Patent Description:
Near-Field Magnetic Induction (NFMI) communication utilizes a non-propagating magnetic field for communication between devices. A transmitter coil in one device modulates a magnetic field which is received and sensed by a receiver coil in another device.

NFMI communication systems differ from other types of wireless communication systems that use an antenna to generate and transmit an electromagnetic wave radiating outwardly into free space. The power density of the radiated electromagnetic wave decreases with distance to the antenna, namely proportional to the inverse of the distance to the second power (<NUM>/r<NUM>) or -<NUM> dB per decade, which facilitates long range communication.

NFMI communication systems have a short range (less than <NUM> meters).

The standard modulation schemes used in typical RF communications (amplitude modulation, phase modulation, and frequency modulation) can be used in NFMI communication systems.

NFMI communication systems are designed to contain transmission energy within the localized magnetic field. The magnetic field energy does not radiate into free space. The power density of nearfield transmissions decreases at a rate proportional to the inverse of the distance to the antenna to the sixth power (<NUM>/r<NUM>) or -<NUM> dB per decade.

In current commercial implementations of nearfield communications, the most commonly used carrier frequency is <NUM> and has a wavelength λ of <NUM> meters.

The NFMI field is transmitted through human tissue with very little absorption as opposed to RF electromagnetic waves, making NFMI communication systems suitable for communication between devices residing at opposite ears of a human.

<CIT> shows an induction loop for a hearing aid. The induction loop is made on/in a multi-layer PCB.

A hearing prosthesis is provided according to claim <NUM>.

The hearing prosthesis may be a hearing aid of any type that is configured to be head worn at an ear of a user of the hearing aid, such as a Behind-The-Ear (BTE), a Receiver-In-the-Ear (RIE), an In-The-Ear (ITE), an In-The-Canal (ITC), a Completely-In-the-Canal (CIC), etc., hearing aid.

The hearing prosthesis may be an implantable device, such as a cochlear implant (CI) with an electrode array implanted in the cochlea for electronic stimulation of the cochlear nerve that carries auditory sensory information from the cochlea to the brain. The hearing prosthesis is equipped with the near-field magnetic induction communication unit connected to the magnetic field antenna for local, i.e. short range, wireless communication that is not significantly attenuated by human tissue, e.g. between hearing prostheses worn on opposite sides of a head of a human, or between a unit of the hearing prosthesis worn on the outside of a head of a human and another unit of the hearing prosthesis implanted inside the head of the human.

The magnetic field antenna comprises a coil and a magnetic core, which is a ferrite core for provision of a strong magnetic field at low loss and low cost.

A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive traces, pads and other features etched from conductive sheets or layers, typically copper sheets, laminated onto a non-conductive substrate. Components, such as capacitors, resistors, active devices, etc., are generally soldered on the PCB.

PCBs can be single sided with one conductive layer, double sided with two conductive layers or multi-layer with outer and inner conductive layers. Conductive traces on different layers are connected with vias, i.e. through-hole paths going through one or more adjacent layers for electrically interconnecting different conductive layers. The vias are typically made conductive by electroplating, or are lined with tubes or rivets. Multi-layer PCBs allow for much higher component density.

Multi-layer printed circuit boards have trace layers inside the board. This is achieved by laminating a stack of materials in a press by applying pressure and heat for a period of time. This results in an inseparable one piece multi-layer PCB. For example, a four-layer PCB can be fabricated by starting from a two-sided copper-clad laminate, etch the circuitry on both sides, then laminate to the top and bottom pre-preg and copper foil. It is then drilled, plated, and etched again to get traces on top and bottom layers.

The ferrite core is embedded in the multi-layer printed circuit board whereby miniaturization is obtained at low cost.

Preferably, the coil includes conductive traces formed, e.g. by etching, in a conductive layer of the multi-layer printed circuit board for further ease of manufacture and reduction of cost.

Parts of conductive layers, e.g. forming ground planes, of the multi-layer printed circuit board may be used to provide magnetic shielding of electronic components such that the components are prevented from disturbing the magnetic field antenna. Shielding can be around other component or around the magnetic field antenna.

