DE102016009010A1 - magnetic field sensor - Google Patents

Abstract

One embodiment of a magnetic field sensor includes a magnetic field sensor assembly and a magnetic body having, for example, a non-convex cross-sectional area with respect to a cross-sectional plane passing through the magnetic body, the magnetic body comprising inhomogeneous magnetization.

Description

This application is a continuation-in-part of US Patent Application No. 14 / 290,780 entitled "Magnetic Field Sensor" filed Mar. 29, 2014 entitled Excretion of US Patent Application No. 12 / 130,678 entitled "Magnetic Field Sensor""Magnetic Field Sensor", which was filed on 30.05.2008 and the priority right of German Patent Application No. 10 2007 025 000.4 filed May 30, 2007, all of which applications are hereby incorporated by reference.

TECHNICAL AREA

Embodiments of the present invention relate to a magnetic field sensor that includes a magnet, also referred to as a back-bias magnet.

BACKGROUND

In many fields of technology, for example, magnetic field sensors are used to detect movements of objects. In some applications, a magnetic field acting on the magnetic field sensor is influenced by the movement of the respective objects so that conclusions about the movement of the object based on the change of the magnetic field detected by the magnetic field sensor can be drawn.

Examples are found, inter alia, in the field of automotive applications, wherein, for example, the movement of the wheels in the context of an ABS application (ABS = Antilock Braking System) is monitored, for example using respective magnetic field sensors. Other automotive applications include monitoring or monitoring the motion of crankshafts, camshafts and other shafts in the field of automobiles.

Depending on the specific implementation of the respective magnetic field sensors, they comprise so-called back-bias magnets, which are arranged in a fixed arrangement with respect to the actual magnetic sensor elements 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 partially caused by the back-bias magnet. The object whose movement is to be monitored, for example, via the magnetic field sensor, possibly influences and / or supplements the overall magnetic field, which is then detected by the magnetic field sensor, by means of its own magnets or magnetic components.

Depending on the technique used in conjunction with the actual magnetic field sensor elements, back-bias magnets, which are often implemented as permanent magnets, have other requirements. This may be taken into account, inter alia, in that some magnetic field sensor element technologies are sensitive to different magnetic field components, exhibit different responses to magnetic fields, and include different magnetic field boundaries specific to the particular type.

SUMMARY OF THE INVENTION

An embodiment of a magnetic field sensor includes a magnetic field sensor assembly and a magnetic body having a non-convex cross-sectional area with respect to a cross-sectional plane passing through the magnetic body, the magnetic body having inhomogeneous magnetization.

Another embodiment of a magnetic field sensor includes a magnetic field sensor array, a first magnetic body having a first magnetization direction, and a second magnetic body having a second magnetization direction, wherein the first and second magnetization directions are different from each other.

An embodiment of a method of manufacturing a magnetic field sensor includes providing a magnetic body having a non-convex cross-sectional area with respect to a cross-sectional plane passing through the magnetic body, the magnetic body having inhomogeneous magnetization, first and second spatial regions on the magnetic body, so that in the first space region, a magnetic flux density caused by the magnetic body is in a first flux density region with respect to a predetermined spatial direction, and so in the second spatial region, a magnetic flux density through the magnetic body with respect to the predetermined Spatial direction, which is within a second range of flux density, and arranging a magnetic field sensor arrangement comprising a first and a second magnetic field sensor element, such that the first magnetic field sensor element is arranged in the first space region and the second magnetic field sensor element is arranged in the second space region.

Another embodiment of a method of manufacturing 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 with the first and second magnetization directions different, a first space area, and a second space area with respect to the first magnetic body and the second magnetic body, so that in the first space region, a magnetic flux density is caused by the first magnetic body and the second magnetic body with respect to a predetermined spatial direction, wherein the magnetic flux density is within a first range of flux density, and such that in the second space region a magnetic flux density is caused by the first magnetic body and the second magnetic body with respect to a predetermined spatial direction, the magnetic flux density being within a second spatial range A flux density range, and providing a magnetic field sensor arrangement comprising a first and a second magnetic field sensor element, such that the first magnetic field sensor element is arranged in the first space region and the second magnetic field sensor element is arranged in the second space region.

In accordance with some embodiments, the present disclosure teaches a magnetic field sensor that includes a magnetic field sensor assembly and a back-bias magnet. The back-bias magnet comprises an inhomogeneous magnetization.

According to some embodiments, the present disclosure teaches that the back-bias magnet is shapeable as a unitary member and of cube shape, circular shape, elliptical or truncated shape.

According to some embodiments, the present disclosure teaches that the back-bias magnet comprises materials selected from the group consisting of ferrites, aluminum-nickel-cobalt (AlNiCo), samarium-cobalt (SmCo), and neodymium-iron-boron (NdFeB).

According to some embodiments of the present disclosure, the inhomogeneous magnetization of the back-bias magnet is symmetrical to a first line of symmetry within at least one cross-section of the back-bias magnet.

According to some embodiments of the present disclosure, the first line of symmetry is a line of symmetry of substantially mirror-symmetric inhomogeneous magnetization within the at least one cross-section of the back-bias magnet.

According to some embodiments of the present disclosure, the first line of symmetry within the at least one cross-section of the back-bias magnet is a line of symmetry of higher order, rotational symmetry or ellipsoid symmetry.

Further, in accordance with some embodiments of the present disclosure, the inhomogeneous magnetization is symmetrical about the line of symmetry within another cross section of the back bias magnet, the further cross section intersecting the cross section at the line of symmetry.

According to some embodiments of the present disclosure, the inhomogeneous magnetization of the back-bias magnet causes a magnetic flux density outside the back-bias magnet.

According to some embodiments of the present disclosure, the magnetic flux caused by the magnetization is substantially not enclosed in the interior of the back-bias magnet.

According to some embodiments of the present disclosure, the back-bias magnet comprises the inhomogeneous magnetization in at least 50% of a volume of the back-bias magnet.

According to some embodiments of the present disclosure, the at least one cross section is spanned by a first direction and a second direction, wherein the first and second directions are not parallel, and when passing for a given coordinate value of the first direction along the second direction, an angle between the second direction and a local direction of Magnetization varies over at least a portion of the path, the path deviates from the first line of symmetry.

According to some embodiments of the present disclosure, the angle varies monotonically as one walks along the path.

According to some embodiments of the present disclosure, the angle does not vary monotonically when traveling along the path if the path is perpendicular to the line of symmetry.

According to some embodiments of the present disclosure, the magnetic field sensor assembly includes a first magnetic field sensor element and a second magnetic field sensor element. The first magnetic field sensor element is arranged, with respect to the back bias magnet, to expose the first magnetic field sensor element, with respect to a predetermined spatial direction, to a magnetic flux density caused by the back bias magnet and within a first range of flux density. However, the second magnetic field sensor element is arranged such that the second magnetic field sensor element is exposed to a magnetic flux density caused by the back bias magnet and within a second flux density region with respect to the back-biased magnet with respect to the predetermined spatial direction.

According to some embodiments of the present disclosure, the first flux density range and the second flux density range allow operation of the first and second magnetic field sensor elements outside a saturation region.

According to some embodiments of the present disclosure, the first and second flux density ranges only include values less than or equal to 20 mT.

According to some embodiments of the present disclosure, the first flux density range includes flux densities of the opposite polarity from the second flux density range.

According to some embodiments of the present disclosure, the first and second magnetic field sensor elements are magneto-resistive sensor elements.

According to some embodiments of the present disclosure, the first and second magnetic field sensor elements are disposed on a substrate, and the predetermined spatial direction is substantially parallel to a main surface of the substrate.

According to some embodiments of the present disclosure, the back-bias magnet is annular or comprises an annular portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are explained below with reference to the attached drawings, wherein:

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

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

2 a schematic representation of a possible exemplary use of an embodiment of a magnetic field sensor shows;

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

4 shows a result of a numerical simulation of a resulting magnetic flux density in the case of an embodiment of a magnetic field sensor and an associated back-bias magnet;

5 a representation of an x component of the magnetic flux density in the case of in 4 shows back-bias magnets shown;

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

7 shows a result of a numerical simulation of a magnetic flux density for an embodiment of a magnetic field sensor or an associated back-bias magnet;

8th a plot of x components of the magnetic flux density for the in 7 shows numerical simulation shown;

9 an enlarged representation of in 8th shows curves shown;

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

11 shows a result of a numerical simulation with respect to a magnetic flux density of an embodiment of a magnetic field sensor;

12a and 12b different curves of x components of the magnetic flux density for the in 11 show numerical simulation shown;

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

14A a cross-sectional view of another inhomogeneous magnet according to the present disclosure shows;

14B shows a spatial view of an exemplary form of the further inhomogeneous magnet;

14C shows the inhomogeneous back-bias magnet in combination with a nude-chip sensor;

14D another implementation of the inhomogeneous back-bias magnet according to the present disclosure shows;

15 shows a B _x component for an inhomogeneous and a homogeneous magnetic field;

16 shows a simulated distribution of magnetization for the further inhomogeneous magnet; and

17 shows simulated B _x components for different α angles indicating different levels of inhomogeneous magnetization for the further magnet.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

1a to 13 show schematic representations of various embodiments of magnetic field sensors with their magnetic bodies or back-bias magnets and results of numerical simulations in the form of curves and other representations. However, before a more detailed description of a potential application scenario of a magnetic field sensor is related to 2 First, a description will be given of a first embodiment of a magnetic field sensor together with a magnetic body or back-bias magnet in connection with FIG 1a given.

1a shows a first embodiment of a magnetic field sensor 100 who has a magnet body or back-bias magnet 110 and a magnetic field sensor arrangement 120 includes. The magnetic body 110 in 1a includes a recess 130 , that of the magnetic field sensor arrangement 120 and a polygonal cross-section with respect to a cross-sectional plane passing through the magnetic body as in 1a shown extends.

Here shows the recess 130 a polygonal cross-section with a total of seven corners 140-1 to 140-7 in the embodiment shown in FIG 1a is shown on. Unlike the cross-sectional shape of the magnetic body 110 , in the 1a The recess can be shown 130 of the magnetic body 110 in other embodiments of a magnetic field sensor 100 also a number of corners 140 include, which deviates from seven. For example, in a case of a triangular recess with respect to the respective one Cross-sectional plane passing through the magnetic body 110 runs, these only three corners 140 include. In general, however, any number of corners 140 the respective cross-sectional shape of the recess 130 define with respect to the cross-sectional plane.

With respect to the extent and shape of the magnetic body 110 perpendicular to the cross-sectional plane of 1a may be a respective magnetic body 110 For example, the same cross-sectional shape with respect to a cross-sectional plane, over the in 1a shown cross-sectional plane or perpendicular thereto include. In other words, depending on the specific implementation of the recess 130 the same shape of the recess with respect to a cross-sectional plane passing through a center point or any other fixed point arise. For example, in such a case, the set of all possible vertices 140 with respect to a plane perpendicular to the in 1a shown corner form a circular and / or elliptical set of points or possibly a set of points, which has the shape of a partial circle or a partial ellipse.

In other embodiments of a magnetic field sensor 100 can the magnetic body 110 other forms of recess 130 with respect to a plane that is not the cross-sectional plane. For example, such a recess 130 with respect to a plane perpendicular to the in 1a level shown include a cross-sectional shape that deviates from it. Thus, it is possible, for example, that the respective recess 130 in the form of a groove within the magnetic body 110 is implemented, so that in this case a respective cross section through the respective magnetic body 110 For example, a rectangular shape, a square shape or any other shape that is convex.

