PATENT DOCUMENT

Publication Number: US-10595131-B2
Application Number: US-201615254942-A
Country: US
Kind Code: B2

Title: Audio speaker having an electrical path through a magnet assembly

Abstract:
An audio speaker having a magnet assembly for directing a magnetic field through a magnetic circuit, and an electrical circuit for carrying an electrical audio signal current through at least part of the magnet assembly, are disclosed. More particularly, a voicecoil in the electrical circuit may be in electrical contact with a magnetic plate of the magnet assembly. The voicecoil may be electrically connected with a speaker driver circuit at least partly through the magnetic plate. Other embodiments are also described and claimed.

Claims:
What is claimed is: 
     
       1. An audio speaker, comprising:
 a diaphragm; 
 a magnet assembly having an air gap between an electrically conductive top plate and a center magnet, wherein the electrically conductive top plate laterally surrounds the center magnet; and 
 a voicecoil coupled to the diaphragm and movably suspended in the air gap, wherein the voicecoil includes a first terminal and a second terminal, and wherein the first terminal is in electrical contact with the top plate such that the top plate is electrically connected to the second terminal through the suspended voicecoil. 
 
     
     
       2. The audio speaker of  claim 1  further comprising a printed circuit carrier having a first conductive pad and a second conductive pad, wherein the first conductive pad is in electrical contact with the top plate and the second conductive pad is in electrical contact with the second terminal. 
     
     
       3. The audio speaker of  claim 2 , wherein the first terminal is attached to the top plate at a first top contact, wherein the first conductive pad is attached to the top plate at a second top contact, and wherein the center magnet is between the first top contact and the second top contact. 
     
     
       4. The audio speaker of  claim 3 , wherein the first conductive pad is electrically connected to the first terminal through the top plate. 
     
     
       5. The audio speaker of  claim 2 , wherein the first conductive pad is on a first side of the printed circuit carrier facing the top plate and the second conductive pad is on a second side of the printed circuit carrier facing away from the top plate. 
     
     
       6. The audio speaker of  claim 5 , wherein the printed circuit carrier is a flexible printed circuit. 
     
     
       7. An audio speaker, comprising:
 a diaphragm; 
 a magnet assembly having a center magnet mounted on an electrically conductive bottom plate and an air gap between the center magnet and an electrically conductive top plate, wherein the top plate includes a first top portion electrically insulated from a second top portion, and wherein the bottom plate includes a first bottom portion electrically insulated from a second bottom portion; and 
 a voicecoil coupled to the diaphragm and movably suspended in the air gap, wherein the voicecoil includes a first terminal and a second terminal, and wherein the first terminal is in electrical contact with the first top portion and the second terminal is in electrical contact with the second top portion such that the first top portion is electrically connected to the second top portion through the suspended voicecoil. 
 
     
     
       8. The audio speaker of  claim 7 , wherein the bottom plate is below the center magnet and the top plate, and wherein the first top portion is electrically connected to the first bottom portion and the second top portion is electrically connected to the second bottom portion. 
     
     
       9. The audio speaker of  claim 8 , wherein the magnet assembly includes a side magnet between the top plate and the bottom plate. 
     
     
       10. The audio speaker of  claim 9 , wherein the first terminal is attached to the first top portion at a first top contact and the second terminal is attached to the second top portion at a second top contact, and wherein the first top contact and the second top contact are laterally offset from the side magnet. 
     
     
       11. The audio speaker of  claim 10  further comprising a first bottom contact on the first bottom portion and a second bottom contact on the second bottom portion, wherein the first bottom contact is electrically connected to the first terminal through the first top portion and the first bottom portion, and wherein the second bottom contact is electrically connected to the second terminal through the second top portion and the second bottom portion. 
     
     
       12. The audio speaker of  claim 9 , wherein the side magnet extends over a bottom gap between the first bottom portion and the second bottom portion. 
     
     
       13. The audio speaker of  claim 12  further comprising a first insulating bonding layer between the center magnet and the bottom plate. 
     
     
       14. The audio speaker of  claim 13  further comprising a second insulating bonding layer between the side magnet and the bottom plate. 
     
     
       15. The audio speaker of  claim 14  further comprising a third insulating bonding layer between the side magnet and the top plate. 
     
     
       16. The audio speaker of  claim 15 , wherein the insulating bonding layers include respective adhesives and dielectric spacers. 
     
     
       17. An audio speaker, comprising:
 a diaphragm; 
 a magnet assembly having a center magnet mounted on a bottom plate and an air gap between the center magnet and a top plate, wherein the top plate includes a first top portion electrically insulated from a second top portion by a top gap, and wherein the magnet assembly includes a side magnet having a first magnet portion electrically insulated from a second magnet portion by a magnet gap, the first magnet portion between the first top portion and the bottom plate and the second magnet portion between the second top portion and the bottom plate; and 
 a voicecoil coupled to the diaphragm and movably suspended in the air gap, wherein the voicecoil includes a first terminal and a second terminal, wherein the first terminal is in electrical contact with the first top portion, and wherein the second terminal is in electrical contact with the second top portion such that the first top portion is electrically connected to the second top portion through the suspended voicecoil. 
 
     
     
       18. The audio speaker of  claim 17 , wherein the bottom plate includes a first bottom portion electrically insulated from a second bottom portion by a bottom gap, wherein the first magnet portion is between the first top portion and the first bottom portion, and wherein the second magnet portion is between the second top portion and the second bottom portion. 
     
     
       19. The audio speaker of  claim 18  further comprising a first dielectric spacer between the first magnet portion and the first top portion, a second dielectric spacer between the second magnet portion and the second top portion, a third dielectric spacer between the first magnet portion and the first bottom portion, and a fourth dielectric spacer between the second magnet portion and the second bottom portion. 
     
     
       20. The audio speaker of  claim 19 , wherein the magnet gap extends between the top gap and the bottom gap. 
     
     
       21. A device, comprising:
 an audio speaker including
 a diaphragm, 
 a magnet assembly having an air gap between an electrically conductive top plate and a center magnet, wherein the electrically conductive top plate laterally surrounds the center magnet, and 
 a voicecoil coupled to the diaphragm and movably suspended in the air gap, wherein the voicecoil includes a first terminal and a second terminal, and wherein the first terminal is in electrical contact with the top plate such that the top plate is electrically connected to the second terminal through the suspended voicecoil. 
 
 
     
     
       22. The device of  claim 21  further comprising:
 a speaker driver circuit; and 
 a printed circuit carrier electrically coupled to the speaker driver circuit and the audio speaker, wherein the printed circuit carrier has a first conductive pad and a second conductive pad, wherein the first conductive pad is in electrical contact with the top plate and the second conductive pad is in electrical contact with the second terminal. 
 