The near-field magnetic induction communication unit may also be embedded in the multi-layer printed circuit board facilitating further miniaturisation and cost reduction and ease of electrical interconnection of the near-field magnetic induction communication unit with the magnetic field antenna by conductive traces formed in conductive layers of the multi-layer printed circuit board.

The hearing loss processor may also be embedded in the multi-layer printed circuit board facilitating further miniaturisation and cost reduction and ease of electrical interconnection of the near-field magnetic induction communication unit with the hearing loss processor by conductive traces formed in conductive layers of the multi-layer printed circuit board.

The near-field magnetic induction communication unit may be configured for provision of the audio signal to the hearing loss processor.

The magnetic field antenna may be positioned in a housing of the hearing prosthesis so that, when the housing is worn at an ear of a user of the hearing prosthesis in its intended position during normal operation of the hearing prosthesis, a magnetic field generated by the magnetic field antenna is directed towards the other ear of the user of the hearing prosthesis.

The hearing prosthesis may be a cochlear implant with.

The hearing prosthesis may comprise one or more microphones, each of which converts an acoustic signal applied to the microphone into a corresponding analogue audio signal in which the instantaneous voltage of the audio signal varies continuously with the sound pressure of the acoustic signal at the microphone.

The hearing prosthesis may also comprise a telecoil that converts a varying magnetic field at the telecoil into a corresponding varying analogue audio signal in which the instantaneous voltage of the audio signal varies continuously with the varying magnetic field strength at the telecoil.

Typically, the analogue audio signal is made suitable for digital signal processing by conversion into a corresponding digital audio signal in an analogue-to-digital converter whereby the amplitude of the analogue audio signal is represented by a binary number. In this way, a discrete-time and discrete-amplitude digital audio signal in the form of a sequence of digital values represents the continuous-time and continuous-amplitude analogue audio signal.

Throughout the present disclosure, the "audio signal" may be used to identify any analogue or digital signal forming part of the signal path from the output of the one or more microphones, telecoil, or near-field magnetic induction communication unit to an input of the hearing loss processor.

Throughout the present disclosure, the "hearing loss compensated audio signal" may be used to identify any analogue or digital signal forming part of the signal path from the output of the hearing loss processor to an input of the output transducer.

The output transducer may be a receiver, an implanted electrode of a cochlear implant, etc., configured to output an auditory output signal based on the hearing loss compensated audio signal, wherein the auditory output signal can be received by the human auditory system, whereby the user hears the sound.

The near-field magnetic induction communication unit may be a circuit comprising both a wireless transmitter and a wireless receiver. The transmitter and receiver may share common circuitry and/or a single die or housing.

Alternatively, the transmitter and receiver may share no circuitry, and the near-field magnetic induction communication unit may comprise separate dies or housings with the transmitter and the receiver, respectively.

The hearing prosthesis may advantageously be incorporated into a binaural hearing prosthesis system, wherein two hearing prostheses are interconnected, e.g., through a wireless network, for digital exchange of data, such as audio signals, signal processing parameters, control data, such as identification of signal processing programs, etc., etc., and optionally interconnected with other devices, such as a remote control, etc..

Signal processing in the new hearing prosthesis may be performed by dedicated hardware or may be performed in one or more signal processors, or performed in a combination of dedicated hardware and one or more signal processors.

As used herein, the terms "processor", "signal processor", "controller", "system", etc., are intended to refer to CPU-related entities, either hardware, a combination of hardware and software, software, or software in execution.

For example, a "processor", "signal processor", "controller", "system", etc., may be, but is not limited to being, a process running on a processor, a processor, an object, an executable file, a thread of execution, and/or a program.

By way of illustration, the terms "processor", "signal processor", "controller", "system", etc., designate both an application running on a processor and a hardware processor. One or more "processors", "signal processors", "controllers", "systems" and the like, or any combination hereof, may reside within a process and/or thread of execution, and one or more "processors", "signal processors", "controllers", "systems", etc., or any combination hereof, may be localized on one hardware processor, possibly in combination with other hardware circuitry, and/or distributed between two or more hardware processors, possibly in combination with other hardware circuitry.

