Coil device

Abstract

The utility model relates to the technical field of wireless charging, and discloses a coil device which comprises a flexible substrate, one side of the flexible substrate is connected with a working coil formed by die cutting according to a preset circuit pattern, the other side of the flexible substrate is connected with a composite magnetic isolation sheet, the working coil is arranged in a multi-strand parallel plane circuit mode, and the composite magnetic isolation sheet is arranged on the flexible substrate. The side, facing the flexible substrate, of the working coil and the side, deviating from the flexible substrate, of the working coil are both planes, the side, deviating from the flexible substrate, of the working coil is connected with an insulating film layer, and the composite magnetism isolating sheet comprises a plurality of first bonding layers and magnetism isolating layers which are alternately arranged; the plurality of first bonding layers and the magnetic isolation layers are pressed on the flexible substrate in a vacuum mode, and the first bonding layers are connected with the adjacent magnetic isolation layers and are connected with the flexible substrate and the magnetic isolation layers. According to the thin and small coil device, the performance requirements of high Q value and low resistance are met, and the energy transmission power and the cost performance of the thin and small coil device are improved.

Description

Technical Field

[0001] The present application relates to the technical field of wireless charging, and in particular to a coil device. Background Art

[0002] As consumers' demands for convenient, safe and personalized experience increase, traditional wireless charging devices can no longer meet the needs of modern ultra-thin devices. In traditional technologies, wireless charging coils usually use copper winding technology and FPC (Flexible Printed Circuit) technology to form coils by winding multiple layers of copper wire. This solution performs well in signal transmission and electromagnetic compatibility, but the copper winding solution requires a more complex manufacturing process, and the thickness and compactness of the copper winding are limited by the copper wire material, making it difficult to achieve an extremely compact design. The WPC coil combined with FPC technology also cannot meet the aforementioned ultra-thin requirements. This situation needs to change. Utility Model Content

[0003] In view of this, the present application provides a coil device to solve the technical problem mentioned above.

[0004] To achieve the above objectives, the technical solutions adopted are:

[0005] A coil device comprises a flexible substrate, one side of the flexible substrate is connected to a working coil formed by die-cutting according to a preset circuit pattern, the other side of the flexible substrate is connected to a composite magnetic isolation sheet, the working coil is arranged in a planar circuit with multiple strands connected in parallel, the side of the working coil facing the flexible substrate and the side away from the flexible substrate are both planes, and the side away from the flexible substrate is connected to an insulating film layer, the composite magnetic isolation sheet comprises a plurality of alternately arranged first adhesive layers and magnetic isolation layers, a plurality of the first adhesive layers and the magnetic isolation layers are vacuum pressed on the flexible substrate, the first adhesive layer connects adjacent magnetic isolation layers, and connects the flexible substrate and the magnetic isolation layer.

[0006] The present application is further configured as follows: the working coil includes a plurality of parallel-connected wire turns, each of the wire turns has the same set row spacing, and the set row spacing is ≥10 um.

[0007] The present application is further configured as follows: the first adhesive layer includes a PSA pressure-sensitive adhesive material layer, and the magnetic isolation layer includes at least one of a nanocrystalline material layer, a ferrite material layer, and an absorbing material layer.

[0008] The present application is further configured as follows: the flexible substrate is further provided with an auxiliary coil, and the auxiliary coil is wound on the flexible substrate outside the working coil.

[0009] The present application is further configured as follows: the flexible substrate includes a polyimide PI material or a polyester PET film material.

[0010] The present application is further configured as follows: a differential feeding gold finger is provided on the flexible substrate, the differential feeding gold finger includes a first pad and a second pad, and two ends of the working coil are connected to the first pad and the second pad respectively.

[0011] The present application is further configured as follows: a first single-sided jumper point is provided at one end of the first pad facing the flexible substrate, a second single-sided jumper point is provided at one end of the second pad facing the flexible substrate, and two ends of the working coil are respectively connected to the first single-sided jumper point and the second single-sided jumper point.

[0012] The present application is further configured as follows: the differential feeding gold finger includes a third pad and a fourth pad, and two ends of the auxiliary coil are connected to the third pad and the fourth pad respectively.

