US20100111340A1 - Acoustic Valve Mechanisms - Google Patents

Abstract

A valve for a personal auditory system is described. The auditory system is capable of converting between an acoustic signal and an electrical signal. The auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system. The valve includes a free floating electrode and a second electrode adjacent to free floating electrode. An electric signal that is generated by the second electrode moves the free floating electrode to substantially open or close the acoustic pathway.

Description

CROSS REFERENCES TO RELATED APPLICATIONS
• This non-provisional application claims priority to U.S. Provisional Application No. 61/104,589 filed on Oct. 10, 2008 entitled “Acoustic Switch Mechanism” and U.S. Provisional Application No. 61/165,746 entitled “Acoustic Valve Mechanism” and filed on Apr. 1, 2009 the contents of both of which are incorporated herein by reference in their entireties.
TECHNICAL FIELD
• This patent application relates to acoustic valve assemblies which allow a vent to be created within an auditory system.
BACKGROUND OF THE INVENTION
• Hearing aids use directional microphones to improve the signal to noise ratio in locations where there are multiple sources of sound. The most useful source of sound is generally in front of the listener. If there are not many sources of sound, or if the useful source is not in front of the listener, it is advantageous to change the microphone directionality. This is accomplished in current hearing instruments by using more than one microphone. Most designs use a matched pair of omni-directional microphones. The microphones must be very closely matched, or the electronics must be able to compensate for any differences between the microphones. This is difficult to accomplish, adds to the overall expense of manufacturing, and reduces the reliability of the hearing instrument. Another approach is to use one-directional microphone and one non-directional microphones. The drawback of this approach is that three microphone openings are required on the surface of the hearing instrument.
• Receiver in Canal style hearing instruments are devices which are sold in open-fitting versions for people with mild impairment. The open fitting allows natural sound to reach the ear. This sound is supplemented by amplified high frequency sound from the hearing instrument receiver. The open fitting eliminates problems with occlusion, which makes the sound of chewing and one's own voice seem unnaturally loud. When the hearing instrument wearer is in a noisy environment, a closed fitting would be preferred. The closed fitting allows the instrument to have greater control over the sound to reach the ear. The closed fitting also offers increased directivity, noise reduction, and other features which increase intelligibility.
• A need, therefore, exists for a hearing instrument which can provide the benefits of open and closed fitting.
BRIEF DESCRIPTION OF THE DRAWINGS
• For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawings wherein:
• FIG. 1 is an exploded view of an acoustic vent assembly according to the present invention;
• FIG. 2 is a perspective view of the assembly ofFIG. 1;
• FIG. 3 is another perspective view of the assembly ofFIG. 1;
• FIG. 4 is a transparent side view of the assembly ofFIG. 1;
• FIG. 5 is a side view of a cam component of the assembly ofFIG. 1;
• FIG. 6 is a top plan view of the cam ofFIG. 5;
• FIG. 7 is a side view of a peg element of the assembly ofFIG. 1;
• FIG. 8 is a top plan view of the peg element ofFIG. 7;
• FIG. 9 is a close-up side view of the cam ofFIG. 5;
• FIG. 10 is a side transparent view of the cam and peg element of the preceding figures in a position allowing a vent to be open;
• FIG. 11 is a side transparent view of the assembly ofFIG. 1 in an open position (i.e., in which the vent allows air to enter and exit);
• FIG. 12 is a side transparent view of the cam and peg element of the preceding figures in a position in which the vent is closed;
• FIG. 13 is a side transparent view of the assembly ofFIG. 1 in a closed position;
• FIG. 14A is a perspective view of a magnetic valve assembly in an embodiment of the present invention;
• FIG. 14B is an exploded view of the assembly ofFIG. 14A;
• FIG. 15 is another exploded view of the magnetic valve assembly ofFIG. 14A;
• FIG. 16A is a perspective view of the valve assembly ofFIG. 14A in an open state;
• FIG. 16B is a perspective view of the valve assembly ofFIG. 14A in a closed state;
• FIG. 17 is a cross-sectional view of the assembly ofFIG. 14A in an open state;
• FIG. 18 is an isolated view of a valve assembly utilizing a balanced armature receiver as the valve in an embodiment of the present invention;
• FIG. 19 is a perspective view of a moving fluid valve assembly in an embodiment of the present invention;
• FIG. 20 is side cross-sectional view of the assembly ofFIG. 19;
