Balanced armature receiver with bi-stable balanced armature

Abstract

A balanced armature receiver is disclosed that includes a housing and an armature assembly within the housing. The armature assembly includes a first armature portion and a second armature portion. The first armature portion and the second armature portion are operated such that the second armature portion is substantially unstable relative to the first armature portion.

Claims

1. A balanced armature receiver comprising: an electric drive coil forming a tunnel with a central longitudinal axis; an armature assembly including a first deflectable armature extending longitudinally through the tunnel; a second deflectable armature extending through the tunnel; and a drive rod coupling the first deflectable armature to an acoustic valve, wherein the first deflectable armature is bi-stable such that the acoustic valve can remain closed or open independent of an energized state of the electric drive coil, and the second deflectable armature is substantially independent from the first deflectable portion based, at least in part, on a difference in one or more mechanical properties of the second deflectable armature relative to the first deflectable armature.

2. The receiver of claim 1, wherein the one or more mechanical properties is rigidity, and the first deflectable armature is less rigid than the second deflectable armature.

3. The receiver of claim 2, wherein an electrical current pulse to the electrical drive coil switches the first deflectable armature between a first bi-stable state and a second bi-stable state.

4. The receiver of claim 1, further comprising: a magnet coupled to the first deflectable armature, wherein the first deflectable portion is substantially independent from the second deflectable armature based, at least in part, on the magnet.

5. The receiver of claim 4, wherein the magnet is a rare earth magnet.

6. The receiver of claim 4, wherein the first deflectable armature is bi-stable such that the acoustic valve remains closed or open independent of an energized state of the electric drive coil based, at least in part, on the magnet.

7. The receiver of claim 1, further comprising: an acoustic pathway through which an acoustic signal travels, wherein a deflection of the first deflectable armature between unstable states opens or closes the acoustic pathway based on opening or closing the acoustic valve.

8. The receiver of claim 1, further comprising: a first pair of permanent magnets forming a first gap between facing surfaces of the first pair of permanent magnets, the first gap being aligned with the central longitudinal axis; a second pair of permanent magnets forming a second gap between facing surfaces of the second pair of permanent magnets, the second gap being aligned with the central longitudinal axis and adjacent to the first gap, wherein the first deflectable portion of the first armature is substantially independent based, at least in part, on a difference in magnetic strength between the first pair of permanent magnets and the second pair of permanent magnets.

9. The receiver of claim 8, wherein the second pair of permanent magnets are rare earth magnets.

10. The receiver of claim 9, wherein the electric drive coil is coupled directly to the second deflectable armature.

11. A method of detecting a state of an acoustic valve coupled to a balanced armature within a receiver, the method comprising: determining an impedance curve as a function of frequency through the balanced armature collapsed against one of two of permanent magnets, wherein magnetic hysteresis curves of the two permanent magnets vary; comparing the determined impedance to known impedances for the balanced armature collapsed against each of the two permanent magnets; and determining a state of the acoustic valve based on the comparison, wherein the two permanent magnets have different magnetic hysteresis curves.

12. The method of claim 11, further comprising: energizing an electric coil of the balanced armature to change the state of the acoustic valve based on determining that the state is off.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described in further details with reference to the accompanying figures, wherein:

(2) FIG. 1A shows a perspective view of components of a balanced armature receiver, in accord with aspects of the present disclosure;

(3) FIG. 1B shows an additional perspective view of components of a balanced armature receiver, including travel distances of armature portions, in accord with aspects of the present disclosure;

(4) FIG. 1C shows an unstable state of an armature portion of a balanced armature receiver connected to an acoustic valve, in accord with aspects of the present disclosure;

(5) FIG. 1D shows another unstable state of the armature portion of a balanced armature receiver of FIG. 1C, in accord with aspects of the present disclosure;

(6) FIG. 2 shows a perspective view of a balanced armature receiver with a shared electric drive coil and magnet stack, in accord with aspects of the present disclosure;

(7) FIG. 3A shows a front perspective view of a balanced armature receiver with a shared electric drive coil and magnet stack, and an additional electric drive coil, in accord with aspects of the present disclosure;

(8) FIG. 3B shows a back perspective view of the balanced armature receiver of FIG. 3A, in accord with aspects of the present disclosure;

(9) FIG. 4 shows a perspective view of a balanced armature receiver without a shared magnet stack, and a permanent magnet on an armature portion, in accord with aspects of the present disclosure;

(10) FIG. 5 shows a perspective view of a balanced armature receiver with a dual stack of magnets, in accord with aspects of the present disclosure;

(11) FIG. 6A shows a front perspective view of a balanced armature receiver with separate magnetic housings, in accord with aspects of the present disclosure;

(12) FIG. 6B shows a back perspective view of the balanced armature receiver of FIG. 6A, in accord with aspects of the present disclosure;

(13) FIG. 6C shows a modified version of the balanced armature receiver of FIGS. 6A and 6B, in accord with aspects of the present disclosure;

(14) FIG. 6D shows another modified version of the balanced armature receiver of FIGS. 6A and 6B, in accord with aspects of the present disclosure;

(15) FIG. 6E shows an alternative arrangement of the balanced armature receiver of FIGS. 6A and 6B, in accord with aspects of the present disclosure;

(16) FIG. 7 shows a perspective view of a balanced armature receiver based on a generally E-shaped armature, in accord with aspects of the present disclosure;

(17) FIG. 8 shows a perspective view of a balanced armature receiver based on a generally E-shaped armature with three electric drive coils, in accord with aspects of the present disclosure;

(18) FIG. 9A shows a perspective view of a balanced armature receiver based on a generally E-shaped armature with two magnet stacks, in accord with aspects of the present disclosure;

(19) FIG. 9B shows a perspective view of a modified version of the balanced armature receiver of FIG. 9A, in accord with aspects of the present disclosure;

(20) FIG. 9C shows a perspective view of another modified version of the balanced armature receiver of FIG. 9A, in accord with aspects of the present disclosure;

(21) FIG. 10A shows a perspective view of the exterior of the housing of a balanced armature receiver, in accord with aspects of the present disclosure;

(22) FIG. 10B shows a perspective view of the internal components of the balanced armature receiver of FIG. 10A, with an acoustic valve in an open position, in accord with aspects of the present disclosure;

(23) FIG. 10C shows a perspective view of the internal components of the balanced armature receiver of FIG. 10A, with the acoustic valve in the closed position, in accord with aspects of the present disclosure;

(24) FIG. 11A shows the potential energy versus elongation of a membrane-based flip-flop valve, in accord with aspects of the present disclosure;

(25) FIG. 11B shows the membrane-based flip-flop valve of FIG. 11A in a first state, in accord with aspects of the present disclosure;

(26) FIG. 11C shows the membrane-based flip-flop valve of FIG. 11A in a second state, in accord with aspects of the present disclosure;

(27) FIG. 12 shows an active valve formed independent of a balanced armature receiver, in accord with aspects of the present disclosure;

(28) FIG. 13A shows the active valve of FIG. 12 in the form of an acoustic valve in an open position, in accord with aspects of the present disclosure;

(29) FIG. 13B shows the active valve of FIG. 12 in the form of an acoustic valve in a closed position, in accord with aspects of the present disclosure;

(30) FIG. 14 shows a relay based on the active control of a balanced armature, in accord with aspects of the present disclosure;

(31) FIG. 15A shows a flow diagram for using a balanced armature receiver with an integrated acoustic valve, in accord with aspects of the present disclosure; and

(32) FIG. 15B shows a flow diagram for detecting a state of an acoustic valve coupled to a balanced armature within a balanced armature receiver, in accord with aspects of the present disclosure.

(33) While the apparatuses and methods discussed herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the description is not intended to be limited to the particular forms disclosed. Rather, the description is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

(34) While the apparatuses discussed in the present disclosure are susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the apparatuses with the understanding that the present disclosure is to be considered as an exemplification of the principles of the apparatuses and is not intended to limit the broad aspect of the apparatuses to the embodiments illustrated. For purposes of the present detailed description, the singular includes the plural and vice versa (unless specifically disclaimed); the word “or” shall be both conjunctive and disjunctive; the word “all” means “any and all”; the word “any” means “any and all”; and the word “including” means “including without limitation.” Additionally, the singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise.

