WO2024073393A1

WO2024073393A1 - Improved coil fabrication

Info

Publication number: WO2024073393A1
Application number: PCT/US2023/075094
Authority: WO
Inventors: Phyo Aung KYAW; Aaron Stein
Original assignee: Resonant Link, Inc.
Priority date: 2022-09-27
Filing date: 2023-09-26
Publication date: 2024-04-04

Abstract

Described herein are improved electromagnetic components and methods of fabricating such components that suitable for use in a wireless power transfer system (e.g., as a wireless power transfer coil). Electromagnetic components described herein may exhibit high efficiency and may be manufactured using fabrication techniques described herein at low cost. An electromagnetic component may be formed with alternating conductive layers and dielectric layers and a first conductive layer of the conductive layers may have a plurality of first conductor layers. An electromagnetic component may have a structure comprising alternating conductor and dielectric layers and the structure may have a packing factor of greater than 20% wherein the packing factor is a ratio of a volume of the conductor layers to a volume of the dielectric layers.

Description

IMPROVED COIL FABRICATION

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No.: 63/410,393, filed September 27, 2022, under Attorney Docket No.: R0830.70011US00, and titled “IMPROVED COIL FABRICATION,” which is hereby incorporated by reference in its entirety.

BACKGROUND

I. Technical Field

[0002] The systems and techniques described herein relate to wireless power transfer and to electromagnetic components as may be used in a resonator, including within a wireless power transfer system.

II. Discussion of the Related Art

[0003] An electromagnetic component is an at least partially inductive and at least partially capacitive component. One example of an electromagnetic component is an inductive- capacitive (LC) resonator. An LC resonator supports alternating current (AC) signals at one or more frequencies that are dependent on the inductance and capacitance of the resonator. In principle, LC resonance occurs at frequencies at which energy may be regularly oscillated between electric fields stored in the capacitance of the resonator and magnetic fields stored in the inductance of the resonator. In practice, an LC resonator may be operated off-resonance.

[0004] In wireless charging, a wireless power transmitter generates an alternating current in a wireless power transmit coil, which induces a current in a wireless power receive coil by electromagnetic induction. The term “wireless power transfer coil” refers herein to either a wireless power receive coil or a wireless power transmit coil, and to coils that may perform the function of wireless power reception or transmission (e.g., in different modes).

BRIEF SUMMARY

[0005] Some aspects relate to a method of forming an electromagnetic component, comprising: forming a structure comprising alternating conductor layers and dielectric layers, wherein forming a first conductor layer of the conductor layers comprises disposing or forming a plurality of first conductor layers. [0006] The disposing or forming a plurality of first conductor layers may comprise depositing or printing the plurality of first conductor layers in contact with one another. [0007] Each of the first conductor layers may have a thickness within 25% of a maximum thickness of a process for forming the first conductor layers.

[0008] The structure may comprise an inductive coil of the electromagnetic component.

[0009] Some aspects relate to an electromagnetic component, comprising: conductor layers; and dielectric layers disposed between at least some of the conductor layers, wherein a first conductor layer of the conductor layers comprises a plurality of conductor layers in contact with one another.

[0010] The electromagnetic component may comprise a wireless power transfer coil.

[0011] The electromagnetic component may comprise an inductive-capacitive (LC) resonator.

[0012] The plurality of conductor layers may be disposed directly adjacent one another. [0013] The plurality of conductor layers may not be separated by a dielectric layer.

[0014] The plurality of conductor layers may form an inductive coil winding.

[0015] Some aspects relate to an electromagnetic component, comprising: a structure comprising alternating conductor layers and dielectric layers, wherein the structure has a packing factor of greater than 20%, wherein the packing factor is a ratio of a volume of the conductor layers to a volume of the dielectric layers.

[0016] The conductor layers may form an inductive coil winding.

[0017] The structure may comprise a multilayer ceramic capacitor (MLCC) structure comprising therein an inductive-capacitive (LC) resonator.

[0018] Some aspects relate to a method of forming an electromagnetic component, comprising: forming the coil in a multilayer ceramic capacitor (MLCC) manufacturing process without an outer packaging dielectric or removing the outer packaging dielectric form a structure formed in a multilayer ceramic capacitor process.

[0019] The electromagnetic component may comprise a wireless power transfer coil.

[0020] The electromagnetic component may comprise an inductive-capacitive (LC) resonator.

[0021] The electromagnetic component may comprise an inductive coil winding.

