Scanning element and inductive position measuring device having the scanning element

Abstract

To provide a scanning element and an inductive position measuring device with the scanning element.SOLUTION: A scanning element 1 includes a circuit board and electronic components. The circuit board includes a first shield layer and a second shield layer, a first detector unit is arranged in a first layer A and a second layer B, and a second detector unit is arranged in a third layer E and a fourth layer F. In the shield layer, a first straight line g1 penetrates through both the first detector unit and the first shield layer, while the second shield layer is not penetrated by the first straight line g1. Starting from the first detector unit, the first shield layer is arranged beyond the center plane M.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The invention relates to a scanning element for an inductive position measuring device according to claim 1 for determining the position of the scanning element relative to two scale elements movable at different speeds. Inductive position measuring devices are used, for example, as angle measuring devices for determining the angular position of relatively rotatable machine parts. In inductive position measuring devices, excitation lines and receiving lines are often applied, for example in the form of conductor tracks, to a common, usually multi-layered printed circuit board, which is fixedly connected, for example, to the stator of the angle measuring device. Opposite this printed circuit board are scale elements, which are provided with a pitch structure and are non-rotatably connected to the rotor of the angle measuring device. If a time-varying excitation current is applied to the excitation lines, a signal dependent on the angular position is generated in the receiving coil during the relative rotation of the rotor and the stator. These signals are then further processed in the evaluation electronics.

[0002] In particular, in robot drives, inductive position measuring devices are frequently used as measuring devices for determining the angular position of the drive shaft and at the same time accurately determining the angular position of the driven shaft, the movement of which is introduced into the driven shaft by a reducer, whereby the angular position is measured using a scanning element comprising a printed circuit board with corresponding detector units on both sides, so that the respective angular positions of the scale elements rotatably arranged on both sides of the printed circuit board can be determined.

[0003] Inductive position measuring devices are also used as length measuring devices for determining the position of two machine parts which are displaceable relative to one another, in particular linearly. In this application too, a scanning element according to the invention with detector units arranged on both sides can be used. [Background technology]

[0004] WO 2019 / 185336 describes a scanning element with a transmitter coil and a sensor coil arranged on a multilayer printed circuit board, the printed circuit board having a layer configured as a shield. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 185336 Summary of the Invention [Problem to be solved by the invention]

[0006] The invention is based on the problem of creating a relatively precisely operating and cheaply manufacturable scanning element for an inductive position measuring device which allows the position determination of two scale elements. [Means for solving the problem]

[0007] This problem is solved according to the invention by the features of claim 1. The scanning element suitable for and determined for an inductive position measuring device comprises a multi-layer printed circuit board with a first detector unit and a second detector unit, and an electronic component. In particular, the first detector unit is arranged on a first side of the printed circuit board, and the second detector unit is arranged on a second side of the printed circuit board. The first detector unit has a first excitation line and a first receiving line. The second detector unit has a second excitation line and a second receiving line. Furthermore, the printed circuit board has a first shielding layer and a second shielding layer, and a geometric central plane, in particular centrally arranged between the first and second sides of the printed circuit board, the central plane being located between the detector units and the shielding layer. Furthermore, the multi-layer printed circuit board is configured such that the first detector unit is arranged on the first layer and the second layer, and the second detector unit is arranged on the third and fourth layers. The shielding layer is dimensioned such that an imaginary geometric first straight line penetrates or crosses both the first detector unit and the first shielding layer, while the second shielding layer is not penetrated by the first straight line. The first shielding layer is then disposed beyond the central plane, starting from the first detector unit. Also, an imaginary geometric second straight line penetrates or crosses both the second detector unit and the second shielding layer, while the first shielding layer is not penetrated by the second straight line. The second shielding layer is then disposed beyond the central plane, starting from the second detector unit. The first straight line and the second straight line are oriented in a direction perpendicular to the central plane.

