Coil arrangement for proximity sensor and method for producing such coil arrangement

Abstract

The invention relates to a coil arrangement (10) for a proximity sensor, comprising a flexible printed circuit board (12) on which a conductor track (14) is arranged, said conductor track having a first end region (20) and a second end region (22), the flexible printed circuit board (12) being rolled up about a roller axis (R) or folded about a folding axis (F), the conductor track (14) forms a coil (46); the invention relates to an electronic device (10) comprising a first end region (20), a second end region (22), a rigid circuit board (18) for connecting at least one electronic component (24), and electrical connection elements (16), the first end region (20) and the second end region (22) each being electrically connected to the rigid circuit board (18) by means of the electrical connection elements (16). As a result, a modular coil arrangement can be produced.

Description

Technical Field

[0001] The present invention relates to a coil device for proximity sensors and a method for producing such a coil device. Background Technology

[0002] Proximity sensors are known in practice to detect objects within a certain distance range. Inductive proximity sensors are based on the principle of detecting objects by measuring the changes caused by a metallic object in an oscillating electromagnetic field generated by a coil. Inductive proximity switches determine whether an object is within a certain distance of the sensor, while inductive distance sensors detect the distance and position of the object relative to the sensor.

[0003] Generally, proximity sensors operate on the principle that an excitation coil can be supplied with current to generate an oscillating electromagnetic field within the coil. If a metallic object is present near the proximity sensor, eddy currents will appear near the object's surface, induced by the changing magnetic field of the coil. This, in turn, causes a change in the electromagnetic field of the coil in terms of its geometry and strength. This change in the electromagnetic field can be detected by measuring the induced voltage in the excitation coil of the proximity sensor and / or in one or more individual detection coils.

[0004] Such coils in proximity sensors can be, for example, wire coils, coils structured on and / or in rigid circuit boards, or coils structured on and / or in flexible circuit boards. The latter, “flexible coils,” can be manufactured, for example, according to DE 10 2008 012120 B4. According to DE 10 2019 115 405 A1, different interconnections of several such “flexible coils” can be implemented on the circuit board of the “flexible coils.” These three manufacturing techniques require different manufacturing processes for each coil; therefore, depending on the coil type, the production of proximity sensors requires different manufacturing equipment and processes. To minimize the cost of manufacturing proximity sensors, it is best to standardize and homogenize the coil devices and their manufacturing, making them suitable for different types of proximity sensors or other product types using similar coils. Summary of the Invention

[0005] The present invention is based on the aim of providing, in particular, cost-effective coil devices, proximity sensors, and methods for generating coil devices.

[0006] This objective is achieved by the coil device, proximity sensor, and method of generating the coil device according to the independent claim. Advantageous embodiments are defined in the dependent claims.

[0007] According to a first aspect, a coil device for a proximity sensor is provided, the coil device comprising: a flexible circuit board on which a conductor track is arranged, the conductor track having a first end region and a second (particularly another) end region, wherein the flexible circuit board is rolled up about a roller axis or folded about a folding axis such that the conductor track forms a coil; a rigid circuit board for electrically connecting at least one electronic component; and an electrical connection element wherein the first end region and the second end region are each electrically connected to the rigid circuit board by means of the electrical connection element.

[0008] This results in a modular coil device that can be used, for example, as an excitation and / or detection element for any type of sensor (particularly a proximity sensor, a gradiometer sensor, or a gradient sensor). The modular coil device has three standardizable components: a coil based on a flexible circuit board, a rigid circuit board on which electronic components for a proximity sensor can be placed, and an electrical connection element for electrical and mechanical connection between the two circuit boards.

[0009] Because of the rolled-up or folded circuit board, the size (e.g., diameter) of the coil can be scaled particularly easily, allowing the use of sensor housings of different sizes, such as M18, M12, M8, etc. Several basic coil types can also be implemented using flexible circuit boards. Since flexible circuit boards are oriented differently than coils based on rigid circuit boards, new coil types with a wide range of electrical properties can be realized.

[0010] Rigid circuit boards can be used as configuration modules for corresponding sensor types because the corresponding electrical connections from the coil to the rigid circuit board enable different applications of the coil device. These connecting elements can also be standardized, depending on the number and type available. In this context, the term "standardization" can be understood to mean that production or capacity can be standardized. Specifically, this term does not imply that DIN standards or standard specifications must be met.

[0011] In summary, the modular design reduces or minimizes necessary manufacturing steps, logistics in the manufacturing process, and the types of manufacturing tools used. Furthermore, a complete product portfolio can be achieved with several variations of the three components, thereby reducing the complexity of manufacturing different proximity sensors. Additionally, the development of further products based on this modular coil device can be accelerated, as redesigning components may require less planning time. For example, it may only be necessary to redesign the rigid circuit board, as the coil and connecting elements can be reused.