[0022] Some aspects relate to a method of forming an electromagnetic component, comprising: adhering a first substrate comprising alternating conductor and dielectric layers with a second substrate comprising alternating conductor and dielectric layers; and before or after the adhering, reducing a thickness of a top or bottom dielectric layer of the first substrate.

[0023] Some aspects relate to an electromagnetic component comprising: a first substrate comprising alternating conductor and dielectric layers; and a second substrate comprising alternating conductor and dielectric layers, wherein the first substrate is adhered to the second substrate at surfaces of the first and second substrates, respectively, from which exterior layers of the first and second substrates, respectively, have been etched away.

[0024] The first substrate may comprise a first printed circuit board (PCB) and the second substrate may comprise a second PCB.

[0025] The electromagnetic component may comprise a wireless power transfer coil.

[0026] The electromagnetic component may comprise an inductive-capacitive (LC) resonator.

[0027] The electromagnetic component may comprise an inductive coil winding.

[0028] Some aspects relate to a method of forming an electromagnetic component, comprising: adhering a first substrate comprising alternating conductor and dielectric layers with a second substrate comprising alternating conductor and dielectric layers using a material between the first and second substrates with a melting point lower than that of the first and second substrates.

[0029] The first substrate may comprise a first printed circuit board (PCB) and the second substrate may comprise a second PCB.

[0030] Some aspects relate to an electromagnetic component comprising: a first substrate comprising alternating conductor and dielectric layers; a second substrate comprising alternating conductor and dielectric layers; and a material adhering the first substrate to the second substrate and having a melting point lower than melting points of the first and second substrates.

[0031] The first substrate may comprise a first printed circuit board (PCB) and the second substrate may comprise a second PCB.

[0032] Some aspects relate to a method of forming an electromagnetic component, comprising: forming a structure comprising alternating conductor layers and dielectric layers; and forming a filler section to at least partially compensate for a reduced height in a region of the electromagnetic component where conductor of the conductor layers is absent.

[0033] The filler section may comprise a conductor or dielectric material.

[0034] Some aspects relate to an electromagnetic component comprising: a structure comprising alternating conductor layers and dielectric layers; and a filler section configured to at least partially compensate for a reduced height in a region of the electromagnetic component where conductor of the conductor layers is absent.

[0035] The filler section may comprise a conductor or dielectric material.

[0036] Some aspects relate to a system comprising: any one of the preceding electromagnetic components; and a power and/or data transmitter and/or receiver configured to transfer power and/or data via the electromagnetic component.

[0037] The foregoing summary is provided by way of illustration and is not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like reference character. For purposes of clarity, not every component may be labeled in every drawing. The drawings are not necessarily drawn to scale, with emphasis instead being placed on illustrating various aspects of the techniques and devices described herein.

[0039] FIG. 1 A is top perspective view of an example electromagnetic component having a single-layer thin-layer conductive winding, according to some embodiments.

[0040] FIG. IB is a top perspective view of an example electromagnetic component having a multi-layer thin-layer conductive winding, according to some embodiments.

[0041] FIG. 2 is a side view of a cross-section of an example electromagnetic component having alternating conductive and dielectric layers, according to some embodiments.

[0042] FIG. 3 A is a side view of a cross-section of an example electromagnetic component having a first layer of conductor formed on a substrate, according to some embodiments. [0043] FIG. 3B is a side view of a cross-section of the electromagnetic component of FIG.

3 A further having a second layer of conductor formed on the first layer of conductor, according to some embodiments.

[0044] FIG. 3C is a side view of a cross-section of the electromagnetic component of FIG.

3B further having a dielectric layer over the first and second layers of conductor, according to some embodiments.

[0045] FIG. 3D is a side view of a cross-section of the electromagnetic component of FIG. 3C having additional layers of conductor and an additional dielectric layer over the first and second layers of conductor and dielectric layer, according to some embodiments.

[0046] FIG. 4 is a side view of a cross-section of an example electromagnetic component having a plurality of PCBs stacked together, according to some embodiments. [0047] FIG. 5 is a side view of a cross-section of an example electromagnetic component having a plurality of PCBs adhered together by a material with a lower melting point than the PCBs, according to some embodiments.

[0048] FIG. 6A is a top view of an example electromagnetic component having a filler section deposited in a gap in a C-shaped conductor, according to some embodiments.

[0049] FIG. 6B is a top view of an example electromagnetic component having filler sections in gaps between adjacent conductors, according to some embodiments.

[0050] FIG. 7A is a block diagram of an example wireless power transfer system that may incorporate electromagnetic components described herein, according to some embodiments. [0051] FIG. 7B is an example of a wireless power receiver that may incorporate electromagnetic components described herein, according to some embodiments.