[0008] The first straight line can cross or penetrate the first detector unit in the area of ​​the first excitation line or the area of ​​the first receiving line. The second straight line can cross or penetrate the second detector unit in the area of ​​the second excitation line or the area of ​​the second receiving line. The first excitation line and the second excitation line include excitation conductor paths that extend on different layers (i.e., the first layer, the second layer, the third layer, the fourth layer) of the printed circuit board. Similarly, the first receiving line and the second receiving line include receiving conductor paths that extend on the first layer, the second layer, the third layer, the fourth layer of the printed circuit board.

[0009] With regard to the definition of the spatial arrangement of the subject matter, a first direction x can first be defined. The first direction x represents the direction (measurement direction) along which the determined position is measured. The first direction x can, for example, be a circumferential or tangential direction. In this case, a position measurement in the first direction makes it possible to measure the angular position of the scale element relative to the scanning element with respect to a rotational or pivoting movement about a (rotational) axis. In the case of a linear position measurement, the first direction x runs along a linear measurement path.

[0010] Additionally, a second direction y can be defined that is orthogonal to the first direction x. A third direction z is oriented orthogonal to the first direction x and simultaneously orthogonal to the second direction y. For example, the third direction z may be parallel to an axis about which the scale element is rotatable relative to the scanning element. Furthermore, the third direction z is orthogonal to the central plane. The layers of the printed circuit board are offset from one another in the third direction z.

[0011] The central plane is located between the first detector unit and the first shield layer in the third direction z, or the first detector unit and the first shield layer are arranged on both sides of the central plane. It is therefore also possible that the central plane is located between the second detector unit and the second shield layer in the third direction z, and that the second detector unit and the second shield layer are arranged on both sides of the central plane.

[0012] Advantageously, the first shielding layer is disposed on the fifth layer of the printed circuit board and the second shielding layer is disposed on the sixth layer of the printed circuit board. Alternatively, the first shielding layer may be disposed on the first or second layer and the second shielding layer may be disposed on the third or fourth layer.

[0013] In a further aspect of the invention, the first excitation line and the second excitation line extend along a first direction x. In a second direction y, the first shield layer is offset by a first spacing relative to the second excitation line. Alternatively or complementary, the second shield layer is offset by a second spacing in a second direction relative to the first excitation line.

[0014] Advantageously, in a third direction oriented perpendicular to the central plane, the first detector unit is arranged offset a distance relative to the first shielding layer, the second spacing being greater than or equal to 25% of the distance and less than or equal to 100% of the distance. Alternatively or complementary, the second detector unit is arranged offset a distance relative to the second shielding layer, the first spacing being greater than or equal to 25% of the distance and less than or equal to 100% of the distance. Preferably, the second spacing is greater than or equal to 33% and less than or equal to 75% of the distance and / or the first spacing is greater than or equal to 33% and less than or equal to 75% of the distance.

[0015] Advantageously, the first and second receiving lines extend along a first direction x, the first receiving line being arranged with an offset relative to the second receiving line in a second direction y. In a further aspect of the invention, the scanning element is configured such that the first line or the second line passes through at least one of the electronic components. Alternatively, the first line and the second line can pass through one or more electronic components, particularly when electronic components are mounted on both sides of the printed circuit board.

[0016] Advantageously, the printed circuit board is configured such that the first straight line passes through the first receiving line of the first detector unit and / or the second straight line passes through the second receiving line of the second detector unit.

[0017] Advantageously, the first excitation line and the second excitation line extend along a first direction x, and the first excitation line is arranged relative to the second excitation line on the printed circuit board such that it overlaps in the second direction y. In other words, the areas of the first excitation line and the second excitation line overlap in the second direction y. In particular, the overlap may have a value of almost 100% such that the first excitation line is arranged with respect to the second excitation line without any substantial shift in the second direction y.

[0018] In a further aspect of the invention, the first detector unit has a third excitation line and the second detector unit has a fourth excitation line, the third excitation line being offset relative to the fourth excitation line in the second direction.

