PATENT DOCUMENT

Publication Number: US-9762997-B2
Application Number: US-201514975171-A
Country: US
Kind Code: B2

Title: Mobile device acoustic divider

Abstract:
A mobile communication device having an acoustic divider for minimizing acoustic coupling is disclosed. The mobile communication device includes a housing having an outer surface and internal sidewalls. The outer surface and internal sidewalls define a void disposed at and below the outer surface of the housing. The mobile communication device includes a receiver disposed within the housing and below a first portion of the void, and a microphone disposed within the housing and below a second portion of the void. An acoustic divider is disposed within the void and laterally disposed between the receiver and the microphone. The acoustic divider acoustically isolates the first and second portions of the void, thereby minimizing acoustic coupling between the receiver and the microphone.

Claims:
What is claimed is: 
     
       1. A mobile communication device comprising:
 a housing having an outer surface and internal sidewalls, wherein the outer surface and internal sidewalls define a void disposed at and below the outer surface of the housing; 
 a receiver disposed within the housing and below a first portion of the void, the receiver configured to emit sound into the void; 
 a microphone disposed within the housing and below a second portion of the void, the microphone configured to detect sound present in the void; and 
 an acoustic divider disposed within the void and laterally disposed between the receiver and the microphone, the acoustic divider acoustically isolating the first and second portions of the void. 
 
     
     
       2. The mobile communication device of  claim 1 , wherein the acoustic divider is in a shape of a triangular prism. 
     
     
       3. The mobile communication device of  claim 1 , wherein the acoustic divider comprises a sound-reflective material. 
     
     
       4. The mobile communication device of  claim 3 , wherein the acoustic divider comprises silicone. 
     
     
       5. The mobile communication device of  claim 1 , wherein the acoustic divider is a portion of the housing. 
     
     
       6. The mobile communication device of  claim 1 , wherein the acoustic divider is coupled to the housing. 
     
     
       7. The mobile communication device of  claim 6 , wherein the acoustic divider is coupled to the housing with an adhesive or a mechanical fastener. 
     
     
       8. The mobile communication device of  claim 1 , further comprising a mesh disposed near the outer surface of the housing, wherein the mesh encloses the void. 
     
     
       9. The mobile communication device of  claim 8 , wherein the mesh comprises a plurality of apertures configured to prevent debris from entering the void while permitting sound to exit and enter the void. 
     
     
       10. The mobile communication device of  claim 8 , wherein the acoustic divider has a peak that is disposed proximate to the mesh. 
     
     
       11. The mobile communication device of  claim 10 , wherein a height of the acoustic divider is substantially the same as a height of the void. 
     
     
       12. The mobile communication device of  claim 1 , wherein the housing comprises comprising an acoustic channel disposed between the receiver and the void, the acoustic channel configured to guide sound emitted by the receiver into the void. 
     
     
       13. The mobile communication device of  claim 12 , wherein the housing further comprises an acoustic sealing boot disposed around the acoustic channel. 
     
     
       14. The mobile communication device of  claim 13 , wherein the acoustic sealing boot comprises the acoustic divider. 
     
     
       15. A mobile communication device comprising:
 a housing having an outer surface and internal sidewalls, wherein the outer surface and internal sidewalls define a void disposed at and below the outer surface of the housing; 
 a receiver disposed within the housing and below a first portion of the void, the receiver configured to emit sound into the void; 
 a microphone disposed within the housing and below a second portion of the void, the microphone configured to detect sound present in the void; and 
 an acoustic divider comprising:
 a first sound channel configured to isolate sound emitted from the receiver; and 
 a second sound channel configured to isolate sound received by the microphone, wherein the first and second sound channels are acoustically isolated from one another. 
 
 
     
     
       16. The mobile communication device of  claim 15 , wherein heights of both first and second sound channels are equal to the height of the void. 
     
     
       17. A method of preventing acoustic coupling in a mobile communication device comprising:
 emitting, by a receiver, sound into a first portion of a void disposed in a housing of the mobile communication device; 
 reflecting, by an acoustic divider, the emitted sound, the reflecting causing the emitted sound to travel through the first portion and out of the void; and 
 detecting, by a microphone, at least a portion of the emitted sound, the detected sound traveling to the microphone from outside of the void through a second portion of the void, wherein the second portion of the void is acoustically isolated from the first portion of the void by the acoustic divider. 
 
     
     
       18. The method of  claim 17 , wherein the emitted sound is reflected away from the receiver by a slanted surface of the acoustic divider. 
     
     
       19. The method of  claim 17 , wherein the reflecting enables substantially all of the emitted sound in the first portion of the void to travel out of the void. 
     
     
       20. The method of  claim 17 , wherein the at least a portion of the emitted sound detected by the microphone comprises emitted sound reflected off of a user&#39;s ear.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/215,607, filed on Sep. 8, 2015, and titled “Mobile Device Acoustic Divider,” the disclosures of which are hereby incorporated by reference in their entirety for all purposes. 
    
