PATENT DOCUMENT

Publication Number: US-10063977-B2
Application Number: US-201615268138-A
Country: US
Kind Code: B2

Title: Liquid expulsion from an orifice

Abstract:
A device having one or more an acoustic modules. The acoustic module includes an acoustic element and a cavity that is acoustically coupled to the acoustic element. The module also includes a first conductive element that is configured to generate a first surface charge on a first region of an interior surface of the cavity. A second conductive element is configured to generate a second surface charge on a second region of the interior surface of the cavity. The first and second charge on the first and second regions of the interior surfaces of the cavity may be selectively applied to facilitate movement of a liquid held within the cavity.

Claims:
We claim: 
     
       1. An electronic device comprising:
 a housing; 
 a display in the housing; 
 an acoustic module in the housing, wherein the acoustic module includes an acoustic element, a voice coil, and a cavity that is acoustically coupled to the acoustic element, and wherein the acoustic element is configured to generate an acoustic pulse that facilitates movement of liquid within the cavity; and 
 a screen covering the cavity, wherein the screen is configured to prevent liquid ingress into the cavity and wherein the screen is configured to facilitate the expulsion of liquid out of the cavity. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the electronic device is a wearable device. 
     
     
       3. The electronic device defined in  claim 1 , wherein the acoustic element is configured to generate an additional acoustic pulse that facilitates movement of liquid within the cavity. 
     
     
       4. The electronic device defined in  claim 3 , wherein the cavity has an opening and wherein the acoustic pulse and the additional acoustic pulse expel at least a portion of the liquid from the cavity through the opening. 
     
     
       5. The electronic device defined in  claim 1 , wherein the acoustic element is a speaker element. 
     
     
       6. The electronic device defined in  claim 1 , wherein the acoustic pulse is at a frequency that is less than 20 Hz or greater than 20,000 Hz. 
     
     
       7. The electronic device defined in  claim 1 , wherein the cavity has an opening and wherein the acoustic pulse expels at least a portion of the liquid from the cavity through the opening. 
     
     
       8. An electronic device comprising:
 a housing; 
 a display in the housing; 
 an acoustic module in the housing, wherein the acoustic module comprises a speaker, a cavity that is acoustically coupled to the speaker, and an opening in the cavity, and wherein the speaker is configured to generate at least one pulse of acoustic energy that moves liquid in the cavity towards the opening; and 
 a screen in the opening, wherein the screen is configured to resist passage of liquids into the cavity and to aid passage of liquids out of the cavity. 
 
     
     
       9. The electronic device defined in  claim 8 , wherein the at least one pulse of acoustic energy that moves liquid in the cavity towards the opening comprises a plurality of pulses of acoustic energy that move liquid in the cavity towards the opening. 
     
     
       10. The electronic device defined in  claim 9 , wherein the plurality of pulses of acoustic energy include a pulse of acoustic energy at a frequency that is less than 20 Hz or greater than 20,000 Hz. 
     
     
       11. The electronic device defined in  claim 8 , wherein the speaker comprises a diaphragm. 
     
     
       12. The electronic device defined in  claim 11 , wherein the speaker comprises a voice coil. 
     
     
       13. The electronic device defined in  claim 8 , wherein the electronic device is a wearable device. 
     
     
       14. An electronic device comprising:
 a housing, wherein the housing has an opening; and 
 a speaker element in the housing, wherein the speaker element is configured to generate at least one pulse of acoustic energy that moves liquid in the electronic device towards the opening in the housing; 
 a screen in the opening, wherein the screen is configured to resist passage of liquid into the opening and wherein the screen is configured to aid passage of liquid out of the opening. 
 
     
     
       15. The electronic device defined in  claim 14 , wherein the electronic device is a wearable device. 
     
     
       16. The electronic device defined in  claim 14 , wherein the at least one pulse of acoustic energy comprises a plurality of pulses of acoustic energy and wherein the plurality of pulses of acoustic energy include a pulse of acoustic energy at a frequency that is less than 20 Hz or greater than 20,000 Hz. 
     
     
       17. The electronic device defined in  claim 14 , wherein the speaker element is formed in an acoustic module and wherein the acoustic module includes a cavity. 
     
     
       18. The electronic device defined in  claim 17 , further comprising:
 a processing unit; and 
 an acoustic sensor, wherein the speaker element is configured to generate a tone, wherein the acoustic sensor is configured to measure an acoustic response to the tone, and wherein the processing unit is configured to determine an amount of liquid in the cavity based on the measured acoustic response. 
 
     
     
       19. The electronic device defined in  claim 14 , further comprising:
 a processing unit; and 
 a sensor, wherein the processing unit is configured to use the sensor to detect a presence of the liquid in the opening.

