GB2569536A

GB2569536A - Wireless power for a hearing device

Info

Publication number: GB2569536A
Application number: GB1721139.2A
Authority: GB
Inventors: Aazami Sahba; Frei Christian; Winkler Thomas
Original assignee: Sonova AG
Current assignee: Sonova Holding AG
Priority date: 2017-12-18
Filing date: 2017-12-18
Publication date: 2019-06-26
Also published as: GB201721139D0

Abstract

A hearing device 105 configured to receive wireless power, comprising a charging circuit 225 that has a charging coil 250, where the charging coil is at least partially wrapped around a speaker 255 for the hearing device, and a ferrite spacer disposed between the charging coil and the speaker. The charging circuit can regulate wireless power received by the charging coil and supply power to the hearing aid (e.g., to charge its battery or power components of the hearing device). A charging coil is generally a metal (e.g., copper, iron, or composite metal} that is configured to receive wireless power. The device may also comprise a rechargeable battery 220, and an antenna 245, switch 240 (for example a button or user control), and a microphone 235. The ferrite spacer may for a removable sleeve, or may comprise adhesive between the spacer and the speaker.

Description

The following terms are registered trade marks and should be read as such wherever they occur in this document:

Bluetooth

Zigbee

Wifi

Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo

WIRELESS POWER FORA HEARING DEVICE

TECHNICAL FIELD [0001] The disclosed technology generally relates to a hearing device configured to receive wireless power. In particular, the disclosed technology relates to a hearing device with a charging circuit that has a charging coil, where the charging coil is at least partially wrapped around a speaker for the hearing device, and a ferrite spacer is disposed between the charging coil and the speaker. The charging circuit can regulate wireless power received by the charging coil and supply power to the hearing device (e.g„ to charge its battery).

BACKGROUND [0002] Due to the miniaturization of hearing devices, a small amount of space is available inside of a hearing device. This small amount of space makes it difficult to add components or increase the size of existing components. Additionally, hearing device users want hearing devices with more functionality such as wireless communication and wireless power (e.g., wireless charging). However, additionally functionality can require additional components or larger components.

[0003] For example, US Patent Published Application No. 2004/0028251, titled 'Spacesaving antenna arrangement for hearing aid device,_ filed August 5, 2013, discloses an antenna charging coil arrangement with an antenna for wireless communication wrapped around a receiver. However, this application only discloses a space-savings antenna and fails to disclose other spacing savings arrangements or power savings features of a hearing device. Accordingly, a need exits to provide other space-saving features or additional features for hearing devices.

BRIEF DESCRIPTION OF THE DRAWINGS [0004] The accompanying figures disclose some implementations of the disclosed technology.

[0005] Figure 1 is a wireless charging environment for hearing devices in accordance with some implementations of the disclosed technology.

[0006] Figure 2 is a perspective view for an in-the-ear (ITE) hearing device inserted into the human ear, where the ITE is configured to wirelessly receive power in accordance with some implementations of the disclosed technology.

[0007] Figures 3A-3B are perspective views of a speaker configured in accordance with some implementations of the disclosed technology.

[0008] Figures 4A-4C are cross-sectional views of a speaker configured in accordance with some implementations of the disclosed technology.

DETAILED DESCRIPTION [0009] The disclosed technology generally relates to a hearing device configured to receive wireless power. In particular, the disclosed technology relates to a hearing device with a charging circuit that has a charging coil, where the charging coil is at least partially wrapped or completely wrapped around a speaker of the hearing device. The hearing device also has a ferrite spacer disposed between the charging coil and the speaker. The charging circuit can regulate wireless power received by the charging coil and supply power to the hearing device (e.g„ to charge its battery or power components of the hearing device such as the processor for the hearing device). A charging coil is comprises a metal wire (e.g„ copper, iron, or composite metal) that is configured to receive wireless power.

[0010] In some implementations, the ferrite spacer can have a circular edge, curved edge, or beveled edges. For example, the ferrite spacer can include four beveled edges so that the charging coil can be wrapped around the speaker in a substantially or approximately circular shape. Substantially or approximately circular generally means that the shape of the charging coil wrapped around the speaker has a perimeter and curvature similar to that of a circle (e.g„ a majority of the charging coil is spaced away from a center point by a radius, r).

