Sensor elements for storing rotational or positional information

Abstract

To provide a sensor element for storing rotation or position information, comprising a domain wall conductor arranged on a substrate.SOLUTION: A course of a domain wall conductor is of a closed circumferential, continuous configuration without crossings. The domain wall conductor has a first region having a positive curvature and a second region having a negative curvature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a sensor element for storing rotational or positional information, e.g. for an angle or length measuring device as claimed in claim 1 . [Background technology]

[0002] Angle measuring devices are used, for example as rotary encoders, to measure the angular position of two machine parts which can rotate relative to one another. For this purpose, so-called multi-turn angle measuring devices are often used, which allow absolute position measurements over multiple revolutions.

[0003] Furthermore, length measuring devices are known in which the linear movement of two machine parts that can be moved relative to one another is measured. In particular, in the case of length measuring devices with a relatively large measuring length, a number of linear scales or identical graduations are usually arranged in a daisy chain. In the case of such length measuring devices, absolute position measurement must be possible as far as possible over the entire measuring length.

[0004] Often such measuring devices or measuring instruments for electric drives are used to measure the relative movement or relative position of corresponding machine parts, the position values ​​generated then being supplied by corresponding interface devices to subsequent electronic devices for controlling the drive.

[0005] EP 1 740 909 B1 describes a sensor element for generating magnetic domain walls for revolution counters, the sensor element being in the form of a spiral. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 1740909 Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the invention to provide a sensor element or storage system which has domain wall conductors, allows a robust operating behavior with respect to external influences and can be produced relatively economically. [Means for solving the problem]

[0008] According to the invention, this problem is solved by the features of claim 1.

[0009] The sensor element, particularly for actively storing rotational or positional information, comprises a domain wall conductor and a substrate, the path of which is formed in a closed loop, without crossings and continuously on the substrate, and furthermore the domain wall conductor has at least one first region with a convex curve and at least one second region with a concave curve.

[0010] The term actively storing refers to storage in which the corresponding sensor element does not require auxiliary power for storage.

[0011] In the context of the present invention, a domain wall conductor is in particular a conductor track or a conductive path or a nanowire made of a magnetizable material. Information can be stored in the domain wall conductor as opposing magnetic domains (regions). These domains are separated by said domain walls, which can be displaced by a magnetic field. In this case, the position of the magnetic domains changes. A number of reading elements are arranged to measure said position. The magnetic domains or domain walls pass by these reading elements. From a functional point of view, the domain wall conductor can therefore also be regarded as a kind of shift register.

[0012] The path of the domain-wall conductor forms one continuous curved section and does not have any cracks, tapers, bends or other discontinuities. The term continuous path therefore means a path of the domain-wall conductor that is uniformly formed without any abrupt changes in direction. In other words, mathematically expressed, the path of the domain-wall conductor is continuous over its entire length and, in particular, differentiable. As a result, a unique tangent can be generated at each point of the path of the domain-wall conductor.

[0013] Non-crossing paths of the domain wall conductors means in particular that the paths of the domain wall conductors do not cross and are not laid one on top of the other so as to cross at different positions.

[0014] Curvature means a portion whose direction does not change along the path of the domain wall conductor on a particularly flat substrate. In the case of a straight path, the curvature is non-existent, since the direction of the path does not change. For the path of the domain wall conductor, the curvature, if any, is defined by the change in the direction of the normal of the curve of the path. If the curvature is curved in the direction of the unit normal vector field, the curvature is convex, if the curvature is curved in the opposite direction, the curvature is concave. For example, a first region with a convex curvature can be called a convex region, whereas a second region with a concave curvature can be called a concave region. Expressed mathematically, the path of the domain wall conductor therefore has in particular at least one inflection point.

[0015] Preferably, the sensor element has a particularly flat substrate, the domain wall conductors being formed as conductive tracks on the substrate.

[0016] In a further configuration of the invention, the width of the domain wall conductor is less than 1000 nm, in particular less than 500 nm, preferably less than 300 nm.

