Patent Description:
The present disclosure relates to electrodes. In particular, the present disclosure relates to an electrode for a hearing device that electrically couples to skin of a user.

Hearing devices may include hearing aids or a device with a transducer for providing personalized sound to a user's ear. Hearing aids can be used to assist patients suffering hearing loss by transmitting amplified sounds to one or both ear canals. Such devices typically include hearing assistance components, such as a microphone for receiving ambient sound, an amplifier for amplifying the microphone signal in a manner that depends upon the frequency and amplitude of the microphone signal, a speaker or receiver for converting the amplified microphone signal to sound for the wearer, and a battery for powering the components.

In certain types of hearing aids, the hearing assistance components are enclosed by a housing that is designed to be worn in the ear for both aesthetic and functional reasons. Such devices may be referred to as in-the-ear (ITE), in-the-canal (ITC), completely-in-the-canal (CIC) type, or invisible-in-the-canal (IIC) hearing assistance devices. Other types of devices, referred to as receiver-in-canal (RIC) devices, include a receiver housing that is worn in the ear. A portion of the RIC devices may be worn outside of the ear.

It is well known to use electrodes on skin of a patient to monitor one or more conditions. Such electrodes have been used, for example, in a skull cap for brain computer interface (BCI) applications, such as electroencephalography (EEG) or electrooculography (EOG). Such BCI applications may require electrodes that can provide precise electrical measurements of electrical signals present on the skin.

Some existing electrodes may be described as "wet" electrodes and may require an electrolytic liquid, which may be incorporated into a gel, to be placed between the electrode and the skin before each use. The electrolytic liquid may be consumed after each use of the wet electrode. Further, the sensation of electrolytic liquid against the skin may be uncomfortable to many users, particularly on skin areas sensitive to moisture such as the ear canal.

Other existing electrodes may be described as "dry" electrodes, which may not require an electrical coupling gel. However, many dry electrodes require harsh cleaning to prepare the skin before electrode replacement, as well as a significant force to be applied on the skin to establish electrical coupling. Further, dry electrodes may be susceptible to signal drift over time due, for example, to material degradation.

The limitations of existing wet and dry electrodes may be tolerable in a clinical setting for short periods of use. But over extended periods of use, particularly outside of the clinic in many daily wear applications, these limitations may render existing wet and dry electrodes unsuitable, particularly for use in a hearing device.

<CIT> relates to an ear plug for arrangement in an ear canal comprising at least two electrodes for detecting an EEG signal from a skin surface when the ear plug is arranged in the ear canal. The ear plug further comprises a housing having an outer wall. The electrodes are provided with a skin contact part arranged on an outside surface of the housing and connected through the outer wall of the housing to a supporting member on the inner part of the housing. The skin contact part and the supporting member are arranged for clamping the outer wall.

<CIT> refers to an ear plug comprising a shell with at least two electrodes adapted for measuring brain wave signals. The electrodes are connected with means for processing the measured signals. The contours of the outer surface of the ear plug and the electrodes are individually matched to at least part of the ear canal and the concha of the user.

Various aspects of the present disclosure relate to a hearing device including an electrode for electrically coupling to the skin of a user. The hearing device may include a body having a housing and hearing device components. The electrode may be electrically coupled to one or more hearing device components disposed in the body. The electrode may facilitate electrical coupling to skin of a user and may be used as a dry or wet electrode, for example, by utilizing conductive materials or structural designs that provide comfort, good electrical conductivity with the skin, and mitigation of signal drift over time.

In one aspect, the present disclosure relates to a hearing device for electrically coupling to skin of a user. The device includes a body comprising a housing forming at least part of an outer surface. The device also includes an acoustic transducer disposed at least partially in the body. The device further includes an electrode disposed at least partially in the body. The electrode has an outer conductor disposed at least partially in the housing and forming at least part of the outer surface. The electrode also has an inner conductor electrically coupled to the outer conductor and disposed subflush to the outer surface.

In another aspect, the present disclosure relates to a method of making a hearing device comprising a housing and an electrode configured to electrically couple to skin of a user. The method includes providing a cast shell comprising a thin outer wall, a thick outer wall, an inner wall between the thin and thick outer walls, a cavity proximate to the thin outer wall, and a void proximate to the thick outer wall separated from the cavity by the inner wall. The method also includes forming an elastomeric conductor in the cavity of the cast shell. The method further includes removing the thin outer wall to form the housing comprising an outer surface defined at least partially by the thick outer wall and the elastomeric conductor.