[0012] In summary, the coil device according to the invention thus enables the production of coil devices and coil devices, as well as proximity sensors, to be particularly cost-optimized and / or cost-effective.

[0013] The flexible conductor track can be rolled up or folded at least once, and especially several times, along its entire circumference or completely (particularly in an overlapping manner). The coil formed by the conductor track can have the same number of turns as the circuit board being rolled up or folded around the folding axis. Here, the roller axis or folding axis can extend perpendicularly to the plane of the coil, that is, perpendicularly to the plane in which the coil can substantially extend.

[0014] In one embodiment, the connecting element has solder or solder paste. This allows for a direct connection between two circuit boards.

[0015] In one embodiment, the connecting element has at least one flexible printed circuit (FPC) connector, allowing for a wide range of connectors with varying sizes and mountability. For example, a surface-mountable FPC connector can be directly soldered onto a rigid circuit board along with other electronic surface mount devices (SMDs) or components of the proximity sensor. Furthermore, soldering between the flexible and rigid circuit boards can be eliminated. Mechanical and electrical connections are achieved by assembling the relevant components in a rapidly achievable manufacturing process. Here, the end regions of the flexible circuit board, and therefore the end regions of the conductor tracks, can be inserted into corresponding slots in the FPC connector and held in place by a locking mechanism or another mechanical fixing mechanism, preventing the end regions from slipping out of the connector. Although the FPC connector as an additional component may increase manufacturing costs, a coil assembly manufactured in this way may be more cost-effective than a coil assembly where two circuit boards can be soldered together.

[0016] In one embodiment, the roller axis or folding axis of the flexible circuit board extends substantially parallel to or parallel to the extension of the rigid circuit board. In this embodiment, the coil plane or the body of the flexible circuit board can therefore extend laterally, and particularly perpendicularly, to the extension of the rigid circuit board. Here, the end regions of the flexible circuit board (where the conductor tracks are arranged) can be bent or folded in such a way that the end regions of the conductor tracks are arranged parallel to the rigid circuit board, for example, to simplify the soldering of the two circuit boards. This measure ensures that the length of the rigid circuit board is not affected by the diameter of the coil. The electronic components of the proximity sensor can be accommodated particularly easily on the resulting enlarged surface of the rigid circuit board.

[0017] In one embodiment, the roller axis or folding axis of the flexible circuit board extends substantially transversely to, and particularly perpendicularly to, the extension of the rigid circuit board. In this configuration, the end regions of the conductor tracks and the end regions of the flexible circuit board can be bent so that they extend parallel to the extension of the rigid circuit board. In this configuration of coil arrangement, the available surface area on the rigid circuit board for placing the electronic components for the proximity sensor may be limited. However, the coil arrangement can be implemented very compactly and can be easily integrated into a housing.

[0018] In one embodiment, contact points for the first end region of the conductor track are arranged on one side of the rigid circuit board, and contact points for the second end region of the conductor track are arranged on a second (particularly another) side of the rigid circuit board. This embodiment makes it particularly easy to arrange the rigid circuit board parallel to the roller axis or folding axis. In other words, the rigid circuit board can be connected to different end regions of the conductor track on two different sides.

[0019] In one embodiment, contact points for the first and second end regions of the conductor track, or contact points for connecting elements, are arranged on one side of the rigid circuit board, while contact points for at least one component are arranged on a second (particularly another) side of the rigid circuit board. In other words, the rigid circuit board can be connected to the conductor track only on one side, while the component can be arranged on the other side. In this relative arrangement of the two circuit boards, they can be connected particularly easily. This embodiment can be used particularly easily with cases where the rigid circuit board is arranged transversely to, and particularly perpendicularly to, the roller axis or folding axis.

[0020] In one embodiment, at least one second conductor track (i.e., additional conductor tracks) is arranged on the flexible circuit board, the at least one second conductor track having a first end region and a second end region, wherein the conductor track and at least the second conductor track extend substantially adjacent to each other (particularly on the same side of the flexible circuit board), wherein the at least second conductor track forms at least a second coil. Specifically, the conductor tracks may extend substantially parallel to each other (e.g., until the end regions). This allows the number of coils in the coil arrangement to be scalable to improve the excitation of the electric field and / or the detection of the induced voltage. In particular, given the same size coil arrangement, more coils can be accommodated in the coil arrangement compared to wire coils or rigid circuit boards with coils. Using a flexible circuit board with multiple conductor tracks also makes it easier to achieve axially offset and precisely positioned coils compared to the other two coil types.

