Hearing devices and circuit boards for hearing devices

Abstract

The invention relates to a hearing instrument (2) having a battery module (14), wherein the battery module (14) has a secondary battery (16), wherein the battery module (14) has a receiving coil (18) for contactlessly charging the secondary battery (16), wherein the battery module (14) has a printed circuit board (24), which has a conductor track (26), which forms the receiving coil (18), wherein the printed circuit board (24) has a plurality of layers (30, 32), wherein the conductor track (26) extends over the plurality of layers (30, 32), and wherein each of the plurality of layers (30, 32) has a conductor loop (34) having at least one turn (36). The invention also relates to a corresponding printed circuit board (24).

Description

Technical Field

[0001] The present invention relates to a hearing device and a circuit board for a hearing device. Background Art

[0002] Hearing devices are typically used to output audio signals to the user of the hearing device. This output occurs via an output transducer, typically via airborne sound in an acoustic path via so-called earpieces (also known as loudspeakers or receivers). A special design of a hearing device is a hearing assistance device, also referred to as a hearing aid, which is used to accommodate users with hearing impairments. To this end, a hearing device typically has at least one acoustic input transducer (usually a microphone) and a signal processor. The signal processor is configured to process the input signal generated by the input transducer from ambient sound and thereby at least partially compensate for the user's hearing impairment. In particular, in the case of hearing aids, variations are also possible in which the output transducer is a so-called bone conduction earpiece or cochlear implant, which mechanically or electrically couples the audio signal into the user's auditory organ. The general term "hearing device" also includes, in particular, devices such as so-called tinnitus maskers, headphones, and headphone headsets.

[0003] To supply energy to the electronic components of hearing instruments, in particular output converters, signal processors, etc., it is advantageous to use rechargeable energy storage devices, in particular in the form of secondary batteries (also known as "accumulators"). In principle, it is conceivable to replace conventional battery specifications with secondary batteries of the same specifications. However, since secondary batteries often output different voltage values, converter electronics are usually required as part of the hearing instrument to achieve the voltage values ​​required by the electronic components, making simple replacement generally impossible. Furthermore, it should be possible to recharge the secondary battery without removing it from the respective hearing instrument, in order to increase user comfort. Since hearing instruments are often worn on the body and are therefore exposed to body fluids, in particular sweat, contactless and, in particular, wireless charging is also desirable, so that the housing of the hearing instrument can be designed to be particularly insensitive to environmental influences, in particular moisture-proof.

[0004] Contactless charging can be performed inductively using a charging coil in the hearing instrument. During charging operation, this charging coil is inductively coupled to a transmitting coil that is part of a charging device for the hearing instrument. “Contactless” is generally understood to mean that charging does not require a galvanic connection between the charging device and the hearing instrument. However, a simple mechanical coupling is possible, for example, to secure the hearing instrument to the charging device, particularly during charging. The charging coil is also referred to as a “receiving coil” or “secondary coil,” and the transmitting coil as a “primary coil.” However, in addition to the converter electronics already described, charging electronics for controlling the charging process may also be required as part of the hearing instrument. These charging electronics are often combined with a secondary battery in a so-called battery module of the hearing instrument.

[0005] For inductive charging, the most precise possible relative alignment of the charging coil with respect to the transmitting coil is desirable. Furthermore, the two coils should be positioned as close to one another as possible, for example, a few millimeters, for example, 3 millimeters. Otherwise, the energy yield during energy transfer is impaired, resulting in long charging cycles or inadequate charging. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to improve the contactless charging of secondary batteries in hearing instruments.

[0007] According to the present invention, this technical problem is solved by a hearing device having the features according to the present invention and by a printed circuit board having the features according to the present invention. Furthermore, this technical problem is solved in particular by a battery module having such a printed circuit board and for such a hearing device. Advantageous embodiments, developments, and variants are the subject matter of the present invention. In this sense, the embodiments described with respect to the hearing device also apply to the printed circuit board and the battery module, and vice versa.

[0008] The hearing device includes a battery module. The battery module is housed, in particular, in a housing of the hearing device. The battery module includes a secondary battery, which is used, in particular, to supply energy to one or more components of the hearing device. The battery module also includes a receiving coil for contactlessly charging the secondary battery. Therefore, the receiving coil is also referred to as a charging coil.

[0009] “Contactless” is generally understood to mean that charging does not require a galvanic connection between the charging device and the hearing instrument. A simple mechanical coupling is possible, for example, for the purpose of fixing the hearing instrument to the charging device, particularly during charging. Contactless charging is preferably carried out during the charging operation of the hearing instrument using an inductive resonant charging method via a magnetic field, so that the contactless charging is inductive charging. A charging device with a transmitting coil (which is also called a “primary coil”) is used for contactless charging. Correspondingly, the receiving coil is also called a “secondary coil”. The receiving coil and the transmitting coil are each also generally referred to as a coil. During the charging process, energy is transferred from the charging device to the hearing instrument via the coil, and in this way the secondary battery is charged.

[0010] During normal use, at least the housing, and preferably even the entire hearing device, is worn completely in the head area of ​​the user, preferably at the side of the head and in, on, or behind the ear. Hearing devices are correspondingly compact, which places corresponding demands on the hearing device and its individual components, namely a design that is as compact as possible and the most efficient use of installation space possible.

