor device because the sensors S1, S2 of the sensor device 1300 are configured to measure magnetic field components Ba1, Ba2 parallel to the axis, or to measure magnetic field components By1, By2 relative to the sensor device.

[0323] Each of sensor S1 and sensor S2 may include an integrated magnetic concentrator and two horizontal Hall elements arranged near the periphery of the IMC and located on an imaginary line parallel to the Y axis, or may include one or more vertical Hall elements oriented with their axes of maximum sensitivity oriented in the Y direction, or may include one or more magnetoresistive (MR) elements arranged to measure magnetic field components oriented in the Y direction.

[0324] The sensor device 1300 is preferably oriented so that the normal (Z) of the substrate is oriented in the circumferential direction about the axis 1373. The two sensors S1, S2 are located at an axial position between the two edges 1375, 1376 of the magnetizing zone 1371, close to the middle of the magnetizing zone 1372. More specifically, if the magnetizing zone 1371 has an axial length L1, the axial position of the first sensor S1 and the second sensor S2 is preferably offset from one of the edges 1375 of the magnetizing zone 1371 by a distance μ, and the distance μ has a value in the range of 40% to 60% of L1, or has a value in the range of 45% to 55% of L1 (e.g., equal to about 50% of L1).

[0325] The distance dx between the centers of the two sensors S1, S2 can be selected substantially independently of the length L1, but can be selected based on the distance between the shaft and the package of the sensor device 1300, and thus based on the distances d1, d2 between the shaft and the first sensor S1 and the second sensor S2. For a given torque applied to the shaft, the smaller the value of d1 and the larger the value of d2, the larger the value of ΔBy. Fig.12 As mentioned, similar distances "d1" and "g" and "dx" may be used.

[0326] The processing circuit of the magnetic sensor device 1300 is configured to determine the difference signal ΔBy between the magnetic field components By1, By2 according to the formula ΔBy=(By1-By2), and to output a signal or value indicating the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f13(ΔBy), where f13 is a predefined function of the magnetic field difference. In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBy, for example according to the formula T=K13×(ΔBy), where K13 is a predefined constant. The value of K13 can be stored in a non-volatile memory inside the sensor device 1300 (for example, during production or during a calibration process).

[0327] Fig.14 An illustrative embodiment of a magnetoelastic torque sensor system 1470 is shown, comprising: a shaft 1473 having only one axial zone 1471 magnetized in a circumferential direction (or having two magnetized zones but only one is used), and a magnetic sensor device 1400 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line oriented radially with respect to the shaft 1473.

[0328] Fig.14 The torque sensor system 1400 can be considered as Fig.12 A variation of torque sensor system 1200 in which the sensor device is rotated 90° about its X-axis.

[0329] exist Fig.14 , the sensor device 1400 is oriented such that the normal (Z) of the substrate is oriented in the axial direction of the axis 1473. Fig.12 Everything else described for the torque sensor system and its variants also applies here.

[0330] exist Fig.12 and Fig.14 In further variations, the sensor device 1400 is rotated around the X axis by an arbitrary angle. In all of these embodiments, the same magnetic field components Br1, Br2 (about the axis), or Bx1, Bx2 (about the sensor device 1400) will be measured. In all of these embodiments, the torque can be calculated according to the formula T=f14(ΔBx) as, for example, T=K14×(ΔBx), where K14 is a predefined constant that can be stored in a non-volatile memory.

[0331] Fig.15 An illustrative embodiment of a magnetoelastic torque sensor system 1570 is shown, comprising: a shaft 1573 having only one axial zone 1571 magnetized in a circumferential direction (or having two magnetized zones but only one is used), and a magnetic sensor device 1500 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line oriented radially with respect to the shaft 1573.

[0332] Fig.15 The torque sensor system 1570 may at first glance appear to be Fig.13 A variation of the torque sensor system 1370 in which the sensor device is rotated 90° relative to the X-axis, but in fact the sensor device is a different sensor device because the sensors S1, S2 of the sensor device 1500 are configured to measure the magnetic field components Ba1, Ba2 parallel to the axis, or to measure the magnetic field components Bz1, Bz2 relative to the sensor device (i.e. in a direction perpendicular to the substrate).

[0333] The sensor device 1500 is preferably oriented so that the normal (Z) of the substrate is oriented in the axial direction about the axis 1573. The two sensors S1, S2 are located at an axial position between the two edges 1575, 1576 of the magnetizing zone 1571, close to the middle of the magnetizing zone 1571. More specifically, if the magnetizing zone 1571 has an axial length L1, the axial position of the first sensor S1 and the second sensor S2 is preferably offset from one of the edges 1575 of the magnetizing zone 1571 by a distance μ, and the distance μ has a value in the range of 40% to 60% of L1, or has a value in the range of 45% to 55% of L1 (e.g., equal to about 50% of L1).

[0334] The distance dx between the centers of the two sensors S1, S2 may be selected substantially independently of the length L1, but may be selected based on the distance "g" between the shaft and the package of the sensor device 1500, and thereby based on the distances d1, d2 between the shaft and the first sensor S1 and the second sensor S2. For a given torque applied to the shaft, the smaller the value of d1 and the larger the value of d2, the larger the value of ΔBz will be.

[0335] For the value of the radial distance "g" and the value of the radial distance "d1", and for Fig.12 The values ​​mentioned for the ratio (dx / d1) also apply here.

[0336] The processing circuit of the magnetic sensor device 1500 is configured to determine the difference signal ΔBz between the magnetic field components Bz1, Bz2 according to the formula ΔBz=(Bz1-Bz2), and to output a signal or value indicating the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f15(ΔBz), where f15 is a predefined function of the magnetic field difference. In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBz, for example according to the formula T=K15×(ΔBz), where K15 is a predefined constant. The value of K15 can be stored in a non-volatile memory inside the sensor device 1500.

[0337] Fig.16 An illustrative embodiment of a magnetoelastic torque sensor system 1670 is shown, comprising: a shaft 1673 having two axial regions 1671 , 1672 magnetized in opposite circumferential directions, and a magnetic sensor device 1600 having two magnetic sensors S1 , S2 spaced apart a predefined distance dx along an X-axis line parallel to the shaft 1673 .

