CN112543402B

CN112543402B - Voice coil with outwardly extending leads and related transducers, systems and methods

Info

Publication number: CN112543402B
Application number: CN201910891743.5A
Authority: CN
Inventors: 崔纯川
Original assignee: Apple Inc
Current assignee: Apple Inc
Priority date: 2019-09-20
Filing date: 2019-09-20
Publication date: 2022-08-19
Anticipated expiration: 2039-09-20
Also published as: CN112543402A

Abstract

The present disclosure relates to voice coils having outwardly extending leads and related transducers, systems, and methods. The voice coil has an inner layer of wound filaments and an outer layer. The coiled filament extends from a first end to a second end. A segment of the wound filament adjacent the first end extends outwardly from the outer layer to the first end. A section of the coiled filament adjacent the second end extends outwardly from the outer layer to the second end. The voice coil may be coupled with the acoustic diaphragm to define an acoustic transducer.

Description

Voice coil with outwardly extending leads and related transducers, systems and methods

Technical Field

The present application and related subject matter (collectively, "the present disclosure") generally relate to voice coils of electroacoustic transducers, and related systems and methods.

Background

An electronic device may include one or more electro-acoustic transducers to emit sound. In view of size constraints, some electronic devices incorporate electroacoustic transducers configured as so-called "microspeakers". Examples of micro-speakers include speaker transducers found within headphones, headsets, smart phones, or other similar compact electronic devices (such as, for example, wearable electronics, portable timekeeping devices, or tablets, notebooks, or laptops).

Disclosure of Invention

In some aspects, the concepts disclosed herein relate broadly to voice coils, and more particularly, but not exclusively, to voice coils for speaker transducers. For example, the voice coil may be configured to cause movement of the movable diaphragm.

In an embodiment, the voice coil comprises a helical winding of electrically conductive filaments, wherein opposite ends of the filaments extend outwardly from an outermost layer of the winding. For example, a first segment of the conductive filament extends helically in a first direction about the central axis, and a second segment of the conductive filament extends helically in a second direction about the central axis. For example, the second direction may be opposite the first direction. Such a voice coil may have any suitable cross-sectional shape as a matter of design choice. For example, the voice coil may define an annular housing or a rectangular housing. Typically, but not always, the cross-sectional shape of the voice coil may correspond to the shape of the diaphragm driven by the voice coil.

According to a first aspect, an acoustic transducer has an acoustic diaphragm and a voice coil. The voice coil has an inner layer and an outer layer of filaments wound around a central region. The filament extends from a first end to a second end, and the voice coil extends from a proximal end positioned adjacent the acoustic diaphragm to a distal end. A first segment of the filament is positioned adjacent to the first end and extends along and outwardly from the outer layer to the first end. A second segment of the filament is positioned adjacent to the second end, extends along the outer layer, and extends outwardly from the outer layer to the second end.

The first segment of the filament may extend in a first circumferential direction along the outer layer. The second segment of the filament may extend in a circumferential direction along the outer layer opposite the first circumferential direction.

The outer layer may define a first region extending from the proximal end of the voice coil to a location between the proximal end and the distal end of the voice coil. A first segment of the filament may extend outwardly from the outer layer at a location between the proximal end and the distal end of the voice coil.

The position between the proximal end and the distal end of the voice coil may be a first position, and the outer layer may define a second region extending from the distal end of the voice coil to a second position between the proximal end and the distal end of the voice coil. A second segment of the filament can extend outwardly from the outer layer at a second location.

The first segment of the filament may extend outwardly from the outer layer without passing over the inner layer, and the second segment of the filament may extend outwardly from the outer layer without passing over the inner layer.

A first segment of filaments may overlie the inner layer and a second segment of filaments may overlie the inner layer.

The adhesive may join the inner and outer layers of the filament into a unitary construction.

According to another aspect, an audio device may include an amplifier circuit, an acoustic diaphragm, and a voice coil mechanically coupled to the acoustic diaphragm. The amplifier circuit is configured to adjust a gain of the received audio signal and has a first electrical output connection and a second electrical output connection. The voice coil has an outer layer, at least one inner layer, and two electrical leads. Each electrical lead extends along and outwardly from the outer layer and is electrically coupled with a corresponding one of the first and second electrical output connections.

The voice coil may include a filament defining the outer layer, the at least one inner layer, and each of the two electrical leads.

The voice coil may include a plurality of windings of conductive filament located within an adhesive.

One of the two electrical leads may extend in a first circumferential direction along the outer layer. The other of the two electrical leads may extend along the outer layer in a circumferential direction opposite the first circumferential direction.

The voice coil may extend from the proximal end to the distal end. The outer layer may define a first region extending from the proximal end of the voice coil to a first one of the two electrical leads. The outer layer may define a second region extending from the distal end of the voice coil to a second one of the two electrical leads.

The first region of the outer layer may be defined by a filament extending circumferentially from a first one of the two electrical leads in a first direction around the voice coil. The second region of the outer layer may be defined by a filament extending circumferentially from a second one of the two electrical leads in a second direction (e.g., opposite the first direction) around the voice coil.

