Receiver for use in ear canal

Abstract

The present invention relates to a receiver for use in an ear canal of a person, a receiver housing for such receiver and a receiver in canal assembly, wherein the receiver comprises a receiver housing having a sound outlet in acoustic communication with a first and a second front volume within the receiver housing; a first hinged diaphragm arranged within the receiver housing and separating a first front volume and a first rear volume within the receiver housing, wherein the first hinged diaphragm comprises a hinged portion and a moveable portion, and wherein a first voice coil is secured to the moveable portion of the first hinged diaphragm, to form a first diaphragm voice coil assembly, which moveable portion of the first hinged diaphragm is adapted to vibrate in response to a drive signal applied to the first voice coil; a second hinged diaphragm arranged within the receiver housing and separating a second front volume and a second rear volume within the receiver housing, wherein the second hinged diaphragm comprises a hinged portion and a moveable portion, and wherein a second voice coil is secured to the moveable portion of the second hinged diaphragm, to form a second diaphragm voice coil assembly, which moveable portion of the second hinged diaphragm is adapted to vibrate in response to a drive signal applied to the second voice coil; wherein the first and second rear volumes comprise a magnetic motor configured to generate a static magnetic field in a space within which at least part of the first and second voice coils are positioned.

Description

[0001] RECEIVER FOR USE IN EAR CANAL

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a receiver for use in an ear canal of a person, a receiver in canal assembly and a hearing device comprising such receiver in canal assembly.

[0004] BACKGROUND OF THE INVENTION

[0005] Within the hearing aid industry, the shape and dimensions of the hearing aid components forming the hearing aid devices are of great importance as these components need to fit into the hearing devices, such as hearing devices being at least partly positioned in the ear canal of the user of the hearing device. An example of such a hearing device is the In-The-Ear (ITE) hearing aid.

[0006] With respect to ITEs the shape and dimensions of the receiver are of particular importance in that the receiver needs to fit into the nozzle of the hearing device. In the hearing aid industry, the term "receiver" is commonly used to refer to a sound generating device, i.e. a speaker.

[0007] Hearing devices such as ear pods, headphones, mobile phones and the like typically include so-called dynamic speakers, wherein a linear motor is used to move a cone-shaped diaphragm. A drive signal, alternating current, is applied to a voice coil connected to the diaphragm. The voice coil moves axially in a cylindrical gap containing a magnetic field produced by a permanent magnet, due to Faraday's law of induction. This causes the diaphragm to move in air, causing sound waves. The dynamic speaker, moving coil, was first invented in 1898 and further improved in 1925, see US patent specification No. 1,707,570, which is still the same moving coil principle used in dynamic speakers today and is characterized by a relatively flat frequency response.

[0008] The rear of the speaker must be contained in a housing, to ensure that sound waves emanating from the rear of the diaphragm do not cancel out sound waves emanating from the front of the diaphragm. The rear volume is a closed volume which, consequently, has a certain stiffness. The larger the volume, the lower the stiffness. There is a direct relation between the stiffness and the output of the receiver, which means that the larger the rear volume, the lower the stiffness, the higher the sound output.

[0009] Although such dynamic speakers are, by far, the most common type of speakers used today, in contrast, in the hearing aid industry, balanced armature driver-based receivers are by far the most in use today. Balanced armature-based receivers and moving coil based receivers (dynamic speakers) use different technology principles for producing sound pressure and they differ in construction. The armature (a metal strip) in a balanced armature receiver is placed between two magnets and a fixed, non-moving, coil is placed around the armature. The armature tip is positioned exactly in the centre between two magnets (balanced armature). Current through the coil will inject flux into the armature, setting it in motion. A drive pin connected to the armature on one end moves a diaphragm on the other end producing sound pressure which is let out via a sound outlet.

[0010] Balanced armature drivers offer substantially more output per mm3and are more efficient in transforming electrical energy into sound. This means that balanced armature receivers are inherently smaller and use less power for the same or higher output, same or higher Sound Pressure Level (SPL) in dB. For example, a 4100 single balanced armature receiver marketed by Sonion A / S as the world's smallest has dimensions of 0.98 x 2.70 x 5.00 mm; a total volume of 13.2 mm2and a maximum peak output of 113 dB. The 2600 series balanced armature receiver, marketed by Sonion A / S, has dimensions of 5.25 x 3.05 x 2.55 mm; a total volume of 41 mm3; and a maximum peak output of 126 dB. The latter dimensions are sufficiently small to enable us in In the Ear (ITE) and Completely in the Canal (CIC) applications as they fit into the ear canal of a significant proportion of hearing-impaired persons, in other words, the 'fit rate' is typically above 90%. Knowles Corporation for example markets a RAB-32037-000 receiver for use in receiver in canal (RIC) applications having dimensions of 5.28 x 2.96 x 2.58 mm; a total volume of 40 mm3; and a maximum peak output of 118 dB .Larger balanced armature receivers, such as the 1900 receiver marketed by Sonion A / S, having dimensions of 7.95 x 5.60 x 4.07 mm, at a total volume of 181.2 mm3and a maximum peak output of 138 dB, are more suitable for use in so called Behind the Ear (BTE) hearing devices as, for most people, the dimensions are too large to fit into the ear canal.

[0011] As reported by Knowles Corporation, the volume of the smallest dynamic speaker is still more than double the size of a typical balanced armature receiver.