[0013] The present application is further configured as follows: a third single-sided jumper point is provided at one end of the third pad facing the flexible substrate, a fourth single-sided jumper point is provided at one end of the fourth pad facing the flexible substrate, and two ends of the auxiliary coil are respectively connected to the third single-sided jumper point and the fourth single-sided jumper point.

[0014] The present application is further configured as follows: the working coil includes a WPC coil, and the auxiliary coil includes an NFC coil; the flexible substrate, the working coil, and the auxiliary coil are all wrapped by a packaging composite layer with a set dielectric constant, and the overall thickness of the coil device is ≥0.17 mm.

[0015] In summary, compared with the prior art, the present application discloses a coil device, including a flexible substrate and working coils and a composite magnetic isolation sheet on both sides of the flexible substrate. The working coil is arranged in a planar circuit with multiple strands connected in parallel, and the side facing the flexible substrate and the side away from the flexible substrate are both planes. The composite magnetic isolation sheet includes a plurality of alternatingly arranged first adhesive layers and magnetic isolation layers, and the plurality of first adhesive layers and magnetic isolation layers are vacuum pressed on the flexible substrate, wherein the first adhesive layer connects adjacent magnetic isolation layers, and connects the flexible substrate and the magnetic isolation layer. That is, through the above arrangement, the requirements for thinning and miniaturization of the coil device are met, the performance requirements for high Q value and low resistance are met, and the energy transmission power and preparation cost-effectiveness of the coil device are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0017] Figure 1 is the process flow diagram of the preparation method of the coil device in this embodiment;

[0018] Figure 2 is the structural change diagram of the preparation of the coil device in this embodiment;

[0019] Figure 3 is the cross-sectional structural schematic diagram of the coil device in this embodiment;

[0020] Figure 4 is the structural schematic diagram of the first coil device in this embodiment;

[0021] Figure 5 is the structural schematic diagram of the second coil device in this embodiment. Detailed implementation manners

[0022] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0023] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusively, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanations in the specific embodiments or further in combination with the context in the specific embodiments.

[0024] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] In the following description, suffixes such as "module", "component", or "unit" used to denote elements are only for the convenience of describing the present application and have no specific meaning in themselves. Therefore, "module", "component", or "unit" can be used interchangeably.

[0026] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0027] The technical solution shown in the present application will be described in detail below through specific embodiments. It should be noted that the description order of the following embodiments does not limit the priority order of the embodiments.

[0028] Please refer to Figure 1 、 Figure 2 and Figure 3 , the present application provides a method for preparing a coil device to prepare a coil device. The method for preparing a coil device includes:

[0029] S101, provide a flexible substrate 1 and connect a copper rolling layer 2 to the flexible substrate 1.

[0030] In this step, the flexible substrate 1 and the copper rolling layer 2 are combined as the base material preparation of the coil device, so as to form a multi-strand parallel planar working coil with high conductivity, stability and controllable thickness in the subsequent preparation steps. It can be understood that copper has excellent conductivity. By connecting the copper rolling layer 2 to the flexible substrate 1, it can ensure that the subsequent formed working coil has low loss and high-efficiency conductive performance when transmitting electric energy. And forming a working coil based on the copper rolling layer 2 not only has rigidity and stability, but also can maintain the flexible characteristics of the flexible substrate, so as to adapt to different-shaped circuit designs.

[0031] Among them, the flexible substrate 1 includes polyimide PI material or polyester PET film material. The polyimide PI material has excellent high-temperature resistance and can remain stable in extreme environments, which is very important for the long-term reliable operation of high-power wireless charging devices. At the same time, the polyimide PI material has good dielectric constant and insulation performance, as well as high mechanical strength and flexibility, thus ensuring the performance and life of the flexible substrate 1; on the other hand, the polyester PET film material also has good mechanical properties and electrical insulation performance, and its material has high transparency and strong ultraviolet resistance, and is also suitable for low-temperature working conditions.

[0032] In one embodiment, a copper rolling layer 2 is connected to the flexible substrate 1, which specifically may include:

[0033] Provide a copper foil;

[0034] Roll the copper foil into a copper rolling layer 2 with a set rolling thickness through a rolling process, wherein the set rolling thickness H≥35um;

[0035] Fill an adhesive between the flexible substrate 1 and the copper rolling layer 2 to form a second adhesive layer 3.