In another aspect, the present disclosure relates to a method of making a hearing device comprising a housing and an electrode configured to electrically couple to skin of a user. The method includes forming a shell of the housing, forming a frame of the housing, and disposing at least one hearing device component on the frame. The method also includes inserting the frame into the shell and electrically coupling the electrode to the at least one hearing device component. The electrode is disposed at least partially in the shell.

The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings.

This disclosure relates to electrodes to facilitate electrical coupling to skin of a user. Although reference is made herein to electrodes for a hearing device used in BCI applications, electrodes of this disclosure may be used with any device or application in which electrical coupling to the skin may be desirable. In general, non-limiting examples of devices include hearing aids, hearable devices (for example, earbuds, Bluetooth headsets, or back-vented vented tweeter-woofer devices), wearables or health monitors (for example, step counter or heartrate monitor), or other portable or personal electronics (for example, smartwatch or smartphone). Various other applications will become apparent to one of skill in the art having the benefit of the present disclosure.

It may be desirable to provide an electrode that electrically couples to the skin of the user to facilitate taking precise measurements, which may be desirable in BCI applications. It may also be desirable for the electrode to be capable of use as a dry electrode that is convenient for repeatable use and does not require an electrolytic liquid to achieve precise measurements. Further, it may be desirable to establish electrical coupling between the electrode and the skin without uncomfortable amounts of pressure being applied to the ear canal.

The present disclosure provides an electrode for a hearing device to electrically couple to skin of a user. The hearing device may include a body having a housing and an acoustic transducer disposed at least partially or entirely in the body. The housing may be partially soft, hard, or contoured to facilitate comfortable use. The electrode may include an outer conductor and an inner conductor. The electrode may be electrically coupled to one or more hearing device components disposed in the body, for example, using the inner conductor. The hearing device including the electrode may be formed using a variety of methods to produce different types of electrodes that may be suitable for use in various BCI applications, such as EEG (which may benefit from larger electrodes) or EOG (which may benefit from smaller electrodes). The electrode may include various features, such as microfeatures or electrolytic liquid, to provide a good electrical coupling to the skin (for example, low SNR and few artifacts) without significant pressure being applied to the skin. The electrode may be used as a dry electrode which may facilitate comfortable daily use in non-clinical settings. In particular, the electrode may be suitable for repeated use without the need for adding an electrolytic liquid or other frequent maintenance of the electrode. The electrode may also be used as wet electrode, which may provide an even better electrical coupling to the skin. The hearing device may be used in an environment including a user as shown in <FIG> and <FIG>.

As shown in <FIG>, a hearing device <NUM> may be used in an environment <NUM> and, in particular, used in the ears <NUM> of a user <NUM>. For example, one or more hearing devices <NUM> may be disposed at least partially in the ear canal of each ear <NUM>. The hearing device <NUM> may be a hearing aid. As shown in <FIG>, the hearing device <NUM> may include one or more acoustic transducers <NUM>. Sound may approach the ear <NUM> of the user <NUM> and be received by a receiving acoustic transducer <NUM> (for example, a microphone), which may be positioned to collect sound from the external environment. The sound received may be modulated and transmitted toward an ear drum of the ear <NUM> using a transmitting acoustic transducer <NUM> (for example, a speaker/receiver), which may be on an opposite end of the hearing device <NUM> from the transmitting acoustic transducer.

The hearing device <NUM> may include an electrode <NUM> and an outer surface <NUM>. One or both of the electrode <NUM> and the outer surface <NUM> may be disposed proximate or adjacent to the skin <NUM> of the user <NUM> when the hearing device <NUM> is in use. The electrode <NUM> may be disposed subflush, flush, or superflush to the outer surface <NUM>. In some embodiments, the electrode <NUM> may be disposed between the receiving and transmitting acoustic transducers <NUM>.

A hearing device <NUM> typically includes at least one enclosure or housing and one or more hearing device components, such as one or more transducers <NUM> (for example, a speaker/receiver and a microphone), hearing device electronics including processing electronics, and a power source (for example, a battery). In one or more embodiments, the battery may be rechargeable. In one or more embodiments, multiple energy sources may be employed. The housing of the hearing device <NUM> may be custom made to fit the contours of the user's skin, such as skin in the ear canal, to increase comfort over extended periods of being worn. In some embodiments, one or more transducers may be optional (for example, the microphone may be optional). In some embodiments, the hearing device electronics may include a communication interface (for example, which may include an antenna) to communicate with one or more remote devices (for example, a smartphone, tablet, or other hearing device).

