PATENT DOCUMENT

Publication Number: US-10708694-B2
Application Number: US-201715835365-A
Country: US
Kind Code: B2

Title: Continuous surround

Abstract:
A transducer assembly including a frame, a diaphragm positioned within the frame, a surround connecting the diaphragm to the frame, the surround having a corner section and a plurality of corrugations formed within the corner section, wherein each corrugation of the plurality of corrugations comprises a length dimension perpendicular to a line of maximum stress intersecting a radial axis of the corner section, a voice coil extending from one side of the diaphragm and a magnet assembly having a magnetic gap aligned with the voice coil.

Claims:
What is claimed is: 
     
       1. A transducer assembly comprising:
 a frame; 
 a diaphragm positioned within the frame; 
 a surround connecting the diaphragm to the frame, the surround having a corner section and a series of alternating ribs and furrows within the corner section, wherein the series of alternating ribs and furrows have a same continuous shape, and wherein each of the ribs or furrows comprises a length dimension perpendicular to a line of maximum stress intersecting a radial axis of the corner section; 
 a voice coil extending from one side of the diaphragm; and 
 a magnet assembly having a magnetic gap aligned with the voice coil. 
 
     
     
       2. The transducer assembly of  claim 1  wherein the transducer is a micro-speaker, and the line of maximum stress is parallel to a line tangential to an interior arcuate edge of the corner section. 
     
     
       3. The transducer assembly of  claim 1  wherein the line of maximum stress is perpendicular to the radial axis. 
     
     
       4. The transducer assembly of  claim 1  wherein the line of maximum stress is a region across the corner section determined to be subject to a maximum level of deformation stress based on a finite element analysis of the corner. 
     
     
       5. The transducer assembly of  claim 1  wherein the length dimension of each of the ribs or furrows is parallel to the radial axis. 
     
     
       6. The transducer assembly of  claim 1  wherein the radial axis bisects the corner section, and the line of maximum stress intersects the radial axis at a point that is between an inner edge and an outer edge of the corner section. 
     
     
       7. The transducer assembly of  claim 1  wherein the series of alternating ribs and furrows comprise a continuous second derivative and all other derivatives are continuous. 
     
     
       8. The transducer assembly of  claim 1  wherein each of the ribs or furrows extends from an inner edge to an outer edge of the corner section. 
     
     
       9. The transducer assembly of  claim 1  wherein the surround comprises a single, substantially solid membrane. 
     
     
       10. A surround for suspending a transducer diaphragm, the surround comprising:
 a first membrane section having a length dimension parallel to a first axis; 
 a second membrane section having a length dimension parallel to a second axis; 
 a corner membrane section at an intersection between the first axis of the first membrane section and the second axis of the second membrane section, wherein the first axis and the second axis intersect to form a ninety degree angle and the corner membrane section comprises an arcuate inner edge; and 
 a plurality of continuous corrugations within the corner membrane section, wherein the plurality of continuous corrugations comprise a series of alternating ribs and furrows having a same continuous shape, and each corrugation of the plurality of continuous corrugations comprises a length dimension perpendicular to a line tangential to the arcuate inner edge of the corner membrane section. 
 
     
     
       11. The surround of  claim 10  wherein each corrugation of the plurality of continuous corrugations comprises a curved cross-sectional shape. 
     
     
       12. The surround of  claim 10  wherein the length dimension of the plurality of continuous corrugations is perpendicular to a line of maximum stress that is parallel to the line tangential to the arcuate inner edge and intersects a center of the corner membrane section. 
     
     
       13. The surround of  claim 10  wherein the length dimension of each corrugation of the plurality of corrugations are parallel to one another. 
     
     
       14. The surround of  claim 10  wherein the length dimension of each corrugation of the plurality of corrugations runs from an inner edge to an outer edge of the corner membrane section. 
     
     
       15. A micro-speaker surround comprising:
 a membrane for connecting a diaphragm to an enclosure, the membrane having a first pair of parallel side sections, a second pair of parallel side sections, and a set of corner sections connecting the first pair of parallel side sections and the second pair of parallel sides sections; and 
 a plurality of continuous corrugations within each corner section of the set of corner sections, and wherein each of the corrugations of the plurality of continuous corrugations within each corner section have a length dimension perpendicular to a line of maximum stress intersecting a radial axis of their respective corner section and parallel to the radial axis. 
 
     
     
       16. The micro-speaker surround of  claim 15  wherein the first pair of parallel sides are longer than the second pair of parallel sides. 
     