[0036] Then the copper rolling layer 2 is formed by rolling the copper foil and is tightly connected to the flexible substrate 1 through the second adhesive layer 3. Among them, based on the design of the set rolling thickness H≥35um, while meeting the requirements of the ultra-thin coil device, it ensures that the copper rolling layer 2 has sufficient electrical conductivity, mechanical strength and durability. Specifically, H≥35um of the copper rolling layer 2 can effectively reduce the resistance, ensuring that the working coil formed subsequently has a sufficiently low resistance when transmitting current, thereby reducing energy loss and improving transmission efficiency. H≥35um of the copper rolling layer 2 can ensure the structural stability of the copper layer during processing and use, and also ensure good processing accuracy and consistency during subsequent die-cutting processing, avoiding unevenness or edge burr problems of the copper layer during die-cutting.

[0037] It should be noted that based on the design of the set rolling thickness H≥35um, the fatigue resistance and durability of the copper rolling layer 2 can be improved, reducing material fatigue or cracking caused by repeated bending, vibration or thermal expansion and contraction.

[0038] In one embodiment, the second adhesive layer 3 includes acrylic adhesive.

[0039] S102, die-cut the copper rolling layer 2 according to a preset circuit pattern to form a working coil 4 on the flexible substrate 1, and the working coil 4 is arranged as a multi-strand parallel planar circuit.

[0040] In this step, the preset of the die-cutting pattern can be carried out according to actual environmental requirements and design requirements, that is, die-cut the copper rolling layer 2 according to the preset circuit pattern.

[0041] Specifically, the pattern and size of the die-cutting tool can also be designed according to the circuit design requirements, so as to die-cut the copper rolling layer 2 into the required shape and circuit. Among them, an accurate die mold for die-cutting is made according to the design drawing, and the accuracy of the die mold directly affects the die-cutting accuracy, that is, using a precision mold to cut the material to achieve a specific shape and size.

[0042] Among them, the die-cutting process also includes a punching process. Specifically, the punching process is integrated with automated equipment, which can quickly and efficiently process large quantities of copper rolled layers 2 and complete the cutting and forming of a large number of coils in a short time. That is, the punching process accurately cuts the required working coil shape on the copper rolled layer 2 according to the preset circuit pattern, ensuring that the size and shape of the circuit meet the design requirements.

[0043] Based on the setting of H≥35um of the aforementioned copper rolled layer 2 and combined with the multi-strand parallel planar circuit setting of the working coil 4, it can effectively cope with the skin effect of high-frequency current (when the current frequency increases, the current tends to flow through the surface of the conductor, rather than being evenly distributed over the entire cross-section). The multi-strand parallel design effectively distributes the current to multiple parallel conductors. The increase in resistance of the overall circuit will also be offset by the total effect of the parallel conductors, reducing the current density of a single circuit, making the current distribution more uniform, while achieving the high Q value and low resistance requirements of the coil device, and realizing the ultra-thin requirements of the coil device.

[0044] In one embodiment, the side of the working coil 4 facing the flexible substrate 1 and the side away from the flexible substrate 1 are both planes. The planar circuit setting has a larger surface area than the circular cross-section conductor. Under high-frequency conditions, more current can flow through the surface of these planar circuits, maximizing the effective utilization of the conductor, thereby reducing the increase in resistance caused by the skin effect. Specifically, the multi-strand parallel planar circuit setting of the working coil 4 has an effective copper cross-sectional area that is 20-30% larger than the circular cross-section of the multi-strand copper winding, which can meet the requirements of larger energy transmission power and ultra-thin coil devices.

[0045] In one embodiment, reference Figure 4 or Figure 5 The working coil 4 includes a plurality of parallel turns, each of which has the same set row spacing K, and the set row spacing K is ≥ 10um, then the same set row spacing K and the set row spacing K ≥ 10um ensure that the current distribution between each turn is uniform, reduce performance problems caused by electromagnetic interference between turns, reduce mutual interference between adjacent turns, improve the overall current transmission efficiency, and reduce interference caused by electromagnetic coupling between turns, especially in high-frequency applications, such as electromagnetic interference between turns may cause signal distortion or efficiency reduction problems, and based on this setting, the electromagnetic compatibility of the coil can also be improved, reducing the impact of external electromagnetic interference on coil performance, and can also improve design flexibility, so that the working coil 4 can adapt to different electrical and mechanical requirements in various application scenarios.