[0012] Despite the many advantages of balanced armature receivers as compared with dynamic speakers, there are also some disadvantages. Balanced armatures are more sensitive to mechanical shock than dynamic speakers (moving coil receivers). With receivers being one of the more shock sensitive components in hearing aids, there is a desire to improve shock resistance. Also, the output of balanced armature receivers is inherently non-linear relative to the driving signal, whereas the output of moving coil receivers is inherently linear. A linear output relative to the driving signal (i.e. input) can be advantageous for example if the hearing aid includes advanced signal processing features such as Active Noise Cancelling (ANC). Further, due to lower distortion, the sound quality of moving coil receivers is generally better, resulting in a better user experience when listening to music. A moving coil receiver is also generally easier to manufacture and contains less components as compared with a balanced armature receiver.

[0013] US2021 / 0360350 describes a planar coil, secured to a diaphragm where the windings are arranged in the same plane, i.e. parallel to, the diaphragm. A plurality of permanent magnets are arranged in the rear volume below the planar coil. The volumetric efficiency of such a planar arrangement leaves much to be desired and is therefore not effective for use for receivers for in ear canal applications such as hearing aids.

[0014] US2008 / 044044 describes a dual moving coil speaker. According to the patent specification, dimensions may be smaller than 20 x 10 x 6 mm, such as a cylindrical housing in the range of 3-6 mm, with a height of 4-6 mm, making it generally unsuitable for use in the ear canal of a person. To reduce the size of the dual moving coil speaker, a first receiver housing portion of the dual moving coil speaker is magnetically conductive, which is generally not a biocompatible material. Further, there is still a need for further improvement in terms of efficiency and more closely matching the performance of balanced armature receivers.

[0015] DESCRIPTION OF THE INVENTION

[0016] It would be desirable to provide a receiver that combines the advantages of a balanced armature receiver with a moving coil receiver, that is a receiver that has limited power consumption; has dimensions that allow it to fit into the ear canal of a person, that preferably has a fit rate of more than 70% of adults; has a more linear output; lower distortion; a peak output typically in the range of from 2500 - 3000 Hz to compensate for an open ear canal natural resonance; that is easier to manufacture using less components; and is highly efficient, that is able to produce a high SPL at the small dimensions.

[0017] It may therefore be seen as an object of embodiments of the present invention to provide for a receiver that combines one or more, preferably all, of these advantages. The present invention provides such a receiver.

[0018] Accordingly, the present invention provides according to a first aspect, a receiver for use in an ear canal of a person in accordance with claim 1. Thus, according to a first aspect, the present invention provides a receiver for use in an ear canal of a person comprising a receiver housing having a sound outlet in acoustic communication with a first and a second front volume within the receiver housing; - a first hinged diaphragm arranged within the receiver housing and separating a first front volume and a first rear volume within the receiver housing, wherein the first hinged diaphragm comprises a hinged portion and a moveable portion, and wherein a first voice coil is secured to the moveable portion of the first hinged diaphragm, to form a first diaphragm voice coil assembly, which moveable portion of the first hinged diaphragm is adapted to vibrate in response to a drive signal applied to the first voice coil;

[0019] - a second hinged diaphragm arranged within the receiver housing and separating a second front volume and a second rear volume within the receiver housing, wherein the second hinged diaphragm comprises a hinged portion and a moveable portion, and wherein a second voice coil is secured to the moveable portion of the second hinged diaphragm, to form a second diaphragm voice coil assembly, which moveable portion of the second hinged diaphragm is adapted to vibrate in response to a drive signal applied to the second voice coil; wherein the first and second rear volumes comprise a magnetic motor configured to generate a static magnetic field in a space within which at least part of the first and second voice coils are positioned.

[0020] Preferably, a residual acoustic rear first volume in the first rear volume, and a residual acoustic rear second volume in the second rear volume, is at most 15 mm3; a combined acoustic mass of the first, respectively second, diaphragm and voice coil assembly is at most 130000 kg / m4; and the product of the combined acoustic mass of the first, respectively second, diaphragm and voice coil assembly times the residual acoustic rear first, respectively second, volume is in the range of from 3.0E-4 to 9.5E-4 kg / m.

[0021] More preferably, the first and second rear volumes are acoustically connected to form a shared rear volume. The shared rear volume may have dimensions such that the residual acoustic rear shared volume in the shared rear volume is similar to the residual acoustic rear volume in each of the first and second rear volumes. Thus, according to a preferred embodiment, the receiver for use in an ear canal of a person is configured such that a residual acoustic rear volume in the shared rear volume is at most 15 mm3; a combined acoustic mass of each (first and second) diaphragm and voice coil assembly is at most 130000 kg / m4; and the product of the combined acoustic mass of each diaphragm and voice coil assembly times the residual acoustic rear volume (expressed in m3) is in the range of from 3.0E-4 to 9.5E-4 kg / m. Typically, the combined acoustic mass of the first diaphragm and voice coil assembly is substantially the same as the combined acoustic mass of the second diaphragm and voice coil assembly. Preferably, the first diaphragm and voice coil assembly and the second diaphragm and voice coil assembly form a mirror symmetrical arrangement around a central plane extending parallelly to the first and second diaphragms. Preferably, the first and second voice coils are connected to the same drive signal but in opposite phase.

[0022] The residual acoustic rear volume is the volume of air in a rear volume, that is the rear volume between both diaphragms, excluding the volume of any solid components in that rear volume, such as voice coil and magnetic motor.

[0023] The acoustic mass is determined as follows:

[0024] • Measure the residual acoustic rear volume V_rear in m3;

[0025] • Measure the first main acoustic resonance f0of the receiver in Hz; and

[0026] • Calculate the total acoustic mass Ma_tot by solving the following equation:

[0027] In which rho_air = 1.225 kg / m3 and c_air = 340 m / s.

