Space-saving antenna for a hearing instrument

Abstract

Antenna (18), in particular magnetic-inductive antenna (18), for a hearing instrument (2), - with a first antenna surface (30) and a second antenna surface (32), each formed from magnetic, flexible foil (22), - with a base (34) formed from a magnetic material or comprising a magnetic layer (22) which connects the two antenna surfaces (30, 32) to one another, wherein the two antenna surfaces (30, 32) are angled from the base (34) in the same direction at opposite end edges of the base (34) so ​​that the two antenna surfaces (30, 32) and the base (34) encompass an interior space from three sides, - with an antenna winding (46), characterized by - a guide body (64) which bears with a guide surface (68) against a surface of the base (34) facing the interior.

Description

[0001] The invention relates to an antenna according to the preamble of claim 1, in particular a magnetic inductive antenna (MI antenna for short, i.e. an antenna for magnetic-inductive near-field transmission), for a hearing instrument and to a hearing instrument with such an antenna.

[0002] A hearing instrument is generally defined as an electronic device that emits a sound signal into the ear of a person wearing the hearing instrument (also referred to as the "user" or "wearer"), thereby assisting that person's hearing. In a narrower sense, this particularly includes hearing aids designed to provide hearing-impaired wearers. Such hearing aids pick up ambient sound and transmit it to the user in a processed, particularly frequency-dependently amplified form as airborne and / or structure-borne sound, thereby compensating the user's hearing loss entirely or at least partially. Other hearing instruments process recorded ambient sound - similar to conventional hearing aids - but are designed to provide sound to users with normal hearing in order to protect their hearing in special situations (e.g. special sound-dampening hearing instruments for musicians) or to provide support in other ways.Hearing instruments are also understood to include devices that convert a wired or wirelessly received audio signal into airborne or structure-borne sound and transmit it to the user in this form, e.g. headphones, earpieces, etc.

[0003] There are various designs of hearing instruments. So-called "behind-the-ear" (BTE) devices are worn between the skull and the auricle, with the amplified sound signal being introduced into the person's ear canal via a sound tube or output via a sound transducer (also called a "receiver") located in the ear canal. Another type of hearing instrument is an "in-the-ear" (ITE) device, in which the entire hearing aid itself is inserted into the ear, specifically into the ear canal. There are also hearing instruments that transmit sound information in the form of structure-borne sound or that directly stimulate the auditory nerve.

[0004] Magnetic inductive near-field transmission is used in hearing instruments as an alternative to traditional radio transmission technologies (e.g., Bluetooth) for the wireless transmission of data, especially audio signals, to external devices. In particular, magnetic inductive near-field transmission is often used for communication between two hearing instruments in a binaural hearing system. Furthermore, magnetic inductive methods are also used for energy transmission, i.e., for the wireless charging of rechargeable batteries in hearing instruments.

[0005] To date, the MI antennas required for this purpose (i.e., for magnetic-inductive data and / or power transmission) have typically been manufactured by wrapping a ferrite core with an antenna winding (also called a coil). The antenna performance can be increased by using larger ferrite cores, special windings, and special ferrite materials. However, due to the limited space, the sensitive (and thus susceptible to interference) electronics in hearing instruments, and the desire for the lowest possible weight, there are strict limits to the performance improvement of conventional MI antennas for use in hearing instruments.

[0006] WO 2017 / 153274 A1 describes a concept for an alternative design of an MI antenna, in which the cross-section of a coil core (base) wound with an antenna winding is expanded by flat magnetic foils. In this foil antenna, the antenna surfaces formed by the foils (referred to therein as "shields") are aligned approximately orthogonally to the axis of this base. The antenna surfaces are optionally provided with a paramagnetic or diamagnetic layer on the mutually facing inner sides, which magnetically shields the interior space formed between the antenna surfaces. Electrical or electronic components of the hearing aid (e.g., the battery) can therefore be accommodated in the interior space between the antenna surfaces in a space-saving manner.

[0007] Further developments of this antenna design are disclosed in DE 10 2018 209 189 A1 and DE 20 2018 104 183 U1. According to DE 10 2018 209 189 A1, the antenna surfaces angled away from the base are partially formed into lateral coil core sections that flank the base on both sides and each carry another coil. The antenna winding thus comprises three coils angled relative to each other with respect to their axes. According to DE 20 2018 104 183 U1, the magnetic coil forming the antenna winding is integrated into a flexible circuit board. This circuit board is provided with two conductor layers that sandwich the magnetic foil between them. The two conductor layers are each divided into a plurality of conductor tracks, whereby opposite conductor tracks of the two conductor layers are electrically connected to each other via vias to form the antenna winding.

[0008] EP 3 614 494 A1 discloses another variant of a foil antenna. Here, the antenna surfaces are formed from separate magnetic foil blanks. The base, wound with the antenna winding, has an opening on each of its two end faces, into which one of the foil blanks is inserted.

[0009] An antenna according to the preamble of claim 1 is known from DE 10 2021 201 095 A1.

[0010] The invention is based on the object of further improving an antenna for a hearing instrument, particularly with regard to manufacturing aspects. In particular, the antenna should be particularly easy and inexpensive to manufacture.

[0011] This object is achieved according to the invention by an antenna having the features of claim 1. Advantageous embodiments of the invention are set out in the subclaims and the following description.

[0012] The antenna according to the invention is intended and suitable for use in a hearing instrument, in particular a hearing aid. The antenna is preferably a magnetic inductive antenna (MI antenna) configured for data and / or energy transmission in the magnetic near field, in particular at frequencies up to approximately 300 MHz (megahertz). The antenna has a first antenna surface and a second antenna surface, each formed from a magnetic, flexible foil, in particular a ferrite foil.

