U.S. patent application number 14/885928 was filed with the patent office on 2017-04-20 for microphone porting structure and assembly for a communication device.
The applicant listed for this patent is MOTOROLA SOLUTIONS, INC. Invention is credited to PATRICK S. CLAEYS, ANDREW P. MIEHL, KARL F. MUELLER.
Application Number | 20170111751 14/885928 |
Document ID | / |
Family ID | 58524815 |
Filed Date | 2017-04-20 |
United States Patent
Application |
20170111751 |
Kind Code |
A1 |
MIEHL; ANDREW P. ; et
al. |
April 20, 2017 |
MICROPHONE PORTING STRUCTURE AND ASSEMBLY FOR A COMMUNICATION
DEVICE
Abstract
A microphone porting structure, comprises a substrate (312)
having a bearing surface and a porting through-hole (344) formed
therethough for aligning with a microphone port of a bottom ported
microphone (334). The bearing surface provides an area against
which to seal and the through-hole provides for acoustic path
alignment for the audio ports of paired bottom ported microphones
mounted to a printed circuit board.
Inventors: |
MIEHL; ANDREW P.; (BOCA
RATON, FL) ; CLAEYS; PATRICK S.; (PEMBROKE PINES,
FL) ; MUELLER; KARL F.; (SUNRISE, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MOTOROLA SOLUTIONS, INC |
SCHAUMBURG |
IL |
US |
|
|
Family ID: |
58524815 |
Appl. No.: |
14/885928 |
Filed: |
October 16, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04R 2201/003 20130101;
H04R 31/006 20130101; H04R 2499/11 20130101; H04R 2201/401
20130101; H04R 19/005 20130101; H04R 1/406 20130101; H04R 1/342
20130101 |
International
Class: |
H04R 31/00 20060101
H04R031/00; B81B 7/00 20060101 B81B007/00 |
Claims
1. A microphone porting structure, comprising: a substrate having a
bearing surface and a porting through-hole formed therethrough, the
porting through-hole for aligning with a microphone port of a
bottom ported microphone; and wherein the bearing surface provides
a surface against which to seal and the through-hole provides an
acoustic path for the bottom ported microphone.
2. The microphone porting structure of claim 1, wherein the
substrate has a predetermined thickness with a straight
through-hole.
3. The microphone porting structure of claim 1, wherein the bearing
surface is raised atop of the through-hole and the through-hole is
surface mountable.
4. The microphone porting structure of claim 1, wherein the
substrate has a predetermined thickness and the through-hole
integrated therein is bent.
5. The microphone porting structure of claim 1, wherein the
substrate is a surface mount substrate.
6. The microphone porting structure of claim 1, wherein the
substrate is formed of plastic or metal.
7. The microphone porting structure of claim 1, wherein the top
bearing surface has a cut-away section to allow components to be
placed below the bearing surface on to a printed circuit board
(pcb).
8. A microphone mounting assembly, comprising: a printed circuit
board (pcb) having an upper and lower surfaces; a first microphone
porting structure mounted to the upper surface of the pcb; a second
microphone porting structure mounted to the lower surface of the
pcb; a first acoustic port passing through the upper and lower
surfaces of the pcb; a second acoustic port passing through the
upper and lower surfaces of the pcb; a first bottom ported
microphone mounted to the lower surface of the pcb, the first
bottom ported microphone having a first bottom port aligned with
the first acoustic port of the pcb and the first microphone porting
structure; and a second bottom ported microphone mounted to the
upper surface of the pcb, the second bottom ported microphone
having a second bottom port aligned with the second acoustic port
of the pcb and the second microphone porting structure; and wherein
the first microphone porting structure has a broad planar surface
that overlaps at least partially over the second bottom ported
microphone.
9. The microphone mounting assembly of claim 8, wherein the second
microphone porting structure has a bearing surface that overlaps at
least partially over the first bottom ported microphone mounted to
the lower surface of the pcb.
10. The microphone mounting assembly of claim 8, wherein the
substrate has a predetermined thickness with a straight
through-hole.
11. The microphone mounting assembly of claim 8, wherein the
bearing surface is raised atop of the through-hole and the
through-hole is surface mountable.
12. The microphone mounting assembly of claim 8, wherein the
substrate has a predetermined thickness and the through-hole
integrated therein is bent.
13. The microphone mounting assembly of claim 8, wherein the
substrate is a surface mount substrate.
14. The microphone mounting assembly of claim 8, wherein the
substrate is formed of plastic, metal or printed circuit board
material.
15. The microphone mounting assembly, of claim 8, wherein the first
and second microphone porting structures provide room for opposing
first and second bottom ported microphones to be closer
together.