Also, a processor (or similar terms) may be any component or any combination of components that is capable of performing signal processing. For examples, the signal processor may be an ASIC processor, a FPGA processor, a general purpose processor, a microprocessor, a circuit component, or an integrated circuit.

In the following, the new hearing prosthesis is explained in more detail with reference to the drawings, wherein.

In the following, various examples of the new hearing prosthesis are illustrated. The new hearing prosthesis according to the appended claims may, however, be embodied in different forms and should not be construed as limited to the examples set forth herein.

It should be noted that the accompanying drawings are schematic and simplified for clarity, and they merely show details which are essential to the understanding of the new hearing prosthesis, while other details have been left out.

<FIG> schematically illustrates exemplary hearing prosthesis circuitry <NUM> of the new hearing prosthesis. The illustrated new hearing prosthesis is a hearing aid that may be of any suitable mechanical design, e.g. to be worn in the ear canal, or partly in the ear canal, behind the ear or in the concha, such as the well-known types: BTE, ITE, ITC, CIC, etc..

The illustrated hearing prosthesis circuitry <NUM> comprises a front microphone <NUM> and a rear microphone <NUM> for conversion of an acoustic sound signal from the surroundings into corresponding microphone audio signals <NUM>, <NUM> output by the microphones <NUM>, <NUM>. The microphone audio signals <NUM>, <NUM> are digitized in respective A/D converters <NUM>, <NUM> for conversion of the respective microphone audio signals <NUM>, <NUM> into respective digital microphone audio signals <NUM>, <NUM> that are optionally pre-filtered (pre-filters not shown) and combined in signal combiner <NUM>, for example for formation of a digital microphone audio signal <NUM> with directionality as is well-known in the art of hearing prostheses. The digital microphone audio signal <NUM> is input to the signal router <NUM> configured to output a weighted sum <NUM> of signals input to the signal router <NUM>. The signal router output <NUM> is input to a hearing loss processor <NUM> configured to generate a hearing loss compensated output signal <NUM> based on the signal router output <NUM>. The hearing loss compensated output signal <NUM> is input to a receiver <NUM> for conversion into acoustic sound for transmission towards an eardrum (not shown) of a user of the hearing aid.

The illustrated hearing prosthesis circuitry <NUM> is further configured to receive data, including control signals and digital audio from various transmitters, such as mobile phones, smartphones, desktop computers, tablets, laptops, radios, media players, companion microphones, broadcasting systems, such as in a public place, e.g. in a church, an auditorium, a theatre, a cinema, etc., public address systems, such as in a railway station, an airport, a shopping mall, etc., etc..

In the illustrated example, data including digital audio is transmitted wirelessly to the hearing prosthesis and received by the hearing prosthesis RF-antenna <NUM> connected to a RF-transceiver <NUM>. The RF-transceiver <NUM> retrieves the digital data <NUM> from the received RF-transceiver signal, including the digital audio representing a stereo audio signal or a mono audio signal. The signal router <NUM> is also configured to route the stereo channel (or the mono audio signal) intended for a hearing prosthesis at the other ear of the user to the near-field magnetic induction communication unit <NUM> that modulates the digital audio <NUM> of the stereo channel in question (or the mono audio signal) into a modulated signal suitable for transmission via the embedded ferrite antenna <NUM> that emits a local, non-propagating magnetic field in the direction of the other hearing prosthesis (not shown) with field lines aligned with a ferrite core of a ferrite antenna in a housing of the other hearing prosthesis for optimum, or substantially optimum, reception when both hearing prostheses are worn in their intended operational positions at the respective ears of the user during normal operation.

The other hearing prosthesis may have the same circuitry <NUM> as shown in <FIG>, wherein the ferrite antenna <NUM> receives the modulated magnetic field and converts it into a voltage that is output to the near-field magnetic induction communication unit <NUM> that is configured to demodulate the digital audio <NUM> of the stereo channel (or the mono audio signal) and forward it to the signal router <NUM> to include the digital audio <NUM> of the stereo channel (or the mono audio signal) in the audio signal <NUM> that is input to the hearing loss processor <NUM> for hearing loss compensation.

In this way, the digital audio <NUM> of the stereo channel (or the mono audio signal) for the other ear is transmitted to the hearing prosthesis at the other ear with little attenuation.

