PATENT DOCUMENT

Publication Number: US-9573165-B2
Application Number: US-201414474435-A
Country: US
Kind Code: B2

Title: Hydrophobic mesh cover

Abstract:
A screen having a hydrophobic portion to resist the entry of liquid into an acoustic module and a hydrophilic portion to aid in the removal of liquid from an acoustic chamber is described. The screen is placed in an orifice in the acoustic module between the external environment and the internal acoustic chamber.

Claims:
We claim: 
     
       1. An acoustic module, comprising:
 an acoustic chamber; 
 an audio component disposed within the acoustic chamber; 
 a port adjacent an external environment and the acoustic chamber; and 
 a semi-permeable barrier material disposed within the port and comprising:
 a first side facing the external environment and exhibiting a hydrophobic characteristic; 
 a second side facing the acoustic chamber and opposite the first side, and exhibiting a hydrophilic characteristic; wherein the audio component is configured to emit inaudible acoustic waves that move moisture toward and through the semi-permeable barrier material. 
 
 
     
     
       2. The acoustic module of  claim 1 , wherein the semi-permeable barrier material is a synthetic mesh. 
     
     
       3. The acoustic module of  claim 1 , wherein the first side includes a hydrophobic coating selected from among manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon-nanotubes, silica nano-coating, polytetrafluoroethylene, silicon, and various flouropolymers. 
     
     
       4. The acoustic module of  claim 1  wherein the second side includes a hydrophilic coating selected from silicon dioxide (SiO 2 ), polyethylene glycol and silicon nitride (SiN 1 ). 
     
     
       5. The acoustic module of  claim 2 , wherein the first side includes a first mesh portion having a smaller opening size than the second side. 
     
     
       6. The acoustic module of  claim 5 , wherein the second side includes a second mesh portion having a larger opening size than the first side. 
     
     
       7. The acoustic module of  claim 6 , wherein the first mesh portion is laminated onto the second mesh portion. 
     
     
       8. A cover for an acoustic module that includes an audio component, the cover comprising:
 a liquid permeable material having a first side and a second side; 
 the first side including a hydrophobic coating; and 
 the second side including a hydrophilic coating configured to be oriented towards the audio component, 
 wherein the liquid permeable material allows liquid to pass from the first side of the liquid permeable material to the second side of the liquid permeable material to dry the acoustic module. 
 
     
     
       9. The cover of  claim 8  wherein the liquid permeable material comprises synthetic mesh. 
     
     
       10. The cover of  claim 8  wherein the hydrophilic coating includes a coating selected from silicon dioxide (SiO 2 ), polyethylene glycol and silicon nitride (SiN 1 ). 
     
     
       11. The cover of  claim 8 , wherein the hydrophobic coating is selected from among:
 manganese oxide polystyrene; 
 zinc oxide polystyrene; 
 precipitated calcium carbonate; 
 carbon-nanotubes; 
 silica nano-coating; 
 polytetrafluoroethylene; 
 silicon; and 
 a flouropolymer. 
 
     
     
       12. A cover for an acoustic module comprising:
 a hydrophilic mesh material having a first size mesh opening; and 
 a hydrophobic mesh material having a second size mesh opening smaller than the first size mesh opening; wherein the hydrophilic mesh material is adjacent to the hydrophobic mesh material to form the cover, 
 wherein when liquid is received at the hydrophilic mesh material, the hydrophilic and hydrophobic mesh materials cooperate to dry the acoustic module by moving the liquid through the cover. 
 
     
     
       13. The cover of  claim 12 , wherein the hydrophilic and hydrophobic mesh materials are synthetic meshes. 
     
     
       14. The cover of  claim 12 , wherein the hydrophobic mesh material includes a hydrophobic coating selected from among: manganese oxide polystyrene; zinc oxide polystyrene; precipitated calcium carbonate; carbon-nanotubes; silica nano-coating; polytetrafluoroethylene; silicon; and a flouropolymer. 
     