     
     
       23. The device of  claim 22  further comprising one or more of a display or a microphone. 
     
     
       24. The device of  claim 22 , wherein the first conductive pad is electrically connected to the first terminal through the top plate.

Description:
This application claims the benefit of U.S. Provisional Patent Application No. 62/221,506, filed Sep. 21, 2015, and this application hereby incorporates herein by reference that provisional patent application in its entirety. 
    
    
     BACKGROUND 
     Field 
     Embodiments related to an audio speaker having an electrical circuit, for carrying an electrical audio signal current, and a magnet assembly, are disclosed. In an embodiment, the electrical circuit includes an electrical path passing through the magnet assembly. 
     Background Information 
     A portable consumer electronics device, such as a mobile phone, a tablet computer, or a portable media device, typically includes a system enclosure surrounding internal system components, such as audio speakers. Such devices may have small form factors with limited internal space. Thus, the integrated audio speakers may be microspeakers, also known as microdrivers, which are miniaturized implementations of loudspeakers having a broad frequency range. 
     Microspeakers typically include a magnetic circuit consisting of one or more magnets sandwiched between pieces of magnetic steel. The magnetic steel directs a magnetic field generated by the magnets toward a voicecoil. Thus, when an electrical audio signal current is delivered through the voicecoil, the voicecoil moves to generate sound. Terminal leads of the voicecoil are typically attached to a rigid substrate to receive the electrical audio signal. For example, the terminal leads may be welded to respective contact pads on the rigid substrate, and external leads may be routed into the microspeaker around the one or more magnets to electrically connect to the contact pads and deliver the electrical audio signal to the terminal leads. 
     SUMMARY 
     External leads, routed into and/or through a microspeaker to complete an electrical circuit with a voicecoil, occupy valuable space. If the number of external leads could be reduced, then space may be freed up to increase a size of a magnet for better sound output, or to shrink the microspeaker size even further. 
     In an embodiment, an audio speaker utilizes the electrical properties of a magnet assembly, in addition to the magnetic properties of the magnet assembly, to reduce the number of external leads routed through the audio speaker and/or the volume of space required for the routing. The audio speaker may include a diaphragm and a magnet assembly. An air gap may be located between an electrically conductive top plate and a center magnet of the magnet assembly. Furthermore, the electrically conductive top plate may laterally surround the center magnet. Thus, a wire coil having two terminals may be coupled to the diaphragm and suspended in the air gap, and may be laterally surrounded by the center magnet. 
     In an embodiment, a first terminal of the wire coil is in electrical contact with the top plate of the magnet assembly. For example, the first terminal may be attached, e.g., spot welded, to the top plate. The audio speaker may also include a printed circuit carrier, e.g., a flexible printed circuit, having several conductive pads. A first conductive pad may be in electrical contact with the top plate and a second conductive pad may be in electrical contact with the wire coil. For example, the first conductive pad may be attached, e.g., spot welded, to the top plate, and the second conductive pad may be attached, e.g., spot welded, to the second terminal of the wire coil. The conductive pads may be on opposite sides of the printed circuit carrier in essentially the same location. Furthermore, the first terminal and the second terminal of the wire coil may be separated along the top plate. Thus, the top plate may electrically connect first conductive pad to the first terminal. That is, the top plate may provide a segment of the electrical circuit of audio speaker. 
     In an embodiment, the electrically conductive top plate may include several electrically insulated portions. The first terminal of the wire coil may be in electrical contact with a first portion of the top plate, and the second terminal of the wire coil may be in electrical contact with a second portion of the top plate. The magnet assembly may further include a bottom plate below the center magnet and the top plate, e.g., the center magnet may be mounted on an electrically conductive bottom plate, and the bottom plate may include several electrically insulated portions. The first portion of the top plate may be electrically connected to a first portion of the bottom plate, and the second portion of the top plate may be electrically connected to a second portion of the bottom plate. The first portion of the bottom plate may be electrically insulated form the second portion of the bottom plate. Furthermore, the portions of the bottom plate may include respective contacts, e.g., a first bottom contact and a second bottom contact. Thus, the first bottom contact may be electrically connected to the first terminal through the first portions of the top and bottom plates, and the second bottom contact may be electrically connected to the second terminal through the second portions of the top and bottom plates. 
     The magnet assembly may include a side magnet positioned between the top plate and the bottom plate to generate a magnetic field. In an embodiment, the first terminal of the wire coil is attached to the first portion of the top plate at a first top contact and the second terminal of the wire coil is attached to the second portion of the top plate at a second top contact. The first top contact and the second top contact may be laterally offset from the side magnet such that electrical current passing through the contacts does not intersect the magnetic field. 
     In an embodiment, a center magnet and a side magnet extend over a gap between the portions of the top plate and/or bottom plate. The magnets may be insulated from the bottom plate and/or top plate, however, to prevent electrical shorting between the portions of the magnet assembly. For example, a first insulating bonding layer may be disposed between the center magnet and the bottom plate, and a second insulating bonding layer may be disposed between the side magnet and the bottom plate. Similarly, a third insulating bonding layer may be disposed between the side magnet and the top plate. The insulating bonding layers between the magnets and respective magnet assembly components may include an adhesive and/or one or more dielectric spacers. 
     In an embodiment, the side magnet may be between the top plate and the bottom plate, and the plates may be divided into portions by respective gaps. The first terminal of the wire coil may be in electrical contact with the first portion of the top plate, and the second terminal of the wire coil may be in electrical contact with the second portion of the top plate. The side magnet may include first and second magnet portions disposed between respective portions of the top plate and bottom plate. For example, the first magnet portion may be between the first top portion and the bottom plate, and the second magnet portion may be between the second top portion and the bottom plate. One or more dielectric spacers may also be disposed between magnet portions and the respective plate portions to insulate the magnet portions from the magnetic plate portions. Furthermore, the first magnet portion may be electrically insulated from the second magnet portion by a magnet gap, e.g., an air-filled void, which extends between the gaps that divide the magnetic plate portions. 
     The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pictorial view of an electronic device in accordance with an embodiment. 
         FIG. 2  is a schematic view of an electronic device in accordance with an embodiment. 
         FIG. 3  is a perspective view of an audio speaker in accordance with an embodiment. 
         FIG. 4  is an exploded view of a portion of an audio speaker having a magnet assembly and a wire coil in accordance with an embodiment. 
         FIG. 5  is a sectional view, taken about line A-A of  FIG. 3 , of an audio speaker in accordance with an embodiment. 
         FIG. 6  is a sectional view, taken about line B-B of  FIG. 3 , of an audio speaker in accordance with an embodiment. 
