Flexible planar inductive coil suitable for embedding in a product

Abstract

The present disclosure provides at least apparatuses, systems, and methods for providing flexible planar inductive coils that can be embedded in products, for example. The apparatuses, systems, and methods can include at least one conformable substrate and a matched functional ink set printed onto at least one substantially planar surface of the at least one conformable substrate. The printing can form at least one layer of additive conductive traces capable of receiving electrical current from at least one power source and layered around a central axis within the plane of the at least one conformable substrate into continuous conductive traces.

Description

[0001] This application is a divisional application of Chinese patent application No. 201880038536.9, filed on May 17, 2018, entitled "Apparatus, System and Method for Producing Planar Coils".

[0002] Cross-reference to related applications

[0003] This application claims priority to U.S. Application No. 15 / 598044, filed May 17, 2017, entitled “Apparatus, System, and Method for Producing Planar Coils,” the entire contents of which are incorporated herein by reference. Technical Field

[0004] This disclosure generally relates to additive electronic devices, and more specifically, to the production of planar coils. Background Technology

[0005] Printed electronics manufactures electronic (and other) devices on a variety of substrates using printing or "additive" methods. Printing typically defines patterns on various substrates, such as using screen printing, flexographic printing, gravure printing, offset printing, and inkjet printing. Electrically functional electronic or optical inks are deposited onto the substrate using one or more of these printing techniques to create active or passive devices such as transistors, capacitors, and resistors.

[0006] Printed electronic devices can use inorganic or organic inks. These ink materials can be deposited using solution methods, vacuum methods, or other methods. Ink layers can be applied one after another. Features of printed electronic devices can be or include semiconductors, metallic or non-metallic conductors, nanoparticles, nanotubes, etc.

[0007] Rigid substrates such as glass and silicon can be used for printed electronics. Polyethylene terephthalate foil (PET) is a common substrate, partly due to its low cost and moderate high-temperature stability. Polyethylene naphthalate (PEN), polyimide (PI) foil (PI), polycarbonate (PC), and thermoplastic polyurethane (TPU) are examples of alternative substrates. Alternative substrates also include paper and textiles, although the high surface roughness and high absorbency of such substrates can pose problems for printing electronics on them. In short, typically, a suitable substrate for printed electronics preferably has minimal roughness, suitable wettability, and low absorbency.

[0008] Printed electronics offer the advantages of low-cost, high-volume manufacturing. The lower cost allows for use in many applications, but often results in reduced performance compared to "conventional electronics." Furthermore, manufacturing methods on a wide variety of substrates allow for the use of electronics in ways previously unknown, without significantly increasing costs. For example, printing on flexible substrates allows electronics to be placed on curved surfaces, eliminating the significant expense associated with using conventional electronics in such cases.

[0009] Furthermore, conventional electronics typically have greater limitations in feature size than supplemental electronics. That is, printed electronics can be used to provide higher resolution and smaller structures, thereby providing variability in circuit density, precision layering, and functionality not available with conventional electronics.

[0010] In printed electronics, control of thickness, aperture, and material compatibility is essential. In practice, the choice of printing method can be determined by requirements related to the printed layers, layer characteristics, and the performance of the printed materials, such as the aforementioned thickness, aperture, and material type, as well as by economic and technical considerations of the final printed product.

[0011] Generally, film-based inkjet and screen printing are best suited for small-batch, high-precision printed electronic devices. Gravure, offset, and flexographic printing are more common in high-volume production. Offset and flexographic printing are typically used for inorganic and organic conductors as well as dielectrics, while gravure printing is well-suited for quality-sensitive layers, such as those within transistors, due to the high-quality layers it provides.

[0012] Inkjet printers are very versatile, but due to the potential for nozzle clogging, they typically offer lower throughput and are better suited for low-viscosity soluble materials. Screen printing is often used to produce patterned, thick layers from paste-like materials. Aerosol jet printing atomizes the ink and uses an airflow to gather the printed droplets into a tightly aligned bundle.

