Print coil device

Abstract

A printed coil device comprising at least one printed coil (14) having a first electrical connection (40) and a second electrical connection (42), wherein the at least one printed coil (14) has a plurality of coil layers (20), and the coil layers (20) are spaced apart along an axis (18) of a successive sequence and follow one another with the numbering i=1, ..., n for the coil layers (20), where n is a natural number and is greater than or equal to three, and where the first electrical connection (40) is arranged on the coil layer (20) with the numbering i=1 and the second electrical connection (42) is arranged on the coil layer (20) with the numbering i=n / 2+1 if n is even, or on the coil layer (20) with the numbering i=(n-1) / 2+1 if n is odd, characterized in that the coil layers (20) each have a carrier (22), and electrical connections (48) between coil layers (20) are oriented transversely to the coil layers (20) and are designed as through-contacts of the carriers (22).

Description

[0001] The invention relates to a print coil device, comprising at least one print coil with a first electrical connection and with a second electrical connection, wherein the at least one print coil has a plurality of coil layers and the coil layers are spaced apart in an axis of a successive sequence and follow one another with the numbering i=1, ..., n for the coil layers, where n is a natural number and is greater than or equal to three, and wherein the first electrical connection is arranged at the coil layer with the numbering i=1 and the second electrical connection is arranged at the coil layer with the numbering i=n / 2+1 if n is even, or at the coil layer with the numbering i=(n-1) / 2+1 if n is odd.

[0002] A print coil device comprising a print coil with a first electrical connection and a second electrical connection is used, for example, in a sensor, in particular a proximity sensor, to determine an analog or digital position of a (metallic) target. In particular, such a print coil device is used in an inductive sensor.

[0003] US 2006 / 0 113 991 A1 discloses a proximity sensor comprising a core and a plurality of dielectric layers in a stacked configuration. A plurality of conductive paths are provided extending through the stacked layers, forming at least one coil.

[0004] DE 10 2011 088 394 A1 discloses a metal sensor having a first carrier substrate, a second carrier substrate, a first coil, a second coil and a magnetic field sensor, wherein the carrier substrates are formed as thin layers and arranged in a stack.

[0005] DE 39 25 926 A1 discloses an eddy current multilayer coil for generating high alternating magnetic fields.

[0006] DE 10 2012 220 275 A1 discloses an inductive proximity switch with an oscillator and a transmitter coil for generating an alternating magnetic field, a receiver circuit and two receiver coils operated in a differential circuit for detecting a metallic trigger penetrating the alternating magnetic field.

[0007] DE 103 59 885 B4 discloses an assembly for a switching device.

[0008] WO 2012 / 113 361 A1 discloses an inductive sensor with a coil arrangement which contains at least one excitation coil and at least one detection coil, wherein an electrical conductor is provided which is arranged in the excitation field of the at least one excitation coil and which has at least two regions in the circumferential direction of the excitation coil, each of which carries an eddy current in the presence of an excitation field.

[0009] In the article “Printed Inductors in RF Consumer Applications” by Stefan Stalf, IEEE Transactions on Consumer Electronics, Vol. 47, No. 3, August 2001, pages 426 - 435, an investigation of multilayer planar inductors is described.

[0010] The invention is based on the object of providing a print coil device which operates as trouble-free as possible with a large inductively effective area.

[0011] This object is achieved according to the invention in the print coil device mentioned at the outset in that the coil layers each have a carrier and electrical connections between coil layers are oriented transversely to the coil layers and are designed as through-contacts of the carriers.

[0012] The solution according to the invention makes it possible to achieve a meandering, interlaced pattern of conductor elements of coil layers of the at least one printed coil. In particular, a type of spiral arrangement can be achieved with respect to the entire printed coil.

[0013] This prevents induction voltages from accumulating at individual coil layers. This, in turn, keeps parasitic capacitive currents low.

[0014] This results in a high level of measurement accuracy for an application.

[0015] Furthermore, a large number of thermal connections can be established between coil layers (in particular, n thermal connections are present). This enables optimized temperature compensation and minimizes temperature gradients across the printed coil as a whole, particularly in the direction of the axis of successive stacking. This contributes to increasing measurement accuracy.

[0016] In particular, a gradiometric or kind of symmetrical design can be achieved on the print coil device if n is even.

[0017] In particular, it is intended that n be greater than or equal to four, and that n may, in particular, be even. This allows a type of symmetric gradiometer to be easily constructed.

[0018] In particular, it is proposed that a coil layer numbered i, when i ≤ n / 2, be electrically connected to a coil layer numbered n+1-i. This effectively reduces temperature gradients. Furthermore, parasitic capacitive currents can be effectively reduced.

[0019] For the same reason, it is advantageous if a coil layer with numbering i at i ≥ n / 2+1 is electrically connected to a coil layer with numbering n-i+2.

[0020] Electrical connections between coil layers are oriented transversely to the coil layers and are designed as through-holes. This allows for the realization of a printed coil device with ease of manufacture and spatial compactness, allowing high measurement accuracy due to reduced susceptibility to interference.

[0021] It is particularly advantageous if the conductor path of an electrical connection is at least approximately parallel to the axis of the successive sequence. This allows for easy production of vias, particularly as through-hole platings.