Description:
This application claims priority to U.S. patent application Ser. No. 14/275,065 filed May 12, 2014, which is hereby incorporated by reference herein in its entirety. This application claims the benefit of and claims priority to patent application Ser. No. 14/275,065 filed May 12, 2014. 
     TECHNICAL FIELD 
     This disclosure relates generally to acoustic modules, and more specifically to expulsion of liquid from an acoustic cavity of an 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 partially exposed to the environment surrounding the device via one or more orifices or openings. 
     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 evacuating or removing moisture that has entered or accumulated in an acoustic module. 
     SUMMARY 
     The embodiments described herein are directed to an acoustic module that is configured to remove all or a portion of a liquid that has accumulated within a cavity of the acoustic modules. In one example embodiment, the acoustic modules includes an acoustic element and a cavity that is acoustically coupled to the acoustic element. The module also includes a first conductive element configured to generate a first surface charge on a first region of an interior surface of the cavity, and a second conductive element configured to generate a second surface charge on a second region of the interior surface of the cavity. In some cases, the first and second charge on the first and second regions of the interior surfaces of the cavity may be selectively applied to facilitate movement of a liquid held within the cavity. In some embodiments, the acoustic module is incorporated into an electronic device. 
     In one example, the first conductive element is formed from a first electrode that is proximate to an interior surface of the cavity, and the second conductive element is formed from a second electrode that is proximate to an interior surface of the cavity and proximate to the first electrode. In some cases, the first and second electrodes are separated from the interior surface of the cavity by a dielectric layer. 
     In one example, the first charge is a positive charge resulting in a decrease in the hydrophobicity of the first region of the interior of the surface of the cavity. In this case, the first charge may facilitate movement of the liquid toward the first region of the interior surface of the cavity. In some cases, the second charge is a negative charge resulting in an increase in the hydrophobicity of the second region of the interior of the surface of the cavity. One or both of the first and second charges may facilitate movement of the liquid toward the first region of the interior surface of the cavity. 
     In one example embodiment, the first and second conductive elements are located on a lower surface of the cavity. The acoustic module may also include a third conductive element configured to generate a first surface charge on a third region of an interior surface of the cavity. The third conductive element may be located on an upper surface of the cavity. The module may also include a fourth conductive element configured to generate a fourth surface charge on a fourth region of the interior surface of the cavity. In some cases, the first, second, third, and fourth charges may be selectively applied to facilitate movement of a liquid held within the cavity. 
     In one example embodiment, the first and second conductive elements are formed from an electrode that substantially conforms to the shape of the cavity. The first and second conductive elements may be coil elements formed from a coil of conductive wire. In some cases, the acoustic element is a speaker element. In some cases, 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 cavity. 
     In one example embodiment, the module also includes a screen element located at an opening in the cavity. The screen element may be configured to selectively apply a surface charge to a surface of the screen element to modify the hydrophobicity of the surface of the screen element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-B  depict an example 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. 3A  depicts a cross-sectional view of an example acoustic module taken along section A-A of  FIG. 1A . 
         FIG. 3B  depicts a cross-sectional view of an example acoustic module having conductive elements for expelling liquid from the acoustic module taken along section A-A of  FIG. 1A . 
         FIGS. 4A-C  depict an example system of conductive elements for moving liquid disposed in a cavity. 
         FIG. 5  depicts a flow chart or an example process for expelling liquid from a cavity. 
     
    
    