[0011] The battery module also has a circuit board with conductor tracks that form the receiving coil. A circuit board is also called a printed circuit board or printed circuit board (PCB for short). The conductor tracks are made, in particular, of an electrically conductive material, preferably copper, and are applied to the substrate of the circuit board, embedded in the substrate, or both.

[0012] The printed circuit board also has multiple layers, with individual layers also being referred to as coatings. The term "layer" particularly denotes a single surface carrying one or more conductor tracks. The printed circuit board is therefore a multilayer printed circuit board having at least two layers. For example, the top and bottom of the printed circuit board may each form a layer, making the printed circuit board a double-sided printed circuit board. Alternatively, the printed circuit board may have more than two layers and be a so-called multilayer printed circuit board. These layers are stacked one on top of another in a stacking direction. The printed circuit board is generally flat, i.e., plate-shaped, and preferably has a thickness in the range of 0.5 mm to 5 mm. The thickness of the printed circuit board is measured in the stacking direction, i.e., perpendicular to the layers. The printed circuit board may be flat or curved, and therefore does not necessarily extend along a single, flat surface, but may, depending on the design of the hearing device, follow a curved or angled path, for example, in order to adapt to contours in or on a housing or component of the hearing device. The printed circuit board is particularly preferably flexible, i.e., bendable and elastic, so as to, for example, follow a curved path.

[0013] The conductor tracks extend over multiple layers, and in each of these layers, a conductor loop with at least one turn is provided. This forms a receiving coil with a corresponding number of turns. The specific dimensions and arrangement of the turns determine the transmission characteristics of the receiving coil. Preferably, the conductor loops of different layers are largely similar in design, and more preferably, are largely identical when viewed in the stacking direction. "Mostly" is particularly understood to mean "at least 90%." Like the printed circuit board, the conductor tracks are preferably flexible and, for this purpose, are particularly designed as flat tracks.

[0014] The turns are characterized in that they extend completely within a single layer. Furthermore, the turns are characterized in that they form an open ring, i.e., they particularly completely enclose the free space (i.e., the interior area) as completely as possible, but are not closed. The respective turns thus have two ends that are not connected to one another, but preferably lie laterally adjacent to one another within the layer. The turns are preferably rectangular, but can alternatively be circular or have other shapes.

[0015] The core concept of the present invention lies in the use of a printed circuit board with a specially designed conductor track. The conductor track is designed as a coil by forming multiple conductor loops distributed across different layers of the printed circuit board. This allows for a simple and compact implementation of a receiving coil for contactless charging. Due to its particularly flat design, the use of the conductor track as a receiving coil results in a particularly advantageous form factor. The receiving coil is generally very flat, often flatter than a coil wound from wire with similar transmission characteristics. In particular, the printed circuit board avoids overlap at the ends of the conductor track, which results in thickening, as is the case with coils made from wire, where one of the wire ends must be guided outward from the coil interior for connection. Furthermore, the printed circuit board's conductor tracks can be reproducibly manufactured with exceptionally high precision and are therefore particularly suitable for high-volume production. Typically, the conductor tracks can be reproducibly manufactured with tolerances of less than 10 μm. In comparison, the production of hand-wound coils, for example, is significantly less precise, with greater deviations between the coils. However, machine-wound coils sometimes exhibit greater deviations from one another than when conductor lines are manufactured. Therefore, two coils manufactured similarly from metal wire do not necessarily have identical transmission characteristics. This also results in different resonant frequencies. To compensate for this, tuning capacitors can be used, which then correct the resonant frequency. However, this requires additional components and is more complex, as the required capacitance and corresponding capacitors must be determined and selected for each coil. This negatively impacts production costs and speed.

[0016] Preferably, the conductor loops together form a spiral, and the turns of the corresponding conductor loops form a meander, so that the receiving coil is constructed as a spiral coil of a meander plane. The turns of the corresponding conductor loops form a meander within the corresponding layer. A spiral is formed by extending the conductor line over multiple layers. Therefore, in general, multiple meanders are arranged one on top of the other in the stacking direction and are connected in series with each other so as to form a spiral. To this end, one of the two ends of the corresponding meander is connected to one end of the meander of the conductor loop located above it, and the other of the two ends is connected to one end of the meander of the conductor loop located below it. In order to construct the spiral, at least two conductor loops, i.e. two layers, are required. In order to construct the meander, at least two turns are required within one layer. The spiral design of the meander plane of the coil combines the advantages of a particularly large inductance on the one hand and a particularly compact structural form on the other.

[0017] In a particularly preferred embodiment, the receiving coil has exactly two conductor loops, each with exactly two turns, resulting in a total of four turns, distributed over two layers. This embodiment is particularly suitable for hearing aids. Furthermore, with only two layers, production is particularly simple by simply forming the conductor loops on the top and bottom of the printed circuit board.

[0018] The conductor loops are preferably electrically conductively connected and connected in series via plated through-holes. Plated through-holes are also referred to as "through-holes." These are typically embedded in the substrate of the printed circuit board, for example as holes with metallized inner walls or with metal sleeves mounted therein, and extend from one layer to an adjacent layer. The plated through-holes extend, in particular, in the stacking direction and therefore perpendicular to the layers. Two conductor loops are each electrically conductively connected to a plated through-hole, resulting in a series connection of the conductor loops overall. The number of plated through-holes is then one less than the number of conductor loops.