[0022] It is particularly advantageous if an electrical connection also serves as a thermal connection between coil layers, and if n such thermal connections are present. This effectively reduces temperature gradients and achieves good temperature uniformity across all coil layers. This, in turn, allows for greater measurement accuracy with reduced susceptibility to interference.

[0023] In particular, a thermal connection (via) exists between the coil layer numbered i=1 and the coil layer numbered i=n. Thus, a thermal connection exists between the two outermost coil layers. This effectively reduces thermal temperature gradients.

[0024] Conveniently, a coil layer comprises a carrier on which a conductor track is arranged, extending between a first conductor track connection and a second conductor track connection. Coil layers can be electrically connected to one another via the conductor track connections to form the printed coil. The carrier is made, for example, of a composite material such as a fiber-reinforced resin material. This allows for easy production of printed coil layers.

[0025] It is particularly advantageous if the conductor track between the first conductor track connection and the second conductor track connection is spiral-shaped. This allows for high surface coverage with conductor tracks and effectively generates large magnetic fields.

[0026] It is advantageous if the first conductor connection is arranged on an outer side of the conductor track and the second conductor connection is arranged on an inner side of the conductor track, with the inner side being closer to a spiral axis than the outer side. This allows the printed coil to be formed easily and allows coil layers to be electrically connected to one another in an effective and simple manner. An electrical connection between coil layers can be achieved over essentially the entire length of the axis of the successive sequence, for example, via vias.

[0027] In particular, it is then provided that the electrical connections run (only) between first conductor track connections of connected coil layers and (only) between second conductor track connections of connected coil layers. This results in simple cable routing between first conductor track connections and between second conductor track connections for corresponding electrical connections. These can be easily implemented, in particular parallel to the axis of the successive sequence. Vias as electrical connections can thus be easily created, for example, via through-hole plating.

[0028] In particular, it is provided that coil layers are spaced parallel, and the distance between coil layers numbered i and i+1 (i.e., adjacent coil layers) is equal to the distance between corresponding coil layers numbered n-i+1 and ni (i.e., also adjacent coil layers). Thus, the distances are equal from the outside to the inside (i.e., starting from the coil layer numbered i=1 and starting from the coil layer numbered i=n).

[0029] In particular, it is provided that the coil layers numbered i=1 to i=n / 2 are spaced parallel and have the same first distance from one another. In particular, these coil layers have a common coil axis (winding axis and, in particular, spiral axis). This allows for high surface coverage with ease of manufacture. Furthermore, an anti-serial arrangement can be easily achieved.

[0030] For the same reason, it is advantageous if the coil layers numbered i=n / 2 to i=n are spaced parallel and have the same second distance from each other.

[0031] A gradiometer can be easily implemented if the second distance is equal to the first distance between coil layers numbered i=1 to i=n / 2. The printed coil then essentially has two separate coil layer stacks, which can be arranged symmetrically or antisymmetrically. This allows a simple gradiometer to be constructed.

[0032] It is particularly advantageous if there is a first coil layer package with coil layers numbered i=1 to i=n / 2 and a second coil layer package with coil layers numbered i=n / 2+1 to i=n, whereby no coil layer of the first coil layer package is directly electrically connected to another coil layer of the first coil layer package and no coil layer of the second coil layer package is directly electrically connected to another coil layer of the second coil layer package. This makes it possible to effectively reduce parasitic capacitive currents. Thermal gradients across the at least one printed coil can be kept low. This results in a simple, compact design with a large area coverage with regard to conductor tracks for generating a magnetic field.

[0033] In particular, coil layers of the first coil layer package are then directly electrically connected to coil layers of the second coil layer package or coil layers of the second coil layer package are directly electrically connected to coil layers of the first coil layer package.

[0034] In one embodiment, at least one further coil, particularly in the form of a printed coil, is arranged between the first coil layer stack and the second coil layer stack, or a center tap is arranged. In particular, the at least one further coil is arranged symmetrically with respect to the first coil layer stack and the second coil layer stack. For example, the at least one further coil can thus be easily implemented as a transmitting coil, and the printed coil with the first coil layer stack and the second coil layer stack forms a receiving coil device in an antisymmetrical arrangement.

[0035] For example, a bridge circuit can be realized using a center tap.

[0036] It can be provided that the at least one further coil has a third terminal and a fourth terminal. This third terminal and the fourth terminal are arranged, in particular, on the same side of a coil body as the first terminal and the second terminal, so that the printed coil device can be easily connected to an application. Alternatively or additionally, it is possible for a connection to be established via a press-fitted pin on a via.

[0037] It can be provided that the at least one additional coil has a plurality of coil layers, which are connected in series with one another, in particular, to form the at least one additional coil. This allows for high surface coverage.

[0038] As already mentioned, it can be provided that the at least one further coil is designed as a transmitting coil, and the printed coil forms a receiving coil arrangement, to which the at least one further coil is arranged and / or connected, in particular symmetrically. For example, the transmitting coil then inductively couples to a target, and the target inductively couples to the receiving coil device, with the position of the target influencing this coupling. From this, the position of the target can be determined.

