as) United States
`a2) Patent Application Publication 10) Pub. No.: US 2008/0205678 Al
` Boguslavskij et al. (43) Pub. Date: Aug. 28, 2008
`
`
`
`US 20080205678A1
`
`(54) HEARING APPARATUS WITH A SPECIAL
`ENERGY ACCEPTANCE SYSTEM AND
`CORRESPONDING METHOD
`
`(75)
`
`Inventors:
`
`Mihail Boguslavskij, Coburg (DE);
`ThomasHies, Singapore (SG);
`Kunibert Husung, Erlangen (DE)
`
`Correspondence Address:
`STEMENS CORPORATION
`INTELLECTUAL PROPERTY DEPARTMENT
`170 WOOD AVENUE SOUTH
`
`ISELIN, NJ 08830 (US)
`
`(73) Assignee:
`
`Siemens Audiologische Technik
`GmbH
`
`(21) Appl. No.:
`
`12/072,389
`
`(22)
`
`Filed:
`
`Feb. 26, 2008
`
`(30)
`
`Foreign Application Priority Data
`
`Feb. 26, 2007
`
`(DE) oe eee 10 2007 009 176.3
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(2006.01)
`HOAR 25/00
`(52) US. CMe coeccccccssssssssssssssssvseseesessessssasisssssenes 381/312
`
`(57)
`
`ABSTRACT
`
`Supplying energy into a hearing apparatus in order to charge
`its rechargeable battery is to be carried out by way of com-
`ponents, which take up as little space as possible. Compo-
`nents, which are mostly already present, are thus used for the
`energy supply. Energy is inductively injected into the coil of
`a receiver, into a data transmission coil or a telephonecoil for
`instance. Alternatively, acoustic energy can also be injected
`via the receiver or microphone and converted there into elec-
`trical energy. Special components need then not be provided
`for the energy supply process.
`
`(Stand der Fechnik )
`
` APPLE 1075
`
`1
`
`Apple v. GUI
`IPR2021-00471
`
`1
`
`APPLE 1075
`Apple v. GUI
`IPR2021-00471
`
`

`

`Patent Application Publication
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`Aug. 28,2008 Sheet 1 of 4
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`US 2008/0205678 Al
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`2,
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`FIG 1
`( Stand der Technik )
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`2
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`2
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`Patent Application Publication
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`Aug. 28,2008 Sheet 2 of 4
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`US 2008/0205678 Al
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`3
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`Patent Application Publication
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`Aug. 28,2008 Sheet 3 of 4
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`US 2008/0205678 Al
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`53
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` i)
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`+
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`FIG5
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`4
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`Patent Application Publication
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`Aug. 28,2008 Sheet 4 of 4
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`US 2008/0205678 Al
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`FIG6
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`5
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`US 2008/0205678 Al
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`Aug. 28, 2008
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`HEARING APPARATUS WITH A SPECIAL
`ENERGY ACCEPTANCE SYSTEM AND
`CORRESPONDING METHOD
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`[0001] This application claimspriority of German applica-
`tion No. 102007009176.3 DEfiled Feb. 26, 2007, which is
`incorporated by reference herein in its entirety.
`
`FIELD OF INVENTION
`
`[0002] The present invention relates to a hearing apparatus
`with a signal processing device, an energy storage device,
`which can be charged and which energizesthe signal process-
`ing device, and a converter device for converting an acoustic
`signal into an electrical signal or vice versaoralternatively a
`communication coil, for transmitting and/or receiving elec-
`tromagnetic control signals or data signals. Furthermore, the
`present
`invention relates to a corresponding method for
`charging an energy storage device ofa hearing apparatus. The
`term “hearing apparatus” is understood here to mean in par-
`ticular a device which can be worn on the head, aboveall a
`hearing device, a headset, earphones and suchlike.
`
`BACKGROUND OF INVENTION
`
`[0003] Hearing devices are portable hearing apparatuses
`which are used to supply the hard-of-hearing. To accommo-
`date the numerous individual requirements, different con-
`figurations of hearing devices such as behind-the-ear hearing
`devices (BTE), in-the-ear hearing devices (ITE), e.g. includ-
`ing conch hearing devices or channel hearing devices (CIC),
`are provided. The hearing devices designed by way of
`example are worn on the outer ear or in the auditory canal.
