Coil

Abstract

A coil is disclosed. The coil includes a multilayer film wound to form a plurality of substantially concentric loops and substantially planar opposing first and second major surfaces of the coil. The multilayer film includes at least one electrically conductive first layer. The multilayer film further includes an elastically deformable adhesive second layer substantially co-extensive with the at least one electrically conductive first layer in length along a winding direction of the coil and in width generally along a thickness direction of the coil. The elastically deformable adhesive second layer bonds adjacent loops to each other. The elastically deformable adhesive second layer is configured to elastically deform to at least change relative positions of at least some of the adjacent loops while maintaining the bonding between the adjacent loops.

Description

[0001] COIL

[0002] Technical Field

[0003] The present disclosure relates generally to a coil including a multilayer film, and more specifically, to an elastically deformable electrically conductive coil.

[0004] Background

[0005] Inductors or coils may be used in power electronics, especially in power conversion circuits, such as AC-DC converters, DC-DC converters, and the like, as well as in electromagnetic interference (EMI) filters, such as common mode noise filters and differential mode noise filters. Use of a variableinductance coil in the power conversion circuits may reduce current ripple and may consequently improve a power conversion efficiency of the power conversion circuits.

[0006] Furthermore, coils may be used for magnetic resonance imaging (MRI) of small objects. However, use of a planar coil in the MRI may cause difficulties in obtaining deep images of three- dimensional objects. A three-dimensional shaped coil may provide higher resolution MRI images of the three dimensional objects as compared to the planar coil.

[0007] Summary

[0008] In a first aspect, the present disclosure provides a coil. The coil includes a multilayer film wound to form a plurality of substantially concentric loops and substantially planar opposing first and second major surfaces of the coil. The multilayer film includes at least one electrically conductive first layer. The multilayer film further includes an elastically deformable adhesive second layer substantially co-extensive with the at least one electrically conductive first layer in length along a winding direction of the coil and in width generally along a thickness direction of the coil. The elastically deformable adhesive second layer bonds adjacent loops to each other. The elastically deformable adhesive second layer is configured to elastically deform to at least change relative positions of at least some of the adjacent loops while maintaining the bonding between the adjacent loops.

[0009] In a second aspect, the present disclosure provides an elastically deformable electrically conductive coil. The elastically deformable electrically conductive coil includes a plurality of electrically connected electrically conductive loops. The elastically deformable electrically conductive coil is elastically deformable between at least first and second coil configurations in which a same dimension of the elastically deformable electrically conductive coil elastically changes by at least 20%. In each of the first and second coil configurations, adjacent electrically conductive loops in the plurality of electrically connected electrically conductive loops are attached to each other along at least 60% of their respective perimeters. Brief Description of Drawings

[0010] Exemplary embodiments disclosed herein are more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labelled with the same number.

[0011] FIG. 1A is a photograph illustrating a plan top view of a coil according to an embodiment of the present disclosure;

[0012] FIG. IB is a schematic side view of the coil of FIG. 1A according to an embodiment of the present disclosure;

[0013] FIG. 2A is a schematic perspective view of a multilayer film of the coil of FIG. 1 A according to an embodiment of the present disclosure;

[0014] FIG. 2B is a schematic plan top view of the multilayer film of FIG. 2A according to an embodiment of the present disclosure;

[0015] FIG. 2C is a schematic cross-sectional view of a portion of the coil taken along a line 1-1 of FIG. 1 A according to an embodiment of the present disclosure;

[0016] FIG. 3 A is a photograph illustrating a perspective view of an elastically deformed coil according to an embodiment of the present disclosure;

[0017] FIG. 3B is a photograph illustrating another perspective view of the elastically deformed coil of FIG. 3 A according to an embodiment of the present disclosure;

[0018] FIG. 3C is a schematic side view of an elastically restored coil according to an embodiment of the present disclosure;

[0019] FIG. 4A is a photograph illustrating a perspective view of the coil according to an embodiment of the present disclosure;

[0020] FIG. 4B is a photograph illustrating a perspective view of an elastically deformed coil according to another embodiment of the present disclosure; and

[0021] FIG. 4C is a schematic side view of the elastically deformed coil of FIG. 4B according to an embodiment of the present disclosure.

[0022] Detailed Description

[0023] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0024] In the following disclosure, the following definitions are adopted.

[0025] As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. As used herein as a modifier to a property or attribute, the term “generally,” unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0026] The term “substantially,” unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0027] As used herein, all numbers should be considered modified by the term “about.” The term “about,” unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0028] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0029] As used herein, when a first material is termed as “similar” to a second material, at least 90 weight % of the first and second materials are identical and any variation between the first and second materials comprises less than about 10 weight % of each of the first and second materials.

[0030] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B.”