• FIG. 21A is a side cross-sectional view of a moving magnet valve assembly in an embodiment of the present invention;
• FIG. 21B is a side view of the assembly ofFIG. 21A;
• FIG. 22 is a side cross-sectional view of a moving magnet valve assembly in an embodiment of the present invention;
• FIG. 23 is a side cross-sectional view of a moving magnet valve assembly in an embodiment of the present invention; and
• FIG. 24 is a perspective view of a magnetic valve assembly in which a moving magnet is attached to a film that acts as a spring.
• FIG. 25 is a cross-sectional view illustrating an acoustic switch mechanism according to the present invention;
• FIG. 26 is a perspective view of the acoustic switch mechanism ofFIG. 25 according to the present invention;
• FIG. 27 is a table of open and closed positions based on polarity, for a switch mechanism according to the present invention;
• FIG. 28 is a cross-sectional view of the acoustic switch mechanism ofFIG. 25 in an open position;
• FIG. 29 is a cross-sectional view of the acoustic switch mechanism ofFIG. 25 in a closed position;
• FIG. 30 illustrates an acoustic switch mechanism incorporated within a MEMS device according to the present invention; and
• FIG. 31 illustrates a switch mechanism within a microphone device in an embodiment of the present invention.
• Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.
DETAILED DESCRIPTION
• While the present disclosure is susceptible to various modifications and alternative forms, certain embodiments are shown by way of example in the drawings and these embodiments will be described in detail herein. It will be understood, however, that this disclosure is not intended to limit the invention to the particular forms described, but to the contrary, the invention is intended to cover all modifications, alternatives, and equivalents falling within the spirit and scope of the invention defined by the appended claims.
• The present invention generally relates to acoustic valve assemblies which may be part of auditory systems. The assemblies may be positioned within the auditory system, adjacent to a microphone/receiver, and between the speaker/microphone and the area outside the ear. Put another way, in an embodiment, the valve may be attached to the sealed back volume of a microphone. When the valve is open, the microphone will have a directional pattern. When the valve is closed, the pattern will be non-directional. Various methods are described below for actuation of the valve to create a vent within the auditory device or system, including mechanical actuation and electromagnetic actuation.
• In an embodiment, a valve is provided for a personal auditory system. The auditory system may be capable of converting between an acoustic signal and an electrical signal. The auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system. The valve has: a free floating electrode; a second electrode adjacent to free floating electrode; wherein an electric signal generated by the second electrode moves the free floating electrode to substantially open or close the acoustic pathway.
• In an embodiment, the valve also has a third electrode, wherein the free floating electrode is positioned between the second electrode and the third electrode, wherein an electric signal generated by the third electrode moves the free floating electrode to substantially open or close the acoustic pathway.
• In an embodiment, the valve is positioned within a microphone.
• In another embodiment, a valve is provided for an auditory system. The auditory system may be capable of converting between an acoustic signal and an electrical signal. The auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system. The valve has a housing; a magnetic member located within the housing capable of generating a magnetic force; an armature adjacent to the magnetic member wherein the magnetic member generates a magnetic force towards the armature; and a coil adjacent to the armature, wherein energizing of the coil attracts or repels the armature to substantially open or close the acoustic pathway.
• In an embodiment, the valve also has a spring member associated with the armature, wherein the spring member applies a force to the armature to open the acoustic pathway.
• In an embodiment, the valve also has a diaphragm coupled to the armature and positioned between the armature and the exterior of the auditory system wherein movement of the diaphragm opens or closes the acoustic pathway.
• In yet another embodiment, a valve is provided for an auditory system. The auditory system may be capable of converting between an acoustic signal and an electrical signal. The auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system. The valve has a magnetic member; and a coil substantially surrounding the magnetic member; wherein a magnetic field generated by the coil moves the magnetic member to substantially open or close the acoustic pathway.
