Patent Publication Number: US-11659310-B2

Title: Adapters for microphones and combinations thereof

Description:
BACKGROUND 
     1. Field 
     The present disclosure relates generally to microphones and more particularly to adapter housings for microphones and combinations thereof. 
     2. Introduction 
     Consumer electronic devices like mobile phones, personal computers, smart speakers, hearing aids, true wireless stereo (TWS) earphones among other host device applications commonly incorporate one or more small microphones. Advancements in micro and nanofabrication technologies have led to the development of microphones having progressively smaller size and different form-factors. For example, the once predominate use of electret microphones in these and other applications is being supplanted by capacitive microelectromechanical systems (MEMS) microphones for their low cost, small size and high sensitivity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which advantages and features of the disclosure can be obtained, a description of the disclosure is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only example embodiments of the disclosure and are not therefore considered to limit its scope. The drawings may have been simplified for clarity and are not necessarily drawn to scale. 
         FIG.  1    is an example side cross-section view of a microphone according to a possible embodiment; 
         FIG.  2    is an example side cross-section view of a microphone according to a possible embodiment; 
         FIG.  3    is an example illustration of a MEMS motor and a flex according to a possible embodiment; 
         FIG.  4    is an example side view of a microphone according to a possible embodiment; 
         FIG.  5    is an example side cross-section view of a microphone according to a possible embodiment; 
         FIG.  6    is an example side cross-section view of a microphone according to a possible embodiment; 
         FIG.  7    is an example exploded view of a microphone according to a possible embodiment; and 
         FIG.  8    is an example isometric view of a microphone according to a possible embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments can provide a microphone including an adapter housing. The adapter housing can include an opening and an outer acoustic port. The microphone can include an internal microphone assembly disposed at least partially within the adapter housing. The internal microphone assembly can include an internal housing having an internal acoustic port. The internal microphone assembly can include a plurality of contacts disposed on the internal housing. The contacts can be accessible through the opening of the adapter housing. An interior of the internal housing can be acoustically coupled to the outer acoustic port via the internal acoustic port. 
     Referring to different possible embodiments shown in  FIGS.  1 ,  2 , and  4 - 8   , a microphone  100  can include an adapter housing  110  and an internal microphone assembly  120 . The adapter housing  110  can be a can, which can be made of metal, metal-coated plastic, FR4, plastic and/or other materials. The adapter housing  110  can also be a can and a base, can be two cans, and/or can be any other arrangement of housing elements. The base can be a Printed Circuit Board (PCB), a substrate, or any other element that can provide a base. The internal microphone assembly  120  can be a MEMS microphone assembly, an electret microphone assembly, a piezoelectric microphone, among other known and future microphone assemblies. 
     Referring to different possible embodiments shown in  FIGS.  1 ,  2 , and  4 - 7   , the microphone  100  can include an internal housing  130 . Referring to different possible embodiments shown in  FIGS.  1 ,  2 , and  5 - 7   , the microphone  100  can include an outer acoustic port  112 . Referring to different possible embodiments shown in  FIGS.  1 ,  2 ,  5 , and  6   , the adapter housing  110  can include an opening  118 . 
     The internal microphone assembly  120  can be disposed at least partially within the adapter housing  110 . The internal housing  130  can have an internal acoustic port  132 . The internal microphone assembly  120  can also include a plurality of contacts  140  disposed on the internal housing  130 .  FIG.  7    shows individual contacts  140  on the internal microphone assembly  120  wherein the contacts  140  are accessible and exposed through the opening  118  of the adapter housing  110  (without use of PCB  210  shown in  FIG.  1    or the flex shown in  FIG.  2   ). An interior of the internal housing  130  can be acoustically coupled to the outer acoustic port  112  via the internal acoustic port  132 . 
     According to a possible embodiment, the interior of the internal housing  130  can be acoustically coupled to the outer acoustic port  112  via the internal acoustic port  132  and via an acoustic channel  114 , such as an acoustic path, between the internal housing  130  and the adapter housing  110 . The acoustic channel  114  can also be located between the internal housing  130  and the adapter housing  110  on sides not shown, such as by completely surrounding the internal housing  130  aside from support structures between the housings  110  and  130  or by partially surrounding the internal housing  130 . 
