Patent Publication Number: US-9906867-B2

Title: Surface acoustic transducer

Description:
CLAIM OF PRIORITY 
     The present application is a continuation-in-part application of previously filed, now pending application having Ser. No. 14/942,569, filed on Nov. 16, 2015, which matured into U.S. Pat. No. 9,621,994 on Apr. 11, 2017, and is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention provides for a surface acoustic transducer, and accompanying systems and methods, optimally structured for an aircraft cabin. Specifically, a unique structural combination is provided in order to protect the excursion of a voice coil assembly (primary assembly) relative to a magnet, such as to mitigate the effects of external forces or interference. Further, a larger excursion range is provided by a spider in conjunction with a higher wattage voice coil, in order to allow for a richer sound range provided by the surface acoustic transducer. 
     BACKGROUND OF THE INVENTION 
     Where traditional loud speakers create sound by converting electric signals into mechanical motion in order to vibrate a diaphragm or cone, surface acoustic transducers operate to produce sound without a cone. That is, a surface acoustic transducer operates by attachment to a surface, such as an existing panel or wall made of various materials, and directing vibrations directly onto the surface in order to create sound. 
     Surface acoustic transducers are generally known in the art. For instance, a surface acoustic transducer might be created by merely removing the enclosure and cone from a traditional loud speaker or speaker driver, and attaching it to an external vibrational surface in order to create sound. However, although surface transducers have been known for some time, few have ever achieved commercial success due to the technical limitations of these transducers, and the resulting poor quality of sound by merely attaching the transducers to various surfaces. 
     Specifically, one limitation of surface acoustic transducers is due to the lack of a mechanical excursion, which causes an absence of highs and lows in sound frequency. For example, rather than achieving a rich bass sound, regular surface acoustic transducers have limited frequency response resulting in a lower quality narrow band response as compared to traditional loudspeakers. Another issue with surface transducers is the effect of the attached bracket surface or external housing for mounting the surface transducers. That is, structurally, current surface mounted transducers do not account for movement or variation of the vibrational surface to which the surface transducer is attached. For example, a person leaning against a wall or surface to which the surface transducer is attached to would have a drastic impact on the sound or sound quality being reproduced due to potential deflection of the transducer onto adjacent surfaces behind the application. 
     Therefore, there is a need in the industry for an improved surface acoustic transducer that produces a better sound and overcomes the particular problems described above. 
     SUMMARY OF THE INVENTION 
     The present invention meets the existing needs described above by providing for a structurally unique surface acoustic transducer and accompanying systems and methods. Specifically, the present invention provides for a surface acoustic transducer structured for producing high quality sound by vibrating an external surface. In a preferred embodiment of the present invention, the surface acoustic transducer of the present invention is optimally structured for producing high quality sound within an aircraft cabin. Of course, the present transducer may also be further configured and utilized to vibrate other surfaces. 
     Accordingly, in initially broad terms, a surface acoustic transducer of the present invention comprises a primary assembly and a transducer housing structured to retain the primary assembly therein. 
     The primary assembly is structured to house a voice coil assembly, include a voice coil former and a voice coil wire, and optionally a coupler ring. The primary assembly may form a substantially cylindrical shape, with a portion of its proximal end protruding outwardly from the transducer housing. The magnet is disposed at a distal end of the primary assembly. The coupler ring may be attached to a proximal end of the primary assembly. The primary body portion of the primary assembly may be formed from the voice coil former, having a voice coil wire wound in surrounding relations to at least a portion thereof. 
     The transducer housing may comprise a flange structure and a yoke structure, a spider, as well as a magnet, and top shunt plate attached and/or disposed therein. The flange structure forms a proximal portion of the transducer housing and the yoke structure forms a distal portion of the transducer housing. The yoke may be coupled or movably attached to a distal end of the primary assembly. The top shunt plate may be juxtaposed to a distal end of the primary assembly, and between the magnet and the primary assembly. More specifically, a top shunt plate may be disposed substantially within an interior of the voice coil former, and the voice coil wire may be wound external to the voice coil former at a portion thereof, such as to be disposed in a substantially overlying position relative to an external edge of the top shunt plate. The magnet may be attached and/or disposed to a distal surface of the transducer housing, such that a portion of the edge of the magnet is in overlying position relative to the voice coil wire of the voice coil assembly. The flange may be disposed in surrounding relation to an external surface of said voice coil assembly. A terminal attachment may be attached to a portion of the flange, and structured and disposed to receive an electrical input. A spider may be coupled to the flange in juxtaposing surrounding relation with the primary assembly, and more particularly the voice coil assembly forming a portion thereof. The spider may be disposed to mechanically dampen and/or at least partially impede the movement of the voice coil assembly as it is electrically excited from an electrical input signal. 
