Abstract:
An antenna for wireless communication of a hearing device is shielded efficiently in a simple manner from electrical and magnetic interference fields by providing a coil apparatus and a shielding apparatus. The shielding apparatus has a flexible substrate as its main body and is formed as a single piece. The shielding apparatus is subdivided into three sections by two slits having ends not reaching the edge of the substrate. The coil apparatus is inserted through the two slits in the shielding apparatus in such a way that each of the sections only partially surrounds the coil apparatus in a circumferential direction. The sleeve-type shield can thus be applied on the coil apparatus in a simple manner. A method for manufacturing an antenna for a hearing device is also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority, under 35 U.S.C. §119, of German Patent Application DE 10 2014 203 169.9, filed Feb. 21, 2014; the prior application is herewith incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to an antenna for a hearing device with a substantially cylindrical coil apparatus as an electromagnetic transmitting and/or receiving unit and a shielding apparatus that surrounds the coil apparatus and has a flexible substrate as its main body. Furthermore, the present invention relates to a method for manufacturing an antenna for a hearing device. 
         [0003]    Hearing apparatuses often have antennas for wireless near-field transmission. Such transmissions are used, for example, to communicate with ancillary devices or with devices of the same type (e.g. in a binaural hearing device system). Such a hearing apparatus refers to any device which can be worn on the ear and which generates an auditory stimulus, in particular a hearing device, headset, headphones and the like. 
         [0004]    Hearing devices are wearable hearing apparatuses which are used to assist the hard-of-hearing. In order to accommodate numerous individual requirements, various types of hearing devices are available such as behind-the-ear (BTE) hearing devices, hearing devices with an external receiver (RIC: receiver in the canal) and in-the-ear (ITE) hearing devices, for example concha hearing devices or completely-in-the-canal (ITE, CIC) hearing devices as well. The hearing devices listed as examples are worn on the outer ear or in the auditory canal. Bone conduction hearing aids, implantable or vibrotactile hearing aids are also available on the market. The damaged hearing is stimulated either mechanically or electrically with those devices. 
         [0005]    Hearing devices in principle have the following key components: an input transducer, an amplifier and an output transducer. The input transducer is generally a sound receiver, e.g. a microphone, and/or an electromagnetic receiver, e.g. an induction coil. The output transducer is usually implemented as an electro acoustic converter, e.g. a miniature loudspeaker, or as an electromechanical converter, e.g. a bone conduction receiver. The amplifier is usually integrated into a signal processing unit. That basic structure is illustrated in  FIG. 1  using the example of a behind-the-ear hearing device. One or more microphones  2  for picking up ambient sound are incorporated in a hearing device housing  1  to be worn behind the ear. A signal processing unit  3 , which is also integrated in the hearing device housing  1 , processes and amplifies the microphone signals. The output signal of the signal processing unit  3  is transmitted to a loudspeaker or receiver  4 , which outputs an acoustic signal. The sound is optionally transmitted, by way of a sound tube which is fixed with an otoplastic in the auditory canal, to the eardrum of the device wearer. Power for the hearing device and, in particular, for the signal processing unit  3  is supplied by a battery  5  which is also integrated in the hearing device housing  1 . 
         [0006]    Antennas are necessary on the receiver as well as on the transmitter for wireless transmission. Unshielded antennas are sensitive to both electrical (E field) and magnetic (H field) interferences generated by nearby electronic components. Such interference fields or interferences result in a deterioration of the wireless payload signal in such a way that the communication signal from the transmitter may not be received by the receiver or may only be received with poor quality. In that case the performance of the wireless communication system is reduced. 
         [0007]    In order to avoid degradations of that kind, unshielded antennas for wireless connections are generally spaced apart from electronic components that emit electrical and magnetic interferences. That compromises the freedom in the positioning of the antennas in the hearing apparatus or hearing device, in particular the behind-the-ear hearing device. However, with several hearing devices it is necessary for structural reasons that the antenna for wireless transmission be disposed closer to an electronic component that produces an electrical or magnetic interference field. In such cases, shields in the form of covers or small boxes are generally provided. Specifically those electronic components which produce the undesirable electrical and magnetic interference fields are shielded or encased. Due to the different types of hearing apparatuses and electronic components thereof, numerous shielding covers of different sizes and constructions must be provided. 
         [0008]    A surface-mounted coil for wireless transmission is known from U.S. Pat. No. 7,592,964 B2. The coil has a wire that is wound around a core. The coil also has a shielding layer that is wound around a central section of the core so that the windings are covered. The shielding layer has a shielding pattern formed from conductors and a contact section for contacting with ground potential. 
