WO2020159527A1

WO2020159527A1 - Microphone boots for electronic devices

Info

Publication number: WO2020159527A1
Application number: PCT/US2019/016230
Authority: WO
Inventors: Chung Hua KU; Kuan-Ting Wu; Chyun Nan Liu
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2019-02-01
Filing date: 2019-02-01
Publication date: 2020-08-06
Anticipated expiration: 2021-08-01

Abstract

A microphone boot for an electronic device can include an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side. The elastomeric microphone boot body can include an elastomeric material having a Vicat softening temperature of from about 40 C to about 100 C.

Description

MICROPHONE BOOTS FOR ELECTRONIC DEVICES

BACKGROUND

[0001 ] Microphones are used in a variety of electronic devices. Generally, microphones are transducers that convert sound waves into electrical signals. Sound waves produce a series of vibrations that hit a diaphragm inside the microphone. When the diaphragm vibrates, the mechanical vibrations can be converted into electrical signals. A variety of microphones have been developed for use in electronic devices, such as condenser microphones, dynamic microphones, ribbon microphones, piezoelectric microphones, carbon microphones, and MEMS microphones, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 A is a perspective view of an external side of a microphone boot, in accordance with an example of the present disclosure;

[0003] FIG. 1 B is a perspective view of a microphone side of the microphone boot of FIG. 1A;

[0004] FIG. 1 C is a cross-sectional view of the microphone boot of FIG. 1A;

[0005] FIG. 2 depicts an example method of manufacturing a microphone boot for an electronic device, in accordance with the present disclosure;

[0006] FIG. 3A depicts a cross-sectional view of a microphone assembly prior to sealing the microphone boot against the microphone, in accordance with an example of the present disclosure; and

[0007] FIG. 3B depicts a cross-sectional view of a microphone assembly after sealing the microphone boot against the microphone, in accordance with an example of the present disclosure. DETAILED DESCRIPTION

[0008] Microphones can play an important function in a variety of electronic devices. Microphones are transducers that convert sound waves into electrical signals. Sound waves produce a series of vibrations that hit a diaphragm inside the microphone. When the diaphragm vibrates, the mechanical vibrations can be converted into electrical signals. A microphone boot can be sealed against the microphone to isolate air and associated sound waves entering the microphone. Thus, the microphone boot can provide a designated acoustic channel to the microphone. Further, a microphone boot can also provide noise reduction/cancellation from unintended sources. However, poor microphone sealing can cause variation in the sensitivity and frequency response of the microphone, detection of noises from within the electronic device, detection of handling noises, and other issues.

[0009] In accordance with this, the present disclosure describes a microphone boot for an electronic device. The microphone boot can include an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side. The elastomeric microphone boot body can include an elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C. In some examples, the microphone boot body can be thermally modified to reduce a volume of the microphone cavity by about 5% to about 70%. In some additional examples, the acoustic channel can have a diameter of from about 0.4 mm to about 1.5 mm. In some other examples, the elastomeric microphone boot body includes from about 98 wt% to about 100 wt% of the elastomeric material based on a total weight of the elastomeric microphone boot body. In some further examples, the elastomeric material includes polyolefin, cyclic olefin copolymers, polybutadiene ethylene-vinyl acetate, polyurethane, or a combination thereof.

[0010] The present disclosure also describes a method of manufacturing a microphone boot for an electronic device. The method can include shaping an

elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C to form a microphone boot. The microphone boot can include an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side. In some examples, shaping the elastomeric material includes injection molding. In some additional examples, shaping the elastomeric material includes heating the microphone boot to a temperature of from about 40 °C to about 100 °C to decrease a volume of the microphone boot by about 5% to about 70%. In some other examples, the microphone cavity can have an initial volume of from about 0.010 cm³ to about 0.020 cm³, and after heating, the microphone cavity can have a final volume that is from about 5% to about 70% less than the initial volume. In some examples, the method further includes applying a pressure sensitive adhesive coating to the microphone side of the elastomeric microphone boot body at a coating thickness of from about 5 pm to about 30 pm. In some further examples, the pressure sensitive adhesive includes an acrylic adhesive, a natural rubber-based adhesive, a styrene- butadiene rubber-based adhesive, a styrene block copolymer-based adhesive, a silicone-based adhesive, or a combination thereof.

[001 1 ] A microphone assembly for an electronic device can include a substrate, a microphone coupled to the substrate, and a microphone boot about the microphone.