[0013] Evaporation printing combines high-precision screen printing with material evaporation. Material is deposited through a high-precision template that is "aligned" onto the substrate. Other printing methods can also be used, such as microcontact printing and photolithography, such as nanoimprint lithography.

[0014] The functionality and printability of electronic devices can be mutually exclusive, requiring optimization to achieve the best results. For example, a higher molecular weight in a polymer increases conductivity but reduces solubility. Furthermore, viscosity, surface tension, and solids content must be carefully selected and strictly controlled during printing. Interlayer interactions, as well as post-deposition processes and layers, also affect the properties of the final product.

[0015] Printed electronics can provide patterns with widths ranging from 0.03 to 10 mm or less, and layer thicknesses from tens of nanometers to greater than 10 μm. Once printing and patterning are complete, post-processing of the substrate may be required to achieve the final electrical and mechanical properties. Specific ink and substrate combinations can further advance post-processing.

[0016] In known technologies, one type of electronic component manufactured using the aforementioned conventional electronic techniques is the induction coil for various applications. Conventional processes for forming induction coils for these applications involve high-vacuum, high-temperature deposition processes and require complex photolithographic patterning techniques. Therefore, these techniques historically used for producing induction coils have often resulted in manufacturing defects such as low yields, high resource requirements (e.g., higher manufacturing temperatures), and consequently, significantly more complex and resource-intensive manufacturing processes, all of which lead to unnecessarily high production costs and low output.

[0017] Those skilled in the art will understand that insufficient investment of dedicated processing resources required to properly manufacture induction coils using specialized techniques, and consequently, the inability to meet high processing costs, can lead to deficiencies that adversely affect the capacitive performance of the coils thus formed. For example, in acoustic implementations, inadequate coil formation can result in acoustic distortion, leading to unpleasant sound.

[0018] Therefore, there is a need for an apparatus, system, and method for forming induction coils for various applications using a high-capacity, low-cost approach. Summary of the Invention

[0019] This disclosure may at least provide apparatus, systems, and methods for providing (e.g., for embedding in a product) flexible planar induction coils. The apparatus, systems, and methods may include at least one conformal substrate and a matching functional ink set, which is printed onto at least one substantially flat surface of the at least one conformal substrate. This printing may form at least one layer of additive conductive traces capable of receiving current from at least one power source, and layered as continuous conductive traces around a central axis in the plane of the at least one conformal substrate.

[0020] For example, continuous conductive traces can be designed to be rectangular, circular, or elliptical. As a non-limiting example, a flexible planar induction coil can be an acoustic, antenna, or inductively coupled coil.

[0021] The coil may include at least one through-hole at least partially filled with a conductor. The coil may include at least one second layer of second additive conductive traces, which are capable of receiving current from the at least one layer of additive conductive traces, for example through the through-holes, and are layered into continuous second conductive traces around a second central axis.

[0022] As a non-limiting example, at least one flexible substrate may be formed of plastic, glass, polymer, paper, or textiles. The conductive traces may be conductive traces, for example, screen-printed, gravure-printed, flexographic-printed, inkjet-printed, or aerosol-jet-printed.

[0023] Continuous conductive traces can be high-density. As a non-limiting example, high density can provide series resistance in the range of 32 ohms to 250 ohms. High density can provide linewidths, for example, in the range of 180 μm to 260 μm. For instance, some inks in a matching ink group can have a volume factor between 3 and 15.