     According to a possible embodiment, the internal microphone assembly  120  can include a MEMS motor  122  and an integrated circuit  124  disposed within the internal housing  130 . Alternatively, the motor can be an electret motor, piezoelectric motor or some other known or future transduction element. The integrated circuit  124  can be electrically coupled to the motor and to the contacts  140  of the internal microphone assembly. In audio applications, the motor can also be acoustically coupled to the outer acoustic port  112  via the internal acoustic port  132 . The motor in combination with the integrated circuit  124  disposed in the internal housing  130  constitute the internal microphone assembly  120 . 
     Referring to  FIGS.  1  and  8    according to possible embodiments, the microphone  100  can be in combination with an interface adapter  210  having a plurality of electrical traces (not shown) that interconnect contacts  140  of the internal microphone assembly with corresponding host device interface contacts  212  on the interface adapter  210 . For example, the contacts can be coupled to pads  214  on the interface adapter  210 , which can be electrically connected to the interface contacts  212 , such as by being joined by a layer of solder. The interface adapter  210  can be a PCB or a flex circuit. Referring to  FIGS.  2 ,  3  and  4   , the microphone  100  can be in combination with an interface adapter configured as a flex circuit  160  having electrical traces  161 ,  162 , and  163  interconnecting contacts  140  of the internal microphone assembly  120  (see  FIG.  2   ) and corresponding contacts  141 ,  142 ,  143  on the flex circuit  160 . In  FIGS.  2  and  4   , the flex circuit  160  has a first end portion  122  connected to contacts  140  of the internal microphone assembly, an intermediate portion that wraps around the internal microphone assembly, and a second end portion with host interface contacts (e.g.,  161 ,  162  and  163  in  FIG.  3   ). The adapter interface can also be used to change the arrangement or order of the contacts  140  on the internal microphone assembly as they appear on at the host device interface contacts of the flex or PCB. For example, GRND, PWR, DATA contacts on the internal microphone can be changed to appear as GRND, DATA, PWR on host device interface of the PCB or flex circuit. 
     The internal housing  130  can include a cover  134  mounted on a base  136 . The contacts  140  can be surface-mount contacts disposed on the base  136  and can comprise a negative contact  142  located between an output signal contact  141  and a positive contact  143 . The flex circuit  160  can have a plurality of host interface contacts  161 - 163  each electrically coupled to a corresponding contact of the internal housing  130  by a corresponding electrical trace  164 . The plurality of host interface contacts  161 - 163  of the flex circuit  160  can include a host output signal contact  162  located between a host positive contact  161  and a host negative contact  163 . The flex  160  can wrap around the outer housing  110  to create terminal pads on the outer housing  110 . 
     The inner housing cover  134  can be a metal can, can be a metal coated plastic can, can be plastic, can have side walls and a lid built up from FR4, such as a thin layer of copper foil laminated to one or both sides, and/or can be any other cover. The base  136  can be an insulator with contacts, such as wire bond contacts on the interior side and surface-mount contacts on the exterior side. Components of microphone  100  can be designed to optimized acoustic properties such as acoustic resistance (R), inertance (L), and compliance (C), for filtering frequency response and/or noise. The base  136  can be PCB, such as FR4, can be plastic, can be a substrate, and/or can be any other base. Materials used for the inner housing cover  134 , the base  136 , the adapter housing  110 , and/or other components can be used interchangeably, and/or for other elements. 
     Referring to  FIGS.  1 ,  5 , and  6   , the microphone  100  can include an acoustic channel  114  between the internal housing  130  and the adapter housing  110 . The internal acoustic port  132  can be acoustically coupled to the outer acoustic port  112  by the acoustic channel  114 . The acoustic channel  114  can be a tortuous path or other path or channel. The tortuous path can be an ingress barrier to light or particle contamination. The acoustic channel  114  can be configured to tune acoustic properties of the microphone. The acoustic properties include inertance (L), compliance (C), and/or resistance (R). 
     The acoustic channel  114  can have a defined length in the direction of air flow and a cross-sectional area perpendicular to air flow. The cross-sectional area can be defined by width and height, such as thickness, where the smaller dimension can be the height. 
     Acoustic compliance can be proportional to volume. Acoustic inertance can be proportional to length and inversely proportional to cross sectional area. Acoustic resistance can be proportional to length, inversely proportional to width, and, if sufficiently narrow, inversely proportional to the height to power of three, such as cubed. 
