PATENT DOCUMENT

Publication Number: US-10587942-B1
Application Number: US-201816146983-A
Country: US
Kind Code: B1

Title: Liquid-resistant packaging for electro-acoustic transducers and electronic devices

Abstract:
A liquid-resistant microphone assembly includes a substrate defining a sound-entry region and a microphone transducer coupled with the substrate. The transducer has a sound-responsive region acoustically coupled with the sound-entry opening defined by the substrate. A liquid-resistant port membrane spans across the sound-entry opening defined by the substrate. The membrane is gas-permeable. An adhesive layer is positioned between the substrate and the liquid-resistant port membrane, coupling the liquid-resistant port membrane with the substrate and spacing the liquid-resistant port membrane from the substrate to form a gap between the membrane and the substrate. The adhesive layer defines an aperture having a periphery extending around and positioned outward of the sound-entry region. Modules and electronic devices incorporating such a microphone transducer also are disclosed.

Claims:
We currently claim: 
     
       1. A liquid-resistant microphone assembly comprising:
 a first substrate defining opposed first and second major surfaces and a sound-entry region extending through the substrate from the first major surface to the second major surface; 
 a microphone transducer coupled with the first substrate and having a sound-responsive region; 
 a liquid-resistant port membrane spanning across the sound-entry opening defined by the first substrate; 
 an adhesive layer positioned between the second major surface of the first substrate and the liquid-resistant port membrane, coupling the liquid-resistant port membrane with the second major surface of the first substrate and spacing the liquid-resistant port membrane from the second major surface of the substrate, forming a gap between the membrane and the second major surface of the first substrate, wherein the adhesive layer defines an aperture having a periphery extending around the sound-entry region and positioned outward of the sound-entry region; 
 a second substrate positioned opposite the first substrate relative to the port membrane; and 
 a housing extending from a first end to an opposed second end, wherein the housing defines a duct extending from the first end of the housing to the second end of the housing, wherein the second end of the housing sealably couples with the second substrate at a region outward of the sound-entry opening. 
 
     
     
       2. The liquid-resistant microphone assembly according to  claim 1 , wherein the microphone transducer comprises a MEMS microphone transducer. 
     
     
       3. The liquid-resistant microphone assembly according to  claim 1 , wherein the sound entry region comprises a plurality of apertures extending from the first major surface of the substrate to the second major surface of the substrate, wherein each aperture acoustically couples with the sound-responsive region of the microphone transducer. 
     
     
       4. The liquid-resistant microphone assembly according to  claim 1 , wherein the microphone transducer is coupled to the first major surface of the substrate. 
     
     
       5. The liquid-resistant microphone assembly according to  claim 1 , wherein the microphone transducer is coupled with the substrate at a position between the first major surface and the second major surface. 
     
     
       6. The liquid-resistant microphone assembly according to  claim 1 , wherein the second substrate is adhesively coupled with the first substrate. 
     
     
       7. The liquid-resistant microphone assembly according to  claim 6 , wherein the adhesive layer comprises a first adhesive layer, the liquid-resistant microphone assembly further comprising a second adhesive layer positioned between the liquid-resistant port membrane and the second substrate, coupling the second substrate to the liquid-resistant port membrane. 
     
     
       8. The liquid-resistant microphone assembly according to  claim 1 , wherein the sound-entry opening comprises a first sound-entry opening, the second substrate defines a second sound-entry opening acoustically coupled with the first sound-entry opening and the sound-responsive region of the microphone transducer. 
     
     
       9. The liquid-resistant microphone assembly according to  claim 8 , wherein the first sound-entry opening has a corresponding first characteristic dimension and the second sound-entry opening has a corresponding second characteristic dimension, wherein the second characteristic dimension is greater than the first characteristic dimension. 
     
     
       10. The liquid-resistant microphone assembly according to  claim 9 , wherein the aperture through the first adhesive layer has a characteristic dimension larger than the characteristic dimension of the first sound-entry opening and larger than the characteristic dimension of the second sound-entry opening. 
     
     
       11. The liquid-resistant microphone assembly according to  claim 9 , wherein the second adhesive layer defines an aperture having a characteristic dimension larger than the characteristic dimension of the first sound-entry opening and larger than the characteristic dimension of the second sound-entry opening. 
     
     
       12. The liquid-resistant microphone assembly according to  claim 8 , further comprising an acoustic mesh spanning across the second sound-entry opening. 
     
     
       13. The liquid-resistant microphone assembly according to  claim 1 , further comprising an acoustic mesh spanning across the duct at a position between the first end of the housing and the second end of the housing. 
     
     
       14. A microphone module, comprising:
 an interconnect substrate having a plurality of electrical conductors and defining a first aperture; and 
 a liquid-resistant microphone package having:
 a package substrate comprising a plurality of electrical contacts, each electrical contact electrically coupling with a corresponding electrical conductor in the interconnect substrate, the package substrate defining a first major surface, an opposed second major surface, and a sound-entry region having a corresponding periphery, wherein the sound-entry region is positioned adjacent the second major surface, the plurality of electrical contacts are exposed from the first major surface, and the interconnect substrate is positioned adjacent the first major surface; 
 a microphone transducer coupled with the package substrate; 
 a liquid-resistant membrane; 
 an adhesive layer positioned between the membrane and the package substrate, 
 
 the adhesive layer defining a second aperture having a corresponding periphery larger than the periphery of the sound-entry region defined by the package substrate and adhesively securing the membrane to the package substrate such that the membrane spans across and is spaced apart from the sound-entry region; and 
 a lid overlying the microphone transducer adjacent the first major surface, wherein the lid extends through the first aperture. 
 
     
     
       15. An electronic device, comprising:
 an enclosure having a wall, wherein the wall defines an acoustic port; 
 a liquid-resistant microphone assembly having a microphone transducer defining a sound-responsive region and a package substrate defining a liquid-resistant sound-entry region acoustically coupling the sound-responsive region with the acoustic port, wherein a periphery around the liquid-resistant sound-entry region sealably couples with a periphery around the acoustic port; 
 wherein the package substrate comprises a laminated construct comprising:
 a first substrate layer defining a perforated region corresponding to the sound-entry region and having a corresponding periphery, wherein the microphone transducer is coupled with the first substrate layer such that the sound-responsive region of the microphone transducer is exposed to the sound-entry region; 
 a liquid-resistant membrane layer spanning across the sound-entry region; 
 a first adhesive layer positioned between the first substrate layer and the membrane layer, adhesively coupling the membrane layer with the first substrate layer, wherein the first adhesive layer defines an aperture having a periphery extending around and positioned outward of the sound-entry region, forming a gap positioned between the membrane layer and the first substrate layer within the sound-entry region of the package substrate; 
 a second substrate layer positioned opposite the first substrate layer relative to the membrane layer, wherein the second substrate layer defines a perforated region acoustically coupled with the sound-responsive region of the microphone transducer, wherein the perforated region defined by the second substrate region has a corresponding periphery larger than the periphery of the perforated region of the first substrate; and 
 a second adhesive layer positioned between the second substrate layer and the membrane layer, wherein the second adhesive layer adhesively couples the second substrate layer with the membrane layer, wherein the second adhesive layer defines a corresponding aperture having a periphery, wherein the periphery of the second adhesive layer is positioned outward of the periphery of the perforated region of the first substrate layer and outward of the periphery of the perforated region of the second substrate layer. 
 
 
     
     
       16. The microphone module according to  claim 14 , wherein the microphone transducer is coupled to the first major surface of the package substrate. 
     