[0019] Advantageously, the scanning element is configured such that the first excitation line and the second excitation line are electrically connected in series. Advantageously, the first and second excitation wires can be energized with an excitation current (alternating or mixed current), which usually has a current intensity that varies over time. The excitation current can be generated by electronic components, i.e. its path can be formed by electronic components. Since there is a physical relationship between current intensity and voltage intensity, the same can of course be considered for the excitation voltage.

[0020] In a further embodiment of the invention, the signals generateable by the first and second receiving lines can be further processed, in particular by electronic components forming an evaluation circuit. That is to say, the electronic components may be elements of different electronic circuits or may be assigned to different circuits, for example, one electronic component may be a circuit element for generating an excitation current and a further electronic component may be a further circuit element for evaluating or further processing the signal.

[0021] According to a further aspect, the invention also includes an inductive position measuring device comprising a scanning element and first and second scale elements, the scale elements being arranged spaced apart on opposite sides of the printed circuit board in a third direction z (orthogonal to the central plane), and the scale elements may be arranged rotatably about a common axis relative to the scanning element.

[0022] Advantageous configurations of the invention emerge from the dependent claims. Further details and advantages of the scanning element according to the invention will become apparent from the following description of some embodiments with reference to the attached drawings. [Brief description of the drawings]

[0023] [Figure 1] 1 is a perspective view of a position measuring device including a scanning element, a first scale element and a second scale element. [Diagram 2] FIG. 2 is a plan view of a first side of a scanning element. [Diagram 3] FIG. 4 is a plan view of a second side of the scanning element. [Figure 4] FIG. 2 is a detailed cross-sectional view of a scanning element according to the first embodiment. [Diagram 5] FIG. 4 is a plan view of a first scale element. [Figure 6] FIG. 4 is a plan view of a second scale element. [Figure 7] FIG. 11 is a detailed cross-sectional view of a scanning element according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The invention is explained according to FIG. 1 with reference to a position measuring device with a scanning element 1 which can be used to determine both the angular position of a first scale element 2 and the angular position of a second scale element 3. The two scale elements 2, 3 are arranged rotatably about the axis R relative to the scanning element 1. Such a position measuring device can be used, for example, in a drive of a robot. The second scale element 3 is then non-rotatably connected, for example, to a drive shaft of a motor, which is in turn connected to a reducer with a driven shaft. Together with this the second scale element rotates. In this way, for example, an angular position for the commutation of a motor can be determined by means of the second scale element 3, and a relatively high-precision angular position for the positioning of a robot can be determined by means of the first scale element 2.

[0025] The scanning element 1, shown in plan view in Figures 2 and 3 respectively, comprises a printed circuit board 1.1 with several layers and electronic components 1.2 (Figure 3) mounted on the printed circuit board 1.1. The scanning element 1 is used for scanning a first scale element 2 and also for scanning a second scale element 3 at the same time. For this purpose, a first detector unit 1.11 is arranged on a first side of the printed circuit board 1.1 according to Figure 2 and a second detector unit 1.12 is arranged on a second side of the printed circuit board 1.1 according to Figure 3. In the present embodiment, the electronic components 1.2 are only mounted on the second side. However, alternatively or additionally, it is also possible to mount electronic components on the first side of the printed circuit board 1.1.

[0026] The first detector unit 1.11 includes a first excitation line 1.111, a first receiving line 1.112, a third excitation line 1.113, a third receiving line 1.114 and a fifth excitation line 1.115. The second detector unit 1.12 includes a second excitation line 1.121, a second receiving line 1.122, a fourth excitation line 1.123 and a fourth receiving line 1.124.

