PATENT DOCUMENT

Publication Number: US-10194248-B2
Application Number: US-201615048784-A
Country: US
Kind Code: B2

Title: Speaker with flex circuit acoustic radiator

Abstract:
A speaker assembly including a frame and a magnet assembly positioned within the frame. The magnet assembly may include a magnet and a top plate. The assembly further including a sound radiating surface suspended over the magnet assembly. The sound radiating surface includes a flexible circuit. A suspension suspending the sound radiating surface over the magnet assembly is further provided. The suspension may be over molded to the sound radiating surface and the frame. A voice coil extends from a bottom side of the sound radiating surface and electrically connects to the flexible circuit.

Claims:
What is claimed is: 
     
       1. A speaker assembly comprising:
 a frame; 
 a magnet assembly positioned within the frame; 
 a sound radiating surface suspended over the magnet assembly, the sound radiating surface comprising a flexible circuit that is electrically connected to an external wire that is external to the flexible circuit; 
 a suspension suspending the sound radiating surface over the magnet assembly; and 
 a voice coil extending from a bottom side of the sound radiating surface and having a voice coil lead wire that is electrically connected to the external wire by the flexible circuit, and wherein the voice coil lead wire and the external wire comprise a different material. 
 
     
     
       2. The speaker assembly of  claim 1  wherein the sound radiating surface is formed from the flexible circuit, and the flexible circuit is thermoformed to have an out-of-plane region dimensioned to geometrically stiffen the sound radiating surface. 
     
     
       3. The speaker assembly of  claim 1  wherein the voice coil lead wire comprises a lower tensile-strength material having less mass than the external wire. 
     
     
       4. The speaker assembly of  claim 1  wherein the flexible circuit comprises a metal layer and at least two polymer layers, and wherein at least one of the at least two polymer layers comprise a polyester. 
     
     
       5. The speaker assembly of  claim 1  wherein the magnet assembly further comprises a top plate having an open center and a cut-out region formed within at least one corner of the top plate. 
     
     
       6. The speaker assembly of  claim 1  wherein the suspension comprises silicone. 
     
     
       7. The speaker assembly of  claim 1  wherein the suspension is over molded to the sound radiating surface and the frame to form a seal between the sound radiating surface and the frame, and wherein the seal prevents water ingress past the sound radiating surface. 
     
     
       8. The speaker assembly of  claim 1  further comprising:
 a capacitive displacement sensor, the capacitive displacement sensor comprising a first electrode coupled to a portion of the frame positioned over the sound radiating surface and a second electrode formed within the flexible circuit of the sound radiating surface. 
 
     
     
       9. A speaker assembly comprising:
 a frame having a top frame member and a bottom frame member; 
 a magnet assembly coupled to the bottom frame member, the magnet assembly having a magnet and a top plate, the top plate having an open center region; 
 a sound radiating surface positioned over the magnet assembly, the sound radiating surface is formed by a flexible circuit having an out-of-plane region integrally formed therein, and wherein the out-of-plane region extends out of a plane of the sound radiating surface in a direction of the magnet assembly and is aligned with the open center region of the top plate; 
 a suspension suspending the sound radiating surface from the bottom frame member and over the magnet assembly; 
 a voice coil extending from a bottom face of the sound radiating surface and electrically connected to the flexible circuit; and 
 a capacitive displacement sensor comprising a first electrode coupled to the top frame member and positioned over the sound radiating surface, and a second electrode coupled to the sound radiating surface. 
 
     
     
       10. The speaker assembly of  claim 9  wherein the out-of-plane region comprises a dome shape. 
     
     
       11. The speaker assembly of  claim 9  wherein the suspension is over molded to the bottom frame member and the sound radiating surface. 
     
     
       12. The speaker assembly of  claim 9  wherein the suspension fluidly seals the sound radiating surface to the bottom frame member. 
     
     
       13. The speaker assembly of  claim 9  wherein the voice coil comprises a first wire electrically connecting the voice coil to the flexible circuit and the flexible circuit electrically connects the first wire to a second wire electrically connected to the flexible circuit, wherein the first wire comprises a lower tensile-strength material than the second wire. 
     
     
       14. A speaker assembly comprising:
 a frame; 
 a magnet assembly positioned within the frame; 
 a sound radiating surface suspended over the magnet assembly, the sound radiating surface is formed by a flexible circuit comprising a flexible material layer and a conductive trace formed on the flexible material layer; 
 a suspension suspending the sound radiating surface over the magnet assembly, the suspension is over molded to the sound radiating surface or the frame and seals the sound radiating surface to the frame; and 
 a voice coil extending from a bottom side of the sound radiating surface and electrically connected to the flexible circuit. 
 
     
     
       15. The speaker assembly of  claim 14  wherein the suspension is impervious to air such that it prevents the passage of air between the sound radiating surface and the frame. 
     
     
       16. The speaker assembly of  claim 14  wherein the suspension is impervious to water such that it prevents the passage of water between the sound radiating surface and the frame. 
     
     
       17. The speaker assembly of  claim 14  wherein the suspension is over molded to an outer edge of the sound radiating surface. 
     
     
       18. The speaker assembly of  claim 14  wherein the flexible circuit is thermoformed to have an out-of-plane region that bows out in a direction of the magnet assembly. 
     
     
       19. The speaker assembly of  claim 14  wherein the voice coil is electrically connected to an external wire coupled to a fixed speaker component by the flexible circuit. 
     
     
       20. The speaker assembly of  claim 14  further comprising:
 a capacitive displacement sensor, the capacitive displacement sensor comprising a first electrode coupled to a fixed portion of the frame positioned over the sound radiating surface and a second electrode formed within the flexible circuit of the sound radiating surface.