`Furthermore, bone conduction hearing aids, implantable or
`vibrotactile hearing aids are also available on the market. In
`such cases the damagedhearingis stimulated either mechani-
`cally or electrically.
`[0004] Essential componentsofthe hearing devices include
`in principle an input converter, an amplifier and an output
`converter. The input converter is generally a receiving trans-
`ducer, e.g. a microphone and/or an electromagneticreceiver,
`e.g. an induction coil. The output converteris mostly realized
`as an electroacoustic converter, e.g. a miniature loudspeaker,
`or as an electromechanical converter, e.g. a bone conduction
`receiver. The amplifier is usually integrated into a signal
`processing unit. This basic configuration is shown in the
`example in FIG. 1 of a behind-the-ear hearing device. One or
`a number of microphones 2 for recording the ambient sound
`are incorporated in a hearing device housing 1 to be worn
`behind the ear. A signal processing unit 3, which is similarly
`integrated into the hearing device housing 1, processes the
`microphonesignals and amplifies them. The output signal of
`the signal processing unit 3 is transmitted to a loudspeaker
`and/or receiver 4, which outputs an acoustic signal. The
`sound is optionally transmitted to the ear drum of the device
`wearer via a sound tube, whichis fixed with an otoplastic in
`the auditory canal. The power supply of the hearing device
`and in particular ofthe signal processing unit 3 is provided by
`abattery 5 whichis likewise integrated into the hearing device
`housing 1.
`[0005] Charging rechargeable batteries or batteries in a
`hearing device involves in many cases removing the recharge-
`able battery and/or battery from the hearing devices, plugging
`
`it into a charging device and charging it. After the charging
`process, the battery, which is generally very small and diffi-
`cult to manage, is removed from the charging device and
`reinserted into the hearing device. An alternative charging
`method consists in leaving the rechargeable battery in the
`hearing device and charging it there using a wired charging
`system. To this end, corresponding metallic contacts are to be
`provided on the hearing device. These contacts are disadvan-
`tageous in that they normally protrude from the housing and
`are not flush therewith. Consequently, they can be easily
`contaminated.
`
`[0006] The wireless transmission of energy to the hearing
`device is also known. The energy transfer for this can be
`carried out by meansofelectrical (capacitive), magnetic (in-
`ductive) and/or electromagneticfields. This type of charging
`process requires at least one additional component in the
`hearing device, which converts the corresponding field into
`electrical energy.
`[0007] An inductive method is used in most cases in order
`to wirelessly charge rechargeable batteries. The transmitter
`operates with a transmitting coil andthe receiver ofthe energy
`likewise uses a coil to accept the energy. Coils of this type are
`relatively large, which, with hearing devices in particular runs
`counter to the ongoing aim of miniaturizing hearing devices.
`[0008] The publication DE 199 15 846 C1 discloses an
`implantable system for rehabilitation of hearing loss. It com-
`prises a wireless telemetric device for transmitting data
`between an implantable part of the system and an external
`unit as well as a power supply arrangement. The implantable
`unit may contain an energy receiving circuit for providing
`recharging energy on the implant side.
`[0009] The publication DE 39 18 329 Al also discloses a
`hearing device for electrical stimulationofthe innerear.It has
`external signal processing electronics which is supplied from
`a power supply in order to convert microphonesignals into
`output signals which are suited to the inner ear stimulation.
`The signal processing electronics also wirelessly supplies a
`likewise implantable receiver circuit with operating energy.
`
`SUMMARY OF INVENTION
`
`[0010] The object of the present invention thus consists in
`being able to transmit energy to a hearing apparatus, without
`requiring a lot of installation space in the hearing apparatus
`for this.
`
`is achieved in accordance with the
`[0011] This object
`invention by a hearing apparatus with a signal processing
`device, an energy storage device, which can be charged and
`which supplies powerto the signal processing device, and a
`converter device for converting an acoustic signal into an
`electrical signal or vice versa, with a charging circuit being
`connected between the converter device and the energystor-
`age device so that energy, whichis transmitted acoustically or
`electromagnetically to the converter device, can be supplied
`electrically into the energy storage device by way of the
`charging circuit.
`[0012]
`Provision is also madein accordancewith the inven-
`tion for a method for charging an energy storage device of a
`hearing apparatus by transmitting acoustic energy to the hear-
`ing apparatus, converting the acoustic energy into electrical
`energy and supplying the electrical energy into the energy
`storage device.