     An external housing or mounting bracket may further be provided to at least partially enclose the transducer housing therein. The external housing may comprise a cylindrical retaining wall of a rigid composition, and an excursion cover disposed and/or affixed thereon for protecting the transducer yet at the same time allowing for the excursion of the primary assembly therein. 
     These and other objects, features and advantages of the present invention will become clearer when the drawings as well as the detailed description are taken into consideration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which: 
         FIG. 1  is a perspective external view of a surface acoustic transducer in one embodiment of the present invention. 
         FIG. 2  is a bottom profile external view of the surface acoustic transducer of  FIG. 1 . 
         FIG. 3A  is a side profile external view of the surface acoustic transducer of  FIG. 1   
         FIG. 3B  is a side profile partially cut away view of the surface acoustic transducer of  FIG. 1 . 
         FIG. 4A  is another side profile cut away view of the surface acoustic transducer of  FIG. 1 . 
         FIG. 4B  is an expanded view of a cross section of the surface acoustic transducer shown in  FIG. 4A . 
         FIG. 5  is a profile view of a coupler ring forming part of the surface acoustic transducer of the present invention. 
         FIG. 6  is a profile view of the coupler ring of  FIG. 5  in connection with a voice coil assembly forming part of the surface acoustic transducer of the present invention. 
         FIG. 7  is a profile view of a magnet forming part of the surface acoustic transducer of the present invention. 
         FIG. 8  is a profile view of a flange forming part of the surface acoustic transducer of the present invention. 
         FIG. 9  is a profile view of a spider forming part of the surface acoustic transducer of the present invention. 
         FIG. 10  is a profile view of a top shunt plate forming part of the surface acoustic transducer of the present invention. 
         FIG. 11  is a profile view of a yoke forming part of the surface acoustic transducer of the present invention. 
         FIG. 12  is a profile view of a surface acoustic transducer mounted within an external housing. 
         FIG. 13A  is a profile view of the external housing of  FIG. 12 . 
         FIG. 13B  is a top down view of the external housing of  FIG. 12 . 
         FIG. 13C  is a side view of the external housing of  FIG. 12 . 
         FIG. 14  is a schematic view of an active noise cancellation system utilizing one or more of the surface acoustic transducers of  FIG. 1  mounted along a periphery of an aircraft window panel via the external housing of  FIG. 12 . 
         FIG. 15  is a schematic view of another active noise cancellation system utilizing one or more of the surface acoustic transducers of  FIG. 1  mounted along a periphery of an aircraft window area via the external housing of  FIG. 12 . 
         FIG. 16  is an isolated cross section view demonstrating a preferred use of an adhesive to secure the mounting brackets to an underlying surface. 
     
    
    
     Like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     As illustrated by the accompanying drawings, the present invention is directed to a surface acoustic transducer. In a preferred embodiment, the surface acoustic transducer of the present invention is optimally structured, as described below, for producing high quality sound within an aircraft cabin by vibrating its interior cabin walls, bulkheads, and/or windows. Of course, the present surface acoustic transducer may also be utilized to vibrate other surfaces. Specifically, the surface acoustic transducer of the present invention includes a transducer housing structured to at least partially enclose a primary assembly having a voice coil assembly and a magnet. In an embodiment, the transducer housing may further be mounted within an external housing or mounting bracket having a rigid retaining wall and an excursion cover. This excursion cover may be formed of a malleable helix structure such as to protect the surface acoustic transducer from external disturbance, yet at the same time allow for an excursion of the transducer via the excursion cover. This prevents or minimizes the distortion of sound when, for example, a person leans against a cabin wall to which a surface acoustic transducer is attached or other surfaces or materials that are in close or contacting proximity to the surface acoustic transducer, all without sacrificing the sound range and quality of the transducer. 