[0013] The antenna further comprises a base made of a magnetic material or at least comprising a magnetic layer. The base is arranged between the two antenna surfaces and connects the two antenna surfaces mechanically and magnetically to one another. The two antenna surfaces are angled away from the base in the same direction, so that the base, together with the two antenna surfaces, forms approximately the shape of a letter "U". The (fold) lines along which the two antenna surfaces are angled away from the base are also referred to below as the "front edges" of the base. The two antenna surfaces and the base enclose a spatial volume (also referred to as the "interior") on three sides. The sides of the two antenna surfaces and the base facing this interior are each referred to as the "inner sides".The sides of the two antenna surfaces and the base opposite these inner sides are referred to as "outer sides." The terms "inside" and "outside" are used accordingly. The two antenna surfaces are in particular (but not necessarily) angled at right angles to the base, so that the antenna surfaces are parallel to each other on either side of the interior. The two antenna surfaces are preferably symmetrical to each other.

[0014] The antenna finally includes an antenna winding.

[0015] Within the scope of the invention, the antenna winding can in principle be wound around the base. Preferably, however, the antenna winding comprises at least a first single-layer spiral coil. This first spiral coil is arranged on the outside of the first antenna surface, so that a (coil) axis of the first spiral coil is oriented perpendicularly with respect to the first antenna surface. The spiral coil is, in particular, attached to the first antenna surface, in particular, glued (directly or indirectly) to the first antenna surface.

[0016] A single-layer spiral coil is understood here to mean a magnetic coil in the form of a flat (e.g., round, polygonal, or irregularly shaped) spiral, in which the coil wire or conductor winds in more than one turn with varying diameter within the same area. In certain embodiments of the invention, the antenna winding consists exclusively of the first spiral coil. However, in order to achieve greater antenna efficiency for a given antenna size, the antenna winding comprises at least one additional spiral coil in expedient embodiments of the invention.

[0017] Thus, in one variant of the invention, in addition to the first spiral coil, a second single-layer spiral coil is provided, which is arranged on the outside of the second antenna surface, in particular, is attached so that an axis of this second spiral coil is oriented perpendicularly with respect to the second antenna surface. In expedient embodiments, the second spiral coil is constructed identically to the first spiral coil and / or is arranged centered relative to the first spiral coil (i.e., coaxial with respect to the two coil axes).

[0018] Alternatively or in addition to the second spiral coil, in a further variant of the invention, the antenna comprises at least a third single-layer spiral coil, which is arranged, in particular attached, on the outside and—with respect to the spiral plane—parallel to the first spiral coil on the first antenna surface. In expedient embodiments, the third spiral coil is also constructed identically to the first spiral coil and / or is arranged centered relative to the first spiral coil (i.e., again coaxial with respect to the two coil axes).

[0019] Within the scope of the invention, the antenna may contain additional second or third spiral coils flanking the second or first antenna surface, respectively. The terms "second" spiral coil and "third" spiral coil thus serve only to clearly identify the respective spiral coil with regard to its arrangement relative to the first spiral coil, but not to count the spiral coils. Accordingly, in certain embodiments of the invention, the antenna may also have only the first spiral coil and one or more third spiral coils, but no second spiral coil.

[0020] The possibly present several single-layer spiral coils can be permanently connected to one another within the scope of the invention (in particular electrically connected in series) and thus together form a multi-layer antenna winding. In a particularly advantageous embodiment of the invention, however, both spiral coils or at least two of possibly several spiral coils can be controlled independently of one another, i.e. coupled to a corresponding circuit for transmitting or receiving a signal or for supplying or withdrawing energy. The independent control of at least two spiral coils enables, on the one hand, a temporary increase in the transmission power of the antenna by switching off one spiral coil and the associated increase in the current strength of the winding current. The independent control of at least two spiral coils also enables a temporary increase in the antenna efficiency by switching on a spiral coil.

[0021] In particularly advantageous embodiments of the invention, the or each spiral coil is manufactured using RFID technology (i.e., similar to the antenna coil of an RFID transponder). The spiral coil is produced, in particular, by printing, galvanic deposition, vapor deposition, sputtering, etching of conductor tracks, or by embedding a coil wire on a carrier foil. The use of RFID technology to manufacture the or each spiral coil has the advantage that the or each spiral coil can be manufactured particularly easily and cost-effectively.

[0022] In an equally practical alternative, the or each spiral coil is formed by a conductor track on a flexible printed circuit board. This has the particular advantage that the spiral coil can be manufactured relatively easily, integrated with the associated control electronics and, optionally, with the signal processing system that is usually already present in the hearing instrument.

[0023] To further simplify manufacturing and achieve particularly high antenna efficiency, the two antenna surfaces and the base are preferably formed by a single piece of magnetic foil. Alternatively, the two antenna surfaces and the base are formed by two pieces of magnetic foil, each extending into the base area.

[0024] Analogous to the foil antennas known from the prior art, the two antenna surfaces are preferably each widened relative to the base. In particular, the two antenna surfaces each have a circular widening, as is known per se from the antennas disclosed in EP 3 614 494 A1.

[0025] In order to favorably shape the antenna's magnetic field and thus significantly increase the antenna's efficiency while taking into account limited installation space and / or the antenna's maximum weight, the antenna preferably has a first magnetic reflection layer made of an electrically conductive material with low magnetic permeability. This first reflection layer consists in particular of copper or aluminum, for example in the form of a foil or coating. The first reflection layer is arranged, in particular attached, on the outside of the first antenna surface and the second antenna surface, such that the first reflection layer is arranged between the antenna surfaces and the or each spiral coil. The or each spiral coil and the respectively associated antenna surface thus accommodate the first reflection foil between them in a sandwich-like manner.In the region of each of the two antenna surfaces, the first reflective layer has a recess (i.e., a hole) through which the magnetic flux is introduced into the antenna surfaces in a concentrated manner and is discharged from the antenna surfaces. The or each spiral coil is arranged in the region of one of the two recesses, in particular centered with respect to the associated recess. In embodiments of the antenna in which one or more spiral coils are associated only with the first antenna surface, the first reflective layer on the second antenna surface is optionally omitted. In this case, the first reflective layer covers only the first antenna surface and preferably the base.

