Abstract:
The present invention relates to a receiver assembly comprising a first receiver having a distinct longitudinal direction and a first longitudinal centre line, and a second receiver having a distinct longitudinal direction and a second longitudinal centre line, wherein the distinct longitudinal directions of the first and second receivers are arranged essentially along a distinct longitudinal direction of the receiver assembly. The receiver assembly further comprises one or more microphone units.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of European Patent Application Serial No. 15201509.5, filed Dec. 21, 2015, which is incorporated herein by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a receiver assembly for hearing devices. In particular the present invention relates to a receiver assembly having a distinct longitudinal direction and a reduced thickness and/or width in order to fit into the ear canal of a human being. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various receiver assemblies for hearing devices, such as hearing aids, have been suggested over the years. 
         [0004]    As an example US 2012/0255805 A1 discloses a receiver assembly comprising two spatially shifted receivers in the form of a first U-shaped armature and a second U-shaped armature. The two receivers are spatially shifting in a longitudinal direction of the receiver assembly with the purpose of suppressing vibrations. However, as the two receivers of the assembly suggested in the US 2012/0255805 A1 are not arranged in-line, i.e. in continuation of each other, the overall height of the assembly might be problematic in relation to a receiver-in-canal (MC) hearing aid. Thus, there seems to be a need for hearing aid receiver assemblies, in particular MC assemblies, with a reduced height so as to fit into the human ear canal. 
         [0005]    It may be seen as an object of embodiments of the present invention to provide a receiver assembly having a distinct longitudinal direction. 
         [0006]    It may be seen as a further object of embodiments of the present invention to provide a receiver assembly that, to a large degree, follows the shape of an ear canal of a human being. 
         [0007]    It may be seen as a still further object of embodiments of the present invention to provide a receiver assembly being suitable for hearing devices. 
       SUMMARY OF INVENTION 
       [0008]    The above-mentioned objects are complied with by providing, in a first aspect, a receiver assembly comprising 
         [0009]    a first receiver having a distinct longitudinal direction and a first longitudinal centre line, 
         [0010]    a second receiver having a distinct longitudinal direction and a second longitudinal centre line, and 
         [0011]    one or more microphone units for receiving incoming sound, 
         [0012]    wherein the distinct longitudinal directions of the first and second receivers are arranged essentially along a distinct longitudinal direction of the receiver assembly, and wherein the first receiver, the second receiver and the one or more microphone units are at least partly arranged within an assembly housing. 
         [0013]    It is advantageous that the receiver assembly of the present invention has a distinct longitudinal direction, and thereby a distinct longitudinal shape, so that it fits into a typical ear canal of the human being. By distinct longitudinal shape is meant that the receiver assembly is significantly longer compared to its height and width. 
         [0014]    The distinct longitudinal shape of the receiver assembly may be provided in various ways. For example, the first and second receivers may be arranged with essentially parallel first and second longitudinal centre lines. Longitudinal centre lines are here to be considered as virtual lines extending in the respective distinct longitudinal directions of each of the first and second receivers. 
         [0015]    In one embodiment the first and second receivers may be spatially shifted in a direction being essentially perpendicular to first and second longitudinal centre lines. Thus, the first and second receivers may be spatially shifted in the height and/or width direction of the receivers. The spatial shifting of the receivers may amount up to around 50% of the height and/or width of the smallest receiver, in case the sizes of the two receivers are different. 
         [0016]    In another embodiment the first and second receivers may be arranged in an in-line configuration with essentially coinciding first and second longitudinal centre lines. In this embodiment the two receivers are arrangement in connection of each other. 
         [0017]    Each of the first and second receivers has a primary moving direction which may be defined as the direction of movement of a membrane. When incorporated into the receiver assembly of the present invention the first and second receivers may be arranged with their respective moving directions in essentially opposite directions in order to reduce vibrations. Alternatively, the first and second receivers may be arranged with their respective moving directions in essentially parallel directions. 
         [0018]    In yet another embodiment the first and second receivers may be arranged with angled first and second longitudinal centre lines. Thus, in this embodiment the first and second receivers are arranged relative to each other. This may be advantageous in that the receiver assembly may then follow a human ear canal even more effective. According to this embodiment the first and second receivers may be arranged with an angle of 5-45 degrees, such as 5-40 degrees, such as 5-35 degrees, such as 5-30 degrees, such as 5-25 degrees, such as 5-20 degrees, such as 5-15 degrees, such as 5-10 degrees, between the first and second longitudinal centre lines. 
