Background of the invention Several ITE (in-the-ear) and CIC (completely-in-the-canal) hearing prostheses are known in the art.

A common feature of the above-mentioned prior art hearing prostheses is a quite compact structure, since these hearing prostheses often are intended for being completely inserted into an auditory canal of a user.

This fact leads to at least three significant problems to be dealt with in order to commercialize the product.

A first problem is that the hearing prosthesis needs to be adapted for insertion and retraction into and from the auditory canal. In order to comply with this requirement, necessary components of the hearing prosthesis such as transducers, battery, user interface means, etc. must be able to fit inside a very limited interior space of the auditory canal of the user.

A further problem is associated with a user interface of the hearing prosthesis, by means of which the use is able to control functions of the hearing prosthesis, such as a volume control, on-/off switch, program selector, etc. This is of course quite difficult due to the fact that the ITE prosthesis by nature is hardly accessible when inserted into the auditory canal of a user.

A further problem is that the hearing prosthesis due to its limited size is quite difficult to position correctly in the outer ear or ear canal and therefore candidates to mal-positioning. This problem is particularly pronounced for elderly hearing prosthesis users. The mal-positioning may result in that the hearing prosthesis may actually not be fixated as well as in a deteriorated acoustical performance caused by annoying feedback and/or erroneous insertion gain performance due to an undesired acoustical leak.

A yet further problem of the prior art ITE or CIC prosthesis is that it's compact dimensions inherently lead to a short physical distance between the loudspeaker and the microphone, thereby making the prosthesis prone to feedback problems.

A yet further problem of the prior art ITE or CIC prosthesis is that the prosthesis often is quite uncomfortable to wear due the mechanical structure and the materials typically chosen.

It is an object of the invention to provide a hearing prosthesis suffering of few or none of the above-mentioned problems.

Summary of the invention The invention relates to an in-the-ear hearing prosthesis comprising at least one loudspeaker arrangement and at least one microphone arrangement acoustically communicating with at least one sound input portion, said hearing prosthesis comprising a first portion by means of which the hearing prosthesis may be fixated in at least a part of an ear canal and said hearing prosthesis comprising at least one projection connected to said first portion, said projection being suspended so as to be located at least partly outside the concha when the hearing prosthesis is positioned in an ear.

According to a preferred embodiment of the invention, the projection may serve as support for a user interface such as user operated buttons, switches or volume control, and may as well serve as a grip to be used by the user when inserting and retracting the prosthesis into and from the auditory canal thus facilitating these operations.

According to. the invention the projection may have an overall length in the rage of 5 to 40 mm (from the rear edge to the front edge of the projection) such as between 10 and 30 mm or even more preferred between 15 and 25 mm. The thickness of the projection is preferably between 2 and 8 mm, preferably between 3 mm and 6 mm.

The user interface means is preferably arranged on the rear part of the projection.

In an embodiment of the invention, the at least one microphone arrangement is acoustically communicating with said at least one sound input portion, and the at least one sound input portion is preferably comprised in said at least one projection The sound input portion is preferably fixed with respect to the first portion, so as to fixate a predetermined orientation of the input portion relative to the first portion of the hearing prosthesis. In other words, the sound input portion is preferably locked relatively to the first portion at a certain position and a certain direction once the first portion and thereby the hearing prosthesis as such is fixated in the ear.

According to a preferred embodiment of the invention, the input portion has been orientated relatively remote to the loudspeaker arrangement, thereby reducing the possibility of the annoying feed-back of sound from the loudspeaker to the microphone.

Preferably, the projection should be suspended in the first portion.

In an embodiment of the invention, the sound input portion is located proximate to an outer end of said projection.

In an embodiment of the invention, the sound input portion is located in the outer end of said projection and outside of a user's concha once the hearing prosthesis is positioned in the user's ear.

The sound input portion preferably projects between 2 to 20 mm outside of the concha, even more preferably between 3 to 10 mm.

In an embodiment of the invention, the first portion comprises a fixture adapted for attachment of an ear-plug. The fixture allows the hearing prosthesis to be provided with anyone of a set of differently sized and/or shaped ear-plugs. By providing a set of different ear-plugs, a single hearing prosthesis design may be adapted to fit a large variety of user ear canal sizes and shapes. The user may additionally, e. g. during the fitting session, choose a suitable and comfortable ear-plug that fits hers/his needs for acoustical damping and/or comfort in an optimal manner.