(35) FIG. 1 shows a perspective view of components of a balanced armature receiver 100, in accord with aspects of the present disclosure. The balanced armature receiver 100 includes a housing 102. The housing 102 can be various types of housings for acoustic devices. For example, the housing 102 can limit or reduce radio frequency interference, can provide shielding for the internal components, and can be formed of a high-strength material, such as high-strength aluminum or steel. Depending on the application of the housing 102, the housing 102 can be made with biocompatible materials, such housings for hearing aids and personal listening devices.

(36) Within the housing 102 is a balanced armature assembly 104. The balanced armature assembly 104 includes an armature portion 106a and an armature portion 108a. The armature portions 106a, 108a can be portions of one or more generally U-shaped, generally E-shaped, or substantially flat armatures within of armature assembly 104. Moreover, the shape of the armatures of which the armature portions 106a, 108a are a part of may vary between each other. By way of example, and without limitation, the armature portion 106a may be of a generally U-shaped armature, and the armature portion 108a may be of a generally U-shaped, a generally E-shaped, or a substantially flat armature. Although shown as being separate, the armature portions 106a, 108a can be portions of the same armature of the armature assembly 104, or can be portions of two separate armatures of the armature assembly 104. In the configuration of two separate armatures within the armature assembly 104, the two separate armatures are mechanically, magnetically, and/or electrically associated and within the same immediate housing (e.g., housing 102) to constitute the single armature assembly 104.

(37) The balanced armature receiver 100 and the armature portion 106a are configured mechanically, magnetically, or a combination thereof such that the armature portion 106a is stable in a balanced arrangement during operation of the balanced armature receiver 100. As discussed in detail below, the armature portion 106a is connected to a diaphragm (not shown) to generate acoustic signals of the balanced armature receiver 100.

(38) The balanced armature receiver 100 and the armature portion 108a are configured mechanically, magnetically, or a combination thereof such that the armature portion 108a is unstable and in one of two bi-stable states in an unbalanced arrangement during operation of the balanced armature receiver 100. Thus, although the armature portion 108a is configured, in part, according to a balanced armature design, the armature portion 108a is configured to be unstable and within one of two bi-stable states to control one or more parts, and/or perform one or more functions, within the balanced armature receiver 100. Accordingly, the armature portion 108a collapses toward an upper or lower portion of the magnetic housing (not shown) and/or magnet stack (not shown) during operation, as discussed in greater detail below. Despite electrical current pulses sent to one or more electric drive coils (discussed below) associated with the armature portion 108a, the armature portion 108a remains unstable and in a bi-stable state (i.e., collapsed toward an upper or lower portion of the magnetic housing and/or magnet stack). Thus, magnetic flux generated by the electrical current pulses to the electric drive coils is insufficient to move the armature portion 108a from the current bi-stable state. However, in embodiments in which the armature portion 108a is associated with the same electric drive coils as the armature portion 106a, electrical current pulses can be sent to the same electric drive coils to drive the armature portion 106a to generate the acoustic signals while being insufficient to switch the armature portion 108a from the bi-stable state. Alternatively, different electric drive coils can be associated with the armature portions 106a, 108a to drive the armature portions 106a, 108a substantially independently, although the armature portions 106a, 108a are part of the same armature assembly 104 within the housing 102 of the balanced armature receiver 100.

(39) Based on the armature portion 108a collapsing to an upper or lower portion, the armature portion 108a can be connected to one or more parts within the balanced armature receiver 100 to perform one or more functions substantially independently over control of the diaphragm by the armature portion 106a. By way of example, and without limitation, the armature portion 108a can be connected to an acoustic valve within the balanced armature receiver 100 to either close or open the acoustic valve. By closing or opening the acoustic valve, operation of the armature portion 108a switches the balanced armature receiver 100 between an open fitting and a closed fitting. Thus, the same armature assembly 104 can be used to both generate acoustic signals and to change the open/closed fitting of the balanced armature receiver 100.

(40) FIG. 1B shows one arrangement of the armature portions 106a, 108a within the armature assembly 104. Based on electrical current pulses sent through electric drive coils associated with the armature portions 106a, 108a, the armature portions 106a, 108a travel up and down. For example, the armature portion 108a travels the distance L.sub.1 and the armature portion 106a travels the distance L.sub.2 during operation of the balanced armature receiver 100. Based on one or more mechanical, electrical, and/or magnetic properties of the armature portion 106a relative to the armature portion 108a, or elements of the balanced armature receiver 100 for the armature portion 106a relative to the armature portion 108a (discussed in greater detail below), the armature portion 108a may be operated to remain unstable and in one bi-stable state (e.g., between the upper and lower extremes of the travel length L.sub.1), while the armature portion 106a remains in a stable, balanced state between the upper and lower extremes of the travel length L.sub.2. Accordingly, the armature portion 106a can drive a diaphragm to generate acoustic signals while the armature portion 108a controls another element or function within the balanced armature receiver 100.

(41) Referring to FIGS. 1C and 1D, the armature portion 108a can be a portion of a generally U-shaped armature 108 that is connected to a drive rod 110. Opposite the armature portion 108a, the drive rod 110 is connected to a valve 112, such as an acoustic valve. The valve 112 may be configured to mate within an aperture 114. The aperture 114 may be within an acoustic pathway within the balanced armature receiver 100. Closing or opening the aperture 114 closes or opens the acoustic pathway and, therefore, switches the balanced armature receiver 100 between an open fitting and a closed fitting. According to some embodiments, the aperture is 0.5 to 10 millimeters squared (mm.sup.2) to provide for an acoustic pathway that prevents, or at least reduces, occlusion.

(42) FIG. 1C shows the armature portion 108a in a bi-stable state extending towards the lower extreme of the travel length L.sub.1. Based on the armature portion 108a being connected to the valve 112 through the drive rod 110, the valve 112 is in a substantially open position. FIG. 1D shows the armature portion 108a in a bi-stable state extending towards the upper extreme of the travel length L.sub.1. Based on the armature portion 108a being connected to the valve 112 through the drive rod 110, the valve 112 is in a substantially closed position. Based on the armature portion 108a being unstable and controlled in one of two bi-stable states, the armature portion 108a can control the position of the valve 112 and, therefore, the open or closed state of the aperture 114 to control whether the acoustic pathway is in a closed or open state. Moreover, because the armature portion 108a is part of the armature assembly 104, the armature portion 106a can continue controlling the diaphragm to generate acoustic signals substantially independent of the armature portion 108a while reducing the overall size of the balanced armature receiver with an active acoustic vent.

(43) FIG. 2 shows a perspective view of a balanced armature receiver 200 with a shared electric drive coil and magnet stack, in accord with aspects of the present disclosure. Similar to the balanced armature receiver 100, the balanced armature receiver 200 includes a housing 202, which is as described with respect to the housing 102. Within the housing 202 is an armature assembly 204. According to the specific arrangement of the balanced armature receiver 200, the armature assembly 204 includes armature portions 206a, 208a. The armature portions 206a, 208a are portions of two separate armatures of the armature assembly 204. Specifically, the armature portion 206a is the deflectable portion of the armature 206, and the armature portion 208a is the deflectable portion of the armature 208. However, alternatively, the armature portions 206a, 208b can be portions of the same armature. As shown, the armatures 206, 208 are generally U-shaped armatures, which further include fixed portions 206b and 208b.

(44) The balanced armature receiver 200 further includes a magnetic housing 210. The distal ends of the armature portions 206a, 208a extend through the magnetic housing 210. The magnetic housing 210 includes a pair of magnets 212. Opposing surfaces of the pair of magnets 212 form a gap 214 through which the distal ends of the armature portions 206a, 208a extend.

(45) The balanced armature receiver 200 further includes an electric drive coil 216. The electric drive coil 216 may be any conventional electric drive coil used within the field of balanced armatures. The electric drive coil 216 is formed of a winding of an electrically conductive material, such as copper. The diameter of the windings may be large enough to prevent or limit the effects of corrosion from the electric drive coils being in, for example, a corrosive environment, such as a biological environment (e.g., a user's ear). Alternatively, or in addition, the windings may be coated with a protective material, such as a parylene coating. The electric drive coil 216 forms a tunnel through which the armature portions 206a, 208a extend prior to extending through the gap 212.