[0019] Based on the turns, the respective conductor loops have, in particular, inner and outer ends, and the two inner ends or the two outer ends are always connected to one another via corresponding plated-through holes. The two remaining ends of the uppermost and lowermost conductor loops are connected to respective connection contacts for connecting the coils, for example, to a secondary battery, converter electronics, charging electronics, or a combination thereof.

[0020] Typically, the printed circuit board has two connection contacts, each of which is connected to one end of a conductor track in order to connect the receiving coil. The connection contacts are preferably arranged together in one of several layers of the printed circuit board. In particular, for this purpose, at least one of the connection contacts has a plated through-hole that connects it to the end of a conductor track in another layer.

[0021] Preferably, the hearing instrument has charging electronics for controlling the charging process of the secondary battery. In a suitable embodiment, the hearing instrument alternatively or additionally has converter electronics for voltage conversion in order to achieve suitable voltage values ​​for the electronic components. The charging electronics or the converter electronics or both are in particular implemented as an integrated circuit or circuit, or in a similar manner as part of a circuit board and thus as part of the battery module.

[0022] Preferably, the conductors have a width in the range of 200 μm to 500 μm and a thickness in the range of 10 μm to 100 μm. These dimensions result in particularly suitable transmission characteristics. Preferably, the conductors have a rectangular cross-section, wherein the width is measured along the layers and the thickness is measured perpendicular to the layers.

[0023] The following Table 1 describes six advantageous embodiments AF of the receiving coil and their transmission characteristics which have been determined using simulations:

[0024]

[0025]

[0026] Table 1

[0027] All six designs AF according to Table 1 have a conductor track with four turns. In design F, each turn is arranged in its own layer, whereas in designs AE, two layers are formed, each layer having a conductor loop with two turns. The conductor track width is 0.3 mm for designs A, B, C, and F, and 0.4 mm for the other designs. In designs AE, the conductor track thickness is the same for all corresponding conductor loops, whereas in design F, the conductor loops in the two middle layers are thinner than those in the outer layers. The last column indicates the Q factor, or quality factor, of the receiving coil. The Q factor, "Q" for short, also determines the quality of the coupling between the two coils.

[0028] The Q factor is related to the dimensions of the conductor line. In particular, the conductor line has a characteristic that determines the resistance of the conductor line, more precisely the AC resistance (English: AC resistance, R AC denoted by ). A reduction in cross section generally leads to an increase in resistance. Therefore, in principle, a large cross section, i.e., a large width, is advantageous, since the thickness can generally be selected less flexibly than the width, depending on the layer structure and the production of the circuit board. The cross section results from the product of width and height, for example, as described in Table 1 above. Resistance R AC is frequency dependent and is given by the following equation:

[0029] R AC (f) = [(2.16 × 10 -7 )√(f·ρ R )] / [2(w+d)]

[0030] Here, w is the width, d is the thickness of the conductor line, f is the frequency in Hz, and ρ R is the relative resistivity of the conductor line compared to copper, where ρ R = 1. However, with the same outer dimensions of the conductor loop, a smaller width results in a larger free surface area surrounded by the conductor loop and, therefore, a greater inductance of the coil. Accordingly, a trade-off must be made between the lowest possible resistance on the one hand and the highest possible inductance on the other.

[0031] As can be seen from Table 1 above, with the same thickness but different widths, a greater inductance and a higher resistance result for the configuration with the smaller width, see for example configurations A and D or B and E. However, the difference in the Q factor is not significant here.

[0032] According to Table 1, different thicknesses in otherwise identical designs result in a lower inductance for the smaller thickness, but a significantly higher resistance, which in combination has a significant impact on the Q factor. Therefore, the greatest possible thickness is preferred, as this leads to a higher Q factor, as seen in designs A, B, and C, for example.

[0033] Finally, Table 1 shows that the designs with two layers (designs AE) are superior to the designs with four layers (design F) because they result in a larger Q factor. Furthermore, designs with fewer layers also advantageously have lower production costs and are therefore also preferred.

[0034] Similar to Table 1 above, Table 2 below shows three receive coil designs and their parameters, particularly the Q factor. However, the data presented is based on measurements on a manufactured circuit board prototype rather than simulations. The designations A, B, and C in Table 2 are unrelated to those in Table 1.

[0035] Design Width [mm] thickness Inductance [nH] Resistance [mΩ] Q A 0.3 2oz / 70μm 127.84 334.29 32.58 B 0.4 1oz / 35μm 119.15 424.78 23.90 C 0.4 2oz / 70μm 99.85 34.7 34.70

[0036] Table 2

[0037] Compared to Table 1, the actual measured values ​​in Table 2 also take into account manufacturing parameters, such as the purity of the copper used to make the conductor tracks, the material of the printed circuit board, etc. Furthermore, in each of the designs in Table 2, a ferrite layer is also present, more precisely in an intermediate position, as will be explained in more detail below. All three designs A, B, and C have two conductor loops in two layers, with two turns per conductor loop, for a total of four turns. The significant influence of thickness and the negligible influence of width are clearly visible. Designs A and C are generally preferred due to the Q factor, with design C being particularly preferred.