     
       17. The microphone module according to  claim 14 , wherein the microphone transducer is coupled with package substrate at a position between the first major surface and the second major surface. 
     
     
       18. The microphone module according to  claim 14 , wherein the package substrate comprises a first substrate layer, the microphone module further comprising a second substrate layer positioned opposite the first substrate layer relative to the liquid-resistant membrane. 
     
     
       19. The microphone module according to  claim 18 , wherein the microphone transducer has a sound-responsive region, wherein the sound-entry region comprises a first sound-entry region, wherein the second substrate defines a second sound-entry region acoustically coupled with the first sound-entry region and the sound-responsive region of the microphone transducer. 
     
     
       20. The microphone module according to  claim 19 , further comprising an acoustic mesh spanning across the second sound-entry opening. 
     
     
       21. The microphone module according to  claim 14 , further comprising an acoustic mesh positioned opposite the package substrate relative to the liquid-resistant membrane, wherein the acoustic mesh is spaced apart from the liquid-resistant membrane, defining a gap between the acoustic mesh and the sound-entry region. 
     
     
       22. The electronic device according to  claim 15 , further comprising a housing extending from a first end to an opposed second end, wherein the housing defines a duct extending from the first end of the housing to the second end of the housing, wherein the second end of the housing sealably couples with the second substrate at a region outward of the sound-entry opening, wherein the first end of the housing sealably couples with the wall, coupling the duct with the acoustic port. 
     