[0011] In some i mplementations, the beveled edges can form a 45 degree angle relative to the exterior surface of the speaker. See Figure 4A for more detail. In other implementations, the ferrite spacer can include half-moon, half-dome, or circularly shaped edges that completely surround or partially surround the speaker so that the charging coil can be wrapped in a substantially circular shape. See figures 4A-4C, which disclose different ferrite spacer configurations. In other implementations, the ferrite spacer can be a removable sleeve configured to slide over the speaker.

[0012] In some implementations, the disclosed technology has at least one benefit For example, the chargi ng coi I is wrapped around the speaker to save space because space i nside a hearing device is limited (e.g., no separate area is required for a charging coil in addition to the area for the speaker). Additionally, because a speaker is relatively large compared to other components in a hearing device, a wrapped charging coil around the speaker creates a large area where wireless power can be received, which provides for efficient charging of a hearing device (e.g„ within a few hours and without generating much heat) relative to a smal I er chargi ng coi I or smal I er wi rel ess power receivi ng area.

[0013] In some implementations, another benefit is that the charging coil is wrapped in a substantially circular shape due to the beveled or curved edges of the ferrite spacer, and the circular wrapped shape of the charging coil improves wireless power transfer because the charging coil lacks sharp edges or drastic changes in shape, which improves the efficiency of wireless power transfer. Y et another example of a benefit of the disclosed technology is that a ferrite spacers concentrates magnetic fields. Specifically, ferrite has a greater permeability to magnetic fields than air around and concentrates the magnetic field to improve wireless power transfer. Additionally, the ferrite spacer reduces electromagnetic interference with the speaker (e.g„ an interior coil, located in the interior of the speaker, used to produce audio).

[0014] Figure 1 is a wireless charging environment 100 for a hearing device. The wireless charging environment 100 includes two hearing devices 105, but each hearing device 105 can be considered individually. In some implementations, the hearing devices 105 are ITE hearing devices configured to be worn by a user to improve hearing.

[0015] The wireless charging environment 100 also includes a charging station 110. The charging station 110 has inlets 115a and 115b for storing or holding the hearing devices 105 for wireless charging. In some implementations, the inlets 115a and 115b are custom shaped to fit the hearing devices 105. In other implementations, the inlets 115a and 115b are a generic shape (e.g„ circle, square) that forms an area for wireless charging. As shown in Figure 1, the charging station 110 has the inlets 115a and 115b where the narrow part of the hearing devices 105 can fit within the shape of the inlets 115a and 115b. The wireless power can be transmitted through induction, magnetic fields, electromagnetic fields, or related means using an electromagnetic field. If the charging station 110 is using inductive charging, the charging station 110 can include charging coils 120a and 120b to generate a magnetic or electromagnetic field for charging each hearing device 105.

[0016] The charging station 110 is configured to transmit wireless power (e.g., through induction). In some implementations, the frequency for inductive charging can be 50 to 300 kHz or in an industrial, scientific, and medical (ISM) frequency band. The ISM bands can include 6.700 MHz to 6.795 MHz, 13.553 MHz to 13.567 MHz, 26.957 MHz to 27.283 MHz, 40.66 MHz to 40.7 MHz, 433.05 MHz to 434.79 MHz, 902 MHz to 928 MHz, 2.4 GHz to 2.5 GHz, or 5.725 GHz to 5.875 GHz. The frequency for charging can be selected based on 3 desired charging time, charging temperature, size of battery, and availability or capability of the charging station 110 to supply power at a frequency. In some implementations, it is preferred to oscillate an electromagnetic charging field below 7 MHz, preferably below 300kHz, where the electromagnetic charging field is applied to a hearing device and the hearing device includes a rechargeable battery configured to power the hearing device.

[0017] Although the charging station 110 is shown as a box or storage area, the charging station 110 can also be a pad or contact area where a user can place the hearing devices 105 for wireless charging. The charging station 110 can also include a lid configured to open and close so that the hearing devices can be covered during charging. The charging station can be composed of material that reduces the strength of electromagnetic radiation such as metal, composite material, or other materials for shielding.

[0018] Figure 2 is a perspective view for the hearing device 105 inserted into a human ear 205, where the hearing device is configured to receive power wirelessly. For example, a user can insert the hearing device 105 into his or her ear during the day, and then take the hearing device out before he or she goes to sleep at night. During the night, the user can place the hearing device 105 in the charging station 110 (Figure 1) to recharge the hearing device 105. The charging station 110 can charge the hearing device 105 partially or completely. Although the hearing device 105 is shown as an ITE in Figure 2, the hearing device 105 can be also be a Behind-The-Ear (BTE), Receiver-Canal (RIC), In-The-Ear (ITE), or Completely-In-Canal (CIC), and Invisible-In-The-Canal (IIC) device.

