Abstract:
A bone-conduction speaker unit including a resilient metallic voice screen having a plurality of substantially equally spaced locking elements around a periphery thereof, coupling with a yoke supporting a centered magnet within a magnetic ring, the voice screen and yoke being above a metal cover of a housing to which a bone-conduction speaker so formed is affixed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    A Provisional Patent Application covering the invention described herein was filed on Jul. 15, 2014, and assigned Ser. No. 62/024489. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Research and development of this invention and Application have not been federally sponsored and no rights are given under any Federal Program. 
     
    
     REFERENCE TO A MICROFICHE APPENDIX 
       [0003]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    This invention relates to bone conduction-speakers, in general, and to a bone-conduction speaker-unit particularly employable for earbud speakers. 
         [0006]    2. Description of the Related Art 
         [0007]    As is known, bone-conduction speakers function on a principle where the speaker typically includes a transducer to receive an electrical signal (such as an audio signal) and to generate a controlled vibration in response. When worn, the transducer transmits the vibration to the bones of the wearer&#39;s skull—from which, it is transmitted to the wearer&#39;s inner ear. The bone conduction then enables sound to be transmitted this way to the wearer&#39;s inner ear by vibration, rather than by way of sound waves that travel through the air to enter the wearer&#39;s outer ear. 
         [0008]    Bone-conduction speaker designs, however, typically suffer from somewhat less than optimal sound richness quality, particularly at the low and mid frequency ranges; they also tend to exhibit noticeable amounts of decreased durability in use. Experience has shown these undesirable features become more pronounced, furthermore, as the wearer ambulates in tending to move about, instead of his/her just sitting in place. Testings have shown that this is at least partially because of the manners by which the innards of the bone-conduction speaker have been stabilized—most often with bonding adhesive techniques. 
       OBJECTS OF THE PRESENT INVENTION 
       [0009]    It is an object of the present invention, therefore, to provide a bone-conduction speaker which provides a more robust sound and, at the same time, establishes an increased securement of its component parts to its vibration actuator during wearer movements about. 
       SUMMARY OF THE INVENTION 
       [0010]    As will become clear from the following description, the bone-conduction speaker of the invention essentially employs internal and external magnets along with a novel voice screen actuator to resonate in creating the controlled vibrations for the inner ear bones. As will also become clear, this voice screen is of a resilient metallic composition that includes a plurality of substantially equally spaced locking elements around a periphery thereof, coupling with a yoke to support the internal magnets of the speaker within an external magnetic ring. As will be described, two separate embodiments of the invention satisfy the above objectives—each utilizing a precious metal voice screen fabrication of titanium or tungsten, or similar such non-brittle, resilient materials. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and other features of the invention will be more clearly understood from a consideration of the following description, taken in connection with the accompanying Drawings in which: 
           [0012]      FIG. 1  is a longitudinal sectional view illustrating the manner by which a first embodiment of the bone-conduction speaker unit of the invention is incorporated within a housing; 
           [0013]      FIG. 2  is a longitudinal sectional view of a second embodiment of a bone-conduction speaker unit according to the invention, similarly built into the housing; and 
           [0014]      FIG. 3  is a plan view of the voice screen used in the bone-conduction speaker units of the  FIG. 1  and  FIG. 2  embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Referring to  FIG. 3 , the resilient, non-brittle metallic voice screen  2  of the bone-conduction speaker unit has three leaf spring prong portions  30 , each extending along a spiral curve between central and peripheral portions  31 ,  32 . Each of the leaf spring prong portions  30  is formed by inner and outer curves  33 ,  34  substantially parallel to the curve of the periphery shown in circumferential layout. An elongated hole  35  is centrally located with respect to the periphery  32  of the voice screen  2 , with each of the leaf spring prong portions  30  terminating in substantially a point  36 . As will be understood, the voice screen  2  essentially constitutes a single piece of preferably titanium or tungsten material of a circular-arcuate spiral, whose individual “prongs” would be vibrating in generating the resultant “sounds”. (Other types of precious metal materials similarly may instead be used for the screen.) 