The electrode <NUM> may provide a "good" electrical signal to the electronics in the hearing device <NUM> that is sufficient for use in BCI applications, such as EEG or EOG. In some applications, a "good" electrical signal may be defined quantitatively in terms of an SNR within the range of a skull cap having about <NUM> electrodes. In some embodiments, the electrodes <NUM> of the hearing device <NUM> may be suited to detect frequency bands useful for one or more applications. For example, the electrodes <NUM> of the hearing device <NUM> may detect brain waves, such as alpha waves (about <NUM> to about <NUM>) and delta waves (about <NUM> to about <NUM>).

The electrode <NUM> may be capable of establishing "good" electrical contact with a minimal, or at least acceptable, amount of surface fatigue to the ear. The surface fatigue to the ear may be defined as a measure of user discomfort. In some embodiments, particularly in which the device <NUM> is custom fit to the user's ear, the design of the device <NUM> may define an ear deformation depth or ear deformation protrusion, which may be defined as the distance that the device is designed to deform the surface of the user's ear at a particular location when the device is inserted into the ear as compared to when the ear has no device therein. In general, a greater the ear deformation depth or ear deformation protrusion may facilitate a more secure fitting of the device <NUM> to the user's ear but may also be more likely to cause surface fatigue. On the other hand, too small of an ear deformation depth or ear deformation protrusion may result in poor electrical contact with the skin of the ear for BCI application measurements. In some embodiments, to provide good electrical contact while providing acceptable surface fatigue, the ear deformation depth or dear deformation protrusion may be defined as being less than or equal to about <NUM>, about <NUM>, about <NUM>, or about <NUM>.

<FIG> shows a hearing device <NUM> that may be used to electrically couple to the skin of a user in a diagram view. The hearing device <NUM> may include a body <NUM> having a housing <NUM>. In some embodiments, the housing <NUM> may be formed of any suitable biocompatible material, which may be, for example, a polymer material.

The housing <NUM> may form at least part or all of an outer surface <NUM> of the hearing device <NUM>. In some embodiments, the outer surface <NUM> may be described as an outermost surface of the hearing device <NUM>. The hearing device <NUM> may include an acoustic transducer <NUM>. The acoustic transducer <NUM> may be disposed at least partially in the housing <NUM> of the body <NUM>. The acoustic transducer <NUM> may form at least part of the outer surface <NUM>. In some embodiments, the acoustic transducer <NUM> may be recessed from the outer surface <NUM> (for example, disposed subflush to the outer surface) and be in acoustic communication with the external environment by an aperture formed in the housing <NUM> of the hearing device <NUM>. Preferably, at least one acoustic transducer <NUM> is acoustically coupled with the external environment to receive sound.

The hearing device <NUM> includes one or more electrodes <NUM>. In some embodiments, the hearing device <NUM> may include a plurality of electrodes <NUM>. An electrical signal may be measured using the electrode <NUM>, for example, between two or more electrodes <NUM> of the same hearing device <NUM>, between two hearing devices (for example, one in each ear), or between a hearing device and another device having an electrode (for example, an electrode of a scalp cap).

The electrode <NUM> may include an outer conductor <NUM> and an inner conductor <NUM>. In one manner of characterization, the outer conductor <NUM> is disposed closer to the external environment than the inner conductor <NUM>. The inner conductor <NUM> may be electrically coupled to the outer conductor <NUM>. The outer conductor <NUM> or the inner conductor <NUM> may form at least part of the outer surface <NUM> of the hearing device <NUM>. The outer conductor <NUM> or the inner conductor <NUM> may be disposed at least partially or entirely in the housing <NUM> or the body <NUM>.

One electrode <NUM> of the hearing device <NUM> may be the same size as or a different size than another electrode <NUM> of the same hearing device <NUM>. In some embodiments, the size of the electrode <NUM> or any of its components, such as the conductors <NUM>, <NUM>, may be specifically sized to be suitable for particular applications as described herein in more detail, particularly as a trade off to the spacing between electrodes.

The outer conductor <NUM> may be the same size as or a different size than the inner conductor <NUM>. The size of the conductors <NUM>, <NUM> may be defined in terms of outer surface area, total volume, conductivity/resistance, or other characteristics that may affect electrical coupling, particularly to the skin.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be disposed at least partially or entirely in the housing <NUM> or the body <NUM> of the hearing device <NUM>. The electrode <NUM> may be described as being superflush to the housing <NUM> when an outer portion of the electrode extends beyond the housing. The electrode <NUM> may be described as being flush to the housing <NUM> when the outer portion of the electrode extends about even with the housing. The electrode <NUM> may be described as being subflush to the housing <NUM> when an outer portion of the electrode is recessed in the housing <NUM>.