[0046] In one embodiment, the working coil 4 includes multiple turns of wire connected in parallel, and there is the same set row spacing K between each turn, where the set row spacing K = 10 μm, so as to optimize current transmission, reduce interference, and optimize the volume of the coil device while ensuring the performance of the working coil 4.

[0047] It should be noted that the working coil 4 of this embodiment is obtained by die-cutting according to a preset circuit pattern, which reduces the use of chemical potions in traditional copper winding technology and FPC etching technology, is more environmentally friendly while saving production costs.

[0048] S103, vacuum hot-press the working coil 4 coated with an insulating material to form an insulating film layer 5 on the working coil 4.

[0049] In this step, an insulating film layer 5 is generated on the working coil 4 by vacuum hot-pressing, effectively preventing electrical short circuits between the turns of the working coil 4 and between the working coil 4 and other circuit components, protecting the coil device from external electrical interference, and improving the overall electrical safety of the device.

[0050] Moreover, the insulating film layer 5 has high temperature resistance, can withstand the high temperature environment in high-power applications, avoid material failure due to overheating, and can also prevent the erosion of moisture and corrosive substances on the working coil 4, extending the service life of the coil; and through the vacuum hot-pressing method, it can ensure that the insulating film layer 5 evenly covers the surface of the working coil 4, avoiding performance problems caused by uneven coating. At the same time, the vacuum hot-pressing precisely controls the thickness of the insulating film layer 5 to ensure that the film layer meets the design requirements and avoids insulation performance problems caused by being too thin or too thick. After vacuum hot-pressing, the insulating film layer 5 can be tightly combined with the working coil 4, and air bubbles and impurities are removed through the vacuum process, enhancing the durability and stability of the insulating film layer 5.

[0051] On the other hand, the insulating film layer 5 can effectively isolate high-frequency signals, reduce electromagnetic interference, improve the electromagnetic compatibility of the working coil 4, can reduce energy loss caused by current leakage and poor insulation, and improve the overall efficiency of the working coil 4, that is, the insulating film layer 5 enables the working coil 4 to have good anti-aging performance, can maintain stable performance during long-term use, enables the working coil 4 to still maintain reliable performance in harsh environments, and enhances the overall reliability of the product.

[0052] It should be noted that based on the aforementioned die-cut copper rolling layer 2 to form the working coil 4 on the flexible substrate 1, vacuum hot-pressing coating after die-cutting can ensure that the insulating material precisely covers every part of the working coil 4, and the insulating film layer 5 can protect the working coil 4 from external damage during subsequent spot welding and assembly processes, ensuring the stability and reliability of the overall device.

[0053] In one embodiment, the insulating material of the insulating film layer 5 includes a resin material or a PSA pressure-sensitive adhesive material.

[0054] S104. Perform surface treatment on the flexible substrate 1 and the working coil 4, and spot-weld an auxiliary coil or electronic components on the flexible substrate 1.

[0055] In this step, chemical cleaning or mechanical polishing can be used to clean the flexible substrate 1 and the working coil 4 to avoid residues affecting the welding quality, that is, remove oxides and other impurities on the flexible substrate 1 and the working coil 4, ensure good contact at the welding points, improve the adhesion of the welding material to the flexible substrate 1, reduce the risk of poor welding, and spot-weld an auxiliary coil or electronic components on the flexible substrate 1 to form a reliable electrical connection to meet the application environment requirements of the coil device.

[0056] In one embodiment, the flexible substrate 1 is also connected to electronic components through SMT (Surface Mount Technology), thereby achieving higher circuit integration of the coil device, reducing parasitic inductance and capacitance, and improving electrical performance.

[0057] S105. Set a composite magnetic isolation sheet on the side of the flexible substrate facing away from the working coil, and the composite magnetic isolation sheet is tightly bonded to the flexible substrate through vacuum pressing.

[0058] In this step, by setting the composite magnetic isolation sheet 6, electromagnetic interference of the working coil 4 can be effectively shielded or isolated, improving the electromagnetic compatibility (EMC) of the overall device, and the composite magnetic isolation sheet 6 can help optimize the magnetic field distribution of the working coil 4, effectively reducing magnetic field leakage, improving the energy transmission efficiency of the coil, and enhancing the performance of the coil and the efficiency of the overall system.