The two electrical leads may extend outwardly from the outer layer without passing over the inner layer.

According to yet another aspect, a method for manufacturing a voice coil includes providing an electrically conductive filament having a first end, an opposite second end, and an intermediate region positioned between the first end and the second end. A first segment of the conductive filament extends from the intermediate region to the first end, and a second segment of the conductive filament extends from the intermediate region to the second end. The first layer of the coil assembly may be formed from a first segment, extending in a circumferential direction about the longitudinal axis. The first layer of the coil assembly extends longitudinally from a first longitudinal position to a second longitudinal position. The first portion of the second layer of the coil assembly may also be formed by the first segments of the conductive filaments together. The second layer overlies the first layer, and a first portion of the second layer extends longitudinally from the second longitudinal position toward the first longitudinal position. A second portion of the second layer of the coil assembly may be formed with the second segment of the conductive filament. A second portion of the second layer extends longitudinally from a first longitudinal position to a second longitudinal position. An end portion of the first segment of the conductive filament extends outwardly from the first portion of the second layer, and an end portion of the second segment of the conductive filament extends outwardly from the second portion of the second layer.

The first layer of the coil assembly may include a plurality of juxtaposed windings defined by the first segment of the conductive filament.

The act of forming the first layer of the coil assembly from the first segment may include securing the intermediate region of the conductive filament relative to the mandrel and rotating the mandrel in a first rotational direction to cause the first segment of the conductive filament to be wound into a loop around the mandrel. The act of forming the first layer of the coil assembly from the first segment may also include causing relative longitudinal movement between the mandrel and the electrically conductive filament to define a plurality of juxtaposed windings. The relative longitudinal movement may be in a first longitudinal direction, and the act of forming a first portion of a second layer of the coil assembly from the first segment of the electrically conductive filament may include causing relative longitudinal movement between the mandrel and the electrically conductive filament in a direction opposite the first longitudinal direction.

The act of forming a second portion of the second layer of the coil assembly from the second segment of the conductive filament may include rotating the mandrel in a second rotational direction to coil the second segment of the conductive filament around the first layer of the coil assembly. The act of forming the first portion of the second layer of the coil assembly from the first segment may include securing the first segment to the first layer of the coil assembly prior to rotating the hub in the second direction.

Related methods incorporating the voice coil described herein, as well as audio appliances and audio accessories, are also disclosed.

The foregoing and other features and advantages will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

Drawings

Referring to the drawings, wherein like numerals indicate like parts throughout the several views and this specification, aspects of the disclosed principles of the invention are illustrated by way of example and not by way of limitation.

Fig. 1 shows a cross-sectional view of an electroacoustic transducer.

Fig. 2A shows an intermediate configuration that may occur during the manufacture of a voice coil incorporated into the transducer of fig. 1.

FIG. 2B shows a side view of a voice coil that may be used with the transducer of FIG. 1.

Figure 2C illustrates an isometric view of the voice coil shown in figure 2B.

Fig. 3A shows an end elevational view of a portion of the voice coil in fig. 2B with electrical leads broken.

Fig. 3B shows an end elevational view of a portion of the voice coil in fig. 2B with electrical leads broken.

Figure 4 shows a cross-sectional view of another embodiment of an electroacoustic transducer.

Fig. 5A shows an intermediate configuration that may occur during the manufacture of a voice coil that is bonded to the transducer of fig. 4.

Fig. 5B shows another intermediate configuration that may occur during the manufacture of the voice coil of the transducer of fig. 4.

Figure 5C illustrates an isometric view of a voice coil that may be incorporated into the transducer of figure 4.

Fig. 6 shows a block diagram of a method for manufacturing the voice coil shown in fig. 5C.

FIG. 7 shows a block diagram illustrating aspects of an audio appliance.

Detailed Description

Various principles, associated systems and methods related to voice coils and electro-acoustic transducers are described below. For example, some disclosed principles relate to a voice coil having a pair of wire leads extending outwardly from an outer layer of the winding such that no wire lead extends beyond an exposed end of the winding layer. In contrast, existing voice coils have at least one wire extending outwardly from the inner layer of windings across the exposed ends of at least one layer of windings. Nevertheless, the descriptions herein of specific voice coils, transducers, appliances, device or system configurations, and specific combinations of method acts are merely specific examples selected to facilitate the description of the disclosed principles. One or more of the disclosed principles can be combined in various other combinations to achieve any of a variety of corresponding desired characteristics. Accordingly, one of ordinary skill in the art will recognize, after studying this disclosure, that voice coils, transducers, appliances, components, systems, and methods having attributes different from those of the specific embodiments discussed herein can embody one or more of the principles disclosed herein and can be used in applications not described in detail herein. Such alternative embodiments also fall within the scope of the present disclosure.

I. Overview

Referring to the cross-sectional view in FIG. 1, an electro-acoustic transducer 10 may have an acoustic radiator (e.g., diaphragm 12) physically coupled to an electrically driven element (e.g., voice coil 14). The acoustic radiator defines a first major surface 12a and an opposite major surface 12b, both of which extend into and out of the page, as shown in figure 1.