• In an embodiment, the magnetic member is positioned within a housing and the coil surrounds the housing.
• In an embodiment, the housing has a port wherein movement of the magnetic member towards the port causes closing of the acoustic pathway.
• In an embodiment, the valve also has a sleeve attached to the magnetic member.
• In another embodiment, a valve is provided for an auditory system. The auditory system may be capable of converting between an acoustic signal and an electrical signal. The auditory system has a housing and further has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system. The valve has a peg element fitted within the housing; a spring member coupled to the peg element wherein the spring member provides a restoring force to the peg element; and means for actuation of the peg element from a first position to a second position within the housing wherein such actuation substantially closes the acoustic pathway in the second position; and means for locking the peg element, or releasing the peg element, from the second position.
• In an embodiment, the peg has a protruding member from a surface of the peg.
• In an embodiment, the means for locking the peg element comprises a cam formed in the housing having a grooved surface sized to receive the protruding member.
• In an embodiment, the acoustic pathway includes a port in the housing wherein the peg covers the port when the acoustic pathway is closed.
Mechanical Actuation (FIGS.1-13)
• FIG. 1 illustrates avalve assembly2 for creating a vent in an auditory system. Theassembly2 may have ahousing4 having apertures6 through which, for example, air may enter or exit. Illustrated at an end of thehousing4 is apeg element8 having a member orprotrusion9 extending from a surface of thepeg element8.FIGS. 7 and 8 provide side and top plan views of thepeg element8, which may be cylindrical in shape, although other shapes are possible as contemplated by those of skill in the art.Peg element8 may be constructed of or coated in a soft, compliant material such as rubber or silicone to improve sealing with apertures6. The inside ofhousing4 may alternatively be coated in a soft material to aid sealing. Theprotrusion9 may be integrally formed; or, in an embodiment, may be attached to asurface15 of thepeg element8. Acap10 anddriver12 are attached to thepeg element8. Thecap10 provides a point of contact for actuation of theassembly2, as will be described in more detail below.
• Acam14 is shown which fits concentrically around thepeg element8.FIGS. 5 and 6 provide side and top plan views, respectively, of thecam14. As seen inFIG. 5, thecam14 has achannel16 which is shaped to receive theprotrusion9 of the peg element. Theprotrusion9 may slide along thechannel16 as thevent2 is actuated. Different points along thechannel16 may correspond to open or closed positions of thevent assembly2. For example, and shown more closely inFIG. 9,location17 may correspond to a closed position whilelocation19 may correspond to an open position. Aspring18 is located adjacent to thecam14. An O-ring or seal20 and a base22 are adjacent to thespring18.
• FIGS. 2 and 3 illustrate perspective views of thevalve mechanism2 in an assembled position.FIG. 4 provides a transparent side view of theassembly2. As seen, thepeg element8 andcam14 are concentrically positioned. Thespring18 is positioned below thecam14. Thedriver12 rests adjacent to thepeg element8 and moves thepeg element8 when thecap10 is actuated. The components of theassembly2 may be constructed from, for example metal, plastic, or the like. An overall length of thevalve assembly2 may be in a range from 0.01 inches to 0.5 inches. It should be noted that the materials and dimensions described herein are provided for purposes of example and should not be construed as limiting the scope of the invention.
• The positioning of theprotrusion9 along thechannel16 is dependent upon actuation of thecap10. A first actuation (such as pressing down upon the cap10) may move theprotrusion9 fromlocation19 tolocation17 along thechannel16, thereby pushing thepeg element8 against thespring18 and putting theassembly2 in a closed position. A second actuation of thecap10 may cause thespring18 to place a force against thepeg element8 and subsequently move theprotrusion9 along thechannel16 back tolocation19 where it is held in an open position.FIG. 10 provides an isolated view of thecam14 andpeg element8 positioned whereby theprotrusion9 is at alocation19, which corresponds to thepeg element8 being above the apertures6. Accordingly, because thepeg element8 is not covering the apertures6, air or other fluids are allowed to vent, or flow, through the apertures6, as shown byarrows28 inFIG. 11.FIG. 12 provides an isolated view of thecam14 andpeg element8 positioned whereby theprotrusion9 is atlocation17, corresponding to a closed position, in which thepeg element8 covers the apertures6. This is also illustrated inFIG. 13. Thus, fluid is not able to pass through the apertures6.