[0017] The thickness or layer thickness of the domain wall conductor is preferably less than 200 nm, in particular less than 150 nm, in particular less than 60 nm.

[0018] Preferably, the substrate comprises a glass layer and / or a silicon layer, in particular if the substrate comprises a silicon layer the sensor element may be constructed as part of a CMOS chip.

[0019] According to a preferred variant, the sensor element further comprises a read element, by means of which the local magnetization state of the domain wall conductor (at the respective position of the read element) is determinable, and thus the magnetization state of the domain wall conductor is determinable by means of the read element, which is fixedly arranged on the domain wall conductor.

[0020] In another configuration of the invention, the domain wall conductor is disposed in a layer between at least one of the read elements and the substrate, or alternatively or additionally, at least one of the read elements is disposed in a layer between the substrate and the domain wall conductor.

[0021] Preferably, the read element is configured as a GMR or TMR sensor.

[0022] The sensor element may have several domain wall conductors, where these domain wall conductors have a different number of first regions or a different number of second regions. Thus, for example, the sensor element may have one first domain wall conductor and one second domain wall conductor, where the first domain wall conductor has a first number of first regions and the second domain wall conductor has a second number of first regions.

[0023] Preferably, the different numbers, i.e., the number of the first regions of the first domain wall conductor and the number of the first regions of the second domain wall conductor, are mutually prime. As is well known, being mutually prime means that there is no natural number other than 1 that divides both of the two numbers.

[0024] According to another aspect, the invention includes a storage system having a sensor element, a read element and a magnet arrangement, the magnet arrangement being movable in a first direction relative to a domain wall conductor, thereby causing a plurality of magnetic domains or a plurality of domain walls to move.

[0025] Preferably, the magnetic field generated by the magnet arrangement is formed asymmetrically with respect to an axis extending parallel to the first direction, the considerations also being valid for any conceivable axis extending parallel to the first direction.

[0026] In a further embodiment of the invention, the magnetic field generated by the magnet arrangement is preferably symmetrical with respect to an axis extending parallel to a second direction, the second direction being oriented perpendicular to the first direction.

[0027] The axis extending parallel to the first direction and the axis extending parallel to the second direction lie in a plane that is oriented in particular parallel to the substrate.

[0028] In another configuration of the storage system, the magnet arrangement is configured as a magnet array having a plurality of magnets whose magnetic poles are offset from one another in the first direction.

[0029] Preferably, two magnets offset from one another in the first direction x have magnetic pole directions rotated by 180°. The magnets are therefore arranged such that the magnetic field lines between the north and south poles of one magnet are parallel to the magnetic field lines between the north and south poles of the other magnet. In this case, the magnetic pole directions of the magnets are opposed to one another. The magnetic pole directions of the offset magnets are therefore shown oriented anti-parallel to one another.

[0030] In another configuration of the storage system, the magnet array includes a plurality of magnets whose poles are offset from one another in a second direction, where the second direction is oriented perpendicular to the first direction.

[0031] Preferably, the magnets are offset from one another in the second direction, in particular two adjacent magnets having magnetic pole directions rotated by 180°.

[0032] Preferably, the paths of the domain wall conductors are formed asymmetrically, in particular the corresponding axis of symmetry can run parallel to or in the second direction.

[0033] The domain wall conductor has an extension in a first direction and the two poles have a center-to-center distance, where the extension is smaller than the center-to-center distance, where in particular the maximum extension of the domain wall conductor is seen in the first direction. The center-to-center distance may in particular be the distance between the effective centers of the magnets. For example in the case of a cylindrical bar magnet, the center-to-center distance may be considered as the distance between the longitudinal axis of the cylindrical bar magnet and the longitudinal axis of the cylindrical bar magnet.

[0034] The storage system is configured so that it has at least two domain walls, although configurations with four or more domain walls may also be used.

[0035] Preferred configurations of the invention are set forth in the dependent claims.