The voice coil 14 may cause the diaphragm 12 to reciprocate along an offset axis z (e.g., in the manner of a piston) through a stroke from a lower threshold displacement to an upper threshold displacement, represented by a double-ended arrow overlying the voice coil 14. Such strokes are also sometimes referred to in the art as "deflection" or "diaphragm deflection".

The drive element 14 may be mechanically coupled to the diaphragm and positioned in a static magnetic field defined by the

magnets

16a, 16 b. When current passes through the voice coil, the current induces a corresponding magnetic field. The induced magnetic field from the coil may interact with the static magnetic field to cause the voice coil, and thus the diaphragm, to move. When the current through the voice coil moves in a first direction, the force applied to the diaphragm is in a corresponding direction. When the current changes direction, the polarity of the induced magnetic field reverses and causes the voice coil, and thus the diaphragm, to move in the opposite direction.

As shown in fig. 1, a first end 14a of the voice coil 14 may be coupled with the diaphragm 12 and an opposing second end 14b of the voice coil may be free to reciprocate within an open space 19, such as the space defined by the

magnets

16a, 16b and the transducer base 17. In fig. 1, open space 19 is an annular slot having an open proximal end positioned adjacent septum 12 and a closed distal end defined by base 17. As shown in fig. 1, the open space 19 may have a floor 11 or other wall that can limit the degree of movement of the drive element 14 in at least one direction along the z-axis.

The voice coil typically has electrical leads, such as

leads

2a and 2b, configured to electrically couple to amplifier circuitry (not shown) and carry current from the amplifier through the voice coil 14. For example, the conductive filament may be wound into a voice coil having multiple layers and electrical leads extending from the coil, as shown in fig. 1 and 2.

In fig. 1 and 2, opposite end segments of the filament extend from the coil 14, defining a first lead 2a and a second lead 2 b. The first lead 2a extends outwardly from the inner layer 21 and the second lead 2b extends outwardly from the outer layer 22. When the lead wires 2a extend from the inner layer 21 (fig. 2C) at the distal end 14b of the coil, the lead wires 2a overlap each layer located radially outside the inner layer. As shown in fig. 2C, the lead 2a passes through the distal end 14b of the coil 14 because the coil in fig. 1 is not positioned distal to the windings from which the lead 2a extends. Thus, there is sufficient current flow through the coil 14, the distal end 14b, and thus the lead 2a may contact or impact the soleplate 11. Such contact may limit the running clearance during downward excursions of voice coil 14. Thus, the lead 2a may be damaged, for example, crushed as shown by region 23 in fig. 3A, scratched, broken, ruptured, or otherwise damaged as shown by crack 25 in fig. 3B. Such damage may reduce the reliability of the electrical leads 2a and thus the reliability of the coil 14.

The different voice coils may improve structural robustness, audio fidelity, long term reliability, or other characteristics of the transducer and associated components. For example, as schematically shown in fig. 4 and 5, the voice coil 24 may incorporate

electrical leads

4a, 4b that each extend from the coil without covering the distal end 24b of the coil, thereby reducing the likelihood of lead damage.

With the voice coil 24 as shown in fig. 4 and 5C, the conductive filament 40 extends from a first filament end 41 to an opposite second filament end 43 and defines

respective segments

45, 47 located adjacent the first and second ends. The filaments define a continuous spiral winding having a plurality of layers including an outermost layer 46 and an inner layer 48. Also, as described in greater detail below, the segment 45 adjacent the first end 41 and the segment 47 adjacent the second end 47 extend outwardly from the outermost layer 46 of the spiral winding without overlapping the distal end 24b of the inner layer 48. Each outwardly extending

segment

45, 47 of the filament may define a corresponding

electrical lead

4a, 4b to couple with an amplifier circuit for driving the voice coil 24.

Thus, the voice coil as shown in fig. 4 lacks any electrical leads that may touch or impact the floor 11, thereby eliminating a potential failure point and improving voice coil reliability. Also, because the voice coil 24 lacks electrical leads or other filaments that extend from the inner coil layer 48 through the end 24b of the outer coil layer 42, the voice coil 24 may enjoy an improved running gap in the gap 19 between the

magnets

16a, 16b, resulting in a stronger magnetic field or both, as compared to prior voice coils 14.

A variety of audio instruments and other systems may incorporate a transducer having a voice coil arranged as shown in fig. 4 and 5C. Thus, the associated transducer and system may also enjoy improved performance and reliability as compared to transducers and systems incorporating voice coils as shown in fig. 1.

Electroacoustic transducer

Still referring to the cross-sectional view in FIG. 4, an electro-acoustic transducer 20, like transducer 10 in FIG. 1, has an acoustic radiator (e.g., diaphragm) 12 physically coupled to an electrically driven voice coil 24. The acoustic radiator defines a first major surface 12a and an opposite major surface 12b, both of which extend into and out of the page, as shown in figure 4.

