PATENT DOCUMENT

Publication Number: US-10805713-B2
Application Number: US-201815924049-A
Country: US
Kind Code: B2

Title: Mass loaded earbud with vent chamber

Abstract:
Intra-concha earphones are disclosed. In an embodiment, an intra-concha earphone includes a housing having a rear space divided into a back volume, a bass duct, and a vent chamber between a driver and a rear wall. The vent chamber may be acoustically coupled with the back volume through both an acoustic port and the bass duct. Furthermore, the vent chamber may be acoustically coupled with a surrounding environment through a vent port, which may be a sole acoustic opening in the rear wall. Thus, sound emitted by the driver may propagate through the acoustic port and the bass duct to meet in the vent chamber before being discharged through the vent port to the surrounding environment. Other embodiments are also described and claimed.

Claims:
What is claimed is: 
     
       1. An intra-concha earphone, comprising:
 a driver configured to convert an electrical audio signal into a sound; 
 a housing having the driver therein, wherein the housing includes a housing wall laterally surrounding the driver, the housing including a sole acoustic port in the housing wall behind the driver, wherein the housing wall contains a rear space between the driver and a rear wall of the housing wall, and wherein the sole acoustic port is an only opening in the rear wall through which the sound leaves the rear space; and 
 a partition in the rear space between the driver and the sole acoustic port, wherein the partition includes a groove traversing a back surface of the partition to define an acoustic channel between the back surface and an inner surface of the rear wall. 
 
     
     
       2. The intra-concha earphone of  claim 1 , wherein the inner surface of the rear wall laterally surrounds a rim of the partition, and wherein the partition divides the rear space into a first volume and a second volume. 
     
     
       3. The intra-concha earphone of  claim 2 , wherein the sole acoustic port is a sole externally visible opening in the rear wall. 
     
     
       4. The intra-concha earphone of  claim 3 , wherein the sole acoustic port is the only opening in the rear wall between the first volume and a surrounding environment. 
     
     
       5. The intra-concha earphone of  claim 4 , wherein the first volume is behind the partition, and wherein the second volume is in front of the partition between the driver and the surface of the partition. 
     
     
       6. The intra-concha earphone of  claim 2 , wherein the partition includes one or more apertures extending between the first volume and the second volume. 
     
     
       7. The intra-concha earphone of  claim 2  further comprising signal processing circuitry in the housing between the driver and the rear wall. 
     
     
       8. The intra-concha earphone of  claim 7  further comprising a microphone in the rear space and electrically coupled to the signal processing circuitry. 
     
     
       9. The intra-concha earphone of  claim 8 , wherein the microphone faces the sole acoustic port. 
     
     
       10. An intra-concha earphone, comprising:
 a driver configured to convert an electrical audio signal into a sound; 
 a housing having the driver therein, the housing including a rear wall containing a rear space behind the driver, wherein the housing includes a sole acoustic port in the rear wall, and wherein the sole acoustic port is an only opening in the rear wall through which the sound leaves the rear space; and 
 a partition in the rear space, wherein the partition extends through the rear space to provide a first volume and a second volume, wherein the partition includes a groove traversing a back surface of the partition to define an acoustic channel between the back surface and an inner surface of the rear wall, and wherein the sole acoustic port is the only opening in the rear wall between the first volume and a surrounding environment. 
 
     
     
       11. The intra-concha earphone of  claim 10 , wherein the sole acoustic port is a sole externally visible opening in the rear wall. 
     
     
       12. The intra-concha earphone of  claim 10 , wherein the first volume is laterally surrounded by the rear wall on a first side of the partition, wherein the second volume is laterally surrounded by the rear wall on a second side of the partition, and wherein the first volume is acoustically coupled to the second volume. 
     
     
       13. The intra-concha earphone of  claim 10 , wherein the partition includes one or more apertures extending between the first volume and the second volume. 
     
     
       14. The intra-concha earphone of  claim 10  further comprising signal processing circuitry in the housing between the driver and the rear wall. 
     
     
       15. The intra-concha earphone of  claim 14  further comprising a microphone in the rear space and electrically coupled to the signal processing circuitry, wherein the microphone faces the sole acoustic port. 
     
     
       16. An intra-concha earphone, comprising:
 a driver configured to convert an electrical audio signal into a sound; 
 a housing having the driver therein, the housing including a rear wall containing a rear space behind the driver, wherein the housing includes a sole acoustic port in the rear wall, and wherein the sole acoustic port is an only opening in the rear wall through which the sound leaves the rear space; 
 a partition in the rear space between the driver and the sole acoustic port, wherein the partition includes a groove traversing a back surface of the partition to define an acoustic channel between the back surface and an inner surface of the rear wall; and 
 a microphone in the rear space, wherein the microphone faces the sole acoustic port. 
 
     
     
       17. The intra-concha earphone of  claim 16 , wherein the partition is between a first volume of the rear space and a second volume of the rear space, and wherein the sole acoustic port is the only opening in the rear wall between the first volume and a surrounding environment. 
     
     
       18. The intra-concha earphone of  claim 17 , wherein the sole acoustic port is a sole externally visible opening in the rear wall. 
     
     
       19. The intra-concha earphone of  claim 17 , wherein the partition includes one or more apertures extending between the first volume and the second volume. 
     
     
       20. The intra-concha earphone of  claim 16  further comprising signal processing circuitry in the housing between the driver and the rear wall, wherein the signal processing circuitry is electrically coupled to the microphone. 
     
     
       21. The intra-concha earphone of  claim 1 , wherein the groove includes one or more of a straight groove or a curvilinear groove. 
     
     
       22. The intra-concha earphone of  claim 10 , wherein the groove includes one or more of a straight groove or a curvilinear groove. 
     
     
       23. The intra-concha earphone of  claim 16 , wherein the groove includes one or more of a straight groove or a curvilinear groove.