     
       15. The cover of  claim 12  wherein the hydrophilic and hydrophobic mesh materials are offset from one another. 
     
     
       16. A device for drying an acoustic chamber, the device comprising:
 a cover material covering a port of the acoustic chamber, the cover material comprising a screen having a hydrophobic side and a hydrophilic side, wherein: 
 the hydrophobic side is adjacent an exterior environment outside the acoustic chamber; 
 the hydrophilic side is adjacent an interior portion of the acoustic chamber; and 
 the screen is configured to move liquid within the acoustic chamber from the hydrophilic side to the hydrophobic side by capillary action. 
 
     
     
       17. The device of  claim 16  wherein:
 the hydrophobic side includes a first mesh portion having a first opening size; 
 the hydrophilic side includes a second mesh portion having a second opening size larger than the first opening size; and 
 the first mesh portion is laminated to the second mesh portion. 
 
     
     
       18. The device of  claim 16  further comprising a sensor to detect the presence of liquid in the acoustic chamber. 
     
     
       19. The device of  claim 18  wherein the sensor is selected from among: an acoustic sensor; a pressure sensor; an optical sensor; a moisture sensor;
 and a conductive sensor. 
 
     
     
       20. The device of  claim 16  wherein the acoustic chamber includes at least one of a speaker or a microphone.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a nonprovisional patent application of and claims the benefit to U.S. Provisional Patent Application No. 62/040,618, filed Aug. 22, 2014 and titled “Hydrophobic Mesh Cover,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to acoustic modules, and more specifically to prevention of liquid from entering an acoustic cavity of an acoustic module and facilitating removal of any liquid that does so enter. In still greater particularity, the disclosure relates to a mesh screen with two surfaces, one to inhibit entry of liquid into the acoustic module and another layer to facilitate the removal of any liquid that does pass through the first layer and enters into the acoustic module. 
     BACKGROUND 
     An acoustic module integrated into a device can be used to transmit or receive acoustic signals. In a typical device, the acoustic signals are transmitted to or received from a surrounding medium (e.g., air). To facilitate communication with the surrounding medium, the acoustic module may be at least partially exposed to the environment surrounding the device via one or more orifices or openings that permit sound waves to both enter and exit the acoustic module. 
     In some cases, an acoustic module may include one or more components that are disposed within a cavity or chamber to help protect the components from the external environment. In some cases, the components may be acoustically coupled to the cavity to produce a particular acoustic response. Typically, at least some portion of the cavity or chamber is exposed to the external environment to allow acoustic signals to be transmitted to or received from the surrounding medium. However, because the cavity or chamber is exposed to the external environment, liquid or moisture may accumulate or become trapped in the cavity or chamber, which may impair the performance of the acoustic module. 
     Thus, it is generally desirable to prevent the ingress of moisture into an acoustic module. However, in some cases, the complete prevention of liquid ingress is not possible or practical. Thus, there may be a need for a system and technique for facilitating the evacuation or removal of moisture that has entered or accumulated in an acoustic module. It would be particularly useful to have a device that acts to both inhibit entry of liquid into the acoustic module and to facilitate the removal of any liquid that does pass through the device and enters into the acoustic module chamber. 
     SUMMARY 
     The embodiments described herein are directed to an acoustic module that includes a screen cover portion which is configured to both inhibit entry of liquid into the acoustic module chamber and to facilitate the removal of any liquid that does enter into the acoustic module chamber. In one example embodiment, the acoustic module includes a mesh cover that is configured to be hydrophobic on an external surface, thereby repelling liquid from outside the acoustic module, and hydrophilic on an interior surface,e thereby facilitating the removal of liquid that has entered the acoustic module chamber. In some embodiments, the acoustic module is incorporated into a portable electronic device. 