     
       17. The micro-speaker surround of  claim 15  wherein the line of maximum stress intersects the radial axis at an angle of ninety degrees. 
     
     
       18. The micro-speaker surround of  claim 15  wherein the plurality of corrugations within adjacent corner sections are spaced a distance apart such that they do not overlap.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the earlier filing date of U.S. Provisional Patent Application No. 62/557,076, filed Sep. 11, 2017 and incorporated herein by reference. 
    
    
     FIELD 
     An embodiment of the invention is directed to a transducer surround with improved performance, more specifically a surround having continuous corner corrugations with a particular orientation to achieve improved linear stiffness and reduced fatigue. Other embodiments are also described and claimed. 
     BACKGROUND 
     Whether listening to an MP3 player while traveling, or to a high-fidelity stereo system at home, consumers are increasingly choosing intra-canal and intra-concha earphones for their listening pleasure. Both types of electro-acoustic transducer devices have a relatively low profile housing that contains a receiver or driver (an earpiece speaker). The low profile housing provides convenience for the wearer, while also providing very good sound quality. 
     These devices, however, do not have sufficient space to house high fidelity speakers. This is also true for portable personal computers such as laptop, notebook, and tablet computers, and, to a lesser extent, desktop personal computers with built-in speakers. Such devices typically require speaker enclosures or boxes that have a relatively low rise (e.g., height as defined along the z-axis) and small back volume, as compared to, for instance, stand alone high fidelity speakers and dedicated digital music systems for handheld media players. 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 low profile diaphragm (or sound radiating surface) assembly, including a sound radiating surface and a suspension (or surround), a voice coil suspended from the sound radiating surface and a magnet assembly positioned within an enclosure. The input of an electrical audio signal to the moving coil causes the sound radiating surface to vibrate axially thereby creating pressure waves outside the driver enclosure. The suspension surrounds and suspends the sound radiating surface within the enclosure and allows it to vibrate axially. 
     SUMMARY 
     An embodiment of the invention is a surround for suspending a diaphragm within a transducer which has a geometry that results in improved acoustic performance of the transducer. More specifically, the surround geometry results in improved linear stiffness with less likelihood of fatigue over time due to stress created by the pistonic (or z-axis) motion of the diaphragm. Representatively, in the case of a single suspension transducer, a surround performs many functionalities such as positioning the voice coil within the air gap of the magnet assembly, sealing the diaphragm to the enclosure to acoustically isolate the front side from the back side, contributing to the stiffness and influencing the resonance frequency of the transducer. Thus, during operation, it is important that the surround deform in a controlled way to, for example, prevent the voice coil from hitting rigid components within the transducer and to maintain the most linear stiffness possible within the displacement extremes of the diaphragm. The material stiffness and the stiffness defined by the surround geometry contribute to the stresses occurring within the material, and therefore play an important role in both fatigue and stiffness linearity. In the case of a micro-speaker, the surround may be rectangular to increase the radiating surface. Due to this rectangular shape, however, different sections of the surround have different deformation characteristics as the surround moves away from the rest position (e.g. due to diaphragm vibrations), which in turn, subjects certain areas of the surround to more stress than others. For example, the most complicated deformation occurs at the corners of the surround. In the corners, as the voice coil moves out of the air gap (coil-out direction), the highest point of the surround (in the case of a surround having an arcuate shape) tries to increase in radius and move away from the center of the surround. As the voice coil moves into the air gap (coil-in direction) the highest point of the surround tries to reduce in radius and moves toward the center of the surround. These radial changes introduce circumferential stresses over the surround geometry, and may lead to non linear behavior and fatigue development over time. The present invention reduces this non linear behavior and fatigue over time by introducing an improved corner geometry in which a number of continuous corrugations are formed in each corner of the surround and in a particular orientation with respect to a maximum stress line across each corner. 
     Representatively, in one embodiment, the invention is directed to a transducer having an enclosure separating a surrounding environment from an encased space, a diaphragm positioned within the encased space, a surround connecting the diaphragm to the enclosure, a voice coil extending from one side of the diaphragm and a magnet assembly having a magnetic gap (or air gap) aligned with the voice coil. In one embodiment, the transducer is an electroacoustic transducer such as a loudspeaker, more specifically, a micro-speaker. The term “micro-speaker” as used herein is intended to refer to a speaker having a size range (e.g., a diameter or longest dimension) of from about 10 mm to 75 mm, in some cases, within a size range of from 10 mm to 20 mm. Returning now to the surround, the surround may have a corner section and a plurality of corrugations formed within the corner section. Each corrugation of the plurality of corrugations may have a length dimension perpendicular to a line of maximum stress across the corner section. 