[0026] In a preferred embodiment of the invention, the first reflective layer is dimensioned such that it projects laterally beyond the antenna surfaces (i.e., transversely to the axis of the or each spiral coil). This achieves particularly effective field shaping. Preferably, the first reflective layer covers not only the two antenna surfaces, but also the base, in order to prevent, as far as possible, any undesired escape of stray magnetic fields from the magnetic material of the base. In particular, the first reflective layer forms a continuous surface covering the two antenna surfaces and the base.

[0027] Preferably, the first reflective layer has a slot in the area of ​​each antenna surface on the side facing away from the base, extending from the respective recess to the outer edge of the first reflective layer. Due to the slot, the first reflective layer is therefore not closed in a ring around the recesses, thereby counteracting the occurrence of disruptive circulating currents in the first reflective layer.

[0028] In addition or alternatively to the first reflective layer, the antenna preferably has a second magnetic reflective layer made of an electrically conductive material with low magnetic permeability, in particular copper or aluminum. This second reflective layer is arranged, in particular attached, to the inside of the first antenna surface and the second antenna surface. The second magnetic reflective layer also preferably extends over the base and expediently forms a continuous surface covering the two antenna surfaces and the base.

[0029] The antenna has the particular advantage of being very lightweight and requiring very little installation space, as it is formed exclusively from very thin foils or layers (namely the magnetic foil, in particular ferrite foil, the optionally present first and / or second reflection layer, and the at least one winding layer). Due to the U-shaped structure formed by the antenna surfaces and the base connecting them, the antenna encloses a comparatively large volume while requiring little installation space. Due to this large volume, the antenna, on the one hand, has high performance; in particular, the antenna generates a magnetic field profile in the excited state that approximately corresponds to that of a rod antenna of the same volume.Unlike such a rod antenna, however, the enclosed volume is largely empty and can therefore be used to house at least one other component of the hearing instrument, particularly a battery. Placing the battery or another component with a metal housing in the interior space enclosed by the antenna has the additional effect that the metal housing guides the magnetic flux within the antenna's magnetic foil, thus further enhancing the antenna's performance.

[0030] The antenna has the further advantage that, even compared to conventional foil antennas, it is very simple and cost-effective to manufacture due to the flat design of the coil(s) using RFID technology or on a printed circuit board. The design of the coil(s) on a printed circuit board has the additional advantage that the coil(s) can be integrated (and preferably are integrated) with the signal processing and / or control electronics of the hearing instrument on a common circuit board, thereby reducing the assembly effort for the hearing instrument. In particular, this eliminates the effort required for soldering or otherwise contacting the antenna winding with the associated transmitting and / or receiving circuit or the charging electronics of the hearing instrument.

[0031] An additional advantage of the antenna is that it is highly flexible and thus adaptable to the structural constraints of the hearing instrument. This allows the antenna to be adapted, in particular, to various body shapes. The windings of the coil(s) do not necessarily have to be round. Rather, within the scope of the invention, they can also take on other shapes, in particular angular, oval, organic shapes, or a combination of these shapes (e.g., a contour adapted to the shape of the hearing instrument). To achieve the highest possible performance, the shape of the coil(s) is preferably designed so that the antenna winding fills the maximum available area.Furthermore, the antenna can be easily adapted to the desired performance and / or inductance for the respective application by selecting the number of single-layer spiral coils. In particular, adding one or more spiral coils allows for high antenna performance and / or inductance even with a very small usable area.

[0032] In one practical method for mounting the antenna, one of the two antenna surfaces is first fixed with one end face to a surface of a component to be accommodated in the interior of the antenna (in particular to an end face of the battery), in particular by adhesive bonding. The base and the other antenna surface are then folded around the component. Finally, the other antenna surface is fixed to an opposite surface of the component (in particular to the other end face of the battery). This mounting method, while simple in itself, has proven difficult to implement, as precise centering of the antenna surfaces relative to one another and to the component can only be achieved with comparatively great effort. This is due, on the one hand, to manufacturing tolerances of the magnetic foil and the other components.On the other hand, experience has shown that the magnetic layer (especially the ferrite layer) of the magnetic foil tends to break irregularly and irreproducibly when the foil blank is folded around the component. The manufacturing variances of the antenna are thus significantly increased by the assembly process described above, especially since the degrees of freedom for positioning the second antenna surface on the component are limited by the preceding process steps.

[0033] In order to enable a simple, but at the same time precise and reproducible assembly of the antenna, a further development of the invention proposes several measures described in more detail below, which - unless otherwise described - can be used independently of one another or in any combination with one another.

[0034] According to a first of the aforementioned measures, the antenna according to the invention additionally comprises a guide body, which rests with a guide surface against a surface of the base facing the interior. The guide body, which is preferably formed by an injection-molded plastic part, is therefore located in the assembled state of the antenna, in particular between the base and the component accommodated in the interior of the antenna (in particular the battery). The guide body supports the centering of the antenna with respect to the component (and thus also the centering of the antenna surfaces with respect to one another), as it facilitates an assembly process starting from the base (and thus symmetrical). Preferably, the base is first connected to the guide body. The guide body is then placed on the component to be accommodated in the interior of the antenna. The two antenna surfaces are subsequently folded around the component on both sides and fixed to it.The precision of this assembly process is increased in a practical embodiment by providing an inner side of the guide body with a contour complementary to the component, so that the guide body can be placed on the component with a precise fit (in particular self-centering).

[0035] In order to increase the reproducibility of the folding process in which the two antenna surfaces are angled away from the base, and in particular to avoid irregular, irreproducible bridging of the magnetizable layer of the magnetic foil or at least to keep it small, the guide body is preferably provided in the region of the front edges of the base on its guide surface with a (cylindrical) convex guide radius over which the magnetic foil is guided when the antenna surfaces are angled away from the base.

[0036] Additionally or alternatively, in a suitable embodiment, the guide body has at least one (e.g., pin-shaped) centering projection protruding from the guide surface, which engages in a corresponding recess or hole in the base for positioning (centering) the base. In a further suitable embodiment, the guide body is provided with parapet webs or projections on both sides of the guide surface, between which the base lies. This design ensures that the base (and thus indirectly also the antenna surfaces) are held in the guide surface with a positive fit.

[0037] Optionally, the guide body is provided with additional functional structures, e.g. structures for fixing a printed circuit board and / or structures for guiding winding wires.