[0027] In FIG. 4, a schematic partial cross section through the scanning element 1 or through the printed circuit board 1.1 is shown, where for the sake of clarity the hatching of the electrically insulating material of the printed circuit board 1.1 has been omitted. Furthermore, the partial cross section of FIG. 4 is not drawn to scale in order to better illustrate the scanning element 1 according to the invention. As already mentioned above, the printed circuit board 1.1 has a multi-layer structure. From a geometrical perspective, a so-called central plane M can be defined for the printed circuit board 1.1, which is arranged parallel to the first side and parallel to the second side of the printed circuit board 1.1, respectively, in the center between the first and second side. Furthermore, the geometrical relationship of the individual elements to one another can be defined by means of a coordinate system, where the first direction x is the direction in which the position or angle measurement is to be performed as intended. In the present embodiment, the first direction x corresponds to the circumferential direction. The axis R about which the scale elements 2, 3 can be rotated runs parallel to a third direction z, which can also be defined here as the axial direction. A second direction y is oriented perpendicular to the third direction z and the first direction x, which can also be called radial in this embodiment (angular measurement). The plane formed by the x-axis and the y-axis is thus oriented parallel to the central plane M, and the third direction z and the axis R run perpendicular to the central plane M. A first detector unit 1.11 is arranged on the first layer A of the printed circuit board 1.1 and on the second layer B of the printed circuit board 1.1, while a second detector unit 1.12 is arranged on the third layer E and the fourth layer F. The first layer A is located closest to the first side of the printed circuit board 1.1, and the second layer B is located second closest to the first side of the printed circuit board 1.1. The same is true for the third layer E and the fourth layer F with respect to the second side of the printed circuit board 1.1.

[0028] The excitation lines 1.111, 1.113, 1.115 of the first detector unit 1.11 include excitation conductor paths 1.1111, 1.1131, 1.1151 which run on the first layer A and the second layer B. Similarly, the excitation lines 1.121, 1.123 of the second detector unit 1.12 include excitation conductor paths 1.1231, 1.1231 which run on the third layer E and the fourth layer F.

[0029] The excitation lines 1.111, 1.113, 1.115 of the first detector unit 1.11 surround the first receiving line 1.112 or the third receiving line 1.114. The second excitation line 1.121 and the fourth excitation line 1.123 of the second detector unit 1.12 surround the second receiving line 1.122 of the second detector unit 1.12. The fourth receiving line 1.124, which is also assigned to the second detector unit 1.12, is surrounded on one side by the fourth excitation line 1.123. Both the excitation lines 1.111, 1.121, 1.113, 1.115, 1.121, 1.123 and the receiving lines 1.112, 1.114, 1.122, 1.124 run along the first direction x.

[0030] The receiving lines 1.1121, 1.114, 1.122, 1.124 each include at least two receiving conductors 1.1121, 1.1141, 1.1221, 1.1241. Furthermore, the receiving conductors 1.1121, 1.1141 of the first detector unit 1.11 run with through holes on different layers of the printed circuit board 1.1, i.e. on the first layer A and the second layer B, so that undesired short circuits at the intersections are avoided. The same is true for the receiving conductors 1.1221, 1.1241 of the second detector unit 1.12, which run on the third layer E and the fourth layer F. The receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 have a spatially periodic path that is approximately sinusoidal or sinusoidal. In this embodiment, the receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 of one and the same receiving line 1.112, 1.114, 1.122, 1.124 are offset from one another by ¼ of a complete sine period (π / 2 or 90° along the first direction x). The receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 are electrically connected in such a way that they ultimately provide signals that are 90° out of phase with respect to position determination in the first direction x.

[0031] In this embodiment, the printed circuit board 1.1 also includes a fifth layer C and a sixth layer D. The sixth layer D includes a first shielding layer 1.13 and the fifth layer C includes a second shielding layer 1.14, where the shielding layers 1.13, 1.14 are relatively large copper layers that are partially interrupted or partially removed.

[0032] The first shield layer 1.13 is oriented parallel to the third direction z perpendicular to the central plane M and is dimensioned to generate a first straight line g1 that crosses or penetrates both the first detector unit 1.11 and the first shield layer 1.13, respectively. Furthermore, the first straight line g1 also penetrates the electronic component 1.2. However, at the same time, the second shield layer 1.14 is not penetrated by the first straight line g1. Furthermore, starting from the first detector unit 1.11, the first shield layer 1.13 is arranged beyond the central plane M, i.e. on the opposite side of the central plane M from the first detector unit 1.11.