     In one embodiment, the acoustic module includes a two layer mesh screen to cover the opening of the acoustic module associated with the exterior of the portable electronic device. In some embodiments, the acoustic module chamber is a speaker element. In some other embodiments, the acoustic element is a microphone element. In one example embodiment, the speaker element or the microphone element is configured to generate an acoustic pulse that facilitates movement of the liquid within the acoustic module chamber in combination with the mesh cover. 
     The present disclosure includes systems, techniques, and apparatuses for inhibiting the entry of liquid into, and expelling liquid from, a cavity of an acoustic module through an orifice or opening of the module. In one example, the hydrophobicity of the screen which covers the entry port into the acoustic chamber from outside the portable electronic device is varied to inhibit moisture into, and facilitate the removal of moisture from, the acoustic module. Additionally, the acoustic module, which may include a speaker mechanism, may be configured to produce acoustic waves that also facilitate expulsion of liquid from the acoustic module. 
     Additionally, in some cases, an acoustic sensor (e.g., a microphone) may be used to detect the presence of liquid or quantify the amount of liquid in the acoustic cavity. For example, an acoustic module may generate a calibrated tone or stimulus that results in an acoustic signal that is received by the acoustic sensor. The presence of liquid and/or the amount of liquid may be determined based on the acoustic signal received by the acoustic sensor. In some cases, additional liquid expulsion operations may be performed in response to this determination. 
     One sample embodiment may take the form of a semi-permeable barrier material for an acoustic module, said module including a port adjacent an external environment and an acoustic chamber, the material comprising: a first side facing said external environment and exhibiting a hydrophobic characteristic; and a second side facing said acoustic chamber and opposite the first side, and exhibiting a hydrophilic characteristic; wherein the material is positioned within the port. 
     Another sample embodiment takes the form of a method for manufacturing a cover for an acoustic module, comprising the operations of: providing a first mesh material having a first size mesh opening; providing a second mesh material having a second size mesh opening smaller than said first size mesh opening; and laminating said first mesh material and said second mesh material to form said cover. 
     Still another embodiment may take the form of a method for removing liquid from an acoustic chamber comprising the operations of: placing a screen portion having a hydrophobic side and a hydrophilic side in a port of said acoustic chamber; positioning said hydrophobic side adjacent the an exterior environment outside said acoustic chamber; positioning said hydrophilic side adjacent an interior portion of said acoustic chamber; detecting the presence of liquid in said interior portion; and inducing said liquid to move to said hydrophilic side; whereby said liquid moves from said hydrophilic side to said hydrophobic side by capillary action. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts an electronic device having at least one acoustic module; 
         FIG. 2  depicts a block diagram of example functional components of an electronic device having at least one acoustic module. 
         FIG. 3  depicts a cross-sectional view of an example acoustic module taken along section A-A of  FIG. 1 ; 
         FIG. 4  depicts a cross-sectional view of one embodiment of an acoustic module taken along section A-A of  FIG. 1 ; 
         FIG. 5  depicts a perspective view of a two layer mesh screen; 
         FIG. 6  depicts a mesh screen coated in accordance with one embodiment; 
         FIG. 7  is a flow chart depicting a process for removing liquid from an acoustic chamber; 
         FIG. 8  is a flow chart of one method for manufacturing a cover for an acoustic chamber; and 
         FIG. 9  is a flow chart of an alternate method for manufacturing a cover for an acoustic chamber. 
     
    
    