[0039] It is particularly advantageous if a conductor guide for current transport through the at least one printed coil is provided which has a spiral shape when a conductor guide through the respective coil layer is viewed in an equivalent circuit diagram as a straight conductor path between a first conductor track connection of the respective coil layer and a second conductor track connection of the respective coil layer. The conductor guide at the individual coil layers can also be spiral, wherein in particular a spiral axis of the conductor guide for current transport through the entire at least one printed coil lies transversely to the axis of the successive sequence. Such a spiral shape of the conductor guide effectively allows parasitic capacitive currents to be kept low. Furthermore, temperature gradients across the at least one printed coil in the axis of the successive sequence can be kept low.

[0040] As mentioned, it is advantageous if a spiral axis for the conductor guidance is oriented transversely to the axis of the successive sequence of the coil layers in order to achieve the described advantages.

[0041] Advantageously, the at least one printed coil corresponds to an anti-serial arrangement of two individual coils, with components of these individual coils then being nested within each other.

[0042] It is particularly advantageous if the axis of the successive coil layers is oriented perpendicular to the coil layers, and especially perpendicular to the coil layer supports. This allows for high surface coverage at the individual coil layers and results in a compact multi-layer structure.

[0043] For the same reason, it is advantageous if the axis of the successive sequence of coil layers is oriented parallel or coaxial to a coil axis (winding axis) of the coil layers.

[0044] Advantageously, the at least one print coil is assigned a target having a motion component along an axis, wherein this axis is coaxial or parallel and / or transverse to the axis of the successive sequence of coil layers. This effectively provides a gradiometer for determining the position of the target, particularly in an analog or digital manner.

[0045] In particular, the coil body has a top side on which the first terminal and the second terminal are arranged, and advantageously also at least one additional terminal and at least one additional coil are arranged. This results in a compact design with easy connection to an application.

[0046] According to the invention, a print coil device is provided which comprises at least one print coil with a plurality of coil layers, in which a shielding device for an electric field surrounds the coil layers in a sleeve-like manner.

[0047] The shielding device forms a kind of shielding cage for the coil layers.

[0048] This print coil device can be provided in particular according to the invention in connection with the electrical connection between coil layers described above.

[0049] The shielding device can effectively reduce capacitive interference from outside.

[0050] The shielding device primarily shields against external electric fields. It forms a type of Faraday cage. It is permeable to static or quasi-static magnetic fields, allowing for effective inductive coupling to a target.

[0051] When appropriately designed, this Faraday cage is also permeable to alternating magnetic fields. For this purpose, the conductor thickness is specifically designed to be significantly thinner than the electromagnetic penetration depth.

[0052] In one embodiment, the shielding device comprises a plurality of spaced-apart current conducting paths arranged at least approximately parallel to an axis of a successive sequence of coil layers and / or at least approximately parallel to coil axes of the coil layers. This allows a sleeve-shaped shielding device to be easily realized.

[0053] In particular, these current conducting paths are then located on an envelope sheath, which surrounds the coil layers in a sleeve-like manner.

[0054] It is preferably provided that at least one current conduction path is electrically connected to a terminal of the at least one printed coil and / or another coil. This allows for effective shielding.

[0055] Advantageously, a current-conducting network is provided, which is assigned to a top and / or bottom side of one of the coil bodies. This allows for a type of cover for a sleeve-shaped shielding device, which effectively reduces the interference of electric fields via the top or bottom side.

[0056] In particular, training as a gradiometer is planned.

[0057] A print coil device according to the invention can be used in particular as a sensor element of a proximity sensor or distance sensor and in particular of an inductive proximity sensor or distance sensor.

[0058] According to the invention, a proximity sensor or distance sensor, and in particular an inductive proximity sensor or distance sensor, is provided, comprising at least one print coil device according to the invention.

[0059] An inductive proximity sensor or distance sensor can detect metallic objects as they approach without contact. It typically consists of an oscillator and an evaluation unit. The oscillator is caused to oscillate, and an approaching target can extract energy from the oscillating circuit. This can be measured, for example, as a reduction in the oscillator voltage.

[0060] The following description of preferred embodiments, in conjunction with the drawings, serves to further explain the invention. They show: Fig. 1 a side view of an embodiment of a print coil device according to the invention; Fig. 2 a plan view of the print coil device according to Fig. 1 in direction A; Fig. 3 schematically shows a structure of the print coil device according to Fig. 1 regarding a ladder guide; Fig. 4 a similar view to Fig. 3 with an electromagnetic shield; Fig. 5 a perspective view of a coil layer according to the section along the line 5-5 according to Fig. 1; Fig. 6 a perspective view of the print coil device according to Fig. 1 in direction A (according to the view according to Fig. 2), where the electrical circuit is shown; Fig. 7 a view of a bottom side of the print coil device according to Fig. 1 in direction B according to Fig. 1, showing the electrical structure; Fig. 8 a sectional view of the coil layer arrangement in the print coil device according to Fig. 1 in line 8-0-8 according to Fig. 2; Fig. 9 a perspective partial sectional view of the print coil device according to Fig. 1 showing the coil positions; Fig. 10 a similar view to Fig. 9; Fig. 11 is a schematic sectional view of an embodiment of a sensor (inductive proximity sensor) with a printed coil device according to the invention; and Fig. 12 a schematic sectional view of another embodiment of a print coil device according to the invention.

