Abstract:
One exemplary device, a hands-free adapter for use with ANR headphones, includes a microphone and two stereo-type plugs electrically coupled via a cable. The first stereo-type plug connects to a hands-free jack of a mobile telephone, and the second plugs connects to the audio-input jack of the headphones. The microphone is mounted on the second plug and electrically coupled through the cable and the first plug to a microphone input portion of the hands-free jack. This arrangement allows convenient and unprecedented use of the ANR headphones with the mobile telephone or other suitably equipped communication devices.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to co-pending U.S. provisional application 60/563,716, filed Apr. 20, 2004. The provisional application is incorporated herein by reference. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention concerns headphones and related circuits, accessories, and methods.  
       BACKGROUND  
       [0003]     Headphones are used in variety of applications to facilitate private listening of devices, such as stationary and portable stereos, digital video players, digital music players, computers, and so forth. Some of these headphones are equipped with automatic noise reduction (ANR) circuitry. This circuitry automatically cancels or suppresses loud persistent ambient noise within the headphones, allowing users to enjoy an electronically controlled silence or an improved listening experience.  
         [0004]     A seminal example of ANR headphones is the Quiet Comfort™ line of headphones from Bose Corporation of Framingham, Mass. Bose recently released a new version of these headphones, Quiet Comfort 2™, which incorporates improvements, such as a fold-flat design for more space-efficient storage and integration of its ANR electronics and battery box into its earcups. (Quiet Comfort and Quiet Comfort 2 are presently believed to be trademarks of the Bose Corporation.) The new version also includes an audio input plug with a built-in audio attenuator. The audio attenuator has a high-low switch to reduce or attenuate the volume of audio signals input to the headphones. The audio input plug is coupled via an insulated multi-wire electrical cable to a standard ⅛-inch male headphone plug, which is compatible with the female audio output of most laptops, and portable video and music players.  
         [0005]     Despite these improvements, the present inventor has recognized that the Bose Quite Comfort headphones, as well as other competing ANR headphones, are not readily adaptable for use with two-way communications devices, such as cordless or mobile telephones, or for simultaneous connection to more than one audio source. For example, the Quiet Comfort and other headphones are typically provided with a two-prong-plug adaptor for coupling the headphone plug to the audio output port typically found in commercial airliners. It is also typical to provide an adapter for coupling the ⅛-inch headphone plug to a ¼-inch stereo phone port commonly found on stationary home stereo and entertainment systems. However, none of these adapters allow use of the ANR headphones with two-way communications devices or multiple audio sources.  
         [0006]     Accordingly, the present inventor has identified unmet needs to expand the utility and ultimately the value of ANR headphones.  
       SUMMARY  
       [0007]     To address this and/or other needs, the present inventors devised one or more systems, devices, circuits, and methods for expanding the utility and value of ANR and non-ANR headphones. One exemplary device, a hands-free adapter for use with ANR headphones, includes a microphone and two stereo-type plugs electrically coupled via a cable. The first stereo-type plug connects to a hands-free jack of a mobile telephone, and the second plugs connects to the audio-input jack of the headphones. The microphone is mounted on the second plug and electrically coupled through the cable and the first plug to a microphone input portion of the hands-free jack. This arrangement allows convenient and unprecedented use of the ANR headphones with the mobile telephone. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]      FIG. 1  is a block diagram of an exemplary system  100  corresponding to one or more embodiments of the present invention.  
         [0009]      FIG. 2  is a partial electrical schematic of system  100 , corresponding to one or more embodiments of the present invention.  
         [0010]      FIG. 3  is a block diagram of an exemplary system  300  corresponding to one or more embodiments of the present invention.  
         [0011]      FIG. 4  is an electrical schematic of system  300 , corresponding to one or more embodiments of the present invention.  
         [0012]      FIG. 5  is an exemplary electrical schematic of a source selector component of system  300 , corresponding to one or more embodiments of the present invention.  
         [0013]      FIG. 6  is a partial perspective view of an exemplary earpiece-and-connector subassembly  600  for systems  100  and  400 , which corresponds to one or more embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0014]     The following detailed description, which references and incorporates the attached Figures, describes and illustrates one or more specific embodiments of the invention. These embodiments, offered not to limit but only to exemplify and teach, are shown and described in sufficient detail to enable those skilled in the art to implement or practice the invention. Thus, where appropriate to avoid obscuring the invention, the description may omit certain information known to those of skill in the art.  