         FIG. 7  is a detail view, taken from Detail A of  FIG. 6 , of an insulating bonding layer in accordance with an embodiment. 
         FIG. 8  is a top view of a portion of an audio speaker having a wire coil electrically connected to a magnet assembly in accordance with an embodiment. 
         FIG. 9  is an exploded view of a portion of an audio speaker having a magnet assembly and a wire coil in accordance with an embodiment. 
         FIG. 10  is a sectional view, taken about line A-A of  FIG. 3 , of an audio speaker in accordance with an embodiment. 
         FIG. 11  is a sectional view, taken about line B-B of  FIG. 3 , of an audio speaker in accordance with an embodiment. 
         FIG. 12  is a top view of a portion of an audio speaker having a wire coil electrically connected to a magnet assembly in accordance with an embodiment. 
         FIG. 13  is an exploded view of a portion of an audio speaker having a magnet assembly and a wire coil in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments describe an audio speaker having a magnet assembly for directing a magnetic field through a magnetic circuit, and an electrical circuit for carrying an electrical audio signal current through at least a portion of the magnet assembly. However, while some embodiments are described with specific regard to integration of the audio speaker within mobile electronics devices, such as handheld devices, the embodiments are not so limited and certain embodiments may also be applicable to other uses. For example, an audio speaker as described below may be incorporated into other devices and apparatuses, including desktop computers, laptop computers, wearable computers, or motor vehicles, to name only a few possible applications. 
     In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions, and processes, in order to provide a thorough understanding of the embodiments. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the description. Reference throughout this specification to “one embodiment,” “an embodiment,” or the like, means that a particular feature, structure, configuration, or characteristic described is included in at least one embodiment. Thus, the appearance of the phrase “one embodiment,” “an embodiment,” or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     The use of relative terms throughout the description may denote a relative position or direction. For example, “over” may indicate a first direction away from a reference point. Similarly, “under” may indicate a location in a second direction orthogonal to the first direction. Such terms are provided to establish relative frames of reference, however, and are not intended to limit the use or orientation of an audio speaker (or components of the audio speaker) to a specific configuration described in the various embodiments below. 
     In an aspect, an audio speaker includes a magnet assembly having several magnetic components arranged to focus a magnetic field in an air gap. A wire coil, e.g., a voice coil, may be suspended within the air gap to carry an electrical audio signal current through the magnetic field such that the wire coil and a diaphragm coupled to the wire coil move relative to the magnet assembly to generate sound. In an embodiment, the wire coil includes a first terminal and a second terminal, and at least one of the terminals is in electrical contact with the magnet assembly. For example, the first terminal may be attached to an electrically conductive top plate of the magnet assembly. In an embodiment, the second terminal is attached to a first conductive pad of a printed circuit carrier and a second conductive pad of the printed circuit carrier is attached to the top plate. Thus, the top plate forms a portion of the electrical circuit that carries electrical current through the wire coil. Accordingly, the electrical connection between the printed circuit carrier and the wire coil may be made at a single location on the top plate, eliminating a need for an additional external lead to connect to the first terminal of the wire coil. As such, space that would be occupied by the additional external lead may instead be used to increase the size of other speaker components, e.g., magnets of the magnet assembly, or to further miniaturize the audio speaker. 
     In an aspect, an audio speaker includes a wire coil having two terminals, both of which are attached to respective components of the magnet assembly. For example, a first terminal of the wire coil may be in electrical contact with a first portion of a top plate, and a second terminal of the wire coil may be in electrical contact with a second portion of the top plate. The first portion and the second portion of the top plate may be electrically insulated from each other, e.g., by an air gap, such that electrical current flowing into the first portion passes to the second portion through the wire coil. In an embodiment, the portions of the top plate are electrically connected to respective portions of a bottom plate in the magnet assembly. Accordingly, an electrical circuit may be formed through the bottom plate, the top plate, and the wire coil, eliminating a need for external leads to carry an electrical audio signal current to the wire coil terminals. As such, space that would be occupied by the external leads may instead be used to increase the size of other speaker components, e.g., magnets of the magnet assembly, or to further miniaturize the audio speaker. 
     Referring to  FIG. 1 , a pictorial view of an electronic device is shown in accordance with an embodiment. An electronic device  100  may be a smartphone device. Alternatively, it could be any other portable or stationary device or apparatus, such as a laptop computer, a tablet computer, a wearable computer, a wristwatch device, etc. Electronic device  100  may include various capabilities to allow the user to access features involving, for example, calls, voicemail, music, e-mail, internet browsing, scheduling, or photos. Electronic device  100  may also include hardware to facilitate such capabilities. For example, a casing  102  may contain an audio speaker  104 , e.g., a microspeaker, to deliver a far-end voice to a near-end user during a call, and a microphone  106  to pick up the voice of the user during the call. Audio speaker  104  may also emit sounds associated with music files played by a music player application running on electronic device  100 . A display  108  may present the user with a graphical user interface to allow the user to interact with electronic device  100  and/or applications running on electronic device  100 . Other conventional features are not shown but may of course be included in electronic device  100 . 
     Referring to  FIG. 2 , a schematic view of an electronic device is shown in accordance with an embodiment. As described above, electronic device  100  may be any of several types of portable or stationary devices or apparatuses with circuitry suited to specific functionality. Accordingly, the diagrammed circuitry is provided by way of example and not limitation. Electronic device  100  may include one or more processors  202  to execute instructions to carry out the different functions and capabilities described above. Instructions executed by processor(s)  202  of electronic device  100  may be retrieved from a local memory  204 , and may be in the form of an operating system program having device drivers, as well as one or more application programs that run on top of the operating system. The instructions may cause electronic device  100  to perform the different functions introduced above, e.g., phone and/or music play back functions. To perform such functions, processor(s)  202  may directly or indirectly implement control loops and receive input signals from and/or provide output signals to other electronic components, such as audio speaker  104 . 
     Referring to  FIG. 3 , a perspective view of an audio speaker is shown in accordance with an embodiment. An audio speaker  104  may be any type of loudspeaker. For example, audio speaker  104  may be a microspeaker. A microspeaker, also known as a microdriver, is a miniaturized implementation of a loudspeaker having a broad frequency range. Audio speaker  104  may have a small form factor defined by an exterior surface of a housing or a frame  302 , a diaphragm  304 , and a surround  306  suspending the diaphragm  304  relative to the housing or frame  302 . These components may have various geometries that combine to create an outer envelope of audio speaker  104 , and although the outer envelope is represented in  FIG. 3  as having essentially a rectangular cuboid shape, the outer envelope may be other shapes, e.g., cylindrical, to facilitate placement of audio speaker  104  within a corresponding internal space of electronic device  100 . 