[0061] An embodiment of a print coil device 10 according to the invention ( Fig. 1, Fig. 2) comprises a coil former 12. At least one printed coil 14 is arranged on the coil former. In one embodiment, in addition to the printed coil 14, a further coil 16 in the form of a printed coil is positioned on the coil former 12.

[0062] In one embodiment, the coil body 12 is at least approximately cylindrical with an axis 18 ( Fig. 1). The axis 18 forms an axial axis for the coil body 12 and also the printed coil device 10.

[0063] The print coil device 10 comprises a plurality of coil layers 20. A coil layer 20 comprises a carrier 22 (see Fig. 5), on which a conductor track 24 is arranged. The conductor track 24 extends between a first conductor track connection 26 and a second conductor track connection 28.

[0064] The conductor track 24 is arranged as a printed circuit track on the carrier 22. A coil layer 20 is, for example, a PCB coil layer (Printed Circuit Board coil layer).

[0065] The conductor track 24 between the first conductor track connection 26 and the second conductor track connection 28 is in particular spirally guided with a spiral axis 30. The spiral axis 30 forms a coil axis 32.

[0066] The coil layers 20 on the coil body 12 are arranged such that the spiral axes 30 of each coil layer 20 (and thus the coil axis 32 of the printed coil 14) are coaxial with the axis 18.

[0067] The first conductor track connection 26 is located on an outer side with respect to the spiral axis 30, and the second conductor track connection 28 is located on an inner side with respect to the spiral axis 30; the second conductor track connection 28 is closer to the spiral axis 30 than the first conductor track connection 26.

[0068] The conductor track 24 is arranged, for example, in the form of an Archimedean spiral.

[0069] The support 22 is designed in the manner of a flat plate.

[0070] The coil layers 20 follow one another in a direction 34 along the axis 18; the axis 18 is an axis of a successive sequence of coil layers 20, each with a carrier 22 and a conductor track 24.

[0071] The coil layers 20 are numbered with i={1, ..., n}.

[0072] The coil former 12 has a top side 36. It has an opposite bottom side 38. The coil layer 20 closest to the top side 36 has the number i=1. The coil layer 20 closest to the bottom side 38 has the number i=n.

[0073] n indicates the number of coil layers 20; n is an even natural number greater than or equal to four.

[0074] In the Fig. 3, n=10. In the example shown in Fig. 8, n=6. In the embodiment shown in the Fig. 9, Fig. In the embodiment shown in Figure 10, n=10.

[0075] All coil layers 20 are oriented parallel to each other. A normal of their carrier 22 and a corresponding spiral axis 30 are coaxial with the axis 18 of the successive sequence. The sum of all coil layers 20 forms the printed coil 14.

[0076] The print coil 14 has a first terminal 40 and a second terminal 42.

[0077] In one embodiment, the first terminal 40 and the second terminal 42 are arranged on the top side 36 of the coil former 12. This provides easy accessibility.

[0078] The first terminal 40 is directly connected to the coil layer 20 with the numbering i=1. The second terminal 42 is connected to the coil layer with the numbering i=n / 2+1. The printed coil device 10 can be connected to an application at the terminals 40, 42, for example, to form an oscillating circuit of a sensor.

[0079] The printed coil 14 comprises a first coil layer package 44 and a second coil layer package 46. The first coil layer package 44 is formed by the coil layers 20 numbered i=1 to n / 2. The second coil layer package 46 is formed by the coil layers 20 numbered i=n / 2+1 to n.

[0080] The coil layers 20 of the first coil layer package 44 are arranged parallel to one another, wherein in one embodiment adjacent coil layers 20 of the first coil layer package 44 are spaced apart by a uniform distance A1 in the axis 18.

[0081] The coil layers 20 of the second coil layer stack 46 are aligned parallel and spaced apart in one embodiment by a uniform spacing A2. The spacing A1 of the coil layers 20 of the first coil layer stack 44 and the spacing A2 of the coil layers 20 of the second coil layer stack 46 are identical.

[0082] In principle, the spacing between adjacent coil layers 20 is intended to be equal from the outside to the inside. This means that the spacing between adjacent coil layers 20 numbered i and i+1 is equal to the spacing between adjacent coil layers numbered n-i+1 and ni. This is especially true when n is even.

[0083] The distance between the first coil layer stack 44 and the second coil layer stack 46 (corresponding to the distance between the coil layer 20 with the numbering i=n / 2 and the coil layer 20 with the numbering i=n / 2+1) does not have to correspond to the distance A1 or A2. In particular, it can be greater than the corresponding distance.

[0084] In one embodiment, the further coil 16 is arranged between the first coil layer package 44 and the second coil layer package 46.

[0085] To form the printed coil 14, the conductor tracks 40 of the respective coil layers 20 are connected to electrical connections 48, which are oriented transversely to the respective coil layer 20 and, in particular, are oriented perpendicularly (parallel to the axis 18). These electrical connections are formed, for example, by vias 50 ( Fig. 8) was formed.

[0086] The electrical connections 48 or vias 50 are designed such that the coil layer i with i={1, ..., n / 2} is electrically connected to the coil layer 20 with the numbering n+1-i.

[0087] The coil layer with the numbering i={n / 2+1, ..., n} is directly electrically connected to the coil layer 20 with the numbering n-i+2.

[0088] This connecting run is in Fig. 3, wherein the conductor track 24, which is in particular spiral-shaped, is shown in a side view.

