Patent Publication Number: US-6990209-B2

Title: High directivity microphone array

Description:
This application is a Divisional application of prior application Ser. No. 09/478,268 filed on Jan. 5, 2000 now U.S. Pat. No. 6,473,514 entitled High Directivity Microphone Array. 

   TECHNICAL FIELD 
   This invention relates to the technical field microphone arrays and housing therefore. 
   BACKGROUND 
   Use of a microphone while operating a computer or similar terminal device has demanded a new type of highly directional microphone to selectively receive the voice of the speaker situated directly in front of it, but with the ability to cancel or reject sounds coming from other directions. This is particularly important in an open workstation environment where there is little sound insulation from the sides and rear. Furthermore, speech-to-text applications take accurate reception of the audio from the speaker all the more critical. 
   Prior art devices range from simple single unit element microphone with an adhesive base mounted on the top of a video monitor, to the use of headsets. The first solution is generally inadequate to provide sufficient sound isolation and the headset concept, while highly effective, requires the user to wear the headset in some cases still requires the user to be tethered to some part of the computer. 
   The present invention overcomes the problems inherent in prior “set top” mounted solutions while providing a highly direction microphone in a hands free, untethered environment. 
   The solution to the above problems lies in both the supporting electronics for the array and the cabinet design and microphone placement. The placement and electronics solutions are addressed in U.S. patent application Ser. No. 09/191,208 filed Nov. 12, 1998, which is specifically incorporated herein by reference. The solution to the cabinet is addressed in this application. 
   As to the cabinet, there is a need to mount the microphone array in a way to maximize its effectiveness, yet provide a convenient enclosure which will fit on monitors (or other fixtures like an automobile dashboard) of different sizes and shapes. Finally, it is important that a mobile solution be available so that the length of the array, which contributes to its effectiveness, will not detract from the transportability of the product. 
   It is also important that a structure be provided to warn the user to stay positioned in the field of optimum audio capture defined by the array. 
   The present invention addresses these issues and the invention comprises each individual solution as well as combinations of solutions. 
   BRIEF DESCRIPTION OF THE INVENTION 
   The invention can be characterized in many different ways and combinations. The following summary may be helpful in getting a general understanding of the invention in its many forms. Be aware however that the invention is defined by the claims which follow the specification and not by any summary information contained herein. 
   The invention relates to a microphone array preferably having an elongated housing for holding a series of spaced apart microphones. The housing is preferably formed in two half wings, the wings being hinged together at one of their ends to allow for folding at the hinge. 
   In one embodiment the housing has removable fee. 
   In another embodiment the feet are adjustable along a slot. 
   Another configuration of the array has an indicator which allows the user to know when he/she is speaking from the proper position, i.e. with the field of optimum audio reception. 
   Another configuration provides a locking mechanism to hold the winds in an extended open position, and additionally may provide a latching mechanism for maintaining the wings in a folded position (feet removed) for transport. 
   The array may also have structure for permitting the passage of wires through the hinge itself so that no exposed wires appear outside the housing. 
   The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description which follow more particularly exemplify these embodiments. 

   
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The figures form a part of the invention disclosure and are used to illustrate a preferred embodiment but not to limit the scope of the claims to that embodiment: 
     In the following, the invention will be described in more detail with reference to the drawing, where 
       FIG. 1  is a top perspective view of one the invention with feet removed; 
       FIG. 2  is a perspective view of like  FIG. 1 , but non folding, with feet shown; 
       FIG. 3  is a pop plan view with feet removed; 
       FIG. 4  is a front plan view with feet removed; 
       FIG. 5  is a rear perspective view, non folding, with feet attached; 
       FIG. 6  is a top perspective view with portions broken away; 
       FIG. 7  is a perspective view in a partially folded position; 
       FIG. 8  is a perspective view in a partially folded position; 
       FIG. 9  is a close-up perspective view of the hinge; 
       FIG. 10  is a view like  FIG. 9  except a wire path is shown; 
       FIG. 11  is a view like  FIG. 10  except that the removable hinge pin is fitted; 
       FIG. 12  is a view like  FIG. 11  with the hinge removed to show other elements; 
       FIGS. 13   a ,  13   b , and  13   c  are side, top and in plan views of the latching clip; 
       FIG. 14  is a perspective view of the latching clip; 