     DETAILED DESCRIPTION 
     The description that follows includes example systems and processes that embody various elements of the present disclosure. However, it should be understood that the described disclosure may be practiced in a variety of forms in addition to those described herein. 
     The present disclosure includes systems, techniques, and apparatuses for expelling liquid from a cavity of an acoustic module through an orifice or opening of the module. In one example, the hydrophobicity of one or more elements of the acoustic module may be varied by varying the electric charge on the one or more elements of the acoustic module. In some implementations, the electric charge may be varied on a series of elements, facilitating movement of a liquid held within the cavity. 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. 
       FIGS. 1A-B  depict an example device  100  including an acoustic module. In this example, the device  100  is a mobile telephone having a touch screen display  110 . The touch screen display  110  is an interface for the user to provide input to the device as well as present visual output to the user. In this example, the device  100  also includes interface buttons  112  for providing additional input to the device  100 . 
     As shown in  FIGS. 1A-B , the device  100  includes a housing  101  used to protect the internal components of the device  100 . The housing  101  may be formed from a substantially rigid shell structure that serves as the mechanical support for various components of the device  100 , including the touch screen display  110 , the interface buttons  112 , and one or more acoustic modules (depicted in  FIG. 2 ). 
     As shown in  FIGS. 1A-B , the housing  101  includes a first acoustic port  120  that is coupled to a speaker acoustic module. In this example, the speaker acoustic module is configured to function as an earpiece or speaker for the mobile telephone. An example acoustic module  303  is provided in  FIGS. 3A-B  depicting a cross-sectional view of a speaker acoustic module taken along section A-A of  FIG. 1A . The first acoustic port  120  includes an opening that facilitates the transmission of audible signals from the speaker to the user&#39;s ear. In this example, the acoustic port includes an orifice  116  through the housing  101  that connect internal components of the acoustic module with the external environment. In other examples, a single acoustic port may include multiple orifices. As described in more detail with respect to  FIG. 3 , the first acoustic port  120  may also include a screen mesh or other protective element configured to inhibit ingress of liquid or other foreign matter. The housing  101  also includes a second acoustic port  130  that is coupled to a microphone acoustic module that is configured to function as a mouthpiece or microphone for the mobile telephone. The second acoustic port  130  also includes one or more openings or orifices to facilitate the transmission of sound from the user to the microphone acoustic module, which may include a screen mesh or protective element to inhibit ingress of liquid or other foreign matter. 
     In this example, the device  100  is a smart phone. However, it is understood that the device  100  depicted in  FIGS. 1A-B  is simply one example and that other types of devices may include an acoustic module. Other types of devices include, without limitation, a laptop computer, a desktop computer, a cellular phone, a digital media player, a wearable device, a health-monitoring device, a tablet computer, a mobile computer, a telephone, and/or other electronic device. 
       FIG. 2  depicts a schematic diagram of example components of the device  100  that are located within the housing  101 . As shown in  FIG. 2 , the device  100  may include one or more processing units  154 , one or more non-transitory storage media  152 , one or more speaker acoustic modules  121 , and/or one or more microphone acoustic modules  131 . In this example, the processing unit includes a computer processor that is configured to execute computer-readable instructions to perform one or more electronic device functions. The computer-readable instructions may be stored on the non-transitory storage media  152 , which may include, without limitation: a magnetic storage medium; optical storage medium; magneto-optical storage medium; read only memory; random access memory; erasable programmable memory; flash memory; and the like. 
     As shown in  FIG. 2 , device  100  may also include two acoustic modules: a speaker acoustic module  121  and a microphone acoustic module  131 . The acoustic modules  121 ,  131  are coupled to respective acoustic ports (items  120  and  130  of  FIGS. 1A-B ). The acoustic modules  121 ,  131  are configured to transmit and/or receive signals in response to a command or control signal provided by the processing unit  154 . In some cases, intermediate circuitry may facilitate the electrical interface between the processing unit  154  and the acoustic modules  121 ,  131 . 
     Although  FIG. 2  illustrates the device  100  as including particular components, this is provided only as an example. In various implementations, the device  100  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, the device may include only one of a speaker acoustic module  121  and a microphone acoustic module  131 . Alternatively, the device may include additional acoustic modules or other types of acoustic modules 
       FIG. 3A  depicts a simplified schematic cross-sectional view of a first embodiment of a device having an acoustic module  303 . The cross-sectional view of  FIG. 3A  is taken along section A-A of  FIG. 1A . The cross-sectional view of  FIG. 3A  is not drawn to scale and may omit some elements for clarity. The acoustic module  303  may be, for example, a speaker acoustic module of an electronic device (See, e.g., item  121  of  FIG. 2 ). The electronic device may include a housing  301  in which the acoustic port  120  is formed. In the present example, the acoustic port includes a single passage or orifice  116  connecting the acoustic cavity  311  of the acoustic module  303  to an environment external to the electronic device. In other examples, a single port may include multiple orifices. A screen element  315  may separate the acoustic cavity from the external environment and may impede the ingress of liquids or other foreign material from the external environment into the acoustic module  303 . 