[0036] Further details and advantages of the sensor of the invention are described in the following exemplary embodiments on the basis of the attached drawings. [Brief description of the drawings]

[0037] [Figure 1] FIG. 2 is a front view of the sensor element. [Diagram 2] FIG. [Diagram 3] 1 shows a plurality of magnets of a magnet arrangement; [Figure 4] FIG. 4 is a front view of the magnet device on the mounting plate. [Diagram 5] FIG. 2 is a front view of the magnet arrangement with the magnetic field shown diagrammatically. [Figure 6] FIG. 2 is a side view of the scale element according to the first embodiment. [Figure 7] FIG. 2 is a front view of the scale element and the sensor element according to the first embodiment. [Figure 8] 4 is a schematic diagram of a sensor element and a magnet device facing each other in a first relative position. FIG. [Figure 9] FIG. 2 is a partial view of a domain wall conductor with the domain walls marked in a first relative position. [Figure 10] FIG. 13 is a schematic diagram of a sensor element and a magnet device facing each other in a second relative position. [Figure 11] FIG. 13 is a partial view of a domain wall conductor with the domain walls marked in a second relative position. [Figure 12] FIG. 13 is a schematic diagram of a sensor element and a magnet device facing each other in a third relative position. [Figure 13] FIG. 13 is a partial view of a domain wall conductor with the domain walls marked in a third relative position. [Figure 14] FIG. 13 is a schematic diagram of a sensor element and a magnet device facing each other in a fourth relative position. [Figure 15] FIG. 11 is a partial view of a domain wall conductor with the domain walls marked in a fourth relative position. [Figure 16] FIG. 13 is a schematic diagram of a sensor element and a magnet device facing each other in a fifth relative position. [Figure 17] FIG. 13 is a partial view of a domain wall conductor with domain walls marked in a fifth relative position. [Figure 18] FIG. 13 is a schematic diagram of a sensor element and a magnet device facing each other in a sixth relative position. [Figure 19] FIG. 13 is a partial view of a domain wall conductor with domain walls marked in a sixth relative position. [Figure 20] FIG. 13 is a front view of the domain wall conductor with the domain walls marked in different relative positions during a second rotation. [Figure 21] FIG. 13 is a front view of the domain wall conductor with the domain walls marked in different relative positions after completing a second rotation. [Figure 22] FIG. 13 is a front view of the domain wall conductor with the domain walls marked in different relative positions after completing a third revolution. [Diagram 23] FIG. 13 is a front view of the domain wall conductor with the domain walls marked in different relative positions after completing a fourth revolution. [Figure 24] FIG. 13 is a front view of a sensor element having another domain wall conductor. [Diagram 25] FIG. 11 is a front view of a scale element according to a second embodiment. [Figure 26] FIG. 13 is a front view of a scale element according to a third embodiment. [Figure 27] FIG. 13 is a front view of a sensor element according to a fourth embodiment. [Figure 28] FIG. 13 is a front view of a magnet device according to a fourth embodiment. [Figure 29] FIG. 13 is a side view of a magnet arrangement having a sensor element according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] FIG. 1 shows a sensor element with a domain wall conductor 1 and a substrate 2. In this case, the domain wall conductor 1 is formed as a conductive path on the substrate 2. In the illustrated embodiment, the substrate 2 has a mechanically supporting glass layer. In this case, the substrate 2 is formed. Alternatively, the substrate 2 may have a silicon layer. In this case, the sensor element can be formed as part of a COS chip.

[0039] The domain wall conductor 1 comprises a soft magnetic material, for example a Ni-Fe alloy. The domain wall conductor 1 comprises a first part 1.1, in which the domain wall conductor 1 extends in a number of bends with a relatively small radius, and a second part 1.2, in which the domain wall conductor 1 extends in a bend with a relatively large radius. The first part 1.1 and the second part 1.2 are directly adjacent to each other, so that the path of the domain wall conductor 1 is formed in the form of a closed loop. The domain wall conductor 1 has a width X1 in the first direction x and is formed symmetrically with respect to an axis C oriented perpendicular to the first direction x and parallel to the second direction y. In the illustrated embodiment, the width X1 is 70 μm. In this case, the domain wall conductor 1 extends over 5 mm in the second direction y.