In some embodiments, to provide good electrical contact with acceptable surface fatigue, a superflush electrode <NUM> may protrude from the housing <NUM> to define a convex protrusion height less than or equal to about <NUM>, about <NUM>, about <NUM>, or about <NUM>. In some embodiments, a subflush electrode <NUM> may recess from the housing <NUM> to define a concave recess depth less than or equal to about <NUM>, about <NUM>, about <NUM>, or about <NUM>.

The outer conductor <NUM> or the inner conductor <NUM> may be described individually as being subflush, flush, or superflush to the outer surface <NUM>, the housing <NUM>, or the body <NUM>. For example, in some embodiments, the outer conductor <NUM> may be disposed superflush to the housing <NUM> and define at least part of the outer surface <NUM>, and the inner conductor <NUM> may be disposed subflush to the outer surface <NUM>. In other embodiments, the outer conductor <NUM> may be disposed subflush to the housing <NUM>. In still other embodiments, the outer conductor <NUM> may be disposed flush to the housing <NUM> and entirely disposed within the housing.

The body <NUM> may include a void <NUM> interior to the housing <NUM>. The void <NUM> may be defined at least partially by the housing <NUM>. One or more hearing device components <NUM> may be disposed at least partially or entirely in the void <NUM>. The acoustic transducer <NUM> may be disposed at least partially or entirely in the void <NUM>. The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be disposed at least partially or entirely in the void <NUM>.

The electrode <NUM> may be directly couplable to the skin of the user to provide good electrical coupling. In some embodiments, the electrode <NUM> may be flush or superflush to facilitate direct coupling to the skin. For example, the outer conductor <NUM> may be disposed at least partially in a cavity, which may be defined at least partially by a subflush inner conductor <NUM>. The outer conductor <NUM> may rest on an outer surface of the inner conductor <NUM>. Direct coupling may facilitate ease of use because, for example, an electrolytic liquid may not need to be added each time the user puts on the hearing device <NUM>.

In some embodiments, however, the electrode <NUM> or any of its components, such as the conductors <NUM>, <NUM>, may include or be formed at least partially of an electrolytic liquid. Although an electrolytic liquid may not be necessary, using the liquid may facilitate good electrical coupling and be suitable for at least some applications.

The electrode <NUM> may also be indirectly couplable to the skin of the user to provide good electrical coupling. Preferably, in some embodiments, the electrode <NUM> or any of its components, such as the conductors <NUM>, <NUM>, may be subflush to the housing <NUM> to form a cavity to hold an electrolytic liquid, which may be in the form of an electrolytic gel. A gel may hold its shape while retaining the electrolytic liquid. The formation of the cavity may facilitate retaining the electrolytic gel proximate or adjacent to the electrode <NUM> and may mitigate the uncomfortable feeling of liquid against the skin by restraining the liquid to a limited surface area.

The electrode <NUM> or any of its components, such as the conductors <NUM>, <NUM>, may be formed of any suitable conductive material. A suitable conductive material may be at least partially or entirely compressible (for example, soft) or at least partially or entirely incompressible (for example, hard). A compressible conductive material may provide a rebound force, which may facilitate electrical coupling. In some embodiments, an outer portion of the electrode <NUM>, such as the outer conductor <NUM>, may be formed of a compressible conductive material. A compressible conductive material used in an outer portion of the electrode <NUM> may facilitate comfort. An incompressible conductive material used in an outer portion of the electrode <NUM> may facilitate ease of manual handling and cleaning.

The electrode <NUM> may be at least partially solid or at least partially liquid. Non-limiting examples of suitable conductive material for conductors <NUM>, <NUM> of the electrode <NUM> include one or more of gold, stainless steel, aluminum, titanium, titanium nitride, silver, silver chloride, silver-silver chloride, graphene, and electrolytic liquid (for example, in the form of a gel). In some embodiments, preferably, a superflush electrode <NUM> may be made of gold or a composite material containing gold. In some embodiments, preferably, a subflush electrode <NUM> may be made of silver-silver chloride or a composite material containing one or more of silver and silver chloride. An electrolytic liquid may be disposed on the subflush electrode <NUM>. In some embodiments, the electrode <NUM> may include a material capable of absorbing an electrolytic liquid to provide electrical conduction. The material may be "recharged" using electrolytic liquid. Also, such an absorptive material may become more conductive in response to absorbing the user's own perspiration or ear wax.