[0031] As used herein, the term “film” generally refers to a material with a very high ratio of length or width to thickness. A film has two major surfaces defined by a length and width. Films typically have good flexibility and can be used for a wide variety of applications. Films may also be of thickness or material composition, such that they are semi-rigid or rigid. Films described in the present disclosure may be composed of various polymeric materials.

[0032] As used herein, the term “layer” generally refers to a thickness of material within a film that has a relatively consistent chemical composition. Layers may be of any type of material including polymeric, cellulosic, metallic, or a blend thereof. A given polymeric layer may include a single polymer-type or a blend of polymers and may be accompanied by additives. A given layer may be combined or connected to other layers to form films. A layer may be either partially or fully continuous as compared to adjacent layers or the film. A given layer may be partially or fully coextensive with adjacent layers. A layer may contain sub-layers.

[0033] As used herein, the term “between about,” unless otherwise specifically defined, generally refers to an inclusive or a closed range. For example, if a parameter X is between about A and B, then A < X < B.

[0034] Coils described herein may be useful for transfer of information (e.g., digital or analogue data) or energy (e.g., energy for wireless charging). For example, the coils can be useful in the wireless charging of batteries that power electronic devices, such as cellular telephones. The coils can serve to guide magnetic fields during wireless charging, to shield the battery and / or other electronic device components from electromagnetic fields, to reduce eddy currents induced by magnetic fields, and / or to enhance transfer efficiency and / or Q factor of wireless charging systems, for example.

[0035] Substantially concentric loops of a coil may have a same or close center (e.g., centered to within 20%, or within 10%, or within 5% of a largest lateral dimension (e.g., diameter of outermost loop). Substantially concentric loops can have a substantially circular, elliptical, or rounded rectangular shape, for example.

[0036] The present disclosure relates to a coil. The coil includes a multilayer film wound to form a plurality of substantially concentric loops and substantially planar opposing first and second major surfaces of the coil. The multilayer film includes at least one electrically conductive first layer. The multilayer film further includes an elastically deformable adhesive second layer substantially coextensive with the at least one electrically conductive first layer in length along a winding direction of the coil and in width generally along a thickness direction of the coil. The elastically deformable adhesive second layer bonds adjacent loops to each other. The elastically deformable adhesive second layer is configured to elastically deform to at least change relative positions of at least some of the adjacent loops while maintaining the bonding between the adjacent loops.

[0037] The coil of the present disclosure may be elastically deformable from a first coil configuration (i.e., an undeformed configuration) to a second coil configuration (i.e., an elastically deformed configuration) to change various electrical and magnetic properties associated with the coil based on desired application attributes. The coil may have different electrical and magnetic properties in the second coil configuration than that in the first coil configuration.

[0038] Elastically deforming the coil may change an alternating current (AC) resistance and / or an AC inductance thereof. The coil may therefore be elastically deformed to adjust the AC resistance and / or the AC inductance thereof based on desired application attributes. Moreover, elastically deforming the coil may change a magnetic field produced by the coil when energized. The coil may therefore be elastically deformed to adjust or redistribute the magnetic field produced by the coil when energized, based on desired application attributes.

[0039] Advantageously, the coil may be substantially elastically restorable from the second coil configuration to the first coil configuration. The coil may therefore be substantially elastically restored from the second coil configuration to the first coil configuration to restore the electrical and magnetic properties of the coil close to that in the first coil configuration, if desired. Moreover, the coil may be suitable for use in applications requiring a three-dimensionally shaped coil as well as a planar shaped coil, as the shape of the coil may be readily changed between a three-dimensional shape and a substantially planar shape.

[0040] Referring now to the figures, FIGS. 1 A and IB illustrate a coil 200 according to an embodiment of the present disclosure. Specifically, FIG. 1 A illustrates a plan top view of the coil 200 and FIG. IB illustrates a side view of the coil 200.

[0041] The coil 200 defines mutually orthogonal x-, y-, and z-directions. The x- and y-directions correspond to in-plane axes of the coil 200, while the z-direction corresponds to a transverse axis disposed along a thickness of the coil 200. In other words, the x- and y-directions are disposed along a plane (i.e., the x-y plane) of the coil 200, and the z-direction is disposed perpendicular to the plane of the coil 200. The x-direction may be interchangeably referred to as “the first in-plane direction” and the y-direction may be interchangeably referred to as “the second in-plane direction” of the coil 200. Further, the z-direction may be interchangeably referred to as “the thickness direction” of the coil 200.

[0042] As will be described herein, the coil 200 is electrically conductive and elastically deformable. Therefore, the coil 200 may be interchangeably referred to as “the elastically deformable electrically conductive coil 200.” The terms “coil” and “elastically deformable electrically conductive coil” are interchangeable herein.

[0043] Referring to FIGS. 1A and IB, the coil 200 includes a plurality of electrically connected electrically conductive loops 20 (hereinafter also referred to as “the plurality of loops 20”). The plurality of loops 20 may be substantially concentric.

