Coil circuit board and method for manufacturing a coil circuit board

Abstract

A coil circuit board, in particular for an inductive proximity switch, in particular designed for flush mounting into a metallic environment, comprising: an insulating carrier material; at least one coil element constructed on or in the insulating carrier material; and a surrounding and closed recess constructed in the insulating material, which surrounds the coil element; and a separate preformed shielding element which is arranged exactly fitting in the recess. A method for producing a coil circuit board, comprising the following steps: providing a coil circuit board comprising an insulating carrier material and at least one coil element constructed on or in the insulating carrier material; producing a surrounding and closed recess in the insulating carrier material, wherein the recess surrounds the coil element; and inserting a separate preformed shielding element into the recess.

Description

Technical Field

[0001] This disclosure relates to a coil circuit board, particularly a coil circuit board for inductive proximity switches, which is especially suitable for flush mounting in a metallic environment. Furthermore, this disclosure relates to a method for manufacturing the disclosed device, particularly a method for manufacturing an inductive proximity switch. Additionally, this disclosure relates to the use of the disclosed device in an inductive proximity switch. Background Technology

[0002] Inductive proximity sensors are used in a variety of industrial applications to detect the presence or movement of metallic objects. These sensors typically operate by generating and evaluating an electromagnetic field produced by coils on a printed circuit board.

[0003] Two main implementation schemes for this type of sensor are known: flush-mountable proximity sensors and non-flush-mountable proximity sensors. In non-flush-mountable sensors, a gap must be maintained between the coil and the metallic environment to avoid interference with sensor function. In flush-mountable sensors, the coil is positioned directly on the front side of the sensor housing, allowing integration of the sensor into a metallic environment without the need for a gap. This is particularly important when the sensor should be integrated into a metallic environment (e.g., within machine parts or base plates).

[0004] To shield electromagnetic coils from external interference from metallic environments, shielding devices are typically used. In existing technologies, shielding elements are either mounted directly around the coil or secured using additional materials such as potting compound. However, these solutions are insufficient for the precise positioning and fixation of the shielding device.

[0005] DE 10 2021 114 948 A1 illustrates a proximity sensor for inductively detecting objects. The sensor includes a housing with a front cap forming the detection side of the sensor. A processing and receiving unit, including a printed circuit board, can be connected to an external control and / or evaluation unit. At least one primary coil and at least one secondary coil are arranged spaced apart along the axial direction on a single-piece or multi-piece coil holder, wherein the coils are either wound or printed. The end face of the coil holder directly faces or abuts the inner surface of the front cap. Here, the secondary coil is arranged closer to the end face along the axial direction than the primary coil. A metal shielding element is arranged in and around the axial region of the secondary coil, while no metal shielding element is provided in the axial region of the primary coil.

[0006] The main drawback of existing technologies is that the coil shielding devices in inductive proximity sensors are often poorly positioned and require additional processing steps (such as potting or bonding the shielding elements). This approach complicates the manufacturing process, increases production costs, and results in inaccurate shielding. Furthermore, incorrect positioning of the shielding elements can affect the sensor's effective distance and sensitivity. Summary of the Invention

[0007] In the context of the prior art, the purpose of this disclosure is to provide an apparatus for a shielded coil circuit board, a method for manufacturing the apparatus, and the use of the apparatus in an inductive proximity switch, which are accordingly adapted to at least partially overcome the aforementioned disadvantages of the prior art and enrich the prior art.

[0008] The purpose of this technology is particularly to provide equipment that ensures the precise positioning and fixation of shielding elements while simplifying and optimizing the manufacturing process. In particular, the equipment should be able to optimize sensor sensitivity and effective range through improved shielding, while reducing production costs.

[0009] Accordingly, this objective is achieved by a coil circuit board, particularly for inductive proximity switches, especially those designed for flush mounting in metallic environments. The coil circuit board includes an insulating carrier material and at least one coil element constructed on or within the insulating carrier material. Furthermore, the coil circuit board has a surrounding and closed groove constructed within the insulating carrier material, encircling the coil element. It is also proposed that separate, pre-formed shielding elements are precisely matched and arranged within the groove of the coil circuit board.

[0010] The technical advantage of this feature is that it effectively shields the coil, protecting it from electromagnetic interference. This results in improved sensitivity and stability of the sensor because the shielding device is precisely and stably positioned in the groove, thereby enhancing sensor performance.

[0011] In the sense of this disclosure, an inductive proximity switch can be understood as a non-contact sensor based on the generation and detection of electromagnetic fields. This switch detects the approach of a metallic object and triggers its switching function without direct contact. At least one transmitting coil and / or receiving coil is provided, responsible for generating or detecting the electromagnetic field. The technical advantage of this switch is that it enables reliable detection in industrial applications where mechanical operation is inapplicable.

[0012] In the sense of this disclosure, a coil circuit board is understood as a circuit board comprising an insulating carrier material. This insulating carrier material forms the structural basis of the coil circuit board and is typically a non-conductive material.

[0013] At least one coil element is constructed on or within an insulating carrier material. In particular, the coil is not wound as a separate component; for example, it can be integrated into the conductor trace structure of a circuit board, which allows for a more compact form factor and higher efficiency. The coil element can be a planar coil, especially a printed coil. For example, the coil element can be constructed as a receiving coil and / or transmitting coil of an inductive proximity sensor.

[0014] Furthermore, the coil circuit board may also include additional electronic components and corresponding electrical connectors constructed on or within the circuit board, enabling the circuit board to function as a complete electronic circuit module. These additional components may include, for example, signal processing modules, amplifiers, or connection points to ensure the functionality of the coil circuit board within a larger electronic system. This makes the coil circuit board a directly usable complete module, particularly in sensing technology.