[0040] In FIG. 2, a part of the domain-wall conductor 1 is shown. It can be seen in this figure that the domain-wall conductor 1 has a first region A with a convex curve and a second region B with a concave curve in its path. In other words, the path of the domain-wall conductor 1 includes a concave curve and a convex curve. For each path of the first portion 1.1, the concave curved second region B follows the convex curved first region A, which again follows the second region B. In this case, in the illustrated embodiment, a region with a straight path of the domain-wall conductor 1 is present between the first region A and the second region B. In the second portion 1.2, the direction of the curve does not change. In the illustrated embodiment, the curve or radius of curvature of said second portion 1.2 is formed constant.

[0041] 1, a read element 7, which may be for example a GMR or TMR sensor, is present in a layer above the domain wall conductor 1. The magnetization state of the domain wall conductor 1 below the read element 7 can be detected by the read element 7. Alternatively, the read element 7 may be arranged between the domain wall conductor 1 and the substrate 2.

[0042] When a magnetic field moving relative to the magnetic domain wall conductor 1 acts appropriately on this magnetic domain wall conductor 1, the magnetic domain walls W1, W2 move in or along the magnetic domain wall conductor 1. In the illustrated embodiment, a magnet arrangement 3 configured as a magnet array of a number of magnets 3.1-3.6 is used to generate the appropriate magnetic field. The magnet 3.1 is shown in FIG. 3 as representative of all the magnets 3.1-3.6. In the illustrated embodiment, all the magnets 3.1-3.6 are formed identically. These magnets 3.1-3.6 are therefore formed as cylindrical bodies. In this case, for bar magnets, the magnetic poles are arranged along a longitudinal axis of symmetry.

[0043] A corresponding magnet arrangement 3 is shown in Fig. 4. This magnet arrangement 3 is shown on a different scale than the domain wall conductor 1 in Fig. 1. The magnets 3.1-3.6 are arranged according to a predefined pattern on the carrier 4 with different south-north pole orientations. The magnets 3.1-3.6 may be embedded in the carrier 4.

[0044] In particular, the magnets 3.1 to 3.3 may be arranged in series with a spacing X2 along the first direction x. In this case, adjacent magnets 3.1 and 3.2 or 3.2 and 3.3 have opposite magnetic pole directions. Further magnets 3.4 to 3.6 are arranged in series with a spacing X2 along the first direction x, offset in the second direction y. In the illustrated embodiment, the spacing X2 is 0.33 mm. The magnet 3.6 is offset in the second direction y with respect to the other magnets 3.1 to 3.5.

[0045] An assist magnetic field is provided on both sides of the magnet arrangement 3 in the direction x. This can therefore be shown in a simplified manner according to FIG. 5. In this case, the thick arrows on the left and right of the magnets 3.1 to 3.6 indicate the assist magnetic field. In FIG. 5 it can be seen that the direction of the magnetic field lines changes so that rotating or swirling magnetic field lines are generated. In this case there is a rotation of the magnetic field lines around a number of axes oriented in a third direction z (see FIG. 3).

[0046] The magnetic field generated by the magnet arrangement 3 is asymmetrically configured with respect to an axis Ax extending parallel to the first direction x. In particular, there is no axis extending parallel to the first direction x that could represent an axis of symmetry. In contrast, the magnetic field generated by the magnet arrangement 3 is symmetrically configured with respect to an axis Ay extending parallel to the second direction y. As a result, an axially symmetric magnetic field exists with respect to the axis Ay.

[0047] Alternatively to the configuration shown here, the bar magnets may lie in a plane oriented parallel to the first direction x and parallel to the second direction y, so that at least some of the north poles and south poles shown in Fig. 5 belong to one and the same magnet, in particular magnets lying in the xy plane.