The digital audio <NUM> may include audio from a plurality of sources and thus, the digital audio <NUM> may form a plurality of input signals for the signal router <NUM>, one input signal for each source of audio.

In the event of receipt of digital audio by the RF-antenna <NUM>, the digital audio <NUM> may be transmitted to the user while the other signal <NUM> is attenuated during transmission of the digital audio. The other signal <NUM> may also be muted. The user may enter a command through a user interface of the hearing prosthesis of a type well-known in the art, controlling whether the other signal <NUM> is muted, attenuated, or remains unchanged.

<FIG> schematically illustrates an embedded magnetic field antenna <NUM> with an embedded ferrite core <NUM> The embedded magnetic field antenna <NUM> is included in a hearing prosthesis (not shown) for provision of local, i.e. short range, wireless communication that is not significantly attenuated by human tissue, e.g. between hearing prostheses worn on opposite sides of a head of a human, or between a unit of the hearing prosthesis worn on the outside of a head of a human and another unit of the hearing prosthesis implanted inside the head of the human. The illustrated magnetic field antenna <NUM> comprises a coil and a ferrite core <NUM> for provision of a strong magnetic field at low loss and low cost. The embedding of the ferrite core <NUM> in the multi-layer printed circuit board <NUM> leads to miniaturization at low cost.

The coil includes conductors formed by metallized through holes <NUM> and interconnected with conductive traces <NUM> formed in, e.g. by etching, conductive layers of the multi-layer printed circuit board for further ease of manufacture and reduction of cost.

<FIG> shows the antenna <NUM> from the side in a cross-section perpendicular to a plane of the multi-layer printed circuit board <NUM>, and along the length of the ferrite core <NUM>.

<FIG> shows a top view of the antenna <NUM>, wherein the line <NUM> indicates the position of the cross-section shown in <FIG> and the arrows <NUM> show the viewing direction of <FIG>.

<FIG> shows the antenna <NUM> in a cross-section perpendicular to the length of the ferrite core <NUM> along the line <NUM> shown in <FIG> in the viewing direction indicated by arrows <NUM>.

The ferrite core <NUM> is embedded in the multi-layer printed circuit board <NUM> in a way similar to the well-known embedding technology utilized for chip embedding with use of standard printed circuit board manufacturing processes.

In one example, the ferrite core <NUM> is initially applied and glued <NUM> to a core substrate <NUM>. Then a dielectric fill material <NUM>, e.g. a resin coated copper (RCC), is vacuum laminated on the core substrate <NUM> for void free distribution of the dielectric material <NUM>. Preferably, the resin formulation is adjusted so that its thermo-mechanical properties correspond to the thermo-mechanical properties of the ferrite core <NUM>. Then through holes <NUM> are made, e.g. by laser drilling, followed by copper metallization for formation of electrical connections between the two sides of the PCB having the ferrite core <NUM> between them. The metallized through holes <NUM> form part of the coil that winds around the ferrite core <NUM>. Finally, conductive trace lines <NUM> are formed of the copper coating of the two sides of the PCB opposite the ferrite core <NUM> for formation of the remaining parts of the coil that winds around the ferrite core and forms the antenna <NUM> together with the ferrite core <NUM>.

<FIG> schematically illustrates an embedded magnetic field antenna <NUM> operatively connected with an embedded near-field magnetic induction communication unit <NUM>. A stacked configuration is illustrated in <FIG> whereas the ferrite core <NUM> of the magnetic field antenna <NUM> and the near-field magnetic induction communication unit <NUM> are embedded in the same layer of the printed circuit board in <FIG>.

In <FIG>, the near-field magnetic induction communication unit <NUM> is also embedded in the multi-layer printed circuit board <NUM> facilitating further miniaturisation and cost reduction and ease of electrical interconnection of the near-field magnetic induction communication unit <NUM> with the magnetic field antenna <NUM> by through holes <NUM>, metallized micro-vias <NUM> connected to chip bond pads of the unit <NUM>, and conductive traces <NUM> formed in conductive layers of the multi-layer printed circuit board <NUM>.

