Abstract:
A hearing aid includes a first portion adapted for behind-the-ear placement having a microphone, a second portion adapted for in-the-canal placement having a receiver and a cable that couples the first portion to the second portion, the cable having an adjustable length.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/010,748, filed on Jan. 11, 2008. The entire teachings of the above application are incorporated herein by reference. 
    
    
     BACKGROUND 
     In behind-the-ear (BTE) hearing aids, a cable connects a BTE unit to an earpiece unit via a plastic tube, through which the wires are routed. The plastic tube is preformed for either the left or right ear, and comes in different lengths (for example: small, medium and long) to accommodate different ear sizes. The cable/earpiece is generally attached to the BTE unit using an ultra-miniature electrical connector. The receiver earpiece fits in the ear canal in either an open or closed configuration. A hearing instrument professional is needed to select the cable for the user&#39;s right or left ear, create an earmold of the user&#39;s ear canal if the configuration is closed, determine the correct length cable for the user&#39;s ear, and attach the cable/earpiece to the main unit. The user typically is not given multiple cable/earpieces; if the user wishes to change the length or switch the hearing aid from one ear to the other, the user must return to the hearing instrument professional for service. 
     SUMMARY 
     The problems and shortcomings noted above are overcome by embodiments of the present invention. Accordingly, an embodiment of a hearing aid comprises a first portion adapted for behind-the-ear placement having at least a microphone, a second portion adapted for in-the-canal placement having at least a receiver, and a cable that couples the first portion to the second portion, the cable having an adjustable length. 
     An example hearing aid may include an enclosure adapted for behind-the-ear placement that houses a microphone for converting an acoustical input signal to an electrical signal and a sound processing circuit for processing the electrical signal; an earpiece adapted for in-the-canal placement that includes a receiver for converting the processed electrical signal to an acoustical output signal; a battery for powering the microphone, sound processing circuit and receiver; and an electrical cable that electrically couples the processed electrical signal from the sound processing circuit to the receiver, the cable extending from the enclosure with an adjustable length. The cable may be flexible to accommodate left/right usage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. 
         FIG. 1  illustrates a side perspective first embodiment of a hearing aid. 
         FIG. 2  illustrates the embodiment of  FIG. 1  with additional disk, ear-hook and retention elements. 
         FIG. 3  is an opposite side perspective view of the embodiment of  FIG. 1  with the foam disk element. 
         FIG. 4A  illustrates a half shell assembly view of the embodiment of  FIG. 1  with the foam disk element. 
         FIG. 4B  is an exploded view of an earpiece for the embodiment of  FIG. 1 . 
         FIG. 5  illustrates an opposite side view of the embodiment of  FIG. 1  with a test pad/programming element. 
         FIG. 6  illustrates a second embodiment of a hearing aid. 
         FIG. 7  illustrates a third embodiment of a hearing aid. 
         FIG. 8  illustrates an embodiment of a circuit block diagram for a hearing aid. 
     
    
    
     DETAILED DESCRIPTION 
     A first embodiment of a hearing aid shown in  FIG. 1  comprises an enclosure  102 , an earpiece  104  and a cable  106 . The enclosure  102  houses a microphone, sound processing circuitry, a battery (shown in  FIG. 4A ) and an on/off volume switch  118  that controls the gain of the microphone and the sound processing circuitry. The cable  106  connects signals from the enclosure  102  to a receiver (shown in  FIG. 4B ) in the earpiece  104 . 
     In an embodiment, the cable  106  runs through the body of the enclosure  102 , and then loops back into the enclosure, forming a loop  106 A. The cable  106  may be pulled through the enclosure  102  in either direction to either lengthen or shorten the distance between the enclosure and the earpiece  104 . A stop  120  at one end of the enclosure  102  provides a minimum radius for the cable  106 A and prevents the cable  106 A from being pulled too far into the enclosure. 
     The cable  106  has electrical wires that may be molded into clear insulation, e.g., clear silicone. The wires may be stranded to provide flexibility and durability. In some embodiments, the wire gauge and stranding configuration may be selected to provide a measure of formability to accommodate forming the cable for sizing and user comfort. A clear insulation allows the skin tones to show through, thereby making the cable less visible. In some embodiments, rounded or other cross-sectional shapes may be used for the cable  106 . Silicone is a good material to use since it is biocompatible and also provides sufficient friction against the skin to help prevent the hearing aid enclosure  102  from sliding. In some embodiments, other insulation materials (including, but not limited to, polyvinyl chloride, polyurethane, or other thermoplastic elastomers) or colors may be used. 