[0048] In general, the magnet arrangement 3 is fixed to the scale element 6 or to the scale body. According to a first embodiment according to Figs. 6 and 7, the scale element 6 has as its body an approximately ring-shaped drum 6.1. The magnet arrangement 3, consisting of the magnets 3.1-3.6 and the carrier 4, is attached to the outer circumference of this drum 6. Furthermore, the drum 6.1 has an auxiliary magnet 6.11 in the region of said outer circumference. This auxiliary magnet 6.11 can for example consist of a layer of magnetizable material. The magnetization is carried out in such a way that the north and south poles are arranged axially offset from one another. In the illustrated embodiment, a fine graduation 6.12 is provided around the drum 6.1 in the second direction y, i.e. in the axial direction, offset with respect to the auxiliary magnet. This drum 6.1 can be decoded, for example, by an optical scanning device, which is also accommodated in the housing 5. Alternatively, the magnet arrangement 3 can also be arranged on the inner circumference or on the hollow shaft of the drum.

[0049] Opposite to each other across a magnetic gap, the sensor element, i.e. the domain wall conductor 1 with the substrate 2, is present in a housing 5. In the illustrated embodiment, the housing 5 is fixed, while the drum 6.1 is journalled so as to be rotatable together with the magnet arrangement 3, so that the magnet arrangement 3 moves in the x-direction (or in the opposite direction) relative to the magnet arrangement 3 upon rotation of the drum 6.1.

[0050] In Fig. 8, the magnet arrangement 3 and the domain wall conductor 1 facing each other in a first position are shown diagrammatically. In this position, the domain walls W1, W2 are in the position according to Fig. 9. In this case, the first domain wall W1 is a so-called head-to-head domain wall and the second domain wall W2 is a so-called tail-to-tail domain wall (as indicated by the symbols). When the domain wall conductor 1 together with the substrate 2 moves in the first direction x relative to the magnet arrangement 3 according to the arrow in Fig. 8, it is as if the domain wall conductor 1 passes through a rotating magnetic field, as shown in Fig. 5. As a result, the positions of the domain walls W1, W2 are shifted.

[0051] In figure 10 the domain wall conductor 1 is shown in another position. In this case the magnetic field has been rotated with respect to the first position. Hence the domain walls W1, W2 have changed their position (figure 11).

[0052] Similarly, due to further movement of the domain wall conductor 1 along the first direction x (FIGS. 12, 4, 16, 18), the positions of the domain walls W1, W2 are further shifted (FIGS. 13, 15, 17, 19). The position of the domain walls W1, W2 according to FIG. 19 contains, for example, the information that the drum 6.1 has completed a first revolution.

[0053] When the magnetic field is further moved or rotated in the same direction, the magnetic domain wall conductor 1 continues to be influenced by the assistant magnetic field, so that the positions of the magnetic domain walls W1 and W2 do not change any more.

[0054] In the illustrated embodiment, the drum 6.1 is rotated further in the same direction x, so that the domain wall conductor 1 is again in the magnetically influenced region of the magnet arrangement 3 at the end of the second rotation. In FIG. 20 the positions of the domain walls W1, W2 during the second rotation are shown. In this case the domain wall conductor 1 with the substrate 2 is in the position according to FIG. 14 (however, now the drum 6.1 has been rotated further by 360°). In particular, due to the magnet 3.6 or the magnetic field of the assist region, which is offset in the second direction y, the domain walls W1, W2 move over the length of the second part 1.2, which extends in a curved section of a relatively large radius. If, at the end of the second rotation, the domain wall conductor 1 is in the position according to FIG. 18 (with the drum 6.1 being rotated further by 360° relative to the situation in FIG. 18), the domain walls W1, W2 take up the position according to FIG. 21.

[0055] Figure 22 shows the position of the domain walls W1, W2 after the third rotation of the drum 6.1, in which the domain wall conductor 1 is in the position according to Figure 18 (however, the drum 6.1 has now been rotated further by 720°).