     DETAILED DESCRIPTION 
     The description that follows includes embodiments of systems and processes that embody various elements of the present disclosure. Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings and in particular with reference to  FIGS. 1-9 . It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. Those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting as the described disclosure may be practiced in a variety of forms in addition to those described herein. Like reference numerals denote like structure throughout each of the various figures. 
       FIG. 1  depicts an example portable electronic device  11  including an acoustic module  12  contained within portable electronic device  11 . In this example, portable electronic device  11  is a mobile telephone, such as a smart phone, although alternative embodiments may take the form of any suitable electronic device including (but not limited to) a tablet computing device, a portable computer, a media player, a wearable computing device, a device for telling time, a health-monitoring device, and so on. Certain embodiments may include a display for depicting information to a user; the display  13  may be touch-sensitive in some embodiments and function to accept user input. In the example embodiment shown in  FIG. 1 , portable electronic device  11  also includes interface buttons  14  for providing additional input to portable electronic device  11 . Portable electronic device  11  includes a housing  15  used to protect the internal components of portable electronic device  11 . Housing  15  may be formed from a substantially rigid shell structure that serves as the mechanical support for various components of portable electronic device  11 , including touch screen display  13 , interface buttons  14 , and one or more acoustic modules  12 . 
     As shown in  FIG. 1 , housing  15  includes a first acoustic speaker port  16  that is coupled to acoustic module  12 . In this example, acoustic module  12  is configured to function as an earpiece or speaker for mobile telephone  11 . Housing  15  also includes a microphone port  17  extending through the housing  15 , coupled to a microphone acoustic module  18 . It should be appreciated that the speaker port  16  and/or microphone port  17  may be located on any suitable surface of the electronic device and need not occupy a particular area. 
     Acoustic modules  12  and  18  are coupled to respective acoustic ports  16  and  17 . Acoustic modules  12  and  18  are configured to transmit and/or receive signals in response to a command or control signal provided by a controller  19  as described in  FIG. 2  below. In some cases, intermediate circuitry may facilitate the electrical interface between the controller  19  and the acoustic modules  12  and  18 . 
       FIG. 2  depicts a schematic diagram of example components of portable electronic device  11  that are located within the housing  15 , although many components are omitted for purposes of simplicity and clarity. As shown in  FIG. 2 , portable electronic device  11  may include one or more controller units  19 , one or more speaker acoustic modules  12 , and/or one or more microphone acoustic modules  18 . In this example, the controller device  19  may execute instructions and carry out operations associated with portable electronic devices as are described herein. Using instructions from device memory, controller  19  may regulate the reception and manipulation of input and output data between components of the electronic device  11 . Controller  19  may be implemented in a computer chip or chips. Various architectures can be used for controller  19  such as microprocessors, application specific integrated circuits (ASICs) and so forth. Controller  19 , together with an operating system, may execute computer code and manipulate data. The operating system may be a well-known system such as iOS, Windows, Unix or a special purpose operating system or other systems as are known in the art. Controller device  19  may include memory capability to store the operating system and data. Controller device  19  may also include application software to implement various functions associated with the portable electronic device. Portable electronic device  11  also may include a wireless transceiver  21  connected to controller  19 . 
     Although  FIG. 2  illustrates the portable electronic device  11  as including particular components, this is provided only as an example. In various implementations, the portable electronic device  11  may include additional components beyond those shown and/or may not include some components shown without departing from the scope of the present disclosure. For example, portable electronic device  11  may include only one of a speaker acoustic module  12  and a microphone acoustic module  18 . Alternatively, the device may include additional acoustic modules or other types of acoustic modules. 