In some embodiments, the electrode <NUM> may include solid outer and inner conductors <NUM>, <NUM>. An electrolytic liquid may be further disposed between the outer conductor <NUM> and the skin of the user. Preferably, in some embodiments, the electrode <NUM> does not include any liquid exposed to the skin of the user. In some embodiments, the electrode <NUM> may include a liquid outer conductor <NUM> and a solid inner conductor <NUM>. For example, the outer conductor <NUM> may be formed at least partially or entirely of a liquid (for example, an electrolytic gel) and the inner conductor <NUM> may be solid.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may include an elastomer. In some embodiments, a conductive material may be embedded or disposed in an elastomer to provide electrical conductivity through the thickness of the elastomer. The resulting material may be described as an elastomeric conductor or a conductive elastomer. The embedded conductive material may be powdered or chopped. Preferably, in some embodiments, the conductive material may be powdered and include one or more of silver, silver chloride, and silver-silver nitride. Preferably, in some embodiments, the conductive material may be chopped and include one or more of titanium and titanium nitride.

As used herein, "chopped" material may refer to coarse grains of material, for example, in the micrometer range, whereas "powdered" material may refer to fine grains of material, for example, in the nanometer range. For example, chopped material may be within range no less than about <NUM> micrometers, about <NUM> micrometers, or about <NUM> micrometer to no more than about <NUM> micrometers, about <NUM> micrometers, or about <NUM> micrometers.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may include printed conductive material. For example, conductive material may be printed on an insulating material or other conductive material. In some embodiments, conductive material may be printed on a surface of an insulating elastomer to form the outer conductor <NUM>. The inner conductor <NUM> may extend through an insulating elastomer of the housing <NUM> to electrically couple to a printed outer conductor <NUM>. In some embodiments, conductive material may be printed on a surface of the inner conductor <NUM>.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be integrally formed with at least a portion of the housing <NUM>. In some embodiments, the electrode <NUM> may include an elastomer integrally formed with an insulating elastomer of the housing <NUM>. For example, a portion of an elastomer may be embedded with conductive material to form the electrode <NUM> and remaining portions of the elastomer are not embedded with conductive material to form an insulating portion of the housing <NUM>. In some embodiments, the electrode <NUM> may be described as part of the housing <NUM>.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be formed by additive manufacturing processes. Non-limiting examples of additive manufacturing processes include one or more of 3D printing and electroplating. Non-limiting examples of 3D printing include one or more of cold-press sintering, direct metal laser sintering (DMLS), and fused deposition modeling (FDM). Preferably, in some embodiments, the electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be formed at least partially or entirely using 3D printing.

In some embodiments, the electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be formed by negative manufacturing processes, such as masked lithography. For example, the housing <NUM> may be formed and then a portion may be removed to make room for the electrode <NUM>.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be removably coupled to the housing <NUM>, body <NUM>, or other components of the electrode <NUM> (for example, including being removably disposed in a cavity of the housing). In some embodiments, the electrode <NUM> or any of its components, such as the conductors <NUM>, <NUM>, may be replaceable or disposable, for example, upon being worn out or soiled. Being removable may facilitate easy replacement of the electrode <NUM> or any of its components. For example, in some embodiments, the outer conductor <NUM> may be removably coupled to the inner conductor <NUM>, which may be removably or permanently coupled to the housing <NUM>. The outer conductor <NUM> may be easily replaceable.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may include a pellet including powdered conductive material. As used herein, a "pellet" refers to compacted or pressed material, such as powdered conductive material compacted together to form a generally cylindrical pellet or any other suitable shape that allows electrical conduction through the pellet.

The pellet may be formed using any suitable technique. In some embodiments, the pellet may be formed using sintering, which is a process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction. In some embodiments, the outer conductor <NUM> of the electrode <NUM> may include the textured axial surface of the pellet. For a pellet shaped like a cylinder, an axial surface of the pellet may be coarser or more textured than the radial surface of the pellet. Axial loading during the sintering process along the length of the cylindrical pellet may be lower (for example, in terms of pounds per square inch or psi) than the radial loading, which may result in a coarser axial surface compared to the radial surface of the pellet. Although both surfaces may appear to be smooth to the naked eye, the axial surface may be coarser or textured compared to the radial surface, for example, at the micrometer level.

In some embodiments, the outer surface of the electrode <NUM> may be described as smooth. The smooth outer surface may be formed of any suitable technique, such as sintering with high axial loading or any suitable plating process.

In general, particularly in the absence of an electrolytic gel, a textured outer surface of the electrode <NUM> may provide a better electrical interface to skin when compared to a smooth surface of the electrode. In some embodiments, an electrolytic gel may be disposed on the outer surface of the electrode <NUM> to facilitate electrical coupling to the skin, whether the outer surface is textured or smooth. For example, an electrolytic gel may facilitate electrical coupling between the outer surface of the outer conductor <NUM> of the electrode <NUM> and the user's skin.

The electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may have a microtextured, or micro-pitted, outer surface. As used herein, a "microtextured" or "micro-pitted" refers to a microfeature measuring in the micrometer range (for example, as low as about <NUM> micrometers, or as low as about <NUM> micrometer, to as high as about <NUM> micrometers, or as high as bout <NUM> micrometers) that is present at least partially or entirely across the surface. An outer surface with such microfeatures may facilitate good electrical coupling to the skin with a direct interface. The effectiveness of the microfeatures to may depend on, for example, parameters of the sintering process, such as axial loading, of the conductive material particles used to form the outer conductor <NUM> of the electrode <NUM>.

In some embodiments, an outer portion of the electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be formed using a plating process. The plated electrode <NUM> may be formed to match or almost match the outer contour of the housing <NUM>, which may be preferably convex. In some embodiments, compared to a cylindrical pellet, a contoured plated electrode <NUM> may provide a better fit and contact area with the ear of the user. The plated electrode <NUM> may be formed of any suitable material, such as an implant grade metal. In some embodiments, the plated electrode <NUM> includes gold or is formed of a composite material containing gold.

An outer portion of the electrode <NUM> or any of its components, such as conductors <NUM>, <NUM>, may be formed of one or more materials capable of withstanding exposure to the skin of the user and to the ambient environment on a regular basis. To provide a precise electrical measurement over an expected lifetime of the outer conductor <NUM> of the hearing device <NUM> (for example, without significant signal drift over time), such materials may be biocompatible and resistant to corrosion or degradation. Degradation may be caused by, for example, oxidation due to exposure to perspiration from the skin and earwax in the ear canal. Preferably, in some embodiments, an outer portion of the electrode <NUM>, such as the outer conductor <NUM>, may include one or more of silver-silver chloride and titanium nitride.

Hearing device components <NUM> may include one or more of the acoustic transducer <NUM> and the electrode <NUM>. The acoustic transducer <NUM> and the electrode <NUM> may be operatively coupled to other hearing device components <NUM> of the hearing device <NUM>. In some embodiments, the electrode <NUM> may be coupled using wire conductors. For example, the inner conductor <NUM> may include a wire conductor that is electrically coupled to the outer conductor <NUM>.

Hearing device components <NUM> may include a controller, which may carry out various functionality of the hearing device <NUM>, such as taking measurements with the electrodes. Measurements of electrical signals using the electrode <NUM> may be further processed in the hearing device <NUM> or may be transmitted using a communication interface (for example, an antenna) to other devices or equipment for further processing.

In addition to measuring, such as for BCI applications, the electrode <NUM> may be used for other functionality of the hearing device <NUM>. For example, the controller may be used to carry out hearing aid functionality, which may involve using the acoustic transducer <NUM>. As another example, the controller may be used for power savings of the hearing device <NUM>. When the controller detects a signal using the electrode <NUM>, the hearing device <NUM> may turn on. When the controller detects no signal using the electrode <NUM>, the hearing device <NUM> may turn off to conserve battery power.

One or more of the controllers described herein may include a circuit, a processor, such as a central processing unit (CPU), computer, logic array, or other device capable of directing data coming into or out of the hearing devices described herein. In some embodiments, the controller includes one or more computing devices having memory, processing, and communication hardware. The functions of the controller may be performed by hardware and/or as computer instructions on a non-transient computer readable storage medium.

The processor of the controller may include any one or more of a microprocessor, a controller, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or equivalent discrete or integrated logic circuitry. In some examples, the processor may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and/or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller or processor herein may be embodied as software, firmware, hardware, or any combination thereof. While described herein as a processor-based system, an alternative controller could utilize other components such as relays and timers to achieve the desired results, either alone or in combination with a microprocessor-based system.

In one or more embodiments, the exemplary systems, methods, and interfaces may be implemented using one or more computer programs using a computing apparatus, which may include one or more processors and/or memory. Program code and/or logic described herein may be applied to input data/information to perform functionality described herein and generate desired output data/information. The output data/information may be applied as an input to one or more other devices and/or methods as described herein or as would be applied in a known fashion. In view of the above, it will be readily apparent that the controller functionality as described herein may be implemented in any manner known to one skilled in the art.

<FIG> shows two hearing devices <NUM> each including a plurality of electrodes <NUM> formed at least partially or entirely as pellets having conductive material. In the illustrated embodiment, the hearing device <NUM> includes a body <NUM> having a housing <NUM>. Further, the electrodes <NUM> are disposed flush with the housing <NUM>. In particular, the outer conductors <NUM> are disposed in the housing <NUM> and flush with the housing <NUM>. The hearing devices <NUM> may be custom formed to fit in the ear canals of an individual.