     Audio speaker  104  may include a signal lead  308 , e.g., one or more printed leads on a printed circuit carrier, that connects to an external audio driver amplifier. Signal lead  308  may be routed into and/or through frame  302  to connect to terminals of a voice coil, and to form an electrical circuit. As described below, portions of a magnet assembly within audio speaker  104  may complete the electrical circuit between the voice coil and signal lead  308 . 
     Referring to  FIG. 4 , an exploded view of a portion of an audio speaker having a magnet assembly and a wire coil is shown in accordance with an embodiment. A magnet assembly of audio speaker  104  may include several permanent magnet components and several components having high magnetic permeability. For example, the magnet assembly may include a three magnet design in which a center magnet  402  is flanked by two side magnets  404 . Center magnet  402  and/or side magnets  404  may be mounted on bottom plate  408 . Thus, center magnet  402  may be sandwiched between a center plate  406  and a bottom plate  408 . Similarly, side magnets  404  may be sandwiched between a top plate  410  and bottom plate  408 . Top plate  410  may laterally surround center magnet  402  and/or center plate  406 . More particularly, top plate  410  may include an annular structure having a central opening such that center magnet  402  and/or center plate  406  are aligned with the central opening and top plate  410  circumscribes center magnet  402  and center plate  406  when viewed from the top. Accordingly, top plate  410  may be extend continuously at a constant or variable lateral distance from a center of center magnet  402  and/or center plate  406 , e.g., over a circular or rectangular path around center magnet  402  and/or center plate  406 . The magnets may be formed from the same or different types of permanent magnet materials, which may be any permanent magnet material known in the art. Similarly, the magnetic plates of the magnet assembly may be formed from known magnetic materials, including magnetic steel or other high permeability materials, e.g., high permeability iron-cobalt (FeCo) alloys. 
     In an embodiment, the arrangement of magnets and magnetic plates provide a magnetic circuit to direct a magnetic field generated by center magnet  402  and side magnets  404 . The magnetic circuit may traverse center plate  406 , top plate  410 , and bottom plate  408  to form a magnetic loop. More particularly, center magnet  402  and side magnets  404  may be permanent magnets having respective opposite poles, and thus, center magnet  402  may generate a magnetic field in a first direction, e.g., upward, and side magnets  404  may generate a magnetic field in an opposite direction, e.g., downward. The magnetic fields may be conveyed laterally between the magnets through center plate  406 , top plate  410 , and bottom plate  408 . More particularly, the magnetic field may flow laterally between center plate  406  and top plate  410  across an air gap  412 . Air gap  412  may be an annular space around center magnet  402 , and air gap  412  may separate center plate  406  from top plate  410 . Accordingly, air gap  412  provides a void to receive another speaker component, such as a wire coil  414 . 
     Wire coil  414  may be disposed within air gap  412  of a stationary magnet assembly of audio speaker  104 . The wire coil  414  may include numerous turns or loops wound around a former having a cross-sectional shape similar to air gap  412 . For example, the air gap  412  may be a cylindrical, annular void and the former may be a cylindrical, annular tube. The former may be attached to surround  306 , and thus, surround  306  may suspend the former and wire coil  414  within air gap  412 . Accordingly, by passing an electrical current through the loops of wire coil  414 , a corresponding magnetic field may be produced. The corresponding magnetic field may react with the magnetic field focused in air gap  412  by the magnet assembly to move wire coil  414 , the former, and surround  306 . More particularly, diaphragm  304  attached to surround  306  may be moved to radiate sound from audio speaker  104 . 
     The electrical current used to drive audio speaker  104  may be passed through wire coil  414  from a first end of the coil winding to a second end of the coil winding. More particularly, the first end may be part of a first terminal  416  of wire coil  414  and the second end may be part of a second terminal  418  of wire coil  414 . The terminals of wire coil  414  include not only the ends but also a region of wire coil  414  between the windings and the ends, e.g., a 5-10 mm length of material near the ends, that may be placed in electrical contact with other audio speaker components to transfer the electrical current through the electrical circuit. 
     Referring to  FIG. 5 , a sectional view, taken about line A-A of  FIG. 3 , of an audio speaker is shown in accordance with an embodiment. Wire coil  414  may be connected to diaphragm  304  and suspended within air gap  412  by surround  306 . More particularly, wire coil  414  may be positioned in air gap  412  between center plate  406  and top plate  410 , and the magnetic circuit may pass between the plates to intersect wire coil  414 . In an embodiment, at least one of the terminals of wire coil  414  is in electrical contact with a magnetic component of the magnet assembly. For example, first terminal  416  of wire coil  414  may be placed in electrical contact with top plate  410 . Thus, an electrical audio signal current may pass through wire coil  414  into top plate  410  such that the electrical circuit carrying the audio signal includes wire coil  414  and at least a portion of top plate  410 . The electrical circuit may be completed by one or more external leads electrically connected to wire coil  414  and/or top plate  410 . 
     In an embodiment, a printed circuit carrier  502  electrically connects an external electrical component, such as an audio driver amplifier, with wire coil  414  and/or top plate  410  within audio speaker  104 . Printed circuit carrier  502  may be, for example, a flexible printed circuit having one or more screen printed silver circuits on a polyester substrate. Printed circuit carrier  502  may also be another type of flexible circuit known in the art. The electrical leads of printed circuit carrier  502  may terminate at respective conductive pads, which may be placed in electrical contact with wire coil  414  and/or top plate  410 . For example, a first electrical lead of printed circuit carrier  502  may terminate at a first conductive pad  504  that is placed in electrical contact with top plate  410 . Similarly, a second electrical lead of printed circuit carrier  502  may terminate at a second conductive pad  506  that is placed in electrical contact with wire coil  414 . 
     As described further below, printed circuit carrier  502  may attach to wire coil  414  and top plate  410  at a different location than a location where first terminal  416  attaches to top plate  410 . For example, second conductive pad  506  of printed circuit carrier  502  may be spot welded to second terminal  418  at an opposite end of wire coil  414  from first terminal  416 . Similarly, first conductive pad  504  of printed circuit carrier  502  may attach to top plate  410  at a contact point adjacent to second conductive pad  506 , and thus, the contact point may be separated from the attachment of first terminal  416  to top plate  410  by essentially a same distance that second terminal  418  is separated from first terminal  416 . In an embodiment, first conductive pad  504  is positioned on a first side of printed circuit carrier  502 , e.g., on a bottom side of printed circuit carrier  502 , and second conductive pad  506  is positioned on a second side of printed circuit carrier  502 , e.g., on a top side of printed circuit carrier  502 . Thus, first conductive pad  504  may face top plate  410  and second conductive pad  506  may face away from top plate  410  such that an electrical contact between printed circuit carrier  502  and top plate  410  may be at essentially the same lateral location as, e.g., vertically aligned with, the electrical contact between printed circuit carrier  502  and second terminal  418 . The electrical contacts may nonetheless be electrically insulated from each other by the substrate of printed circuit carrier  502 . More particularly, the electrical circuit within audio speaker  104  may have an input and an output terminal at essentially the same location to allow printed circuit carrier  502  to be routed to the single location through a single entrance in frame  302  and/or to minimize a volume of external leads being routed through the space within audio speaker  104 . 