[0038] According to a second measure, the or each foil blank is preferably provided with a predetermined bending point in the area between one of the two antenna surfaces and the base, in that the magnetic foil is locally weakened at this point by at least one indentation. In various variants, either a large number of point-shaped indentations or one or more linear indentations are introduced into the magnetic foil. The indentations are produced in particular by material removal using laser radiation (laser cutting). The or each indentation can be introduced into the magnetic foil with different depths, but preferably in such a way that it does not completely penetrate the foil. The or each indentation is furthermore preferably introduced on the inner side of the magnetic foil facing the interior.When the magnetic foil is bent, the recesses are located on the concave side of the bends, and are thus completely or at least partially pushed back together by the foil material when the magnetic foil is bent. The predetermined bends prevent irregular fractures in the magnetizable layer, which in turn reduces the manufacturing tolerance during antenna assembly.

[0039] A third measure for achieving simple, yet precise and reproducible antenna assembly is used in antenna designs in which the antenna surfaces and the base are composed of two foil blanks of the magnetic foil. Each of the two foil blanks has one of the two antenna surfaces and at least one tab protruding (in particular radially) from the edge of the respective antenna surface. To form the base, the tabs of one of the two foil blanks, or one of several tabs, are placed overlapping on a (respectively) corresponding tab of the other foil blank.

[0040] Forming the antenna surfaces and the base from two foil sections allows for independent (and thus particularly precise) fixation of both antenna surfaces to the component to be housed inside the antenna. Furthermore, manufacturing tolerances (as well as different component thicknesses) can be compensated for by overlapping the tabs to varying degrees without significantly affecting the magnetic properties of the antenna. Furthermore, the two foil sections are preferably manufactured identically, which simplifies the manufacturing process.

[0041] If the two foil blanks each have multiple tabs, the antenna base formed by these tabs is divided into several independent strands. The order in which the tabs of the two foil sections are placed on top of each other is preferably alternated. The multi-strand design of the base enables the realization of a base with a comparatively large cross-section (and thus a good magnetic coupling between the two antenna surfaces) without the base protruding significantly radially beyond the component housed in the interior.In other words, dividing the base into several strands—each formed from corresponding tabs of two foil sections—allows the base to be easily wrapped around the perimeter of the component housed in the interior, so that, despite a particularly compact antenna shape, good magnetic coupling between the two antenna surfaces is still achieved. Furthermore, several narrow tabs can be angled away from the antenna surface more easily and with a lower risk of irregular fractures of the magnetizable layer than a wider tab with the same overall cross-section.

[0042] Preferably, the magnetic foil of the two foil blanks is formed from a magnetizable layer, in particular a ferrite layer or ferrite powder layer, which is sandwiched on both sides by a plastic layer (in particular made of polyethylene terephthalate, or PET for short). In this case, in an expedient embodiment of the invention, one of the plastic layers is removed in the or each overlapping area of ​​the corresponding tabs, so that the corresponding tabs each lie directly on top of one another with the magnetizable layer. This further improves the magnetic coupling between the antenna surfaces.

[0043] A particular embodiment of the invention is a hearing instrument equipped with the above-described antenna according to the invention, in particular in one of the above-described embodiments. The hearing instrument has, in particular in a conventional manner - inside or outside a housing - an output transducer, e.g. a receiver for outputting a sound signal into the ear of a user. The hearing instrument preferably furthermore has a (programmable, non-programmable or partially programmable) signal processor for processing, in particular amplifying, the sound signal to be output to the user. Furthermore, the hearing instrument preferably has an input transducer, in particular at least one microphone, for detecting ambient sound, wherein this detected ambient sound is output via the output transducer after processing, in particular amplification.

[0044] In expedient embodiments, the hearing instrument has a functional component, e.g. a (rechargeable or non-rechargeable) battery or a receiver, wherein this functional component is provided with a housing made of an electrically conductive material with low magnetic permeability, in particular of copper, aluminum or sheet steel. The antenna is placed on the functional component in such a way that the housing tightly flanks the antenna surfaces (and preferably also the base) on the inside. The housing of the functional component thereby fulfills the function of the second reflection layer described above, which is therefore obsolete in this embodiment and is therefore preferably not present. Preferably, the housing lies directly against the respective inner side of the antenna surfaces and optionally also against the inner side of the base.

[0045] Within the scope of the invention, the antenna according to the invention can, in principle, be advantageously used in any hearing instrument of the type described above, in particular also in headphones, earpieces, etc. Preferably, however, the hearing instrument according to the invention is a hearing aid, which can optionally be provided, for example, as a BTE or ITE device.

[0046] The following examples are explained in more detail using a drawing. They show: Fig. 1 shows a schematic representation of a previously known hearing instrument, here in the form of a behind-the-ear hearing aid, with a battery and an antenna mounted thereon, Fig. 2 shows the antenna of the hearing aid in perspective Fig. 1, wherein the antenna comprises a ferrite foil, a first reflection foil applied externally to the ferrite foil and an antenna winding applied externally to the first reflection foil, wherein the antenna winding is formed from a single-layer spiral coil, Fig. 3 in representation according to Fig. 2 the antenna in the state attached to the battery of the hearing instrument, Fig. 4 in representation according to Fig. 3 the battery and the ferrite foil of the antenna, Fig. 5 in representation according to Fig. 3 the battery as well as the ferrite foil and the first reflection foil of the antenna, Fig. 6 the ferrite foil of the antenna in unfolded state, Fig. 7 the first reflective foil of the antenna in an alternative embodiment, in which two single-layer spiral foils of the antenna winding are applied to the first reflective foil, wherein the two spiral foils are applied to opposite longitudinal ends of the first reflective foil, Fig. 8 shows a schematic cross-section of the battery and the antenna mounted on it according to Fig. 2, Fig. 9 in representation according to Fig. 8 an alternative embodiment of the antenna in which the antenna winding comprises two single-layer spiral coils mounted on top of each other, Fig. 10 in representation according to Fig. 8 shows a further embodiment of the antenna with a second reflection foil applied to the inside of the ferrite foil, Fig. 11 and Fig. 12 shows, in different perspective views, an embodiment of the antenna according to the invention with a guide body for guiding and centering the ferrite foil with respect to the battery, Fig. 13 in a cross-section the antenna mounted on the battery according to Fig. 11, Fig. 14 to 17 each show, in plan view, four different designs of the ferrite foil, which here has a predetermined bending point in the areas between one of the two antenna surfaces and the base, in which the ferrite foil is locally weakened by one or more depressions, Fig. 18 in a schematic cross-section the ferrite foil with three different depths of depressions of one of the predetermined bending points, and Fig. 19 and Fig. 20 shows various perspective views of an embodiment of the antenna, which is composed of two foil cuts of the ferrite foil, wherein the antenna is placed on the battery, Fig. 21 in isolated perspective view a foil cut of the antenna according to Fig. 19, and Fig. 22 and Fig. 23 shows a perspective view and a top view of a variant of the antenna formed from two foil cut-outs.