[0028] As the desired output of the receiver is acoustical, i.e. in the acoustical domain, and the construction of each diaphragm and voice coil assembly is in the mechanical domain, the mass of the first and second diaphragm and first and second voice coil (expressed in kg) may be converted to an equivalent acoustical mass. It belongs to the skill of those skilled in the art to convert (mechanical) mass of the diaphragm of a voice coil and diaphragm assembly into an equivalent acoustical mass. In essence, Matot = [m(diaphragm) + m(VOicecoii)] / A2, in which m is the mass of (first or second) diaphragm, respectively voice coil, and A is the area of the (first or second) diaphragm. In the configuration where a first or second hinged diaphragm is used, not all of the (first or second) diaphragm contributes equally to the movement of air and the effective contribution of each part of the (first or second) diaphragm is calculated by means of integration as follows:

[0029] In which Aeff is the effective area and the force point (FP) amplitude is the amplitude of the (first or second) diaphragm at the centre of the (first or second) voice coil; and

[0030] In which mdiaphragm effis the effective mass of the (first or second) diaphragm and FP is the force point, i.e. the centre of the (first or second) voice coil. The effective mass of the (first or second) voice coil, mvolce coil eff, may be determined in a similar way.

[0031] The residual acoustic air volume equivalent in the acoustic domain is the acoustic compliance. Acoustic compliance, Ca, may be determined using the following equation:

[0032] In which rho_air = 1.225 kg / m3; c_air = 340 m / s and V_rear is the residual acoustic rear volume in m3.

[0033] Preferably, in embodiments of the invention according to the first, second and third aspect, the acoustic compliance is at most 1.04E-13 m5 / N. Furthermore, preferably, in embodiments of the invention according to the first, second and third aspect, the product of the combined acoustic mass of the diaphragm and voice coil times the acoustic compliance is in the range of from 2.1E-9 to 6.3E-9 s2.

[0034] In embodiments of the invention where the first and second rear volumes are acoustically connected to form a shared rear volume, preferably, the product of the combined acoustic mass of each diaphragm and voice coil assembly times the acoustic compliance of the shared residual acoustic rear volume is in the range of from 2.1E-9 to 6.3E-9 s2.

[0035] Preferably, the residual acoustic rear volume in the first, second or shared rear volume is at most 14 mm3, more preferably at most 12 mm3, even more preferably at most 11 mm3. Preferably, the residual acoustic rear volume in the first, second or shared rear volume is at least 7 mm3, more preferably at least 8 mm3.

[0036] Preferably, the combined acoustic mass of each diaphragm and voice coil assembly is at most 90000 kg / m4, more preferably at most 60000 kg / m4. Preferably, the combined acoustic mass of each diaphragm and voice coil assembly is at least 25000 kg / m4, more preferably at least 30000 kg / m4.

[0037] Preferably, the product of the combined acoustic mass of each diaphragm and voice coil assembly times the residual acoustic rear volume (as applicable in the first, second or shared rear volume, expressed in m3) is in the range of from 3.9E-4 to 8.9E-4 kg / m, more preferably in the range of from 3.9E-4 to 6.4E-4 kg / m.

[0038] Preferably, at least the part of the receiver housing which is designed for direct contact with an ear canal, is at least partly made of a biocompatible material. The part of the receiver housing that may be in direct contact with an ear canal may (substantially) completely be covered by an outer layer of a biocompatible material or may be formed from a biocompatible material.

[0039] Biocompatible materials are known in the art and are for example described in United States patent specification No. 7,680,292, incorporated herein by reference. Examples include polyolefins such as polypropylene or polyamides, such as glass-reinforced polyamides.

[0040] Hearing aid devices using a receiver in canal are currently typically designed for balanced armature drivers. One consequence of this is that any amplifiers used in such hearing aid devices need to have a high impedance of at least 40 Ohm. It would be desirable to be able to use the receiver of the present invention in existing hearing aid designs, without having to change or re-design other components used in hearing aid devices, such as amplifiers.

[0041] Preferably, each voice coil comprises at least 24 windings, more preferably 60 to 120 windings, of insulated electrically conductive wire, where the diameter of the electrically conductive wire is at most 22 pm. More preferably, the diameter of the electrically conductive wire is in the range of from 12 to 18 pm. If the diameter of the electrically conductive wire is more than 22 pm, a high impedance is more difficult to achieve, and the combined required acoustic mass of voice coil and diaphragm becomes more difficult to achieve as well. If the diameter of the electrically conductive wire is less than 12 pm, handling of the electrically conductive wire becomes more difficult and the risk that the wire breaks during manufacture increases, resulting in loss of yield. Preferably each voice coil is configured such that the impedance is at least 16 Ohm, preferably at least 30 Ohm, more preferably at least 40 Ohm.

[0042] The receiver housing is typically elongated, such as oblong, and the first and / or second diaphragm is typically elongated, such as oblong, as well. Preferably, the first and / or second diaphragm comprises a hinged diaphragm arranged within the elongated, oblong, receiver housing. The hinged first and / or second diaphragm comprises a hinged portion and a moveable portion, wherein at least the moveable portion of the first and / or second diaphragm is configured to vibrate in response to the drive signal. In this embodiment, the first, respectively second, voice coil is secured to the moveable portion of the first, respectively second, diaphragm, preferably at a distance from the hinged portion. In the present context the term "hinged diaphragm" should be understood as a diaphragm that is hinged to for example a frame structure. The hinging of the first and / or second diaphragm to for example a frame structure may be arranged in various ways, such as by applying one or more integrated hinges, applying one or more distinct and separate hinges and / or one or more film-based hinges.

[0043] Preferably, the hinged first and / or second diaphragm is substantially rectangular and the first and / or second diaphragm is hinged on one side of the substantially rectangular diaphragm, more preferably a short end of the substantially rectangular diaphragm. Preferably the first, respectively second, voice coil is positioned such that at least part of the outer perimeter of the first, respectively second, voice coil is positioned substantially at the end opposite the end where the first, respectively second, diaphragm is hinged.