Description:
FIELD 
     This application relates generally to a speaker with an acoustic radiator made from a flexible circuit and, more specifically, to a speaker having an acoustic radiator made of a flexible circuit that is electrically connected to the speaker components. Other embodiments are also described and claimed. 
     BACKGROUND 
     In modern consumer electronics, audio capability is playing an increasingly larger role as improvements in digital audio signal processing and audio content delivery continue to happen. In this aspect, there is a wide range of consumer electronics devices that can benefit from improved audio performance. For instance, smart phones include, for example, electro-acoustic transducers such as speakerphone loudspeakers and earpiece receivers that can benefit from improved audio performance. Smart phones, however, do not have sufficient space to house much larger high fidelity sound output devices. This is also true for some portable personal computers such as laptop, notebook, and tablet computers, and, to a lesser extent, desktop personal computers with built-in speakers. Many of these devices use what are commonly referred to as “micro-speakers.” Micro-speakers are a miniaturized version of a loudspeaker, which use a moving coil motor to drive sound output. The moving coil motor may include a diaphragm, voice coil and magnet assembly positioned within a frame. Due to height limitations, the diaphragm is typically suspended within the frame by a single plane suspension system. In addition, electrical connections to the voice coil typically consist of wires running from the voice coil to other stationary components. The wires may flex as the radiator vibrates, which in turn, can lead to wire breakage and reliability issues in the field. 
     SUMMARY 
     This disclosure is directed to a transducer, for example a moving-coil speaker (e.g., a micro-speaker) that is water resistant, has high acoustic sensitivity, low tactility and incorporates a capacitive sensing element used for displacement detection of the acoustic radiator within the transducer. More specifically, some features of the speaker include an acoustic radiator or sound radiating surface (SRS) made from a flexible circuit (also commonly referred to as a flexible printed circuit board) with an over molded surround. The flexible circuit (or SRS) may, in turn, be used to connect the voice coil to external wiring (e.g., wiring external to the flexible circuit) and electronic components within the speaker. An advantage of using the flexible circuit (e.g., via circuitry therein) to provide electrical connections between the voice coil and wiring to external components, as opposed to the voice coil wiring itself extending directly to external components, is that the voice coil and the external wiring can be made of different materials that can improve an overall performance and reliability of the transducer. For example, the voice coil may be made of a relatively low-tensile strength and low mass material such as a copper-clad aluminum coil so that an overall mass of the voice coil is reduced. The external wiring, on the other hand, may be made of another type of wire material, for example, a higher-tensile strength material, such as a silver-copper alloy, that will not mechanically fatigue as it moves with respect to the SRS. In addition, the flexible circuit may be formed (e.g., thermoformed) to have a geometry that increases a stiffness of the radiator (and improves acoustic high-frequency performance of the speaker). In addition, to accommodate the moving assembly, a specially designed magnetic circuit is used which can accommodate the shape of the acoustic radiator and welded wires with minimal impact in motor strength. 
     More specifically, one embodiment is directed to a speaker assembly (e.g., a micro-speaker assembly) including a frame, a magnet assembly, a sound radiating surface, a suspension and a voice coil. The magnet assembly is positioned within the frame and may include a magnet and a top plate. The sound radiating surface is suspended over the magnet assembly and is formed from, or may include, a flexible circuit. The suspension suspends the sound radiating surface over the magnet assembly and is over molded to the sound radiating surface and the frame. The voice coil extends from a bottom side of the sound radiating surface and is electrically connected to the flexible circuit that may be used to form the sound radiating surface. In some cases, the flexible circuit is thermoformed to have an out-of-plane feature (e.g., a dome shaped region) dimensioned to geometrically stiffen the sound radiating surface, which in turn improves the sound radiating properties of the sound radiating surface. In addition, the flexible circuit (and in turn the sound radiating surface) may include a number of material layers. At least one of the material layers may include a conductive material, for example, a metal trace, metal layer, metal plate, or the like. The conductive material may, for example, be copper. In some embodiments, the flexible circuit (used to form the SRS) may include a metal layer and at least three polymer layers. At least one of the three polymer layers may include a polyester such as polyethylene naphthalate (PEN) or polyimide (PI) or polyethylene terephthalate (PET). In some embodiments, the top plate of the magnet assembly has an open center. The over molded suspension may be made of silicone. In addition, in some embodiments, the voice coil may include a voice coil lead wire electrically connected to a conductive trace in the flexible circuit, and the conductive trace in the flexible circuit serves to electrically connect the voice coil lead wire to an external wire. In some cases, the voice coil lead wire and the external wire may be made of different materials. For example, voice coil lead wire may be made of a lower tensile-strength material than the external wire. 
     The over molded suspension may form a seal between the sound radiating surface and the frame, and the seal prevents water ingress past the sound radiating surface. The speaker assembly may also include a capacitive displacement sensor having a first stationary electrode coupled to a portion of the frame positioned above or below, or both above and below, the sound radiating surface, and a second dynamic electrode formed within the flexible circuit of the sound radiating surface. 
     In another embodiment, the speaker assembly includes a frame having a top frame member and a bottom frame member. The assembly further includes a magnet assembly coupled to the bottom frame member. The magnet assembly may include a magnet and a top plate and the top plate may have an open center region. In addition, a sound radiating surface is positioned over the magnet assembly. The sound radiating surface may be formed from, or otherwise include, a flexible circuit having an out-of-plane region (e.g., concave, convex or dome shaped region) that is aligned with the open center region of the top plate. A suspension suspending the sound radiating surface from the bottom frame member and over the magnet assembly is also provided. In addition, a voice coil extends from a bottom side of the sound radiating surface and is electrically connected to the flexible circuit of the sound radiating surface. Finally, the assembly includes a capacitive displacement sensor having a first electrode coupled to the top frame member over the sound radiating surface, and a second electrode coupled to the sound radiating surface. 
