Patent Publication Number: US-2002001391-A1

Title: Acoustic switch with electronic switching capability

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
     [0001] This application claims priority of U.S. Provisional Patent Application No. 60/189,954. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] The present invention relates to microphones for use in hearing aids. In particular, the present invention relates to microphone construction having a switching element capable of mechanically positioning the microphone into an omni-directional or directional mode while completing either a first electric circuit or a second electric circuit.  
       [0003] Hearing aids that have the capabilities of a directional microphone and an omni-directional microphone are advantageous to the user. In certain situations an omni-directional microphone is preferred to a directional microphone and vice versa. For example, in a reverberant environment or in an environment that has background noise, a directional microphone will improve speech intelligibility. Directional microphones are also preferred when the sound source is close to the hearing aid user. In addition, attenuation of sounds coming from the rear provide better listening comfort in a noisy environment. Likewise, in other environments, directionality may not be needed, and in fact, may be a detriment.  
       [0004] For purposes of this application, by directional microphone is meant a microphone having two physically separated acoustic ports which acoustically relate back to opposite sides of a microphone diaphragm. In contrast, an omni-directional microphone has only one acoustic port which acoustically relates to only one side of the microphone diaphragm.  
       [0005] In the past, two microphones have been included in hearing aids, one an omni-directional microphone and the other a directional microphone. The hearing aid user may switch electronically from one to the other. David Preves,  Directional Microphone Use in ITE Hearing Instruments , The Hearing Review, July 1997; Olson et al.,  Performance of SENSO C 9  Directional , Widexpress, July 1997. This type of hearing aid construction has the disadvantage of the cost of two microphones and the added space that two microphones require.  
       [0006] There have also been attempts to provide a hearing aid that permits the user to select between directional or omni-directional modes using one microphone. Such hearing aid constructions are described in the following patents:  
                                                   Inventor   U.S. Pat. No.                          Killion   3,835,263           Johanson et al.   3,836,732           Johanson et al.   3,909,556           Cole   4,051,330           Berland   4,142,072                      
 
       [0007] However, the hearing aid constructions in the above mentioned patents are not conducive to a miniature-in-the-ear type of hearing aid construction since the switching mechanisms and the acoustic channels take up too much space.  
       [0008] Additionally, at times the user of the hearing aid may require more features than choosing between omni-directional and directional modes, such as an equalization circuit or a sound attenuation circuit. Previously, separate switches were required to provide the mechanical switching from an omni-directional mode to a directional mode and also to switch electric circuits on and off. The separate switches caused the hearing aids to become larger and as such are not conducive to miniature-in-the-ear hearing aid constructions.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009] The present invention includes a microphone constriction for use in a hearing aid having a housing with first and second acoustic passages in communication with a microphone retaining chamber and acoustic openings in an exterior surface. A microphone, disposed within the microphone retaining chamber, has a first acoustic port in an acoustic relationship with the first acoustic passage and a second acoustic port in an acoustic relationship with the second acoustic passage. A first and second set of electrical leads are disposed within the housing. A switching mechanism is secured to the housing and is positionable between a first position and a second position. In the first position, the first and second acoustic passages are in an acoustic receptive state and a first electric circuit is completed by connecting the first set of leads with a first connecting element. In the second position, either the first or the second acoustic passage is in an acoustic receptive state while the other acoustic passage is in an acoustic unreceptive state and a second electric circuit is completed by connecting the second set of leads with a second connecting element. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010]FIG. 1 is an exploded perspective view of the hearing aid construction of the present invention.  
     [0011]FIG. 2 is a perspective view of the housing of the hearing aid as viewed from above the housing.  
     [0012]FIG. 3 is a sectional view of a connector positioned adjacent to a set of leads which completes an electric circuit.  
     [0013]FIG. 4 is a sectional view of the hearing aid construction in a directional mode.  
     [0014]FIG. 5 is a schematic view of the switching mechanism in a first position.  
     [0015]FIG. 6 is a schematic view of the switching mechanism in a second position.  
     [0016]FIG. 7 is an exploded perspective view of a first alternative embodiment of the hearing aid construction of the present invention.  
     [0017]FIG. 8 is perspective view of the housing of the first alternative embodiment of the hearing aid construction of the present invention  
     [0018]FIG. 9 is a perspective view of a second alternative embodiment of the hearing aid construction of the present invention.  
     [0019]FIG. 10 is a partially exploded view of the second alternative embodiment of the hearing aid construction of the present invention as viewed from above.  
     [0020]FIG. 11 is an exploded perspective view of the second alternative embodiment of the hearing aid construction of the present invention as viewed from beneath the construction.  
     [0021]FIG. 12 is a top view of the second alternative embodiment of the hearing aid construction of the present invention.  
     [0022]FIG. 13 is a sectional view of the second alternative embodiment of the present invention along the section line  1 - 1  in FIG. 12.  
     [0023]FIG. 14 is a sectional view of the second alternative embodiment of the present invention along the section line  2 - 2  in FIG. 12.  
     [0024]FIG. 15 is a side view of the second alternative embodiment of the present invention.  