[0044] According to a preferred aspect of the receiver of the present invention, the receiver comprises an oblong receiver housing; one or more, such as two, sound output port(s) arranged in the oblong receiver housing; a first hinged diaphragm arranged within the oblong receiver housing and separating a first front volume from a first rear volume, or from a shared rear volume, within the oblong receiver housing, wherein the first hinged diaphragm comprises a hinged portion and a moveable portion, and wherein at least the moveable portion of the first hinged diaphragm is adapted to vibrate in response to a drive signal applied to a first voice coil secured to the moveable portion of the first diaphragm; a second hinged diaphragm arranged within the oblong receiver housing and separating a second front volume from a second rear volume, or from a shared rear volume, within the oblong receiver housing, wherein the second hinged diaphragm comprises a hinged portion and a moveable portion, and wherein at least the moveable portion of the second hinged diaphragm is adapted to vibrate in response to a drive signal applied to a second voice coil secured to the moveable portion of the second diaphragm; and a magnetic motor arranged within the oblong receiver housing, wherein the magnetic motor is adapted to generate a static magnetic field in an air gap within which at least part of first and voice coil is positioned.

[0045] Hinging of the first and / or second hinged diaphragm is advantageous in that the hinge avoids or at least counteracts rocking modes, i.e. undesired tilting motions of the diaphragm in question. This is a widely known phenomenon in conventional (non-hinged) moving coil loudspeaker designs. In conventional designs of miniature receivers, the small diaphragm sizes are, in general, associated with relatively large driving amplitudes, which in combination frequently triggers problems with rocking modes. Since the amplitude of the tilting motion scales with voice coil excursion, and since the air gaps for the voice coil are narrow for efficiency reasons (typically in the range of from 0.15 to 0.35 mm), the voice coil will at a certain level hit the magnet causing excessive impulsive distortion due to rubbing. The rubbing of the voice coil along the air gap (magnet) wall also quickly breaks the coatings of the voice coil wire and can thus cause the receiver to fail. Thus, the risk of rocking modes imposes strong limitations of usable output and lifetime of conventional miniature receivers, let alone receivers for use in an ear canal of a person as in the present invention.

[0046] According to a preferred embodiment, the first and / or second hinged diaphragm is hinged to a first and / or second frame structure, and wherein one or more openings exist between the first and / or second hinged diaphragm and the first and / or second frame structure.

[0047] The hinged portion of the first and / or second hinged diaphragm is preferably hinged to a first and / or second frame structure via one or more discrete and separate hinges and / or via one or more integrated hinges.

[0048] In the present context the term "integrated hinges" is to be understood as hinges that are integrated with the first and / or second frame structure, the first and / or second hinged diaphragm or both. The first and / or second hinged diaphragm and the first and / or second frame structure may form an integrated structure of the same material, such as metal, preferably aluminum.

[0049] The one or more openings between the first and / or second hinged diaphragm and the first and / or second frame structure are provided so that at least part of the first and / or second hinged diaphragm is allowed to vibrate, and thus generate audible sound waves, when a drive signal is applied to the first and / or second voice coil. The one or more openings between the first and / or second hinged diaphragm and the first and / or second frame structure may at least partly be sealed or filled with a flexible sealing member, such as a (corrugated) polymer film or a viscoelastic substance such as a viscoelastic gel. Sealing the one or more openings is advantageous in order to acoustically separate the front and rear volumes of the receiver.

[0050] At least part of the first and / or second hinged diaphragm may comprise an embossed part for increasing the stiffness of the first and / or second hinged diaphragm. The embossed part may be implemented as an indentation or recess that extends in the opposite direction of the first and / or second voice coil secured to the moveable portion of the first and / or second hinged diaphragm. Another way of increasing the stiffness of the first and / or second hinged diaphragm may be to secure a stacked layer or stacked pre-formed layer to the first and / or second hinged diaphragm. The embossed part of at least part of the first and / or second hinged diaphragm may provide an air venting path for air inside the magnetic motor as discussed in relation to some of the drawings.

[0051] Preferably, the first and / or second hinged diaphragm has an elongated, oblong, preferably substantially rectangular, shape, wherein the length of the first and / or second hinged diaphragm in the elongated, oblong direction is at least twice the width of the first and / or second hinged diaphragm. Thus, the length of the first and / or second hinged diaphragm in the elongated, oblong direction may be three times, four times, five times or even ten times the width of the first and / or second hinged diaphragm. The elongated, oblong shape of the first and / or second hinged diaphragm is advantageous in that it maximises the area of the first and / or second hinged diaphragm within the elongated, oblong receiver housing. Moreover, the maximised area of the first and / or second hinged diaphragm enhances the performance of the receiver. According to a particularly preferred embodiment, the dimensions of the first and second hinged diaphragms are substantially the same.

[0052] The first and / or second voice coil typically may be in the form of a cylinder or a cuboid with the top side and bottom side of the cylinder or cuboid being open. The top side of the first and / or second voice coil is the part of the first and / or second voice coil nearest to the moveable portion of the first and / or second hinged diaphragm. The bottom side of the first and / or second voice coil is the part opposite the top side and furthest from the moveable portion of the first and / or second hinged diaphragm. The top-side (and bottom side) view of the cylindrical first and / or second voice coil may be a plane that is an ellipse shape or a circle. The top-side (and bottom side) view of the cuboid first and / or second voice coil may be a plane that is a substantially square or rectangular shape. If desired, the edges of the substantially square or rectangular shape may be rounded. In this specification, the cuboid shaped voice coil is referred to as a substantially square (also referred to in this specification as quadratric) or rectangular voice coil. The cylinder-shaped voice coil may be referred to as an ellipsoid (oval-shaped) or circle-shaped voice coil. Preferably, the first and / or second voice coil is rectangular. According to a particularly preferred embodiment, the dimensions of the first and second voice coils are substantially the same.