`[0013]
`It is thus advantageously possible to also use an
`acousto-electric and/or electro-acoustic converter, which is
`generally already present in every hearing apparatus, for the
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`FIG. 1 shows a basic design of a hearing device
`[0024]
`energy supply. Thereis thus no need for a special component
`according to the priorart;
`for the energy supply, thereby reducing the overall volume of
`[0025]
`FIG. 2 shows a hearing device with an inductive
`the hearing apparatus.
`charging system accordingto the present invention;
`[0014] The converter device of the hearing apparatus
`[0026]
`FIG. 3 shows a hearing device with an acoustic
`according to the invention preferably includes a loudspeaker
`charging system accordingto the present invention;
`and/or receiver. The loudspeakerthus achieves the dual func-
`[0027]
`FIG. 4 showsa block diagram of a charging circuit
`tionality of outputting sound and accepting energy.
`for charging a battery by way ofareceiver;
`[0015] The converter device can however also include a
`[0028]
`FIG. 5 shows a block diagram of a hearing device
`microphone. The microphone which is usually already
`with an inductive charging device by meansof a receiver
`present in hearing devices can thus also be used for acousto-
`winding and
`electric energy conversion.
`[0029]
`FIG. 6 showsa diagram ofa receiver motor with a
`[0016] The converter device can be based on the electrody-
`charging coil.
`namic principle. The advantageofthis is that oscillations of a
`magnet produced by sound can be usedto induce a current.
`[0017] The converter device can however be based on a
`piezoelectric principle. According to this, piezoelectric
`microphonesor loudspeakers can also be used for the energy
`conversion.
`
`[0030] The exemplary embodiments illustrated in more
`detail below represent preferred embodiments ofthe present
`invention.
`
`DETAILED DESCRIPTION OF INVENTION
`
`For the electromagnetic injection of energy into the
`[0018]
`converter device, said device should havea plastic housing.
`This can ensure that the energy to be supplied can be injected
`in an almost unattenuated fashion.
`
`Ifthe hearing apparatus comprises a communication
`[0019]
`unit for wireless transmission to another hearing apparatus
`for instance, it is advantageousif the plastic housing of the
`converter device hasa first shielding against electromagnetic
`radiation abovea first limit frequency, which amounts to at
`least 15 kHz andin particular at least 500 kHz for instance.
`Radiation from the converter device can thus be shielded,
`which would interfere with a transceiver unit, which typically
`transmits at 120 kHz (old devices) or 3.3 MHz (new devices).
`[0020] The plastic housing can also have a secondshielding
`against electromagnetic radiation below a second limit fre-
`quency, which amountsat the most to 20 kHz andin particular
`at the most to 12 kHz. In such cases it is possible for the
`receiver to influence the audio bandbythe hearing apparatus
`receiving audio signals by way of a telephone coil for
`instance. A combined shielding with the first and second
`shielding is carried out if necessary so that a shielding gap is
`produced in an area in which the energy transmission is to
`take place.
`[0021]
`In accordance with a further embodiment, the hear-
`ing apparatus is realized as a hearing device with an external
`receiver, with the converter device including the external
`receiver. In this case, the receiver can be inserted into the
`charging stack of a charging device anda very efficient energy
`coupling can be ensured due to the small size of the receiver
`and/or the charging stack. A similar advantage is produced
`with small ITE and/or CIC devices.
`
`invention, a charging
`[0022] According to the present
`device with a sound generator for generating an acoustic
`energy transmission signal, with which an afore-described
`hearing apparatus can be supplied with energy, is also pro-
`posed. This charging device can comprise a coupling element
`for the acoustic coupling of the acoustic charging device to
`the hearing apparatus. In particular, a tube can be provided
`which transmits an acoustic energy transmission signal into
`the carrying hook of a behind-the-ear hearing device for
`instance.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0023] The present invention is now described in more
`detail with reference to the appended drawings, in which;
`
`FIG. 2 shows a behind-the-ear hearing device,
`[0031]
`which usually comprises a receiver 10, which is acoustically
`coupled to a carrying hook 12 by wayof a tubular coupling
`element 11, said carrying hook on its part conveying the
`output soundofthe receiver 10 to the ear ofthe hearing device
`wearer by way ofa receiver tube (not shown). The hearing
`device shown in FIG. 2 also has two microphones 13, 14, a
`communication coil 15 for data transmissionin particularto a
`second hearing device, a telephone coil 16, a battery 17 anda
`printed circuit board 18 with a conventional signal processing
`unit.