[0059] By using the vacuum pressing method, air bubbles, impurities and volatile substances between the composite magnetic isolation sheet 6 and the flexible substrate 1 can be removed, ensuring tight bonding between materials. Through uniform pressure, full contact between the composite magnetic isolation sheet 6 and the flexible substrate 1 is ensured, enhancing the bonding strength and overall reliability.

[0060] In one embodiment, the composite magnetic isolation sheet 6 includes a plurality of first bonding layers 8 and magnetic isolation layers 7 arranged alternately. The plurality of first bonding layers 8 and magnetic isolation layers 7 are tightly bonded to the flexible substrate 1 through vacuum pressing. The first bonding layer 8 connects adjacent magnetic isolation layers 7 and also connects the flexible substrate 1 and the magnetic isolation layer 7.

[0061] Specifically, the magnetic isolation layer 7 may include at least one of nanocrystalline materials, ferrite materials, and wave-absorbing materials. That is, the magnetic isolation layer 7 may be at least one of a nanocrystalline material layer, a ferrite material layer, and a wave-absorbing material layer. It should be noted that nanocrystalline materials have high magnetic permeability and low magnetic loss, can effectively shield electromagnetic interference, and perform well in high-frequency applications. The nanoscale particles meet the material requirements for the thin and lightweight coil device, ensuring the thickness of the composite magnetic isolation sheet 6 and the overall thickness of the coil device. Ferrite materials usually have good chemical stability, good magnetic permeability, and low magnetic loss. Wave-absorbing materials have good electromagnetic wave absorption ability, which can reduce the reflection and interference of electromagnetic waves.

[0062] Among them, the first adhesive layer 8 may include PSA pressure-sensitive adhesive material, which has good self-adhesiveness and flexibility, can adapt to the bending and deformation of the flexible substrate 1, and can maintain stable adhesion without affecting the overall structure.

[0063] Then, several first adhesive layers 8 and the magnetic isolation layer 7 can be tightly adhered to the flexible substrate 1 through vacuum pressing. The specific number of the first adhesive layer 8 and the magnetic isolation layer 7 can be selected according to design requirements or environmental requirements. Under the vacuum pressing method, the bubble, impurities, and volatile substances are removed through uniform pressure for each layer structure, ensuring its tight adhesion to the flexible substrate 1 and simultaneously meeting the ultra-thin requirements of the coil device.

[0064] After the coil device is obtained through the above steps, necessary electrical performance tests and visual inspections can be carried out to ensure product quality.

[0065] In the preparation method of the coil device disclosed in this embodiment, after the flexible substrate 1 is integrally connected to the copper rolling layer 2, the copper rolling layer 2 is die-cut according to a preset circuit pattern, so as to form a multi-strand parallel working coil 4 on the flexible substrate 1, and the working coil 4 is arranged as a planar circuit. After vacuum hot pressing and coating the working coil 4 with an insulating material, an insulating film layer 5 is formed on the working coil 4, and the flexible substrate 1 and the working coil 4 are surface-treated to spot-weld an auxiliary coil or electronic components on the flexible substrate 1. Among them, a composite magnetic isolation sheet 6 is arranged on the side of the flexible substrate 1 facing away from the working coil 4, and the composite magnetic isolation sheet 6 is tightly adhered to the flexible substrate 1 through vacuum pressing. Thus, this embodiment combines die-cutting and vacuum pressing processes to obtain a thin and miniaturized coil device, meeting the performance requirements of high Q value and low resistance, and improving the energy transmission power and preparation cost performance of the coil device.

[0066] It should be noted that under the same performance, the ultra-thin structural design of the coil device in this embodiment is 10-20% thinner than the products of traditional copper winding technology or FPC etching technology, and the preparation cost is 10% lower than that of copper winding technology and 30% lower than that of FPC etching technology.

[0067] In one embodiment, refer toFigure 4 During the surface treatment of the flexible substrate 1 and the working coil 4, as well as the process of spot welding and connecting the auxiliary coil or electronic components on the flexible substrate 1, a differential feed gold finger 9 is provided on the flexible substrate 1. The differential feed gold finger 9 includes a first pad 11 and a second pad 12, and the two ends of the working coil 4 are respectively connected to the first pad 11 and the second pad 12.