[0089] Consequently, no coil layer 20 of the first coil layer package 44 is directly connected to another coil layer 20 of the first coil layer package 44, but first conductor track connections 26 or second conductor track connections 28 of coil layers 20 of the first coil layer package 44 are only connected to corresponding conductor track connections of coil layers 20 of the second coil layer package 46.

[0090] Accordingly, corresponding conductor track connections 26, 28 of the second coil layer package 46 are not connected to coil layers 20 of the second coil layer package 46, but only to corresponding conductor track connections 26, 28 of the first coil layer package 44.

[0091] The connection between coil layers 20 of the first coil layer package 44 and the second coil layer package 46 is such that when coil layers 20 are connected, the corresponding first conductor track connection 26 is connected to the associated other first conductor track connection 26, and the corresponding second conductor track connection 28 is connected to the associated second conductor track connection 28.

[0092] This allows the vias 50 (the electrical connections 48) to be formed at least approximately parallel to the axis 18 (or parallel to the spiral axes 30 or parallel to the coil axis 32).

[0093] The electrical connections 48 can then be easily established via through-holes.

[0094] In an equivalent circuit diagram ( Fig. 3), in which the conductor track 24 is viewed as a straight conductor path, or in a side view, the conductor path of the printed coil 14 has a spiral shape due to the corresponding connections of the coil layers 20 of the first coil layer stack 44 with the second coil layer stack 46. An associated spiral axis 52 is perpendicular to the axis 18 of the successive sequence of the coil layers 20 with i={1, ..., n}. The spiral axis 52 lies between the first coil layer stack 44 and the second coil layer stack 46.

[0095] The first terminal 40 of the printed coil 14 is at the same potential as the first conductor track terminal 26 of the coil layer 20 with the numbering i=1.

[0096] The second terminal 42 of the printed coil 14 is at the same potential as the first conductor track terminal 26 of the coil layer 20 with the numbering i=n / 2+1.

[0097] The coil layers 20 are identical in terms of their electrical properties. During operation in the context of an application, a voltage U is applied to a coil layer 20 between the first conductor connection 26 and the second conductor connection 28. ind The connection of the coil layers 20 of the first coil layer package 44 with the coil layers 20 of the second coil layer package 46 is such that these voltages U ind cannot accumulate in a coil pack 44 or 46. This greatly reduces the risk of capacitive cross currents occurring; voltage differences between corresponding conductor track connections 26, 28 of adjacent coil layers 20 are avoided.

[0098] This reduces external capacitive interference. The influence of parasitic capacitive currents is reduced, as these parasitic capacitive currents are fundamentally reduced.

[0099] Furthermore, this also reduces gradient sensitivity to temperature differences. By connecting coil layers 20 of the first coil layer stack 44 with coil layers 20 of the second coil layer stack 46, which also serve as thermal connections, improved temperature compensation is achieved across the printed coil device 10 as a whole relative to the axis 18.

[0100] The vias 50 represent thermal connections, with n vias 50 and thus n thermal connections being present, which enable effective temperature equalization along the axis 18 and thus the reduction of temperature gradients.

[0101] (If the printed coil 14 were formed by a simple serial connection of coils, only n / 2 thermal connections would be present.)

[0102] Furthermore, the thermal connections extend over an entire length of the printed coil 14 relative to the axis 18; thus, the coil layer 20 with the numbering i=1 is connected to the coil layer 20 with the numbering i=n; this establishes a thermal connection from the top side 36 to the bottom side 38.

[0103] The printed coil 14 has a double spiral structure. In the respective coil layers 20, the conductor tracks 24 are spirally formed and arranged with spiral axes 30. The coil layers 20 are arranged spirally with respect to the conductor routing, with a spiral axis 52 perpendicular to the spiral axis 30.

[0104] The printed coil 14 can be regarded as an antisymmetrical serial circuit of two individual coils, whereby these individual coils are nested within each other.

[0105] In one embodiment, the additional coil 16 (which may in particular comprise a plurality of coil layers) forms a transmitting coil 54 that emits transmission signals. A typical frequency for such transmission signals is, for example, 400 kHz.

[0106] The print coil 14 forms a receiving coil device.

[0107] A target 56 made of a metallic material is provided. The target 56 has, in particular, a movement component 58 parallel (and / or perpendicular) to the axis 18 of the successive sequence of coil layers 20.

[0108] The position of the target 56 on the movement axis 58 influences the coupling to the receiving coil device 14. If the target is not positioned symmetrically with respect to the first coil layer stack 44 and the second coil layer stack 46, then these two coil layer stacks 44, 46 are influenced differently. The position of the target 56 can be determined from this different influence.

[0109] In this example, the print coil device 10 forms a gradiometer or part of a gradiometer. The target 56, when arranged asymmetrically, creates a gradient field.

[0110] The coupling of the target 56 to the print coil device 10 with print coil 14 (receiving coil device) and transmitting coil 54 is inductive.

[0111] In one embodiment (compare Fig. 4) an electromagnetic shielding device 60 is arranged on the print coil device 10, which in particular surrounds the print coil 14 (and optionally the further coil 16) in a sleeve-like manner.