         [0015]      FIG. 1  show an exemplary system  100  corresponding to one or more embodiments of the present invention. System  100  includes ANR headphones  110 , an adapter  120 , and a communications device  130 . System  100  can be sold or offered as a complete system, as separate components, or as subcombination kits. For example, one exemplary kit includes headphones  110  and adapter  120 , and another exemplary kit includes communications device  130  and adapter  120 .  
         [0016]     ANR headphones  110  includes earpieces  112  and  114  and a bridge member  116 . Earpieces  112  and  114 , each of which take an over-the-ear (circumaural) form in the exemplary0 embodiment, fit over or engage respective ears of a user (not shown). In some embodiments, the earpiece take on-the-ear, in-the-ear, or behind-the-ear form.  
         [0017]     Specifically, earpiece  112 , which is mechanically connected to earpiece  114  via bridge member  116 , includes ANR circuitry  1121 , an ANR microphone  1122 , an ANR speaker  1123 , a non-ANR speaker  1124 , a battery compartment  1125 , and an audio input jack  1126 . In the exemplary embodiment, earpiece  114  is substantially identical to earpiece  112  with the exception of battery compartment  1125  and audio input jack  1126 ; thus, for sake of brevity, no further description of earpiece  114  is given. Bridge member  116 , in some embodiments, folds in half. Also in some embodiments, earpieces  112  and  114  each rotate inwardly (toward the region between the earpieces.)  
         [0018]     ANR circuitry  1121 , which is powered for example by one or more AA or AAA batteries in battery compartment  1125 , responds to a range of low-frequency acoustic energy sensed via ANR microphone  1122  by driving ANR speaker  1123  to produce an opposing acoustic signal. The opposing acoustic signal destructively interferes with the low-frequency acoustic energy, thereby reducing its magnitude and improving the clarity of acoustic signals from non-ANR speaker  1124 . Speaker  1124  is driven via electrical signals from a right-channel contact  1126 R of audio input jack  1126 —which includes a ground contact  1126 G, a right-channel contact  1126 R, and a left-channel contact  1126 L—is coupled or couplable to adapter  120 . (In the figures, the numerical prefixes for the contacts are omitted.)  
         [0019]     Adapter  120  includes a headphone-microphone connector  121 , a cable  122  and a device connector  123 .  
         [0020]     Headphone-microphone connector  121 , which in the exemplary embodiment takes the form of three or four-contact male or female stereo plug connector, includes a connector housing  1211 ; a multi-contact stem or socket  1212 ; controls  1213 ; and a boom microphone assembly  1214 . Connector housing  1211 , formed by molding a durable insulative material, such as plastic, holds multi-contact stem  1212  and supports boom microphone assembly  1213 . Multi-contact stem  1212  includes a ground contact region  1212 G, a right-channel contact region  1212 R, and a left-channel contact region  1212 L, which make electrical contact with respective contacts of  1126 G,  1126 R, and  1126 L when connector  121  is properly engaged with audio input jack  126 . (The figure omits the  1212  prefix from the contact reference labels.) Controls  1214  include one or more switches, potentiometers, or other devices for muting or adjusting the volume of signals output from connector  121  to headphone  110 .  
         [0021]     Boom microphone assembly  1213  includes an boom  1213 A and a microphone  1213 B.  
         [0022]     Boom  1213 , which can be formed of flexible conduit, extends laterally from connector housing  1211  to support and position (or allow positioning of) microphone  1213  in a region suitable to promote sensing of audible signals from a user wearing headphones  110  equipped with adapter  120 . In some embodiments, microphone  1213 B is positioned in and/or on connector housing  1211  and boom  1213 A is a tube (or wave guide) acoustically bridging all or part of distance between microphone  1213 B and a user&#39;s mouth. (See, for example, U.S. application 20040062413, published Apr. 1, 2004, which is incorporated herein by reference.)  
         [0023]     Microphone  1213 B, in the exemplary embodiment, includes an unbuffered electret microphone. This type of microphone is generally suitable for use with microphone preamplifiers typically found in mobile and cordless telephone phones or other devices compatible with hands-free accessories. (Some embodiments also include, within the connector housing, a battery and a high-performance preamplifier for the microphone, thereby improving audio performance over the level provided by the preamp in the communications device.) Microphone  1213 B includes positive and negative contacts (not visible in the figure), which are coupled along with the contact regions of multi-stem  1212  to one or more insulated conductors in cable  122 . (Some embodiments incorporate a Bluetooth-compatible wireless transceiver and battery within connector housing  1211  to replace cable  1222 .)  