     In the embodiment example described herein, the portable electronic device  11  is a smart phone. However, it is understood that portable electronic device  11  depicted in  FIG. 1  is simply one example and that other types of devices may include one or more acoustic modules. Other types of devices include, without limitation, a laptop computer, a desktop computer, a cellular phone, a media player, a wearable device, a health-monitoring device, a tablet computer, a mobile computer, a telephone, and/or other electronic device. 
     An example acoustic module is shown in  FIG. 3 , depicting a cross-sectional view of speaker acoustic module  12  and speaker acoustic port  16  taken along section A-A of  FIG. 1 . The cross-sectional view of  FIG. 3  is not drawn to scale and may omit some elements for clarity. Further, the cross-sectional view may show a sample spatial relationship between various components that may vary between embodiments, and so is meant as an example only. 
     Speaker acoustic port  16  includes an opening  22  that facilitates the transmission of audible signals from acoustic module  12  to an exterior environment, such as the user&#39;s ear. Orifice  22  extends through the housing  15  and connects internal components of the acoustic module  12  with the external environment. In other examples, a single acoustic port may include or be formed from multiple orifices. As described in more detail with respect to  FIG. 4 , speaker acoustic port  16  may also include a cover  24 , which may include a semi-permeable barrier such as screen mesh or other protective element configured to inhibit ingress of liquid or other foreign matter but allowing sound waves to pass therethrough. In an alternate embodiment, housing  15  also includes a second acoustic port  17  that is coupled to a microphone acoustic module  18  that is configured to function as a mouthpiece or microphone for the mobile telephone. Microphone acoustic port  17  also includes one or more openings or orifices to facilitate the transmission of sound from the user to the microphone acoustic module  18 , which may also include a semi-permeable barrier such as screen mesh or protective element to inhibit ingress of liquid or other foreign matter as described with respect to speaker acoustic port  16  in  FIG. 3 . 
     In one embodiment depicted in  FIG. 3 , acoustic module  12  is a speaker module. As shown in  FIG. 3 , speaker acoustic module  12  includes various components for producing and transmitting sound, including a diaphragm  25 , a voice coil  26 , a center magnet  27 , and side magnets/coils  28 . In a typical implementation, the diaphragm  25  is configured to produce sound waves or an acoustic signal in response to a stimulus signal in the voice coil  26 . That is, a modulated stimulus signal in the voice coil  26  causes movement of the center magnet  27 , which is coupled to the diaphragm  25 . Movement of the diaphragm  25  creates the sound waves, which propagate through an acoustic cavity  28  of acoustic module  12  and eventually out acoustic port  16  to a region external to the device. In some cases, the acoustic cavity  28  functions as an acoustical resonator having a shape and size that is configured to amplify and/or dampen sound waves produced by movement of diaphragm  25 . 
     As shown in  FIG. 3 , the acoustic module  12  also includes a yoke  29 , connector elements  31 , and a cavity wall  32 . These elements provide the physical support of the speaker elements. Additionally, the connector elements  31  and the cavity wall  32  together form the partially enclosed acoustic cavity  28 . The specific structural configuration of  FIG. 3  is not intended to be limiting. For example, in alternative embodiments, the acoustic cavity may be formed from additional components or may be formed from a single component. 
     The acoustic module  12  depicted in  FIG. 3  is provided as one example of a type of speaker acoustic module. In other alternative implementations, the speaker module may include different configurations for producing and transmitting sound, including, for example, a vibrating membrane, piezoelectric transducer, vibrating ribbon, or the like. Additionally, in other alternative implementations, the acoustic module may be a microphone acoustic module having one or more elements for converting acoustic energy into an electrical impulse. For example, the acoustic module may alternatively include a piezoelectric microphone element for producing a charge in response to acoustic energy or sound. 
     As previously mentioned, because the acoustic port  16  connects the acoustic module  12  to the external environment, there is a possibility that liquid may accumulate or infiltrate the interior of the module. In some cases, even with the screen element  24  or other protective elements in place, liquid may enter the acoustic cavity  28  of the module. For example, if the device is immersed in a liquid or subjected to a liquid under pressure, some liquid ingress may occur. Additionally, naturally occurring moisture in the air may condense and accumulate over time resulting in the presence of liquid within the module. In such cases, the accumulation of liquid in, for example, the acoustic cavity  28 , may affect the performance of the acoustic module  28  by changing the acoustic dynamics of the cavity  28 , diaphragm  25 , or other elements of the acoustic module  12 . 