     As schematically represented,  FIGS. 1 and 2  illustrate a surface acoustic transducer  100  of the present invention.  FIG. 1  provides a perspective view of the present transducer  100 , and  FIG. 2  provides a bottom profile view of the present transducer  100 . As shown initially, the transducer  100  may exteriorly comprise a transducer housing  120  and a primary assembly  110  retained therein. 
     The primary assembly  110  may form a substantially cylindrical shape and may comprise and/or be formed at least partially from a voice coil assembly  117 , with at least a portion of its proximal end protruding outwardly from the transducer housing  120 . The transducer housing  120  may comprise a flange  103  forming a proximal portion of the transducer housing  120 , and a yoke  104  forming a distal portion of the transducer housing  120 . Further, the distal end of the primary assembly  110  may terminate within the yoke  104 . 
     The flange  103  may be coupled to a proximal end of said transducer housing  120 , forming a portion thereof. Said flange  103  being disposed in surrounding relations to the primary assembly  110 . The flange  103  may comprise a terminal attachment  105  coupled to an end or edge of the flange as shown in the accompanying Figures. The terminal attachment  105  being structured with at least a positive terminal portion and negative terminal portion for receiving power from a power source, and further relay the power to a voice coil assembly  117 . In at least one embodiment of the present invention, the transducer housing  120 , or more particularly the diameter of the flange  103  comprises a diameter of between 25 mm to 30 mm. 
     The yoke  104  may be coupled to a distal end of said transducer housing  120 , forming another portion thereof. The yoke  104  may be coupled in at least partially surrounding relation relative to a distal portion of the primary assembly  110 . 
     Drawing attention to  FIGS. 3A and 3B , respective side profile and partial cutaway side profile views of the surface acoustic transducer  100  are shown. As in  FIG. 3A , the primary assembly  110  may further comprise a coupler ring  101  attached to a proximal end thereof. The primary assembly  110  may comprise a voice coil assembly  117  disposed between the coupler ring  101  and the yoke  104 . 
     Drawing attention to  FIG. 3B , a partial cutaway view of the surface acoustic transducer  100  further illustrates a spider  102  at least partially coupled to the flange  103 , and structured to dampen the movement of the primary assembly  110  comprising the voice coil assembly  117 . As such, the spider  102  may be coupled in surrounding relations to the primary assembly  110 , or more specifically, a portion of the voice coil assembly  117 . A magnet  111  providing a magnetic field may be coupled to a distal end of the transducer housing  120  and disposed in proximity to a distal end of the primary assembly  110  and/or voice coil assembly  117 , and the voice coil wires  116  thereof, such as when the voice coil assembly  117  is in a resting state. A top shunt plate  112  may form circumferentially along a distal portion of the voice coil assembly  117 , and disposed in juxtaposing relations to the magnet  111 . Further, in at least one embodiment, the shunt plate  112  may have a slanted edge to prevent the build up of the magnetic field on the corners and improve the BL curve representing force factor relative to excursion distance. 
     Drawing attention to  FIG. 4A  illustrating a cutaway view of the surface acoustic transducer  100 , and more particularly  FIG. 4B  illustrating an exploded view of the cross section C, the voice coil assembly  117  comprises a voice coil former  115  and voice coil wire  116 . The voice coil former  115  may comprise a cylindrical shape and may form a part or a portion of the voice coil assembly  117 . The voice coil wire  116  may be wound in surrounding relations to at least a portion of the voice coil former  115 , as illustrated in  FIG. 4B , such that the voice coil wire  116  may be at least partially immersed within the magnetic field provided by the magnet  111 . 