[0053] The first, respectively second, voice coil is typically secured to the first, respectively second, hinged diaphragm, in particular to the movable portion of the first, respectively second, hinged diaphragm comprising a hinged portion and a moveable portion. The first, respectively second, voice coil preferably comprises at least 24 windings of insulated electrically conductive wire, preferably 60 to 120 windings of insulated electrically conductive wire, where the diameter of the electrically conductive wire is at most 22 pm. Preferably, the diameter of the electrically conductive wire is in the range of from 12 to 18 pm. The relevant diameter is the diameter of the electrically conductive wire itself, without insulating layer. In principle, any electrically conductive wire, such as copper, may be used. Preferably, an electrically conductive wire is used with a ratio of conductivity to mass density higher than copper. Preferably, the mass density of the electrically conductive wire is less than 3 g / cm3. More preferably, the electrically conductive wire is essentially aluminum. If desired, the aluminum wire may be coated with copper or silver, for example to improve solderability.

[0054] The first, respectively second, voice coil extends in a direction essentially perpendicular to the first, respectively second, hinged diaphragm. Thus, windings of the first, respectively second, voice coil extend essentially perpendicular to the first, respectively second, hinged diaphragm and the thickness of a side of the first, respectively second, voice coil secured to the first, respectively second, hinged diaphragm is therefore essentially the diameter of one electrically conductive wire, plus any insulating material. The first, respectively second, voice coil is at least in part positioned in an air gap of the magnetic motor. The first, respectively second, hinged diaphragm to which the first, respectively second, voice coil is preferably secured, reduces rocking modes. This, in turn allows to dimension the width of the air gap in which the first, respectively second, voice coil is positioned, to be in the range of from 0.15 to 0.35 mm, which is primarily advantageous to increase magnetic flux density in the air gap, increasing the magnetic motor force. A small air gap is also advantageous for reducing the residual acoustic rear volume in the first, second or shared rear volume to at most 15 mm3.

[0055] The length of the first, respectively second, hinged diaphragm in the oblong direction is at least twice the diameter or the width of the first, respectively second, voice coil secured to the moveable portion of the first, respectively second, hinged diaphragm. Thus, the length of the first, respectively second, hinged diaphragm in the oblong direction may be three times, four times, five times or even ten times the diameter or the width of the first, respectively second, voice coil. The width of the first, respectively second, voice coil may correspond to the side length of a square voice coil or the shortest side length of a rectangular voice coil. The diameter of the first, respectively second, voice coil may correspond to the shortest diameter of the ellipsoid (oval shaped) voice coil or the diameter of the circle-shaped voice coil.

[0056] An air venting opening may be arranged in the oblong receiver housing. The air venting opening may be displaced or shifted relative to the magnetic motor. The air venting opening may be oppositely arranged relative to the first and / or second sound outlet port, or it may be arranged as side opening in the oblong receiver housing. In any case, the air venting opening may be adapted to vent the first and / or second or shared rear volume of the receiver. Preferably, the receiver of the invention comprises an air venting opening in a wall encompassing the first and / or second rear volume, or in a wall encompassing a shared rear volume, which is configured to vent the first and / or second rear volume, or shared rear volume, to an enclosed vent volume.

[0057] The air venting opening may comprise an acoustical filter element forming an acoustical filter having an acoustical resistance, such as an acoustical low-pass filter having an acoustical resistance in the range of 1 - 20 GPa.s / m3.

[0058] The cut-off frequency of such an acoustical low-pass filter may be in range of 100-1000 Hz, such as 200-800 Hz, and the acoustical low-pass filter may be implemented as a mesh comprising one or more small holes (drilled or laser-cut), wire mesh, grid, fabric, non-woven fabric or another arrangement with similar acoustical properties. The purpose of the acoustical filter is to allow the first, respectively second, or shared rear volume of the receiver to be vented for signal frequencies below the filter cut-off, and to inhibit venting for frequencies above the cut-off. The advantage of such a filter is that the low frequency output is increased, while the main resonance frequency is not affected by the additional volume. The main property of the acoustical filter is the acoustical resistance. The acoustical resistance of the acoustical filter that is required to achieve a certain cut-off frequency is dependent of the acoustical compliance of the first, respectively second, or shared rear volume. For example, in order to have a cut-off frequency of 500 Hz with a first, respectively second, or shared rear volume between 10 and 15 mm3, the acoustical resistance of the acoustical filter may be between 1.3 and 10 GPa.s / m3.

[0059] The magnetic motor is preferably a shared motor. The magnetic motor may thus comprise a stacked arrangement of a permanent magnet, a first inner yoke and a second inner yoke, wherein the permanent magnet, the first and second inner yokes are at least partly arranged within an outer yoke so that a first air gap is provided between the first inner yoke and the outer yoke and a second air gap is provided between the second inner yoke and the outer yoke. The first, respectively second, air gap is adapted to receive at least part of the first, respectively second, voice coil, i.e. the first, respectively second, voice coil is at least partly arranged within the first, respectively second, air gap.

[0060] The outer yoke may comprise one or more ventilation openings adapted to ventilate an air volume inside the magnetic motor. Proper ventilation of the magnetic motor is advantageous as it may lead to an increased performance of the receiver. Suitably, the outer yoke is essentially cylindrical or cuboid shaped, with an open top and bottom end, in cross-section along the same plane as the first and second hinged diaphragm, of substantially the same shape as the first and second voice coil, but with a larger diameter to accommodate the first and second voice coil in the air gap between the outer yoke and the permanent magnet, first and second inner yoke assembly.