[0068] Among them, the first pad 11 and the second pad 12 are designed in parallel and symmetrically to support differential signal transmission. The differential feed gold finger 9 can be connected to the metallized area on the flexible substrate 1 for connecting external circuits or components.

[0069] Furthermore, a first single-sided jumper point 13 is provided at one end of the first pad 11 facing the flexible substrate 1, and a second single-sided jumper point 14 is provided at one end of the second pad 12 facing the flexible substrate 1. The two ends of the working coil 4 are respectively connected to the first single-sided jumper point 13 and the second single-sided jumper point 14; thus ensuring stable signal transmission between the working coil 4 and the differential feed gold finger 9, improving electrical performance, and enabling more flexible adaptation to different circuit configurations and layout requirements through the first single-sided jumper point 13 and the second single-sided jumper point 14, and simplifying the wiring and connection process.

[0070] In one embodiment, refer to Figure 5 The auxiliary coil 10 is wound around the outside of the working coil 4 on the flexible substrate 1; then the working coil 4 and the auxiliary coil 10 can be combined on the flexible substrate 1 to construct a two-in-one antenna device, such as a WPC and NFC two-in-one antenna product. Thus, the WPC coil and the NFC coil are cooperatively configured on the flexible substrate 1, saving the separate antenna stacking space, making the internal space structure stacking of the product more advantageous, saving the manufacturing cost, and improving the material utilization rate.

[0071] Among them, the working coil 4 can include a WPC (Wireless Power Consortium) coil, and the auxiliary coil 10 can include an NFC (Near Field Communication) coil.

[0072] In one embodiment, refer to Figure 5 The differential feed gold finger 9 further includes a third pad 15 and a fourth pad 16, and the two ends of the auxiliary coil 10 are respectively connected to the third pad 15 and the fourth pad 16.

[0073] Among them, the third pad 15 and the fourth pad 16 are designed in parallel and symmetrically to support differential signal transmission. One end of the third pad 15 facing the flexible substrate 1 is provided with a third single-sided jumper point 17, and one end of the fourth pad 16 facing the flexible substrate 1 is provided with a fourth single-sided jumper point 18. Both ends of the auxiliary coil 18 are respectively connected to the third single-sided jumper point 17 and the fourth single-sided jumper point 18, so as to ensure stable signal transmission between the auxiliary coil 10 and the differential feed finger 9, improve electrical performance, and can more flexibly adapt to different circuit configurations and layout requirements through the third single-sided jumper point 17 and the fourth single-sided jumper point 18, and simplify the wiring and connection process.

[0074] Reference Figure 3 、 Figure 4 and Figure 5 , for the coil device of the present application, the preparation method of the coil device of any of the foregoing embodiments can be applied. The coil device includes a flexible substrate 1, a working coil 4, and a composite magnetic isolation sheet 6.

[0075] In the specific implementation process, the working coil 4 is connected to one side of the flexible substrate 1, and the composite magnetic isolation sheet 6 is connected to the other side of the flexible substrate 1.

[0076] Among them, the working coil 4 is arranged as a multi-strand parallel planar circuit to increase the effective copper cross-sectional area of the working coil 4, and thus can meet the requirements of larger energy transmission power and the ultra-thin requirement of the coil device. Under high-frequency conditions, more current can flow through the surfaces of these planar circuits, maximizing the effective utilization rate of the conductor, thereby reducing the increase in resistance caused by the skin effect. The working coil 4 can be die-cut and processed according to a preset circuit pattern. For the specific die-cutting process, reference can be made to the description of the preparation method of the coil device in the present application above, and details will not be elaborated here.

[0077] The composite magnetic isolation sheet 6 of this embodiment is vacuum-pressed on the other side of the flexible substrate 1, so as to ensure the tight fit between the composite magnetic isolation sheet 6 and the flexible substrate 1.

[0078] It should be noted that the composite magnetic isolation sheet 6 may include a plurality of alternately arranged first adhesive layers 8 and magnetic isolation layers 7. The plurality of first adhesive layers 8 and magnetic isolation layers 7 are tightly adhered to the flexible substrate 1 through vacuum pressing. The first adhesive layer 8 connects adjacent magnetic isolation layers 7 and also connects the flexible substrate 1 and the magnetic isolation layer 7.