     [0025]FIG. 16 is a partial sectional view of the second alternative embodiment of the present invention along the section line  3 - 3  in FIG. 15. 
    
    
     DETAILED DESCRIPTION  
     [0026] Referring to FIG. 1 the hearing aid construction of the present invention is generally indicated at  10 . As illustrated in FIG. 1, the housing  12  preferably includes matching and substantially identical housing halves  14  and  16 . The housing halves  14  and  16  are identical except for the location of a first lead retaining indention  52  and a second retaining indention  54  which are not symmetrically located within the first and second housing halves  14  and  16  as best illustrated in FIG. 2.  
     [0027] A switching mechanism  15  is attached to a second end  50  of the housing  12 . The switching mechanism  15  includes both mechanical switching capabilities and electrical switching capabilities thereby allowing a single switching mechanism to perform multiple functions. In a hearing aid construction, it is advantageous to reduce the size of equipment, and reducing the number of switches allows the size of the hearing aid construction to be reduced. The switching mechanism  15  is positioned into a first position where a microphone  26  is in a directional mode and a first electric circuit  60  is completed while a second electric circuit is broken as illustrated in FIG. 5. The switching mechanism  15  is rotated into a second position wherein the microphone  26  is in an omni-directional mode and the second circuit is completed while the first electric circuit is broken as illustrated in FIG. 6.  
     [0028] Referring to FIG. 4, each housing half  14  and  16  includes an acoustic passage  18  and  20 . Each acoustic passage  18  and  20  extends from an exterior opening  19  and  21  to an interior opening  24  and  25  within a microphone retaining chamber  28  of the housing halves  14  and  16 , all respectively.  
     [0029] The directional microphone  26  is positioned within the microphone retaining chamber  28  that is formed by the housing halves  14  and  16 . The directional microphone  26  is of standard construction having a first acoustic port  30  and a second acoustic port  32  disposed on opposite sides of a diaphragm (not shown). The acoustic ports  30  and  32  are positioned to be in an acoustic relationship with the acoustic passages  18  and  20  through openings  24  and  25  of the housing halves  14  and  16 , all respectively, when the microphone  26  is positioned within the chamber  28 . The housing halves  14  and  16  may be joined together by any suitable method such as adhesive, ultrasonic welding or a snap fit of a pin in the first housing half being inserted into a mating hole in the second housing half and a pin in the second housing half being inserted into a mating hole in the first housing half.  
     [0030] Acoustic dampers  38  and  40  are positioned within recesses  17  and  23  proximate the openings  24  and  25 , respectively, such that the acoustic dampers  38  and  40  completely cover the openings  24  and  25  without extending beyond a flat surface  29  and  27 , all respectively, of the microphone retaining chamber  28 . Alternatively, the dampers  38  and  40  can be positioned inside the microphone  26  or at the exterior openings  19  and  21  of the acoustic passages  18  and  20 .  
     [0031] Damper seals  42  and  44  are disposed between the acoustic dampers  38  and  40  and the acoustic ports  30  and  32 , as best illustrated in FIG. 4. Each damper seal  42  and  44  is positioned adjacent to and substantially covers the surface  29  and  27 , respectfully, of the microphone retaining chamber  28 . With the damper seals  42  and  44  positioned adjacent to the surfaces  29  and  27  of the microphone retaining chamber  28 , an aperture  46  and  48  within the damper seals  42  or  44  is disposed about the interior acoustic openings  24  and  25 , respectively. When the housing halves  24  and  16  are joined together, the damper seals  42  and  44  form a seal between the housing  12  and the microphone  26 , while maintaining an acoustic relationship between the acoustic passages  18  and  20  and the acoustic ports  30  and  32  of the microphone  26 .  
     [0032] The damper seals  42  and  44  are made of a compressable polymer such as a natural or synthetic rubber and are necessary to provide a tight acoustic seal. The damper seals  42  and  44  eliminate any leakage due to variation in construction of the housing halves  14  and  16  and the microphone  26  and dimensional variations that may result from snapping together the housing halves  14  and  16 . The damper seals  42  and  44  along with the acoustic passages  18  and  20  being part of the housing  12  provide a very efficient acoustic path with virtually no leakage. The damper seals  42  and  44  provide a better acoustic seal than a standard O-ring seal because the damper seals  42  and  44  have more contact area between the housing  12  and the microphone  26  and thereby prevent sound from escaping from a gap between the housing  12  and the microphone  26 .  
     [0033] Referring to FIG. 2, first tabs  57  and  61  and second tabs  64  and  65  extend from each of the interior surfaces  35  proximate a second end  50  of the housing halves  14  and  16 . The first tabs  57  and  61  and the second tabs  64  and  65  are located proximate an outer edge  56  of the housing  12 . Substantially centrally located along the interior surface  35  and extending from the second end  50  are first and second semicircular center portions  66  and  67 , each having a groove  68  and  69  formed therein. When the housing halves  14  and  16  are joined such that the interior surfaces  35  are adjacent, the first tabs  57  and  61  cooperate to form a first stop  55 . Similarly, the second tabs  64  and  65  cooperate to form a second stop  59 . The semicircular portions  66  cooperate to form a member  72  having a cylindrical outer surface and an aperture  74  substantially centrally located within the cylindrical member  72 . It will be appreciated that the exterior openings  19  and  21  of the acoustic passages  18  and  20  are equidistant from the cylindrical member  76  which becomes important when switching from an omni-directional to a directional mode of operation.  