[0019] The hearing device 105 includes a processor 210. The processor 210 can include sped al-purpose hardware such as application specific integration circuits (ASICS), programmable logic devices (PL Ds), field-programmable gate arrays (FPGAs), programmable circuitry (e.g., one or more microprocessors microcontrollers), Digital Signal Processor (DSP), appropriately programmed with software and/or firmware, or a combination of special purpose hardware and programmable circuitry. In some implementations, the processor 210 is physically and electronically coupled to memory such as volatile memory, nonvolatile memory and dynamic memory, wherein the memory stores algorithms for providing audio to a user. In some implementations, the processor 210 receives audio or audio information (e.g„ from an antenna) and the processor 210 processes the audio so that a hearing impaired individual can better understand (or hear) it This can be referred to as 'processed audio_, which can included adding gain, changing phase, compressing or uncompressing audio, or other digital signal processing techniques for audio. The processor 210 provides the processed audi o to the speaker 255.

[0020] In some implementations, the process 210 is electronically coupled to a charging circuit 225, where the process 210 and the charging circuit 225 enable the power management and regulation of power for the hearing device 105. In some implementations, the charging circuit 225 is an electronic circuit configured to regulate or transfer power from the charging coil 250 to other parts of the hearing device 105. For example, the charging circuit 225 can transfer received wireless power from the changing coil 250 to a battery 220. In some implementations, the charging coil 225 can regulate power independent of the processor 210, and the processor 210 can simply receive power from the charging circuit or the battery 220. In some implementations, the charging circuit 225 provides power to the battery 220, where the battery is a rechargeable battery (e.g„ Li-on).

[0021] The hearing device 105 also includes a vent 200, a battery 220, a faceplate 230, a microphone 235 (e.g., a pressure difference microphone, a micro-electro-mechanical system also referred to as 'MEMSJ, a switch 240 (e.g„ a button or user control), an antenna 245, a charging coil 250 wrapped partially or completely around a speaker 255, where a ferrite spacer 252 is disposed between the charging coil 250 and the speaker 255. The hearing device 105 also includes an opening 280 in a shell 283 (e.g„ plastic, composite, or metal and plastic material). In some implementations, the shell 283 and the faceplate 230 can be separate or individual components that are glued together or mechanically coupled together.

[0022] The shell 283 and the faceplate 230 coupled together can surround some components such as the battery 220, and the opening 280 in the shell 283 enables the transmission of sound. In some implementations, the battery 220 is a rechargeable battery (e.g., Li-ion) or zinc-air battery. In some implementations, the faceplate 230 is physically integrated into the shell 283. The faceplate 230 provides an aesthetically pleasing exterior and a low profile to not draw attention to the hearing device 105 when worn by a user.

[0023] The charging coil 250 comprises copper or another metal that enables the reception of electromagnetic energy. The charging coil 250 is configured to receive wireless power for the frequencies described in Figure 1 (e.g„ ISM frequencies). In some implementations, the size of the charging coil 250 can vary in width and length to provide enough area to receive enough wireless power to charge the battery 220 within 24 hours (e.g., 23, 12, 6, 5, or less than 4 hours), wherein providing enough power depends on the size of the battery and desired charging time for the hearing device. In some implementations, the charging coil 250 is electronically coupled to the charging circuit 225 via wires (e.g„ copper wires).

[0024] The vent 200 enables the flow of air between the inner and outer parts of the ear through the hearing device 105. In some implementations, the vent 200 can improve hearing for a user because sound i s propagated through the vent 200 or the vent 200 enabl es the i ntake or release of pressure (e.g., to reduce occlusion). Although not shown in Figure 2, the vent 200 can include a door that opens and closes completely or partially, which can occur manually or automatically (e.g., with an electromagnetic component). The vent 200 can be moved from the inside of the hearing device 105 to the outside (e.g„ adjacent to the shell 283 or physi cal ly coupl ed to the shel I 283).

