CN106405455A - Magnetic field sensor - Google Patents

Abstract

The present invention relates to magnetic field sensors. An embodiment of a magnetic field sensor comprises a magnetic field sensor arrangement and a magnetic body, eg having a non-convex cross-sectional area relative to a cross-section extending through the magnetic body, the magnetic body having a non-uniform magnetization.

Description

Magnetic field sensor

This application is a continuation-in-part of U.S. Patent Application Serial No. 14/290,780, filed May 29, 2014, entitled "Magnetic Field Sensor," which was filed May 30, 2008, and entitled Divisional of U.S. Patent Application Serial No. 12/130,678 for "Magnetic Field Sensor," which claims priority from German Patent Application No. 102007025000.4, filed May 30, 2007, the entirety of which is hereby incorporated by reference incorporated here.

technical field

Embodiments of the invention relate to a magnetic field sensor comprising a magnet, also referred to as a back bias magnet.

Background technique

In many technical fields, magnetic field sensors are employed, for example, to detect the movement of objects. In some applications, the magnetic field acting on the magnetic field sensor is influenced by the movement of the corresponding object, so that conclusions can be drawn on the movement of the object on the basis of changes in the magnetic field detected by the magnetic field sensor.

Examples are found especially in the field of automotive applications, in which ABS applications (ABS=anti-lock system), for example, use corresponding magnetic field sensors to monitor the movement of the wheels. Other applications in the field of automotive technology include observing or monitoring the movement of crankshafts, camshafts and other shafts in the field of motor vehicles.

Depending on the particular implementation of the respective magnetic field sensor, they comprise a so called back bias magnet which is located in a fixed arrangement with respect to the actual magnetic field sensor element of the magnetic field sensor. In such a magnetic field sensor, the magnetic field detected by the magnetic field sensor itself may thus be at least partly induced by the back-biasing magnet. An object whose motion is eg monitored via a magnetic field sensor may influence or supplement most of the magnetic field by its own magnet or magnetic field components, which will then be detected by the magnetic field sensor.

Back-bias magnets, often implemented as permanent magnets, have different requirements depending on the technology employed in the context of the actual magnetic field sensor element. This may especially take into account the fact that some magnetic field sensor element technologies are sensitive to different magnetic field components, exhibit different responses to the magnetic field and include different magnetic field boundaries specific to the respective type.

Contents of the invention

An embodiment of a magnetic field sensor includes a magnetic field sensor arrangement and a magnetic body comprising a non-convex cross-sectional area relative to a cross-section extending through the magnetic body, the magnetic body comprising a non-uniform magnetization.

Another embodiment of the magnetic field sensor comprises a magnetic field sensor arrangement, a first magnetic body comprising a first magnetization direction and a second magnetic body comprising a second magnetization direction, the first and second magnetization directions being different from each other.

One embodiment of a method of producing a magnetic field sensor includes: providing a magnetic body comprising a non-convex cross-sectional region relative to a cross-sectional plane extending through the magnetic body, the magnetic body having non-uniform magnetization; and the second spatial region exists such that the magnetic flux density caused by the magnetic body in the first spatial region is within the first flux density range with respect to the predetermined spatial direction, and such that the magnetic flux density caused by the magnetic body with respect to the predetermined spatial direction in the second spatial region is Magnetic flux density in the second flux density range; and arranging a magnetic field sensor arrangement comprising first and second magnetic field sensor elements such that the first magnetic field sensor element is arranged in the first spatial region and the second magnetic field sensor element is arranged in the second spatial region Two magnetic field sensor elements.

Another embodiment of a method of producing a magnetic field sensor includes: providing a first magnetic body having a first magnetization direction and a second magnetic body having a second magnetization direction; the first and second magnetization directions being different; with respect to the first magnetic body and A first spatial region and a second spatial region of the second magnetic body exist such that a magnetic flux density within a first flux density range is induced in the first spatial region by the first magnetic body and the second magnetic body with respect to a predetermined spatial direction, and causing a magnetic flux density within a second flux density range caused by the first magnetic body and the second magnetic body with respect to a predetermined spatial direction in the second spatial region; and providing a magnetic field sensor arrangement comprising first and second magnetic field sensor elements , such that the first magnetic field sensor element is arranged in the first spatial region and the second magnetic field sensor element is arranged in the second spatial region.

Description of drawings

Embodiments of the invention will subsequently be described in detail with reference to the accompanying drawings, in which:

Figure 1a shows a cross-sectional view of a first embodiment of a magnetic field sensor;

Figure 1 b shows a cross-sectional view of another embodiment of a magnetic field sensor;

Figure 2 shows a schematic representation of a potential example of the use of an embodiment of a magnetic field sensor;

Figures 3a and 3b show cross-sectional views of further embodiments of magnetic field sensors;

Figure 4 shows the results of a numerical simulation of the resulting magnetic fluid density in the case of an embodiment of a magnetic field sensor and its back-biased magnet;

Figure 5 shows a representation of the x-component of the magnetic flux density in the case of the back-biased magnet shown in Figure 4;

Figures 6a and 6b show cross-sectional views of further embodiments of magnetic field sensors;

Figure 7 shows the results of a numerical simulation of the magnetic flux density for an embodiment of a magnetic field sensor or its back bias magnet;

Figure 8 shows a plot of the x-component of the magnetic flux density for the numerical simulation shown in Figure 7;

Figure 9 shows an enlarged representation of the curve shown in Figure 8;

Figures 10a and 10b show cross-sectional views of further embodiments of magnetic field sensors;

Figure 11 shows the results of a numerical simulation of the magnetic flux density for an embodiment of a magnetic field sensor;

Figures 12a and 12b show various plots of the x-component of the magnetic fluid density for the numerical simulation shown in Figure 11;

Figure 13 shows a cross-sectional representation of another embodiment of a magnetic field sensor;

14A illustrates a cross-sectional view of another non-uniform magnet according to the present disclosure;

Figure 14B illustrates a spatial view of an exemplary shape of another non-uniform magnet;

Figure 14C illustrates a non-uniform back-biased magnet incorporating a die sensor;

Figure 14D illustrates another embodiment of a non-uniform back bias magnet according to the present disclosure;

Figure 15 illustrates the _Bx components for non-uniform and uniform magnetic fields;

Figure 16 illustrates a simulated distribution of magnetization for another non-uniform magnet; and

Figure 17 illustrates the simulated _Bx components for different angles α indicating different non-uniform magnetization levels of another magnet.

detailed description

Figures 1a to 13 show schematic representations of various embodiments of a magnetic field sensor with its magnets or back-biased magnets and the results of numerical simulations in the form of curves or other representations. However, before a more detailed description of potential application scenarios of the magnetic field sensor is given in the context of FIG. 2, the description will initially be given in the context of FIG. .

FIG. 1 a shows a first embodiment of a magnetic field sensor 100 comprising a magnetic body or back bias magnet 110 and a magnetic field sensor arrangement 120 . The magnetic body in FIG. 1 a comprises a recess 130 facing the magnetic field sensor arrangement 120 and having a polygonal cross-section with respect to a cross-section extending through the magnetic body, as depicted in FIG. 1 a.

Here, in the exemplary embodiment shown in FIG. 1 a , the recess 130 has a polygonal cross section with a total of seven vertices 140 - 1 to 140 - 7 . Unlike the cross-sectional shape of the magnetic body 110 shown in FIG. 1 a , in other embodiments of the magnetic field sensor 100 the recesses 130 of the magnetic body 110 may also comprise a number of vertices 140 deviating from seven. For example, in the case of a triangular recess, this recess may also comprise only three vertices 140 with respect to the respective cross-sectional plane extending through the magnetic body 110 . In principle, however, any number of vertices 140 may define a corresponding cross-sectional shape of the recess 130 with respect to the cross-sectional plane.

With respect to the shape and extension of the magnetic body 110 perpendicular to the cross-sectional plane shown in FIG. 1a, the corresponding magnetic body 110 may comprise, for example, same cross-sectional plane. In other words, depending on the particular implementation of the recess 130, the same shape may result with respect to a cross-sectional plane extending through the center point or any other specified point. For example, in this case the set of all potential vertices 140 would form a circular and/or elliptical set of points with respect to a plane perpendicular to the plane shown in FIG. A collection of points of a shape.

In other embodiments of the magnetic field sensor 100 , the magnetic body 110 may exhibit other shapes with respect to the recess 130 in a plane that is not the cross-sectional plane. For example, such a recess 130 may comprise, with respect to a plane perpendicular to the plane shown in FIG. 1 a , a cross-sectional shape deviating therefrom. Thus, it is possible, for example, that the respective recess 130 is implemented in the shape of a groove in the magnetic body 110, so that in this case the respective cross-section through the respective magnetic body 110 has, for example, a rectangular shape, a square shape or any other shape, which is a convex of.

Of course, there are other configurations of the magnetic body 110 of an embodiment of the magnetic field sensor 100, where the corresponding cross-section perpendicular to the plane shown in Fig. 1 a also has a polygonal, elliptical or any other cross-sectional shape.

In addition, other configurations of the magnetic bodies 110 magnetized in a non-uniform manner can naturally also be employed in embodiments of the magnetic field sensor 100 . For example, a magnetic body 110 magnetized in an inhomogeneous manner may also exhibit a non-uniform magnetization with respect to straight connecting line 160 drawn as a dashed line in FIG. Mirror image” cross-sectional shape, as long as the magnetic body 110 is magnetized in a non-uniform manner.

However, in the embodiments presented below, specific reference should be made to non-convex magnetic bodies 110 in order to simplify the description, however, the ensuing description is applicable to substantially all magnetic bodies 110, which are magnetized in a non-uniform manner.

The magnetic body 110 as depicted for example in FIG. 1 a thus comprises a non-convex cross-sectional plane 150 with respect to a cross-sectional plane extending through the magnetic body 110 . In this context, a set of points within a plane (ie, for example also a cross-sectional area such as cross-sectional area 150 ) is exactly at any two points respectively for the corresponding quantity, which is indeed also a direct direct distance between these two points. The connection line is convex when fully extended within the corresponding amount, ie within the cross-sectional area 150 . In other words, a quantity in a plane is convex precisely when all potential straight connecting lines of all potential points of the corresponding quantity extend completely within the quantity.

As explained above, the cross-sectional area 150 of the magnetic body 110 is non-convex because, for example, a straight connecting line 160 (whose endpoints are both located within the cross-sectional area 150 are elements of the corresponding amount) is drawn as a dashed line in FIG. That is to say a corresponding amount of elements, but not completely within the corresponding amount, ie within the cross-sectional area 150 . Instead, the straight connection line 160 intersects the recess 130 . Thus, the cross-sectional area 150 is non-convex, so that it may also be referred to as concave. The terms concave and non-convex may therefore possibly be used synonymously.

