Abstract:
A mechanism for detachably mounting an earpiece having a receiver and an acoustic tube to any one of a variety of hearing aids includes using an adhesive and a clip attached to the acoustic tube to adhere the clip and thus the earpiece to a surface of the hearing aid, so that an open end of the acoustic tube is near an acoustic aperture of the hearing aid and can thus provide an acoustic sound signal to a microphone within the hearing aid. Alternatively, the clip can be provided with a magnet and a ferric plate can be fixed to a surface of the hearing aid, so that magnetic forces between the magnet and the ferric plate will attach the earpiece and the hearing aid together. The magnet and the ferric plate can be chosen so that the earpiece will separate from the hearing aid when a relative force between the earpiece and the hearing aid exceeds a predetermined threshold, thus preventing injury to a user wearing the hearing aid and the earpiece.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a two-way communications earpiece for use with a hearing aid. 
     2. State of the Art 
     Conventional two-way communications gear such as headsets and telephone handsets can present difficulties when used with hearing aids. In particular, the portion of the headset or telephone handset that rests against a user&#39;s ear can create a closed volume that reflects any sound leaking out of the user&#39;s ear from the hearing aid, back to the hearing aid microphone. An unpleasant positive feedback situation quickly develops which degrades the effectiveness of the hearing aid and can make conversation impossible. 
     Furthermore, cell phones can generate amplitude-modulated signals that interfere with hearing aids. For example, cell phones that employ the GSM standard commonly used in Europe, communicate with base stations at radio frequencies using digital signals. The communications are typically performed using time-division-multiple access (TDMA) protocols, so that the cell phone periodically transmits data in digital form over a radio frequency (RF) carrier wave. Between time slots, the carrier wave is turned off. The repetition frequency of the time slots can be on the order of about 220 Hz. In other words, even though the carrier wave is at a radio frequency and carries digital information, it is turned on and off at about 220 Hz and thus constitutes an amplitude modulated signal having a fundamental frequency of about 220 Hz. The radio frequency of the cell phone carrier wave is typically high enough that electrical components and lines within the hearing aid act as antennae and receive the carrier wave when the cell phone is close to the hearing aid, for example pressed against the user&#39;s ear. Circuit components within the hearing aid rectify the carrier wave and unintentionally recover the modulation. Although the electrical noise generated in the hearing aid by this unintended reception is small in magnitude, it can occur in the early, pre-gain stages of the hearing aid and thus be substantially amplified by the time it passes through the gain stages and appears at the output, for example a speaker, of the hearing aid. In this way a cell phone can introduce noise having a fundamental frequency of about 220 Hz into the hearing aid, and that frequency plus its harmonics are well within the frequency range of the human ear, which can significantly interfere with the user&#39;s ability to understand speech or other sounds relayed by the hearing aid. 
     In addition to the RF pulses radiated by the GSM cell phones and other cell phones using similar RF methods, the act of turning the RF transmitter on and off causes the current drawn by the cell phone circuitry to pulse up and down at the same rate that the transmitter is turned on and off. This generates magnetic pulses. If a cell phone of this type is held to the ear of a user wearing a hearing aid equipped with a pickup telecoil, then the telecoil will detect the magnetic pulses. The resulting signal from the telecoil pickup is large enough that it can render the hearing aid unusable in this mode, even if the hearing aid is shielded against the RF pulses. 
     U.S. Pat. No. 5,796,821 to Crouch, et al. (Crouch) discloses a hearing aid telephone interconnect system (HATIS) that provides an output audio electronic signal originally intended for a speaker in a telephone handset, stereo sound system, television set, etc. to a coil in a “T-coupler” device located near a user&#39;s pickup telecoil-equipped hearing aid. The T-coupler includes a coil. Based on the electronic signals, the coil generates electromagnetic waves in the audio frequency spectrum. The pickup telecoil in the hearing aid receives the electromagnetic signal generated by the coil, and the hearing aid uses the received signal to provide a corresponding acoustic signal to the user. 
     U.S. Pat. No. 5,761,319 to Dar, et al. (Dar) discloses an instrument for augmenting the versatility of an in-the-ear (ITE) hearing aid or a completely-in-the-canal (CIC) hearing aid. In particular, Dar discloses an instrument mounted behind the ear and including a receiver for receiving wireless signals, an electroacoustic transducer for generating acoustic sound signals corresponding to the wireless signals, and a tube that is positioned near the hearing aid to convey the acoustic sound signals to a microphone or acoustic pick up port of the in-the-ear hearing aid. 