Of course, there are other configurations of a magnetic body 110 an embodiment of a magnetic field sensor 100 , wherein the respective cross-sections perpendicular to the in 1a level shown also have polygonal, elliptical or any other cross-sectional shape.

In addition, of course, other arrangements of a magnetic body 110 which is magnetized in an inhomogeneous manner, in embodiments of a magnetic field sensor 100 be used. For example, the magnetic body 110 which is magnetized in an inhomogeneous manner with respect to the straight line connecting 160 , in the 1a is drawn as a dotted line, and / or with respect to the non-convex cross-sectional shape which is generally defined herein, also assume a "mirror-like" cross-sectional shape as long as the magnetic body 110 is magnetized in an inhomogeneous way.

However, in the embodiments presented below, particular reference should be made to non-convex magnetic bodies 110 to simplify the description, however, the following drawings are basically applied to all magnetic bodies 110 which are magnetized in an inhomogeneous manner are applicable.

The magnetic body 110 as he is for example in 1a Thus, a non-convex cross-sectional area is included 150 with respect to a cross-sectional plane passing through the magnetic body 110 runs. In this context, a set of points within a plane, that is z. B. also the cross-sectional areas as the cross-sectional area 150 , if and only convex, if it is true for any two points of the respective set that the direct straight connecting line between these two points also runs entirely within the respective set, ie within the cross-sectional area 150 , In other words, a set within a plane is convex if and only if all possible straight connecting lines of all possible points of the respective set are entirely within the set.

As explained above, the cross-sectional area 150 of the magnetic body 110 non-convex, because, for example, a straight connecting line 160 as a dotted line in 1a whose endpoints are both within the cross-sectional area 150 are arranged, that is, elements of the respective amount, but not entirely within the respective amount, ie within the cross-sectional area 150 , lies. Rather, the connecting line cuts 160 the recess 130 , The cross-sectional area 150 is therefore non-convex, so that it can also be called concave. The terms concave and non-convex can therefore be used interchangeably if necessary.

The magnetic body 110 the embodiment of a magnetic field sensor 100 as he in 1a can be shown for. B. be made of a permanent magnetic material. Depending on the boundary conditions, under which an embodiment of a magnetic field sensor is used, not least in terms of potential operating temperatures, costs, useful magnetic fields and other parameters, the magnetic body 110 also, for example, iron, cobalt, nickel or other relatively complex compositions and Compounds that may include the above-mentioned metals as components, be prepared. In general, respective magnetic bodies or back-bias magnets 110 made of ferrites, aluminum-nickel-cobalt (AlNiCo), also made of samarium-cobalt (SmCo) or neodymium-iron-boron (NdFeB). Of course, other combinations of materials or materials as a field of application for the respective magnetic body 110 conceivable.

As in 1a through the arrows 170 has displayed the magnetic body or the back-bias magnet 110 an inhomogeneous magnetization. The magnetization M of the magnetic body 110 was here produced intentionally inhomogeneous, with different magnetizations at different points, especially within the cross-sectional area 150 occur that differ at least in terms of their size or intensity and / or their direction.

In other words, magnetization of a magnetic body is inhomogeneous unless it is largely homogeneous, and homogeneous magnetization in the context of this application is understood to mean magnetization that is constant and rectified with respect to its direction and intensity. In other words, the magnetic body 110 an inhomogeneous magnetization, as indicated by the arrows 170 is shown, since its magnetization in the vector sense does not have a constant direction and / or a constant amount of the magnetization M over the entire magnetic body or over a substantial proportion of the entire magnetic body. In the context of the present application, an essential portion of the entire magnetic body 110 or the magnetic body 110 as a volume fraction of the magnetic body 110 which ranges from 50% to 100%, ie, for example, 95%, 90%, 80%, 75%, 70% or 60%, whereby the respective volume fractions may result depending on the different field of application and implementations of an embodiment of a magnetic field sensor.

In addition, it should be noted at this point that in many magnets that have a magnitude and direction constant magnetization in the entire volume, which are thus homogeneously magnetized, the resulting magnetic field both in the outer region of the magnet and in the interior of the magnet be inhomogeneous can. In other words, therefore, the presence of an inhomogeneous magnetic field in the outer and / or inner region of a magnet is not necessarily an indication that the magnetization is also inhomogeneous. Homogeneous magnetizations are in many cases particularly attractive because they are relatively easy and inexpensive to produce.

The magnetic body 110 or the back-bias magnet 110 the embodiment of the magnetic field sensor 100 as he is for example in 5a is often shown to have a remanent magnetic flux density which varies between several hundred millitesla (≥ 100 mT) to several tesla (3 T), depending on the example used. Depending on the particular implementation and specification of an embodiment of a magnetic field sensor 110 can the magnetic body 100 Thus, for example, have a "magnetization" or prevailing due to the magnetization remanent magnetic flux density Brem of typically 500 mT or 1 T. However, it should be noted in this connection that the above-mentioned flux density ranges should not be considered in a limiting sense. Rather, they simply serve as examples that in some application fields of embodiments of a magnetic field sensor 100 can be used. In principle, other magnetizations can also be used depending on various parameters, such as the technology of the individual magnetic field sensor elements, the dimensions of the relevant magnetic field sensor and other parameters.

In addition to the magnetic body or the back-bias magnet 110 includes the in 1a shown embodiment of a magnetic field sensor 100 beyond that also the magnetic field sensor arrangement 120 , for example, as optional components, a substrate or a chip 180 and one or more magnetic field sensor elements 190 having. At the in 1a embodiment shown so has the sensor arrangement 120 at least two in 1a drawn magnetic field sensor elements 190-1 . 190-2 on. Depending on the technology used, the magnetic field sensor elements may be 190 For example, to magnetoresistive sensor elements (xMR sensor elements), to Hall sensor elements or other act on a magnetic influence responsive sensor elements such as magnetic diodes or magnetic transistors.

With respect to the present invention, it should be noted that it can be advantageously used in particular with such sensors or sensor elements which have a saturation behavior, ie. H. for example with xMR sensor elements.

In contrast, Hall probes, for example, have virtually no saturation. Since, however, the amplifiers connected downstream of the Hall probe always have a saturation behavior (because the amplifier saturates outside its modulation range), it may also be advantageous for Hall probes to use the magnetic bodies described here.

The magnetoresistive sensor elements include u. a. AMR sensor elements (AMR = anisotropic magneto resistance), giant magneto resistance (GMR) sensor elements, colossal magneto resistance CMR elements (CMR), and EMR (extraordinary magneto resistance) sensor elements = exceptional magnetoresistance), TMR sensor elements (TMR = tunnel magneto resistance) or spin valve sensor elements. Hall sensors can be horizontal or vertical Hall sensors.

Depending on the specific implementation, the magnetic field sensor arrangement 120 other components such as an evaluation circuit, a sensor circuit or a respective covering material for protecting the individual magnetic field sensor elements 190 include.

In some embodiments of a magnetic field sensor 100 as he is in 1a is shown, the magnetization M has, for example, the following symmetrical conditions with respect to a 1a shown symmetry line 195 at an x-coordinate (x = 0) with respect to the x-component M _{x of} the magnetization M and the y-component M _{y of} the magnetization M _x (x) = -M _x (-x) M _y (x) = M _y (x) (1).

This means that the x-component of the magnetization M _{x has} an odd symmetry with respect to the symmetry line 195 at x = 0 and the y-component M _y a straight symmetry with respect to the x-coordinate and the symmetry line 195 having. More generally, in some embodiments, the magnetization M includes a magnetic field sensor with respect to the associated magnetic body 110 an odd symmetry relationship with respect to one component and a straight symmetry relationship with respect to another component. More specifically, in some embodiments of a magnetic field sensor, the magnetization M of the magnetic body 110 with respect to a vector component, a straight symmetry relationship on and with respect to a vector component perpendicular to the vector component an odd symmetry relationship.

Before further embodiments of magnetic field sensors described and in connection with 1b to 13 It should be noted that objects, structures and components having identical or similar functional characteristics and features are indicated by identical reference numerals. Unless explicitly stated otherwise, the descriptions of objects, structures and components having similar or identical functional characteristics or features may be interchanged. In addition, in the further course of the present application, summary reference numbers for objects, structures, and components that appear multiple times in an embodiment are to be used in an identical or similar manner, unless features or properties of a particular object, structure or component explained or discussed. The use of summary reference numerals therefore enables a more compact and clearer description of the embodiments of the present invention.

1b shows a further embodiment of a magnetic field sensor 100 which is only marginal from the in 1a differs embodiment shown. The embodiment of an in 1b shown magnetic field sensor 100 includes a magnetic body 110 whose magnetization M in turn by the arrows 170 is displayed. Also in the in 1b In the illustrated embodiment, the magnetization M is in a substantial part of the magnetic body as by the direction of the arrows 170 shown inhomogeneous. More specifically, the magnetization M of the magnetic body 110 again the symmetry conditions described in connection with equation (1).

Unlike the in 1a shown embodiments, the magnetic body 110 of in 1b shown embodiment of a magnetic field sensor 100 a different course with respect to an upper edge. More specifically, at the in 1a shown embodiment, an upper edge of the magnetic body 110 bounded by a straight line, while in the magnetic body 110 in 1b the magnetic body over the in 1b shown area extends upward. Regardless, however, is in the in 1b shown magnetic body, the cross-sectional area 150 regarding the in 1b non-convex, since again the direct connecting line 160 whose endpoints are within the cross-sectional area 150 lie, yourself the recess 130 cuts and thus within the cross-sectional area 150 lies. In other words, regardless of the upper mold or the outer mold is the cross-sectional area 150 of the magnetic body 110 regardless of the exact shape of the outer, the upper or the lateral boundary surfaces of the magnetic body 110 not convex.

In addition, this differs in 1b embodiment shown with respect to the recess 130 , While at the in 1a shown embodiment, this has exhibited a polygonal cross-section is in the in 1b shown embodiment of the cross-section of the recess shown there elliptical.

In addition, the in 1a and 1b shown embodiments of a magnetic field sensor 100 barely. So can also at the in 1b shown embodiment with respect to a plane perpendicular to the in 1b shown cross-sectional plane of a cross section of the magnetic body 110 have other shapes, or have a similar shape or even the same shape.

In both embodiments, in 1a and 1b are shown is the magnetic field sensor arrangement 120 so with respect to the magnetic body 110 arranged, that in the ideal case also with a center of gravity or center of the magnetic field sensor arrangement 120 on the symmetry line 195 lies. In addition, ideally, the magnetic field sensor arrangement 120 with respect to the symmetry line 195 aligned such that an in 1a and 1b not shown connecting line of the two magnetic field sensor elements shown there 190 the symmetry line 195 cuts at a right angle. In other words, the magnetic field sensor arrangement 120 ideally arranged so that this the previously described symmetry of the magnetization M of the magnetic body 110 imitates or takes over. Of course, in the case of real implementations of a corresponding embodiment of a magnetic field sensor 100 to deviations with respect to the displacements in the x-direction and / or in the y-direction and with respect to a rotation about one of these axes or an axis perpendicular thereto come.