The magnetic body 110 of the embodiment of the magnetic field sensor 100 shown in Fig. 1a may eg be made of a permanent magnetic material. Depending on the boundary conditions on which the embodiment of the magnetic field sensor is not to be used, i.e. especially with regard to potential temperature use, cost, useful magnetic field and other parameters, the magnetic body 110 can also be made of, for example, iron, cobalt nickel or other relatively complex compounds and alloys which may include the above mentioned metals as constituents. In principle, corresponding magnetic bodies or back-bias magnets 110 can be produced from ferrite, aluminum-nickel-cobalt (AlNiCo), but also samarium-cobalt (SmCo) or neodymium-iron-boron (NdFeB). Of course, other material combinations or materials are also feasible as application fields for the corresponding magnetic body 110 .

As indicated by arrow 170 in FIG. 1 a , the magnetic body or back-bias magnet 110 has a non-uniform magnetization. The magnetization M of the magnetic body 110 has here been generated in particular to be non-uniform, with various magnetizations occurring at various points, in particular within the cross-sectional area 150, which magnetizations are at least relative to their magnitude or strength and/or their direction. different.

In other words, the magnetization of a magnetic body is inhomogeneous when most of it is not, homogeneous magnetization being understood in the context of this application to mean a magnetization that is constant and unidirectional with respect to its direction and strength. Stated another way, the magnetic body 110 has a non-uniform magnetization as shown by arrow 170 because the magnetization of the magnetic body 110 does not have a constant direction of the magnetization M across the entire magnetic body or across a substantial portion of the entire magnetic body in a vector sense and/or or constant amplitude. In the context of the present application, the entire magnetic body 110 or the main part of the magnetic body 110 is understood to mean a range from 50% to 100%, ie for example 95%, 90%, 80%, 75%, 70% or 60%. The volume fraction of the magnetic body 110 , possibly the corresponding volume fraction, is generated according to the application of the embodiment of the magnetic field sensor and the corresponding field of implementation.

Also, it should be noted here that for many magnets comprising a magnetization that is constant in magnitude and direction throughout the bulk volume, i.e. magnetized in a uniform manner, the resulting magnetic field can be external to the magnet and The interior is non-uniform on both. In other words, the presence of a non-uniform magnetic field on the exterior and/or interior of the magnet need not be an indication that the magnetization is also non-uniform. Uniform magnetizations are particularly attractive in many cases because they can be fabricated in a rather simple and cheap manner.

The magnetic body 110 or the back bias magnet 110 of the embodiment of the magnetic field sensor 100 as shown for example in FIG. 3T) residual magnetic flux density. Depending on the specific implementation and specifications of the embodiment of the magnetic field sensor 110, the magnetic body 100 may thus include a "magnetization" or residual magnetic flux density Brem, which exists due to the magnetization, eg typically 500 mT or 1 T. However, it should be pointed out in this context that the flux density ranges mentioned above are not to be understood in a limiting sense. Rather, they are merely examples of some areas of application as may be used in embodiments of the magnetic field sensor 100 . In principle, other magnetizations can be used depending on various parameters, ie, eg parameters of the individual magnetic field sensor element technology, the dimensions of the corresponding magnetic field sensor and other parameters.

In addition to the magnetic body or back bias magnet 110, the embodiment of the magnetic field sensor 100 shown in FIG. as an optional part. In the embodiment shown in Fig. 1a, the sensor arrangement 120 comprises at least two magnetic field sensor elements 190-1, 190-2 depicted in Fig. 1a. Depending on the technology used, the magnetic field sensor element 190 may be a magnetoresistive sensor element (xMR sensor element), a Hall sensor element, or another sensor element that reacts to magnetic influences, such as a magnetic diode or a magnetic transistor.

With regard to the present invention, it should be pointed out that magnetic field sensor elements may especially be advantageously employed with such sensors or sensor elements exhibiting saturation characteristics, ie eg xMR sensor elements.

In contrast, Hall probes, for example, hardly saturate. However, since the amplifier connected downstream from the Hall probe exhibits saturation characteristics (as the amplifier becomes saturated outside its dynamic range), it may also be advantageous to use the magnetic bodies described here with the Hall probe.

Magnetoresistive sensor elements include, inter alia, AMR sensor elements (AMR = Anisotropic Magneto-Resistance), GMR sensor elements (GMR = Giant Magneto-Resistance), CMR sensor elements (CMR = Colossal Magneto-Resistance), EMR sensor elements (EMR = Extraordinary Magnetic resistance), a TMR sensor element (TMR = tunneling magnetoresistance), or a spin valve sensor element. Hall sensors can be horizontal or vertical Hall sensors.

Depending on the particular embodiment, the magnetic field sensor arrangement 120 may comprise further components, such as evaluation circuits, sensor circuits or corresponding encapsulation materials for protecting the individual magnetic field sensor elements 190 .

In some embodiments of the magnetic field sensor 100, as shown in FIG. _1a , for example, the magnetization M _is shown in FIG. Symmetry line 195 has the following symmetry conditions:

M _x (x) = -M _x (-x)

M _y (x) = M _y (x) (1).

This means that the _x -component Mx of the magnetization has odd symmetry about the line of symmetry 195 at x=0, and the _y -component My has even symmetry about the x-coordinate and the line of symmetry 195. More generally, magnetization M has an odd symmetric relationship with respect to an associated magnet 110 with respect to a component, and an even symmetric relationship with respect to another component in some embodiments of a magnetic field sensor. More specifically, in some embodiments of the magnetic field sensor, the magnetization M of the magnetic body 110 has an even symmetric relationship with respect to a vector component and an odd symmetric relationship with respect to a vector component perpendicular to the vector component.

Before further embodiments of magnetic field sensors will be described and explained in connection with FIGS. 1 b to 13 , it should be noted that objects, structures and components having the same or similar functional properties and features are designated by the same reference numerals. Descriptions of objects, structures and components having similar or identical functional properties and characteristics are interchangeable unless expressly stated otherwise. In addition, in the further course of the application, general reference signs shall be used for objects, structures and objects that appear several times in the same or similar manner in one embodiment or in similar manners in different drawings, embodiments. Parts, unless the characteristics or properties of a very specific object, structure or part are explained and discussed. The utilization of overview reference signs thus enables a more concise and clear description of embodiments of the invention.

Fig. 1 b shows another embodiment of a magnetic field sensor 100 which differs only slightly from the embodiment shown in Fig. 1 a. The embodiment of the magnetic field sensor 100 shown in FIG. 1 b again comprises a magnetic body 110 , the magnetization M of which is again indicated by arrow 170 . In the embodiment depicted in FIG. 1 b , the magnetization M is also non-uniform over a large portion of the magnetic body, as indicated by the trajectory of arrow 170 . More specifically, the magnetization M of the magnetic body 110 again has the symmetry condition described in conjunction with equation (1).

Unlike the embodiment depicted in FIG. 1 a , the magnetic body 110 of the embodiment of the magnetic field sensor 100 shown in FIG. 1 b has a different trajectory with respect to the upper edge. More specifically, in the embodiment depicted in Figure Ia, the upper edge of the magnet 110 is bounded by a straight line, whereas in the magnet 110 in Figure Ib, the magnet extends upwardly beyond the area indicated in Figure Ib. However, despite its magnetic body depicted in FIG. 1 b, the cross-sectional area 150 is non-convex with respect to the reproduced cross-sectional plane in FIG. 130 intersects and thus lies within cross-sectional area 150 . In other words, regardless of the upper or outer shape, the cross-sectional region 150 of the magnetic body 110 is non-convex, regardless of the particular shape of the outer, upper or lateral bounding regions of the magnetic body 110 .

Additionally, the embodiment depicted in FIG. 1 b differs with respect to recess 130 . While in the embodiment shown in FIG. 1 a the recess has a polygonal cross-section, in the embodiment shown in FIG. 1 b the cross-section of the recess shown there is elliptical.

Apart from this, the exemplary embodiment of magnetic field sensor 100 shown in FIGS. 1 a and 1 b differs little. In the embodiment shown in FIG. 1 b, the cross-section of the magnetic body 110 may comprise a different shape, a similar shape or even the same shape with respect to a plane perpendicular to the cross-sectional plane shown in FIG. 1 b.

In both embodiments shown in FIGS. 1 a and 1 b , the magnetic field sensor arrangement 120 is arranged relative to the magnetic body 110 such that the arrangement 120 is also ideally positioned such that it also has a center of gravity point of the magnetic field sensor arrangement 120 on the symmetry line 195 or center point. Furthermore, the magnetic field sensor arrangement 120 is ideally aligned with respect to the line of symmetry 195 such that the connecting line not shown in FIGS. 1 a and 1 b of the two magnetic field sensor elements 190 shown there intersects the line of symmetry 195 at right angles. In other words, the magnetic field sensor arrangement 120 is ideally arranged such that it replicates or adopts the above-described symmetry of the magnetization M of the magnetic body 110 . Of course, in the case of a practical implementation of a corresponding embodiment of the magnetic field sensor 100 , deviations may arise with respect to offsets in the x-direction and/or in the y-direction and with respect to rotation about any of these axes or any axis perpendicular thereto.

As will be explained further on in this application, this precisely the non-uniform magnetization M of the magnetic body 110 described above in some embodiments of the magnetic field sensor combined with its cross-sectional shape while taking into account the techniques used by the magnetic field sensor element 190 can An improvement of increased positioning tolerances of the magnetic field sensor arrangement 120 with respect to the magnetic body 110 is achieved. In other words, in some embodiments of the magnetic field sensor 100 , greater tolerances can be achieved with respect to the precise layout of the magnetic field sensor arrangement 120 without necessarily accepting concerns about measurement accuracy, functionality, or other parameters, which may possibly be caused by the magnetic field sensor element 190 being unfavorably positioned with respect to the magnetic body 110 .

Especially in the case of the magnetoresistive magnetic field sensor element 190 it may be advantageous in some embodiments of the magnetic field sensor 100 to include the magnetic body 110 as in the framework of the embodiment. As will be explained below, in some embodiments overloading of the corresponding magnetoresistive sensor element 190 may possibly be suppressed and/or positioning tolerances of the corresponding sensor element may possibly be increased without or hardly any negative consequences As expected for actual measurement operations.

FIG. 2 illustrates a typical field of use of an embodiment of magnetic field sensor 100 in connection with determining the rate of rotation or rotational speed of a shaft. More specifically, FIG. 2 shows an embodiment of a magnetic field sensor 100 comprising a protective housing included in the magnetic field sensor 100 in addition to a magnetic body 110 which may be implemented as a permanent magnet and a magnetic field sensor arrangement 120 . As already explained above, the magnetic field sensor arrangement 120 additionally comprises two magnetic field sensor elements 190 , which may be magnetoresistive, magnetosensitive sensor elements, for example. As explained above, the magnetic body 110 has been drawn in FIG. 2 in a simplified manner without representing a cross-section with respect to the cross-sectional plane depicted in FIG. 2 and the features explained above with respect to the magnetized magnetic body. Features are not merely reproduced in Figure 2 for simplicity of presentation.