Electromagnetic Actuation (FIGS.14-24)
• In another embodiment, the valve can be magnetically powered, so that the valve position can be controlled by the electronics of the hearing instrument. The electronics in turn may be controlled by a remote control, or a processing unit may make decisions regarding the best valve setting based on the acoustic signals picked up by the microphones. The valve can be mounted directly to the microphone, or be connected through tubing. The magnetic motor is designed to be bi-stable, so that power is only consumed when the valve changes state. No power is required in between changes of state.
EMBODIMENT 1Moving Armature
• In a first embodiment, illustrated inFIGS. 14-17, the magnetic design of the motor structure is similar to a “button” receiver used in prior art hearing instruments. Themagnetic assembly100 is made up of thecup102, pole piece103,magnet104, top plate111,magnet104 and armature106. The cup, pole piece and top plate are made of high permeability soft magnetic material, such as 50% iron/nickel alloy. For high efficiency, the motor provides a closed magnetic circuit. The magnetic flux flows in a path from themagnet104, through the pole piece103,cup102, and top plate111. From there, the flux crosses an outer air gap (not identified in drawing) to the armature106, travel through the armature, and cross an inner air gap to return to themagnet104. The magnetic reluctance depends on a size of aninner air gap113 and/orouter air gap107 between themagnet104 and armature106, and thecup102 and armature106. Theair gap107 is best seen inFIG. 17, between armature106 andmagnet104 in the center ofFIG. 17, and between thecup102 and armature106 at left and right edges of the figure. The top plate111 increases the magnetic surface area between the armature106,cup102 andmagnet104, thus reducing the magnetic reluctance.
• The armature106 is held away from abobbin108 by a spring110, thereby keeping the valve in an open position. Air can flow through thetube112,bobbin108 and out through thecover114. If the coil116 is energized, the armature106 will move toward thebobbin108. Once it reaches thebobbin108, the armature106 will be attracted to themagnet104. The attraction will, most likely, overcome the stiffness of the spring110, thereby holding the valve in a closed position. Agasket material118 can be incorporated to improve an air tight seal of the valve. If a reverse current is applied to the coil116, it will reduce the magnetic field from themagnet104, allowing the spring110 to return the armature106 to the open position.FIG. 16A shows theassembly100 in an open state; shown more closely inFIG. 17 and indicated byarrows115, whereby air is allowed to travel through theassembly100.FIG. 16B shows theassembly100 in a closed state.
• To reduce the current requirements of the coil signal, a small circuit may be incorporated with the valve. The circuit would, most likely, accept a continuous low power logic signal from the hearing instrument electronics, and convert the signal into short pulses required to operate the valve.
EMBODIMENT 2
• In another embodiment, shown inFIG. 18, an assembly200 utilizes abalanced armature receiver202 as the valve. Thereceiver202 has acoil203, anarmature205,magnets207, and ayoke structure209 for transferring magnetic flux which encompasses themagnets207. Thereceiver202 would be modified from traditional designs to enable bistable operation. This may be done via increasing the strength of themagnets207, but may also involve reducing the mechanical stiffness. Thereceiver202 has anextra opening208, which is connected to theopening210 in the rear volume of themicrophone212. Thereceiver202 is designed so that in one position the receiver diaphragm or paddle220 closes the air path between inlet and outlet. One method to do this is to add agasket ring218 inside the cover of the receiver that would touch thepaddle220. Another method would be to have thegasket ring218 seal against the soft film annulus that surrounds thepaddle220. This use of a paddle to open or close the valve should not be limited to a balanced armature application, but may be utilized in other applications such as, for example, those described inFIGS. 16A,16B and17.
EMBODIMENT 3Movement of Ferrofluid
• FIGS. 19 and 20 show the motor portion of a movingfluid valve assembly300. Themotor assembly300 is constructed of twomagnets302 and3 softmagnetic pole pieces304. The field from themagnets302 holds the fluid306 in thegap308 between twoadjacent pole pieces304. Magnetic flux from themagnets302 flows through thepole pieces304, creating a field in the small gap betweentips307 of thepole pieces304.