In a particularly preferred embodiment of the invention, the ear-plug is made user exchangeable by manufacturing the ear-plug in a soft elastomeric material such as silicone with dimensions that provides a suitable attachment or pull-off force between the fixture and the ear-plug.

This detachable property of the ear-plug provides convenient and hazard-free maintenance of the hearing prosthesis. The ear-plug may additionally be replaced with a new similar or even different one at regular time intervals such as every week or month based on the requirements of the user.

In an embodiment of the invention, the sound input portion comprises at least one acoustic opening or sound channel between the exterior of the hearing prosthesis and a microphone port placed in the interior of the hearing prosthesis, thus allowing the sound input portion to communicate acoustically with said at least one microphone arrangement via at least one acoustical channel.

In a preferred embodiment of the invention, the projection forms a gripping arrangement by means of which the user may insert or remove the hearing prosthesis from the ear.

In an embodiment of the invention, the microphone arrangement is positioned within said projection.

In an embodiment of the invention, the projection may comprise a directional microphone arrangement, which comprises a pair of omni-directional microphones or a directional microphone or a combination of an omni-directional microphone and a directional microphone.

According to the invention, the ear-plug may be selected from a set of different "mushrooms"adapted for fitting into relatively few main structures of auditory canals.

It should be appreciated that the combination of a loudspeaker which may be situated within the user's auditory canal, and the relatively remote position of the microphone suppresses or minimizes feed-back. Thereby, a reduced sensitivity to feed-back resulting from acoustic leakage is obtained.

In an embodiment of the invention, the projection comprises a user interface means such as a push button or a switch that allows the user to turn the hearing prosthesis on or off or change between different preset listening programs.

In an embodiment of the invention, a distance between the input portion of the projection and the loudspeaker arrangement is 20 to 35 mm, preferably 22 to 28 mm.

In an embodiment of the invention, the projection is an integral part of a housing of the hearing prosthesis. The housing preferably comprises most electronic circuitry of the hearing prosthesis.

In a preferred embodiment of the invention, the housing is completely sealed against the external environment to form a barrier against dust, fluid, smoke particles, etc., which sealing significantly improves the reliability and life-time of the hearing prosthesis. According to this embodiment of the invention, the hearing prosthesis may further comprise a rechargeable battery, which is connectable to an associated battery charger through a set of electrical terminals located on an external part of the housing. Alternatively, a contactless charging arrangement may be utilized such as an inductively connected charger.

The battery is of a rechargeable type such as NiCad, NiMH or Li-Ion rechargeable button cell or flat-cell. According to a preferred embodiment of the invention, the rechargeable battery has a nominal capacity of about 20 mAh such as between 15-25 mAh. Other embodiment of the invention may utilize a single or several rechargeable battery cells such as substantially circular button cells. Each of these cells may have a capacity between 10 and 100 mAh, preferably between 15-40 mAh.

Alternatively, the hearing prosthesis may be provided with a traditional battery chamber for a non-rechargeable battery such as a Zinc-Air button cell.

The rechargeable battery is however particularly advantageous due to the fact that such battery allows the interior of the hearing prosthesis housing or at least the projection to be completely sealed off from for example external humidity.

Moreover, the easy handling of the ITE prosthesis according to the invention offers the users an advantageous recharging procedure, without the need of dedicated removal or insertion tools.

The rechargeable battery may be recharged by means of galvanic connected recharging means such as two electrical terminals or for example by a contactless arrangement such as an inductively connected charger.

In an embodiment of the invention, the projection comprises electronic data processing circuitry such as a hard-wired or programmable Digital Signal Processor, A/D converters, D/A converters and preamplifiers.

According to a preferred embodiment of the invention, all electronic components, including the microphone, are situated inside the projection of the prosthesis.

In other words, the electronic components form part of an external and visible part of the device.

In an embodiment of the invention, the first portion comprises an-at least partly- sealed off compartment or chamber within which a loudspeaker is arranged.

According to a preferred embodiment of the invention, the hearing prosthesis comprises two sealed chambers which both are sealed off against the external environment and against each other. The loudspeaker or receiver is placed in its own sealed off receiver chamber in the first portion and the receiver chamber is preferably placed adjacent to the projection that encloses the electronic components in the sealed chamber as previously mentioned. Fig. 1 shows in more detail such an embodiment of the invention. Electrical leads, which carry receiver drive signals, such as litze-wires between the receiver and the electronic components in the

projection are conveyed through a small hole in a wall between the two adjacent chambers. After the assembly procedure, the small hole is closed with a small rubber member or a drop of glue.