[0033] Furthermore, the second shield layer 1.14 is oriented perpendicular to the central plane M and is dimensioned to generate a second straight line g2 that passes through both the second detector unit 1.12 and the second shield layer 1.14. The first shield layer 1.13 is not passed through by the second straight line g2. Starting from the second detector unit 1.12, the second shield layer 1.14 is disposed beyond the central plane M.

[0034] In particular, the printed circuit board 1.1 is arranged so that a first straight line g1 passes through the first receiving line 1.112 of the first detector unit 1.11 and a second straight line g2 passes through the second receiving line 1.122 of the second detector unit 1.12.

[0035] With the described arrangement, the first shielding layer 1.13 is arranged behind the first detector unit 1.11 (or offset towards the first detector unit 1.11 in the third direction z) by a distance t, where the distance t is greater than half the thickness of the printed circuit board 1. The same applies to the relative arrangement of the second shielding layer 1.14 with respect to the second detector unit 1.12. In the present example, the distance t is 2 mm and extends in the third direction z.

[0036] The first receiving line 1.112 is arranged with a shift Y in the second direction y relative to the second receiving line 1.122. In contrast to this, in this embodiment, the first excitation line 1.111 has no shift in the second direction y relative to the second excitation line 1.121, and therefore the first excitation line 1.111 is arranged on the printed circuit board 1.1 without any shift in the second direction y relative to the second excitation line 1.121.

[0037] In the second direction y, the first shield layer 1.13 does not extend to the second excitation line 1.121, and there is a first (radial) spacing a1 in the second direction y between the first shield layer 1.13 and the second excitation line 1.121. Similarly, there is a second spacing a2 in the second direction y between the second shield layer 1.14 and the first excitation line 1.111. Thus, the first shield layer 1.13 is offset from the second excitation line 1.121 by the first spacing a1, and the second shield layer 1.14 is offset from the first excitation line 1.111 by the second spacing a2. It has been shown that a high quality of the measurement signal and therefore an overall high measurement accuracy is obtained when the first interval a1 and / or the second interval a2 take values ​​between 25%·t and 100%·t (0.25·t≦a1≦1·t; 0.25·t≦a2≦1·t). In the present example, a1=a2.

[0038] In FIG. 5 the first scale element 2 is shown in plan view. In FIG. 6 the second scale element 3 is also shown in plan view. The scale elements 2, 3 each consist of a substrate, made of epoxy resin in the illustrated embodiment, on which two pitch lines 2.1, 2.2; 3.1, 3.2 are arranged. The pitch lines 2.1, 2.2; 3.1, 3.2 are arranged in the form of rings and are arranged on the substrate concentrically about an axis R with different diameters. The pitch lines 2.1, 2.2; 3.1, 3.2 each consist of a periodic sequence of alternating conductive pitch regions 2.11, 2.21; 3.11, 3.21 and non-conductive pitch regions 2.12, 2.22; 3.12, 3.22. The conductive pitch regions 2.11, 2.21; 3.11, 3.21 are made of copper, which is applied to the substrate in the illustrated embodiment. On the other hand, in the non-conductive pitch regions 2.12, 2.22; 3.12, 3.22 the substrate was not coated. By means of an arrangement with two pitch lines 2.1, 2.2; 3.1, 3.2 respectively the angular positions of the scale elements 2, 3 can be absolutely determined. The outermost pitch line 2.2 of the first scale element 2 has the greatest number of pitch regions 2.11, 2.21 along its circumference, which allows the greatest resolution for measuring the angular position.