Description:
This application is a continuation of U.S. application Ser. No. 15/403,392, filed Jan. 11, 2017, which claims the benefit of U.S. application Ser. No. 14/690,237 filed Apr. 17, 2015, now U.S. Pat. No. 9,578,412, issued Feb. 21, 2017, which claims the benefit of U.S. Provisional Patent Application No. 62/018,435, filed Jun. 27, 2014, and this application hereby incorporates herein by reference those patent applications. 
    
    
     BACKGROUND 
     Field 
     Embodiments related to headphones are disclosed. More particularly, an embodiment related to an intra-concha earphone having a rear space divided into a back volume, a bass duct having an acoustic mass, and a vent chamber, is disclosed. The vent chamber may be acoustically coupled with the back volume and the bass duct and may be ported to a surrounding environment through a single rear port, in an embodiment. 
     Background Information 
     Intra-concha earphones, also known as earbuds, are headphones that are placed in the outer ear. Intra-concha earphones may face an ear canal, but are typically not inserted into the ear canal, during use. Since intra-concha earphones do not generally seal within the ear canal, sound can leak from the earphone and not reach the ear canal. Furthermore, sound from a surrounding environment may travel around the earphone into the ear canal, further degrading acoustic performance. Since sound leakage may depend on the anatomy of the user&#39;s ear, acoustic performance of intra-concha earphones may be inconsistent across all use cases. 
     SUMMARY 
     Embodiments of intra-concha earphones are disclosed. In an embodiment, an intra-concha earphone includes a housing holding a driver that converts an electrical audio signal into a sound. The housing may have a rear wall behind the driver and a rear space may be defined between the driver and the rear wall. A chamber partition may be located in the rear space, and may divide the rear space into several spaces, including a back volume behind the driver, a vent chamber between the chamber partition and the rear wall, and a bass duct. The chamber partition may also define one or more ports or apertures, such as an acoustic port that acoustically couples the back volume with the vent chamber, and a bass aperture from which the bass duct extends at the back volume to a duct port at the vent chamber. The rear wall may include a vent port such that the vent chamber is acoustically coupled with a surrounding environment through the vent port. Furthermore, the vent port may be the only acoustic opening in the rear wall of the housing. Thus, a first portion of a sound emitted by the driver may propagate through the acoustic port and a second portion of the sound may propagate through the bass duct such that the sound portions meet in the vent chamber before exiting the housing through the vent port. 
     The chamber partition may include a front surface facing the driver and a back surface facing the rear wall. The front surface may at least partially define the back chamber and the back surface may at least partially define the vent chamber. Furthermore, a duct contour in the back surface may define the bass duct between the chamber partition and the rear wall. In an embodiment, the duct contour follows a curvilinear path over the back surface between the bass aperture and the bass port. The bass port may be located across the vent chamber from the acoustic port, e.g., the ports may be separated by less than 1 mm such that sound passing through acoustic port and duct port enter vent chamber at approximately the same location. 
     In an embodiment, one or more of the ports or apertures in the earphone are covered by an acoustic material. For example, the acoustic port, the duct port, and/or the vent port may be covered by a mesh material. Each port, covered or uncovered, may exhibit an acoustic impedance based on the port geometry, covering material, etc. In an embodiment, the acoustic port has an acoustic impedance that is higher than the acoustic impedances of both the duct port and the vent port. For example, the acoustic port may have an acoustic impedance that is at least 25 times the acoustic impedance of the vent port. The acoustic impedance of the vent port may be lower than about 10 Rayl so as to not substantially impede sound propagation toward the surrounding environment. However, the vent port, or any other port or aperture, may have a non-zero acoustic impedance, relative to open air, as a result of a protective shroud that covers the port and reduces the likelihood that foreign material will intrude into the earphone from the surrounding environment. 
     In addition to providing an acoustic network within the earphone, the one or more chambers formed by the chamber partition may also hold components used for acoustic control. For example, a microphone may be located in the vent chamber to sense sounds from the surrounding environment. The microphone may therefore provide a signal that can be processed to implement active noise control by the earphone. 
     The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an earphone having multiple acoustic openings in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 2  is a cross-sectional view of an earphone having multiple acoustic openings in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 3  is a schematic view of an earphone having multiple acoustic openings in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 4  is a perspective view of an earphone having a single acoustic opening in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 5  is an exploded view of an earphone having a single acoustic opening in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 6  is a cross-sectional view of an earphone having a single acoustic opening in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 7  is a front perspective view of a chamber partition in accordance with an embodiment of the invention. 
         FIG. 8  is a rear perspective view of a chamber partition in accordance with an embodiment of the invention. 
         FIG. 9  is a schematic view of an earphone having a single acoustic opening in a rear portion of a housing in accordance with an embodiment of the invention. 
         FIG. 10  is a schematic view of an earphone having a single acoustic opening in a rear portion of a housing in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention describe headphones for use in playing externally generated audio signals received from an external audio source. However, while some embodiments are described with specific regard to intra-concha earphones, the embodiments are not so limited, and certain embodiments may also be applicable to other uses. For example, one or more of the embodiments described below may be integrated within other devices or apparatuses that direct sound into the ear, such as intra-canal earphones that typically seal against the ear canal. 