     An electrical audio signal current may flow through top plate  410  from the electrical contact with wire coil  414  to the electrical contact with printed circuit carrier  502 . More particularly, first conductive pad  504  on printed circuit carrier  502  may be electrically connected to first terminal  416  of wire coil  414  through top plate  410 . As shown in  FIG. 4 , top plate  410  may be shaped as a rectangular annulus having two short sides and two long sides connected at right angles. In an embodiment, first terminal  416  may be attached to top plate  410  on one of the short sides and first conductive pad  504  may be connected to top plate  410  on the other short side. Thus, electrical current may flow between the short side in contact with first terminal  416  and the short side in contact with printed circuit carrier  502  through at least one of the long sides. The electrical current may travel through top plate  410  around center magnet  402 , which may be located laterally between the side segments of top plate  410 . 
     Still referring to  FIG. 5 , top plate may be electrically insulated from other components of the magnet assembly to prevent electrical current from straying outside of an intended electrical circuit path. For example, top plate  410  may be supported above bottom plate  408  by frame  302 , and frame  302  may be formed from a dielectric material such as a dielectric polymer to prevent the flow of electrical current from top plate  410  into frame  302 . Top plate  410  may also be physically supported above bottom plate  408  by a structural feature, such as a yoke support  508 , that separates top plate  410  from bottom plate  408 . Such structural features may be formed from dielectric polymers to prevent the flow of electrical current from top plate  410  into bottom plate  408 . Top plate  410  may be electrically insulated from center plate  406  and center magnet  402  by air gap  412 . Thus, an electrical circuit between the terminal conductive pads of printed circuit carrier  502  may be routed through wire coil  414  and top plate  410 , and may be isolated from other components of the magnet assembly. 
     Top plate  410  may be insulated to further prevent electrical shorting between a surface area of top plate  410  and an external structure or component. For example, top plate  410  may be masked or coated with an insulating material to cover the surface area of top plate  410 , with the exception of the areas where an electrical connection is made between first terminal  416  or first conductive pad  504 . In an embodiment, top plate  410  is coated by a dielectric material, e.g., an insulating polymer, and one or more opening is formed in the coating to attach first conductive pad  504  or first terminal  416  to top plate  410 . Thus, electrical current may flow between the attachment points at the exposed openings through top plate  410 . Furthermore, the electrical current may be constrained within the conductive portion of top plate  410  and insulated from the surrounding environment to reduce a likelihood of an electrical short between top plate  410  and an external structure or component. 
     Referring to  FIG. 6 , a sectional view, taken about line B-B of  FIG. 3 , of an audio speaker is shown in accordance with an embodiment. Top plate  410  may include one or more sides positioned over side magnets  404 . For example, when top plate  410  has a rectangular annulus shape, the long sides may rest on the side magnets  404 , which may be sandwiched between top plate  410  and bottom plate  408 . The magnets of the magnet assembly, e.g., side magnet  404 , may be electrically conductive. For example, one or more of the magnets may have a zinc or nickel conductive plating, and thus, it may be necessary to insulate side magnets  404  from top plate  410  to prevent the electrical audio signal current within top plate  410  from passing into the magnets. Accordingly, an insulating bonding layer  602  may be disposed between top plate  410  and side magnet  404 . 
     Referring to  FIG. 7 , a detail view, taken from Detail A of  FIG. 6 , of an insulating bonding layer is shown in accordance with an embodiment. Insulating bonding layer  602  may electrically insulate one component of the magnet assembly from another component of the magnet assembly, and may also physically connect the magnet assembly components to each other. For example, insulating bonding layer  602  may be disposed between top plate  410  and side magnet  404  to space top plate  410  and side magnet  404  apart by a predetermined distance. More particularly, insulating bonding layer  602  may include one or more dielectric spacer  702  pressed between top plate  410  and side magnet  404 . Dielectric spacer  702  may have a predetermined outer dimension and a rigidity that prevents top plate  410  and side magnet  404  from squeezing together to make electrical contact with each other during assembly or use. For example, dielectric spacer  702  may be a glass bead having a predetermined diameter such that the bead physically contacts top plate  410  and side magnet  404  to separate the components. In an embodiment, dielectric spacers  702  provide a gap between the spaced components. Furthermore, at least a portion of the gap may be filled by a second dielectric material. For example, dielectric spacers  702  may be suspended within an adhesive  704 . Adhesive  704  may bind dielectric spacers  702  together, and may adhere top plate  410  to side magnet  404 . 
     Referring to  FIG. 8 , a top view of a portion of an audio speaker having a wire coil electrically connected to a magnet assembly is shown in accordance with an embodiment. The electrical current path through the magnet assembly may complete an electrical circuit with an external electronic components. For example, electrical leads of printed circuit carrier  502  connected to first conductive pad  504  and second conductive pad  506  may extend away from audio speaker  104  to a speaker driver circuit  802 . Speaker driver circuit  802  may be, for example, an audio driver amplifier that receives an audio signal  804  from electronic device  100  circuitry and amplifies the signal to provide the electrical current that passes through wire coil  414  and top plate  410 . More particularly, the electrical current may be input to first conductive pad  504  and output from second conductive pad  506 , or vice versa. 
     In an embodiment, first conductive pad  504  and second conductive pad  506  are positioned along a same length of top plate  410 . More particularly, first conductive pad  504  may be laterally adjacent to second conductive pad  506  on printed circuit carrier  502 . Second conductive pad  506  may be above a substrate of printed circuit carrier  502 , and thus, second terminal  418  of wire coil  414  may extend over a top surface of top plate  410  and above printed circuit carrier  502  to be spot welded to second conductive pad  506 . Similarly, first terminal  416  of wire coil  414  may extend over the top surface of top plate  410  to connect to top plate  410  at a first top contact  806 . Accordingly, the electrical current may pass between second conductive pad  506  and first top contact  806  through wire coil  414 . As such, the electrical current may travel through wire coil  414  around center magnet  402  and within air gap  412 . Thus, the electric current may pass through the magnetic field of audio speaker  104 . The electrical current may then travel between first top contact  806 , located on a first length of top plate  410 , and the second top contact  808 , located on a second length of top plate  410 . Second top contact  808  may also be on the top surface of top plate  410 , e.g., may be at a location where first conductive pad  504  is spot welded to the top surface of top plate  410 . Thus, center magnet  402  may be laterally between first top contact  806  and second top contact  808  such that the electrical current travels through top plate  410  around center magnet  402  and air gap  412 . 