[0052] FIG. 7C is an example of a wireless power transmitter that may incorporate electromagnetic components described herein.

DETAILED DESCRIPTION

I. Introduction

[0053] The inventors have developed improved electromagnetic components and methods of fabricating such components that are suitable for use in a wireless power transfer system (e.g., as a wireless power transfer coil). Electromagnetic components described herein may exhibit high efficiency and may be manufactured using fabrication techniques described herein at low cost.

II. Overview of Electromagnetic Components for Wireless Power Transfer [0054] FIG. 1 A is top perspective view of an example electromagnetic component 100a having a single-layer thin-layer conductive coil winding 110a, according to some embodiments. FIG. IB is a top perspective view of an example electromagnetic component 100b having a multi-layer thin-layer conductive winding 110b, according to some embodiments.

[0055] In some embodiments, an electromagnetic component may be a wireless power transfer coil that includes a conductive winding. A wireless power transfer coil may be configured as an LC resonator that determines the operating frequency or frequencies of wireless power transfer. Alternatively or additionally, a wireless power transfer coil may have some capacitance therein such that the coil itself is an LC resonator determining the operating frequency or frequencies of wireless power transfer. In some embodiments, the conductive winding(s) of the wireless power transfer coil may provide the inductance of an LC resonator, and a capacitor may be included in the wireless power transfer coil to provide the capacitance of the LC resonator. Alternatively or additionally, the conductive winding(s) may have some capacitance therein such that the winding(s) form an LC resonator. In some embodiments, a wireless power transfer coil may have capacitive structures formed of conductive and/or dielectric components within the coil structure. Alternatively or additionally, lumped capacitive elements may be coupled between parts of a wireless power transfer coil structure to provide capacitance.

[0056] In each of FIGs. 1A-1B, the electromagnetic component 100a, 100b includes a magnetic core 102 having a winding region 104 therein in which the thin-layer conductive windings 110a, 110b are disposed. The winding region 104 may be at least partially enclosed, such as having an outer rim surrounding the winding 110a, 110b, while including one or more openings to expose the leads LI, L2 of the winding 110a, 110b, as shown in FIGs. 1 A- 1B. A signal may be applied across and/or received from the leads LI, L2 to use the electromagnetic component.

[0057] Thin-layer windings are windings of one or more thin-layer conductors. Thin layer conductors are electrical conductors in which the thickness of the winding is much smaller than its width (e.g., at least 10 times smaller). For example, the thin-layer winding 110a shown in FIG. 1 A may be formed of a conductive foil having a thickness (in the vertical direction T) much smaller than its width W (in the radial direction R). For a thin-layer winding with a plurality of turns (wrapping in a circumferential direction C), the thin-layer winding has a thickness that is much smaller (e.g., at least 10 times smaller) than the width W (along the radial direction R) of all the turns in the thin-layer winding. For example, in FIG. IB, the width of the thin-layer winding 110b is the radial extent of the winding across all three traces, which in this case are three turns connected in series.

[0058] In some embodiments, the magnetic core 102 may be, wholly or partially, made of one or more ferromagnetic materials, which have a relative permeability of greater than 1, optionally greater than 10. The magnetic core materials may include, but are not limited to, one or more of iron, various steel alloys, cobalt, ferrites including manganese-zinc (MnZn) and/or nickel-zinc (NiZn) ferrites, nanogranular materials such as Co-Zr-O, and powdered core materials made of powders of ferromagnetic materials mixed with organic or inorganic binders. However, the techniques and devices described herein are not limited as to the particular material of the magnetic core. The shape of the magnetic core may be: a pot core, a sheet (I core), a sheet with a center post, a sheet with an outer rim, RM core, P core, PH core, PM core, PQ core, E core, EP core, or EQ core, by way of example. However, the techniques and devices described herein are not limited to the particular magnetic core shape.

[0059] In some embodiments, capacitance may be added to the structures shown in FIGs. 1 A and IB, such as by coupling a lumped capacitor between the leads LI, L2. Alternatively or additionally, in some embodiments, such as shown in FIG. 1 A, at least some capacitance may be provided by the coil winding 110a itself, such as between adjacent conductors.