     
       23. The electronic device according to  claim 15 , further comprising an acoustic mesh spanning across the duct.

Description:
FIELD 
     This application and related subject matter (collectively referred to as the “disclosure”) generally concern liquid-resistant packaging for electronic devices, electro-acoustic transducers, and related systems. 
     BACKGROUND INFORMATION 
     In general, sound (sometimes also referred to as an acoustic signal) constitutes a vibration that propagates through a carrier medium, such as, for example, a gas, a liquid, or a solid. An electro-acoustic transducer, in turn, is a device configured to convert an incoming acoustic signal to an electrical signal, or vice-versa. Thus, an acoustic transducer in the form of a loudspeaker can convert an incoming signal (e.g., an electrical signal) to an emitted acoustic signal, while an acoustic transducer in the form of a microphone can be configured to convert an incoming acoustic signal to an electrical (or other) signal. 
     Some electronic devices that incorporate an electro-acoustic transducer may be exposed to environments other than dry air, such as, for example, rain, or may be fully immersed in a liquid. As an example, users of some electronic devices may wish to fully immerse their electronic device in water during certain activities (e.g., when participating in a water sport, like swimming, surfing, rafting, wake boarding, etc.) Nonetheless, intrusion of water or another liquid into an electronic device can damage components in the device, including electro-acoustic transducers. 
     SUMMARY 
     Concepts, systems, methods, and apparatus disclosed herein overcome many problems in the prior art and address one or more of the aforementioned or other needs. For example, this application describes a variety of liquid-resistant packages, e.g., for microphone transducers (or other components), suitable to inhibit intrusion of water or other liquids past a selected package boundary. Such packages can be combined into an electronic device to inhibit intrusion of water into the electronic device, making the electronic device liquid resistant. As well, some disclosed substrates are compatible with liquid-resistance tests prior to final assembly with a liquid-sensitive component (e.g., a microphone transducer). By allowing testing prior to final assembly, yields of liquid-resistant modules (e.g., microphone modules) can be increased at final assembly. 
     According to a first aspect, a liquid-resistant microphone assembly includes a substrate defining opposed first and second major surfaces. A sound-entry region extends through the substrate from the first major surface to the second major surface. A microphone transducer couples with the substrate and has a sound-responsive region acoustically coupled with the sound-entry opening defined by the substrate. A liquid-resistant port membrane spans across the sound-entry opening defined by the substrate. The membrane is gas-permeable. An adhesive layer is positioned between the second major surface of the substrate and the liquid-resistant port membrane, coupling the liquid-resistant port membrane with the second major surface of the substrate. The liquid-resistant port membrane is spaced from the second major surface of the substrate according to a thickness of the adhesive layer, forming a gap between the membrane and the second major surface of the substrate. The adhesive layer defines an aperture having a periphery extending around the sound-entry region and positioned outward of the sound-entry region. 
     An acoustic mesh can be positioned opposite the substrate relative to the liquid-resistant port membrane. The acoustic mesh can be spaced apart from the liquid-resistant port membrane in a region adjacent the sound-entry opening. 
     In an embodiment, the microphone transducer comprises a MEMS microphone transducer. 
     The sound entry region can include a plurality of apertures extending from the first major surface of the substrate to the second major surface of the substrate. Each aperture can acoustically couple with the sound-responsive region of the microphone transducer. 
     In an embodiment, the microphone transducer can couple to the first major surface of the substrate. 
     In another embodiment, the microphone transducer can couple with the substrate at a position between the first major surface and the second major surface. 
     In an embodiment, the substrate according to the first aspect can be a first substrate, and the liquid-resistant microphone assembly can also include a second substrate positioned opposite the first substrate relative to the port membrane. 
     In an embodiment, the second substrate is adhesively coupled with the first substrate. For example, the adhesive layer of the first aspect can be a first adhesive layer, and the liquid-resistant microphone assembly can further include a second adhesive layer positioned between the liquid-resistant port membrane and the second substrate, coupling the second substrate to the liquid-resistant port membrane. 
     The sound-entry opening can be a first sound-entry opening, and the second substrate can define a second sound-entry opening acoustically coupled with the first sound-entry opening, as well as the sound-responsive region of the microphone transducer. 
     The first sound-entry opening has a corresponding first characteristic dimension and the second sound-entry opening has a corresponding second characteristic dimension. The second characteristic dimension can be greater than the first characteristic dimension. 
     As well, the aperture through the first adhesive layer can have a characteristic dimension larger than the characteristic dimension of the first sound-entry opening and larger than the characteristic dimension of the second sound-entry opening. 
     Similarly, the second adhesive layer can define an aperture having a characteristic dimension larger than the characteristic dimension of the first sound-entry opening and larger than the characteristic dimension of the second sound-entry opening. 
     An acoustic mesh can span across the second sound-entry opening. 
     In an embodiment, a housing can extend from a first end to an opposed second end. The housing defines a duct extending from the first end of the housing to the second end of the housing, and the second end of the housing sealably couples with the first substrate at a region outward of the sound-entry opening. An acoustic mesh can span across the duct at a position between the first end of the housing and the second end of the housing. 
     According to a second aspect, a microphone module includes an interconnect substrate having a plurality of electrical conductors. A liquid-resistant microphone package having a package substrate and a microphone transducer couples with the package substrate. The package substrate defines a sound-entry region having a corresponding periphery. The package also has a liquid-resistant and gas-permeable membrane. An adhesive layer positioned between the membrane and the package substrate defines an aperture having a corresponding periphery larger than the periphery of the sound-entry region defined by the package substrate. The adhesive layer adhesively secures the gas-permeable membrane to the package substrate such that the membrane spans across and is spaced apart from the sound-entry region. The package substrate also has a plurality of electrical contacts, and each electrical contact is electrically coupled with a corresponding electrical conductor in the interconnect substrate. 
     The package substrate can define a first major surface and an opposed second major surface. The sound-entry opening can be positioned adjacent the second major surface. The liquid-resistant microphone package can also include a lid overlying the microphone transducer adjacent the first major surface. The plurality of electrical contacts can be exposed from the first major surface and the interconnect substrate can be positioned adjacent the first major surface of the package substrate. 
     The interconnect substrate can define an aperture and the lid of the liquid-resistant microphone package can extend through the aperture. 
     According to another aspect, an electronic device includes an enclosure having a wall, and the wall defines an acoustic port. The electronic device also includes a liquid-resistant microphone assembly having a microphone transducer. The transducer defines a sound-responsive region. The microphone assembly also includes a package substrate defining a liquid-resistant sound-entry region acoustically coupling the sound-responsive region with the acoustic port. A periphery around the liquid-resistant sound-entry region sealably couples with a periphery around the acoustic port. The package substrate is a laminated construct including a substrate layer. The microphone transducer couples with the first substrate layer such that the sound-responsive region of the microphone transducer is exposed to the sound-entry region. A liquid-resistant, gas-permeable membrane layer spans across the sound-entry region. An adhesive layer is positioned between the substrate layer and the membrane layer, adhesively coupling the membrane layer with the substrate layer. The adhesive layer defines an aperture having a periphery extending around and positioned outward of the sound-entry region, forming a gap positioned between the membrane layer and the substrate layer within the sound-entry region of the package substrate. 
     In an embodiment of the electronic device, the substrate layer is a first substrate layer, defining a perforated region corresponding to the sound-entry region and having a corresponding periphery. In the embodiment, the adhesive layer is a first adhesive layer, and the package substrate further includes a second substrate layer and a second adhesive layer. The second substrate layer can be positioned opposite the first substrate layer relative to the membrane layer. The second substrate layer can define a perforated region acoustically coupled with the sound-responsive region of the microphone transducer. The perforated region defined by the second substrate region can have a corresponding periphery larger than the periphery of the perforated region of the first substrate. The second adhesive layer can be positioned between the second substrate layer and the membrane layer. The second adhesive layer can adhesively couple the second substrate layer with the membrane layer, and the second adhesive layer can define a corresponding aperture having a periphery. The periphery of the second adhesive layer can be positioned outward of the periphery of the perforated region of the first substrate layer and outward of the periphery of the perforated region of the second substrate layer. 