         [0024]     Coupled electrically to cable  1222  is device connector  122 . Device connector  122 , which in the exemplary embodiment takes the form of an ⅛-inch (2.5-millimeter) three-conductor stereo plug or socket, includes a connector housing  1221  and a multi-contact stem or socket  1222 . Connector housing  1221 , formed by molding a durable insulative material, such as plastic, holds multi-contact stem  1222 . Multi-contact stem  1222  includes a ground contact region  1222 G, a microphone contact region  1222 M, and a speaker contact region  1222 S., may use a, which make electrical contact with respective contacts of  1326 G,  1326 M, and  1326 S when connector  122  is properly engaged with hands-free jack (or connector)  132  on communications device  130 . (The figure omits the  1222  prefix from the contact reference labels.)  
         [0025]     Communications device (or system)  130  includes, among other items, an audio output jack  122  and an external microphone jack  124 . In the exemplary embodiment, communications device  120  takes the form of a cellular or cordless telephone, with output jack  122  and microphone jack  124  coupled to interface circuitry (not shown) which supports use of a conventional hands-free mobile-phone headset, which includes a microphone and an ear-piece (or headphones). (Hands-free headsets typically include an unbuffered electret microphone that is powered by interface circuitry (not shown) in the cell phone or other type secondary device. In the exemplary embodiment, this interface circuitry is not suitable for boom microphones in aviation headsets.) In some other embodiments, device  130  takes the form of a two-way radio, laptop computer, or other audio source or audio output device, such as a music or video player or other personal listening device. In some of these embodiments, connector  122  is implemented as two separate stereo plugs or connectors for use with communications devices having separate microphone and headphone jacks.  
         [0026]      FIG. 2  shows a partial electrical schematic of system  100 . The schematic highlights the electrical connections between headphone input jack  1126  and headphone-microphone connector (HMP)  123  and between device connector  123  and device hands-free jack  132 .  
         [0027]      FIG. 3  shows an exemplary headphone system  400  which in addition to previously described headphones  110  and two-way communications device  130 , includes a multi-source (or device) adapter  410  and an additional communications device  420 . In addition those components already described for adapter  120  in  FIG. 1 , multi-source adapter  410  includes a source selector  412 , a multi-conductor cable  414 , and a device plug  416 . Source selector  412 , which is positioned within the housing of headphone-microphone connector  1211 , is coupled via cable  122  to device connector  123  and via cable  412  to device connector  416 . Device connector  416 , which for example take the form of a 2.5 or 3.5 millimeter stereo plug connector, couples to the audio output jack of communications device  420 . Device  420  in some embodiment takes the form of a digital music or video player, such as an iPod music player or other MP3 player.  
         [0028]     In operation, source selector  412  normally couples device connector  416  (and thus communications device  420 ) to the stem of connector  1211  and thus to the audio input jack of headphones  110 . However, when device  130  generates a microphone bias signal, for example in response to receiving a phone call and ringing, a microphone bias signal is communicated through cable  122  to selector  412 . In response, selector  412 , which functions as a break-before-make multiplexer, decouples communications device  420  from the stem of connector  1211  and couples device connector  123  and thus device  130  to stem of connector  1211  and to the audio input jack of headphones  110 .  
         [0029]      FIG. 4  shows an exemplary electrical schematic for system  400 , which like  FIG. 2  highlights connections within adapter  410  and connection of adapter  410  to headphones  110  and devices  130  and  420 .  
         [0030]      FIG. 5  shows an exemplary implementation of source selector  412  in the form of circuit  500 . Circuit  500  includes dual SPDT (single-pole-double-throw) analog switch  510 , a low-pass RC filter  520 , and a battery  530 . One example of a suitable analog switch is part number FSA2267 from Fairchild Semiconductor of South Portland, Me. In the exemplary embodiment, batter  530  is a coin cell battery.  
         [0031]      FIG. 6  shows a perspective view of an exemplary earpiece-and-headphone-microphone subassembly  600 , which is applicable to systems  100  and  400 . Subassembly  600  includes an earpiece  610  and a headphone-microphone connector  620 . Earpiece  610  includes an sector or pie-shaped opening  612  which provides access to a socket of an audio input jack. Connector  620 , which is shown with two cables, has a housing  622  with a sector or pie-shaped portion that is sized to mate with pie-shaped opening  612  in earpiece  610 .  
       CONCLUSION  
       [0032]     The embodiments described above are intended only to illustrate and teach one or more ways of practicing or implementing the present invention, not to restrict its breadth or scope. The actual scope of the invention, which encompasses all ways of practicing or implementing the concepts of the invention, is defined by the following claims and their equivalents.