    
     BACKGROUND 
     Modern mobile communication devices, such as smart phones and the like, utilize various forms of acoustic devices, such as receivers (i.e., speakers) and microphones. Receivers may emit sound into a user&#39;s ear when the device is being used, such as during a phone call. Microphones may be used to receive voice input from a user during a call, the voice input being transmitted to a communication device operated by the other user on the call. Microphones may also receive sound emitted from receivers and/or sounds emitted external to the device (e.g., background noise). In certain situations, the background noise may be too loud, thereby hindering a user&#39;s ability to clearly hear the sound emitted from the receiver. Additionally, contours of a user&#39;s ear may create variation in the strength of sounds emitted from the receiver, thus causing the emitted sounds to sound muffled when the device is placed in certain positions against the user&#39;s ear. 
     Modern mobile communication devices may incorporate active noise cancellation and auto loudness functionalities at the receiver to address such issues. To perform active noise cancellation, a microphone may be placed in a position to receive background noise. Once the background noise is received, the receiver may emit noise-canceling sounds that induce destructive interference to cancel out the background noise. An error-detecting microphone may be placed near a receiver to measure the strength of the noise-canceling sounds emitted from the receiver. Depending on the measured strength of noise-canceling sounds, the receiver may be driven to increase or decrease the strength of its outputted sound to achieve a target active noise cancellation. In addition to achieving a target active noise cancellation, the error-detecting microphone may also be used to equalize the sound emitted from the receiver. For example, if the receiver is placed against a user&#39;s ear such that the sound is muffled, the error-detecting microphone may detect the muffled sound and cause the device to emit a stronger sound from the receiver. 
     Implementation of an error-detecting microphone in modern mobile communication devices may prove problematic. For example, coupling may occur between the receiver and the error-detecting microphone that adversely affects execution of active noise cancellation and/or equalization. Thus, improvements to such functionalities are desired. 
     SUMMARY 
     Embodiments provide methods and apparatuses for improved sound detection by minimizing acoustic coupling. In certain embodiments, an acoustic divider may be incorporated into a mobile communication device to minimize coupling between a receiver and a microphone. The acoustic divider may improve the performance of particular functionalities (e.g., active noise cancellation and auto loudness equalization) of the mobile communication device. 
     In some embodiments, a mobile communication device includes a housing having an outer surface and internal sidewalls. The outer surface and internal sidewalls may define a void disposed at and below the outer surface of the housing. The mobile communication device may include a receiver and a microphone. The receiver may be disposed within the housing and below a first portion of the void, and may be configured to emit sound into the void. The microphone may be disposed within the housing and below a second portion of the void, and may be configured to detect sound present in the void. The mobile communication device may further include an acoustic divider that is disposed within the void and laterally disposed between the receiver and the microphone. The acoustic divider may acoustically isolate the first and second portions of the void. 
     In some embodiments, a method of preventing acoustic sound coupling in a mobile communication device includes emitting, by a receiver, sound into a first portion of a void disposed in a housing of the mobile communication device. The method includes reflecting, by an acoustic divider, the emitted sound. Reflection of the emitted sound may cause the emitted sound to travel through the first portion and out of the void. The method may further include detecting, by a microphone, at least a portion of the emitted sound. The detected sound may travel to the microphone from outside of the void and through a second portion of the void. The second portion of the void may be acoustically isolated form the first portion of the void by the acoustic divider. 
     A better understanding of the nature and advantages of embodiments of the present invention may be gained with reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified diagram of a mobile communication device interacting with a user, according to embodiments of the present invention. 
         FIG. 2A  is a simplified diagram of an internal portion of a mobile communication device without an acoustic divider, according to embodiments of the present invention. 
         FIG. 2B  is a simplified diagram of a top down perspective of a mobile communication device, according to embodiments of the present invention. 
         FIG. 3  is a simplified diagram of sound flow through an internal portion of a mobile communication device without an acoustic divider, according to embodiments of the present invention. 
         FIG. 4A  is a simplified diagram of an internal portion of a mobile communication device with an acoustic divider, according to embodiments of the present invention. 
         FIG. 4B  is a simplified diagram of a top down perspective of a void and an acoustic divider, according to embodiments of the present invention. 
         FIG. 4C  is a simplified diagram of sound flow through an internal portion of a mobile communication device with an acoustic divider, according to embodiments of the present invention. 
         FIGS. 5A-5D  are simplified diagrams of different types of acoustic dividers, according to embodiments of the present invention. 
         FIGS. 6A-6B  are simplified diagrams of anti-reflective layers for acoustic dividers, according to embodiments of the present invention. 
         FIG. 7  is a chart plot showing acoustic curves for different types of acoustic dividers, according to embodiments of the present invention. 