     The foregoing and other features and advantages will become more apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings, wherein like numerals refer to like parts throughout the several views and this specification, aspects of presently disclosed principles are illustrated by way of example, and not by way of limitation. 
         FIG. 1A  illustrates a plan view from above a liquid-resistant microphone assembly. 
         FIG. 1B  illustrates an end-elevation view of the assembly in  FIG. 1A . 
         FIG. 1C  illustrates a side-elevation view of the assembly in  FIG. 1A . 
         FIG. 2A  illustrates a cross-sectional view of the assembly in  FIG. 1A  taken along section line  2 - 2 . 
         FIG. 2B  illustrates a cross-sectional view of a liquid-resistant microphone assembly having a different substrate arrangement compared to the microphone assembly shown in  FIG. 2A . 
         FIG. 2C  illustrates a cross-sectional view of a liquid-resistant microphone assembly having a different substrate arrangement compared to the microphone assemblies shown in  FIGS. 2A and 2B . 
         FIGS. 3A, 3B, and 3C  show additional detail from  FIGS. 2A, 2B, and 2C , respectively. 
         FIG. 4A  illustrates several components and sub-assemblies in an electronic device. 
         FIG. 4B  illustrates several alternative components and sub-assemblies in an electronic device. 
         FIG. 5A  illustrates detail of a sealable coupling between a liquid-resistant microphone assembly shown in  FIGS. 4A and 4B  with an enclosure for an electronic device. 
         FIG. 5B  illustrates detail of an alternatively arranged sealable coupling. 
         FIG. 6  illustrates a cross-sectional view of an alternative arrangement for a liquid-resistant microphone assembly. 
         FIG. 7A  illustrates a cross-sectional view of an alternative arrangement for a liquid-resistant microphone assembly having a MEMs microphone directly mounted to a liquid-resistant membrane. 
         FIG. 7B  illustrates a cross-sectional view of a microphone assembly similar to that in  FIG. 7A  with an added stiffener or other substrate. 
         FIG. 7C  illustrates a cross-sectional view of a microphone assembly similar to that in  FIG. 7B  with an added acoustic or other protective mesh spanning across a sound-entry opening. 
         FIG. 8A  illustrates a plan view of a liquid-resistant microphone assembly arranged as a “bridge” between first and second interconnect substrates. 
         FIG. 8B  illustrates a cross-sectional view of the assembly shown in  FIG. 7A  taken along Section line  8 B- 8 B. 
         FIGS. 9A through 9D  schematically illustrate alternative arrangements for a liquid-resistant microphone assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes various principles related to liquid-resistant packages, e.g., for microphone transducers (or other components), as well as electronic devices and related systems. For example, some disclosed principles pertain to systems, methods, and components that permit passage of acoustic energy with little or no damping while concurrently inhibiting intrusion of a liquid beyond a selected boundary of a component package. To illustrate, liquid-resistant microphone assemblies are described. That said, descriptions herein of specific appliance, apparatus or system configurations, and specific combinations of method acts, are just particular examples of contemplated appliance, apparatus or system configurations, and method combinations, chosen as being convenient to illustrate disclosed principles. One or more of the disclosed principles can be incorporated in various other appliance, apparatus or system configurations, and method combinations, to achieve any of a variety of corresponding, desired characteristics. Thus, a person of ordinary skill in the art, following a review of this disclosure, will appreciate that combinations having attributes that are different from those specific examples discussed herein can embody one or more presently disclosed principles, and can be used in applications not described herein in detail. Such alternative embodiments also fall within the scope of this disclosure. 
     I. Liquid-Resistant Package for Acoustic Transducer 
     Referring now to  FIGS. 1A, 1B, 1C, 2A, 2B, and 2C , liquid-resistant component packages, e.g., for a microphone transducer, are illustrated and described. Each component package  100  has a substrate  102  defining a first major surface  104  and an opposed second major surface  106 . The substrate  102  also defines at least one aperture  101   a  extending through the substrate from the first major surface  104  to the second major surface  106 , defining a sound-entry opening  101  through the substrate  102 . A microphone transducer  105  is mountably coupled with the substrate  102  on the first major surface  104  and has a sound-responsive diaphragm (not shown) acoustically coupled with the sound-entry opening  101  defined by the substrate, permitting sound to enter a front volume of the microphone transducer. A lid  107  overlies the microphone transducer  105  and is mounted to the substrate  102 . 
     Opposite the microphone transducer  105  relative to the substrate  102 , a liquid-resistant port membrane  108  is mountably coupled with the second major surface  106  ( FIG. 3A ) of the substrate  102 . The port membrane  108  spans across the sound-entry opening  101  defined by the substrate  102 . The membrane  108  is spaced apart from the second major surface  106  of the substrate  102 , defining a gap Gi positioned between the membrane  108  and the second major surface  106  of the substrate. The port membrane  108  can be sufficiently gas permeable to permit acoustic energy to pass therethrough and yet inhibit passage of liquids therethrough, defining a gas-permeable, liquid-resistant region of the package  100 . In another embodiment, the port membrane is gas- and liquid-impermeable under operating conditions for which the component package  100  is intended. 
     For example, the port membrane  108  can be sufficiently gas permeable as to be “acoustically transparent,” e.g., by transmitting acoustic pressure waves across the port membrane with limited damping. As used herein, “acoustically transparent” means having an acoustic impedance less than about 45 MKS Rayls, such as, for example, between about 25 MKS Rayls and about 35 MKS Rayls. As well, some membranes prevent movement of water across the port membrane  108  when a hydrostatic pressure gradient across the port membrane falls below a selected threshold hydrostatic pressure gradient. Nonetheless, a port membrane  108  need not be acoustically transparent, particularly when other competing design priorities are addressed. For example, about 3.5 dB loss in sound power may be acceptable for some embodiments, e.g., embodiments expected to be exposed to relatively high (e.g., between 2 bar and 5 bar) hydrostatic pressure gradients. 
     In general, a suitable port membrane for a particular application can permit a flow of gas therethrough while being impermeable to a liquid at liquid breakthrough pressures below a selected threshold pressure. For example, pores in the port membrane  108  can measure between about 0.1 μm and about 10 μm, making the port membrane gas permeable while inhibiting liquid movement across the membrane. The membrane can have a thickness, t, measuring between about 5 μm and about 50 μm, e.g., between about 10 μm and about 30 μm, 
     A representative example of a permeable port membrane  108  can be formed of PTFE or ePTFE, though other suitable materials can be used in place of or in addition to PTFE or ePTFE. Such materials include, for example, polymerized fibers (e.g., polyvinylidene fluoride, or polyvinylidene difluoride, both of which generally are referred to in the art as “PVDF” and are inert thermoplastic fluoropolymers produced by the polymerization of vinylidene difluoride). 
     As used herein, the term “PTFE” means polytetrafluoroethylene. PTFE, commonly referred to by the DuPont trademark Teflon® or the ICI trademark Fluon®, is well known for its chemical resistance, thermal stability, and hydrophobicity. Expanded PTFE, sometimes also referred to as ePTFE, has a porous structure defined by a web of interconnected fibrils. ePTFE commonly has a porosity of about 85% by volume, but because of its hydrophobicity, has a relatively high liquid breakthrough pressure (i.e., a threshold hydrostatic pressure below which the ePTFE remains impermeable to the liquid) for a variety of liquids, including water. 
     Other port-membrane embodiments can have a composite or a laminate construction. For example, plural layers of material can be laminated together. In one example, a woven or knit material can be laminated to ePTFE or PTFE to add tensile and/or shear strength to the membrane. In other embodiments, a composite port membrane can be formed by forming ePTFE (or other material) around a lattice structure (e.g., a knit or woven sheet material, like a fabric or screen, formed of any of a variety of materials). In some port-membrane embodiments, a coating or a treatment can be applied to enhance oleophobicity of the membrane. 
     Still other port-membrane embodiments may be impermeable to a gas, e.g., air or components thereof (e.g., nitrogen, oxygen). For example, a port membrane may have a non-porous structure or a porous structure in which the pores are smaller than selected gas molecules, preventing passage of the gas through the structure. With a gas-impermeable membrane, acoustic pressure variations (sometimes also referred to as sound waves) can be transferred across the membrane by inducing mechanical vibrations in the membrane from incident acoustic energy on a first membrane side. As the membrane vibrates, the vibrations can induce corresponding pressure variations on a second membrane side positioned opposite the first side. When using a non-porous or other gas-impermeable membrane, barometric venting of the component  100  may differ from venting used in connection with a porous or gas-permeable membrane. For example, a lateral vent can be provided within the substrate  140   a ,  140   b ,  140   c  extending from a region adjoining the side of the membrane  108  facing the microphone transducer  105  laterally outward of the lid  107 . In an embodiment, the adhesive layer  110  can define a laterally extending channel (e.g., not shown but extending parallel to the cross-section in  FIGS. 3A, 3B, 3C ). In another embodiment, the substrate  102  can define such a channel or other vent passage to a region enclosed by the lid  107  or to a region external of the lid  107 . 