At a distance from the plane of the magnetic field sensor element 190, a distance marked by arrow 200 in FIG. A toothed wheel, which is sometimes called a permeable generator wheel. Other generator objects 210 include drill wheels, magnet wheels, or other circular or elliptical objects suitable considering their choice of material and/or their topology to affect the magnetic field, which is controlled by the magnetic body when the motion of the generator object 210 occurs. 110 generates, and possibly in the case of a magnet wheel, its own magnetic flux density.

Depending on the particular implementation and application scenario, embodiments of the magnetic field sensor 100 may also be employed in conjunction with other generator objects 210 . For example, corresponding embodiments may be employed as generator objects 210 in conjunction with magnet rods, drill rods or racks, for example to detect linear motion or to render it detectable. In many cases, the generator object 210 comprises a periodic structure with regard to magnetization, topology or other features, such that in the event of a motion of the generator object 210 , a periodic change of the magnetic field, in particular of the magnetic body 110 , is induced. The respective generator objects 210 are often implemented as part of or connected to the respective moving parts.

In the case of a toothed wheel as generator object 210 , as shown in FIG. 2 , it may eg be coupled to a shaft (ie a crankshaft or a camshaft) or be coupled to. If the generator object 210 is moved, ie rotated in the case of the toothed wheel depicted in FIG. 2 , as indicated by arrow 220 , this causes a change in the magnetic field which can be detected by the magnetic field sensor 100 .

Depending on the goals envisaged in the field in which the embodiment of the magnetic field sensor 100 is applied, the movement of the wheel may thus be detected eg by means of a magnetic sensor, as may eg be desired in the context of an ABS system. Other embodiments of the magnetic field sensor 100 can be employed, for example, in the field of engine control and monitoring, for example as a crankshaft sensor or a camshaft sensor. In this context the toothed wheel 210 is used especially in combination with a small permanent magnet as the actual sensor or magnetic body 110 on the rear side of the magnetic field sensor arrangement 120 . Moving or rotating the wheel then leads to a sinusoidal magnetic field in the region of the magnetic field element 190 , the components of which are evaluated at chip or substrate level in the case of magnetoresistive sensors (xMR sensors). At the same time, the direction of the rotational movement of the wheel can also possibly be evaluated and detected by another sensor or by means of other technical measurements.

In many applications, a small permanent magnet is therefore mounted as a magnet 110 on a magnetic field sensor arrangement 120 so that both can be arranged in front of a toothed wheel-shaped permeable disc, as schematically shown in FIG. 2 depicted. As the disc rotates, the teeth of the toothed wheel 210 pass through the plane of the magnetic field sensor element 190 at the distance of the magnetic air gap and thus generate small field changes that can be detected by embodiments of the magnetic field sensor 100 and include Angular position and rotational speed information. In many cases, the waveform of the magnetic field change is almost sinusoidal, and its amplitude decreases sharply according to the increasing (magnetic) air gap.

In the case of a toothed wheel as generator object 210, as depicted in FIG. times) roughly exponentially decreases. In this context, the so-called pitch is defined as the quotient of the semi-circumference of the toothed wheel divided by the number of teeth, if distributed equidistantly across the circumference of the toothed wheel. Thus, the pitch represents the half period of a toothed wheel. For this reason, it may be desirable, in some embodiments of the magnetic field sensor 100 and in various fields of application of the magnetic field sensor, to operate the embodiment as close as possible to the generator object 190 in order to bypass and prevent, for example, a magnetic air gap greater than the approximate width of the tooth. An increase in the magnetic air gap from about one tooth width to about 150% of the tooth width may, for example, reduce the magnetic field amplitude by less than 1/5 depending on the particular circumstances. For example, the amplitude depends on exp(-2Pi*z/lamda), lamda is the magnetic period, ie lamda/2 is the width of the tooth or the width of the gap between two teeth. If z = lamda/2 is increased to z = 1.5*lamda/2, the magnitude will thus change by a factor of exp(-Pi)/exp(-Pi*1.5) = 4.8.

In the case of magnetoresistive sensor elements, eg GMR sensor elements 190 , it may happen that the magnetic field components in the plane of the respective magnet arrangement with respect to the substrate or chip overload the individual GMR sensor elements 190 . In this case, it may happen that the magnetic field sensor element(s) 190 involved will not provide any measurement signal, or a barely usable measurement signal.

Thus, even if e.g. the toothed wheel 210 is positioned symmetrically to the chip of the magnetic field sensor arrangement 120, i.e. if e.g. the tooth center or gap center of the toothed wheel 210 is directly at the (xx=0) position also plotted in FIG. 2 , then a divergence of the flux lines of the magnet may occur, according to which an unacceptably large Bx component will act on the two (magnetoresistive) magnetic field sensor elements 190 shown in FIG. 2 . As already explained in connection with FIGS. 1a and 1b, the (x=0) position is here defined by the line of symmetry 195, which combines FIG. Location dependent.

In this case, the two magnetoresistive sensor elements 190 are driven into saturation and can no longer emit any (usable) signal. In some applications where embodiments of the magnetic field sensor 100 are employed, the common remanence of the magnets used or the back bias magnet 110 is in the range of just above 1 Tesla (T). A typical toothed wheel as generator object 210 comprises approximately 3 mm wide teeth and gaps, the depth of which also corresponds to about 3 mm. Of course, other indicated dimensions of corresponding toothed wheels or other generator objects may occur in other examples of use. Furthermore, corresponding embodiments of the magnetic field sensor 100 are not limited to these values. It should be noted that in the context of the present invention a large magnetic field at the xMR element can be achieved eg using a large magnet or using a large remanence or using a small demagnetization factor.

Depending on the particular application, the magnetoresistive sensor element 190 is typically arranged within about 1 mm in front of the magnet or magnet 110, and the toothed wheel itself is arranged about 1 to 4 mm in front of the magnetoresistive sensor element 190, Make the magnetic air gap also within this range. In some applications and thus in some embodiments of the magnetic field sensor 100, the magnet or magnetic body 110 has a cross-section of 5 mm in the x-direction and 6 mm in the y-direction, the magnetoresistive sensor elements 190 at the chip are spaced apart by approximately 2.5 mm. In this case, it may happen that the Bx component of the magnetic field strength on the right-hand one of the two field elements 190 ranges from about 95 to 117 mT, with different values resulting from the (magnetic) air gap. Thus, in the case of a symmetrical layout, a Bx component ranging from -95 to -117 mT acts on the sensor element 190 of the left hand. Depending on the specific implementation of the magnetic field sensor element 190 , especially in the case of a GMR magnetic field sensor element, such sensor elements often have a linear drive range of up to +/−15 mT. If such a GMR sensor element 190 is highly overdriven by a magnet, it will no longer function in a useful way and will no longer be able to provide a useful measurement signal.

With other GMR sensor elements 190, it may happen that they have become saturated at magnetic flux densities of about 10 mT. Therefore, if there is a magnetic field component or a magnetic flux density component greater than 100 mT at the location of the GMR sensor element 190, the latter will be driven into saturation so that the small overlapping alternating magnetic field as can be caused by the generator object 210 is no longer detectable. It may therefore be useful in this case to reduce the magnetic flux density described above by 1/15.

If, for example, a modulation between 12 mT and 14 mT is only caused by the teeth at a saturation field strength of about 10 mT of the GMR sensor element, the corresponding GMR sensor element may in many cases no longer provide a usable output signal, so that the overall sensor It may no longer be possible to detect the rotation of the generator object 210 .

As already explained above, the above numbers indicate special service illustrations and are not to be understood in a limiting sense. Embodiments of the magnetic field sensor 100 may be employed within a very wide range of magnets or magnetic bodies 100 and within a very wide range of different magnetic field sensor elements 190 . Furthermore, embodiments may be combined with many different generator objects 210 in order to form a speed sensor eg or other magnetic based sensors in case of a respective application scenario.

3 a and 3 b show two further exemplary embodiments of a magnetic field sensor 100 . More specifically, both embodiments are depicted together with a generator object 210, possibly a rack or toothed wheel, for example, which is depicted without any curvature in Figures 3a and 3b for simplicity of representation .

The embodiments of the magnetic field sensors 100 depicted in FIGS. 3a and 3b thus each comprise a magnetic body 110 which, with respect to the cross-sectional plane shown in FIGS. 3a and 3b , again comprises a non-convex cross-section with a recess 130 configured to In the embodiment shown in Figures 3a and 3b it is circular. Of course, it can be pointed out in this context that a specified circle or ellipse can also be applied to a corresponding sector or part of a corresponding geometric figure, ie a circle or ellipse.

In the embodiment of the magnetic field sensor 100 depicted in Figures 3a and 3b, the magnet 110 or both back bias magnets 110 again have a non-uniform magnetization, as depicted by arrow 170 in both figures. Depending on the specific implementation of the embodiments, here, in addition to a chip or substrate 180 and a (magneto-resistive) magnetic field sensor element 190, i.e. for example a GMR magnetic field sensor element, the magnetic field sensor arrangement 120 may also possibly include a package also called shell.

In the embodiment depicted in FIGS. 3 a and 3 b , the magnet or magnet 110 is configured as part of a ring and is substantially radially magnetized, as indicated by arrow 170 . More specifically, the magnetic body 110 here has a ring shape, but in other embodiments of the magnetic field sensor 100 it may also have other shapes, such as a flat or upright elliptical shape. As already explained in the context of FIG. 1 b , it is possible to meet the needs of the magnetic body 110 to include an indentation so that the magnetization of the magnetic body 110 described above can be performed. Basically, any desired outer limit curve can thus be provided in principle. As previously explained, in some embodiments of the magnetic field sensor 100, the indentation may be circular, elliptical, or polygonal. In other words, in different embodiments of the magnetic field sensor, the magnetic body may have a non-convex cross-section or a non-convex cross-sectional area in relation to the cross-sectional plane.

Thus, Fig. 3a shows an embodiment in which the magnetic body 110 extends within 180° and is configured as an annulus. In contrast, in the embodiment depicted in Figure 3b, the magnetic body 110, depicted as an annulus, extends over less than 180°. Depending on the particular implementation, the magnet 110 may also extend over more than 180°.

The sensor IC (IC=Integrated Circuit) or magnetic field sensor arrangement 120 can be moved or shifted both "into the magnet" and to the area of the recess 130, as depicted in Fig. 3a. In the case of a relatively small magnet 110 or even in the case of limited design space, the magnet 110 can also be placed on the back of the sensor IC, where depending on the specific implementation of the embodiment of the magnetic field sensor 100, the IC 120 The front side and the bottom side can also be used equally well in many cases with regard to the described fastening.

However, in many cases of application it may be advisable to move the GMR sensor element 190 as close as possible to the toothed wheel or generator object 210 so that it may be advisable in such cases that the magnet 110 Mounted on this side of the chip 120 that does not contain components (eg, magnetic field sensor element 190 ). Therefore, in this case it may be advisable to fix the magnetic field sensor arrangement 120 to the magnetic body 110 so that it is rotated by 180° in the relation here compared to the representation of FIGS. way to fix it to the magnetic body depicted in Figures 3a and 3b. The magnetic field sensor elements 190 may thus be positioned such that they are rotated by 180° relative to the substrate 180 and the generator object 210 .