The outer conductors <NUM> may be pellets formed of sintered conductive material or plated conductive material. The inner conductors <NUM> may include conductive wires electrically coupled to the outer conductors <NUM>, for example, by soldering. Acoustic transducers <NUM> may be disposed in the body <NUM> (for example, recessed) and directed outwardly toward apertures formed in the housing <NUM> to provide sound to the ear canal of the user.

In general, the surface area of the electrodes <NUM> may be made as large as possible relative to the overall size of the hearing device <NUM> to facilitate better electrical contact and a lower SNR. In some embodiments, the electrode <NUM> may cover the entire hearing device <NUM> or at least portions of the device meant to contact the skin of the user. Some devices <NUM> include two or more electrodes <NUM>. The use of two or more electrodes <NUM> may provide the ability to measure properties of electrical signals, for example, by detecting the delay between in electrical signals received at each electrode or by detecting the differential between electrodes. In general, the distance between the electrodes <NUM> may be made as large as possible relative to the size of the hearing device <NUM> to facilitate detecting the delay or differences between the signals. Furthermore, placement of the electrode or electrodes <NUM> may facilitate better measurements for certain applications. In some embodiments having two or more electrodes, one electrode <NUM> may be placed in the ear canal and another electrode may be placed outside of the ear canal, for example, behind the ear. In general, the electrodes <NUM> may be used for any application wherein measuring an electrical signal conducted through the skin may be beneficial.

In some embodiments, the electrodes <NUM> each may be sized to cover less than or equal to about all, about one half, about one fourth, about one eighth, or about one tenth of the outer surface of the respective hearing device <NUM>. In some embodiments, the electrodes <NUM> may be spaced greater than or equal to about one tenth, about one eighth, about one fourth, about one third, or about one half of a maximum dimension (for example, length) of the hearing device <NUM>.

<FIG> each show various hearing devices <NUM>, <NUM>, <NUM>, <NUM> having elastomeric conductors. Each of the hearing devices <NUM>, <NUM>, <NUM>, <NUM> may be custom formed to fit in the ear canal of a particular individual. In the illustrated embodiment, each of the electrodes <NUM>, <NUM>, <NUM>, <NUM> are disposed flush with the respective housing <NUM>, <NUM>, <NUM>, <NUM>. The electrodes <NUM>, <NUM>, <NUM>, <NUM> may be formed of conductive material embedded in an elastomer.

The electrodes <NUM>, <NUM>, <NUM>, <NUM> may be any suitable size to facilitate good electrical contact and the ability to measure a variety of electrical signals. For example, as shown, the electrode <NUM> may be sized to substantially cover at least about one half of the outer surface of the hearing device <NUM>. As another example, both of the two electrodes <NUM> together may be sized to substantially cover at least about one quarter of the outer surface of the hearing device <NUM> while being spaced at least one fourth of the maximum dimension (for example, length) of the hearing device. As a further example, electrode <NUM> and electrode <NUM> each may be sized to cover about at least one eighth of the outer surface of the respective hearing device <NUM>, <NUM>.

In some embodiments, to custom fit a hearing device for an individual's ear canal, the ear canal may be measured, for example, by a molding process. The hearing device, particularly the housing, may be made based on those measurements.

Any suitable technique to form a housing may be used. At least one non-limiting example of a technique to form a housing is described in <CIT>, entitled HEARING ASSISTANCE DEVICE. Various techniques for forming a housing including a conductor for an electrode are described further herein with respect to <FIG> and <FIG>.

<FIG> shows a cast shell <NUM> used in forming a housing of a hearing device. The cast shell <NUM> provided may have a thin outer wall <NUM>, a thick outer wall <NUM>, and an inner wall <NUM> between the thin and thick outer walls. The cast shell <NUM> may be formed by any suitable technique, such as injection molding or an additive manufacturing process. A cavity <NUM> may be disposed proximate to the thin outer wall <NUM>. The cavity <NUM> may be separated from a void <NUM> by the inner wall <NUM>. The void <NUM> may be proximate to the thick outer wall <NUM>. In some embodiments, the thin outer wall <NUM> may have a thickness that is less than or equal to about <NUM> mils, about <NUM> mils, about <NUM> mils, about <NUM> mils, about <NUM> mils, about <NUM> mils, or less.