16. A microphone mounting assembly, comprising: a first microphone
porting structure fitting at least partially over a second,
bottom-ported, surface mounted (SMT) miniature microphone that is
mounted on an upper surface of a printed circuit board (pcb); a
second microphone porting structure fitting at least partially over
a first bottom-ported, SMT miniature microphone that is mounted on
a lower surface of the pcb; and a first seal coupled over the first
planar surface above the first microphone porting structure and the
second bottom-ported SMT, miniature microphone; and a second seal
coupled over the second planar surface above the second microphone
porting structure and the first bottom-ported, SMT miniature
microphone.
17. The microphone mounting assembly, of claim 16, wherein spacing
requirements limit microphone placement on the pcb.
18. The microphone mounting assembly, of claim 16, wherein the
first and second microphone porting structures provide room for
opposing first and second microphones to be closer together.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to microphone
porting and more particularly microphone porting in communication
devices.
BACKGROUND
[0002] Today's portable communication devices, operated in a public
safety environment, often utilize a plurality of microphones for
noise cancellation of background noise. Some microphone
arrangements also need to be mounted in pairs to provide beam
forming (directivity to source/user). Unlike sealing and porting
needs of a singular microphone, the porting and sealing of a
plurality of microphones face different acoustical problems and
physical implementation challenges. Product use requirements, in
combination with the technical requirements of noise canceling
algorithms, require that microphones be properly positioned with
respect to each other.
[0003] Some microphone array arrangements are challenged with
alignment between microphones in the z-direction (thickness of the
product), such as in handheld radio applications where the device
is held away but facing the user. FIG. 1 is a microphone porting
structure 100 in accordance with the prior art. While the porting
structure 100 provides space saving for top ported microphones 102,
104 mounted to a printed circuit board (pcb) 106 and establishes a
noise cancelling vector that is normal to the pcb, however the
outward porting makes these devices difficult to seal and the
acoustic performance tradeoffs associated with top ported
microphones makes them undesirable, particularly for beam forming
applications.
[0004] Accordingly, there is a need for improved microphone
porting. Improved microphone porting that would further facilitate
the ability to seal the microphone in a portable communication
device would be a further desired benefit.
BRIEF DESCRIPTION OF THE FIGURES
[0005] The accompanying figures where like reference numerals refer
to identical or functionally similar elements throughout the
separate views and which together with the detailed description
below are incorporated in and form part of the specification, serve
to further illustrate various embodiments and to explain various
principles and advantages all in accordance with the present
invention.
[0006] FIG. 1 is a prior art microphone mounting assembly in
accordance with the prior art.
[0007] FIG. 2 is a partial cut-away of a microphone mounting
assembly distance problems.
[0008] FIG. 3 is a partial cut-away of a microphone mounting
assembly having microphone porting structures formed in accordance
with another embodiment.
[0009] FIG. 4 is a partial cut-away of a microphone mounting
assembly having microphone porting structures formed in accordance
with another embodiment.
[0010] FIGS. 5A and 5B are isometric views of printed circuit
boards having the microphone porting structures formed in
accordance with an embodiment in a communication device.
[0011] Skilled artisans will appreciate that elements in the
figures are illustrated for simplicity and clarity and have not
necessarily been drawn to scale. For example, the dimensions of
some of the elements in the figures may be exaggerated relative to
other elements to help to improve understanding of embodiments of
the present invention.
DETAILED DESCRIPTION
[0012] Before describing in detail embodiments that are in
accordance with the present invention, it should be observed that
the embodiments reside primarily in a microphone porting structure
and a microphone mounting assembly for porting bottom ported
microphone pairs mounted to a printed circuit board of a
communication device. The use of the structure in the porting of
microphone pairs improves the ability to integrate a large number
of microphones within tight space constraints and facilitates the
sealing of the microphones.
[0013] Bottom ported micro-electromechanical (MEMS) microphones can
be used in a variety of communication products, both consumer and
commercial products, and acoustic sealing and placement of such
devices impacts performance. The use of bottom ported MEMS
microphones is sometimes considered a constraint or requirement for
the type of microphone used in certain products, such as the public
safety products. Product use case requirements, in combination with
technical requirements of noise cancelling algorithms, particularly
beam forming algorithms, often dictate the positioning of
microphones with respect to each other. However, the physical real
estate is often limited and the required porting of microphone
pairs can become problematic.
[0014] Additionally, ruggedized communication devices, such as
public safety radios and their accessories, require that the
microphones be sealed with a breathable, waterproof membrane. All
of these necessary physical traits for a waterproof noise
cancelling microphone system that uses bottom ported microphones
present serious challenges in achieving appropriate porting.