[0047] Corresponding parts are always provided with the same reference symbols in all figures.

[0048] Fig. Figure 1 shows a hearing instrument, which in this case is a hearing aid 2 for supporting the hearing of a hearing-impaired user. In the example shown here, the hearing aid 2 is a BTE hearing aid that can be worn behind a user's ear, as is already known from DE 10 2021 201 095 A1.

[0049] Within a housing 4, the hearing aid 2 comprises two microphones 6 as input transducers and a receiver 8 as output transducer. The hearing aid 2 further comprises a battery 10 and signal processing in the form of a signal processor 12. Preferably, the signal processor 12 comprises both a programmable subunit (e.g., a microprocessor) and a non-programmable subunit (e.g., an ASIC).

[0050] The signal processor 12 is supplied with an electrical supply voltage U from the battery 10.

[0051] During normal operation of the hearing aid 2, the microphones 6 each record airborne sound from the environment of the hearing aid 2. The microphones 6 each convert the sound into an (input) audio signal I containing information about the recorded sound. The input audio signals I are fed within the hearing aid 2 to the signal processor 12, which modifies these input audio signals I to support the user's hearing.

[0052] The signal processor 12 outputs an output audio signal O, which contains information about the processed and thus modified sound, to the listener 8.

[0053] The receiver 8 converts the output sound signal O into a modified airborne sound. This modified airborne sound is transmitted into the user's ear canal via a sound channel 14, which connects the receiver 8 to a tip 16 of the housing 4, and via a flexible sound tube (not explicitly shown) which connects the tip 16 to an earpiece inserted into the user's ear canal.

[0054] In order to be able to exchange data with peripheral devices such as a second hearing aid for supplying the user's second ear, the hearing aid 2 further comprises an antenna 18. The antenna 18 is an MI antenna that uses magnetic inductive near-field transmission for data exchange. To control the antenna 18, the hearing aid 2 comprises a transmit / receive circuit 20 connected to it, which is connected on the one hand to the antenna 18 and on the other hand to the signal processor 12 of the hearing aid 2. Additionally or alternatively, the antenna 18 serves to wirelessly receive energy in order to charge the battery 10. In this case, the antenna 18 is (if necessary also) connected to an electronic charging control of the hearing aid 2, which controls the charging process of the battery 10.

[0055] According to Fig. 2, the antenna 18 comprises, instead of a solid magnetic core, a magnetic, flexible foil, here in the form of a ferrite foil 22, which has a thickness of approximately 30 to 400 µm (micrometers), preferably 50 to 300 µm and in particular 100 µm. As can be seen in particular from the Fig. 2, Fig. 4 and Fig. 6, the ferrite foil 22 is formed by a (preferably one-piece) dumbbell-shaped blank. In the exemplary embodiment shown here, the ferrite foil 22 thus has a circular widened portion 26 at each of its opposite longitudinal ends 24, wherein the two widened portions 26 are connected by a narrower connecting portion 28. To form the antenna 18, the ferrite foil 22 is folded into a U-shaped contour, the legs of which are each formed by one of the two widened portions 26 and an adjacent piece of the connecting portion 28. The legs of the U-shaped contour, i.e., the two widened portions 26 and the adjacent pieces of the connecting portion 28, thus form two parallel and spaced-apart antenna surfaces 30 and 32 opposite one another. The part of the connecting portion 28 connecting these two antenna surfaces 30 and 32 is referred to as the base 34.

[0056] As can be seen from the Fig. 2 and Fig. 5, a copper reflective foil 36 is applied to the outside of the ferrite foil 22 as the first reflective layer, which reflective foil is preferably glued to the ferrite foil 22. The reflective foil 36 has a shape adapted to the ferrite foil 22, in the case of the present example also a dumbbell shape. However, compared to the ferrite foil 22, it is provided with larger widened portions 38 at its longitudinal ends 40, so that the reflective foil 36 projects laterally beyond the edge of the ferrite foil 22 in the region of the antenna surfaces 30 and 32. Furthermore, the reflective foil 36 is provided with a central circular recess 42 in the region of its widened portions 38, so that the widened portions 38 each have the shape of a circular ring.On their sides facing away from the base 34 (i.e. at the longitudinal ends 40 of the reflective foil 36), the circular widenings 38 are each interrupted by a thin slit 44 which extends from the respective recess 42 to the outer edge of the reflective foil 36.

[0057] The antenna 18 finally comprises an antenna winding 46. In the Fig. In the embodiment illustrated in Figures 2 to 6 and 8, this antenna winding 46 is formed by a single-layer spiral coil 48, which in turn is applied to the outside of the reflective foil 36. The spiral coil 48 is arranged centered with respect to the widened portion 26 of the ferrite foil 22 and the widened portion 38 of the reflective foil (and thus also centered with respect to the recess 42 made in the latter). Unlike the conventional foil antennas described above, the antenna winding 46 is therefore not wound around the ferrite foil 22 or any other magnetic core. Rather, the spiral coil 48 is arranged with respect to the ferrite foil 22 such that the coil axis 49 (Figures 3 and 7) of the spiral coil 48 is perpendicular to the surface area of ​​the ferrite foil 22 and thus perpendicular to the antenna surface 30.