         FIG. 8  is a flow chart of a method of preventing acoustic coupling, according to embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments describe a mobile communication device having an acoustic divider for minimizing acoustic coupling between a receiver and a microphone. The acoustic divider may be positioned to prevent sound emitted from the receiver from being detected by the microphone before the sound exits the mobile communication device. For instance, the acoustic divider may reflect sound emitted from the receiver away from the microphone such that the sound may exit the device and reflect off a user&#39;s ear before the sound can be detected by the microphone. As will be discussed further herein, the acoustic divider may have various structures and be formed of various materials to minimize acoustic coupling between the receiver and the microphone. The structure of the acoustic divider may also be configured to be visually inconspicuous such that a user may not easily see the acoustic divider. Thus, the acoustic divider may not affect the appearance of the mobile communication device. 
     Minimal coupling between the receiver and the microphone may improve the noise-canceling and sound equalizing functionalities of a mobile communication device, thereby improving the mobile communication device&#39;s user experience. 
     To better understand the purpose of the acoustic divider, the role of the mobile communication device, as well as its structural configuration, is discussed in more detail herein. 
     I. Mobile Communication Device 
       FIG. 1  illustrates an exemplary mobile communication device  100  in accordance with some embodiments of the present invention. In embodiments, mobile communication device  100  may be a phone that is configured to transmit and receive sounds to and from a user  101 . Mobile communication device  100  may include a processor  102  coupled to a receiver  104  and microphones  106 ,  108 , and  110 . Receiver  104  may be any suitable electronic device component that emits sounds. For instance, receiver  104  may be a speaker that contains a diaphragm that vibrates at various frequencies to emit sound  114 . Emitted sound  114  may be heard by user  101 . 
     Microphones  106 ,  108 , and  110  may be electronic device components that are suitable for detecting sounds. Depending on where microphones  106 ,  108 , and  110  are located, different types of sounds may be detected. As an example, microphone  106  may be positioned near a bottom of mobile communication device  100  toward user  101 . Being positioned at the bottom of device  100  may allow microphone  106  to detect sounds spoken by user  101 . 
     In contrast to microphone  106 , microphone  108  may be disposed on a back of mobile communication device  100  to detect ambient/background noise  118  surrounding device  100 . Microphone  108  may be pointed away from user  101  and receiver  104  such that ambient/background noise  118  can be measured without detecting non-ambient/background sounds emitted by user  101  and receiver  104 . 
     Microphone  110  may be positioned near a top of mobile communication device  100  toward user  101 . In embodiments, microphone  110  may be positioned proximate to receiver  104  such that sounds emitted from receiver  104  may be detected by microphone  110 . Microphone  110  may be an error-detecting microphone that is used to detect sounds emitted from receiver  104 . Error-detecting microphones may be used to ensure that receiver  104  is emitting sound at a proper strength. 
     A. Active Noise Cancellation 
     In embodiments, processor  102  may be configured to perform various functionalities, such as active noise cancellation. Active noise cancellation is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the unwanted sound. Canceling a sound may be performed by creating destructive interference. Destructive interference is when two identical sound waves are phase shifted to a degree where the sound waves are inverted with respect to one another. For instance, two substantially identical sound waves may be phase shifted by 180 degrees to be inverted with respect to one another. The inverted sound waves cancel one another out because a positive amplitude value of one sound wave is offset by an equal-but-negative value of the other sound wave, thus effectively reducing the volume of the perceivable sound or substantially eliminating it altogether. 
     Complex algorithms that perform such active noise cancellation functionality may be carried out by processor  102  by interacting with and controlling various device components such as receiver  104  and microphones  108  and  110 . Microphone  108  may detect ambient noise  118  surrounding mobile communication device  100 . Detected ambient noise may be received by processor  102 , which may in turn cause receiver  104  to emit a noise-canceling sound  116  that causes destructive interference with detected ambient noise  118 . Accordingly, the volume of ambient noise  118  may be effectively reduced. 
     To ensure that detected ambient noise  118  is effectively reduced, microphone  110  may be utilized to measure effective sound  120 . In embodiments, effective sound  120  may include emitted noise-canceling sound  116  reflected off user&#39;s ear  112  which approximates the sound actually perceived by the user. Cancellation of ambient noise  118  may be achieved when the magnitude of noise-canceling sound  116  is substantially similar, if not the same, as the magnitude of ambient noise  118 . Thus, by detecting effective sound  120 , processor  102  may be able to determine the magnitude of noise-canceling sound  116  and ensure that noise-canceling sound  116  is emitted at the proper magnitude. If reflected sound  120  indicates that the magnitude of noise-canceling sound  116  is too small, processor  102  may cause receiver  104  to emit noise-canceling sound  116  at a larger magnitude. Alternatively, if processor  102  determines that the magnitude of noise-canceling sound is too large, it may cause receiver  104  to emit noise-canceling sound  116  at a smaller magnitude. 
     B. Auto Loudness 
     In addition to active noise cancellation, processor  102  may be configured to perform auto loudness. Auto loudness is a method of reducing sound variation across a variety of positions between mobile communication device  100  and user&#39;s ear  112 . A user&#39;s ear may have a variety of contour profiles. When mobile communication device  100  is pressed upon user&#39;s ear  112 , some areas of user&#39;s ear  112  may press against mobile communication device  100  and may cause sound emitted from receiver  104  to have a lower volume as perceived by the user. For instance, an ear&#39;s protruding contour may press against and/or block at least a portion of receiver  104 , causing effective sound  120  (i.e. the approximate sound heard by user&#39;s ear  112 ) to decrease in volume. A user&#39;s ear may also seal differently with mobile communication device  100  across a variety of positions. For example, if mobile communication device  100  is positioned such that a gap exists between it and user&#39;s ear  112 , there may be a poor seal created between the two, thereby decreasing the volume of the sound heard by user  101 . In embodiments, effective sound  120  may be detected by error-detecting microphone  110 . Processor  102  may determine that the volume of effective sound  120  is too low and thus compensate by increasing the volume of emitted sound  114 . Similarly, processor  102  may decrease the volume of emitted sound  114  when a contour profile of user&#39;s ear  112  causes an undesirable increase in volume of effective sound  120 . 