(46) The armature portion 206a includes a drive rod 218 that connects the armature portion 206a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 208a includes a drive rod (not shown) that connects the armature portion 208a to an acoustic valve (not shown), discussed in greater detail below.

(47) In operation, an electric current passes through the electric drive coil 216, which generates a magnetic field and magnetically energizes the armature portions 206a, 208a. Upon becoming magnetically energized, the armature portions 206a, 208a are magnetically attracted to one magnet of the pair of magnets 212. Based on the armature portions 206a, 208a sharing the electric drive coil 216 and the pair of permanent magnets 212, one or more mechanical and/or magnetic properties of the armature portion 208a is varied relative to the armature portion 206a so that the armature portion 208a is unstable and collapses a bi-stable state. The mechanical and magnetic properties may include, for example, the rigidity and magnetic permeability of the armature portions 206a, 208a relative to each other. Accordingly, during operation, the armature portion 208a is unstable relative to the armature portion 206a and collapses to a bi-stable state. The armature portion 208a collapses toward the upper or lower magnet of the pair of permanent magnets 212 and remains in the bi-stable state while the electric drive coil 216 drives the armature portion 206a to generate the acoustic signals.

(48) FIG. 3 shows a perspective view of a balanced armature receiver 300 with a shared electric drive coil and magnet stack, and an additional electric drive coil, in accord with aspects of the present disclosure. The balanced armature receiver 300 is similar to the balanced armature receiver 200 of FIG. 2. That is, the balanced armature receiver 300 includes a housing 302, which is as described with respect to the housing 102. Within the housing 302 is an armature assembly 304. According to the specific arrangement of the balanced armature receiver 300, the armature assembly 304 includes armature portions 306a, 308a. The armature portions 306a, 308a are portions of two separate armatures of the armature assembly 304. Specifically, the armature portion 306a is the deflectable portion of the armature 306, and the armature portion 308a is the deflectable portion of the armature 308. As shown, the armatures 306, 308 are generally U-shaped armatures, which further include fixed portions 306b and 308b. The fixed portions 306b, 308b are coupled to the housing 302 to fix the armature assembly 304 within the balanced armature receiver 300.

(49) The balanced armature receiver 300 further includes a magnetic housing 310. The distal ends of the armature portions 306a, 308a extend through the magnetic housing 310. The magnetic housing 310 includes a pair of magnets 312. Opposing surfaces of the pair of magnets 312 form a gap 314 through which the distal ends of the armature portions 306a, 308a extend.

(50) The balanced armature receiver 300 further includes an electric drive coil 316. The electric drive coil 316 may be any conventional electric drive coil used within the field of balanced armatures. The electric drive coil 316 is formed of a winding of an electrically conductive material, such as copper. The diameter of the windings may be large enough to prevent or limit the effects of corrosion from the electric drive coils being in, for example, a corrosive environment, such as a biological environment (e.g., a user's ear). Alternatively, or in addition, the windings may be coated with a protective material, such as a parylene coating. The electric drive coil 316 forms a tunnel through which the armature portions 306a, 308a extend prior to extending through the gap 312.

(51) The armature portion 306a includes a drive rod 318 that connects the armature portion 306a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 308a includes a drive rod (not shown) that connects the armature portion 308a to an acoustic valve (not shown), discussed in greater detail below.

(52) The balanced armature receiver 300 further includes a drive coil 320. The electric drive coil 320 surrounds the fixed portion 308b of the armature 308. The electric drive coil 320 can be directly coupled to the fixed portion 308b of the armature 308. Alternatively, the electric drive coil 320 can be indirectly coupled to the fixed portion 308b of the armature 308, such as through both being coupled to the housing 302. The electric drive coil 320 can be formed and attached to the armature 308, such as being slid around the fixed portion 308b of the armature 308 after being formed. Alternatively, the electric drive coil 320 can be formed around the fixed portion 308. For example, the windings that form the electric drive coil 320 can be wound directly around the fixed armature 308b.

(53) Although shown as surrounding the fixed portion 308b of the armature 308, alternatively, the electric drive coil 320 can surround the armature portion 308a, which is the moving portion of the armature 308a. In the context of balanced armature designs, typically the mass of the armature portion 308a is minimized to reduce the energy required to move the armature portion 308a. However, because the armature portion 308a is used to control the position of an acoustic valve, the mass of the armature portion 308a can be increased without negatively impacting its function, because the functionality of the armature portion 308a is to control the position of an acoustic valve.

(54) In operation, an electric current passes through the electric drive coil 316, which generates a magnetic field and magnetically energizes the armature portions 306a, 308a. Upon becoming magnetically energized, the armature portions 306a, 308a are magnetically attracted to one magnet of the pair of magnets 312. Based on the armature portions 306a, 308a sharing the electric drive coil 316 and the pair of permanent magnets 312, one or more mechanical and/or magnetic properties of the armature portion 308a is varied relative to the armature portion 306a so that the armature portion 308a is unstable and collapses to a bi-stable state. The mechanical and magnetic properties may include, for example, the rigidity and magnetic permeability of the armature portions 306a, 308a relative to each other. Accordingly, during operation, the armature portion 308a is unstable relative to the armature portion 306a and collapses to a bi-stable state. The armature portion 308a collapses toward the upper or lower magnet of the pair of permanent magnets 312 and remains in the bi-stable state while the electric drive coil 316 drives the armature portion 306a to generate the acoustic signals. In addition, the presence of the electric drive coil 320 allows the armature portion 308a to be driven substantially independently of the electric drive coil 316. The electric drive coil 320 allows the bi-stable state of the armature portion 308a to be changed independently from an electric current pulse to the electric drive coil 316, which may otherwise detract from the acoustic signals generated by the armature portion 306a.

(55) FIG. 4 shows a perspective view of a balanced armature receiver 400 without a shared magnet stack, but with a permanent magnet on an armature portion, in accord with aspects of the present disclosure. Like the balanced armature receivers 200, 300, and as discussed above with respect to FIG. 1, the balanced armature receiver 400 includes a housing; though not shown for illustrative convenience. Within the housing is an armature assembly 404. According to the specific arrangement of the balanced armature receiver 400, the armature assembly 404 includes armature portions 406a, 408a. The armature portions 406a, 408a are portions of two separate armatures of the armature assembly 404. Specifically, the armature portion 406a is the deflectable portion of the armature 406, and the armature portion 408a is the deflectable portion of the armature 408. As shown, the armatures 406, 408 are generally U-shaped armatures, which further include fixed portions 406b and 408b. The fixed portions 406b, 408b are coupled to the housing 402 to fix the armature assembly 404 within the balanced armature receiver 400.

(56) The balanced armature receiver 400 further includes a magnetic housing 410. The distal ends of the armature portions 406a, 408a extend through the magnetic housing 410. The magnetic housing 410 includes a pair of magnets 412. Opposing surfaces of the pair of magnets 412 form a gap 414 through which the distal end of the armature portion 406a extends. Thus, unlike the balanced armature receivers 200, 300, the armature portion 408a does not extend through the gap 414 between the pair of permanent magnets 412. Instead, a permanent magnet 422 is directly coupled to the distal end of the armature portion 408a. The permanent magnet 422 can be any type of magnet that provides enough magnetic flux to keep the armature portion 408a unstable and in a bi-stable state, collapsed toward the upper or lower portion of the magnetic housing 410. According to one embodiment, the permanent magnet 422 can be a rare earth magnet to, for example, reduce the size of the permanent magnet relative to a non-rare earth magnet.

(57) Similar to the discussion above, in the context of balanced armature designs, typically the mass of the armature portion 408a would be minimized to reduce the energy required to move the armature portion 408a. Thus, one would typically not add mass to the armature portion 408a by adding the permanent magnet 422. However, because the armature portion 408a is used to control the position of an acoustic valve, the mass of the armature portion 408a can be increased without prohibiting the functionality of the armature portion 408a controlling acoustic valve.