As with voice coil 14, voice coil 24 may include a bobbin or other member in combination with one or more windings of, for example, a conductive filament. In one aspect, voice coil 24 is formed in a laminated configuration, with each layer having a corresponding plurality of windings. Voice coil 24, on the other hand, does not include a bobbin, but is formed from laminated filament windings, for example, that have been wound around a mandrel or protrusion from diaphragm 12. The voice coil 24 may have an annular or elongated cross-sectional shape or any other cross-sectional shape suitable for driving the radiator 12.

Referring to fig. 5A-5C, electrically conductive filament 40 or wire (e.g., copper, aluminum, or copper clad aluminum) is sometimes referred to as a "voice coil wire". The bobbin is sometimes referred to in the art as a "voice coil former" or "former", and the plurality of windings is sometimes referred to in the art as a "voice coil".

Generally, the diameter or long axis of the non-circular microspeaker diaphragm may measure, for example, between about 3mm and about 75mm, such as between about 15mm and about 65mm, for example between about 20mm and about 50 mm. The minor axis of the non-circular microspeaker diaphragm may measure, for example, between about 1mm and about 70mm, such as between about 3mm and about 65mm, for example between about 10mm and about 50 mm. Voice coil 24 may have a complementary cross-sectional shape to such an elongated diaphragm. Voice coil 24 may be between about 0.5mm and about 3mm (e.g., between about 1.0mm and about 1.5 mm) as measured along a longitudinal axis (e.g., the z-axis in fig. 4).

The voice coil former (or voice coil when the former as in fig. 5A-5C is omitted) may be physically attached (e.g., bonded) to the major surface 12b of the acoustic diaphragm 12. For example, the first proximal end 24a of the voice coil 24 may be chemically or otherwise physically bonded to the second major surface 12b of the acoustic diaphragm 12. The bond may provide a platform for transmitting mechanical forces and mechanical stability to diaphragm 12. Such mechanical force may be generated between the voice coil 24 and the surrounding magnet 16 b.

As described above, the drive element 24 may be positioned in the gap between the one or more

permanent magnets

16a, 16b (e.g., NdFeB magnets) such that the member 24 is immersed in the static magnetic field generated by the one or more magnets. An electric current may pass through the coil and induce a corresponding magnetic field. The induced magnetic field from the coil may interact with the static magnetic field of the

magnets

16a, 16b to cause movement of the coil and, thus, the diaphragm 12 to which the drive element 24 is attached.

As the current varies in intensity and direction, the magnitude of the magnetic force urging movement of the electrically-driven element 24 may vary in magnitude and direction, thus causing the electrically-driven element to reciprocate, e.g., as a piston. Such reciprocating motion is depicted by a double-ended arrow covering the drive element 24. In addition, physical connection 13 between drive element 24 and acoustic diaphragm 12 may transmit the reciprocating piston movement of the drive element to the diaphragm. Voice coil 24 (and diaphragm 12) is capable of moving, e.g., piston reciprocating, and radiating sound when the corresponding current or voltage potential alternates, e.g., at an audible frequency.

Transducer module 20 has a frame (or chassis) 17 and a suspension system 15 that supportively couples acoustic diaphragm 12 to the frame. The diaphragm 12 may be hard (or rigid) and lightweight. Ideally, diaphragm 12 exhibits perfect piston motion. The diaphragm (sometimes referred to as a cone or dome, e.g., corresponding to its selected shape) may be formed of aluminum, paper, plastic, composite materials, or other materials that provide high stiffness, low mass, and may be appropriately shaped during manufacture.

The suspension system 15 generally provides a restoring force to the diaphragm 12 after an excursion driven by the interaction of the magnetic field from the drive voice coil member 24 and the one or

more magnets

16a, 16 b. Such restoring forces may return diaphragm 12 to a neutral position, for example, as shown in FIG. 4. The suspension system 15 may maintain the voice coil 24 within a desired range of positions relative to the one or

more magnets

16a, 16 b. For example, suspension 15 may provide controlled axial movement (e.g., piston movement) along axis z transverse to diaphragm 12 while largely resisting lateral movement or tilting that may cause drive element 24 to impact other motor components, such as, for example, one or

more magnets

16a, 16b or a member attached to one of the magnets. As used herein, reference to a "magnet" refers to a magnet or a magnet assembly. The magnet assembly may, in turn, comprise a magnet physically coupled to, for example, another component or coating. For example, a steel plate or other magnetic conductor may be attached to the magnet to form a magnet assembly.

The amount of resiliency (e.g., position-dependent stiffness) of the suspension 15 may be selected to match the force and deflection characteristics of the motor system (e.g., voice coil and

magnets

16a, 16 b). The exemplary suspension system 15 includes a surround that extends outwardly from an outer periphery 15a of the diaphragm 12. The surrounding member may be formed of a polyurethane foam material, a silicone material, or other pliable material. In some cases, the enclosure may be compressed into a desired shape by heat and pressure applied to the molded piece or material in the mold.