     In some embodiments, the out-of-plane region is a concave region of the sound radiating surface that bows out in a direction of the magnet assembly. In addition, the suspension may be over molded to the bottom frame member and the sound radiating surface. The suspension may fluidly seal the sound radiating surface to the bottom frame member. The second electrode may include a metal plate formed within the flexible circuit of the sound radiating surface. 
     In another embodiment, a speaker assembly diaphragm is provided. The diaphragm includes a first material layer including a polymer material, a second material layer including a conductive material and a third material layer including a polymer material. The second material layer is between the first material layer and the third material layer. The first material layer and the third material layer may include a polyimide or a polyester. In some cases, both the first material layer and the third material layer include a polyester. In still further embodiments, both the first material layer and the third material layer include a polyimide. In some embodiments, the first material layer or the third material layer include polyethylene naphthalate. The diaphragm may further be stiffened with a fourth material layer made of a polyester, and the second material layer is a conductive layer. The conductive material of the second material layer may be a metal. The conductive material of the second material layer may be copper or aluminum. 
     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 
       The embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one. 
         FIG. 1  illustrates a cross-sectional side view of one embodiment of a transducer. 
         FIG. 2  illustrates a bottom plan view of the transducer of  FIG. 1  with the voice coil and magnet assembly omitted. 
         FIG. 3  illustrates a bottom plan view of the transducer of  FIG. 2  with the voice coil included. 
         FIG. 4  illustrates a bottom plan view of another embodiment of the transducer of  FIG. 1  with the magnet assembly omitted. 
         FIG. 5A  illustrates a bottom plan view of the sound radiating surface of the transducer of  FIG. 1 . 
         FIG. 5B  illustrates a cross-sectional side view of a portion of the sound radiating surface of  FIG. 5A . 
         FIG. 6A  illustrates a cross-sectional side view of the magnet assembly of the transducer of  FIG. 1 . 
         FIG. 6B  illustrates a bottom plan view of the top plate of the magnet assembly of  FIG. 6A . 
         FIG. 6C  illustrates a bottom plan view of the top plate of  FIG. 6B  assembled with the sound radiating surface and voice coil of  FIG. 1 . 
         FIG. 7  illustrates a process flow of one embodiment for forming the suspension of  FIG. 1 . 
         FIG. 8  illustrates one embodiment of a simplified schematic view of one embodiment of an electronic device in which one or more embodiments may be implemented. 
         FIG. 9  illustrates a block diagram of some of the constituent components of an embodiment of an electronic device in which one or more embodiments may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     In this section we shall explain several preferred embodiments of this invention with reference to the appended drawings. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not clearly defined, the scope of the invention is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments of the invention may be practiced without these details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this description. The terms “over”, “to”, and “on” as used herein may refer to a relative position of one feature with respect to other features. One feature “over” or “on” another feature or bonded “to” another feature may be directly in contact with the other feature or may have one or more intervening layers. In addition, the use of relative terms throughout the description, such as “top”, “above or “upper” and “bottom”, “under” or “lower” may denote a relative position or direction. For example, a “top edge”, “top end” or “top side” may be directed in a first axial direction and a “bottom edge”, “bottom end” or “bottom side” may be directed in a second direction opposite to the first axial direction. 
       FIG. 1  illustrates a cross-sectional side view of one embodiment of a transducer. Transducer  100  may be, for example, an electro-acoustic transducer that converts electrical signals into audible signals that can be output from a device within which transducer  100  is integrated. For example, transducer  100  may be a micro-speaker such as a speakerphone speaker or an earpiece receiver found within a smart phone, or other similar compact electronic device such as a laptop, notebook, or tablet computer. Transducer  100  may be enclosed within a housing or enclosure of the device within which it is integrated. In some embodiments, transducer  100  may be a 10 mm to 75 mm driver, or 10 mm to 20 mm driver (as measured along the diameter or longest length dimension), for example, a micro-speaker. 
     Transducer  100  may include a housing or frame  116 , which encloses all of the components of transducer  100 . Frame  116  may, in some cases, include a top frame member  116 B and a bottom frame member  116 A, between which a cavity for holding transducer components is formed. The top frame member  116 B and the bottom frame member  116 A may be welded together along their interfacing surfaces. 
     Transducer  100  may further include a sound radiating surface (SRS)  102 . The SRS  102  may also be referred to herein as an acoustic radiator, a sound radiator or a diaphragm. SRS  102  may be any type of flexible membrane (which may include a number of material layers) capable of vibrating in response to an acoustic signal to produce acoustic or sound waves. In this aspect, SRS  102  may include a top face  106 , which generates sound to be output to a user, and a bottom face  108 , which is acoustically isolated from the top face  106 , so that any acoustic or sound waves generated by the bottom face  108  do not interfere with those from the top face  106 . 
     SRS  102  may have an out-of-plane region  110 , for example, a concave dome or convex dome or other shaped region. In other words, the out-of-plane region  110  includes at least a portion which is in a different plane (e.g., a plane above or below) than the rest of SRS  102 . The out-of-plane region  110  may be within a center of the SRS  102  and be curved, or otherwise bow out, in a direction of the underlying magnet assembly  112 . The specific shape of the out-of-plane region  110  may be any shape that geometrically stiffens SRS  102  and improves a sound output from the SRS  102 . For example, the out-of-plane region may be dimensioned to stiffen the SRS  102  and improve acoustic high-frequency performance of transducer  100 . Still further, the out-of-plane region  110  may be dimensioned to stiffen the SRS  102  such that a breaking mode frequency of the SRS  102  is above a working range of transducer  100 . For example, out-of-plane region  110  may be a dome shaped region that bows out in a downward direction (e.g., toward magnet assembly  112 ). Alternatively, out-of-plane region  110  may be a dome shaped region that bows out in an upward direction (e.g., toward top frame member  116 A). The dome shaped region may, in some embodiments, include a flattened region (e.g., a disk shaped region) at its outermost portion, or be entirely curved. In addition, SRS  102  may include a stiffening material to materially stiffen SRS  102  in a manner that improves sound output, as will be discussed in more detail in reference to  FIGS. 5A-5B . 