[0060] Some examples of thin-layer conductors or their applications may include, but are not limited to, foil layers forming a flat current loop (e.g. C-shaped, arc-shaped, rectangularshaped, or any polygon-shaped conductors); edge-wound conductors; printed circuit boards; multilayer self-resonant structures (U.S. Patent 10,109,413 and 10,707,011, U.S. Patent Application Publication No. 2021/0304949, which is incorporated herein in its entirety); inductively coupled current loops (U.S. Patent Application Publication No. 2022/0246349, which is incorporated herein in its entirety); multilayer conductors with integrated capacitance (U.S. Patent Application Publication No. 2023/0253147, which is incorporated herein in its entirety); and low-frequency resonant structure (U.S. Patent Application Publication No. 2023/0253147, which is incorporated herein in its entirety), and any of the foil conductors mentioned before in which the conductor is patterned.

[0061] A wireless power transfer coil may be formed of any type of conductors, including, but not limited to: PCB traces, foil, conductors laminated on substrate layers, inductively coupled current loops, multilayer self-resonant structures, electrode layers in multilayer ceramic capacitor (MLCC) processes, electrode layers in low-temperature co-fired ceramic (LTCC) processes, integrated circuit traces and others. The conductors may be planar or non- planar. Examples of non-planar coils include solenoids and barrel-wound coils. The coil or winding may be placed in a magnetic core, but placing a coil or winding in a magnetic core is optional.

[0062] The quality factor (Q) of a wireless power transfer coil affects the efficiency of wireless power transmission. Generally, a higher quality factor Q in the coil allows achieving higher efficiency in overall power transmission from end-to-end because the quality factor Q may be representative of the power efficiency within the coil. For instance, the quality factor Q may be impacted by the conductivity of conductive structures within the coil that are used for wireless power transmission, as a lossy conductive structure within the coil will cause the quality factor Q of the coil to be low, resulting in a low overall power transmission efficiency. [0063] FIG. 2 is a side view of a cross-section of an example electromagnetic component 200 having alternating conductive and dielectric layers, according to some embodiments.

[0064] Coils, such as wireless power transfer coils, may be formed of layers of thin-layer conductors, with adjacent conductor layers being separated by dielectric layers. FIG. 2 illustrates the coil of the electromagnetic component 200 may include a stack of conductor layers 202a, 202b, 202c separated by respective dielectric layers 204a, 204b, 204c. A coil may include any number of conductor layers and any number of dielectric layers. Although the dielectric layers 204a, 204b, 204c may electrically separate the conductor layers 202a, 202b, 202c in the illustrated cross-section, the conductor layers 202a, 202b, 202c may be conductively connected in a portion of the electromagnetic component not shown in FIG. 2, such as by winding about a magnetic core (e.g., as shown in FIG. IB).

III. Multi-Layer Conductor Configurations

[0065] The inventors have recognized and appreciated that it would be desirable to maximize the volume of conductors within a given volume, referred to herein as the packing factor, which increases the quality factor Q of an electromagnetic component, particularly at low frequencies of operation (e.g., < 1 MHz in some embodiments). This can be done by reducing the thickness of the dielectric layers, increasing the thickness of the conductor layers or both. For instance, a large conductive volume may have a high overall conductivity and low loss, and thus provide more efficient power transfer. However, there have been limits on the degree to which the thickness of the dielectric layers can be reduced. For example, a minimum dielectric thickness is needed to withstand a given voltage across respective conductor layers. Further, there can be limits on the degree to which the thickness of the conductor layers can be increased. For example, various manufacturing processes may have limits on the thickness of the conductor layer that can be formed.

[0066] The techniques described herein can enable forming coils with stacks of thin-layer conductors and dielectric layers with increased conductor thickness, decreased dielectric layer thickness, or both.

[0067] FIG. 3A is a side view of a cross-section of an example electromagnetic component 300 having a first layer 302a of conductor formed on a substrate 310, according to some embodiments. FIG. 3B is a side view of a cross-section of the electromagnetic component 300 further having a second layer of conductor 302b formed on the first layer of conductor 302a, according to some embodiments. FIG. 3C is a side view of a cross-section of the electromagnetic component 300 further having a dielectric layer 304 over the first and second layers of conductor 302a, 302b, according to some embodiments. FIG. 3D is a side view of a cross-section of the electromagnetic component 300 having additional layers of conductor 302 and an additional dielectric layer 304 over the first and second layers of conductor 302a, 302b and dielectric layer 304, according to some embodiments.