     Increased compliance can increase microphone sensitivity and can reduce resonant frequency. Increased inertance can reduce resonant frequency. Increased resistance can reduce resonant amplitude. Acoustic resistance (R), inertance (L), and compliance (C) can also be combined to resonating or filtering structures analogous to an R L C electrical resonator or an R C low pass filter. 
     The acoustic channel  114  can be and/or can be part of a resonator cavity. For example, the volume of the acoustic channel  114  itself can act as a resonator. According to another possible embodiment, at least one additional path or cavity can further act as a resonator in combination with the acoustic channel  114 . 
     According to a possible embodiment, the microphone  100  can include at least one support member  170  separating at least a portion of the adapter housing  110  from at least a portion of the internal housing  130 . The support member  170  can define at least a portion of the acoustic channel  114 . A structure of the support member  170  can modify an acoustic property of sound propagating through the acoustic channel  114 . For example, the support member  170  can made of ribs, fiber, woven material, gel, bumps, or other structures that can modify an acoustic property of sound propagating through the acoustic channel  114 . 
     Referring to  FIG.  1    according to a possible embodiment, the MEMS motor  122  can separate the internal housing  130  into a back volume  196  and a front volume  194  acoustically coupled to the internal acoustic port  132 . Referring to  FIG.  2    according to a possible embodiment, the internal housing  130  can include a back volume port  198  acoustically coupling the back volume  196  to a space  172  between the adapter housing  110  and the internal housing  130 . The space  172  can be used as an enclosed volume and may not be open to the exterior of the adapter housing  110 . According to another possible embodiment the space  172  can be open to an exterior of the adapter housing  110  via an external acoustic port, similar or dissimilar to the outer acoustic port  112 . According to a possible embodiment, the flex circuit  160  of  FIGS.  3  and  4    can be used as an interface between the contacts  140  and the electrical traces  212 . Alternately, the host interface contacts  161 - 163  can be used as or instead of the electrical traces  212 . 
     Referring to  FIGS.  1  and  5   , according to a possible embodiment, the internal housing  130  can include a cover  134  mounted on a base  136 . The plurality of contacts  140  of the internal housing  130  can be surface-mount contacts disposed on the base  136 . Referring to  FIG.  5   , the adapter housing  110  can include a cover  116  mounted to the base  136  of the internal housing  130 . Thus, the internal housing  130  and adapter housing  110  can share the base  136  as a common base. 
     According to other possible embodiments, adapter housing  110  can include a metal can and plate or two metal cans. The adapter housing  110  can also have a PCB base with its own acoustic channel and outer can and can include a standard bottom port MEMS mounted to second PCB or flex. The adapter housing  110  can further have a PCB base with an acoustic channel and an outer can, such as two cans mounted on to one PCB. The adapter housing  110  can additionally have two PCB bases, where one can include an additional acoustic channel and the other can be located on the opposite side having the outer acoustic port  112 . The adapter housing  110  can further have an over-molded external housing and acoustic channel. 
     According to a possible embodiment, the internal housing  130  can include the cover  134  mounted on the base  136 . The internal acoustic port  132 , the contacts  140 , and the MEMS motor  122  can be disposed on the base  136 . 
     According to a possible embodiment, the microphone  100  can include an acoustic channel  114  between the internal housing  130  and the adapter housing  110 . The opening  118  can be disposed on a first side of the adapter housing  110  and the outer acoustic port  112  can be disposed on a second side of the adapter housing  110 . The second side of the adapter housing  110  can be opposite the first side of the adapter housing  110 . The internal acoustic port  132  can be acoustically coupled to the outer acoustic port  112  by the acoustic channel  114 . 
     Referring to a possible embodiment of  FIG.  7    the adapter housing can comprise a first cover  116  in the form of a stainless-steel cup and a second cover  119  in the form of a stainless-steel lid. The internal housing  130  can be a front cavity wall formed of molded plastic. The outer acoustic port  112  can be on a side of the first cover  116 . 