     Furthermore, auto loudness may also reduce sound variations across a variety of pressures between mobile communication device  100  and user&#39;s ear  112 . When mobile communication device  100  is pressed against user&#39;s ear  112 , the degree of applied pressure may cause a corresponding variation in sound volume. For instance, applying higher pressure may cause a greater area of mobile communication device  100  to press upon user&#39;s ear  112 . Thus, more regions of user&#39;s ear  112  may press upon receiver  104 , resulting in an increase in volume of effective sound  120 . As a result, processor  102  may determine that the emitted volume is too high and compensate for the higher volume by decreasing the volume of emitted sound  114 . Similarly, an increase in the volume of emitted sound  114  may occur for positions where a lower applied pressure causes a decrease in volume of effective sound  120 . 
     Both functionalities require proper detection of the volume of effective sound  120 . An inaccurate reading of effective sound  120  may result in an ineffective canceling of background noise, or an undesirable change in volume, thereby resulting in a poor user experience. In embodiments, the internal structure of mobile communication device  100  may enable accurate detection of emitted sound  120 , as will be discussed further herein. 
     II. Internal Structure 
       FIG. 2A  illustrates a cross-sectional view of an internal structure  200  of a mobile communication device, such as mobile communication device  201  shown in  FIG. 2B . The cross-sectional view of  FIG. 2A  may be taken across a portion of mobile communication device  201  where a receiver and a microphone are located to illustrate the internal structural configuration of the receiver and the microphone. One skilled in the art understands that the illustration of  FIG. 2A  illustrates only a portion of the internal structure of the mobile communication device, and that the mobile communication device may include several other structures and/or electrical components not depicted. 
     As shown in  FIG. 2A , internal structure  200  of the mobile communication device may include a housing  202  having an outer surface  204 . Housing  202  may include various internal structures (e.g., components that are inside the mobile communication device) that provide structural support for internal electrical components. Housing  202  may also include a frame within which the internal electrical components may be contained. In embodiments, housing  202 , which contains the various internal structures, may be formed of various materials. For instance, housing  202  may include an outer structure that is formed of glass. Additionally, internal support structures of housing  202  may be formed of rubber-like material, such as silicone. Furthermore, housing  202  may include a frame that is formed of a hard material, such as a metal (e.g., aluminum). In embodiments, housing  202  also includes internal sidewalls  203  and  205 . Internal sidewalls  203  and  205  may be substantially vertical sidewalls that define a vacant region within which sound may travel into and out of the mobile communication device. 
     In embodiments, a receiver  208  and a microphone  210  are disposed within housing  202 . Receiver  208  may be any suitable electrical component capable of emitting sound. For instance, receiver  208  may be a speaker having a diaphragm that can vibrate at various frequencies to emit sound waves. In certain embodiments, receiver  208  is a cross-sectional representation of receiver  104  illustrated in  FIG. 1 . Microphone  210  may be an electrical component configured to detect sound. For instance, microphone  210  may have a diaphragm that can vibrate according to a perceived sound to detect sound waves. Microphone  210  may be positioned proximate to and laterally from receiver  208  so that sound emitted from receiver  208  can be detected by microphone  210 . In embodiments, microphone  210  may be an error-detecting microphone, such as microphone  110  discussed herein with respect to  FIG. 1 . 
     According to some implementations, a void  206  is disposed in housing  202 . Void  206  may be defined by top surface  204  and internal sidewalls  203  and  205  of housing  202 . In embodiments, void  206  may be disposed above receiver  208  and microphone  210  and may extend downward from outer surface  204  of housing  202  toward receiver  208  and microphone  210 . Void  206  may be a vacant space within which sound may propagate from receiver  208 , and within which sound may enter into microphone  210 . As an example, sound  218  emitted from receiver  208  may enter into void  206 , and sound  220  from void  206  may be detected by microphone  210 . Accordingly, receiver  208  and microphone  210  may be acoustically coupled to void  206 . Void  206  may bridge between receiver  208  and microphone  210 . In some embodiments, sound  218  may include sounds  114  and  116  discussed herein with respect to  FIG. 1 . 
     Because receiver  208  as shown in  FIG. 2A  is disposed a distance away from void  206 , an acoustic channel  212  may be positioned between receiver  208  and void  206  to allow sounds  218  emitted from receiver  208  to enter into void  206  and exit the device. An acoustic sealing boot  214  may be positioned around acoustic channel  212  to acoustically seal acoustic channel  212  to the exterior of the mobile communication device. Because acoustic sealing boot  214  is a component disposed within the mobile communication device, acoustic sealing boot  214  may be part of housing  202  even though it is a physically separate structure. Additionally, acoustic sealing boot  214  may insulate other electrical components (e.g., microphone  210 ) from unintentional acoustic coupling. Unlike receiver  208 , microphone  210  may abut void  206 . Thus, sound entering into void  206  may be received by microphone  210  without having to use a separate acoustic channel. One skilled in the art understands that the embodiment illustrated in  FIG. 2A  is merely one embodiment that is not intended to be limiting. Receiver  208  and microphone  210  may be placed close to or far away from void  206  as long as it is acoustically coupled to void  206  without departing from the spirit and scope of the present invention. 