The microphone can include an acoustic aperture. The microphone boot can be about the microphone including at the acoustic aperture. The microphone boot can include an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side. The elastomeric microphone boot body can include an elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C. The elastomeric microphone boot body can be thermally modified to reduce a volume of the microphone cavity about the microphone. In some examples, the acoustic aperture can be positioned at or within the acoustic channel. In some additional examples, the elastomeric microphone boot body further includes a filler in an amount from about 0.01 wt% to about 2 wt%. In some further examples, the microphone assembly further includes a pressure sensitive adhesive positioned between the elastomeric microphone boot body and the microphone, between the elastomeric microphone boot body and the substrate, or both.

[0012] In addition to the examples described above, the microphone boots, methods of manufacturing microphone boots, and microphone assemblies will be described in greater detail below. It is also noted that when discussing the microphone boots, methods of manufacturing microphone boots, and microphone assemblies described herein, these relative discussions can be considered applicable to the other examples, whether or not they are explicitly discussed in the context of that example. Thus, for example, in discussing an elastomeric material related to a microphone boot, such disclosure is also relevant to and directly supported in the context of the methods of manufacturing a microphone boot and the microphone assemblies described herein, and vice versa.

[0013] Turning now to FIGS. 1A-1 C, a microphone boot 100 can include an elastomeric microphone boot body 110 shaped to include a microphone cavity 120 on a microphone side 114 and an acoustic channel 130 extending into the microphone cavity from an external side 116 opposite the microphone side. The elastomeric boot body can be made of or include an elastomeric material.

[0014] Vicat softening temperature can be used to compare the heat- characteristics of different materials and can refer to the softening temperature for materials that may have no definite melting point. To accommodate the defining of such materials, the“Vicat softening temperature” can be defined as the temperature at which a sample is penetrated to a depth of 1 millimeter (mm) by a flat-ended needle with a 1 mm² circular cross-section at a load of 10 newtons (N) using a temperature ramp of 50 Kelvin/hour (K/h). Thus, the Vicat softening temperature is used as a way of evaluating a physical property of an elastomeric material, and should not be confused with the temperatures that can be used to thermally modify the temperature of the elastomeric microphone boot body, which can be thermally modified in shape, e.g., to shrink the material and thus the microphone cavity, at a temperature below, at, or above the Vicat softening temperature, as will be described in greater detail below.

[0015] As described herein, the present microphone boot is designed for use in an electronic device. As such, it can be desirable for the Vicat softening temperature of the elastomeric material to be within a range that will not be damaging to surrounding electrical components (e.g. a microphone, printed circuit board (PCB), or the like). Further, the Vicat softening temperature can be high enough to maintain structural integrity of the microphone boot at normal operating temperatures of the electronic device. As such, the elastomeric materials described herein generally have a Vicat softening temperature of from about 40 °C to about 100 °C. In other examples, the elastomeric material can have a Vicat softening temperature of from about 45 °C to about 90 °C, or from about 50 °C to about 80 °C.

[0016] Thus, elastomeric materials having a Vicat softening temperature within the ranges specified above can generally be employed in the microphone boot body 110. Additionally, the elastomeric material can generally be an acoustically opaque material. A variety of elastomeric materials having a Vicat softening temperature within the specified ranges and that are acoustically opaque can be used. Some non-limiting examples of suitable elastomeric materials can include a linear or cyclic polyolefin, polybutadiene ethylene-vinyl acetate, polyurethane, copolymers thereof, the like, or a combination thereof. In some specific examples, the elastomeric material can include a cyclic polyolefin copolymer. In some other examples, the elastomeric material can include polybutadiene ethylene-vinyl acetate. In still other examples, the elastomeric material can include polyurethane.

[0017] The elastomeric microphone boot body 110 can generally include from about 98 wt% to about 100 wt% elastomeric material based on a total weight of the elastomeric microphone boot body. In some other examples, the elastomeric microphone boot body can include from about 99 wt% to about 100 wt% elastomeric material based on a total weight of the elastomeric microphone boot body. In some specific examples, the elastomeric microphone boot body can include from about 99.2 wt% to about 100 wt%, from about 99.5 wt% to about 100 wt%, from about 99.7 wt% to about 100 wt%, about 99.9 wt% to about 100 wt%, or about 100 wt% elastomeric material based on a total weight of the elastomeric microphone boot body.