[0024] Therefore, this disclosure provides an apparatus, system, and method for forming induction coils for various applications using a high-capacity, low-cost approach. Attached Figure Description

[0025] Exemplary apparatuses, systems, and methods will be described below with reference to the accompanying drawings, which are given by way of non-limiting example only, wherein:

[0026] Figure 1 This is a schematic diagram of some embodiments of printed planar conductive coils;

[0027] Figure 2 This is a schematic diagram of some embodiments of printed planar conductive coils;

[0028] Figure 3 This is a schematic diagram of some implementations of printing screens;

[0029] Figure 4 This is a schematic diagram of an exemplary planar induction coil;

[0030] Figure 5 This is a schematic diagram of some embodiments of a planar conductive coil;

[0031] Figure 6 This is a schematic diagram of an exemplary through-hole formation for conductively connecting multiple planar induction coils; and

[0032] Figure 7 This is a flowchart of an exemplary method for additively processing a planar induction coil. Detailed Implementation

[0033] The accompanying drawings and descriptions provided herein are simplified to illustrate aspects relevant to a clear understanding of the apparatuses, systems, and methods described herein, while other aspects that may be found in typical similar apparatuses, systems, and methods are omitted for clarity. Those skilled in the art will therefore recognize that other elements and / or operations may be desirable and / or necessary for implementing the apparatuses, systems, and methods described herein. However, because such elements and operations are known in the art and because they are not conducive to a better understanding of this disclosure, a discussion of such elements and operations may not be provided herein for the sake of brevity. Nevertheless, this disclosure is still considered to include all such elements, variations, and modifications of the described aspects that are known to those skilled in the art.

[0034] Various embodiments are provided throughout this disclosure to make it thorough and complete, and to fully convey the scope of the disclosed embodiments to those skilled in the art. Numerous specific details, such as examples of particular components, apparatuses, and methods, are set forth to provide a thorough understanding of embodiments of the invention. However, it will be apparent to those skilled in the art that certain specific details disclosed are not necessary, and that embodiments may be embodied in different forms. Therefore, the disclosed embodiments should not be construed as limiting the scope of this disclosure. As mentioned above, in some embodiments, well-known processes, well-known apparatus structures, and well-known techniques may not be described in detail.

[0035] The terminology used herein is for the purpose of describing particular implementations only and should not be construed as limiting. For example, the singular forms “a,” “an,” and “described” as used herein may also be intended to include the plural forms unless the context clearly indicates otherwise. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of the illustrated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. The steps, processes, and operations described herein should not be construed as necessarily interpreting their respective performance in the specific order discussed or shown, unless explicitly identified as a preferred or desired performance order. It should also be understood that additional or alternative steps may be used in place of or in combination with the disclosed aspects.

[0036] When a component or layer is referred to as “on,” “above,” “connected to,” or “coupled to” another component or layer, unless otherwise expressly stated, it may be directly on, directly connected to, or coupled to the other component or layer, or there may be intermediate components or layers. Conversely, if a component is stated as “directly on,” “directly connected to,” or “directly coupled to” another component or layer, it indicates that there are no intermediate components or layers. Other terms used to describe relationships between components should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). Furthermore, as used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0037] Furthermore, while the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, or portion from another. Unless explicitly stated in the context, terms such as “first,” “second,” and other numerical terms used herein do not imply order or sequence. Therefore, without departing from the teachings of the embodiments, the first element, component, region, layer, or portion discussed below may be referred to as the second element, component, region, layer, or portion.

[0038] Historically, and as discussed throughout this text, the formation of many small aspects of devices or miniature devices has typically integrated deposition and etching processes. That is, traces that form device features such as waveguides, vias, connectors, etc. (e.g., conductive traces, dielectric traces, insulating traces, etc.) are usually formed by subtractive processes, i.e., layers are created, and then etched away to remove portions of those layers to form the desired topology and features of the device.

[0039] Additive manufacturing processes have been developed to additively form device features and aspects, that is, to form device features and aspects by “printing” desired features in desired locations and shapes. This allows many devices and device elements previously formed using subtractive, or “conventional” processes to be formed via additive processes instead. Such device elements include, but are not limited to, printed transistors, carbon-resistant heating elements, piezoelectric elements and audio elements, photodetectors and transmitters, and medical devices.