     In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions, and processes, in order to provide a thorough understanding of the embodiments. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the description. Reference throughout this specification to “one embodiment,” “an embodiment”, or the like, means that a particular feature, structure, configuration, or characteristic described is included in at least one embodiment. Thus, the appearance of the phrase “one embodiment,” “an embodiment”, or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     In an aspect, an intra-concha earphone includes a housing having a rear space divided into a back volume, a bass duct, and a vent chamber between a driver and a rear wall. The vent chamber may be acoustically coupled with the back volume through both an acoustic port and the bass duct. Furthermore, the vent chamber may be acoustically coupled with a surrounding environment through a vent port. Sound emitted by the driver may propagate through the acoustic port and the bass duct to meet in the vent chamber before being discharged through the same vent port to the surrounding environment. Because the vent port may be a sole opening in the rear wall, e.g., a single externally visible opening in the rear wall, the likelihood that external materials will intrude into the earphone may be reduced. 
     In an aspect, a chamber partition in the housing may define the back volume, the bass duct, and the vent chamber geometry. Thus, the chamber partition may be sized and configured to control an acoustic mass of the volumes within the earphone. Furthermore, the chamber partition may define the acoustic pathways that acoustically couple the driver with the surrounding environment. The acoustic pathways may include the acoustic port between the back volume and the vent chamber, a bass aperture between the back volume and the bass duct, a bass port between the bass duct and the vent chamber, or the vent port exiting to the surrounding environment. Thus, the chamber partition may be sized and configured to control an acoustic impedance of the respective acoustic pathways. The acoustic impedances of the ports and apertures within earphone may be altered by one or more acoustic materials, such as meshes, covering the ports. Thus, the chamber partition and other acoustic elements of the earphone may be configured to achieve a desired resonance of a driver and to tune a frequency response and bass response of the earphone to a desired level. Because the desired acoustic performance can be achieved with an acoustic network that fits within the rear space of the earphone, bass tubes radiating from the rear space may be eliminated, and the earphone can be packaged compactly. 
     Referring to  FIG. 1 , a perspective view of an earphone having multiple acoustic openings in a rear portion of a housing is shown in accordance with an embodiment of the invention. An earphone  100  may be configured to connect to an electronic device, such as a portable media player or another device capable of playing audio, video, or other media. For example, earphone  100  may include an audio jack or other electrical connector that electrically connects the electronic device with a cable  102 . Accordingly, an externally generated audio signal may be delivered through cable  102  to a driver within a housing  104  of earphone  100 . The driver may convert the electrical audio signal into a sound. In an alternative embodiment, the earphone  100  incorporates a wireless interface to receive the externally generated audio signal via a wireless connection with an external amplifier. 
     Housing  104  may be sized and configured to rest within a concha of an ear without sealing against an ear canal of the ear. Accordingly, housing  104  may include a front wall  106  configured to face the ear canal and a rear wall  108  configured to approximate the contour of the concha such that the earphone  100  resists dislodgment from the ear. When resting within the concha, the driver in the housing  104  may emit sound forward through a front acoustic opening  110  in front wall  106  and into the ear canal. In addition to emitting sound in a forward direction through front acoustic opening  110 , sound generated by the driver may be emitted in a rearward direction through a tuning port  112  and a bass port  114 . 
     Referring to  FIG. 2 , a cross-sectional view of an earphone having multiple acoustic openings in a rear portion of a housing is shown in accordance with an embodiment of the invention. Front wall  106  may be defined as a portion of housing  104  extending forward from a driver  202  and rear wall  108  may be defined as a portion of housing  104  extending behind driver  202 . For example, a transverse plane may pass orthogonal to a central axis of driver  202 , and front wall  106  may be the portion of housing  104  axially in front of the transverse plane while rear wall  108  may be the portion of housing  104  axially behind the traverse plane. A rear chamber  204  may be located within housing  104  between driver  202  and rear wall  108 . Thus, sound emitted from driver  202  in a rearward direction may be directed toward tuning port  112  formed through rear wall  108  at rear chamber  204 , as well as toward an acoustic channel  206  leading from rear chamber  204  into an acoustic duct  208 . Sound directed toward acoustic channel  206  may propagate through acoustic duct  208  to bass port  114 . 
     Referring to  FIG. 3 , a schematic view of an earphone having multiple acoustic openings in a rear portion of a housing is shown in accordance with an embodiment of the invention. Sound emitted by driver  202  into rear chamber  204  may include a first sound portion  302  directed toward tuning port  112  and a second sound portion  304  directed toward acoustic channel  206 . More particularly, first sound portion  302  is output to the surrounding environment through a first location of rear wall  108 , i.e., tuning port  112 , and second sound portion  304  propagates through acoustic duct  208  to be output to the surrounding environment through a second location of rear wall  108 , i.e., bass port  114 . First sound portion  302  and second sound portion  304  do not commingle within earphone  100  after leaving rear chamber  204  or before being discharged from housing  104  into the surrounding environment. Accordingly, rear wall  108  includes at least two externally visible openings corresponding to tuning port  112  and bass port  114 , and therefore, external materials such as dust, debris, and other particles may enter earphone  100  through rear wall  108  at multiple locations. 
     Having described a structure and acoustic function of an earphone  100  having multiple acoustic openings in rear wall  108 , the description below shall focus on embodiments of an earphone  100  having a vent chamber that ports to the surrounding environment through a single acoustic opening in a rear housing wall. It will nonetheless be appreciated that the embodiments of the invention described herein are not mutually exclusive, and thus, features of an earphone  100  having multiple acoustic opening in rear wall  108  may be combined with features of an earphone  100  having a single acoustic opening in a rear housing wall within the scope of the invention. 
     Referring to  FIG. 4 , a perspective view of an earphone having a single acoustic opening in a rear portion of a housing is shown in accordance with an embodiment of the description. Earphone  100  may be configured to receive an externally generated audio signal through cable  102  and convert the electrical audio signal into a sound that is played by a driver  202  within housing  104  through front acoustic opening  110  in front wall  106 . Earphone  100  may have housing  104  that is sized and configured to rest within a concha of an ear. Accordingly, the sound may be played through the front acoustic opening  110  into an ear during use. 