[0061] The magnetic motor, in particular the outer yoke, may according to one embodiment form part of the receiver housing. If it is desired that the receiver housing is formed at least in part of biocompatible material, the outer yoke, and any other metallic parts of the receiver housing, may be overmolded with a biocompatible material.

[0062] The first, respectively second, voice coil is preferably elongated, such as rectangular or oval shaped where the longest elongation such as the longest side length of a rectangular first, respectively second, voice coil or the longest diameter of an oval shaped first, respectively second, voice coil is arranged substantially parallel to the length of the first, respectively second, hinged diaphragm in the oblong direction. In this embodiment, the length of the first, respectively second, hinged diaphragm in the oblong direction is at least 1.1 times, preferably at least 1.3 times, 1.5 times or 1.7 times, such as 2.0 times the longest elongation, such as the longest diameter or the longest side length, of the first, respectively second, voice coil secured to the moveable portion of the first, respectively second, hinged diaphragm. The length of the first, respectively second, hinged diaphragm in the oblong direction may be up to 4 times, such as up to 3 times, 2.5 times, or 2 times the longest elongation, such as the longest diameter or the longest side length, of the first, respectively second, voice coil.

[0063] The elongated, oblong, receiver housing may typically have an outer width in the range of 3- 5.5 mm, an outer height within the range of 1.5-5 mm, and an outer length, excluding nozzle and cable strain relief, in the range of 6-9 mm. Preferably, the receiver housing is shaped such that the fit rate for adults of the receiver for use in the ear canal is at least 90%. A fit rate may be improved by a receiver housing that is made of a biocompatible material, and a separate biocompatible cover for the receiver housing can be avoided; and by shaping the receiver housing such that the fit rate in the outer ear canal is improved. Thus, according to one embodiment, the receiver housing, when viewed in longitudinal cross-section through essentially the entire receiver housing, may have a curved or bended shape.

[0064] Preferably, the receiver is configured to a resonance frequency peak, first main acoustic resonance peak of the receiver (f0), in the range of from 2.0 to 3.5 kHz, more preferably of from 2.5 to 3 kHz.

[0065] According to another aspect, the present invention relates to a first, respectively second, voice coil for use in a receiver as described herein, wherein the first, respectively second, voice coil comprises at least 24 windings of insulated electrically conductive wire, preferably 60 to 120 windings of insulated electrically conductive wire, where the diameter of the electrically conductive wire is at most 22 pm. Preferably, the diameter of the electrically conductive wire is in the range of from 12 to 18 pm. Other preferred embodiments of the first, respectively second, voice coil have been described hereinabove.

[0066] Preferably, the first, respectively second, voice coil is made of self-bonding coil wire, that is film isolated wire which is coated with an additional bonding adhesive.

[0067] According to another aspect, the present invention relates to a receiver-in-canal assembly comprising a receiver as described herein; a connector; and an electrically conductive wire for connecting the receiver with the connector, which connector is configured to connect with a second connector in a hearing device housing external to the ear canal. According to one embodiment, the receiver in canal assembly further comprises a microphone, in particular a MEMS microphone, in the receiver housing or downstream from the receiver housing. The MEMS microphone may suitably be positioned in the first, second or shared rear volume of the receiver housing, downstream from the magnetic motor.

[0068] According to another aspect, the present invention relates to a receiver I microphone assembly comprising a receiver as described herein, wherein the receiver housing further comprises a microphone, in particular a MEMS microphone. Suitably, the MEMS microphone may be positioned in the first, second or shared rear volume of the receiver housing, downstream from the magnetic motor.

[0069] According to another aspect, the present invention relates to a hearing aid device comprising a receiver in canal assembly as described herein and a hearing device housing comprising a second connector configured for connecting with the connector of the receiver in canal assembly; a power source such as a battery; one or more microphones configured to receive sound from sources external to the ear canal of a person and generate first output signal(s); and a processor configured to provide the drive signal for the first and second voice coil in the receiver in canal assembly from the first output signal(s). According to one embodiment, in determining the drive signal, the processor may be configured to operate an Active Noise Cancelling algorithm.

[0070] Preferably, the processor is further configured to receive a second output signal from the microphone in the receiver in canal assembly, and provide the drive signal for the first and second voice coil in the receiver in canal assembly from the first output signal(s) and the second output signal. According to one embodiment, in determining the drive signal, the processor may be configured to operate an Active Noise Cancelling (ANC) algorithm and / or an Active Occlusion Reduction (AOR) algorithm. An AOR algorithm and system may be similar to an ANC algorithm and system but in case of AOR the noise targeted for cancellation comprises occlusion related noise sources.

[0071] In general, the various aspects of the present invention may be combined and coupled in any way possible within the scope of the invention. These and other aspects, features and / or advantages of the present invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0072] BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In the following, example embodiments will be described with reference to the drawings, wherein:

[0074] Figure 1 illustrates a receiver according to the invention in longitudinal cross-section.

[0075] Figure 2 illustrates a top view of a hinged diaphragm of a receiver according to the present invention.

[0076] Figure 3 illustrates top views of other hinged diaphragms, where Fig. 3a shows a film-based hinge, and Fig. 3b shows two distinct and separate glue hinges.

[0077] DETAILED DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 illustrates a receiver according to the invention in longitudinal cross-section. The receiver 100 comprises a receiver housing formed by first volume cover 101, second front volume cover 102 and outer yoke 111. In another embodiment, the outer yoke 111 does not form part of the receiver housing, but is positioned fully in the receiver housing and a separate cover (not shown in Figure 1) is provided to cover the outer yoke 111. First volume cover 101 comprises a first sound outlet 104 in acoustic communication with a first front volume 110 and second volume cover 102 comprises a second sound outlet 105 in acoustic communication with a second front volume 120. If desired, sound outlets 104 and 105, are both in acoustic communication with a nozzle (not shown). Suitably a flexible dome (not shown) may be attached to the nozzle for positioning in the ear canal of a person and the combined sound output from the first and second sound outlets 104, 105 is fed via the nozzle and flexible dome into the ear canal of a person.