Depending on the specific implementation, typical dimensions may thus comprise an outer diameter of about 9 mm and an inner diameter of about 5 mm relative to the shape of the magnetic body 110 in the case of the embodiment shown in FIGS. 3 a and 3 b . Depending on the particular implementation of the example, the strength of the residual magnetization may again be higher than about 500 mT or higher than about 1 mT.

In some embodiments, the spacing between two sensor elements 190 is approximately the size of a tooth or tooth gap of the generator object 210 . In some embodiments or in some applications this may be eg 2.5 mm for the distance between the two outer sensor elements shown in Figures 3a and 3b. Depending on the specific implementation, a central sensor element may be employed eg for detecting orientation, it being possible to arrange the central sensor element centrally between the left-hand and right-hand sensor elements. However, in some application areas other distances between sensor elements 190 are useful. Other distances can also be used, eg 1.7 mm.

In many cases, the surface of chip 180 is arranged in front of magnet 110 at a distance ranging from about 0.5 mm to about 2 mm, with a distance of about 0.7 mm often representing a useful compromise because, on the one hand, magnet 110 should be positioned as As close as possible to the chip 180, and thus the magnet wheel 210, and on the other hand, the thickness of the mounted components (package bottom, leadframe thickness, die attach thickness and silicon thickness) are often in the range of about 0.7 mm. The distance of the chip 180 from the generator object 210 (also referred to as the air gap) may amount to tens of millimeters as a minimum, but as a maximum in some areas of application should not exceed the width of approximately four teeth or four tooth gaps , since the magnetic field signal amplitude will decrease exponentially with a larger air gap.

FIG. 4 shows the results of a numerical simulation of the magnetic field strength curve of the magnetic field lines produced as in the case of the magnetic body 110 as described in the embodiment discussed there in the context of FIG. 3 a. Calculating the magnetic field as has given rise to a magnetic field curve such as that shown in FIG. 4 is in many cases not at all complicated, and essentially boils down to solving four Maxwell's differential equations. Simplified forms do exist for special cases, which may possibly be solved in closed form, but are particularly useful for calculating magnetic fields, magnetic flux densities and other curves and properties discussed in the context of this application, which can be based, for example, on binary Numerical simulations performed with 3D or 3D simulations are generally indispensable. Corresponding simulations and calculations can be performed, for example, based on the following equations:

Also taking into account the corresponding boundary conditions, B is the magnetic induction or magnetic flux density as a vector quantity, μ0 specifies the magnetic permeability of the vacuum, red M specifies the rotation of the (vector) magnetization, degreeAr specifies the gradient of the position coordinates with respect to the starting point A, and r is The distance between the start point and the source point. The integration is performed across the entire space, ie not only within the material of the magnetic body 110 but also across its surface, indicated by the "integration boundary" V in equation (2).

In addition to the magnetic body 110 , Fig. 4 also schematically depicts the generator object 210 shown in Figs. 3a and 3b. In addition to a large number of field lines 230, the corresponding magnetic flux densities between a maximum of 0.2 T and 0.5 T are additionally plotted in FIG. 4 for some regions. Here, the arrow 240 in the inner part of the representation in FIG. 4 marks the reduction of the magnetic field strength as depicted by the arrow 250 in the region of the legend.

FIG. 4 thus shows a cross-section of a magnetic body in the form of a ring extending in 180° and magnetized in the radial direction, as already described in connection with FIG. 3 a . The toothed wheel as generator object 210 is here positioned symmetrically to the magnet 110 . At this location, the Bx component of the magnetic flux density at the location of the magnetic field sensor element 190 (not shown in FIG. 4 ) should ideally be as close to zero as possible, but at least within the linear control range of the GMR sensor element, i.e. For example between approximately -15mT and +15mT.

Regarding the magnetic body 110 , the results of the numerical simulations (shown in FIG. 4 ) are based on a magnetic body 110 remanence 1 T that extends uniformly across the entire magnetic body 110 in magnitude. However, an inhomogeneous direction of the magnetization due to its radial nature is thereby exempted.

Additionally, Fig. 4 has a horizontal line 260 drawn between the end faces of the magnet (in the region of line 260), the magnetic field strength Bx has been evaluated from the x-coordinate in the context of the curve represented in Fig. 5 below.

FIG. 5 depicts a total of seven curves 270 - 1 to 270 - 11 reproducing the magnetic flux density Bx in Tesla (T) for the line 260 represented in FIG. 4 . Curve 270 here corresponds in ascending order to the y-positions it indicates after the hyphen in the context of the reference designation (y=-0.5 mm, -0.4 mm, -0,3 mm, -0.2 mm, -0.1 mm, 0 mm , +0.1 mm, +0.2mm, +0.3 mm, +0.4 mm, +0.5 mm).

Curve 270 shows that due to the symmetry of the arrangement, the x-component of the magnetic flux density Bx almost disappears for the x-coordinate x for the case of y=0 (curve 270-6), and would therefore represent a substantially ideal position for the GMR sensor element. If for example the magnetic field sensor elements 190 are positioned such that they are distributed symmetrically around x = 0 at a distance of 1.25 mm, i.e. at x position (x = +/- 1.25 mm), then the range is from y = -0.1 mm to y = A y-position of +0.1 mm is quite suitable to ensure that the x-component of the magnetic field strength is less than 20 mT in magnitude ( < 20 mT), as shown by curves 270-5, 270-6, 270-7 for y-positions of y=0.1 mm, 0 mm, +0.1 mm. Curve 270 substantially includes mirror symmetry about the point (x, Bx) = (0m, 0T). A reduction in the x-component of the magnetic flux density Bx may thus be achieved by employing embodiments of the magnetic field sensor 100 , sometimes potentially by an amount as high as an order of magnitude, compared to a simple cubic magnet with continuously uniform magnetization.

Figures 6a and 6b show a further embodiment of a magnetic field sensor 100 which is similar to the embodiment of Figures 3a and 3b but differs from the embodiment of Figures 3a and 3b in that the magnetic body 110 is magnetized in an azimuthal manner, as Indicated by arrow 170 . With this possibility of embodiment of the magnetic field sensor 100 , as depicted for example in FIG. 6 a , the magnetic body 110 may comprise a circular cross-section extending within 180°. Likewise, as depicted in Figure 6b, it may comprise a cross-section extending in less than 180°. The magnet 110 of the embodiment shown in Fig. 6b can thus be regarded as "cut in radial direction", other shapes of the magnetic body 110 are of course also possible. For example, magnetic bodies 110 are also conceivable in which the end faces are cut off, for example in the x-direction or in the y-direction. As already explained above in the context of FIGS. 1 a , 1 b , 3 a and 3 b , the outer shape of the magnetic body is less decisive in this context. Therefore, other directions inclined to the above-mentioned directions are also possible as the “cross-sectional direction” of the magnetic body 110 .

Apart from the magnetization M as depicted by the arrow 170 in FIGS. 6a and 6b, the embodiments of the magnetic field sensor 100 shown in the figures differ little, or not at all, in respect of further components from those in FIGS. 3a and 3b Example shown. For this reason, reference should be made to their corresponding descriptions, especially with regard to further components.

The magnetization of the magnetic body 110 as depicted in Figures 6a and 6b thus obeys the following symmetry conditions with respect to the x-component Mx( _x ) and the component _My (x):

M _x (x) = M _x (-x)

M _y (x) = -M _y (-x) (3) .

This means that in this case the x-component of the magnetization has even symmetry about the line of symmetry 195 (x=0), while the y-component of the magnetization in this case satisfies an odd symmetry about x. In this case, it may also be stated in some embodiments of the magnetic field sensor 100 that one of the two magnetization components M _x and My _y satisfies an odd symmetric relation about x and the other satisfies an even symmetric relation about the x coordinate.

7 shows a representation based on the results of numerical simulations of a magnetic body 110 comprising an extension greater than 180° and being magnetized in the azimuthal direction, the magnitude of the magnetization being set constant across the volume of the magnetic body 110 . In other words, the large simulation results shown in FIG. 7 are based on an embodiment of a magnetic field sensor comprising a magnetic body 110 that is magnetized with a constant amplitude in the azimuthal direction, so that the magnetization is again non-uniform due to its changing direction . Here again, FIG. 7 shows a plurality of field lines 230 and arrow 240 in the inner portion of the representation corresponding to the direction of decreasing magnetic flux density along the range from 0.5 T to 0.2 T (as also indicated by arrow 250 ). In addition, a different line 260 is drawn again in FIG. 7 , which correlates to the curve 270 reproduced in FIGS. 8 and 9 . In other words, within the context of the following FIGS. 8 and 9 , the suitability of the different lines 260 for potential positions of the magnetic field sensor elements 190 is checked.

FIG. 8 shows curves 270 - 1 to 270 - 8 of the x-component of the magnetic flux density Bx according to the x-coordinate for different y-coordinates. More specifically, the curve 270-1 here corresponds to the y-coordinate of y=-0.80 mm, which in each case decreases by 0.1 mm as the number of the corresponding curve increases, the curves are in the context of the reference marks in the hyphen was reproduced afterwards. Thus, curve 270-2 corresponds to a y-coordinate of y=−0.9 mm, and, for example, curve 270-8 corresponds to a y-coordinate of y=−1.50 mm. Here, FIG. 8 initially shows the corresponding curve 270 on a coarse scale in the range from x=−2 mm to x=+2 mm, while FIG. 9 shows a representation from about x=1.0 mm to x=1.85 mm range enlargement.

Therefore, FIG. 8 initially shows that almost independently of the y parameter chosen in each case, in the range between from about x=1.3 mm and x=1.4 mm, all curves 270 have a range from about +/-( 20 mT–40 mT) x component of the magnetic flux density Bx. At smaller distances from the magnet or magnetic body 110, i.e. for higher y values, the curve 270 runs through the B _x = 0 line in the region around x = +/- 1.4 mm, so that this can for example represent A rather suitable location for the sensor element 190 , ie the GMR sensor element 190 .

Thus, in FIG. 9 the range of the curves depicted in FIG. 8 is represented in an exaggerated manner in the range around x=1.4 mm. For example, FIG. 9 shows that the curves 270-2, 270-3 and 270-4 corresponding in particular to the y parameter (y=-0.9 mm, -1.0 mm and -1.1 mm) are in the range around x=1.4 mm with The "Bx=0" lines intersect, as shown by the detailed diagram in FIG. 9 .

Before further embodiments of the magnetic field sensor 100 will be described in the context of FIGS. 10 a and 10 b , a short overview of the method by which the non-uniform magnetization discussed in the preceding figures can be achieved will be given. In the case of magnetic bodies 110 comprising radial or quasi-radial magnetization as shown for example in FIGS. In the recess 180 of the magnetic body, the counterpart seamlessly adjoins the suitably shaped surface of the magnetic body 110 . Furthermore, suitably shaped iron parts can be placed into the outer surface from the outside, so that the other magnetic body 110 is covered from the outside and the inside by the corresponding iron parts. Subsequently, the two iron parts can be interconnected by a clamp, which can have almost any shape desired. A winding may be wound around the fixture, the winding having an electrical current applied to it in order to generate the magnetization.