     In addition, SRS  102  may include conductive layers, tracks, traces, pads or other features so that electrical connections with other transducer components can be made through SRS  102 . Representatively, in one embodiment, SRS  102  may include a number of material layers, at least one of which is a conductive layer. For example, SRS  102  may be made from a flexible circuit, having a number of preformed material layers, and thermoformed to have the desired SRS shape and size. For example, the flexible circuit may be heated, formed to the desired shape (e.g., a dome shape) using a mold and then cooled such that it retains the molded shape. The flexible circuit, or flex circuit or flexible printed circuit board (FPCB) as it is also commonly referred to, may be any flexible circuit having a number of material layers and circuitry formed within a flexible substrate whose shape may be changed upon application of an external force. This is in contrast to a “rigid” printed circuit board having two-dimensional and/or three-dimensional stability allowing no deformation, bending or an otherwise change in shape or profile of the structure upon application of an external force. It is further contemplated that in other embodiments, SRS  102  may, instead of being formed from a flexible circuit, be a diaphragm membrane having a flexible circuit mounted to an outer surface of the membrane. It should further be understood that any reference to a flexible circuit, flex circuit or FPCB herein is intended to include flexible circuits made by any technique, for example printing or any other techniques suitable for forming a flexible circuit which do not include a printing process. Further details regarding SRS  102  and the various material layers will be described in more detail in reference to  FIG. 5A - FIG. 5B . 
     Transducer  100  may also include a voice coil  114  positioned along a bottom face  108  of SRS  102  (e.g., a face of SRS  102  facing magnet assembly  112 ). For example, in one embodiment, voice coil  114  includes an upper end  124  and a lower end  126 . The upper end  124  may be directly attached to the bottom face  108  of SRS  102 , such as by chemical bonding or the like. In another embodiment, voice coil  114  may formed by a wire wrapped around a former or bobbin and the former or bobbin is directly attached to the bottom face  108  of SRS  102 . In one embodiment, voice coil  114  may have a similar profile and shape to that of SRS  102 . For example, where SRS  102  has a square, rectangular, circular or elliptical shape, voice coil  114  may also have a similar shape. For example, voice coil  114  may have a substantially rectangular, square, circular or racetrack shape. In addition, voice coil  114  may be made of a relatively low tension wire material (e.g., copper clad aluminum) which is electrically connected to a conductive layer or trace within SRS  102 , and the conductive layer or trace electrically connected to external wiring and components, as will be discussed in more detail in reference to  FIG. 3 - FIG. 4 . 
     SRS  102 , with voice coil  114  attached thereto, may be suspended within frame  116  by a suspension member  118 , also referred to herein as a suspension or surround. For example, the suspension member  118  may have an inner edge  128  that is molded along an outer edge  130  of SRS  102 . In addition, suspension member  118  may be over molded to the bottom frame member  116 A along its outer edge  132 . Alternatively, or in addition, the suspension member  118  may also be over molded to the top frame member  116 B, or both the top and bottom frame members  116 A,  116 B along the outer edge  132 . The suspension member  118  may be considered “molded” or “over molded” to the SRS  102  and/or the frame  116  in that suspension member  118  is formed (such as from liquid silicone) and chemically bonded to a surface of SRS  102  and/or frame  116  during an over molding process, for example, an injection molding process. In this aspect, a separate adhesive or bonding layer is not required to attach suspension member  118  to SRS  102  and/or frame  116 . In addition, molding suspension member  118  to SRS  102  and frame  116  creates an air-tight and water-tight seal between SRS  102  and frame  116 . This seal prevents acoustic cancellation and water ingress beyond (e.g., below) SRS  102  and therefore prevents any water, which may unintentionally enter transducer  100 , from damaging the various electronic components and circuitry associated with transducer  100  (e.g., voice coil  114 ). In this aspect, transducer  100  has some tolerance to water and/or may be considered water resistant in that water will not disable the transducer  100 . In one embodiment, the suspension member  118  may have what is considered a “rolled” configuration in that it has a concave or curved region between the inner edge  128  and outer edge  132  which allows for greater compliance in the z-direction (e.g., a direction perpendicular to the suspension member plane), and in turn, facilitates an up and down movement, also referred to as a vibration, of the SRS  102 . The curved region may curve or bow in a direction of the magnet assembly  112 . It should further be noted that although an over molded suspension member  118  is described, in other embodiments, where molding is not used, an adhesive or other bonding agent could be used to secure suspension member  118  to SRS  102  and/or frame  116 . 
     Transducer  100  may further include a magnet assembly  112 . Magnet assembly  112  may include a magnet  134  (e.g., a NdFeB magnet), with a top plate  136  and a yoke  138  for guiding a magnetic circuit generated by magnet  134 . Magnet assembly  112 , including magnet  134 , top plate  136  and yoke  138 , may be positioned below SRS  102 , for example, between SRS  102  and bottom frame member  116 A. For example, a bottom side  140  of magnet assembly  112  may be mounted to, or otherwise rest on such that it is in direct contact with, a top side  142  of bottom frame member  116 A. A one-magnet embodiment is shown here, although multi-magnet motors are also contemplated. 
     In one embodiment, magnet  134  may be a center magnet positioned entirely within an open center of voice coil  114 . In this aspect, magnet  134  may have a similar profile as voice coil  114 , for example, a square, a rectangular, a circular, or elliptical shape. Top plate  136  may be specially designed to accommodate an out-of-plane region  110  (e.g., a concave or dome shaped region) of SRS  102 . For example, top plate  136  may have a cut-out or opening  144  within its center that is aligned with the out-of-plane region  110  of SRS  102 . In this aspect, the additional space created below the out-of-plane region  110  allows SRS  102  to move or vibrate up and down (e.g., pistonically) without contacting top plate  136 . In this aspect, the opening  144  may have a similar size or area as the out-of-plane region  110 . Yoke  138  may have a substantially “U” shaped profile such that its sidewalls  146 ,  148  form the gap with magnet  134 , within which voice coil  114  is positioned. 