[0079] The receiver housing 101, 111, 102 is configured to receive a first frame structure 118 and first diaphragm 116 containing an embossed part 117. First diaphragm 116 is hinged in the first frame structure 118 via hinges 115. The hinged first diaphragm 116 comprises a hinged portion and a moveable portion, wherein at least the moveable portion of the hinged first diaphragm 116 is adapted to vibrate, and thus generate sound waves, in response to a drive signal applied to a first voice coil 136 secured to the moveable portion of the hinged first diaphragm 116.The receiver housing is further configured to receive a second frame structure 128 and second diaphragm 126 containing an embossed part 127. Second diaphragm 126 is hinged in the second frame structure 128 via hinges 125. The hinged second diaphragm 126 comprises a hinged portion and a moveable portion, wherein at least the moveable portion of the hinged second diaphragm 126 is adapted to vibrate, and thus generate sound waves, in response to a drive signal applied to a second voice coil 137 secured to the moveable portion of the hinged second diaphragm 126. The embossed parts 117, 127 may increase the stiffness of the diaphragms 116, 126. In addition, or alternatively, they may provide air venting paths so that the air volume inside the magnetic motor (111, 130, 140, 135) can be vented. First seal 191 functions to seal the first front volume 110 from the first rear volume 150. Similarly, second seal 192 functions to seal the second front volume 120 from the second rear volume 150'. Seal 191 and 192 may be a flexible and / or stretchable foil, for instance a polyurethane foil or a corrugated polymer film. Suitably, the seal 191 functions to seal gaps between first frame structure 118 and first diaphragm 116 and seal 192 functions to seal gaps between second frame structure 128 and second diaphragm 126. In another embodiment, the gaps between diaphragms and frame structures may be sealed with a viscoelastic substance such as a viscoelastic gel.

[0080] The first voice coil 136 is positioned in an air gap between outer yoke 111, inner yoke 130 and permanent magnet 135. Second voice coil 137 is positioned in an air gap between outer yoke 111, inner yoke 140 and permanent magnet 135. In the embodiment depicted in figure 1 one permanent magnet 135 is shown but, alternatively, the permanent magnet 135 may be a plurality of stacked permanent magnets. According to one embodiment, first voice coil 136 is positioned in an air gap between outer yoke 111, inner yoke 130 and a first permanent magnet and second voice coil 137 is positioned in an air gap between outer yoke 111, inner yoke 140 and a second permanent magnet. Preferably, the first and second voice coils share a common magnetic circuit. Thus, a shared magnetic motor is configured to generate a static magnetic field in a space within which at least part of the first and second voice coils are positioned. In the air gap between outer yoke 111, inner yoke 130 and permanent magnet 135, and in the air gap between outer yoke 111, inner yoke 140 and permanent magnet 135, a permanent magnetic flux is formed. The voice coils 136, 137, are positioned in their respective air gaps and, in operation, a drive signal applied to the first voice coil 136, respectively the second voice coil 137, causes the first diaphragm 116, respectively second diaphragm 126, to vibrate. Preferably, the drive signal applied to both voice coils is the same, a shared permanent magnet 135 is used, and diaphragms 116, 126 vibrate substantially the same, such that sound leaving sound output 104 is substantially the same as sound leaving sound output 105. First voice coil 136 and second voice coil 137 may be connected to the drive signal in opposite phase. Permanent magnet positioner 180 is configured to secure the permanent magnet 135 to the outer yoke 111. Typically, permanent magnet positioner 180 is made of the same material as outer yoke 111, such as mu-metal. In one embodiment, permanent magnet positioner 180 is configured to acoustically separate the first rear volume 150 from the second rear volume 150'. According to a preferred embodiment, the first and second rear volumes 150, 150' are acoustically connected to form a shared rear volume. It will be appreciated that in that preferred embodiment, permanent magnet positioner 180 is not configured to acoustically separate the first rear volume 150 from the second rear volume 150'.

[0081] Preferably, as shown in figure 1, the space indicated with 160 is configured as a closed venting volume with venting openings 170 for first and second rear volume 150, 150'. Preferably the closed venting volume is as large as possible, for example 10-15 mm3. Venting openings 170, typically 0.6-0.9 mm in diameter, are provided in acoustic communication with the residual acoustic, first and second, rear volume. The venting openings 170 each comprise an acoustical filter (not shown), such as a low-pass filter, having an acoustical resistance in the range of 1 - 20 GPa.s / m3. The acoustical filters may be implemented in various ways, such as an acoustical mesh. The venting volume 160 provides additional efficiency, especially at low frequencies such as below 800 Hz. The closed nature of the venting volume 160 ensures that undesirable feedback in the ear canal is reduced or even eliminated.

[0082] Alternatively, the space in figure 1 indicated by 160 may be filled with solid material, for example plastic. In this way, the residual acoustic rear volume in the first and second rear volume is kept within preferred limits, such as at most 15 mm3.

[0083] Turning now to Figure 2, a top view of an integrated assembly 200 comprising the hinged diaphragm 201 and the frame structure 202 is depicted. The hinged diaphragm 201 and the frame structure 202 preferably form an integrated structure of the same material, such as metal including aluminum. The hinged diaphragm 201 is hinged to the frame structure 202 via hinges 205, 205' that are integrated hinges. The openings 204, 206 between the hinged diaphragm 201 and the frame structure 202 are sealed with a corrugated polymer film having one or more venting opening 207 arranged between the hinges 205, 205'. Alternatively, or in addition one or more venting openings (not shown) may be provided in opening 204. The one or more venting openings are provided to equalize the barometric pressure between the front and the rear volume. At least part of the hinged diaphragm 201 comprises an embossed part 203 for increasing the stiffness of the diaphragm and / or for providing an air venting path as will be discussed in further detail below.