[0021] Rigid circuit boards can have corresponding contact points as described above. Because more rigid circuit boards are used to interconnect different coils, the electrical interconnection of multiple coils in the manufacturing process can be standardized and thus simplified.

[0022] In one embodiment, the first and second end regions of the conductor track, and at least the first and second end regions of the second conductor track, are electrically connected to the rigid circuit board in such a way that the first coil and at least the second coil are electrically isolated coils. Depending on the desired application, this allows electrically independent coils to be constructed in such a way that corresponding contacts are made on the rigid circuit board. If desired, exactly the same number of electrically independent coils as those on the flexible circuit board can be generated.

[0023] In one embodiment, the first and second end regions of the conductor rails, and at least the first and second end regions of the second conductor rails, are electrically connected to a rigid circuit board in such a way that the first and second coils are a common coil. For this purpose, the end region of the first coil (e.g., on a first side of the rigid circuit board) may be electrically connected to the end region of the second coil (e.g., on a second or other side of the rigid circuit board), or the end region of the second coil (e.g., on a first side of the rigid circuit board) may be electrically connected to the end region of the first coil (e.g., on a second or other side of the rigid circuit board). This creates an assembled coil with three terminals. The resulting coil arrangement can be used in a Hartley oscillator.

[0024] In one embodiment, the first and second end regions of the conductor rails, and at least the first and second end regions of the second conductor rails, are electrically connected to a rigid circuit board in such a way that the first and second coils are connected in series. This allows for the formation of an assembled coil with more turns and capable of generating a correspondingly stronger electromagnetic field. Furthermore, the induced voltage can be increased.

[0025] The three embodiments described above allow for easy and flexible modification of the number, design, and function of the resulting coils, as only the contact between the first and second coils on the rigid circuit board needs adjustment. In other words, based on the same coils formed from a flexible circuit board with conductor tracks, a wide variety of coil devices can be easily created by changing the configuration of the rigid circuit board with its contact points. This avoids the direct contact between the first and second coils on the flexible circuit board, which is technically more difficult due to the alignment of the first and second coils. Furthermore, electronic components can be placed directly on the rigid circuit board and do not need to be in contact with the flexible circuit board either.

[0026] In one embodiment, the coil arrangement further includes a core element, which may be made of or formed of a ferromagnetic material, particularly ferrite, wherein the core element may be arranged inside the coil in the coil plane. In this context, the ferrite may belong to the ferrite class and may be a soft or hard magnetic material, typically a ceramic material. In particular, the selected ferrite material may be hard magnetic. Specifically, iron may not be used as the material for the core element. The core element may fill the interior of the coil, which may be defined by conductor tracks or a flexible circuit board, and the outer surface of the core element (which may extend transversely (particularly perpendicularly to) the coil plane) may be adapted to the internal shape of the rolled-up or folded flexible circuit board. The core element may also be constructed as a plate, arranged parallel to the coil plane, and filling the interior of the coil.

[0027] The coil assembly may further include a sheath that laterally surrounds the rolled-up or folded flexible circuit board and thus the coil on its outer side and in the covered area. The sheath may also comprise or be made of a ferromagnetic material, which may be the same as or different from the ferromagnetic material of the core element. In particular, the ferromagnetic material may comprise (e.g., hard magnetic) ferrite. Iron may not be used as the material of the sheath. The sheath may have side elements that surround and / or cover the outer side of the flexible circuit board. Furthermore, the sheath may have a cover element that covers one side of the coil. The sheath may also have another cover element that covers the other side of the coil. The height of the core element may be dimensional such that the cover element and the core element are flush with each other. The core element and the sheath may be constructed as a single piece.

[0028] These two measures allow the electromagnetic field of the coil to be oriented towards the object being detected and increase the field strength of the coil's electromagnetic field. This increases the detection range of the proximity sensor and allows it to detect objects at greater distances. This is particularly advantageous for inductive proximity switches.

[0029] In one embodiment, the flexible circuit board has two lugs extending parallel to the roller axis or folding axis, wherein the end regions of the conductor tracks are each arranged on a different lug of the two lugs (particularly on the outer side away from the coil or axis or the inside of the coil). In other words, a first end region may be arranged on a first lug, and a second end region may be arranged on a second lug. When viewed from above the coil plane, the lugs may be arranged in opposite regions of the coil. This allows contact of the coil to be provided at a distance from the coil plane, thereby minimizing electrical interference to the field generated by the coil. In particular, the core element may in each case have a (particularly semi-circular) recess in the lug region that opens or widens outward (i.e., away from the inside of the coil) and may extend through one of the two lugs in each case. If only one covering element is present in the sheath, the covering element may be arranged on the same side of the coil and the lug.