     Transducer  100  may further include a capacitive displacement sensor for sensing a displacement (e.g., vibration) of SRS  102 . Representatively, in one embodiment, a top or first electrode  150  may be positioned along a side of the top frame member  116 B facing SRS  102 . The first electrode  150  may be positioned such that, in the vertical alignment, it overlaps with SRS  102 . A second electrode  152  may be associated with SRS  102 . For example, in one embodiment, the second electrode  152  is formed by a conductive layer or plate within the SRS  102  (e.g., within the flexible circuit). In other embodiments, the second electrode  152  may be a separate component that is attached to a surface of SRS  102 , such as by an adhesive or chemical bonding. The first electrode  150  is in a fixed position while the second electrode  152  moves with SRS  102 . The electrodes  150 ,  152  may either be flat or formed with out-of-plane features. Therefore, during operation, the movement of SRS  102  creates a change in the amount of capacitance between the first electrode  150  and the second electrode  152 . This change in capacitance is sensed and translated into an electrical signal by, for example, an application-specific integrated circuit (ASIC) (not shown) electrically connected to the electrodes, for example, through a terminal  154  on frame  116  or elsewhere on transducer  100 . 
       FIG. 2  illustrates a bottom plan view of the transducer of  FIG. 1  with the voice coil and magnet assembly omitted. From this view, it can be seen that SRS  102 , which may be formed from a flexible circuit including traces or circuitry, may also include a conductive layer or plate  202  (as shown by dashed lines). The conductive layer or plate  202  may, for example, serve as the second electrode  152  formed within SRS  102  for capacitive sensing, as previously discussed in reference to  FIG. 1 . 
     Contact regions  204 ,  206  and  208  may further be formed, for example, within SRS  102  and exposed through the bottom side of SRS  102  to facilitate electrical connections with the circuitry and/or conductive plate  202  within SRS  102  (e.g., within the flexible circuit used to form SRS  102 ). For example, contact regions  204  and  206  may be contact pads (e.g., metal pads), which contact circuitry within SRS  102  and therefore can be used to electrically connect external wires  210 ,  212 , respectively, to the circuitry or other external components electrically connected to contact regions  204  and  206  (e.g., to drive current through the voice coil  114  to operate the transducer  100 ). Alternatively, or in addition, contact regions  204 ,  206  and/or  208  may have openings within a layer of SRS  102 , which expose the underlying conductive regions (e.g., plate  202  in the case of region  208 ) so that external wiring (e.g., wire  214 ) can be connected to them. In one embodiment, external wire  214  may be electrically connected to conductive plate  202  at contact region  208 , for example, to facilitate capacitive displacement sensing as previously discussed. Representatively, external wires  210 ,  212  and  214  may be welded to contact regions  204 ,  206 ,  208 , respectively, after the suspension member  118  is over molded to SRS  102 . Each of external wires  210 ,  212 ,  214  may be high-tensile strength wires that will not mechanically fatigue with the movement of SRS  102 . For example, wires  210 ,  212  and  214  may be silver copper alloy wires that have extra high-tension strength so that they will not break upon repeated movement of SRS  102 . Likewise, tinsel wire may be used. Each of external wires  210 ,  212 ,  214  may further be electrically connected to external components such as an ASIC, or other electronic component associated with transducer  100 , for example, by connecting them to the terminal  154  (or other terminals not shown) on frame  116  as previously discussed. For clarity, the three wires  210 ,  212 ,  214  are shown with a simple routing pattern. 
       FIG. 3  illustrates a bottom plan view of the transducer of  FIG. 2  with the voice coil included. From this view, it can be seen that once external wires  210 ,  212  and  214  are connected to contact regions  204 ,  206  and  208 , respectively, voice coil  114  is positioned over the external wires  210 ,  212  and  214  and attached (e.g., glued) to the bottom face  108  of SRS  102 . In other words, wires  210 ,  212  and  214  are sandwiched between SRS  102  and voice coil  114 . It should be noted that if voice coil  114  is positioned around a bobbin, the bobbin may be attached to the bottom face  108  of SRS  102 , instead of to the voice coil directly. The voice coil lead wires  302  and  304  are then welded to contact regions  204  and  206 , respectively. In some embodiments, a surface finishing step is performed to facilitate attachment of lead wires  302 ,  304  to contact regions  204 ,  206 , respectively. For example, a tin plating is applied to the contact regions  204 ,  206  (e.g., contact region pads) before welding on wires  302 ,  304 . 
     As previously discussed, voice coil lead wire  302  and external wire  210  are electrically connected at contact region  204 , and contact region  204  may provide an electrical connection to SRS  102  (e.g., via a pad connected to a conductive layer such as traces or circuitry within a flexible circuit used to form SRS  102 ). Therefore, SRS  102  (e.g., via circuitry or traces with the flexible circuit) may be used to provide an electrical connection between voice coil  114  and external wire  210 . Similarly, voice coil lead wire  304  and external wire  212  are electrically connected at contact region  206 , and contact region  206  may provide an electrical connection to SRS  102  (e.g., via a pad connected to circuitry or traces within the flexible circuit used to form SRS  102 ). Therefore, SRS  102  (via the flexible circuit) may be used to provide an electrical connection between voice coil  114  and external wire  212 . In other words, in one embodiment, the voice coil current is conducted by a conductive trace or layer of the flex circuit that constitutes the SRS  102 . The SRS  102  formed from the flexible circuit as previously discussed therefore provides an advantage over an SRS not formed from a flexible circuit in that it can be used to electrically connect the voice coil  114  to external wires at contact regions, or route electrical connections between contact regions for the voice coil  114  and contact regions for the external wires, as shown in  FIG. 4 . The external wires  210 ,  212 , in turn, may be used to electrically connect the voice coil lead wires  302 ,  304  to other circuitry or other electronic components associated with transducer  100  to help drive operation of the transducer  100 . 