(58) The balanced armature receiver 400 further includes an electric drive coil 416. The electric drive coil 416 may be any conventional electric drive coil used within the field of balanced armatures. The electric drive coil 416 is formed of a winding of an electrically conductive material, such as copper. The diameter of the windings may be large enough to prevent or limit the effects of corrosion from the electric drive coils being in, for example, a corrosive environment, such as a biological environment (e.g., a user's ear). Alternatively, or in addition, the windings may be coated with a protective material, such as a parylene coating. The electric drive coil 416 forms a tunnel through which the armature portions 406a, 408a extend prior to extending through the gap 412.

(59) The armature portion 406a includes a drive rod 418 that connects the armature portion 406a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 408a includes a drive rod (not shown) that connects the armature portion 408a to an acoustic valve (not shown), discussed in greater detail below.

(60) The balanced armature receiver 400 further includes a drive coil 420. The electric drive coil 420 surrounds the fixed portion 408b of the armature 408. Similar to the electric drive coil 320, the electric drive coil 420 can be directly coupled to the fixed portion 408b of the armature 408. Alternatively, the electric drive coil 420 can be indirectly coupled to the fixed portion 408b of the armature 408, such as through both being coupled to the housing 402. The electric drive coil 420 can be formed and attached to the armature 408, such as being slid around the fixed portion 408b of the armature 408 after being formed. Alternatively, the electric drive coil 420 can be formed around the fixed portion 408. For example, the windings that form the electric drive coil 420 can be wound directly around the fixed armature 408b. Although shown as surrounding the fixed portion 408b of the armature 408, alternatively, the electric drive coil 420 can surround the armature portion 408a, which is the moving portion of the armature 408a.

(61) In operation, an electric current passes through the electric drive coil 416, which generates a magnetic field and magnetically energizes the armature portions 406a, 408a. Upon becoming magnetically energized, the armature portions 406a, 408a are magnetically attracted to one magnet of the pair of magnets 412 or to the corresponding portion of the magnetic housing 410. Based on the armature portions 406a, 408a sharing the electric drive coil 416, one or more mechanical and/or magnetic properties of the armature portion 408a is varied relative to the armature portion 406a so that the armature portion 308a is unstable and collapses to a bi-stable state. For this arrangement, the variation is, in part, the presence of the permanent magnet 422 coupled to the armature portion 408a. Accordingly, the armature portion 408a collapses toward the upper or lower portion of the magnetic housing 410 in the bi-stable state and remains in the bi-stable state while the electric drive coil 416 drives the armature portion 406a to generate the acoustic signals. In addition, the presence of the electric drive coil 420 allows the armature portion 408a to be driven substantially independently of the electric drive coil 416. The electric drive coil 420 allows the bi-stable state of the armature portion 408a to be changed independent from an electric current pulse to the electric drive coil 416, which may otherwise detract from the acoustic signals generated by the armature portion 406a.

(62) FIG. 5 shows a perspective view of a balanced armature receiver 500 with a dual stack of magnets, in accord with aspects of the present disclosure. Like the balanced armature receivers 200-400, and as discussed above with respect to FIG. 1, the balanced armature receiver 500 includes a housing; though not shown for illustrative convenience. Within the housing is an armature assembly 504. According to the specific arrangement of the balanced armature receiver 500, the armature assembly 504 includes armature portions 506a, 508a. The armature portions 506a, portion 508a are portions of two separate armatures of the armature assembly 504. Specifically, the armature portion 506a is the deflectable portion of the armature 506, and the armature portion 508a is the deflectable portion of the armature 508. As shown, the armatures 506, 508 are generally U-shaped armatures, which further include fixed portions 506b and 508b. The fixed portions 506b, 508b are coupled to the housing 502 to fix the armature assembly 504 within the balanced armature receiver 500.

(63) The balanced armature receiver 500 further includes a magnetic housing 510. The distal ends of the armature portions 506a, 508a extend through the magnetic housing 510. The magnetic housing 510 includes a pair of magnets 512. Opposing surfaces of the pair of magnets 512 form a gap 514 through which the distal end of the armature portion 506a extends. Thus, similar to the balanced armature receiver 400, the armature portion 508a does not extend through the gap 514 between the pair of permanent magnets 512. Instead, a pair magnets 524 is directly coupled to the distal end of the armature portion 508a, with one magnet of the pair of magnets 524 coupled to each side of the armature portion 508a. The permanent magnets 524 can be any type of magnet that provides enough magnetic flux to keep the armature portion 508a unstable and in a bi-stable state, collapsed toward the upper or lower portion of the magnetic housing 510. According to one embodiment, the permanent magnets 524 can be a rare earth magnets to, for example, reduce the size of the permanent magnets relative to a non-rare earth magnet.

(64) Similar to the discussion above, in the context of balanced armature designs, typically the mass of the armature portion 508a would be minimized to reduce the energy required to move the armature portion 508a. Thus, one would typically not add mass to the armature portion 508a by adding the pair of permanent magnets 524. However, because the armature portion 508a is used to control the position of an acoustic valve, the mass of the armature portion 508a can be increased without prohibiting the functionality of the armature portion 508a controlling acoustic valve.

(65) The balanced armature receiver 500 further includes an electric drive coil 516. The electric drive coil 516 may be any conventional electric drive coil used within the field of balanced armatures. The electric drive coil 516 is formed of a winding of an electrically conductive material, such as copper. The diameter of the windings may be large enough to prevent or limit the effects of corrosion from the electric drive coils being in, for example, a corrosive environment, such as a biological environment (e.g., a user's ear). Alternatively, or in addition, the windings may be coated with a protective material, such as a parylene coating. The electric drive coil 516 forms a tunnel through which the armature portions 506a, 508a extend prior to extending through the gap 514.

(66) The armature portion 506a includes a drive rod 518 that connects the armature portion 506a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 508a includes a drive rod (not shown) that connects the armature portion 508a to an acoustic valve (not shown), discussed in greater detail below.

(67) The balanced armature receiver 500 further includes a drive coil 520. The electric drive coil 520 surrounds the fixed portion 508b of the armature 508. Similar to the electric drive coils 320, 420, the electric drive coil 520 can be directly coupled to the fixed portion 508b of the armature 508. Alternatively, the electric drive coil 520 can be indirectly coupled to the fixed portion 508b of the armature 508, such as through both being coupled to the housing 502. The electric drive coil 520 can be formed and attached to the armature 508, such as being slid around the fixed portion 508b of the armature 508 after being formed. Alternatively, the electric drive coil 520 can be formed around the fixed portion 508. For example, the windings that form the electric drive coil 520 can be wound directly around the fixed armature 508b. Although shown as surrounding the fixed portion 508b of the armature 508, alternatively, the electric drive coil 520 can surround the armature portion 508a, which is the moving portion of the armature 408a.

(68) In operation, an electric current passes through the electric drive coil 516, which generates a magnetic field and magnetically energizes the armature portions 506a, 508a. Upon becoming magnetically energized, the armature portions 506a, 508a are magnetically attracted to one magnet of the pair of magnets 512 of the upper or lower portion of the magnetic housing 510. Based on the armature portions 506a, 508a sharing the electric drive coil 516, one or more mechanical and/or magnetic properties of the armature portion 508a is varied relative to the armature portion 506a. For this arrangement, the variation is, in part, the presence of the pair of permanent magnets 524 coupled to the armature portion 508a. Accordingly, the armature portion 508a collapses toward the upper or lower portion of the magnetic housing 510 in the bi-stable state and remains in the bi-stable state while the electric drive coil 516 drives the armature portion 506a to generate the acoustic signals. In addition, the presence of the electric drive coil 520 allows the armature portion 508a to be driven substantially independently of the electric drive coil 516. For example, the electric drive coil 520 allows the bi-stable state of the armature portion 508a to be changed independent from an electric current pulse from the electric drive coil 516, which may otherwise detract from the acoustic signals generated by the armature portion 506a.