As will be explained in the further course of the present application, just enables the previously described inhomogeneous magnetization M of the magnetic body 110 in connection with its cross-sectional shape in some embodiments of a magnetic field sensor taking into account the technology used the magnetic field sensor elements 190 an improvement in an increase in the positional tolerance of the magnetic field sensor device 120 with respect to the magnetic body 110 , In other words, in some embodiments of a magnetic field sensor 100 a greater tolerance with respect to the exact arrangement of the magnetic field sensor arrangement 120 can be achieved without in a later operation of the embodiment of the magnetic field sensor 100 adverse effects in terms of measurement accuracy, functionality or other parameters must be taken into account, if necessary, by adversely affecting the magnetic body 110 positioned magnetic field sensor elements 190 can be caused.

Especially in the case of magnetoresistive magnetic field sensor elements 190 Thus, in some embodiments of a magnetic field sensor 100 be an advantage, a magnetic body 110 to implement, as it is included in the context of an embodiment. Thus, as will be explained later, optionally in some embodiments, an override of the relevant magnetoresistive sensor elements 190 be prevented or the positioning tolerance of the relevant sensor elements are increased, while for the actual measurement operation no or hardly negative consequences are to be feared.

2 shows a typical field of application of an embodiment of a magnetic field sensor 100 in connection with a determination of a rate of rotation or speed of a shaft. More specifically, in 2 an embodiment of a magnetic field sensor 100 shown, in addition to a running example of a permanent magnet magnet body 110 and the magnetic field sensor arrangement 120 also has a protective housing, which in the magnetic field sensor 100 is included. As previously explained, moreover, the magnetic field sensor arrangement 120 again two magnetic field sensor elements 190 on, which may be, for example, magnetoresistive magnetically-sensitive sensor elements. As explained above, in 2 the magnetic body 110 has been drawn in a simplified manner, without the previously explained characteristics of the magnetic body with respect to the magnetization and the cross-section with respect to the in 2 shown cross-sectional plane are shown. These features are in 2 merely for the sake of simplicity of illustration.

At a distance from a plane of the magnetic field sensor elements 190 that by an arrow 200 in 2 is marked and which is also referred to as a magnetic air gap or air gap, is a donor object 210 below the embodiment of the magnetic field sensor 100 attached, which is a gear, which is sometimes referred to as permeable encoder wheel. Other donor objects 210 Bolt wheels, pole wheels and other round or elliptical objects that are suitable, due to their choice of material and / or their topology one of the magnetic body 110 caused magnetic field in a movement of the encoder object 210 to influence or, where appropriate, in the case of a pole wheel itself to generate a magnetic flux density.

Depending on the specific implementation and application scenario, an embodiment of a magnetic field sensor 100 also in connection with other donor objects 210 be used. Thus, for example, a corresponding embodiment in connection with a pole rod, hole rod or rack as a donor object 210 be used, for example, to detect a linear movement or detectable. In many cases, the donor objects point 210 In this case, a periodic structure with respect to the magnetization, the topology or other features, so that in case of movement of the encoder objects 210 a periodic change of the magnetic field (including that of the magnetic body 110 ) is caused. The relevant donor objects 210 are often either part of or associated with a corresponding moving component.

In the case of a gear as a donor object 210 as it is in 2 is shown, this may for example be coupled to a shaft, that is about a crankshaft or a camshaft, or with a wheel. So is the donor object 210 moved, so in the case of in 2 Turned gear shown, as the arrow 220 indicates, there is a change in the magnetic field, which is the magnetic field sensor 100 can detect.

Thus, depending on the task in the field of use of an embodiment of a magnetic field sensor 100 For example, a movement of wheels can be detected by means of magnetic sensors, as may be desired, for example, in the context of an ABS system. Other embodiments of a magnetic field sensor 100 For example, they can be used in the field of engine control and monitoring, for example as crankshaft sensors or camshaft sensors. These include gears 210 in connection with small permanent magnets as magnetic body 110 at the back of the actual sensors or the magnetic field sensor arrangement 120 used. By moving or rotating the wheel then arises in the region of the magnetic field elements 190 a sinusoidal magnetic field, wherein in the case of magnetoresistive sensors (xMR sensors) while the component of the magnetic field in the chip level or substrate level is evaluated. At the same time, if appropriate, the direction of the rotational movement of the wheel can also be evaluated and recorded by a further sensor or by other technical measures.

In many applications, therefore, a small permanent magnet as a magnetic body 110 on a magnetic field sensor arrangement 120 attached, so that both can be arranged in front of a gear-shaped permeable disc, as shown in FIG 2 is shown schematically. If the disc is rotated, go through the teeth of the gear 210 the plane of the magnetic field sensor elements 190 in the distance of the magnetic air gap, thus producing a small field variation, that of the embodiment of the magnetic field sensor 100 can be detected and includes the information regarding the angular position and the rotational speed of the disc. Here, in many cases, the waveform of the magnetic field variation is nearly sinusoidal, and its amplitude drastically decreases as a function of a growing (magnetic) air gap.

In the case of a gear as a donor object 210 like this in 2 is shown, the amplitude of the waveform often decreases approximately exponentially, in proportion to a ratio of the magnetic gap and the so-called pitch (possibly multiplied by the factor 2 ^π ). Here, the so-called division is defined as the quotient of half the circumference of the gear divided by the number of teeth when they are distributed equidistantly over the circumference of the gear. The pitch thus represents half the period of the gear. For this reason, in some embodiments of a magnetic field sensor 100 and be advisable in various fields of application of the same, embodiments as close as possible to the donor object 190 to operate, for example, to avoid and prevent magnetic air gaps that are greater than about a tooth width. For example, increasing the magnetic gap from about a tooth width to about 150% of the tooth width may reduce a magnetic field amplitude by more than a factor of 5, depending on the exact circumstances. For example, the amplitude enters with exp (-2Pi * z / lambda), where lambda is the magnetic period, ie, lambda / 2 is a tooth width or a tooth width Gap width. If z = lamda / 2 to z = 1.5 · lamda / 2, then the amplitude changes accordingly by factor exp (-Pi) / exp (-Pi · 1.5) = 4.8.

In the case of magnetoresistive sensor elements, so for example GMR sensor elements 190 , It may happen that a corresponding magnet arrangement with respect to the magnetic field components in the plane of the substrate or the chip, the individual GMR sensor elements 190 overdriven. In such a case, it may happen that the or the affected magnetic field sensor elements 190 provide no usable or barely usable measurement signals.

So even if, for example, the gear 210 symmetrical to the chip of the magnetic field sensor arrangement 120 is arranged, so if, for example, a tooth center or a center of the gap of the gear 210 right in a 2 also drawn position (xx = 0), it can happen that the flux lines of the magnet diverge, causing unacceptably large Bx components on the two in 2 shown (magnetoresistive) magnetic field sensor elements 190 act. As already related to 1a and 1b Here, the position (x = 0) is explained by the symmetry line 195 defined, related to 2 to the exact position between the two in 2 shown magnetoresistive sensor elements 190 refers.

In such a case, both magnetoresistive sensor elements 190 driven into saturation and can no longer deliver a (usable) signal. In some applications, where an embodiment of a magnetic field sensor 100 is used, is a usual remanence of the magnetic body or back-bias magnets used 110 in a range of just over a Tesla (T). Typical gears as donor objects 210 have about 3 mm wide teeth and gaps, the gap depth also corresponds to about 3 mm. Of course, other dimensions of corresponding gears or other donor objects may occur in other application examples. Likewise, the corresponding embodiments of magnetic field sensors 100 not limited to these values. In the context of the present invention, it is pointed out that large magnetic fields can be achieved at the xMR element, for example with large magnets or even with large remanences or with a small demagnetization factor.

Depending on the specific application here are the magnetoresistive sensor elements 190 typically in the range of about 1 mm in front of the magnet or magnet body 110 arranged and the gear itself is about 1 to 4 mm in front of the magnetoresistive sensor elements 190 arranged so that the magnetic air gap is also in this area. The magnet or magnetic body 110 has in some applications, and thus in some embodiments, a magnetic field sensor 100 a cross section of 5 mm in the x-direction and 6 mm in the y-direction, wherein the magnetoresistive sensor elements 190 at the chip about 2.5 mm apart. In such a case, it may happen that the Bx component of the magnetic field strength on the right of the two magnetic field elements 190 is in the range of approximately 95 to 117 mT, the different values resulting as a function of the (magnetic) air gap. Correspondingly, in the case of a symmetrical design, the left sensor element is effective 190 Bx components in the range between -95 to -117 mT. Depending on the concrete implementation of the magnetic field sensor element 190 In particular, in the case of a GMR magnetic field sensor element, such a sensor element often has a linear drive range in the range of up to +/- 15 mT. Will such a GMR sensor element 190 Overdriven by the magnet, this does not work any more meaningfully and is no longer able to deliver meaningful measuring signals.

For other GMR sensor elements 190 It can happen that they saturate already at a magnetic flux density of about 10 mT. Thus, for example, magnetic field components or magnetic flux density components of more than 100 mT are at the location of the GMR sensor elements 190 before, so they are driven into saturation, so that small superimposed alternating magnetic fields, such as those of the donor object 210 can be caused, are no longer detectable. In such a case, therefore, it may be necessary to reduce the above-described magnetic flux density by a factor of 15.

If, for example, a saturation field strength of about 10 mT of a GMR sensor element causes only a modulation between 12 mT and 14 mT, in many cases the relevant GMR sensor element can no longer deliver a usable output signal so that the sensor as a whole may not more capable of rotating the encoder object 210 to detect.

As already explained above, the numerical data given above serve in particular for the illustration and are not to be understood as limiting. Thus, embodiments of magnetic field sensors 100 for a very wide selection of magnets or magnetic bodies 110 and for a very wide variety of different magnetic field sensor elements 190 be used. Likewise, in the case of corresponding application scenarios, embodiments with very many different donor objects 210 combined to form, for example, speed sensors or other magnet-based sensors.

3a and 3b show two further embodiments of magnetic field sensors 100 , More precisely, the two embodiments are each together with a donor object 210 represented, wherein it is the donor object 210 For example, to act a rack or a gear that simplifies the representation in 3a and in 3b is shown without curvature.

In the 3a and 3b shown embodiments of magnetic field sensors 100 thus each have a magnetic body 110 in turn, referring to the in 3a and 3b cross-sectional plane shown a non-convex cross-section with a recess 130 which, in the case of 3a and 3b shown embodiments is circular. Of course, it should be noted in this context that the term circular or elliptical is also applicable to corresponding sectors and sections of the relevant geometric figures, ie a circle or an ellipse.

At the in 3a and 3b illustrated embodiments of a magnetic field sensor 100 have the magnetic body 110 or the two back-bias magnets 110 again an inhomogeneous magnetization, as in both figures by the arrows 170 is shown. Depending on the specific embodiment of an embodiment, here again, the magnetic field sensor arrangement 120 optionally next to the chip or substrate 180 and the (magnetoresistive) magnetic field sensor elements 190 Thus, for example, GMR magnetic field sensor elements, a housing, which is also referred to as a package include.

The magnet or magnetic body 110 is at the in 3a and 3b illustrated embodiments formed as part of a ring and magnetized substantially radially, as the arrows 170 demonstrate. More specifically, here is the magnetic body 110 annular, but may in other embodiments of a magnetic field sensor 100 Other forms, such as a flat or erected ellipse, have. As already related to 1b explained it may be sufficient that the magnetic body 110 has an inner recess, thus the previously described magnetization of the magnetic body 110 can be made. Basically, in principle, any outer boundary curve can be provided. As previously discussed, in some embodiments of a magnetic field sensor 100 the inner recess may be circular, elliptical or polygonal. In other words, in different embodiments of a magnetic field sensor, the magnetic body may have a non-convex cross-section or a non-convex cross-sectional area with respect to a cross-sectional plane.