     In the present example depicted in  FIG. 3A , the acoustic module  303  is a speaker module. As shown in  FIG. 3A , a speaker acoustic module includes various components for producing and transmitting sound, including a diaphragm  310 , a voice coil  309 , a center magnet  308 , and side magnets/coils  307 . In a typical implementation, the diaphragm  310  is configured to produce sound waves or an acoustic signal in response to a stimulus signal in the voice coil  309 . That is, a modulated stimulus signal in the voice coil  309  causes movement of the center magnet  308 , which is coupled to the diaphragm  310 . Movement of the diaphragm  310  creates the sound waves, which propagate through the acoustic cavity  311  of acoustic module  303  and eventually out the acoustic port  120  to a region external to the device. In some cases, the acoustic cavity  311  functions as an acoustical resonator having a shape and size that is configured to amplify and/or dampen sound waves produced by movement of the diaphragm  310 . 
     As shown in  FIG. 3A , the acoustic module  303  also includes a yoke  306 , connector elements  312 , and a cavity wall  313 . These elements provide the physical support of the speaker elements. Additionally, the connector elements  312  and the cavity wall  313  together form the partially enclosed acoustic cavity  311 . The specific structural configuration of  FIG. 3A  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  303  depicted in  FIG. 3A  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  120  connects the acoustic module  303  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  315  or other protective elements in place, liquid may enter the acoustic cavity  311  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  311 , may affect the performance of the acoustic module  303  by changing the acoustic dynamics of the cavity  311 , diaphragm  310 , or other elements of the acoustic module  303 . 
     Thus, in some implementations, the acoustic module  303  may include one or more elements configured to expel water or liquid that accumulates in, for example, the acoustic cavity  311  of the module. In the present example, the acoustic module  303  includes one or more conductive elements configured to change the surface charge on portions of the acoustic module. As explained in more detail with regard to  FIG. 4 , below, the surface charge can facilitate movement and expulsion of the liquid from the acoustic cavity  311 . 
       FIG. 3B  depicts a cross-sectional view of an acoustic module  303  having conductive elements for expelling liquid from the module. The cross-sectional view of  FIG. 3B  is taken along section A-A of  FIG. 1A . In particular, the acoustic module  303  includes conductive elements ( 350   a - d ,  360   a - d ) located proximate to the interior surfaces of the acoustic cavity  311 . In this example, a first array of conductive elements  350   a - d  are located proximate to a lower region of the acoustic cavity  311 , and a second array of conductive elements  360   a - d  are located proximate to an upper region of the acoustic cavity  311 . Although one example configuration is depicted in  FIG. 3B , conductive elements may be arranged proximate to other surfaces of the acoustic cavity  311  or proximate to other components of the acoustic module  303  that may contain liquid. Also, in other embodiments, the number of elements, the size of the elements, and the shape of the elements may vary. Also, a series of conductive elements may be located only on one (e.g., the lower) interior surface of the acoustic cavity  311 . 
     In one example embodiment, each of the conductive elements ( 350   a - d ,  360   a - d ) are formed from a conductive material that is patterned into an individual electrode. In this case, the conductive elements will have a form factor that substantially conforms to a corresponding portion of the cavity. The electrodes may be formed, for example, by patterning a conductive material, such as indium tin oxide (ITO), copper, or silver on a flat, flexible substrate and then attaching the electrodes to an interior surface of the acoustic cavity  311 . In some cases, the electrodes are formed as part of a laminate material having a dielectric layer and an electrode layer. In this case, the laminate material may be inserted into the acoustic cavity  311  such that the electrode layer is positioned between the interior surface of the acoustic cavity  311  and the dielectric layer. This example arrangement places the electrodes proximate to liquid that may accumulate in the cavity, and also protects the electrodes from any liquid or moisture. The electrodes may also be coated by more than one dielectric layer and/or by a protective coating. In addition to protecting the electrodes, the dielectric layer or coating may also have surface properties that facilitate interaction with liquid that may accumulate within the cavity. 
     In another example, the conductive elements (e.g.  350   a - d ,  360   a - d ) may be formed from a series of coils. For example, the conductive elements  350   a  and  360   a  may represent a cross-sectional view of a single coil element formed by wrapping wire or other conductive element around a portion of the acoustic cavity  311 . In this case, the conductive elements will have a generally tube shaped form factor. Alternatively, the conductive elements may be formed as flat-plate coil elements. As discussed above with respect to the previous example, the coil conductive elements may also be protected from liquid by one or more dielectric layers and/or protective coatings. As previously mentioned, the dielectric layer or coating may also have surface properties that facilitate interaction with liquid that may accumulate within the cavity. 