     In embodiments, a mesh  216  may be positioned to enclose void  206 . As an example, mesh  216  may be positioned proximate to a plane of outer surface  204  of housing  202 . Mesh  216  may be formed of a plurality of apertures configured to prevent debris from entering void  206  while permitting sound to propagate between void  206  and areas outside of the mobile communication device. Accordingly, mesh  216  may be have a grid-like pattern that forms a pattern of evenly distributed apertures through which sound may propagate. In embodiments, mesh  216  may cause certain sound waves to be trapped within void  206 . The trapped sound waves may cause acoustic coupling between receiver  208  and microphone  210 , as will be discussed further herein. 
     A. Mobile Communication Device without Acoustic Divider 
     As aforementioned herein, proper operation of functionalities such as active noise cancellation and auto loudness generally require accurate measurement of sounds emitted by receiver  208  that are heard by a user (e.g., accurate measurement of effective sound  120  discussed in  FIG. 1  herein). Conventional internal structures of mobile communication devices may be susceptible to inaccurate measurements of sounds heard by a user, as discussed herein with respect to  FIG. 3 . 
       FIG. 3  illustrates an exemplary flow of sounds for a conventional mobile communication device during use. Emitted sound  218  from receiver  208  may enter into void  206  and subsequently exit out of the mobile communication device through mesh  216 . Once exited from the mobile communication device, emitted sound  218  may be heard by a user, such as user  101  in  FIG. 1 . Portions  302  of emitted sound  218  outside of the mobile communication device may enter back into void  206  as effective sound  220  (e.g., by reflecting off the user&#39;s ear). Effective sound  220  may then be detected by microphone  210  for active noise cancellation and/or auto loudness functionalities. 
     As shown in  FIG. 3 , void  206  may bridge between receiver  208  and microphone  210 . Accordingly, void  206  may have a bridging portion  304  that is laterally disposed between receiver  208  and microphone  210 . Bridging portion  304  may allow a portion  306  of emitted sound  218  to flow across void  206  and be detected by microphone  210  before having a chance to exit out of the mobile communication device. Portion  306  of emitted sound  218  may be detected by microphone  210  in addition to the effective sound  220 . As a result, microphone  210  may not accurately detect effective sound  220 , as effective sound  220  may appear to have an additional sound from portion  306 . This disturbance detected by microphone  210  is known herein as “acoustic coupling.” 
     Acoustic coupling may occur because of the acoustic properties of mesh  216  as well as the bridging portion  304  of void  206 . For example, mesh  216  may reflect portion  306  of emitted sound  218  back into void  206 . Once reflected, portion  306  may propagate within void  206  through the bridging portion  304  and be subsequently detected by microphone  210 . Different frequencies may have a higher tendency to be reflected back into void  206 . As an example, lower frequencies may be more likely to be reflected back into void  206  and cause acoustic coupling. 
     According to embodiments of the present invention, an acoustic divider may be implemented within void  206  to minimize acoustic coupling between receiver  208  and microphone  210 , as will be discussed further herein. 
     B. Internal Structure with Acoustic Divider 
       FIG. 4A  illustrates an exemplary cross-section of a portion of a mobile communication device having an internal structure with an acoustic divider. For ease of discussion,  FIG. 4A  includes several components shared by the internal structure of  FIG. 3 . Components that are shared between both figures have identical reference numbers for ease of reference. 
     As shown in  FIG. 4A , an acoustic divider  402  may be implemented within void  206 . In some embodiments, acoustic divider  402  may be disposed within bridging portion  304  of void  206 . Acoustic divider  402  may be positioned in void  206  such that void  206  is divided into two portions: a receiver portion  404  (i.e. a first portion) and a microphone portion  406  (i.e. a second portion). In embodiments, receiver portion  404  may be acoustically coupled with receiver  208  such that sounds emitted from receiver  208  may be emitted into receiver portion  404  of void  206 . Additionally, microphone portion  406  may be acoustically coupled with microphone  210  such that sounds entering into microphone portion  406  from outside the mobile communication device may be detected by microphone  210 . Thus, acoustic divider  402  may be positioned laterally between receiver  208  and microphone  210 . 
     1. Structure of Acoustic Dividers 
     In embodiments, the structural dimensions of acoustic divider  402  may affect the degree of coupling between receiver portion  404  and microphone portion  406 . Taller acoustic dividers  402  may result in better mitigation of acoustic coupling between receiver  208  and microphone  210 . For instance, acoustic divider  402  may have a height  408  that is substantially similar to, if not the same as, a height  410  of void  206 . Having the same height ensures that emitted sound from receiver  208  in receiver portion  404  does not flow over acoustic divider  402  into microphone portion  406  and be subsequently detected by microphone  210 . In such instances, a top peak  414  of acoustic divider  402  may be located against mesh  216  or very close to it. In some embodiments, height  408  of acoustic divider  402  ranges between 0.5 to 3 mm. In certain embodiments, height  408  is approximately 1 mm. 
     In addition to the height, a width of acoustic divider  402  may also affect the amount of acoustic coupling. Larger widths may result in better acoustic isolation, thereby resulting in less acoustic coupling. In embodiments, acoustic divider  402  may have a width  412 . Width  412  may also be wide enough to structurally support acoustic divider  402 . For instance, width  412  may be wide enough to substantially minimize acoustic coupling. In addition to mitigating acoustic coupling, width  412  may also be wide enough to ensure that acoustic divider  402  does not break when exposed to typical forces or when exposed to extreme forces, such as when the mobile communication device is dropped. Furthermore, width  412  may also be wide enough to withstand handling during assembly. In embodiments, width  412  may range between 0.5 to 3 mm, with some particular embodiments ranging between 0.5 to 1 mm. 