[0040] In short, the printing of such devices and components depends on many factors, including the compatibility of the deposition material, such as ink, with the receiving substrate for a specific application. This ability to use a variety of substrates can provide unique properties for previously unknown additive processing devices in etching equipment, such as the tensile and bending capabilities of the created devices, and / or the ability to operate in previously unknown or harsh environments. As a non-limiting example, the ability to print electronic traces on plasticized substrates allows those substrates to be conformed after printing has occurred. Thus, for example, device screens and similar interactive devices are created and formed into devices into which interactive elements will be integrated, after device fabrication rather than during device fabrication.

[0041] However, known additive manufacturing methods do have limitations compared to the performance achievable using subtractive methods. For example, conductive traces formed using additive manufacturing typically have more limited conductivity compared to conductive traces formed using subtractive methods. This is partly because it is not currently possible to print pure copper traces provided by subtractive methods using modern additive manufacturing techniques. Therefore, some devices and components can be substantially modified to accommodate the improved characteristics obtained by using printed traces in additive manufacturing, compared to conventional electronic device fabrication techniques.

[0042] In implementation, a multitude of factors must be balanced for each unique application in order to optimally obtain properties that are as close as possible to those previously available only in subtractive methods. For example, in the disclosed apparatus and methods for creating planar induction coils for various applications, compatibility must be evaluated among the substrate for a given application and its acceptability, the ink used and its conductivity, the fineness of the printed traces used, the spacing, density and consistency of the printed ink, the type of printing performed (i.e., screen printing versus other types of printing), the thickness of the printed layer, the chemical reactivity of the substrate and the ink, etc.

[0043] Furthermore, since a variety of inks can be used to produce the disclosed coil elements, the compatibility of the inks used with each other is also an aspect of the implementation. For example, for all inks within a given ink group, the chemical reactions between inks, the different curing methods between inks, and the deposition methods between inks must be evaluated. It is also worth noting that, based on the discussion herein, those skilled in the art will understand that different inks within an ink group can have variable properties after deposition. For example, some inks may experience a trough effect at the center of the deposition trace of that ink, while after deposition, using that ink produces a peak on the outside of the trace. Therefore, since the thickness of the trace deposited using such inks can mitigate or enhance the aforementioned effects, attention can be paid to the manner and consistency of application of each ink within the ink group in the implementation.

[0044] The balance of the aforementioned effects allows for the use of printed electronics in previously unknown environments to produce the disclosed planar induction coils for a variety of applications. Furthermore, the suitability of printed electronics for use with flexible substrates and substrates with non-uniform topology allows for the integration of printed electronics as part of a product without the need for mechanical integration of the electronics into the final product. Needless to say, this can include printing electronics onto substrates unsuitable for creating electronics using subtractive methods, such as fabrics, plastics and other substrates that do not provide a “sticky” surface, organic substrates, etc. This may occur, for example, because additive manufacturing allows for the use of different printing types within each subsequent printed layer of the printed device; thus, the functionality (e.g., mechanical, electrical, structural, or other) provided by each layer can vary between printed layers throughout the deposition process. Additionally, other methods, such as laser selective printing, can be employed in conjunction with or after additive manufacturing.

[0045] Additive processing can be used to provide various solutions for balancing the aforementioned factors. For example, flexible substrates can be provided, with printing on one or both sides of the substrate. This multi-sided printing can allow overcoming some of the drawbacks of additive manufacturing. This and other disclosed methods of overcoming the problems in additive manufacturing can allow the printing of flexible planar induction coils on flexible substrates, for example, for acoustic, wireless power, and antenna applications, which can at least partially overcome the disadvantages of using conventional electronic device processes to provide such induction coils.

[0046] More specifically, planar inductors for various applications have historically been manufactured using subtractive, conventional methods in known technologies. These processes, including slot die and C-MOS processes, involve high-vacuum, high-temperature deposition and require sophisticated photolithographic patterning techniques. Therefore, using additive manufacturing to produce these planar inductors offers many advantages over known technologies, such as increased throughput, reduced processing resource usage, lower manufacturing temperatures, and consequently, significantly reduced complexity and resource-intensive manufacturing processes.