     Similar to the embodiment described above with respect to  FIGS. 1 and 2 , driver  202  may also emit sound in a rearward direction toward rear wall  108 . However, in an embodiment, an acoustic mass of acoustic duct  208  may be integrated within rear wall  108  behind driver  202 , along with rear chamber  204 . More particularly, the sound may be routed through an acoustic network axially behind the driver  202  and within the rear wall  108 . A comparison of the earphone  100  embodiments shown in  FIGS. 1 and 4  indicates that incorporating the acoustic network within the rear wall  108  in this manner may allow for a more compact earphone  100 . 
     Referring now to  FIG. 4 , the sound emitted rearward by driver  202  may be discharged from housing  104  through a vent port  402  in rear wall  108 . More particularly, rear wall  108  may include an externally visible acoustic opening through which sound emitted rearward by driver  202  communicates with the surrounding environment. That is, multiple acoustic channels may be routed to meet within housing  104  such that a plurality of vent ports may be unified to vent from housing  104  at a single visual location. Thus, in an embodiment, vent port  402  provides the sole acoustic opening in rear wall  108 . 
     Referring to  FIG. 5 , an exploded view of an earphone having a single acoustic opening in a rear portion of a housing is shown in accordance with an embodiment of the invention. The various components of earphone  100  may be aligned along an earphone axis  502 . Earphone axis  502  may be defined as the axis passing through a center of driver  202 . That is, an outer edge  504  of driver  202  may be axially aligned with earphone axis  502 . For example, in an embodiment, outer edge  504  is circular and is centered about earphone axis  502 . Furthermore, outer edge  504  may be concentric with a diaphragm  506  of driver  202  such that sound emitted by the diaphragm  506  in a forward or a rearward direction initially propagates along earphone axis  502 . Front wall  106  of housing  104  may be disposed forward of driver  202  along earphone axis  502  and rear wall  108  of housing  104  may be disposed rearward of driver  202  along earphone axis  502 . 
     In an embodiment, one or more components may be located within housing  104  between driver  202  and rear wall  108  to divide a volume of space within housing  104  into multiple chambers or volumes. For example, a chamber partition  508  may be located between driver  202  and rear wall  108 . Chamber partition  508  may have a shape that conforms and/or seals against housing  104  in such a way that several volumes or chambers are defined between the surface of chamber partition  508  and the surface of driver  202  or rear wall  108 . For example, a chamber may be defined between driver  202  and a front surface of chamber partition  508 . A back surface of chamber partition  508  may have a duct contour  510 , e.g., a recessed profile, extending along a path to form a groove or channel along the back surface. The duct contour  510  may mate with an inner surface of rear wall  108  to form an acoustic channel having an acoustic mass of air, e.g., a bass tube. The several volumes may further be placed in fluid communication with each other, i.e., acoustically coupled with one another, through various ports, such as acoustic port  512  or bass aperture  514 . Because several independent volumes may be defined by one or more chamber partition  508 , frequency response and bass response of the acoustic network may be tuned by altering the shape of the partitions. Furthermore, since the individual volumes may be acoustically coupled through one or more port or aperture, the frequency response and bass response of the acoustic network may be altered by controlling acoustic impedance of the ports and apertures. Accordingly, mesh elements may cover the ports to alter their acoustic impedance. For example, an acoustic mesh  516  may cover acoustic port  512  and a vent mesh  518  may cover vent port  402 . The meshes may include edges that mate with corresponding edges of the ports such that cross-sectional areas of the ports are filled to cover the ports. 
     Referring to  FIG. 6 , a cross-sectional view of an earphone having a single acoustic opening in a rear portion of a housing is shown in accordance with an embodiment of the invention. A rear space may include the entire volume between driver  202  and rear wall  108  of earphone  100 . Thus, the rear space may be defined by the space surrounded by the apposing surfaces of driver  202  and rear wall  108 . Housing  104  may support driver  202  around outer edge  504  such that a front face of driver  202  faces front wall  106  and a rear face of driver  202  faces the rear space. Accordingly, rear wall  108  of housing  104  may enclose the rear space behind the driver  202 . Thus, as discussed above, as externally generated audio signals are delivered to driver  202  through cable  102  (which may extend through the rear space to attach to driver  202 ) the electrical signals may be converted by driver  202  to sound that is emitted forward to front acoustic opening  110  and rearward into the rear space. 
     In an embodiment, chamber partition  508  resides in the rear space and includes a shape that divides the rear space into one or more volumes. In an embodiment, chamber partition  508  may be assembled from multiple components and/or there may be multiple chamber partitions  508  that subdivide the rear space, however for ease of understanding, chamber partition  508  is described below as essentially including a single body with surface geometry to create an acoustic network of chambers and ducts within the rear space that are acoustically coupled through one or more ports and/or apertures. 
     Chamber partition  508  may include a front surface  602  facing driver  202 . The front surface  602  may define a back volume  604  behind driver  202  and between driver  202  and chamber partition  508 . Back volume  604  may be a sub-volume of the rear space. Back volume  604  may essentially include a cavity with a volumetric geometry that depends on the surfaces of driver  202 , rear wall  108 , and chamber partition  508 . That is, those surfaces may surround, and therefore define, back volume  604 . For example, chamber partition  508  may have a concave front surface  602  defining a corresponding convex portion of back volume  604 . That is, the spatial envelope of back volume  604  may be the negative space conforming to front surface  602 . The size and shape of back volume  604 , as defined by the surfaces surrounding the volume, can be important to the overall acoustic performance of earphone  100 . More particularly, the back volume  604  cavity may tune a frequency response of earphone  100 . In particular, the size of back volume  604  formed between driver  202 , rear wall  108 , and chamber partition  508  can determine the resonance of earphone  100  within, for example, a frequency range of about 2 kHz to about 3 kHz, i.e., open ear gain. The ear canal typically acts like a resonator and has a particular resonance frequency when open and a different resonance frequency when closed. The acoustic response at the ear drum when the ear canal is open is referred to as the open ear gain. A resonance frequency of about 2 kHz to 3 kHz is typically preferred by users. Back volume  604  may be shaped to tune the resonance of earphone  100  to a frequency within this range. More specifically, when rear wall  108  or chamber partition  508  are shaped to reduce back volume  604 , the open ear gain may increase in frequency. As an example, back volume  604  may be reduced by decreasing the radius of rear wall  108  laterally surrounding back volume  604  about earphone axis  502 . Alternatively, back volume  604  may be reduced by decreasing the distance between chamber partition  508  and driver  202  along earphone axis  502 . Conversely, when rear wall  108  or chamber partition  508  are shaped to increase back volume  604 , the open ear gain may decrease in frequency. As an example, back volume  604  may be increased by increasing the radius of rear wall  108  laterally surrounding back volume  604  about earphone axis  502 . Alternatively, back volume  604  may be increased by increasing the distance between chamber partition  508  and driver  202  along earphone axis  502 . Accordingly, back volume  604  geometry may be adjusted to tune the resonance and acoustic performance of earphone  100 . 