So shows 3a an embodiment in which the magnetic body 110 extends over 180 ° and is designed as a circular ring. In contrast, in the case of 3b illustrated embodiment of the magnetic body shown as a circular ring 110 over less than 180 °. Depending on the concrete implementation, the magnetic body can 110 extend over more than 180 °.

The sensor IC (IC = Integrated Circuit) or the magnetic field sensor arrangement 120 can be both "inside the magnet" as well as in the area of the recess 130 be pushed or relocated, as in 3a is shown. In the case of smaller magnets 110 or even in the case of a limited space, the magnet 110 also be placed on the back of the sensor IC, depending on the concrete implementation of an embodiment of a magnetic field sensor 100 a front and a bottom of the IC 120 in view of the described fixation can be used equally well in many cases.

In many applications, however, it may be advisable to use the GMR sensor elements 190 as close as possible to the gear or the encoder object 210 To move so that it may be advisable in such a case, the magnet 110 on that side of the chip 120 containing no components (eg the magnetic field sensor elements 190 ) to fix. In such a case, it may therefore be advisable to use the magnetic field sensor arrangement 120 in comparison to the representation of 3a and 3b rotated by 180 ° with respect to the magnetic body 110 to attach to this, exactly opposite to the representation in 3a and 3b , The magnetic field sensor elements 190 so so in terms of the substrate 180 and the donor object 210 are rotated by 180 °.

Depending on the concrete implementation, such a typical dimension can be used in the case of embodiments as described in US Pat 3a and 3b are shown, an outer diameter of about 9 mm and an inner diameter of about 5 mm, based on the shape of the magnetic body 110 , exhibit. A strength of the remanent magnetization may in turn, depending on the specific embodiment of an embodiment, be above about 500 mT or above about 1 mT.

The spacing between the two sensor elements 190 is in some embodiments, as far as a tooth or a tooth gap of a donor object 210 is great. In some embodiments or in some applications, this can be, for example, 2.5 mm for the distance between the two in 3a and 3b be shown outer sensor elements. Depending on the specific implementation, for example, a middle sensor element can be used for direction detection, which can optionally be arranged in the middle between the left and the right sensor element. However, in some applications, other distances between the sensor elements 190 meaningful. For example, other distances, such as 1.7 mm, can be used.

The surface of the chip 180 is in many cases in the range of about 0.5 mm to about 2 mm in front of the magnet 110 Distances of about 0.7 mm often represent a useful compromise, since on the one hand the magnet 110 as close to the chip as possible 180 and thus on the pole wheel 210 On the other hand, a thickness of mounting components (case bottom, conductor frame thickness, die attach thickness, and silicon thickness) should often be in the range of about 0.7 mm. A distance of the chip 180 from the donor object 210 , which is also referred to as the air gap, can be at least a few tenths of a mm, but should not exceed a distance of about four tooth spaces or four tooth gaps in some applications maximum, since at larger air gaps, the magnetic field signal amplitude decreases exponentially.

durchgeführt werden, wobei B die magnetische Induktion bzw. die magnetische Flussdichte als vektorielle Größe, μ₀ die Permeabilität des Vakuums, rot M die Rotation der (vektoriellen) Magnetisierung, grad_A r den Gradienten der Ortskoordinate bezüglich des Aufpunkts A und wobei r den Abstand zwischen dem Aufpunkt und dem Quellpunkt bezeichnet. Die Integration wird hierbei über den gesamten Raum durchgeführt, also nicht nur im Innern des Materials des Magnetkörpers 110, sondern auch über dessen Oberfläche, was durch die ”Integrationsgrenze” V in Gleichung (2) angedeutet ist. 4 shows a result of a numerical simulation of a magnetic field strength course and magnetic field lines, as in the case of a magnetic body 110 show how he related to 3a and the embodiment discussed there is described. A calculation of magnetic fields, such as those in 4 In many cases, however, it is anything but trivial, and in principle always results in the solution of the four Maxwell differential equations for electromagnetic fields. Although there are simplified forms for special cases, which can be solved in closed form, if necessary, but for the calculation of magnetic fields, magnetic flux densities and other processes and characteristics discussed in the present application, a numerical simulation is generally essential a 2-dimensional or 3-dimensional simulation using the finite element method. Corresponding simulations and calculations can take into account the corresponding boundary conditions, for example based on the equation

where B is the magnetic induction or magnetic flux density as the vectorial quantity, μ ₀ the permeability of the vacuum, red M the rotation of the (vectorial) magnetization, degrees _A r the gradient of the spatial coordinate with respect to the point A and where r is the distance between the receptor point and the source point. The integration is carried out over the entire space, not only inside the material of the magnetic body 110 but also across its surface, which is indicated by the "integration limit" V in equation (2).

Next to the magnetic body 110 is in 4 moreover, the schematic in 3a and 3b shown encoder object 210 shown. In addition to a variety of field lines 230 is beyond in 4 For some areas the respective magnetic flux density between 0.2 T to a maximum of 0.5 T is shown. Here, an arrow indicates 240 inside the illustration in 4 a decrease in magnetic field strength, as indicated by an arrow 250 is represented in the legend area.

4 Thus, thus represents the cross section of the magnetic body in the form of a circular ring which extends over 180 ° and is magnetized in the radial direction, as already in connection with 3a has been described. The gear as a donor object 210 is symmetrical to the magnet 110 positioned. Ideally, in this position, the Bx component of the magnetic flux density should be at the location of the magnetic field sensor elements 190 (not shown in 4 ) are as close to zero as possible, but at least within the linear drive range of a GMR sensor element, that is, for example, between about -15 mT and +15 mT.

This in 4 shown result of a numerical simulation based on the magnetic body 110 on a remanence of the magnetic body 110 of 1 T, which is homogeneous in magnitude over the entire magnetic body 110 extends. However, this does not apply to the direction of magnetization, which is inhomogeneous due to its radial shape.

In addition, in 4 horizontal lines between the end faces of the magnet 260 in the area of which the magnetic field strength Bx was evaluated as a function of the x-coordinate in the frame in the course shown in the following 5.

5 shows a total of eleven courses 270-1 to 270-11 , which determine the magnetic flux density Bx in Tesla (T) for the in 4 illustrated lines 260 play. The curves or gradients 270 correspond here in ascending order of their numbers, which are indicated behind the hyphen in the reference numeral, the y-positions y = -0.5 mm, -0.4 mm, -0.3 mm, -0.2 mm, - 0.1 mm, 0 mm, +0.1 mm, +0.2 mm, +0.3 mm, +0.4 mm and +0.5 mm.

The courses 270 show that due to the symmetry of the arrangement, the x-component of the magnetic flux density Bx as a function of the x-coordinate x for the case y = 0 (course 270-6 ) disappears almost identically and thus would represent an ideal position for the GMR sensor elements in principle. For example, if the magnetic field sensor elements 190 symmetrically distributed around x = 0 at a distance of 1.25 mm, ie at x-positions x = +/- 1.25 mm, y-positions are in the range between y = -0.1 mm and y = + 0.1 mm is quite suitable to ensure x-components of the magnetic field strength of less than 20 mT ( ^{| Bx |} <20 mT), as the gradients 270-5 . 270-6 . 270-7 for the y-positions y = -0.1 mm, 0 mm, +0.1 mm. The courses 270 in this case essentially have a mirror symmetry with respect to the point (x, Bx) = (0 m, 0 T). Compared to a simple cuboid magnet with a homogeneous magnetization throughout can thus by use of an embodiment of a magnetic field sensor 100 a reduction of the x component of the magnetic flux density Bx can be achieved, which can sometimes be even an order of magnitude.

6a and 6b show further embodiments of a magnetic field sensor 100 that the embodiments of 3a and 3b However, they differ from each other in that the magnetic bodies 110 magnetized in an azimuthal manner, as are the arrows 170 demonstrate. In this possibility of an embodiment of a magnetic field sensor 100 can be like in 6a shown the magnetic body 110 have an annular cross-section which extends over 180 °. Likewise he can like in 6b shown to have a cross section which extends over less than 180 °. The magnet 110 from the in 6b The embodiment shown can therefore be considered as "cut off in the radial direction", of course, other forms of the magnetic body 110 possible are. For example, magnetic bodies are also used 110 conceivable in which the end surfaces are cut off, for example in the x-direction or in the y-direction. As previously related to 1a . 1b . 3a and 3b has been explained, in this context, the outer shape of the magnetic body is less crucial. Therefore, of course, other directions which are skewed to the aforementioned directions are also "cut directions" of the magnetic body 110 possible.

Apart from the magnetization M, as indicated by the arrows 170 in 6a and 6b is shown, the embodiments of a magnetic field sensor shown in the figures differ 100 with respect to the other components not or hardly from the in 3a and 3b shown embodiments. For this reason, reference is made in particular with regard to the other components to the description of the same.

The magnetization of the magnetic body 110 as he is in 6a and 6b Thus, with respect to the x-component M _x (x) and the y-component M _y (x), the following symmetry conditions obey: M _x (x) = M _x (-x) M _y (x) = -M _y (-x) (3).

That is, in this case, the x component of the magnetization has a straight symmetry relation with respect to the line of symmetry 195 (x = 0), while the y-component of the magnetization in this case satisfies an odd symmetry relation with respect to x. Also in this case can be so in some Embodiments of a magnetic field sensor 100 It can be said that one of the two magnetization components M _x and M _y satisfies an odd symmetry relation with respect to x, while the other satisfies a straight symmetry relation with respect to the x coordinate.

7 FIG. 12 is an illustration of a result of a numerical simulation of a magnetic body. FIG 110 is based on an extent of more than 180 °, which is magnetized in the azimuthal direction, wherein the amount of magnetization on the volume of the magnetic body 110 is set as constant. In other words, the results are based on 7 shown simulation on an embodiment of a magnetic field sensor with a magnetic body 110 which is magnetized with a constant amount in the azimuthal direction, so that again due to the changing direction of the magnetization, this is inhomogeneous. This shows 7 again several field lines 230 as well as an arrow 240 inside the illustration, which corresponds to a direction along a decreasing magnetic flux density in the range between 0.5 T and 0.2 T, as indicated by the arrow 250 is displayed. In addition, in 7 again different lines 260 marked on which the in 8th and 9 reproduced gradients 270 Respectively. In other words, in the context of the following 8th and 9 a fitness of the different lines 260 with regard to a possible position for the magnetic field sensor elements 190 examined.

8th shows gradients 270-1 to 270-8 the x-component of the magnetic flux density Bx as a function of the x-coordinate for different y-coordinates. More precisely, this corresponds to the course 270-1 a y-coordinate of y = -0.8 mm, with the increasing number of the respective course, which is shown behind the hyphen within the reference numeral, the y-coordinate is reduced by 0.1 mm. Consequently, therefore, the course corresponds 270-2 a y-coordinate of y = -0.9 mm and, for example, the gradient 270-8 a y-coordinate of y = -1.5 mm. This shows 8th first, the relevant gradients 270 in a rough scale in a range between x = -2 mm to x = +2 mm, while in 9 an enlargement of the illustrated range of approximately x = 1.0 mm to x = 1.85 mm is shown.

