Abstract:
The present invention relates generally to hearing aids and to methods of manufacturing hearing aids. The invention further relates to shells for hearing aids and methods of manufacturing thereof The invention, more particularly, relates to custom-made BTE hearing aids. A shell comprising a first part, and a second part, wherein said first part is adapted to fit the contour of the cleft between a pinna and the skull of an individual is provided. The shell may be part of a hearing aid ( 17 ) that is connected with a tube ( 9 ) in a first end and an earplug ( 20 ) in a second end. In a third aspect of the invention a method of preparing the shell is disclosed and in a fourth aspect a method of manufacturing a hearing aid is also disclosed.

Description:
RELATED APPLICATIONS The present application is a continuation-in-part of application No. PCT/DK2004/000899, filed on Dec. 22, 2004, in Demark and published as WO 2006/066570 A1. 
    
    
     BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to hearing aids and to methods of manufacturing hearing aids. The invention, more specifically relates to Behind-The-Ear (BTE) hearing aids and methods of preparing them. The invention, still more particularly, relates to custom-made BTE hearing aids.  
         [0003]     2. The Prior Art  
         [0004]     Behind-the-ear (BTE) hearing aids is a subgroup within the general group of hearing aids worn by the ear. Hearing aids supported entirely by the ear are normally divided into three classes: Behind-The-Ear (BTE) hearing aids, In-The-Ear (ITE) hearing aids and Completely-In-the-Canal (CIC) hearing aids. A BTE hearing aid is the largest type and basically incorporates a housing or a shell that is adapted for being placed partially above and partially behind the users outer ear (the pinna). The housing provides a platform and encapsulation for electronic and acoustic components, such as a battery, a microphone, and an amplifier. In some types, the housing also contains a miniature loudspeaker, in the hearing aid parlance usually referred to as a receiver, which connects to a tube for conveying the receiver output into the ear canal of the user. The tube ends in an earpiece that couples with the ear canal. The earpiece may comprise a soft standard plug or it may comprise a customized plug. In use the housing is placed behind the external ear, partially concealed. In some BTE&#39;s the housing extends into a hook that serves the purpose of resting the hearing aid housing. U.S. Pat. No. 6,228,020 shows a hearing aid with a faceplate and a shell customized to fit in the user&#39;s ear canal.  
         [0005]     WO-98/47319 shows a hearing aid for arrangement in a user&#39;s ear canal and including a shell customized to the users ear canal, components and a faceplate.  
         [0006]     DE-U-1784750 discloses a BTE hearing aid with an individually formed housing, which housing is molded by a method as is known from the field of dentistry, so as to fill the space between the pinna and the head of the user. In the housing there is a hearing aid connected to an ear piece by an air conduit. The disclosure gives no enablement regarding how to integrate hearing aid components into the housing.  
         [0007]     AT patent 194933 discloses a BTE hearing aid, wherein the housing is provided with exterior plastic moldings adapted to improve the seat. The housing may be provided with an aperture for threading through a side bar of a pair of glasses.  
         [0008]     BTE hearing aids offer space for large batteries, larger amplifiers, telecoils, dual microphones, push buttons and switches to change between various functions etc. Such features are difficult or impossible to implement in smaller types. BTE hearing aids also permit the arrangement of a microphone and a receiver with a mutual spacing that better permits controlling acoustic feedback from the receiver to the microphone. Some users may find BTE hearing aids more comfortable in wearing. Thus, many users find good reasons to prefer BTE hearing aids rather than ITE or CIC hearing aids.  
         [0009]     The state of the art BTE hearing aid comprises a standard housing that is curved to suit the general contour of the cleft between a pinna (left or right) and the skull of a user. The top part of the housing normally extends into a projecting hook that incorporates a sound conduit and provides a grip around the top part of the cleft between pinna and skull.  
       SUMMARY OF THE INVENTION  
       [0010]     It is an object of the invention to provide a method of manufacturing a hearing aid that is simple and that yields a hearing aid that is comfortable in use.  
         [0011]     It is a further object of the invention to provide a hearing aid that is simple in manufacture.  
         [0012]     It is a yet further object of the invention to provide a hearing aid that can be manufactured without requiring capital intensive equipment.  
         [0013]     It is a still further object to provide a hearing aid with excellent and comfortable retention on the user.  
         [0014]     The invention, in a first aspect provides a method of preparing a Behind-The-Ear hearing aid for an individual hearing aid user, said method comprising the steps of providing an impression having a first part and a second part, the first part being directly cast by contact with the cleft between the skull and a pinna of said user, and the second part being adapted to complete the impression, molding a shell using the impression as a form, cutting said shell, whereby to provide a housing that has an aperture encircled by an edge, providing a faceplate, which faceplate has an entrance opening, adhering said faceplate to said edge, providing a module for supporting an amplifier assembly and a battery compartment, and inserting and securing said module through said entrance opening, whereby to complete the Behind-The-Ear hearing aid.  
         [0015]     This provides an effective and accurate method for preparing a hearing aid that excels in fit and user comfort.  
         [0016]     Within the context of this disclosure the expression a custom shell signifies a shell that includes structure that has been adapted to an individual.  
         [0017]     As far as known to the inventor, within the context of commercial BTE hearing aids, customization has only been extended to the preparation of the earpiece, never to the housing.  
         [0018]     This hearing aid shell includes a part that is customized to fit the contour of the cleft between a pinna and the skull of an individual. This part will normally rest against corresponding parts of the cleft, and thereby provides for a shell that is superior in fit and comfort. The shell includes a second part that generally completes the shell but that is not necessarily adapted to rest in direct contact with the cleft of the user.  
         [0019]     The two parts may be manufactured integrally or they may be manufactured in separate stages and joined together by conventional means.  
         [0020]     According to embodiments, the shell may comprise an outlet. The outlet may be an opening for an acoustic output that can be conveyed by a tube to an ear plug inserted in the users ear canal, or it may be an electric lead or a connector for an electric output, that is fed to a receiver arranged spaced from the housing, e.g. in an earpiece, and close to the users ear canal.  
         [0021]     Preferably, the outlet is arranged in the second shell part. Keeping the outlet away from the part of the shell intended to rest against the users avoids compromising the fit.  
         [0022]     According to an embodiment, the shell may be extended into a hook, and the hook may accommodate the outlet. The hook may be partially customized to the user or it may be a standard shape, suitably arranged on the housing.  
         [0023]     According to an embodiment, the shell comprises a third part, which is adapted to fit a part of an arm of a spectacle frame. This provides a superior fit of the hearing aid for a user who wishes to wear spectacles and hearing aids at the same time.  
         [0024]     According to an embodiment, the shell may include a faceplate. The faceplate may be a standard plate with various components, possibly cut to match a contour of the custom shell, in order that the shell and the faceplate together will produce a coherent appearance. The faceplate may preferably be arranged in that part of the shell that is not adapted to contact the user directly.  
         [0025]     The invention, in a second aspect, provides a hearing aid comprising a housing, a faceplate and a module, wherein said housing is manufactured by providing an impression having a first part and a second part, the first part being directly cast by contact with the cleft between the skull and a pinna of said user, and the second part being adapted to complete the impression, molding a shell using the impression as a form, and cutting said shell, whereby to provide a housing that has an aperture encircled by an edge, wherein said faceplate has an entrance opening and is adhered to said housing at said edge, and wherein said module includes an amplifier assembly and a battery compartment, and is adapted for mounting in the housing by inserting and securing said module through said entrance opening.  
         [0026]     Further embodiments will appear from the dependent claims.  
         [0027]     Further objects, embodiments and advantages will appear from the detailed part of the specification. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]     The invention will now be described in more detail with reference to the accompanying drawings, where  
         [0029]      FIG. 1  illustrates a first step in preparation of a shell;  
         [0030]      FIG. 2  illustrates a hearing aid with a housing arranged in a low position behind the ear;  
         [0031]      FIG. 3  illustrates a hearing aid with a housing arranged in a medium position behind the ear;  
         [0032]      FIG. 4  illustrates a hearing aid with a housing arranged in a high position behind the ear;  
         [0033]      FIG. 5  shows a BTE hearing aid with a hook;  
         [0034]      FIG. 6  shows a shell for a BTE hearing aid and a faceplate;  
         [0035]      FIG. 7  shows a shell joined with a faceplate;  
         [0036]      FIG. 8  shows a BTE hearing aid wherein the faceplate is integrated in the shell;  
         [0037]      FIG. 9  shows an embodiment with a shell integrated with the faceplate and with a microphone entrance;  
         [0038]      FIG. 10  shows a shell before the electronic components having been mounted;  
         [0039]      FIG. 11  shows a hearing system comprising a hearing aid, a tube, a connecting element, and an ear plug;  
         [0040]      FIG. 12  shows a hearing aid system arranged adjacent a pair of spectacles;  
         [0041]      FIG. 13  shows a hearing aid system according to another embodiment, arranged adjacent a pair of spectacles;  
         [0042]      FIG. 14  shows a close-up of a shell with an indentation for spectacles;  
         [0043]      FIG. 15  represents a hearing aid according to  FIG. 12  but placed in the cleft between the skull and pinna; and  
         [0044]      FIG. 16  shows a hearing aid housing in longitudinal section. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0045]     A way of preparation of a shell:  
         [0046]     The first step in preparing of a shell comprises providing a cast impression  14  in the area behind the ear, i.e. in the cleft between the skull  32  and pinna  26 , e.g. as the one illustrated in  FIG. 1 . During the casting it is important not to strain or deform pinna in order that the impression will match the actual space of the cleft behind the ear while the ear and the pinna are relaxed. If the hearing aid user normally wears spectacles, an impression of part of an armature of a spectacle frame can be made in the cast impression  14 .  
         [0047]     The cast impression includes a surface portion directly cast by contact with the user and another surface portion that completes the impression and that has not been in direct contact with the user.  
         [0048]     The second step in the preparation is to trim the impression to a desired form. During this second step the impression is waxed and a silicone control form is made. The control form is used to trim the impression further in order to make the final version of the impression. A dummy may be used to determine where the impression should be trimmed. The third step in the preparation is to wax and trim the final impression and the fourth step is to fill the form with an acrylic e.g. beige photoplast and irradiate the form with ultraviolet light, so that the acrylic hardens to a shell. In a fifth step the un-hardened acrylic in surplus is removed and the remaining shell is cut so as to leave a shell of a suitable size with a view to the desired size of the BTE housing and with a planar aperture.  
         [0049]     In a further step, a faceplate is adhered to an edge of the aperture and any protruding parts of the faceplate are cut off  
         [0050]     Further steps may be added in the preparation of the shell, such as a step of drilling a sound outlet.  
         [0051]     Examples of the BTE hearing aids with housings that are positioned various places behind the ear are shown in the  FIGS. 2-5 . The size of housing and thus the shell is selected with a view to the electronics to be mounted inside. If e.g. the hearing aid is to be used for mild to moderate hearing losses, electronic components corresponding to those available for Completely-In-the-Canal, CIC, hearing aids can be used.  
         [0052]     The electronic components, e.g. microphone, signal processor and receiver, may be mounted through the battery opening. A sound tube may be connected by one end to a receiver while the other end is pulled through a sound outlet in the shell and connected to an earplug. Alternatively, if e.g. the hearing aid is to be used for severe hearing losses, the BTE housing may be connected by an electrical wire to a receiver in an earplug, thereby permitting a higher sound output without causing feedback.  
         [0053]     In  FIG. 2-4  the housing is connected with a connecting element  8  on a tube  9 , the tube  9  having a first bend  18  around the top of the pinna of the users ear directing it into the concha of the ear and a second bend  19  to direct an end of the tube into the ear canal of the user. The tube is resilient and assists to keep the housing in a fixed position behind the ear and the earplug  20  in a fixed position in the ear canal.  
         [0054]      FIG. 5  shows a custom made BTE hearing aid wherein the forward part of the housing is formed as a hook  12  around the top of the ear and a tube  9  is fitted through the outlet opening of the housing.  
         [0055]      FIG. 6  shows a shell  25  for a BTE hearing aid with a corresponding faceplate  3 . The shell  25  has an aperture  1  and an outlet opening  2 . The faceplate  3  has a prefabricated entrance opening  4  for mounting a battery compartment, and the dotted line  5  indicates the final contour of the faceplate  3  when mounted onto the shell  25 . The faceplate  3  may e.g. be mounted by gluing the faceplate  3  and the shell  25  together. After gluing, the faceplate is trimmed by cutting away the parts protruding beyond the shell aperture. The electronic components are mounted in the shell through the entrance opening after trimming, e.g. as described in WO 98/47319.  FIG. 7  shows the shell  25  joined with the faceplate  3 , a battery door  6  in the faceplate, and the electronic components, such as a microphone, a receiver  7 , an electronics module  35  including a signal processor and a telecoil  37 . The shell  25  is connected to a tube  9  via a connecting element  8 .  
         [0056]     The shell comprises a first part  23  that matches a surface of the user and a second part  24 , distinguished from the first part by demarcation line  36 , which completes the shell. The second part generally includes a faceplate and a transition area connecting the faceplate to the first part. Thus, the first part is fully customized to the user, the second part is customized to match the first part along a selected contour, and the faceplate may be a standard shape.  
         [0057]     In an alternative embodiment the receiver is placed in the ear plug  20  and connected to the other electrical components in the shell  25  by a wire  29  in the tube  9 , thereby allowing a higher sound output ( FIG. 13 ). Another design option for adapting the hearing aid for a high sound output is by creating a larger shell  25  and arranging the microphone and the receiver with a mutual spacing so as to decouple feedback inside the housing.  
         [0058]      FIG. 8  shows a BTE hearing aid wherein the faceplate is integrated in the shell  25 . All the electronic components are mounted through a hole in the shell  25  corresponding to the entrance opening in  FIG. 8 .  
         [0059]      FIG. 9  shows another embodiment of the invention wherein the shell is integrated with the faceplate and has a microphone entrance  10  to which the microphone  11  is mounted to the shell  25 . All the electronic components are mounted through an opening in the shell  25  corresponding to the entrance opening  4  in  FIG. 6 .  
         [0060]      FIG. 10  shows a shell  25  before the electronic components are mounted through the entrance opening  4 . The entrance opening  4  corresponds to an opening for a battery compartment and for other details, e.g. as shown in WO 98/47319.  
         [0061]      FIG. 11  shows a hearing system  30  comprising a hearing aid  17  a tube  9  and a connecting element  8  and an ear plug  20 . A receiver may be arranged in the hearing aid  17  or it may be arranged in the earplug  20 . If the receiver is arranged in the earplug  20 , a higher output can be achieved without feedback, especially if a closed earplug  20  is used, in this case the receiver may be connected to the electronic components in the hearing aid  17  by a wire  29  in the tube  9 .  
         [0062]     The tube, or at least a part of it, is semi-rigid or resilient in order that the tube may also serve the purpose of resting the hearing aid on the external ear of the user. The earpiece is adapted, e.g. through resilience or customization to the users ear, to rest in the meatus of the ear canal.  
         [0063]     The hearing aid comprises an ear plug for contacting the meatus of the users ear canal, a contact element for resting against an inside of the users tragus, and a fixture for holding the ear plug and the contact element together, the fixture having means for adjusting the spacing between the plug and the contact element. This type of plug provides a comfortable, partial support for the earpiece and is adapted to direct sounds amplified by the hearing aid towards the users ear canal. The support is complemented by the contact element, which rests against another part of the ear. The fixture permits adjusting the spacing between the plug and the contact element and thereby permits adapting the hearing aid to different sizes of ears, or to different preferences regarding pretension. The adjustment facility permits customizing the ear plug in order that it may accommodate a wide variety of users.  
         [0064]      FIG. 12  shows a hearing aid system  30  comprising a hearing aid  17 , a tube  9  and an open earplug  20 . The hearing aid  17  is adapted for a user wearing spectacles by an indentation  16  in the shell  25 . Likewise, the hearing aid system  30  showed in  FIG. 13  also comprises a shell  25  with an indentation  16  for an arm  27  of a pair of spectacles, the hearing aid system  30  further having a receiver in the earplug  20 , which is connected to the hearing aid by a wire  25 .  
         [0065]      FIG. 14  shows a close-up of a shell  25  with an indentation  16  for spectacles. In this embodiment, the shell comprises a first part  23  customized to the pinna and the skull of the user, a part, i.e. the indentation  16 , customized to a shape of the spectacles, and a part, generally designated the second part  24 , that completes the shell.  
         [0066]      FIG. 15  represents a hearing aid  17  according to  FIG. 12  when placed in the cleft between the skull  32  and pinna  26 . In the detailed picture a dotted line connects the first lobe  33  and the second lobe  34 , the line indicating the contour of the skull. An indentation  16  like the one for the hearing aid system shown in  FIG. 13  appears if lobe  33  is removed. Other forms of an indentation  16  in the shell  25  appear by e.g. removing lobe  34  or both lobe  33  and lobe  34 .  
         [0067]      FIG. 16  shows a shell  25  joined with a connecting element  8  and a tube  9  via a bushing  13 . The connecting element  8  has interaction means  21  for joining the shell to the bushing  13 . Alternatively the connecting element  8  may be connected directly to the shell  25  e.g. by gluing the connecting element  8  to the shell  25 . In another embodiment the bushing  13  is integrated in the shell  25 .