     Chamber partition  508  may further define one or more ports or apertures connecting back volume  604  with one or more additional volumes located behind chamber partition  508  from back volume  604 . The additional volumes may be other sub-volumes of the rear space. The rear space within housing  104  may be subdivided to include a bass duct  606  acoustically coupled with back volume  604  through a bass aperture  514 . In an embodiment, bass aperture  514  may be a hole formed through chamber partition  508  (see  FIG. 5 ). However, bass aperture  514  may also be a port defined between an outer edge of chamber partition  508  and an inner surface of rear wall  108  (similar to acoustic port  512  shown in  FIG. 5 ). Thus, bass aperture  514  may provide a channel connecting back volume  604  with bass duct  606 . 
     Similar to back volume  604 , bass duct  606  may be defined as a volume of space between a back surface  608  of chamber partition  508  and an inner surface of rear wall  108 . Bass duct  606  may be a sub-volume of the rear space. That is, bass duct  606  may essentially include a cavity with a volumetric geometry that depends on the surfaces of rear wall  108  and chamber partition  508  surrounding bass duct  606 . For example, chamber partition  508  may define a duct structure extending away from back volume  604  at bass aperture  514 . In addition to defining a duct, chamber partition  508  may also define a duct port  612  at an end of bass duct  606 . For example, duct port  612  may be defined between back surface  608  and rear wall  108 , which may join to create a port shape. The surfaces defining the cavity of bass duct  606  may be sized and shaped to tune a bass response of driver  202 . Just as chamber partition  508  dimensions can be altered to control back volume  604  geometry and hence earphone  100  resonance, chamber partition  508  dimensions can be altered to control bass duct  606  geometry and hence bass response of earphone  100 . In an embodiment, bass response may be controlled to a frequency of less than 1 kHz by shaping bass duct  606  to contain a volume of air that acts as a corresponding acoustic mass. 
     The rear space within housing  104  may further be subdivided to include a vent chamber  610  between chamber partition  508  and rear wall  108 . That is, vent chamber  610  may essentially include a cavity with a volumetric geometry that depends on the surfaces of chamber partition  508  and rear wall  108 . Vent chamber  610  may be a sub-volume of the rear space. Vent chamber  610  may be acoustically coupled with back volume  604  through both acoustic port  512  and bass duct  606 . More particularly, back volume  604  that tunes the earphone  100  resonance may port into vent chamber  610  through acoustic port  512 , while bass duct  606  that tunes the bass response of earphone  100  may port into vent chamber  610  through duct port  612 . Accordingly, sound transmitted through back volume  604  and bass duct  606  may enter, meet, or mix in vent chamber  610  before venting from housing  104 . 
     Optionally, vent chamber  610  may be axially behind acoustic port  512  in a direction of earphone axis  502 . Similarly, vent chamber  610  may be axially behind driver  202  in the direction of earphone axis  502 . For example, a space behind outer edge  504  may form a spatial envelope of a cylinder in the direction of earphone axis  502 . Vent chamber  610  may be encompassed by the spatial envelope such that the entire chamber volume is directly behind driver  202 . Thus, vent chamber  610  may not add additional lateral dimensions to earphone  100  over the lateral dimension that is already formed by outer edge  504  of driver  202 . 
     Transmission of sound from back volume  604  into vent chamber  610  may depend on the geometry of the various interconnected ports and apertures. For example, acoustic impedance of acoustic port  512  may be varied by changing the size or length of acoustic port  512  between back volume  604  and vent chamber  610 . These dimensions may be varied by adjusting the shapes of chamber partition  508  and rear wall  108  surfaces that define acoustic port  512  to achieve the desired acoustic impedance. In addition to modifying chamber partition  508  and rear wall  108  geometries, acoustic materials may be placed over one or more of the various ports or apertures. 
     In an embodiment, an acoustic mesh  516  is disposed over or within acoustic port  512  to modify the acoustic performance of earphone  100 . For example, acoustic mesh  516  may cover acoustic port  512  to alter acoustic impedance of acoustic port  512 . In an embodiment, acoustic mesh  516  is formed of an acoustic material that is acoustically engineered to provide a defined and intentional acoustic resistance or filtering effect. For example, acoustic mesh  516  may be a mesh or foam material that is manufactured to filter certain sound pressure waves emitted by driver  202  toward acoustic port  512 . Alternatively, acoustic mesh  516  may be acoustically transparent so as to not substantially interfere with sound transmission through acoustic port  512 . In either case, acoustic mesh  516  may provide a protective barrier against the unwanted entry of external materials, such as dust, water, or other particles, into back volume  604  from vent chamber  610 . 
     Optionally, an acoustic material may be located over or within duct port  612  or bass aperture  514  to modify the acoustic performance of earphone  100 , or to protect against the unwanted intrusion of external materials into bass duct  606 . For example, a duct mesh (not shown) may cover duct port  612  to alter acoustic impedance of bass duct  606 . In an embodiment, duct mesh is formed of an acoustic material that is acoustically engineered to provide a defined and intentional acoustic resistance or filtering effect. For example, duct mesh may be a mesh or foam material that is manufactured to filter certain sound pressure waves emitted by driver  202  toward duct port  612  through bass duct  606 . Alternatively, duct mesh may be acoustically transparent so as to not substantially interfere with sound transmission through duct port  612  any more than is already inherent in the duct port  612  geometry. In either case, duct mesh may provide a protective barrier against the unwanted entry of external materials, such as dust, water, or other particles, into bass duct  606  from vent chamber  610 . 