The connection 13 between the driving element 24 and the diaphragm 12 may involve attaching an edge 24a of the driving element to the second main surface 12b, e.g. a flat area defined by the second main surface 12 b. A chamfer 13a may be formed to strengthen the connecting member 13. Also or alternatively, diaphragm 12 may define one or more structural features to enhance the attachment between the diaphragm and voice coil 24.

III. Voice coil

Reference is now made to fig. 5A-5C, which depict a voice coil having electrical leads extending outwardly from a layer located on the outer side of an inner layer. Fig. 5A shows an intermediate configuration 42 during fabrication of a voice coil (e.g., voice coil 24 in fig. 4). In fig. 5A, first segment 45 of filament 40 has been wrapped around a mandrel (not shown) to define a first inner layer 48 of a coil extending from first end 49a to second end 49 b. At second end 49b, although at a location radially outward of first layer 48, filament 40 continues to be wound circumferentially about the mandrel to define a first portion of second outer layer 46 of the coil extending from second end 49b toward first end 49 a. However, the windings of outer layer 46 defined by first segment 45 of filament 40 terminate at an intermediate location between first end 49a and second end 49b, as shown in fig. 5A. Accordingly, segment 45 of wound filament 40 adjacent first end 41 extends along outer layer 46 to filament first end 41, thereby defining a first electrical lead 4a extending outwardly from outer layer 46 (fig. 4 and 5C).

In fig. 5B, a second segment 47 of filament 40, located adjacent second end 43, has been wound circumferentially around the mandrel, albeit in a direction opposite to that of first segment 45, and at a location radially outward of first inner layer 48 (e.g., along second outer layer 46). The windings of the second segment 47 define a second portion of the second outer layer 46 of the coil extending from the first end 49a towards the second end 49 b. The windings of the outer layer 46 defined by the second segment 47 terminate at an intermediate location between the first end 49a and the second end 49b, as shown in fig. 5A. Accordingly, segment 47 of wound filament 40 adjacent second end 43 extends along outer layer 46 to second end 43 of the filament, thereby defining a second electrical lead 4b extending from outer layer 46 (fig. 4 and 5C). Thus, as shown in fig. 5C, the first and

second segments

45, 47 can define respective

electrical leads

4a, 4b that extend outwardly from the outer layer 46 of the coil at a location between the first and

second ends

49a, 49b of the coil such that none of the segments 45, 47 (and none of the

electrical leads

4a, 4b) extend beyond the ends of the coil assembly 24, as shown in fig. 1.

Although only two layers of

coils

46, 48 are shown in fig. 5A-5C, a voice coil embodiment may have more than two coil layers while still providing

segments

45, 47 of filaments extending along the coil outer layer and defining

electrical leads

4a, 4b extending outwardly from the coil outer layer, e.g., not extending through the coil layers at the ends of the coil assembly. For example, first segment 45 of filament 40 may continue to be circumferentially wound, e.g., circumferentially wound around a first portion of a second layer to define a portion of a third coil layer (not shown). Such coils may extend from the intermediate position shown in fig. 5A to the second end 49 b. Another layer (e.g., a fourth layer) of the coil defined by the first segment may extend from the second end 49b to an intermediate position. Similarly, the second segment 47 of filaments may continue to wrap circumferentially around the second portion of layer 48. Such coils of the second segment 47 may extend from an intermediate position of the coil assembly to the first end 49 a. The second segment 47 can define a portion of another layer (e.g., a fourth layer) of the coil that extends from the first end 49a to an intermediate position.

With such a four-layer coil assembly, electrical leads may extend outwardly from the outermost layer at respective intermediate locations between the first end 49a and the second end 49 b. Alternatively, the three-layer coil assembly (not shown) may have a respective pair of electrical leads extending outwardly from the outermost layer adjacent the first and

second ends

49a, 49b, respectively.

In any of the foregoing embodiments, the adhesive may be interspersed among the coils of the first layer 48, the outermost layer 46, and any intermediate layers. With respect to the two layer embodiment shown in fig. 5C, adhesive may be interspersed between the coils of the first layer 48 and the second layer 467.

Such adhesives may join the continuous inner and outer layers together, defining a unitary construction. Similarly, such adhesives may be used to secure an intermediate region of filament 40 (e.g., the region positioned between first segment 45 and second segment 47) to the mandrel to prevent filament 40 from sliding relative to the mandrel and to facilitate winding of the filament around the mandrel. Additionally, such adhesives may secure the first segment 45 of the filament to one or more coils in order to facilitate winding of the second segment 47 around the mandrel without unwinding the coil defined by the first segment 45. Suitable adhesives include, for example, thermoset plastics, silicone rubbers, epoxy resins, and polyurethane compounds.

IV. method of manufacture

The block diagram in fig. 6 illustrates a method 60 suitable for manufacturing the voice coil 24 shown in fig. 4 and 5C. As described above and shown in fig. 5A, conductive filament 40 may have a first end 41 and an opposing second end 43. An intermediate region of filament 40 is positioned between first end 41 and second end 43. A first segment 45 of the conductive filament 40 extends from the intermediate region to the first end 41 and a second segment 47 of the conductive filament extends from the intermediate region to the second end 43.