[0338] Fig.16 The torque sensor system 1600 may at first glance appear to be Fig. 9 A variation of the torque sensor system 900, in which the sensor device is rotated 90° relative to the X-axis, but in fact the sensor device is a different sensor device because the sensors S1, S2 of the sensor device 1600 are configured to measure magnetic field components Br1, Br2 oriented radially about the axis, or to measure magnetic field components By1, By2 relative to the sensor device (i.e. in a direction parallel to the substrate and perpendicular to the X-axis defined by the two sensors S1, S2).

[0339] Each of sensor S1 and sensor S2 may include an integrated magnetic concentrator and two horizontal Hall elements arranged near the periphery of the IMC and located on an imaginary line parallel to the Y axis, or may include one or more vertical Hall elements oriented with their axes of maximum sensitivity oriented in the Y direction, or may include one or more magnetoresistive (MR) elements arranged to measure magnetic field components oriented in the Y direction.

[0340] The sensor device 1600 is oriented such that the normal (Z) to the substrate is oriented in a circumferential direction about the axis 1673. The two sensors S1 , S2 are located at axial positions near the edges 1675, 1677 of the magnetized regions 1671 , 1672.

[0341] More specifically, if the first axial zone 1671 has an axial length L1, and the second axial zone 1672 has a second axial length L2, and the two axial zones are separated by a distance L3, then preferably the distance dx between the centers of the two sensors S1, S2 is equal to (L1+L3), with a tolerance margin of ±10%, or ±5%, or ±2%. Preferably, the first sensor S1 and the second sensor S2 are slightly offset from the respective edges 1675, 1677 of the magnetized zones 1671, 1672 by a distance ε, the distance ε having a value in the range of 0% to 20% of L1, or having a value in the range of 3% to 15% of L1 (e.g., equal to about 10% of L1), to reduce the influence of the mounting position offset. Fig.16 In the embodiment, the sensor is positioned at an axial position slightly offset "inward" with respect to the edges 1675, 1677, i.e., towards the middle of the magnetized regions 1671, 1672. In a variant, the two axial positions are slightly shifted "outward" by a distance ε with respect to the edges 1675, 1677 (i.e., away from the middle of the magnetized regions 1671, 1672).

[0342] The processing circuit of the magnetic sensor device 1600 is configured to determine the difference signal ΔBy between the magnetic field components By1, By2 according to the formula ΔBy=(By1-By2), and to output a signal or value indicating the torque applied to the shaft. The processing circuit can, for example, be configured to determine the value T of the torque applied to the shaft as a predefined function of the difference signal, for example according to the formula T=f16(ΔBy), where f16 is a predefined function of (ΔBy). In a preferred embodiment, the torque T is calculated as a value proportional to the magnetic field difference ΔBy, for example according to the formula T=K16×(ΔBy), where K16 is a predefined constant, which can be stored in a non-volatile memory inside the sensor device 1600.

[0343] The sensor device 900 is preferably mounted so that the radial distance "g" between the shaft and the package device 900 is at least 0.1 mm, or at least 0.3 mm, or at least 0.5 mm, and at most 5.0 mm. The radial distance d1 between the shaft and the sensor device 1600 is preferably at most 5.0 mm, or at most 4.0 mm, or at most 3.0 mm, or at most 2.0 mm, or at most 1.0 mm.

[0344] exist Fig.16 In a variant (not shown), the shaft has only one axial zone magnetized in the circumferential direction, for example, zone 1671 is present and zone 1672 is absent. In this case, the first sensor S1 will still be positioned relative to the axial zone 1671, as shown in FIG. Fig.16 As shown in the figure (or in Fig.16 ) and the first sensor S1 will still measure the signal By1 indicating the magnetic field caused by the torque plus the external disturbance field (if present), while the second sensor S2 will only measure the external disturbance field (if present). This variant has the advantage that it is easier to produce a shaft 1673 with only one axial magnetized zone, but the amplitude of the difference signal ΔBy will generally be smaller (e.g., only Fig.16 The signal-to-noise ratio (SNR) of the signal ΔBy will be Fig.16 The signal-to-noise ratio of the torque sensor system is slightly worse. In this case, the formula T = K × (ΔBy) can also be used, but the value of K will usually be Fig.16 Twice the value of K16.

[0345] exist Fig.16 In a further variation (not shown), the sensor device 1600 is rotated by an arbitrary angle around an axis parallel to the Y axis and passing through the first sensor S1. In this case, the formula T=K×(ΔBy) can also be used.

[0346] Fig.17 An illustrative embodiment of a magnetoelastic torque sensor system 1770 is shown, comprising: a shaft 1773 having two axial regions 1771 , 1772 magnetized in opposite circumferential directions, and a magnetic sensor device 1700 having two magnetic sensors S1 , S2 spaced apart a predefined distance dx along an X-axis line parallel to the shaft 1773 .

[0347] Fig.17 The torque sensor system 1700 can be considered as Fig.10 A variation of the torque sensor system 1000 in which the sensor device is rotated 90° about its X-axis. However, preferably, the sensor substrates of the sensor device 1700 are slightly shifted relative to the main substrate so that they are located closer to the axis 1773 (for a given distance between the packaged device and the axis).

[0348] exist Fig.17 , the sensor device 1700 is oriented so that the normal (Z) of the substrate is oriented in the circumferential direction of the axis 1773 (i.e., in the direction tangential to a virtual circle concentric with the axis of the axis 1773). Fig.10 All other contents described for the torque sensor system of the present invention also apply here. For example, the torque applied to the shaft can be calculated as a function of the difference ΔBx, for example according to the formula T=f17(ΔBx), where f17 is a predefined function, for example, calculated as K17×ΔBx, where K17 is a predefined constant, and K17 can be stored in the non-volatile memory of the sensor device 1700.