[0058] In a preferred embodiment, the spiral coil 48 is formed in the manner of the antenna coil of an RFID transponder. For this purpose, it is formed in particular by an electrical conductor track printed on a carrier film 50 or embedded in the carrier film 50 (see in particular Fig. 8), wherein this carrier foil 50 is preferably glued to the reflective foil 36. The carrier foil 50 provided with the spiral coil 48 is also collectively referred to as the winding foil 52.

[0059] As can be seen in particular from the Fig. 3 to 5 and 8, the antenna 18 in the assembled state is placed on the (cylindrical) battery 10 in such a way that the antenna surfaces 30 and 32 closely flank the two end faces of the battery 10 or even lie against the end faces of the battery 10.

[0060] Like the Fig. 3 and Fig. 5, the reflective foil 36 is dimensioned such that the widened portions 38 approximately correspond in shape and size to the end faces of the battery 10. The spiral coil 48, in turn, is dimensioned such that it largely utilizes the area spanned by the corresponding widened portion 38 of the reflective foil 36.

[0061] During operation of the antenna 18, the magnetic field generated by the antenna winding 46 is shaped by the perforated reflective foil 36 such that the magnetic field of the antenna 18 approximately corresponds to the magnetic field of a rod antenna with a length equal to the distance between the antenna surfaces 30 and 32. The reflective foil 36 and a metal housing 54 of the battery 10 force the magnetic field in the interior region between the antenna surfaces 30 and 32 to run largely inside the ferrite foil 22. The metal housing 54 of the battery 10 thus acts as an internal magnetic reflective layer, which on the one hand magnetically shields the interior space enclosed by the antenna 18 and on the other hand increases the performance of the antenna 18.

[0062] In order to further increase the performance of the antenna 18 within a given installation space (and thus limited size), one or more additional spiral coils are added to the antenna winding 46 in further embodiments of the antenna 18.

[0063] Based on Fig. 7, which illustrates the reflective foil 36 with the antenna winding 46 applied thereon in the unfolded state, shows an embodiment of the antenna 18 in which the antenna winding 46 comprises, in addition to the spiral coil 48, a further single-layer spiral coil 56. This further spiral coil 56 is attached to the other antenna surface 32. In this embodiment, the antenna 18 is designed symmetrically with respect to the shape of the ferrite layer 22 and the reflective layer 36, as well as with respect to the structure (in particular with respect to the arrangement of the two spiral coils 48 and 56), so that the two spiral coils 48 and 56 are arranged coaxially with respect to their coil axes 49 in the (folded) assembled state of the antenna 18. The coil axis 49 of the spiral coil 56 is also aligned perpendicular to the surface area of ​​the ferrite foil 22 (and thus perpendicular to the antenna surface 32).

[0064] In the execution according to Fig. 7, the two spiral coils 48 and 56 are connected to a common electrical supply line 58 and are electrically connected in series. In an alternative embodiment, however, the two coils 48 and 56 are connected separately to the transmit / receive circuit 20 and can be individually switched on and off as needed during operation of the antenna 18, or controlled independently of each other in some other way. In one embodiment of the antenna 18, only the signal coil 48 is connected to the transmit / receive circuit 20, while the signal coil 56, as a charging coil, is connected to the charging control of the hearing aid 2.

[0065] In a further embodiment of the antenna 18, the antenna winding 46 comprises, in addition to the spiral coil 48, also a further single-layer spiral coil 60, wherein this further spiral coil 60, however, according to Fig. 9 is attached to the antenna surface 30 together with the spiral coil 48. The spiral coil 60 is preferably attached directly to the spiral coil 48, in particular glued to the latter. The two spiral coils 48 and 60 are preferably arranged relative to one another such that they are coaxial with one another with respect to their coil axes 49.

[0066] Also in the execution according to Fig. 9, the two spiral coils 48 and 60 are preferably electrically connected in series and thus controlled jointly. The two single-layer spiral coils 48 and 60 thus together form a multi-layer coil. Alternatively, the two coils 48 and 60 can again be controlled separately from one another within the scope of the invention.

[0067] In order to further increase the performance of the antenna 18, additional spiral coils are added to the two spiral coils 48 and 56 or 48 and 60 if required, which can be arranged optionally on the antenna surface 30 and / or on the antenna surface 32.

[0068] The spiral coils 48 and 56, or 48 and 60, as well as any additional spiral coils, are preferably manufactured identically and are thus each provided in the form of a cost-effectively manufactured and easily handled winding foil 52. However, the antenna winding 46 can also comprise coils of different designs (particularly with regard to the number of turns and the diameter).

[0069] In a further embodiment, the antenna 18 comprises Fig. 10 as a second reflection layer, a further reflection foil 62, which is applied to the inside of the ferrite foil 22. This further reflection foil 62 preferably has a shape corresponding to the reflection foil 36 (but without the recesses 42 and the slots 44) and is arranged in register with the reflection foil 36, so that the reflection foils 36 and 62 envelop the ferrite foil 22 in a sandwich-like manner. The reflection foil 62 is preferably formed analogously to the reflection foil 36 by a metal foil made of copper or aluminum and is preferably glued to the ferrite foil 22 and the reflection foil 36. The inner reflection foil 62 improves the magnetic shielding of the interior enclosed by the antenna 18 and the conduction of the magnetic flux in the interior of the ferrite foil 22. It is provided in particular when, in the installation situation of the antenna 18 in this interior, deviating from Fig. 1 to 5 magnetically susceptible components are arranged which are themselves not sufficiently magnetically shielded.

[0070] The reflective foil 62 can also be provided to prevent heating of metallic bodies in the interior of the antenna 18 (e.g. the metal housing 54 of the battery 10) due to eddy currents.