     In addition, it should be understood that because the voice coil lead wires  302 ,  304  are welded directly to the SRS  102  and then wires  210 ,  212  are used to electrically connect voice coil lead wires  302 ,  304  to, for example, another stationary member, there is minimal flexing of lead wires  302 ,  304  when the SRS  102  moves. As a result, the wire forming voice coil  114  can be made of a lower tension or tensile-strength material with less mass than that of wires  210 ,  212 . This, in turn, reduces an overall mass of the SRS  102 /voice coil  114  assembly. Reducing the mass of the SRS  102 /voice coil  114  assembly may improve acoustic sensitivity and/or reduce unwanted transmitted forces (e.g., a user feeling the vibration of the SRS  102 ), which may occur in high powered transducers. For example, voice coil  114  can be made from a copper clad aluminum (CCA, 15-40% ratio) wire which reduces the mass of voice coil  114  and in turn the output of unwanted vibrational forces from transducer  100 . Wires  210 ,  212 , on the other hand, can be made of a higher tension or tensile strength material, for example, silver-copper alloy, as previously discussed. It should further be noted that external wire  214  may also be made of a similarly high tensile-strength material as wires  210 ,  212 . It should further be understood that using a higher-tensile strength material for external wires  210 ,  212  and  214  (in comparison to that of voice coil  114 ) improves the reliability of the transducer  100  as previously discussed, while still achieving a low mass SRS  102 /voice coil  114  assembly. 
       FIG. 4  illustrates a bottom plan view of another embodiment of the transducer of  FIG. 1  with the magnet assembly omitted. The embodiment of  FIG. 4  is substantially similar to that of  FIG. 3 , except in this case, each of wires  210 ,  212  and  214  and voice coil lead wires  302 ,  304  are electrically connected to different contact regions and the contact regions are moved outside of voice coil  114 . It should be understood that moving the contact regions outside of the voice coil  114  reduces the number of cut-outs that may need to be formed in the top plate of the magnet assembly to accommodate electrical connections with the contact regions (see  FIG. 6 ). Representatively, in this embodiment, SRS  102  includes five contact regions, namely, contact regions  204  and  206  positioned outside, or concentrically outward, to voice coil  114 , similar to those previously discussed regarding  FIG. 3 , and additional contact regions  402 ,  404  and  406  also positioned outside, or concentrically outward, of voice coil  114 , near an edge of SRS  102 . Voice coil lead wires  302 ,  304  may be electrically connected (e.g., welded) to contact regions  204 ,  206 , respectively, as previously discussed, while wires  210 ,  212  and  214  are electrically connected (e.g., welded) to contact regions  402 ,  404  and  406 , respectively. In addition, a trace  408 , or other similar electrical connector may be formed within SRS  102  (e.g., within the flexible circuit used to form SRS  102 ), between conductive plate  202  and contact region  406 , to maintain an electrical connection between conductive plate  202  and wire  214 . Similarly, there may be a trace  410  formed between contact regions  204  and  402  and a trace  412  formed between contact regions  206  and  404 , for electrically connecting the regions with one another. Each of the contact regions  204 ,  206 ,  402 ,  404 ,  406  may include (or be) pads connected to traces or conductive regions within SRS  102 , or be the internal conductive regions exposed through openings formed within the surface of SRS  102 , so that voice coil lead wires  302 ,  304  and external wires  210 ,  212 ,  214  may be electrically connected to a respective one of the contact regions. 
       FIG. 5A  illustrates a bottom plan view of the SRS of the transducer of  FIG. 1 . SRS  102  is the same as SRS  102  described in reference to  FIG. 2 - FIG. 3 , in that it includes conductive plate  202  and contact regions  204 ,  206  and  208 . As previously discussed, SRS  102  may, for example, be formed from a flexible circuit including a number of material layers. The various material layers will now be described in reference to  FIG. 5B , which is a cross-sectional side view of portion B (shown in dashed lines) in  FIG. 5A . 
     In particular, it can be seen from  FIG. 5B  that SRS  102  includes a cover layer  502 , a conductive layer  504  and a stiffener layer  506 . One or more of cover layer  502 , conductive layer  504  and/or stiffener layer  506  may be preformed layers within the flexible circuit, which as previously discussed, is thermoformed to achieve the desired SRS  102  configuration. The cover layer  502  may be made up of one or more material layers, which serve as a base layer for the overall stack up of material layers forming the SRS  102 . The conductive layer  504  may be made up of one or more material layers, at least one of which is made of a conductive material, which provides for electrical connections with SRS  102 . For example, the conductive layer may form the conductive plate  202  shown in  FIG. 5A , as previously discussed. In addition, although not shown, the conductive layer  504  may include trace  410  that electrically connects contact region  204  to contact region  402 , trace  412  that electrically connects contact region  206  to contact region  404 , and trace  408  to electrically connects plate  202  to pad  406 , as previously discussed in reference to  FIG. 4 . The stiffener layer  506  may be made of one or more layers of stiffening material that can provide material stiffness to SRS  102 . In addition, although not shown, conductive traces, tracks, pads or other components for providing electrical connections through the various layers may also be provided. 
     Referring now to each layer in more detail, cover layer  502  may form an outer surface of SRS  102  and include a polymer layer  508 . An adhesive layer  510  may optionally be provided for attaching the polymer layer  508  to conductive layer  504 . The polymer layer  508  may, for example, be a layer of polyester or polyimide material. For example, the stiffener layer  506  may be made of a polyester such as polyethylene naphthalate (PEN). It should be noted that although not specifically designed for this purpose, the polymer layer  508  may also provide some material stiffness to the SRS  102 . The adhesive layer  510  may be made of any type of adhesive material suitable for attaching one layer to another, for example, a glue or the like. The cover layer  502  may further include a cut-out or opening  522  to allow for a contact pad  520  (e.g., contact region  208 ) to electrically connect to conductive layer  504 . In addition, although not shown in this view, the cover layer  502  may also have cutouts for contact regions  204  and  206 . It is further noted that with respect to contact regions  204  and  206 , any corresponding pad should not contact the metal layer  512  of conductive layer  504  (or at least the portion of metal layer  512  that makes up plate  202 ). 
     The conductive layer  504  may be stacked on top of the cover layer  502  and include a metal layer  512  and a polymer layer  514 . The metal layer  512  is attached to the underlying polymer layer  508  of cover layer  502  by the previously discussed optional adhesive layer  510 . The metal layer  512  may be formed of any type of metal material, for example copper or aluminum, a metal alloy, or other similar material having metal disposed therein (e.g., metal particles). For example, in one embodiment, the metal layer  512  is a copper plate, which forms plate  202  shown in  FIG. 5A . The polymer layer  514  may include a layer of polyester or polyimide material. For example, the polymer layer  514  may be made of a polyimide such as PI. It should be noted that although not specifically designed for this purpose, the metal layer  512  and polymer layer  514  may also provide some material stiffness to the SRS  102 . In addition, in some cases, the metal layer  512  is laminated with the polymer layer  514 . For example, the metal layer  512  may be composed of a layer of copper laminated with PEN. 