[0349] exist Fig.17 In a variant (not shown), the shaft has only one axial zone magnetized in the circumferential direction, for example, zone 1771 is present and zone 1772 is absent. In this case, the first sensor S1 will still be positioned relative to the axial zone 1771, such as Fig.17 This variant has the advantage that it is easier to produce a shaft with only one axial magnetization zone, but the amplitude of the difference signal ΔBx will generally be smaller (e.g. only Fig.17 The signal-to-noise ratio (SNR) of the signal ΔBx will be Fig.17 The signal-to-noise ratio of the torque sensor system 1700 is slightly worse. In this case, the formula T = K × (ΔBx) can also be used, but the value of K will usually be Fig.17 Twice the value of K17.

[0350] Fig.18 An illustrative embodiment of a magnetoelastic torque sensor system 1870 is shown, comprising: an axis 1873 having two axial regions 1871, 1872 magnetized in the same circumferential direction (e.g., both clockwise or both counterclockwise), and a magnetic sensor device 1800 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line parallel to the axis 1873.

[0351] Fig.18 The torque sensor system 1800 can be considered as Fig. 9A variant of the torque sensor system 900 in which the second axial zone 1872 of the shaft 1873 is magnetized in the same circumferential direction as the first axial zone 1871, and in which the first sensor S1 and the second sensor S2 are either arranged at two axial positions near the inner edges 1875, 1876 of the two axial zones 1871, 1872 (as shown in the figure), in which case the distance dx is preferably equal to about (L3±2×ε), depending on whether the offset is inward or outward; or in which the first sensor S1 and the second sensor S2 are arranged at two axial positions near the outer edges 1877, 1878 of the two axial zones 1871, 1872, in which case the distance dx is preferably equal to about (L1+L3+L2±2×ε). In both cases, the offset ε preferably has a value in the range of 0% to 20% of L1, or a value in the range of 3% to 15% of L1 (e.g. equal to about 10% of L1).

[0352] for Fig. 9 All other contents described for the torque sensor system of the present invention also apply here. For example, the torque applied to the shaft can be calculated as a function of the difference ΔBz, for example according to the formula T=f18(ΔBz), where f18 is a predefined function, for example, calculated as K18×ΔBz, where K18 is a predefined constant, and K18 can be stored in the non-volatile memory of the sensor device 1800.

[0353] exist Fig.18 In a variant (not shown), the shaft has only one axial zone magnetized in the circumferential direction, for example, zone 1871 is present and zone 1872 is absent. In this case, the first sensor S1 will still be positioned relative to the axial zone 1871, as shown in FIG. Fig.18 , and the first sensor S1 will still measure the signal Bz1 indicating the magnetic field caused by the torque plus the external interference field (if present), while the second sensor S2 will only measure the external interference field (if present). In this case, the formula T = K × (ΔBz) can also be used, but the value of K will usually be Fig.18 Twice the value of K18.

[0354] Fig.19 An illustrative embodiment of a magnetoelastic torque sensor system 1970 is shown, comprising: an axis 1973 having two axial regions 1971, 1972 magnetized in the same circumferential direction (e.g., both clockwise or both counterclockwise), and a magnetic sensor device 1900 having two magnetic sensors S1, S2 spaced apart a predefined distance dx along an X-axis line parallel to the axis 1973.

[0355] Fig.19 The torque sensor system 1900 can be considered as Fig.16A variation of the torque sensor system 1600 in which the second axial zone 1972 of the shaft 1973 is magnetized in the same circumferential direction as the first axial zone 1971, and in which the first sensor S1 and the second sensor S2 are either both arranged at two axial positions near the inner edges 1975, 1976 of the two axial zones 1971, 1972 (as shown in the figure), in which case the distance dx is preferably equal to about (L3±2×ε); or in which the first sensor S1 and the second sensor S2 are both arranged at two axial positions near the outer edges 1977, 1978 of the two axial zones 1971, 1972, in which case the distance dx is preferably equal to about (L1+L3+L2±2×ε). In both cases, the offset ε preferably has a value in the range of 0% to 20% of L1, or in the range of 3% to 15% of L1 (e.g. equal to about 10% of L1).

[0356] for Fig.16 All other contents described for the torque sensor system of the present invention also apply here. For example, the torque applied to the shaft can be calculated as a function of the difference ΔBy, for example according to the formula T=f19(ΔBy), where f19 is a predefined function, for example, calculated as K19×ΔBy, where K19 is a predefined constant, and K19 can be stored in the non-volatile memory of the sensor device 1900.

[0357] exist Fig.19 In a variant (not shown), the shaft has only one axial zone magnetized in the circumferential direction, for example, zone 1971 is present and zone 1972 is absent. In this case, the first sensor S1 will still be positioned relative to the axial zone 1971, as shown in FIG. Fig.19 , and the first sensor S1 will still measure the signal By1 indicating the magnetic field caused by the torque plus the external interference field (if present), while the second sensor S2 will only measure the external interference field (if present). In this case, the formula T = K × (ΔBy) can also be used, but the value of K will usually be Fig.19 Twice the value of K19.

[0358] Figures 9 to 19The torque sensor system illustrated in FIG. 1 shows only one magnetic sensor device, but the invention is not limited thereto, and embodiments of the invention may include more than one magnetic sensor device, such as two magnetic sensor devices, which are mounted in the vicinity of the shaft and which are circumferentially spaced apart by an angle (e.g., θ), such as in the range of 165° to 180°. However, another angular position of, for example, at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95° may also be effective. The signals from the two magnetic sensor devices may be combined by one of the magnetic sensor devices, or by an external processor (not explicitly shown), to determine the torque value applied to the shaft.

[0359] In a variation, the torque sensor system includes three magnetic sensor devices mounted in the vicinity of the shaft, the three magnetic sensor devices being circumferentially spaced apart by an angle (e.g., θ) of at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95° (e.g., spaced apart by an angle in the range of 105° to 135°). The signals from the three magnetic sensor devices can be combined by one of the magnetic sensor devices, or by an external processor, to determine a torque value applied to the shaft.