• When a pulse of current is applied to the coil310, the field in one of thegaps308 will be temporarily reduced, while the field in the opposing gap will be strengthened. A drop offerrofluid306 is attracted to the gaps, and is used to form a seal across the magnetic gap. When current flows through the coil310, the magnetic field weakens in one gap, and strengthens in the other. The fluid312 will move to the gap with the strongest field. When the current is removed, the fluid306 will remain in place. Not shown is a housing. This housing is assembled around the magnetic system to create a path for sound from the rear volume of the microphone through one of the magnetic gaps. When ferrofluid306 is in this gap, no sound may enter the rear of the microphone. This embodiment has an advantage in that thevalve300 may make little sound when in operation. This embodiment has no moving mechanical parts with the exception of the drop of fluid312, so it may be robust against mechanical shock and contamination from dirt or ear wax.
EMBODIMENT 4Moving Magnet
• In an embodiment, shown inFIGS. 21A and 21B, an assembly400 involves a small cylinder or housing402 which is connected to a microphone. An outlet tied to the rear volume of the microphone is connected to thesound inlet403 of the cylinder402. Other shapes may also be used. The cylinder402 is made of non-magnetic material. Inside the cylinder402 is a small magnet404, and outside the cylinder402 is acoil406 of wire. The magnet404 may be a rare-earth magnet, such as Neodymium. An electrical current passing through thecoil406 will force the magnet404 to move from one end of the cylinder402 to the other. At each end of the cylinder402 is aplate408 made of ferrous material, such as steel. Theplate408 is placed so that the magnet404 cannot contact theplate408. This prevents the attractive force betweenplate408 and magnet404 from becoming too great for the force from thecoil406 to overcome. Another alternative would be to let the magnet404 contact theplate408, but manufacture theplate408 to a size whereby the magnetic force of thecoil406 can still move the magnet404. The arrangement of plates, coil, and magnet forms a bistable system. The circumference of the magnet404 is coated with ferrofluid411 to reduce friction between the magnet404 and the case or cylinder402. The magnetic field of the magnet404 assures that the fluid411 will stay near the magnet404, and not leave the cylinder402. When the magnet404 moves towards the sound inlet410, it closes the opening. Asleeve412 may be attached to the end of the magnet404 to help it close or cover the inlet410. Not shown in the diagram is the location of the sound outlet, which is located on the opposite side of the cylinder402, and is connected by a tube to, for instance, the face plate of a hearing aid.
EMBODIMENT 5
• The primary elements are the same as those described in Embodiment 4 (seeFIGS. 21A and 21B). Theassembly500 is similar in construction to the foregoing assembly400 and like elements are identified with a like reference convention beginning from500. However, in thisassembly500, the openings (inlet520aandoutlet520b)520 have been moved to the end of the case502, as seen inFIG. 22. The flat surface of themagnet504 closes off the inlet and outlet openings. The surface of themagnet504 may be covered with a soft gasket material to aid in forming a seal. The steel material may be, for example, washer shaped to enable enough space for the inlet and outlet.
EMBODIMENT 6
• Anassembly600, illustrated inFIG. 23, is provided which is similar in construction as theassembly500 and like elements are identified with a like reference convention beginning from500. However, in this embodiment, a cone-shapedplunger640 may be attached to the end of the magnet604. Slopingedges642 of theplunger640 will improve the air-tight seal when thevalve assembly600 is in a closed position. The positions of theinlet646 and outlet648 may be on either of the sides. In another embodiment (not shown), the positions of theinlet646 and outlet648 may be at the end of thecylinder602. If, in another embodiment (not shown), both theinlet646 and outlet648 are on the sides of thecylinder602, then the end of thecylinder602 may be tapered to seal against theplunger640. The position of the steel washer644 near the inlet and outlet has been moved so that it can be near the magnet604, regardless of the size of theplunger640.
EMBODIMENT 7Moving Magnet
• FIG. 24 shows another moving magnet assembly800. In this design, themagnet802 is attached to afilm804 that acts as a spring to hold the valve assembly800 in an open position. When acoil805 is activated, themagnet802 is forced near thepole piece806. When themagnet802 is close enough, the magnetic attraction will overtake the spring force and hold the valve assembly800 in a closed position. Thefilm804 acts both as a spring, and as a sealing member for the valve assembly800.FIG. 24 shows the valve assembly800 mounted on aflat plate808, which could be, for example, a cup wall of the microphone itself. The surface of themagnet802 may be covered by a soft material to aid in forming a seal.