In an embodiment of the invention, the ear-plug comprises an individually molded plug. In a further embodiment of the invention, the ear-plug comprises a flexible or compressible"mushroom"of soft elastomeric material such as silicone or natural rubber or foam capable of fitting a variety of different user ear canal shapes and sizes.

In an embodiment of the invention, said ear-plug comprises silicone rubber having a Shore hardness value between 20 and 70, preferably between 40 and 50, more preferably between 40 and 55 and even more preferably between 20 and 30. The ear- plug may comprise a compressible foam portion or be completely made from an ear- canal shaped piece of foam. A foam ear-plug or ear tip preferably comprises a piece of open-cell slow-recovery foam adapted to contact the user's ear canal and at least partly to seal-off the ear canal when recovered. The foam piece preferably has recovery time between 2 and 20 seconds, more preferably between 4 and 15 seconds such as between 5 and 10 seconds. The foam ear-plug or ear tip may comprise a centrally positioned acoustical channel made in plastic to support the structure and to prevent the foam piece from being compressed to an extent that would close the acoustical channel.

The ear-plugs preferably have a largest uncompressed diameter of from 5 mm to 20 mm, preferably from 8 to 15 mm.

In an embodiment of the invention, the sound input portion comprises at least two spaced-apart acoustic openings from the surface of the hearing prosthesis housing and two microphone inlet ports placed in the interior of the hearing prosthesis.

According to a preferred embodiment of the invention, a directional microphone characteristic is obtained by applying spatial filtering or beam-forming to a pair of omni-directional microphone signals. It is possible to take advantage of the projection, which may support a distance between inlet ports of the microphones, which is impossible to accommodate in prior art ITE/ITC/CIC type of hearing prostheses.

A preferred distance between the microphone inlet ports (or acoustical openings) is from 5 to 20 mm, preferably between 10 and 15 mm.

In an embodiment of the invention, the sound input portion comprises at least one of the two acoustic openings arranged in the part of the projection located outside the concha once the hearing prosthesis is positioned in an ear.

In an embodiment of the invention, the loudspeaker arrangement is arranged within said first portion. Preferably, thereby facilitating that the loudspeaker arrangement is positioned within the users auditory canal, when the prosthesis is positioned in the users ear.

Brief description of the drawings A preferred embodiment of the present invention will now for illustration be described with reference to the enclosed figures, of which Fig. 1 illustrates a preferred embodiment of the invention as seen from above, Fig. 2 illustrates the electronic principle elements of a hearing prosthesis according to an embodiment of the invention, Fig. 3a illustrates a perspective view of the preferred hearing prosthesis,

Fig. 3b illustrates an exploded view of the preferred hearing prosthesis of Fig. 3a, Figs. 4a and 4b illustrate a hearing prosthesis according to the invention when positioned in an ear, and Figs. 5a and 5b illustrate different embodiments of a prosthesis according to the invention.

Detailed description Fig. 1 illustrates a preferred embodiment of the invention as seen from above.

The illustrated hearing prosthesis 1 comprises two main parts, a first portion 9 adapted for fitting and fixation into an ear, and a projection portion 2.

The first portion 9 is adapted for receiving and fixing a soft silicone mushroom 8 on a dent on the first portion 9 or receiver housing. The mushroom or ear tip 8 may be permanently fitted to the first portion 9, or it may preferably be exchangeable.

The mushroom 8 is designed to fit into the auditory canal of a user of the prosthesis 1. The first portion 9 moreover serves as a chamber or housing for a loudspeaker 20 (on Fig. 2).

As indicated by dotted lines, the projection 2 serves as a housing for most of the electronic hardware of the illustrated prosthesis 1. The indicated components are a battery, preferably a rechargeable battery 3, a DSP (Digital Signal Processing) based signal processing unit or module 4, a microphone 6 and an acoustic opening 7.

The function of the acoustic port or opening 7 in the projection 2 is to direct sound signals from an external sound field into a sound inlet port of microphone 6.

The projection, which is partly applied to obtain an advantageous positioning of the microphone 6, when the prosthesis is in its operational position, i. e. positioned in the ear of a user, may also serve as a foundation of an easy accessible user interface. The user interface may e. g. comprise control knobs, push buttons or other switches (not shown).