[0015] In the sense of this disclosure, flush mounting in a metallic environment can be understood as a mounting method in which the sensor, in particular at least one coil element of the sensor, is flush with the surface of the metallic environment, that is, flush with the edge or surface of a metal housing opening of a machine or device (e.g., a gate device), thereby achieving a compact and mechanically protected structural form. Furthermore, flush mounting may also include the sensor's coil element being at least partially surrounded by metallic material.

[0016] In contrast, in the non-flush mounting of sensors (such as inductive proximity switches), free space is provided around the effective surface. In this case, it can be proposed that the non-flush-mounted sensor protrude slightly from the metallic environment, specifically so that the coil is not surrounded by metallic material.

[0017] The coil circuit board can be arranged in a housing that is at least partially metallic or in a non-metallic housing. In the case of non-flush mounting, the sensor can protrude from the surface of the mounting environment, especially a metallic one, while in the case of flush mounting, the sensor is flush with the (metallic) mounting environment.

[0018] In the sense of this disclosure, a coil element can be understood as a structure consisting of multiple turns of conductive material (e.g., copper). The coil element can be constructed as a planar coil, particularly a printed coil. The coil element is used to generate an electromagnetic field that serves the function of a sensor (e.g., an inductive proximity switch). The coil element is integrated on a coil circuit board and can be distributed across multiple layers of the circuit board. Furthermore, at least one coil element may include at least one transmitting coil and / or at least one receiving coil. The shape of the coil element can be designed as polygonal. At least one receiving coil and at least one transmitting coil can, in particular, be constructed as printed coils. Furthermore, they can be arranged in a layered, stacked manner.

[0019] The coil system has a coil circuit board on which at least one first receiving coil and a transmitting coil are arranged. Here, the first receiving coil comprises a coil designed in a polygonal shape.

[0020] In the sense of this disclosure, a groove or embedment “constructed in an insulating carrier material” can be understood as a recess, pit, or cavity that is part of the insulating carrier material and is used to accommodate other components, especially shielding elements.

[0021] The groove can be achieved in different ways. For example, it can be created in the original solid or pre-fabricated insulating carrier material using subtractive manufacturing methods such as milling, drilling, etching, laser cutting, or waterjet cutting, in which material is removed from the carrier material. Similarly, the term also includes grooves formed in the insulating carrier material through forming processes such as stamping, deep drawing, or embossing. In these methods, the desired recess is created by localized deformation and / or movement of the material without substantial material removal.

[0022] Furthermore, the groove can also be formed as part of the layout during the main manufacturing process of the insulating carrier material. This is the case, for example, with coil circuit boards manufactured by injection molding of plastic materials or by ceramic or composite material casting processes, where the groove can be formed directly during the molding process of the insulating carrier material.

[0023] Crucially, the groove is a structural feature of the insulating carrier material itself, giving it a three-dimensional geometry to accommodate another component. Therefore, it is not merely a cavity formed between separately arranged parts and then filled with a filler material, nor is it simply a structure applied to a surface. This groove or insert ensures precise and stable positioning of the element it houses and contributes to a compact structural form.

[0024] The recess can completely surround the coil element like a trench, enclosing it like an island. Here, the recess extends continuously and uninterruptedly around the coil element, forming a closed ring, especially a circular or polygonal recess. This embodiment enables precise fitting of the shielding element into the milled recess, ensuring optimal shielding of the coil element from electromagnetic interference. Furthermore, new joining techniques and methods can be implemented, for example, when equipping the shielding element into the recess or when equipping the coil circuit board. In the sense of this disclosure, a "precisely matched, pre-formed shielding element arranged in the recess" is understood as a separate component, manufactured independently of the coil circuit board and shaped into its final three-dimensional form before insertion into the recess. "Independent" means that the shielding element is a discrete component, not part of the coil circuit board conductor trace structure (e.g., printed or etched layers on the surface of the coil circuit board). It is not shaped and fixed during assembly by filling voids with a filler material (such as potting compound). Instead, it is treated and installed as a separate object. "Pre-formed" refers to the shielding element having its final or near-final three-dimensional shape (e.g., ring-shaped, sleeve-shaped, or polygonal cylindrical) before being inserted into the recess of the coil circuit board. This pre-formation can be achieved through various manufacturing methods, such as stamping, bending, deep drawing, casting, sintering, or machining (e.g., milling). Typically, this standalone pre-formed shielding element is made of a conductive material, such as copper (Cu), brass (CuZn), or other suitable metal alloys.

[0025] Furthermore, the phrase "precisely matched arrangement of the shielding element within the groove" emphasizes the precise mechanical fit between the pre-formed shielding element and the groove milled into the insulating carrier material. This ensures precise and stable positioning of the shielding element relative to the coil element, resulting in optimal and repeatable shielding. It also allows for accurate matching of the shielding element to the electromagnetic field strength of the coil element, enabling simple, accurate, and repeatable assembly within the groove in the coil circuit board.

[0026] Furthermore, it can be proposed that the shielding element is arranged parallel to at least one layer of the coil circuit board. In the sense of this disclosure, "parallel to at least one coil layer" can mean that the shielding element is arranged in a groove such that, due to the groove's encircling and closed design around the coil element, it is constructed in a trench-like manner. This groove extends through the multi-layered structure of the coil circuit board. The shielding element is arranged such that it lies in a plane that may correspond to at least one layer of the coil circuit board. Depending on the thickness of the shielding element and the depth of the groove, the shielding element can be oriented parallel to multiple layers of the coil circuit board; that is, the shielding element can extend through multiple layers of the coil circuit board, thereby achieving precise shielding throughout the entire coil circuit board.