[0044] Specifically, in some embodiments, the coil 200 includes a multilayer film 10 (also shown in FIG. 2 A) wound to form the plurality of substantially concentric loops 20. In other words, each of the loops 20 may include the multilayer film 10 wound to form the loop 20.

[0045] The plurality of loops 20 may include an innermost loop 21 and an outermost loop 23. The innermost loop 21 may include a first longitudinal end 22 of the coil 200. The outermost loop 23 may include a second longitudinal end 24 of the coil 200. The first longitudinal end 22 may be one longitudinal end of the multilayer film 10, and the second longitudinal end 24 may be the other longitudinal end of the multilayer film 10. The plurality of loops 20 may further include adjacent loops 25. The adjacent loops 25 may include two loops 20 from the plurality of loops 20 that are adjacent to each other.

[0046] The multilayer film 10 further forms substantially planar opposing first and second major surfaces 30, 31 of the coil 200. Specifically, the multilayer film 10 may form the first major surface 30 that is substantially planar and the second major surface 31 that is substantially planar and opposite to the first major surface 30 of the coil 200. The coil 200 may have an average thickness t defined between the first major surface 30 and the second major surface 31 along the thickness direction (i.e., the z- direction).

[0047] FIGS. 2A and 2B illustrate the multilayer film 10 according to an embodiment of the present disclosure. Specifically, FIG. 2A illustrates a perspective view of the multilayer film 10, and FIG. 2B illustrates a plan top view of the multilayer film 10. FIG. 2C illustrates a schematic cross-sectional view of a portion of the coil 200 taken along a line 1-1 of FIG. 1A according to an embodiment of the present disclosure.

[0048] The multilayer film 10 defines mutually orthogonal xl-, yl-, and zl-directions. The xl- and y 1-directions correspond to in-plane axes of the multilayer film 10, while the zl-direction corresponds to a transverse axis disposed along a thickness of the multilayer film 10. In other words, the xl- and yl-directions are disposed along a plane (i.e., the xl-yl plane) of the multilayer film 10, and the zl- direction is disposed perpendicular to the plane of the multilayer film 10. The multilayer film 10 may have a thickness t’ along the zl -direction.

[0049] As discussed above, the multilayer film 10 may be wound to form the plurality of loops 20 (shown in FIG. 1 A). The xl-direction of the multilayer film 10 may correspond to a winding direction 201 (shown in FIG. 1A) of the coil 200 and the y 1-direction of the multilayer film 10 may correspond to the thickness direction (i.e., the z-direction) of the coil 200.

[0050] Referring to FIGS. 1 A-2C, the multilayer film 10 includes at least one electrically conductive first layer 40 (hereinafter referred to as “the electrically conductive first layer 40”) and an elastically deformable adhesive second layer 50 (hereinafter interchangeably referred to as “the elastically deformable adhesive 50”). The elastically deformable adhesive second layer 50 is substantially coextensive with the electrically conductive first layer 40 in length L along the winding direction 201 (shown in FIG. 1 A) of the coil 200 and in width W generally along the thickness direction (i.e., the z- direction) of the coil 200. Further, the elastically deformable adhesive second layer 50 may be substantially co-extensive with the electrically conductive first layer 40 in length L generally along the x 1 -direction of the multilayer fdm 10 and in width W generally along the y 1 -direction of the multilayer film 10. The elastically deformable adhesive second layer 50 bonds the adjacent loops 25 to each other.

[0051] In some embodiments, the electrically conductive first layer 40 may include at least two electrically conductive first layers 40 bonded to each other by a substantially inelastic adhesive layer 60. The at least two electrically conductive first layers 40 and the substantially inelastic adhesive layer 60 may be substantially co-extensive with each other in length L along the winding direction 201 of the coil 200 and in width W generally along the thickness direction of the coil 200. Further, the substantially inelastic adhesive layer 60 may be substantially co-extensive with each of the at least two electrically conductive first layers 40 in length L generally along the xl-direction of the multilayer film 10 and in width W generally along the y 1-direction of the multilayer film 10.

[0052] In some embodiments, the multilayer film 10 may further include at least one electrically insulative cover layer 70 (hereinafter referred to as “the electrically insulative cover layer 70”) substantially co-extensive with the electrically conductive first layer 40 in length L along the winding direction 201 of the coil 200 and in width W generally along the thickness direction of the coil 200. Further, the electrically insulative cover layer 70 may be substantially co-extensive with the electrically conductive first layer 40 in length L generally along the xl-direction of the multilayer film 10 and in width W generally along the y 1-direction of the multilayer film 10.

[0053] As shown in FIG. 2A, in some embodiments, the electrically conductive first layer 40 may include a plurality of electrically conductive first layers 40, the substantially inelastic adhesive layers 60 may include a plurality of substantially inelastic adhesive layers 60, and the electrically insulative cover layer 70 may include a plurality of electrically insulative cover layers 70.