     The enclosure  102  may be made of a plastic or other light-weight material. The enclosure  102  is generally oblong in shape with a curved bottom surface  122  and lobes  124 ,  126 . 
     Embodiments of the hearing aid may be used on either the left or right ear. Since the cable  106  is flexible, the earpiece  104  may be twisted in the correct direction to be inserted into the ear. On the enclosure  102 , an acoustical sound port  116  channels sound to the microphone. The sound port  116  may be located along a symmetrical or almost symmetrical axis to provide proper sound pickup regardless of which ear the hearing aid is being worn on. Therefore, the same hearing aid may be used for either ear. 
     The earpiece  104  comprises a receiver (shown in  FIG. 4B ), handle  108 , tip  110 , wax guard  112  and receiver holder  114 . The receiver is mounted in the receiver holder  114 . The tip  110  may be made of a soft material, preferably silicon. An optional wax guard  112  made of reticulated foam may be attached to the tip  110 . Other types of wax guards may be used. 
     The handle  108  generally forms a T-shape with the receiver holder  114 . The handle  108  and the receiver holder  114  may be made of plastic, for example acrylonitrile butadiene styrene (ABS). Other types of materials may be used. The surface of handle  108  may be curved to better conform to the shape of a user&#39;s finger and angled away from the tip to provide a measure of strain relief for the cable  106  that connects to the receiver through a top portion of the handle  108 . In some embodiments, the connection between the cable  106  and the handle  108  may include a connector/receptacle configuration (e.g., an ultra-miniature electrical connector). 
     The handle  108  further provides a means for the user to insert the earpiece  104  to a proper and consistent depth within the ear canal. In particular, the handle  108  may be sized to prevent the tip  110  from touching the bony portion of the user&#39;s ear canal. Additionally, the handle  108  may prevent the user from inserting the tip  110  too deeply into the ear canal so as to avoid injury to the tympanic membrane. 
       FIG. 2  illustrates the hearing aid of  FIG. 1  with additional optional elements, including a disk element  202 , a retention element  204  and an ear hook element  206 . 
     The optional disk element  202  may be positioned around the receiver holder  114  between the handle  108  and the tip  110  of the earpiece  104 . The disk element  202  may be made of a foam or other suitable material. The disk element  202  absorbs sound and helps avoid feedback between the microphone and the receiver. In addition, the disk element  202  helps to retain the earpiece  104  in the ear canal. 
     The optional retention cord or loop element  204  may be attached to the handle  108  and positioned in the concha of the pinna to help retain the earpiece  104  in the ear canal. The retention element  204  may be sized for different sized ears. The retention element  204  may be optionally attached and detached by the user, or may be permanently attached at the time of manufacture. 
     The optional ear hook  206  is attachable to the enclosure  102  to help position the enclosure  102  relative to the user&#39;s ear. The ear hook  206  may be optionally attached and detached by the user, or may be permanently attached at the time of manufacture. 
       FIG. 3  is an opposite side perspective view of the embodiment of  FIG. 1  with the foam disk element  202  in place.  FIG. 4A  illustrates a half shell assembly view of the embodiment of  FIG. 1 . In this view, one half of the enclosure  102  has been removed to show battery  402  and microphone and sound processing circuitry  404 . The battery  402  is mounted in a recess  426 . The microphone and sound processing circuitry  404  are mounted in a recess  424 . The on/off volume switch  118  is mounted between the recesses  424 ,  426 . A printed circuit board (not shown) provides electrical connections between the battery  402 , microphone and sound processing circuitry  404  and the on/off volume switch  118 . 
     The enclosure  102  has openings  428 ,  430  at one end through which the adjustable cable loop  106 A passes. The cable  106  passes through opening  432  at the other end of the enclosure  102 . 
     In an embodiment, the cable  106  may be held in its position by friction between the cable and the enclosure  102 . As shown in  FIG. 4A , a compliant element  406  may be positioned between a portion of the cable  106  and a guide  412  in the enclosure  102  to provide a force against the cable  106  as a means of friction. The compliant element  406  may be one of a piece of foam, a plastic spring, a metal spring, or other means of providing a force. In another embodiment, frictional force is provided by routing the cable  106  through a slightly torturous path or through a pinch-point, such that the cable rubbing on one or more guides  410 ,  414 ,  416  in the enclosure creates the friction. The cable  106  may be further guided along a channel formed by the guides  410 ,  414 ,  416 . In other embodiments, other means, either continuously adjustable or discretely adjustable, may be used to adjust and maintain the length (e.g., sprockets, press-fit means, pin-and-hole like a belt adjustment, etc.). 