• The valve assemblies described above can function in place of a second microphone in systems involving matched pairs of microphones. The valve assemblies may remove the need for closely matched pairs of microphones.
• The valve assemblies described above can also be used to open or close a back-vent in a receiver. The low frequency output of a balanced armature receiver can be increased by opening a vent in the devices back-volume. The valve assemblies will allow one receiver to function with the same performance as two different receivers depending on the state of the valve. Areas of application for this feature include hearing-aids and audio earphones where different and distinct low frequency output levels are desired at different times.
• In another embodiment, the present invention generally relates to a semiconductor device which may be constructed with two fixed electrodes separated by an air gap. Between the electrodes is a third free-floating electrode that can be polarized to either of the fixed electrode polarities to electrostatically deflect the free plate/electrode toward either of the fixed electrodes. The electrostatic attraction to either of the fixed electrodes opens or closes either of the acoustic paths through the semiconductor device.
• Turning now to the drawings and referring now toFIG. 25, a cross-sectional view of anacoustic switch mechanism1000 is described. Theswitch1000 has acover1020 havingholes1030 which provide anacoustic path1050. The network ofholes1030, seen inFIG. 26, allow an air path for sound to travel. An acoustic path is a path that allows a contiguous air pathway to allow acoustic wave propagation. For purposes of this specification this acoustic path will be referred to as a frontacoustic path1050. The frontacoustic path1050 allows sound to travel through theacoustic switch mechanism1000 when the switch is open (to be explained in more detail below).
• Thecover1020 may be constructed from, for example, Silicon Nitride, or like materials which produce the desired properties. Thecover1020 may be cylindrical in shape, though other shapes are also contemplated. Thecover1020 may have a diameter or length in a range from 300 um to 1000 um and may have a thickness in a range from 0.5 um to 5 um.Members1040 may extend from asurface1060 of thecover1020. Themembers1040 may have a length in a range from 1.0 um to 10 um.
• Afront electrode1080 may be embedded within thecover1020 via, for example, a semiconductor process such as CVD (Chemical Vapor Deposition.) Theelectrode1080 may be constructed from, for example, Polycrystalline silicon, or like materials which produce the desired properties. Theelectrode1080 may have a thickness in a range from 0.5 um to 1 um and may have a length or diameter in a range from 300 um to 1000 um. Thefront electrode1080 may hold a charge in a range from 1V to 50V. Thefront electrode1080 is a fixed, conductive electrode required to provide the electrostatic attraction or repulsion to a free floating electrode1200 (which will be discussed below). An external polarizing voltage can be electrically applied to theelectrode1080. Themembers1040 may enable a space to be created when the free floatingelectrode1200 is disposed towards thefront electrode1080 as a result of a change in polarity caused by the external voltage.
• Thecover1020 may have anouter perimeter portion1100 which rests upon arear electrode1120. Therear electrode1120 may have a diameter or length in a range from 500 um to 2000 um. Therear electrode1120 may have a thickness in a range from 100 um to 1000 um and may be constructed from, for example, highly doped Silicon, or like materials which produce the desired properties. Therear electrode1120 is a fixed, conductive electrode required to provide the electrostatic attraction or repulsion to the free floatingelectrode1200. An external polarizing voltage can be electrically applied to theelectrode1120. Therear electrode1120, in an embodiment, represents a conductive silicon substrate which overlaps the free floatingelectrode1200 about its outside periphery.
• The free floating electrode, or diaphragm,1200 may be positioned on therear electrode1120. The free floatingelectrode1200 may have a diameter in a range from 300 um to 1000 um. The radius is sufficient to enable aportion1220 of the free floatingelectrode1200 to extend beyond the inner radius of therear electrode1120. The free floatingelectrode1200 is a mechanically actuated plate within theswitch1000. It is a conductive electrode which may have little to no mechanical restriction. An external polarizing voltage can be electrically applied to theelectrode1200. The free floatingelectrode1200 has an external insulating layer to prevent shorting to either of the fixed electrodes. The insulating material may be, for example Silicon dioxide or like materials which produce the desired properties. In another embodiment, an insulating material may be applied to thefront electrode1080 and/or therear electrode1120.
