Abstract:
An acoustic microphone configuration includes first and second acoustic microphones, each microphone having a port, the ports being spaced apart from each other a selected distance and being disposed along substantially the same plane.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]    Applicant claims the priority date of U.S. Provisional Application 60/239,055, filed Oct. 10, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to hearing aids, and in particular, it relates to the use of multiple microphones and a positioning of such microphones.  
           [0003]    Gennum Corporation of Canada markets a directional hearing system sold under the trademark FrontWave™ that utilizes two omni-directional microphones that are spaced between 6 to 13 mm. The FrontWave™ system has limited directivity performance due to the limited physical microphone port spacing. The FrontWave™ system can be programmed to vary the polar response from hypercardiod, supercardiod and cardiod with limited hearing benefits imposed mainly by the physical port spacing. The directivity pattern generated by the two microphones is a function of the ratio of the internal electronic delay between the ports.  
           [0004]    Other arrangements include microphone arrays or multiple microphones that are positioned on eyeglass frames and the head, or on a body worn vest to improve the physical spacing between the microphones. However, these systems have cosmetic and conveniency limitations for the user.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    The present invention includes an arrangement for positioning miniature acoustic microphones wherein the ports of each microphone are positioned along the same plane and are spaced from each a selected distance. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a perspective view of the present invention.  
         [0007]    [0007]FIG. 2 is a perspective view of an in-the-ear configuration of the present invention.  
         [0008]    [0008]FIG. 3 is a perspective view of a behind-the-ear and in-the-ear configuration of the present invention.  
         [0009]    [0009]FIG. 4 is a plan view of the present invention.  
         [0010]    [0010]FIG. 5 is a perspective view of the present invention.  
         [0011]    [0011]FIG. 6 is a front view of the present invention.  
         [0012]    [0012]FIG. 7 is an exploded perspective view of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0013]    The present invention is generally indicated by  10  and  12  in FIG. 1. In-the-ear/in-the-canal hearing aids  10  and  12 , each have two unidirectional microphones  14  and  16 . The one unidirectional microphone  14  is located on a main body  18  of the hearing aid which is situated in the ear, as illustrated in FIG. 2. The other unidirectional microphone  16  is located on a boom that extends from the main body  18  and is disposed along the outer ear  22  above the lobe  24  at a lower portion of the helix  26 . Like reference characters will be used to indicate like elements throughout the drawings.  
         [0014]    The ports  17  and  19  of the two unidirectional microphones are spaced apart to provide enhanced beam forming capabilities which result from increasing the spacing between the microphone ports. An example of a suitable microphone includes Resistance Technology&#39;s (the assignee of the present application) Intellimic™ microphone In the configuration shown in the Figures, the microphone ports are typically spaced between 6 to 13 mm. A distance of 30 to 35 mm is ideal. Such a design balances ergometric and acoustical properties. Ideally, spacing between ports should be between 6 inches or 8 inches to provide maximum low frequency detection below 2 KHz.  
         [0015]    With the two microphone ports spaced at 30 mm, performance above 5 dB is improved and such spacing makes it possible to use digital signal processing (DSP) to steer the acoustical beam and make it adaptable to changing noisy environments.  
         [0016]    Key features of the invention include either two omni-directional or two unidirectional microphones. Two directional microphones give higher performance results.  
         [0017]    The microphone ports are preferably disposed on the same plane and aligned in the same direction (along parallel axes).  
         [0018]    With DSP, this invention has an adaptive beam forming system in contrast to the fixed beam systems that are used presently.  
         [0019]    An alternative embodiment of the present invention includes an in-the-ear and a behind-the-ear configuration generally indicated at  50  in FIG. 3. The in-the-ear component is referenced at  52  while the behind-the-ear component is referenced at  54 . The components  52  and  54  are connected through a flex coil connection  56  that is coated. Component  52  contains an in-the-ear directional microphone  58  and component  54  contains a behind-the-ear directional microphone  60 , respectively. The ports of each microphone  58  and  60  are disposed in the same plane and aligned along parallel axes. Preferably, the microphone  60  in the behind-the-ear component  54  is positioned on the lower front side of the component  54  that is closest to the earlobe  24 .  
         [0020]    In one embodiment, all of the electronics of the hearing aid are moved into the behind-the-ear component  54  so that in-the-ear component  52  can be made very small with only a microphone  58  and receiver (not shown) for improved fitting geometry.  
         [0021]    [0021]FIGS. 4 through 7 illustrate a faceplate  100  of an in-the-ear hearing aid  102  having a beam forming array body  104  secured to the faceplate  100  by a ball  106  and a socket  108  assembly. The beam forming array body  104  includes a pair of spaced apart microphones  110  and  112  with corresponding spaced apart microphone ports  114  and  116 .  
         [0022]    The beam forming array body  104  is rotatable through the ball  106  and socket  106  and  108 . Two omni-directional microphones are positioned within the beam forming array body  104 , however, directional microphones may also be used. Wiring or electrical contacts are not shown in FIGS. 4 through 7.  
         [0023]    The beam forming array body  104  is detachably removable from the faceplate  100 . The ball and socket  106 ,  108  arrangement permits the beam forming array body  104  to be snapped into connection with the faceplate  100 . One advantage of the beam forming array body  104  is that the component portion of the hearing aid that is below the faceplate  100  and is disposed within the ear is standardized. Thereby, microphone changes can be made in the beam forming array body  104  for customization without having to customize the components of that portion of the hearing aid disposed within the ear.  
         [0024]    Another advantage of the beam forming array body  104  is that since both microphones are in the array, which is positioned away from the components below the faceplate  100 , acoustical feedback is eliminated from the hearing aid. Typically, the microphones are attached to the inside, below the faceplate  100 , of the in-the-ear portion of the hearing aid.  
         [0025]    Another advantage of the beam forming array body  104  is that both microphones are disposed in the same plane and along parallel axes which improves directivity pickup by the microphones.  
         [0026]    The ball and socket  106 ,  108 , construction requires strength and integrity to hold the beam forming array body  104  in position. The ball and socket  106 ,  108  can be made smaller than illustrated in FIGS. 4 through 7, and may be made of titanium or other metals that permit the ball and socket arrangement  106 ,  108  to be very small while very strong.  
         [0027]    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.