     In general, each of the conductive elements ( 350   a - d ,  360   a - d ) of  FIG. 3B  are configured to generate a surface charge on a corresponding portion of the interior surface of the acoustic cavity  311 . In one example, each of the conductive elements ( 350   a - d ,  360   a - d ) is operatively coupled to circuitry that is configured to selectively apply a charge to one or more of the conductive elements ( 350   a - d ,  360   a - d ). In one example, the circuitry may be configured to selectively apply a DC voltage to each of the conductive elements to generate the surface charge. In another example, the circuitry may be configured to selectively apply an AC voltage or current to each of the conductive elements to generate the surface charge. 
     As described in more detail below with respect to  FIG. 4A-C , a positive, neutral, or negative relative surface charge may be applied using a conductive element to modify the hydrophobicity of a surface proximate to the conductive element. With reference to  FIG. 3 , a surface charge may be applied to the acoustic cavity  311  using a conductive element  350   a - d ,  360   a - d  to modify the hydrophobicity of a corresponding region of the acoustic cavity  311 . In general, a positive charge applied to a region (by a conductive element) may reduce the hydrophobic properties of that region, which may tend to promote wetting of that region by any liquid that is nearby that region. Conversely, a negative charge applied to a region (by a conductive element) may increase the hydrophobic properties of that region, which may tend to increase the contact angle and decrease wetting by any liquid in that region. The surface charge may be selectively applied using the conductive elements ( 350   a - d ,  360   a - d ) to facilitate movement of the liquid within the acoustic cavity  311 . 
     In some cases, the selective operation of the conductive elements ( 350   a - d ,  360   a - d ) may be used to transport any accumulated liquid toward or away from a region of the acoustic cavity  311 . In one example, the conductive elements ( 350   a - d ,  360   a - d ) are used to selectively apply a charge to the interior surface of the acoustic cavity  311  to propel any liquid toward the acoustic port  120  of the acoustic module  303 . The propelled liquid may then be expelled from the acoustic module  303  by propelling the liquid through the protective screen  315  and any openings or orifices  116  of the acoustic port  120 . 
     As shown in  FIGS. 3A-B , a protective screen  315  is located at an opening in the acoustic cavity  311 . In some cases, the screen element  315  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, and so on). In some cases, a charge may also be selectively applied to the screen  315  to modify the hydrophobic properties of that element. For example, to prevent ingress of water, a negative charge may be applied to the protective screen  315 , thereby increasing the hydrophobic properties of the screen  315  and repelling water away from the opening of the acoustic cavity  311 . 
     In another example, a positive charge may be applied to the protective screen  315 , thereby decreasing the hydrophobic properties of the screen, which may promote wetting of the opening of the acoustic cavity  311 . This may be advantageous when expelling water from the acoustic cavity  311  by drawing water to the opening and facilitating evacuation of the acoustic cavity  311 . In general, it may be advantageous to apply a positive charge to the screen  315  in conjunction with the selective application of charge using one or more of the conductive elements  350   a - d ,  360   a - d  within the cavity. Thus, in some cases, any accumulated liquid may be expelled from the orifice(s)  116  by selectively applying charge to both the interior surface of the acoustic cavity  311  and the screen  315 . 
     In various cases, an external surface of the screen element  315  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  311  whereas such hydrophilic internal surfaces may aid the passage of liquids through the screen element from the acoustic cavity to the external environment. The use of coatings may be combined with the selective application of a charge to the screen  315  to facilitate both the prevention of liquid ingress and the expulsion of liquid that may accumulate in the acoustic cavity  311 . 
     As shown in  FIGS. 3A-B , the acoustic module  303  may also include a speaker formed from a diaphragm element  310  and a voice coil  309 . In cases where the acoustic module includes a speaker, one or more acoustic energy pulses may be applied to further facilitate expulsion of liquid from the acoustic module  303 . 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  311 . 
     As shown in  FIG. 3B , the acoustic module may also include one or more sensors  314 . In some cases, sensor  314  may include a pressure sensor, an optical sensor, a moisture sensor, a conductive sensor, or the like. The sensor  314  may either directly or indirectly detect the presence of liquid in the acoustic cavity  311 . For example, the sensor  314  may directly sense the presence of liquid in the cavity  311  by detecting a change in optical, electrical, or moisture conditions as compared to reference condition when the acoustic cavity  311  is evacuated or empty. In another example, the sensor  314  is an acoustic sensor and may indirectly detect the presence of liquid in the acoustic cavity  311  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  303 . The acoustic response may be measured using the sensor  314  and compared to a reference response to detect the presence of liquid in the acoustic cavity  311  or other portions of the acoustic module  303 . In the example depicted in  FIG. 3B , the sensor  314  is located proximate to the cavity  311 . However, another type of sensor may be used that is not proximate to the cavity  311  or not located within the acoustic module  303 . For example, a microphone element of a microphone module may be used as a sensor, in some implementations. 
     Although a variety of different liquid removal elements (e.g., conductive elements, screen, speaker acoustic pulse) are discussed above and illustrated in the accompanying figures, it is understood that these are examples. In various implementations, one or more of the discussed liquid removal elements may be utilized in a single embodiment without departing from the scope of the present disclosure. 