     In embodiments, acoustic divider  402  may be configured in various ways. For instance, acoustic divider  402  may be formed as part of housing  202 . Specifically, acoustic divider  402  may be a portion of acoustic sealing boot  214  of housing  202 . Acoustic sealing boot  214  may be a separate part of housing  202 . In such configurations, acoustic divider  402  and acoustic sealing boot  214  may from a single unitary body. In other embodiments, acoustic divider  402  may be a separate structure that is fixed in position. As an example, acoustic divider  402  may be a separate structure that is attached to acoustic sealing boot  214  with an adhesive or a mechanical fastener. As another example, acoustic divider  402  may be a separate structure that is attached to mesh  216 . It is to be appreciated that acoustic divider  402  may be attached to any structure capable of mechanically supporting acoustic divider  402 . 
     In embodiments, acoustic divider  402  may have a cross-sectional shape of a triangle as shown in  FIG. 4A . Having sloped side surfaces may cause sound to change direction when it reflects off acoustic divider  402 . Additionally, sloped side surfaces minimizes visual impact when observed from above (e.g., through mesh  216 ). Top peak  414  of acoustic divider  402  may have a small footprint such that a user may not easily see the presence of acoustic divider  402 . Accordingly, an aesthetic appeal of the mobile communication device may not be impacted by the presence of acoustic divider  402 . 
       FIG. 4A  is a two-dimensional illustration of the internal structure of a portion of the mobile communication device. One skilled in the art understands that there is a depth component to  FIG. 4A  that is not readily apparent. To show this depth,  FIG. 4B  illustrates a top view perspective of void  206  and acoustic divider  402 . As shown, acoustic divider  402 , although illustrated as a triangle in  FIG. 4A , may be a triangular prism that spans across a vertical component of void  206 . 
     In embodiments, acoustic divider  402  may be formed of any suitable material capable of preventing the propagation of sound. For instance, acoustic divider  402  may be formed of a sound-reflective material. In some embodiments, acoustic divider  402  may be formed of silicone, plastic, foam, steel, aluminum, or the like. 
       FIG. 4C  illustrates the flow of sound for a mobile communication device having an acoustic divider  402 . As shown, emitted sound  218  may emit from receiver  208 , flow into receiver portion  404  of void  206  and out of the mobile communication device. Portions  302  of emitted sound  218  may flow into microphone portion  406  of void  206  and be detected by microphone  210 . Portions  302  can be reflected by a user&#39;s ear, for example, into microphone portion  406  of void  206 . Unlike the flow of sounds in instances where there is no acoustic divider  402 , portion  306  of emitted sound  218  that is emitted into receiver portion  404  of void  206  may be prevented from propagating into microphone portion  406  by acoustic divider  402 . In some embodiments, portion  306  of emitted sound  218  is reflected by acoustic divider  402 . Once reflected, portion  306  of emitted sound  218  may exit out of the mobile communication device. Portions  302  and  306  of sound  218  may then enter back into void  206  as effective sound  220 . Effective sound  220  may then be detected by microphone  210 . In embodiments, microphone  210  may thus only detect sound entering into void  206  from outside of the mobile communication device, such as effective sound  220 . Accordingly, acoustic divider  402  may substantially minimize acoustic coupling. 
       FIGS. 4A and 4C  illustrate acoustic divider  402  as a triangular prism; however, embodiments are not so limited. For instance, acoustic divider  402  may have other geometrical shapes and materials such that acoustic coupling between a receiver and a microphone is minimized, without departing from the spirit and scope of the present invention. 
     2. Types of Acoustic Dividers 
       FIGS. 5A-5D  illustrate cross-sectional perspectives of different types of acoustic dividers according to embodiments of the present invention. As illustrated,  FIGS. 5A-5D  are each close-up images of the region in  FIG. 4C  bounded by dotted lines Each type of acoustic divider may have a specific geometric shape and/or be formed of a particular material. 
       FIG. 5A  illustrates an acoustic divider  502  that is in the shape of a rectangular prism. As shown in  FIG. 5A , acoustic divider  502  appears as a rectangle, but the depth component of the image is not readily apparent. Acoustic divider  502  may have substantially straight sidewalls such that acoustic divider  502  has equal width across its height. That is, acoustic divider  502  may have a non-tapering structure that is just as wide at its top as at its base. Having a non-tapering structure may allow acoustic divider  502  to achieve maximum reduction of acoustic coupling across its entire height. Acoustic divider  502  may be formed of a material that reflects sound, such as silicone. 
     Although acoustic divider  502  has vertical sidewalls, embodiments are not limited to such configurations. For instance, acoustic divider  502  may have curved sidewalls, such as concave or convex sidewalls, for isolating acoustic sounds. Further, in some alternative embodiments, acoustic divider  502  may incorporate a tapered structure. 
     In embodiments, the rectangular structure of acoustic divider  502  may cause acoustic divider  502  to have a large visual footprint. Given its large visual footprint, a user may be able to see acoustic divider  502  from outside of the mobile communication device. 
     One way to minimize the visual impact of acoustic divider  502  is to decrease its height so that its top surface  503  is farther away from top of the void  206 .  FIG. 5B  illustrates an acoustic divider  504  that is in the shape of a rectangular prism that has a smaller height than acoustic divider  502 . In embodiments, acoustic divider  504  may not minimize acoustic coupling as well as acoustic divider  502  of  FIG. 5A , but its visual impact may be slightly decreased. As shown in  FIGS. 5A and 5B , the structure of an acoustic divider can be altered to achieve better resistance to acoustic coupling or to reduce its visual footprint. 
       FIG. 5C  illustrates an acoustic divider  506  in the shape of a rectangular prism, such as acoustic divider  502 , but formed of a different material. In embodiments, acoustic divider  506  may be formed of foam. Foam is a porous material that has sound-absorbing properties. Thus, acoustic divider  506  may absorb sound to prevent acoustic coupling. Similar to acoustic dividers  502  and  504 , the size of acoustic divider  506  can be adjusted to reduce visual footprint or to enhance the alleviation of acoustic coupling. 