     Referring to  FIGS.  1  and  7   , the microphone  100  can include an acoustic channel  114  between the internal housing  130  and the adapter housing  110 . The opening  118  can be disposed on a first side of the adapter housing  110  and the outer acoustic port  112  can be disposed on a second side of the adapter housing  110 , as shown in  FIG.  7   . The second side of the adapter housing  110  can be non-parallel to the first side of the adapter housing  110 . For example, the opening  118  can be on the bottom of the adapter housing  110  and the adapter sound port  112  can be on the side of the adapter housing. The internal acoustic port  132  can be acoustically coupled to the outer acoustic port  112  by the acoustic channel  114 . 
     Referring to a possible embodiment of  FIG.  8   , a shim  180  can be placed on bottom or top of the internal housing  130 . The shim  180  can have a narrow channel, such as a slot  186 , cut into material to constrict airflow and also the shim  180  may or may not act as a support structure. A flex  182  can also constrict airflow and serve same function. The flex  182  can have a slot  184  and the shim  180  can have another slot  186 . 
     Referring back to  FIG.  1   , the microphone  100  can include the acoustic channel  114  between the internal housing  130  and the adapter housing  110 . The internal acoustic port  132  can be acoustically coupled to the outer acoustic port  112  by the acoustic channel  114 . The MEMS motor  122  can be a capacitive device comprising a diaphragm  192  separating the internal housing  130  into a front volume  194  having a height dimensions h 1  and a back volume  196  having a height dimension h 2  perpendicular to a surface of the diaphragm  192 . The acoustic channel  114  can have a height dimension h 3 , perpendicular to the surface of the diaphragm  192 , where h 3 &gt;h 1 +h 2 . 
     The microphone is generally sensitive to vibration. Referring to  FIG.  1   , acceleration of the microphone  100  can cause displacement of air in the back volume  196  and air in the front volume  194 . Such air displacement can displace the diaphragm  192  resulting in spurious signals, which may produce audible artifacts. The displacement is greatest when acceleration is in the direction perpendicular to the surface of diaphragm. Generally, the forces acting on the surface of the diaphragm are proportional to the height of the volume of air in front the volume h 1  and back volume h 2 . Forces acting on surface area of the diaphragm  192  can also be quantified as pressure. The acceleration of the outer housing  110  can cause air in the acoustic channel  114  to exert force on the surface of the diaphragm  192 . Furthermore, when acceleration is in the direction perpendicular to the surface of diaphragm  192 , the force acting on the surface of diaphragm  192  can be proportional to the height of the volume of air in channel h 3 . 
     Referring to  FIGS.  1 ,  5 ,  6 ,  7 , and  8   , the outer acoustic port  112  can be disposed facing a direction opposite to internal acoustic port  132  with acoustic channel  114  between the outer acoustic port  112  and the internal acoustic port  132 . For this orientation of the internal acoustic port  132  and the outer acoustic port  112 , the direction of the force acting on diaphragm  192  can be opposite to the direction of the forces produced by the air in the front volume  194 , and air in the back volume  196  and can reduce vibration sensitivity. A reduction of vibration sensitivity by more than 3 dB can be considered useful. Cancellation of vibration in a direction perpendicular to the diaphragm surface can be based on
 
 h 3 =h 1 +h 2+(diaphragm_mass/(diaphragm_area*air_density)).
 
     According to a possible embodiment, the opening  118  can be disposed on a first side of the adapter housing  110  and the outer acoustic port  112  can be disposed on a second side of the adapter housing  110 . The second side of the adapter housing  110  can be opposite the first side of the adapter housing  110 . The height dimension h 3  can extend between the first and second sides of the adapter housing  110 . 
     Generally, adapters, such as the adapter housing  110 , of various embodiments can provide backward compatibility for microphones of any technology (e.g., MEMS, electret, piezo, etc.) having a smaller size or different form-factor than legacy microphones. For example, such an adapter can permit use of a MEMS microphone as a drop-in replacement in applications or sockets for which legacy electret microphones are used. At least some embodiments can also provide for ingress protection, from particles and light, and/or flexibility in tuning frequency response and/or noise. 
     For example, embodiments can provide for an internal cavity created by an inner and an outer housing. The internal cavity can provide an acoustic path for frequency response shaping. Embodiments can also provide for an internal cavity created by an inner and an outer housing as additional back volume for a microphone. Embodiments can further provide for an internal acoustic path with air mass to cancel or reduce vibration response. Embodiments can additionally provide for an internal tortuous path for ingress protection with separation of internal and external acoustic ports. Embodiments can also provide for double housing using an inner and an outer housing to provide barrier to light penetration. 