     Thus, in one embodiment, acoustic module  12  may include one or more elements configured to inhibit the entry of liquid into acoustic cavity  28  and facilitate the exit of any liquid that does enter acoustic cavity  28 . As shown in  FIG. 3 , protective screen  24  is located at opening  22  in the acoustic cavity  28 . In some embodiments, screen element  24  may be configured with one or more hydrophobic surfaces, such as one or more hydrophobic coatings (such as manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon-nanotubes, silica nano-coating, polytetrafluoroethylene, silicon, various flouropolymers, and so on). 
     As shown in  FIG. 3 , acoustic module  12  may also include a speaker formed from a diaphragm element  25  and a voice coil  26 . In cases where the acoustic module  12  includes a speaker, one or more acoustic energy pulses may be applied to further facilitate expulsion of liquid from the acoustic module  12 . In one example, the acoustic energy pulses may be generated at a frequency that is outside the audible range of a human ear. A typical range of acoustic frequencies that are audible to humans may be between 20 Hz and 20,000 Hz. Thus, the acoustic energy pulse(s) used to help expel the liquid may be less than 20 Hz or greater than 20,000 Hz. Generally, if an acoustic energy pulse is not audible to humans, a user may be unaware when such an acoustic pulse is being applied to remove liquid from the acoustic cavity  28 . 
     As shown in  FIG. 3 , acoustic module  12  may also include one or more sensors  33 . In some cases, sensor  33  may include a pressure sensor, an optical sensor, a moisture sensor, a conductive sensor, or the like. Sensor  33  may either directly or indirectly detect the presence of liquid in acoustic cavity  28 . For example, the sensor  33  may directly sense the presence of liquid in acoustic cavity  28  by detecting a change in optical, electrical, or moisture conditions as compared to reference condition when acoustic cavity  28  is evacuated or empty. In another example, sensor  33  may be an acoustic sensor and may indirectly detect the presence of liquid in acoustic cavity  28  by detecting a tone or acoustic pulse produced by the speaker or other acoustic element. In general, the presence of a liquid may dampen or alter the acoustic response of acoustic module  12 . The acoustic response may be measured using sensor  33  and compared to a reference response to detect the presence of liquid in acoustic cavity  28  or other portions of acoustic module  12 . In the example depicted in  FIG. 3 , sensor  33  is located proximate to acoustic cavity  28 . However, another type of sensor may be used that is not proximate to acoustic cavity  28  or not located within acoustic module  12 . For example, a microphone element of a microphone module may be used as a sensor, in some implementations. 
     Although portable electronic device  11  is illustrated and discussed as including controller unit  19  belonging to portable electronic device  11 , in some cases controller  19  may be integrated into acoustic module  12 . For example, in various implementations, acoustic module  12  may include a variety of additional components such as a controller that controls the speaker and other components to facilitate expulsion of liquid from the acoustic cavity. Additionally, although the examples provided above relate to an acoustic module having a speaker, similar elements and techniques could also be applied to an acoustic module having a microphone. 
     As described above, the use of hydrophobic mesh  24  may inhibit the entry of liquid into acoustic chamber  28 . However, this same hydrophobic mesh may also inhibit the removal of liquid from acoustic chamber  28 . As described above, the generation of acoustic energy pulses within acoustic module  12  may aid in moving liquid toward hydrophobic mesh portion  24  and opening  22 . However, the liquid resistance provided by hydrophobic mesh  24  in  FIG. 3  may make the removal process more difficult, insofar as the hydrophobic mesh may resist the expulsion of water therethrough. Accordingly and in some embodiments, an external surface of the screen element  24  may be configured to be hydrophobic and an internal surface of the screen element may be configured to be hydrophilic, such as utilizing one or more hydrophobic and/or hydrophilic coatings (such as polyethylene glycol and so on). Such hydrophobic external surfaces may resist the passage of liquids through the screen element from the external environment into the acoustic cavity  28  whereas the hydrophilic internal surfaces may aid the passage of liquids through the screen element from the acoustic cavity  28  toward the external environment. That is, the mesh may be manipulated such that the surface energy on one side of the mesh may be hydrophobic while the opposite side of the mesh may be more hydrophilic. 