[0360] In another variation, the torque sensor system includes four magnetic sensor devices mounted near the shaft, the four magnetic sensor devices being circumferentially spaced apart by an angle (e.g., θ) of at least 30°, or at least 45°, or at least 60°, or at least 70° (e.g., spaced apart by an angle in the range of 80° to 100°). The signals from the four magnetic sensor devices can be combined by one of the magnetic sensor devices, or by an external processor, to determine a torque value applied to the shaft.

[0361] In any of these variants (these variants include multiple sensor devices that are angularly spaced apart from each other in a circumferential direction around the shaft), the combination of the signals can use parameters determined during a calibration process and stored in a non-volatile memory of the magnetic sensor device. An advantage of using multiple sensor devices is that, in particular in the radial direction of the shaft, mechanical offsets or mechanical play can be reduced or at least partially compensated by combining the signals from these multiple sensor devices.

[0362] Figures 20 to 22BA further magnetoelastic torque sensor system proposed by the present invention is shown, the magnetoelastic torque sensor system comprising: a shaft having three axial zones magnetized in alternating circumferential directions; and one or more magnetic sensor devices, the one or more magnetic sensor devices being arranged in the vicinity of the shaft, each magnetic sensor device having at least two magnetic sensors spaced apart in the axial direction, and each magnetic sensor device optionally also including a processing substrate. A sensor device as described in FIGS. 1 to 8 may be used, but this is not absolutely necessary. For example, if the torque sensor system comprises a plurality of magnetic sensor devices, one of the plurality of magnetic sensor devices may include a processing substrate and two sensor substrates, while the other magnetic sensor devices may require only two sensor substrates. As another example, if the torque sensor system comprises an external processor (e.g., a display and computing device of an electric bicycle), the magnetic sensor device may include only a sensor substrate.

[0363] The processing substrate (if present) may be a CMOS substrate. The sensor substrate may be a compound semiconductor substrate including a material from the III-V group, such as Ga-As or In-As. Each of the sensor substrates may include one or more horizontal Hall elements configured to measure a magnetic field component oriented in a radial direction about an axis.

[0364] Fig. 20 An illustrative embodiment of a magnetoelastic torque sensor system 2070 is shown, comprising: a shaft 2073 having three axial zones, the three axial zones including a first axial zone 2071a magnetized in a first circumferential direction (e.g., clockwise) and a second axial zone 2071b magnetized in a second circumferential direction opposite to the first circumferential direction, and a third axial zone 2071c magnetized in a third circumferential direction opposite to the second circumferential direction. The system further comprises at least one magnetic sensor device 2000 having two magnetic sensors S1, S2 spaced apart by a predefined distance dx along an X-axis parallel to the shaft 2073.

[0365] Fig. 20 The torque sensor system 2000 can be considered as Fig.11 A variation of the torque sensor system 1100 in which the shaft has two further axial sections. Fig.11 All other contents described for the torque sensor system of the present invention also apply here. For example, the torque applied to the shaft can be calculated as a function of the difference ΔBz, for example according to the formula T=f20(ΔBz), where f20 is a predefined function, for example, calculated as K20×ΔBz, where K20 is a predefined constant, and K20 can be stored in the non-volatile memory of the sensor device 2000.

[0366] The first axial region 2071a has a first axial length L1, the second axial region 2071b has a second axial length L2, and the third axial region 2071c has a third axial length L3. Preferably L1 = L2 and L2 = L3.

[0367] The first axial region 2071a is spaced from the second axial region 2071b by up to a distance dA, and the third axial region 2071c is spaced from the second axial region 2071b by up to a distance dB. Preferably, dA is substantially equal to dB, e.g., dA equals dB. The value of dA can be a value in the range from 0.5 mm to 5.0 mm, e.g., equal to about 1.0 mm. The region between the first axial region 2071a and the second axial region 2071b can be a code-free region having an axial length equal to dA. The region between the second axial region 2071b and the third axial region 2071c can be a code-free region having an axial length equal to dB.

[0368] The active surfaces of the sensors S1, S2 are spaced from the shaft by up to a distance ds. The value of ds can be a value in the range from 0.5 mm to 2.5 mm, e.g., equal to about 1.0 mm. Preferably, the value of ds is substantially equal to dA, e.g., ds equals dA.

[0369] The device 2000 can have a package spaced from the shaft by up to a distance g, the distance g also being referred to as the "gap".

[0370] The center of the first sensor S1 is spaced from the center of the second sensor S2 by up to a distance dx. The value of dx can be less than or equal to L2 (i.e., dx ≤ L2). Preferably, the value of dx is less than L2 (i.e., dx < L2). More preferably, dx = L2 - (2×ε), where L2 is the length of the central axial region 2071b and ε is the inward offset from the circular edges 2075, 2076 of the central region.

[0371] In a preferred embodiment, one or more or all of the following statements are true:

[0372] i) dx ≤ L2 or dx < L2, e.g., dx = L2 - (2×ε) and ε > 0;

[0373] ii) dA / dB is a value from 50% to 200%, or from 80% to 125%, or from 90% to 110%;

[0374] iii) ds / dA is a value from 50% to 200%, or from 80% to 125%, or from 90% to 110%;

[0375] In an embodiment, i) dx ≤ L2, and ii) dA / dB is a value from 50% to 200%.

[0376] In an embodiment, i) dx≤L2, and iii) ds / dA is a value from 50% to 200%.

[0377] In an embodiment, i) dx ≤ L2, and ii) dA / dB is a value from 50% to 200%, and iii) ds / dA is a value from 50% to 200%.

[0378] Fig.21 Shown for Fig. 20 , where dA=dB=ds, and L1=L2=L3, but the invention is not limited thereto. The graph shows the value of Bz (expressed in arbitrary units) as a function of axial displacement in the X direction at a radial distance ds from the axis.

[0379] It can be seen from the curve graph that if the two sensors S1 and S2 are spaced apart in the X direction at a position corresponding to a triangle, that is, if dx=L2+d, then the value of (Bz1-Bz2) will be maximum, but the axial mounting position of the sensor device will need to be accurate, because a small shift of the curve to the left or right will cause (Bz1-Bz2) to decrease.