In the case of a magnetic body with azimuthal magnetization, a circular conductor can be placed inside the magnet, ie in the recess 130 of the magnetic body 110, and the circular conductor can be fixed externally to the magnetic body tightly, ideally seamlessly 110. If the current flowing in the inner metallic conductor is sent out of the plane of the drawing drawn in Figures 6a and 6b, and correspondingly, if the corresponding current in the outer conductor is sent into the plane of the drawing, the corresponding magnetization in the magnet 110 will Align in the azimuth direction in a counterclockwise manner.

Figures 10a and 10b show a further embodiment of a magnetic field sensor 300 which differs from the above shown embodiment of the corresponding magnetic field sensor 100 in that the embodiment shown here comprises a first magnetic body 310 and a second magnetic body 320, The first magnetic body 310 comprises a first magnetization direction characterized by arrow 330 in Figs. 10a and 10b, respectively. Likewise, the second magnetic body 320 has magnetization directions plotted by arrows 340 in FIGS. 10 a and 10 b , respectively. The two magnetization directions of the two magnetic bodies 310, 320 are different from each other and form an angle with each other.

Regarding the line of symmetry 195 again corresponding to the x-coordinate of x=0, depending on the specific implementation of the corresponding embodiment of the magnetic field sensor 300 and its specification, the magnetization directions (arrows 330 , 340 ) of the two magnetic bodies 310 , 320 are each related to The line of symmetry 195 forms an angle which is the same in magnitude for the two magnetic bodies 310 , 320 or does not deviate from each other, typically greater than 20°, 10°, 5° or 2°. In other words, the two magnetic bodies 310 , 320 comprise symmetrical magnetizations about the line of symmetry 195 in many embodiments of the magnetic field sensor 300 .

Furthermore, the embodiments of magnetic field sensors 300 depicted in FIGS. 10 a and 10 b again each comprise a magnetic field sensor arrangement 120 having a substrate 180 and one or more magnetic field sensor elements 190 . As already described in connection with the above explained embodiments of the magnetic field sensor 100 , the magnetic field sensor arrangement may comprise a single magnetic field sensor element 190 or a plurality of corresponding magnetic field sensor elements 190 . In the embodiments shown in FIGS. 10 a and 10 b , the magnetic field sensor arrangement 120 comprises in each case two magnetic field sensor elements 190 arranged substantially symmetrically about a line of symmetry 195 , for example by means of the potential magnetic field already discussed above. sensor element technology to manufacture. In this case, the magnetic field sensor element can also comprise a Hall sensor element, a magnetoresistive sensor element or another corresponding magnetic field sensor element.

It should be noted in this context that because of the above-described problem of positioning tolerances in the context of a practical implementation of an embodiment of the magnetic field sensor 100, 300, the above-described symmetric properties of the various components may be about the symmetry line 195 The deviation is only within predefined tolerance limits, ie for example within a positioning tolerance, either in the lateral direction or in the vertical direction depending on the application. In other words, if the line of symmetry 195 is related to the center of e.g. two magnetic field sensor elements 190 on the substrate 180 of the magnetic field sensor arrangement 120, the two magnetic bodies 310, 320 which together form the back bias magnet may possibly be within a predefined Deviates from its corresponding position within the positioning tolerance. In many cases, the corresponding positioning tolerances are application specific and are indeed influenced by, for example, the technology of the magnetic field sensor element 190 used.

In addition, a generator object 210 is again drawn in Figures 10a and 10b, again eg a rack, magnet rod, drill rod, toothed wheel, drill wheel or magnet wheel. Depending on the particular application, other generator objects 210 may also be employed, and depending on the particular implementation, it may in many cases be useful to configure the respective generator object 210 such that it is capable of causing a modulation of the magnetic field, for example a periodic or sinusoidal modulation, which The magnetic field is generated (in particular) in this case by a first magnetic body 310 which is often configured as a permanent magnet and a second magnetic body 320 of a back-bias magnet or of a back-bias magnet arrangement.

With respect to the line of symmetry 195, in many embodiments of the magnetic field sensor 300, the first magnetic body 310 and the second magnetic body 320 are configured or arranged to be symmetrical about it. In addition to the above-mentioned possibility of carrying out the definition of the line of symmetry 195 with respect to the central position of the magnetic field sensor elements 190, there is naturally also a relation with respect to the center of the substrate 180 if the magnetic field sensor elements 190 are present in a corresponding number and arrangement. A dot or any other corresponding line or mark defines the possibility of the line of symmetry 195 . They each have a symmetrical mounting position about the line of symmetry 195 while taking into account positioning deviations or positioning tolerances of the individual magnetic bodies 310 , 320 , eg due to manufacturing tolerances.

As explained before, depending on the specific definition of the position of the line of symmetry 195 , the position of the two magnetic bodies 310 , 320 and/or the individual magnetic field sensor element 190 may include corresponding installation or positioning tolerances about the line of symmetry 195 . In other words, the centers of gravity of the two magnetic bodies 310, 320 may be spaced apart from the line of symmetry 195 by a distance typically smaller than the corresponding positioning tolerance.

The same applies not only in the x-direction, but also in the y-direction perpendicular to the x-direction, as plotted in FIGS. 10 a and 10 b . Depending on the production technology used, in particular with regard to the magnetic field sensor arrangement 120 with fixed magnets, positioning errors ranging from a few hundred µm to a few millimeters cannot therefore occur in the x- and/or y-direction as well as in the z-direction, z The directions are not shown in Figures 10a and 10b. In other words, corresponding positioning tolerances can be in the range of up to several hundred µm, ie in the range of up to approximately 1000 µm or in the range of up to approximately 2 mm.

With regard to the positioning of the individual magnetic field sensor elements 190 respectively relative to one of the two magnetic bodies 310, 320, in many embodiments of the corresponding magnetic field sensor 300 it is assumed that the magnetic field sensor elements 190 and/or the magnetic bodies 310, 320 are symmetrically Arranged, the magnetic field sensor elements 190 each comprise an x-coordinate within the range of the x-coordinate of one of the two magnetic bodies 310 , 320 . In other words, in such an embodiment of the magnetic field sensor 300 the associated magnetic field sensor element 190 is positioned above or below the respective magnetic body 310 , 320 .

With respect to the angle formed by the magnetization directions of the individual magnetic bodies 310, 320 and the line of symmetry 195 or line 350, line 350 extends perpendicular to line 195 and is also plotted in FIGS. 10a and 10b, in many embodiments of magnetic field sensor 300 , the angle of magnetization of one of the two magnetic bodies 310 forms an angle with the line of symmetry 195 between 10° and 80° in magnitude. In many embodiments of magnetic field sensor 300 , line of symmetry 195 extends perpendicular to the main surface or surface of substrate 180 having magnetic field sensor element 190 disposed thereon. Accordingly, the corresponding magnetization also forms an angle with respect to the line 350 ranging from 10° to 80° in magnitude. Furthermore, in the case of a symmetrical design of the two magnetic bodies 310 , 320 , the corresponding magnetizations in each case form an angle with one another in the magnitude range from 20° to 160°. Depending on the particular field of application, other angular ranges, which should be explained in more detail further down the course of the present application in the context of numerical simulations, may also occur in embodiments of the magnetic field sensor 300 .

The embodiments of the magnetic field sensor 300 depicted in Figures 10a and 10b differ substantially with respect to the arrangement of the two magnetic bodies 310, 320 relative to each other. While in the embodiment shown in FIG. 10a the two magnetic bodies 310, 320 adjoin each other closely, for example because they are fixed by means of gluing, in the embodiment shown in FIG. 10b the two magnetic bodies 310, 320 are separated from each other by corresponding gaps. The gap between the two magnetic bodies 310 , 320 may eg be filled with a magnetic or non-magnetic material, which eg serves to attach or serve the general architecture of the embodiment of the magnetic field sensor 300 . For example, a plastic attachment may be partially or fully inserted between the two magnetic bodies 310, 320 to which the two magnetic bodies 310, 320 are glued or otherwise attached. Alternatively or additionally, the two magnetic bodies 310 , 320 may also be fixed to each other within the framework of the overall installation of the magnetic field sensor arrangement 120 such that the encapsulation material at least partially enters between the two magnetic bodies 310 , 320 in the gap.

As already explained in the context of the embodiment of the magnetic field sensor 100 shown in FIGS. Part of it includes packaging.

Of course, in principle it is also possible that no solid material is interposed between the two magnetic bodies 310 , 320 , as shown in FIG. 10 b , but instead the two magnetic bodies 310 , 320 are directly connected or glued to the magnetic field sensor arrangement 120 . In this case, introducing material between the two magnetic bodies 310, 320 can possibly be dispensed with.

In the embodiment of the magnetic field sensor 300 shown in Figures 10a and 10b, two individual magnets as magnets 310, 320 are assembled to form a new magnet or a back-biased magnet such that again in equation (1) given The given symmetry conditions apply to the magnetization components of the overall arrangement of the two magnetic bodies. This again corresponds to a non-uniform (mostly) magnetization with respect to the general arrangement of the two magnetic bodies 310 , 320 . More specifically, this corresponds to a non-uniformly magnetized bulk magnet, each half of the volume of which consists of a uniformly magnetized magnetic body or a homogeneous region, respectively. In FIGS. 10 a and 10 b , in the embodiment of the magnetic field sensor shown there, the second cube is correspondingly combined with an inclined magnetization, as possibly the simplest example.

Depending on the particular implementation, for example, the two magnetic bodies 310, 320 may be configured as two bulk magnets having a width of about 2 mm and a height of about 5 mm, and may be bonded back-to-back to each other. Again depending on the particular implementation, the two individual magnetic bodies 310 , 320 are in this context uniformly magnetized with a remanence of about Brem = 1 T predominantly in the respective directions shown by the magnetizations or arrows 330 , 340 . In some embodiments, the magnetization direction may include, for example, an angle of +/- 50° with respect to the line of symmetry 195 , ie, perpendicular.

Some embodiments of the magnetic field sensor 300 corresponding to the arrangement of Figures 10a and 10b provide very good results with respect to combination with a magnetic field sensor arrangement comprising magnetoresistive sensor elements. In addition, they can often be produced in a particularly simple manner, since the respective magnetic bodies 310 , 320 as homogeneously magnetized individual magnets can be produced in a rather simple manner.

This is already the case in the context of the embodiment of the magnetic field sensor 300 shown in FIGS. Line 350 is mirrored so that magnetic field sensor element 190 incorporating the completed magnetic field sensor faces generator object 210 .

As schematically depicted in FIG. 10 b , the two magnetic bodies 310 , 320 can also be spaced apart from each other by a non-magnetic gap. Depending on the particular implementation, this may facilitate installation, for example, since a corresponding distance may be configured as an adhesive surface. In addition, there is also the possibility to influence the interaction of the two magnetic bodies 310, 320 by introducing such a non-magnetic gap, so that they may not overlap or influence each other to such a great extent.