[0079] Furthermore, the magnetic isolation layer 7 may include at least one of nanocrystalline materials, ferrite materials, and wave-absorbing materials, that is, the magnetic isolation layer 7 may be at least one of a nanocrystalline material layer, a ferrite material layer, and a wave-absorbing material layer. Among them, the first adhesive layer 8 may include PSA pressure-sensitive adhesive materials.

[0080] Then, a plurality of first adhesive layers 8 and magnetic isolation layers 7 can be tightly adhered to the flexible substrate 1 through vacuum pressing. The specific numbers of the first adhesive layers 8 and magnetic isolation layers 7 can be selected according to design requirements or environmental requirements. Under the vacuum pressing means, bubbles, impurities, and volatile substances are removed through uniform pressure for each layer structure, ensuring its tight adhesion to the flexible substrate 1, and at the same time meeting the ultra-thin requirement of the coil device.

[0081] In the specific implementation process, the working coil 4 includes multiple strands of parallel turns, and there is the same set row interval K between each turn, ensuring uniform current distribution between each turn, reducing performance problems caused by electromagnetic interference between turns, and also improving design flexibility, enabling the working coil 4 to adapt to different electrical and mechanical requirements in various application scenarios.

[0082] In one embodiment, the set row interval K≥10um to optimize current transmission, reduce interference, and optimize the volume of the coil device while ensuring the performance of the working coil 4.

[0083] Wherein, both the side of the working coil 4 facing the flexible substrate 1 and the side facing away from the flexible substrate 1 are planes, thereby constructing a multi-strand parallel planar circuit design.

[0084] Wherein, an insulating film layer 5 is connected to the side of the working coil 4 facing away from the flexible substrate 1, thereby effectively preventing electrical short circuits between the turns of the working coil 4 and between the working coil 4 and other circuit components, protecting the coil device from external electrical interference, and improving the overall electrical safety of the device.

[0085] In one embodiment, the flexible substrate 1 includes a polyimide PI material or a polyester PET film material.

[0086] In the specific implementation process, the flexible substrate 1 is further provided with an auxiliary coil 10. The auxiliary coil 10 is wound around the outside of the working coil 4 on the flexible substrate 1. Then, the combination of the working coil 4 and the auxiliary coil 10 on the flexible substrate 1 can construct a two-in-one antenna device, which can make the internal space structure stacking of the product more advantageous, thereby saving the manufacturing cost and improving the material utilization rate.

[0087] Furthermore, a differential feed gold finger 9 is provided on the flexible substrate 1. The differential feed gold finger 9 includes a first pad 11 and a second pad 12. The two ends of the working coil 4 are respectively connected to the first pad 11 and the second pad 12.

[0088] Among them, one end of the first pad 11 facing the flexible substrate 1 is provided with a first single-sided jumper point 13, one end of the second pad 12 facing the flexible substrate 1 is provided with a second single-sided jumper point 14, and two ends of the working coil 4 are respectively connected to the first single-sided jumper point 13 and the second single-sided jumper point 14, so as to ensure stable signal transmission between the working coil 4 and the differential feeding gold finger 9, improve electrical performance, and can more flexibly adapt to different circuit configurations and layout requirements through the first single-sided jumper point 13 and the second single-sided jumper point 14, and simplify the wiring and connection process.

[0089] Furthermore, the differential feeding gold finger 9 further includes a third pad 15 and a fourth pad 16, and two ends of the auxiliary coil 10 are respectively connected to the third pad 15 and the fourth pad 16.

[0090] Among them, one end of the third pad 15 facing the flexible substrate 1 is provided with a third single-sided jumper point 17, one end of the fourth pad 16 facing the flexible substrate 1 is provided with a fourth single-sided jumper point 18, and two ends of the auxiliary coil 18 are respectively connected to the third single-sided jumper point 17 and the fourth single-sided jumper point 18.

[0091] It should be noted that the flexible substrate 1, the working coil 4, and the auxiliary coil 10 can all be wrapped by a packaging composite layer with a set dielectric constant, and the packaging composite layer can be composed of a composite material with adhesiveness, so as to provide safety protection for the coil device.

[0092] In one embodiment, the overall thickness of the coil device ≥ 0.17 mm, that is, through the above settings, the overall thickness of the coil device can reach 0.17 mm, so as to achieve the purpose of miniaturization and thinning of the coil device.