[0047] Those skilled in the art will understand that, for example, deficiencies in a planar induction coil can have detrimental effects on performance, as is evident in acoustic applications. For instance, harmonics and acoustic distortion in acoustic implementations can result in poor sound. Similarly, insufficient stiffness of the diaphragm can lead to poor sound, while excessive stiffness can result in no sound being produced. These problems are also addressed in the disclosed embodiments.

[0048] By way of non-limiting example and by reference throughout, the disclosed techniques can allow traces to be generated on one or both sides of a substrate to form, for example, multifaceted, series, or parallel reference planar inductor coils. In this case, one or more vias can be formed between the sides of the substrate to generate series or parallel coils on opposite sides of the substrate, which can then be connected through the substrate.

[0049] The aforementioned and other advantages stem from the ability to directly print planar induction coils onto a variety of substrates, including those using known additive printing techniques on mechanically flexible substrates such as plastics, paper, and textiles, thereby increasing the versatility of the planar induction coils. As non-limiting examples, such applications could include planar coils used in NFC or RFID antennas (e.g., for smart packaging), planar speaker diaphragms in acoustic applications, and inductive couplers (e.g., for use in wireless power transmission).

[0050] like Figure 1 As shown in the embodiments and according to the disclosed methods, at least one conductive ink 102 from ink group 104, such as silver, gold, aluminum, copper and / or organic conductors, is printed on a substrate 106 (e.g., glass, plastic, polymer and / or fabric substrate) using known additive manufacturing processes (e.g., screen printing, gravure printing, flexographic printing, inkjet printing and / or aerosol jet printing) to form a planar rectangular or spiral coil 110. It is noteworthy that after the ink 104 is deposited and the trace 110a is thus formed, a secondary processing, such as drying or curing, may be required to achieve an active conductive trace.

[0051] Thus, a planar induction coil 110 can be created, which can receive / transmit from / to a feed / source 109, and / or can be coupled to other coils using conductive and / or inductive processes. Additionally, and depending on the substrate 106 used, the planar coil 110 can be surrounded or integrated onto virtually any surface required or used for such an induction coil 110. As used herein, "planar" may mean that the disclosed coils are produced substantially on a single plane, i.e., one or more induction coils are printed on a single sheet substrate using additive manufacturing; this may mean that the magnetic properties provided by such coils appear along a uniform plane, i.e., embodiments provide diaphragms formed as planes within opposing magnetic fields.

[0052] To provide a “planar” coil without using subtractive methods that still meet the required performance characteristics (e.g., those in acoustic embodiments) in known techniques, a balance must be maintained between several factors of ink group 104 and the printing technique used, as described above. For example, the traces should be thick enough to provide sufficient conductivity, but increased trace thickness can be affected by quality inhomogeneity. On the other hand, fine traces may be particularly needed in acoustic embodiments because this allows for an increase in the number of traces in magnetic field formation, resulting in improved acoustic sound. However, increased line density increases the demand for printing detail for each particular trace, and more wires within the coil increase the resistivity of the system. That is, in known techniques, high-quality sound is produced due to the increased conductivity of bulk metal traces generated using subtractive methods; however, in the disclosed embodiments, to improve magnetic field efficiency, increased line density must be used, thus using traces with lower conductivity but higher line density to improve the provided sound. However, for diaphragms produced using additive methods, this increased line density requires finer wires and more refined processes for better control of resistivity. In other words, using known techniques to optimize conductivity to generate competitive sounds also requires optimizing resistivity, because resistivity increases with increasing linear density (which has adverse effects).