Thus shows 8th First of all, almost all the curves or curves are independent of the selected y-parameter 270 in the range between about x = 1.3 mm and x = 1.4 mm have an x-component of the magnetic flux density Bx in the range between about +/- (20 mT-40 mT). At a shorter distance from the magnet or magnet body 110 , so for larger y-values, the gradients run 270 in the range at about x = +/- 1.4 mm through the line B _x = 0, so this is a very suitable location for magnetoresistive sensor elements 190 , so for example GMR sensor elements 190 , can represent.

Accordingly, in 9 the area of in 8th shown courses enlarged in the range by x = 1.4 mm. So shows 9 for example, that in particular the gradients 270-2 . 270-3 and 270-4 , which correspond to the y-parameters y = -0.9 mm, -1.0 mm and -1.1 mm, intersect the line "Bx = 0" in the area around x = 1.4 mm, as the detail image in FIG 9 shows.

Before related to 10a and 10b further embodiments of a magnetic field sensor 100 will first be briefly outlined a method by which the inhomogeneous magnetizations explained in the preceding figures can be realized. In the case of the magnetic body 110 , which have a radial or quasi-radial magnetization, as they so for example in 1a . 1b . 3a and 3b can be shown in the recess 130 the respective magnetic body, a correspondingly shaped counterpart, for example made of iron, are used, which fits seamlessly to the correspondingly shaped surface of the magnetic body 110 attaches. Likewise, from the outside, a correspondingly shaped iron part can be placed on the outer surface, so that the later magnetic body 110 is covered from outside and inside by appropriate iron parts. Subsequently, the two iron parts can be connected by an almost arbitrarily shaped bracket. Then, a winding can be wound around the bracket, which is then energized to generate the magnetization.

In the case of a magnetic body having an azimuthal magnetization, a circular conductor may enter the interior of the magnet, that is, the recess 130 of the magnetic body 110 , and a circular conductor on the outside can ideally be seamlessly attached to the magnet body 110 be nestled. Now, a current in the inner metallic conductor from the respectively in 6a respectively. 6b drawn drawing plane out and sent in the outer conductor a corresponding current in the plane of the drawing, so the magnetization in question in the magnet 110 aligned in azimuthal direction counterclockwise.

10a and 10b show further embodiments of a magnetic field sensor 300 , which differs from the previously shown embodiments according to the magnetic field sensors 100 differs in that the embodiments shown here a first magnetic body 310 and a second magnetic body 320 have, wherein the first magnetic body 310 has a first magnetization direction, which in 10a and 10b each by an arrow 330 is marked. The second magnetic body 320 also has a magnetization direction which is in 10a and 10b by an arrow 340 is registered. The two magnetization directions of the two magnetic bodies 310 . 320 are different in terms of their magnetization directions and include an angle with each other.

Regarding a symmetry line 195 , which in turn corresponds to an x-coordinate of x = 0, close the magnetization directions (arrows 330 . 340 ) of the two magnetic bodies 310 . 320 with the symmetry line 195 in each case an angle, the amount of the two magnetic body 310 . 320 is identical or different from each other by no more than typically 20 °, 10 °, 5 ° or 2 °, depending on the specific embodiment of a corresponding embodiment of a magnetic field sensor 300 and its specifications. In other words, the two magnetic bodies 310 . 320 related to the symmetry line 195 in many embodiments of a magnetic field sensor 300 a symmetric magnetization with respect to the symmetry line 195 on.

In addition, the in 10a and 10b illustrated embodiments of a magnetic field sensor 300 again a magnetic field sensor arrangement 120 with a substrate 180 and one or more magnetic field sensor elements 190 on. As already mentioned in connection with the previously explained embodiments of a magnetic field sensor 100 has been described, the magnetic field sensor arrangement, a single magnetic field sensor element 190 or several corresponding magnetic field sensor elements 190 exhibit. At the in 10a and 10b illustrated embodiments includes the magnetic field sensor arrangement 120 two each, substantially symmetrical to the line of symmetry 195 arranged magnetic field sensor elements 190 which are, for example, the previously described possible magnetic field sensor element technologies. Thus, in this case too, the magnetic field sensor elements Hall can comprise sensor elements, magnetoresistive sensor elements or other corresponding magnetic field sensor elements.

In this connection, it should be pointed out that due to the above-described problem of positioning tolerance in the case of real implementations of embodiments of magnetic field sensors 100 . 300 the previously described symmetry properties of the various components with respect to the symmetry line 195 may deviate only within a predetermined tolerance limit, so for example within a depending on the application positioning tolerance in the lateral direction or in the vertical direction. In other words, the symmetry line refers 195 on a center, for example, two magnetic field sensor elements 190 on the substrate 180 the magnetic field sensor arrangement 120 , They both magnetic body 310 . 320 , which together form the back-bias magnets, may optionally deviate from their respective position within predetermined positioning tolerances. In many cases, the corresponding positioning tolerances are application-specific and, for example, certainly depend on the technology of the magnetic field sensor elements used 190 affected.

In 10a and 10b is in turn the donor object 210 drawn, which in turn may be, for example, a rack, a pole rod, a perforated rod, a gear, a pinwheel or a flywheel. Depending on the specific application, other donor objects can also be used 210 be used depending on the specific design in many cases, where appropriate, the relevant donor object 210 such that it is capable of producing a modulation, such as a periodic or sinusoidal modulation, of a magnetic field, which (among other things) in this case of the first often executed as a permanent magnet magnetic body 310 and the second magnetic body 320 the back-bias magnet arrangement or the back-bias magnet is generated.

Relative to the symmetry line 195 are in many embodiments of a magnetic field sensor 300 the first magnetic body 310 and the second magnetic body 320 formed or arranged symmetrically to this. In addition to the previously mentioned possibility, a definition of the symmetry line 195 with respect to a center position of magnetic field sensor elements 190 If these are present in a corresponding number and arrangement, of course, there is also the possibility of the symmetry line 195 with respect to a midpoint or other corresponding line or mark with respect to the substrate 180 define. Taking into account the positioning deviations or positioning tolerances of the individual magnet bodies caused, for example, by manufacturing tolerances 310 . 320 each have a symmetrical mounting position with respect to the symmetry line 195 on.

Here, as explained above, depending on the specific definition of the location of the symmetry line 195 the two magnetic bodies 310 . 320 and / or the locations of the individual magnetic field sensor elements 190 corresponding installation tolerances or positioning tolerances with respect to the symmetry line 195 exhibit. In other words, for example, a center of gravity of the two magnetic body 310 . 320 at a distance from the line of symmetry 195 are removed, which is typically smaller than a corresponding positioning tolerance.

The same applies not only in the x-direction, but also in the perpendicular y-direction, as in 10a and 10b is drawn. Depending on the production technology used, in particular the fastening technique of the magnetic body with respect to the magnetic field sensor arrangement 120 , so in the x-direction and / or y-direction and in the in 10a and 10b not shown z-direction positioning errors occur that are in the range of a few 100 microns to the range of a few millimeters. In other words, the corresponding positioning tolerances may be in the range up to a few 100 μm or in the range up to a few millimeters, that is in the range up to about 1000 μm or in the range up to about 2 mm.

Relative to the positioning of the individual magnetic field sensor elements 190 relative to a respective magnetic body of the two magnetic body 310 . 320 is true that in many embodiments of a corresponding magnetic field sensor 300 , a symmetrical arrangement of the magnetic field sensor elements 190 and / or the magnetic body 310 . 320 provided the magnetic field sensor elements 190 each have x-coordinates which are in the range of the x-coordinates of one of the two magnetic bodies 310 . 320 lie. In other words, in such embodiments of a magnetic field sensor 300 the associated magnetic field sensor elements 190 above or below the relevant magnetic body 310 . 320 ,

With regard to the angle, the direction of magnetization of each magnet body 310 . 320 with the symmetry line 195 or also in 10a and 10b drawn, perpendicular line 350 includes, applies to many embodiments of a magnetic field sensor 300 in that an angle of magnetization of one of the two magnetic bodies 310 with the symmetry line 195 in many cases an angle between 10 ° and 80 ° includes. In many embodiments of a magnetic field sensor 300 runs the symmetry line 195 perpendicular to a major surface or surface of the substrate 180 on which the magnetic field sensor elements 190 are arranged. Accordingly, the respective magnetizations close with respect to the line 350 also in terms of magnitude an angle in the range between 10 ° and 80 °. In addition, in the case of a symmetrical design of the two magnetic body close 310 . 320 the respective magnetizations in each case an angle to one another, the amount is in the range between 20 ° and 160 °. Depending on the specific field of application, in embodiments of a magnetic field sensor 300 Other angular ranges occur, which will be explained in more detail in the further course of the present application in the context of numerical simulations.

In the 10a and 10b illustrated embodiments of a magnetic field sensor 300 differ essentially in terms of the arrangement of the two magnetic body 310 . 320 to each other. While at the in 10a embodiment shown, the two magnetic body 310 . 320 directly adjacent to each other, for example, by being fixed to each other by a bond are in the in 10b embodiment shown, the two magnetic body 310 . 320 separated by a corresponding gap. The gap between the two magnetic bodies 310 . 320 may for example be filled with a magnetic or non-magnetic material, for example, the attachment or the overall structure of the embodiment of a magnetic field sensor 300 serves. For example, partially or completely between the two magnetic bodies 310 . 320 a plastic fastening are introduced, to which the two magnetic body 310 . 320 glued or otherwise secured. Alternatively or additionally, in the context of the overall assembly of the magnetic field sensor arrangement 120 the two magnetic bodies 310 . 320 be fixed by casting together, so that in the gap between the two magnetic bodies 310 . 320 at least partially encapsulating material passes.

As already related to the in 3a . 3b shown embodiment of a magnetic field sensor 100 can also be stated in embodiments of a magnetic field sensor 300 the magnetic field sensor arrangement 120 with her substrate 180 and the magnetic field sensor elements 190 in turn comprise an assembly (package).

In principle, it is of course also possible that between the two magnetic bodies 310 . 320 like this in 10b is shown, no solid material is inserted, but rather that the two magnetic body 310 . 320 with the magnetic field sensor arrangement 120 directly connected or glued. In one Such a case may optionally include introducing a material between the two magnetic bodies 310 . 320 omitted.

At the in 10a and 10b shown embodiments of a magnetic field sensor 300 So are two individual magnets as a magnetic body 310 . 320 to a new magnet or back-bias magnet so assembled that in turn apply to the magnetization components of the overall arrangement of the two magnetic body given in Symmetry conditions (1). Again, this corresponds in turn based on the overall arrangement of the two magnetic body 310 . 320 an inhomogeneous (total) magnetization. More precisely, this corresponds to an inhomogeneously magnetized total magnet, which consists in each case about half of the volume of two homogeneously magnetized magnetic bodies or two homogeneous regions. In 10a and 10b In the exemplary embodiments of a magnetic field sensor shown there, a second cuboid with an oblique magnetization is added as a most easily simplistic example.

Depending on the specific implementation, for example, the two magnetic body 310 . 320 be formed as two block magnets with a width of about 2 mm and a height of about 5 mm and glued back to back together. Both individual magnetic bodies 310 . 320 are in this case homogeneously magnetized, again depending on the specific embodiment, for example, a remanence of about Brem = 1 T prevails in the relevant direction, by the magnetization or the arrows 330 . 340 is shown. For example, in some embodiments, the direction of magnetization may be at an angle of +/- 50 ° with respect to the line of symmetry 195 , ie the vertical direction.