[0380] If the two sensors S1, S2 are spaced apart in the X direction at a position corresponding to a circle, that is, if dx is equal to about L2, then the value of (Bz1-Bz2) will be close to the maximum, but the axial mounting position of the sensor device will be slightly relaxed, because a shift to the left / right will cause the value of Bz1 to increase / decrease (in absolute value) and will cause the value of Bz2 to decrease / increase (in absolute value), but the increase and decrease will not be the same, so there is some compensation, but this compensation is not ideal.

[0381] If the two sensors S1, S2 were spaced apart in the X direction at a position corresponding to a square, that is, if dx was equal to approximately (L2-dA), the value of (Bz1-Bz2) would have an amplitude of approximately 60% of the maximum value, that is, the signal-to-noise ratio would be lost by approximately 1 bit, but the axial mounting position of the sensor device would be greatly relaxed, because a shift to the left / right would cause the value of Bz1 (in absolute value) to increase / decrease and would cause the value of Bz2 (in absolute value) to decrease / increase by approximately the same amount, whereby the compensation is close to ideal.

[0382] Fig.21The dashed line in shows the variation of the value of ΔBz=(Bz1-Bz2) according to the mounting position of the sensor device, where dx=(L2-dA), corresponding to the square. As can be seen, the dashed line has a substantially "flat top", which means that for mounting offsets up to about 33% of L2, the value of ΔBz is substantially constant (e.g., varies less than ±3%). It can be said that this value of dx is optimal because the ratio of the axial offset (±33% about the assumed position offset L2) to the variation of ΔBz (less than ±3%) is maximized. But of course, the present invention will also work if dx is not exactly equal to (L2-dA), but has a value in the range from (L2-2×dA) to (L2+dA), or has a value in the range from (L2-2×dA) to (L2), or has a value in the range from (L2-1.5×dA) to (L2-0.5×dA), or has a value in the range from (L2-1.2×dA) to (L2-0.8×dA). Return to reference Fig. 20 , which means that preferably ε is a value in the range from 0 to 2×dA, more preferably a value in the range from 0.5×dA to 1.5×dA or from 0.8×dA to 1.2×dA.

[0383] In an embodiment, the values ​​of dA and dB may be values ​​in the range from 0.5 mm to 1.5 mm, for example equal to about 1.0 mm; and the values ​​of L1, L2, L3 (L1=L2=L3) may be values ​​in the range from 5.0 mm to 15.0 mm, for example equal to about 8.7 mm, or equal to about 13.7 mm; and the diameter of the shaft may be a value in the range from 10 mm to 30 mm, or a value in the range from 15 mm to 25 mm, for example equal to about 17 mm.

[0384] Fig.22A Shows something like Fig. 20 or Fig.21 A side view of a torque sensor system of a torque sensor system, and Fig. 22B Shows something like Fig. 20 or Fig.212200a, 2200b are mounted near an axis 2273 and are spaced apart by an angle of at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95°, or at least 120°, or at least 150° (e.g., approximately 180°) in a circumferential direction. As can be seen, the first sensor S1 and the second sensor S2 are located in the space between the first virtual plane Ω1 and the second virtual plane Ω2, the first virtual plane Ω1 is oriented perpendicular to the axial direction of the axis (e.g., X) and intersects the axis at a first axial position between the first magnetized portion 2271a and the second magnetized portion 2271b, and the second virtual plane Ω2 is oriented perpendicular to the axial direction of the axis and intersects the axis at a second axial position between the second magnetized portion 2271b and the third magnetized portion 2271c.

[0385] Reference Fig. 22B When the shaft is mounted in the housing between the two sensor devices 2200a, 2200b, ideally the first gap c1 and the second gap c2 will be substantially equal to each other, but in practice there may be some radial positional offset of the shaft, which may result in c1 increasing and c2 decreasing, or c1 decreasing and c2 increasing. The effect of such radial offset can be reduced by combining the difference signals obtained from the two magnetic sensor devices. When using a Fig.21 When the sensor device explained in is used, the system is highly robust to both axial and radial misalignment.

[0386] This effect can also be obtained by combining signals obtained from three magnetic sensor devices (not shown) that are circumferentially spaced by at least 30°, or at least 45°, or at least 60°, or at least 70°, or at least 85°, or at least 95°, for example, circumferentially spaced by multiples of about 120°±15°. Note that the angular offset between the sensor devices need not be constant. For example, the angular offset between the first and second devices can be equal to 90°, and the angular offset between the second and third devices can be equal to 90°, and the angular offset between the first and third devices can be equal to 180°.

[0387] The effect can also be obtained by combining signals obtained from four magnetic sensor devices (not shown) that are circumferentially spaced by at least 30°, or at least 45°, or at least 60°, or at least 70°, for example, circumferentially spaced by multiples of about 90°±15°.

[0388] Using multiple magnetic sensor devices spaced circumferentially around an axis (e.g., Fig. 22B The principle of the embodiment of the invention (illustrated in FIG. 1 ) or its variants with three or four sensor devices can also be used with Figures 9 to 19 The torque sensor system shown in FIG. 1 is used in combination. By combining the signals obtained from multiple sensor devices, the influence of the radial play (or radial position offset) of the shaft relative to the housing can be reduced. Or in other words: the robustness against radial offset of the shaft can be improved.