     In at least one embodiment of the present invention, a top shunt plate  112  may be disposed in substantially overlying relations relative to the voice coil wire  116 , while only a portion of the magnet  111  is disposed in overlying relations relative to the voice coil wire  116 , when the voice coil assembly  117  is at a rest state. Further, the magnet  111  of the present invention is preferably mounted at a distance of approximately 0.33 mm away (or providing a gap of 0.33 mm) from the voice coil assembly  117 , to ensure that the magnet  111  and voice coil assembly  117  do not collide. In other embodiments, the gap will be preferably between various ranges of 0.25 to 0.4 mm. When the voice coil assembly  117  is in an excited state, such as when electrically excited by an input electrical signal via the terminal attachment  105  from an external power source, the voice coil assembly  117  may move in accordance with the received signal. The spider  102  coupled to the flange  103  is in juxtaposing surrounding relations with the voice coil assembly  117 , such as to abut the voice coil former  115  in order to at least partially impede and/or dampen its movement. In a preferred embodiment, the spider  102  is formed of a flexible material such as to allow for a large excursion range or movement of the voice coil assembly  117 . 
     Drawing attention back to  FIG. 4A , and in at least one embodiment of the present invention, the transducer housing  120  is structured to house the primary assembly  110  including the voice coil assembly  117 , and the magnet  111 , such that the voice coil assembly  117  is disposed in movable relations relative to the magnet  111 . In other words, the voice coil assembly  117  is movably attached to the transducer housing  120  comprising the flange  103  and the yoke  104 , such that it may move axially outwards from the transducer housing  120  along a path of excursion during various excited state(s), and return to rest in a position as illustrated in  FIGS. 4A and 4B . 
     Moving further to  FIGS. 12-13 , other embodiments of the present invention further comprises an external housing  200  utilized for mounting the surface acoustic transducer  100  described above onto a surface or material, such as an interior cabin, bulkhead, and/or window panel of an aircraft. As indicated in  FIG. 12 , the external housing  200  may at least partially enclose the surface acoustic transducer  100 , in order to retain the transducer  100  therein and attach the same to a surface  75  via at least one mounting bracket, such as mounting bracket(s)  203  and/or  203 ′. When mounted or installed therein, the transducer  100  maintains a center alignment with the external housing  200 , and a center line screw  206  may be utilized to stabilize and affix the transducer  100  within the external housing  200 , such that the screw may cooperatively enter a center aperture  205  of an excursion cover  201  forming on a proximal portion of the external housing  200 , and reach distally down towards the yoke  104  attached to or forming the distal portion of the transducer housing  120 , and therefore serving as a structural securing mechanism. 
     Drawing attention to additional details in  FIGS. 13A-13C , the external housing  200  generally comprises a retaining wall  202 , at least one mounting bracket  203  and/or  203 ′, and an excursion cover  201 . The retaining wall  202  is preferably formed of a cylindrical shape and rigid composition such as to protect the interior thereof from external forces, such as when a person leans against a surface or interior cabin of an aircraft that the surface transducer  100  and external housing  200  are attached to. As such, the retaining wall  202  may further be attached to, or formed with, at least one mounting bracket  203  and/or  203 ′, comprising at least one aperture  204  on each bracket so as to secure the external housing  200  to a substantially flat surface by conventional means, such as nails or screws, or adhesive. In one embodiment, the mounting brackets or alternatively, their respective apertures  204 , may be optional as the external housing  200  may be secured to a surface via adhesives. In another embodiment, detailed in  FIG. 16 , the mounting brackets  203 ,  203 ′ or alternatively, their respective apertures  204  may allow mechanical reinforcement of bonding from adhesive  50  as adhesive flows into the aperture  204  and onto the opposing surface  75  creating an enlarged area  52 , exterior of the apertures  204  which may have a general “mushroom” shape when dry resulting in additional mechanical fastening strength. In particular, based upon the configuration of the present transducer assembly, the use of an adhesive  50  bond may be optimal in certain embodiments. Moreover, if desired, to provide additional strength, in addition to the normal bonding strength based upon surface to surface contact between the mounting brackets  203 ,  203 ′ and the surface  75 , a mechanical bond is also created by the enlarged area  52  acting much like the head of a rivet or screw to hold down the mounting brackets  203 ,  203 ′ onto the surface  75 . It is noted that although in the preferred embodiment the mounting brackets  203 ,  203 ′ are being mounted to the same underlying surface  75  as the coupler ring  101 , in alternate embodiments they may be mounted to different, attached or isolated surfaces. 