[0015] FIG. 2 is a partial cut-away view of a microphone mounting
assembly 200 illustrating an example of pre-established spacing
requirement challenges faced by some products. The microphone
mounting assembly 200 comprises a printed circuit board (pcb) 206
having an upper surface 210 and a lower surface 220. A first
acoustic port 222 passes through the upper and lower surfaces 210,
220 of the pcb 206, and a second acoustic port 224 passing through
the upper and lower surfaces 210, 220 of the pcb 206. The distance
between the first and second acoustic ports 222, 224 of the pcb 206
has been pre-established by design restrictions establishing keep
out areas. To bring the bottom mounted microphone components 202,
204 any closer together from this point in order to improve
alignment to the vector that is normal to the pcb surface would
result in violation of the sealing requirement. At best, a seal
212, 214 can be placed as shown. The embodiments to be described
herein are directed to a microphone porting structure that will
allow the bottom ported microphones to be brought closer together
by providing an improved acoustic path and an improved ability to
seal.
[0016] Accordingly, the components have been represented where
appropriate by conventional symbols in the drawings, showing only
those specific details that are pertinent to understanding the
embodiments of the present invention so as not to obscure the
disclosure with details that will be readily apparent to those of
ordinary skill in the art having the benefit of the description
herein.
[0017] In this document, relational terms such as first and second,
top and bottom, 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 terms "comprises," "comprising," 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 preceded by
"comprises . . . a" does not, without more constraints, preclude
the existence of additional identical elements in the process,
method, article, or apparatus that comprises the element.
[0018] Briefly, in accordance with the various embodiments, there
is described herein a microphone porting structure for a bottom
ported surface mount microphone comprising a substrate having a
planar, bearing surface and a porting through-hole formed
therethrough. The substrate formed in accordance with the various
embodiments comprises a predetermined thickness with the planar,
bearing surface with the through-hole that facilitates acoustic
porting and sealing. The sealing may be acoustical sealing,
environmental sealing and/or sealing for assembly tolerances. For
example, the substrate may be formed of plastic, metal, or pcb
(FR4) having predetermined thickness with a straight porting
through-hole. In other embodiments, the substrate may be formed
such that the planar bearing surface is raised atop of the porting
through-hole by a certain distance, leaving room for components
underneath, and the through-hole is surface mountable. In other
embodiments, the substrate may be formed to have a planar surface
having a predetermined thickness within which is formed a bent
porting through-hole for adjusting porting alignment. All of these
embodiments provide a means for reliable sealing while allowing for
tighter microphone spacing and will be shown
[0019] FIG. 3 is a partial cut-away of a microphone mounting
assembly 300 having microphone porting structures 312, 314 formed
in accordance with an embodiment. In this embodiment, a maximum
printed circuit board "greenspace" savings is achieved by the
microphones being closer together through the use of broad, planar
surface microphone porting structures 312, 314. Each microphone
porting structure 312, 314 formed in accordance with the embodiment
provides a large bearing surface that can advantageously be used to
seal against and can thus provides both environmental sealing and
absorption of assembly and system tolerances. In accordance with
the embodiments, each seal is established above the body of the
opposing microphone.
[0020] In accordance with this embodiment, the microphone mounting
assembly 300 comprises a printed circuit board (pcb) 306 having
upper and lower surfaces 310, 320. A first acoustic port 322 passes
through the upper and lower surfaces 310, 320 of the pcb 306, and a
second acoustic port 324 passes through the upper and lower
surfaces 310, 220 of the pcb 306. A first bottom ported microphone
302 having a first bottom microphone port 332 is mounted to the
upper surface 310 of the pcb 306 in alignment with the first
acoustic port 322 of pcb 306. A second bottom ported microphone 304
having a second bottom microphone port 334 is mounted to the lower
surface 320 of pcb 306 in alignment with the second acoustic port
324 of pcb 306. The microphones may be, for example, bottom ported
miniature surface mount (SMT) microphones.
[0021] In accordance with this embodiment, a first microphone
porting structure 312 is mounted to the lower surface 320 of the
pcb 306, and a second acoustic porting structure 314 is mounted to
the upper surface 310 of the pcb 306. The second bottom ported
microphone 304 having the second bottom microphone port 334 is
aligned with the second acoustic port 324 of the pcb 306 and the
second acoustic porting structure 314. The first bottom ported
microphone 302 is mounted to the upper surface 310 of the pcb 306,
and the first bottom ported microphone 302 having a first bottom
port 332 is aligned with the first acoustic port 322 of the pcb 306
and the first microphone porting structure 312.
[0022] In this embodiment the first microphone porting structure
312 is raised at throughole 342, and the second acoustic porting
structure is raised and throughole 344, forming an umbrella area of
space. The umbrella area provides the space necessary to move
microphones closer together while still creating bearing surfaces
for seals, such as seal 350. The additional space below the planar
surface of structures 312 and 314, provides room for components,
for example components 330, to be mounted to the pcb 306. In
accordance with the various embodiments, by providing room for the
opposing microphone, the alignment of the acoustic ports to the pcb
normal vector can be improved.