         [0019]    The first and second receivers may be connected in various ways. One approach may be to connect the first and second receivers via an essential rigid connection, i.e. a mechanical hard connection. In this approach the receivers may be bolted directly together. In another approach the first and second receivers may be connected via a flexible connection, such as via a suspension member. The suspension member may prevent that vibrations being generated by one receiver reaches the other receiver, i.e. the suspension member may be applied as a vibration damping arrangement. 
         [0020]    The first and second receivers may be essentially identical receivers. Thus, both the first and second receivers may comprise moving armature receivers, such as balanced armature receivers. However, the frequency responses of the two receivers may be different, for example by including a tweeter receiver and a woofer receiver in the receiver assembly. It should be noted that the first and second receivers may differ in other ways, such as size, shape, functionality, vibration properties and/or applied motor type. 
         [0021]    The one or more microphone units of the receiver assembly may comprise MEMS microphones and/or electret microphones. 
         [0022]    The receiver assembly may further comprise one or more vibration isolating spacers being arranged between the assembly housing and the first and second receivers. The one or more vibration isolating spacers may form a free-space region between the assembly housing and the first and second receivers. The one or more microphone units may advantageous be, at least partly, arranged in the free-space region between the assembly housing and the first and second receivers. 
         [0023]    In a second aspect the present invention relates to an acoustical assembly comprising 
         [0024]    an assembly housing, 
         [0025]    a receiver module, and 
         [0026]    one or more spacers being arranged between the assembly housing and the receiver module, the one or more spacers forming a free-space region between the assembly housing and the receiver module. 
         [0027]    Thus, the second aspect of the present invention relates to an acoustical assembly where the receiver module is arranged in a box-in-a-box configuration with an assembly housing. The receiver module may comprise a single receiver, i.e. one receiver. Alternatively, the receiver module may comprise a receiver assembly according to the first aspect. 
         [0028]    The one or more microphone units may be at least partly positioned in the free-space region between the assembly housing and the receiver module. It is a space saving, and thereby advantageous feature, that the one or more microphones units may be positioned in the free-space region being provided by the one or more spacers. 
         [0029]    The one or more spacers may comprise one or more vibration isolating elements in order to vibration isolate the assembly housing from the receiver module. As previously addressed the one or more microphone units may comprise MEMS microphones and/or electret microphones. 
         [0030]    In a third aspect the present invention relates to a hearing device comprising an acoustical assembly according to the second aspect, said hearing device comprising a hearing aid being selected from the group consisting of: behind-the-ear, in-the-ear, in-the-canal and completely-in-the-canal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    The present invention will now be described in further details with reference to the accompanying figures, wherein 
           [0032]      FIG. 1  shows rigidly connected receivers in an in-line configuration and a shifted configuration, 
           [0033]      FIG. 2  shows flexible connected receivers in an in-line configuration and a shifted configuration, 
           [0034]      FIG. 3  shows angled receiver configurations, 
           [0035]      FIG. 4  shows a box-in-a-box configuration, 
           [0036]      FIG. 5  shows a box-in-a-box configuration with microphone units, 
           [0037]      FIG. 6  shows a box-in-a-box configuration with a single microphone unit and two microphones units with open back volumes, 
           [0038]      FIG. 7  shows a box-in-a-box configuration with a single microphone unit and two microphones units with closed and separated back volumes, and 
           [0039]      FIG. 8  shows a box-in-a-box configuration with two microphones units with a shared back volume. 
       
    
    
       [0040]    While the invention is susceptible to various modifications and alternative forms specific embodiments have been shown by way of examples in the drawings and will be described in details herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    In its most general aspect the present invention relates to a receiver assembly that via its elongated shape fits into a human ear canal. The receiver assembly of the present invention is therefore suitable for forming part of a hearing device, such as a hearing aid. 
         [0042]    Generally, the receiver assembly of the present invention comprises a plurality of receivers which may be either identical receivers or different receivers. For example, different receivers may be applied in a woofer/tweeter receiver configuration. The type and thereby functioning of the receivers may be different as well. Thus, armature receivers, moving coil receivers and electrostatic receivers may be combined to comply with certain demands. 