     SUMMARY OF THE INVENTION 
     The present invention accurately and efficiently relays incoming signals to a hearing aid from a two-way communications device, such as a cell phone, without inducing electronic interference or acoustic feedback. An exemplary embodiment of the invention includes an earpiece having a breakaway mount for attaching the earpiece directly to a hearing aid worn by a user, and an acoustic tube that conveys sound from a speaker in the earpiece to an acoustic aperture in an outer housing of the hearing aid. The breakaway mount can accurately position the acoustic tube near an acoustic pickup of the hearing aid, such as an acoustic aperture that directs acoustic sound to a microphone within the hearing aid, so that the acoustic tube can efficiently provide acoustic sound signals to the hearing aid. The earpiece can also include a microphone for picking up the user&#39;s voice and surrounding sounds, and relaying corresponding signals back to the two-way communications device. 
     The breakaway mount allows the earpiece to be mounted on a variety of hearing aids including in-the-ear (ITE), in-the-canal (ITC), and behind-the-ear (BTE) hearing aids. The earpiece can break away from the hearing aid when force is applied to the earpiece, so that force will not be transferred to the hearing aid and potentially injure the user. The earpiece can also be quickly and easily mounted on, or dismounted from, the hearing aid by the hearing aid wearer depending on the wearer&#39;s particular needs at any given time. For example, the hearing aid wearer can easily mount the earpiece on, or easily dismount the earpiece from, the hearing aid while wearing the hearing aid. 
     Some hearing aids are provided with a pickup telecoil, which can receive sound in the form of electromagnetic waves in the audio frequency spectrum. To take advantage of this feature, an exemplary embodiment of the earpiece is provided with a transmitter telecoil that is connected to a transceiver within the earpiece. The earpiece transceiver can then drive the transmitter telecoil to generate electromagnetic waves in the audio frequency spectrum, which are received by the pickup telecoil in the hearing aid. Thus, the earpiece can provide an electronic sound signal directly to the hearing aid via an electromagnetic link between the transmitter telecoil in the earpiece and the pickup telecoil in the hearing aid. The electronic sound signal provided by the transmitter coil can either accompany or replace the acoustic sound signal conveyed by the acoustic tube to the hearing aid. When both are provided, the hearing aid user can control whichever signal is desired using the standard microphone/telecoil switching function provided in telecoil equipped hearing aids. Unlike the HATIS device, the earpiece also includes an acoustic microphone that picks up sounds ambient to the earpiece, such as the user&#39;s voice, and can provide the microphone output signal to the transceiver so that the sounds picked up by the microphone can be transmitted or conveyed to a remote device. The remote device can be the same device from which the transceiver is receiving signals for transfer to the hearing aid via the transmitter telecoil in the earpiece and the pickup telecoil in the hearing aid. The remote device can be, for example, a cell phone. 
     Generally speaking, exemplary embodiments of the invention relate to a two-way communications earpiece for use with a hearing aid, including a microphone for picking up sounds ambient to the earpiece, an acoustic tube for providing acoustic sound to a microphone in the hearing aid, and a mount for detachably mounting and orienting the earpiece on the hearing aid so that when the earpiece is mounted on the hearing aid, an end of the acoustic tube is near the hearing aid microphone and the acoustic tube can convey acoustic sound generated by the transducer in the earpiece to at least one of an acoustic aperture and a microphone in the hearing aid, while leaving the hearing aid microphone unobstructed to ambient sounds. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of preferred embodiments, when read in conjunction with the accompanying drawings. Like elements have been designated with like reference numerals. 
     FIG. 1A is a block diagram of an exemplary embodiment of the invention. 
     FIG. 1B is a block diagram of another exemplary embodiment of the invention. 
     FIG. 2 shows an exemplary embodiment of the invention. 
     FIGS. 3A-3C show components of an exemplary embodiment of the invention separately and in combination. 
     FIGS. 4A-4D show components of another exemplary embodiment of the invention separately and in combination. 
     FIGS. 5A-5C show different exemplary embodiments of the invention including a transmitter telecoil. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1A is a block diagram in accordance with an embodiment of the invention. 
     In particular, FIG. 1A shows an earpiece  102  connected via a wireless link  101  to a remote transceiver  100 . The remote transceiver can be, for example, a cell phone, a two-way radio, a radio transmitter, or other communications device. The earpiece  102  includes an acoustic tube  122  which attaches to the hearing aid  112  and conveys acoustic sound signals to the microphone  118  of the hearing aid  112 . 