       FIG. 5D  illustrates another structure that may be used to prevent acoustic coupling. As shown, two separate sound channels may be used to prevent acoustic coupling. For example, a receiver sound channel  508  and a microphone sound channel  510  may be used to prevent acoustic coupling. In embodiments, receiver sound channel  508  may contain sound emitted from a receiver to stay within receiver sound channel  508 . Likewise, microphone sound channel  510  may prevent detection of sound emitted from the receiver before the sound exits the mobile communication device. Thus, the receiver sound channel  508  and the microphone sound channel  510  may be acoustically isolated from one another. By creating this acoustic isolation, acoustic coupling may be minimized. Heights of both the receiver sound channel  508  and the microphone sound channel  510  may be sufficient to extend across the entire height of void  206 . For instance, the heights of both sound channels  508  and  510  may be equal to the height of void  206 . In such instances, top surfaces of channels  508  and  510  may be adjacent to, or even directly contacting, mesh  216  to substantially minimize coupling of sound within void  206 . In embodiments, sound channels  508  and  510  may be formed of any suitable material such as a plastic or a metal. In certain embodiments, sound channels  508  and  510  are formed of aluminum. It is to be appreciated that sound channels  508  and  510  may be a part of the housing, such as housing  202  in  FIG. 2A . 
     C. Utilizing Layers to Minimize Visual Footprint 
     Visibility of an acoustic divider outside the mobile communications device may adversely affect the overall visual aesthetics of the device. To minimize such visual footprint, a layer may be formed on top of the acoustic divider. The layer may have certain attributes that minimize reflection of light back to a user, thereby making the acoustic divider harder to see. 
       FIG. 6A  illustrates an exemplary acoustic divider  602  having an anti-reflective layer  604 . Acoustic divider  602  may have a top surface  612  and side surfaces  606  and  608 . In embodiments, anti-reflective layer  604  may be disposed on top surface  612 . Anti-reflective layer  604  may be a layer of material that minimizes reflection of light. For instance, anti-reflective layer  604  may be a layer of dark colored material. The dark colored material may absorb a broad spectrum of visual light. In some embodiments, anti-reflective layer  604  (e.g., a dark colored material) may have a rough surface. The rough surface may be formed of a random arrangement of small surface variations. The arrangement of small surface variations may enhance the anti-reflective properties of layer  604  by scattering light incident on layer  604 . In other embodiments, anti-reflective layer  604  may have an organized arrangement of surface variations, as shown in  FIG. 6B  discussed herein. 
       FIG. 6B  illustrates acoustic divider  602  having an alternative anti-reflective layer  610  comprising an organized arrangement of surface variations. For instance, anti-reflective layer  610  may be a surface that is triangulated. A triangulated surface may have an organized arrangement of sloped surfaces that reflect incident light away from its source. By reflecting light away from its source, anti-reflective layer  610  may make it more difficult for a user to see acoustic divider  602  from outside the mobile communications device. 
     Although  FIGS. 6A and 6B  illustrate anti-reflective layers on a top surface  612  of acoustic divider  602 , embodiments are not limited to such configurations. For example, anti-reflective layers  604  and  610  may be disposed on side surfaces  606  and  608  to prevent side surfaces  606  and  608  from increasing the visual footprint of acoustic divider  602 . Furthermore, one skilled in the art understands that even though  FIGS. 6A and 6B  illustrate acoustic divider  602  as a rectangular prism, such embodiments are not intended to be limiting. For instance, acoustic divider  602  may be in the shape of a triangular prism that has anti-reflective layers on its slanted side surfaces. In such embodiments, an anti-reflective layer may not be disposed on a top surface of the acoustic divider because of its top peak. 
     1. Effectiveness of Acoustic Dividers 
     As discussed herein, the geometry of the acoustic divider according to embodiments of the present invention may determine its ability to prevent acoustic coupling. Some geometries may perform better at preventing acoustic coupling than other geometries.  FIG. 7  illustrates a chart plot  700  to better illustrate the different acoustic coupling performances of the different geometries. It is to be appreciated that the presence of the acoustic divider also decreases variation in the detected sound. That is, sounds detected by a microphone when an acoustic divider is present can be more consistent across a number of samples than without the acoustic divider. Such variation is not illustrated in  FIG. 7 , but one skilled in the art understands that implementing the acoustic divider decreases sound variation. 
     Chart plot  700  has an X-axis representing frequencies of sounds in logarithmic scale, and a Y-axis representing volume in decibels (dB) increasing upwards in increments of 20 dB. The curves plotted on chart plot  700  represent emitted sound (i.e., emitted sound  114  in  FIG. 1 ) from a receiver (i.e., receiver  104  in  FIG. 1  or receiver  208  in  FIGS. 3 and 4A-4B ) as detected by an error-detecting microphone (i.e., microphone  110  in  FIG. 1  or microphone  210  in  FIGS. 3 and 4A-4B ). 
     Three curves are plotted on chart plot  700 : an ideal curve  702 , a rectangular acoustic divider curve  704 , and a triangular prism acoustic divider curve  706 . As shown in  FIG. 7 , ideal curve  702  is illustrated as a solid line, rectangular divider curve  704  is a dashed line, and triangular divider curve  704  is a dotted line. Ideal curve  702  may represent sound detected by the error-detecting microphone when no acoustic coupling is present. Thus, ideal curve  702  may be compared with other curves to show how effectively the different dividers can minimize acoustic coupling. 
     As illustrated in  FIG. 7 , rectangular prism divider curve  704  and triangular prism divider curve  706  may not significantly depart from ideal curve  702 . In embodiments, a low frequency boost in detected sound may be received by the error-detecting microphone. For example, sounds detected in a low frequency region  708  of divider curves  704  and  706  may depart from ideal curve  702 . This light deviation from ideal curve  702  may be caused by minimal acoustic coupling between the receiver and the microphone. When no acoustic divider is implemented, a greater deviation from ideal curve  702  within low frequency region  708  may be observed. 