     More specifically, in one embodiment, the invention is directed to a transducer assembly including a frame, a diaphragm positioned within the frame, a surround connecting the diaphragm to the frame, a voice coil extending from one side of the diaphragm, and a magnet assembly having a magnetic gap aligned with the voice coil. The surround may include a corner section and a plurality of corrugations formed within the corner section. Each corrugation of the plurality of corrugations may have a length dimension perpendicular to a line of maximum stress intersecting a radial axis of the corner section. In some cases, the transducer is a micro-speaker, and the line of maximum stress is parallel to a line tangential to an interior arcuate edge of the corner section. In addition, in some embodiments, the line of maximum stress may be perpendicular to the radial axis. In addition, the line of maximum stress may be a region across the corner determined to be subject to a maximum level of deformation stress based on a finite element analysis of the surround corner. Still further, the length dimension of each corrugation may be parallel to the radial axis. The radial axis may be an axis that bisects the corner section, and the line of maximum stress intersects the radial axis at a point that is between an inner edge and an outer edge of the corner section. In some cases, the plurality of corrugations may include a continuous second derivative and all other derivatives are continuous. Each corrugation may extend from an inner edge to an outer edge of the corner section. The surround may be a single, substantially solid membrane. 
     In other embodiments, the invention is directed to a surround for suspending a transducer diaphragm. The surround may include a first membrane section having a length dimension parallel to a first axis, a second membrane section having a length dimension parallel to a second axis, a corner membrane section at an intersection between the first axis of the first membrane section and the second axis of the second membrane section, wherein the first axis and the second axis intersect to form a ninety degree angle and the corner membrane section comprises an arcuate inner edge, and a number of continuous corrugations within the corner membrane section. Each corrugation may have a length dimension perpendicular to a line tangential to the arcuate inner edge of the corner membrane section. In addition, the continuous corrugations may include a series of uninterrupted ribs and furrows. In addition, in some embodiments, the corrugations may have a curved cross-sectional shape. In addition, the length dimension of the corrugations may be perpendicular to a line of maximum stress that is parallel to the line tangential to the arcuate inner edge and intersects a center of the corner membrane section. Still further, the length dimensions of each corrugation may be parallel to one another, and in some cases, may run from an inner edge to an outer edge of the corner membrane section. 
     In still further embodiments, the invention is directed to a micro-speaker surround having a membrane for connecting a diaphragm to an enclosure, the membrane having a first pair of parallel side sections, a second pair of parallel side sections, and a set of corner sections connecting the first pair of parallel side sections and the second pair of parallel side sections; and a plurality of continuous corrugations within each of the corner sections of the set of corner sections, and wherein each of the corrugations of the plurality of continuous corrugations within each of the corner sections have a length dimension perpendicular to a line of maximum stress intersecting a radial axis of their respective corner section. In some cases, the first set of parallel sides may be longer than the second set of parallel sides. Still further, the line of maximum stress may intersect the radial axis at an angle of ninety degrees. In addition, the plurality of corrugations within adjacent corner sections may be spaced a distance apart such that they do not overlap. Still further, the plurality of corrugations within each of the corner sections may be parallel to the radial axis of their respective corner section. 
     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 assembly. 
         FIG. 2  illustrates a top plan view of one embodiment of a surround integrated within the transducer assembly of  FIG. 1 . 
         FIG. 3  illustrates a magnified top view of one embodiment of a corner of a surround. 
         FIG. 4  illustrates a schematic diagram of the deformation characteristics of the surround of  FIG. 3 . 
         FIG. 5  illustrates a magnified top plan view of one embodiment of a corner of a surround integrated within the transducer assembly of  FIG. 1 . 
         FIG. 6  illustrates one embodiment of a corrugation integrated within the surround of  FIG. 2 . 
         FIG. 7  illustrates a cross-sectional side view of a number of corrugations in the surround of  FIG. 2 . 
         FIG. 8  illustrates one embodiment of an electronic device in which a membrane as disclosed herein may be implemented. 