[0023] The microphone mounting assembly 300 using microphone
porting structures 312, 314 for aligning bottom ported microphones
302, 304 allows the microphones to be brought closer together in
the plane of a printed circuit board (pcb) 306, and provides for a
broad, planar sealing surface to be established above the body of
the opposing microphone. The microphone mounting assembly can be
accurately placed using automated pick and place machines, thereby
significantly reducing the assembly tolerance between the
structures 312, 314 and the adjacent microphone body 302, 304.
[0024] The more alignment there is of the microphones themselves to
the vector that is normal to the pcb surface, the fewer lateral
downstream structures are needed to realign the external sound
sampling points. Any lateral acoustic porting that does not
directly extend to the outer surface of the communication device is
additional acoustic port length that can serve to lower the
Helmholtz resonance of the acoustic porting system, potentially
bringing it into the use case frequency band, adversely affecting
the microphone performance
[0025] FIG. 4 is a partial cut-away of a microphone mounting
assembly having microphone porting structures 412, 414 formed in
accordance with another embodiment. This embodiment provides for
further alignment correction of the porting of microphone pairs in
accordance with another embodiment. In this case, the structure is
configured to both improve alignment of the microphone bodies 402,
404 as much as possible and redirect the acoustic port such that
perfect alignment of the acoustically active ports to the pcb 406
normal vector is achieved. In this embodiment the substrate has a
predetermined thickness and the through-hole integrated therein is
bent. In this embodiment the first microphone porting structure 412
has a first bent through-hole 442 formed therein, and second
microphone porting structure 414 has a second bent through-hole 444
formed therein. The first microphone porting structure 412 fits at
least partially over a second bottom-ported, surface mounted (SMT)
miniature microphone that is mounted on a lower surface 420 of a
pcb 406. A second microphone porting structure 414 fits at least
partially over a first bottom-ported, SMT miniature microphone 402
that is mounted on an upper surface of the pcb 406. The alignment
of the microphone porting structure 412 with the pcb acoustic port
422, and the alignment of the microphone porting structure 414 with
the pcb acoustic port 424--in conjunction with the bent
through-holes 442, 444 provide for back to back audio alignment of
the audio porting.
[0026] In this embodiment, a more filled in structure can be used
to accommodate the bent porting, as opposed to the umbrella
structure, such as formed of molded plastic. The sealing on this
type of structure can be more three-dimensional if desired (i.e.
planar on top like 350 and then extending down the body of the
microphone porting structure).
[0027] Hence, perfect alignment of the microphone's acoustically
active ports 432, 434 to the pcb 406 normal vector is achieved
through the use of the microphone porting structures 412, 414. Each
structure is easy to manufacture and easy to pick and place on a
circuit board. This configuration is of particular benefit in the
context of ultrathin communication devices where there is very
little product thickness/depth that might be exploited by other
lateral structures to recover from bottom port microphone body
misalignment.
[0028] FIGS. 5A and 5B show printed circuit board 502 from opposing
sides having the microphone porting structures formed in accordance
with an embodiment in a communication device. View 500 shows bottom
ported microphone 502 and microphone porting structure 512. View
540 shows bottom ported microphone 504 and microphone porting
structure 514. Microphone porting structure 512 provides porting
for bottom ported microphone 504. Microphone porting structure 514
provides porting for bottom ported microphone 502. The bearing
surface is shown on each microphone porting structure 512, 514
which provides a surface upon which to seal. This embodiment has
the bent porting within each microphone porting structure.
[0029] Thus, the various embodiments have provided for a microphone
porting structure that provides improved porting for bottom ported
microphones. The substrate having a planar bearing surface and a
porting through-hole formed therethough, allow for aligning the
microphone port of the bottom ported microphone closer to another
microphone port of paired microphones. The bearing surface provides
a surface against which to seal and the through-hole provides an
acoustic path for a bottom ported microphone.
[0030] In the foregoing specification, specific embodiments of the
present invention have been described. However, one of ordinary
skill in the art appreciates that various modifications and changes
can be made without departing from the scope of the present
invention as set forth in the claims below. Accordingly, the
specification and figures are to be regarded in an illustrative
rather than a restrictive sense, and all such modifications are
intended to be included within the scope of present invention. The
benefits, advantages, solutions to problems, and any element(s)
that may cause any benefit, advantage, or solution to occur or
become more pronounced are not to be construed as a critical,
required, or essential features or elements of any or all the
claims. The invention is defined solely by the appended claims
including any amendments made during the pendency of this
application and all equivalents of those claims as issued.
* * * * *