     As  FIGS. 2A and 3A  illustrate by way of example, a peripheral region of the port membrane  108  can be adhesively secured to the second major surface  106  of the substrate  102  at a position outward of the sound-entry opening  101  of the substrate  102 . 
     The region of attachment between the port membrane  108  and the substrate  102  can define a liquid-impermeable or at least a liquid-resistant adhesive bond. Thus, independently attaching the port membrane  108  to the substrate  102  can permit hydraulic leak testing of the substrate-and-membrane assembly prior to assembling the microphone transducer  105  to the substrate  102 . A suitable adhesive bond can be formed using a temperature-sensitive adhesive tape  110  formed with an acrylic adhesive on opposed major surfaces of a polyester or a polyimide carrier. In one example, the adhesive tape can measure about 50 μm thick, e.g., between about 40 μm and about 60 μm, for example, between about 30 μm and about 70 μm. 
     A thickness of the adhesive tape  110  can be selected to space the port membrane  108  from a surface  106  of the substrate  102 . A separation gap Gi ( FIG. 3A ) can reduce a likelihood that the port membrane  108  may impact or otherwise contact the substrate  102 , e.g., near the sound-entry opening  101 , when exposed to a threshold level of acoustic energy across a selected frequency band. For example, the port membrane  108  may tend to resonate when exposed to a selected frequency of acoustic energy, yet selecting an adhesive of a thickness greater than a likely amplitude of the membrane&#39;s vibration can prevent the port membrane  108  from contacting the substrate  102 . Eliminating or preventing such a vibratory contact between the membrane  108  and the substrate  102  may be desirable, as such vibratory contact may impair an acoustic signal passing into the package  100 . 
     Nonetheless, when exposed to hydraulic pressure, the membrane  108  can deform and be supported by the substrate  102 . According to one aspect, the gap Gi is sized to maintain deformation of the membrane  108  to be elastic and to prevent plastic deformation of the membrane as the membrane deforms and contacts the substrate under a hydraulic pressure. 
     Under sufficient deformations of the port membrane  108 , the port membrane can come into contact with and urge against the sound-entry region  101  of the substrate  102 . A gap distance Gi between the substrate  102  and the port membrane  108  can be selected to ensure the material of the port membrane  108  remains within an elastic-deformation regime over a range of potential deformations (e.g., until the membrane  108  urges against and is supported by the second major surface of the substrate  102 ). Larger gap distances may allow a plastic deformation of the port membrane, permanently deforming the membrane and degrading acoustic performance, gas-permeability, or both. Despite advantages just described, the port membrane  108  can alternatively be attached to and supported by the first major surface  104  of the substrate  102 , e.g., between the microphone transducer  105  and the first major surface of the substrate. 
     The adhesive tape  110  can define an aperture  111  sized and shaped in correspondence with a size and a shape of the sound-entry opening  101 . For example, the aperture  111  through the adhesive tape  110  can be the same size and shape as the sound-entry opening (e.g., as in  FIG. 3B ), or the aperture  111  through the adhesive tape can be larger or shaped differently than the region of the substrate defining the sound-entry opening  101  (as in  FIG. 3A ). 
     In an embodiment, a package  100  as just described can be mounted on or otherwise be operatively coupled with another substrate, e.g., a further package-level substrate and/or an interconnect substrate. In the embodiments illustrated in  FIGS. 2A and 2B , an optional, second package-level substrate  120  is positioned opposite the substrate  102  relative to the port membrane  108 . In  FIGS. 2A, 2B, 3A, and 3B , a second adhesive layer  122  is positioned between the port membrane  108  and the second substrate  120 , securing the second substrate in a laminated arrangement with the first substrate  102  and the port membrane  108 . 
     In  FIGS. 2A and 2B , the second substrate  120  defines a sound entry opening  121  acoustically coupled with the sound-entry opening  101  defined by the first substrate  102 , acoustically coupling the second sound-entry opening  121  with the sensitive region of the microphone transducer  105 . The second sound-entry opening  121  through the second substrate  121  can be the same size and shape as the first sound-entry opening  101  (as in  FIG. 2B ), or the second sound-entry opening  121  through the second substrate  120  can be larger or otherwise shaped differently than the region of the substrate  102  defining the first sound-entry opening  101  (as in  FIG. 2A ). Similarly, the second sound-entry opening  121  through the second substrate  120  can be the same size and shape as each respective aperture  111 ,  123  through the adhesive tape layers  110 ,  122 , respectively, or the second sound-entry opening  121  can be larger or shaped differently than the apertures through the layers of adhesive tape. In still another embodiment, the relative sizes and shapes of the sound-entry openings  101 ,  121  and apertures  111 ,  123  through the adhesive layers  110 ,  122 , respectively, can be selected in any desired combination to tune the acoustic response of the liquid-resistant microphone assembly  100  at the microphone transducer  105 . 
     As an example, each of the first sound-entry opening  101  and the second sound-entry opening  121  has a corresponding characteristic dimension. Flow or acoustic characteristics of an aperture may vary with a selected characteristic dimension of the aperture. In some instances, a characteristic dimension of a given structure can be defined in a manner to enable, e.g., acoustic or flow comparisons of structures having different shapes. For example, a characteristic dimension of a circle can be a diameter of the circle. On the other hand, a characteristic dimension of a square can be length of the side of the square, or a ratio of an area of the square to a perimeter of the square. Such a ratio is sometimes referred to in the art as a hydraulic diameter. For a circle, the ratio reduces to the diameter of the circle. 
     A substrate  140   a ,  140   b ,  140   c , as viewed in  FIG. 1A , can measure about 4.000 mm by about 3.500 mm. For example, in selected embodiments, each ordinate dimension can measure between about 2.500 mm and about 6.000 mm, such as, for example, between about 3.000 mm and about 5.000, or between about 3.300 mm and about 4.100 mm. Each aperture  101   a  defining a sound-entry opening through the first constituent substrate layer  102  can be a non-plated through via having a diameter measuring between about 50 μm and about 200 μm, such as, for example, between about 75 μm and about 150 μm, e.g., between about 90 μm and about 110 μm. The sound-entry region  150  can have a characteristic dimension, e.g., a diameter in selected embodiments, measuring between about 1.000 mm and about 3.000 mm, such as, for example, between about 1.200 mm and about 2.400 mm, e.g., between about 1.4 mm and about 2.2 mm. 
     As shown in  FIG. 2A , the second sound-entry opening  121  can be larger than the sound-entry opening  101  defined by the first substrate  102 . As well, the periphery of each adhesive layer  110 ,  122  is recessed from the periphery  121  of the second sound-entry opening. In a working embodiment, the relative sizes of the openings schematically illustrated in  FIG. 2A  were determined to provide improved acoustic response to an intended audio source at the microphone transducer  105  compared to an embodiment in which a periphery of the aperture through the layers of tape coincided with a periphery of the second sound-entry opening (as in  FIG. 2B ). 
     As  FIGS. 2A and 3A  show, an acoustic mesh  130  can be attached to a second major surface  124  of the second substrate  120 , spanning across the second sound-entry opening  121 . Such an acoustic mesh can provide a measure of acoustic damping at selected frequencies, further tuning the acoustic response of the liquid-resistant microphone assembly  100 . As well, such an acoustic mesh can inhibit intrusion of debris into the sound-entry opening  150 , which can damage the port membrane  108  or degrade acoustic performance of the package. In an embodiment, the acoustic mesh  130  can be formed from a woven-wire cloth. For example, stainless-steel filaments can be woven to define the mesh. As well, the filaments can be coated, e.g., with a hydrophobic or an oleophobic coating to further inhibit intrusion of debris or liquids. 
     As  FIGS. 2C and 3C  show, the second substrate  120  can be omitted. Even when the second substrate  120  is omitted, the acoustic mesh  130  can be retained. For instance, the mesh  130  can be attached to the port membrane  108  opposite the first substrate  102 . As with the arrangement of the port membrane  108  relative to the substrate  102 , the mesh  130  can be spaced from the port membrane  108  by a thickness of an adhesive layer  131 . 
     II. Liquid Resistant Microphone Modules 
     Referring now to  FIG. 4A , a liquid-resistant microphone assembly  100  of the type described herein can be incorporated in a microphone module  250 . For instance, the microphone module  250  can include a microphone transducer  105  ( FIG. 2A ) having a sound-responsive sensitive region. The microphone transducer  105  can be packaged in a liquid-resistant package acoustically coupled with an external ambient environment through a liquid-resistant sound entry opening  150 . The microphone package  105  may include, for example, a micro-electro-mechanical system (MEMS) microphone. It is contemplated, however, that microphone transducer can be any type of electro-acoustic transducer operable to convert sound into an electrical output signal, such as, for example, a piezoelectric microphone, a dynamic microphone or an electret microphone. 