         FIG. 9  illustrates a simplified schematic view of one embodiment of an electronic device in which the membrane 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 terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like may be used herein for ease of description to describe one element&#39;s or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. 
     The terms “or” and “and/or” as used herein are to be interpreted as inclusive or meaning any one or any combination. Therefore, “A, B or C” or “A, B and/or C” mean “any of the following: A; B; C; A and B; A and C; B and C; A, B and C.” An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive. 
       FIG. 1  illustrates a cross sectional side view of one embodiment of a transducer. Transducer  100  may be any type of transducer for example, an electroacoustic transducer that uses a pressure sensitive diaphragm and circuitry to produce a sound in response to an electrical audio signal input. Representatively, transducer  100  may, for example, be a micro-speaker driver having a size range (e.g., a diameter or longest dimension) of from about 10 mm to 75 mm, in some cases, within a size range of from 10 mm to 20 mm. The electrical audio signal may be a music signal input to driver  100  by a sound source. The sound source may be any type of audio device capable of outputting an audio signal, for example, an audio electronic device such as a portable music player, home stereo system or home theater system capable of outputting an audio signal. 
     Transducer  100  may include a frame  102 , which may be part of a transducer enclosure or box whose height (or rise) and speaker back volume (also referred to as an acoustic chamber) are considered to be relatively small. For example, the enclosure height or rise may be in the range of about 1 millimeter (mm) to about 10 mm. The concepts described here, however, need not be limited to transducer enclosures whose rises are within these ranges. Each of the components of transducer  100 , for example components of a speaker assembly as will be discussed herein, may be positioned within, or otherwise connected to, frame  102 . 
     In one embodiment, one of the components of transducer  100  (e.g., speaker assembly components) positioned within frame  102  may include a sound radiating surface (SRS)  104 . The SRS  104  may also be referred to herein as an acoustic radiator, a sound radiator or a diaphragm. SRS  104  may be any type of flexible membrane capable of vibrating in response to an acoustic signal to produce acoustic or sound waves. For example, SRS  104  may include a top face  104 A, which generates sound to be output to a user, and a bottom face  104 B, which is acoustically isolated from the top face  104 A, so that any acoustic or sound waves generated by the bottom face  104 B do not interfere with those from the top face  104 A. The top face  104 A may be considered the “top” face because it faces, or includes a surface substantially parallel to, a top side of frame  102  (not shown). Similarly, the bottom face  104 B may be considered a “bottom” face because it faces, or includes a surface substantially parallel to, a bottom surface of frame  102 . Although shown substantially planar, in some embodiments, SRS  104  may have an out-of-plane region for geometric stiffening. SRS  104  may, for example, be made of a single layer of material, or multiple layers of material for increased stiffness. For example, SRS  104  made of a polyester material such as polyethylene naphthalate (PEN) or, one or more layers of a PEN thermofoil. 
     SRS  104  may be suspended within frame  102  by a suspension member  106 , also referred to herein as a suspension or surround. Suspension member  106  allows for a substantially vertical or pistonic movement of SRS  104 , that is in a substantially up and down direction as illustrated by arrow  124 , relative to fixed frame  102 . In one embodiment, suspension member  106  may have an inner edge  106 A connected to an outer edge of SRS  104  (e.g. by an adhesive or molded) and an outer edge  106 B attached to frame  102  to suspend SRS  104  within frame  102 . Suspension member  106  may be one continuous membrane which surrounds the SRS  104 . For example, in one embodiment, SRS  104  may have a rectangular or square shaped profile. Suspension member  106 , in turn, may be a similarly shaped square or rectangular membrane, but with an open center to accommodate SRS  104  such that it surrounds SRS  104 . In addition, suspension member  106  may have a corner geometry to improve non linearity by improving linear stiffness, as well as reduce fatigue, as will be discussed in more detail in reference to  FIG. 2  to  FIG. 7 . In addition, in some embodiments, suspension member  106  may have what is considered a “rolled” or “arcuate” configuration in that it has a curved region between the inner edge  106 A and outer edge  106 B. This curved configuration may allow 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  104 . It should be understood, however, that in some embodiments, suspension member  106  could be flat, or entirely planar. 
     In some embodiments, suspension member  106  may further provide a seal between SRS  104  and frame  102 . This seal may prevent acoustic cancellation and water ingress beyond (e.g., below) SRS  104  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., a voice coil). For example, suspension member  106  may be a membrane made of any compliant material that is sufficiently flexible to allow movement of SRS  104  in order to produce acoustic or sound waves. Representatively, suspension member  106  may be made of a polyester material such as polyethylene naphthalate (PEN), or a silicone. The term “membrane” as used herein is intended to refer to a relatively thin, pliable, sheet of material that can occupy an entire space between SRS  104  and frame  102 , and provide an acoustic and/or water tight seal. 