     Referring to  FIG. 9 , an exploded view of a portion of an audio speaker having a magnet assembly and a wire coil is shown in accordance with an embodiment. The electrical audio signal current may pass through several components of the magnet assembly. More particularly, in an embodiment, first terminal  416  and second terminal  418  of wire coil  414  are in electrical contact with one or more component of the magnet assembly. The magnet assembly may have a three magnet design similar to that described above with respect to  FIG. 4 . Thus, center magnet  402  and two side magnets  404  may be sandwiched between top plate  410  and bottom plate  408  to form an air gap  412  within which wire coil  414  is suspended. Accordingly, the magnet assembly may provide a magnetic circuit having a magnetic field focused in air gap  412  between center plate  406  and top plate  410  (or center magnet  402 ). One or more of top plate  410  and bottom plate  408 , however, may be segmented into electrically insulated portions. 
     In an embodiment, top plate  410  includes a first top portion  902  physically separated from a second top portion  904  by a top gap  906 . Top gap  906  may be a void between first top portion  902  and second top portion  904 , e.g., an air gap  412 . Alternatively, top gap  906  may be filled by a dielectric material that physically connects first top portion  902  to second top portion  904  while electrically insulating first top portion  902  from second top portion  904 . Top gap  906  may be sized and positioned to not significantly alter a strength of the magnetic field within the magnetic circuit. Accordingly, top gap  906  may have a width that is small compared to a length of side magnet  404 . For example, a width of top gap  906  may be less than 10% of a length of side magnet  404 . Furthermore, top gap  906  may be located away from the densest region of magnetic flux in the magnetic circuit. For example, although a pair of top gaps  906  is shown as being located in the middle of the long sides of top plate  410 , the pair of top gaps  906  may instead be positioned at the corners  950  of top plate  410  away from side magnets  404  such that maximum top plate  410  material is maintained over side magnet  404 . Thus, a pair of top gaps  906  may separate top plate  410  into first and second portions that are electrically isolated from one another without affecting the magnetic circuit of audio speaker  104 . 
     Bottom plate  408  may also be split into portions that are electrically insulated from each other. For example bottom plate  408  may include a first bottom portion  908  physically separated from a second bottom portion  910  by a bottom gap  912 . Thus, first bottom portion  908  may be electrically insulated from second bottom portion  910 . Bottom gap  912  may be configured in a manner similar to top gap  906 , e.g., may include an air gap, a dielectric spacing component, or a dielectric coupling that physically connects first bottom portion  908  to second bottom portion  910  while electrically insulating the portions from each other. Also like top gap  906 , bottom gap  912  may be sized and positioned to not affect the magnetic circuit of audio speaker  104 . Accordingly, the magnet assembly of  FIG. 9  having top plate  410  and or bottom plate  408  split into several components may function magnetically in a manner similar to the magnet assembly illustrated in  FIG. 4 . 
     Referring to  FIG. 10 , a sectional view, taken about line A-A of  FIG. 3 , of an audio speaker is shown in accordance with an embodiment. Wire coil  414  suspended within air gap  412  may include first terminal  416  extending away from center magnet  402  toward top plate  410  in a first direction and second terminal  418  extending away from center magnet  402  toward top plate  410  in a different direction. More particularly, first terminal  416  may extend over first top portion  902  of top plate  410  and second terminal  418  may extend over second top portion  904  of top plate  410 . In an embodiment, first terminal  416  is in electrical contact with first top portion  902  and second terminal  418  is in electrical contact with second top portion  904 . For example, the terminals may be spot welded to the top surface of respective portions of top plate  410 . Thus, the electrical circuit of audio speaker  104  may pass through both first top portion  902  and second top portion  904 . Furthermore, as described above, first top portion  902  may be electrically insulated from second top portion  904  such that the electrical circuit does not short through top plate  410 , but rather, the electrical audio signal current passes between first terminal  416  and second terminal  418  through wire coil  414 . 
     In an embodiment, the electrically insulated portions of top plate  410  are electrically connected to respective portions of bottom plate  408 . First top portion  902  may be electrically connected to first bottom portion  908  through an electrical bridge  1002 . Similarly, second top portion  904  may be electrically connected to second bottom portion  910  through a respective electrical bridge  1002 . Electrical bridge  1002  may support and space top portions relative to respective bottom portions in a manner similar to yoke support  508  described above. Rather than insulating top plate  410  from bottom plate  408 , however, electrical bridge  1002  may be at least partly formed from a conductive material to provide an electrical path for electrical current to flow between top plate  410  and bottom plate  408  through electrical bridge  1002 . In an embodiment, top plate  410  and bottom plate  408  may be physically supported by frame  302 , and thus, electrical bridge  1002  may be a conductive wire that does not support the plates, but rather, is spot welded to the magnetic plates to provide electrical continuity between the plates. 
     Bottom plate  408 , which may be electrically connected to wire coil  414  through electrical bridge  1002  and top plate  410 , may also provide an electrical connection with external components. More particularly, bottom plate  408  may include an input and output contact for an electrical audio signal current from speaker driver circuit  802 . In an embodiment, a first bottom contact  1004  is disposed on first bottom portion  908  and a second bottom contact  1006  is disposed on second bottom portion  910 . The bottom contacts may be printed, sputtered, or otherwise formed on, or attached to, a surface of bottom plate  408  facing away from an internal volume of audio speaker  104 . Thus, first bottom contact  1004  and second bottom contact  1006  may be placed in electrical contact with external electrical components by simply placing audio speaker  104  onto the external electrical component. For example, audio speaker  104  may be mounted on a flexible printed circuit having conductive pads or a main logic board having spring contacts such that the bottom contacts of bottom plate  408  electrically contact the external conductive pads and/or spring contacts. Audio speaker  104  may then be secured relative to the external electrical component, e.g., by solder, screws, or other fasteners, to make a secure electrical contact for receiving an electrical audio signal supplied by the external electrical component. Thus, it will be appreciated that the bottom contacts on bottom plate  408  eliminate the requirement to route external leads into the internal volume of audio speaker  104 . By removing such external leads, audio speaker  104  may be further miniaturized. 
     Still referring to  FIG. 10 , audio speaker  104  may include an electrical circuit extending from first bottom contact  1004  through first bottom portion  908 , electrical bridge  1002 , and first top portion  902  into first terminal  416  of wire coil  414 . The electrical circuit may continue through wire coil  414  to second terminal  418  and into second top portion  904 . Furthermore, electrical current from second terminal  418  may pass through second top portion  904 , electrical bridge  1002 , and second bottom portion  910  to complete the electrical circuit at second bottom contact  1006 . Accordingly, wire coil  414  and several components of the magnet assembly of audio speaker  104  may form the electrical circuit of audio speaker  104 . As described above, an electrical circuit passing through the magnet assembly may essentially be split into halves, i.e., a first half (having first top portion  902  and first bottom portion  908 ) that is electrically insulated from a second half (having second top portion  904  and second bottom portion  910 ). Also as described above, the electrical circuit of audio speaker  104  that includes electrical paths passing through components of the magnet assembly may be electrically insulated from the permanent magnets of magnet assembly. 