     [0034] Because the damper seals  42  and  44  are compressed when the housing halves  14  and  16  are snap fit together, the damper seals  42  and  44  urge the housing halves  14  and  16  apart. If the housing halves  14  and  16  slightly separate, the acoustic seal between the microphone  26  and the surface of the microphone retaining chamber  28  will be compromised making the hearing aid  10  less effective.  
     [0035] Referring to FIGS. 1 and 4, a first retaining ring  80  is positioned about a shoulder  82  proximate a first end  55  of the housing  12  thereby preventing the housing halves  14  and  16  proximate the first end  55  from separating. Referring to FIG. 4, a second retaining ring  81  is positioned about the cylindrical member  76  proximate the second end  50 , thereby preventing the housing halves  14  and  16  proximate the second end  50  from separating. With the first and second retaining rings  80  and  84  positioned about the housing  12  proximate the first and second ends  55  and  50 , the housing halves  14  and  16  are secured into a position thereby ensuring an acoustic seal between the housing  12  and the microphone  26 .  
     [0036] Referring to FIGS. 1 and 2, a first set of electrical leads  90  are attached to an exterior side surface of the first housing half  14 . Preferably the first set of leads  90  are retained within a first molding  94  which cooperates with the first lead retaining indention  52  within the exterior surface having a complimentary configuration to the first molding  94  such that the first molding  94  is secured to the first housing half  14 . The first set of leads  90  within the first molding  94  are located proximate the acoustic opening  19 . The first set of leads  90  can be attached to any electrical circuit which may be helpful to the user such as an equalizer, an electric filter to reduce background noise or an attenuation circuit. This list of circuits is by way of example and is in no way meant to be limiting. Preferably the first set of leads  90  and the molding  94  are a simple pole switch.  
     [0037] Attached to the exterior surface of the second housing half  16  is a second set of electrical leads  92 . The second set of leads  92  are contained within a second molding  96  having the same configuration as the first molding  94  containing the first set of leads  90 . The second housing half  16  includes a second lead retaining indention  54  within the exterior surface of the housing half  16  wherein the second lead retaining indention  54  has a complimentary configuration to the second molding  96  such that the second molding  96  is secured to the second housing half  16 . The second set of leads  92  are located proximate the second acoustic opening  21  the same distance away from the second acoustic opening  21  as the first set of leads  90  are located from the first acoustic opening  19 . The first and second sets of leads  90  and  92  are offset from the center of the housing  12  and cannot be connected by a line passing through the center of the housing  12  as best illustrated in FIG. 2.  
     [0038] Referring to FIG. 1, the switching mechanism  15  preferably has a circular perimeter corresponding to the general circumference and diameter of the housing  12  and is preferably rotatably attached to the housing  12 . The switching mechanism  15  includes acoustic switching ports  54 ,  56  and  58 , and a port  59  plugged with an acoustic port seal  60 . Attached to a second surface of the switching mechanism  15  are a plurality of gripping members  47  which allow the user to grip and manipulate the switching mechanism  15  as illustrated in FIGS. 1 and 4.  
     [0039] A first bore  102  is disposed between the acoustic ports  54  and  58 . A first compressive element  104  is disposed within the first bore  102 . A first connecting element  106  is position upon the first compressive element  104  such that the first connecting element  106  is partially disposed within the first bore  102  and partially extending therefrom. The compressive element  104  is preferably a compressive foam or a spring. The first connecting element  106  is preferably a ball or sphere constructed of an electrically conductive material such as copper or silver.  
     [0040] A second bore  108  is disposed between the acoustic ports  56  and  59 . A second compressive element  110  is disposed within the second bore  108 . A second connecting element  112  is positioned upon the second compressive element  110  such that the second connecting element  112  is partially disposed within the second bore  108  and partially extends therefrom. The compressive element  110  is preferably a compressive foam or a spring. The second connecting element  112  is preferably a ball or sphere constructed of an electrically conductive material such as copper or silver. The first connecting element  106  and the second connecting element  112  are positioned opposite each other such that a line passing through a center of the switching mechanism  15  intersects the connecting elements  106  and  112 .  
     [0041] A first indention  80  and a second indention  82  are disposed within a first surface  51  of the switching mechanism  15  where the second indention  82  is opposite the first indention  80 . The first and second indentions  80  and  82  have substantially similar geometries wherein each indention has arcuate first surfaces  84  and  86  and second surfaces  88  and  90 , respectively, wherein the first arcuate surfaces  84  and  86  are longer than the second arcuate surfaces  88  and  90 . The first and second arcuate surfaces  84 ,  86 ,  88 ,  90  are connected by side surfaces wherein radial lines define first side surfaces  92  and  94  and second side surfaces  96  and  98 .  