         [0016]    The bone-conduction speaker unit of the  FIG. 1  embodiment comprises a housing  1  defined by a metal cover  10  and a printed circuit board  11  which mechanically supports, and electrically converts, the electronic components using conductive track pads and other features etched from copper sheets laminated into a non-conductive substrate in conventional manner. A yoke  3  having a centered magnet  4  within a steel plate  5  is disposed between an external magnetic ring  6  encircling a voice coil  9 . Such voice coil  9 , in turn, is disposed between a steel ring  7  and an upper cover  8 . In typical usage for an in-ear headphone, the speaker housing  1  couples with a first earbud housing, while the printed circuit board  11  couples with a second earbud housing at one end, for example, of an electrical cord connecting headset. With the magnet  4  and the external magnetic ring  6 , with the voice screen  2  as described, and with the elongated hole  35  of the voice screen  2  in alignment to receive a lower extending section  60  of the yoke  3 , enriched sounds at the low and mid frequency ranges are produced as compared to the more conventional constructions employing a spring vibration in producing an auditory input to the inner ear. 
         [0017]    While the embodiments of  FIGS. 1 and 2  each produce enhanced sound reproduction, their constructions differ insofar as the securement of the operative inner parts of the bone-conduction speaker unit are concerned. In each of the embodiments of  FIGS. 1 and 2 , inside side wall surfaces of the housing  1  are notched at  50 ,  51  in receiving curved edges  52 ,  53  of the metal cover  10 . In the embodiment of  FIG. 1  on the one hand, the yoke  3  is fabricated of a  3  level “step” construction, with the smallest section  60  configured to press fit within the elongated hole  35  of the voice screen  2 . Equally spaced, opposing edge sections of the periphery  32  of the voice screen  2  are likewise fitted to be held by the notches  50 ,  51  of the housing walls in securing with the upwardly curved edges  52 ,  53  of the cover  10 , yielding a downwardly curved voice screen lock as shown at  70 . 
         [0018]    In the  FIG. 2  embodiment of the invention, on the other hand, the yoke  3  is configured as a substantially flat plate, and a rivet  12  extends upward through the metal cover  10  to secure with the elongated hole  35  of the voice screen  2 —whose equally spaced, opposing sections of the periphery are then secured in place as at  71 ,  72  under the yoke  3  in giving an upwardly curved look to the thereby locked voice screen, as at  73 . 
         [0019]    Both arrangements of  FIGS. 1 and 2  thereby mechanically capture and secure with the voice screen  2  not only physically, but as ensuring that only the inputted electrical signal causes the screen  2  and its spring prong portions  30  to vibrate; and not any motion of the bone-conduction speaker unit components as a result of a wearer&#39;s moving about while wearing the bone-conduction speaker. As the mechanical pressure applied in holding the voice screen in position changes the securement without any adhesive bonding, the common tendency for the adhesion to lessen over time will be understood to be substantially obviated. In effect, the constructions of the  FIGS. 1 and 2  embodiments produce equally spaced locking elements around the periphery of the voice screen in fixing the bone-conduction speaker so formed by its associated components. 
         [0020]    While there have been described what are considered to be preferred embodiments of the present invention, it will be readily appreciated by those skilled in the art that modifications may be made without departing from the scope of the teachings herein. Different compositions of materials can be used in constructing the resilient, metallic non-brittle construction of the voice screen besides titanium and tungsten, consistent with the advantages provided by the utilization of precious metals in their fabrications. And, likewise, different configurations for the voice screen may be employed as well as the circular configuration of  FIG. 3  in providing an increased richness of sound and increased stability of operation. For at least such reasons, therefore, resort should be had to the claims appended hereto for a true understanding of the scope of the invention.