     In an embodiment, center plate  406  and center magnet  402  are separated from top plate  410  portions by air gap  412 , and thus, center plate  406  and center magnet  402  are electrically insulated from top plate  410 . Center magnet  402  may, however, be disposed on bottom plate  408 . More particularly, center magnet  402  may be mounted on first bottom portion  908  and second bottom portion  910 , and center magnet  402  may extend over bottom gap  912  to form a bridge between first bottom portion  908  and second bottom portion  910 . To prevent an electrical short between first bottom portion  908  and second bottom portion  910  through center magnet  402 , a first insulating bonding layer  1008  may be disposed between center magnet  402  and the bottom plate  408  portions. First insulating bonding layer  1008  may be similar to insulating bonding layer  602  described above. That is, first insulating bonding layer  1008  may include one or more dielectric spacer to electrically insulate center magnet  402  from the bottom plate  408  portions. First insulating bonding layer  1008  may also include an adhesive to securely mount center magnet  402  on the bottom plate  408  portions. 
     Referring to  FIG. 11 , a sectional view, taken about line B-B of  FIG. 3 , of an audio speaker is shown in accordance with an embodiment. The illustrated section line B-B passes through bottom gap  912 , and thus, side magnets  404  and corresponding second top portions  904  are sectioned. An end view of second bottom portion  910  is shown, i.e., the section plane faces (but does not section) second bottom portion  910 . Center plate  406  and center magnet  402  may be electrically insulated from second bottom portion  910  by first insulating bonding layer  1008 , as described above. Thus, electrical shorting between second bottom portion  910  and first bottom portion  908  through center magnet  402  may be prevented. 
     Side magnet  404 , like center magnet  402 , may be mounted on one or more of the bottom plate  408  portions. More particularly, side magnet  404  may be mounted on first bottom portion  908  and second bottom portion  910  and extend over bottom gap  912  to form a bridge between first bottom portion  908  and second bottom portion  910 . Furthermore, side magnet  404  may be sandwiched between top plate  410  and bottom plate  408 , and thus, one or more portions of top plate  410  may be mounted on side magnet  404 . For example, first top portion  902  and second top portion  904  may be mounted on side magnet  404 . Accordingly, side magnet  404  may provide an electrical short path between portions of top plate  410 , between portions of bottom plate  408 , and/or between top plate  410  and bottom plate  408 . Side magnet  404  may, however, be electrically insulated from top plate  410  and bottom plate  408  to eliminate the electrical short paths. 
     In an embodiment, a second insulating bonding layer  1102  is disposed between side magnet  404  and bottom plate  408 . Second insulating bonding layer  1102  may be similar to insulating bonding layer  602  described above. That is, second insulating bonding layer  1102  may include one or more dielectric spacer, e.g., a first dielectric spacer and a second dielectric spacer, to electrically insulate side magnet  404  from the bottom plate  408  portions. Second insulating bonding layer  1102  may also include an adhesive to securely mount side magnet  404  on the bottom plate  408  portions. Separate second insulating bonding layers  1102  may be disposed beneath respective side magnets  404 , i.e., although an identical indicator is used for second insulating bonding layer  1102  beneath each side magnet  404  in  FIG. 11 , the bonding layers may or may not be applied in a same manufacturing operation. Thus, bottom plate  408  may be electrically insulated from the permanent magnets of the magnet assembly. That is, first insulating bonding layer  1008  and second insulating bonding layer  1102  may electrically insulate bottom plate  408  from center magnet  402  and side magnet  404 . 
     A third insulating bonding layer  1104  may be disposed between side magnet  404  and top plate  410 . Third insulating bonding layer  1104  may be similar to insulating bonding layer  602  described above. That is, third insulating bonding layer  1104  may include one or more dielectric spacers, e.g., a third dielectric spacer and a fourth dielectric spacer, to electrically insulate side magnet  404  from the top plate  410  portions. Third insulating bonding layer  1104  may also include an adhesive to securely mount the top plate  410  portions on side magnet  404 . Separate third insulating bonding layers  1104  may be disposed over respective side magnets  404 , i.e., although an identical numeral is used to identify third insulating bonding layer  1104  over each side magnet  404  in  FIG. 11 , the bonding layers may or may not be applied in a same manufacturing operation. Thus, top plate  410  may be electrically insulated from the permanent magnets of the magnet assembly. Third insulating bonding layer  1104  may electrically insulate top plate  410  from side magnet  404  and air gap  412  may electrically insulate top plate  410  from center magnet  402 . 
     Referring to  FIG. 12 , a top view of a portion of an audio speaker having a wire coil electrically connected to a magnet assembly is shown in accordance with an embodiment. The electrical current path through the magnet assembly may complete an electrical circuit with an external electronic components. For example, first bottom contact  1004  and second bottom contact  1006  may electrically connect to speaker driver circuit  802  through respective leads. The leads may be printed on a main logic board, for example, and speaker driver circuit  802  may be an audio driver amplifier that is also attached to the main logic board. Thus, speaker driver circuit  802  may receive audio signal  804  from electronic device  100  circuitry and amplify the signal to provide the electrical current that passes to audio speaker  104 . More particularly, the electrical current may be input to first bottom contact  1004  and output from second bottom contact  1006 , or vice versa. 
     The electrical path between each bottom contact and a respective terminal of wire coil  414  may be located outside of the densest portions of the magnetic field formed by the magnetic circuit of audio speaker  104 . For example, the electrical audio signal current may pass from first bottom contact  1004  through first bottom portion  908  and electrical bridge  1002  into first top portion  902  at a side location. The side location may be along a side of top plate  410  that is orthogonal to a side of top plate  410  over side magnet  404 . More particularly, the magnetic field may be focused in air gap  412  between center magnet  402  and side magnet  404  in a direction parallel to the long direction of top gap  906  and bottom gap  912 , and the electrical current may flow between first bottom contact  1004  and first terminal  416  at a location that is laterally offset from the magnetic flux. Similarly, second bottom contact  1006  and an electrical contact between second terminal  418  of wire coil  414  and second top portion  904  may be laterally offset from the magnetic flux. Thus, electrical current flowing through the magnet assembly of audio speaker  104  may not interfere with magnetic flux flowing through the magnet assembly. 
     The electrical audio signal current may pass into wire coil  414  through respective terminals. For example, first terminal  416  of wire coil  414  may be attached to first top portion  902  of top plate  410  at a first top contact  806 . In an embodiment, first top contact  806  includes a spot weld formed between first terminal  416  and a top surface of first top portion  902 . Thus, the electrical current may pass from first top portion  902  to first terminal  416  through the spot weld. First terminal  416  may be spot welded, however, to other surfaces of the magnet assembly. For example, first terminal  416  may be spot welded directly to first bottom portion  908 . Accordingly, rather than passing through electrical bridge  1002  and first top portion  902 , electrical current may pass from first bottom contact  1004  to first terminal  416  directly through first bottom portion  908 . 