     Further, although the electronic device is illustrated and discussed as including a processing unit and a non-transitory storage medium (e.g., elements  154  and  152  of  FIG. 2 ) as belonging to the device, in some cases these elements may be integrated into the acoustic module. For example, in various implementations, the acoustic module may include a variety of additional components such as a controller that controls the speaker, the charge applied to respective elements of the acoustic module, and/or control 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. 
       FIGS. 4A-C  depict an example system of conductive elements for transporting liquid in a cavity. The elements and techniques discussed with respect to  FIGS. 4A-C  may be applied to facilitate movement of a liquid within an acoustic cavity, as described above with respect to  FIGS. 3A-B . In particular,  FIGS. 4A-C  depict an example of movement of a drop of liquid within a cavity having a plurality of conductive elements located proximate to an internal surface of the cavity. 
       FIGS. 4A-C  depict a drop of water  401  (example liquid) disposed within a cavity  411 . As shown in  FIGS. 4A-C , the cavity  411  includes a plurality of conductive elements  450 ,  460 ,  470  that are configured to apply a charge to an interior surface of the cavity  411 . In this example, the conductive elements  450 ,  460  are electrodes formed from a conductive material, such as ITO, copper, or silver. In this particular example, the width of the lower electrodes  450 ,  460  are approximately the same as the height of the cavity  411 . In other examples, the width of the lower electrodes may vary with respect to the height of the cavity  411 . 
     As shown in  FIG. 4A , the conductive elements  450 ,  460 ,  470  are formed as part of a laminate structure having a dielectric layer  421  and a hydrophobic layer  422 . The dielectric layer  421  may be formed from a dielectric sheet material, including a polymide sheet, polyester sheet, mylar sheet, or the like. The hydrophobic layer  422  may be formed from a silicone sheet, fluorocarbon polymer sheet, other hydrophobic material, or a material that is coated with a hydrophobic coating. In some cases, the hydrophobic layer  422  is processed or treated to increase the hydrophobic properties of the surface. For example, the hydrophobic layer  422  may have a coating or be treated to form a micro textured-surface. 
     In other examples, additional layers may also be used, including, for example, a pressure sensitive adhesive (PSA) layer, a structural stiffener layer, or additional dielectric and/or hydrophobic layers. In some cases, the dielectric and hydrophobic layers are formed as a single layer from a single material having appropriate dielectric and hydrophobic properties. In yet another example, a hydrophobic layer may be omitted from one or both of the surfaces of the cavity  411 . In yet another example, the conductive elements may be formed directly on the inner surface of the cavity. 
     As shown in  FIG. 4A , both the upper and lower surfaces of the cavity  411  are lined with a hydrophobic layer. Alternatively, in some cases, one layer or both layers may be lined with a hydrophilic layer or hydro-neutral layer. 
     As shown in  FIGS. 4A-C , a charge is selectively applied to the surface of the cavity  411  using the conductive elements  450 ,  460 ,  470  to transport the drop of water  401  through the cavity  411 . More specifically, by selectively applying a charge to a region of the surface of the cavity  411 , the relative surface energy of region may be changed altering the hydrophobic/hydrophilic properties of that region. In general, the shape of a liquid drop on a surface is determined, in part, by the interaction between the internal cohesive forces of the liquid (e.g., water) and the surface energy of the surface. In general, an electric charge increases the hydrophilic properties of the surface resulting in a decrease in the contact angle between a drop of water and the surface. This may also be described as a decrease in the hydrophobic properties of the surface. Additionally, by selectively applying a different electric charge or grounding an adjacent region on the surface, a non-uniform field may be formed across the liquid drop resulting in a different contact angle of the liquid drop near the adjacent region. By selectively applying charge and altering the hydrophobic/hydrophilic properties of the surface, a water drop can be drawn away from a first (hydrophobic) region and drawn toward a second (hydrophilic) region resulting in a movement of the water drop. 
     In some cases, a hydrophobic layer is omitted and the hydrophobic properties of the cavity are determined primarily by the charge applied to the surface of the corresponding region. In addition, one or more regions may be made substantially hydro-neutral through a combination of the cavity wall material properties and an applied charge. 
       FIG. 4A  depicts the water drop  401  disposed between a top conductive element  470  and a bottom conductive element  450 . In the example depicted in  FIG. 4A , a charge is not applied using the conductive elements. Thus, the contact angle of the drop of water is determined by the natural surface energy of the surface of the cavity. In this case, the surface of the cavity is a hydrophobic material having a relatively low surface energy. As a result, the water drop  401  is characterized by having a relatively high contact angle. 
       FIG. 4B  depicts the water drop  401  disposed between the top conductive element  470  and both of the lower conductive elements  450 ,  460 . In the example depicted in  FIG. 4B , an electrical (positive) charge is applied the conductive element  460  as compared to the neutral charge of conductive element  450 . A different (negative) charge is also applied to a portion of the upper surface using the upper conductive element  470 . Due to the increased surface energy produced using the conductive element  460 , the contact angle of the right-side of the water drop  401  is reduced. Simultaneously, the water drop  401  minimizes or reduces wetting of the upper surface due to the different charge that is applied by the conductive element  470 . As a result, the drop of water  401  is induced to wet the portion of the surface proximate to the lower conductive element  460  and move away from lower conductive element  450 . In some cases, a different (negative) charge may also be applied to the lower conductive element  450  to increase the contact angle of the respective portion of the water drop  410  and further facilitate the movement of the water drop  401  toward the other lower conductive element  460 . In some cases, it is not necessary to apply a different or negative charge to the upper conductive element  470  in order to facilitate movement of the water drop  401 . 