     A microphone module  250  can include an interconnect substrate  200 . As shown in  FIGS. 4A and 4B , the liquid-resistant package  100   a ,  100   b  can be electrically coupled with a complementarily arranged interconnect substrate  200   a ,  200   b . In general, an interconnect substrate  200   a ,  200   b  can include a plurality of electrical conductors configured to convey an electrical signal, or a power or a ground signal, from one interconnection location (e.g., a solder pad)  205   a ,  205   b  to another interconnection location (e.g., another solder pad). For example, a packaged component, e.g., the liquid-resistant microphone assembly  100   a ,  100   b , can be soldered or otherwise electrically coupled with one or more interconnection locations defined by an interconnect substrate. 
     The interconnect substrate can electrically couple the packaged component with one or more other components (e.g., a memory device, a processing unit, a power supply) physically separate from the packaged component. In addition to the microphone transducer, one or more other components can be operatively coupled with the interconnect substrate  200   a ,  200   b . For example, the interconnect substrate can have a region  210  extending away from the microphone package in one or more directions. Within that region  210 , the electrical conductors to which the microphone package is electrically coupled can also extend away from the microphone package. Another component (not shown) can electrically couple with the electrical conductors, electrically coupling the microphone package with such other component. Examples of the other component can include a processing unit, a sensor of various types, and/or other functional and/or computational units of a computing environment or other electronic device. 
     In an embodiment, the interconnect substrate  200   a ,  200   b  can be a laminated substrate having one or more layers of electrical conductors juxtaposed with alternating layers of dielectric or electrically insulative material, e.g., FR4 or a polyimide substrate. Some interconnect substrates are flexible, e.g., pliable or bendable within certain limits without damage to the electrical conductors or delamination of the juxtaposed layers. The electrical conductors of a flexible circuit board may be formed of an alloy of copper, and the intervening layers separating conductive layers may be formed, for example, from polyimide or another suitable material. Such a flexible circuit board is sometimes referred to in the art as “flex circuit” or “flex.” As well, the flex can be perforated or otherwise define one or more through-hole apertures. 
     As shown in  FIGS. 4A and 4B , the microphone package  100   a ,  100   b  defines a plurality of exposed electrical contacts  117   a ,  117   b  configured to be soldered or otherwise electrically connected with a corresponding interconnection location  205   a ,  205   b  defined by the respective interconnect substrate  200   a ,  200   b . In an embodiment, the electrical contacts  117   a ,  117   b  are exposed on a same side of the transducer package  100   a ,  100   b  as the sound-entry opening  150 . In such an embodiment, the interconnect substrate  200   a ,  200   b  defines an aperture or other gas-permeable region (not shown) configured to permit an acoustic signal to pass therethrough in an acoustically transparent manner, or with a selected measure of damping, acoustically coupling an ambient environment with the sensitive region of the microphone transducer  105  through the interconnect substrate. 
     Referring now to  FIG. 4A , the interconnect substrate  200   a  can define a first major surface  214 , an opposed second major surface  217 , and an aperture  206  extending through the interconnect substrate from the first major surface to the second major surface. In this embodiment, the package substrate  141   a  defines a plurality of electrical contacts  117   a  on a same side of the transducer substrate  141   a  as the lid  107 . Stated differently, the electrical contacts  117   a  are positioned on a side of the transducer package  100   a  opposite the sound-entry opening  150 . The microphone package  100   a  can be “inverted” and mounted to the second major surface  217  of the interconnect substrate  200   a  with the lid  107  of the package  100   a  extending through the aperture  206  in the electrical substrate. In the arrangement shown in  FIG. 4A , the interconnect substrate  200   a  is spaced apart from the sound-entry opening  150  to the sensitive region of the microphone. As described more fully below, an arrangement having the interconnect substrate  200   a  overlie the package substrate  141   a  as just described can permit the sound-entry opening  150  of the microphone package  100   a  to be placed adjacent a port in an electronic device without sacrificing acoustic responsiveness of the microphone package. 
     In an embodiment as shown in  FIG. 4B , the microphone package  100   b  has a plurality of electrical contacts  117   b  positioned adjacent a peripheral region of the package substrate  141   b  laterally outward of the lid  107 . In  FIG. 4B , the interconnect substrate  200   b  is electrically coupled with the electrical contacts  117   b  and is offset from a centerline of the microphone package  100   b . Stated differently, the microphone package  100   b  extends past an edge  215  of the interconnect substrate (or vice-versa), as in a cantilevered relationship relative to the interconnect substrate. In an embodiment arranged as in  FIG. 4B , the interconnect substrate  200   b  need not define an aperture through which the lid  107  of the package extends, as in the embodiment in  FIG. 4A . That being said, the edge  215  of the interconnect substrate can define a laterally recessed region (not shown) and at recessed region can extend partially around the lid  107  or another vertically displaced component of the microphone package  100   b.    
     In  FIG. 4B , the electrical contacts as positioned adjacent one edge of the substrate  141   b . In  FIG. 4A , the electrical contacts are positioned adjacent a first edge of the substrate  141   a  and adjacent an opposed second edge of the substrate. With a package arrangement as in  FIG. 4A , the package can be “inverted” with the lid  107  surrounded by the interconnect substrate. 
     A stiffener or other supporting member can be coupled with the interconnect substrate  200   a ,  200   b , as to stiffen a region of the interconnection between the interconnect substrate and the microphone package  100   a ,  100   b . For example, such a stiffener  210  ( FIGS. 5A and 5B ) can be adhesively laminated with the interconnect substrate  200   a ,  200   b  so as to stiffen the interconnect substrate in a region opposite the package substrate  141   a ,  141   b  and around the periphery of the lid  107 . Such stiffening may be desirable to maintain or improve a long-term reliability of an electrical interconnection between the microphone transducer and electrical conductors in the interconnect substrate. 
     III. Liquid-Resistant Electronic Devices 
     An electronic device (e.g., a media appliance, a wearable electronic device, a laptop computer, a tablet computer, etc.) can incorporate a liquid-resistant microphone assembly  100  or a liquid-resistant microphone module  250  described herein. For example, referring to  FIGS. 5A, 5B , an electronic device  300   a ,  300   b  can have a chassis having a chassis wall  301 . The chassis wall  301  can define an aperture, e.g., a port  302 , extending through the wall. 
     A sealable coupling between the liquid-resistant microphone assembly  100  and the chassis wall can be direct, as in  FIG. 5A , or indirect as in  FIG. 5B . A liquid-resistant microphone assembly  100  can define a region configured to sealably couple with a corresponding region of the chassis wall  301 . In an embodiment, an interior surface  303  of the chassis wall  301  can define a gasket seat  315  ( FIG. 5A ) extending around an outer perimeter of an acoustic port  302  defined by the chassis wall. In another embodiment, an internal surface of the port  302  can define a gasket seat ( FIG. 5B ). In either arrangement, the liquid-resistant microphone assembly  100  can, directly or indirectly, sealably couple with such a gasket seat. 
     A liquid in which the electronic device is immersed may enter the port  302  in the chassis wall  301 . However, the sealable coupling between the liquid-resistant microphone assembly  100  and the chassis wall  301  can inhibit intrusion of a surrounding liquid into an interior region  310  of the electronic device. As well, the liquid-resistant port membrane  108  can inhibit liquid from penetrating through the sound-entry opening  150  in the package substrate  140 . Accordingly, an assembly as described above can inhibit entry of liquid to regions of the electronic device that may be susceptible to damage from liquid intrusion. 
     A sealable coupling between the liquid-resistant microphone assembly  100  can be a direct coupling, as in  FIG. 5A . For example, the liquid-resistant microphone assembly  100  can define a region  160  extending outward of an around the sound-entry opening  150 . The enclosure wall  301  can define a region, e.g., a gasket seat, complementarily configured relative to the region  160  extending around the sound-entry opening  150 . A gasket member  306  can be positioned in compression between the liquid-resistant microphone assembly  100  and the region  315  of the housing wall. As an example, the gasket  306  can be a polymerized annulus (e.g., an O-ring) defining an open interior region extending from the port  302  through the housing wall  301  to the sound-entry region of the liquid-resistant microphone assembly  100 . With such an arrangement, sound energy can pass through the port  302  defined by the housing wall and into the sound-entry opening  150 . 