     Embodiments can provide a microphone assembly including an inner MEMS microphone enclosed in outer housing, which can be a metal can or cup and a PCB or flex for terminal pads. The internal microphone can be a MEMS microphone, an electret microphone, or other microphone. The MEMS microphone can be a bottom port or a top port MEMS microphone. The MEMS microphone can have electronic trimmable filters, can have various sizes to tune resonant frequencies, and may or may not be vented into an enclosed volume in an external housing to increase back volume of MEMS microphone for improved performance. The MEMS microphone can be fully packaged as a PCB and a can or a MEMS and an ASIC die mounted on support structure within external housing. External terminals can be on a flex, on a PCB, or can be other external terminals. The external housing can include a metal can or cup, a cover, such as a cup or plate, and terminal pads. It can also have various sizes. The external housing can be rectangular, cylindrical, or any other shape. External terminals and external port configuration can be modified for requirements of hearing aid design, requirements of smartphone design, requirements of laptop computer design, or requirements of other designs for other devices. 
     According to at least some embodiments, an internal acoustic channel, such as a cavity, can be located between the inner and the outer housing. The channel can be created utilizing spacer shim(s), protrusion(s) on a cup, or other structures for acoustic response shaping and can also provide mechanical support or mechanical isolation for an inner microphone. The internal acoustic channel can be designed to tune resonant frequencies and amplitudes of the microphone and can include additional components or material, such as rubber inserts, woven material, fiber, gel, and/or other components or material to modify air flow. The channel can also include porous acoustic material, such as mesh or foam, compliant material, gel, and/or other material in the channel. The internal acoustic channel can additionally include a path or cavity as a resonator. The resonator can be within space between inner or outer housing or incorporated within flex/PCB for terminals. The internal housing can contain a controlled acoustic leak, such as ports or holes, to utilize space between the inner and the outer housing as additional back volume. Acoustical properties of the channel can include any combination of acoustic resistance, inertance and compliance to create damping or resonating structures or other properties. 
     Additional aspects of a MEMS microphone can be utilized to tune acoustical properties of path including a perforated or notched perimeter on MEMS PCB; a size of an MEMS acoustic port, which can affect higher order resonances; and/or an internal microphone port that can be aligned toward or away from external acoustic port to alter length of acoustic channel or to enable the area between inner and outer housing to act as additional back volume. 
     Embodiments can further minimize vibration. For example, the internal channel created by inner and outer housing with an air mass can balance, such as cancel or reduce, motion of air in the microphone inner housing, including front and back volume, and motion of the diaphragm. The design can be adjusted to include any channels external to the microphone in a housing, such as a hearing aid housing. Vibration can also be minimized using soft mounting and supporting material for the internal microphone for mechanical isolation. 
     Embodiments can further provide ingress protection. For example, an internal acoustic channel can separate the external acoustic port and the internal acoustic port for protection against foreign material, such as by using a tortuous path for ingress protection from materials that can be solid, liquid, or vapor. Also, a membrane or mesh, such as a screen, can be inserted into the channel to provide a barrier for ingress protection. 
     Embodiments can additionally provide for a support structure between the inner and outer housings. The support structure can be a protrusion on cup such as a bump or semi perforation, a component such as a spacer or shim, soft material such as rubber or silicone, or other support structures. The support structure can be a hard material like metal or a soft material, such as rubber or gel. The support structure can function as support only, can function as shock protection, can function as acoustic response shaping, and/or can provide other functions. 
     At least some methods of this disclosure can be implemented on a programmed processor. Also, while this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure. 
     In this document, relational terms such as “first,” “second,” and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The phrase “at least one of,” “at least one selected from the group of,” or “at least one selected from” followed by a list is defined to mean one, some, or all, but not necessarily all of, the elements in the list. The terms “comprises,” “comprising,” “including,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “a,” “an,” or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Also, the term “another” is defined as at least a second or more. The terms “including,” “having,” and the like, as used herein, are defined as “comprising.” Furthermore, the background section is not admitted as prior art, is written as the inventor&#39;s own understanding of the context of some embodiments at the time of filing, and includes the inventor&#39;s own recognition of any problems with existing technologies and/or problems experienced in the inventor&#39;s own work.