Therefore, some embodiments of the magnetic field sensor 300 with a back-biased magnet formed by two magnetic bodies 310, 320 are based on the idea that when the field lines of a magnet diverge, a second magnet can be arranged close to this magnet, the second The magnet cancels out the undesired component of the first magnet.

Fig. 11 shows the results of a numerical simulation of the magnetic flux density distribution of the embodiment of the magnetic field sensor 300 as schematically shown in Fig. 10a. Apart from a number of field lines 230 , FIG. 11 shows the magnetic flux density distribution calculated in the region of the two magnetic bodies 310 , 320 and ranging from 0.2 to 0.5 T. FIG. As already schematically shown in FIG. 10 a , the two magnetic bodies 310 , 320 have a magnetization with a remanence of Brem=1 T, which is also indicated by arrows 330 , 340 in FIG. 11 . The resulting magnetic flux density distribution is reproduced according to the grayscale distribution depicted in FIG. , 320 external magnetic flux density.

In addition, FIG. 11 depicts a line 260 about which FIG. 12 a shows the x-component of the magnetic flux density Bx in the range from x=-2 mm to x=+2 mm for the y-coordinate of y=-1 mm. Here, the numerical simulation shown in FIG. 11 is based on two cubic magnets or magnetic bodies 310, 320 each having a uniform magnetization, however, the uniform magnetization forms a +/- 35° angle from the y or By axis extending vertically downwards. angle. There is thus an angle of 55° in magnitude between the two magnetizations of the two magnetic bodies 310 , 320 and the horizontal.

As briefly indicated above, Fig. 12a shows the x-component Bx according to the x-coordinate for a y-value of y = -1 mm, which corresponds to the line 260 shown in Fig. 11 . Subsequently, FIG. 12 b shows the corresponding x-component Bx of the magnetic flux density according to the x-coordinate for a y-value of y=−1.5 mm, which is however not plotted in FIG. 11 .

In the case of y values of y = -1 mm, Fig. 12a shows the variation of the magnetic flux density in the range from x = -2 mm to x = +2 mm for various angles of magnetization of the two magnetic bodies 310, 320 x component Bx. Here, the simulation is based on the above-explained symmetry of the magnetization directions of the two magnetic bodies 310, 320, each of which forms an angle with the horizontal in magnitude in each case using individual The reference marks of curve 270 are reproduced. The curves 270-70 are based on an angle of 70° of the magnetization of the two magnetic bodies 310, 320 to the horizontal such that for this simulation or calculation the magnetization of the two magnetic bodies forms an angle of 20° with the line of symmetry 195 of Fig. 10a. Thus, the curve 270-55 corresponds to the situation shown in FIG. 11 for an angle between the vertical symmetry line 195 and the horizontal line of 35°, or to an angle of magnetization and the horizontal line and 55°.

Fig. 12b thus shows several curves 270 for angles ranging from 40° to 70° formed by the magnetization of the two magnetic bodies 310, 320 and the horizon. Accordingly, the curves 270-40 to 270-70 depicted in FIG. 12b correspond to magnetizations of the magnetic bodies 310, 320 ranging from 20° (curve 270-70) to 50° with respect to the vertical line of symmetry 195 shown in FIG. 10a. ° (curve 270-40) angle. Especially in the case shown in Fig. 12b of the magnetic field sensor element 190 at a vertical distance of 1.5 mm from the lower edges of the two magnetic bodies 310, 320 (y = -1.5 mm; the magnets end at y = 0 mm), it is possible see the conditions < 20mT is fulfilled in the case of y = -1.5 mm in the other range of x-coordinates. Since this can also be fulfilled for the situation shown in FIG. 12a in the range of other x-coordinates, there is in particular the possibility of using Embodiments implement the magnetoresistive magnetic field sensor element 190 without driving the magnetic field sensor element 190 into saturation by the respective x-component of the magnetic field induced by the magnets 310 , 320 .

In other words, using embodiments of magnetic field sensor 300 , a horizontal component Bx (eg, x-component) of magnetic flux density can be created over a relatively wide range of x and y coordinates that does not cause saturation of magnetoresistive sensor element 190 . In the case of GMR sensor elements, Figures 12a and 12b thus show the conditions for many GMR sensor elements < 20mT can be satisfied over a wide range of x and y coordinates.

Furthermore, Figures 12a and 12b show that by changing the orientation of the two magnetic bodies 310, 320, the corresponding ranges can be shifted so that different distances between the magnetic field sensor elements 190 can be achieved. Thus, it is possible to provide different embodiments of the magnetic field sensor 300 with different mutual distances of the magnetic field sensor elements 190 .

In summary, it can be stated that by using a corresponding embodiment of a magnetic field sensor 300 comprising (at least) two magnetic bodies 310, 320, a magnetic system can be built such that the corresponding magnetic field sensor element 190 is for example even in sensitive magnetoresistive sensor elements, i.e. GMR sensors element without being driven into saturation.

Fig. 13 shows another embodiment of a magnetic field sensor 300 which differs from the embodiment of the magnetic field sensor 300 shown in Figs. Instead, the magnetization is perpendicular to the front side. In this case, the two magnetic bodies 310, 320 are no longer arranged in parallel with respect to their sides, as is the case in the embodiment in FIGS. 10a and 10b. Instead, in order to achieve two different magnetization directions of the two magnetic bodies 310 , 320 , they are now arranged for their parts at respective angles to the line of symmetry 195 or to a line 350 perpendicular to the line of symmetry 195 .

Therefore, in this case, the first magnetic body 310 and the second magnetic body 320 also include different first and second magnetization directions, respectively. Thus, also with this arrangement of the magnetic bodies 310 , 320 , a non-uniform majority magnetization is achieved by superposition of the magnetic fields of the two (uniformly magnetized) magnetic bodies 310 , 320 .

In other words, a corresponding arrangement of magnets 310, 320 respectively comprising different magnetization directions can be found with two cubic magnets or magnets instead of using two oblique or obliquely magnetized magnets 310, 320, the two cubic magnets or The magnets are magnetized in the longitudinal direction and are embodied and mounted such that they are inclined by a corresponding angle, for example +/−35°, relative to the y-axis. In other words, for an embodiment of the magnetic field sensor 300, it is irrelevant whether the two different magnetization directions of the two magnetic bodies 310, 320 as indicated by the arrows 330 and 340 are created by using magnetic bodies comprising different, inclined magnetizations It is irrelevant whether or not magnetic bodies comprising the same magnetization are used, which are however established in the context of the corresponding embodiment of the magnetic field sensor 300 in a correspondingly inclined manner or with a corresponding mounting orientation.

Regarding the more specific mounting positions of the individual magnetic bodies 310, 320 as in the embodiment depicted in Fig. 13, the above explanations will also apply, of course, the only difference in this case is that the respective magnetic bodies 310, 320 are now rotated accordingly .

In fact, there is a very large degree of freedom regarding the specific shape of the individual magnetic bodies 310,320. In principle, corresponding magnetic bodies of any conceivable shape can be used. For example, cubic, cylindrical, and other magnets (eg, tapered magnets) are feasible. Furthermore, of course, not only can homogeneously magnetized magnetic bodies be used in the context of two magnetic bodies 310, 320 as implicitly assumed in the previously described embodiments, but the use of non-uniformly magnetized magnetic bodies can naturally be made . In other words, the magnetic bodies 310 , 320 can also be implemented non-uniformly with respect to their magnetization direction and their magnetization strength.

Embodiments of the magnetic field sensor 100, 300 thus enable the reduction of the horizontal magnetic field component or the horizontal component of the magnetic flux density by using non-uniform magnetization of the magnetic body 110 or the back bias magnet, the latter comprising at least two magnetic bodies 310, 320 to such To such an extent that eg magnetoresistive sensors (xMR sensors) are no longer overloaded, ie driven into saturation. As already explained above, embodiments of the magnetic field sensor 100 thus enable the reduction of the flux density component of the Bx field, also tentatively referred to in the context of this application as a back bias magnet, by means of the described inhomogeneous magnetization to this to such an extent that a corresponding overload of the sensor or sensor element will not occur.

The exemplary embodiment of the invention in the form of a magnetic field sensor 100 , 300 achieves the desired field curve, since in particular the corresponding component of the resulting magnetic flux density is limited by the inhomogeneous magnetization of the magnetic bodies 110 , 310 , 320 . Thus, it is also possible to create embodiments of the magnetic field sensor 100, 300 without implementing magnetic bodies with extremely small shapes or recesses, or without using highly permeable parts as a Wire-deformable magnetic lenses are developed and corresponding embodiments of the magnetic field sensors 100, 300 are established. Embodiments of the respective magnetic field sensors 100 , 300 may be used in particular for magnetoresistive speed sensors, while employing respective back-bias magnet circuits in the form of magnets 110 , 310 , 320 . Examples of the use of corresponding embodiments of magnetic field sensors are found in the automotive industry as well as in other industries such as mechanical engineering, plant engineering, aircraft construction, shipbuilding and other technical fields in which detection of magnetic fields is required.

14A illustrates a cross-sectional view of another embodiment of a non-uniform magnet 400 suitable as a back bias magnet to be used in conjunction with magnetic sensor 120 as discussed above. The inhomogeneous magnet 400 is somewhat similar to the magnet 110 or the magnets 310 , 320 . It is noted, however, that the non-uniform magnet 400 does not include two different magnetic bodies of substantially uniform magnetization bonded together or in contact at a particular angle, resulting in the non-uniform magnetization described above. In contrast, the non-uniform magnet 400 may be molded as a single piece, which also includes the direction of magnetization as indicated by the arrows 14-1, 14-2, 14-3 at specific locations within the cross-sectional view of the magnet 400. non-uniform magnetization. The cross-sectional view of Figure 14A is shown along the xz plane, that is to say the _Bx component of the magnetization is indicated at the bottom of the figure, while the _Bz component of the magnetization is indicated to the left of the figure. It will be appreciated that this choice serves illustrative purposes and that magnet 400 may instead include non-uniform magnetization in other cross-sections. The magnetization illustrated in FIG. 14A is depicted relative to the line of symmetry 14-0 as represented by the dotted line.

Although the non-uniform magnetization of FIG. 14A is illustrated as being completely symmetric about the symmetry line 14-0, it will be appreciated that for an actual cross-section of the non-uniform magnet 400, various effects can break the symmetry of the magnetization within the cross-section. , so that the magnetization is no longer perfectly symmetrical. Such influences may be, but are not limited to, confining faces of the magnet 400 , (magnetic) impurities within the magnet 400 , and/or magnetic substances sufficiently close to the magnet. For purposes of this disclosure, the magnetization should be considered to be symmetrical in cross-section even if only 90%, 80%, or 50% of the cross-sectional area actually exhibits symmetrical magnetization in cross-section about the line of symmetry 14-0.