[0038] The circuit board advantageously has an additional ferrite layer that completely covers the conductor loop to increase the inductance of the receiving coil. The ferrite layer is preferably composed of ferrite and is connected to the other layers, for example, by means of an adhesive, such as an adhesive layer, i.e., bonded to one of the layers, to another layer, or to the substrate of the circuit board. The ferrite layer is preferably bonded to the outer layers of the layers, thereby forming a closed element in the stacking direction, so that the receiving coil is completely arranged on only one side of the ferrite layer. The ferrite layer is preferably arranged on the side of the receiving coil that faces away from the transmitting coil during contactless charging. The ferrite layer is thus not arranged directly between the two coils.

[0039] The ferrite layer serves to strengthen the magnetic field generated by the transmitting coil during contactless charging and to increase the magnetic flux density in the surrounding area of ​​the ferrite layer. Therefore, the ferrite layer is preferably placed in close proximity to the receiving coil in order to deflect and concentrate the magnetic field in its direction and thereby achieve better coupling with the transmitting coil. The ferrite layer also influences the Q factor, which is determined, among other things, by the material of the ferrite layer. The so-called loss tangent serves as a measure of the energy loss generated by the magnetic material of the ferrite layer. The loss tangent is inversely proportional to the Q factor and is defined by the following equation:

[0040] tanδ=1 / Q=μ" / μ'

[0041] Here, "tanδ" is the loss tangent, μ" is the imaginary part of the complex-valued relative permeability, and μ' is the real part of the complex-valued relative permeability. From the above equation, it can be seen that lower losses lead to a higher Q factor, that is, to better transmission characteristics. The loss tangent is generally frequency-dependent. The receiving coil has a resonant frequency, preferably a resonant frequency of 13.56 MHz. The resonant frequency is used to transmit energy. In particular, the transmitting coil has the same resonant frequency as the receiving coil. At the resonant frequency, the losses should be as low as possible, that is, in particular, the loss tangent for the resonant frequency is preferably less than 0.02. The selection of the material for the ferrite layer is carried out in particular according to the aforementioned boundary condition, that is, the ferrite layer consists of a material that has a loss tangent of at most 0.02 at the resonant frequency of the receiving coil.

[0042] The ferrite layer is preferably also flexible.

[0043] In general, the larger the size of the ferrite layer, the greater the inductance of the receive coil. In any case, it is advantageous for the ferrite layer to completely, not only partially, cover the conductor loop and the entire receive coil. This is based on the observation that different positions of the ferrite layer relative to the receive coil result in different inductances. This is illustrated in Table 3 below, which shows the inductances for different positions relative to the center position. The positions are specified as displacements in the X and Y directions perpendicular to the stacking direction, which also corresponds to the Z direction. In the center position, the center point of the ferrite layer and the conductor loop lies along a straight line in the stacking direction, and the ferrite layer extends perpendicular to the stacking direction, i.e., in the X and Y directions, at least to the conductor loop, completely covering it. In Table 3, the center position is achieved in Design A, which also shows the highest inductance. Designs A and B of the conductor tracks according to Table 3 are independent of the designs in Tables 1 and 2 and are essentially independent.

[0044]

[0045]

[0046] Table 3

[0047] The X and Y displacement in embodiment BI according to Table 3 has the result that the ferrite layer no longer completely covers the conductor loop and therefore does not exert an optimal influence on the magnetic field.

[0048] In an advantageous embodiment, the printed circuit board has a recess within the conductor loop, and the ferrite layer has a protrusion that projects into the recess, so that the protrusion is arranged within the turns and forms a ferrite core for the receive coil. The protrusion is also called a "punch" because it protrudes from the other ferrite layers in the stacking direction and forms a stepped surface that projects into the free space within the conductor loop. The protrusion typically provides the ferrite layer with more material, thereby further increasing the density of the magnetic field, particularly in the center of the receive coil. This further improves the coupling of the coil. For example, the recess is cut into the printed circuit board and preferably extends completely through it, so that it forms a hole in the circuit board. The protrusion of the ferrite layer typically has a circumferential contour that typically follows the inner contour of the conductor loop, so that the available free space is optimally utilized and filled with the ferrite layer.

[0049] The secondary battery is preferably cylindrical and has an outer surface, and the printed circuit board and the receiving coil are curved and follow the outer surface. Advantageously, the printed circuit board is flexible, as already described, and thus correspondingly bendable. For example, the secondary battery is designed in the manner of a button cell and is therefore generally cylindrical. Cylindrical secondary batteries typically extend longitudinally along a longitudinal axis. The outer surface surrounds the longitudinal axis and encloses the secondary battery in a radial direction perpendicular to the longitudinal direction. The printed circuit board preferably extends in a curved manner, such that it also curves around the longitudinal axis of the secondary battery. The stacking direction of the printed circuit boards thus corresponds to the radial direction. The receiving coil is correspondingly curved. This allows the printed circuit board to be arranged in a particularly space-saving manner. The preferred radial arrangement is advantageous compared to arranging the printed circuit board on the end face of the secondary battery because it allows for greater freedom in the design and positioning of the receiving coil.