     Referring to  FIG. 4 , a cross-sectional view of acoustic module  12  as described in  FIG. 3  depicting speaker acoustic module  12  and speaker acoustic port  16  taken along section A-A of  FIG. 1 . Speaker acoustic port  16  includes an opening  22  that facilitates the transmission of audible signals from acoustic module  12  to the user&#39;s ear. Orifice  22  through the housing  15  connects internal components of acoustic module  12  with the external environment. In this embodiment, screen  24  is replaced by a screen  34  having both hydrophobic and hydrophilic properties. That is, screen  34  includes a hydrophobic outer portion  35  adjacent to opening  36  and a hydrophilic inner portion  37  adjacent to the interior of acoustic cavity  28 . The addition of hydrophilic inner portion  37  attracts liquid from the interior of acoustic cavity  28  and facilitates the removal of that liquid through opening  36  in acoustic port  16 . 
     In some cases, additional optional operations may be performed to monitor the liquid removal process. For example, in some cases, a tone or acoustic signal may be generated by the speaker or other acoustic element of acoustic module  12 . Because the presence of liquid may affect the acoustic response of acoustic module  12 , the tone or acoustic signal may indicate the presence or quantity of liquid remaining in acoustic module  12 . In one example, acoustic sensor  33  (e.g., a microphone) may be used to measure and quantify the tone or acoustic signal. The measurement of the tone or acoustic signal produced by acoustic module  12  may be compared to a known reference measurement that represents the acoustic response of acoustic module  12  when dry. Based on the comparison between the measured response and the reference measurement, the presence of liquid can be detected, and/or the quantity of any remaining liquid may be estimated. 
     Referring to  FIG. 5 , a perspective view of outer screen portion  35  and inner screen portion  37  made of liquid permeable material is shown. In one embodiment, outer screen portion  35  may be made of fine mesh and thus hydrophobic while inner screen portion  37  may be a coarse or rough mesh and thus hydrophilic. Screen portions  35  and  37  may be laminated together to form a single unit. Liquid may be moved by capillary action from the coarse inner screen portion  37  to the fine mesh outer screen portion  35  thus facilitating its removal from acoustic chamber  28 . In general, in order to distinguish a fine mesh from a coarse mesh, the size of the openings between the mesh (which may be made of metal, nylon, or other synthetic materials) is used. 
     Various types of mesh sizing may be employed. For example, one example of mesh sizing is the US Standard sizing chart. Another is the so-called Tyler equivalent chart. For example, a #10 mesh Tyler Equivalent is identical to US Standard No. 12 mesh. This mesh equates to a wire width of approximately 0.8 mm and an opening size of approximately 1.7 mm. In general, the larger the mesh number, the smaller the opening size so a #20 Tyler Equivalent (US Standard No. 20) has an opening size of about 0.85 mm or half that of the #10 mesh (US Standard No. 12). In the present embodiment inner screen portion  37  may have a lower mesh number (larger sieve size) than outer screen portion  35  (smaller sieve size) such that inner screen portion  37  is more hydrophilic than outer screen portion  35  and conversely, outer screen portion  35  is more hydrophobic than inner screen portion  37 . 
     In another embodiment, as shown in  FIG. 6 , a single mesh portion  38  made of a liquid permeable material is shown with a hydrophobic outer side  39  and a hydrophilic inner side  41 . In this embodiment and as one example, mesh portion  38  may be a nylon base material dipped in a flouropolymer to increase its hydrophobicity. A plasma etching process, such as an oxygen (O 2 ) or argon (Ar) based plasma etching, may be used to etch inner side  41  of mesh portion  38  to make it more hydrophilic. 
     In certain embodiments, a hydrophilic layer such as silicon dioxide (SiO 2 ) or silicon nitride (SiN) may coat the inner surface to further increase the hydrophilicity of inner side  41 . The increase in the relative hydrophilicity may increase wetting of inner side  41  and facilitate movement of the liquid away from acoustic cavity  28  as described above. The hydrophilic layer may be deposited by physical vapor deposition, as one example. 
     Additional techniques may be applied to assist with the movement of the liquid. For example, if acoustic module  12  includes a speaker element, one or more acoustic energy pulses may be generated to help to drive a portion of the liquid toward one end of acoustic cavity  28  adjacent hydrophilic inner side  41 . The exact tone and/or energy of the acoustic pulse may vary with the amount of liquid in the cavity  28 , which may be determined through operation of the aforementioned sensor. 