     [0042] Substantially centrally located within the switching mechanism  15  is a through hole  114 . A shoulder  116  centrally located and extending from the first surface  57  accommodates the second retaining ring  81 . A diameter of the through hole  114  at a second surface  53  accommodates the cylindrical member  72 .  
     [0043] The switching mechanism  15  is positioned about the housing  12  such that the cylindrical member  72  is substantially even with the second surface  53  of the switching mechanism  15 . Additionally, the first stop  55  is positioned within the first indention  80  and the second stop  59  is positioned within the second indention  82 . A pin  120  secures the switching mechanism  15  to the housing  12  by engaging the aperture  74  within the cylindrical member  72 . A plurality of ridges  122  extending from the shaft of a pin  120  engage the aperture  74  which secures the pin  120  within the aperture  74 . A head  124  of the pin  120  has a diameter greater than the diameter of the through hole  114  within the second surface  53  of the switching mechanism  15 . The head  124  prevents the switching mechanism  15  from detaching from the housing  12 , thereby rotatably securing the switching mechanism  15  to the housing  12 . The first and second compressible elements  104  and  110  are compressed such that the first and second connecting elements  106  and  112  are disposed within the first and second bores  102  and  108  thereby positioning the first surface  51  of the switching mechanism  15  adjacent to the housing  12  when the switching mechanism  15  is rotatably secured to the housing  12 .  
     [0044] In operation, the hearing aid  10  is positioned into a first position corresponding to a directional mode and also connecting the first set of leads  90  as illustrated in FIG. 5. The switching mechanism  15  is manipulated into the first position by rotating the switching mechanism  15  until the first stop  55  contacts the first side surface  92  of the first indention  80  and at substantially the same time, the second stop  59  contacts the first side surface  94  of the second indention  82 . With the first and second stops  62  and  59  contacting the first side surfaces  92  and  94  of the first and second indentions  80  and  82 , the first acoustic port  54  aligns with the acoustic passage  18  in the first housing half  14  and the second acoustic port  56  aligns with the acoustic passage  20  in the second housing half  16 . With the acoustic passages  18  and  20  able to pass sound therethrough, the first and second acoustic ports  30  and  32  of the microphone  26  are in an acoustically receptive state thereby positioning the hearing aid  10  into a directional mode.  
     [0045] Besides placing the microphone  26  into a directional mode, the first connector  106  connects the first set of leads  90  and thereby completes a first electrical circuit  60  allowing the hearing aid construction  10  to perform an additional operation. Referring to FIG. 3 the first electric circuit  60  is completed by a surface of the connector  106  being forced into contact with the ends of the first set of leads  90 , the force being applied to the connector  106  by the compressible element  104 . Referring to FIG. 5, the second connector  112  is a distance from the second set of leads  92  and thereby prevents the hearing aid construction  10  from performing an operation connected to the second set of leads  92 .  
     [0046] The user of the hearing aid construction  10  can place the hearing aid construction  10  into a second position or an omni-directional mode and also complete the second electric circuit  62  as illustrated in FIG. 6. To manipulate the hearing aid construction  10  into the second position, the switching mechanism  15  is rotated until the first stop  55  contacts the second side surface  96  of the first indention  80 , and the second stop  59  contacts the second side surface  98  of the second indention  82 . With the first and second stops  62  and  59  contacting the second side surfaces  96  and  98  of the first and second indentions  80  and  82 , the third acoustic port  58  is aligned with the acoustic passage  18  in the first housing half  14 . The acoustic passage  20  in the second housing half  16  is sealed off by the acoustic port seal  60  within the port  59 . With the acoustic passage  20  in the second housing half  16  sealed, the acoustic port  32  in the microphone  26  which is in communication with the acoustic passage  20  in the second housing half  16  is in an acoustically unreceptive state.  
     [0047] Besides placing the microphone  26  in an omni-directional mode, the second connecting element  112  connects the second set of leads  92  and thereby completes a second electrical circuit  62  allowing the hearing aid construction  10  to perform a function associated with the second electrical circuit  62 . Additionally, the first connector  106  is a distance from the first set of leads  90  and thereby prevents the hearing aid from performing the operation associated with the first electrical circuit  60 .  
     [0048] A first alternative embodiment  210  of the present invention is illustrated in FIGS. 7 and 8. The hearing aid construction  210  is similar to the embodiment  10  and operates in the same manner. Components within the alternative embodiment  210  which are the same as the components in the embodiment  10  will be given the same reference numbers.  
     [0049] The differences between the embodiment  210  and the embodiment  10  include securing the first and second sets of leads  290  and  292  to an external surface of the housing  212  at the mating surfaces  235  of the housing halves  214  and  216  when the housing halves  214  and  216  are joined together. The first and second sets of leads  290  and  292  are opposite or 180 degrees away from each other. Additionally, the first and second leads  290  and  294  extend beyond a surface  250  of the housing  212 .  