     The stiffener layer  506  may be stacked on top of the conductive layer  504  and include a polymer layer  518  attached to the conductive layer  504  by an optional adhesive layer  516 . The polymer layer  518  may be made of any polymer material suitable for providing mechanical stiffness to SRS  102 . For example, the polymer layer  518  may be made of a polyester such as PEN. In addition, a thickness of polymer layer  518  may be specifically selected to further control its stiffening properties. For example, the polymer layer  518  may be anywhere from 5 to 100 microns, more specifically about 50 microns. The polymer layer  518  is directly attached to polymer layer  514  of conductive layer  504  with optional adhesive layer  516 . It should further be noted that the entire stack shown in  FIG. 5B  (e.g., stiffener layer  506 , conductive layer  504  and cover layer  502 ) are part of a flexible circuit that can optionally be thermoformed to be concave or convex as previously discussed. 
     It is further noted that in keeping with the desire to maintain a relatively low profile transducer, a combined thickness of all the material layers forming SRS  102  may be less than 120 microns, for example, less than 110 microns, or between 15 microns and 120 microns, or from about 100 microns and 120 microns. In this aspect, each of layers  508 ,  510 ,  512 ,  514 ,  516  and  518  may vary within a range of from about 5 microns to about 100 microns. For example, in some embodiments, the polymer layers  508 ,  514  and  518  may have a thickness of from about 8 microns to about 50 microns, for example, from about 12 microns to 40 microns, for example, from 12.5 microns to 30 microns, or from 15 microns to 20 microns. The metal layer  512 , in some cases, may have a thickness of from about 8 microns to 50 microns, for example, from about 12 microns to 40 microns, or from about 12.5 microns to 30 microns, or from 15 microns to 20 microns. The optional adhesive layers  510 ,  516  may have a thickness of from about 10 microns to 50 microns, for example, from 12.5 microns to 30 microns, or from 15 microns to 20 microns. 
       FIG. 6A  illustrates a cross-sectional side view of the magnet assembly of the transducer of  FIG. 1 . Magnet assembly  112  is the same as the magnet assembly described in reference to  FIG. 1  in that it includes magnet  134 , top plate  136  and yoke  138 . In addition, top plate  136  includes opening  144  to accommodate the concave region of the overlying SRS. The opening  144 , and other aspects of the top plate  136  can be seen more clearly from the bottom plan view of the top plate shown in  FIG. 6B . In particular, from this view, it can be seen that opening  144  is within a center of top plate  136  and formed entirely through the plate. In addition, it can be seen that the corners of top plate  136  are cut-out such that top plate includes one or more corner cut-out regions  602 ,  604 ,  606  and  608 . As can be seen from  FIG. 6C , which is a bottom plan view of the top plate of  FIG. 6B  with the SRS  102  of  FIG. 1  included, the corner cut-out regions  602 ,  604  and  606  provide openings or recessed regions within corners of top plate  136  that expose contact regions  204 ,  206  and  208  so that the external wires can be connected to contact regions  204 ,  206  and  208 . The cut-out regions  602 ,  604  and  606  may be of any size and shape suitable for accommodating access to the contact regions  204 ,  206  and  208 . Representatively, one or more of the cut-out regions  602 ,  604 ,  606  and  608  may form chamfered regions on the inside of a corner, on the outside of the corner, or both, of the top plate  136 . The contour of a chamfered portion (that joins with, or is the transition between, the two sides of the top plate  136 ) may be entirely straight, or it may be curved. In addition, it can be seen that opening  144  has a similar profile to that the out-of-plane region  110  of SRS  102 , for example, a square shaped profile, in this case. It should further be understood that while in  FIG. 6B  and  FIG. 6C , top plate  136  is shown having four cut-out regions  602 ,  604 ,  606  and  608 , fewer cut-out regions may be used depending upon the number of contact regions. For example, in one embodiment, cut-out region  608  may be omitted such that only three corners of top plate  136  include cut-out regions  602 ,  604  and  606 . 
       FIG. 7  illustrates a process flow of one embodiment for forming the suspension member of  FIG. 1 . In particular, the over molding process  700  includes the process operation of placing the transducer frame (e.g., bottom frame member  116 A) and the SRS (e.g., SRS  102 ) into a mold cavity (block  702 ). The mold cavity may be dimensioned to hold the frame and the SRS in the desired position, and have the desired suspension member shape. Next, the suspension member material may be loaded into the mold cavity such that it covers the outer edge of the SRS and inner surfaces of the frame (block  704 ). In some cases, the suspension member material is a silicone material that is melted prior to loading into the mold such that it is injected in liquid form. Once the material is loaded, a pressure is applied (such as by a mold top member) to force the suspension member material to be molded into the desired shape, and to the frame and SRS (block  706 ). The suspension member material is then solidified (such as by cooling) to form a suspension member (e.g., suspension member  118 ), which is over molded to the SRS and frame. The mold can then be opened and the frame and SRS, with the suspension member over molded thereto, removed for further assembly of the other transducer components thereto (e.g., voice coil, magnet assembly and wiring). 
       FIG. 8  illustrates one embodiment of a simplified schematic view of one embodiment of an electronic device in which a speaker assembly, such as that described herein, may be implemented. As seen in  FIG. 8 , the speaker may be integrated within a consumer electronic device  802  such as a smart phone with which a user can conduct a call with a far-end user of a communications device  804  over a wireless communications network; in another example, the speaker may be integrated within the housing of a tablet computer. These are just two examples of where the speaker described herein may be used, it is contemplated, however, that the speaker may be used with any type of electronic device in which a transducer, for example, a loudspeaker or microphone, is desired, for example, a tablet computer, a desk top computing device or other display device. 
       FIG. 9  illustrates a block diagram of some of the constituent components of an embodiment of an electronic device in which one or more embodiments may be implemented. Device  900  may be any one of several different types of consumer electronic devices. For example, the device  900  may be any transducer-equipped mobile device, such as a cellular phone, a smart phone, a media player, or a tablet-like portable computer. 