       FIG. 4C  depicts the water drop  401  disposed between a top conductive element  470  and the bottom conductive element  460 . In the example depicted in  FIG. 4C , a charge is not applied using the conductive elements. Thus, the contact angle of the drop of water is determined by the natural surface energy of the surface of the cavity. In this case, the surface of the cavity is a hydrophobic material having a relatively low surface energy and the water drop  401  is characterized by having a relatively high contact angle. 
     The sequence depicted in  FIGS. 4A-C  may be repeated for a series of conductive elements that are arranged along the interior surface of a cavity. In this way, a drop of water can be transported from one region of a cavity to another region. In the case of an acoustic cavity (for example, as depicted above in  FIGS. 3A-B ), a charge may be selectively applied to conductive elements to transport water (or another liquid) along the acoustic cavity and expel the water through an orifice at an opening of the cavity. 
       FIG. 5  depicts an example process  500  for expelling a liquid from a cavity of an acoustic module. The process  500  may be implemented, for example, using the acoustic cavity depicted in  FIGS. 3A-B . More generally, process  500  may be applied to a variety of acoustic modules, including, for example, both speaker- and microphone-type acoustic modules. 
     In operation  502 , the presence of liquid is detected. In one example, one or more sensors are used to detect the presence of liquid within the cavity or other portion of an acoustic module. An example sensor is discussed above with respect to  FIGS. 3A-B , above. As previously discussed, the sensor may include a pressure sensor, an optical sensor, a moisture sensor, a conductive sensor, or the like. In some embodiments, the microphone element of the device is used as an acoustic sensor to detect the presence of liquid in the acoustic module. The sensor may be used to directly or indirectly detect the presence of liquid in the acoustic module. For example, the sensor may directly sense the presence of liquid in the module by detecting a change in optical, electrical, or moisture conditions as compared to reference conditions when the module is dry. In another example, an acoustic sensor may be used and may indirectly detect the presence of liquid in the acoustic cavity 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 an acoustic module. The acoustic response may be measured using the sensor and compared to a reference response to detect the presence of liquid in the acoustic cavity or other portions of the acoustic module. As discussed previously, a microphone element of a microphone module may also be used as a sensor for purposes of operation  502 . 
     If the presence of liquid is detected in operation  502 , operation  504  is performed. In operation  504 , a charge is applied to an element of the acoustic module. In one example, a charge is applied to a portion of an interior surface of a cavity of the acoustic module. For example, a surface charge may be applied using at least one conductive element that is proximate to the interior surface. Typically, the surface charge changes the hydrophobicity of the surface due to the change in surface energy caused by the application of a surface charge. 
     In some cases, a charge is applied to a series of conductive elements in a synchronized manner. For example, a series of conductive elements may be arranged along a direction of the surface of the cavity. A charge may be applied to each of the conductive elements in sequence resulting in a surface charge that moves along the direction of the surface. Additionally, multiple charges may be simultaneously applied using multiple conductive elements arranged along the surface of the cavity. 
     In operation  506 , the liquid is moved within the cavity. As discussed above with respect to  FIGS. 4A-C , applying a charge to a region of a surface of the cavity may change the hydrophobicity of that region of the surface. By selectively applying a charge using one or more conductive elements, the change in hydrophobicity may tend to change the contact angle of a respective portion of the liquid tending to move it toward or away from a corresponding region of the surface. In one example, a positive charge is applied using a first conductive element to reduce the hydrophobicity of a corresponding region of the cavity. The decrease in the relative hydrophobicity may draw or attract liquid to that region by decreasing the contact angle and promoting wetting of the region. In addition, a different charge may be applied to a second conductive element that is proximate to the first conductive element resulting in a relative increase in the hydrophobicity of a corresponding region of the cavity. The increase in the relative hydrophobicity may increase the contact angle, decreasing wetting of the region and facilitate movement of the liquid way from that region and toward an area of lower hydrophobicity. Thus, selective application of a charge in operation  504  can be used to move the liquid within the cavity. 
     In some cases, a series of conductive elements are used to sequentially apply a charge down a length of the cavity. In this case, the charge, and thus the change in hydrophobic properties, may propagate along the surface like a wave. The charge wave may be used to drive a portion of the liquid along the length of the cavity. In some cases, multiple charge waves are used to drive the liquid toward one end of the cavity. 