     The earpiece  102  can also include a two-way radio transceiver, a microphone for picking up speech of a user wearing the earpiece, and a speaker or other transducer for producing sound in response to an electronic signal from the receiver. 
     In particular, the earpiece  102  includes a two-way radio transceiver  106  that can both send electromagnetic signals to, and receive electromagnetic signals from, the remote transceiver  100 . Those skilled in the art will understand that the transceiver  106  can be a transponder, and the transceiver  100  can be an interrogator associated with the transponder, or vice versa. An exemplary transponder that can be used with various embodiments of the invention is described in U.S. Pat. No. 5,721,783 to Anderson, which is hereby incorporated by reference. 
     The transceiver  106  can also receive signals from the microphone  108 , and relay the signals from the microphone  108  to the remote transceiver  100 . To convey sound signals to the user, the transceiver  106  can drive a speaker  110  to generate an acoustic sound signal in accordance with the signal received from the remote transceiver  100 . The acoustic sound signal from the speaker  110  is provided to one end of the acoustic tube  122 , and the other end of the acoustic tube  122  emits the acoustic sound signal. The emitter end of the acoustic tube  122  can be mounted on the hearing aid  112  so that it is located near an acoustic aperture  124  of the hearing aid  112 , to provide the acoustic sound signal to the microphone  118  of the hearing aid  112  via the acoustic aperture  124 . 
     The earpiece  102  can also be provided with a transmitter telecoil  104 . When the hearing aid  112  is also provided with a pickup telecoil  114 , the transmitter telecoil  104  can be used to transmit an electromagnetic audio frequency signal to the pickup telecoil  114  via an electromagnetic link  105 . The hearing aid  112 , which represents an exemplary hearing aid that is commercially available, also includes a signal processor  116  for receiving signals from the pickup telecoil  114  and/or the microphone  118 . The signal processor then provides an output signal to the speaker  120  to relay sound to the user. 
     The sound picked up by the microphone  108  in the earpiece, for example the user&#39;s own voice, can be fed back to the hearing aid  112  via the remote transceiver  100 . At the same time, the microphone  118  in the hearing aid  112  can also pick up the user&#39;s voice and other ambient sounds. 
     As shown in FIG. 1B, a wire connection  103  can be used instead of the wireless connection  101  to link the remote transceiver  100  with the earpiece  102 . FIG. 1B also explicitly shows that the acoustic tube  122  can be used, for example, in addition to or instead of the electromagnetic link  105 , to convey acoustic sound signals from the earpiece  102  to the hearing aid  112 . 
     The transceiver  106  in the earpiece  102  can be configured to communicate with the remote transceiver  100  when the remote transceiver  100  is connected to the earpiece  102  via the wired link  103  or the wireless link  101 . The remote transceiver  100  can be located at a distance from the hearing aid  112 , to allow any audio frequency electromagnetic noise generated by the remote transceiver  100 , such as noise caused by switching a cell phone carrier wave, to attenuate sufficiently before reaching the hearing aid  112 . Thus, when for example the remote transceiver  100  is clipped to the user&#39;s belt, the portion of electromagnetic noise generated by the remote transceiver  100  that reaches the hearing aid  112  at the user&#39;s ear is small enough that any adverse effect it has on the hearing aid  112  is negligible. 
     FIG. 2 shows an external view of an earpiece  200  that includes the elements of the earpiece  102  shown in FIG.  1 A. In particular, FIG. 2 shows the microphone  108  mounted on one end of the earpiece  200  with the acoustic tube  122  mounted near the microphone  108 , and the wired link  103  attached to the other end. The earpiece  200  can be very thin, so that it will fit next to a BTE hearing aid. The acoustic tube  122  can be fixed in the body of the earpiece  200 . The acoustic tube  122  can also be initially provided with an excess length, for example three inches, which can then be trimmed to an appropriate length for a particular user. In accordance with an embodiment of the invention, the attachment between the tube  122  and the earpiece  200  is stronger than the attachment between the tube  122  and the hearing aid, so that the tube  122  will release from the hearing aid before releasing from the earpiece  200  in a breakaway situation. 