[0018] In some examples, the elastomeric microphone boot body 110 can also include a variety of fillers. Non-limiting examples of fillers can include silica (e.g. fumed silica, silica aerogel, etc.), carbon nanotube aerogel, graphene aerogel, the like, or combinations thereof. Generally, the amount of filler present in the microphone boot body can be an amount that does not adversely affect the thermal properties of the elastomeric microphone boot body (e.g. ability to decrease in volume to enclose about a microphone). When present, the filler material can generally be included in the microphone boot body in an amount from about 0.01 wt% to about 2 wt%, from about 0.05 wt% to about 1 wt%, from about 0.1 wt% to about 1 wt%, or from about 0.5 wt% to about 1 wt% based on a total weight of the elastomeric microphone boot body.

[0019] As previously described, the microphone boot body 110 can be shaped to include a microphone cavity 120 on a microphone side 114 of the microphone boot body. The microphone cavity can have a variety of shapes depending on the

microphone (not shown, but shown by example in FIGS. 3A and 3B) to which it is intended to couple. For example, where the microphone has a cylindrical shape, the microphone cavity can also have a corresponding cylindrical shape, or where the microphone has a rectangular cuboid shape, the microphone cavity can also have a corresponding rectangular cuboid shape. The microphone cavity can generally have an initial volume that provides a tolerance or gap between the microphone and the interior walls of the microphone cavity during placement of the microphone boot 100 about a microphone. Again, the initial volume can vary depending on the particular microphone to which the boot is intended to couple. Generally, the microphone cavity can have a volume that provides a tolerance or gap between the microphone and an interior surface of the microphone cavity of from about 0.05 mm to about 0.20 mm, or from about 0.10 mm to about 0.15 mm. In some specific examples, the microphone cavity can have an initial volume of from about 0.010 cm³ to about 0.020 cm³. By having an initial volume that provides a tolerance or gap between the microphone and an interior surface of the microphone cavity, placement of the microphone boot about the microphone can be facilitated. After placement, the microphone boot body can be thermally modified to reduce the initial volume of the microphone cavity by about 5% to about 70%, by about 8% to about 50%, or by about 10% to about 25%.

[0020] The acoustic channel 130 can extend from an external side 116 into the microphone cavity 120. The acoustic channel can generally be positioned to align with the sound port or acoustic aperture of a microphone. It is noted that where the acoustic channel does not properly align with the acoustic aperture of the microphone, the acoustic aperture can be either completely or partially blocked. This can lead to decreased sensitivity and frequency response of the microphone, or, in some cases, muting of the microphone. The acoustic channel can have a variety of geometries, such as circular, ovular, square, rectangular, polygonal, etc. In some specific examples, the acoustic channel can have a circular (or cylindrical) geometry. The diameter“D” of the acoustic channel can also vary, depending on the particular microphone to which the microphone boot 100 is intended to couple. The term“diameter” can refer to circular cross-sectional geometries, but other geometries can likewise be used that are not circular in cross-section. In such instances,“diameter” can be calculated based on the cross-sectional area of the non-circular geometry, and that area can be used to constructively provide a circular shape of the same area, and that circular shape can be used to provide the“diameter.” Generally, the diameter of the acoustic channel can be large enough to not block the acoustic aperture of the microphone. In some specific examples, the acoustic channel can have an initial diameter of from about 0.4 mm to about 1.5 mm. Again, after thermal modification of the microphone boot body 110, the initial diameter of the acoustic channel can be reduced by about 5% to about 70%, by about 8% to about 50%, or by about 10% to about 25%.

[0021 ] In some examples, a ridge 132 can circumscribe the acoustic channel 130 on the external side 116. Depending on how the microphone boot 100 is incorporated into an electronic device, the ridge can perform a variety of functions. In some

examples, the ridge can act as a sealing ring that can be adhered to or compressed against an adjacent surface of an electronic device. In some examples, the ridge can act as a funnel to help direct sound waves to the acoustic channel. The ridge can have a variety of shapes. In some examples, the ridge can have a shape that matches the shape of the acoustic channel (e.g. circular ridge and circular acoustic channel). In other examples, the ridge can have a shape that is distinct from the shape of the acoustic channel (e.g. ovular ridge and circular acoustic channel).