For the present disclosure (magnetization (as illustrated in FIG. 14 )), it is understood that this line of symmetry 14 - 0 may indicate a mirror-image symmetrical magnetization of the magnet 400 . Without limitation, the symmetry line 14 - 0 as indicated in the cross-section of FIG. 14A may indicate a higher order symmetry of the magnet 400 , say a third order or higher order symmetry. Objects of higher order symmetry include more than one cross-sectional plane, and some properties of the object (such as the magnetization of the object or crystal structure of a mineral, for example) are symmetric about or within the cross-sectional plane of. So for higher order lines of symmetry, there may be more than one cross-section presented, about which or within which the properties of the symmetric object are symmetric, and more than one cross-section actually intersect at a higher-order symmetry line.

It will be further appreciated that the line of symmetry 14-0 of the magnet 400 as shown in Figure 14A may actually indicate a rotational or elliptical axis of symmetry. So those of ordinary skill will readily appreciate that the back bias magnet 400 may also have rotational symmetry. Thus, any disclosures regarding non-uniform (back-biased) magnets such as back-biased magnet 400 can be transferred to objects of rotational symmetry. The rotational or elliptical symmetry of the magnet may be of interest depending on the circumstances. It will be appreciated that the elliptical axis of symmetry corresponds to rotational symmetry, where not just one radius but a rotation between the first and second radii produces the overall Elliptical properties.

As before the magnetization of higher order symmetry, rotational symmetry or elliptical symmetry in the cross-section should still be considered to be symmetric to higher order symmetry, rotational symmetry or elliptical symmetry, even if only 90% , 80% or 50% of the cross-sectional area actually exhibits a magnetization of higher symmetry about the symmetry line 14-0. Similarly, the magnetization of a back-biased magnet should be considered to be of higher order symmetry, rotational symmetry, or ellipsoidal symmetry, even if only 90%, 80%, or 50% of the volume of the magnet actually exhibits about the symmetry line 14- Higher symmetry magnetization of 0.

It will be noted that in the lower portion of the cross-sectional view (below or zero z-value), the magnetization of magnet 400 is almost completely aligned along the z-axis. However, with increasing z coordinate, the magnetization is increasingly non-uniform. That is to say, the higher the z-coordinate, the larger the angle α between the z-direction and the orientation of the magnetization, as can be seen from FIG. 14A when comparing the angle α for increasing z-coordinates. Clearly, the magnetizations are aligned parallel along the axis of symmetry 140-0. When walking parallel to the line of symmetry 14-0 but not on the line of symmetry (which is in the z direction for a given x coordinate), the angle α will increase substantially with increasing z values. This behavior can be referred to as monotonically, more precisely monotonically increasing.

If one were to walk along a path perpendicular to the line of symmetry 14-0, one could experience the non-monotonic nature of the angle α. That is to say, when traveling parallel to the line of symmetry 14-0, the angle α may first decrease until the line of symmetry 14-0 is reached and will increase again after passing the line of symmetry. Going perpendicular to the line of symmetry 14-0 in FIG. 14A would correspond to walking in the x direction for a given z value along the cross section.

Likewise, the angle a of the magnetization increases when going away from the line of symmetry in the horizontal direction (constant z-coordinate) for those portions of the magnet 400 that are not at the lower portion of FIG. 14 . The increasing non-uniform magnetization is best seen when comparing the angle α for arrows 14-1, 14-2 and 14-3. An alternative way to describe increasing non-uniform magnetization when walking along the z-direction (other than along the symmetry line 14-0) is to view it as increasing divergence. It will be appreciated that the cross-sectional distribution of magnetization serves for illustrative purposes only and does not limit the teachings of the present disclosure in any way.

Those of ordinary skill in the art will appreciate that it is feasible to use a molding process to produce most magnets including non-uniform magnetization as illustrated in Figure 14A. According to a first variant of this molding process, and somewhat similar to the discussion regarding the generation of radially magnetized magnets (Fig. 3a, 3b, respectively), the molding tool can be configured to generate a spatially varying Magnetic flux density while the magnetizable molding material is injected into the molding tool and/or is melted inside the molding tool. The spatially varying magnetic flux density inside the molding tool will project onto the magnetizable molding material and should persist once the molding process is complete, resulting in a mostly magnet 400 with non-uniform magnetization as a single component. In practice, the molding tool, magnetizable molding material, and spatially varying magnetic flux density inside the tool can be selected to achieve almost any desired spatially varying magnetic flux density inside the magnet 400 once the molding process is complete.

It will be appreciated that alternative molding processes can be used to produce most magnets including non-uniform magnetization as illustrated in Figure 14A. The molding tool can be filled with standard magnetizable or magnetic molding materials and can be hardened in the desired form of the inhomogeneous magnet to be produced. It is conceivable that no external magnetic field or a homogeneous external magnetic field may be applied during hardening of the inhomogeneous magnet to be produced. This will result in a magnet showing more or less vanishing or uniform magnetization. Once the magnetizable molding material has hardened, a non-uniform external magnetic field may be applied to the hardened molding material in the shape of the non-uniform magnet to be produced. It may be advantageous to apply the non-uniform magnetic field to the hardened molding material while it is still in the molding tool. This approach may have advantages as the non-uniform magnet 400 exits the molding tool. This method can be used to increase the required trade-off time per unit inside the molding tool. Depending on circumstances, however, it may be of interest to move the hardened molding material in the shape of a non-uniform magnet into a magnetizing device that provides a sufficiently large non-uniform magnetic field projected in the shape of a non-uniform magnet to a magnetizable on the hardened molding material; thus completing the fabrication of the non-uniform magnet 400 according to the present disclosure.

FIG. 14B illustrates an exemplary shape of a non-uniform magnet 400 according to the present disclosure. It may be convenient to provide the magnet 400 in a brick, ie cubic, or slightly tapered brick shape, as shown in Figure 14B. This shape may be of interest in order to replace known back bias magnets with moldable non-uniform magnets 400 . The back bias magnet supplier will typically overmold the back bias magnet 400 and sensor arrangement 120 (not shown) in order to build a module sold to the supplier's customer which now includes communication from the sensor elements to the ECU means, which are not discussed in detail with respect to the present disclosure.

Without limitation, the sensor 100 (see FIG. 2 ) built by the automotive supplier may also have a brick shape as shown in FIG. 14B , while the means of communication from the sensor element to the ECU is not shown. The sensor 100 can also have a rotationally symmetrical or elliptically symmetrical shape. The rotationally or elliptically symmetrical sensor 100 may optionally take the shape of a truncated cone depending on the circumstances. Those of ordinary skill will understand that the oval shape of the sensor 100 may have the advantage that rotation of the sensor 100 when installed is only provided by the vehicle within the vehicle that matches the oval shape and thereby places the sensor 100 in the intended location. Some casing is easily prevented.

If the sensor 100 still has rotational symmetry, grooves or indentations at the face of the sensor may be provided in order to provide an arrangement of the sensor as achievable for an elliptical shape. It may be advantageous to arrange the grooves or notches away from the magnetic field sensor arrangement 120 so that the grooves or notches do not affect the magnetic field distribution close to the magnetic field sensor arrangement 120 (not shown).

FIG. 14C illustrates this shape for sensor 100 , which includes groove 101 away from sensing element 190 . Such a notch may snugly fit a protrusion within a housing of the sensor 100 provided in a device in which the sensor is used, such as a vehicle. As an alternative to notches, the frusto-conical sensor 100 may include non-parallel top and bottom faces (more generally, non-parallel, non-circumferential faces) so that the sensor 100 will only snugly fit corresponding shell. Other options for positioning the rotationally symmetric sensor 100 within the corresponding housing will be apparent to those of ordinary skill in the art, and therefore should not be explained any further here.

FIG. 14C discloses another alternative for implementing the sensor 100 . In the embodiment of FIG. 2 , the sensor element 190 is arranged in a sensor package forming the magnetic field sensor arrangement 120 . Unlike in FIG. 2 , the sensor 100 of FIG. 14C does not include a package forming the magnetic field sensor arrangement 120 . It will be noted that one packaging/molding step can be saved by implementing the sensor 100 using the bare chip 195 carrying the sensor element 190 without packaging. Such an embodiment of the sensor 100 would be more cost-effective for the (automotive) supplier. As a trade-off, care needs to be taken that the sense element 190 and thus the die chip 195 are spatially correctly arranged with respect to the back-bias magnet 400 . While their correct alignment in previous implementations of the sensor 100 was catered to by chip manufacturers, correct alignment will now be a task left to the supplier.

Although there is a spatial distance between back bias magnet 400 and die chip 195 in FIG. to the back bias magnet 400. Those of ordinary skill will appreciate that die chip 195 typically requires some coupling means in order to provide electrical communication from die chip 195 to its exterior. This means of providing electrical communication may be in the form of a lead frame, but is not limited thereto. Those of ordinary skill will appreciate other options for providing electrical communication, which do not limit the teachings of the present disclosure and thus are not described in further detail. For the remainder of this disclosure, die chip 195 should be construed as optionally including coupling members. In various embodiments, the die chip 195 design of the back bias magnet 400 facilitates proper spatial placement of the die chip 195 relative to the back bias magnet 400 .

FIG. 14D illustrates another alternative to implementing the sensor 100 including a back bias magnet 400 . Indeed, for the embodiment of FIG. 14D , the inhomogeneous magnet 400 also acts as a housing for the sensor 100 . By properly controlling both the spatial distribution of the non-uniform magnetization of the magnet 400 and the positioning of the die chip 195 relative to the non-uniform magnetization, packaging covering the sensing element 190 and additional molding material to provide an enclosure can be saved. In FIG. 14D, the spatial distribution of the magnetization is substantially symmetrical about the line of symmetry 14-0, which shows different degrees of non-uniformity 14-1, 14-2, 14-3 with respect to the angle α, as with respect to Figure 14 explains.

It will be appreciated that the non-uniform magnet 400 has advantages when used with the magnetic field sensor arrangement 120 because less magnetic material is required in order to achieve a comparable non-uniform magnetic flux density at the sensor element 190 . This is due to the fact that the magnet 400 (see Figs. 14A, C, D) can be arranged closer to the magnetic field sensor arrangement 120, where say the first and second sensor elements 190-1, 190-2 (see Figs. 14C, 14D) are placed for a magnet arrangement that does not have a convex shape as magnet 400 .

As another benefit of magnet 400, sensor 100 and/or magnet 400 require less space than those systems that include non-convex magnets (such as, for example, magnet 150 of FIG. 1A, magnet 110 of FIGS. 3A, 3B, 6A, or 6B). . In space constrained environments such as the engine space of internal combustion engines in the automotive field, smaller size back-biased sensor systems are of interest.

It is noted that the moving target wheel rotating in direction 220 is shown in FIGS. 14C and 14D for illustrative purposes only, and does not form part of the (back-biased) sensor 100 depicted.

Those of ordinary skill in the art will appreciate that the non-uniform magnet 400 may be formed using, respectively, a hard ferrite material or a rare earth material as the magnetizable molding material, such as ferrite, aluminum-nickel-cobalt (AlNiCo ), or samarium cobalt (SmCo) or neodymium-iron-boron (NdFeB), to name some non-limiting examples.