The embedding of the near-field magnetic induction communication unit <NUM> and near-field magnetic induction communication unit <NUM> in the multi-layer printed circuit board <NUM> is realized with multiple bonding and lamination steps of the type disclosed above in connection with <FIG>.

In <FIG>, a conductive layer <NUM> forming a ground plane is provided in the multi-layer printed circuit board <NUM> to obtain magnetic shielding of electronic circuitry located above the magnetic shield <NUM> and opposite the magnetic field antenna <NUM> such that the circuitry is prevented from affecting the magnetic field antenna <NUM>.

<FIG> shows a hearing prosthesis <NUM> in the form of a Behind-The-Ear hearing aid <NUM> mounted in its intended operating position for normal use, i.e. with its BTE housing <NUM> mounted behind the ear, i.e. behind the pinna <NUM>, of the user. The BTE housing <NUM> of the illustrated Behind-The-Ear hearing aid <NUM> accommodates the hearing prosthesis circuitry <NUM> shown in <FIG>.

The illustrated Behind-The-Ear hearing aid <NUM> forms part of a binaural hearing prosthesis system with a similar second Behind-The-Ear hearing aid (not visible) mounted at the other ear (not visible) of the user.

The second Behind-The-Ear hearing aid (not visible) also comprises the hearing prosthesis circuitry <NUM> shown in <FIG>.

<FIG> also schematically illustrates a desktop computer <NUM> that is configured for wireless transmission <NUM> of data relating to a hardware and/or software configuration of the Behind-The-Ear hearing aid <NUM>, e.g. utilizing the Bluetooth LE protocol, to the Behind-The-Ear hearing aid <NUM> for adjustment of various parameters of the Behind-The-Ear hearing aid <NUM>.

Further, the desktop computer <NUM> is configured for wireless streaming of multi-channel audio, e.g. two-channel stereo, multi-channel surround sound, multi-channel teleconference audio, virtual reality 3D sound, etc., to the Behind-The-Ear hearing aid <NUM>.

The Behind-The-Ear hearing aid <NUM> is also configured to receive data, including control signals and digital audio from various other transmitters (not shown), such as mobile phones, smartphones, desktop computers, tablets, laptops, radios, media players, companion microphones, broadcasting systems, such as in a public place, e.g. in a church, an auditorium, a theatre, a cinema, etc., public address systems, such as in a railway station, an airport, a shopping mall, etc., etc..

In <FIG>, data, including digital audio, that are transmitted wirelessly <NUM> to the Behind-The-Ear hearing aid <NUM> are received by the Behind-The-Ear hearing aid RF-antenna <NUM>, see <FIG>, connected to a RF-transceiver <NUM>, see <FIG>,. The RF-transceiver <NUM>, see <FIG>, retrieves the digital data <NUM>, see <FIG>, from the received RF-transceiver signal, including the digital audio, e.g., representing a stereo audio signal, or a mono audio signal. The signal router <NUM>, see <FIG>, is also configured to route the stereo channel or mono audio signal intended for the second Behind-The-Ear hearing aid mounted at the other ear of the user to the near-field magnetic induction communication unit <NUM>, see <FIG>, that modulates the digital audio <NUM>, see <FIG>, of the stereo channel in question (or the mono audio signal) into a modulated signal suitable for transmission via the embedded ferrite antenna <NUM>, see <FIG>, that emits a local, non-propagating magnetic field in the direction of the second Behind-The-Ear hearing aid (not visible) with field lines aligned with a ferrite core of a ferrite antenna in a housing of the second Behind-The-Ear hearing aid for optimum, or substantially optimum, reception when both hearing aids are worn in their intended operational positions at the respective ears of the user during normal operation.

The dotted circle <NUM> indicates the orientation of the coil having windings around the ferrite core (not visible) of the embedded ferrite antenna (not visible). The orientation of the coil is substantially perpendicular to the longitudinal extension or direction of the ferrite core which is aligned with the ferrite core of the ferrite antenna in the housing of the second Behind-The-Hearing aid (not visible) for optimum, or substantially optimum, reception.