[0389] Fig.23 A flow chart of a method 2300 for determining a torque applied to a shaft is shown. The method comprises the following steps:

[0390] a) In step 2301, a shaft is provided, the shaft comprising at least one axial portion magnetized in a circumferential direction;

[0391] b) In step 2302, a magnetic sensor device integrated in a single package is provided, comprising:

[0392] - a first semiconductor substrate (e.g., a CMOS substrate), the first semiconductor substrate comprising at least a processing circuit;

[0393] - a second semiconductor substrate or semiconductor layer (e.g. Ga-As), which includes the first magnetic sensor (S1), mounted above or below or adjacent to the first substrate;

[0394] - a third semiconductor substrate or semiconductor layer (e.g. Ga-As) comprising a second magnetic sensor (S2) mounted above or below or adjacent to the first substrate at a predefined distance (dx) from the first sensor (S1);

[0395] c) In step 2303, a sensor device is arranged near the shaft;

[0396] d) In step 2304, a first magnetic field component (e.g., Bz1) is measured using a first magnetic sensor (S1), and a second magnetic field component (e.g., Bz2) parallel to the first magnetic field component (e.g., Bz1) is measured using a second magnetic sensor (S2);

[0397] e) in step 2305, determining a pairwise difference (eg, ΔBz) between a first magnetic field component (eg, Bz1) and a second magnetic field component (eg, Bz2);

[0398] f) In step 2306, based on the pairwise differences (eg, as a predefined function of the pairwise differences), output a signal or value indicative of the torque applied to the shaft (eg, as a value proportional to the pairwise differences).

[0399] Step a) may comprise providing a shaft having only one axial portion magnetized in the circumferential direction (e.g. Figures 11 to 15 ), or providing a shaft having two axial portions magnetized in opposite circumferential directions (e.g., as shown in Fig. 9 , Fig.10 , Fig.16 , Fig.17 ), or providing a shaft having two axial portions magnetized in the same circumferential direction (e.g., as shown in Fig.18 , Fig.19 ).

[0400] In the sensor device provided in step b), the first semiconductor substrate is electrically connected to the second semiconductor substrate (e.g., by means of at least one RDL layer or by means of bonding wires) and to the third semiconductor substrate. The magnetic sensor of the sensor device may be a 1D magnetic sensor including, for example, one or more horizontal Hall elements connected in series or in parallel (e.g., in Fig. 9 , Fig.11 , Fig.15 , Fig.18 ), or including one or more vertical Hall elements or magnetoresistive elements (e.g., in Fig.10 , Figure 12 to Figure 14 , Figure 16 to Figure 17 , Fig.19 middle).

[0401] Step c) may include: Figures 9 to 19 As shown in any of the above, the sensor device is arranged relative to the axis. In some cases, this means that the distance dx between the sensor element and the number and / or size of the axial zones and / or the distance between the axial zones needs to satisfy a predefined relationship.

[0402] The sensor device provided in step b) may comprise a non-volatile memory comprising data of a predefined function, such as coefficients of a polynomial function, or a look-up table, or predefined constants, allowing the processing circuit to calculate the torque applied to the shaft.

[0403] Fig.24 A flow chart of a method 2400 for determining a torque applied to a shaft is shown, which can be viewed as Fig.23 The method 2400 is a special case or variation of the method 2300. The method 2400 comprises the following steps:

[0404] a) in step 2401, providing a shaft, the shaft comprising a first axial portion, a second axial portion and a third axial portion magnetized in a first circumferential direction, a second circumferential direction and a third circumferential direction, respectively, the second portion being located between the first portion and the third portion, the third circumferential direction being equal to the first circumferential direction, and the second circumferential direction being opposite to the first circumferential direction and the third circumferential direction;

[0405] b) In step 2402, at least one magnetic sensor device is provided, comprising:

[0406] - a first semiconductor substrate (e.g., a CMOS substrate), the first semiconductor substrate comprising at least a processing circuit;

[0407] - a second semiconductor substrate or semiconductor layer (e.g. Ga-As), comprising a first magnetic sensor (S1), such as at least one horizontal Hall plate;

[0408] - a third semiconductor substrate or semiconductor layer (e.g. Ga-As) comprising a second magnetic sensor (S2), such as at least one horizontal Hall plate, the second sensor being positioned at a predefined distance "dx" from the first sensor (S1);

[0409] c) In step 2403, at least one sensor device is arranged near the shaft, for example, Figures 20 to 22B As shown in any one of ;

[0410] d) in step 2404, measuring a first magnetic field component (e.g., Bz1) using a first magnetic sensor (S1), and measuring a second magnetic field component (e.g., Bz2) parallel to the first magnetic field component (e.g., Bz1) using a second magnetic sensor (S2) of at least one magnetic sensor device;

[0411] e) in step 2405, determining at least one pairwise difference (e.g., ΔBz) between a first magnetic field component (e.g., Bz1) and a second magnetic field component (e.g., Bz2);

[0412] f) In step 2406, based on the at least one pairwise difference (e.g., as a predefined function of the pairwise difference), output a signal or value indicative of the torque applied to the shaft (e.g., as a value proportional to the pairwise difference).

[0413] The shaft may have three axial regions having Figures 20 to 22B The dimensions L1, L2, L3 shown in the figure, the three axial zones are separated by distances dA, dB, and the distance dx between the sensor elements can be as follows Fig.21 Select as explained in .

[0414] Fig.25is shown at a distance from the axis (the axis has an outer diameter D of about 17 mm, as Fig.21 Graph of magnetic field strength measured at a distance "g" of about 1 mm when the magnet is magnetized as described in , where L1 = L2 = L3 is about 8 mm, and dA = dB is about 1 mm.

[0415] The curve indicated by the black circle shows the measurement of the magnetic field strength (e.g., the amplitude of the radial component) for the first shaft made of a maraging steel of grade C300, but the present invention is not limited thereto, and other suitable types of maraging steels may also be used, such as the so-called 18Ni maraging steel with 200 steel grade, or 250 steel grade, or 300 steel grade, or 350 steel grade, also known as maraging C200 steel alloy, maraging C250 steel alloy, maraging C300 steel alloy, or maraging C350 steel alloy. In fact, not only C-type maraging steels but also T-type maraging steels may be used, such as maraging T200 steel alloy, maraging T250 steel alloy, maraging T300 steel alloy, or maraging T350 steel alloy.