`
`[0032] An inductive charging device 19 is shown in FIG. 2
`physically separated from the hearing device. This inductive
`charging device 19 generates a magnetic alternating field.
`This magnetic alternating field allows numerous components
`of the hearing device to interact. If the receiver 10 operates
`according to the electrodynamic principle for instance,
`it
`comprisesan electrical coil, in which the magnetic alternating
`field can induce a current. This current can be used to charge
`the battery 17 with the aid of a charging circuit (compare FIG.
`4).
`Similarly, the microphones14, 15 can obtain energy
`[0033]
`from the magnetic alternating field, if they operate according
`to the electrodynamic principle and comprise corresponding
`coils. Further coils for accepting energy may be the commu-
`nication coil 15 as well as the telephone coil 16. In each case,
`a converter and/or a coil which is already present in the
`hearing device for another reason is used to obtain energy. A
`special coil for energy generation is thus not provided,
`although it could also be provided for instance as a loop
`antenna on the printed circuit board 18.
`[0034]
`In the exemplary embodimentin FIG.3, the same
`hearing device already shown in FIG. 2 is connected to an
`acoustic energy source 21 by way ofa tube 20. This generates
`a sound as an energy carrier, which propagates over the tube
`20 and the carrying hook 12 to the receiver 10. It is converted
`there into electrical energy. This can take place according to
`the electrodynamicprinciple or the piezoelectric principle for
`instance. Again, a suitable charging circuit (compare FIG.4)
`is used to charge the battery 16 with the aid of the obtained
`electrical signal. In principle, the microphones 13, 14 can also
`be supplied with acoustic energy from the acoustic energy
`source 21. They also convert the acoustic energyinto electri-
`cal energy in accordance with the respective principle.
`[0035]
`In the case of energy generation with the aid of the
`receiver 10, this is used as an electro-acoustic converter as
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`Aug. 28, 2008
`
`well as an acousto-electric converter in addition to its usual
`function. In the case of microphones 13, 14, the acousto-
`electric conversion principle is used for the energy genera-
`tion, which is also used for its usual application to pick-up
`sound.
`
`FIG. 4 shows a charging circuit by way of example,
`[0036]
`whichis used to charge a battery 30, if the energy is obtained
`by wayofthe receiver 31 for instance. The battery 30 usually
`energizes the amplifier 32 ofthe hearing device. In addition to
`this, it also energizes other switching components, suchasare
`shown in FIG.4 with the arrows 33. The output signal of the
`amplifier 32 is fed to the loudspeaker and/or receiver 31.
`[0037]
`In order to generate energy, the receiver 31 is oper-
`ated in reverse, which is why its connection is monitored by a
`detector 34. This determines a charging signal on the basis of
`a special signal sequencefor instance. Consequently,it inter-
`rupts the signal path between the amplifier 32 and the receiver
`31 with a switch 35 and conveysthe charging signal from the
`receiver 31 to a rectifier 36. The output signal oftherectifier
`36 is fed to a voltage regulator 37, which for its part charges
`the battery 30 with suitable voltage. A charging signal can be
`detected and tapped in this way from each converter. The
`components 34 to 37 ofthe charging circuit are either likewise
`already present in the hearing deviceor they only take up only
`relatively little space on the printed circuit board 18 for
`instance,if they are to be providedin addition.