     Rectangular prism divider curve  704  may have less departure than triangular prism divider curve  706  because, as aforementioned herein, the non-tapering structural configuration of a rectangular prism acoustic divider more effectively decreases acoustic coupling between the receiver and the microphone. Although a triangular prism acoustic divider has a slightly higher deviation than a rectangular prism acoustic divider, its magnitude of deviation is still lower than implementations without an acoustic divider. The lower deviation in the received sound results in more accurate calculations for the complex algorithms carrying out the noise-cancellation functionalities, thereby resulting in better performance of noise cancellation. Furthermore, the lower deviation seen in noise-cancellation functionality also applies to lower deviation in auto loudness functionalities. Thus, complex algorithms performing auto loudness may also see improved accuracy in its calculations. 
     III. Method of Preventing Acoustic Coupling 
       FIG. 8  illustrates a method  800  of preventing acoustic coupling in a mobile communication device according to embodiments of the present invention. At block  802 , sound may be emitted into a first portion of a void. For instance, sound  218  from  FIG. 4C , which may include sound  114  and  116  in  FIG. 1 , may be emitted from a receiver, such as receiver  208  in  FIG. 4C . The emitted sound may enter into the receiver portion of the void, e.g., receiver portion  404  of void  206  in  FIG. 4C . 
     At block  804 , the emitted sound may be reflected by an acoustic divider, such as acoustic divider  402  in  FIG. 4C . The emitted sound may be portion  306  of sound  218  emitted from receiver  208  as discussed in  FIG. 4C . In some embodiments, the acoustic divider may be in the shape of a triangular prism. Once reflected by the acoustic divider, the emitted sound may reflect back into and/or out of the first portion of the void. In some instances, sound reflected off of the acoustic divider may exit out of the mobile communication device such that it may be heard by a user. 
     At block  806 , at least a portion of the emitted sound may be detected by a microphone, such as microphone  210  in  FIG. 4C . In embodiments, the portion of emitted sound may be portion  216  of emitted sound  218  as discussed in  FIG. 4C . Portion  216  of emitted sound may enter into a second portion of the void as effective sound  220 , which may be sound that represents what is heard by a user. In embodiments, the second portion of the void may be microphone portion  406  of void  206 . Microphone  210  may detect effective sound  220  and may not detect portions of emitted sound  218  before emitted sound  218  exited the mobile communication device. Accordingly, acoustic coupling may be mitigated. In certain embodiments, the second portion of the void (e.g., microphone portion  406  of void  206  in FIG.  4 C) may be acoustically isolated from the first portion of the void (e.g., receiver portion  404  of void  206  in  FIG. 4C ). 
     The above description illustrates various embodiments of the present invention along with examples of how aspects of the present invention may be implemented. The above examples and embodiments should not be deemed to be the only embodiments, and are presented to illustrate the flexibility and advantages of the present invention as defined by the following claims. For example, although certain embodiments have been described with respect to particular process flows and steps, it should be apparent to those skilled in the art that the scope of the present invention is not strictly limited to the described flows and steps. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added, or omitted. As another example, although certain embodiments have been described using a particular combination of hardware and software, it should be recognized that other combinations of hardware and software are possible, and that specific operations described as being implemented in software can also be implemented in hardware and vice versa. 
     The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense. Other arrangements, embodiments, implementations and equivalents will be evident to those skilled in the art and may be employed without departing from the spirit and scope of the invention as set forth in the following claims.

Metadata:
Filing Date: 20151218
Publication Date: 20170912
Grant Date: 20170912
Priority Date: 20150908
Inventors: Wah Melissa A.
Hristov Stoyan P.
TAMCHINA PHILLIP
Assignee: APPLE INC
CPC Classifications: [{"code": "G10K2210/3219", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2430/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/3226", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K11/1788", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G10K2210/3224", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/1081", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R29/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/34", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "G10K11/17881", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/035", "inventive": true, "first": false, "tree": "[]"}, {"code": "G10K11/17857", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2410/05", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/086", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R3/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "G10K2210/3226", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/3224", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/3219", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/1081", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K11/17881", "inventive": true, "first": true, "tree": "[]"}, {"code": "G10K11/17857", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2410/05", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R3/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/086", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/035", "inventive": true, "first": false, "tree": "[]"}, {"code": "G10K2210/3226", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/3224", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/3219", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K2210/1081", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2430/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R29/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2430/01", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 58189780