[0025] The antenna 245 can communicate with the computing devices using Bluetoothu (e.g„ Bluetooth Classicu , Bluetooth Low Energyu ), Zigbeeu , WiFiu , other 802.11 wireless communication protocol, 10MHz, Hearing Instrument Body Area Network (HiBAN), or other 10-50 MHz binaural wireless communication between hearing devices. Although the antenna 245 is shown in Figure 2, the hearing device 105 can also not have an antenna, e.g., when the hearing device user does not need the hearing device to have wireless connectivity.

[0026] Figures 3A-3B are perspective views of the speaker 255 with the charging coil 250 wrapped around it with the ferrite spacer 252 disposed between the speaker 255 and the chargi ng coi I 250. T he speaker 255 can also i nd ude a spout 305, where the spout 305 enables sound to travel from the speaker 255 towards a person s ear canal or ear drum. In some implementations, the speaker 255 may not have a spout; rather, the speaker 255 can be physically coupled to a tube that enables the transmission of sound or passage of air.

[0027] The ferrite spacer 252 improves the transfer of wireless power because of its material properties (e.g„ focuses an electromagnetic or magnetic field). The ferrite spacer 252 can vary in thickness (e.g., depending on desired efficiency of energy transfer, strength of material, or durability). The ferrite spacer 252 can cover the speaker 255 partially or completely (e.g., the ferrite spacer 252 can have more than 1 piece, but all pieces of the ferrite spacer 252 can be used to partially or completely cover the speaker 252). As shown in Figure 3A, the ferrite spacer 252 covers more than 50% of the exterior surface of the speaker 255. In some implementations, the ferrite spacer 252 covers between 30-100% of the exterior speaker surface, e.g„ 50%, 60%, 70%, 75%, 80%, or 90%. In general, the ferrite spacer 252 is disposed between the charging coil 250 and exterior surface of the speaker 255. In some implementations, the ferrite spacer 252 is presently only where the charging coil is also present [0028] The difference between Figures 3A and 3B is that Figure 3B has a first side 310 wrapped with more charging coil 250 than a second side 315 wrapped with less charging coil. The first side 310 has more charging coil 250 because the charging coil 250 is wrapped around the speaker 255 more times (e.g„ 2, 3, 5, or more times/wraps) on the first side 310 than the second side 315. In some implementations, the charging coil 250 can be composed of two different charging coils on each side, where the left side charging coil is thicker (or longer) and the right-side charging coil is thinner (or shorter). As shown in Figure 3B with the dashed gui del i nes, the fi rst si de 310 is thi cker and the second si de 315 is thi nner (e.g„ has smaller footprint) and this can be helpful in fitting a hearing device in a user s ear canal. Specifically, because an ear canal can get narrower as you move closer to a person's ear drurrt it is helpful if the profile of the hearing device reduces (e.g„ has a smaller or thinner footpri nt) on the si de cl osest to the ear drum. T he difference i n si ze between the fi rst si de 310 and the second side 315 can create a tapering effect that enables a better fit of a hearing device within an ear canal as the ear canal narrows.

[0029] Additionally, improving the fit rate or fit of hearing device can improve performance of the hearing device and customer satisfaction. In particular, guidelines 320 have been added to show that the footprint of the speaker 255 is larger on one side (e.g., the left side in Figure 3B) than on the other side (e.g., the right side of Figure 3B) because the charging coil 250 is wrapped more times on the one side than the other side. However, this size difference creates a tapering effect that improves the fit rate of the hearing device because the shell of the hearing device will also be tapered to fit the speaker 255 and the charging coil 250.

[0030] Figures 4A-4C are cross-sectional views of the speaker 255, the ferrite spacer 252, and the charging coil 250, that show the ferrite spacer 252 may not be a solid piece or one piece; rather, the ferrite spacer 252 can be multiple pieces or have different shaped edges as shown in Figures4A-4C.

[0031] Figure 4A illustrates a cross-sectional view of the speaker 255, where the speaker 255 has a square or rectangle cross-section. On the exterior of the speaker 255 there are four ferrite spacers 405a-d, and each ferrite spacer has two beveled edges with a 45 degree angle. The beveled edges enable the charging coil 205 to be wrapped in a substantially circular shape, which improves the efficiency of the charging coil relative to a straight coil orcoil with sharp edges. The ferrite spacers 405a-d can be glued to the speaker 255 with an adhesive material 407. In some implementations, the ferrite spacers 405a-d can have a beveled edge with less than a 45 degree angle (e.g„ 40, 35, or less) as long as the charging coil 250 can be wrapped around in a substantially circular shape. In some implementations, the ferrite spacer 405a can be the first ferrite spacer, 405b is the second ferrite spacer, 405c is the third ferrite spacer, and 405d is the fourth ferrite spacer.