[0054] The plurality of electrically conductive first layers 40 may be bonded to each other by the corresponding plurality of substantially inelastic adhesive layers 60. Specifically, at least one substantially inelastic adhesive layer 60 from the plurality of substantially inelastic adhesive layers 60 may be disposed between two adjacent electrically conductive first layers 40 from the plurality of electrically conductive first layers 40 to bond the two adjacent electrically conductive first layers 40 to each other. In some embodiments, at least one substantially inelastic adhesive layer 60 from the plurality of substantially inelastic adhesive layers 60 may be disposed between one electrically insulative cover layer 70 from the plurality of electrically insulative cover layers 70 and one electrically conductive layer 40 from the plurality of electrically conductive layers 40.

[0055] The electrically conductive first layer 40 may include any suitable electrically conductive material, such as a metal. In some embodiments, the electrically conductive first layer 40 may include one or more of copper, aluminum, silver, and gold. The elastically deformable adhesive second layer 50 may include any suitable elastically deformable adhesive, such as adhesives including silicone, polyurethane, acrylic, polylactide, poly hydroxybutyrate, and blends thereof. In some embodiments, an elastic modulus of the elastically deformable adhesive second layer 50 may be less than an elastic modulus of the electrically conductive first layer 40.

[0056] Referring to FIGS. 1A-2B, in some embodiments, each of the substantially planar first and second major surfaces 30, 31 may include corresponding edge surfaces 40a, 50a; 40b, 50b of the electrically conductive first and the elastically deformable adhesive second layers 40, 50. Specifically, the first major surface 30 of the coil 200 may include the edge surface 40a of the electrically conductive first layer 40 and the edge surface 50a of the elastically deformable adhesive second layer 50. Further, the second major surface 31 of the coil 200 may include the edge surface 40b of the electrically conductive first layer 40 and the edge surface 50b of the elastically deformable adhesive second layer 50. In some embodiments, the edge surface 40a of the electrically conductive first layer 40 and the edge surface 50a of the elastically deformable adhesive second layer 50 may be substantially co-planar. In some embodiments, the edge surface 40b of the electrically conductive first layer 40 and the edge surface 50a of the elastically deformable adhesive second layer 50 may be substantially co-planar.

[0057] The substantially inelastic adhesive layer 60 may have opposing edge surfaces 60a, 60b. The first major surface 30 of the coil 200 may further include the edge surface 60a, and the second major surface 31 of the coil 200 may further include the edge surface 60b of the substantially inelastic adhesive layer 60. Further, the electrically insulative cover layer 70 may have opposing edge surfaces 70a, 70b. The first major surface 30 of the coil 200 may further include the edge surface 70a, and the second major surface 31 of the coil 200 may further include the edge surface 70b of the electrically insulative cover layer 70.

[0058] In some embodiments, the edge surface 70a of the electrically insulative cover layer 70, the edge surface 60a of the substantially inelastic adhesive layer 60, the edge surface 40a of the electrically conductive first layer 40, and the edge surface 50a of the elastically deformable adhesive second layer 50 may be substantially co-planar. In some embodiments, the edge surface 70b of the electrically insulative cover layer 70, the edge surface 60b of the substantially inelastic adhesive layer 60, the edge surface 40b of the electrically conductive first layer 40, and the edge surface 50b of the elastically deformable adhesive second layer 50 may be substantially co-planar. Referring to FIGS. 1 A-2C, as discussed above, the elastically deformable adhesive second layer 50 bonds the adjacent loops 25 to each other. The elastically deformable adhesive second layer 50 is configured to elastically deform to at least change relative positions of at least some of the adjacent loops 25 while maintaining the bonding between the adjacent loops 25. As a result, the coil 200 may be elastically deformable along each of the x-direction, the y-direction, and the z-direction. Furthermore, the substantially inelastic adhesive layer 60 may substantially maintain a relative position of the at least two electrically conductive first layers 40 in each of the at least some of the adjacent loops 25.

[0059] The coil 200 shown in FIGS. 1 A, IB, and 2C is in a first coil configuration 202. The first coil configuration 202 may refer to an undeformed configuration of the coil 200. The coil 200 may be substantially planar in the first coil configuration 202. The coil 200 may be elastically deformed in at least one of the x-direction, the y-direction, and the z-direction to transition the coil 200 from the first coil configuration 202 to a second coil configuration. The second coil configuration may refer to an elastically deformed configuration of the coil 200. The coil 200 may be three-dimensional or substantially planar in the second coil configuration. The coil 200 may be elastically deformable between at least the first coil configuration 202 and the second coil configuration in which a same dimension of the coil 200 elastically changes by at least 20%. That is, in the second coil configuration of the coil 200, the same dimension of the coil 200 elastically changes by at least 20% than that in the first coil configuration 202. The same dimension may include one or more of a thickness, a length, a width, and a diameter of the coil 200. Furthermore, in each of the first coil configuration 202 and the second coil configuration, the adjacent loops 25 may be attached to each other along at least 60% of their respective perimeters.