       FIG. 4B  is an exploded view of an example earpiece  104 . Receiver  440  may be mounted in opening  114 A of receiver holder  114 . Cable  106  may be received through strain relief element  108 A which fits in opening  108 B of handle  108 . 
       FIG. 5  illustrates the embodiment of  FIG. 1  with a test pad/programming element  502  that extends through an opening  504  of the enclosure  102 . The test pad/programming element  502  provides electrical access to the electronic circuitry of the hearing aid for the purposes of testing and programming features. 
     In a second embodiment of a hearing aid  600  shown in  FIG. 6 , the wires do not loop outside the body of the enclosure; rather, the wires split off within the enclosure  602  and a tail portion  624  extends from the enclosure to aid in adjusting length. In this embodiment, the earpiece  604  is attached with a flexible wire  606  up to the point of a coupler  626  located intermediate the enclosure  602 . The wires then exit the coupler  626  and are soldered to a printed circuit board (not shown) within the enclosure. The wires have sufficient slack  630  (excess wire) to allow adjustment of the length between the enclosure  602  and the earpiece  604 . A semi-flexible cord (or tail)  624  exits the other end of the coupler  626  and out from the enclosure  602 . The user may use the tail  624  to push or pull the coupler  626 , which in turn adjust the length between the earpiece  604  and the enclosure  602 . Since the tail  624  does not contain any wiring, it may be cut by the user to a desired length. The tail  624  is also curved inwards toward the ear, and may help in retaining the hearing aid on the user&#39;s ear. 
     The enclosure  602  houses microphone and sound processing circuitry  628 , battery  632  and includes on/off volume control switch  618 . The earpiece  604  includes elbow-shaped handle  608 , tip  610  and wax guard  612 . The handle  608  may be rotated about the cable  606  to accommodate left/right usage. 
       FIG. 7  illustrates a third embodiment of a hearing aid  700 . This embodiment is similar to the first embodiment in that the cable  706 A is looped through the enclosure  702  to allow adjustment of the cable length. The enclosure  702  includes on/off volume control switch  718 , battery and microphone/sound processing circuitry (not shown). A tubing sleeve  726  provides an over-ear hook for retention and positioning of the hear aid. Earpiece  704  includes handle  708 , tip  710  and wax guard  712 . The cable  706  slides in and out of tubing sleeve  726  to allow for an adjustable length. Handle  708  is rotatable about another tubing sleeve  714  that locks position at the end of travel for left/right usage. 
     In some embodiments, the hearing aid is fully disposable, in that the battery is integral to the hearing aid and is not replaceable by the user. Therefore, when the battery is depleted, the entire hearing aid may be discarded. In a partially disposable embodiment, the earpiece comprises at least a battery, receiver, cable and means of connection to the enclosure containing microphone and sound processing circuitry. When the battery is depleted, the earpiece is replaced with a new earpiece while the enclosure containing the microphone and sound processing circuitry may be reused. 
       FIG. 8  shows an example circuit block diagram for use in any of the hearing aid embodiments described herein. The hearing aid circuit  800  includes a microphone  802 , sound processing circuitry  804 ,  806 ,  808 ,  810 ,  812 ,  814 ,  816  and a receiver/speaker  818 . A battery not shown supplies power to the circuitry  800 . Sound is received by the microphone  802  and converted into an electrical signal. A preamplifier  804  amplifies the signal to appropriate levels within the circuit. The preamplifier  804  also has a programmable gain function and is programmed to compensate for tolerances in the microphone sensitivity. The signal then passes through a compression limiter circuit  806  that prevents loud sounds from overloading the circuit&#39;s signal path. Following the compression limiter  806  is an analog-to-digital converter (ADC)  808 . While different types of ADCs may be used, some embodiments use a sigma-delta modulator based converter. The ADC  808  converts the analog signal into its digital representation. The digital signal then passes through a filter bank  810 . In the embodiment shown, a two-band filter is employed. In other embodiments, the filter bank may use more than two filter bands. The outputs from the filter bank  810  pass through another compression circuit  812  that is configured to provide a Treble-Increase-at-Low-Levels (TILL) function. The output of the TILL compressor  812  is summed  814  with a fraction of the LO-band output from the filter bank  810 , and then is processed by a digital amplifier  816 . In an embodiment, the digital amplifier  816  is another sigma-delta modulator. This digital amplifier  816  also has programmable gain, used to compensate for tolerances of the receiver (speaker) sensitivity. The output of the digital amplifier  816  drives the receiver  818  that converts the digital signal back into sound. 
     More complex or less complex sound processing circuitry may be used with example embodiments. 
     While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.