[0084] In an alternative arrangement, the hinged diaphragm 301, 306 is hinged to the frame structure 302, 307 via discrete and separate glue hinges 304, 310, 310', cf. Figs. 3a-b. With reference to Fig. 3a, a thin film 305 in the narrow gap between the hinged diaphragm 301 and the frame structure 302 acts as a hinge 304. The opening 303 between the hinged diaphragm 301 and the frame structure 302 is sealed with a corrugated polymer film. In Fig. 3b discrete and separate hinges 310, 310' are secured to the hinged diaphragm 306 and the frame structure 307. The opening 308 between the hinged diaphragm 306 and the frame structure 307 is sealed with a corrugated polymer film, and the opening 309 between the hinges 310, 310' is sealed with a film that may comprise venting / barometric openings (not shown).

[0085] Although the present invention has been discussed in the foregoing with reference to exemplary embodiments of the invention, the invention is not restricted to these particular embodiments which can be varied in many ways without departing from the invention. The discussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary, the embodiments are merely intended to explain the wording of the appended claims, without intent to limit the claims to these exemplary embodiments. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exemplary embodiments.

Claims

CLAIMS1. A receiver for use in an ear canal of a person comprising a receiver housing having a sound outlet in acoustic communication with a first and a second front volume within the receiver housing; a first hinged diaphragm arranged within the receiver housing and separating a first front volume and a first rear volume within the receiver housing, wherein the first hinged diaphragm comprises a hinged portion and a moveable portion, and wherein a first voice coil is secured to the moveable portion of the first hinged diaphragm, to form a first diaphragm voice coil assembly, which moveable portion of the first hinged diaphragm is adapted to vibrate in response to a drive signal applied to the first voice coil; a second hinged diaphragm arranged within the receiver housing and separating a second front volume and a second rear volume within the receiver housing, wherein the second hinged diaphragm comprises a hinged portion and a moveable portion, and wherein a second voice coil is secured to the moveable portion of the second hinged diaphragm, to form a second diaphragm voice coil assembly, which moveable portion of the second hinged diaphragm is adapted to vibrate in response to a drive signal applied to the second voice coil; wherein the first and second rear volumes comprise a magnetic motor configured to generate a static magnetic field in a space within which at least part of the first and second voice coils are positioned.

2. A receiver according to claim 1, wherein the first and second rear volumes are acoustically connected to form a shared rear volume.

3. A receiver according to claim 2, wherein a residual acoustic rear volume in the shared rear volume is at most 15 mm3; a combined acoustic mass of each (first and second) diaphragm and voice coil assembly is at most 130000 kg / m4; and the product of the combined acoustic mass of each diaphragm and voice coil assembly times the shared residual acoustic rear volume is in the range of from 3.0E-4 to 9.5E-4 kg / m.

4. A receiver according to claim 3, wherein the combined acoustic mass of the first diaphragm and voice coil assembly is substantially the same as the combined acoustic mass of the second diaphragm and voice coil assembly.

5. A receiver according to any one of the preceding claims, wherein the first diaphragm and voice coil assembly and the second diaphragm and voice coil assembly form a mirror symmetrical arrangement around a central plane extending parallelly to the first and second diaphragms.

6. A receiver according to any one of the preceding claims, wherein at least the part of the receiver housing that is designed for direct contact with an ear canal, is at least partly made of a biocompatible material.

7. A receiver according to any one of the preceding claims, further comprising an air venting opening in a wall encompassing the first and / or second rear volume, or shared rear volume, configured to vent the first and / or second rear volume, or shared rear volume, to an enclosed vent volume.

8. A receiver according to claim 7, wherein the air venting opening comprises an acoustical filter element, preferably having an acoustical resistance in the range of 1 - 20 GPa.s / m3.

9. A receiver according to any one of the preceding claims, wherein each voice coil comprises at least 24 windings of insulated electrically conductive wire, and wherein the diameter of the electrically conductive wire is at most 22 pm, preferably in the range of from 12 to 18 pm.

10. A receiver according to any one of the preceding claims, wherein the hinged portion of the first and / or second hinged diaphragm is hinged to a first and / or second frame structure via one or more discrete and separate hinges and / or via one or more integrated hinges.

11. A receiver according to any one of the preceding claims, wherein the receiver is configured to have a resonance frequency peak in the range of from 2.5 to 3 kHz.

12. A receiver according to any one of the preceding claims, wherein the magnetic motor comprises a shared permanent magnet and shared outer yoke.

13. A receiver according to any one of the preceding claims, wherein the magnetic motor comprises (i) a stacked arrangement of a permanent magnet and a first and second inner yoke and (ii) an outer yoke, wherein the permanent magnet and the first and second inner yoke are at least partly arranged within the outer yoke so that an air gap is provided between the stacked arrangement of the permanent magnet and first and second inner yoke and the outer yoke within which air gap the first and second voice coils are at least partly arranged.

14. A receiver in canal assembly comprising a receiver according to any one of the preceding claims; a connector; and an electrically conductive wire for connecting the receiver with the connector, which connector is configured to connect with a second connector in a hearing device housing external to the ear canal.

15. A hearing aid device comprising a receiver in canal assembly as claimed in claim 14 and a hearing device housing comprising a second connector configured for connecting with the connector of the receiver in canal assembly; a power source such as a battery; one or more microphones configured to receive sound from sources external to the ear canal of a person and generate first output signal(s); and a processor configured to provide the drive signal for the voice coil in the receiver in canal assembly from the first output signal(s).

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