     In an embodiment, vent port  402  may be formed through rear wall  108  between vent chamber  610  and a surrounding environment. The surrounding environment may be the ambient environment or the environment outside of earphone  100 . For example, sound may propagate through vent port  402  from vent chamber  610  to a space within a user&#39;s outer ear or into a room within which the user is listening to the earphone  100 . Accordingly, the vent chamber  610  may be acoustically coupled with the surrounding environment through vent port  402 . As described above, vent port  402  may be the sole acoustic opening in rear wall  108  through which any rearward sound leaving housing  104  passes. Similarly, vent port  402  may form a sole visual opening in rear wall  108 . That is, earphone  100  may include only a single opening in rear wall  108  behind outer edge  504  that is visually discernible to a user. 
     A vent mesh  518  may be disposed over or within vent port  402  to modify the surface area through which sound transmits between vent chamber  610  and the surrounding environment. For example, vent mesh  518  may be an acoustically transparent material, meaning that it does not affect an acoustic performance of earphone  100 . Alternatively, vent mesh  518  may modify the acoustic performance of earphone  100 , by altering acoustic impedance of vent port  402 . For example, the vent mesh  518  material may be acoustically engineered to provide a defined and intentional acoustic resistance or filtering effect, e.g., to filter certain sound pressure waves emitted by driver  202  toward vent port  402  through back volume  604 , bass duct  606 , and vent chamber  610 . In either case, vent mesh  518  may provide a protective barrier against the unwanted entry of external materials, such as dust, water, or other particles, into housing  104  from the surrounding environment. 
     Referring to  FIG. 7 , a front perspective view of a chamber partition is shown in accordance with an embodiment of the invention. As described above, chamber partition  508  may include any geometry that fits within the rear space between driver  202  and rear wall  108 , and which subdivides the rear space into an acoustic network. Accordingly, chamber partition  508  may include front surface  602  facing driver  202  and at least partially defining back volume  604 . As such, front surface  602  may include a concave shape extending from a rim  702  to an apex  704  near earphone axis  502 . For example, front surface  602  may include a conical surface with a base perimeter around rim  702  and a locus at apex  704 . Alternatively, front surface  602  may include a quadric surface, such as a paraboloid surface extending from rim  702  to apex  704 . Rim  702  may seal against an inner surface of rear wall  108 , e.g., by an adhesive bond or a press fit between rim  702  and rear wall  108 . Thus, front surface  602  may define a portion of back volume  604  having a conforming convex surface. Although front surface  602  may have a cone shape, it may similarly be shaped as a semi-spherical surface, a cubical surface, a pyramidal surface, etc. Furthermore, front surface  602  need not be concave, e.g., it may be convex or flat. Thus, front surface  602  may have any shape that defines a back volume  604  that imparts desirable acoustic performance to earphone  100 . 
     One or more port or aperture may be formed through chamber partition  508 , e.g., from front surface  602  to back surface  608 . A port or an aperture may be an acoustically calibrated opening or pathway that enhances an acoustic performance of earphone  100 . Ports or apertures within earphone  100  may be any shape, including tear-shaped, circular, elliptical, semi-circular, polygonal, etc. It will be appreciated that in some embodiments, any opening through chamber partition  508  may have an entrance and exit fully defined within rim  702  of front surface  602 , as shown for bass aperture  514 , or may have an entrance or exit defined by the combination of chamber partition  508  and another surface such as rear wall  108 , as shown for acoustic port  512 . Thus, openings connecting the various chambers and ducts within earphone  100  are not intended to be limited exclusively to the geometries shown in the figures. 
     In an embodiment, acoustic port  512  may be a slot extending from rim  702  along a slot edge  706  to form a saddle-shaped opening in the direction of earphone axis  502 . As mentioned above, rim  702  may seal against an inner surface of rear wall  108  such that an enclosed opening is provided for sound emitted by driver  202  to pass from back volume  604  on a front side of chamber partition  508  to vent chamber  610  on a back side of chamber partition  508 . 
     Chamber partition  508  may also include an aperture formed through a wall of chamber partition  508  from front surface  602  to back surface  608 . For example, bass aperture  514  may include a hole through chamber partition  508  at a location that is spaced apart from acoustic port  512  across back volume  604  and/or along front surface  602 . That is, acoustic port  512  and bass aperture  514  may be separated along chamber partition  508  so as to receive and transmit different portions of sound emitted by driver  202 . Unlike acoustic port  512 , bass aperture  514  may be defined between an aperture edge  708  that is fully within rim  702  of front surface  602 , i.e., bass aperture  514  may be an opening, bore, or hole through chamber partition  508 , rather than an opening defined by the combination of rear wall  108  and slot edge  706 . 
     Duct contour  510  may essentially form a cross-sectional profile of bass duct  606 . That is, duct contour  510  may be a recessed profile in back surface  608 , which extends over a path, such as a straight path or curvilinear path  710 , to form a groove traversing a distance along back surface  608 . Thus, when duct contour  510  is a semi-circular recess in back surface  608 , the groove along back surface  608  may have a semi-cylindrical volume over a straight or curvilinear length. Furthermore, bass duct  606  may be defined between the groove and a mating portion of rear wall  108 . Thus, bass duct  606  may enclose a volume of air, e.g., a semi-cylindrical volume of air, which acts as an acoustic mass. 
     Referring to  FIG. 8 , a rear perspective view of a chamber partition  508  is shown in accordance with an embodiment of the invention. Duct contour  510  may extend along a straight or curved length, e.g., along curvilinear path  710 , between a starting point at bass aperture  514  and an ending point at duct port  612 . More particularly, when back surface  608  mates with an apposing surface, such as rear wall  108 , the acoustic mass of bass duct  606  may become enclosed between rear wall  108  and back surface  608  within housing  104 . Accordingly, bass duct  606  may extend from an entrance at bass aperture  514  to an exit at duct port  612 . 
     Acoustic port  512  through chamber partition and duct port  612  between chamber partition  508  and rear wall  108  may be located at vent chamber  610 , as described above. More particularly, sound may be emitted through both acoustic port  512  and duct port  612  into vent chamber  610  of an assembled earphone  100 . In an embodiment, the sound passing through acoustic port  512  and duct port  612  may enter vent chamber  610  near the same location. For example, slot edge  706  partly defining acoustic port  512  and duct contour  510  partly defining duct port  612  may be separated across vent chamber  610 , or along back surface  608  of chamber partition  508 , by a separation gap  802 . In an embodiment, separation gap  802  is less than the length of bass duct  606 . In an embodiment, separation gap  802  is less than about 10 mm. For example, separation gap  802  may be less than 1 mm, e.g., approximately 0.1 mm. Accordingly, sound emitted by driver  202  into back volume  604  may divide and propagate through both acoustic port  512  and duct port  612  before meeting in vent chamber  610  and exhausting to the surrounding environment through vent port  402 . 