[0027] Therefore, this shielding element ensures electromagnetic shielding that directly matches the coil elements, thereby optimizing and maximizing the efficiency of electromagnetic shielding for the coil circuit board.

[0028] In the sense of this disclosure, a shielding element can be understood as a conductive component disposed in a recess in a coil circuit board. The shielding element is used to block or reduce electromagnetic interference from the outside and maintain the electromagnetic integrity of the coil element. The shielding element can be made of a conductive material, such as a copper-zinc alloy (e.g., brass (CuZn) or copper (Cu)), and ensures that the coil element operates without interference.

[0029] The technical advantage of the conductive material in the shielding element is that it provides high electromagnetic conductivity, and thus effectively reduces electromagnetic interference. This improves the stability and functionality of the sensor by minimizing the effects of external interference.

[0030] In the sense of this disclosure, conductive materials can be understood as materials with high electrical conductivity specifically designed for shielding electromagnetic fields. Typical materials include copper (Cu) (particularly suitable due to its high conductivity) and brass (CuZn) (which also provides excellent shielding properties). The technical advantage of these materials is that they enable efficient blocking of electromagnetic interference, thereby improving device performance.

[0031] It can also be suggested that the shielding element be arranged as a separate component in the groove of the coil circuit board.

[0032] The technical advantage of using a shielding element as an independent component is that it can be manufactured separately from the coil circuit board and can be precisely embedded into the groove. This simplifies assembly and allows for more flexible selection of materials and components to meet specific requirements.

[0033] In the sense of this disclosure, a separate component can be understood as a separate structural element that is not fixedly integrated into the coil circuit board, but is subsequently embedded into a recess. This enables flexible fabrication of the shielding element, which in turn has the technical effect of allowing different shielding elements to be easily replaced for different applications without having to remanufacture the entire coil circuit board.

[0034] It can also be proposed that the shielding element has a closed shape. This closed shape can be, for example, annular.

[0035] In the sense of this disclosure, a closed shape can be understood as a continuous geometric structure that completely surrounds a coil element. This closed shape can be, for example, a ring shape.

[0036] In the sense of this disclosure, a ring can include circular and polygonal shapes, such as rectangular or square shapes.

[0037] In the sense of this disclosure, a square shape with rounded corners is also considered annular because it fulfills the function of surrounding the shielding element. The technical advantages of this shape are: improved mechanical integration in the circuit board recess, thereby reducing the load during installation, and more stable positioning of the shielding element.

[0038] Furthermore, the technical advantage of a closed-shaped shielding element is that it provides uniform and complete shielding around the coil element. This results in improved shielding because electromagnetic interference can be blocked from all directions. The closed path of the shielding element allows for the induction of a current within it, which helps reduce unwanted electromagnetic fields. This enables the coil element to operate more stably by absorbing and conducting away the interfering field. Thus, the closed path forms a barrier that surrounds the electromagnetic field of the coil element and protects it from external influences.

[0039] Based on these characteristics, the shielding element can be implemented as a short-circuit ring. An additional advantage of the short-circuit ring is that it actively suppresses the electromagnetic field of the coil and effectively shields against unwanted interference through induced current.

[0040] It can also be proposed that the groove and the shielding element have the same closed shape, so the shape of the shielding element corresponds to the shape of the groove. The technical advantage of this shape is that the mechanical integration in the groove of the coil circuit board is improved, thereby reducing the load when installing the shielding element and making the positioning of the shielding element more stable.

[0041] It can also be pointed out that the shielding element is circular.

[0042] In the sense of this disclosure, the term "circle" can include elliptical, near-circular, or perfectly circular shapes.

[0043] It can also be suggested that the shielding element is designed as a polygon.

[0044] In the sense of this disclosure, the term "polygon" can include shapes having straight sides and multiple angles, such as triangles, quadrilaterals, hexagons, or other polygons. The term includes both symmetrical and asymmetrical polygons.

[0045] It can also be suggested that the shielding element be designed as a polygon with rounded corners. The advantage of rounded corners is that they allow for better fit accuracy when the shielding element is embedded in the groove of the coil circuit board. Rounded corners also make mounting the circuit board easier and reduce the risk of mechanical stress or fit errors during assembly.

[0046] It can also be proposed that the coil element is constructed in at least one layer of the coil circuit board. It can also be proposed that a shielding element is arranged in the at least one layer of the coil circuit board.

[0047] The technical advantages of placing the coil element in one or more layers of the coil circuit board are: improved sensitivity and electromagnetic performance of the sensor (e.g., inductive proximity switch) while minimizing space requirements. Integrating the shielding element into the same layer of the coil circuit board enables precise matching between the shielding device and the coil element, further improving shielding efficiency while maintaining a compact circuit board structure.

[0048] In the context of this disclosure, the phrase "in at least one layer of the coil circuit board" can be understood as an arrangement in which the coil elements are integrated into one or more layers of the coil circuit board. This configuration optimizes the electromagnetic characteristics of the coil elements because using one or more layers can increase inductance without increasing space requirements. Furthermore, shielding elements can also be placed in the same layer as the coil elements, thereby achieving precise positioning and alignment of the shielding device with respect to the coil elements without incurring additional structural space requirements.

[0049] By arranging the shielding elements in at least one layer of the coil circuit board, the electromagnetic shielding device is directly integrated into the structure of the coil circuit board. This enhances the shielding effect without increasing the structural space, resulting in a more compact and efficient overall sensor structure.