[0112] The electromagnetic shielding device 60 forms a type of Faraday cage and serves, in particular, to shield the print coil 14 (and also the transmitting coil 54) from electric fields. The electromagnetic shielding device 60 is permeable to static or quasi-static magnetic fields, thus enabling inductive coupling between the target 56 and the print coil device 10.

[0113] In one embodiment, a third terminal 62 and a fourth terminal 64 for the further coil 16 are arranged on the top side 36.

[0114] It is also fundamentally possible to arrange, for example, a center connection between the first coil layer stack 44 and the second coil layer stack 46 instead of an additional coil 16. This allows, for example, a bridge circuit to be created with the printed coil device 10.

[0115] To form the electromagnetic shielding device 60, in one embodiment, recesses 66 are arranged on the coil body 12 between the upper side 36 and the lower side 38, in which a current conducting path 68 (cf. Fig. 5 to 7). Such a current conducting path 68 runs between the top side 36 and the bottom side 38.

[0116] A plurality of spaced current conducting paths 68 are arranged, which are aligned parallel to the axis 18 and lie on an envelope shell 70 of the coil former 12. The sum of these current conducting paths 68 accordingly forms a shell of the sleeve-shaped arrangement of the electromagnetic shielding device 60.

[0117] In the region of the upper side 36, a current conducting network 72 is arranged, which forms a type of cover on the upper side 36 for the sleeve-shaped electromagnetic shielding device 60. This current conducting network 72 is connected in particular to a terminal and, for example, to the first terminal 40.

[0118] Accordingly, a current conducting network 74 is arranged in the area of the underside 38, which forms a cover for the sleeve-shaped electromagnetic shielding device 60 in the area of the underside 38.

[0119] This current conduction network 74 is in particular electrically connected to the current conduction paths 68.

[0120] In one embodiment, a single current conducting path 68 (in Fig. 6 designated 68') is connected to the first terminal 40. This is the only current conducting path of the current conducting paths 68 which is connected.

[0121] This current conduction path 68' is also connected to the current conduction network 72.

[0122] On the underside 38 (compare Fig. 7) all current conducting paths 68 are electrically connected to the current conducting network 74.

[0123] The electrical connections 48 are electrically separated from the power grid 72, the power grid 74 and the power paths 78.

[0124] In Fig. 8 is schematically shown in section line 8-0-8 according to Fig. 2 the structure of the printed coil 14 in connection with n=6 coil layers 20 is shown.

[0125] The connection of the coil layers 20 is as described above from the first coil layer package 44 to the second coil layer package 46.

[0126] The electrical connections 48 via vias 50 are such that, in particular, the coil layer with the numbering i=1 is connected to the coil layer with the numbering i=6(=n). This coil layer with i=6 is then in turn connected to the coil layer with the numbering i=2. The coil layer with the numbering i=2 is then in turn connected to the coil layer 20 with the numbering i=5. The coil layer with the numbering i=5 is connected to the coil layer with the numbering i=3. The coil layer with the numbering i=3 is connected to the coil layer with the numbering i=4 (in Fig. 8 not shown).

[0127] This results in Fig. 8 with the reference number 76 indicated current guide, which has a spiral course with respect to a sectional plane in which the axis 18 lies.

[0128] In the Fig. 9 and Fig. 10 shows concrete examples of implementation.

[0129] The corresponding print coil 14 is basically designed the same as described above.

[0130] The further coil 16 comprises a plurality of coil layers 78 which are arranged in parallel and are aligned in particular parallel to coil layers 20 of the print coil 14.

[0131] In each coil layer 78, a spiral conductor track is arranged on a carrier, wherein in particular a coil axis coincides with the coil axis 32.

[0132] In principle, the coil layers 78 can be designed in the same way as the coil layers 20, or they can be different, for example, with regard to coil diameter, number of turns, spacing, and width.

[0133] The conductor tracks 24 of the coil layers 78 are preferably connected in series.

[0134] The supports 22 of the coil layers 20 and also of the coil layers 78 are made of an electrically insulating material, for example, a composite material. This composite material comprises, for example, a fabric-reinforced (and in particular, glass-fabric-reinforced) resin material. The conductor tracks 24 and also the conductor tracks of the coil layers 78 are manufactured, for example, using PCB processes, LTCC processes, or a semiconductor process.

[0135] The electrical connections 48 (vias 50) and also the current conducting paths 68 are made in particular via through-hole platings.

[0136] According to the invention, a printed coil device is provided which, due to the electrical connection of the coil layers 20 between the first coil layer stack 44 and the second coil layer stack 46, exhibits low external capacitive interference. Furthermore, the influences of parasitic capacitive currents can be kept low, since such parasitic capacitive currents are difficult to form.

[0137] Furthermore, the gradient sensitivity in temperature is improved because the electrical connections 48 also represent thermal connections.

[0138] The electromagnetic shielding device 60 forms a shielding cage that surrounds the coil layers 20 in a sleeve-like manner. This reduces the capacitive interference from electromagnetic fields.

[0139] A large coil area can be provided with low capacitive interference susceptibility (with low E-field influence).

[0140] The print coil device 10 can be used in particular in conjunction with a gradiometric sensor device.