       SUMMARY OF THE INVENTION 
       [0009]    It is accordingly an object of the invention to provide an antenna for a hearing apparatus and a corresponding manufacturing method, which overcome the hereinafore-mentioned disadvantages of the heretofore-known antennas and methods of this general type and in which the antenna can be fitted with a shielding apparatus in a simple manner. 
         [0010]    With the foregoing and other objects in view there is provided, in accordance with the invention, an antenna for a hearing device, comprising a substantially cylindrical coil apparatus as an electromagnetic transmitting and/or receiving unit, a shielding apparatus surrounding the coil apparatus and having a flexible substrate as its main body, the shielding apparatus being formed as a single piece and being subdivided into three sections by two slits having ends which do not extend to or reach the edge of the substrate, and the coil apparatus being inserted through the two slits in the shielding apparatus in such a way that each of the sections only partially surrounds the coil apparatus in a circumferential direction. 
         [0011]    With the objects of the invention in view, there is also provided a method for manufacturing an antenna for a hearing device, which comprises providing a substantially cylindrical coil apparatus as an electromagnetic transmitting and/or receiving unit, providing a shielding apparatus for shielding the coil apparatus, providing the shielding apparatus with a main body being a flexible substrate, forming the shielding apparatus as a single piece being subdivided into three sections by two slits having ends which do not extend to or reach the edge of the substrate, and inserting the coil apparatus through the two slits in the shielding apparatus in such a way that each of the sections only partially surrounds the coil apparatus in a circumferential direction. 
         [0012]    Advantageously therefore, in order to shield a coil apparatus, a shielding apparatus on the basis of a flexible substrate is used that is divided by two slits into three sections. For the assembly, only the coil apparatus is then passed through the two slits so that the shielding apparatus is placed onto and partially surrounds the coil apparatus. A middle zone of the shielding apparatus substantially surrounds the coil apparatus on a section of its external circumference or periphery, while the outer two sections of the shielding apparatus surround the coil apparatus at opposite circumferential zones. Thus, on one hand, a very simple manufacture of the shielding apparatus and on the other hand a less laborious assembly onto the coil apparatus, are possible. 
         [0013]    In accordance with another embodiment variant of the invention, the shielding apparatus has an electrically connected conductor structure in all three sections. In this case shielding is provided by all three sections. Alternatively, the conductor structure can also be provided, for example, in the central section only. 
         [0014]    In accordance with a further embodiment variant of the invention, the conductor structure can have numerous parallel conductors. They can be manufactured easily and provide an efficient shielding effect. 
         [0015]    In accordance with an added embodiment variant of the invention, the slits in the shielding apparatus are disposed parallel to each other and the conductors are disposed parallel to the slits. This has the advantage that the position of the slits can be changed without having to change the conductor structure itself. In this way shielding apparatuses of different lengths can be produced for coil apparatuses of various lengths using one and the same strip material, simply by cutting off and by then introducing the slits. 
         [0016]    In accordance with a further embodiment variant of the invention, the three sections of the shielding apparatus are disposed one behind the other in an axial direction of the substantially cylinder-shaped coil apparatus, and the outer two of the three sections each have a first contact tab for directly contacting a ground terminal, wherein the contact tabs are electrically connected to conductors of the shielding apparatus. In this way the contact tabs for the shielding apparatus are positioned on the external periphery of the antenna, with the result that the shielding apparatus can be connected to ground easily. 
         [0017]    In accordance with an added embodiment variant of the invention, in addition the outer two of the three sections can each have a second contact tab for directly contacting a conductor of the coil apparatus. Where the first and second contact tabs are then turned outward and are as parallel as possible, this results in an SMD-type antenna. Thus, a shielded antenna can be provided for an economically advantageous SMD production. 
         [0018]    In accordance with an additional embodiment variant of the invention, the shielding apparatus can have a flexible circuit board with the flexible substrate. Flexible circuit boards of this type are manufactured at low cost and can be obtained in bulk. In particular, the flexible circuit board can be a printed circuit board. 
         [0019]    In accordance with a concomitant embodiment variant of the invention, for the manufacture of an SMD component it is especially advantageous for the coil to have a core that has a segment of a circle as its cross-section. Thus, the core has a flat side parallel to its axis. This flat side can be used to place the contact tabs of the shielding apparatus in parallel so that a stable SMD component is obtained. 