[0030] In one embodiment, the cross-section of the rolled or folded flexible circuit board, which extends laterally, and particularly perpendicularly, to the roller axis or fold axis, is circular, elliptical, rectangular, or square. This allows the corresponding coil shape to be advantageously adapted to the design of the proximity sensor.

[0031] In one embodiment, conductor tracks extend on a flexible circuit board in a straight, wavy, or zigzag pattern. This allows for adjustment of the inductance, resistance, and / or coupling coefficient of the shaped coil to specifically optimize the coil's electrical properties for the desired application.

[0032] In one embodiment, the flexible circuit board is configured as multilayered, wherein conductor tracks are arranged in a first layer of the flexible circuit board, wherein at least a second conductor track is arranged in at least a second layer of the flexible circuit board, wherein the at least second conductor track forms at least a second coil, and wherein the end regions of the first and second conductor tracks are arranged on the (particularly common) outer surface of the flexible circuit board via plated through-holes. This can increase the number or density of conductor tracks and thereby improve the overall performance of the coil to be formed. The endpoints of the conductor tracks may be arranged on a conductive outer layer of the circuit board, which may or may not have conductor tracks.

[0033] In one embodiment, the conductor rails are configured to have at least two strands, particularly multiple strands, in their central region. In other words, each strand of the conductor rail may each have a common first and second end. This allows the conductor rails to form stranded wires. Although this increases manufacturing costs, it can be advantageous for certain sensor applications. Specifically, the strands can be implemented on a circuit board in such a way that they spread out at acute angles from (particularly straight) end regions and then extend adjacent to each other (particularly parallel to each other) in the central region of the circuit board.

[0034] It should be understood that at least the second coil can be implemented in the same manner as described above (e.g., regarding its cross-section, its length, and / or the number of its strands).

[0035] Flexible circuit boards may, for example, contain or be composed of polyimide. This material provides the necessary structural integrity for the coils.

[0036] The coils that are rolled up or folded can be held in place in the appropriate shape, for example by means of adhesives or mechanical fixation.

[0037] According to the second aspect, a proximity sensor is provided, the proximity sensor having a coil arrangement according to the first aspect, wherein the proximity sensor is an inductive proximity switch or an inductive distance sensor.

[0038] According to a third aspect, a method for generating a coil device for a proximity sensor is provided, the method comprising the steps of: providing a flexible circuit board on which conductor tracks are arranged, the conductor tracks having a first end region and a second end region, wherein the flexible circuit board is rolled up about a roller axis or folded about a folding axis such that the conductor tracks form a coil; providing a rigid circuit board for electrically connecting at least one electronic component; providing an electrical connection element, and by means of the electrical connection element electrically connecting each of the first end region and the second end region to the rigid circuit board.

[0039] The flexible circuit board can be rolled up or folded, for example, using a plastic coil frame or without such a frame. The flexible circuit board can be fixed by mechanical means or adhesive as described above.

[0040] If solder paste is used as a connecting element, it can be applied to one or two circuit boards. The two circuit boards can then be positioned relative to each other. Applying heat allows the solder paste to melt, thus establishing electrical and mechanical contacts between the two circuit boards. To connect two circuit boards in this way, the solder paste must be applied immediately before joining to avoid contaminating the solder paste.

[0041] If solder paste is used as a connecting element in reflow soldering, it can be applied before the flexible circuit board is attached to the rigid circuit board. In this process, solder paste is applied to the rigid circuit board, heated, and then cooled. Afterward, as a separate manufacturing step, flux is added to the already "soldered" surface to aid reflow. After adding flux, the flexible circuit board is positioned on the rigid circuit board. When heated, the solder paste melts. After cooling, the two circuit boards are joined in the same way as if only solder paste were used.

[0042] Solder can also be used as a connecting element to solder the two circuit boards. Therefore, in this variant, solid solder can be used, which allows for easy connection of the two circuit boards. Attached Figure Description

[0043] Exemplary embodiments of the present invention are illustrated in the accompanying drawings and explained in more detail in the following description. In the drawings:

[0044] Figure 1 A schematic diagram of a coil device for a proximity sensor according to a first exemplary embodiment is shown;

[0045] Figure 2A , Figure 2B It shows Figure 1 An example of a flexible circuit board for a coil device;

[0046] Figure 3A , Figure 3B It shows Figure 1 Another example of a flexible circuit board;

[0047] Figure 4A , Figure 4B It shows Figure 1 Another example of a flexible circuit board;

[0048] Figure 5 Shown in plan view Figure 1 Another example of a flexible circuit board;

[0049] Figure 6 Shown in plan view Figure 1 Another example of a flexible circuit board;