[0050] It can also be proposed that the surface extension dimension of the coil element can correspond to 70% to 90% of the surface extension dimension of the shielding element. In particular, this ratio can be 75% to 85%, especially 77% to 82%, especially 80%.

[0051] In the sense of this disclosure, the term "the surface extension dimension of the coil element is proportional to the surface extension dimension of the shielding element" can be understood as the proportional relationship between the projected surface of the coil element and the surface of the shielding element. Here, the surface extension dimension of the coil element can be 70% to 90% of the surface extension dimension of the shielding element, of which 75% to 85%, especially 77% to 82%, and especially 80% are considered particularly advantageous.

[0052] The specific ratio of the surface extension dimensions between the coil element and the shielding element has the technical effect of optimally matching the electromagnetic field strength of the coil element with the shielding. This facilitates efficient reduction of electromagnetic interference without affecting sensor sensitivity. The aforementioned size ratio ensures that the shielding element optimally surrounds the coil element, thereby contributing to improved sensor performance, particularly in reducing the effects of edge interference.

[0053] "Surface extension dimension" can refer to the geometric area occupied by the coil element and the shielding element on a common plane. This surface extension dimension considers not only the diameter (for circular or toroidal structures) but also describes the entire two-dimensional surface occupied by the coil element and the shielding element on the coil circuit board, regardless of their shape (e.g., circular, polygonal).

[0054] The technical advantage of this size setting is that the electromagnetic shielding device optimally surrounds the coil element and maximizes shielding efficiency. The precise size ratio effectively shields the electromagnetic field of the coil element without compromising sensor sensitivity. In particular, a more precise control of the electromagnetic field distribution is achieved within the preferred size ratio of 75% to 85%, or 77% to 82%, thereby improving shielding effectiveness and optimizing electromagnetic efficiency.

[0055] Furthermore, the coil circuit board can be constructed to form a sensor of 40 x 40 mm size, such as an inductive proximity switch. The recess can be configured to accommodate a shielding element with a 0.8 x 0.8 mm cross-section. This allows for maximum sensitivity or effective distance, particularly in the center, while promoting lower sensitivity at the edges of the coil circuit board.

[0056] In the sense of this disclosure, a method for manufacturing a coil circuit board includes the following steps: providing a coil circuit board comprising an insulating carrier material and at least one coil element constructed on or in the insulating carrier material; manufacturing a surrounding and closed groove in the insulating carrier material, wherein the groove surrounds the coil element; and inserting a separate pre-formed shielding element into the groove.

[0057] This method is particularly suitable for manufacturing the coil circuit boards described above. Therefore, this method has corresponding advantages and can be improved in a similar way as the coil circuit boards.

[0058] The technical advantages of the manufacturing method are that it allows for the efficient manufacture of the device by precisely inserting the shielding element into a recess in the coil circuit board. Arranging the shielding element in the recess enhances electromagnetic shielding and improves the functionality of the sensor (especially inductive proximity switches). Furthermore, more precise positioning enables a compact structural form and higher product accuracy.

[0059] In the sense of this disclosure, the term "providing" can be understood as a step in the manufacturing process in which the required components, particularly coil circuit boards and coil elements, are prepared in advance and are ready for assembly. The technical effect of this step is to establish a clean starting foundation for subsequent processing steps.

[0060] In the context of this disclosure, the term "constructing a groove" or "manufacturing a groove" refers to a process in which a surrounding and closed recess is created in a coil circuit board by milling or deep milling to accommodate a shielding element. The technical advantage is that it creates a precise and uniform accommodating portion for the shielding element, thereby improving the shielding performance of the sensor.

[0061] In the context of this disclosure, the term "insertion of a shielding element" can be understood as a process in which a shielding element, which may be constructed of a conductive material, is embedded or arranged into a previously constructed groove. The technical effect of positioning the shielding element in the groove is to directly match the electromagnetic shielding device with the coil element, thereby maximizing the shielding efficiency.

[0062] It can also be suggested that, in the sense of this disclosure, the method also includes fixing the shielding element in the groove, particularly by welding.

[0063] In the sense of this disclosure, the term "fixed shielding element" can be understood as a process in which a shielding element is fastened in a groove in a coil circuit board. This can be achieved by various mechanical fastening methods, such as soldering and / or bonding.

[0064] The technical advantage of fixing the shielding element in a groove, especially by welding, is that it establishes a stable mechanical and electrical connection between the coil circuit board and the shielding element, ensuring long-term electromagnetic shielding. This stable connection reduces the risk of movement or displacement of the shielding element during operation, improving the long-term stability and reliability of the sensor.

[0065] In the context of this disclosure, the term "welding" describes a method of securely fixing a shielding element into a groove by means of welding. The technical advantage of welding is that it establishes a mechanically stable connection between the coil circuit board and the shielding element, thereby ensuring reliable shielding and long-term mechanical stability.

[0066] For example, soldering can be achieved by placing one or more soldering surfaces (pads) on the edge of the coil circuit board. Therefore, the shielding components can be spot-soldered.

[0067] It can also be proposed that the coil circuit board in the sense of this disclosure is used in inductive proximity switches designed for flush mounting in a metallic environment.

[0068] The technical advantage of this device in its application as an inductive proximity switch flush-mounted in a metallic environment is that the sensor can be seamlessly integrated into the metallic mounting environment without any protrusions. This allows for a compact design that protects the sensor from mechanical damage while ensuring accurate identification of metallic objects. The inductive proximity switch detects the approach of a metallic object and triggers the switching function without direct contact. The technical advantage of this switch is that it enables reliable detection in industrial applications where mechanical operation is inapplicable.