     A sealable coupling between the liquid-resistant microphone assembly  100  can be an indirect coupling, as in  FIG. 5B . A housing  320  defining an acoustic duct or channel  325  can sealably couple with the liquid-resistant microphone assembly  100  laterally outward of the sound-entry opening  150 . The housing  320  can extend transversely from the package substrate. In turn, the housing  320  can sealably couple with a region of the chassis wall  301  adjacent the port  302 , as shown in  FIG. 5B . 
     As in  FIG. 5A , the wall  302  can define a region, e.g., a gasket seat, complementarily configured relative to a region of the housing  320  positioned distally from the package assembly  100 . A gasket member  305  can be positioned in compression between the distal region of the housing  320  and the region of the enclosure wall  301 . As an example, the gasket  305  can be a polymerized annulus (e.g., an O-ring) defining an open interior region extending around the housing  320  and being compressed between the housing  320  and the enclosure wall  301  adjacent or in the port  302 . With such an arrangement, sound energy from the port  302  can pass through the acoustic duct  325  and into the sound-entry opening  150  of the package without obstruction. 
     As depicted in  FIG. 5B , the housing  320  can extend from a first end (e.g., sealably coupled with the liquid-resistant microphone assembly  100 ) to an opposed second end (e.g., sealably coupled with the chassis wall  301 ). The acoustic duct  325  extends between the first end of the housing  320  and the second end of the housing. The housing  320  can be liquid-impermeable, e.g., formed from injection-molded plastic. 
     A terminal surface of the housing  320  corresponding to the first end of the housing can define a flange or other abutment, and the package substrate  140  can be adhesively coupled with the abutment. For example, a heat-activated film (HAF) or another adhesive can be positioned between the package substrate  140   a ,  140   b ,  140   c  and the abutment, and the HAF can affix the package substrate to the abutment. 
     As shown in  FIG. 5B , the duct housing  320  can define an interior surface  321  facing the acoustic channel  325  and an exterior surface  322  in opposed relationship to the interior surface. The exterior surface  322  can define a recess extending around the outer periphery (e.g., circumferentially around) of the duct housing  325 . For example, the recess can extend around the exterior surface at a position adjacent the second end (e.g., adjacent the port  302 ). 
     The recess can define a seat for a gasket  305 , e.g., an O-ring. For example, the cross-sectional view in  FIG. 5B  shows a gasket  305  seated in the recess and positioned in compression between the exterior surface  322  of the housing  320  and a corresponding region of the chassis of an electronic device extending around a periphery of the port  302  through the chassis wall  301 . The acoustic port  302  is aligned with or otherwise acoustically coupled with the acoustic channel  325  through the housing  320 . 
     A protective barrier  310  (e.g., an acoustic mesh) can span across the channel  325  at a position between the port membrane  108  and the second end (e.g., port end) of the housing  320 . The protective barrier can be porous, as to permit gas-movement across the barrier and yet inhibit particulate matter or other debris from intruding into the acoustic channel  325 . In an embodiment, the protective barrier  310  can be a polyester-based acoustic mesh being acoustically transparent or having a selected measure of damping. In another embodiment, the protective barrier can include a wire mesh. In yet another embodiment, the protective barrier can include a gas-permeable, liquid-resistant material. 
     Although not shown, a mounting bracket can secure a liquid-resistant microphone module  300   a ,  300   b  in a liquid-resistant electronic device. For example, a mounting bracket can overlie and retain the microphone assembly in compression between the bracket and the chassis wall  301 , maintaining a sealable coupling, e.g., in compression. 
     As may be needed or appropriate, one or more members in a liquid-resistant microphone module can be electrically grounded with a chassis (e.g., chassis wall  301 ) of the electronic device. For example, an electrically conductive tape or other electrical conductor can be electrically coupled to a grounding region on one or more of the microphone transducer and the interconnect substrate. The electrical conductor can electrically couple the respective grounding region with a grounding region of the chassis, or another selected common ground for the electronic device. 
     IV. Other Exemplary Embodiments 
     The examples described above generally concern liquid-resistant electronic devices, electro-acoustic transducers, and modules, as well as related systems. The previous description is provided to enable a person skilled in the art to make or use the disclosed principles. Embodiments other than those described above in detail are contemplated based on the principles disclosed herein, together with any attendant changes in configurations of the respective apparatus or changes in order of method acts described herein, without departing from the spirit or scope of this disclosure. Various modifications to the examples described herein will be readily apparent to those skilled in the art. 
     For example,  FIGS. 2A, 2B, and 2C  show a microphone package  100  in which the microphone transducer  105  is mounted to the first major surface of a substrate  140   a ,  140   b ,  140   c . In another example, however, the microphone transducer  1005  and/or the ASIC  115  can be positioned within a recessed region of a package substrate. 
       FIG. 6  illustrates another embodiment of a liquid-resistant microphone package  500  having a package substrate  540  and a microphone transducer  505  mountably coupled with the package substrate. In  FIG. 6 , the substrate  540  defines a recess  541  having an outer periphery. The microphone transducer  505  is positioned within the recess. 
     Referring still to  FIG. 6 , the MEMS transducer  505  is held in place along its vertical edges. An arrangement as in  FIG. 6  (and  FIGS. 7A, 7B, and 7C ) can reduce mechanical stress (and mechanical strain) imparted to the microphone transducer and its sensitive region arising from deformations to an interconnect substrate as compared to stress and strain imparted to the transducer through a surface-mounted arrangement as in  FIGS. 2A, 2B, and 2C . Such decoupling can reduce or eliminate mechanically-induced or stress-induced noise into an audio signal by deformation of a sensitive region of the transducer  505 ,  605 . 
     In the example shown in  FIG. 6 , the recess defines an aperture extending from the first major surface  530  to the second major surface  531  of a portion  502  (e.g., a first constituent substrate member) of the laminated substrate  540 . An adhesive material  542  secures the microphone transducer  505  to the substrate portion  502 . More particularly, in  FIG. 6 , the outer peripheral surface  505   a  of the microphone transducer  505  is attached to the outer periphery of the recess  541  defined by the substrate  540  with an adhesive material  542 . For example, an adhesive material  542 , sometimes referred to as “die attach,” can extend around the outer peripheral surface  505   a  of the microphone transducer  505  and adhere to an inner surface of the recess  541  in the substrate. 
     To facilitate alignment of the microphone transducer  505 , the recess  541  from the first major surface  530  need not extend entirely through the substrate  540  or the constituent portion  502  thereof. For example, a thin layer of the substrate can extend inwardly of an outer periphery of the microphone transducer  505 . Such a “lip” or “tab” can support the microphone transducer  505  during assembly and before applying die attach in the gap between the outer periphery of the microphone transducer  505  and the inner surface of the recess  541  in the substrate. 
     As also shown in  FIG. 6 , an integrated circuit (IC), e.g., an application-specific IC (ASIC) can be positioned in the recess  541  at a position adjacent the microphone transducer  505 . As well, an adhesive  543  can span a gap between the microphone transducer  505  and the ASIC  515 , as well as the gap between the ASIC and the surrounding substrate recess  541 . In another embodiment, the ASIC can be mounted, e.g., to the first major surface  530  of the substrate at a position adjacent the recess in the substrate. The ASIC can be electrically coupled with the suspended microphone transducer. 
     A bond wire  506  can electrically couple the microphone transducer  505  with the ASIC. In another embodiment, an electrical coupling (e.g., a solder ball) can extend from an electrode positioned on or adjacent the outer periphery of the microphone transducer  505  and a corresponding electrical contact defined by the substrate. An electrical trace or other electrical coupler can extend from the contact to another region defined by the substrate (e.g., a second electrical contact). The ASIC can be electrically coupled with the other region (e.g., the second electrical contact), electrically coupling the microphone transducer  505  and the ASIC  515  with each other. 
     The package substrate  540  defines a sound-entry region having a corresponding periphery. The package  500  further has a liquid-resistant membrane  508 , and an adhesive layer  510  positioned between the membrane and the package substrate  502 . The adhesive layer  510  defines an aperture having a corresponding periphery larger than the periphery of the sound-entry region defined by the package substrate. The adhesive layer adhesively secures the membrane  508  to the package substrate  502  such that the membrane spans across and is spaced apart from the sound-entry region. The package substrate comprises a plurality of electrical contacts  517 , and each electrical contact can be electrically coupled with a corresponding electrical conductor in an interconnect substrate (not shown in  FIG. 6 ). 