         [0043]    On order to fit within the human ear canal, i.e. follow the internal shape of the human ear canal, the plurality of receivers are arranged in an in-line, or nearly in-line, configuration. By in-line is meant that the plurality of receivers are arranged in continuation of each other. It should be noted however, that the plurality of receivers may be slightly angled and spatially shifted relative to each other. With the configuration of the present invention the receiver assembly will take an essential elongated shape although the receivers may be slightly angled and/or spatially shifted relative to each other. 
         [0044]    The plurality of receivers may be mutually connected by various means. Thus, the receivers may be mutually connected via a mechanically rigid connection, a flexible connection or a combination thereof. A flexible connection typically involves a membrane structure. 
         [0045]    A receiver assembly can be provided as a box-in-box configuration where the receiver assembly is arranged inside an outer housing. Vibration suspensions may be provided between the receiver assembly and the outer housing in order to vibration isolate the two from each other. To effectively utilize the region between the receiver assembly and the outer housing one or more microphones may be arranged in that region. 
         [0046]    Referring now to  FIG. 1  a receiver assembly  100  comprising two elongated receivers  101 ,  102  is depicted. The two receivers  101 ,  102  are elongated in the sense that they both have a length  104  which is significantly longer than the width  103 . Longitudinal centre lines  111 ,  112  are associated with each of the two receivers  101 ,  102 , respectively. As seen in  FIG. 1 a    the elongated receivers  101 ,  102  are connected in an in-line configuration with coinciding centre lines  111 ,  112  and a mechanically rigid connection  109 . The in-line configuration of the two receivers  101 ,  102  ensures that the receiver assembly as a whole has an elongated shape. This is advantageous in that the receiver assembly then fits into the ear-canal of a human being. 
         [0047]    In  FIG. 1 b    two elongated receivers  105 ,  106  are spatially shifted in a direction being essentially perpendicular to the longitudinal centre lines  113 ,  114 . However, the receiver assembly still forms an elongated receiver assembly. As depicted in  FIG. 1 b    the respective longitudinal centre lines  113 ,  114  are not coinciding. However, the centre lines  113 ,  114  are still essentially parallel. Similar to the receivers of  FIG. 1 a    the receivers  105 ,  106  have an elongated shape by having a length  108  which is significantly longer than the width  107 . The receivers  105 ,  106  are connected via a mechanically rigid connection  110 . 
         [0048]    As previously addressed the elongated receivers may be identical receivers or different receivers. Moreover, the type and thereby functioning of the receivers may be different. Thus, armature receivers, moving coil receivers and electrostatic receivers may be combined to comply with certain audio demands. It should also be noted that the receiver assembly may involve more than two receivers. 
         [0049]      FIG. 2  shows receiver configurations similar to those depicted in  FIG. 1 . However, instead of being connected via a mechanically rigid connection the receivers of  FIG. 2  are connected via a flexible, and thereby a vibration isolating, arrangement.  FIG. 2 a    shows an in-line configuration  200  involving two elongated receivers  201 ,  202  with coinciding centre lines  211 ,  212 . A flexible connection arrangement  209  connects the two elongated receivers  201 ,  202 . Again, the receivers  201 ,  202  have an elongated shape by having a length  204  which is significantly longer than the width  203 . 
         [0050]      FIG. 2 b    shows a pair of spatially shifted receivers  205 ,  206  where the respective centre lines  213 ,  214  are off-set relative to each other. Despite being spatially shifted in a direction being essentially perpendicular to the centre lines  213 ,  214 , said centre lines  213 ,  214  remain essentially parallel. A flexible connection arrangement  210  connects the two elongated receivers  205 ,  206 . 
         [0051]    In the configurations depicted in  FIGS. 2 a  and 2 b    the role of the flexible connection arrangements  209 ,  210  is to vibration isolate the elongated receivers from each other. The flexible connection arrangements  209 ,  210  can be implemented in various ways, such as by applying a membrane structure. The membrane structure will ensure that receiver generated vibrations from one elongated receiver are prevented from reaching and thereby influencing the performance of another receiver of the assembly. Again, the elongated receivers may be identical or different types of receivers. 