     FIG. 3A is a detailed view of the free end of the acoustic tube  122 , and FIG. 3B shows a clip  312  having an adhesive layer  314 . The adhesive layer  314  can be a piece of double sided tape, or can be any other adhesive that has good bonding characteristics with the clip  312  and an outer surface of the hearing aid  316 . As shown in FIG. 3C, the clip  312  can be adhered to an outer surface of a hearing aid  316  so that when the tube  122  is inserted into the clip  312 , an end of the tube  122  is near a microphone aperture  322  in the hearing aid  316 . The clip  312  can be designed to release the tube  122  if excess force is applied to the earpiece  200 . Alternatively, the adhesive layer  314  can be selected so that the adhesive bond will release if shear and/or tensile forces on the adhesive bond exceed predetermined limits. Those of ordinary skill in the art will recognize that the predetermined limits can be chosen in accordance with principles well known in the art to prevent injury to the user. The clip  312  can also be designed so that the user can easily insert the tube  122  into the clip  312  on the hearing aid  316  by feel, while wearing the hearing aid  316 . 
     FIGS. 4A-D show an alternate method for attaching the acoustic tube  122  to the hearing aid  316 . As shown in FIG. 4A, the acoustic tube  122  can be inserted into a clip  412  having a magnet  413 , or the magnet  413  can be permanently attached to the tube  122 . As shown in FIG. 4B, a ferric plate  418  is provided on one side with an adhesive layer  414  such as double sided tape. As shown in FIG. 4C, the ferric plate  418  is adhered to an outer surface of the hearing aid  316  near the microphone aperture  322 , and the magnet  413  holds the clip  412  and the tube  122  against the ferric plate  418  so that sound emitted from the end of the tube  122  can enter the microphone aperture  322 . Using the magnet  413  allows the acoustic tube  122  (and the earpiece connected to it) to be attached and detached an indefinite number of times without degrading the strength or performance characteristics of the attachment. Using the magnet  413  also has an advantage in that the user can easily attach the earpiece to the hearing aid, since the magnetic attraction between the ferric plate  418  and the magnet  413  will help the user guide the tube  122  into position. The ferric plate  418  and the magnet  413  can be chosen so that the magnetic bond will release if shear and/or tensile forces on the magnetic bond exceed predetermined limits. Those of ordinary skill in the art will recognize that the predetermined limits can be chosen in accordance with principles well known in the art to prevent injury to the user. Alternatively, the clip  412  can be designed to release the tube  122  if excess force is applied to the earpiece  200 . 
     FIG. 4D shows a side view of the mounting configuration shown in FIG. 4C, with the adhesive layer  414  sandwiched directly between an outer surface  317  of the hearing aid  316  and the ferric plate  418 , with the magnet  413  on the opposite side of the ferric plate  418  from the adhesive layer  414 . Alternatively, a ferric plate can be molded directly into an outer surface of the hearing aid  316 , or otherwise permanently attached to the hearing aid  316 . 
     In addition to advantageously breaking away to prevent injury to the user when excess force is applied to the earpiece, the earpiece attachment structures described above and shown in FIGS. 3A-3C and  4 A- 4 D can be used to mount the earpiece on virtually any hearing aid. 
     Where an embodiment of the invention includes a transmitter telecoil in the earpiece, the transmitter telecoil can be separate and distinct from the earpiece speaker coil. Alternatively, the earpiece speaker coil can be configured to function as both the speaker driver and the transmitter telecoil. The different configurations of a) a separate transmitter telecoil and b) a dual purpose coil in the earpiece speaker, each have different advantages. For example, in an earpiece having a separate transmitter telecoil, the transmitter telecoil and the earpiece speaker coil can each be positioned and oriented to independently optimize their respective functions. On the other hand, an earpiece configured with a dual purpose earpiece speaker coil has fewer components than an earpiece having a separate transmitter telecoil, and can therefore be less expensive to manufacture, more compact and lighter in weight. 
     Where the earpiece transmitter telecoil is separate and distinct from the earpiece speaker coil, different electrical connections are possible. For example, FIG. 5A shows an embodiment wherein a transmitter telecoil  504  is connected in series with a speaker coil  508  across the transceiver  106 . FIG. 5B shows the telecoil  504  connected in parallel with the speaker coil  508  across the transceiver  106 , and FIG. 5C shows the telecoil  504  and the speaker coil  508  each having separate and independent electrical connections with the transceiver  106 . 
     Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof, and that the invention is not limited to the specific embodiments described herein. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all changes that come within the meaning and range and equivalents thereof are intended to be embraced therein.