[0069] In other words, the above description can be summarized as a possible more specific design of this disclosure as described below, wherein the following description should not be regarded as a limitation of this disclosure.

[0070] A coil is a component of an inductive proximity switch and is embedded to emit and evaluate electromagnetic fields. The coil can be constructed not only using wound copper wire but also using printed circuit board technology with printed copper conductor traces. Inductive proximity switches have two different implementations: flush mounting in metal; and non-flush mounting with a non-metallic area surrounding the sensor coil.

[0071] According to this disclosure, a flush coil system should be provided that meets all requirements for flush mounting in a metallic environment, and particularly provides a cost-optimized solution in terms of the internal structure and fabrication of the sensor. All requirements for cost-optimized fabrication of a flush-mounted sensor are met by positioning and securing a shielding element (e.g., a short-circuit ring) into a recess (e.g., a deep-milled portion) of the coil using printed circuit board technology.

[0072] In the context of this specification, a coil system may include one or more coils integrated on a coil circuit board, as well as other components for signal processing and shielding. Here, the coil system includes at least one receiving coil and / or at least one transmitting coil. Furthermore, the coil system includes not only the coil or coil element itself, but also the necessary leads for associated electronics to enable accurate identification and processing of electromagnetic fields. Such systems are particularly important in sensors to ensure stable and accurate measurements.

[0073] To enable flush mounting of inductive sensors, the coil needs to be shielded from the sensor's metallic mounting and structural environment via a conductive isolation device inside the sensor. This is ensured by a shielding element (e.g., a shielding ring and / or a short-circuit ring) made of CuZn or Cu surrounding the coil. Typically, this shielding device is a closed ring placed in the front cap around the coil / coil circuit board. A drawback of this solution is that the secure connection and positioning of the shielding element within the front cap is not guaranteed when the ring is inserted. Secure connection and positioning are achieved in subsequent manufacturing processes through additional steps (e.g., filling the front cap with potting resin, or securing the shielding element by adhesive bonding or plastic overlay).

[0074] In the prior art, either standard shielding devices (such as shielding rings) are placed around the coil and fixed with potting compound, or shielding can be achieved by edge metallization in the printed coil circuit board.

[0075] The disadvantages of existing implementations using standard shielding devices (such as shielding rings) are as follows: the lack of fixed positioning before potting makes transporting and handling of the unpotted component difficult in subsequent manufacturing processes. Furthermore, the smaller copper thickness in edge metallization is disadvantageous because it cannot provide the same level of shielding for flushing as a solid Cu ring or CuZn ring.

[0076] According to this disclosure, a novel structure is implemented for a coil circuit board with a shielding element, particularly a shielding ring. Here, a deep milled portion or groove is introduced into the coil circuit board in the direction towards the effective sensor surface (bottom of the front cap), and the shielding element is placed into this deep milled portion or groove and thus fixedly positioned. This achieves fixed positioning of the shielding element relative to the coil element or the coil circuit board. During fabrication, potting can be used to fill the coil circuit board, thereby ensuring the final fixation of the shielding element in the groove. This positioning of the shielding element achieves optimal shielding for the coil system and allows for fixation within the front cap without additional fabrication steps.

[0077] One embodiment of this disclosure is a single-board embodiment, in which the coil system and circuitry are mounted on a single board. Here, the shielding element (e.g., in the form of a short-circuit ring) is particularly implemented as square and inserted into the deep-milled portion parallel to the front copper layer where the coil system is arranged.

[0078] According to another embodiment of this disclosure, the coil circuit board and the electronic circuit board are separate. In this case, the short-circuit ring is implemented as a circle and positioned in the deep-milled portion at its maximum diameter for shielding.

[0079] Furthermore, embodiments according to this disclosure may be implemented as follows: as a coil circuit board, as a complete sensor circuit board (the coil system includes electronic circuitry), as a sensor in a plastic housing (which is used for internal shielding in a flush sensor), and as a sensor in a cylindrical metal housing, so that the assembly can be manufactured at a lower cost through simplified joining techniques.

[0080] Compared to existing technologies, its advantages lie in the fact that by shielding the coil only at the height of the coil system using a shielding element (such as a short-circuit ring), the maximum propagation of the electromagnetic field can be optimally utilized. Therefore, the maximum operating distance can be achieved. Direct positioning and fixation can be achieved during assembly by positioning the shielding element (such as the short-circuit ring) in a recess (deep milling) in the coil circuit board. This is a major advantage of the device in terms of bonding technology. New bonding technologies and methods include, for example, equipping the shielding element during circuit board assembly and fixing the shielding element (short-circuit ring) by welding after positioning it on the sensor front cap.

[0081] The aforementioned design schemes and improvements can be combined with each other arbitrarily where meaningful. Other possible design schemes, improvements, and implementations of this disclosure include combinations of features not explicitly mentioned in the prior or subsequent descriptions of improvements in this disclosure. Those skilled in the art can also add individual aspects as improvements or supplements to the corresponding basic form of this disclosure. The features of the device claims can be implemented and / or carried out through corresponding functions, thereby supplementing or extending the method. Furthermore, the method steps can be implemented through corresponding implementation modules in the device. Therefore, the foregoing description of the device also applies similarly to the method, and vice versa. Attached Figure Description

[0082] Other details and advantages of the invention will now be explained in detail with the aid of embodiments shown in the accompanying drawings.