[0032] Figure 4B is also a cross-sectional view of the speaker 255, where the speaker 255 has a square or rectangle cross-section, with the charging coil 250 and the ferrite spacers 410a-d. The ferrite spacers 410a-d differ from ferrite spacers 405a-d because the ferrite spacers 410ad have a curved outer edge. The curved outer edge enables the charging coil to be wrapped around the speaker 255 in a substantially circular shape. The adhesive material 407 adheres the ferrite spacers 410a-d to the speaker. In some implementations, the ferrite spacer 410a can be the fi rst ferrite spacer, 41 Ob is the second ferrite spacer, 41 Oc is the thi rd ferrite spacer, and 41 Od is the fourth ferrite spacer, where each ferrite spacer has a flat edge proxi mate to the speaker 255 and a curved edge away from the speaker 255 (e.g„ opposite the flat edge).

[0033] Figure 4C illustrates a cross-sectional area of the speaker 255 and a ferrite sleeve 425. The ferrite sleeve 425 is one solid piece of ferrite or composite material (e.g„ ferrite and another metallic material). The ferrite sleeve 425 defines a cavity 420, wherein the cavity is configured to house the speaker 255. In some implementations, the speaker 255 can be slide into the cavity 420 during the manufacture of the hearing device 105 (Figure 2). One advantage of the sleeve configuration is that the ferrite sleeve 425 can be replaced if the charging coil 250 is defective or the ferrite sleeve 425 can be re-used when the speaker 255 is defective and replaced.

Conclusion [0034] Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; in the sense of including, but not limited to. As used herein, the terms connected, coupled, or any variant thereof means any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, electromagnetic, or a combination thereof. Additionally, the words herein, above, below, and words of similar import when used in this application, refer to this application and not to any portions of thi s appl i cati on. W here the context permi ts, words i n the above D etai I ed D escri pti on usi ng the singular or plural number may also include the plural or singular number respectively.

The word or, in reference to a list of two or more items, covers all the following interpretations of the word: any of the items in the list; all of the items in the list, any combi nation of the items i n the I ist, or a si ngle item i n the I ist [0035] The teachings of the technology provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various examples described above can be combined to provide further implementations of the technology. Some alternative implementations of the technology may include not only additional elements to those i mpl ementati ons noted above, but al so may i nd ude fewer el ements.

[0036] The terms used in the following claims should not be construed to limit the technology to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the technology encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the technology under the claims. For example, speaker 255 can also be referred to a 'receiver, or a 'transducer, configured to transfer electrical or mechanical energy into a sound wave. The speaker 255 can also be referred to as a loudspeaker.

[0037] To reduce the number of dai ms, certai n aspects of the technology are presented below in certain claim forms, but the applicant contemplates the various aspects of the technology in any number of claim forms. For example, while only one aspect of the technology is recited as a computer-readable medium clairrt other aspects may likewise be embodied as a computer-readable medium claim, or in otherforms, such as being embodied in a means-plusfunction claim [0038] Also, the figures are not drawn to scale and have various viewpoints and perspectives. Some components or operations shown in the figures may be separated into different blocks or combined into a single block for the purposes of discussion of some implementations of the disclosed technology (e.g„ the battery can be combined with the charging circuit in Figure 2A). Although the disclosed technology is amenable to various modifications and alternative forms, specific implementations have been shown by way of example in the figures and are described in detail below. The intention, however, is not to limit the disclosed technology to the particular implementations. Rather, the disclosed technology is intended to cover all modifications, equivalents, and alternatives falling within the scope of the disclosed technology as defined by the appended claims.