[0068] A conductive layer with increased thickness may be produced by forming or placing two or more layers of the conductor on top of one another, without an intervening dielectric layer. For example, as illustrated in FIG. 3A, a first layer of conductor 302a may be formed or placed on an underlying substrate 310. A second layer of conductor 302b may then be formed on layer 302a to form a thicker combined conductor layer 302, as illustrated in FIG. 3B. In some embodiments, the thicknesses of conductor layers 302a and 302b may be at or near the limit of the manufacturing process (e.g., within 25% of its rated or maximum thickness). Accordingly, a combined conductor layer 302 may be formed that is thicker than possible using a single conductor deposition or formation step in the manufacturing process. However, the techniques described herein are not limited in this respect, as the thicknesses of conductors 302a and 302b need not be at or near the maximum achievable by the deposition process. Further, the techniques and components described herein are not limited to forming or placing two layers, as in other embodiments, the forming or placing of conductor layers may be performed more than twice to obtain a combined conductor layer 302 formed from more than two depositions or placings of thinner conductor layers.

[0069] As illustrated in FIG. 3C, a dielectric layer 304 may be formed over the combined conductor layer 302. The steps may be repeated any number of times, as illustrated in FIG. 3D, to form a coil having any number of conductor layers. Respective conductor layers 302 may have the same thicknesses as one another, or the thicknesses may vary from layer to layer. Similarly, respective dielectric layers 304 may have the same thicknesses as one another, or the thicknesses may vary from layer to layer.

[0070] The conductors of the conductor layers 302a, 302b be made of any electrically conductive material or combination of materials, including but not limited to one or more metals such as silver, copper, aluminum, gold and titanium, and non-metallic materials such as graphite. The electrically conductive material may have an electrical conductivity of higher than 200 kS/m, optionally higher than 1 MS/m. The electrical conductors may have any physical shape including, but not limited to, solid material, wire, magnet wire, stranded wire, litz wire, foil conductors, conductors laminated on a substrate, printed circuit board traces, electrode layers formed in in multilayer ceramic capacitor (MLCC) or low- temperature co-fired ceramic (LTCC) processes, integrated circuit traces, or any combination of them. They may be formed in metallized film or metallized laminate or PCB processes, for example.

[0071] The dielectric layers 304 may be formed any one or more materials including but not limited to one or more of air, FR4, PL A, ABS, polyimide, PTFE, polypropylene, a mix of PTFE and supporting materials for ease of handling (e.g. Rogers Substrates, Gore Materials, or Taconic TLY materials), plastic, glass, alumina, ceramic, dielectric or ceramic layers in multilayer ceramic capacitor (MLCC) processes, or dielectric or ceramic layers in low- temperature co-fired ceramic (LTCC) processes.

[0072] In some embodiments, the thickness of the dielectric layers can be reduced when there is no voltage difference, or a low voltage difference, between adjacent conductor layers. For example, if the two conductor layers 302 shown in FIG. 3D are at the same voltage at a given position along the horizontal axis of FIG. 3D, the dielectric layer 304 between the two conductor layers 302 does not need to withstand a significant voltage, and can be formed with a small thickness. In some embodiments where the conductor layers 302 have gaps, the voltage may be made the same in adjacent conductor layers 302, by aligning their gaps, as discussed in U.S. Patent Application Publication No. 2022/0246349, which is hereby incorporated by reference in its entirety.

IV. Improved Packing Factor Configurations

[0073] As discussed above, it is desirable to increase the packing factor of an electromagnetic component (or a structure therein), where the packing ratio is the ratio of conductor volume to dielectric volume of the structure, to increase the quality factor Q, particularly at low frequencies of operation (e.g., < 1 MHz in some embodiments). The following are packing factors that may be achieved with various techniques using non-limiting examples of layer thicknesses. In a baseline process with single-printing of electrodes and without zero voltage differences between conductor layers, the packing factor may be 20% (5 pm electrodes, 20 pm dielectric layers). Using double or multi- printing of electrodes, zero voltage difference between electrodes, or both, the packing factor can be increased. For example, with doubleprinting the electrodes and without zero voltage difference between electrodes, the packing factor can be 33.33% (10 pm electrodes, 20 pm dielectric layers). As another example, with single-printing of electrodes and with zero voltage difference between conductor layers, the packing factor may be 25% (5 pm electrodes, alternating 10 pm and 20 pm dielectric layers). As a further example, with double-printing the electrodes and with zero voltage difference between electrodes, the packing factor may be 40% (10 pm electrodes, alternating 10 pm and 20 pm dielectric layers). Accordingly, in some embodiments a coil may be formed with a packing factor of greater than 20%, such as between 20% and 40%, by way of example. Some processes may accommodate electrodes of greater thicknesses and/or dielectric layers of smaller thicknesses, which may achieve a packing factor of greater than 40%.

[0074] In some embodiments in which a coil is formed in a MLCC process, the outer packaging dielectric can be omitted to save space and improve packing factor.