`[0038] A further exemplary embodimentofa hearing appa-
`ratus according to the invention is shown in FIGS. 5 and6. In
`this embodimentFIG. 5 showsa block diagram of the essen-
`tial components of a hearing device as well as an inductive
`charging device. The hearing device hasa plurality of micro-
`phones 40, 41, ... , 4”. The microphones are used in each
`instance as an input unit for acoustic signals. A telephone coil
`42 is also provided as an input unit for the preprocessing unit
`42. The preprocessing unit 43 generally consists of a pream-
`plifier with an A/D converter and a voltage controller. The
`output signal of the preprocessing unit 43 is fed to a digital
`signal processor 44 with a clocked output stage. The digital
`signal processor 44 can be controlled by a program switch 45,
`a programmingsocket 46, a situation key 47 anda VCactua-
`tor 48. A rechargeable battery 49 energizes the preprocessing
`unit 43 andthe digital signal processor 44. The output signal
`of the digital signal processor 44is fed to a receiver 40. This
`has a plastic housing with or without special shielding. The
`receiver 50 operating according to the electrodynamic prin-
`ciple also has anelectric coil 51. It is not only used to convert
`the electrical signals from the signal processor 44 into corre-
`sponding magnetic fields, but also vice versa to convert
`inductively received signals into electrical signals. These
`inductive signals originate from a transmitting coil 52 of an
`inductive charging device 53. The energy transmitted by the
`charging coil 52 to the coil 51 ofthe receiver 50 is transmitted
`to a charging electronics 54 of the hearing device in the form
`of an electrical signal. It is changed there into a suitable form
`and fed into the battery 49.
`[0039] Alternatively, the microphones 40, 41, ..., 47 could
`also be usedfor energy transmission ifthey operate according
`to the electrodynamic principle. The charging coil 52 must
`then transfer the energy to the microphones 40 to 47 and the
`microphones 40 to 47 must be correspondingly connected to
`the charging electronics 54.
`[0040] The function of the hearing aid device is described
`in more detail below, into the receiver winding of which
`energy is inductively injected. As is known,a transformeris
`
`required for magnetic energy transmission. The primary
`winding is formed here by the charging and/or transmitting
`coil 52 of the charging device 53. The secondary windingis
`realized by the magnetic circuit of the receiver 50. A receiver
`housing which is usually made of metal is however trouble-
`somehere.It is typically used as a magnetic shielding of the
`receiver magnetic field and thusalso prevents the penetration
`of external magneticfields. If a receiver is however produced
`with a plastic housing,this is not only advantageousin terms
`of its cost-effective manufacture but also in terms of the
`inductive energy transmission which takes place unimpeded.
`In particular, a plastic receiver ofthis type can be used advan-
`tageously for hearing aid devices with an external receiver.
`[0041] A simple charging device 53 with a small bay for
`insertion of the acoustic converter can be used to provide
`energy. In the case of an externalreceiver, this is plugged into
`the bay. ITE and/or CIC devices can be introduced completely
`into a bay of this type for charging purposes. With BTE
`hearing devices, the receiver part or the microphone part
`(depending on which converter is used for the energy supply)
`is inserted into the bay.
`[0042]
`FIG. 6 showsthe principle of the inductive supply
`with the aid of a receiver motor and a charging coil. The
`plastic housing and the membrane of the receiver are not
`shown. The magnetic energy is injectedinto an air gap of the
`magnetic circuit 56 of the receiver motor by way of the
`charging coil 52, which is realized here as an air coil and
`showsthe primary coil. This magnetic circuit 56 generally
`consists of a laminated core 57, optionally with magnets (not
`shown) and a magnetic tongue 58 connected thereto. This is
`movedwith theaid of the coil 51 and moves a membrane (not
`shown)ofthe receiver 50. Field lines 59 indicate a magnetic
`field, which is injected into the air gap 55 and/or the magnetic
`circuit 56 by the charging coil 52. The corresponding mag-
`netic flux in the magnetic circuit 56 inducts an electric current
`in the coil 51, which is conveyed to the charging electronics
`54 by wayof the connecting leads 60.
`[0043]
`To ensure that the electrical energy can be injected
`into the receiver 50 in as lossless a manneras possible, said
`receiver has a plastic housing. This plastic housing can be
`provided with an electrical conductive layer,
`in order to
`ensure an electromagnetic shielding. Sensitive assemblies
`(transceivers for wireless data transmission between hearing
`devices and/or for receiving audio data for instance) in the
`hearing aid device are thus not disturbed.
`[0044]
`Inhearing systems with telephonecoils, a magnetic
`receiver shielding is essential for a data transmission to be at
`all possible in the audio range. It is thus necessary for instance
`to shield the receiverin the transmission range below 20 kHz
`so that audio data from the telephonecoil of the hearing aid
`device can be inductively received in the audio range in an
`interference-free fashion. If necessary, the limit frequency of
`this shielding can also lie below 20 kHz, e.g. at 12 kHz or 10
`kHz. The inductive energy transmission can then take place in
`a frequency range abovethis limit frequency, in other words
`above 12 kHz or 20 kHz, e.g. at 50 kHz, for instance.