     In this aspect, electronic device  900  includes a processor  912  that interacts with camera circuitry  906 , motion sensor  904 , storage  908 , memory  914 , display  922 , and user input interface  924 . Main processor  912  may also interact with communications circuitry  902 , primary power source  910 , speaker  918  and microphone  920 . Speaker  918  may be a microspeaker such as that described in reference to  FIG. 1 . The various components of the electronic device  900  may be digitally interconnected and used or managed by a software stack being executed by the processor  912 . Many of the components shown or described here may be implemented as one or more dedicated hardware units and/or a programmed processor (software being executed by a processor, e.g., the processor  912 ). 
     The processor  912  controls the overall operation of the device  900  by performing some or all of the operations of one or more applications or operating system programs implemented on the device  900 , by executing instructions for it (software code and data) that may be found in the storage  908 . The processor  912  may, for example, drive the display  922  and receive user inputs through the user input interface  924  (which may be integrated with the display  922  as part of a single, touch sensitive display panel). In addition, processor  912  may send an audio signal to speaker  918  to facilitate operation of speaker  918 . 
     Storage  908  provides a relatively large amount of “permanent” data storage, using nonvolatile solid state memory (e.g., flash storage) and/or a kinetic nonvolatile storage device (e.g., rotating magnetic disk drive). Storage  908  may include both local storage and storage space on a remote server. Storage  908  may store data as well as software components that control and manage, at a higher level, the different functions of the device  900 . 
     In addition to storage  908 , there may be memory  914 , also referred to as main memory or program memory, which provides relatively fast access to stored code and data that is being executed by the processor  912 . Memory  914  may include solid state random access memory (RAM), e.g., static RAM or dynamic RAM. There may be one or more processors, e.g., processor  912 , that run or execute various software programs, modules, or sets of instructions (e.g., applications) that, while stored permanently in the storage  908 , have been transferred to the memory  914  for execution, to perform the various functions described above. 
     The device  900  may include communications circuitry  902 . Communications circuitry  902  may include components used for wired or wireless communications, such as two-way conversations and data transfers. For example, communications circuitry  902  may include RF communications circuitry that is coupled to an antenna, so that the user of the device  900  can place or receive a call through a wireless communications network. The RF communications circuitry may include a RF transceiver and a cellular baseband processor to enable the call through a cellular network. For example, communications circuitry  902  may include Wi-Fi communications circuitry so that the user of the device  900  may place or initiate a call using voice over Internet Protocol (VOIP) connection, transfer data through a wireless local area network. 
     The device may include a microphone  920 . Microphone  920  may be an acoustic-to-electric transducer or sensor that converts sound in air into an electrical signal. The microphone circuitry may be electrically connected to processor  912  and power source  910  to facilitate the microphone operation (e.g., tilting). 
     The device  900  may include a motion sensor  904 , also referred to as an inertial sensor, that may be used to detect movement of the device  900 . The motion sensor  904  may include a position, orientation, or movement (POM) sensor, such as an accelerometer, a gyroscope, a light sensor, an infrared (IR) sensor, a proximity sensor, a capacitive proximity sensor, an acoustic sensor, a sonic or sonar sensor, a radar sensor, an image sensor, a video sensor, a global positioning (GPS) detector, an RF or acoustic doppler detector, a compass, a magnetometer, or other like sensor. For example, the motion sensor  904  may be a light sensor that detects movement or absence of movement of the device  900 , by detecting the intensity of ambient light or a sudden change in the intensity of ambient light. The motion sensor  904  generates a signal based on at least one of a position, orientation, and movement of the device  900 . The signal may include the character of the motion, such as acceleration, velocity, direction, directional change, duration, amplitude, frequency, or any other characterization of movement. The processor  912  receives the sensor signal and controls one or more operations of the device  900  based in part on the sensor signal. 
     The device  900  also includes camera circuitry  906  that implements the digital camera functionality of the device  900 . One or more solid state image sensors are built into the device  900 , and each may be located at a focal plane of an optical system that includes a respective lens. An optical image of a scene within the camera&#39;s field of view is formed on the image sensor, and the sensor responds by capturing the scene in the form of a digital image or picture consisting of pixels that may then be stored in storage  908 . The camera circuitry  906  may also be used to capture video images of a scene. 
     Device  900  also includes primary power source  910 , such as a built in battery, as a primary power supply. 
     While certain embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that the invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. For example, the various speaker components described herein (e.g., diaphragm with flexible PCB, over molded suspension member, magnet top member with an opening, capacitive sensor, etc.) could be used in an acoustic-to-electric transducer or other sensor that converts sound in air into an electrical signal, such as for example, a microphone. The description is thus to be regarded as illustrative instead of limiting.

Metadata:
Filing Date: 20160219
Publication Date: 20190129
Grant Date: 20190129
Priority Date: 20160219
Inventors: GRAZIAN, ANTHONY P.
WILK, CHRISTOPHER
TAO, HONGDAN
PORTER, SCOTT P
ASFAW, MICHAEL
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R29/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R7/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R31/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R7/125", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2307/025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R31/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R31/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R7/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R7/125", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2307/025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R7/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2307/025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R29/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R7/125", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 59590114