Some embodiments of a magnetic field sensor 300 that made the arrangements 10a and 10b provide very good results with regard to a combination with a magnetic field sensor arrangement with magnetoresistive sensor elements. In addition, these can often be made particularly easy, since the relevant magnetic body 310 . 320 as homogeneous magnetized individual magnets are relatively easy to produce.

As already related to the in 3a and 3b shown embodiments of a magnetic field sensor 300 , it may also be useful in this case, depending on the specific implementation, the magnetic field sensor arrangement 120 concerning the line 350 to implement mirrored, so that the magnetic field sensor elements 190 in the context of the finished magnetic field sensor the encoder object 210 are facing.

As in 10b shown schematically, the two magnetic body 310 . 320 be spaced apart by a non-magnetic gap. Depending on the specific implementation, this may be useful, for example, for mounting, since a suitable distance may be formed as an adhesive surface. In addition, it is also possible by introducing such a non-magnetic gap, an interaction of the two magnetic body 310 . 320 so that they can not overlap or influence each other so much.

Some embodiments of a magnetic field sensor 300 based in terms of by the two magnetic body 310 . 320 formed back-bias magnets on the idea that when the field lines of a magnet diverge, a second magnet can be placed next to it, which picks up the unwanted components of the first magnet.

11 shows a result of a numerical simulation of a magnetic flux density distribution of an embodiment of a magnetic field sensor 300 as he is in 10a is shown schematically. 11 shows next to a number of field lines 230 one in the area of the two magnetic bodies 310 . 320 calculated magnetic flux density distribution in a range between 0.2 and 0.5 T. As already stated in 10a is shown schematically, in this case have the two magnetic body 310 . 320 a magnetization with a magnetic remanence of Brem = 1 T, which is indicated by the arrows 330 . 340 in 11 also indicated. The resulting magnetic flux density distribution is in accordance with the right in 11 represented gray scale distribution, wherein at a contact surface of the two magnetic body 310 . 320 a maximum magnetic flux density prevails, while outside the two magnetic body 310 . 320 a significantly smaller magnetic flux density prevails.

In addition, shows 11 a line 260 , regarding in 12a an x-component of the magnetic flux density Bx is shown in a range of x = -2 mm to x = +2 mm for a y-coordinate of y = -1 mm. Here are the in 11 shown numerical simulation two cuboid magnets or magnetic body 310 . 320 each with a homogeneous magnetization, but with the vertical downwards y-axis or by-axis an angle of +/- 35 °. Consequently, lies between the two magnetizations of the two magnetic body 310 . 320 and the horizontal in terms of magnitude an angle of 55 ° before.

As previously briefly indicated 12a the x-component Bx as a function of the x-coordinate for a y-value of y = -1 mm, which is the in 11 shown line 260 equivalent. In 12b Then, the corresponding x-components of the magnetic flux density Bx are plotted as a function of the x-coordinate for a y-value of y = -1.5 mm 11 is not shown.

For the case of a y-value y = -1 mm shows 12a the x-component of the magnetic flux density Bx in the range of x = -2 mm to x = +2 mm for different angles of magnetization of the two magnetic bodies 310 . 320 , In this case, the simulations are based on the previously explained symmetry of the magnetization directions of the two magnetic bodies 310 . 320 on the basis of which, in terms of amount, in each case with the horizontal, those in the context of the reference signs of the individual courses 270 include reproduced angle. The history 270-70 based on an angle of the magnetizations of the two magnetic bodies 310 . 320 with the horizontal of 70 °, so that for this simulation or calculation, the magnetizations of the two magnetic bodies with the line of symmetry 195 out 10a enclose an angle of 20 °. Accordingly, the course corresponds 270-55 the in 11 shown case of an angle between the perpendicular symmetry line 195 of 35 ° or an angle of magnetization with the horizontal of 55 °.

12b shows accordingly several courses 270 for angles between 40 ° and 70 ° representing the magnetizations of the two magnetic bodies 310 . 320 to include with the horizontal. Consequently, the in 12b illustrated courses 270-40 to 270-70 Angles of the magnetizations of the magnetic bodies 310 . 320 regarding the in 10a shown vertical line of symmetry 195 between 20 ° (course 270-70 ) and 50 ° (course 270-40 ). Especially at the in 12b shown case of a vertical distance of the magnetic field sensor elements 190 from the lower edge of the two magnetic bodies 310 . 320 of 1.5 mm (y = -1.5 mm, the magnet ends at y = 0 mm) it can be seen that the condition ^{| Bx |} <20 mT can be satisfied for wide ranges of the x-coordinates in the case y = -1.5 mm. As this is also true for the 12a In the case shown in the range of further x-coordinates can be met, there is thus in particular the possibility of using an embodiment of a magnetic field sensor 300 as he is schematic example in 10a or 10b is shown, magnetoresistive magnetic field sensor elements 190 to implement without the magnetic field sensor elements 190 through the relevant x-components of the by the magnetic body 310 . 320 caused magnetic fields are driven into saturation.

In other words, with the aid of an exemplary embodiment of a magnetic field sensor 300 In a comparatively wide range of x-coordinates and y-coordinates, a horizontal component of a magnetic flux density (for example, x-component) Bx which does not cause saturation of magnetoresistive sensor elements is generated 190 leads. In the case of GMR sensor elements thus show so 12a and 12b in that a condition ^{| Bx |.} valid for many GMR sensor elements <20 mT can be fulfilled for wide ranges of x-coordinates and y-coordinates.

In addition, show 12a and 12b that by a variation of the direction of the two magnetic body 310 . 320 the respective areas can be shifted so that different distances between magnetic field sensor elements 190 can be realized. Thus, it is possible to use various embodiments of magnetic field sensors 300 to create the different distances of the magnetic field sensor elements 190 to each other.

In summary, it can be said that through the use of corresponding embodiments of magnetic field sensors 300 with (at least) two magnetic bodies 310 . 320 , Magnetic systems can be constructed so that the corresponding magnetic field sensor elements 190 even in the case of sensitive magnetoresistive sensor elements, so about GMR sensor elements are not driven into saturation.

13 shows a further embodiment of a magnetic field sensor 300 extending from the in 10a and 10b illustrated embodiments of a magnetic field sensor 300 essentially differs in that the two magnetic body 310 . 320 no longer have a skewed magnetization with respect to their geometric shape, but rather that they are perpendicularly magnetized relative to an end face. In this case, the two magnetic bodies 310 . 320 no longer arranged parallel with respect to their side surfaces, as is the case in the embodiments in FIG 10a and 10b was. Rather, to achieve the two different magnetization directions of the two magnetic body 310 . 320 these now in turn at a corresponding angle with respect to the line of symmetry 195 or the perpendicular line 350 arranged.

Thus, also in this case, the first magnetic body 310 and the second magnetic body 320 a first magnetization direction and a second magnetization direction, which differ. Thus, even in the case of such an arrangement of magnetic bodies 310 . 320 an inhomogeneous total magnetization by superimposing the magnetic fields of the two (homogeneously magnetized) magnetic body 310 . 320 achieved.

In other words, can be appropriate arrangements of magnetic bodies 310 . 320 Find accordingly with different magnetization directions in that instead of two obliquely or obliquely magnetized magnet body 310 . 320 two parallelepiped magnets or magnetic bodies are used which are magnetized in the longitudinal direction and are tilted, implemented and installed at a corresponding angle, for example +/- 35 ° relative to the y-axis. In other words, it is for embodiments of magnetic field sensors 300 irrelevant whether the two different magnetization directions of the two magnetic body 310 . 320 as indicated by the arrows 330 and 340 can be generated by the fact that magnetic bodies are used with different, oblique magnetization or whether magnetic body are used with identical magnetization, but in the context of the respective embodiment of the magnetic field sensor 300 are installed according to diagonally or with appropriate mounting directions.

Regarding the more precise installation positions of each magnet body 310 . 320 in one embodiment, as in 13 Of course, the previous explanations also apply, in which case the only difference is that the respective magnetic bodies 310 . 320 now turned accordingly.

In fact, there is an exact shape of each magnet body 310 . 320 very big freedoms. In principle, all imaginable forms of corresponding magnetic bodies can be used. For example, cuboid, cylindrical or other, for example tapered, magnetic body are conceivable. In addition, of course, in the context of the two magnetic body 310 . 320 not only homogeneously magnetized magnetic body are used, as was implicitly assumed in the embodiments described above, but it can of course be used inhomogeneously magnetized magnetic body. In other words, the magnetic bodies 310 . 320 also be inhomogeneous with respect to their magnetization directions and / or their magnetization strength.

Embodiments of magnetic fields 100 . 300 thus allow horizontal magnetic field components or horizontal components of the magnetic flux density by using an inhomogeneous magnetization of the magnetic body 110 or the back-bias magnet, the at least the two magnetic body 310 . 320 includes reducing so far that, for example, magnetoresistive sensors (xMR sensors) are no longer overdriven, that is driven into saturation. As explained above, embodiments of magnetic field sensors are possible 100 Therefore, in the context of the present application, somewhat loosely described as the Bx field of the back-bias magnet flux density component by the described inhomogeneous magnetizations so far to reduce that a corresponding override of the sensors or sensor elements does not occur.

Embodiments of the present invention in the form of magnetic field sensors 100 . 300 achieve a desired field line course, among other things, characterized in that by an inhomogeneous magnetization of the magnetic body 110 . 310 . 320 the respective components of the resulting magnetic flux density are limited. Accordingly, embodiments of magnetic field sensors 100 . 300 possibly also be produced without an implementation of magnetic bodies with extremely filigree formations or recesses, or it may be corresponding embodiments of magnetic field sensors 100 . 300 where appropriate, also be developed and built without the use of highly permeable parts as magnetic lenses for field line deformation. Embodiments of corresponding magnetic field sensors 100 . 300 can so using appropriate back-bias magnet circuits in the form of the magnetic body 110 . 310 . 320 be used among other things for magnetoresistive speed sensors. Application examples of corresponding embodiments of magnetic field sensors can be found in the automotive sector as well as in other sectors such as mechanical engineering, plant construction, aircraft construction, shipbuilding and other areas of technology in which magnetic fields must be detected.

14A shows a cross-sectional view of another embodiment of an inhomogeneous magnet 400 which is suitable as a back-bias magnet, as discussed above in combination with the magnetic sensor 120 should be used. The inhomogeneous magnet 400 is a bit like the magnet 110 or the magnetic body 310 . 320 , It should be noted, however, that the inhomogeneous magnet 400 does not comprise two distinct magnetic bodies of substantially homogeneous magnetization joined together or meeting at a certain angle resulting in the degree of inhomogeneous magnetization described above. On the contrary, the inhomogeneous magnet 400 malleable as a unitary element but possesses the inhomogeneous magnetization as indicated by the arrows 14-1 . 14-2 . 14-3 is indicated, the one magnetization direction in a certain position within the cross-sectional view of the magnet 400 represent. The cross-sectional view of 14A is shown along the xz plane, ie a B _x component of the magnetization is indicated in the lower part of the figure, while a B _y component of the magnetization is indicated on the left side of the figure. It is understood that this choice serves illustrative purposes and the magnet 400 instead may have inhomogeneous magnetization within other cross sections. The magnetization in 14A is symmetrical to a symmetry line 14-0 imaged as shown by the dashed line.