[0039] In the assembled state according to Fig. 1, the scanning element 1 and the scale elements 2, 3 are opposed to each other with an axial distance or gap, so that in the case of a relative rotation between the scale elements 2, 3 and the scanning element 1 at the receiving conductors 1.1121, 1.1141, 1.1221, 1.1241, an inductive effect can generate signals that depend on the respective angular position. The prerequisite for generating a corresponding signal is that the excitation conductors 1.1111, 1.1131, 1.1141, 1.1211, 1.1231 each generate a time-varying electromagnetic excitation field in the area of ​​the scanned pitch structure. In the exemplary embodiment shown, the excitation conductors 1.1111, 1.1131, 1.1141, 1.1211, 1.1231 are designed as a number of planar parallel current-carrying individual conductors. The scanning element 1 comprises an electronic circuit with electronic components 1.2 that are electrically connected to each other via layers E, F. The electronic circuit may, for example, include an ASIC module. The electronic circuit of the scanning element 1 acts not only as an evaluation element, but also as an excitation control element, under whose control excitation currents are generated through the excitation conductors 1.1111, 1.1131, 1.1141, 1.1211, 1.1231. The excitation conductors 1.1111, 1.1131, 1.1141, 1.1211, 1.1231 are thus energized by one and the same excitation control element. Here, the first excitation line 1.111 and the second excitation line 1.121 are electrically connected in series.

[0040] When the excitation lines 1.111, 1.121, 1.113, 1.115, 1.121, 1.123 are energized, a cylindrically or cylindrically oriented electromagnetic field is generated around the excitation conductors 1.111, 1.1131, 1.1141, 1.1211, 1.1231. The magnetic field lines of the resulting electromagnetic field extend around the excitation lines 1.111, 1.121, 1.113, 1.115, 1.121, 1.123, the direction of the magnetic field lines depending in a known manner on the direction of the current in the excitation conductors 1.111, 1.1131, 1.1141, 1.1211, 1.1231. Eddy currents are induced in the conductive pitch regions 2.11, 2.21; 3.11, 3.21, whereby a modulation of the field depending on the angular position is achieved, respectively. Thus, by means of the receiving lines 1.112, 1.114, 1.122, 1.124, respectively, the relative angular position can be measured. A pair of receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 is arranged in the receiving lines 1.112, 1.114, 1.122, 1.124, respectively, so that they supply signals out of phase by 90°, so that the direction of rotation can also be determined. The signals generated by the receiving lines 1.112, 1.114, 1.122, 1.124 are further processed by a part of the electronics 1.2 forming an evaluation circuit.

[0041] Due to the special dimensions and arrangement of the first 1.13 and second 1.14 shielding layers, any adverse effect on the measurement accuracy of the two detector units 1.11, 1.12 can be largely prevented.

[0042] In particular, unacceptably high levels of crosstalk signals are prevented while at the same time excessive attenuation of the excitation field is avoided. Furthermore, electromagnetic interference of the detector units 1.11, 1.12 by the electronics 1.2 or from the outside is also prevented.

[0043] In Fig. 7 the configuration of a scanning element 1' according to a second embodiment is shown. The printed circuit board 1.1' of the second embodiment has only four layers A, B, C, D. In this embodiment the first shielding layer 1.13 is located on the third layer E and the second shielding layer 1.14 is located on the second layer B. Again the distance t' is substantially greater than half the thickness of the printed circuit board 1'.

[0044] Alternatively, it is also possible to arrange the first shielding layer 1.13 on the first layer A and / or the second shielding layer 1.14 on the fourth layer F.