     Transducer  100  may further include a voice coil  110  positioned along a bottom face  104 B of SRS  104  (e.g., a face of SRS  104  facing magnet assembly  114 ). For example, in one embodiment, voice coil  110  may include a pre-wound coil assembly (which includes the wire coil held in its intended position by a lacquer or other adhesive material), which is wrapped around a bobbin or former  112 . The end of the former  112  may be directly attached to the bottom face  104 B of SRS  104 , such as by chemical bonding or the like. In another embodiment, former  112  may be omitted, and voice coil  110  may be directly attached to the bottom face  104 B of SRS  104 . In still further embodiments, the former  112  or voice coil  110  may instead be attached directly to the bottom face of suspension member  106 . In one embodiment, voice coil  110  may have a similar profile and shape to that of SRS  104 . For example, where SRS  104  has a square or rectangular shape, voice coil  110  may also have a similar shape. For example, voice coil  110  may have a substantially rectangular or square shape. Although not shown, voice coil  110  may further have electrical connections to a pair of terminals through which an input audio signal is received, in response to which voice coil  110  produces a changing magnetic field that interacts with the magnetic field produced by magnet assembly  114  for providing a driving mechanism for transducer  100 . 
     Magnet assembly  114  may be positioned along a bottom side of frame  102  or otherwise below SRS  104 . Magnet assembly  114  may include a magnet  116  (e.g., a NdFeB magnet), with a top plate  118  and a yoke  120  for guiding a magnetic circuit generated by magnet  116  across gap  122 . A one-magnet embodiment is shown here, although multi-magnet motors are also contemplated. 
     The specific features of suspension member  106  that allow for improved linear stiffness and fatigue will now be discussed in reference to  FIG. 2  to  FIG. 7 . Representatively,  FIG. 2  illustrates a top plan view of one embodiment of a suspension member of  FIG. 1 . From this view, it can be seen that suspension member  106  entirely surrounds SRS  104  and has a generally rectangular shaped profile. Representatively, suspension member  106  is made up of sections or sides  206 A,  206 B,  206 C and  206 D, which are connected, or otherwise joined, by corners  202 A,  202 B,  202 C and  202 D. Sides  206 A and  206 C may be substantially straight and parallel to each other. For example, sides  206 A and  206 C may each have a length dimension (L 1 ) which is parallel to lengthwise axes  204 A and  204 C as shown. In this aspect, sides  206 A and  206 C may be referred to herein as a set or pair of parallel sections or sides. Similarly, sides  206 B and  206 D may be substantially straight and parallel to each other. For example, sides  206 B and  206 D may have a length dimension (L 2 ) which is parallel to lengthwise axes  204 B and  204 D as shown. In this aspect, sides  206 B and  206 D may be referred to herein as a set or pair of parallel sections or sides. In addition, in the illustrated embodiment, sides  206 B and  206 D are longer than sides  206 A and  206 C such that suspension member  106  has a rectangular profile. In other embodiments, however, sides  206 B and  206 D may be shorter than sides  206 A and  206 C. In addition, in some embodiments, sides  206 B and  206 D may have a same length as sides  206 A and  206 C such that suspension member  106  has a square shaped profile. 
     Corners  202 A- 202 D may be considered the regions or portions of suspension member  106  where each of sides  206 A- 206 D intersect, or said another way, where each of axes  204 A- 204 D intersect. In some embodiments, axes  204 A and  204 C may be perpendicular to axes  204 B and  204 D such that a right or ninety degree angle is formed at their point of intersection, as shown. As previously discussed, due to these ninety degree angles, corners  202 A- 202 D can be subjected to particularly complicated deformation characteristics as SRS  104  vibrates, which in turn leads to increased stress at these regions. These complicated deformation characteristics will now be discussed in reference to  FIG. 3  and  FIG. 4 . 
     Representatively,  FIG. 3  is a magnified view of a representative corner  202 , and  FIG. 4  is a schematic illustration of the corner deformations described in reference to  FIG. 3 . In particular, the magnified corner view of  FIG. 3 , illustrates a curved surround corner  202  having what is considered the highest and/or center point  302 , and the corresponding circumference (c) and a radius (r) with respect to point  302 . During operation, as surround corner  202  moves up and down along a z-axis (e.g. z-axis as shown in  FIG. 4 ), the highest and/or center point  302  of corner  202  experiences tension in a radial direction along radius (r), and wants to move toward or away from the center of the radius illustrated by point  306  (e.g., along the x-axis as shown in  FIG. 4 ), and along the circumference (c). 