[0071] In the Fig. 11 to 13 show a modification of the antenna 18 according to the invention. In this exemplary embodiment, the antenna 18 additionally comprises a guide body 64 formed by a plastic injection-molded part. The guide body 64 is arranged between the base 34 and the battery 10 when the antenna 18 is in the assembled state. On its inner side 66 facing the battery 10, the guide body 64 is provided with a shape that is at least approximately complementary to the circumferential contour of the battery 10. With this inner side 66, the guide body 64 is placed precisely on the circumference of the battery 10. Opposite the inner side 66, the guide body 64 has a guide surface 68 with which the guide body 64 rests against the base 34. The guide surface 68 is flanked on both sides by projections 70 and 72, which hold the base 34 between them in a form-fitting manner and thus center it.The projections 72 are also provided with contours that guide electrical leads 74 of the antenna winding 46 to a printed circuit board 76. For additional fixation and centering of the base 34 (and thus of the two antenna surfaces 30 and 32), the guide body 64 is provided with two guide pins 78 projecting from the guide surface 68 and extending through corresponding holes 80 in the base.

[0072] To mount the antenna 18, the base 34 is first connected (e.g., by gluing) to the guide body 64. The guide body 64 is then placed on the circumference of the battery 10. Subsequently, the two antenna surfaces 30 and 32 are folded around the battery 10 on both sides and secured to it (e.g., again by gluing).

[0073] In order to increase the reproducibility of the folding process in which the two antenna surfaces 30 and 32 are angled from the base 34, and in particular to avoid irregular, irreproducible fractures of the ferrite layer 86 ( Fig. 18) of the ferrite foil 22 or at least to keep it small, the guide body 64 is provided in those areas of the guide surface 68 where the base 34 merges into the angled antenna surfaces 30 and 32 (ie in the area of ​​the front edges of the base 34) with a (cylindrically) convexly curved guide radius 81, over which the ferrite foil 22 is guided.

[0074] In each of these bending or curvature areas, in which the base 34 merges into the angled antenna surfaces 30 and 32, the ferrite foil 22 is arranged according to the Fig. 14 to 17, each provided with a predetermined bending point 82. The predetermined bending points 82 are produced by removing material by means of laser radiation (laser cutting) to create point-shaped or linear depressions 84 in the ferrite foil 22, which locally weaken the ferrite foil 22, but preferably do not completely penetrate it. Fig. 14 to 17 show different embodiments of these recesses 84: - According to Fig. 14, a serrated, linear recess 84 is provided at each predetermined bending point 82. - According to Fig. 15, a uniform pattern of point-shaped depressions 84 is provided at each predetermined bending point 82. - According to Fig. 16, at each predetermined bending point 82, a plurality of depressions 84 in the form of straight lines are provided, which extend transversely across the ferrite foil 22. - According to Fig. 17, several irregular, linear depressions 84 are provided at each predetermined bending point 82, each of which has approximately the shape of a letter “U” with two legs of unequal length.

[0075] In Fig. 18, the cross-sectional shape of the depressions 84 is illustrated by means of a roughly schematic cross-section through the ferrite foil 22. From the illustration, it can be seen that the ferrite foil 22 has a central ferrite layer 86, which is sandwiched on both sides by a plastic layer 88 and 90 (e.g., made of polyethylene terephthalate, PET). Fig. 18 marked depressions 84 it is clear that the Fig. 14 to 17 shown recesses 84 can each be designed with different depths. In a first embodiment variant (in Fig. 18 left), the recess 84 essentially only penetrates the plastic layer 88, while the ferrite layer 86 is not touched or is merely scratched. In a second embodiment (in Fig. 18 in the middle), the recess 84 penetrates deeply, in particular by about 50% of its layer thickness, into the ferrite layer 22. In a third embodiment (in Fig. 18 right), the recess 84 penetrates not only the plastic layer 88 but also the ferrite layer 22 completely or at least almost, so that only the plastic layer 90 is not touched or is only scratched. The three designs of the recesses 84 described above span a continuous design area, within which the recesses 84 in the Fig. 14 to 17 can be varied. Furthermore, several recesses 84 of varying depths or (linear) recesses 84 with varying depths can be provided on one and the same ferrite foil 22.

[0076] In the Fig. In the ferrite foils 22 shown in Figures 14 to 18, the recesses 84 are formed on the inner side of the ferrite foil 22 facing the battery 10. Thus, in the angled state of the ferrite foil 22, the recesses 84 are located on the concave side of the bending points and are completely or at least partially pushed back together by the material of the ferrite foil 22 when the magnetic foil is bent. The predetermined bending points 82 prevent irregular fractures of the ferrite layer 86.

[0077] While in the above-described embodiments of the antenna 18 the antenna surfaces 30, 32 and the base 34 were always formed from a one-piece cut of the ferrite foil 22, in the embodiments described below with reference to the Fig. In the examples described in Figures 19 to 23, the antenna surfaces 30, 32 and the base 34 are composed of two foil blanks 92 and 94 of the ferrite foil 22. Each of the two foil blanks 92, 94 has one of the two antenna surfaces 30, 32 and at least one tab 96 protruding (in particular radially) from the edge of the respective antenna surface 30, 32. To form the base 34, the tab 96, or one of possibly several tabs 96, of one of the two foil blanks 92, 94 are placed in an overlapping manner on a (respectively) corresponding tab 96 of the other foil blank 94 or 92.

[0078] In one embodiment of the antenna 18 (not shown in detail), a single tab 96 protrudes from each of the antenna surfaces 30, 32. The superimposed tabs 96 of the two foil blanks 92, 94 form - similar to the embodiments according to Fig. 2 to 18 - a single-stranded variant of base 34.

[0079] Deviating from this, in an embodiment of the antenna 18 according to the Fig. 19 to 21, a tab 96 is cut off from each of the antenna surfaces 30, 32, which branches into two branches 98, 100 in the area of ​​the base 34. The alternately superimposed branches 98, 100 of the tabs 96 of the two foil blanks 92, 94 form a two-strand variant of the base 34.

[0080] In a further embodiment according to Fig. 22 and Fig. 23, two tabs 96 protrude radially from each of the antenna surfaces 30 and 32, with two of these tabs 96 being superimposed in alternating sequence to form a two-strand variant of the base 34. The tabs 96 are arranged distributed around the circumference of the antenna surfaces 30, 32 in such a way that the two strands of the base 34 are widely spaced from each other relative to their respective widths; specifically, the distance between the two strands of the base 34 here is, for example, approximately three times the width of the individual strand.