[0083] In the attached diagram:

[0084] Figure 1 A schematic diagram of a first embodiment of the coil circuit board is shown;

[0085] Figure 2 A schematic diagram showing a first embodiment without shielding elements;

[0086] Figure 3 A schematic diagram of a second embodiment of the coil circuit board is shown;

[0087] Figure 4 A schematic diagram of a third embodiment of the coil circuit board is shown;

[0088] Figure 5 A schematic diagram of a fourth embodiment of the coil circuit board is shown;

[0089] Figure 6 A schematic diagram of a single layer of a first embodiment of a coil circuit board and a section axis A are shown;

[0090] Figure 7 A cross-sectional schematic diagram of the first embodiment of the coil circuit board is shown;

[0091] Figure 8 A flowchart of the method according to this disclosure is shown. Detailed Implementation

[0092] The accompanying drawings should provide a further understanding of the improvements made to this disclosure. They illustrate the improvements and serve to illustrate the principles and concepts of this disclosure in conjunction with the specification. Other improvements and many of the mentioned advantages are derived from the drawings. The elements in the drawings are not necessarily shown to scale.

[0093] In the accompanying drawings, identical, functional, and / or operating elements, features, and components are correspondingly given the same reference numerals unless otherwise described in detail.

[0094] Figure 1 A schematic diagram of a first embodiment of the coil circuit board 101 is shown.

[0095] The coil circuit board 101 includes an insulating carrier material.

[0096] Furthermore, the coil element 102 is constructed on or within the insulating carrier material of the coil circuit board 101.

[0097] In all the examples shown in the accompanying drawings, the coil element 102 may be configured accordingly as a receiving coil or a transmitting coil of an inductive proximity sensor.

[0098] The coil element 102 is designed to be both circular and spiral.

[0099] The coil element 102 can also be formed into other helical shapes. For example, Figure 5 The diagram shows a rhomboid coil element 102. Alternatively, other polygonal embodiments are also possible.

[0100] In another embodiment, the coil element 102 can actually take any shape, as long as the coil element is arranged within the groove 103 and the shielding element 104.

[0101] In this embodiment, the coil element 102 is configured as a planar coil.

[0102] In another embodiment not shown, the coil element 102 may be implemented as a printed coil.

[0103] In the insulating carrier material of the coil circuit board 101, a surrounding and closed groove 103 is milled or constructed around the coil element 102.

[0104] The groove 103 can be formed, for example, by milling or deep milling.

[0105] The shielding element 104 is positioned in the groove 103 and is used to provide electromagnetic shielding for the coil element 102.

[0106] In this embodiment, the groove 103 forms a square annular region around the coil element 102.

[0107] The shielding element 104 is formed correspondingly to the groove 103. In particular, the shielding element 104 is also constructed in a closed and circumferential manner, for example, it is constructed as a square ring.

[0108] The shielding element 104 forms, for example, a short-circuit ring and is used for electromagnetic shielding of the coil element 102. This applies to all embodiments described in the specification.

[0109] Figure 2 Another embodiment of the coil circuit board is shown.

[0110] exist Figure 2 The schematic diagram shows a first embodiment without shielding element 104.

[0111] Without the shielding element 104, the coil circuit board 101 shows a closed, surrounding groove 103.

[0112] In the coil circuit board 101, a surrounding and closed groove 103 is arranged around the coil element 102. The groove 103 is formed as a "trench" type around the coil element 102. The groove 103 of this embodiment, as well as the grooves of all embodiments in the specification, can realize the following new bonding techniques / methods, for example, equipping the coil circuit board 101 with a shielding element 104.

[0113] The coil element 102 is implemented, for example, as a printed planar coil and is designed to be circular, especially spiral.

[0114] The groove 103 completely surrounds the coil element 102 and is configured to accommodate the shielding element 104.

[0115] The groove 103 specifies the shape of the shielding element 104 or the short-circuit ring, because the shielding element 104 is arranged in the groove 103.

[0116] Figure 3A schematic diagram of the second embodiment of the coil circuit board 101 illustrates another embodiment.

[0117] The coil element 102 is also circular and spiral in shape.

[0118] The coil element 102 is a planar coil and can also be constructed, for example, as a printed coil.

[0119] The surrounding groove 103 surrounds the coil element 102, wherein the shielding element 104 is arranged in the groove 103 to ensure uniform electromagnetic shielding.

[0120] The groove 103 and the shielding element 104 are provided with rounded corners.

[0121] The rounded corners of the groove 103 and the shielding element 104 ensure more precise fit within the coil circuit board 101. The rounded corners reduce the risk of mechanical stress or fit errors during assembly and simplify the insertion of the shielding element into the groove.

[0122] Figure 4 A schematic diagram of the third embodiment of the coil circuit board 101 illustrates another embodiment.

[0123] The groove 103 is designed to be polygonal. In particular, the polygonal groove... Figure 4 The groove 103 is specially designed as a hexagonal groove.

[0124] The groove 103 extends around the coil element 102, which has a circular and spiral design.

[0125] The shielding element 104 is located within the hexagonal recess 103 and, like the recess 103, is also designed to be polygonal. In particular, the polygonal shielding element... Figure 4 The hexagonal shape of the shielding element 104 is specifically shown. The shielding element is used to provide electromagnetic shielding for the coil element 102.

[0126] The polygonal shape of the shielding element 104 enables stable positioning in the groove 103 and provides uniform shielding.

[0127] This embodiment shows that the shielding element 104 can also be other polygonal shapes, such as pentagonal or polygonal shapes. This is in Figure 4 For example, an implementation scheme using a hexagon is shown.

[0128] Figure 5 A schematic diagram of the fourth embodiment of the coil circuit board 101 illustrates another embodiment.