V. Stacked Substrate Configurations

[0075] In some embodiments, a coil with multiple stacked conductor layers may be formed in a process that includes stacking a plurality of substrates together, where each substrate has one or more conductor layers. For example, the substrates may be printed circuit boards (PCBs) having a plurality of conductor layers 302 (e.g., FIG. 3D).

[0076] FIG. 4 is a side view of a cross-section of an example electromagnetic component 400 having a plurality of PCBs 410, 420 stacked together, according to some embodiments.

[0077] FIG. 4 illustrates an example of stacked PCBs 410, 420 that may have layers of conductors collectively forming a coil (e.g., FIG. IB). One issue that arises when forming coils from a plurality of stacked PCBs is the thickness of the top and bottom dielectric layers (e.g., outer layers) of the PCB. In FIG. 4, the upper PCB 410 has an upper layer 412 and a lower layer 414 and the lower PCB 420 has an upper layer 422 and a lower layer 424. Outer layers may be relatively thick to allow for plating through-holes. The thickness of such layers is often greater than that of other dielectric layers of the PCB. For example, in 18-micron copper PCBs with plated through-holes, the thickness of the top or bottom dielectric layers may be in the range of 30-40 microns. In FIG. 4, the other dielectric layers of the PCBs 410, 420 are not specifically delineated within the PCBs 410, 420. The greater thickness of the outer layers can lead to high losses in operation.

[0078] Various techniques may be used to avoid incorporation of thick dielectric layers into a coil formed of stacked PCBs. In some embodiments, a PCB with relatively thin outer layers may be used. In some embodiments, the outer layer may be partially or completely removed (e.g., etched) to reduce its thickness. The etching may be performed before or after a plated through-hole process.

[0079] FIG. 5 is a side view of a cross-section of an example electromagnetic component 500 having a plurality of PCBs 510, 520 adhered together by a material 530 with a lower melting point than the PCBs 510, 520, according to some embodiments.

[0080] In some embodiments, PCBs 510, 520 may be adhered together by depositing a material 530 with a lower melting point than the PCBs 510, 520 between them, as illustrated in FIG. 5. When the PCBs 510, 520 with material 530 therebetween is heated, the low melting point material 530 melts, and when the material 530 cools it solidifies and binds the PCBs 510, 520 together. Relatively thick outer dielectric layers of the PCBs 510, 520 may thus be removed or omitted.

VI. Filler Section Configurations

[0081] The inventors have recognized a fabrication issue that can arise when conductors are stacked. Regions without conductors will have a depression of reduced height compared to regions with conductors. The variation in height can lead to fabrication difficulties or reduced performance. To reduce or prevent a variation in height, one or more filler sections may be formed in a region lacking conductive material.

[0082] FIG. 6A is a top view of an example electromagnetic component 600a having a filler section 606a deposited in a gap 604a in a C-shaped conductor 602a, according to some embodiments. FIG. 6B is a top view of an example electromagnetic component 600b having filler sections 606b in gaps 604b between adjacent conductors 602b, according to some embodiments.

[0083] One example with a C-shaped conductor 602a is shown in FIG. 6A. When stacking a plurality of conductors 602a that have gaps 604a in the conductors aligned with one another, an issue can arise in which the gap 604a has a depression formed relative to the conductor 602a, as the gap 604a lacks conductor whereas the conductors 602a may be stacked over multiple layers (e.g., FIGs. 3A, 3D). To help equalize the height, a filler section 606a may be deposited in the gap 604a in the conductor 602a in one or more layers. FIG. 6B shows another example with conductors 602b having a different shape, with filler sections 606b in gaps 604b between adjacent conductors 602b.

[0084] The filler section may be a region of the same material as the conductor, and need not be electrically connected to anything (may be floating). Alternatively, or additionally, the filler section may be an additional region of dielectric material formed in one or more layers. The filler section may be present in any one or more layers, such as all layers, in alternating layers, or every few layers, for example. The filler section may fill up the entire region between areas of conductive material, or only part of the region. The filler section may be, but need not be, a single contiguous region. In some embodiments, the filler section may include a plurality of small, separated regions (e.g., dots) of filler material, or a mesh or net of filler material. The filler material can be formed into any shape, including but not limited to those described above. VII. Example Applications

[0085] FIG. 7A shows a block diagram illustrating an example wireless power transfer system 700 in which a wireless power transmitter 710 is configured to send power to the wireless power receiver 720 via an inductive power flow link, according to some embodiments.