The first layer 48 of the coil assembly may be formed with the first segment 45. For example, as shown in box 61 in fig. 6, a middle region of filament 40 may be secured to a mandrel (not shown). At block 62, the mandrel may be rotated in the first direction 51, winding the first segment 45 in a circumferential direction about the longitudinal axis 52. At block 63, a so-called "filament head" or spool (not shown) may guide the filament 40 as the filament 40 is fed to the mandrel. More specifically, the filament head may be moved longitudinally along the mandrel, as indicated by arrow 53 in fig. 5A, winding filament 40 around the mandrel to define each successive coil in first layer 48. By moving the filament head longitudinally, the first layer 48 of the coil assembly 42 extends longitudinally from a first longitudinal position 49a to a second longitudinal position 49 b.

At block 64, as the shaft continues to rotate in direction 51, the filament head may change longitudinal direction and move back from the second longitudinal position 49b toward the first longitudinal position 49a, for example, in a direction opposite to that indicated by arrow 53. Another layer of coils 46 is formed from the first segment 45 over the first layer 48 by changing the direction of the filament heads. At block 65, first segment 45 of filament 40 is secured adjacent outer layer 46, thereby completing intermediate construction 42 shown in fig. 5A. As shown in fig. 5A, a first portion of the layer of the second layer 46 extends longitudinally from the second longitudinal position 49b toward the first longitudinal position 49a and terminates at an intermediate position between the

ends

49a, 49 b.

At block 66, the mandrel is rotated in the opposite direction, e.g., opposite the direction indicated by arrow 51. The opposite rotation winds the second segment 47 around the first layer 48. At block 67, the filament head (not shown) of the second segment 47 is directed to move toward the tip 49b, thereby arranging the successive coils of the second segment adjacent to each other to move from the first longitudinal position 49a toward the second longitudinal position 49 b. The continuous coil defines a second portion 55 of the second layer 46, resulting in the intermediate configuration 44 shown in fig. 5B. As shown in fig. 5B, a second portion 55 of the second layer 46 extends longitudinally from the first longitudinal position 49a toward the second longitudinal position 49B. At block 68, an end portion of second segment 47 of electrically conductive filament 40 is secured adjacent outer layer 46 and extends outwardly from second portion 55 of outer layer 46.

While the foregoing discussion indicates that the mandrel is rotating and the filament head is moving longitudinally, other embodiments result in the mandrel rotating and moving longitudinally. In addition, other embodiments may result in the mandrel remaining substantially unchanged and instead causing the filament head to rotate about the mandrel as well as move in the longitudinal direction of the mandrel. In another embodiment, the filament head rotates about the mandrel and the mandrel moves longitudinally. Thus, the act of forming the first layer 48 or the second layer 46 of the coil assembly from the first segments 45 may include inducing relative longitudinal and/or circumferential motion between the mandrel and the conductive filament (or filament head of the guide filament) to define a plurality of juxtaposed windings around the mandrel, thereby providing a coil assembly as described herein.

V. Audio frequency appliance

Although not shown, speaker module 20 (fig. 4) may be positioned in an acoustic box. The acoustic box may be a stand-alone device, such as, for example, a conventional bookshelf speaker or smart speaker. Alternatively, the acoustic box may constitute a defined area within a package of a smaller portable device, such as for example a smartphone. In yet other alternative embodiments, the acoustic box may form part of a smart watch, an in-ear headphone, an on-ear headphone, or an in-ear headphone.

Also, although not shown, the speaker transducer and/or the acoustic box may include other circuitry (e.g., an Application Specific Integrated Circuit (ASIC)) or electrical devices (e.g., capacitors, inductors, and/or amplifiers) to condition and/or drive the electrical signal through the voice coil. Such circuitry may form part of the computing environment or audio appliance described herein.

For example, such circuitry may include amplifier circuitry configured to adjust the gain of the received audio signal. The amplifier circuit may have first and second electrical output connections, each connection being configured to couple with a respective one of the outwardly extending

electrical leads

4a, 4b of the transducer 20 shown in fig. 4.

Referring now to fig. 7, an electronic device incorporating the disclosed electroacoustic transducer is described by referring to a specific example of an audio appliance. Electronic devices represent one possible class of computing environments capable of incorporating the disclosed electroacoustic transducers, as described herein. However, the electronic device is briefly described with respect to a particular audio appliance 70 to convey principles related to systems incorporating and benefiting from the disclosed voice coil and associated electroacoustic transducer.

As shown in fig. 7, an audio appliance 70 or other electronic device may include, in its most basic form, a processor 74, a memory 75, and a speaker or other electroacoustic transducer 77 (e.g., transducer 20 in fig. 4), and associated circuitry (e.g., a signal bus, which is omitted from fig. 7 for clarity). The memory 75 may store instructions that, when executed by the processor 74, cause circuitry in the audio appliance 70 to drive the electro-acoustic transducer 77 to emit sound over a selected frequency bandwidth.