An elastomeric conductor <NUM> may be formed in the cavity <NUM> of the cast shell <NUM>. The elastomeric conductor <NUM> may be formed of by any suitable technique, such as injection molding or an additive manufacturing process. In some embodiments, one or more elastomeric conductors <NUM> may be formed in one or more discrete subcavities, respectively, in the cavity <NUM>. Subcavities may be separated by additional walls of the cast shell <NUM> or may be defined by a difference in materials formed in the cavity. As shown, two discrete pieces of the elastomeric conductor <NUM> may be formed in the cavity <NUM>. Another elastomer may be formed in the remainder of the cavity <NUM>, such as an elastomeric conductor or an elastomeric insulator. Using subcavities may facilitate the formation of a small electrode or a plurality of electrodes on a single hearing device for various applications (see, for example, <FIG>). However, in some embodiments, one or more elastomeric conductors <NUM> may fill almost all or the entire cavity <NUM>.

The thin outer wall <NUM> may be removed from the remainder of the cast shell <NUM> to form an outer surface <NUM> defined at least partially by the thick outer wall <NUM> and the elastomer that was disposed in the cavity <NUM>, which may include the elastomeric conductor <NUM>. In some embodiments, the outer surface <NUM> may also be defined by an elastomeric insulator formed in the cavity <NUM>.

<FIG> shows a housing <NUM> including an electrode <NUM> (not comprised by the claims, for illustrative purpose only). The housing <NUM> may be formed by a shell <NUM> and a frame <NUM>. The shell <NUM> and the frame <NUM> may be formed separately. Although, in some embodiments, the shell <NUM> and the frame <NUM> may be formed integrally. In general, the frame <NUM> may be more rigid than the shell <NUM>. The shell <NUM> may be formed of a hard or a soft material. In some cases, a soft material may be more comfortable to place in the ear canal.

The frame <NUM> may be inserted into the shell <NUM>. One or more conductors may extend through the shell <NUM> to provide one or more electrodes <NUM>. In some embodiments, when the frame <NUM> includes an electrode <NUM> prior to insertion, the electrode may puncture through the shell <NUM> as the frame is inserted. The shell <NUM> may generally be formed of an electrically insulating material. The frame <NUM> may be formed of an electrically insulating material. However, the frame <NUM> may include one or more conductors to electrically couple to the electrode <NUM>.

One or more hearing device components (see <FIG>) may be disposed on the frame <NUM>. The hearing device components may enable various functionality of the hearing device. A non-limiting example of a hearing device component is a processor. The hearing device components may be operatively coupled to the electrode <NUM> to enable various functionality using the electrode.

The electrode <NUM> may be formed in any suitable manner. Non-limiting examples of forming the electrode <NUM> include one or more of embedding electrically conductive material in the material of the shell <NUM> and printing or otherwise disposing conductive material on the shell (for example, using 3D printing). In some embodiments, the electrode <NUM> may be formed with the frame <NUM>. For example, the electrode <NUM> and frame <NUM> may be formed by 3D printing. Inserting the shell <NUM> into the frame <NUM> may dispose at least part of the electrode <NUM> through the shell <NUM>. In some embodiments, the electrode <NUM> may be formed with the shell <NUM>. For example, the electrode <NUM> and the shell <NUM> may be formed by cast molding.

Thus, various embodiments of the ELECTRODES FOR HEARING DEVICES AND RELATED METHODS are disclosed. Although reference is made herein to the accompanying set of drawings that form part of this disclosure, one of at least ordinary skill in the art will appreciate that various adaptations and modifications of the embodiments described herein are within, or do not depart from, the scope of this disclosure. For example, aspects of the embodiments described herein may be combined in a variety of ways with each other. Therefore, it is to be understood that, within the scope of the appended claims, the claimed invention may be practiced other than as explicitly described herein.

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 in all instances 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.

The terms "coupled" or "connected" refer to elements being attached to each other either directly (in direct contact with each other) or indirectly (having one or more elements between and attaching the two elements).

Terms related to orientation, such as "interior," "external," and "end" are used to describe relative positions of components and are not meant to limit the orientation of the embodiments contemplated.

As used herein, "have," "having," "include," "including," "comprise," "comprising" or the like are used in their open-ended sense, and generally mean "including, but not limited to. " It will be understood that "consisting essentially of," "consisting of," and the like are subsumed in "comprising," and the like.

Claim 1:
A method of making a hearing device comprising a housing and an electrode configured to electrically couple to skin of a user, the method comprising:
providing a cast shell (<NUM>) comprising a thin outer wall (<NUM>), a thick outer wall (<NUM>), an inner wall (<NUM>) between the thin and thick outer walls, a cavity (<NUM>) proximate to the thin outer wall, and a void (<NUM>) proximate to the thick outer wall separated from the cavity by the inner wall;
forming an elastomeric conductor (<NUM>) in the cavity of the cast shell; and
removing the thin outer wall (<NUM>) to form the housing comprising an outer surface (<NUM>) defined at least partially by the thick outer wall (<NUM>) and the elastomeric conductor.