     [0050] The connectors  206  and  212  are secured within the first and second indentions  80  and  82  adjacent to a first arcuate surface  84  and  86 , respectively. The connectors  206  and  212  are constructed of a flat metal material that conforms to the first arcuate surfaces  84  and  86 . The first connector  206  includes a first contact portion  207  positioned away from the first arcuate surface  84  proximate a first surface  92  of the indention  80 . The second connector  212  includes a second contact portion  213  positioned away from the first arcuate surface  86  proximate the second wall  98  of the indention  82 . The distance between the leads  290  and  292  must be narrower than the width of the first and second stops  55  and  59  so that the leads  290  and  292  do not interfere with the switching mechanism  215  being positioned into either the first or second position.  
     [0051] The operation of the embodiment  210  is similar to the operation of the embodiment  10 . The embodiment  210  is placed into a first position when the first surfaces  92  and  94  of the first and second indentions  80  and  82  are adjacent to the first and second stops  55  and  59 . With the first and second stops  55  and  59  contacting the first side surfaces  92  and  94  of the first and second indentions  80  and  82 , the first acoustic port  54  aligns with the acoustic passage  18  in the first housing half  214  and the second acoustic port  56  aligns with the acoustic passage  20  in the second housing half  216 . With the acoustic passages  18  and  20  able to pass sound therethrough, the first and second acoustic ports  30  and  32  of the microphone  26  are in an acoustically receptive state thereby positioning the hearing aid construction  210  into a directional mode.  
     [0052] Besides placing the microphone  26  into a directional mode, the first connector  206  connects the first set of leads  290  and thereby completes a first electrical circuit  60  allowing the hearing aid construction  210  to perform an additional operation. The first electric circuit  60  is completed by the first contact portion  207  of the first connector  206  contacting the first set of leads  290  which extend into the first indention  80  similar to the first stop  55 . Additionally, the second contact portion  213  of second connector  212  extending from the first arcuate surface  86  is proximate the second side wall  98  while the second set of leads  292  is proximate the first wall  94 , therefore the second electrical circuit  62  is broken which prevents the hearing aid construction  210  from performing an operation associated with the second electric circuit  62 .  
     [0053] The hearing aid construction  210  is manipulated into a second position by rotating the switching mechanism  15  about the pin  280  until the first stop  55  contacts the second side surface  92  of the first indention  80  and the second stop  59  contacts the second side surface  98  of the second indention  82 . With the first and second stops  55  and  59  contacting the second side surfaces  96  and  98  of the first and second indentions  80  and  82 , the third acoustic port  58  is aligned with the acoustic passage  18  in the first housing half  214 . The acoustic passage  20  in the second housing half  216  is acoustically blocked by the acoustic port seal  60  within the port  59 . With the acoustic passage  20  in the second housing half  216  sealed, the acoustic port  32  in the microphone  26  which is in communication with the acoustic passage  20  in the second housing half  216  is in an acoustically unreceptive state.  
     [0054] Besides placing the microphone into an omni-directional mode, the second connector  212  connects the second set of leads  292  and thereby completes the second electrical circuit  62  allowing the hearing aid construction  210  to perform an additional operation. The second electric circuit  62  is completed by the second contact portion  213  of the second connector  212  contacting the second set of leads  292  wherein the second set of leads  292  extend into the second indention  82  similar to the second stop  59 . Additionally, the first contact portion  207  of first connector  206  extending from the first arcuate surface  84  is proximate the first side surface  92  while the first set of leads  290  is proximate the second side surface  96 , thereby breaking the first electrical circuit  60  which prevents the hearing aid construction  210  from performing an operation associated with the first electric circuit  60 .  
     [0055] In a second alternative embodiment, the hearing aid construction  310  includes the switching mechanism  315  being sidably attached to the housing  312 . As illustrated in FIGS.  9 - 11 , the housing  312  contains a microphone  326  disposed between matching and identical housing halves  314  and  316 . A first set of leads  390  extend from a first side of the construction  310  and a second set of leads  394  extend from a second side of the construction  310 . The housing halves  314  and  316 , the first and second leads  390  and  394 , the microphone  326  and the switching mechanism  315  are retained into a position by a first retaining clip  350  and a second retaining clip  360 .  
     [0056] Referring to FIGS. 12 and 13, each housing half  314  and  316  includes an acoustic passage  318  and  320  extending from an exterior opening  319  and  321  to an interior opening  324  and  325  within a microphone retaining chamber  328  of the housing halves  314  and  316 , all respectively. The directional microphone  326  is positioned within the microphone retaining chamber  328  that is formed by the housing halves  314  and  316 . The directional microphone  326  is of standard construction having a first acoustic port  330  and a second acoustic port  332  disposed on opposite sides of a diaphragm (not shown). The acoustic ports  330  and  332  are positioned to be in an acoustic relationship with the acoustic passages  318  and  320  through the interior openings  324  and  325  of the housing halves  314  and  316 , all respectively, when the microphone  326  is positioned within the chamber  328 .  
     [0057] Referring to FIGS. 11 and 13, acoustic dampers  338  and  340  are positioned within recesses proximate the interior openings  324  and  325 , respectively, such that the acoustic dampers  338  and  340  completely cover the openings  324  and  325  without extending beyond a surface  329  and  327  of the microphone retaining chamber  328 . Alternatively, the dampers  338  and  340  can be positioned inside the microphone or at the exterior openings of the acoustic passages.  