     More specifically, as shown in  FIG. 4 , in the resting position, suspension member  106  has a radius (r) and circumference (c), where the illustrated circumference point (c) corresponds to the highest point  302  illustrated in  FIG. 3 . When suspension member  106  moves in a downward direction along the z-axis as SRS  104  and voice coil  110  are moving toward magnet assembly  114  (also referred to as a coil-in direction), suspension member  106  wants to reduce in radius (r 1 ) (e.g., point  302  moves toward the center point  306  in  FIG. 3 ) and circumference (c 1 ). In addition, when suspension member  106  moves in an upward direction along the z-axis as SRS  104  and voice coil  110  are moving away from the magnet assembly  114  (also referred to as a coil-out direction), the suspension member  106  wants to increase in radius (r 2 ) (e.g., point  302  moves away from the center point  306 ) and circumference (c 2 ). As can be seen from the schematic illustration of  FIG. 4 , the change in radius between the resting radius (r) and the downward radius (r 1 ) (e.g., coil-in position) is less than the change in radius between the resting radius (r) and the upward radius (r 2 ) (e.g., coil-out position). 
     These radial and/or circumferential changes introduce stresses over the surround geometry, particularly in the circumferential direction, with the most stress being found along a maximum stress path across the corner. The maximum stress path or line can be calculated using a standard finite element analysis based on the selected material (having a particular elasticity), size of the corner and maximum deflection or excursion. It should further be understood that the maximum stress path or line referred to herein is calculated during manufacturing of the surround, and is therefore calculated prior to forming the “arcuate” or “rolled” region shown in  FIG. 1 . In other words, it is calculated based on a flat micro-speaker surround surface. In the case of a micro-speaker, however, even after this “rolled” region is formed, the region of maximum stress may still be described as a relatively straight line across the corner, despite the additional curvature. It is contemplated, however, that in other embodiments, a slightly curved maximum stress line (as illustrated by the dashed line  304 ) could be used to illustrate this region of maximum stress. For example, where the surround has a “rolled” or “arcuate” region and is larger than a surround dimensioned for use in a micro-speaker (e.g., greater distance between the inner and outer corner edges), the maximum stress line may be slightly curved. It should be understood, however, that even where the dimensions are changed and the line of maximum stress is curved or otherwise deviates from a straight line as shown, the corrugations should still be perpendicular to the maximum stress line. 
     In this aspect, the actual location of the region of maximum stress illustrated by line  304  can be defined in various ways. For example, in the case of a micro-speaker, the maximum stress path or line  304  of the suspension member corner  202  can be defined as a line of stress that crosses the center point  302  of the corner, and is parallel to, and offset from, a line  310  that is tangential to the interior arcuate surface  308  of corner  202 . The center point  302  can be defined, for example, as the region halfway between the inner and out edges of corner  202 , along radius (r). In addition, since the maximum stress path or line  304  may be parallel to the tangential line  310  of corner  202  as shown, the maximum stress path or line  304  may also be referred to herein as a tangential line which is offset with respect to the corner interior arcuate surface  308 . In addition, as can be seen from  FIG. 3 , the maximum stress path or line  304  may also be perpendicular to the diagonal or radial axis  312  of corner  202 , and offset from the interior arcuate surface  308 , and can therefore also be defined with respect to the radial axis  312 . For example, the maximum stress path or line  304  may be defined as a line across corner  202  that intersects the radial axis  312 , and in some cases bisects the radial axis  312  (or diagonal line), of corner  202  at an angle of ninety degrees. 
     These circumferential stresses along the maximum stress path or line  304  can be the main cause of non-linear behavior and fatigue development. To alleviate this stress, and in turn reduce non-linear behavior and fatigue development, a number of ribs or corrugations having a particular orientation with respect to this region of maximum stress are introduced into the suspension member corners. In particular, returning now to  FIG. 2 , each of corners  202 A- 202 D include a number of ribs or corrugations  208 . The ribs or corrugations  208  may extend in a lengthwise direction from an inner edge  106 A to an outer edge  106 B of each of corners  202 A- 202 D. The ribs or corrugations  208  may be confined to their respective corners such that corrugations  208  in adjacent corners do not overlap. For example, corrugations  208  within their respective corners  202 A- 202 D may be spaced apart by non-corrugated regions  210  within areas of sides  206 A- 206 B between the corners  202 A- 202 D. Each of corners  202 A- 202 D may include any number of corrugations suitable for improving linear behavior and fatigue, as discussed herein. 