[0053] Additive processing can be used to provide various solutions for balancing the aforementioned factors. For example, a thin substrate 106 can be provided, wherein printing can be performed on both sides 106a, 106b of the substrate 106 to create coil traces 104a on both sides 106a, 106b of the substrate 106, such as... Figure 2 As shown. Subsequently, vias 202, i.e., holes, can be formed between the sides 106a and 106b of the thin substrate, thereby allowing multiple adjacent coils to be generated on both sides of the substrate, for example, via conductive connections through the vias 202, which can be connected through the substrate. This allows for the provision of parallel or series circuits using additive manufacturing. It will be apparent to those skilled in the art that such parallel or series circuits may not be readily available in the prior art.

[0054] The aforementioned characteristics are applicable not only to acoustic applications but also, as described above, to any inductively coupled application, such as antenna applications. In each such application, inductance and series resistance are critical performance factors, and the planar nature of the embodiments described herein, combined with the series or parallel nature of some embodiments, allows for a balance of characteristics to achieve at least substantially optimal performance. In short, as a non-limiting example, the series resistance provided by the embodiments can range from 32 ohms to 250 ohms, thereby allowing, for example, acceptable acoustic performance.

[0055] Various material properties provide for the disclosed performance levels. For example, embodiments may require inks with high conductivity, and thus the resulting conductive traces 104a may have more bulky properties. However, inks with high conductivity typically tend to have high flowability and low viscosity. Thus, and because, as mentioned above, trace fineness is critical in higher-density coils, the inks used in the embodiments herein may have sufficiently low conductivity to have sufficiently high viscosity so as not to bridge across the traces 110a of the coil diaphragm, which would adversely create short circuits in electric and magnetic fields. Therefore, as a non-limiting example, the inks used to form the traces discussed herein may have a volume factor between 3 and 15. Furthermore, standard printing alignment and techniques for inks with such volume factors can be combined with the embodiments. Moreover, in some embodiments, additional additive printing techniques, such as centering and protection, dielectric and / or insulating layers, may be employed to form the planar induction coil 110 or aspects thereof.

[0056] More specifically, and as a non-limiting example, conductive inks, such as Henkel 479SS, can be used to form coil 110. Furthermore, other additive processing materials, such as conductive epoxy resins, such as Ablestic ABP2031S, can be used to create vias between two different conductive layers. Dielectric inks can be used to insulate conductive traces from other conductive layers or any other layers, for example, through chemical and / or electrical insulation. Moreover, such inks, conductive epoxy resins, and other components allow certain embodiments to be applied to particularly thin substrates, such as substrates with a thickness ranging from 10 μm to 10 mm, for example, a 0.25 mm substrate. One such available exemplary substrate is DuPont's Melenex ST510PET.

[0057] Figure 3 A screen 240 is shown, which can provide a printing screen suitable for printing planar induction coils 110 using additive manufacturing. The screen 240 may, for example, include linewidths 242 of 180 μm, 220 μm, 260 μm, etc., and / or gaps 244. Moreover, known alignment techniques can be employed to properly align the screen printing, including double-sided printing alignment techniques. For example, known techniques can be used to create through-holes between coils using the screen 240 or other printing methods, and / or to cut the printed coils to preferred design dimensions. Table 1 below provides various exemplary screen specifications, for example, that can be used for the screen 240.

[0058]

[0059] Table 1

[0060] Figure 4An exemplary planar induction coil 260 fabricated on the top side 266 of an exemplary substrate 270 is shown. Table 2 below illustrates examples such as... Figure 4 The average dimensions of the printed line width and gap in the exemplary implementation.

[0061]

[0062] Table 2

[0063] Figure 5 This is an enlarged illustration of the effective line density 302 of the trace 104a that can be produced in some embodiments. As cited herein, the performance provided by the enhanced line density 302 can be further improved by using printing on both sides of the substrate, for example by using vias extending between the top and bottom printed coils.