[0093] In one embodiment, the working coil 4 can include a WPC coil, and the auxiliary coil 10 can include an NFC coil.

[0094] Referring to Table 1, which are the performance parameters of the coil device in the embodiment of the present application. It can be seen that the coil device in the embodiment of the present application meets the requirements of high Q value (quality factor) and low resistance. That is, under the same performance requirements, the ultra-thin structural design of the coil device in this embodiment is 10-20% thinner than the products of traditional copper winding technology or FPC etching technology; the manufacturing cost is 10% lower than that of copper winding technology and 30% lower than that of FPC etching technology.

[0095]

[0096] Table 1

[0097] In the coil device of the present application, the flexible substrate 1 is respectively connected to a composite magnetic isolation sheet 6 and a working coil 4 formed by die-cutting according to a preset circuit pattern. The working coil 4 is arranged in a planar circuit with multiple strands connected in parallel, and the side facing the flexible substrate 1 and the side away from the flexible substrate 1 are both flat. The composite magnetic isolation sheet 6 includes a plurality of alternatingly arranged first adhesive layers 8 and magnetic isolation layers 7. The plurality of first adhesive layers 8 and magnetic isolation layers 7 are vacuum pressed on the flexible substrate 1. Thus, combined with die-cutting and vacuum pressing, a thin and miniaturized coil device is obtained, which meets the performance requirements of high Q value and low resistance, and improves the energy transmission power and preparation cost-effectiveness of the coil device.

[0098] The above is a detailed introduction to the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the core idea of the present application. At the same time, for technical personnel in this field, according to the idea of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A coil device, characterized in that, It comprises a flexible substrate, one side of which is connected to a working coil formed by die-cutting according to a preset circuit pattern, the other side of which is connected to a composite magnetic isolation sheet, the working coil is arranged in a planar circuit with multiple strands connected in parallel, the side of the working coil facing the flexible substrate and the side away from the flexible substrate are both planes, and the side away from the flexible substrate is connected to an insulating film layer, the composite magnetic isolation sheet comprises a plurality of alternately arranged first adhesive layers and magnetic isolation layers, a plurality of the first adhesive layers and the magnetic isolation layers are vacuum pressed on the flexible substrate, the first adhesive layer connects adjacent magnetic isolation layers, and connects the flexible substrate and the magnetic isolation layer.

2. The coil device according to claim 1, wherein The working coil includes a plurality of parallel-connected wire turns, each of which has the same set row spacing, and the set row spacing is ≥10 um.

3. The coil device according to claim 1, wherein The first adhesive layer includes a PSA pressure-sensitive adhesive material layer, and the magnetic isolation layer includes at least one of a nanocrystalline material layer, a ferrite material layer, and a wave-absorbing material layer.

4. The coil device according to claim 1, characterized in that, The flexible substrate is further provided with an auxiliary coil, and the auxiliary coil is wound on the flexible substrate outside the working coil.

5. The coil device according to claim 1, characterized in that The flexible substrate includes polyimide PI material or polyester PET film material.

6. The coil device according to claim 4, wherein, A differential feeding gold finger is arranged on the flexible substrate, and the differential feeding gold finger comprises a first pad and a second pad, and two ends of the working coil are connected to the first pad and the second pad respectively.

7. The coil device according to claim 6, characterized in that, A first single-sided jumper point is disposed at one end of the first pad facing the flexible substrate, a second single-sided jumper point is disposed at one end of the second pad facing the flexible substrate, and two ends of the working coil are connected to the first single-sided jumper point and the second single-sided jumper point respectively.

8. The coil device according to claim 6, wherein The differential feeding gold finger includes a third pad and a fourth pad, and two ends of the auxiliary coil are connected to the third pad and the fourth pad respectively.

9. The coil device according to claim 8, wherein, The third pad has a third single-sided jumper point at one end facing the flexible substrate, the fourth pad has a fourth single-sided jumper point at one end facing the flexible substrate, and both ends of the auxiliary coil are connected to the third single-sided jumper point and the fourth single-sided jumper point respectively.

10. The coil device according to claim 4, characterized in that, The working coil includes a WPC coil, and the auxiliary coil includes an NFC coil; the flexible substrate, the working coil, and the auxiliary coil are all wrapped by a packaging composite layer with a set dielectric constant, and the overall thickness of the coil device is ≥0.17 mm.

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