[0081] Furthermore, the two strands of base 34 in the example are Fig. 22 and Fig. 23 is arranged on the side of the battery 10 facing away from the circuit board 76. This can be advantageous in terms of installation space, depending on the arrangement of the components inside the hearing aid 2.

[0082] In the Fig. In the embodiments of the antenna 18 shown in Figures 19 to 23, the two foil blanks 92 and 94 are preferably manufactured as identical parts. This results in particularly efficient production.

[0083] Furthermore, the Fig. In the embodiments of the antenna 18 shown in Figures 19 to 23, one of the outer plastic layers of the ferrite foil 22 is removed from the overlapping surfaces of the tabs 96, so that the tabs 96 lie directly on top of the ferrite layer 86. This further improves the magnetic coupling between the antenna surfaces 30 and 32.

[0084] The invention is particularly clear from the exemplary embodiments described above, but is by no means limited to these exemplary embodiments. Rather, further embodiments of the invention can be derived from the claims and the above description. List of reference symbols 2 hearing aids 4 housings 6 microphones 8 listeners 10 Battery 12 Signal processor 14 sound channel 16 lace 18 Antenna 20 Transmit / receive circuit 22 Ferrite foil 24 Longitudinal end 26 Widening 28 connecting section 30 antenna area 32 antenna area 34 Base 36 reflective foil 38 Widening 40 Longitudinal end 42 recess 44 slot 46 Antenna winding 48 spiral coil 49 Coil axis 50 carrier foil 52 winding foil 54 metal housings 56 spiral coil 58 supply line 60 spiral coil 62 reflective foil 64 guide bodies 66 Inside 68 guide surface 70 lead 72 lead 74 supply line 76 circuit board 78 Guide pin 80 holes 81 guide radius 82 Predetermined bending point 84 Deepening 86 Ferrite layer 88 plastic layer 90 plastic layer 92 foil cutting 94 Foil cutting 96 tab 98 branch 100 branches I (Input) audio signal O Output audio signal U supply voltage

Claims

[1] Antenna (18), in particular a magnetic-inductive antenna (18), for a hearing instrument (2), - with a first antenna surface (30) and a second antenna surface (32), each formed from magnetic, flexible foil (22), - with a base (34) formed from a magnetic material or comprising a magnetic layer (22) which connects the two antenna surfaces (30, 32) to one another, wherein the two antenna surfaces (30, 32) are angled from the base (34) in the same direction at opposite end edges of the base (34) so ​​that the two antenna surfaces (30, 32) and the base (34) encompass an interior space from three sides, - with an antenna winding (46), characterized by - a guide body (64) which bears with a guide surface (68) against a surface of the base (34) facing the interior. [2] Antenna (18) according to claim 1, wherein the antenna winding (46) has at least one first single-layer spiral coil (48) which is arranged, in particular attached, on the outside of the first antenna surface (30) so that an axis (49) of the first spiral coil (48) is oriented perpendicularly with respect to the first antenna surface (30). [3] Antenna (18) according to claim 1 or 2, with a second single-layer spiral coil (56) which is arranged on the outside of the second antenna surface (32), in particular is attached, so that an axis (49) of this second spiral coil (56) is aligned perpendicularly with respect to the second antenna surface (32). [4] Antenna (18) according to one of claims 1 to 3, wherein the two antenna surfaces (30, 32) are each widened relative to the base (34), in particular have a circular widening (26). [5] Antenna (18) according to one of claims 1 to 4, wherein the two antenna surfaces (30, 32) and the base (34) are formed by a one-piece foil blank of the magnetic foil (22). [6] Antenna (18) according to one of claims 1 to 4, wherein the two antenna surfaces (30, 32) and the base (34) are formed by two foil blanks of the magnetic foil (22) each projecting into the region of the base (34). [7] Antenna (18) according to one of claims 1 to 6, wherein the guide body (64) is provided in the region of the front edges of the base (34) on the guide surface (68) with a convex guide radius for guiding the magnetic foil (22). [8] Antenna (18) according to one of claims 1 to 7, wherein the guide body (64) has at least one centering projection (78) projecting from the guide surface (68) which engages in a corresponding notch or a corresponding hole of the base (34) for positioning the base (34). [9] Antenna (18) according to one of claims 5 to 8, wherein the or each foil blank in the region between one of the two antenna surfaces (30, 32) and the base (34) has a predetermined bending point (82) in which the magnetic foil (22) is locally weakened by at least one depression (84), in particular produced by material removal by means of laser radiation. [10] Antenna (18) according to claim 9, wherein the or each recess (84) is formed on the inner side of the magnetic foil (22) facing the interior space. [11] Antenna (18) according to one of claims 6 to 10, wherein each of the two foil blanks (92, 94) has one of the two antenna surfaces (30, 32) and at least one tab (96) of the magnetic foil (22) projecting from the edge of the respective antenna surface (30, 32), and wherein to form the base (34) the or in each case one tab (96) of one of the two foil blanks (92, 94) is placed in an overlapping manner on the or in each case one corresponding tab (96) of the other foil blank (94; 92). [12] Antenna (18) according to claim 11, wherein the magnetic foil (22) of the two foil blanks (30, 34) is formed from a magnetizable layer which is enclosed on both sides by a plastic layer, and wherein one of the plastic layers is removed in the or each overlap region of the corresponding tabs (96) so that the corresponding tabs (96) each lie directly on top of one another with the magnetizable layer. [13] Hearing instrument (2) with an antenna (18) according to one of claims 1 to 12. [14] Hearing instrument (2) according to claim 13, with a functional component, in particular a battery (10) or a receiver (8), wherein the functional component has a housing (54) made of an electrically conductive material with low magnetic permeability, in particular of copper, aluminum or a steel sheet, and wherein the antenna (18) is placed on the functional component in such a way that the housing (54) flanks the antenna surfaces (30, 32) on the inside.

Images