     Turning now to  FIG. 7A , an alternative package arrangement is shown. In  FIG. 7A , the microphone transducer  605  and the ASIC  615  is directly mounted to the liquid-resistant membrane  608 , e.g., eliminating an intervening adhesive layer  510 . That being said, an adhesive or other bonding agent coupling the microphone transducer  605  (and ASIC) to the membrane  608  may be placed between the microphone transducer  605  and the membrane  608 . However, directly coupling the microphone transducer and the membrane together can eliminate, e.g., a carrier substrate (e.g., a polyimide substrate) of a double-sided adhesive as described above (e.g., in relation to  FIG. 2 ) Eliminating the carrier substrate for the adhesive can further reduce a thickness of the package. In the arrangement shown in  FIG. 7A , the sound-entry region  650  corresponds in size and shape to the sensitive region of the microphone transducer  650 . 
       FIG. 7B  shows another alternative package arrangement. In  FIG. 7B , a substrate  620  is adhesively coupled with a package arrangement as in  FIG. 7A , e.g., using an adhesive layer  622 . Other forms of attachment, e.g., solder, between the substrate  620  and the package arrangement as in  FIG. 7A  can be used according to an intended function of the substrate  620 . For example, the substrate  620  can be a further package substrate, e.g., carrying electrical signals associated with the microphone transducer  650  or the ASIC  615 . In an embodiment, the substrate  620  can be an interconnect substrate. In an embodiment, the substrate  620  can be a stiffener substrate. For example, the substrate can enhance or modify a stiffness of the substrate  602 , protecting a mechanical integrity of the bond between the microphone transducer  605  and the substrate  602  formed by the adhesive  643 . 
       FIG. 7C  illustrates yet another alternative package embodiment, similar to the embodiment shown in  FIG. 7B . In  FIG. 7C , a mesh  630  spans across the opening  621  defined by the substrate  620 , overlying the sound entry opening  650 . The mesh  630  can be acoustically transparent or can provide a selected degree of acoustic damping, similar to the mesh shown and described in relation to  FIG. 2C  and  FIG. 5B . The mesh  630  can be positioned within the opening  621 , as illustrated, or can be adhered to the substrate  620 , similarly to the arrangement in  FIG. 2C   
     As depicted in  FIG. 8A , a first interconnect substrate  601  can electrically couple with a first plurality of contacts  117  adjacent the first edge of the substrate  141   a  and a second interconnect substrate  602  can electrically couple with a second plurality of contacts adjacent the opposed second edge of the substrate  141   a . With an arrangement as in  FIG. 8A , the microphone package  100  defines a “bridge” spanning a gap positioned between two interconnect substrates  601 ,  602 . 
     Although electrical contacts for liquid-resistant packages are illustrated as being positioned adjacent a single edge (e.g., in  FIG. 4B ) or an opposed pair of edges (e.g., in  FIG. 4A ), an embodiment can have electrical contacts positioned adjacent, e.g., three or more, edges of the substrate, and an embodiment can have electrical contacts positioned adjacent adjacent edges of the substrate (e.g., rather than adjacent opposed edges of the substrate). 
     Although laminated substrate assemblies  140   a ,  140   b ,  140   c ,  540  are shown and described above in relation to circular and annular structures, the laminated assemblies are not so limited in shape.  FIGS. 9A, 9B, 9C, and 9D  show several plan elevation views of alternative substrate assemblies having differently shaped sound-entry regions. For example, disclosed assemblies can have an elongated or an irregular outer periphery shape, such as, for example, an oblong shape, a rectangular shape, an ovoid shape, etc. Similarly, a cross-sectional shape of disclosed acoustic channels and acoustic ports and other structure, including for example, apertures and sound-entry regions, need not be limited to circular shapes. Rather, any suitable shape (e.g., an elongated or irregular shape) may be used. And, no component of any assembly described herein needs to be axi-symmetric. Rather, such component can have any suitable regular or irregular arrangement. Stated differently, disclosed devices, acoustic ducts, ports, vents and channels need not be coaxially arranged or concentric with the corresponding module through which they extend. Accordingly, disclosed devices, acoustic ducts, ports, vents, and channels can be positioned off-center relative to the module of which they are part. 
     And, a substrate having a gas-permeable and water-resistant region need not have a perforation or other aperture laminated with a port membrane, as generally described above. Rather, a suitable process can be used to distribute, apply, deposit, adhere, or otherwise attach a porous, gas-permeable and liquid-resistant membrane to a gas-permeable region of a substrate. For example, polymerized fibers can be deposited directly to the perforated support structure using an electrospinning process. As but one particular example, electrospinning can deposit PVDF fibers to a skeletal structure. Electrospinning and other deposition processes can eliminate the need for laminated, adhesive bonds as described above, while still providing a cap with a gas-permeable and liquid-resistant ported region. 
     Apertures or perforations (or, more generally, gas-permeable region) extending through each successive layer of material between a sensitive region of a microphone transducer and a port or other sound-entry opening can be successively larger than (or smaller than, or equal in size to) the gas-permeable region through an immediately adjoining layer. Selectively sizing the gas-permeable region through each layer can aid in tuning an acoustic response of the acoustic pathway between, e.g., an external port and a sensitive region of the microphone transducer. 
     Directions and other relative references (e.g., up, down, top, bottom, left, right, rearward, forward, etc.) may be used to facilitate discussion of the drawings and principles herein, but are not intended to be limiting. For example, certain terms may be used such as “up,” “down,”, “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” and the like. Such terms are used, where applicable, to provide some clarity of description when dealing with relative relationships, particularly with respect to the illustrated embodiments. Such terms are not, however, intended to imply absolute relationships, positions, and/or orientations. For example, with respect to an object, an “upper” surface can become a “lower” surface simply by turning the object over. Nevertheless, it is still the same surface and the object remains the same. As used herein, “and/or” means “and” or “or”, as well as “and” and “or.” Moreover, all patent and non-patent literature cited herein is hereby incorporated by reference in its entirety for all purposes. 
     And, those of ordinary skill in the art will appreciate that the exemplary embodiments disclosed herein can be adapted to various configurations and/or uses without departing from the disclosed principles. Applying the principles disclosed herein, it is possible to provide a wide variety of liquid-resistant electronic devices, electro-acoustic transducers, and modules, as well as related systems. For example, the principles described above in connection with any particular example can be combined with the principles described in connection with another example described herein. Thus, all structural and functional equivalents to the features and method acts of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the principles described and the features and acts claimed herein. Accordingly, neither the claims nor this detailed description shall be construed in a limiting sense, and following a review of this disclosure, those of ordinary skill in the art will appreciate the wide variety of liquid-resistant electronic devices, electro-acoustic transducers, and modules, as well as related systems, that can be devised under disclosed and claimed concepts. 
     Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto or otherwise presented throughout prosecution of this or any continuing patent application, applicants wish to note that they do not intend any claimed feature to be construed under or otherwise to invoke the provisions of 35 USC 112(f), unless the phrase “means for” or “step for” is explicitly used in the particular claim. 
     The appended claims are not intended to be limited to the embodiments shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to a feature in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. 
     Thus, in view of the many possible embodiments to which the disclosed principles can be applied, we reserve the right to claim any and all combinations of features and acts described herein, including the right to claim all that comes within the scope and spirit of the foregoing description, as well as the combinations recited, literally and equivalently, in any claims presented anytime throughout prosecution of this application or any application claiming benefit of or priority from this application, and more particularly but not exclusively in the claims appended hereto.

Metadata:
Filing Date: 20180928
Publication Date: 20200310
Grant Date: 20200310
Priority Date: 20180928
Inventors: MINERVINI, ANTHONY D.
Wilkes, Jr., David S.
VITT, Nikolas T.
HRUDEY, PETER C.
DAVE, RUCHIR M.
YOUNES, AMIN M.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R2201/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/086", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81B3/0021", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/086", "inventive": true, "first": true, "tree": "[]"}, {"code": "B81B2201/0257", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2201/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81B7/0006", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B7/0038", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B3/0027", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81B3/0027", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B7/0006", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B2201/0257", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81B3/0021", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/086", "inventive": true, "first": true, "tree": "[]"}, {"code": "B81B7/0038", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81C2203/019", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81C1/00293", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B2207/012", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81B2201/0257", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/02", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 69723472