       FIG. 15   a  is an exploded perspective view of the latching clip in the housing; 
       FIG. 15  is a perspective view of the latching clip with portions removed; 
       FIG. 16  is a top perspective view of the lower housing portion as seen from the inside; 
       FIG. 17  is a view like  FIG. 16  except with microphone pods shown; 
       FIG. 18  is an exploded view of a microphone pod; 
       FIG. 19  is a bottom perspective showing feet in place (non-folding); 
       FIG. 20  is a bottom plan view; 
       FIG. 20  a is a perspective view of the bottom with cross section in shadow; 
       FIG. 21  is a perspective view the feet; 
       FIG. 22  is a side plan view of the array with feet; and 
       FIG. 23  is a bottom perspective close-up view of a locking recess. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A microphone array assembly  10  is shown generally in  FIGS. 1 , through  6 . It has a front face  12  with a series of slot apertures  14 . The slots are parallel apertures of varying depth as shown in  FIG. 2  from the most shallow on the outside to the deepest and tallest on the inside. The slots provide access to the microphone pods, which reside behind the slot apparatus. At approximately the center or midpoint along the elongated portion of the array is an aperture  16  which is used to provide a visual indication of in range placement. That is to say when the user is speaking into the array at the location within the optimum capture envelope of the array, the user will be able to see the illumination of the visual indicator, through aperture  16 . An LED or other illumination device  116  resides directly behind the aperture. Aperture  116  is preferably formed in a slot formation so as to limit the viewability of the illumination device to a limited angle off dead center. The angle of viewability is determined by the width, of the slot and the depth at which the illumination device is located relative to the front face of the aperture. These parameters must be adjusted to achieve a viewability angle not greater than the acceptable range of capture for the microphone array. In the alternative, a polarizing light source could be provided so that the desired limitation on the viewable extent of the indicator can be controlled by the polarization alone. 
   The aperture  16  and illumination device  116  need not be placed in the center point of the array, if the above parameter are adjusted to accommodate the off center placement. On the top side of the array are depressions  18  and at the forward most end of the depression is an opening  20  which provides pressure relief for the microphone pods situated thereunder. 
   The preferable configuration is a “set-top” arrangement where the array is removablely resting on the edge of a video monitor, auto dashboard, or the like. It is however possible to build this structure into the facing of a video monitor or equivalent. 
   On the lower side of the array are found two movable and removable feet  22 , shown in  FIGS. 20 ,  21 ,  22 . (A single foot or multiple feet are also possible.) Each foot is provided with a front lip  24  (see  FIG. 21 ) which is intended to overhang the monitor or other resting shelf on which the array is situated, and a resting surface area  26 , preferably covered by a gripping material such as neoprene. In the body of each foot is a concave recess  31  having a slot  30 , which terminates at least one end in a circular opening  32 . The concave recess appears a convex protrusion on the other side of the foot. The preferred shaped is oval or oblong though it could have parallel sidewalls, so long as it is curved. This circular opening  32  is sized to be slightly larger than a retaining cap  34 , which extends out of the underside  36  of the array. The retaining cap  34  has a head sized just smaller than that of opening  32  and a neck  35  (visible in part in  FIG. 16  and in shadow cross section in  FIG. 20   a ) just smaller than slot  30 . Neck  35  is long enough to just accommodate the thickness of material adjacent slot  30  so that the foot can slide in the space between cap  34  and the underside  36  array. On the underside of the array  36  ( FIG. 20 ) the convex surface  33  of the foot is mated with a similarly shaped concave depression  37  in underside  36 . The preferred shape of the depression  37  is circular as shown in  FIG. 17 . Though other shapes would suffice so long as the shape of the foot at the contact points with the underside would be in a slideable configuration relative to each other as the foot was moved along the slot  30 . The resulting configuration provides a foot with full movement in 2 planes (x+y), i.e. the foot can tip forward or backward to adjust for the angle at which it contacts the monitor edge (or similar) and it may rotate right or left for similar reasons. 
   The right/left rotation is restricted if the neck is a planer member (parallel sides) and sized to fit the slot  30 . 
   If the neck is cylindrical, full rotation is possible. Diamond or oval shapes will provide limited rotational freedom. 
   This permits feet  22  to be captured by the cap  34  and slide comfortably down slot  30  to accommodate different angles or orientation as maybe required by environmental considerations (such as the height of the user, the size of the monitor, the angle of the monitor, etc.). Each foot  22  is independently adjustable of the other. The feet  22  are removable for storage and transport. 