Example Implementations [0039] The following examples are implementations of the disclosed technology. In some implementations, the disclosed technology includes a hearing device, the hearing device comprising a speaker (e.g„ speaker 255 from Figure 2) configured to provide processed audio to a user; a charging circuit (e.g„ charging circuit 225 from Figure 2) configured to receive wireless power to at least partially power the speaker (e.g., speaker 255), wherein the charging circuit comprises a charging coil (e.g., charging coil 250), wherein the charging coil is at least partially wrapped around the speaker; and a ferrite spacer (e.g., 405a-d, 410a-d, or 425) at least partially disposed between the speaker (255) and the charging coil (250), wherein the ferrite spacer (e.g„ 405a-d, 410a-d, or 425) has a shape configured to enable substantially circular wrapping of the charging coil (250). In some implementations, the ferrite space is a first ferrite space, and the hearing device further comprises: a second ferrite spacer at least partially disposed between the speaker and the charging coil; a third ferrite spacer at least partially disposed between the speaker and the charging coil; and a fourth ferrite spacer at least partially disposed between the speaker and the charging coil, wherein the first, second, third, and fourth spacers each have at least one beveled edge. In some implementations, the hearing device further comprises adhesive material between the ferrite spacer and the speaker.

[0040] The ferrite space can be a first ferrite space, and the hearing device can further comprise: a second ferrite spacer at least partially disposed between the speaker and the charging coil; a third ferrite spacer at least partially disposed between the speaker and the charging coil; and a fourth ferrite spacer at least partially disposed between the speaker and the charging coil, wherein the first, second, third, and fourth spacers each have at least one curved edge. In some implementations, the hearing device further comprises adhesive material between the ferrite spacer and the speaker.

[0041] The hearing device can further comprise: a rechargeable battery (e.g„ battery 220 in Figure 2); and a charging circuit (e.g„ Figure 2). The charging coil can be wrapped around at least half or 50% of the speaker and the hearing device can further comprise: an antenna; a switch; and a microphone (e.g„ Figure 2). In some implementations, the hearing device further comprises adhesive material between the ferrite spacer and the speaker.

[0042] In some implementations, the charging coil is wrapped around a first side of the receiver twice and a second side of a receiver once, wherein the first side is thicker than the second side. In some implementations, the hearing device further comprises adhesive material between the ferrite spacer and the speaker.

[0043] In other implementations, the ferrite spacer forms a removable sleeve. And in some implementations, the hearing device is configured to receive wireless power from a charging station, wherein the charging station comprises includes two inlets configured to receive hearing devices, and wherein the charging device is configured to transmit wireless power using an industrial, scientific, and medical (ISM) band (e.g„ Figure 1).

Claims

1. A hearing device, the hearing device comprising:

a speaker configured to provide processed audio to a user;

a charging circuit configured to receive wireless power to at least partially power the speaker, wherein the charging circuit comprises a charging coil, wherein the charging coil is at least partially wrapped around the speaker; and a ferrite spacer at least partially disposed between the speaker and the charging coil, wherein the ferrite spacer has a shape configured to enable substantially circular wrapping of the charging coil.

2. The hearing device of claim, wherein the ferrite space is a first ferrite space, and the hearing device further comprises:

a second ferrite spacer at least partially disposed between the speaker and the charging coil;

a thi rd ferrite spacer at I east parti al ly di sposed between the speaker and the chargi ng coi I; and a fourth ferrite spacer at least partial ly disposed between the speaker and the chargi ng coi I, wherein the first, second, third, and fourth spacers each have at least one beveled edge.

3. The hearing device of claim 1, wherein the ferrite space is a first ferrite space, and the hearing device further comprises:

a thi rd ferrite spacer at I east parti al ly di sposed between the speaker and the chargi ng coi I; and a fourth ferrite spacer at least partially disposed between the speaker and the charging coil, wherein the first, second, third, and fourth spacers each have at least one curved edge.

4. The hearing device of claim 1, further comprising:

a rechargeable battery.

5. The hearing device of claim 1, wherein the charging coil is wrapped around at least half of the speaker.

6. The hearing device of claim 1, wherein the hearing device further comprises:

an antenna;

a switch; and a mi crophone.

7. The hearing device of claim 1, wherein the charging coil is wrapped around at least 50% the speaker.

8. The hearing device of claim 1, wherein the charging coil is wrapped around a first side of the receiver twice and a second side of a receiver once, wherein the first side is thicker than the second side.

9. The hearing device of claim 1, wherein the ferrite spacer forms a removable sleeve.

10. The hearing device of claim 1, wherein the hearing device is configured to receive wireless power from a charging station, wherein the charging station comprises two inlets configured to receive hearing devices, and wherein the charging station is configured to transmit wireless power with an industrial, scientific, and medical (ISM) band.

11. The hearing device of claim 1, further comprising adhesive material between the ferrite spacer and the speaker.