[0050] A shielding layer, preferably made of copper, is advantageously arranged between the circuit board and the secondary battery. The shielding layer serves to reduce the overall resistance of the secondary battery and also to minimize the influence of the skin effect. Secondary batteries typically have a particularly high relative permittivity and generate strong eddy currents through interaction with magnetic fields. This, in particular, also increases the temperature of the secondary battery. Overall, a preferred arrangement, viewed radially from the inside out, results in the secondary battery being arranged on the inside, followed by the shielding layer, then the ferrite layer (if present), and finally the circuit board with the receiving coil. Finally, the housing of the hearing instrument is also located further outward.

[0051] The hearing device is preferably a BTE hearing aid, i.e., a behind-the-ear hearing aid (BTE = behind the ear), or a RIC hearing aid, i.e., a hearing aid with the earpiece worn in the ear canal (RIC = receiver in canal). In the case of BTE and RIC hearing aids, the housing is worn by the user behind the ear, rather than inside the ear (as in ITE hearing aids). In the case of a BTE hearing aid, the earpiece for sound output is arranged in the housing, and a sound hose is guided from the housing to the user's ear when the hearing aid is worn. In contrast, in the case of a RIC hearing aid, the earpiece for sound output is arranged outside the housing and, when the hearing aid is worn, is placed in the ear canal. The earpiece is connected to the housing via an electrical lead. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings.

[0053] Figure 1 A hearing device and a charging device are shown;

[0054] Figure 2 Shown Figure 1 A battery module for a hearing device having a circuit board;

[0055] Figure 3 Shown Figure 2 The first layer of the circuit board;

[0056] Figure 4 Shown Figure 2 The second layer of the circuit board;

[0057] Figure 5 Shown Figure 2 Conductor lines of a circuit board;

[0058] Figure 6 The coil is shown;

[0059] Figure 7 A combination of the "zigzag" and "spiral" approaches is shown for forming a zigzag, flat, spiral coil;

[0060] Figure 8 Shown in detail Figure 2 A fragmentary diagram of a battery module;

[0061] Figure 9 Other battery modules are shown, which have Figure 6 of the coil. DETAILED DESCRIPTION

[0062] Figure 1 A hearing device 2 is shown for outputting audio signals to a user (not shown). The output takes place here by means of an output transducer, in this case via airborne sound in an acoustic path, by means of a so-called earpiece 4. In the embodiment shown here, the hearing device 2 is a hearing assistance device, also referred to as a hearing aid, for accommodating a user with a hearing impairment. To this end, the hearing device 2 has at least one acoustic input transducer (here, two microphones 6) and a signal processor 8. The signal processor 8 is designed to process the input signal generated by the input transducer from the ambient sound and thereby at least partially compensate for the user's hearing impairment. The hearing device 2 has a housing 10 in which various components are housed. However, the following embodiments are generally also applicable to hearing devices 2 that are not specifically hearing aids.

[0063] Figure 1The hearing device 2 shown is specifically a RIC hearing aid, i.e. a hearing aid in which the earpiece 4 is worn in the ear canal (RIC = receiver in canal). In a variant not explicitly shown, the hearing device 2 is a BTE hearing aid, i.e. a behind-the-ear hearing aid (BTE = behind the ear). In BTE hearing aids and RIC hearing aids, the housing 10 is worn by the user behind the ear instead of in the ear (as in ITE hearing aids). In a BTE hearing aid, the earpiece 4 for sound output is arranged in the housing 10, and a sound hose is led from the housing 10 to the ear of the user in the worn state. In contrast, in the case of a RIC hearing aid, the earpiece 4 for sound output is arranged outside the housing 10, as in Figure 1 As can be seen in FIG, and in the wearing state is placed in the auditory canal. The earpiece 4 is connected to the housing 10 via an electrical line 12.

[0064] The hearing device 2 has a battery module 14 which Figure 1 are shown only in a highly schematic manner. Figure 2 An embodiment of a battery module 14 is shown in detail. The battery module 14 is accommodated in the housing 10 and comprises a secondary battery 16 for supplying energy to one or more components of the hearing device 2. The battery module 14 also comprises a receiving coil 18 for contactlessly charging the secondary battery 16. The receiving coil 18 is therefore also referred to as a charging coil.

[0065] Currently, contactless charging is performed in the charging mode for the hearing instrument 2 by means of a magnetic field using an inductive resonance charging method. The charging device 20 for contactless charging has a transmitting coil 22, which is also referred to as a "primary coil". Figure 1 An example of this can be seen in a greatly simplified form in . Accordingly, the receiving coil is also referred to as the "secondary coil." The receiving coil 18 and the transmitting coil 22 are each often also referred to as a coil. During charging, energy is transferred from the charging device 20 to the hearing instrument 2 via the coils 18 , 22 , thereby charging the secondary battery 16 .

[0066] The battery module 14 also has a circuit board 24, which is also already Figure 1 is shown simplified in Figure 2 . The circuit board 24 has conductor tracks 26 that form the receiving coil 18. The circuit board 24 is also called a printed circuit board or printed circuit board (PCB for short). The conductor tracks 26 are made of an electrically conductive material (here, copper) and are applied to or embedded in a substrate 28 of the circuit board, or contain both.