[0416] The curve indicated by the black square shows the measurement of the magnetic field strength (e.g. the amplitude of the radial component) for a second shaft made of martensitic steel (more specifically, X20Cr13 grade, AISI 420 type stainless steel), but again, the invention is not limited thereto, and other suitable martensitic steel types may also be used, for example, martensitic stainless steel with 410 steel grade, or 420 steel grade, or 440 steel grade, also referred to as type 410, type 420 or type 440, preferably condition H (i.e. hardened). Preferably, the martensitic stainless steel comprises 12% to 17wt% Cr.

[0417] In a preferred embodiment, the entire shaft or at least the outer portion of the shaft (e.g., a ring surrounding the inner shaft) is made of steel (e.g., maraging steel or martensitic stainless steel) having a coercivity (Hc) of at least 35 Oersted, or at least 40 Oersted, or at least 45 Oersted.

[0418] Fig.26 A 3D perspective view of a shaft having an outer diameter D, and a first end and a second end is shown. In the example shown, both ends have four flat surfaces that together form a substantially square cross-section, optionally with rounded corners. The shaft is preferably made of maraging steel or martensitic stainless steel, such as Fig.25 Described in . Fig.26The shaft of the 1000 further has two axial blind holes with internal threads. Such shafts are ideally suited for electric bicycles, but the invention is not limited to the shape and size of shafts for electric bicycles, as the same principle can also be used for other torque sensor systems, such as other automotive, industrial or robotic applications.

Claims

1. A magnetoelastic torque sensor system, the magnetoelastic torque sensor system comprising: a shaft comprising at least one axial portion magnetized in a circumferential direction; a magnetic sensor device arranged in the vicinity of the shaft and comprising three semiconductor substrates, the three semiconductor substrates comprising at least a first semiconductor substrate (109) comprising a processing circuit, a second semiconductor substrate (106a) comprising a first magnetic sensor (S1), and a third semiconductor substrate (106b) comprising a second magnetic sensor (S2), each magnetic sensor being configured to measure a magnetic field component of a magnetic field generated by the shaft when a torque is applied to the shaft; wherein the first semiconductor substrate (109), the second semiconductor substrate (106a) and the third semiconductor substrate (106b) are incorporated into a single package device having a plurality of terminals electrically connected to the first substrate (109); Therein, the processing circuit is configured to determine pairwise differences between the measured field components and to output a signal indicative of a torque applied to the shaft based on the pairwise differences.

2. The magnetoelastic torque sensor system according to claim 1, in, The magnetic sensor device is configured for measuring or estimating a first temperature of the first sensor (S1) and a second temperature of the second sensor (S2), and for temperature compensating the signals obtained from the first sensor and the second sensor before determining the difference.

3. A magnetoelastic torque sensor system according to any one of the preceding claims, in, The first substrate (109) further comprises a temperature sensor for measuring the temperature of the host substrate, and wherein the processing circuit is configured to perform a temperature correction on the sensor signal based on the measured temperature before determining the difference.

4. A magnetoelastic torque sensor system according to any one of the preceding claims, in, Each of the sensor substrates (106a, 106b) further comprises a temperature sensor for measuring the temperature of the sensor substrate, and Therein, the processing circuit is configured to perform temperature correction on the sensor signal based on the temperature signals before determining the difference.

5. A magnetoelastic torque sensor system according to any one of the preceding claims, in, The first semiconductor substrate (109) mainly comprises silicon; and The second semiconductor substrate (106a) and the third semiconductor substrate (106b) mainly include silicon and / or are separate silicon substrates.

6. The magnetoelastic torque sensor system according to any one of claims 1 to 4, in, The first semiconductor substrate (109) mainly comprises silicon; and The second semiconductor substrate (106a) and the third semiconductor substrate (106b) include compound semiconductor materials selected from the III-V group.

7. A magnetoelastic torque sensor system according to any one of the preceding claims, in, The sensor device is a wafer-level package device; wherein the first semiconductor substrate (109) is positioned between the second semiconductor substrate (106a) and the third semiconductor substrate (106b); And wherein the first semiconductor substrate (109) is electrically connected to the second semiconductor substrate (106a) and to the third semiconductor substrate (106b) by means of at least one redistribution layer (RDL).

8. The magnetoelastic torque sensor system according to any one of claims 1 to 6, in, The magnetic sensor device further comprises a lead frame; wherein the first substrate (709) is positioned on a single side of the lead frame, between the second semiconductor substrate (706a) and the third semiconductor substrate (706b); And wherein the first semiconductor substrate (709) is electrically connected to the second semiconductor substrate (706a) and to the third semiconductor substrate (706b) by means of bonding wires.

9. The magnetoelastic torque sensor system according to any one of claims 1 to 6, in, The magnetic sensor device (600; 600'; 600") further comprises a lead frame; wherein the first semiconductor substrate is mounted to the lead frame, and wherein the second semiconductor substrate and the third semiconductor substrate are arranged on top of or below the first substrate; And wherein the first semiconductor substrate is electrically connected to the second semiconductor substrate and to the third semiconductor substrate by means of bonding wires.

10. The magnetoelastic torque sensor system (1070; 1770) according to any of the preceding claims, in, The shaft comprises at least a first axial portion magnetized in a first circumferential direction, and the shaft optionally further comprises a second axial portion magnetized in a second circumferential direction opposite to the first circumferential direction; and wherein the magnetic sensor device is oriented relative to the axis such that a first axis (X) defined by an imaginary line passing through the first sensor (S1) and the second sensor (S2) is parallel to the axis; and wherein the first sensor (S1) and the second sensor (S2) are configured to measure a first magnetic field component and a second magnetic field component (Bax1, Bax2) oriented parallel to the axis; And wherein the first sensor (S1) is positioned at a first axial position near the middle of the first magnetized axial portion, and wherein, if the second magnetized axial portion is present, the second sensor (S2) is positioned near the middle of the second magnetized axial portion.