     Referring to  FIG. 7 , a flow chart of a method for removing liquid from acoustic chamber  28  in portable electronic device  11  is illustrated. In operation  42  a screen having a hydrophobic side and a hydrophilic side is manufactured. In operation  43 , the screen is placed in an opening of a portable electronic device such that said hydrophobic side is adjacent the exterior of the portable electronic device and the interior side is adjacent the acoustic chamber in the portable electronic device. In operation  44 , the portable electronic device detects that liquid is present in the acoustic chamber and in operation  45 , the liquid is induced to move toward the hydrophilic side of the screen so as to be conducted to and through the hydrophilic side of the screen and the hydrophobic side of the screen and into the opening of the portable electronic device by wicking or capillary action through the screen. 
     Referring to  FIG. 8 , a method for manufacturing a cover for an acoustic module is shown. In operation  46  a liquid permeable synthetic material, such as nylon, having a first side and a second side is provided. In operation  47 , the liquid permeable material is coated with a hydrophobic coating, examples of which include manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon-nanotubes, silica nano-coating, polytetrafluoroethylene, silicon, or various flouropolymers. In operation  48 , in one embodiment, the hydrophobic coating may be removed from one side by plasma etching such as an oxygen or argon plasma process. In operation  49 , the side with the removed coating may be coated using physical vapor deposition with a hydrophilic coating such as silicon dioxide (SiO 2 ), polyethylene glycol or silicon nitride (SiN 1 ). 
     Referring to  FIG. 9 , an alternate embodiment of a method for manufacturing a cover for an acoustic module is illustrated. In operation  51 , a first synthetic mesh material such as nylon with a small mesh opening is provided. In operation  52 , in one embodiment, the first mesh material may be coated by physical vapor deposition or other techniques with a hydrophobic coating such as manganese oxide polystyrene, zinc oxide polystyrene, precipitated calcium carbonate, carbon-nanotubes, silica nano-coating, polytetrafluoroethylene, silicon, or various flouropolymers. In operation  53 , a second synthetic mesh material having a second size mesh opening smaller than the first size mesh opening is provided. In operation  54 , in one embodiment, the second mesh material may be coated by physical vapor deposition or other techniques with a hydrophilic coating such as silicon dioxide (SiO 2 ); polyethylene glycol; and silicon nitride (SiN 1 ). In operation  55 , the first mesh material and said second mesh material are laminated together to form the cover. 
     It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes. 
     While the present disclosure has been described with reference to various embodiments, it will be understood that these embodiments are illustrative and that the scope of the disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. More generally, embodiments in accordance with the present disclosure have been described in the context or particular embodiments. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow.

Metadata:
Filing Date: 20140902
Publication Date: 20170221
Grant Date: 20170221
Priority Date: 20140822
Inventors: WEBER DOUGLAS J.
MATSUYUKI NAOTO
Assignee: APPLE INC
CPC Classifications: [{"code": "B32B2307/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01J2237/3341", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2255/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B5/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2307/728", "inventive": false, "first": false, "tree": "[]"}, {"code": "B05D5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2307/73", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01J37/32394", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B37/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2305/38", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "G10K11/004", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2307/724", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2571/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/728", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2305/38", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2571/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R29/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "G10K11/004", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2307/73", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B05D5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B37/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01J37/32394", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/023", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2307/73", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/728", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2571/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2305/38", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "B05D5/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "G10K11/004", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 55347443