[0067] The circuit board 24 has a plurality of layers 30, 32, wherein the individual layers 30, 32 (English: layer) are also referred to as coatings. The term "layer" particularly denotes an individual surface carrying one or more conductor tracks. The circuit board 24 is therefore a multilayer circuit board 24 having at least two layers 30, 32. For example, Figure 3 The upper side 30 shown and the Figure 4 The bottom sides 32 shown form layers 30, 32, respectively, so that the circuit board 24 is a double-sided circuit board 24. In a variant not explicitly shown, the circuit board 24 has more than two layers 30, 32 and is a so-called multilayer circuit board 24. The layers 30, 32 are stacked on top of each other in the stacking direction S. Figures 2 to 4 As can be seen, the circuit board 24 is generally flat, i.e., plate-shaped. The circuit board 24 can be flat or curved, and therefore does not necessarily extend along a single flat plane, but may follow a curved path depending on the design of the hearing device, for example, in order to adapt to contours in or on a housing or component of the hearing device, as in Figure 2 As can be seen in . Figure 3 and Figure 4 The plane diagrams show Figure 2 The circuit board 24 shown here is also flexible, i.e. bendable and elastic, so that it can be bent and resilient as shown in FIG. Figure 2 As shown in FIG, the curve follows.

[0068] The conductor track 26 extends over a plurality of layers 30, 32 and in each of the plurality of layers 30, 32 has a conductor loop 34 with at least one turn 36. In this way, a receiving coil 18 is formed which has a corresponding number of turns 36. A suitable design of the conductor track 26 can be obtained from Figure 3 and Figure 4 as well as Figure 5 Seen in Figure 5 Shown in a three-dimensional diagram Figure 3 and Figure 4 The conductor lines 26 are not shown and the substrate 28 is not shown. Figure 5 The multi-layered structure of the conductor tracks 26 on multiple planes of the circuit board 24 is clearly visible. The specific dimensions of the turns 36 and their arrangement determine the transmission characteristics of the receiving coil 18. In the exemplary embodiment shown, the two conductor loops 34 of different layers 30, 32 are largely similar in design and, moreover, are largely identical even when viewed in the stacking direction S, as shown in particular in FIG. Figure 5 Like the printed circuit board 24 , the conductor tracks 26 are also flexible and, for this purpose, are designed as flat tracks.

[0069] As in Figures 3 to 5As can be seen in FIG, the turns 36 are characterized by extending completely within the individual layers 30, 32. Furthermore, the turns 36 are characterized by forming an open ring, i.e., they completely enclose the free space 38, i.e., the interior area, as completely as possible, but are not closed. Thus, each turn 36 has two ends 40, 41, which are not connected to one another but are laterally adjacent to one another. Furthermore, the turns 36 are also rectangular in shape here, but other shapes are generally suitable.

[0070] Due to the flat design, the use of the conductor line 26 as the receiving coil 18 results in a favorable form factor, wherein the receiving coil 18 is designed to be flatter than a coil 42 wound from a metal wire with similar transmission characteristics, such as Figure 6 In particular, what is avoided in the printed circuit board 24 is that the end-side overlap of the conductor tracks leads to thickening, as in Figure 6 This is the case for a coil 42 made of wire, in which case one of the wire ends must be guided outward from the interior of the coil 42 for connection, thereby forming an overlap 44 .

[0071] exist Figures 3 to 5 In the embodiment of FIG, the conductor loops 34 together form a spiral 46, and the turns 36 of the respective conductor loops 34 form a meander 48, so that the receiving coil 16 is designed as a meander-shaped spiral coil. Figure 7 The basic concept is illustrated in FIG. The turns 36 of the respective conductor loops 34 form a meander 48 within the respective layer 30 , 32 . The conductor line 34 extends over a plurality of layers 30 , 32 , thereby forming a spiral 46 . Thus, overall, a plurality of meanders 48 are arranged one above the other in the stacking direction S and are connected in series with one another, so that a spiral 46 is formed. For this purpose, the meanders 48 of adjacent layers 30 , 32 are connected to one another at the end sides. At least two conductor loops 34 , i.e., two layers 30 , 32 , are required to form the spiral 46 . At least two turns 36 are required within a layer 30 , 32 to form the meander 48 .

[0072] In the embodiment shown here, the receiving coil 18 has exactly two conductor loops 34, each of which has exactly two turns 36, so that there are a total of four turns 36, which are distributed over two layers 30, 32. The printed circuit board 24 is manufactured, for example, in such a way that a conductor loop 34 is formed on the upper side 30 and the lower side 32 of the printed circuit board 24, as shown in FIG. Figure 3 and Figure 4 As shown in .

[0073] In this case, the conductor loops 34 are electrically conductively connected by means of plated through-holes 49 (also referred to as “through-holes”) and are connected in series. Figure 5, are clearly visible in the figure and are embedded in the base 28 of the circuit board 24 and extend from one layer 30 to the adjacent layer 32. Here, the plated-through holes 49 extend in the stacking direction S and therefore extend perpendicularly to the layers 30, 32. Two conductor loops 34 are each electrically conductively connected to the plated-through holes 49, so that a series connection of the conductor loops 34 is produced as a whole. Based on the turns 36, the corresponding conductor loop 34 has an inner end 40 and an outer end 41, and the two inner ends 40 or the two outer ends 41 are always connected to each other by means of the corresponding plated-through holes 49. The two remaining ends 40, 41 of the uppermost and lowermost conductor loops 34 are connected to each connection contact 50 for connecting the coil 18, for example, to the secondary battery 16, the converter electronics 52, the charging electronics 54 or a combination thereof. Typically, the circuit board 24 has two connection contacts 50, each of which is connected to one end of the conductor line 26 in order to connect the receiving coil 18. In the embodiment shown, the connection contacts 50 are as shown in Figure 5 As can be seen in FIG, they are arranged together in layer 30 of printed circuit board 24 , for which purpose a plated-through hole 56 is present for at least one of the connecting contacts 50 , which connects this connecting contact 50 to the end of the conductor track 26 in the other layer 32 .