[0050] Figure 7 It shows Figure 1 A perspective view of another example of a flexible circuit board;

[0051] Figure 8 It shows Figure 7 A flexible circuit board having a core element and a sheath;

[0052] Figure 9A , Figure 9B Shown in plan view Figure 1 The first and second sides of an example of a rigid circuit board;

[0053] Figure 10A , Figure 10B Shown in plan view Figure 1 Another example of a rigid circuit board is the first and second sides;

[0054] Figure 11A , Figure 11B Shown in cross-sectional view and enlarged cross-sectional view Figure 1 An example of a coil device;

[0055] Figure 12 Shown in plan view Figure 1 The first side of another example of a rigid circuit board;

[0056] Figure 13A , Figure 13B Shown in cross-sectional view and enlarged cross-sectional view Figure 1 An example of a coil device;

[0057] Figure 14 An embodiment of the invention for manufacturing is shown. Figure 1 The method of the coil device in the middle; and

[0058] Figure 15 It shows the use of in Figure 14 A block diagram of the components used in the method. Detailed Implementation

[0059] Identical or similar parts or components are provided with the same component symbol.

[0060] exist Figure 1The coil device according to an exemplary embodiment, indicated by element symbol 10 and adapted for proximity sensor 11, has a flexible circuit board 12 that is fully rolled up several times to overlap around a roller axis R, or fully folded several times to overlap around a folding axis F, and a conductor track 14 is arranged on the flexible circuit board. The conductor track 14 forms a coil. The circuit board 12 is electrically connected to a rigid circuit board 18 by means of an electrical connection element 16, such that a first end region 20 and a second end region 22 of the conductor track 14 are coupled to the rigid circuit board 18 by means of the connection element 16. Several electronic components 24 are arranged and contact the rigid circuit board 18, for example, to enable power supply to the conductor track 14 and / or to evaluate the voltage induced in the conductor track 14. For clarity, only one component is indicated by element symbol 24.

[0061] The connecting element 16 is configured as an FPC connector. For this purpose, the end regions 20, 22, which are bent from the coil plane, are inserted into the corresponding slots of the FPC connector 16. The coil plane extends perpendicular to the axes R, F. The FPC connector 16 is inserted into the rigid circuit board 18 via pins.

[0062] Figure 2A , Figure 2B The unrolled or folded circuit board 12 shown has an elongated central region 28 (partially shown), the two end regions of which are each configured as lugs 30a and 30b and extend substantially perpendicular to the central region 28. The diameters of the lugs 30a and 30b widen towards their ends relative to the central region 28. Three conductor tracks 14a to 14c extend from their respective first end regions 20a to 20c along the lugs 30a and the central region 28 on the common outer side A of the circuit board 12 to their second end regions 22a to 22c on the lugs 30b. The ends of the end regions 20a to 20c and 22a to 22c are configured as contact points having a surface area that increases relative to the diameter of the conductor tracks 12.

[0063] Figure 2A , Figure 2B The circuit board 12 can also be constructed as a multilayer structure. Only conductor track 14a is structured in the first outer layer. Conductor track 14b is formed in a second conductive layer, which is disposed inside the circuit board 12, below the outer layer, and electrically insulated from the outer layer. Conductor track 14c is formed in a third conductive layer, which is disposed inside the second layer, below the second layer, and electrically insulated from the second layer. Conductor tracks 14b and 14c are connected to conductor track 14a via corresponding plated through-holes.

[0064] Figure 3A , Figure 3BTwo examples of circuit board 12 shown in the figure and Figure 2A , Figure 2B The circuit board 12 is similarly constructed, differing only in that the conductor tracks 14a to 14c in the intermediate region 28 do not run in a straight line, but rather in a wavy shape. Figure 3B ) or Z-shaped ( Figure 3B (Delayed)

[0065] In Figure 2A , Figure 2B The circuit board 12 in the middle is constructed similarly. Figure 4A , Figure 4B In the example of circuit board 12 shown, each conductor track 14a to 14c has one strand in its end regions 20a, 20b, 20c, 22a, 22b, 22c. Figure 2A , Figure 2B In contrast, conductor tracks 14a to 14c are arranged in three strands in the regions of lugs 30a and 30b toward the central region 30, such that nine conductor track strands 34a to 34c, 36a to 36c, and 38a to 38c extend in the central region 28 of circuit board 12. The branches are configured such that conductor track strands 34a to 34c, 36a to 36c, and 38a to 38c separate from their respective adjacent conductor track strands 34a to 34c, 36a to 36c, and 38a to 38c at acute angles.