[0064] Figure 6 An exemplary via 310 is shown for conductively connecting traces 104a of a plurality of planar induction coils. In this example, as shown in steps (a) and (b), a via 312, for example, a via in the range of 0.005-0.05 inches (or more particularly 0.005 inches), is cut into the trace 104a of at least one coil. Conductive ink 316 can then be applied to connect the top-side trace 104a and the bottom-side coil trace 322 through the via 310. This application can be unilateral or can be performed on both sides, for example, sequentially or simultaneously. As shown in step (c), the connected via 310 filled with conductive ink conductively mates the top trace 104a and the bottom coil trace 322.

[0065] Figure 7 This is a flowchart illustrating an exemplary method 800 for providing an additively processed planar induction coil. In step 802, ink sets are matched to each other for printing compatible ink layers within the ink sets and matched to a receiving substrate for the planar induction coil. In step 804, a conductive layer formed from at least one ink from the ink sets is additionally deposited on the substrate at a desired density.

[0066] In step 806, the additional deposited layer is cured. In step 808, a second ink may be deposited to connect the plurality of planar conductive coils printed in step 804 through one or more vias. In step 810, these connecting ink deposits may be cured as needed.

[0067] Furthermore, this disclosure is provided so that any person skilled in the art can implement or use the disclosed embodiments. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. A flexible planar induction coil suitable for embedding in products, comprising: At least one flexible substrate; Matching functional ink set, which includes matching functional inks for additive printing, and is at least matched to: The acceptability of the flexible substrate, the flexible substrate being printed with the matching functional ink; and, Chemical reactivity between the substrate and the matching functional ink; The matching functional ink group is continuously printed onto multiple continuous additive printing layers to form: At least one of the plurality of continuous additive printing layers is located on top of the substrate and in a plane parallel to the substrate, and includes conductive traces capable of receiving current from at least one power source; The concentric, continuous conductive traces have alternating linewidths and line gaps, and are arranged around a central axis of a plane passing through the at least one flexible substrate, wherein the linewidths are in the range of 180 μm to 260 μm.

2. The flexible planar induction coil according to claim 1, wherein the continuous conductive traces are at least one of circular and elliptical shapes.

3. The flexible planar induction coil according to claim 1, wherein the flexible planar induction coil includes an acoustic coil.

4. The flexible planar induction coil according to claim 1, wherein the flexible planar induction coil includes an antenna coil.

5. The flexible planar induction coil according to claim 1 further includes at least one through-hole at least partially filled with a conductive filler.

6. The flexible planar induction coil according to claim 5 further includes at least one second additive conductive trace in a second layer, the second additive conductive trace being capable of receiving current from the conductive trace through the at least one through-hole, and being layered into continuous second conductive traces around a second central axis.

7. The flexible planar induction coil of claim 6, wherein the second additive conductive trace of the at least one second layer lies in the plane of the at least one flexible substrate and on the opposite surface of the at least one flexible substrate.

8. The flexible planar induction coil of claim 6, further comprising a second of the at least one flexible substrate, wherein the second additive conductive trace of the at least one second layer lies in the plane of the second of the at least one flexible substrate.

9. The flexible planar induction coil according to claim 8, wherein the central axis and the second central axis are substantially aligned.

10. The flexible planar induction coil of claim 8, wherein the at least one layer and the at least one second layer comprise one of series and parallel connections of the planar induction coils.

11. The flexible planar induction coil of claim 7, wherein the at least one through-hole is substantially outside the continuous conductive trace.

12. The flexible planar induction coil according to claim 1, wherein the matching functional ink group comprises at least one of silver, gold, aluminum, copper and organic conductive ink.

13. The flexible planar induction coil according to claim 1, wherein the conductive trace includes one of screen-printed conductive trace, gravure-printed conductive trace, flexographic-printed conductive trace, inkjet-printed conductive trace, and aerosol jet-printed conductive trace.

14. The flexible planar induction coil according to claim 1, wherein the conductive trace comprises a solidified conductive trace.

15. The flexible planar induction coil according to claim 1, wherein the planar induction coil is inductively coupled to at least one secondary induction coil.

16. The flexible planar induction coil according to claim 1, wherein the planar plane includes a magnetic plane.

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