     [0058] Damper seals  342  and  344  are disposed between the acoustic dampers  338  and  340  and the acoustic ports  330  and  332 . Each damper seal  342  and  344  is positioned adjacent to and substantially covers the surfaces  329  and  327  of the microphone retaining chamber  328 . With the damper seals  342  and  344  positioned adjacent to the surfaces  329  and  327  of the microphone retaining chamber  328 , an aperture within each damper seal  342  and  344  disposes about the interior acoustic opening  324  and  325  within each surface  329  and  327 , respectively. When the housing halves  314  and  316  are joined together, the damper seals  342  and  344  form a seal between the housing  312  and the microphone  326 , while maintaining an acoustic relationship between the acoustic passages  318  and  320  and the acoustic ports  330  and  332  of the microphone  326 .  
     [0059] The damper seals  342  and  344  are made of a compressable polymer such as a natural or synthetic rubber and are necessary to provide a tight acoustic seal. The damper seals  342  and  344  eliminate any leakage due to variation in construction of the housing halves  314  and  316  and the microphone  326  and dimensional variations that may result from clipping together the housing halves  314  and  316 . The damper seals  342  and  344  along with the acoustic passages  318  and  320  being part of the housing  312  provide a very efficient acoustic path with virtually no leakage. The damper seals  342  and  344  provide a better acoustic seal than a standard O-ring seal because the damper seals  342  and  344  have more contact area between the housing  312  and the microphone  326  and thereby prevent sound from escaping from a gap between the housing  312  and the microphone  326 .  
     [0060] Referring to FIG. 10, each housing half  314  and  316  includes a raised portion  370  and  372  substantially centrally located within a top surface  374  and  376  and extending along a length thereof. Within the raised portions  370  and  372  of each housing half  314  and  316  are the exterior openings  319  and  321  of the acoustic passages  318  and  320 . A first portion  378  and  380  extending from a first side of the raised portion  370  and  372  includes a first thin portion (not shown), proximate contacting ends  386  and  388  of the housing halves  314  and  316  positioned below the first set of leads  381 . Referring to FIG. 10, within the first side portions  378  and  380  are first grooves  381  and  392 , each extending from an end of the first thin portions (not shown) wherein the grooves  390  and  392  are proximate and parallel to the raised portions  370  and  372 , all respectively.  
     [0061] Second side portions  394  and  396  extend from second sides of the raised portions  370  and  372 . The second side portions  394  and  396  also include second thin portions  398  and  400  as illustrated in FIG. 11, proximate the contacting ends  386  and  388 , each having the same dimensions as the first thin portions (not shown) of the first side portions  378  and  380 . Referring back to FIG. 10, second grooves  402  and  404 , extending from an end of the second thin portions  398  and  400 , are proximate and parallel to the raised portions  370  and  372 , respectively.  
     [0062] The contacting ends  386  and  388  of the housing halves  314  and  316  are placed adjacent each other such that the raised portions  370  and  372  align to form one continuous raised portion  371  along the length of the housing  312 . The first side portions  378  and  380  align to form a first recess for retaining the first set of leads  390 . Similarly, the second side portions  394  and  396  align to form a second recess for retaining the second set of leads  394 . Additionally, the first grooves  390  and  392  and the second grooves  402  and  404  are aligned but separated by the first and second recesses, respectively.  
     [0063] Extending from second surfaces  410  and  412  of the top portion of the first and second housing halves  314  and  316  are first and second microphone retaining portions  414  and  416  as best illustrated in FIG. 11. The first and second acoustic passages  318  and  320  are within the first and second microphone retaining portions  414  and  416  wherein the interior openings  324  and  325  of the first and second acoustic passages  318  and  320  are located within the first and second flat surfaces  329  and  327  of the first and second microphone retaining portions  414  and  416 , respectively. Extending outwardly from first side surfaces  420  and  422  and second side surfaces  424  and  426  of the microphone retaining portions  414  and  416  are first tabs  428  and  430  and second tabs  432  and  434  wherein a surface of the first tabs  428  and  430  and the second tabs  432  and  434  are substantially even with the flat surfaces  429  and  427 .  
     [0064] The first set of leads  390  are positioned within the first recess created by the first side portions  378  and  380  of the first and second housing halves  314  and  316 . The first set of leads  390  proximate a first end are retained within a first molding  391 . The molding  391  is constructed of a nonconductive material so that the molding  391  does not connect the first set of leads  390  and thereby completing a first electric circuit. The molding  391  is of a configuration such that the molding  391  is positioned and retained within the first recess and is supported by the first thin portions (not shown). Extending inwardly from the molding  391  are ends  393  of the first set of leads  390 . The ends  393  of the first set of leads  390  are adjacent to a side of the raised portion  371 .  