(69) FIGS. 6A and 6B show perspective views from different perspectives of a balanced armature receiver 600 with separate magnetic housings, in accord with aspects of the present disclosure. Like the balanced armature receivers 200-500, and as discussed above with respect to FIG. 1, the balanced armature receiver 600 includes a housing; though not shown for illustrative convenience. Within the housing is an armature assembly 604. According to the specific arrangement of the balanced armature receiver 600, the armature assembly 604 includes armature portions 606a, 608a. The armature portions 606a, 608a are portions of two separate armatures of the armature assembly 604. Specifically, the armature portion 606a is the deflectable portion of the armature 606, and the armature portion 608a is the deflectable portion of the armature 608. As shown, the armatures 606, 608 are generally U-shaped armatures, which further include fixed portions 606b and 608b. The fixed portions 506b, 508b are coupled to the housing 502 to fix the armature assembly 504 within the balanced armature receiver 500.

(70) The balanced armature receiver 600 further includes a magnetic housing 610 and a magnetic housing 626. The distal end of the armature portion 606a extends through the magnetic housing 610, and the distal end of the armature portion 608a extends through the magnetic housing 626. The magnetic housing 610 includes a pair of magnets 612. Opposing surfaces of the pair of magnets 612 form a gap 614 through which the distal end of the armature portion 506a extends. The magnetic housing 626 includes a pair of magnets 628. Opposing surfaces of the pair of magnets 628 form a gap 630 through which the distal end of the armature portion 608a extends. Thus, similar to the balanced armature receivers 400 and 500, the armature portion 608a does not extend through the gap 614 between the pair of permanent magnets 612. Instead, however, the armature portion 608a extends through the gap 630 between the pair of permanent magnets 628. The permanent magnets 628 can be any type of magnet that provides enough magnetic flux to keep the armature portion 608a unstable and collapsed toward the upper or lower portion of the magnetic housing 626. According to one embodiment, the permanent magnets 628 can be a rare earth magnet to, for example, reduce the size of the permanent magnets relative to a non-rare earth magnet.

(71) The balanced armature receiver 600 optionally can include a pair of spacers 632. Each spacer 632 is coupled to a separate permanent magnet 628. The pair of spacers 632 limit the travel distance of the armature portion 608a required between unstable states, e.g., collapsed towards the upper or lower portion of the magnetic housing 626. Spacers of different sizes (e.g., lengths) can be placed on the permanent magnets 628 to control the travel distance of the armature portion 608a. Moreover, placement of the spacers 632 also reduces the magnetic force on the armature portion 608a from the permanent magnets 628 to reduce or control the restoring force or magnetic force required to actuate the armature portion 608a to the opposite bi-stable state. The spacers 632 can be formed of various substantially non-magnetic material(s), such as, for example, plastic, rubber, wood, brass, gold, silver, and the like, or combinations thereof.

(72) FIG. 6C shows a perspective view of a balanced armature receiver 600′, which is a modified version of the balanced armature receiver 600 of FIGS. 6A and 6B, in accord with aspects of the present disclosure. The elements of the balanced armature receiver 600′ are the same as the balanced armature receiver 600, except for the magnetic housing 610′. To conserve space, the left side of the magnetic housing 610′ is removed and the magnetic housing 610′ is coupled to the right side of the magnetic housing 626. Alternatively, the magnetic housing 610′ and the magnetic housing 626 can be formed as a solid, integral piece to form a single magnetic housing. By way of example, and without limitation, the single magnetic housing can be formed by metal injection molding.

(73) FIG. 6D shows a perspective view of a balanced armature receiver 600″, which is a modified version of the balanced armature receivers 600 and 600′ of FIGS. 6A-6C, in accord with aspects of the present disclosure. The elements of the balanced armature receiver 600″ are the same as the balanced armature receivers 600 and 600′, except for the magnetic housings 610″, 626″. The right side of the magnetic housing 626 of the balanced armature receivers 600 and 600′ is removed and the resulting magnetic housing 626″ is coupled to the left side of the magnetic housing 610″. Alternatively, the magnetic housing 610″ and the magnetic housing 626″ can be formed as a solid, integral piece to form a single magnetic housing. As described above, the single magnetic housing can be formed by metal injection molding.

(74) FIG. 6E shows an alternative arrangement of the balanced armature receiver 600, in accord with aspects of the present concepts. Specifically, the components associated with the armature portion 608a, such as the magnetic housing 626, etc. can be oriented differently than the components associated with the armature portion 606a, such as the magnetic housing 610, etc. By way of example, and without limitation, the armature portion 608a can be rotated 90 degrees relative to the orientation of the armature portion 606a. Similarly, the travel direction of the armature portion 608a can be oriented differently than the travel direction of the armature portion 606a. Further, the travel direction and/or direction of movement required to actuate the acoustic valve can vary in any embodiment disclosed herein, such as being horizontal rather than vertical.

(75) In operation, the presence of the electric drive coil 620 allows the armature portion 608a to be driven substantially independent of the electric drive coil 616. For example, the electric drive coil 620 allows the bi-stable state of the armature portion 608a to be changed independent from an electric current pulse from the electric drive coil 616 to generate the acoustic signals. Further, the presence of the pair of permanent magnets 624 coupled to the armature portion 608a allows the armature portion 608a to be unstable and in a bi-stable state relative to the armature portion 606a. In addition, one or more mechanical and/or magnetic properties of the armature portion 608a can be varied relative to the armature portion 606a. For example, although the armature portion 608a is substantially controlled by the electric drive coil 620, the rigidity of the armature portion 608a may be less than the rigidity of the armature portion 606a.

(76) FIG. 7 shows a perspective view of a balanced armature receiver 700 based on a generally E-shaped armature, in accord with aspects of the present disclosure. Like the balanced armature receivers 200-600″, and as discussed above with respect to FIG. 1, the balanced armature receiver 700 includes a housing; though not shown for illustrative convenience. Within the housing is an armature assembly 704. According to the specific arrangement of the balanced armature receiver 700, the armature assembly 704 is a modified generally E-shaped armature. Instead of having one armature portion extending from the center, the armature assembly 704 has armature portions 706a, 708a extending from the center. Specifically, the armature portion 706a is a deflectable portion of the armature assembly 704, and the armature portion 708a is a deflectable portion of the armature assembly 704. The armature assembly 704 further includes fixed portions 706b, 708b. The fixed portions 706b, 708b are coupled to the housing to fix the armature assembly 704 within the balanced armature receiver 700.

(77) The balanced armature receiver 700 further includes a magnetic housing 710. The distal ends of the armature portions 706a, 708a extend through the magnetic housing 710. The magnetic housing 710 includes a pair of permanent magnets 712. Opposing surfaces of the pair of permanent magnets 712 form a gap 714 through which the distal ends of the armature portions 706a, 708a extend.

(78) The balanced armature receiver 700 further includes an electric drive coil 716. The electric drive coil 716 may be any conventional electric drive coil used within the field of balanced armatures. The electric drive coil 716 is formed of a winding of an electrically conductive material, such as copper. The diameter of the windings may be large enough to prevent or limit the effects of corrosion from the electric drive coils being in, for example, a corrosive environment, such as a biological environment (e.g., a user's ear). Alternatively, or in addition, the windings may be coated with a protective material, such as a parylene coating. The electric drive coil 716 forms a tunnel through which the armature portions 706a, 708a extend prior to extending through the gap 712.

(79) The armature portion 706a includes a drive rod 718 (not shown) that connects the armature portion 706a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 708a includes a drive rod (not shown) that connects the armature portion 708a to an acoustic valve (not shown), discussed in greater detail below.

(80) The balanced armature receiver 700 further includes a drive coil 720. Unlike, for example, what is shown for the electric drive coil 320, the electric drive coil 720 surrounds the armature portion 308a (e.g., the moveable or deflectable portion). The electric drive coil 720 can be directly coupled to the armature portion 708a. Alternatively, the electric drive coil 720 can be indirectly coupled to the armature portion 708a, such as through both being coupled to the armature assembly 704.