[0060] The coil 200 may be elastically deformable from the first coil configuration 202 to the second coil configuration to change various electrical and magnetic properties associated with the coil 200 based on desired application attributes. The coil 200 may have different electrical and magnetic properties in the second coil configuration than that in the first coil configuration 202.

[0061] For example, elastically deforming the coil 200 may change an alternating current (AC) resistance and / or an AC inductance thereof. As a result, for a given frequency, an elastically deformed coil (i.e., the coil 200 in the second coil configuration) may have a different AC resistance and / or the AC inductance than that of the coil 200 in the first coil configuration 202. Advantageously, the coil 200 may be elastically deformed to adjust the AC resistance and / or the AC inductance thereof based on desired application attributes. Moreover, the elastically deformed coil (i.e., the coil 200 in the second coil configuration) may be elastically restored to its pre-deformed shape (i.e., the shape of the coil 200 in the first coil configuration 202) to restore the original AC resistance and / or the AC inductance thereof, if desired.

[0062] As another example, elastically deforming the coil 200 may change a magnetic field produced by the coil 200 when energized. The coil 200 may therefore be elastically deformed to adjust or redistribute the magnetic field produced by the coil 200 when energized, based on desired application attributes.

[0063] FIGS. 3A and 3B illustrate perspective views of an elastically deformed coil 205 according to an embodiment of the present disclosure.

[0064] Referring to FIGS. 1A, 3A, and 3B, the elastically deformed coil 205 may be formed from the coil 200. The coil 200 may be elastically deformed from the first coil configuration 202 to a second coil configuration 203 to form the elastically deformed coil 205. Specifically, the coil 200 may be elastically deformable between at least the first and second coil configurations 202, 203 in which the same dimension of the coil 200 elastically changes by at least 20%. As discussed above, the same dimension of the coil 200 may include one or more of the thickness, the length, the width, and the diameter of the coil 200. As shown in FIGS. 3 A and 3B, the coil 200 (shown in FIG. 1 A) is elastically deformable between at least the first and second coil configurations 202, 203 in which the thickness of the coil 200 elastically changes by at least 20%. The coil 200 may be elastically deformed along the thickness direction (i.e., the z-direction) from the first coil configuration 202 to the second coil configuration 203 to form the elastically deformed coil 205

[0065] Referring to FIGS. 1A, IB, 2A-2C, 3A, and 3B, in some embodiments, the to at least change the relative positions of the at least some of the adjacent loops 25 (see FIGS. 1A and 2C) may include changing the relative positions of the at least some of the adjacent loops 25 along the thickness direction of the coil 200 resulting in the elastically deformed coil 205 and at least one of the first and second major surfaces 30, 31 (see FIGS. IB and 2C) no longer being substantially planar. In some embodiments, in a plan top view of the elastically deformed coil 205 (i.e., a view where the z-direction is perpendicular to the page), the plurality of loops 20 may remain substantially concentric.

[0066] The relative positions of the at least some of the adjacent loops 25 may be changed along the thickness direction of the coil 200 by use of a coil support 80. The coil support 80 may be movable relative to the coil 200 and may at least partially engage the coil 200 to elastically deform the coil 200. The coil support 80 may have any suitable shape based on a desired deformed shape of the coil 200. The shape of the elastically deformed coil 205 may depend upon the shape of the coil support 80. As shown in FIGS. 3A and 3B, the coil support 80 may have a conical shape, such that the elastically deformed coil 205 has a conical helix shape. In some examples, the coil 200 may be stretched to about 62.5% of its diameter along the thickness direction of the coil 200.

[0067] Further, when the relative positions of the at least some of the adjacent loops 25 along the thickness direction of the coil 200 are changed to result in the elastically deformed coil 205, the substantially inelastic adhesive layer 60 may substantially maintain a relative position of the at least two electrically conductive first layers 40 in each of the at least some of the adjacent loops 25. That is, when the coil 200 is elastically deformed (by virtue of the elastically deformable adhesive second layer 50) by changing relative positions of at least some of the adjacent loops 25 from the plurality of loops 20 in the thickness direction (or the z-direction of the coil 200) to form the elastically deformed coil 205, the substantially inelastic adhesive layer 60 may substantially maintain the relative position of the at least two electrically conductive first layers 40 in each of the at least some of the adjacent loops 25.

[0068] Referring to FIGS. 1A, 2A, 3 A, and 3B, in some embodiments, in each of the first and second coil configurations 202, 203, the adjacent loops 25 in the plurality of loops 20 may be attached to each other along at least 60% of their respective perimeters. In some embodiments, in each of the first and second coil configurations 202, 203, the adjacent loops 25 in the plurality of loops 20 may be attached to each other along at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% of their respective perimeters.