[0129] The coil circuit board 101 includes a coil element 102, which is designed to be both rhomboid and spiral.

[0130] In other embodiments, the rhomboid coil element 102 may be used alternatively or in combination with circular and spiral coil elements 102, such that the groove 103 and the shielding element 104 surround the coil element 102 in any closed and encircling shape.

[0131] The groove 103 is designed to be circular.

[0132] A shielding element 104 is arranged in the circular groove 103, and the shielding element also has a circular design.

[0133] The circular implementation is, for example, a special shape of a ring structure.

[0134] The circular structure of the shielding element 104 provides uniform shielding around the coil element 102 because the continuous shape effectively reduces electromagnetic interference from all directions. This results in improved stability and sensitivity of the sensor, as there are no unprotected areas and the electromagnetic shielding is optimized.

[0135] Figure 6 A schematic diagram of a single layer of a first embodiment of a coil circuit board and a section axis A are shown.

[0136] Figure 6 The image exemplarily shows layer 106 of a coil circuit board.

[0137] Also shown is a portion of a coil circuit board 101 having a schematically shown rectangular shielding element 104 that surrounds the coil element 102.

[0138] The coil element 102 is arranged in layer 106 of the coil circuit board 101.

[0139] The shielding element 104 and the groove 103 are arranged in the same layer and are responsible for directly shielding the coil element 102.

[0140] Figure 7 Show along Figure 6 A cross-sectional view along section axis A is shown in the diagram. This example relates to a first embodiment of the coil circuit board 101. Any other embodiment may also be shown along section axis A.

[0141] The figure illustrates another embodiment of a coil circuit board 101 having a coil element 102 and a plurality of wire turns 112, the coil element being constructed in at least one of layers 106, 116, 126, 136 of the coil circuit board 101.

[0142] like Figure 6 As shown, the layers of coil element 102 are designed to be circular, therefore in Figure 7In the illustration, the cross-section of the coil circuit board 101 is symmetrically constructed.

[0143] The coil element 102 is constructed symmetrically, and two cross-sections of the coil element 102’s coil turns 112 are shown respectively.

[0144] The shielding element 104 and the groove 103 are also constructed symmetrically.

[0145] The coil circuit board 101 consists of multiple layers, including copper layers 106, 116, 126, 136, 146, and 156, in which conductive wire turns 112 of the coil element 102 are constructed. These copper layers may also contain conductive material that forms the wire turns of other coil elements 132 and 142.

[0146] The coils of the other coil elements 132 and 142 can also be constructed as the coil 112 of the same coil element 102. Therefore, the shielding element 104 is arranged in the groove 103 at the height of the coil 112 in layers 106, 116, 126, and 136, and the coils of the other coil elements 132 and 142 are not surrounded by the groove 103 and the shielding element 104.

[0147] The thin film between layers 106, 116, 126, 136, 146, and 156 can, for example, be used as an insulating film. Additional conductive areas for contact wire turns and other components can be arranged within these insulating films.

[0148] This multi-film arrangement allows for a compact structure without compromising electromagnetic shielding of the shielding element 104 located in the groove 103.

[0149] The coil element 102 is constructed in multiple layers and includes at least two coil layers, particularly four coil turns 112 located in layers 106, 116, 126, and 136.

[0150] The shielding element 104 and the groove 103 are configured to be parallel to the coil element 102. For example... Figure 7 As shown more clearly, the shielding element 104 is arranged parallel to at least one layer 106, 116, 126, 136 of the coil element 102 or the coil circuit board 101. This means that the recess 103 is constructed in a trench-like manner to surround and close around the coil element 102. Therefore, the recess 103 penetrates the multilayer structure of the coil circuit board 101 and the multilayer configuration of the coil element 102. Consequently, the shielding element 104 is arranged such that it lies in at least one plane corresponding to at least one plane of the layers 106, 116, 126, 136 of the coil circuit board, and thus the shielding element is arranged parallel to these layers or additional layers 146, 156. Thus, the shielding element 104 is configured to be parallel to the coil element 102.

[0151] According to the implementation scheme, the shielding element 104 can extend through multiple layers 106, 116, 126, 136 of the coil circuit board 101, depending on the thickness or height of the shielding element 104 and the depth of the groove 103, thereby enabling precise shielding of the wire turns 112 located in the layers 106, 116, 126, 136 of the coil circuit board 101.

[0152] Therefore, the shielding element 104 ensures electromagnetic shielding that is directly matched with the coil element 102, thereby optimizing and maximizing the efficiency of electromagnetic shielding of the coil circuit board 101.

[0153] In particular, the shielding element 104 and the groove 103 are constructed such that the shielding element and the groove are constructed through multiple layers 106, 116, 126, 136.

[0154] Here, the multilayer coil element 102, which has coil turns 112 located in layers 106, 116, 126, and 136, is surrounded by a shielding element 104 and a groove 103.

[0155] Layers 146 and 156, which have additional coil elements 132 and 142, are not surrounded by shielding element 104 and groove 103.

[0156] The other coil elements 132 and 142 may, for example, be multiple turns of another coil element.

[0157] The multilayer coil element 102 with coil turns 112 and other coil elements 132, 142 may be, for example, a transmitting coil and / or a receiving coil, respectively.

[0158] This configuration demonstrates how the shielding element 104 can be precisely positioned relative to the multilayer coil element 102 with coil turns 112, ensuring optimal electromagnetic shielding without increasing space requirements.

[0159] The multilayer arrangement of coil elements 102 improves the sensitivity and electromagnetic performance of the sensor (e.g., an inductive proximity sensor), while shielding elements 104 are integrated in a manner that precisely crosses multiple layers 106, 116, 126, 136 of the coil circuit board 101.