[0066] Alternatively, a nine-strand coil can be formed as follows: Figure 4A , Figure 4B The circuit board is constructed as a multi-layered structure. End regions 20a to 20c, 22a to 22c, and strands 34a, 36a, and 38a are structured in the first outer layer. Strands 34b, 36b, and 38b are formed in a second conductive layer, which is disposed inside the circuit board 12, below the outer layer, and electrically insulated from the outer layer. Each strand extends in the intermediate region 28. Figure 4A , Figure 4B The diverging points in the middle. Shares 34c, 36c, and 38c are formed in a third conductive layer, which is disposed inside the second layer and below it, and is electrically insulated from the second layer. Each share extends in the intermediate region 28 to... Figure 4A , 4B The diverging points in the middle. Strands 34b, 36b, 38b and 34c, 36c, 38c are connected to strands 34a, 36a, 38a via corresponding plated through holes.

[0067] like Figure 5 and Figure 6 As shown, the cross-section of the rolled-up or folded circuit board 12, which extends perpendicularly to the roller axis R or the folding axis F, can be constructed as a circle. Figure 5 ) or square ( Figure 6 Alternatively, the cross-section may be elliptical or rectangular. The flexible circuit board 12 may be held in its rolled-up or folded position mechanically or by means of adhesive 42 using clamps 40. Mechanical clamps are provided at the end regions 44a, 44b of the circuit board 12. Conductor tracks 14 extend along the outer side A of the rolled-up flexible circuit board 12. Adhesive 42 is applied to the inner side B of the flexible circuit board 12 such that the conductor tracks 14 are located below the adhesive 42 in the overlapping area of ​​the circuit board 12. The rolled-up or folded circuit board forms a coil 46. The circuit board 12 or conductor tracks 14 may be rolled up or unrolled into multiple turns, such that the coil 46 formed by the conductor tracks 14 has multiple turns.

[0068] Figure 7 A perspective view of the rolled-up circuit board 12 together with lugs 30a and 30b is shown. Conductor tracks (not shown) extend along the outer side A of the circuit board 12.

[0069] exist Figure 8 In this coil, a plate-shaped circular core element 52, made of a hard magnetic material (especially ferrite), is arranged inside the coil 46 in the coil plane. Furthermore, a sheath 54, also made of the same ferromagnetic material, encloses the core. Figure 7 The coil 46 is formed. The sheath 54 has a side element 55a that covers the outer side A of the flexible circuit board 12. Additionally, the sheath 54 has an annular cover element 55b that covers one side of the coil 46. The height of the core element 52 is dimensionally set such that the cover element 55b and the core element are flush with each other. The core element 52 and the sheath 54 are constructed as a single piece. In the region of the bending point of the lugs 30a, 30b, the core element 52 has recesses 56a, 56b in each case, through which different lugs of the lugs 30a, 30b extend vertically away from the coil plane. The cover element 55b is arranged on the same side of the coil 46 as the lugs 30a, 30b.

[0070] Figure 9A , Figure 9BAn example of a rigid circuit board 18 is shown, with its first side C and second side D connected to a flexible circuit board 12 (not shown). The flexible circuit board has five parallel conductor tracks 14a to 14e. The end regions 20a to 20e and 22a to 22e of the conductor tracks 14a to 14e are soldered to corresponding contact points 60a to 60e and 62a to 62e on the circuit board 18, respectively, by means of connecting elements 16 in the form of solder paste. The contact points 60a to 60e and 62a to 62e are then connected by plated through-holes 64a to 64d and 66a to 66d provided on the rigid circuit board 18, such that five coils formed by the five conductor tracks 14a to 14e on the flexible circuit board 12 are connected in series, forming a single assembled coil. The coil ends 66a and 66b arranged on each side C and D of the circuit board 18 can be used for contact members 24.

[0071] Figure 10A , Figure 10B The example of rigid circuit board 18 shown in the figure is similar to Figure 9A , Figure 9B The example in the diagram is constructed similarly. However, only three plated through-holes 64a to 64c exist, which (viewed from the left) connect the first conductor track 14a to the second conductor track 14b and the third conductor track 14c, respectively, and connect the fourth conductor track 14d to the fifth conductor track 14e. Thus, two assembled coils are formed by means of the contact of the rigid circuit board 18, each of the two assembled coils being electrically isolated from the other. The corresponding coil ends 66a, 66b and 68a, 68b of the first and second coils are structured on the rigid circuit board.

[0072] Alternatively, the end 66b of the first coil on side D can be connected to the end 68a of the second coil on the second side C of the rigid circuit board 18, or the end 68b of the second coil on the first side D can be connected to the end 66a of the first coil on the second side C. This circuit will create a common coil with three terminals, which can be used, for example, in a Hartley oscillator.