The audio appliance 70 schematically shown in fig. 7 also includes a communication connector 76 for establishing communication with another computing environment or audio accessory. Likewise, the audio appliance 70 includes an audio acquisition module 71 having a microphone transducer 72 that converts incident sound into an electrical signal, and a signal conditioning module 73 that conditions (e.g., samples, filters, and/or otherwise conditions) the electrical signal emitted by the microphone. Further, the memory 75 may store other instructions that, when executed by the processor, cause the audio appliance 70 to perform any of a variety of tasks similar to general computing environments, such as distributed computing environments, network connected computing environments, and stand-alone computing environments.

The audio appliance may take the form of a portable media device adapted for use with various accessory devices. The accessory device may take the form of a wearable device, such as, for example, a smart watch, an in-ear earpiece, an over-the-ear headset, and an over-the-ear headset. The accessory device may include one or more electro-acoustic transducers as described herein.

VI other embodiments

The previous description is provided to enable any person skilled in the art to make or use the disclosed principles. Embodiments other than those detailed above are contemplated based on the principles disclosed herein and any attendant changes in the configuration of the corresponding structures described herein without departing from the spirit or scope of the present disclosure.

The above examples generally relate to voice coils for "small" electroacoustic transducers and related systems and methods. However, micro-speakers work on a principle similar to larger electro-acoustic transducers. Thus, the concepts disclosed herein may be incorporated into electroacoustic transducers other than micro-speakers.

Moreover, various modifications to the examples described herein will be readily apparent to those skilled in the art. For example, the examples detailed above may omit a separate coil former (or bobbin). However, some voice coil embodiments include a bobbin or other former that applies voice coil windings in constructing the coil.

Directions and other relevant references (e.g., upward, downward, top, bottom, left, right, rearward, forward, etc.) may be used to help discuss the drawings and principles herein, and are not intended to be limiting. For example, certain terms such as "upward," "downward," "upper," "lower," "horizontal," "vertical," "left," "right," and the like may be used. These terms, where applicable, are used to provide some explicit description of relative relationships, particularly with respect to the illustrated embodiments. However, such terms are not intended to imply absolute relationships, positions, and/or orientations. For example, with respect to an object, an "upper" surface may be changed to a "lower" surface simply by flipping the object. Nevertheless, it remains the same surface and the object remains unchanged. As used herein, "and/or" means "and" or ", as well as" and "or". Further, all patent and non-patent documents cited herein are hereby incorporated by reference in their entirety for all purposes.

Moreover, those of ordinary skill in the art will understand that the exemplary embodiments disclosed herein can be adapted for various configurations and/or uses without departing from the disclosed principles. A wide variety of voice coils and associated methods and systems may be provided applying the principles disclosed herein. For example, the principles described above in connection with any particular example may be combined with the principles described in connection with another example described herein. Thus, all structural and functional equivalents to the features and method measures of the various embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the principles described herein and the features claimed. Accordingly, neither the claims nor this detailed description are to be construed in a limiting sense, and upon review of this disclosure, those of ordinary skill in the art will appreciate a wide variety of audio appliances and related methods and systems that can be designed under the disclosed and claimed concepts.

Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. To assist the patent office and any reader of any patent issued in this application in interpreting the appended claims or otherwise presented throughout the entire procedure of this application or any continuing patent application, applicants intend to note that they do not intend to interpret or otherwise refer to any claimed features as the provision of 35u.s.c. § 112(f), unless specifically recited in a particular claim "means for.

The appended claims are not intended to be limited to the embodiments shown herein, but are to be accorded the full scope consistent with the language claims, wherein reference to a feature in the singular (such as by use of the article "a" or "an") is not intended to mean "one and only one" unless specifically so stated, but rather "one or more. Furthermore, in view of the many possible embodiments to which the disclosed principles may be applied, i reserve any and all combinations of features and techniques described herein that are claimed as would be understood by one of ordinary skill in the art including, for example, all those within the scope and spirit of the following claims.

Claims

1. An acoustic transducer comprising:

an acoustic diaphragm; and

a voice coil having an inner layer and an outer layer of filament wound around a central region, wherein the filament extends from a first tip to a second tip and the voice coil extends from a proximal end positioned adjacent the acoustic diaphragm to a distal end, wherein a first segment of the filament is positioned adjacent to and extends along the outer layer and extends outwardly from the outer layer to the first tip without covering the distal end, and wherein a second segment of the filament is positioned adjacent to and extends along the outer layer and extends outwardly from the outer layer to the second tip without covering the distal end,

wherein the outer layer defines a first region extending from the proximal end of the voice coil to a location between the proximal end and the distal end of the voice coil.

2. The acoustic transducer of claim 1, wherein the first segment of the filament extends in a first circumferential direction along the outer layer.

3. The acoustic transducer of claim 2, wherein the second segment of the filament extends along the outer layer in a circumferential direction opposite the first circumferential direction.

4. The acoustic transducer of claim 1, wherein the first segment of the filament extends outwardly from the outer layer at the location between the proximal end and the distal end of the voice coil.