     [0065] Similarly, a second set of leads  394  are positioned within a second recess and supported by the second thin portions  398  and  400  within the second side portions  394  and  396  of the first and second housing halves  314  and  316 . The second set of leads  394 , proximate a first end  397 , are retained within a second molding  395 . The molding  395  is constructed of a nonconductive material such the molding  395  does not connect the second set of leads  394  and thereby complete the second circuit. The molding  395  is of a configuration such that the molding  395  is positioned and retained within the second recess created by the thin portions  398  and  400 . Extending inwardly from the molding  395  are the first set of lead ends  397  of the second set of leads  394 . The ends  397  of the second set of leads  394  are positioned adjacent to a second side surface of the raised portion  371 .  
     [0066] The switching mechanism  315 , having a width substantially the same as the width of the housing  312 , slidably engages the housing  312 . Referring to FIG. 11, the switching mechanism  315  includes a first surface  440  which is complimentary to the top surfaces  374  and  376  of the housing  312 . The switching mechanism  315  includes a recess  442  which disposes about the raised portion  371  of the housing  312 . Within the first surface  440  is a first channel  444  and a second channel  446  which align with the first grooves  381  and  392  and the second grooves  402  and  404  within the housing, respectively. Proximate a first end  460  of the switching mechanism  315  is a curved indention  462  and proximate a second end  464  of the switching mechanism  315  is a recess  466  having an acoustic port seal  468  disposed therein.  
     [0067] The first channel  444  accommodates a first connector  448  wherein the first connector  448  is made of an electrically conductive material. Proximate a first end  449  of the connector  448  is a curved portion  450  extending beyond the first surface  440  of the switching mechanism  315 . With the switching mechanism  315  engaging the housing  312 , the curved portion  450  extends into the first set of grooves  381  and  392  in the housing  312  a distance which allows the curved portion  450  to contact the first set of leads  390  between the molding  391  and the raised portion  371  when the curved portion  450  is positioned between the first set of leads  390 , thereby completing a first electric circuit as illustrated in FIG. 16.  
     [0068] The second channel  446  accommodates a second connector  452  wherein the second connector  452  is of the same configuration as the first connector  448  and is made of an electrically conductive material. The second connector  452  is positioned within the second channel  446  opposite the position of the first connector  448  in the first channel  444 . Proximate a first end  456  of the second connector  452  is a curved portion  454  extending beyond the first surface  440  of the switching mechanism  315 . With the switching mechanism  315  engaging the housing  312 , the curved portion  454  extends into the second set of grooves  402  and  404  in the housing  312  a distance which allows the curved portion  454  to contact the second set of leads  394  when the curved portion  454  is positioned between the second set of leads  394 , thereby completing a second electric circuit.  
     [0069] The configuration of the first and second connectors  448  and  452  within the switching mechanism  315  and the position of the first and second sets of leads  390  and  394  within the housing  312  prevent the first and second electric circuits from being completed at the same time. As illustrated in FIG. 14, when the first curved portion  450  contacts the first set of leads  390  and thereby completing the first electric circuit, the second curved portion  454  is a distance from the second set of leads  394 , thereby breaking the second electric circuit. Similarly, when the second curved portion  454  contacts the second set of leads  394 , thereby completing the second electric circuit, the first curved portion  450  is a distance from the first set of leads  390 , thereby breaking the first electric circuit.  
     [0070] With the microphone  326 , the first set of leads  390  and the second set of leads  394  positioned within the housing  312  and the switching mechanism  315  positioned on the housing  312 , the construction  310  is fixed into a position with the first and second clips  350  and  360  being of identical configuration. The first and second clips  350  and  360  include main portions  352  and  362  each having first side tabs  354  and  364  proximate a first end and second side tabs  356  and  366  proximate the second end and switch retaining members  358  and  368  extending from a top surface.  
     [0071] Referring to FIG. 14, the switching mechanism  315  includes a first groove  470  within a first side surface  472  and a second groove  474  within a second side surface  476 . The first side surface  472  of the switching mechanism  315  is retained on the housing  312  by the switch retaining member  358  extending inwardly from the first clip  350 . The second side surface  476  is retained on the housing  312  by the second switch retaining member  368 . The first and second moldings  391  and  395  are retained in position by an extension  482  and  484  disposed above the moldings wherein the extensions  482  and  484  define a bottom surface of the first and second grooves  472  and  474 .  
     [0072] Referring to FIGS.  10 , The first clip  350  includes first apertures  357  and  359  within the main portion  352  which accommodate the first set of leads  390  such that the first set of leads  390  pass therethrough. The first clip  350  is preferably constructed from a nonconductive material thereby preventing the first clip  350  from completing the first electric circuit.  
     [0073] The switch retaining member  358  extends from the top end proximate the first and second apertures  357  and  359 . Referring to FIG. 14, the switch retaining member  358  extends into a first groove  470  within a first side  472  of the switching mechanism  315 , thereby securing the first side  472  of the switching member  315  to the housing  312 . Additionally, the switch retaining member  358  covers a side of the first recess and thereby prevents the first set of leads  390  and the molding  391  from being displaced from the side of the housing.  