[0069] Specifically, in each of the first and second coil configurations 202, 203, the adjacent loops 25 in the plurality of loops 20 may be attached to each other via the elastically deformable adhesive 50 along the at least 60% of their respective perimeters. In some embodiments, in each of the first and second coil configurations 202, 203, the adjacent loops 25 in the plurality of loops 20 may be attached to each other via the elastically deformable adhesive 50 along the at least 65%, the at least 70%, the at least 75%, the at least 80%, the at least 85%, the at least 90%, or the at least 95% of their respective perimeters.

[0070] In some embodiments, in each of the first and second coil configurations 202, 203, the adjacent loops 25 in the plurality of loops 20 may include an inner loop 26 (see FIG. 1 A) having an outermost perimeter Pl and an outer loop 27 (see FIG. 1 A) having an innermost perimeter P2. The inner and outer loops 26, 27 may be attached to each other along at least 60% of the outermost perimeter P2 of the inner loop 26 and the innermost perimeter P2 of the outer loop 27. Specifically, the inner and outer loops 26, 27 may be attached to each other along the at least 60% of the outermost perimeter P2 of the inner loop 26 and the innermost perimeter P2 of the outer loop 27 via the elastically deformable adhesive 50. In some embodiments, in each of the first and second coil configurations 202, 203, the inner and outer loops 26, 27 may be attached to each other along at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% of the outermost perimeter Pl of the inner loop 26 and the innermost perimeter P2 of the outer loop 27.

[0071] Referring to FIGS. 1A, IB, 3A and 3B, in some embodiments, the elastically deformed coil 205 may have a maximum thickness tl of at least 3 times the average thickness t (shown in FIG. IB) of the coil 200. In some embodiments, the maximum thickness tl may be of at least 4, at least 5, at least 10, at least 20, at least 30, at least 40, or at least 50 times the average thickness t of the coil 200.

[0072] As discussed above, the coil 200 may be elastically deformed to change the alternating current (AC) resistance (or impedance) thereof. For a given frequency, the elastically deformed coil 205 (i.e., the coil 200 in the second coil configuration 203) may have a different AC resistance than that of the coil 200 in the first coil configuration 202.

[0073] Specifically, in some embodiments, at at least a frequency of about 148 kilohertz (kHz), the coil 200 (see FIG. 1 A) and the elastically deformed coil 205 (see FIGS. 3 A and 3B) may have respective AC resistances R0 and Rl. In other words, in some embodiments, at the at least the frequency of about 148 kHz, the coil 200 may have the AC resistance R0, and the elastically deformed coil 205 may have the AC resistance Rl. R1 may be different from RO by at least 5%. In some embodiments, R1 may be different from RO by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, or at least 50%.

[0074] In some examples, for a given frequency, the elastically deformed coil 205 (i.e., the coil 200 in the second coil configuration 203) may have a different AC inductance than that of the coil 200 in the first coil configuration 202.

[0075] Specifically, in some embodiments, at at least the frequency of about 148 kilohertz (kHz), the coil 200 (see FIG. 1 A) and the elastically deformed coil 205 (see FIGS. 3 A and 3B) may have respective AC inductances LO and L 1. In other words, in some embodiments, at the at least the frequency of about 148 kHz, the coil 200 may have the AC inductance LO, and the elastically deformed coil 205 may have the AC inductance LI. LI may be different from LO by at least 5%. In some embodiments, LI may be different from LO by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, or at least 50%.

[0076] The AC resistance and the AC inductance may be measured using an LCR meter or a BH analyzer. In some examples, two ends (i.e., the first and second longitudinal ends 22, 24) of the coil 200 may be connected to the LCR meter to measure the AC resistance and the AC inductance.

[0077] Referring to FIGS. 1A, IB, and 3A-3C, in some embodiments, the elastically deformed coil 205 may be configured to be substantially elastically restored to its pre-deformation shape (i.e., a shape of the coil 200 in the first coil configuration 202 of FIG. 1A) resulting in an elastically restored coil 206 (shown in FIG. 3C).

[0078] The elastically restored coil 206 may have an average thickness t2 within 30% of the average thickness t (shown in FIG. IB) of the coil 200. In some embodiments, the average thickness t2 may be within 25%, within 20%, within 15%, within 10%, or within 5% of the average thickness t of the coil 200.

[0079] The elastically restored coil 206 may further have an AC resistance R2 at the at least the frequency of about 148 kHz within 30% of R0. In some embodiments, the AC resistance R2 at the at least the frequency of about 148 kHz may be within 25%, within 20%, within 15%, within 10%, or within 5% of R0.

[0080] The elastically restored coil 206 may further have an AC inductance L2 at the at least the frequency of about 148 kHz within 30% of L0. In some embodiments, the AC inductance L2 at the at least the frequency of about 148 kHz may be within 25%, within 20%, within 15%, within 10%, or within 5% of L0.