     In some cases, one or more conductive elements may be used to generate a charge that draws a portion of the liquid toward the acoustic element (e.g., speaker). In this case, some of the liquid can be held back, while the remainder of the liquid is drawn toward the opening of the cavity for expulsion. This technique may be advantageous when, for example, the volume of liquid trapped in the cavity is too large to efficiently evacuate all at once. In some cases, this technique is repeated resulting in small portions of liquid being moved toward the opening of the cavity, while some portion of liquid is held back against the acoustic element or other region of the cavity. 
     As part of operation  506 , additional techniques may be applied to assist with the movement of the liquid. For example, if the acoustic module includes a speaker element, one or more acoustic energy pulses may be generated in conjunction with the application of the charge in operation  504 . In some cases, the one or more acoustic pulses helps to drive a portion of the liquid toward one end of the cavity. In another example, a positive charge may be applied to the protective screen or other element to facilitate movement of the liquid toward the opening of the cavity. 
     In operation  508 , at least a portion of the liquid is expelled from the cavity through an orifice. In one example, the movement of the liquid of operation  506  is sufficient to drive at least a portion of the liquid out of the cavity. In some cases, multiple techniques are applied to expel the liquid from the cavity and through the orifice. For example, a charge may be applied using one or more conductive elements that are located proximate to the opening of the cavity. In conjunction, a positive surface charge may be selectively applied to modify the hydrophobic properties of the protective screen. For example, a positive charge may be applied to the protective screen, reducing the hydrophobic properties of the screen, thereby facilitating passage of liquid through the screen. Additionally, one or more acoustic energy pulses may be generated facilitating the expulsion of at least a portion of the liquid through an orifice and out of the acoustic cavity. 
     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 the acoustic module. Because the presence of liquid may affect the acoustic response of the acoustic module, the tone or acoustic signal may indicate the presence or quantity of liquid remaining in the acoustic module. In one example, an acoustic sensor (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 the acoustic module may be compared to a known reference measurement that represents the acoustic response of the acoustic module 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. 
     In some cases, one or more operations of process  500  may be repeated based on a detected presence of liquid remaining in the acoustic module. In some cases, one or more operations of process  500  are performed until there is no longer liquid detected in the acoustic module. 
     Although the method is illustrated and described above as including particular operations performed in a particular order, it is understood that this is an example. In various implementations, various configurations of the same, similar, and/or different operations may be performed without departing from the scope of the present disclosure. 
     By way of a first example, the process  500  is illustrated and described as performing liquid extraction operations in response to the detection of the presence of liquid in the acoustic cavity of the acoustic module. Alternatively, the liquid extraction operations  504 ,  506 , and  508  may be performed without detecting the presence of liquid in the acoustic cavity. For example, one or more of the liquid extraction operations  504 ,  506 , or  508  may be performed on a regular interval to prevent or reduce the accumulation of liquid in the acoustic module. Additionally, one or more of the liquid extraction operations  504 ,  506 , or  508  may be performed when the device is idle or being charged. 
     By way of a second example, the process  500  is illustrated and described as performing a liquid extraction operation within a cavity of an acoustic module. However, the operations of process  500  may also be used to evacuate other regions of an acoustic module. Furthermore, the operations of process  500  may be performed on other types of enclosed cavities that are not associated with an acoustic module. 
     In the present disclosure, the methods disclosed may be implemented as sets of instructions or software readable by a device. Further, it is understood that the specific order or hierarchy of steps in the methods disclosed are examples of sample approaches. In other embodiments, the specific order or hierarchy of steps in the method can be rearranged while remaining within the disclosed subject matter. The accompanying method claims present elements of the various steps in a sample order, and are not necessarily meant to be limited to the specific order or hierarchy presented. 
     The described disclosure may be provided as a computer program product or software, that may include a non-transitory machine-readable medium having stored thereon instructions, which may be used to program a computer system (or other electronic device) to perform a process according to the present disclosure. A non-transitory machine-readable medium includes any mechanism for storing information in a form (e.g., software, processing application) readable by a machine (e.g., a computer). The non-transitory machine-readable medium may take the form of, but is not limited to, a magnetic storage medium (e.g., floppy diskette, video cassette, and so on); optical storage medium (e.g., CD-ROM); magneto-optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; and so on. 
     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: 20160916
Publication Date: 20180828
Grant Date: 20180828
Priority Date: 20140512
Inventors: ZADESKY, STEPHEN P.
ROTHKOPF, FLETCHER R.
FLETCHER, ASHLEY E.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R29/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/083", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/083", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/083", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/15", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R29/003", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 54368992