     [0074] With the first set of leads  390  positioned through the first and second apertures  357  and  359  and the switch retaining mechanism  358  disposed within the first groove  470  in the first side surface  472  of the switching mechanism  315 , the main portion  352  is rotated toward the microphone  326 . As the main portion  352  is rotated toward the microphone  326 , the first and second side tabs  354  and  356  engage the first tabs  428  and  430  extending from the first and second housing halves  314  and  316 . respectively. The engagement of the first and second side tabs  354  and  356  of the first clip  350  with the first tabs  428  and  430  of the housing halves  314  and  316  urges the first and second housing halves  314  and  316  together and retains the microphone  326  between the housing halves  314  and  316 .  
     [0075] The first clip  350  is positioned onto the housing  312  until an edge of the first and second side tabs  354  and  356  are adjacent to flat surfaces  420  and  422  of the microphone retaining portions  414  and  416 , respectively. When the edges of the first and second side tabs  354  and  356  are adjacent to the flat surfaces  420  and  422  of the microphone retaining portions  414  and  416 , the first clip  350  is securely attached to the housing  312  and retains a first side of the housing halves  314  and  316  and the microphone  326  into a selected position.  
     [0076] The second clip  360  is positioned onto the construction  310  in an identical fashion as the first clip  350 . The second clip  360  has an identical construction as the first clip  350 . The second clip includes first and second apertures  367  and  369  within the main portion  362  which accommodate the second set of leads  394  such that the second set of leads  394  pass therethrough. The second clip  360  is preferably constructed from a nonconductive material thereby preventing the second clip  360  from completing the second electric circuit.  
     [0077] The switch retaining member  368  extends from the top end proximate the first and second apertures  367  and  369 . Referring to FIG. 14, the switch retaining member  368  extends into the second groove  474  within the second side  476  of the switching member  315 , thereby securing the second side  476  of the switching member  315  to the housing  312 .  
     [0078] With the second set of leads  394  positioned through the first and second apertures  367  and  369  and the switch retaining member  368  disposed within the second groove  474  in the second side surface  476  of the switching member  315 , the main portion  362  of the second clip  360  is rotated toward the microphone  326 . As the main portion  362  is rotated toward the microphone  326 , the first and second side tabs  364  and  366  engage the second tabs  432  and  434  extending from the first and second housing halves  314  and  316 . The engagement of the first and second side tabs  364  and  366  of the second clip  360  with the second tabs  432  and  434  of the housing halves  314  and  316  urges the first and second housing halves  314  and  316  together thereby retaining the microphone  326  between the housing halves  314  and  316 .  
     [0079] The second clip  360  is positioned onto the housing  312  until an edge of the first and second side tabs  364  and  366  are adjacent to second flat surfaces  424  and  426  of the microphone retaining portions  414  and  416 . When the edges of the first and second side tabs  364  and  366  are adjacent to the second flat surfaces  424  and  426  of the microphone retaining portions  414  and  416 , the second clip  360  is securely attached to the housing  312  and retains a second side of the housing halves  314  and  316  and the microphone  326  into a selected position.  
     [0080] With the switching mechanism  315  slidably retained to the housing  12 , the hearing aid construction  310  is positioned into a first position when a first end  500  of the first and second grooves  470  and  472  are adjacent to the switch retaining members  358  and  368 . With the switching mechanism  315  in the first position, the second end  470  of the switching mechanism  315  is positioned between the first acoustic port  319  and the second acoustic port  321  leaving the first acoustic passage  318  open. With the first acoustic port  319  open, the first acoustic port  330  of the microphone  326  is in an acoustically receptive state. Additionally, the curved indention  462  is disposed about the second acoustic opening  321 . With the second acoustic opening  321  exposed, the second acoustic port  332  in the microphone  326  is in an acoustic receptive state. Therefore, the microphone  326  is in a directional mode when the switching mechanism  315  is positioned into the first position. Additionally, besides positioning the microphone  326  into a directional mode, the curved portion  454  of the second connector  452  connects the second set of leads  394  and thereby completes the second circuit.  
     [0081] The hearing aid construction  310  is positioned into a second position by applying a force to a gripping member  475 , an integral component of the switching mechanism  315 , and sliding the switching member  315  about the housing  312  such that the second ends  502  of the grooves  472  and  474  is adjacent to the switch retaining members  358  and  368 . With the hearing aid construction  310  in the second position, the second end  460  is between the first acoustic opening  319  and the second acoustic opening  321  and therefore the switching mechanism  315  does not interfere with the second acoustic opening  321  and therefore places the second acoustic port  332  in the microphone  326  into an acoustic receptive state. The first acoustic opening  319  is sealed by the acoustic port seal  468  disposed within the recess  466  in the switching mechanism  315  and therefore places the first acoustic port  330  into an acoustic nonreceptive state. Therefore, the microphone  326  is in an omni-directional mode when the switching mechanism  315  is in the second position.  
     [0082] Additionally when the switching mechanism  315  is in the second position, the curved portion  450  of the first connector  448  is positioned between the first set of leads  390 , thereby completing the first electric circuit. The curved portion  454  of the second connector  452  is positioned away from the second set of leads  394  and thereby breaks the second circuit. Therefore when the switching mechanism  315  is in the second position, the microphone  326  is in an omni-directional mode, the first electric circuit is complete and the second electric circuit is broken.  
     [0083] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.