[0081] Advantageously, the coil 200 may be elastically deformed to form the elastically deformed coil 205 and subsequently elastically restored to form the elastically restored coil 206. The elastically restored coil 206 may have similar electrical and magnetic properties to that of the coil 200 in the first coil configuration 202. The coil 200 may therefore be suitable for use in applications requiring a three- dimensionally shaped coil (e.g. the shape of the elastically deformed coil 205) as well as a planar shaped coil (e.g., the shape of the coil 200 in the first coil configuration 202 and the elastically restored coil 206), as the shape of the coil 200 may be readily changed between a three-dimensional shape and a substantially planar shape.

[0082] FIG. 4A illustrates a perspective view of the coil 200 according to another embodiment of the present disclosure. FIGS. 4B and 4C illustrate an elastically deformed coil 210 according to another embodiment of the present disclosure. Specifically, FIG. 4B illustrates a perspective view of the elastically deformed coil 210 and FIG. 4C illustrates a side view of the elastically deformed coil 210.

[0083] The coil 200 of FIG. 4A is in the first coil configuration 202 (i.e., the undeformed configuration). The coil 200 may be elastically deformed from the first coil configuration 202 to a second coil configuration 204 to form the elastically deformed coil 210. Specifically, the coil 200 may be elastically deformable between at least the first and second coil configurations 202, 204 in which the same dimension of the coil 200 elastically changes by at least 20%. As discussed above, the same dimension of the coil 200 may include one or more of the thickness, the length, the width, and the diameter of the coil 200. As shown in FIG. 4B, the coil 200 is elastically deformable between at least the first and second coil configurations 202, 204 in which the diameter of the coil 200 elastically changes by at least 20%. The coil 200 may be elastically deformed along at least the first in-plane direction (i.e., the x-direction of the coil 200) from the first coil configuration 202 to the second coil configuration 204 to form the elastically deformed coil 205.

[0084] Referring to FIGS. 1 A, 2C, and 4A-4B, in some embodiments, the to at least change the relative positions of the at least some of the adjacent loops 25 may include changing the relative positions of the at least some of the adjacent loops 25 along at least the first in-plane direction (i.e., x-direction of the coil 200) resulting in the elastically deformed coil 210 and the at least some of the adjacent loops 25 no longer being substantially concentric.

[0085] When energized, the coil 200 may generate a magnetic field. The coil 200 in the aforementioned configuration (i.e., the second coil configuration 204) may generate a magnetic field inclined toward the first in-plane direction. Specifically, when energized, the elastically deformed coil 210 may produce a stronger magnetic field inclined towards the first in-plane direction as compared to the coil 200 in the first coil configuration 202. Therefore, the coil 200 may be elastically deformed to adjust or redistribute the magnetic field produced by the coil 200 when energized, based on desired application attributes.

[0086] Referring to FIGS. 1A, 2C, and 4A-4C, in some embodiments, in each of the first and second coil configurations 202, 204, the adjacent loops 25 in the plurality of loops 20 may be attached to each other along at least 60% of their respective perimeters. In some embodiments, in each of the first and second coil configurations 202, 204, the adjacent loops 25 in the plurality of loops 20 may be attached to each other along at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% of their respective perimeters.

[0087] Specifically, in each of the first and second coil configurations 202, 204, the adjacent loops 25 in the plurality of loops 20 may be attached to each other via the elastically deformable adhesive 50 along the at least 60% of their respective perimeters. In some embodiments, in each of the first and second coil configurations 202, 204, the adjacent loops 25 in the plurality of loops 20 may be attached to each other via the elastically deformable adhesive 50 along the at least 65%, the at least 70%, the at least 75%, the at least 80%, the at least 85%, the at least 90%, or the at least 95% of their respective perimeters.

[0088] In some embodiments, in each of the first and second coil configurations 202, 204, the inner and outer loops 26, 27 may be attached to each other along at least 60% of the outermost perimeter P2 of the inner loop 26 and the innermost perimeter P2 of the outer loop 27. The inner and outer loops 26, 27 may be attached to each other along the at least 60% of the outermost perimeter P2 of the inner loop 26 and the innermost perimeter P2 of the outer loop 27 via the elastically deformable adhesive 50. In some embodiments, in each of the first and second coil configurations 202, 204, the inner and outer loops 26, 27 may be attached to each other along at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% of the outermost perimeter Pl of the inner loop 26 and the innermost perimeter P2 of the outer loop 27.

[0089] Referring to FIG. 4C, the elastically deformed coil 210 may have a maximum thickness t3 that is within about 30% of the average thickness t (shown in FIG. IB) of the coil 200. In some embodiments, the maximum thickness t3 may be within about 25%, within about 20%, within about 15%, within about 10%, or within about 5% of the average thickness t of the coil 200.