[0056] 23 shows that the drum 6.1 has completed a fourth rotation (although the position of the drum 6.1 has been rotated further by 1080°) The positions of these domain walls W1, W2 correspond to the positions of these domain walls W1, W2 in the initial state.

[0057] Thus, with each passing by the magnet arrangement 3 or with each rotation of the drum 6.1, the domain wall W1 moves in each case further towards the adjacent first region A of the domain wall conductor 1. Correspondingly, the domain wall W2 moves in each case further towards the adjacent second region B of the domain wall conductor 1 with each rotation or the domain wall W2 is in a second part 1.2 in which the domain wall conductor 1 extends in a curved section of a relatively large radius.

[0058] The magnetization direction in the part of the domain wall conductor 1 and the coarse position of the domain walls W1, W2 can be detected by the read element 7. In this way, the counting of revolutions or the storage of the rotation information is possible even when no auxiliary power is available. The counting of revolutions or the storage of the rotation information is important when the shaft is affected in the event of a power failure, for example by a load load. Furthermore, the domain walls W1, W2 move depending on the direction of rotation. As a result, the sensor element can be used reliably in applications that allow both directions of rotation.

[0059] In order to increase the number of countable rotations, a plurality of domain wall conductors 1 may be provided, as shown in a simplified manner in FIG. 24. In this case, it is advantageous for the plurality of domain wall conductors 1 to have a different number of first portions 1.1, in particular a different number of first regions A, or a different number of second regions B. When using a plurality of domain wall conductors 1, it is advantageous for the number of regions A to be particularly prime to each other. The plurality of domain wall conductors 1 may be arranged offset from each other in the first direction x, or may be nested within each other. In FIG. 24, these domain wall conductors are configured such that they have four and five first regions A. In this case, for the sake of clarity, a plurality of domain wall conductors with a relatively small number of first regions are shown in FIG. 24. In practice, domain wall conductors with more than four first regions can be used. For example, four domain wall conductors with 7, 9, 11, 13 first regions can be used. As a result, then 9009 (7×9×11×13) rotations can be counted.

[0060] It is important for the functioning of the storage system that when passing by the magnet arrangement 3 along a first direction x, a magnetic field acts on the domain wall conductor 1, the direction of which changes depending on the position of x. In particular, here, there are magnetic field lines or magnetic field lines that rotate or swivel when passing by. When passing by (without a change of direction), the magnetic field lines (FIG. 5) on one side of the axis Ax have an opposite direction of rotation relative to the magnetic field lines on the other side of the axis Ax.

[0061] A second embodiment is shown in Fig. 25. Here, the magnet arrangement 3 is fixed to the front side of the drum 6.1. The sensor elements shown in this figure are arranged axially offset, i.e. with an axially extending magnetic gap. Each time the magnet arrangement 3 passes by the sensor elements, the rotation information is updated. In this case, the magnetic domain walls W1, W2 move depending on the direction of rotation.

[0062] A third embodiment is described according to FIG. 26. In this embodiment, a sensor element is used according to a linear scale 6.3. In the illustrated embodiment, this scale 6.3 has a first scale graduation 6.31 and a second scale graduation 6.32. The first scale graduation 6.31 and the second scale graduation 6.32 are arranged in a daisy chain along the first direction x. As a result, relatively large measuring dimensions can be achieved. In practice, more than two scale graduations may be arranged in a daisy chain. The first scale graduation 6.31 has an auxiliary magnet 6.311 and the second scale graduation 6.32 has an auxiliary magnet 6.321. A plurality of magnet arrangements 3 are provided laterally offset in the first direction x with respect to the auxiliary magnets 6.311, 6.321. A scanning head, not shown in Fig. 26, comprises a sensor element with a domain wall conductor 1 and a scanning device for the incremental tracks 6.313, 6.323 and the absolute tracks 6,312, 6.322 (the incremental tracks 6.313, 6.323 and the absolute tracks 6,312, 6.322 extend over the two scale divisions 6.31, 6.32). By means of the sensor element, position information can be stored, so that it can be ascertained which of the scale divisions 6.31, 6.32 is currently being scanned.