     Second terminal  418  of wire coil  414  may be attached to second top portion  904  of top plate  410  in a manner similar to first terminal  416 . More particularly, second terminal  418  may be spot welded to the top surface of second top portion  904  at a second top contact  808 . Thus, the electrical current may pass from second top portion  904  to second terminal  418  through the spot weld. Second terminal  418  may be spot welded to other surfaces of the magnet assembly, however, such as second bottom portion  910 . 
     As described above, first top contact  806  and second top contact  808  may be laterally offset from side magnet  404  to separate the electrical current in the magnet assembly from the magnetic flux in the magnet assembly. As such, first top contact  806  may be located along a short length of first top portion  902  and second top contact  808  may be located along a short length of second top portion  904 . Center plate  406  and/or center magnet  402  may be located between the top contacts. For example, a line drawn between first top contact  806  and second top contact  808  may pass through or over center magnet  402 . Furthermore, in an embodiment, the line passing through the top contacts is orthogonal to a line that is aligned with the long direction of top gap  906  and/or bottom gap  912 . 
     Referring to  FIG. 13 , an exploded view of a portion of an audio speaker having a magnet assembly and a wire coil is shown in accordance with an embodiment. One or more of the side magnets  404  of the magnet assembly may be placed in direct contact with respective top and bottom portions without the need for an intermediate insulating bonding layer  602 . More particularly, the magnet assembly illustrated in  FIG. 13  may be similar to the magnet assembly illustrated in  FIG. 9  except that insulating bonding layers are not disposed between side magnet  404  and respective top and bottom plate portions. Instead, electrical shorting between portions of top plate  410  and portions of bottom plate  408  may be prevented by splitting side magnet  404  into several portions. 
     The magnet assembly may include top plate  410  segmented into first top portion  902  and second top portion  904 , and first top portion  902  may be electrically insulated from second top portion  904  by top gap  906 . Similarly, bottom plate  408  may be segmented into first bottom portion  908  and second bottom portion  910 , and first bottom portion  908  may be electrically insulated from second bottom portion  910  by bottom gap  912 . Side magnet  404  may be sandwiched between the top and bottom portions to form the magnetic circuit having a magnetic field focused in air gap  412 . More particularly, the magnetic flux of the magnetic field may traverse an air gap  412  between center plate  406  and top plate  410  portions to interact with an electrical audio signal current delivered through wire coil  414  suspended in air gap  412 . 
     Wire coil  414  may include first terminal  416  and second terminal  418 , which may be placed in electrical contact with respective first top portion  902  and second top portion  904  by spot welds, as described above. Thus, electrical current may pass through first top portion  902  and second top portion  904 . To prevent electrical shorting from first top portion  902  to second top portion  904  through side magnet  404 , side magnet  404  may be segmented into a first magnet portion  1302  and a second magnet portion  1304 . First magnet portion  1302  may be sandwiched between first top portion  902  and bottom plate  408 , e.g., first bottom portion  908 . Second magnet portion  1304  may be sandwiched between second top portion  904  and bottom plate  408 , e.g., second bottom portion  910 . The magnet portions may furthermore be separated by a magnet gap  1306 . Magnet gap  1306  may be configured in a manner similar to top gap  906  and/or bottom gap  912 , e.g., may include an air-filled void, a dielectric spacing component, or a dielectric coupling that physically connects first magnet portion  1302  to second magnet portion  1304  while electrically insulating the portions from each other. Thus, first magnet portion  1302  of side magnet  404  may be electrically insulated from second magnet portion  1304  of side magnet  404  by magnet gap  1306 . 
     In an embodiment, the magnet gap  1306  between magnet portions is aligned with one or more of top gap  906  or bottom gap  912  between respective top plate  410  and bottom plate  408  portions. For example, magnet gap  1306 , top gap  906 , and bottom gap  912 , may be air-filled voids placed in fluid communication between a top surface of top plate  410  and a bottom surface of bottom plate  408 . Thus, magnet gap  1306  may extend between top gap  906  and bottom gap  912  to form an isolation region between a first half of the magnet assembly electrically connected to first terminal  416  of wire coil  414  and a second half of the magnet assembly electrically connected to second terminal  418  of wire coil  414 . 
     Whereas magnet gap  1306  may create an electrical isolation region between halves of top plate  410  and/or bottom plate  408  without the inclusion of an intermediate insulating bonding layer, each magnet portion may provide a potential electrical path between a top portion and a respective bottom portion. Nonetheless, the electrical audio signal current may preferentially travel between bottom plate  408  and top plate  410  through electrical bridge  1002 . Furthermore, the electrical current may follow a path through top plate  410  from electrical bridge  1002  into wire coil  414  rather than traveling around top plate  410  and into the magnet portion. More particularly, electrical bridge  1002  may have a lower electrical resistance than the magnet portion to provide a preferential conductive path for the electrical current. Thus, although the magnet portion may provide a conductive path between top plate  410  and bottom plate  408 , the electrical current may follow another path of less resistance such that the electrical current in the electrical circuit of audio speaker  104  is routed along an electrical path that does not interfere with the magnetic field in the magnetic circuit of audio speaker  104 . 
     Although the foregoing specification has described routing an electrical audio signal current through a portion of a magnet assembly, e.g., top plate  410 , it will be appreciated that other electrical signals may be routed through one or more portions of the magnet assembly. For example, a capacitive displacement sensor may be used to detect displacement of diaphragm  304 , and a sensor signal from the capacitive displacement sensor may be routed through, e.g., center plate  406  or top plate  410 . More particularly, diaphragm  304  and top plate  410  may provide separate plate structures of the capacitive displacement sensor. An electrical charge may be applied to diaphragm  304  and top plate  410  by respective electrical paths. In the case of top plate  410 , electrical charge may be delivered through, e.g., printed circuit carrier  502 , to a conductive pad attached to top plate  410 . Accordingly, a change in capacitance between diaphragm  304  and top plate  410  may be detected by external circuitry connected to printed circuit carrier  502  to determine a displacement or relative position of diaphragm  304 . Other electrical signals may of course be routed through the magnet assembly in a similar manner. 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Metadata:
Filing Date: 20160901
Publication Date: 20200317
Grant Date: 20200317
Priority Date: 20150921
Inventors: VITT, Nikolas T.
WILK, CHRISTOPHER
PELLETIER, David M.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R9/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F7/0289", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F7/0289", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2400/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F7/0289", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 58283715