[0090] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0091] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

CLAIMSWhat is claimed is:

1. A coil comprising a multilayer film wound to form a plurality of substantially concentric loops and substantially planar opposing first and second major surfaces of the coil, the multilayer film comprising at least one electrically conductive first layer and an elastically deformable adhesive second layer substantially co-extensive with the first layer in length along a winding direction of the coil and in width generally along a thickness direction of the coil, the elastically deformable adhesive second layer bonding adjacent loops to each other and configured to elastically deform to at least change relative positions of at least some of the adjacent loops while maintaining the bonding between the adjacent loops.

2. The coil of claim 1, wherein the concentric loops comprise an innermost loop comprising a first longitudinal end of the coil and an outermost loop comprising a second longitudinal end of the coil, and wherein the each of the substantially planar first and second major surfaces comprises corresponding edge surfaces of the first and second layers.

3. The coil of claim 1, wherein the to at least change the relative positions of the at least some of the adjacent loops comprises changing the relative positions of the at least some of the adjacent loops along the thickness direction of the coil resulting in an elastically deformed coil and at least one of the first and second major surfaces no longer being substantially planar, and wherein in a plan top view of the elastically deformed coil, the loops remain substantially concentric.

4. The coil of claim 3, wherein the elastically deformed coil has a maximum thickness of at least 3 times an average thickness of the coil.

5. The coil of claim 4, wherein at at least a frequency of about 148 kHz, the coil and the elastically deformed coil have respective alternating current (AC) resistances RO and Rl, wherein R1 is different from RO by at least 5%.

6. The coil of claim 5, wherein the elastically deformed coil is configured to be substantially elastically restored to its pre-deformation shape resulting in an elastically restored coil having an average thickness and an alternating current (AC) resistance R2 at the at least the frequency of about 148 kHz, wherein the average thickness of the elastically restored coil is within 30% of the average thickness of the coil, and wherein R2 is within 30% of RO.

7. The coil of claim 4, wherein at at least a frequency of about 148 kHz, the coil and the elastically deformed coil have respective alternating current (AC) inductances LO and LI, wherein LI is different from LO by at least 5%, and wherein the elastically deformed coil has a maximum thickness that is within about 30% of an average thickness of the coil.

8. The coil of claim 7, wherein the elastically deformed coil is configured to be substantially elastically restored to its pre-deformation shape resulting in an elastically restored coil having an average thickness and an alternating current (AC) inductance L2 at the at least the frequency of about 148 kHz, wherein the average thickness of the elastically restored coil is within 30% of the average thickness of the coil, and wherein L2 is within 30% of LO.

9. The coil of claim 1, wherein the to at least change the relative positions of the at least some of the adjacent loops comprises changing the relative positions of the at least some of the adjacent loops along at least a first in-plane direction of the coil resulting in an elastically deformed coil and the at least some of the adjacent loops no longer being substantially concentric.

10. The coil of claim 1, wherein an elastic modulus of the elastically deformable adhesive second layer is less than an elastic modulus of the at least one electrically conductive first layer.

11. The coil of claim 1 , wherein the at least one electrically conductive first layer comprises at least two electrically conductive first layers bonded to each other by a substantially inelastic adhesive layer, the at least two electrically conductive first layers and the substantially inelastic adhesive layer substantially co-extensive with each other in length along the winding direction of the coil and in width generally along the thickness direction of the coil, and wherein when the relative positions of the at least some of the adjacent loops along the thickness direction of the coil are changed to result in an elastically deformed coil, the substantially inelastic adhesive layer substantially maintains a relative position of the at least two electrically conductive first layers in each of the at least some of the adjacent loops.

12. An elastically deformable electrically conductive coil comprising a plurality of electrically connected electrically conductive loops, the elastically deformable electrically conductive coil elastically deformable between at least first and second coil configurations in which a same dimension of the coil elastically changes by at least 20%, wherein in each of the first and second coil configurations, adjacent electrically conductive loops in the plurality of electrically connected electrically loops are attached to each other along at least 60% of their respective perimeters.

13. The elastically deformable electrically conductive coil of claim 12, wherein each of the loops comprises a multilayer film wound to form the loop.

14. The elastically deformable electrically conductive coil of claim 12, wherein in each of the first and second coil configurations, adjacent electrically conductive loops in the plurality of electrically connected electrically loops comprises an inner loop having an outermost perimeter and an outer loop having an innermost perimeter, and wherein the inner and outer loops are attached to each other along at least 60% of the outermost perimeter of the inner loop and the innermost perimeter of the outer loop.

15. The elastically deformable electrically conductive coil of claim 12, wherein in each of the first and second coil configurations, the adjacent electrically conductive loops in the plurality of electrically connected electrically loops are attached to each other via an elastically deformable adhesive along the at least 60% of their respective perimeters.

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