         [0052]    Referring now to  FIG. 3  a receiver assembly  300  with angled receivers  301 ,  302  is depicted. As illustrated in  FIG. 3 a    the longitudinal centre lines  307 ,  308  form an angle relative to each other. This angled is defined by the wedge-shaped connection arrangement  303  being positioned between the elongated receivers  301 ,  302 . The wedge-shaped may form a mechanically rigid connection or a flexible, and thereby vibration isolating connection. The two elongated receivers  301 ,  302  may be angled 5-45 degrees, such as 5-40 degrees, such as 5-35 degrees, such as 5-30 degrees, such as 5-25 degrees, such as 5-20 degrees, such as 5-15 degrees, such as 5-10 degrees relative to each other. Despite this angling the receiver assembly still defines an elongated structure being suitable for being positioned in an ear-canal of a human being.  FIG. 3 b    shows a configuration where the two elongated receivers  304 ,  305  are angled and spatially shifted relative to each other. Similar to  FIG. 3 a    the angling in  FIG. 3 b    is defined by the wedge-shaped connection arrangement  306  which may be a mechanically rigid connection or a flexible, and thereby vibration isolating connection. 
         [0053]    Referring now to  FIG. 4  a box-in-a-box arrangement  400  is depicted. As seen in  FIG. 4  an elongated receiver assembly comprising two connected receivers  401 ,  403  is positioned inside an outer housing  403 . The two elongated receivers  401 ,  402  are connected via connection  404  which may be a mechanically rigid connection or a flexible, and thereby vibration isolating connection. In  FIG. 4  the elongated receivers  401 ,  402  are connected in an in-line configuration. It should be noted however that the receivers  401 ,  402  could be angled and/or shifted as well without departing from the box-in-a-box arrangement depicted in  FIG. 4 . The box-in-a-box arrangement  400  depicted in  FIG. 4  is a vibration isolated arrangements where the receiver assembly is vibration isolated from the outer housing  403  via suspension members  405 ,  406 ,  407 ,  408 . Thus, receiver generated vibrations originating from one of the receivers  401 ,  402  are prevented from reaching the outer housing  403  due to the suspension of the receiver assembly inside the outer housing. As illustrated in  FIG. 4  the presence of the suspension members  405 ,  406 ,  407 ,  408  between the receiver assembly and the outer housing  403  provide available free space regions  409 ,  410  between the receiver assembly and the outer housing  403 . 
         [0054]    It should be noted that instead of a receiver assembly involving two connected receivers  401 ,  402  a single receiver may be arranged within the outer housing  403 . 
         [0055]    Referring now to  FIG. 5  two microphone units  508 ,  509  are secured to the outer housing  512  via connections  510 ,  511 , respectively. Similar to  FIG. 4 , the box-in-a-box arrangement shown in  FIG. 5  comprises a receiver assembly involving two connected receivers  501 ,  502 . The receivers  501 ,  502  and connected via connection  503  which may be a mechanically rigid connection or a flexible, and thereby vibration isolating connection. Suspension members  504 ,  505 ,  506 ,  507  are provided for vibration isolation of the receiver assembly from the outer housing  512 . In  FIG. 5  the suspension members  504 ,  505 ,  506 ,  507  are positioned above and below the receiver assembly. Alternatively or in combination therewith the suspension members  504 ,  505 ,  506 ,  507  could be positioned on the sides of the receiver assembly. The microphone units  508 ,  509  may be MEMS microphones and/or electret microphones and the connections  510 ,  511  may be mechanically rigid connections or vibration isolating connections. In  FIG. 5  the microphone units  508 ,  509  are positioned above the receiver assembly. Other suitable positions for the microphone units  508 ,  509  are for example below the receiver assembly. Sound inlet openings (not shown) are provided in the outer housing  512  so that incoming sound is able to reach the microphone units  508 ,  509 . 
         [0056]    Again, it should be noted that instead of a receiver assembly involving two connected receivers  501 ,  502  a single receiver may be arranged within the outer housing  512 . 
         [0057]    As previously mentioned the receiver assembly of the present invention may comprise two or even more receivers. These receivers may be identical receivers or different receivers. In case of using two identical receivers in an in-line configuration receiver generated vibrations tend to cancel out. Two identical receivers may be oriented in the manner, i.e. with the motor and membrane moving in essentially the same direction. Alternatively, two identical receivers may be oriented in an opposite manner, i.e. with the motor and membrane moving in essential opposite directions. 