[0074] The hearing device 2 has charging electronics 54 for controlling the charging process of the secondary battery 16. Alternatively or additionally, the hearing device 2 has converter electronics 52 for voltage conversion in order to achieve a suitable voltage value for the electronic components. The charging electronics 54 or the converter electronics 52 or both are connected to the secondary battery 16. Figure 2 The battery module 14 is implemented as an integrated circuit or circuit, or in a similar manner as part of the circuit board 24 and thus as part of the battery module 14.

[0075] In the exemplary embodiment shown, the conductor 26 has a width w in the range of 200 μm to 500 μm and a thickness d in the range of 10 μm to 100 μm. These dimensions result in suitable transmission characteristics. In the present case, the conductor 26 also has a rectangular cross-section, wherein the width w is measured along the layers 30 , 32 and the thickness d is measured perpendicular to the layers 30 , 32 .

[0076] Optionally, the circuit board 24 has an additional ferrite layer 58 which completely covers the conductor loop 34 in order to increase the inductance of the receiving coil 18. Figure 2 An embodiment with a ferrite layer is shown in . Figure 8 Shown Figure 2, in which the conductors 26 and the ferrite layer 58 are particularly clearly visible. The ferrite layer 58 is composed, in particular, of ferrite and is currently connected to the other layers 30, 32 by means of an adhesive. The ferrite layer 58 is bonded to the outer layers 30, 32 and thus forms a closure in the stacking direction S, so that the receiving coil 18 is completely situated on only one side of the ferrite layer 58. Here, the ferrite layer 58 is situated on the side of the receiving coil 18 that faces away from the transmitting coil 22 during contactless charging. Consequently, the ferrite layer 58 is not situated precisely between the two coils 18, 22.

[0077] The ferrite layer 58 is used to strengthen the magnetic field generated by the transmitting coil 22 during contactless charging and to increase the magnetic flux density in the surroundings of the ferrite layer 58. Figure 2 and Figure 8 As shown, a ferrite layer 58 is positioned in close proximity to the receiving coil 18 in order to deflect and concentrate the magnetic field in its direction. The receiving coil 18 has a resonant frequency for energy transmission. The transmitting coil 22 has the same resonant frequency as the receiving coil 18. At the resonant frequency, losses should be as low as possible. The material for the ferrite layer 58 is then selected based on the appropriate boundary conditions. The ferrite layer 58 is also preferably flexible.

[0078] In the embodiment shown, the ferrite layer 58 completely, ie not only partially, covers the conductor loop 34 and the entire receiving coil 18. If the ferrite layer 58 were to move, the conductor loop 34 would no longer be completely covered and an optimum effect of the magnetic field would no longer be achieved.

[0079] As from Figure 8 As can be seen in FIG, in the embodiment shown there, the printed circuit board 24 has a recess 60 in the conductor loop 34, and the ferrite layer 58 has a ridge 62 which projects into the recess 60, so that the ridge 62 is arranged in the turns 36 and forms a ferrite core for the receiving coil 18. The ridge 62 is also called a "punch" because it projects from the other ferrite layers 58 in the stacking direction S and forms a stepped surface which projects into the free space 38 in the conductor loop 34. In addition, according to Figure 8 The elevation 62 of the ferrite layer 58 has a circumferential contour U which generally follows the inner contour I of the conductor ring 34 , so that the available free space 38 is optimally utilized and filled with the ferrite layer 58 .

[0080] The secondary battery 16 shown here is cylindrical and has an outer surface 64. The circuit board 24 and the receiving coil 18 are curved and follow the outer surface 64, as shown in particular in FIG. Figure 2As can be seen in . The cylindrical secondary battery 18 generally extends in the longitudinal direction along the longitudinal axis L. The outer cover surface 64 extends around the longitudinal axis L and surrounds the secondary battery 18 in a radial direction R perpendicular to the longitudinal direction. The circuit board 24 now extends in a curved manner so that it is also curved around the longitudinal axis L of the secondary battery 18. The stacking direction S of the circuit board 24 therefore corresponds to the radial direction R. The receiving coil 18 is curved accordingly. In this way, the circuit board 24 is arranged in a particularly space-saving manner. Compared to the arrangement of the circuit board 24 on the end face of the secondary battery 18, as in Figure 9 As exemplified in Figure 2 The radial arrangement shown is advantageous because it enables a more flexible design and positioning of the receiving coil 18. In addition, due to the flat design of the circuit board 24 relative to the coil 42, the receiving coil 18 and the circuit board 24 can be arranged together along the outer cover surface 64, which is convenient in the embodiment of the present invention. Figure 9 It is not possible to use coil 42 in the circuit.