[0073] exist Figure 11A , Figure 11BIn the exemplary embodiment of the coil device 10 shown, the rigid circuit board 18 is arranged perpendicular to the coil plane intersecting the rolled-up or folded flexible circuit board 12 and along axes R and F. The longitudinal extension of the rigid circuit board 18 is therefore parallel to or extends in the direction of the axes R and F of the circuit board 12. Lugs 30a and 30b are bent at acute angles from the coil plane, and the end regions of the lugs 30a and 30b are bent toward and parallel to the rigid circuit board 18. To connect the circuit board 12 to the rigid circuit board 18, solder 16a and 16b are provided as connecting elements, which are disposed between copper contacts 60 and 62 on each side C and D of the rigid circuit board 18 and ends 20 and 22 on the flexible circuit board 12.

[0074] exist Figure 12 In the example of the rigid circuit board 18 shown, contacts 60a to 60e and 62a to 62e are arranged on one side C, and the end regions 20a to 20e and 22a to 22e of conductor tracks 14a to 14e are coupled to this side. The conductor tracks 14a to 14e thus form coils connected in series. Contacts 60b, 62a and 60c, 62b, and 60d, 62c and 60e, 62d are connected to each other by means of conductor strands 70a to 70d structured on the rigid circuit board 18. Plated through-holes 64a and 64b connect the assembled coils to electronic components 24 arranged on the other side of the rigid circuit board 18.

[0075] exist Figure 13A , Figure 13B In the exemplary embodiment of the coil device 10 shown, the flexible circuit board 12 and the rigid circuit board 18 are arranged parallel to each other. In other words, axes R and F extend perpendicularly to the rigid circuit board 18. Lugs 30a and 30b are folded such that they bend twice at right angles relative to the circuit board 12 and then extend parallel to the flexible circuit board 12. Connecting elements 16a and 16b in the form of solder are soldered between corresponding contact points 60a and 60b on the rigid circuit board 18 and the end regions 20 and 22 of the conductor track 14. In this case, the end regions 20 and 22 are configured as solder contact points.

[0076] exist Figure 14In the method shown for generating a coil device 10 for a proximity sensor 11, in a first step S1, a flexible circuit board 12 is provided, on which a conductor track 14 is disposed. The circuit board 12 is completely rolled up once or several times around a roller axis R, or completely folded once or several times around a folding axis F, such that the circuit board 12 and the conductor track 14 together form a coil 46. In a second step S2, a rigid circuit board 18 is provided. In a further method step S3, an electrical connection element 16 is provided. In a subsequent method step S4, the flexible circuit board 12 is connected to the rigid circuit board 18, such that the first end region 20 and the second end region 22 of the conductor track 14 are electrically connected to the rigid circuit board 18 by means of the connection element 16.

[0077] Steps S1 to S3 can be performed in any order.

[0078] Figure 15 The coil assembly 10 is illustrated by its modular formation from three components: a coil component 90, a connecting element component 92, and a configuration circuit board component 94. The coil component 90 can represent a different type of circuit board 12 having conductor tracks 14, such as… Figures 2A to 8 As described. Three coil components 90a to 90c are shown as examples. Connecting elements in the form of solder or solder paste (component symbol 92a) or connecting elements 16 in the form of FPC connectors (component symbol 92b) can be selected as connecting element components 92a, 92b. Then, the desired rigid circuit board 18 can be selected as configuration circuit board components 94a to 94e, such as, for example Figures 9A to 13B As described. In this way, the proximity sensor 11 can be constructed in a particularly simple modular manner.

Claims

1. A coil device (10) for a proximity sensor (11), comprising: - A flexible circuit board (12) on which a conductor track (14) is arranged, the conductor track having a first end region (20) and a second end region (22), wherein the flexible circuit board (12) is rolled up about a roller axis (R) or folded about a folding axis (F) such that the conductor track (14) forms a coil (46). - Rigid circuit board (18), said rigid circuit board for connecting at least one electronic component (24), and - Electrical connection element (16). The first end region (20) and the second end region (22) are each electrically connected to the rigid circuit board (18) by means of the electrical connection element (16).

2. The coil device (10) according to claim 1, wherein the connecting elements (16a, 16b) have solder or solder paste.

3. The coil device (10) according to claim 1, wherein the connecting element (16) has at least one FPC connector.

4. The coil device (10) according to any one of the preceding claims, wherein the roller axis (R) or folding axis (F) of the flexible circuit board (12) extends substantially parallel to the extension of the rigid circuit board (18).