11. The magnetoelastic torque sensor system (1370; 1570) according to any one of claims 1 to 9, in, The magnetic sensor device is oriented relative to the axis such that a first axis (X) defined by an imaginary line passing through the first sensor (S1) and the second sensor (S2) is oriented radially with respect to the axis; and wherein the first sensor (S1) and the second sensor (S2) are configured to measure a first magnetic field component and a second magnetic field component (Bax1, Bax2) oriented parallel to the axis; And wherein the first sensor (S1) is positioned at an axial position near the middle of the magnetized axial portion and at a first distance (d1) from the axis, and wherein the second sensor (S2) is positioned at the same axial position as the first sensor (S1) but at a second distance (d2) from the axis, the second distance (d2) being greater than the first axial distance (d1).

12. The magnetoelastic torque sensor system (1170) according to any one of claims 1 to 9, in, The magnetic sensor device is oriented relative to the axis such that a first axis (X) defined by an imaginary line passing through the first sensor (S1) and the second sensor (S2) is parallel to the axis; and wherein the first sensor (S1) and the second sensor (S2) are configured to measure first and second magnetic field components (Br1, Br2) radially oriented about the axis; And wherein the first sensor (S1) is positioned at a first axial position near a first edge (1175) of the magnetized axial portion (1171), and wherein the second sensor (S2) is positioned at a second axial position near a second edge (1176) of the magnetized axial portion (1171).

13. The magnetoelastic torque sensor system (1270; 1470) according to any one of claims 1 to 9, in, The magnetic sensor device is oriented relative to the axis such that a first axis (X) defined by an imaginary line passing through the first sensor (S1) and the second sensor (S2) is oriented radially with respect to the axis; and wherein the first sensor (S1) and the second sensor (S2) are configured to measure first and second magnetic field components (Br1, Br2) radially oriented about the axis; And wherein the first sensor and the second sensor (S1, S2) are oriented at an axial position near a first edge (1275; 1475) of the magnetized axial portion (1271; 1471).

14. The magnetoelastic torque sensor system (970; 1670) according to any one of claims 1 to 9, in, The shaft comprises at least a first axial portion (971; 1671) magnetized in a first circumferential direction, and the shaft optionally further comprises a second axial portion (972; 1672) magnetized in a second circumferential direction opposite to the first circumferential direction; and wherein the magnetic sensor device is oriented relative to the axis such that a first axis (X) defined by an imaginary line passing through the first sensor (S1) and the second sensor (S2) is parallel to the axis; and wherein the first sensor (S1) and the second sensor (S2) are configured to measure first and second magnetic field components (Br1, Br2) radially oriented about the axis; And wherein the first sensor (S1) is positioned at a first axial position near an edge (975; 1675) of the first magnetized axial portion, and wherein, if the second magnetized axial portion is present, the second sensor (S2) is positioned near an edge (977; 1677) of the second magnetized axial portion.

15. The magnetoelastic torque sensor system (1870; 1970) according to any one of claims 1 to 9, in, The shaft comprises a first axial portion (1871; 1971) magnetized in a first circumferential direction, and a second axial portion (1872; 1972) also magnetized in the first circumferential direction; and wherein the magnetic sensor device is oriented relative to the axis such that a first axis (X) defined by an imaginary line passing through the first sensor (S1) and the second sensor (S2) is parallel to the axis; and wherein the first sensor (S1) and the second sensor (S2) are configured to measure first and second magnetic field components (Br1, Br2) radially oriented about the axis; And wherein the first sensor (S1) and the second sensor (S2) are either both positioned near the inner edge of the corresponding axial portion, or both positioned near the outer edge of the corresponding axial portion.

16. A method (2000) for measuring torque applied to a shaft, the method (2000) comprising the following steps: a) providing (2001) a shaft, said shaft comprising at least one axial portion, said at least one axial portion being magnetized in a circumferential direction; b) providing (2002) a magnetic sensor device in the form of a single packaged device, the magnetic sensor device comprising at least three semiconductor substrates, the at least three semiconductor substrates comprising: a first semiconductor substrate comprising at least a processing circuit, a second semiconductor substrate comprising a first magnetic sensor (S1), and a third semiconductor substrate comprising a second magnetic sensor (S2); c) arranging (2003) the sensor device in the vicinity of the shaft; d) measuring (2004) a first magnetic field component using the first magnetic sensor (S1); and measuring a second magnetic field component using the second magnetic sensor (S2); e) determining pairwise differences between said magnetic field components; f) based on the pairwise differences, outputting (2006) a signal indicative of the torque applied to the shaft.

17. A shaft for a magnetoelastic torque sensor system, The shaft includes at least one axial portion magnetized in a circumferential direction; in, At least one outer portion of the at least one axial portion is made of maraging steel or martensitic stainless steel.

18. The shaft according to claim 17, in, The axial length of the at least one axial zone is a value in the range from 5.0 mm to 15.0 mm; And wherein the outer diameter of the at least one axial zone is a value in the range from 10 mm to 30 mm.

19. A shaft according to claim 17 or claim 18, in, The shaft comprises at least two axial portions magnetized in opposite circumferential directions, or the shaft comprises at least three axial portions magnetized in alternating circumferential directions; And wherein, at least one outer portion of the at least two axial portions or the at least three axial portions is made of maraging steel or of martensitic stainless steel.

20. The shaft according to claim 19, in, The distance (dA, dB) between two adjacent axial zones is a value in the range from 0.5 mm to 1.5 mm; and wherein the axial lengths (L1, L2, L3) of the at least two axial zones or the at least three axial zones are values ​​in the range from 5.0 mm to 15.0 mm; And wherein the outer diameter of the at least two axial zones or the at least three axial zones is a value in the range from 10 mm to 30 mm.

21. A shaft according to any one of claims 17 to 20, in, The shaft is a crank shaft, such as a crank shaft for an electric bicycle; and wherein the shaft has a first end, and a second end opposite the first end; and wherein each of the first end and the second end has at least one flat portion, or at least two flat portions (e.g., opposite to each other), or at least four flat portions (e.g., having a square cross-section); And optionally, each of the first end and the second end has a blind hole, the blind hole extends in the axial direction and has an internal thread or an external thread.

22. An electric bicycle, comprising: A magnetoelastic torque sensor system according to any one of claims 1 to 15; And / or a shaft according to any one of claims 17 to 21.

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