(81) In operation, the presence of the electric drive coil 720 allows the armature portion 708a to be driven substantially independent of the electric drive coil 716. For example, the electric drive coil 720 allows the bi-stable state of the armature portion 708a to be changed independently from an electric current pulse to the electric drive coil 716 to generate the acoustic signals. In addition, one or more mechanical and/or magnetic properties of the armature portion 708a can be varied relative to the armature portion 706a. For example, although the armature portion 708a is substantially controlled by the electric drive coil 720, the rigidity of the armature portion 708a may be less than the rigidity of the armature portion 706a.

(82) FIG. 8 shows a perspective view of a balanced armature receiver 800 based on a generally E-shaped armature with three electric drive coils, in accord with aspects of the present disclosure. Like the balanced armature receivers 200-700, and as discussed above with respect to FIG. 1, the balanced armature receiver 800 includes a housing; though not shown for illustrative convenience. Within the housing is an armature assembly 804. According to the specific arrangement of the balanced armature receiver 800, the armature assembly 804 is a modified generally E-shaped armature. Instead of having one armature portion extending from the center, the armature assembly 804 has armature portions 806a, 808a extending from the center. Specifically, the armature portion 806a is a deflectable portion of the armature assembly 804, and the armature portion 808a is a deflectable portion of the armature assembly 804. The armature assembly 804 further includes fixed portions 806b, 808b. The fixed portions 806b, 808b are coupled to the housing to fix the armature assembly 804 within the balanced armature receiver 800.

(83) The balanced armature receiver 800 further includes a magnetic housing 810. The distal ends of the armature portions 806a, 808a extend through the magnetic housing 810. The magnetic housing 810 includes a pair of permanent magnets 812. Opposing surfaces of the pair of permanent magnets 812 form a gap 814 through which the distal ends of the armature portions 806a, 808a extend.

(84) The balanced armature receiver 800 further includes a pair of electric drive coils 834 that surround the fixed armature portions 806b, 806b. The electric drive coils 834surround the non-movable fixed armature portions 806b, 808b rather than the deflectable armature portions 806a, 808a. The electric drive coils 834 can be coupled directly to the armature portions 806b, 808b. Alternatively, the electric drive coils 834 can be coupled indirectly to the armature portions 806b, 808b, such as by both being coupled to the housing.

(85) The armature portion 806a includes a drive rod (not shown) that connects the armature portion 806a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 808a includes a drive rod (not shown) that connects the armature portion 808a to an acoustic valve (not shown), discussed in greater detail below.

(86) The balanced armature receiver 800 further includes a drive coil 820. Unlike, for example, what is shown for the electric drive coil 320, the electric drive coil 820 surrounds the armature portion 808a (e.g., the moveable or deflectable portion). The electric drive coil 820 can be directly coupled to the armature portion 808a. Alternatively, the electric drive coil 820 can be indirectly coupled to the armature portion 808a, such as through both being coupled to the housing.

(87) In operation, the presence of the electric drive coil 820 allows the armature portion 708a to be driven substantially independent of the electric drive coils 834. For example, the electric drive coil 820 allows the bi-stable state of the armature portion 808a to be changed independent from an electric current pulse from the electric drive coils 834 to generate the acoustic signals.

(88) FIG. 9A shows perspective view of a balanced armature receiver 900 based on a generally E-shaped armature with two magnet stacks, in accord with aspects of the present disclosure. Like the balanced armature receivers 200-800, and as discussed above with respect to FIG. 1, the balanced armature receiver 900 includes a housing; though not shown for illustrative convenience. Within the housing is an armature assembly 904. According to the specific arrangement of the balanced armature receiver 900, the armature assembly 904 is a modified generally E-shaped armature. Instead of having one armature portion extending from the center, the armature assembly 904 has armature portions 906a, 908a extending from the center. Specifically, the armature portion 906a is a deflectable portion of the armature assembly 904, and the armature portion 908a is a deflectable portion of the armature assembly 904. The armature assembly 904 further includes fixed portions 906b, 908b. The fixed portions 906b, 908b are coupled to the housing to fix the armature assembly 904 within the balanced armature receiver 900.

(89) The balanced armature receiver 900 further includes a magnetic housing 910. The distal ends of the armature portions 906a, 908a extend through the magnetic housing 910. The magnetic housing 910 includes two pairs of permanent magnets 912, 928. Opposing surfaces of the pair of permanent magnets 912 form a gap 914 through which the distal end of the armature portion 806a extends. Opposing surfaces of the pair of permanent magnets 928 form a gap 930 through which the distal end of the armature portion 908a extends. The permanent magnets 928 can be any type of magnet that provides enough magnetic flux to keep the armature portion 908a unstable and collapsed toward the upper or lower portion of the magnetic housing 910. According to one embodiment, the permanent magnets 928 can be a rare earth magnet to, for example, reduce the size of the permanent magnets relative to a non-rare earth magnet. Although not shown, the balanced armature receiver 900 can further include a pair of spacers, such as the spacers 632.

(90) The balanced armature receiver 900 further includes an electric drive coil 916. The electric drive coil 916 forms a tunnel through which the armature portion 906a extends prior to extending through the gap 514. The balanced armature receiver 900 further includes a drive coil 920. Unlike, for example, what is shown for the electric drive coil 320, the electric drive coil 920 surrounds the armature portion 808a (e.g., the moveable or deflectable portion). The electric drive coil 920 can be directly coupled to the armature portion 908a. Alternatively, the electric drive coil 920 can be indirectly coupled to the armature portion 908a, such as through both being coupled to the housing.

(91) The armature portion 906a includes a drive rod (not shown) that connects the armature portion 906a to a diaphragm (not shown) to generate the acoustic signals. The armature portion 908a includes a drive rod (not shown) that connects the armature portion 908a to an acoustic valve (not shown), discussed in greater detail below.

(92) FIG. 9B shows a perspective view of a balanced armature receiver 900′, which is a modified version of the balanced armature receiver 900 of FIG. 9A, in accord with aspects of the present disclosure. The elements of the balanced armature receiver 900′ are the same as the balanced armature receiver 900, except for the magnetic housing 910′. To further divide the armatures portions 906a, 908a and/or provide structural support or rigidity, the magnetic housing 910′ includes a column 936.

(93) FIG. 9C shows a perspective view of a balanced armature receiver 900″, which is a modified version of the balanced armature receivers 900′ of FIGS. 9A and 9B, in accord with aspects of the present disclosure. The elements of the balanced armature receiver 900″ are the same as the balanced armature receiver 900, except for the magnetic housing 910″ and the magnetic housing 926. Rather than having a single magnetic housing, the balanced armature receiver 900″ includes two magnetic housings. The magnetic housing 910″ holds the pair of permanent magnets 912. The magnetic housing 926 holds the pair of permanent magnets 928. A gap 938 is between the magnetic housings 910″, 926. The gap 938 can be filled with a material to insulate (thermally, electrically, magnetically, and/or mechanically) the armature portion 906a from the armature portion 908a.

(94) In operation, the presence of the electric drive coil 920 allows the armature portion 908a to be driven substantially independent of the electric drive coil 916. For example, the electric drive coil 920 allows the bi-stable state of the armature portion 908a to be changed independent from an electric current pulse from the electric drive coil 916 to generate the acoustic signals. Further, the presence of the pair of permanent magnets 928 (and potentially spacers 932) coupled to the magnetic housing 910 (or magnetic housing 926) allows the armature portion 908a to be unstable and in a bi-stable state relative to the armature portion 906a. In addition, and according to all of the embodiments discussed herein, one or more mechanical and/or magnetic properties of the armature portion 908a can be varied relative to the armature portion 906a. For example, although the armature portion 908a is substantially controlled by the electric drive coil 920, the rigidity of the armature portion 908a may be less than the rigidity of the armature portion 906a.

(95) FIGS. 10A-10C show, for example, the balanced armature receiver 300, in accord with aspects of the present concepts. Thus, the elements shown in FIG. 3 discussed above are incorporated into the balanced armature receiver 300 of FIG. 10. The housing 302 further includes an aperture 1002. The aperture directs acoustic signals generated by the diaphragm (not shown), which is driven by the armature portion 306a discussed above. The housing 302 further includes an aperture 1004. The apertures 1002, 1004 generally allow for acoustic signals to pass through the interior of the balanced armature receiver 300. Thus, an acoustic pathway is generally formed between the apertures 1002, 1004 within the balanced armature receiver 300. Although the apertures 1002, 1004 are shown in the front and back of the housing 302, the locations of the apertures 1002, 1004 may vary without departing from the spirit and scope of the present disclosure.