[0022] In some additional examples, the microphone boot body 110 can include an alignment flange 112. An alignment flange can help align the microphone boot 100 with a corresponding microphone. For example, a sound hole or acoustic aperture of a microphone may not be centered on the microphone. In such cases, the acoustic channel 130 of the microphone boot will also be off-center. If the microphone boot is attached to the microphone in the wrong direction, the acoustic aperture of the microphone can be blocked. Therefore, an alignment flange can be desirable in some examples.

[0023] In some additional examples, an adhesive coating 140 can be applied to part or all of the microphone side 114 of the microphone boot body 110. The adhesive coating can be applied by spray coating or other suitable process. The adhesive coating can help adhere the microphone boot body to the microphone, an underlying substrate, or both. However, in some cases, thermal modification of the microphone boot body may provide an adequate friction-fit to the microphone that no adhesive is needed in the microphone cavity. In such examples, the adhesive coating may be applied to the microphone side of the microphone boot body exterior to the microphone cavity to facilitate adhesion to an underlying surface. In other examples, the adhesive coating can be applied within the microphone cavity to adhere the microphone boot body to the microphone after thermal modification. Regardless of the specific location on the microphone side, the adhesive coating can generally have a coating thickness T of from about 5 pm to about 30 pm. In other examples, the adhesive coating can have a coating thickness of from about 8 pm to about 25 pm, or from about 10 pm to about 20 pm.

[0024] Where an adhesive coating 140 is present, a variety of adhesive materials can be employed in the adhesive coating. In some examples, the adhesive material can be a pressure sensitive adhesive. Non-limiting examples of suitable pressure sensitive adhesives can include an acrylic adhesive, a natural rubber-based adhesive, a styrene- butadiene rubber-based adhesive, a styrene block copolymer-based adhesive, a silicone-based adhesive, the like, or a combination thereof. In some examples, the adhesive employed can be an adhesive that adequately flows or shears at the Vicat softening temperature of the elastomeric material to permit the elastomeric boot body 110 to enclose about a microphone when heated without significant restriction from the adhesive coating.

[0025] A microphone boot for an electronic device can be manufactured in a variety of ways. An example method 200 of manufacturing a microphone boot for an electronic device is schematically presented in FIG. 2. The method can include shaping 210 an elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C to form a microphone boot. The microphone boot can include an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side.

[0026] Shaping can include an initial shaping to form the initial microphone boot body for placement about the microphone and a subsequent thermal modification to enclose the positioned microphone boot body about the microphone. The initial shaping of the microphone boot can be performed by injection molding, additive manufacturing, or other suitable process. The initial shaping process can provide the microphone boot body with an initial volume, the microphone cavity with an initial volume, and the acoustic channel with an initial diameter. The microphone boot can then be positioned about a microphone and heated to subsequently thermally modify the microphone boot body to reduce the initial volumes thereof to enclose about the microphone.

[0027] In further detail, when heat is applied to the elastomeric material at a temperature close to, at, or above the Vicat softening temperature, the elastomeric material can decrease in volume or shrink in response to the heating. For example, the microphone boot body formed primarily of the elastomeric material can be thermally modified from an initial volume (as initially shaped) to a thermally modified and reduced volume to enclose about a microphone. In some examples, the thermal modification can reduce volume of the microphone boot body by about 5% to about 70%, by about 8% to about 50%, or by about 10% to about 25%. Similarly, in some examples, thermal modification of the elastomeric microphone boot body can reduce the initial volume of the microphone cavity and the initial diameter of the acoustic channel by about 5% to about 70%, by about 8% to about 50%, or by about 10% to about 25%.

[0028] Thermal modification can be performed at a variety of suitable softening temperatures. In some examples, the microphone boot can be heated to a softening temperature of from about 40 °C to about 100 °C to thermally modify the elastomeric microphone boot body to a reduced size and volume. In other examples, the

microphone boot can be heated to a softening temperature of from about 45 °C to about 90 °C, or from about 50 °C to about 80 °C to thermally modify the elastomeric microphone boot body to a reduced size and volume. Generally, it is sufficient to heat the elastomeric microphone boot body to a softening temperature of from about the Vicat softening temperature to a temperature that is about 10 °C greater than the Vicat softening temperature. However, higher temperatures can also be used. Further, the elastomeric microphone boot body can generally be heated to a target softening temperature for a period of from about 1 second to about 30 seconds. In other examples, the elastomeric microphone boot body can be heated to a target softening temperature for a period of from about 1 second to about 5 seconds, about 5 seconds to about 10 seconds, about 10 seconds to about 15 seconds, or about 15 seconds to about 20 seconds. In some specific examples, the elastomeric microphone boot body can be heated to a target softening temperature for a period of from about 2 seconds to about 5 seconds.