     The excursion cover  201  is formed on or attached to the retaining wall  202  via a plurality of contact portions  207 . In the embodiment illustrated in  FIG. 13B , the excursion cover  201  comprises a spiral or helix structure having three contact portions  207 , such as to provide a degree of protection to the transducer  100  housed therein, yet at the same time allow for the excursion of the transducer  100 , and more specifically its primary assembly and/or voice coil assembly outwardly. In other words, the structural configuration, composition, contact portions, and/or combinations therefore, support the malleability of the excursion cover  201 , which may also move outwardly in response to the transducer  100  entering excited state(s), and therefore help support a richer and more vibrant sound rather than dampening it. Of course, in other embodiments, it should be understood that two or more contact portions  207 , in addition to various compositional and physical characteristics of the excursion cover  201 , may be used, depending on the degree of malleability or rigidness required. 
     In one embodiment, the external housing  200  may be formed from injection molding as an injection molding resin including but not limited to polypropylene, polyethylene, ABS, polycarbonate, glass reinforced molding resin, injection molding resin with flame retardant. In other embodiments, the external housing  200  may be formed from steel stamping, and/or other appropriate materials known to those skilled in the art. 
     Drawing attention to back to  FIGS. 5-11 , each element of the transducer  100  of the present invention is further shown separately in perspective views. 
       FIG. 5  illustrates a coupler ring  101  of the present invention. The material composition of the coupler ring  101  may comprise polycarbonate, plastic, and/or other appropriate materials or combinations thereof. The coupler ring  101  may be intended to be disposed against an external surface, such as an aircraft&#39;s interior cabin, in order to transfer the vibrations from the primary assembly for the production of sound. 
       FIG. 6  illustrates a voice coil assembly  117  comprising a voice coil former  115  attached to the coupler ring  101 . The voice coil former  115  is preferably formed of aluminum, but may also utilize other appropriate materials. The voice coil former  115  may comprise a thickness of approximately 0.05 mm in a preferred embodiment of the present invention. A voice coil wire  116  may be wound in surrounding relation to the voice coil former  115 . In a preferred embodiment, the voice coil former  115  and wire  116  may comprise a diameter of 20-28 mm. In another embodiment, a single layer winding of the voice coil wire may result in a diameter of 26.5 mm. In another embodiment, a two layer winding may result in a diameter of 26.8 mm. The voice coil wire  116  is preferably formed of copper, but may also utilize other appropriate materials. In at least one embodiment of the present invention, the surface acoustic transducer  100  comprises a voice coil having a wattage of between 20 W to 30 W. In a preferred embodiment, the voice coil will have a wattage of 25 W. 
       FIG. 7  illustrates a magnet  111  of the present invention for providing a magnetic field to the voice coil assembly  117  and voice coil wire  116  thereof. The magnet  111  may comprise a neodymium iron boron (NdFeB) N42H magnet in at least one embodiment. Of course, other grades of NdFeB ranging from N24 to N52 may be used in other various embodiments of the present invention. Various other materials may include Alnico (AlNiCo), Samarium Cobalt (SmCo), as well as other known and appropriate rare-earth magnet or permanent magnets may be utilized. In a preferred embodiment, the magnet comprises a substantially cylindrical and/or disc shape or profile. 
       FIG. 8  illustrates a flange  103  of the present invention, and structured to retain a terminal attachment  105  for receiving electrical input from an external source. The material composition of the flange  103  may comprise a polycarbonate or plastic compound and/or mixture. 
       FIG. 9  illustrates a spider  102  of the present invention, and structured and cooperatively disposed to dampen or at least partially impede the movement of the voice coil assembly  117 . The material composition of the spider  102  may comprise a resin dipped cloth or fabric. However, other flexible materials and/or coatings known to those skilled in the art may also be used in order to accomplish a desired mechanical compliance (or the inverse of stiffness). The preferred mechanical compliance of the spider  102  is 0.23 millimeters per Newton (mm/n), offering a greater excursion range (less damping) than other transducers known in the art. A range of between 0.2 mm/N to 0.3 mm/N may also be used in various other embodiments. 