(96) In addition to the elements discussed above with respect to FIG. 3, the balanced armature receiver includes a drive rod 1006 and a valve 1008. The drive rod 1006 connects the armature portion 308a to the valve 1008. In a closed position, the valve 1008 sits on a valve seat 1010. In one embodiment, the valve 1008 may be a hinged valve such that, for example, the end 1008a of the valve 1008 is fixed to the valve seat 1010 and the end 1008b of the valve 1008 is free to move relative to the valve seat 1010. Alternatively, the entire valve 1008 may be free so that the entire valve is free to move relative to the diaphragm 1010. According to some embodiments, a restoring force can be supplied using a spring as a resilient member, such as to restore the valve 1008 to an open or closed position. The hinge can be made as torsion hinge or normal (door hinge).

(97) FIGS. 10B and 10C show cross-sectional views of the balanced armature receiver 300 through the line 10B, 10C. Because the line 10B, 10C divides the balanced armature receiver 300 down the left side, FIGS. 10B and 10C show the armature portion 308a of the armature assembly 304. However, based on the configuration shown above in FIG. 3, the armature portion 306a, for example, is also included within the housing 302, although not shown based on the location of the line 10B, 10C.

(98) FIG. 10B shows the valve 1008 in a closed position, seated against the valve seat 1010. In such a configuration, the armature portion 308a is near or at the lower extreme of the travel length and extends toward the lower magnet 312. By way of example, and without limitation, with the valve 1008 in the closed position, the armature portion 308a is magnetically affixed to the lower magnet 312 in one of the bi-stable states. Although shown and described as touching or affixed to the lower magnet 312, the armature portion 308a may not be touching the magnet 312 but still be held in a magnetically bi-stable state such that the magnet flux provided by the magnet is sufficient to maintain the armature portion 308a in the bi-stable state. With the valve 1008 closed, the acoustic pathway through the housing 302 is closed such that the balanced armature receiver 300 is configured according to a closed fitting configuration.

(99) Referring to FIG. 10C, FIG. 10C shows the valve 1008 in an open position, not seated against the valve seat 1010. In such a configuration, the armature portion 308a is at or near the upper extreme of the travel length and extends toward the upper magnet 312. By way of example, and without limitation, with the valve 1008 in the open position, the armature portion 308a is magnetically affixed to the upper magnet 312 in one of the bi-stable states. Although shown and described as touching or affixed to the upper magnet, the armature portion 308a may not be touching the magnet 312 but still be held in a magnetically bi-stable state such that the magnet flux provided by the magnet is sufficient to maintain the armature portion 308a in the bi-stable state. With the valve 1008 open, the acoustic pathway through the housing 302 is open such that the balanced armature receiver 300 is configured according to an open fitting configuration.

(100) Thus, the armature portion 308a within the balanced armature receiver 300 forms an active valve in combination with the drive rod 1006 and the valve 1008. Control of one or both of the electric drive coils 316 and 320 allows the armature portion 308a to remain in the desired bi-stable state and the valve 1008 in the corresponding desired open or closed state. Moreover, based on one or more of the mechanical and/or magnetic qualities of the balanced armature receiver 300, the armature portion 306a, and the armature 308a, according to any one of the embodiments described above, the armature portion 308a may remain in the desired bi-stable state while the armature portion 306a drives the diaphragm to generate the acoustic signals.

(101) One or more electrical current pulses to the electric drive coil 316 and/or 320 allow for the armature portion 308a to switch to the other bi-stable state, to open or close the valve. Such an electrical current pulse may be provided by a controller after a determination is made to change the fitting of the balanced armature receiver. For example, a digital signal processor (DSP) may analyze acoustical information to determine that a user wearing a hearing air that incorporates the balanced armature receiver 300 has entered into a noisy environment. Accordingly, the DSP may generate an electrical current pulse to switch the valve 1008 from the open fitting to the closed fitting. With the closed fitting, a greater range of gain is achievable to increase the volume relative to the noisy environment. By way of another example, a user may be wearing in-ear headphones that incorporate the balanced armature receiver 300. While not playing music, the user may still have the in-ear headphones in his or her ears. By default, the balanced armature receiver 300 may be in an open fitting. Upon beginning to play music, the device playing the music, such as a smartphone or other audio device, may send an electrical current pulse to the balanced armature receiver 300 to switch to a closed fitting. Alternatively, the user may manually switch the balanced armature receiver 300 to a closed or open fitting by manually selecting a switch on a smartphone or directly on the balanced armature receiver 300 or acoustic device that incorporates the balanced armature receiver 300.

(102) Because of the unstable nature of the armature portion connected to the acoustic valve, according to some embodiments, the balanced armature receiver and/or other controller (DSP, smartphone, etc.) can determine in which position the acoustic valve is, i.e., open, close, or neither. Such detection may be beneficial if, for example, the user drops the balanced armature receiver, which causes the valve armature portion to switch states. In such a case, the valve armature portion can always restore the acoustic valve to one defined condition, such as open or closed. Preferably, the default position is an open fitting. According to some embodiments, there may be an indication. Such an indication may be beneficial for hearing aids because of the higher energy efficiency. The balanced armature receivers can further include other components, such as a vibration sensor to measure if the balanced armature receiver has dropped, or dropped with a certain acceleration. The balanced armature receiver can then reset the acoustic valve to a first state or go to the state that user wants (e.g., preferred state). The sensor may be a microelectromechanical systems (MEMS) to detect the acceleration.

(103) Although described above as being a hinged or non-hinged valve 1008, the valve 1008 may have various other forms without departing from the spirit and scope of the present disclosure. Certain forms may be, for example, an electro-active polymer valve, and/or concentric tubes to open/close a pathway. The valve may be flexible to avoid tolerances for completely open/closed conditions. According to a specific example, for a resilient member, such as a classic spring, the resilient member has only one stable state, such as at zero elongation for a classic spring. However, the resilient member can be modified to have additional stable states. For example, certain membranes can be thought of as having resiliency in that the membranes tend to restore to a stable state, such as flat. Deformations can be made to the membranes to modify the membranes to have more than one stable state. For example, using corrugations or grooves, a membrane can be designed to have two stable states. Such a membrane can be used as a flip-flop valve.

(104) FIG. 11A shows the potential energy versus elongation of a membrane-based flip-flop valve 1108, in accord with aspects of the present disclosure. The membrane-based flip-flop valve 1108 is bi-stable or has two stable states corresponding to elongations of S.sub.1 and S.sub.2. FIGS. 11B and 11C show, in part, the corresponding side profiles of the states corresponding to the elongations S.sub.1 and S.sub.2. If the membrane-based flip-flop valve 1108 is put in elongation S.sub.1 or S.sub.2, the membrane-based flip-flop valve 1108 stays in this state. If a force acts on the membrane-based flip-flop valve 1108, the force needs to overcome the local maximum potential P.sub.1 to get into the other stable state. Accordingly, forces that act on the membrane-based flip-flop valve 1108 that are less than the local maximum potential P.sub.1 have no effect on the state.

(105) FIG. 11B shows the membrane-based flip-flop valve 1108 in a first state corresponding to the elongation S.sub.1, and FIG. 11C shows the membrane-based flip-flop valve 1108 in a second state corresponding to the elongation S.sub.2. Thus, the membrane-based flip-flop valve 1108 may include bump that is either not deflected (FIG. 11B) or deflected (FIG. 11C). The membrane-based flip-flop valve 1108 can be formed of various materials, such as metals and plastics. If the membrane-based flip-flop valve 1108 is made out of plastics, the valve 1108 may not make sounds when switching between states, which may otherwise distract the user.

(106) The first state shown in FIG. 11B corresponds to the membrane-based flip-flop valve 1108 being in an open configuration, and the second state shown in FIG. 11C corresponds to the membrane-based flip-flop valve 1108 being in a closed configuration. Accordingly, to switch from the first state in FIG. 11B to the second state in FIG. 11C, a force greater than P.sub.1 must be applied to the membrane-based flip-flop valve 1108.