Although the inhomogeneous magnetization of 14A as completely symmetrical to the symmetry line 14-0 is illustrated, it will be appreciated that for a true cross section of the inhomogeneous magnet 400 different effects can break a symmetry of the magnetization in cross section, so that this magnetization is no longer completely symmetrical. Such effects can be areas that affect the magnet 400 limit (magnetic) impurities within the magnet 400 and / or magnetic materials that are sufficiently close to the magnet, but are not limited thereto. For the present disclosure, magnetization within a cross section should also be considered symmetrical if only 90%, 80% or 50% of the cross sectional area is in fact symmetric magnetization with respect to the line of symmetry 14-0 within the cross section.

For this revelation of magnetization (as in 14 shown) it is to be understood that this line of symmetry 14-0 a mirror-symmetric magnetization of the magnet 400 can specify. Without limitation, the symmetry line 14-0 as seen in the cross section of 14A is indicated, a higher order symmetry of the magnet 400 indicate, for example, a triple or higher order of symmetry. An object of higher order of symmetry includes more than one cross-sectional plane to which or in which some properties of the object are symmetric, such as a magnetization of the object or the crystal structure of a mineral. Thus, for a higher order symmetry line, there may be more than one cross section to or in which the property of the symmetric object is symmetric, while the multiple cross sections actually intersect at the higher order symmetry line.

It will further be appreciated that the line of symmetry 14-0 of the magnet 400 as they are in 14A in fact, be a rotational symmetry axis or an ellipsoidal symmetry axis. Experts will thus easily recognize that the back-bias magnet 400 can also be rotationally symmetric. Therefore, any disclosure that uses the inhomogeneous (back-bias) magnet such as the back-bias magnet 400 relates to objects of rotational symmetry. A rotational symmetry or ellipsoidal symmetry of the magnet may be of interest, depending on the circumstances. It is understood that an ellipsoidal symmetry axis of rotational symmetry having not only a radius but a rotation between a first and a second radius gives an overall ellipsoidal characteristic when in a cross section substantially perpendicular to the line of symmetry 14-0 considered corresponds.

As before, a magnetization with higher order symmetry, rotational symmetry, or ellipsoidal symmetry within a cross section should still be considered symmetric to higher order symmetry, rotational symmetry, or ellipsoid symmetry, even though only 90%, 80%, or 50% of the cross sectional area in the Did a magnetization of higher symmetry with respect to the symmetry line 14-0 exhibit. Similarly, the magnetization of the back-bias magnet is considered to be of higher order symmetry, rotational symmetry or ellipsoidal symmetry, even though only 90%, 80% or 50% of the volume of the magnet is magnetization of higher symmetry on the symmetry line 14-0 exhibit.

It should be noted that in a lower portion of the cross-sectional view (lower z values or z values equal to zero) magnetization of the magnet 400 Almost completely aligned along the z-axis. However, as the z-coordinate increases, the magnetization becomes increasingly inhomogeneous. That is, the higher the z-coordinate, the larger is an angle α between the z-direction and the orientation of the magnetization, as shown 14A when comparing the angle α is visible for increasing z-coordinates. Obviously, the magnetization is parallel along the axis of symmetry 140-0 aligned. Parallel to the symmetry line 14-0 but not on the line of symmetry, which would be a given x-coordinate in the z-direction, the angle α will increase significantly with increasing z-values. Such behavior can be described as monotonous, more precisely monotonically increasing.

Along a path perpendicular to the line of symmetry 14-0 a nonmonotonic behavior of the angle α can occur. That is, perpendicular to the line of symmetry 14-0 the angle α may initially decrease until the symmetry line 14-0 is reached, and rise again after the line of symmetry has passed. A course perpendicular to the symmetry line 14-0 would in 14A corresponding to the course in the x direction along the cross section for a given z value.

Similarly, the angle α of the magnetization in the course away from the line of symmetry in a horizontal direction (constant z-coordinate) for those parts of the magnet 400 too, which is not in the lower part of 14 are. The increasingly inhomogeneous magnetization is best seen when the angle α for arrows 14-1 . 14-2 and 14-3 is compared. An alternative possibility is the increasingly inhomogeneous magnetization along the z-direction (except along the line of symmetry 14-0 ) is to call them increasingly divergent. It should be understood that the cross-sectional distribution of the magnetization is for illustrative purposes and is not intended to limit the teachings of the present disclosure in any way.

Those skilled in the art will recognize that it is possible to fabricate a total magnet using a molding process that has inhomogeneous magnetization as described in US Pat 14A is shown. According to a first variant of such a molding process and similar to the discussion with respect to a preparation of radially magnetized magnets (each 3a . 3b ), the molding tool may be configured to generate a spatially varying magnetic flux density in the interior of the tool while a magnetizable molding material is injected and / or melted inside the molding tool. The spatially varying magnetic flux density in the interior of the mold is projected onto the magnetizable mold material and is to continue as soon as the molding process is complete, which is the total magnet 400 with inhomogeneous magnetization as a unitary element. In fact, the mold, the magnetizable mold material, and the spatially varying magnetic flux density within the tool can be selected to virtually any desired spatially varying magnetic flux density within the magnet 400 to reach when the molding process is completed.

It should be noted that an alternative molding process can be used to produce a total magnet having inhomogeneous magnetization, such as that shown in FIG 14A is shown. The mold can be filled with a conventional magnetizable or magnetic molding material and can cure in the desired shape of the inhomogeneous magnet to be produced. It is conceivable that during the hardening of the inhomogeneous magnet to be produced, no external magnetic field or a homogeneous external magnetic field is applied. This would lead to a magnet showing a more or less vanishing magnetization or a uniform magnetization. Once the magnetizable mold material has cured, an inhomogeneous external magnetic field can be applied to the cured mold material in the shape of the inhomogeneous magnet to be generated. It may be advantageous to apply the inhomogeneous magnetic field to the cured molding material while it is still in the mold. Such an approach can be beneficial if the inhomogeneous magnet 400 the mold leaves. An exchange time per unit needed in the mold can be increased with this approach. However, depending on the circumstances, it may be of interest to move the cured molding material into the shape of the inhomogeneous magnet into a magnetizing device that provides a sufficiently large inhomogeneous magnetic field to project it onto the magnetizable cured molding material in the form of the inhomogeneous magnet; This will produce the inhomogeneous magnet 400 completed in accordance with the present disclosure.

14B illustrates an exemplary form of the inhomogeneous magnet 400 according to the present disclosure. It may be convenient to the magnet 400 to provide brick-like, ie cuboid or in a slightly conical brick-like shape, as in 14B is shown. Such a shape may be of interest to known back-bias magnets with the inhomogeneous magnet 400 which is malleable to replace. A back-biased magnet supplier would usually use the back-biased magnet 400 and the sensor arrangement 120 (not shown) to create a module which is sold to a customer of the supplier, the module now comprising communication means from the sensor elements to an ECU, which are not discussed in detail with respect to this disclosure.

Without restriction, the sensor can also 100 (please refer 2 ), which is built by the automotive supplier, have a brick-like shape, as in 14B while the communication means from the sensor elements to the ECU are not shown. The sensor 100 may also have a rotationally symmetric or ellipsoidal-symmetrical shape. The rotationally symmetric or ellipsoid-symmetric sensor 100 may optionally take a truncated cone shape depending on the circumstances. Professionals will realize that an ellipsoidal shape of the sensor 100 may have the advantage that a rotation of the sensor 100 easily at installation only by any housing provided in the vehicle and corresponding to the ellipsoidal shape and thereby the sensor 100 arranges in a designated position can be prevented.

If the sensor 100 however, would be rotationally symmetric, a groove or notch could be provided on a surface of the sensor to provide an array of the sensor as achievable for the ellipsoidal shape. It may be advantageous to have the groove or notch removed from the magnetic field sensor assembly 120 to arrange the groove or notch magnetic field distribution in the vicinity of the magnetic field sensor assembly 120 not affected (not shown).

14C illustrates such a shape for the sensor 100 that a groove 101 away from the detection elements 190 includes. Such a notch may be provided with a projection in the housing for the sensor 100 mate, which is provided in a device using the sensor, such as a vehicle. As an alternative to the notch may be a frusto-conical sensor 100 non-parallel top and bottom surfaces include (more generally non-parallel non-circumferential surfaces) so that the sensor 100 only mates with a corresponding housing in a defined circumferential position. Other ways of positioning the rotationally symmetric sensor 100 within the corresponding housing will be apparent to those skilled in the art and therefore will not be discussed further here.

14C discloses another alternative of implementing the sensor 100 , In the implementation of 2 are the sensor elements 190 arranged in a sensor assembly containing the magnetic field sensor assembly 120 forms. Unlike in 2 includes the sensor 100 from 14C not the assembly containing the magnetic field sensor assembly 120 forms. One will find that a packaging / molding step is through the implementation of the sensor 100 with a nude chip 195 that the sensor elements 190 carries, without the assembly can be saved. Such an implementation of the sensor 100 becomes cheaper for the (automotive) supplier. In exchange, care must be taken that the sensor elements 190 and consequently the nude chip 195 spatially related to the back-bias magnet 400 are arranged correctly. While for their correct alignment in previous implementations of the sensor 100 has been taken care of by the chipmaker, the correct alignment is now a task that falls to the supplier.

Although between the nude chip 195 and the back-bias magnet 400 in 14C is a spatial distance, it will be recognized that the inhomogeneous magnetization of the back-bias magnet 400 can be designed so that the nude chip 195 directly on the back bias magnet 400 can be arranged. Professionals will realize that the nude chip 195 typically requires some coupling means to make electrical connection from the naked chip 195 to create an outside of it. Such means of providing electrical communication may take the form of a leadframe, but are not limited thereto. Persons skilled in the art will recognize other options for providing electrical communication that do not limit the teachings of the present disclosure and, therefore, will not be described in further detail. For the remainder of the present disclosure, the naked chip is intended 195 as optional, the coupling agents are considered to be comprehensive. In various embodiments, the design of the back-bias magnet facilitates 400 with the nude chip 195 the correct spatial arrangement of the naked chip 195 in terms of the back-bias magnet 400 ,

14D illustrates another alternative of implementing the sensor 100 who cares the back-bias magnet 400 includes. In fact, it is used to implement 14D the inhomogeneous magnet 400 also as the housing of the sensor 100 , By properly controlling both a spatial distribution of the inhomogeneous magnetization of the magnet 400 as well as the positioning of the naked chip 195 Relative to the inhomogeneous magnetization, the assembly that houses the sensing elements 190 covered, and the other molding material that provides the housing can be saved. In 14D the spatial distribution of the magnetization is substantially symmetrical to the symmetry line 14-0 and shows different degrees of inhomogeneity 14-1 . 14-2 . 14-3 , which refer to the angle α, as it relates to 14A was explained.

It can be seen that the inhomogeneous magnet 400 is beneficial when combined with a magnetic field sensor assembly 120 is used because less magnetic material is required to achieve a comparable inhomogeneous magnetic flux density at the sensor elements 190 to reach. This stems from the fact that the magnet 400 (please refer 14A , C, D) closer to the magnetic field sensor arrangement 120 wherein, for example, a first and a second sensor element 190-1 . 190-2 (please refer 2 . 14C . 14D ) are disposed as may be arranged for the magnet assemblies, which is not a convex shape like the magnet 400 exhibit.