In the second Behind-The-Hearing aid (not visible) with the circuitry <NUM> shown in <FIG>, the ferrite antenna of the second Behind-The-Hearing aid receives the modulated magnetic field and converts it into a voltage that is output to the near-field magnetic induction communication unit that is configured to demodulate the digital audio of the stereo channel (or the mono audio signal) and forward it to the signal router to include the digital audio of the stereo channel (or the mono audio signal) in the audio signal that is input to the hearing loss processor for hearing loss compensation.

In this way, the digital audio of the stereo channel (or the mono audio signal) for the other ear is transmitted to the second Behind-The-Ear hearing aid at the other ear with little attenuation.

As already mentioned, the digital audio may include audio from a plurality of sources and thus, the digital audio may form a plurality of input signals for the signal router, one input signal for each source of audio.

In the event of receipt of digital audio by the RF-antenna, the digital audio may be transmitted to the user while other audio signals are attenuated during transmission of the digital audio. The other signals may also be muted. The user may enter a command through a user interface of the Behind-The-Ear hearing aid of a type well-known in the art, controlling whether the other signal is muted, attenuated, or remains unchanged.

<FIG> shows a hearing prosthesis <NUM> in the form of a cochlear implant <NUM> with a Behind-The-Ear housing <NUM> accommodating the hearing prosthesis circuitry similar to the hearing prosthesis circuitry <NUM> shown in <FIG> apart from the fact that the receiver <NUM> in <FIG> has been substituted by signal lines in the cable <NUM> that transmit the hearing loss compensated output signal <NUM>, see <FIG>, to a transmitter housing <NUM>.

The transmitter housing <NUM> is intended to be attached to the head (not shown) of a user and accommodates a near-field magnetic induction communication unit (not visible) that modulates the received hearing loss compensated output signal into a modulated signal suitable for transmission via an embedded ferrite antenna (not visible) that emits a local, non-propagating magnetic field in the direction of a receiver housing (not shown) with field lines aligned for optimum transmission and reception, respectively, with a ferrite core of a ferrite antenna in the receiver housing (not shown) that is implanted underneath the skin opposite the transmitter housing <NUM> when the transmitter housing <NUM> is attached to the head of the user. The receiver housing (not shown) provides the received and converted hearing loss compensated audio signal to an electrode (not shown) that is implanted in the cochlea (not shown) of the user.

The magnetic field antenna comprises a coil and a ferrite core for provision of a strong magnetic field at low loss and low cost. The ferrite core is embedded in a multi-layer printed circuit board whereby miniaturization is obtained at low cost.

The coil includes conductive traces formed, e.g. by etching, in a conductive layer of the multi-layer printed circuit board for further ease of manufacture and reduction of cost. The dotted circle <NUM> indicates the orientation of the coil having windings around the ferrite core (not visible) of the embedded ferrite antenna (not visible). The orientation of the coil is substantially perpendicular to the longitudinal extension or direction of the ferrite core aligned with the ferrite core of the ferrite antenna in the receiver housing (not shown) implanted inside the head of the human for optimum, or substantially optimum, reception of the transmitted signal.

Parts of conductive layers of the multi-layer printed circuit board may be used to provide magnetic shielding of electronic components such that the components are prevented from disturbing the magnetic field antenna. Shielding can be around other component or around the magnetic field antenna.

Claim 1:
A hearing prosthesis comprising an electric circuit (<NUM>) with a hearing loss processor (<NUM>) configured to process an audio signal (<NUM>) and compensate a hearing I1oss of a user of the hearing prosthesis and output a hearing loss compensated audio signal (<NUM>) based on the audio signal (<NUM>),
an output transducer (<NUM>) configured to convert the hearing loss compensated audio signal (<NUM>) into an auditory output signal that can be received by the human auditory system and resulting in the user hearing sound, and
a near-field magnetic induction communication unit (<NUM>) configured for wireless communication, and
a magnetic field antenna (<NUM>) operatively connected with the near-field magnetic induction communication unit (<NUM>), wherein the magnetic field antenna (<NUM>) comprises a coil,
and wherein at least a part of the magnetic field antenna is embedded in a multi-layer printed circuit board (<NUM>),
characterized in that
the magnetic field antenna (<NUM>) comprises a ferrite core (<NUM>), and
the coil includes conductive traces (<NUM>) formed in a conductive layer of the multi-layer printed circuit board (<NUM>).