[0086] In some embodiments, one or each of the wireless power transmitter 710 and wireless power receiver 720 may include an electromagnetic component as described herein. For example, wireless power transfer may be effected using a transmit coil and a receive coil, one or each of which comprises a structure described herein.

[0087] It should be appreciated that data may be transmitted in the wireless power transfer system 700 . For example, as shown in FIG. 7A, the wireless power transmitter 710 may communicate with the wireless power receiver 720 through an inductive link (e.g., the same inductive link used to send power from the wireless power transmitter 710 to the wireless power receiver 720). Alternatively, the communication between the wireless power transmitter 710 and the wireless power receiver 720 may be performed though another communication technique (e.g., a different wireless communication technique).

[0088] FIG. 7B shows an example of a wireless power receiver 720 that can receive power from a wireless power transmitter 710, according to some embodiments. As shown in FIG. 7B, the wireless power receiver 720 includes a receive coil 721 that may be inductively coupled to a transmit coil of a wireless power transmitter 710. For example, when the coils of the transmitter 710 and 720 are sufficiently close and/or aligned, inductive coupling may be achieved to transfer power between the coils. While receiving power from the wireless power transmitter 710, the receive coil 721 has an alternating current induced therein by the magnetic field produced by the wireless power transmitter 710. Optionally, the receive coil 721 may be coupled to a matching network (e.g., a capacitor), which is not shown in FIG. 7B, although an inductive-capacitive (LC) network including the coil 721 may be incorporated in a structure described herein. The signal from the receive coil 721 (and optionally processed by the matching network) is then provided to the rectifier 722. The rectifier 722 receives the alternating current from the receive coil 721 and converts it into direct current at the rectifier output 724. The direct current may then be provided to any suitable load, such as a battery charger (not shown), for example. The rectifier 722 may be a full-bridge or half-bridge rectifier. The rectifier 722 may be a synchronous rectifier that is controlled by the controller 723 of the wireless power receiver. [0089] In some embodiments, the wireless power receiver 720 also includes a data receiver 729 for receiving data transmitted from the wireless power transmitter 710, which is received by the wireless power receiver 720 through the inductive coupling to the receive coil 721. [0090] FIG. 7C shows an example of circuitry for a wireless power transmitter 710 including an inverter 712 receiving power from a power input 711, according to some embodiments. In FIG. 7C, the transmitter 710 includes a transmit coil 713, which may include a structure described herein. The inverter 12 may be controlled by a controller 714 to transmit power wirelessly by driving an alternating current through the transmit coil 713. In this example, the wireless power transmitter 710 also includes a data receiver 715 for receiving data transmitted from the wireless power receiver 720, which is received by the wireless power transmitter 710 through the inductive coupling to the transmit coil 713. In other embodiments in which the wireless power transmitter 710 does not receive data from the wireless power receiver 720, the data receiver 715 may be omitted.

[0091] Any of the techniques described herein may be used alone or in any suitable combination.

[0092] Electromagnetic components described herein may be useful for a variety of wireless power transfer applications. For example, electromagnetic components described herein may be used in medical devices, such as implantable medical devices, including subdermal implantable medical devices. For instance, an electromagnetic component may be used for inductive coupling between an external device and an implanted device to effect wireless power charging and/or data transmission between the devices. In such cases, improved an quality factor of an electromagnetic component, as described herein, may generate little heat, making such components suitable for implantation or for an external device that interacts with implanted devices when placed at or proximate skin.

[0093] As another example, electromagnetic components may be used to charge electric vehicles, such as cars or warehouse vehicles such as forklifts. A large amount of power may be transferred efficiently through such electromagnetic components due to their high quality factor, making it faster to charge a vehicle without generating excessive heat.

[0094] It should be appreciated that electromagnetic components described herein are not limited to wireless power transfer and may be used in other technologies. For example, electromagnetic components may be used in LC resonators for other applications, such as for power electronics or other applications where resonators are used.

[0095] Various aspects of the components and techniques described herein may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing description and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.

[0096] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0097] The terms “substantially,” “approximately,” “about” and the like refer to a parameter being within 25%, optionally within 10%, optionally less than 5% of its stated value.

[0098] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

[0099] What is claimed is: CLAIMS

1. A method of forming an electromagnetic component, comprising: forming a structure comprising alternating conductor layers and dielectric layers, wherein forming a first conductor layer of the conductor layers comprises disposing or forming a plurality of first conductor layers.

2. The method of claim 1, wherein the disposing or forming a plurality of first conductor layers comprises depositing or printing the plurality of first conductor layers in contact with one another.

3. The method of claim 1, wherein each of the first conductor layers has a thickness within 25% of a maximum thickness of a process for forming the first conductor layers.