5. The coil device (10) according to any one of claims 1 to 4, wherein the roller axis (R) or folding axis (F) of the flexible circuit board (12) extends substantially transversely to, and in particular perpendicularly to, the extension of the rigid circuit board (16).

6. The coil device (10) according to any one of claims 1 to 5, wherein the contact points (60a to 60e) for the first end region (20) of the conductor track (14) are arranged on one side (C) of the rigid circuit board (18), and the contact points (62a to 62e) for the second end region (22) of the conductor track (14) are arranged on the second side (D) of the rigid circuit board (18).

7. The coil device (10) according to any one of claims 1 to 5, wherein the contact points (60a to 60e, 62a to 62b) of the first end region (20) and the second end region (22) of the conductor track (14) are arranged on one side (C) of the rigid circuit board (18), wherein the contact points for the at least one electronic component (24) are arranged on the second side of the rigid circuit board (18).

8. The coil device (10) according to any one of the preceding claims, wherein at least one second conductor track (14a to 14e) is arranged on the flexible circuit board (12), the at least one second conductor track having a first end region (20a to 20e) and a second end region (22a to 22e), wherein the conductor track (14a to 14e) and the at least second conductor track (14a to 14e) extend substantially adjacent to each other, particularly parallel to each other, wherein the at least second conductor track (14a to 14e) forms at least a second coil (46).

9. The coil device (10) according to any one of the preceding claims, wherein the first end region (20a to 20e) and the second end region (22a to 22e) of the conductor rails (14a to 14e) and the first end region (20a to 20e) and the second end region (22a to 22e) of the at least second conductor rails (14a to 14e) are electrically connected to the rigid circuit board (18), such that the first coil (46) and the at least second coil (46) are electrically isolated coils (46).

10. The coil device (10) according to any one of claims 1 to 8, wherein the first end region (20a to 20e) and the second end region (22a to 22e) of the conductor rails (14a to 14e) and the first end region (20a to 20e) and the second end region (22a to 22e) of the at least second conductor rails (14a to 14e) are electrically connected to the rigid circuit board (18) such that the first coil (46) and the second coil (46) are a common coil (46).

11. The coil device (10) according to any one of claims 1 to 8, wherein the first end region (20a to 20e) and the second end region (22a to 22e) of the conductor rails (14a to 14e) and the first end region (20a to 20e) and the second end region (22a to 22e) of the at least second conductor rails (14a to 14e) are electrically connected to the rigid circuit board (18) such that the first coil (46) and the second coil (46) are connected in series.

12. The coil device (10) according to any one of the preceding claims, wherein the coil device (10) further comprises a core element (52) having a ferromagnetic material, particularly ferrite, wherein the core element (52) is arranged in the coil plane inside the coil (46).

13. The coil device (10) according to any one of the preceding claims, wherein the flexible circuit board (12) has two lugs (30a, 30b) extending parallel to the roller axis (R) or the folding axis (F), wherein the end regions (20, 22) of the conductor track (14) are arranged on each of the two lugs (30a, 30b).

14. The coil device (10) according to any one of the preceding claims, wherein the cross section of the rolled or folded flexible circuit board (12) extending transversely to, and in particular perpendicularly to, the roller axis (R) or the folding axis (F) is circular, elliptical, rectangular or square.

15. The coil device (10) according to any one of the preceding claims, wherein the conductor track (14) extends on the flexible circuit board (12) in a straight, wavy or Z-shaped pattern.

16. The coil device (10) according to any one of the preceding claims, wherein the flexible circuit board (12) is configured as multilayered, wherein the conductor track (14) is arranged in a first layer of the flexible circuit board, wherein the second conductor track is arranged in at least a second layer of the flexible circuit board, wherein the end regions of the first conductor track and the second conductor track are arranged on the outer surface of the flexible circuit board (12) by means of plated through-holes.

17. The coil device (10) according to any one of the preceding claims, wherein the conductor track (14) is configured to be in at least two strands in its intermediate region.

18. A proximity sensor (11) having a coil device (10) according to any one of claims 1 to 17, wherein the proximity sensor (11) is a proximity switch or a distance sensor.

19. A method for producing a coil device (10) for a proximity sensor (11), the method comprising the steps of: - Provide (S1) a flexible circuit board (12) on which a conductor track (14) is arranged, the conductor track having a first end region (20) and a second end region (22), wherein the flexible circuit board (12) is rolled up about a roller axis (R) or folded about a folding axis (F) such that the conductor track (14) forms a coil (46). - Provide (S3) a rigid circuit board (18) for electrically connecting at least one electronic component (24); - Provide (S2) electrical connection element (16); and - Each of the first end region (20) and the second end region (22) is electrically connected (S4) to the rigid circuit board (18) by means of the electrical connection element (16).

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