[0160] In another embodiment not shown in the accompanying drawings, the shielding element 104 and the groove 103 may also be configured to reach deeper layers 146, 156.

[0161] Furthermore, in another embodiment not shown, the recess 103 is configured to be deeper than the height of the shielding element 104. This means, for example, that the recess 103 can be configured to extend from the surface 108 of the coil circuit board 101 to the layer 156, wherein the shielding element 104 is configured to extend only from the layer 126 to the layer 156.

[0162] Figures 1 to 7 The coil circuit board is designed as a flush-mountable inductive proximity sensor, particularly a flush-mountable inductive proximity sensor in a metallic environment, wherein shielding of the coil element 102 is achieved by a shielding element 104 at the height of the coil element 102. This optimally utilizes the maximum propagation of the electromagnetic field, thereby achieving the maximum operating distance.

[0163] Furthermore, the coil element 102 can take on different shapes, such as a combination of spiral and circular and diamond designs. The positioning of the shielding element 104 in the recess 103 of the coil circuit board 101 enables direct and precise fixation during assembly.

[0164] In the embodiments, the groove 103 is constructed by milling or deep milling.

[0165] This is the main advantage of the equipment in terms of bonding technology. New bonding technologies and methods (such as embedding shielding elements when assembling circuit boards, and fixing shielding elements by welding after positioning in the sensor's front cap) further contribute to improved production accuracy and stability.

[0166] Figure 8 A flowchart of the method according to this disclosure is shown.

[0167] A schematic overview of the entire fabrication process of the coil circuit board 101 is shown in particular. The process begins at step 210, whereby a coil circuit board 101 comprising an insulating carrier material and a coil element 102 is provided, wherein the coil element 102 is constructed on or within the insulating carrier material. In the next step 220, a surrounding and closed recess 103 is manufactured or constructed in the coil circuit board 101, wherein the recess 103 surrounds the coil element 102. In a further step 230, a separate pre-formed shielding element 104 is inserted into the recess 103, or the shielding element 104 is arranged into the recess 103.

[0168] In a further step 240 of this embodiment, the shielding element 104 is fixed in the groove 103 to ensure stable and reliable positioning, for example by welding.

[0169] This example illustrates a schematic process that demonstrates an efficient and precise method for manufacturing coil circuit boards. New bonding techniques and methods, such as embedding shielding elements during the mounting and securing of the coil circuit boards, further contribute to improved production accuracy and stability.

[0170] List of reference numerals

[0171] 101 Coil Circuit Board

[0172] 102 coil element

[0173] 103 grooves

[0174] 104 shielding element

[0175] Floors 106, 116, 126, 136, 146, 156

[0176] 108 surface

[0177] 112 line turn

[0178] 132, 142 Other coil elements

[0179] 200 Methods for Manufacturing

[0180] Methods and steps 210 to 240.

Claims

1. A coil circuit board (101), particularly for use in an inductive proximity switch, the coil circuit board being particularly suitable for flush mounting in a metallic environment, the coil circuit board comprising: - Insulating carrier material; - At least one coil element (102) is constructed on or in the insulating carrier material; - A surrounding and closed groove (103) constructed in the insulating carrier material, surrounding the coil element (102); and - Independent pre-formed shielding elements (104) are precisely matched and arranged in the groove (103).

2. The coil circuit board (101) according to claim 1, characterized in that, The shielding element (104) is constructed of a conductive material, particularly brass (CuZn) or copper (Cu).

3. The coil circuit board (101) according to any one of the preceding claims, characterized in that, The shielding element (104) is arranged as an independent component in the groove (103) of the coil circuit board (101).

4. The coil circuit board (101) according to any one of the preceding claims, characterized in that, The shielding element (104) has a closed shape, especially a ring shape.

5. The coil circuit board (101) according to claim 4, characterized in that, The groove (103) and the shielding element (104) have the same closed shape, so the shape of the shielding element (104) corresponds to the shape of the groove (103).

6. The coil circuit board (101) according to claim 4, characterized in that, The shielding element (104) is circular.

7. The coil circuit board (101) according to claim 4, characterized in that, The shielding element (104) is polygonal.

8. The coil circuit board (101) according to claim 7, characterized in that, The shielding element (104) is constructed as a polygon with rounded corners.

9. The coil circuit board (101) according to any one of the preceding claims, characterized in that, The coil elements (102; 112, 122, 132, 142) are constructed in at least one layer (106, 116, 126, 136, 146, 156) of the coil circuit board (101), and the shielding element (104) is arranged in the at least one layer (106, 116, 126, 136, 146, 156).

10. The coil circuit board (101) according to any one of the preceding claims, characterized in that, The surface extension dimension of the coil element (102) corresponds to 70% to 90% of the surface extension dimension of the shielding element (104).

11. A method (200) for manufacturing a coil circuit board (101) according to any one of the preceding claims, the method comprising the steps of: - Provides (210) a coil circuit board (101), the coil circuit board comprising an insulating carrier material and at least one coil element (102) constructed on or in the insulating carrier material. - A surrounding and closed groove (103) is formed (220) in the insulating carrier material, wherein the groove (103) surrounds the coil element (102); and - Insert the individual pre-formed shielding element (104) into the groove (103) (230).

12. The method according to claim 11, further comprising: - The shielding element (104) is fixed (240) in the groove (103), especially by welding.

13. Use of the coil circuit board (101) according to any one of claims 1 to 10 in an inductive proximity switch designed for flush mounting in a metallic environment.

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