   In the preferred embodiment of the invention, the array  10  is foldable into two sections (wings) of preferably equal length  120  and  140  see  FIG. 7 and 8 . The halves are joined at a hinge  160 . On half  140  there are preferably two locking projections  142  to be received within two locking apertures  144  on side  120 . The projections have a wide first portion  146  and then a narrower neck  148  and a wider base portion  150 . Apertures  144  have a latching or retaining clip  160 . (See  FIGS. 13   a, b, c ,  14  and  15 ) located just inside the housing adjacent apertures  144 . The locking clip  160  includes a body element  162  with flanges  164 . Apertures  168  are provided to receive a bias wire  170  which maintains flanges  164  biased in a predetermined horizontally opposed position. Locking mechanism  160  is maintained just behind apertures  144 . When projections  142  pass through apertures  144 , projections  164  on the U shaped locking clip  160  are briefly spread but under pressure of wire  170  quickly retract to engage the recess  148  in projections  142  thereby maintaining the two halves of the microphone array a locked-open position. When the array is folded, the reverse occurs permitting the removal of projections  142 . Clips  160  are held in place adjacent apertures  144  by simple wall formations in the housing. 
   The array is preferably hinged see  FIGS. 7 through 12 . The hinge element  260  performs two functions. First, it allows the two halves  120  and  140  to swing on the hinge axis, but it also permits the passage of electrical conductors from one half to the other, without exciting the housing and exposing them to possible damage. Each microphone in the array has conductors which must be brought back from their respective housing halves to a circuit for signal processing. Therefore, hinge  260  has a hollow core and aperture on each half of the microphone array. 
   Turning to  FIG. 10 , hinge  260  is held in place by two halves of a hinge pin (the lower one held inside cap  270  and not otherwise visible and the upper hinge pin  280  is slideably removable from hinge  260 ). Hinge pin  280  has an aperture  300  in its side wall corresponding to a notch  320  in the hinged body itself which permits passage of wires  301  to pass into the hollow core of the hinge pin. Hinge pin  280  is removably maintained within the hinge body  260  by a baisable latch member  330 , which engages a like-shaped receiving portion  340  on the hinge body  260 . A like aperture  302  (See  FIG. 12 ) on the other side of the hinge body  260  permits the exit of wires that were fed through aperture  300  into the hinge body and out into the other half of the microphone array via aperture  302 . Consequently, the wires are maintained completely within the structure and are not visible to the user. 
   Microphone pod units  400  (see  FIGS. 16 through 18 ) sit behind slotted apertures  14  and are confined in defined recesses  410  on both halves  420  and  430  (upper and lower) of the housing which comprises each wing ( 120 ,  140 ) of the microphone array housing. As mentioned earlier, apertures  20  are provided in both upper and lower halves of each wing and within microphone recesses  410 . They provide pressure release against the incoming sound pressure. 
   The preferred construction of each microphone pod  400  is shown in  FIG. 18 . The main body is formed of a microphone receiving mount  500  having an aperture  502  sized to receive microphone element  504  and a further vertically oriented aperture  506  sized to receive a sound deadening and pressure relief block  508 , typically made of rubber material and having an aperture  510  which also provides rear passage for the microphone wires. It is block  508  that engages apertures  20  in the two halves of the housing. 
   In front of each microphone unit  400  is a noise-canceling block  512  made of typical material found on the face of microphone elements. 
   The circuitry for interconnecting microphone units  400  is described in detail in U.S. patent application Ser. No. 09/191,208 fled Nov. 12, 1998 and incorporated herein. 
   In the folded position, the wings  120 ,  140 , can be maintained in abutment by an option pin latch, comprising a recess  600 , and projection  602 . Actually,  600  and  602  do not mate with each other but with their reverse image counterpart (not shown) on the other wing. (That is, where projection  602  is located on this wing, a recess  600  will be on the other wing). 
   Recess  600  includes a ridge  604  (also shown in the cross section) and a like ridge  606  on the projection  602 . The ridges are sized so that the projection cannot easily pass into the recess without a frictional encounter as the two ridges pass each other. In the alternative the diameter of projection  602  can simply be just larger than the inner diameter of ridge  604 , which will insure a friction fit throughout. 
   It is understood that this has been a detailed description of the preferred embodiment, but that the invention encompasses a much broader range of possible substitutions of element to achieve the objection of this invention. 
   As noted above, the present invention is applicable to video display monitors, dashboards of vehicles, but that the inventive concepts can be applied anywhere where highly directional microphones in a hands-free is advantageous, including as a built in feature of any of the above. Accordingly, the present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification.