Abstract:
A bone conduction hearing aid includes an in-the-ear (ITE) component including a transducer that is carried by the ITE component and positioned in the concha of the ear when in use. A vibrationally conductive structural member of the ITE component conducts vibration produced the transducer into the ear canal and such vibrations are transferred through a housing of the transducer. From there, the vibrations are transferred to a cochlea of the user by way of the mastoid bone, enabling enhanced hearing perception in patients with hearing loss.

Description:
FIELD 
     This disclosure relates generally to hearing aids. More particularly, the present invention relates to a bone conduction hearing assistance device having a transducer which is placed in the concha of the ear. 
     BACKGROUND 
     For many hearing loss patients, bone conduction hearing aids offer a better solution than more conventional acoustic/air transmitting hearing aids. Indeed, for some patients bone conduction hearing aids offer the only solution. Bone conduction hearing assistance generally involves vibration of the patient&#39;s mastoid bone to improve hearing perception. In a typical bone conduction hearing aid, sound sensed by a microphone is converted to an electrical signal and amplified. The amplified signal is then received by a small transducer which vibrates the mastoid bone. Strategic placement of the transducer on the user is essential in order to achieve optimal results. For example, with some bone conduction hearing aids the transducer is placed against the skin behind the ear, while with others the transducer is placed on the forehead. Still others require surgical implantation of the transducer directly into the mastoid bone for better transmission of vibration. However, all of these approaches have significant disadvantages. 
     One particularly effective approach has been to mount the transducer on an in-the-ear (“ITE”) structural member. The structural member is inserted in the patient&#39;s ear canal so that the transducer is positioned adjacent the mastoid bone. While this approach has been shown to provide excellent vibration transfer characteristics, it is unavailable for patients with ear canals too small to receive the transducer, such as patients who suffer from congenital atresia—a condition where the ear canal is narrowed or, in some cases, entirely closed off from the ear drum. 
     In any case, space for accommodating parts within an earpiece shell of a hearing aid is very limited, particularly within ITE hearing aids. Thus, the efficient use of space within a structural member is a highly significant and limiting factor. 
     What is needed, therefore, is technology to increase the space for working components. What is also needed is technology to allow smaller earpiece shells of ITE hearing aids to be manufactured for persons with smaller ears and associated ear structures. 
     SUMMARY 
     The above and other needs are met by an apparatus for imparting vibrational energy to a user for assistance in hearing. The apparatus includes an earpiece shell having a cavity that defines an inner surface of the earpiece shell, and a transducer disposed at least partially within the earpiece shell. The transducer includes a housing engaged adjacent the inner surface of the earpiece shell, a spring member attached adjacent the housing, and a weight having a mass. The weight is attached adjacent the spring member and is movable within the cavity without contacting the earpiece shell. The transducer also includes means for initiating vibration disposed at least partially within the housing. The means for initiating vibration imparts vibrational energy to the weight to cause the weight to vibrate at a frequency which is dependent at least in part upon the mass of the weight attached adjacent the spring member. The earpiece shell conducts this vibrational energy to the user. Preferably, the housing of the transducer is press fit into the cavity of the earpiece shell. Preferably, the earpiece shell further includes an interference structure which controls a depth of insertion of the housing into the earpiece shell when the housing is press fit into the cavity. Preferably, the earpiece shell is formed from one or more acrylate polymers. In some embodiments, the means for initiating vibration further comprises a piezoelectric crystal. In other embodiments, the means for initiating vibration comprises a coil and a magnet. 
     In a related embodiment, the earpiece shell has a cavity that defines an inner surface of the earpiece shell. The cavity is configured for receiving the transducer housing in a press fit engagement. However, this embodiment includes only the earpiece shell itself without the internal parts with which it is configured for engagement. 
     In another related embodiment, the earpiece shell includes an aperture for receiving the housing of the transducer into the cavity and a cover plate configured for substantially covering the aperture. In these and other embodiments, the peak frequency of the vibrational energy ranges from about 500 Hz to about 3000 Hz when the mass is varied over a ratio of about 36:1. In these and other embodiments, the resonant frequency of the vibrational energy is preferably proportional to the inverse of the square root of the mass. 
     In some embodiments, the inner surface of the earpiece shell further includes at least two substantially flat inner sub-surfaces including a first inner sub-surface and a second inner sub-surface, wherein the housing of the transducer includes an outer surface including at least one substantially flat outer sub-surface with a first outer sub-surface, and wherein the first inner sub-surface fits tightly against the first outer sub-surface. 
     In some embodiments, the inner surface of the earpiece shell further includes at least two substantially flat inner sub-surfaces including a first inner sub-surface and a second inner sub-surface. The housing of the transducer further includes an outer surface having at least one substantially flat outer sub-surface with a first outer sub-surface, wherein the first inner sub-surface is attached to the first outer sub-surface. 
     In another aspect, embodiments of the disclosure provide a method of altering the output frequency of an apparatus that imparts vibrational energy to a user for assistance in hearing. The apparatus includes an earpiece shell for conducting the vibrational energy to the user and a transducer disposed at least partially within the earpiece shell. The earpiece shell includes a cavity that defines an inner surface of the earpiece shell, and the transducer includes a first housing engaged adjacent the inner surface of the earpiece shell. The transducer also includes a first spring member attached adjacent the housing and a first weight having a first mass. The first weight is attached adjacent the first spring member and is movable within the cavity without contacting the earpiece shell. First means for initiating vibration are disposed at least partially within the first housing. The first means for initiating vibration imparts vibrational energy to the first weight to cause the first weight to vibrate at a frequency which is dependent at least in part upon the mass of the first weight attached adjacent the first spring member. The method includes the steps of (a) removing a first set of one or more components from the earpiece, wherein the first set of one or more components includes at least the first weight; and (b) adding a second set of one or more components to the earpiece to replace the first set of one or more components removed in step (a), wherein the second set of one or more components includes at least a second weight having a second mass, wherein the second mass is not equal to the first mass. 
     In a related embodiment, step (a) further includes removing one or more of the first housing, the first means for initiating vibration, and the first spring member; and step (b) further comprises adding one or more of a second housing, a second means for initiating vibration, and a second spring member to replace the one or more components removed in step (a). 
     In another aspect, embodiments of the disclosure provide a transducer for use within an earpiece shell. The transducer includes a housing configured for attachment adjacent an inner surface of an earpiece shell, a spring member attached adjacent the housing, a weight having a mass, and means for initiating vibration disposed at least partially within the housing. The means for initiating vibration imparts vibrational energy to the weight to cause the weight to vibrate at a frequency which is dependent at least in part upon the mass of the weight attached adjacent the spring member. A power source provides power to the means for initiating vibration. The transducer is configured so that the weight freely vibrates, based at least in part on the energy transmitted through the spring member, without coming into direct contact with any other solid object during operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features, aspects, and advantages of the present disclosure will become better understood by reference to the following detailed description, appended claims, and accompanying figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
         FIG. 1  shows a somewhat schematic view of a hearing aid apparatus including an in the ear (ITE) component and a behind the ear (BTE) component. 
         FIG. 2  shows a functional block diagram of typical hearing aid having an ITE transducer; 
         FIG. 3  shows a somewhat schematic cross-sectional view of a prior art version of an ITE hearing aid apparatus; 
         FIG. 4  shows a bottom view of a prior art transducer as depicted in  FIG. 3 ; 
         FIG. 5  shows a somewhat schematic cross-sectional view of an embodiment of an ITE hearing aid apparatus; 
         FIG. 6  shows a somewhat schematic cross-sectional view taken along line A-A of  FIG. 5 ; 
         FIG. 7A  shows a somewhat schematic view looking down onto an embodiment of a transducer and a corresponding earpiece configured for receiving the transducer; 
         FIG. 7B  shows a somewhat schematic perspective view of the transducer shown in  FIG. 7A ; 
         FIG. 8A  shows a somewhat schematic view looking down onto an embodiment of a transducer and a corresponding earpiece configured for receiving the transducer; and 
         FIG. 8B  shows a somewhat schematic cross-sectional view taken along line B-B as shown in  FIG. 8A . 
     
    
    
     DETAILED DESCRIPTION 
     Various terms used herein are intended to have particular meanings. Some of these terms are defined below for the purpose of clarity. The definitions given below are meant to cover all forms of the words being defined (e.g., singular, plural, present tense, past tense). If the definition of any term below diverges from the commonly understood and/or dictionary definition of such term, the definitions below control. 
     Turning now to the drawings wherein like reference characters indicate like or similar parts throughout,  FIGS. 1 ,  2 , and  5 - 8  illustrate different aspects of a hearing aid apparatus  10 . The hearing aid apparatus  10  operates based on the steps of receiving input information in the form of sound waves or other signals (e.g., direct electrical signals) using, for example, a microphone  12 , transforming the input information into transfer information (e.g., amplifying, filtering, or otherwise changing the input information) using, for example, an amplifier  14 , generating vibrational energy based on the transfer information using, for example, a vibrator or other means for initiating vibration based on an electrical signal  16 , and conducting the vibrational energy through an earpiece shell  36  to a user&#39;s mastoid bone for interpretation by a user&#39;s brain.  FIG. 2  shows a functional block diagram illustrating how various parts of a typical ITE bone conduction hearing aid are interconnected in order to carry out these and other steps. Electrical power is provided by a power source  20  which is typically in the form of a battery. An access port  21  is preferably provided to gain access to and replace the power source if necessary. The level of amplification can be adjusted with volume control  22  which controls the gain of the amplifier  14 , and an optional feedback control  24  may be provided for adjusting electronic parameters to reduce or eliminate feedback from the vibrator or other means for initiating vibration  16  or from other components. These and other prior art features are discussed, for example, in U.S. Pat. No. 7,302,071 to Schumaier which is incorporated herein by reference in its entirety. 
     The components that generate vibrations collectively form at least part of what is often referred to as a transducer or vibrator  26  which typically includes, for example, means for initiating vibration  16  and a spring member  18 . The transducer  26  also preferably includes a housing  28 . The housing  28  is preferably removably fixed within an in the ear (ITE) portion  30  of the hearing aid. Prior art versions of transducers include, for example, the VKH2 produced by BHM-Tech Produktionsgesellschaft mbH of Grafenschachen, Austria, or, for example, a Radio Ear B-71 vibrator or Starkey BC1 vibrator available from Starkey Laboratories, Inc., of Eden Prairie, Minn. Other components such as, for example, the microphone  12  and the amplifier  14  are housed in a behind the ear (BTE) component  32 . The ITE component  30  and the BTE component  32  are connected directly by, for example, a conductive wire  34 , or, alternatively, by indirect electromagnetic (e.g., infrared or other waveforms) communication technology. The ITE component  30 , also referred to as the “earpiece,” includes an earpiece shell  36  having a cavity  38  defining an inner surface  40  of the earpiece shell  36 . The transducer  26  is preferably located within the cavity  38 . 
     In prior art earpieces  44  such as shown in  FIGS. 3 and 4 , a transducer  41  is attached to the earpiece shell  36  by, for example, a screw  46  which engages a mounting plate  42 . One of the drawbacks of the prior art earpiece  44  shown in  FIG. 3  is that the mounting plate  42  and associated hardware (e.g., screw  46  and alignment pins  45 ) take up a significant amount of volume in the cavity  38  of the earpiece shell  36 , thus limiting space for other important components and/or limiting the sizes of earpiece shells that can be used with the transducer  41 . Also, the size of the mounting plate  42  is necessarily a function of the size of the fasteners used to fasten the mounting plate  42  to the earpiece shell  38 , which limits how small the mounting plate  42  can be in the earpiece  44  because a minimal size is necessary to accommodate such fasteners. Also, removal and replacement of the transducer  41  is tedious because of difficulties in accessing the screw  46  through a small opening  47  in the earpiece shell  36 . 
       FIGS. 1 ,  2 , and  4 - 6  show an embodiment of the improved hearing aid apparatus  10  that does not suffer from the drawbacks associated with the earpiece  44  shown in  FIG. 3 . The transducer  26  is preferably located partially or completely within the cavity  38  and attached adjacent the inner surface  40  of the earpiece shell  36 . The transducer  26  further includes the spring member  18  attached adjacent the housing  28 , a weight  48  attached adjacent the spring member  18 , and the means for initiating vibration  16  disposed at least partially within the housing  28 . The earpiece  30  also preferably includes a cover plate  50  for covering an aperture  52  defined by the entrance to the cavity  38  of the earpiece shell  36 . The earpiece shell  36  is preferably made of one or more acrylate polymers or copolymers. Preferably, the transducer  26  is removably attachable adjacent the inner surface  40  of the earpiece shell  36  so that the same transducer  26  may be used with different earpiece shells. The housing  28  is the portion of the transducer  26  that is attached adjacent the inner surface  40  of the earpiece shell  36 , and such housing  28  is preferably press fit into position within the cavity  38  without using fasteners or other objects that unnecessarily take up space within the cavity  38  and require tedious assembly procedures. 
     In the embodiment shown in  FIGS. 5 and 6 , one or more interference members  54  (e.g., a ledge or other interrupting feature formed along the inner surface  40  of the earpiece  30 ) limit the depth to which the housing  28  may be pressed into the cavity  38 . In one embodiment shown in  FIGS. 7A and 7B , the inner surface  40  of the earpiece shell  36  includes a substantially planar first subsurface  56  for engagement adjacent a first portion  58  of an outer surface  60  of the housing  28 . In a related embodiment shown in  FIGS. 8A and 8B , the inner surface  40  of the earpiece shell  36  includes a substantially planar second subsurface  62  for engagement adjacent a second portion  64  of the outer surface of the housing  28 . Also, these respective surfaces may be angled as shown most clearly in  FIG. 8B  to facilitate press fitting of the transducer  26  within the earpiece shell  30 . Interference members  54 ′ are also shown in  FIGS. 8A and 8B . In other contemplated embodiments, for example, only the first subsurface  56  and the first portion  58  of the outer surface of the housing  28  could be angled to achieve the same wedging effect when a transducer is press fit into an earpiece shell. In embodiments with one or more pairs of engageable angled surfaces, one or more interference members  54  would not be necessary because of the created wedging effect. Nonetheless, one or more interference members  54  can be used to better ensure that a transducer is not forced into an earpiece beyond a desired maximum depth. 
     The earpiece shell  36  is preferably made of a vibrationally conductive material suitable for transferring vibration produced by the transducer  26  into the ear canal of a user and then to the user&#39;s mastoid bone. Suitable materials include hard plastic, hard Lucite and acrylic materials. In many such earpieces, the means for initiating vibration  16  of the transducer  26  preferably includes a coil  68 , a magnet  70 , and a magnetic plate  72  as shown in  FIG. 5 . In other embodiments, the means for initiating vibration comprises another type of electromagnetic transducer, a piezoelectric crystal transducer, a differential floating mass transducer, or other similar devices. Accordingly, one skilled in the art will appreciate that the invention is not limited to any particular device or structure for initiating vibration based on an electrical signal. 
     An example shown in  FIG. 6  illustrates the spring member  18 , preferably a two-section linear spring, wherein each section includes a first end  74  and a second end  76 . The first end  74  of each section of the spring member  18  is attached to the housing  28  using a screw  78 , and the second end  76  of each section is attached to the weight  48  adjacent a second location  80 . Unlike the embodiments shown in  FIGS. 3 and 4 , the weight  48  shown in  FIGS. 1 ,  2 , and  4 - 6  is free to move on the spring sections within the cavity  38  without touching the earpiece shell  36 . Also, the weight  48  can be much smaller than the mounting plate  42  used in the embodiments shown in  FIGS. 3 and 4  because there is no need to provide room for attaching fasteners to the weight  48  in the embodiment shown in  FIGS. 1 ,  2 , and  4 - 6 . The weight  48  has a known first mass M 1  such that the peak vibration frequency of the earpiece can be predicted or otherwise maintained within a specified range. The weight  48  may be constructed from any material or combination of materials that provide the desired mass. 
     The weight  48  and spring member  18  preferably may be removed by removing the screws  78 . In this manner, a second weight having a known second mass M 2  can be interchanged with the original weight, thereby providing the capability of altering the peak frequency of the earpiece  30  by substituting the original weight  48  having mass M 1  with a second weight having mass M 2 , wherein M 1  does not equal M 2 . Additionally or alternatively, the entire transducer  26  including the original weight  48  could be substituted with a second transducer including a second weight having mass M 2 , thereby accomplishing the same alteration in output peak frequency during use. This interchangeability provides one or more methods for altering the output frequency of a hearing aid apparatus including, for example, the steps of (i) removing a first object from an earpiece (e.g., the earpiece  30  shown in  FIG. 5 ) wherein the first object at least includes the original (or first) weight  48  having mass M 1 ; and (ii) adding a second object to the earpiece to replace the first object, wherein the second object at least includes the second weight having mass M 2 . In a related embodiment, the first object could include the first transducer  26  and first weight and the second object could include a second transducer and the second weight having mass M 2 . 
     The hearing aid apparatus  10  operates based on the steps of receiving input information in the form of sound waves or other signals (e.g., direct electrical signals), transforming the input information into transfer information (e.g., amplifying, filtering, or otherwise changing the input information), generating vibrational energy based on the transfer information, and conducting the vibrational energy through the housing  28 , and through the earpiece shell  36  to a user&#39;s skull for interpretation by a user&#39;s brain. Unlike the prior art structure shown in  FIGS. 3 and 4 , vibrational energy is not transferred through the spring member  18  to the mounting plate  42  (and associated fastener(s)) and then through the earpiece shell  36 . Rather, in the embodiments shown in  FIGS. 1 ,  2 , and  4 - 6 , vibrational energy is transferred directly through the housing  28  to the earpiece shell  36 , while the frequency remains a function of the mass of the weight  48  attached adjacent the spring member  18 . 
     The previously described embodiments of the present disclosure have many advantages, including increasing the number, types, and sizes of earpiece shells that can be used for ITE and other hearing aid applications. The embodiments described above also eliminate the need to attach a mounting plate to an earpiece shell, which, due to size constraints, can easily become dislodged or otherwise separated from an earpiece shell, thereby rendering prior art versions of such hearing aids virtually useless. Additionally, the weight used in various embodiments described above can have a mass much less than the prior art mounting plates, and less mass translates into higher peak frequency output by the disclosed embodiments. Higher peak frequency output is preferable to lower peak frequency, so this feature is an additional benefit to the disclosed embodiments. 
     The foregoing description of preferred embodiments of the present disclosure has been presented for purposes of illustration and description. The described preferred embodiments are not intended to be exhaustive or to limit the scope of the disclosure to the precise form(s) disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the disclosure and its practical application, and to thereby enable one of ordinary skill in the art to utilize the concepts revealed in the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. 
     Any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. §112, ¶6. In particular, the use of “step of” in the claims herein is not intended to invoke the provisions of 35 U.S.C. §112, ¶6.