[0029] The thermal modification process is further illustrated in FIGS. 3A-3B prior to sealing or shrinking a microphone cavity 320 of the microphone boot 300 against the microphone 350, as well as after sealing or shrinking the microphone cavity of the microphone boot against the microphone. Thus, a microphone assembly 400A prior to thermally modifying the microphone boot and a microphone assembly 400B after thermally modifying the microphone boot are both shown in FIGS. 3A and 3B, respectively. The microphone, as shown in this example, can be coupled to a substrate 360. The microphone can include a sound port or acoustic aperture 352. With specific reference to FIG. 3A, the microphone boot can have an elastomeric microphone boot body 310 that can be positioned about the microphone. In this particular example, the elastomeric microphone boot body can further include an alignment flange 312 to facilitate alignment of the acoustic channel 330 of the microphone boot with the off- center acoustic aperture of the microphone. Further, in this particular example, the microphone boot includes an adhesive coating 340 along the microphone side, including within the microphone cavity of the elastomeric microphone boot body. The microphone can be positioned within the microphone cavity. It is noted that the initial volume of the elastomeric microphone boot body and associated microphone cavity allows for a tolerance or gap“G” between the microphone and an interior surface of the microphone cavity. This can facilitate initial placement of the microphone boot about the microphone. Once the microphone boot is positioned about the microphone, the microphone boot can be thermally modified to reduce the volume and size of the microphone boot body to enclose about the microphone.

[0030] FIG. 3B illustrates a thermally modified elastomeric microphone boot body 310 enclosed about microphone 350, shown generally at 400B. The thermal

modification of the elastomeric microphone boot body can further compress the adhesive coating 340 against the microphone and the underlying substrate 360. It is further noted that the thermal modification does not cause any misalignment between the acoustic channel 330 and the acoustic aperture 352. Thus, thermal modification of the elastomeric microphone boot body can couple the microphone boot 300 to the microphone, the underlying substrate, or both to prepare a microphone assembly for an electronic device.

[0031 ] When properly sealed against the microphone 350, the microphone boot 300 can facilitate good microphone sensitivity and frequency response. Further, the microphone boot can provide good acoustic opacity for noises from within the electronic device, handling noises, and other undesired noises. For example, when properly sealed about the microphone, the acoustic channel 330 can be blocked to reduce acoustically detectable signal levels (e.g. decibel levels) by about 80% to 100%. This can be a good indication that sound waves are primarily entering the microphone via the acoustic channel, rather than via any leaks around the microphone boot.

[0032] The microphone assembly 400B for an electronic device can generally include any suitable microphone 350 for an electronic device. Non-limiting examples can include condenser microphones, dynamic microphones, ribbon microphones, piezoelectric microphones, carbon microphones, micro-electro-mechanical systems (MEMS) microphones, or the like. The substrate 360 can also include any suitable substrate. Non-limiting examples can include a PCB, flexible printed circuit board (FPC), or the like. Further, the microphone assembly can be incorporated into a variety of electronic devices, including personal computers, laptop computers, tablets, phones, smart speakers, smart TVs or monitors, remote controls, headsets, smart apparel, other smart devices, or the like. [0033] It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise.

[0034] As used herein, the term“about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be“a little above” or“a little below” the endpoint. The degree of flexibility of this term can be dictated by the particular variable and would be within the knowledge of those in the field technology to determine based on experience and the associated description herein.

[0035] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience.

However, these lists should be construed as though individual members of the list are individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

[0036] Concentrations, dimensions, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include the numerical values explicitly recited as the limits of the range, but also all the individual numerical values or sub-ranges encompassed within that range as if individual numerical values and sub-ranges are explicitly recited. For example, a weight ratio range of about 1 wt% to about 20 wt% should be interpreted to include the explicitly recited limits of about 1 wt% and about 20 wt%, and also include individual weights such as 2 wt%, 11 wt%, 14 wt%, and sub-ranges such as 10 wt% to 20 wt%, 5 wt% to 15 wt%, etc.