     Referring to  FIG. 9 , a schematic view of an earphone having a single acoustic opening in a rear portion of a housing is shown in accordance with an embodiment of the invention. The schematic view aids in visualizing sound paths through earphone  100 . Earphone  100  may include driver  202  with a front face directed toward front acoustic opening  110  such that sound emitted by driver  202  propagates forward into an ear canal. Driver  202  may also emit sound in a rearward direction toward back volume  604 , and for purposes of illustration, sound may be described as splitting into a first sound portion  902  and a second sound portion  904 . First sound portion  902  may propagate through acoustic port  512  in chamber partition  508  to enter into vent chamber  610 . Second sound portion  904  may propagate through bass aperture  514  in chamber partition  508  and bass duct  606  along back surface  608  before entering vent chamber  610 . Thus, first sound portion  902  and second sound portion  904  may enter, meet, or mix within vent chamber  610  after leaving back volume  604  through respective ports or apertures. More particularly, first sound portion  902  and second sound portion  904  may enter a same vent chamber  610 , before discharging to the surrounding environment. Accordingly, first sound portion  902  and second sound portion  904  may propagate in separate directions from driver  202  and then mix at a same location within vent chamber  610  to combine into an output sound  906  that is vented from earphone  100  through vent port  402 . 
     Referring to  FIG. 10 , a schematic view of an earphone having a single acoustic opening in a rear portion of a housing is shown in accordance with an embodiment of the invention. The schematic view aids in visualizing one manner that first sound portion  902  or second sound portion  904  may follow a tortuous path between back volume  604  and vent chamber  610 . However, sound propagating through earphone  100  may follow a tortuous path along any segment of the acoustic network, e.g., even from vent chamber  610  to the surrounding environment. As described above, first sound portion  902  may be emitted by driver  202  through acoustic port  512  into vent chamber  610 . Similarly, second sound portion  904  may be emitted by driver  202  toward bass aperture  514 . Second sound portion  904  may propagate from bass aperture  514  through bass duct  606  toward duct port  612  to enter vent chamber  610 . In an embodiment, bass duct  606  is defined by duct contour  510  that follows curvilinear path  710  along back surface  608 . For example, curvilinear path  710  may be a tortuous path having a number of bends which may be 90 degrees or more. A tortuous path may also include a single bend or curve that extends over a total path length that is at least three times the linear distance between bass aperture  514  and duct port  612 . For example, bass duct  606  may spiral around earphone axis  502  along back surface  608  from bass aperture  514  to an adjacent duct port  612 . That is, the spiral may be along path  710 . First sound portion  902  and second sound portion  904  may meet within vent chamber  610  and combine into output sound  906  that is subsequently discharged to the surrounding environment through vent port  402 . 
     As described above the acoustic ports, apertures, and ducts may be dimensioned to tune an acoustic performance of earphone  100 . Furthermore, additional components, such as meshes placed over the ports and apertures, may be used to tune acoustic performance. One skilled in the art may introduce additional components to further alter acoustic response, such as by implementing baffles or other acoustic materials along surfaces, or suspended within ducts or chambers, of the acoustic network. Such additional components may further alter sound propagation through earphone  100 . Thus, the ports, apertures, ducts, and chambers within earphone  100  are calibrated in the sense that they have been tested or evaluated, in at least one specimen of a manufactured lot, for compliance with a given specification or design parameter. In other words, the acoustic network of earphone  100  is not made of random openings and grooves, but is intentionally formed to modify the acoustic performance of the earphone  100  in a way that tunes the resonance, frequency response, and bass response of earphone  100 . The acoustic tuning parameters may be tuned through variation of the structures described above. Some of these parameters shall now be addressed, although it is to be understood that the following discussion of particular acoustic characteristics may be altered within the scope of this description and is therefore not intended to be limiting of the invention. 
     In an embodiment, each aperture and port of earphone  100  may include a particular acoustic impedance. Acoustic impedance affects how sound propagates through an acoustic medium, e.g., air, and thus, is useful as a tuning parameter to affect, e.g., tuning of a resonance frequency of earphone  100 . Acoustic impedance may be determined based on a geometry and material of a port or aperture, as well as by a geometry and material of another component occluding a portion of the port of aperture, e.g., acoustic mesh  516  or vent mesh  518 . Accordingly acoustic impedance of an aperture or port may be tuned as desired. 
     In an embodiment, an acoustic impedance of acoustic port  512  and/or acoustic mesh  516  over acoustic port  512  is tuned to be higher than an acoustic impedance of vent port  402  and/or vent mesh  518  over vent port  402 . For example, acoustic port  512  may have a smaller diameter than vent port  402 , or acoustic mesh  516  may have a higher mesh surface area to port cross-sectional area ratio, e.g., a higher packing density, than vent port  402 . Accordingly, sound propagation through back volume  604  may be resisted more than sound propagation through vent port  402 , such that sound entering vent chamber  610  discharges freely into the surrounding environment. In an embodiment, the acoustic impedance of acoustic port  512  and/or acoustic mesh  516  may be at least 25 times more than an acoustic impedance of vent port  402  and/or vent mesh  518 . For example, the acoustic impedance of acoustic port  512  and/or acoustic mesh  516  may be 50 to 100 times the acoustic impedance of vent port  402  and/or vent mesh  518 . 
     The acoustic impedance of other ports and apertures within earphone  100  may be similarly tuned. For example, duct port  612  and or a duct mesh over duct port  612  may also have an acoustic impedance, and in an embodiment, the acoustic impedance of duct port  612  and/or the duct mesh may be tuned to be higher than the acoustic impedance of vent port  402  and/or vent mesh  518 . By contrast, the acoustic impedance of duct port  612  and/or duct mesh may be tuned to be lower than the acoustic impedance of acoustic port  512  and/or acoustic mesh  516 . 