       FIG. 10  illustrates a top shunt plate  112  of the present invention, preferably coupled to the magnet  111  of the present invention. The material composition of the top shunt plate  112  may comprise a mild steel or low carbon steel such as EN1A, but may also comprise other appropriate metals known to those skilled in the art. 
       FIG. 11  illustrates a yoke  104  of the present invention, forming a distal end of the transducer housing  120 . As shown, the yoke may comprise a plurality of taps for the insertion of screws such as M4 screws or other screws for affixing and stabilizing the transducer housing  120 . The yoke  104  may similarly comprise a mild steel or low carbon steel such as EN1A, but may also comprise other appropriate metals known to those skilled in the art. 
     Further embodiments of the present invention are directed to systems and methods for using the surface acoustic transducer of the present invention, or like transducers, in order to produce quality sound and/or for noise cancelling applications. 
     In at least one system embodiment of the present invention, a plurality of surface acoustic transducers, such as the transducer  100  described above, may be attached a panel or surface such as a window, a wall, or an interior cabin of a vehicle. Specifically, one embodiment may be directed to an aircraft window panel having a plurality of surface acoustic transducers disposed thereon and hidden beneath the bulkhead or cabin wall within an aircraft. 
     At least one embodiment of the panel may be directed to noise cancelling operations for reducing the net vibration of the window and/or various panels or surfaces in proximity thereof. As such, a plurality of surface transducers may be mounted to a surface of a window and/or window panel underneath a bulkhead or other non-visible area internal to an aircraft cabin, as external noise generally resonates loudest at the windows. Ideally, the transducers are mounted along a perimeter of the window, so as to avoid obstruction of the view, such as general illustrated in  FIGS. 14 and 15  as systems  300  and  400  respectively. These Figures and systems are example embodiments of various configurations of transducer  100  placement via external housing  200 , and are by no means limiting. In other words, any number of transducers  100  may be mounted via housing  200  on one or more external and/or internal structural window panels, dust covers, chromatic and/or electrochromatic panels, glass, or other transparent materials, as well as nontransparent bulkhead connections, that may act as points of entry of external sound such as engine noise into an interior cabin of an aircraft or other vehicle. 
     The panel may further comprise various components configured for active noise control (ANC) or noise cancellation, such as to cause the plurality of transducers to emit an anti-noise signal in order to counter the noise source, and installed or disposed within an interior or non-visible portion of an aircraft cabin in proximity to the window panels whether by wired or wireless communication to each of the transducers  100 . For example, the panel may comprise a power source, a receiver module, a processing unit, and at least one transducer. The receiver module may be mounted within an interior or exterior of the panel, or may be mounted remotely and be communicably connected to the panel and the processing unit. The receiver module may comprise a microphone, and is configured to receive sound signals or noise signals to relay to the processing unit. The processing unit is configured to receive the noise signals and produce an anti-noise signal, which may comprise a sound signal with the same amplitude but with an inverted phase relative to the noise signal (or antiphase). This anti-noise signal is then transmitted to the at least one transducer to be reproduced at the panel, therefore canceling any noises received by the receiver module, such as external engine noise. 
     Other embodiments of the present invention may be directed to methods for sound processing as directed to a surface acoustic transducer, such as transducer  100  described above. As discussed, one known limitation in the art is the inadequacy of bass frequencies of surface transducers, primarily due to their mechanical limitations, i.e. the lack of adequate mechanical excursion. To overcome this limitation, and in order to provide a richer bass sound, a method of the present invention contemplates first selecting the various points at which to limit the peak decibels of a sound signal. Next, the sound is processed at these points, such that the amplitude of the sound signal is reduced and its frequency proportionately enhanced. This, and other sound processing methodology may be accomplished pursuant to the Applicant&#39;s digital signal processing methods as recited in U.S. Pat. No. 8,160,274, which is hereby incorporated by reference in its entirety. 
     It should be understood that the above steps may be conducted exclusively or nonexclusively and in any order. Further, the physical devices recited in the methods may comprise any apparatus and/or systems described within this document or known to those skilled in the art. 
     Since many modifications, variations and changes in detail can be made to the described preferred embodiment of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents. 
     Now that the invention has been described,