[0037] The following illustrates an example of the technology of the present disclosure. In this example, an elastomeric microphone boot body was manufactured by injection molding a cyclic polyolefin copolymer (TOPAS® Elastomer E-140,

commercially available from TOPAS® Advanced Polymers) to have the general shape as the elastomeric microphone boot body depicted in FIGS. 1A-1 C. The cyclic polyolefin copolymer had a Vicat softening temperature of about 64 °C. The elastomeric microphone boot body was spray coated with a pressure sensitive adhesive coating on the microphone side and positioned about a MEMS microphone having an off-center acoustic aperture. The elastomeric microphone boot body was heated to a temperature of about 65 °C until the microphone boot body enclosed about the MEMS microphone. The acoustic channel of the microphone boot body properly aligned with the acoustic aperture of the microphone.

[0038] An acoustic test was performed to determine the effectiveness of the microphone boot seal against the MEMS microphone. Specifically, an audible tone was played with and without blocking the acoustic channel of the microphone boot. A minimum of a 5 decibel (dB) change in detected audio signal between the blocked and unblocked states was used as a threshold to determine passing of the sealing test. There was a greater than 5 dB change in detected audio signal between blocked and unblocked states indicating a good seal of the microphone boot about the MEMS microphone.

[0039] It is to be understood that the above general and specific examples are exemplary or illustrative of the application of the principles of the presented microphone boots, associated methods, and microphone boot assemblies. Numerous modifications and alternatives may be devised without departing from the present disclosure. The appended claims are intended to cover such modifications and arrangements. Thus, while the disclosure has been provided with particularity, various modifications, changes, omissions, and substitutions can be made without departing from the spirit of the disclosure.

Claims

CLAIMS What is Claimed Is:

1. A microphone boot for an electronic device comprising an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side, the elastomeric microphone boot body comprising an elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C.

2. The microphone boot of claim 1 , wherein the microphone boot body is thermally modified to reduce a volume of the microphone cavity by about 5% to about 70%.

3. The microphone boot of claim 1 , wherein the acoustic channel has a diameter of from about 0.4 mm to about 1.5 mm

4. The microphone boot of claim 1 , wherein the elastomeric microphone boot body comprises from about 98 wt% to about 100 wt% of the elastomeric material based on a total weight of the elastomeric microphone boot body.

5. The microphone boot of claim 1 , wherein the elastomeric material comprises polyolefin, cyclic olefin copolymers, polybutadiene ethylene-vinyl acetate, polyurethane, or a combination thereof.

6. A method of manufacturing a microphone boot for an electronic device comprising shaping an elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C to form a microphone boot, the microphone boot comprising an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side.

7. The method of claim 6, wherein shaping an elastomeric material includes injection molding.

8. The method of claim 6, wherein shaping an elastomeric material includes heating the microphone boot to a temperature of from about 40 °C to about 100 °C to decrease a volume of the microphone boot by about 5% to about 70%.

9. The method of claim 8, wherein the microphone cavity has an initial volume of from about 0.010 cm³ to about 0.020 cm³, and after heating, the microphone cavity has a final volume that is from about 5% to about 70% less than the initial volume.

10. The method of claim 6, further comprising applying a pressure sensitive adhesive coating to the microphone side of the elastomeric microphone boot body at a coating thickness of from about 5 pm to about 30 pm.

11. The method of claim 10, wherein the pressure sensitive adhesive comprises an acrylic adhesive, a natural rubber-based adhesive, a styrene-butadiene rubber- based adhesive, a styrene block copolymer-based adhesive, a silicone-based adhesive, or a combination thereof.

12. A microphone assembly for an electronic device comprising:

a substrate;

a microphone coupled to the substrate, the microphone having an acoustic aperture; and

a microphone boot about the microphone including at the acoustic aperture, the microphone boot comprising an elastomeric microphone boot body shaped to include a microphone cavity on a microphone side and an acoustic channel extending into the microphone cavity from an external side opposite the microphone side, the elastomeric microphone boot body comprising an elastomeric material having a Vicat softening temperature of from about 40 °C to about 100 °C, wherein the elastomeric microphone boot body is thermally modified to reduce a volume of the microphone cavity about the microphone.

13. The microphone assembly of claim 12, wherein the acoustic aperture is positioned at or within the acoustic channel.

14. The microphone assembly of claim 12, wherein the elastomeric microphone boot body further comprises a filler in an amount from about 0.01 wt% to about 2 wt%.

15. The microphone assembly of claim 12, further comprising a pressure sensitive adhesive positioned between the elastomeric microphone boot body and the microphone, between the elastomeric microphone boot body and the substrate, or both.