Another advantage of the magnet 400 require the sensor 100 and / or the magnet 400 less space than those systems that include non-convex magnets (such as the magnet) 150 from 1A , the magnet 110 from 3A . 3B . 6A or 6B ). In confined spaces such as an engine compartment of an automotive internal combustion engine, the smaller size of the back-bias sensor system is of interest.

It should be noted that a moving target wheel, which is in the direction 220 rotates, for illustration purposes only 14C and 14D is shown and no part of the described (back-bias) sensor 100 forms.

It will be recognized by experts in the field that the inhomogeneous magnet 400 may be formed by using a hard ferrite material or rare earth as a magnetizable molding material such as ferrites, aluminum-nickel-cobalt (AlNiCo) or samarium-cobalt (SmCo) or neodymium-iron-boron (NdFeB), by some non-limiting examples call.

In general, hard ferrite magnets are cheaper than rare earth based magnets and would in themselves reduce magnetic costs. However, hard ferrite magnets have a weaker magnetic moment and will therefore produce weaker homogeneous magnetic fields compared to rare earth based magnets for homogeneous magnets of the same size. To compensate for this disadvantage, the use of inhomogeneous hard ferrite magnets according to the present disclosure contributes to increasing their respective magnetic field to correspond to the magnetic field strength of the rare earth based magnets at a cost advantage for hard ferrite magnets. In the past, rare earth based magnets have been suitably used for the non-convex magnets described above (see, for example, Magnet 150 from 1A , Magnet 110 from 3A . 3B . 6A or 6B ). That's why the inhomogeneous magnet brings 400 using hard ferrite materials, with a further advantage over non-convex magnets made of rare earth based magnetic materials such as samarium cobalt (SmCo) or neodymium iron boron (NdFeB).

15 schematically illustrates the B _x component with respect to the symmetry line of a magnet (x = 0) for a given y-coordinate. In this regard, the representation of 15 about the scenario in 5 as explained above. It becomes clear that while the B _x component is for a homogeneous magnet (see solid line 15-3 ) has an odd symmetry with respect to x = 0, the B _x component for an inhomogeneous magnet (eg the magnet 400 as discussed above) almost disappears over a substantial range of x coordinates, as seen from the long dashed line 15-4 is apparent. The short-dashed lines 15-1 and 15-2 show typical positions for magnetoresistive sensors, for example GMR detection elements.

As before regarding the course 270-6 discussed (see 5 ), shows the B _x component of the inhomogeneous magnet 400 an increased linear range and would therefore represent a preferred position for GMR sensor elements. The magnetic field sensor elements 190 (ie 2 ), as can be done by position lines 15-1 . 15-2 is indicated, in each case over a wider x-range than for the homogeneous magnet (see line 15-3 from 15 ) can be positioned symmetrically around x = 0. In 15 is for the simulated magnetic field components for the homogeneous and the inhomogeneous magnet (see lines 15-3 and 15-4 ) a distance from the sensor plane with the sensor elements 0.7 mm above the magnet in the z-direction. As indicated, the sensor elements show a sensor pitch or a distance of 2.5 mm in the x-direction.

16 shows a 3D representation of an exemplary simulation of the magnetization for the inhomogeneous magnet 400 from 14 using a standard polymer hard ferrite molding material. These molding materials typically exhibit a remanence magnetic field of about 270 to 280 mT and a corresponding coercive force of 180 kA / m. As can be clearly seen, a spatial distribution of the magnetization within the magnet 400 inhomogeneous, as it is already schematic with respect to 14A was discussed. The color coding as shown on the right side of the scale 16 stated is, shows a strength and direction of magnetization. It will be recognized that the magnetization of the inhomogeneous (back-bias) magnet 400 a magnetic flux density outside the magnet 400 unlike so-called Halbach magnet arrangements, which represent magnet configurations in which nearly the entire magnetic flux density is confined within the Halbach magnet. Such a limitation of magnetic flux to the interior of the magnet would be achievable with non-Halbach magnets if the magnet were infinitely long, high, and / or wide. Out 16 It will also be readily apparent to those skilled in the art that as discussed above, virtually any desired inhomogeneous distribution of magnetization within the magnet 400 can be generated.

17 illustrates further details resulting from the simulation of 16 are taken. Shown is the simulated B _x component of the magnetic field in mT passing through the magnet 400 generated at the symmetry line (see 14-0 from 14 ) for realistic distances of the sensor elements from the surface of the magnet 400 in each case in the y and z directions. The assumed distances are 0.7 mm in the z-direction and a central arrangement in the y-direction (y = 0 mm).

line 17-1 shows the B _x component for a substantially homogeneous magnet, while the lines 17-2 . 17-3 and 17-4 the B _x component for an increasingly inhomogeneous magnet 400 demonstrate. The increasing inhomogeneity for the lines 17-2 . 17-3 and 17-4 can be shown by increasing an angle α (see 14 ) in connection with the line 14-0 to 14-1 . 14-2 and 14-3 being represented. As already for 15 discussed increases the increasingly inhomogeneous magnetization, as in 17 for the lines 17-2 . 17-3 and 17-4 shown a linear region of the magnetoresistive sensor elements 190 (not shown) to be placed in the x direction, as indicated by the dotted lines 15-1 . 15-2 is specified.

As the B _x component for the strongest inhomogeneity by the line 17-4 is shown at the sensor positions 15-1 respectively. 15-2 almost disappears, this degree of inhomogeneity of the B _x component would affect the sensor positions 15-1 and 15-2 to make ideal positions for arranging the sensor elements in the x-direction, as previously with reference to 5 has been described.

It has been described by those skilled in the art that the present disclosure includes inhomogeneous magnetization of the magnet 400 (please refer 1A . 1B . 3A . 3B . 4 - 14 . 14A . 14D . 15 - 17 ) in cross sections of the inhomogeneous magnet, such as the xy or xz plane, for illustrative purposes only. However, the inhomogeneous magnet of the present disclosure is in no way limited to such a scenario. The magnet may therefore comprise further inhomogeneous magnetization contributions within further cross sections of the magnet, the further cross sections being perpendicular to those illustrated in the figures of the present disclosure.

Depending on the circumstances, embodiments of the inventive method can be implemented in hardware or in software. The implementation can be carried out on a digital storage medium, in particular a floppy disk, CD or DVD with electronically readable control signals, which can cooperate with a programmable computer system so that an embodiment of a method according to the invention is carried out. In general, an exemplary embodiment of an invention thus also exists in a software program product or a computer program product with a program code stored on a machine-readable carrier for carrying out an exemplary embodiment of a method according to the invention when the software program product runs on a computer or a processor. In other words, an embodiment of the present application can thus be realized as a computer program or a software program or program with a program code for carrying out an embodiment of a method, when the program runs on a processor. The processor may each be constituted by a computer, a smart card, a central processing unit (CPU), an application specific integrated circuit (ASIC) or other integrated circuit.

Computer programs, software programs or programs can be used here, for example, in the context of the production method, that is to say, for example, for controlling the production of corresponding exemplary embodiments of magnetic field sensors. Corresponding programs can therefore be used and used in the context of manufacturing systems for controlling these, but also in the context of the design and in the context of the design of corresponding embodiments of magnetic field sensors. Processors are thus, as already shown in the previous list, understood not only in the sense of classical computer processors, but also in the sense of application-specific processors, as they occur, for example, in the context of machine tools and other production-related equipment.

Although this invention has been described in terms of several embodiments, there are variations, permutations, and equivalents that fall within the scope of this invention. It should also be noted that there are many alternative ways to implement the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007025000 [0001]

Claims (20)

Magnetic field sensor comprising: a magnetic field sensor arrangement; and a back-bias magnet, wherein the back-bias magnet comprises an inhomogeneous magnetization. A magnetic field sensor according to claim 1, wherein said back bias magnet is shapeable as a unitary element and of cube shape, circular shape, elliptical or frusto-conical shape. A magnetic field sensor according to claim 1 or 2, wherein the back-bias magnet comprises materials selected from the group consisting of ferrites, aluminum-nickel-cobalt (AlNiCo), samarium-cobalt (SmCo), and neodymium-iron-boron ( NdFeB). Magnetic field sensor according to one of the preceding claims, wherein the inhomogeneous magnetization of the back-bias magnet is symmetrical to a first line of symmetry within at least one cross-section of the back-bias magnet. The magnetic field sensor of claim 4, wherein the first line of symmetry is a line of symmetry of substantially mirror-symmetric inhomogeneous magnetization within the at least one cross-section of the back-bias magnet. The magnetic field sensor of claim 4, wherein the first line of symmetry within the at least one cross-section of the back-bias magnet is a line of symmetry of higher order, rotational symmetry, or ellipsoidal symmetry. The magnetic field sensor of claim 4, wherein the inhomogeneous magnetization is further symmetrical about the line of symmetry within a further cross section of the back bias magnet, the further cross section intersecting the cross section at the line of symmetry. Magnetic field sensor according to one of the preceding claims, wherein the inhomogeneous magnetization of the back-bias magnet causes a magnetic flux density outside of the back-bias magnet. Magnetic field sensor according to one of the preceding claims, wherein the magnetic flux caused by the magnetization is substantially not enclosed in the interior of the back-bias magnet. Magnetic field sensor according to one of the preceding claims, wherein the back-bias magnet comprises the inhomogeneous magnetization in at least 50% of a volume of the back-bias magnet. A magnetic field sensor according to any one of claims 4 to 10, wherein the at least one cross section is spanned by a first direction and a second direction, wherein the first and second directions are not parallel, and wherein, for a given coordinate value of the first direction along the second direction, an angle between the second direction and a local direction of the magnetization varies over at least a portion of the path, wherein the path deviates from the first line of symmetry. A magnetic field sensor according to claim 11, wherein the local direction of magnetization varies monotonously as one travels along the path. A magnetic field sensor according to claim 11, wherein the angle varies non-monotonically when traveling along the path if the path is perpendicular to the line of symmetry. Magnetic field sensor according to one of claims 1 to 13, wherein the magnetic field sensor arrangement comprises a first magnetic field sensor element and a second magnetic field sensor element, wherein the first magnetic field sensor element is arranged, with respect to the back-bias magnet, that the first magnetic field sensor element, with respect to a predetermined spatial direction , a magnetic flux density caused by the back-bias magnet and exposed within a first range of flux density, and wherein the second magnetic field sensor element arranged, with respect to the back-bias magnet, that the second magnetic field sensor element, with respect to the predetermined spatial direction, is exposed to a magnetic flux density caused by the back-bias magnet and within a second range of flux density. The magnetic field sensor of claim 14, wherein the first flux density region and the second flux density region permit operation of the first and second magnetic field sensor elements outside a saturation region. A magnetic field sensor according to claim 14 or 15, wherein the first and second flux density ranges only include values less than or equal to 20 mT. A magnetic field sensor according to any one of claims 14 to 16, wherein the first flux density region comprises flux densities of the opposite polarity of the second flux density region. A magnetic field sensor according to any one of claims 14 to 17, wherein the first and second magnetic field sensor elements are magneto-resistive sensor elements. A magnetic field sensor according to any one of claims 14 to 18, wherein the first and second magnetic field sensor elements are disposed on a substrate, and wherein the predetermined spatial direction is substantially parallel to a major surface of the substrate. Magnetic field sensor according to one of the preceding claims, wherein the back-bias magnet is annular or comprises an annular portion.

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