• When theswitch mechanism1000 is actuated, the free floatingelectrode1200 is electrostatically forced to be in physical contact with therear electrode1120. The physical overlap between therear electrode1120 and the free floatingelectrode1200 provides a restriction to the acoustic path through the device formed by holes1310 in the front electrode, around the outside periphery of the free floating electrode, and through the rear electrode thereby closing theacoustic switch1000, as indicated byarrow1500 inFIGS. 28 and 29. A rearacoustic path1240 allows sound to travel through theacoustic switch1000 when the switch is open. Theacoustic path1240 may not exist when theswitch1000 is closed.
• Theacoustic switch mechanism1000 has three terminals to provide application of a voltage to each of the threeelectrodes1080,1120,1200. The source for the voltage may be, for example, a battery or a dedicated integrated circuit. By applying a polarizing voltage to the threeelectrodes1080,1120,1200 in the correct order and polarity to generate electrostatic attraction and repulsion, theswitch mechanism1000 can be electrostatically opened or closed. Provided inFIG. 27 is a table of potential configurations. The “+” sign is defined as a higher potential voltage and the “−” sign is defined as a lower potential voltage level.
• Controlling the polarity of the floatingelectrode1200 allows opening and closing of an acoustic pathway.FIG. 28 illustrates theswitch mechanism1000 in an open position configuration.FIG. 29 illustrates the switch in a closed configuration.FIG. 31 illustrates theswitch mechanism1000 within amicrophone device3000, such as, for example, an omni-directional hearing aid microphone. By closing or opening an acoustic port in a microphone, the user can actively turn the microphone OFF or ON without requiring a power-down and power-up cycle to achieve. With the acoustic switch in an OFF state, sound cannot propagate into the microphone to reach the transducer element, thereby rendering the microphone unable to transduce sound. This allows the user to quickly switch the microphone on and off without incurring, for example, potentially long electrical turn-on and settling times generally associated with electrical power-up cycles in electret microphones.
• By opening or closing an acoustic port in a dual-port directional microphone, the user can switch the functionality from an omni-directional functionality to directional functionality while utilizing only one microphone. A typical omni-directional microphone contains only oneacoustic inlet port3020 which allows sound to impinge upon one (front) side of anacoustic transducer3040. In comparison, a typical directional, or a pressuredifferential microphone2000 is one that contains twoacoustic inlet ports2020,2040, each opening to opposite sides (front and rear) of a single acoustic transducer2010, as illustrated inFIG. 30. One of the differences between an omni microphone and a directional microphone is the presence of a rear acoustic port. By placing an acoustic switch within the microphone, the rear port can be opened or closed electrostatically, switching the microphone functionality from omni to directional.
• In a hearing aid worn in-the-ear, an acoustic switch can be constructed to reside in the vent path, allowing the hearing instrument circuitry to open or close the vent to enable additional features, such as higher gain or reduction in low-frequency background noise. A vent in a hearing aid is a tube which connects the inner ear canal cavity with the outside, ambient environment, used to reduce occlusion and improve patient comfort. In some embodiments, the negative implication of using a vent is that it reduces the available gain of the hearing aid due to a shorter acoustic path between the microphone outside of the ear and the speaker inside the ear canal. By utilizing an acoustic switch, the acoustic vent can be closed in certain situations to allow use of higher gain.
• By utilizing semiconductor technology, smaller functional devices can be created, enabling use in miniature microphones and hearing aids. Electrostatic activation allows acoustic switching with minimal current consumption, since electrostatic devices draw little to no current. This is extremely important in low current devices, such as miniature microphones and hearing aids. A floating electrode design for the switch mechanism allows contact area and open area to be maximized during switch close/open, enabling a good acoustic seal during switch closing and low air resistance in the acoustic path during an open state.
• Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.