[0063] A fourth embodiment is described with reference to Figs. 27-29. Fig. 27 shows a sensor element with a domain wall conductor 1' which is different from the previous embodiment. This domain wall conductor 1' extends around a central rotation point (the reading element is omitted in this figure). For example, a magnet arrangement 3' is used to move the domain walls. According to Fig. 28, this magnet arrangement 3' has two magnets 3.1', 3.2', which are in particular disk-shaped and have different diameters. The magnets 3.1', 3.2' are magnetized in the diametric direction. As a result, the magnetic poles are arranged radially offset from one another. The magnets 3.1', 3.2' are arranged offset from one another along the axis G (i.e. in the multi-rail direction). In this case, the direction of the magnetic poles of these magnets is rotated by 180° with respect to the axis G. The magnets 3.1', 3.2' themselves are fixedly integrated into the corresponding storage system and therefore cannot rotate relative to one another and in any case cannot move relative to one another. As shown in FIG. 29, the gap g1 between the magnetic domain wall conductor 1′ or the substrate 2 and the magnet 3.1′ having a larger diameter is larger than the gap g2 between the magnetic domain wall conductor 1′ or the substrate 2 and the magnet 3.2′ having a smaller diameter (g1>g2). In this way, a magnetic field can be generated. When the magnetic domain wall conductor 1′ or the substrate 2 rotates relative to the magnet device 3′ around the axis G or moves relative to the magnet device 3′ along the first direction x, the magnetic domain walls are appropriately moved by the magnetic field. This makes it possible to count the number of rotations of the substrate 2 relative to the magnet device 3′. The present application relates to the invention described in the claims, but may also include the following configurations as other aspects. 1. A sensor element for storing rotational or positional information, comprising a domain wall conductor (1;1') arranged on a substrate (2), The path of the domain wall conductor (1;1') is formed in a closed loop shape, continuously and without intersections, and the domain wall conductor (1;1') has a first region (A) forming a convex curved portion and a second region (B) forming a concave curved portion. 2. The sensor element according to claim 1, wherein the domain wall conductor (1;1') is formed on the substrate (2) as a conductive path. 3. 3. The sensor element according to any one of 1 to 2 above, wherein the width (D) of the domain wall conductor (1;1') is less than 1000 nm. 4. 4. The sensor element according to any one of 1 to 3 above, wherein the substrate (2) has a glass layer and / or a silicon layer. 5. The sensor element according to any one of 1 to 4 above, further comprising a read element (7), the local magnetization state of the domain wall conductor (1;1') being identifiable by the read element (7). 6. 6. A sensor element according to claim 5, wherein the domain wall conductor (1;1') is arranged in a layer between at least one read element (7) and the substrate (2). 7. 7. A sensor element according to claim 5 or 6, wherein at least one read element (7) is arranged in a layer between the substrate (2) and the domain wall conductor (1). 8. The sensor element according to any one of claims 5 to 7, wherein the reading element (7) is configured as a GMR sensor or a TMR sensor. 9. The sensor element according to any one of 1 to 8, comprising a plurality of domain wall conductors (1;1') having a different number of first regions (A) and a different number of second regions (B). 10. 10. The sensor element according to claim 9, wherein the different numbers of the plurality of first regions (A) are mutually prime. 11. A storage system having the sensor element according to any one of claims 5 to 10 and a magnet device (3; 3'), The storage system, wherein the magnet device is movable relative to the domain wall conductor (1;1') in a first direction (x;x'). 12. The storage system described in claim 11, wherein the magnet device (3) is configured as a magnet array having a plurality of magnets (3.1 to 3.6), and the magnetic poles of these magnets are arranged offset from each other in the first direction (x). 13. The magnet array has a plurality of magnets (3.1 to 3.6), the magnetic poles of which are arranged offset from one another in a second direction (y), 13. The storage system according to claim 11 or 12, wherein the second direction (y) is oriented perpendicular to the first direction (x). 14. The domain wall conductor (1) has an extension portion (X1) in the first direction (x), and the two magnetic poles of the magnet device (3) have a center distance (X2), 14. The storage system according to any one of the above 11 to 13, wherein the extending portion (X1) is smaller than the center-to-center distance (X2). 15. The storage system according to any one of the above 11 to 14, wherein in addition to the magnet device (3), an assist magnet (6.11) is arranged along the first direction (x). [Explanation of symbols]