[0141] The solution according to the invention can also be implemented on a printed coil device in which the number n of coil layers 20 is odd. In this case, in particular, a first connection is provided at the coil layer numbered i=1, and a second connection of the printed coil device is provided at the coil layer numbered i=(n-1) / 2+1. The same advantages regarding insensitivity to capacitive fault currents and reduced thermal gradient sensitivity can be achieved.

[0142] In Fig. Figure 12 shows a schematic sectional view of a printed coil device with an odd number n (here n=5) of coil layers 100. The sectional view is such that the course of the connections between the coil layers is visible.

[0143] A first terminal 40 is arranged at a first coil layer (with i=1). A current conducting path 102 leads from this first coil layer with i=1 to the coil layer with i=5. A current conducting path 104 leads from this coil layer with i=5 to the coil layer with i=2.

[0144] A current conducting path 106 leads from the coil position with i=2 to the coil position with i=4.

[0145] A current conducting path 108 leads from the coil position with i=4 to the coil position with i=3.

[0146] The second terminal 42 is arranged in the coil position with i=3.

[0147] The cut in Fig. 12 is chosen in such a way that this course of the current conducting paths 102, 104, 106, 108 is visible.

[0148] A printed coil device 110 with core 112 formed by the coil layers 100 and the current conducting paths 102, 104, 106, 108 functions in principle the same way as described above.

[0149] In Fig. Figure 11 schematically shows a sectional view of an embodiment of a sensor 80. The sensor 80 comprises a housing 82. A connection piece 84 is arranged on the housing. This connection piece 84 can accommodate an electrical connection.

[0150] On a side opposite the connection piece 84, the housing 82 is closed by a cap 86, in particular made of a plastic material.

[0151] In an interior space 88 of the housing 82 and in an interior space 90 of the cap 86, a print coil device 10 according to the invention is positioned as a sensor element.

[0152] This is, in particular, mechanically connected to one or more printed circuit boards 92. An evaluation unit of the sensor 80 is located on the printed circuit board(s).

[0153] The interior space 90 is in particular filled with a filler such as a foam material or a potting material.

[0154] The sensor 80 is in particular an (analog or digital) inductive proximity sensor or distance sensor. List of reference symbols 10 Print coil device 12 coil bodies 14 Print coil, receiving coil device 16 Additional coil 18 Axis of successive succession 20 coil layers 22 carriers 24 conductor tracks 26 First conductor connection 28 Second conductor connection 30 spiral axis 32 Coil axis 34 direction 36 Top 38 Bottom 40 First connection 42 Second connection 44 First coil layer package 46 Second coil layer package 48 Electrical connection 50 Via 52 spiral axis 54 transmitting coil 56 Target 58 Movement component 60 Electromagnetic shielding device 62 Third connection 64 Fourth connection 66 recess 68 current conduction path 68' power line path 70 Envelope coat 72 Power grid 74 Power grid 76 Power supply 78 coil position 80 sensors 82 housings 84 connecting pieces 86 cap 88 Interior 90 interior 92 circuit boards 100 coil layers 102 current conduction path 104 Current conduction path 106 current conduction path 108 current conduction path 110 Print coil device 112 core