4. The method of claim 1, wherein the structure comprises an inductive coil of the electromagnetic component.

5. An electromagnetic component, comprising: conductor layers; and dielectric layers disposed between at least some of the conductor layers, wherein a first conductor layer of the conductor layers comprises a plurality of conductor layers in contact with one another.

6. The electromagnetic component of claim 5, wherein the electromagnetic component comprises a wireless power transfer coil.

7. The electromagnetic component of claim 5, wherein the electromagnetic component comprises an inductive-capacitive (LC) resonator.

8. The electromagnetic component of claim 5, wherein the plurality of conductor layers are disposed directly adjacent one another.

9. The electromagnetic component of claim 5, wherein the plurality of conductor layers are not separated by a dielectric layer.

10. The electromagnetic component of claim 5, wherein the plurality of conductor layers form an inductive coil winding.

11. An electromagnetic component, comprising: a structure comprising alternating conductor layers and dielectric layers, wherein the structure has a packing factor of greater than 20%, wherein the packing factor is a ratio of a volume of the conductor layers to a volume of the dielectric layers.

12. The electromagnetic component of claim 11, wherein the conductor layers form an inductive coil winding.

13. The electromagnetic component of claim 11, wherein the structure comprises a multilayer ceramic capacitor (MLCC) structure comprising therein an inductive-capacitive (LC) resonator.

14. A method of forming an electromagnetic component, comprising: forming the coil in a multilayer ceramic capacitor (MLCC) manufacturing process without an outer packaging dielectric or removing the outer packaging dielectric form a structure formed in a multilayer ceramic capacitor process.

15. The method of claim 14, wherein the electromagnetic component comprises a wireless power transfer coil.

16. The method of claim 14, wherein the electromagnetic component comprises an inductive-capacitive (LC) resonator.

17. The method of claim 14, wherein the electromagnetic component comprises an inductive coil winding.

18. A method of forming an electromagnetic component, comprising: adhering a first substrate comprising alternating conductor and dielectric layers with a second substrate comprising alternating conductor and dielectric layers; and before or after the adhering, reducing a thickness of a top or bottom dielectric layer of the first substrate.

19. An electromagnetic component comprising: a first substrate comprising alternating conductor and dielectric layers; and a second substrate comprising alternating conductor and dielectric layers, wherein the first substrate is adhered to the second substrate at surfaces of the first and second substrates, respectively, from which exterior layers of the first and second substrates, respectively, have been etched away.

20. The electromagnetic component of claim 19, wherein the first substrate comprises a first printed circuit board (PCB) and the second substrate comprises a second PCB.

21. The electromagnetic component of claim 19, wherein the electromagnetic component comprises a wireless power transfer coil.

22. The electromagnetic component of claim 19, wherein the electromagnetic component comprises an inductive-capacitive (LC) resonator.

23. The electromagnetic component of claim 19, wherein the electromagnetic component comprises an inductive coil winding.

24. A method of forming an electromagnetic component, comprising: adhering a first substrate comprising alternating conductor and dielectric layers with a second substrate comprising alternating conductor and dielectric layers using a material between the first and second substrates with a melting point lower than that of the first and second substrates.

25. The method of claim 24, wherein the first substrate comprises a first printed circuit board (PCB) and the second substrate comprises a second PCB.

26. An electromagnetic component comprising: a first substrate comprising alternating conductor and dielectric layers; a second substrate comprising alternating conductor and dielectric layers; and a material adhering the first substrate to the second substrate and having a melting point lower than melting points of the first and second substrates.

27. The electromagnetic component of claim 26, wherein the first substrate comprises a first printed circuit board (PCB) and the second substrate comprises a second PCB.

28. A method of forming an electromagnetic component, comprising: forming a structure comprising alternating conductor layers and dielectric layers; and forming a filler section to at least partially compensate for a reduced height in a region of the electromagnetic component where conductor of the conductor layers is absent.

29. The method of claim 29, wherein the filler section comprises a conductor or dielectric material.

30. An electromagnetic component comprising: a structure comprising alternating conductor layers and dielectric layers; and a filler section configured to at least partially compensate for a reduced height in a region of the electromagnetic component where conductor of the conductor layers is absent.

31. The electromagnetic component of claim 30, wherein the filler section comprises a conductor or dielectric material.

32. A system comprising: any one of the electromagnetic components of claims 5-13, 19-23, 26-27, and 30-31; and a power and/or data transmitter and/or receiver configured to transfer power and/or data via the electromagnetic component.