[0081] Optionally, a shielding layer 66 is arranged between the circuit board 24 and the secondary battery 18. Figure 2 can be clearly seen in and there is exemplarily composed of copper. In general, Figure 2 , viewed from the inside outward in radial direction R, results in an arrangement with secondary battery 18 arranged inside, then shielding layer 66, then ferrite layer 58, and finally circuit board 24 with receiving coil 18. Finally, further outward there is also housing 10 of hearing instrument 2.

[0082] Reference Signs List

[0083] 2Hearing devices

[0084] 4 Earpiece

[0085] 6 microphones

[0086] 8 signal processors

[0087] 10 shell

[0088] 12 electrical conductors

[0089] 14 battery modules

[0090] 16 secondary batteries

[0091] 18 receiving coil, coil

[0092] 20 charging device

[0093] 22 Transmitting coil, coil

[0094] 24 circuit boards

[0095] 26-conductor line

[0096] 28 (circuit board) substrate

[0097] 30 upper side, layer

[0098] 32 lower side, layer

[0099] 34 Conductor ring (conductor line)

[0100] 36 turns (of the conductor ring)

[0101] 38 Free Space

[0102] 40 (turn) inner end

[0103] 41 outer end (of the turn)

[0104] 42 coils

[0105] 44 overlap

[0106] 46 spiral parts

[0107] 48 circular pieces

[0108] 49 plated through holes

[0109] 50 connection points

[0110] 52 Converter Electronics

[0111] 54 charging electronic devices

[0112] 56 plated through holes (for connecting contacts)

[0113] 58 ferrite layer

[0114] 60 recess

[0115] 62 (Rising portion of ferrite layer)

[0116] 64 (Secondary battery) outer cover

[0117] 66 shielding layer

[0118] d (conductor line) thickness

[0119] I (inner contour of the conductor loop)

[0120] L longitudinal axis

[0121] R radial direction

[0122] S stacking direction

[0123] Circumferential profile of the U (ridge)

[0124] w(conductor line) width

Claims

1. A hearing device (2) comprising a battery module (14), - wherein the battery module (14) has a secondary battery (16), -in, The battery module (14) has a receiving coil (18) for contactlessly charging the secondary battery (16). wherein the battery module (14) has a printed circuit board (24) having a conductor track (26) which forms a receiving coil (18), wherein the circuit board (24) has a plurality of layers (30, 32) which are stacked on top of one another in a stacking direction, wherein the conductor path (26) extends over a plurality of layers (30, 32) and wherein in each of the plurality of layers (30, 32) there is a conductor loop (34) having at least one turn (36), - wherein the secondary battery (16) is cylindrical and has an outer cover (64), - wherein the secondary cell (16) extends in a longitudinal direction along a longitudinal axis (L), wherein the outer cover surface (64) surrounds the longitudinal axis (L) and encloses the secondary cell (16) in a radial direction (R) perpendicular to the longitudinal direction, It is characterized in that - the circuit board (24) and the receiving coil (18) are curved and follow the outer cover (64), The printed circuit board (24) extends in a curved manner, such that the printed circuit board (24) is also curved about the longitudinal axis (L) of the secondary cell (16), so that the stacking direction (S) of the printed circuit board (24) corresponds to the radial direction (R).

2. The hearing device (2) according to claim 1, wherein The conductor loops (34) together form a spiral (46), and the turns (36) of the respective conductor loops (34) form a meander (48), so that the receiving coil (18) is designed as a meander-shaped, flat and spiral coil.

3. The hearing device (2) according to claim 1, wherein The receiving coil (18) has exactly two conductor loops (34), each of which has exactly two turns (36), so that there are a total of four turns (36), which are distributed over two layers (30, 32).

4. The hearing device (2) according to claim 1, wherein The conductor loops (34) are electrically conductively connected via plated through-holes (49) and are connected in series.

5. The hearing device (2) according to claim 1, wherein The conductor line (26) has a width (w) in the range of 200 μm to 500 μm and a thickness (d) in the range of 10 μm to 100 μm.

6. The hearing device (2) according to claim 1, wherein The circuit board (24) has an additional ferrite layer (58) which completely covers the conductor loop (34) in order to increase the inductance of the receiving coil (18).

7. The hearing device (2) according to claim 6, wherein The printed circuit board (24) has a recess (60) in the conductor loop (34), and the ferrite layer (58) has a ridge (62) extending into the recess (60), so that the ridge (62) is arranged in the winding (36) and forms a ferrite core for the receiving coil (18).

8. The hearing device (2) according to any one of claims 1 to 7, wherein The hearing device is a BTE hearing aid or a RIC hearing aid.

9. A circuit board (24) for a hearing device (2), The printed circuit board (24) has a conductor track (26), which forms the receiving coil (18), The circuit board (24) has a plurality of layers (30, 32) which are stacked on top of one another in a stacking direction, wherein: The conductor track (26) extends over a plurality of layers (30, 32) and comprises a conductor loop (34) in each of the plurality of layers (30, 32), the conductor loop having at least one turn (36). - wherein the circuit board (24) and the receiving coil (18) are curved to follow the outer surface (64) of the cylindrical secondary battery (16), The printed circuit board (24) extends in a curved manner, so that the printed circuit board (24) is also curved about a longitudinal axis (L), so that a stacking direction (S) of the printed circuit boards (24) corresponds to a radial direction (R) perpendicular to the longitudinal axis.

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