5. The acoustic transducer of claim 1, wherein the location between the proximal end and the distal end of the voice coil is a first location, wherein the outer layer defines a second region extending from the distal end of the voice coil to a second location between the proximal end and the distal end of the voice coil.

6. The acoustic transducer of claim 5, wherein the second segment of the filament extends outwardly from the outer layer at the second location.

7. The acoustic transducer of claim 1, wherein the first segment of the filament extends outwardly from the outer layer without passing over the inner layer, and the second segment of the filament extends outwardly from the outer layer without passing over the inner layer.

8. The acoustic transducer of claim 1, wherein the first segment of the filament overlies the inner layer and the second segment of the filament overlies the inner layer.

9. The acoustic transducer of claim 1, further comprising an adhesive joining the inner and outer layers of the filament into a unitary construction.

10. An audio device, comprising:

an amplifier circuit configured to adjust a gain of a received audio signal, wherein the amplifier circuit has a first electrical output connection and a second electrical output connection;

an acoustic diaphragm; and

a voice coil mechanically coupled with the acoustic diaphragm, wherein the voice coil extends from a proximal end positioned adjacent the acoustic diaphragm to a distal end, and wherein the voice coil has an outer layer, at least one inner layer, and two electrical leads, wherein each electrical lead extends along and outwardly from the outer layer, and wherein each electrical lead is electrically coupled with a corresponding one of the first and second electrical output connections,

wherein two electrical leads extend outwardly from the outer layer without covering the distal end.

11. The audio device of claim 10, wherein the voice coil comprises a filament defining the outer layer, the at least one inner layer, and each of the two electrical leads.

12. The audio device of claim 10, wherein the voice coil comprises a plurality of windings of conductive filament within an adhesive.

13. The audio device of claim 10, wherein one of the two electrical leads extends in a first circumferential direction along the outer layer.

14. The audio device of claim 13, wherein the other of the two electrical leads extends along the outer layer in a circumferential direction opposite the first circumferential direction.

15. The audio device of claim 10, wherein the outer layer defines a first region extending from the proximal end of the voice coil to a first one of the two electrical leads.

16. The audio device of claim 10, wherein the outer layer defines a second region extending from the distal end of the voice coil to a second one of the two electrical leads.

17. The audio device of claim 16, wherein the first region of the outer layer is defined by a filament extending circumferentially from the first one of the two electrical leads in a first direction around the voice coil.

18. The audio device of claim 17, wherein the second region of the outer layer is defined by the filament extending circumferentially from the second one of the two electrical leads around the voice coil in a second direction, wherein the second direction is opposite the first direction.

19. A method of manufacturing a voice coil, comprising:

providing an electrically conductive filament having a first end, an opposing second end, and an intermediate region positioned between the first end and the second end, wherein a first segment of the electrically conductive filament extends from the intermediate region to the first end, and wherein a second segment of the electrically conductive filament extends from the intermediate region to the second end;

forming a first layer of a coil set from the first segment, wherein the first segment extends in a first circumferential direction about a longitudinal axis, and the first layer of the coil set extends longitudinally from a first longitudinal position to a second longitudinal position;

forming a first portion of a second layer of the coil set from a first segment of the conductive filament, wherein the second layer overlies the first layer, and wherein the first portion of the second layer extends longitudinally from the second longitudinal position toward the first longitudinal position;

forming a second portion of the second layer of the coil set from the second segment of the electrically conductive filament, wherein the second portion of the second layer extends longitudinally from the first longitudinal position to the second longitudinal position, wherein an end portion of the first segment of the electrically conductive filament extends outwardly from the first portion of the second layer without covering a distal end, and wherein an end portion of the second segment of the electrically conductive filament extends outwardly from the second portion of the second layer without covering a distal end.

20. The method of claim 19, wherein the first layer of the coil assembly comprises a plurality of juxtaposed windings defined by the first segment of the conductive filament.

21. The method of claim 19, wherein the act of forming the first layer of the coil assembly from the first segment includes fixing the intermediate region of the conductive filament relative to a mandrel and rotating the mandrel in a first rotational direction to coil the first segment of the conductive filament around the mandrel.

22. The method of claim 21, wherein the act of forming the first layer of the coil assembly from the first segment further comprises causing relative longitudinal movement between the mandrel and the conductive filament to define a plurality of juxtaposed windings.

23. The method of claim 22, wherein relative longitudinal movement is in a first longitudinal direction, and wherein the act of forming the first portion of the second layer of the coil assembly from the first segment of the conductive filament comprises causing relative longitudinal movement between the mandrel and the conductive filament in a direction opposite the first longitudinal direction.

24. The method of claim 21, wherein the act of forming the second portion of the second layer of the coil assembly from the second segment of the conductive filament comprises rotating the mandrel in a second rotational direction to coil the second segment of the conductive filament around the first layer of the coil assembly.

25. The method of claim 24, wherein the act of forming the first portion of the second layer of the coil assembly from the first segment comprises securing the first segment to the first layer of the coil assembly prior to rotating the mandrel in the second direction.