Claims

[1] A printed coil device comprising at least one printed coil (14) having a first electrical connection (40) and a second electrical connection (42), wherein the at least one printed coil (14) has a plurality of coil layers (20), and the coil layers (20) are spaced apart in an axis (18) of a successive sequence and follow one another with the numbering i=1, ..., n for the coil layers (20), where n is a natural number and is greater than or equal to three, and wherein the first electrical connection (40) is arranged at the coil layer (20) with the numbering i=1 and the second electrical connection (42) is arranged at the coil layer (20) with the numbering i=n / 2+1 if n is even, or at the coil layer (20) with the numbering i=(n-1) / 2+1 if n is odd, characterized bythat the coil layers (20) each have a carrier (22), and electrical connections (48) between coil layers (20) are oriented transversely to the coil layers (20) and are designed as through-contacts of the carriers (22). [2] Print coil device according to claim 1, characterized by that n is even. [3] Print coil device according to claim 1 or 2, characterized by that n is greater than or equal to four. [4] Print coil device according to one of the preceding claims, characterized by that a coil layer (20) with the numbering i at i ≤ n / 2 is electrically connected to a coil layer (20) with the numbering n+1-i. [5] Print coil device according to one of the preceding claims, characterized by that a coil layer (20) with the numbering i at i ≥ n / 2+1 is electrically connected to a coil layer (20) with the numbering n-i+2. [6] Print coil device according to one of the preceding claims, characterized bythat a conductor path of an electrical connection (48) is at least approximately parallel to the axis (18) of the successive sequence. [7] Print coil device according to one of the preceding claims, characterized by that an electrical connection (48) is also a thermal connection between coil layers (20) and n such thermal connections are present. [8] Print coil device according to claim 7, characterized by that there is a thermal connection between the coil layer (20) with the numbering i=1 and the coil layer (20) with the numbering i=n. [9] Print coil device according to one of the preceding claims, characterized by that a conductor track (24) is arranged on the carrier (22), which extends between a first conductor track connection (26) and a second conductor track connection (28). [10] Print coil device according to claim 9, characterized bythat the conductor track (24) between the first conductor track connection (26) and the second conductor track connection (28) is spiral-shaped. [11] Print coil device according to claim 10, characterized by that the first conductor track connection (26) is arranged on an outer side of the conductor track (24) and the second conductor track connection (28) is arranged on an inner side of the conductor track (24), wherein the inner side is closer to a spiral axis (30) than the outer side. [12] Print coil device according to one of claims 7 to 11, characterized by that electrical connections (48) run between first conductor track connections (26) of connected coil layers (20) and between second conductor track connections (28) of connected coil layers (20). [13] Print coil device according to one of the preceding claims, characterized bythat a distance between the coil layers (20) numbered i and i+1 is equal to a distance between corresponding coil layers (20) numbered n-i+1 and ni. [14] Print coil device according to one of the preceding claims, characterized by that the coil layers (20) with the numbering i=1 to i=n / 2 are spaced parallel and have an equal first distance (A1) from one another. [15] Print coil device according to one of the preceding claims, characterized by that the coil layers (20) with the numbering i=n / 2 to i=n are spaced parallel and have an equal second distance (A2) from one another. [16] Print coil device according to claim 15, characterized by that the second distance (A2) is equal to a first distance (A1) between coil layers (20) with the numbering i=1 to i=n / 2. [17] Print coil device according to one of the preceding claims, characterized bya first coil layer package (44) with coil layers numbered i=1 to i=n / 2 and a second coil layer package (46) with coil layers (20) numbered i=n / 2+1 to i=n, wherein no coil layer (20) of the first coil layer package (44) is directly electrically connected to another coil layer (20) of the first coil layer package (44) and no coil layer (20) of the second coil layer package (46) is directly electrically connected to another coil layer (20) of the second coil layer package (46). [18] Print coil device according to claim 17, characterized by that coil layers (20) of the first coil layer package (44) are directly electrically connected to coil layers (20) of the second coil layer package (46). [19] Print coil device according to claim 17 or 18, characterized bythat at least one further coil (16), in particular in the form of a printed coil, is arranged between the first coil layer package (44) and the second coil layer package (46), or a center tap is arranged. [20] Print coil device according to claim 19, characterized by that the at least one further coil (16) has a third terminal (62) and a fourth terminal (64). [21] Print coil device according to claim 19 or 20, characterized by that the at least one further coil (16) has a plurality of coil layers (78). [22] Print coil device according to one of claims 19 to 21, characterized by that the at least one further coil (16) is designed as a transmitting coil and the print coil (14) forms a receiving coil arrangement to which the at least one further coil (16) is arranged and / or connected in particular symmetrically. [23] Print coil device according to one of the preceding claims, characterized by a conductor guide for current transport through the at least one printed coil (14), which has a spiral shape when a conductor guide through the respective coil insert (20) is viewed in an equivalent circuit diagram as a straight conductor path between a first conductor track connection (26) of the respective coil layer (20) and a second conductor track connection (28) of the respective coil layer (20). [24] Print coil device according to claim 23, characterized by that a spiral axis (52) is oriented transversely to the axis (18) of the successive sequence of the coil layer (20). [25] Print coil device according to one of the preceding claims, characterized by that the at least one print coil (14) corresponds to an anti-serial arrangement of two individual coils. [26] Print coil device according to one of the preceding claims, characterized bythat the axis (18) of the successive sequence of coil layers (20) is oriented perpendicular to the coil layers (20) and in particular perpendicular to supports (22) of the coil layers (20). [27] Print coil device according to one of the preceding claims, characterized by that the axis (18) of the successive sequence of coil layers (20) is oriented parallel or coaxially to a coil axis (32) of the coil layers (20). [28] Print coil device according to one of the preceding claims, characterized by that the at least one print coil (14) is assigned a target (56) which has a movement component (58) coaxial or parallel and / or transverse to the axis (18) of the successive sequence of the coil layers (20). [29] Print coil device according to one of the preceding claims, characterized by a coil body (12) having an upper side (36) on which the first terminal (40) and the second terminal (42) are arranged. [30] Print coil device according to claim 29, characterized by that at least one further connection (62; 64) for at least one further coil (16) is arranged on the upper side (36). [31] Print coil device according to one of the preceding claims, characterized by a shielding device (60) for an electric field, which surrounds the coil layers (20) in a sleeve-like manner. [32] Print coil device according to claim 31, characterized by a plurality of spaced-apart current conducting paths (68) which are arranged at least approximately parallel to an axis (18) of a successive sequence of coil layers (20) and / or at least approximately parallel to coil axes (32) of the coil layers (20). [33] Print coil device according to claim 32, characterized by that current conducting paths (68) are located on an enveloping jacket (70) which surrounds the coil layers (20) in a sleeve-like manner. [34] Print coil device according to claim 32 or 33, characterized by that at least one current conducting path (68) is electrically connected to a terminal (40) of the at least one printed coil (14) and / or a further coil (16). [35] Print coil device according to one of claims 31 to 34, characterized by a current conducting network (72; 74) which is assigned to an upper side (36) and / or a lower side (38) of a coil body (12). [36] Print coil device according to one of the preceding claims, characterized by training as a gradiometer. [37] Use of the print coil device according to one of the preceding claims as a sensor element, in particular a proximity sensor or distance sensor. [38] Proximity sensor or distance sensor, in particular inductive proximity sensor or distance sensor, comprising at least one print coil device according to one of claims 1 to 36.

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