         [0020]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0021]    Although the invention is illustrated and described herein as embodied in an antenna with a shielding apparatus and a manufacturing method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0022]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0023]      FIG. 1  is a diagrammatic, top-plan view showing a basic structure of a hearing device according to the prior art; 
           [0024]      FIG. 2  is a top-plan view of a flexible disk-shaped shielding apparatus; 
           [0025]      FIG. 3  is a top-plan view of a coil apparatus in an unshielded state; 
           [0026]      FIG. 4  is a top-plan view of the coil apparatus of  FIG. 3  inserted into the shielding apparatus of  FIG. 2 ; 
           [0027]      FIG. 5  is a long side-elevational view of the antenna of  FIG. 4 ; 
           [0028]      FIG. 6  is an end-elevational view of the antenna of  FIG. 4 ; and 
           [0029]      FIG. 7  is a lower side-elevational view of the antenna of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Referring now to the figures of the drawings in detail and first, particularly, to  FIG. 1  thereof, there is seen an example of a hearing apparatus and, in particular, a hearing device which can be fitted with an antenna for the wireless transmission of signals. An antenna of this kind is outlined from various side views in  FIGS. 4 to 7 .  FIGS. 2 and 3  are intended to clarify the manufacturing method. 
         [0031]    If, for example, an antenna for wireless transmission is to be capable of being disposed in a hearing device near to an amplifier component, the antenna should be suitably shielded to be able to ensure a high quality of wireless transmission. It is critical for shielding to be able to ward off the E field and H field to a sufficient extent. At the same time the shielding should be easy to manufacture and easy to install. It is expedient furthermore if the shielding can use one antenna coil (coil apparatus) with different structural types in order to be able to work with instruments of lower-cost platforms as well. Coil apparatuses for hearing devices have a typical length of 5 to 6 mm, for example. It would additionally be advantageous if the shielded antennas were available as SMD components. 
         [0032]    In order to meet all of these requirements (or even just one or more thereof), the exemplary antenna according to the present invention is proposed, which is illustrated in more detail in  FIGS. 2 to 7 . However certain details can also be dispensed with herein, in particular those that characterize an SMD component. 
         [0033]      FIG. 2  shows a shielding apparatus  10  before assembly. The shielding apparatus  10  is a disk-shaped structure with a flexible substrate  11 . This substrate  11  can be a polyimide film, for example. In this case two slits  12  and  13  are introduced into the substrate and subdivide the rectangular substrate into three sections  14 ,  15  and  16 . The two slits  12  and  13  extend in this case parallel to each other and parallel to two opposing sides of the rectangular substrate  11 . The slits  12  and  13  do not extend to the edge of the substrate. This means that the ends of the slits  12  and  13  are located in the interior of the substrate  11 . This means furthermore that the sections  14 ,  15  and  16  of the substrate  11  are connected to each other as a single piece. Only a notional or imaginary extension of each of the slits  12  and  13  produces the respective section boundaries between these sections  14 ,  15  and  16 . 
         [0034]    A conductor structure  17  is introduced into the substrate  11  or is applied on the substrate  11 . It is preferably introduced into or applied on the largest zone of the middle section  15  between the two slits  12  and  13 . In the example in  FIG. 2  the conductor structure  17  is disposed almost above the entire central zone of the middle section  15 . Only edge zones thereof are free, for example to be able to subsequently introduce the slits  12  and  13  into the substrate  11 . 
         [0035]    The substrate  11  of the shielding apparatus  10  can also have a different shape than a rectangle. In addition the slits  12  and  13  can also be disposed diagonally. Furthermore, more than two slits, e.g. four slits, can also be provided. Although the slits in the example of  FIG. 2  extend in a straight line, they are not restricted to this configuration. 
         [0036]    In the example of  FIG. 2 , conductors  18  of the conductor structure  17  extend parallel to the long sides of the rectangular substrate  11 . This can be advantageous for certain applications. In order to suit other requirements it may be more expedient under certain circumstances if the plurality of conductors of the conductor structure extend parallel to each other, but also parallel to the slits  12  and  13  wherein, for example, they can be connected electrically by way of a conductor extending continuously along a long side of the substrate  11 . In other words, the conductor extends across the section boundaries. Consequently the shielding apparatus  10  can be punched or cut out from a strip material to any desired length, and with this constellation the slits  11 ,  12  can be positioned between any conductors as desired. This results in a high degree of flexibility and economical manufacturing costs. 