     The particular orientation and structure of the corrugations will now be discussed in reference to  FIG. 5  to  FIG. 8 .  FIG. 5  illustrates a magnified top plan view of corner  202 B of  FIG. 2 . From this view, it can be seen that corner  202 B includes a number of corrugations  208  that run across an entire width dimension (W) of corner  202 B. In other words, from the inner edge  106 A to the outer edge  106 B of corner  202 B. Each of corrugations  208  may have a same orientation with respect to the maximum stress path or line  304  (and the tangential line  310 ). For example, each of corrugations  208  may run in a direction perpendicular to the maximum stress path or line  304 . More specifically, as can be seen from  FIG. 5 , each of corrugations  208  have a length axis or dimension (L) that intersects the maximum stress path or line  304  at a ninety degree angle. In addition, where the maximum stress path or line  304  is parallel to the tangential line  310  as previously discussed, the length axis or dimension (L) of corrugations  208  may also be defined as running in a direction perpendicular to, or being perpendicular to, tangential line  310 , or intersecting the tangential line  310  at an angle of ninety degrees. In addition, maximum stress path or line  304  and tangential line  310  intersect the diagonal or radial axis  312  of corner  202 . The diagonal or radial axis  312  may be considered the axis that extends in a diagonal or radial direction, and bisects corner  202  as shown in  FIG. 5 . The maximum stress path or line  304  and tangential line  310  may, in some embodiments, intersect radial axis  312  at an angle of ninety degrees. Thus, in some embodiments, the length dimension (L) of corrugations  208  may also be described as being perpendicular to a line (e.g., line  304  or line  310 ) intersecting the radial axis  312  of corner  202 . In addition, in some embodiments, corrugations  208  may be substantially straight structures that are parallel to one another, and/or parallel to radial axis  312 . In other words, corrugations  208  do not zig zag, bend, curve or otherwise have a tortious configuration along the length dimension (L). Still further, it should be noted that although the maximum stress path or line  304  is illustrated as a straight line, it could be slightly curved and corrugations  208  could be perpendicular to this slightly curved line. 
     It has been found that when the corrugations  208  are oriented perpendicular to the maximum stress line  304  at each corner as described herein, as opposed to at another angle, the corrugations  208  absorb the circumferential and radial deformations during diaphragm excursion more evenly. This, in turn, helps to restore linearity and reduce surround fatigue over time. For example,  FIG. 6  illustrates a magnified view of a corrugation  208  oriented perpendicular to the maximum stress line  304  and a corrugation  602  oriented at an angle other than ninety degrees (e.g., an obtuse or acute angle) with respect to the maximum stress line. As can be seen from  FIG. 6 , the perpendicularly oriented corrugation  208  absorbs the forces (illustrated by arrows  604 ) due to the radial and/or circumferential changes in the surround and deforms (e.g., contracts) relatively evenly along the length dimension (L). In contrast, in the case of the non-perpendicularly oriented corrugation  208 , these forces  604  cause the corrugation  208  to deform (e.g., contract) unevenly along the length dimension, almost in a twisting like manner. This type of corrugation deformation, in comparison to a relatively even deformation, is not as effective at absorbing surround changes in radius and/or circumference, and in turn not as effective against fatigue. 
     In addition to the orientation of corrugations  208 , it is further important in achieving a reduction in fatigue and improved linearity that corrugations  208  within each of their respective corners  202 A- 202 D are continuous and smooth. To illustrate this aspect,  FIG. 7  shows a magnified cross-sectional side view of a series of corrugations within a respective corner. Representatively, from this view, it can be seen that corrugations  208  are made up of a series of alternating ribs or ridges  702 A,  702 B,  702 C,  702 D,  702 E,  702 F, and  702 G, and furrows  704 A,  704 B,  704 C,  704 D,  704 E and  704 F. Each of the alternating ridges  702 A- 702 G and furrows  704 A- 704 F may be referred to as a corrugation, and may be considered continuous in that they have an immediate connection or spatial relationship, with no spaces or gaps in between adjacent structures. For example, the geometry of corrugations  208  may be defined as having a continuous second derivative and all other derivatives are continuous. In this aspect, corrugations  208  are also considered smooth structures and do not have any abrupt bends or corners where one transitions to the next. Said another way, the peaks and valleys formed by the ridges  702 A- 702 G and furrows  704 A- 704 F are curved, or otherwise formed by continuously bending lines, and have a radius, as previously discussed. It should further be understood, that although seven ridges  702 A- 702 G are illustrated, the surround corner may include any number of ridges, or corrugations. In addition, each surround corner may include the same number, or a different number of corrugations. In addition, it should be understood that although one particular surround corner, namely corner  202 B has been described in detail, the description with respect to corner  202 B applies to each of corners  202 A,  202 C, and  202 D. Thus, all of corners  202 A- 202 D will have corrugations  208  which are perpendicular to the maximum stress line and continuous. 
       FIG. 8  illustrates one embodiment of a simplified schematic view of one embodiment of an electronic device in which a transducer (e.g., a micro-speaker), such as that described herein, may be implemented. As seen in  FIG. 8 , the transducer 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  806 . 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 simplified schematic view of one embodiment of an electronic device in which a membrane as disclosed herein may be implemented. For example, an electronic device as discussed in reference to  FIG. 8  is an example of a system that can include some or all of the circuitry illustrated by electronic device  900 . 