         [0058]    In case of different receivers, for example a tweeter/woofer configuration, a desired or even an enhanced acoustical performance may be obtained. In addition to the different frequency response the receivers may be different in terms size, shape, functionality, vibration properties and/or applied motor type. In case of a box-in-a-box configuration different receivers may be suspended differently. For example, in the before mentioned tweeter/woofer configuration the woofer will typically not be suspended. Moreover, the orientation of the woofer is not critical from a vibration perspective. The tweeter however will often be suspended in a vibration isolating suspension arrangement. 
         [0059]    Regarding the microphone units one or more microphone units may be applied in relation to the box-in-a-box configuration. As already mentioned the microphone units may be MEMS microphones and/or electret microphones with either open or closed rear volumes, cf.  FIGS. 6 a  and 7 a   . In case of two microphone units these may have an open rear volume ( FIG. 6 b   ), have separate rear volumes ( FIG. 7 b   ) or share a closed rear volume ( FIG. 8 ). 
         [0060]    Referring now to  FIG. 6 a    a box-in-a-box configuration is depicted. As seen in  FIG. 6 a    a receiver assembly  602  is arranged within an outer housing  601 . The receiver assembly  602  and the outer housing  601  are vibration isolated from each other via four suspension members  603 - 606 . A single MEMS microphone unit  607  comprising a MEMS microphone  608  having a sound inlet (indicated by arrow  610 ) and a signal processing circuit  609  is secured to or integrated with the outer housing  601 . The MEMS microphone  608  and the signal processing circuit  609  are connected via an electrical connection  611 , such as a wire. The MEMS microphone unit  607  has an open rear volume  612 . 
         [0061]      FIG. 6 b    also depicts a box-in-a-box configuration. As seen in  FIG. 6 b    a receiver assembly  613  is arranged within an outer housing  614 . Again, the receiver assembly  613  and the outer housing  614  are vibration isolated from each other via four suspension members  615 - 618 . Two MEMS microphone units  619 ,  620  each comprising a MEMS microphone  621 ,  622  having a sound inlet (indicated by arrows  623 ,  624 ) and a signal processing circuit  625 ,  626  are secured to or integrated with the outer housing  614 . Again, electrical wires connect the MEMS microphones and the signal processing circuits. 
         [0062]    Both the single MEMS microphone unit of  607   FIG. 6 a    and the two MEMS microphone units  619 ,  620  of  FIG. 6 b    have open rear volumes  612 ,  627 . 
         [0063]    In  FIG. 7 a    a single MEMS microphone unit  707  having a closed rear volume  708  is depicted. The closed rear volume  708  is defined by the separation wall  709 . The MEMS microphone unit  707  comprises a MEMS microphone  710  having a sound inlet as indicated by arrow  712  and a signal processing circuit  711 . Generally,  FIG. 7 a    depicts a box-in-a-box configuration with a receiver assembly  702  arranged within an outer housing  701  in a vibration isolating arrangement via suspension elements  703 - 706 . 
         [0064]      FIG. 7 b    shows two MEMS microphone units  719 ,  720  each having a closed rear volume  727 ,  728 . The closed rear volumes  727 ,  728  are defined by the respective separation walls  729 ,  730 . Each of the MEMS microphone units  719 ,  720  comprises a MEMS microphone  721 ,  722  having a sound inlet as indicated by arrows  725 ,  726  and a signal processing circuit  723 ,  724 . Similar to  FIG. 7 a   ,  FIG. 7 b    depicts a box-in-a-box configuration with a receiver assembly  714  arranged within an outer housing  713  in a vibration isolating arrangement via suspension elements  715 - 718 . 
         [0065]      FIG. 8  shows two MEMS microphone units  807 ,  808  sharing a closed rear volume  815 . The shared closed rear volume is defined by the separation wall  816 . Each of the MEMS microphone units  807 ,  808  comprises a MEMS microphone  809 ,  810  having a sound inlet as indicated by arrows  813 ,  814  and a signal processing circuit  811 ,  812 . Similar to  FIG. 7 ,  FIG. 8  depicts a box-in-a-box configuration with a receiver assembly  802  arranged within an outer housing  801  in a vibration isolating arrangement including suspension elements  803 - 806 .