In general, hard ferrite magnets are less expensive than rare earth based magnets, which as such will reduce magnet cost, however hard ferrite magnets have a weaker magnetic moment and therefore, when compared to rare earth based magnets, for the same A uniform magnet of size will produce a weaker uniform magnetic field. To compensate for this trade-off, the use of non-uniform hard ferrite magnets according to the present disclosure facilitates increasing their corresponding magnetic fields to match the magnetic field strength of rare earth magnets at the cost benefit of hard ferrite magnets. In the past, rare earth magnets have been conveniently used for the non-convex magnets described above (see, eg, magnet 150 of FIG. 1A , magnet 110 of FIGS. 3A, 3B, 6A or 6B). Thus, the inhomogeneous magnet 400 employing hard ferrite material presents another advantage over non-convex magnets made of rare earth magnet materials such as samarium cobalt (SmCo) or neodymium-iron-boron (NdFeB).

Figure 15 schematically illustrates the B _x component relative to the magnet's line of symmetry (x=0) for a given y coordinate. In this respect, the illustration of FIG. 15 corresponds somewhat to the situation depicted in FIG. 5 as explained above. It becomes apparent that while the B _x component for a uniform magnet (see solid line 15-3) has an odd symmetry about x = 0, the B for a non-uniform magnet (say, magnet 400 as discussed above) The _x -component almost disappears over a large range of x-coordinates, as can be seen from the long dashed line 15-4. Short dashed lines 15-1 and 15-2 indicate typical locations for magnetoresistive sensors such as GMR sensing elements.

As previously discussed with respect to curve 270-6 (see FIG. 5), the _Bx component of the non-uniform magnet 400 shows an increased linear range, and thus would represent a preferred location for the GMR sensor element. The magnetic field sensor element 190 (i.e., FIG. 2 ) can conveniently be positioned symmetrically about x=0 over a wider range of x than for a uniform magnet (see line 15-3 of FIG. 15 ), as indicated by position line 15-3, respectively. 1. As indicated in 15-2. In Fig. 15, for the simulated magnetic field components (see lines 15-3 and 15-4) for uniform and inhomogeneous magnets, the distance of the sensor plane with the sensor elements is 0.7 mm above the magnet in the z direction. As indicated, the sensor elements show a sensor pitch or distance of 2.5 mm in the x-direction.

FIG. 16 illustrates a 3D plot for an exemplary simulation of the magnetization of the non-uniform magnet 400 of FIG. 14 using a standard polymer bonded hard ferrite molding material. These molding materials typically show a residual magnetic field of about 270-280 mT, and a corresponding diamagnetic resistance of 180 kA/m. As can be clearly seen, the spatial distribution of the magnetization within the magnet 400 is not uniform, as already discussed schematically with respect to Fig. 14A. The color coding indicated on the scale to the right of Figure 16 illustrates the strength and direction of the magnetization. It will be appreciated that the magnetization of the non-uniform (back-biased) magnet 400 will induce a magnetic flux density outside the magnet 400, unlike a so-called Halbach magnet arrangement, which represents a magnet configuration with nearly all of the magnetic flux density confined inside the Halbach magnet . Such confinement of magnetic flux to the interior of the magnet would be achievable with non-Halbach magnets if the magnet would be infinitely long, tall and/or wide. Also from FIG. 16 , one of ordinary skill in the art will readily appreciate that almost any desired non-uniform distribution of magnetization within magnet 400 can be generated, as already explained above.

FIG. 17 illustrates further details derived from the simulation of FIG. 16 . Shown are the plots in mT of the magnetic field generated by the magnet 400 for the actual distance of the sensor element in the y and z directions respectively from the surface of the magnet 400 centered on the line of symmetry (see 14-0 of FIG. 14 ). Simulates the B _x component. The assumed distance is 0.7mm in z-direction and centered in y-direction (y=0mm).

Line 17 - 1 illustrates the B _x component for a substantially uniform magnet, while lines 17 - 2 , 17 - 3 , and 17 - 4 show the B _x component for increasing non-uniform magnets 400 . The increasing non-uniformity shown for lines 17-2, 17-3, 17-4 can be explained by the increasing angle α associated with lines 14-0 to 14-1, 14-2 and 14-3 (see Fig. 14) Representation. As already discussed with respect to FIG. 15, the increasing non-uniform magnetizations shown in FIG. 17 for lines 17-2, 17-3, 17-4 are to be placed at Linear range of the magnetoresistive sensor element 190 (not shown) in the x-direction.

Since the _Bx component for the strongest non-uniformity represented by line 17-4 nearly disappears at sensor locations 15-1, 15-2, respectively, this amount of non-uniformity for the _Bx component will cause sensor location 15-1 and 15-2 are ideal locations for placing sensor elements in the x-direction, as previously described with respect to FIG. 5 .

Those of ordinary skill in the art will appreciate that the present disclosure depicts a cross-section of a non-uniform magnet such as the non-uniform magnetization of magnet 400 in the xy or xz plane for illustrative purposes only (see, FIGS. 1A, 1B, 3A, 3B , 4-14, 14A, 14D, 15-17). However, the disclosed non-uniform magnets are by no means limited to this case. The magnet may thus include additional inhomogeneous magnetization contributions in additional cross-sections of the magnet, the additional cross-sections being perpendicular to those depicted in the figures of this disclosure.

Depending on conditions, embodiments of the inventive method can be implemented in hardware or in software. The embodiments may be implemented on a digital storage medium, in particular a disk, CD or DVD including electronically readable control signals, which may cooperate with a programmable computer system such that embodiments of the inventive method are carried out. In general, embodiments of the invention therefore also reside in a software program product, or a computer program product, or a program product comprising program code stored on a machine-readable carrier for use when the software program product is run on a computer or Embodiments of the inventive method are executed on a processor. In other words, the embodiments of the present application can thus be realized as a computer program, or as a software program, or to an extent comprising program code for performing embodiments of the method when the program is run on a processor. The processor can be formed respectively by a computer, a chip card (smart card), a central processing unit (CPU=central processing unit), an application specific integrated circuit (ASIC) or any other integrated circuit.

A computer program, a software program or a program may be employed eg in the context of a manufacturing process, ie eg for controlling the manufacture of a corresponding embodiment of the magnetic field sensor. Corresponding programs can thus be adopted and used within the context of the production plant for controlling it, but also within the context of the design and within the context of the corresponding embodiments of the arrangement of the magnetic field sensors. As the above list already shows, a processor is to be understood not only in the sense of classical computer processing, but also in the sense of a special-purpose processor as eg occurs in the context of machine tools and other production-related installations.

While this invention has been described in terms of several embodiments, there are modifications, permutations, and equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the invention. Therefore, the appended claims should be interpreted as all such modifications, permutations and equivalents as fall within the true spirit and scope of the invention.

Claims (20)

1. a kind of magnetic field sensor, including：

Magnetic field sensor is arranged；And

Back of the body lift magnet, described back of the body lift magnet includes Uneven Magnetization.

2. magnetic field sensor as claimed in claim 1, wherein said back of the body lift magnet may be molded as solid memder And it is cuboidal shape, round-shaped, oval or truncated cone.

3. magnetic field sensor as claimed in claim 2, wherein said back of the body lift magnet is included selected from following The material of the group that item is constituted：Ferrite, aluminum-nickel-cobalt（AlNiCo）, samarium-cobalt (SmCo) or Nd-Fe-B（NdFeB）.

4. magnetic field sensor as claimed in claim 1, the Uneven Magnetization of wherein said back of the body lift magnet is in the back of the body Symmetrical with regard to the first line of symmetry at least one cross section of lift magnet.

5., as magnetic field sensor required for protection in claim 4, the wherein first line of symmetry is at least the one of back of the body lift magnet The line of symmetry of the substantially mirror symmetric Uneven Magnetization in individual cross section.

6. as magnetic field sensor required for protection in claim 4, wherein at least one cross section of back of the body lift magnet First line of symmetry is the line of symmetry of higher order, rotationally symmetrical or ellipsoidal symmetry.

7., as magnetic field sensor required for protection in claim 4, wherein Uneven Magnetization is further with regards to back of the body lift magnet Line of symmetry in another cross section is symmetrical, and another cross section is intersected with described cross section at line of symmetry.

8. magnetic field sensor as claimed in claim 1, the Uneven Magnetization of wherein said back of the body lift magnet causes Magnetic density outside described back of the body lift magnet.

9. magnetic field sensor as claimed in claim 3, the magnetic flux wherein being caused by magnetization is not substantially limited System is in the inside of described back of the body lift magnet.

10. magnetic field sensor as claimed in claim 1, wherein said back of the body lift magnet includes carrying on the back lift magnet Uneven Magnetization at least the 50% of volume.

Described in magnetic field sensor required for protection, wherein first direction and second direction leap in 11. such as claim 4 at least One cross section, the first and second directions are not parallel, and

Wherein when the given coordinate figure for first direction is walked along second direction, magnetized local direction and second direction Between angle at least in the partly interior change of walking path, walking path is different from the first line of symmetry.

Magnetic field sensor required for protection in 12. such as claim 11, wherein said angle is when walking along walking path Monotone variation.

Magnetic field sensor required for protection in 13. such as claim 11, if wherein walking path extends perpendicular to line of symmetry, Then described angle non-monotonic change when walking along walking path.

14. magnetic field sensors as claimed in claim 1, wherein said magnetic field sensor arrangement includes the first magnetic field Sensor element and the second magnetic field sensor elements, the first magnetic field sensor elements are arranged to respect to back of the body lift magnet, make The first magnetic field sensor elements with regard to predetermined space direction be exposed to by the back of the body lift magnet cause and in the first flux Magnetic density in density range, and the second magnetic field sensor elements are arranged to respect to back of the body lift magnet so that the Two magnetic field sensor elements with regard to predetermined space direction be exposed to by the back of the body lift magnet cause and in the second flux density In the range of magnetic density.

Magnetic field sensor required for protection in 15. such as claim 14, the wherein first flux density range and the second flux are close Degree scope is capable of the operation of the first and second magnetic field sensor elements outside saturation range.

Magnetic field sensor required for protection in 16. such as claim 14, the wherein first and second flux density range only include It is less than or equal to the value of 20 mT in terms of amplitude.

Magnetic field sensor required for protection in 17. such as claim 14, the wherein first flux density range includes logical with second The flux density of metric density scope opposite sign.

Magnetic field sensor required for protection in 18. such as claim 15, the wherein first and second magnetic field sensor elements are magnetic Resistance sensor element.

Magnetic field sensor required for protection in 19. such as claim 15, the wherein first and second magnetic field sensor elements are by cloth Put on substrate, and wherein predetermined space direction is arranged essentially parallel to the first type surface of substrate.

20. magnetic field sensors as claimed in claim 1, wherein back of the body lift magnet is annular, or includes ring Tee section.