Claims (14)

1. A valve for an personal auditory system, the auditory system capable of converting between an acoustic signal and an electrical signal, wherein the auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system, the valve comprising:

a free floating electrode;

a second electrode adjacent to free floating electrode;

wherein an electric signal generated by the second electrode moves the free floating electrode to substantially open or close the acoustic pathway.

2. The valve ofclaim 1 further comprising;

a third electrode, wherein the free floating electrode is positioned between the second electrode and the third electrode, wherein an electric signal generated by the third electrode moves the free floating electrode to substantially open or close the acoustic pathway.

3. The valve ofclaim 1 being positioned within a microphone.

4. A valve for an auditory system, the auditory system capable of converting between an acoustic signal and an electrical signal, wherein the auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system, the valve comprising:

a housing;

a magnetic member located within the housing capable of generating a magnetic force;

an armature adjacent to the magnetic member wherein the magnetic member generates a magnetic force towards the armature;

a coil adjacent to the armature, wherein energizing of the coil attracts or repels the armature to substantially open or close the acoustic pathway.

5. The valve ofclaim 4 further comprising:

a spring member associated with the armature, wherein the spring member applies a force to the armature to open the acoustic pathway.

6. The valve ofclaim 4 further comprising:

a diaphragm coupled to the armature and positioned between the armature and the exterior of the auditory system wherein movement of the diaphragm opens or closes the acoustic pathway.

7. A valve for an auditory system, the auditory system capable of converting between an acoustic signal and an electrical signal, wherein the auditory system has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system, the valve comprising:

a magnetic member;

coil substantially surrounding the magnetic member;

wherein a magnetic field generated by the coil moves the magnetic member to substantially open or close the acoustic pathway.

8. The valve ofclaim 7 wherein the magnetic member is positioned within a housing and the coil surrounds the housing.

9. The valve ofclaim 8 wherein the housing has a port wherein movement of the magnetic member towards the port causes closing of the acoustic pathway.

10. The valve ofclaim 7 further comprising:

a sleeve attached to the magnetic member.

11. A valve for an auditory system, the auditory system capable of converting between an acoustic signal and an electrical signal, wherein the auditory system has a housing and further has an acoustic pathway through which an acoustic signal may travel between a first point exterior to the auditory system and a second point interior to the auditory system, the valve comprising:

a peg element fitted within the housing;

a spring member coupled to the peg element wherein the spring member provides a restoring force to the peg element;

means for actuation of the peg element from a first position to a second position within the housing wherein such actuation substantially closes the acoustic pathway in the second position; and

means for locking the peg element, or releasing the peg element, from the second position.

12. The valve ofclaim 11 wherein the peg has a protruding member from a surface of the peg.

13. The valve ofclaim 12 wherein the means for locking the peg element comprises a cam formed in the housing having a grooved surface sized to receive the protruding member.

14. The valve ofclaim 11 wherein the acoustic pathway includes a port in the housing wherein the peg covers the port when the acoustic pathway is closed.

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