     Each chamber or volume within earphone  100  may also include an acoustic impedance. For example, bass duct  606  may have an acoustic impedance that is based on an acoustic mass of the bass duct  606  as well as acoustic losses, e.g., viscous and thermal losses, which occur when sound passes through bass duct  606 . As described above, bass duct  606  may encompass a volume of air that acts as the acoustic mass. The acoustic mass may be conceptualized as mass that is added to diaphragm  506  of driver  202 . Thus, the acoustic mass may be sized, based on the geometry of bass duct  606 , to affect the resonance and bass response of driver  202 . For example, the higher the acoustic mass of bass duct  606 , the lower the resonance and the more bass of earphone  100 . However, the size of the acoustic mass of bass duct  606  may be limited in that driver  202  must be large enough to drive the acoustic mass, and thus, cost and packaging size considerations may impose practical limitations on driver selection. Once an appropriate acoustic mass is selected to create the desired resonance and bass response for a practical driver  202 , the geometry of bass duct  606  may be optimized to fit within the available rear space. For example, to peg the acoustic mass at a desired value, as bass duct  606  length is shortened to fit behind chamber partition  508 , so must duct contour  510  area be decreased. However, the reduction in bass duct  606  size becomes limited by viscous and thermal losses, which roughly increase proportional to the inverse square of the duct contour  510  area, thereby increasing acoustic impedance of bass duct  606 . Therefore, a trade-off between duct size, and hence earphone size, and acoustic performance of bass duct  606  may exist. In an embodiment, bass duct  606  may be sized such that the acoustic losses through bass duct  606  are about twice the acoustic losses through vent port  402 . This may provide for a compact earphone with desirable bass response. Accordingly, an acoustic impedance of bass duct  606  may be greater than an acoustic impedance of vent port  402  and/or vent mesh  518  covering vent port  402 . In an embodiment, respective acoustic impedances of bass duct  606 , vent port  402 , and/or vent mesh  518  may be minimized to approximate zero as closely as possible and to remain less than the acoustic impedance of acoustic port  512  or acoustic mesh  516 . 
     Even in a case in which an acoustic impedance of a port, aperture, or volume is minimized, the acoustic impedance may nonetheless be greater than zero to achieve aesthetic or other functional purposes. For example, a mesh may cover a port to provide a visual distinctiveness to the port for aesthetic reasons, and thus, even if a mesh is used having a small mesh surface area to port cross-sectional surface area, e.g., less than about 75%, the acoustic impedance of the port may be greater than zero. Similar shrouding of ports may be used for the functional purpose of reducing the likelihood that external particles will enter the earphone rear space. For example, as described above, vent port  402  and/or vent mesh  518  may be essentially acoustically transparent. For example, the acoustic impedance of vent port  402  and/or vent mesh  518  may be on the order of about 10 Rayl, or less. More particularly, vent mesh  518  over vent port  402  may have a plurality of openings that are sized to resist ingress of dust, debris, sand, or other particles, but to provide minimal resistance to sound. The plurality of openings may have effective diameters of about 300 micron or less. For example, the plurality of openings may have effective diameters of about 200 micron, making them small enough to resist ingress of most sand particles, but having an acoustic impedance that approximates zero relative to the acoustic impedance of ambient air. In an embodiment, vent port  402  may be uncovered and ingress of particles into back volume  604  and bass duct  606  may be resisted by acoustic mesh  516  over acoustic port  512  and/or a duct mesh over duct port  612 . In another embodiment, bass duct  606  may not include a duct mesh, but may be tortuous such that particles that that enter duct port  612  through vent chamber  610  may be unlikely to migrate all the way to back volume  604  through bass aperture  514 . Thus, both vent port  402  and duct port  612  may be uncovered, open channels. Accordingly, it will be appreciated that ports and apertures of earphone  100  may be covered or uncovered to create the desired acoustic impedance and to reduce the likelihood of particles entering back volume  604 . 
     Still referring to  FIG. 10 , in an embodiment, earphone may incorporate active noise control elements such as microphones, analog circuits, or digital signal processing components to reduce unwanted environmental noise. More particularly, an ambient or reference microphone  1002  may be located in vent chamber  610  facing vent port  402  and/or the surrounding environment. Reference microphone  1002  may receive external sounds from the surrounding environment and convert the sounds into an electrical signal that is provided to signal processing circuitry, which may by internal or external to earphone  100 . Signal processing circuitry may use adaptive algorithms to analyze a waveform of the ambient sound and either phase shift or invert the waveform to create a cancellation signal. The cancellation signal may then be provided to driver  202 , or to an additional speaker housed in earphone  100 , to produce a cancellation sound that will destructively interfere with the ambient sound as it travels toward the ear canal. The volume of the perceivable ambient noise may be reduced accordingly. Furthermore, an error microphone  1004  may be included in earphone  100 , e.g., within or external to front wall  106 , and may be directed toward the user&#39;s ear. The error microphone  1004  may sense sound and return a feedback signal to the signal processing circuitry that may make additional adjustments to the noise cancellation signal based on a determination of how well the ambient noise is being cancelled, or in view of other sound quality characteristics determined from the feedback signal. 
     In an embodiment, one or both of reference microphone  1002  or error microphone  1004  may be used in a telephony application. More particularly, earphone  100  may include a microphone, e.g., reference microphone  1002 , which may be located inside or outside of housing  104  to act as a voice pick up to receive a user&#39;s speech. The received sound may be converted by the microphone to an electrical signal for further processing in a telephony use case. 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Metadata:
Filing Date: 20180316
Publication Date: 20201013
Grant Date: 20201013
Priority Date: 20140627
Inventors: AZMI, Yacine
ANDERSEN, ESGE B.
AASE, JONATHAN S.
Howes, Michael B.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/1016", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/2811", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2826", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1091", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/2849", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2823", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2826", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2849", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1091", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2823", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2826", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2849", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 54932045