         [0037]      FIG. 3  shows a coil apparatus  19  that represents the electromagnetic antenna itself. It has a substantially cylinder-shaped core  20  and a coil  21  around its external circumference or periphery. In order to maintain the flux, the core  20  protrudes significantly beyond the ends of the coil  21 . 
         [0038]    The shielding apparatus  10  is spread apart at the slit  12  for assembly of the shielding apparatus  10  on the coil apparatus  19 . The coil apparatus  19  is then pushed through the spread-apart gap in the slit  12 . Subsequently or simultaneously the second slit  13  is spread apart and then the coil apparatus  19  is also fed through the gap in the second slit  13 . The result of the assembly can be seen in  FIGS. 4 to 7 . 
         [0039]    It can be seen in the top view of  FIG. 4  that the ends of the core  20  of the coil apparatus  19  protrude from the slits  12  and  13  of the shielding apparatus  10 . Viewed from above, the coil  21  of the coil apparatus  19  is obscured by the middle section  15  of the shielding apparatus  10 . 
         [0040]    The long-side view of  FIG. 5  shows that the middle section  15  of the shielding apparatus  10  surrounds the coil apparatus  19  on the top side, while the outer sections  14  and  16  of the shielding apparatus  10  only abut against the outer zones of the core  20  at the bottom. This is also confirmed by the end view of  FIG. 6 . There the section  15  of the shielding apparatus  10  fits precisely against the coil  21 , which in turn surrounds the core  20 . However, it is not necessary for the section  15  or the shielding apparatus  10  to fit precisely and without a gap against the coil  21  or the coil apparatus  19 . Instead, such a gap is generally expedient for the assembly and can be sealed with an adhesive retrospectively. 
         [0041]    Furthermore, as  FIG. 6  shows, the substantially cylinder-shaped core  20  of the coil apparatus  19  has a segment of a circle, rather than a circle, as its cross-section transverse to the longitudinal axis. The segment of a circle has a central angle of  320 ° , for example. This results in a bottom surface  22  for the core  20 . The outer sections  14  and  16  of the shielding apparatus  10  can be flush with this bottom surface  22 . At their lower side, i.e. the side facing away from the core  20 , the sections  14  and  16  each have a first contact tab  23  and a second contact tab  24 . These contact tabs  23 ,  24  represent conventional SMD contact pads. They can be made of copper, for example, and are spaced preferably at a slight distance from the substrate  11  at the section  14  or  16  so that they can be contacted easily by contact welding or reflow soldering. 
         [0042]    Finally, as can be seen from the lower-side view of  FIG. 7 , the middle section  15  between the slits  12  and  13  of the shielding apparatus  10  does not fully surround the coil apparatus  19  on its circumference so that this middle section  15  forms a sleeve on which a part of its shell is open. This partially open sleeve is then held together by the sections  14  and  16  on its ends. In the present example, the coil apparatus  19  is therefore not shielded in a downward direction in the vicinity of the coil  21 . 
         [0043]    In addition,  FIG. 7  shows a first contact tab  23  in each respective section  14  and  16 . The first contact tabs  23  are connected to the conductor structure  17  within the shielding apparatus  10 . They are typically connected to ground by using a soldering process. In principle it is sufficient if the shielding apparatus  10  has a single first contact tab  23 . 
         [0044]    In the present example the antenna, i.e. the coil apparatus  19 , is embodied together with the shielding apparatus  10  as an SMD component. For this reason it is necessary for contact pads to also be provided for the terminals of the coil  21 . The second contact pads  24  are therefore also located on the lower sides of the sections  14  and  16  adjacent the first contact pads  23  for ground. Terminals  25  of the coil  21  are connected, for example, to the second contact tabs  24  by using spot-welding. 
         [0045]    Provision is therefore made according to the invention for an antenna with a sleeve-shaped shield, wherein preferably a flexible, printed circuit board is applied around the coil apparatus. In this case the shielding layer is only partially wound around the antenna. 
         [0046]    The antenna with the sleeve-shaped shield is less sensitive to electrical and magnetic interferences than unshielded antennas, and therefore provides a better signal-to-noise ratio. Consequently, the distance for wireless communication between devices can be increased. 
         [0047]    The simple construction of the shielding apparatus enables its use for different coil apparatuses and thus for different hearing device models. It is therefore possible to dispense with individual shielding covers. This reduces the quantity of individual parts involved in hearing device assembly. Furthermore, the shield of the invention can be manufactured for the coils in mass production. In addition, bulky shield boxes for the amplifiers of hearing devices can be avoided with the coil shield of the invention, so that ultimately the hearing devices can be miniaturized.