[0064] 1. Domain Wall Conductor 1' Domain wall conductor 2. Board 1.1 Part 1 1.2 Second part 3. Magnet device 3′ Magnet device 3.1~3.6 Magnets 3.1′,3.2′ Magnets 4. Career 5. Housing 6 Scale Elements 6.1 Drums 6.11 Assist magnet 6.12 Scale 6.3 Linear Scale 6.31 First scale division 6.32 Secondary scale divisions 6.311,6.321 Assist magnet 6.313,6.323 Incremental Track 6.312,6.322 Absolute Track 7 Reading elements A 1st area B 2nd area C axis D width X1 width, extension X2 spacing, center spacing g1 Interval g2 interval W1 1st domain wall W2 2nd domain wall Ax,Ay Axis line G axis x 1st direction y second direction z 3rd direction

Claims

1. A sensor element for storing rotational or positional information, comprising a domain wall conductor (1; 1') arranged on a substrate (2), The path of the domain wall conductor (1;1') as a conductor track or conductive path or nanowire is formed continuously in the form of a closed loop, without crossings and without discontinuities, and the domain wall conductor (1;1') has a first region (A) forming a convex curved portion and a second region (B) forming a concave curved portion, When a magnetic field moving relative to the domain wall conductor (1;1') acts on the domain wall conductor (1;1'), the domain walls (W1, W2) move within the domain wall conductor (1;1').

2. 2. The sensor element according to claim 1, wherein the width (D) of the domain wall conductor (1;1') is less than 1000 nm.

3. 3. The sensor element according to claim 1 or 2, wherein the substrate (2) comprises a glass layer and / or a silicon layer.

4. The sensor element according to any one of claims 1 to 3, further comprising a read element (7), by means of which the local magnetization state of the domain wall conductor (1;1') can be determined.

5. 5. A sensor element according to claim 4, wherein the domain wall conductor (1; 1') is arranged in a layer between at least one read element (7) and the substrate (2).

6. 6. A sensor element according to claim 4 or 5, wherein at least one read element (7) is arranged in a layer between the substrate (2) and the domain wall conductor (1).

7. The sensor element according to any one of claims 4 to 6, wherein the read element (7) is configured as a GMR sensor or a TMR sensor.

8. The sensor element according to any one of the preceding claims, comprising a plurality of domain wall conductors (1; 1') having a different number of first regions (A) and a different number of second regions (B).

9. The sensor element according to claim 8 , wherein the different numbers of the plurality of first regions (A) are mutually prime.

10. A storage system comprising a sensor element and a magnet arrangement (3; 3') according to any one of claims 4 to 9, The storage system, wherein the magnet arrangement is movable relative to the domain wall conductor (1;1') in a first direction (x;x').

11. 11. The storage system according to claim 10, wherein the magnet device (3) is configured as a magnet array having a plurality of magnets (3.1 to 3.6), the magnetic poles of which are offset from one another in the first direction (x).

12. The magnet array comprises a plurality of magnets (3.1 to 3.6) whose magnetic poles are offset from one another in a second direction (y); 12. The storage system of claim 11, wherein the second direction (y) is oriented perpendicular to the first direction (x).

13. The magnetic domain wall conductor (1) has an extension portion (X1) in the first direction (x), and the two magnetic poles of the magnet device (3) have a center distance (X2), 13. The storage system according to claim 10, wherein the extending portion (X1) is smaller than the center distance (X2).

14. A storage system according to any one of claims 10 to 13, wherein in addition to the magnet arrangement (3) an assist magnet (6.11) is arranged along the first direction (x).

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