Finally, the illustrated prosthesis comprises a wired programming interface 5, which additionally is adapted for recharging of the rechargeable battery 3 and for additionally serving as programming interface to a host system such as a hearing prosthesis fitting system.

Fig. 2 illustrates the principal hardware components of the prosthesis 1 comprising a microphone 6 electrically coupled to a signal processing unit 4.

The signal processing unit 4 is again electrically connected to a receiver or loudspeaker 20.

A rechargeable NiMH battery 3 is connected to the signal processing unit 4 for supply of power and comprises a terminal 5 adapted for connecting to a charger (not shown) and moreover to serve as a programming interface.

It is preferred to apply rechargeable batteries having a nominal output voltage of about 1.2 Volt and thereby are able to deliver the required power supply voltage to all the electronic components without need to include DC/DC converting circuits.

The microphone 6 converts sound into electrical signals, which are fed to the signal processing unit 4. The illustrated signal processing unit 4 comprises on-board or integral A/D-and D/A-converters and preamplifiers adapted for interfacing the input signals to a digital signal processor of the signal processing unit 4 and again for conveying processed signals to the loudspeaker 20.

Evidently, the above description is for explanatory purposes, and the hardware components and the design may vary significantly within the scope of the invention.

Fig. 3a illustrates a perspective view of a hearing prosthesis 1 according to the invention. The illustrated prosthesis 1 corresponds to the one illustrated in Fig. 1.

The illustrated prosthesis 1 comprises a first portion 9 fitted with a soft silicone mushroom or ear-plug 8 and a projection 2. The microphone opening (s) at the end of the projection 2 are not shown on this figure.

Fig. 3b shows an exploded view of the hearing prosthesis 1 of Fig. 3a.

The prosthesis comprises a first projection, incorporating the main electronic components as described with reference to Fig. 2 except from the loudspeaker 20.

The loudspeaker 20 is here suspended within a receiver housing formed by an elliptical cup-shaped part of the projection 2 and the first end 32 by means of vibration isolating and shock absorbing means in the form of a semi-circular soft silicone member 31. An O-ring (not shown) is additionally mounted around the sound outlet of the loudspeaker 20 to secure a tight acoustical seal between the sound outlet of the loudspeaker 20 and the interior of the receiver housing.

The soft silicone mushroom 8 is preferably provided with a wax guard or filter (not shown) positioned inside it's sound channel that directs sound waves from an outlet port of the loudspeaker chamber 32 into the user's ear canal under operation. Since the user will exchange a worn-out mushroom 8 for a new one at regular time intervals, such as every week or month, wax clogging of the sound channel is effectively prohibited. The wax guard may comprise a substantially acoustical transparent piece of hydrophobic cloth or a mesh fabricated in a metallic or

thermoplastic material. Alternatively, the wax guard may be provided as an integral part of the mushroom or ear tip 8 by means of an injection molding process.

According to that embodiment of the invention, the wax filter may be formed as a perforated membrane located across the central sound channel of the ear tip.

Fig. 4a and 4b illustrates a side view and a slightly angled front view of a hearing prosthesis 1 according to a preferred embodiment of the invention when positioned in an ear 40.

As illustrated the prosthesis 1 is positioned with a first portion 9 inserted into the auditory canal of a user and with the projection 2 orientated forwardly and partly outside the concha of the user's ear.

It may be appreciated that the ITE hearing prosthesis 1 according to the present embodiment of the invention is conveniently operable for users and moreover, the orientation of the microphone outside the concha facilitates an advantageous input location for pick-up of incoming acoustic signals.

Fig. 5a and 5b illustrate different designs of the hearing prosthesis applicable within the scope of the invention.

The illustrated embodiment comprises a first portion 9, which preferably comprises an exchangeable ear-plug made from soft silicone or compressible foam or any other material with good acoustical damping and comfortable fit in the ear canal.

In Fig. 5a, a variation of the previously shown designs is illustrated. A projection 2 may comprise the main internal hardware components (not shown).

In Fig. 5b, another embodiment of the invention is applied, now incorporating most internal electronic components and a rechargeable battery within the first portion 9 or

near to the first portion, thereby facilitating a more slim design of the projection 2, reaching from the first portion and forward, when positioned in an ear.

In both the above described designs, the microphone is preferably arranged at the end portion of the projection 2, i. e. as illustrated in Fig. 1. However, other microphone positions as well as directional microphone arrangements may be applied within the scope of the invention.