`[0045]
`Ifa broadband data transmission is to be enabled
`between two hearing devices at 3.3 MHz in the hearing sys-
`tem, the receiver needs to be equipped with a corresponding
`HFshielding. The shielding then has a limit frequency of 500
`kHz for instance so that it can not be penetrated by radiation
`with a frequency lying thereabove and/or can only be pen-
`etrated by heavily attenuated radiation. This limit frequency
`can howeveralso be lower, for instance at 100 kHz or 15 kHz,
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`
`if a lower lying frequencyis used for the energy transmission.
`If necessary, this shielding can also be combined with the
`afore-mentioned shielding in the audio range so that a fre-
`quency clearance only exists only for the energy transmis-
`sion, in which frequency clearance effective energy can be
`transmittedto the receiver and/or the otherwise shielded con-
`
`verter. Standard BTEscanalso be realized with this charging
`technology by suitably adjusting the housing shielding.
`[0046] The inductive supply of energy into rechargeable
`batteries in hearing aid devices allows devices to be charged
`in a user-friendly fashion on a daily basis with a correspond-
`ing charging station. As no additional charging coil is needed
`on the secondary side in accordance with the invention, the
`corresponding devices can be built significantly smaller
`despite the use ofthis inductive charging technology.It is thus
`also possible to inductively charge even small ITE and CIC
`devices by using the dual function of the receiver and/or
`microphone.
`[0047]
`Some advantagesalso result in respect of the charg-
`ing devices, since they can be designedin a relatively simple
`fashion. They only have one charging bay for instance, into
`which the whole hearing device or only the external receiver
`of the hearing device is placed. In this process, the charging
`bay canberelatively independentof the hearing device hous-
`ing form.
`1.-12. (canceled)
`13. A hearing apparatus, comprising:
`a signal processing device;
`a chargeable energy storage device which that supplies
`powerto the signal processing device;
`a converter device that converts an acoustic signal into an
`electrical signal or vice versa; and
`a charging circuit connected between the converter device
`and the energy storage device such that energy, which is
`acoustically or electromagnetically transmitted to the
`converter device is electrically supplied to the energy
`storage device via the charging circuit.
`14. The hearing apparatus as claimed in claim 13, wherein
`the converter device includes a loudspeaker.
`15. The hearing apparatus as claimed in claim 13, wherein
`the converter device includes a microphone.
`
`16. The hearing apparatus as claimed in claim 13, wherein
`the converter device is being based on an electrodynamic
`principle.
`17. The hearing apparatus as claimed in claim 13, wherein
`the converter device is based on a piezoelectric principle.
`18. The hearing apparatus as claimed in claim 13, wherein
`the converter device comprising a plastic housing.
`19. The hearing apparatus as claimed in claim 18, wherein
`the plastic housing comprises a first shielding against elec-
`tromagnetic radiation abovea first limit frequency, whichis at
`least 15 kHz.
`
`20. The hearing apparatus as claimedin claim 19, wherein
`the first limit frequencyis at least 500 kHz.
`21. The hearing apparatus as claimedin claim 18, wherein
`the plastic housing comprises a secondshielding against elec-
`tromagnetic radiation below a secondlimit frequency, which
`is at the most to 20 kHz and in particular at the most to 12 kHz.
`22. The hearing apparatus as claimedin claim 21, wherein
`the secondlimit is at the most 12 kHz.
`
`23. The hearing apparatus as claimedin claim 19, wherein
`the plastic housing comprises a secondshielding against elec-
`tromagnetic radiation below a secondlimit frequency, which
`is at the most to 20 kHz and in particular at the most to 12 kHz.
`24. The hearing apparatus as claimedin claim 13, wherein
`includes with an external receiver and the converter device
`includes the externalreceiver.
`
`25. A charging device comprising:
`a sound generator for generating an acoustic energy trans-
`mission signal with which a chargeable energy storage
`device of an hearing apparatus is supplied with energy,
`26. The charging device as claimed in claim 25, includes a
`coupling element for the acoustic coupling of the charging
`device to the hearing apparatus.
`27. A method for charging an energy storage device of a
`hearing apparatus, comprising:
`transmitting acoustic energy to the hearing apparatus;
`converting the acoustic energy into electrical energy; and
`supplying the electrical energy to the energy storage
`device.
`
`9
`
`