     Electronic device  900  can include, for example, power supply  902 , storage  904 , signal processor  906 , memory  908 , processor  910 , communications circuitry  912 , and input/output circuitry  914 . In some embodiments, electronic device  900  can include more than one of each component of circuitry, but for the sake of simplicity, only one of each is shown in  FIG. 9 . In addition, one skilled in the art would appreciate that the functionality of certain components can be combined or omitted and that additional or less components, which are not shown in  FIG. 9 , can be included in, for example, device  900 . 
     Power supply  902  can provide power to the components of electronic device  900 . In some embodiments, power supply  902  can be coupled to a power grid such as, for example, a wall outlet. In some embodiments, power supply  902  can include one or more batteries for providing power to earphones, headphones or other type of electronic device associated with the headphone. As another example, power supply  902  can be configured to generate power from a natural source (e.g., solar power using solar cells). 
     Storage  904  can include, for example, a hard-drive, flash memory, cache, ROM, and/or RAM. Additionally, storage  904  can be local to and/or remote from electronic device  900 . For example, storage  904  can include an integrated storage medium, removable storage medium, storage space on a remote server, wireless storage medium, or any combination thereof. Furthermore, storage  904  can store data such as, for example, system data, user profile data, and any other relevant data. 
     Signal processor  906  can be, for example a digital signal processor, used for real-time processing of digital signals that are converted from analog signals by, for example, input/output circuitry  914 . After processing of the digital signals has been completed, the digital signals could then be converted back into analog signals. 
     Memory  908  can include any form of temporary memory such as RAM, buffers, and/or cache. Memory  908  can also be used for storing data used to operate electronic device applications (e.g., operation system instructions). 
     In addition to signal processor  906 , electronic device  900  can additionally contain general processor  910 . Processor  910  can be capable of interpreting system instructions and processing data. For example, processor  910  can be capable of executing instructions or programs such as system applications, firmware applications, and/or any other application. Additionally, processor  910  has the capability to execute instructions in order to communicate with any or all of the components of electronic device  900 . 
     Communications circuitry  912  may be any suitable communications circuitry operative to initiate a communications request, connect to a communications network, and/or to transmit communications data to one or more servers or devices within the communications network. For example, communications circuitry  912  may support one or more of Wi-Fi (e.g., a 802.11 protocol), Bluetooth®, high frequency systems, infrared, GSM, GSM plus EDGE, CDMA, or any other communication protocol and/or any combination thereof. 
     Input/output circuitry  914  can convert (and encode/decode, if necessary) analog signals and other signals (e.g., physical contact inputs, physical movements, analog audio signals, etc.) into digital data. Input/output circuitry  914  can also convert digital data into any other type of signal. The digital data can be provided to and received from processor  910 , storage  904 , memory  908 , signal processor  906 , or any other component of electronic device  900 . Input/output circuitry  914  can be used to interface with any suitable input or output devices, such as, for example, a microphone. Furthermore, electronic device  900  can include specialized input circuitry associated with input devices such as, for example, one or more proximity sensors, accelerometers, etc. Electronic device  900  can also include specialized output circuitry associated with output devices such as, for example, one or more speakers, earphones, etc. 
     Lastly, bus  916  can provide a data transfer path for transferring data to, from, or between processor  910 , storage  904 , memory  908 , communications circuitry  912 , and any other component included in electronic device  900 . Although bus  916  is illustrated as a single component in  FIG. 9 , one skilled in the art would appreciate that electronic device  900  may include one or more bus components. 
     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. The description is thus to be regarded as illustrative instead of limiting.

Metadata:
Filing Date: 20171207
Publication Date: 20200707
Grant Date: 20200707
Priority Date: 20170911
Inventors: ILKORUR, ONUR I.
SALVATTI, ALEXANDER V.
TOM, BONNIE W.
LEONHARDT, Oliver
WILK, CHRISTOPHER
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R7/18", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R7/18", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R7/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2307/207", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2231/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2231/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R7/18", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R2307/207", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R7/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/06", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65631928