Claims

1. A scanning element (1; 1') for an inductive position measuring device, comprising a multilayer printed circuit board (1.1; 1.1') and an electronic component (1.2), said printed circuit board (1.1; 1.1') comprises a first detector unit (1.11) and a second detector unit (1.12), said first detector unit (1.11) has a first excitation line (1.111) and a first receiving line (1.112), said second detector unit (1.12) has a second excitation line (1.121) and a second receiving line (1.122), said printed circuit board (1.1; 1.1') has a first shielding layer (1.13) and a second shielding layer (1.14) and a geometrical central plane (M) which is located between said first detector unit (1.11) and said second shielding layer (1.14) and said second detector unit (1.12) and said first shielding layer (1.13), and further said printed circuit board (1.1; 1.1') has said first detector units (1.11) are arranged on a first layer (A) and on a second layer (B); said second detector units (1.12) are adapted to be arranged in a third layer (E) and in a fourth layer (F); The first shielding layer (1.13) and the second shielding layer (1.14) a first straight line (g1) passes through both the first detector unit (1.11) and the first shielding layer (1.13), while the second shielding layer (1.14) is not passed through by the first straight line (g1), and the first shielding layer (1.13) is disposed beyond the central plane (M) starting from the first detector unit (1.11); a scanning element, the dimensions of which are such that a second straight line (g2) passes through both the second detector unit (1.12) and the second shielding layer (1.14), while the first shielding layer (1.13) is not passed through by the second straight line (g2), the second shielding layer (1.14) being located beyond the central plane (M) starting from the second detector unit (1.12), the first straight line (g1) and the second straight line (g2) being oriented in a direction perpendicular to the central plane (M).

2. 2. A scanning element (1;1') according to claim 1, wherein the first shielding layer (1.13) is arranged on a sixth layer (D) and the second shielding layer (1.14) is arranged on a fifth layer (C).

3. 2. A scanning element according to claim 1, wherein the first shielding layer (1.13) is arranged on the third layer (E) and the second shielding layer (1.14) is arranged on the second layer (B).

4. 4. A scanning element (1; 1') according to any one of claims 1 to 3, characterized in that in a third direction (z) perpendicular to the central plane (M) said first detector unit (1.11) is arranged at a distance (t; t') relative to said first shielding layer (1.13), said second spacing (a2) being greater than or equal to 25% of said distance (t; t') and less than or equal to 100% of said distance (t; t'), thus 0.25·t≦a2≦1·t or 0.25·t'≦a2≦1·t' is satisfied, and / or said second detector unit (1.12) is arranged at a distance (t; t') relative to said second shielding layer (1.14), said first spacing (a1) being greater than or equal to 25% of said distance (t; t') and less than or equal to 100% of said distance (t; t'), thus A scanning element in which 0.25·t≦a1≦1·t or 0.25·t'≦a1≦1·t' is satisfied.

5. 5. A scanning element (1;1') according to any one of claims 1 to 4, wherein the scanning element (1;1') is configured such that the first straight line (g1) and / or the second straight line (g2) passes through at least one of the electronic components (1.2).

6. A scanning element (1;1') according to any one of claims 1 to 5, wherein the printed circuit board (1.1;1.1') is configured such that the first straight line (g1) passes through the first receiving line (1.112) and / or the second straight line (g2) passes through the second receiving line (1.122).

7. A scanning element (1;1') according to any one of claims 1 to 6, wherein the first detector unit (1.11) has a third excitation line (1.113) and the second detector unit (1.12) has a fourth excitation line (1.123).

8. A scanning element (1;1') according to any one of claims 1 to 7, wherein the scanning element (1;1') is configured such that the first excitation line (1.111) and the second excitation line (1.121) are electrically connected in series.

9. A scanning element (1;1') according to any one of claims 1 to 8, wherein a time-varying excitation current is passed through the first excitation line (1.111) and the second excitation line (1.121), the excitation current being generateable by the electronic component (1.2).

10. A scanning element (1;1') according to any one of claims 1 to 9, wherein signals generateable by the first receiving line (1.112) and the second receiving line (1.122) can be further processed by the electronic component (1.2).

11. 11. An inductive position measuring device comprising a scanning element (1;1') according to any one of claims 1 to 10, and a first scale element (2) and a second scale element (3), the scale elements (2, 3) being arranged spaced apart on either side of the printed circuit board (1.1;1.1') in a third direction (z) oriented perpendicular to the central plane (M).

12. 12. An inductive position measuring device according to claim 11, wherein the scale elements (2, 3) are arranged rotatably about a common axis (R) relative to the scanning element (1; 1').

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