(107) FIGS. 11B and 11C show the membrane-based flip-flop valve 1108 in the context of the armature portion 308a discussed above. However, the membrane-based flip-flop valve 1108 is applicable to any of the armature portions discussed above. It may be desirable to not require the complete range of movement of the armature portion 308a. For example, distortions may occur that would otherwise apply a force to a valve connected to the armature portions (e.g., armature portion 308a). However, the membrane-based flip-flop valve 1108 can be used to reduce the effect of the distortions. The drive rod 1006 may not be fixed to the armature portion 306b or the valve 1108 to allow the armature portion 308a to move within the audio operation range without touching the membrane-based flip-flop valve 1108. If the armature portion 308a is driven, such as by using a bias or direct current signal with voltages outside the audio operation range, the drive rod 1006 can be moved upwards or downwards and thereby switch membrane-based flip-flop valve 1108 between its stable states. This can then be used to open or close the aperture 1110 to open or close an acoustic pathway. Alternatively, the drive rod 1006 can be fixed to the membrane-based flip-flop valve 1108. Distortions within the magnetic flux generated by an electric drive coil associated with the armature portion 308a connected to the drive rod 1006 may cause the drive rod 1006 to apply forces to the membrane-based flip-flop valve 1108. However, these forces may be less than the local maximum potential P.sub.1 of the membrane-based flip-flop valve1108 such that the forces do not change the state of the membrane-based flip-flop valve 1108. Accordingly, the membrane-based flip-flop valve 1108 may be fully seated in, for example, the first state shown in FIG. 11C. Thus, the forces applied to the membrane-based flip-flop valve 1108 that are less than the local maximum potential P.sub.1 do not affect the sealing ability of the membrane-based flip-flop valve 1108 against the valve seat 1110.

(108) The membrane-based flip-flop valve 1108 provides one embodiment of a valve that can be used in any of the embodiments disclosed herein. Moreover, based on the two stable states corresponding to elongations of S.sub.1 and S.sub.2, the membrane-based flip-flop valve 1108 is stable independent of an electric current applied to an electric drive coil associated with the armature portion 308a.

(109) FIG. 12 shows an active valve 1200 formed independent of a balanced armature receiver, in accord with aspects of the present disclosure. However, although described as a valve, the structure can be used for additional and/or alternative purposes, such as an electrical switch, a shock protector, etc. The active valve 1200 is formed based according to the principles discussed herein. Yet, the active valve 1200 is not part of a balanced armature receiver such that, for example, the active valve 1200 does not include a balanced armature receiver within the housing 1202. Rather, the housing 1202 includes a single armature 1204. The armature 1204 includes a deflectable armature portion 1204a and a fixed armature portion 1204b. The active valve 1200 further includes an electric drive coil 1206. Connected to the deflectable armature portion 1204b is a drive rod 1208. At the end of the drive rod 1208 is a valve head 1210. The valve head 1210 seats against a valve seat 1212. Attached to the fixed armature portion 1204b is a ferromagnetic element 1214.

(110) Although shown as surrounding the deflectable armature portion 1204a, alternatively the electric drive coil 1206 can surround the fixed armature portion 1204b. The electric drive coil 1206 can be formed independent of the armature 1204. Alternatively, the electric drive coil 1206 can be formed with the armature 1204, such as the windings being wrapped around the electric drive coil 1206. The electric drive coil 1206 can be attached directly to the armature 1204 or can be attached indirectly to the armature 1206, such as both being attached to the housing 1202.

(111) Upon the electric drive coil 1206 being energized, magnetic flux generated by the energized electric drive coil 1206 causes the deflectable armature portion 1204a to deflect towards the ferromagnetic element 1214. The deflectable armature portion 1204a deflecting upwards causes the drive rod 1208 to travel upwards forcing the valve head 1210 against the valve seat 1212, sealing the aperture formed by the valve seat 1212. Upon de-energizing the electric drive coil 1206, the deflectable armature portion 1204a returns to its at rest position, which lowers the drive rod 1208 and valve head 1210 and opens the aperture at the valve seat 1212. Accordingly, control of the energized state of the electric drive coil 1206 allows for control of the closed or open position of the aperture with the valve head 1210. According to some embodiments, the ferromagnetic element 1214 can be instead a permanent magnet. With a permanent magnet, the deflectable armature portion 1204a can remain magnetically affixed to the permanent magnet after de-energizing the electric drive coil.

(112) FIGS. 13A and 13B show the active valve 1200 in the form of an acoustic valve in an open and closed position, according to aspects of the present disclosure. That is, the acoustic valve is based on the active valve 1200 shown in FIG. 12. However, the valve head 1210 is replaced with a hinged valve 1300. The hinged valve 1300 opens at one end opposite of a hinged end. The housing 1202 includes ports 1302 that allow for air to enter and exit the interior of the housing 1202. In a de-energized state of the electric drive coil 1206, the hinged valve 1300 is in a closed position. Accordingly, air is restricted from entering and exiting the housing 1200 through the hinged valve 1300. However, with the electric drive coil 1206 in the energized state, the hinged valve 1300 is opened. Accordingly, an acoustic pathway is created between the opening at the ports and the opening through the hinged valve 1300.

(113) Based on the position of the drive rod 1208 coupled to the hinged valve 1300, a mechanical advantage factor can be created. Specifically, with the drive rod 1208 coupled to the hinged at one half to one tenth of the length of the hinged valve 1300 from the hinged end, a mechanical advantage factor of 2 to 10 is created. Accordingly, a small travel distance of the drive rod 1208 can make a larger opening at the end of the hinged valve 1300 opposite from the hinge.

(114) Although shown in the context of the active valve 1200, the configuration of the valve 1200 can be used in any of the embodiments discussed herein, such as any of the embodiments of the balanced armature receiver with acoustic valve discussed in FIGS. 1A-10C.

(115) FIG. 14 shows a relay 1400 based on an active control of an armature, in accord with aspects of the present concepts. The relay 1400 includes an armature 1402. The armature 1402 sits on a pair of magnets 1404. The pair of magnets 1404 sits on a core 1406. Wrapped around the core 1406 are electric drive coils 1408a, 1408a. On top of the armature 1402 is a platform 1410. The platform 1410 forms valve seats 1412a, 1412b around vent channels 1414a, 1414b. Operation of the electric drive coils allows for independent closing and opening of the valve seats 1414a, 1414b by bending, in part, of the platform 1410.

(116) FIG. 15A shows a flow diagram for using a balanced armature receiver with an integrated acoustic valve, in accord with aspects of the present concepts. At step 1502, one or more acoustic signals external to the receiver are determined. At step 1504, one or more electric drive coils associated with a first armature are energized to reproduce the one or more acoustic signals with the diaphragm. At step 1506, a state of the acoustic valve is determined based on the reproduction of the one or more acoustic signals. According to one embodiment, a frequency range of the one or more acoustic signals is analyzed to determine the state of the acoustic valve. At step 1508, one or more electric drive coils associated with the second armature are energized based, at least in part, on the state of the acoustic valve. According to one embodiment, the one or more electric drive coils associated with the second armature are energized based, at least in part, on the frequency range of the one or more acoustic signals. According to one embodiment, one or more inputs are received from an application executed on a smartphone, and the one or more electric drive coils associated with the valve armature portion are energized based, at least in part, on the one or more inputs.

(117) FIG. 15B shows flow diagram for detecting a state of an acoustic valve coupled to a balanced armature within a receiver, in accord with aspects of the present concepts. At step 1522, an impedance curve is determined as a function of frequency through the balanced armature collapsed against one of two of permanent magnets. The magnetic hysteresis curves of the two permanent magnets vary. At step 1524, the determined impedance is compared to known impedances for the balanced armature collapsed against each of the two permanent magnets. At step 1526, a state of the acoustic valve is determined based on the comparison. Subsequently, an electric coil of the balanced armature is energized to change the state of the acoustic valve based on determining that the state is off.

(118) While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the invention. It is also contemplated that additional embodiments according to aspects of the present invention may combine any number of features from any of the embodiments described herein.