BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description, they serve to explain the principles of the invention. In the drawings:
FIG. 1 is a cross-sectional view of a typical prior art balanced armature acoustic transducer in its application as either a microphone or a speaker;
FIG. 2 is a graphical representation comparing the frequency responses or spectra for prior art transducers to an ideal condition for a transducer used a speaker;
FIG. 3 is a perspective view showing the exterior of one exemplary embodiment illustrating some of the principles of the present invention in the form of a single diaphragm receiver;
FIG. 3
a is a cross-sectional view of the exemplary embodiment of FIG. 3;
FIG. 3
b is an exploded view of the exemplary embodiment of FIG. 3;
FIG. 3
c is a perspective view of an integrated armature/diaphragm used in the exemplary embodiment of FIG. 3;
FIG. 4 is a perspective view showing the exterior surface of another exemplary embodiment illustrating some of the principles of the present invention in the form of a “double bent armature” wherein the armature is doubled-back on itself;
FIG. 4
a is a cross-sectional view of the exemplary embodiment of FIG. 4;
FIG. 4
b is an exploded view of the exemplary embodiment of FIG. 4;
FIG. 4
c is a perspective view of the integrated armature/diaphragm used in the exemplary embodiment of FIG. 4;
FIG. 5 is an exploded view of illustrating the exterior view a further exemplary embodiment utilizing some of the principles of the present invention in the form of a “dual double bent armature having axial aligned sound ports;”
FIG. 5
a is a perspective view of illustrating the exterior view a further exemplary embodiment utilizing some of the principles of the present invention in the form of a “dual double bent armature having axial aligned sound ports;”
FIG. 5
b is a cross-sectional view of the exemplary embodiment of FIG. 5a illustrating some of the principles of the present invention in the form of a dual diaphragm receiver wherein the armature elements are doubled-back on themselves and the central structure is common to both balanced diaphragm actions;
FIG. 5
c is a perspective view of illustrating the exterior view a further exemplary embodiment utilizing some of the principles of the present invention in the form of a “dual double bent armature having radial aligned sound ports;”
FIG. 5
d is a cross-sectional view of the exemplary embodiment of FIG. 5c illustrating some of the principles of the present invention in the form of a dual diaphragm receiver wherein the armature elements are doubled-back on themselves and the central structure is common to both balanced diaphragm actions; and
FIG. 6 is an exploded view of another exemplary embodiment illustrating some of the principles of the present invention in the form of a “solenoidal armature” wherein the armature coil is perpendicular to the armature diaphragm.
FIG. 6
a is a perspective view showing the exterior surface of a “solenoidal armature” wherein the armature coil is perpendicular to the armature diaphragm and the sound exit conduits are axially aligned.
FIG. 6
b is a cross-sectional view of the exemplary embodiment of FIG. 6a illustrating some of the principles of the present invention in the form of a “solenoidal armature” wherein the armature coil is perpendicular to the armature diaphragm and the sound exit conduits are axially aligned.
FIG. 6
c is a perspective view showing the exterior surface of a “solenoidal armature” wherein the armature coil is perpendicular to the armature diaphragm and the sound exit conduits are radial aligned.
FIG. 6
d is a cross-sectional view of the exemplary embodiment of FIG. 6c illustrating some of the principles of the present invention in the form of a “solenoidal armature” wherein the armature coil is perpendicular to the armature diaphragm and the sound exit conduits are radial aligned.
Reference will now be made in detail to certain exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The specifically illustrated exemplary embodiments relate to an acoustic transducer that minimizes frictional and other mechanical losses. When used in connection with a balanced armature type of transducer, these exemplary embodiments advantageously eliminate a connector element by integrating the armature and diaphragm. Acoustic conduits, specifically shown in the exemplary embodiments as holes in the poles of the magnets of the transducer, provide acoustic coupling between the integrated armature/diaphragm and the external sound environment.
Certain aspects of the illustrated exemplary embodiments are best appreciated by a comparison with conventional balanced armature type transducers of a type similar to these exemplary embodiments illustrated. Referring specifically now to the drawings, FIG. 1 is a cross sectional depiction of a conventional state of the art balanced armature acoustic transducer 100. This particular illustrated prior art transducer 100 includes a permanent magnet 114 with having a “north” pole 116 and a “south” pole 118 and an air gap 112 located between the poles 116 and 118. The magnet 114 produces a magnetic field in an air gap 112. In this conventional prior art transducer, a free end of a beam 120 extends into the air gap 112. The beam 120 is made of magnetically permeable material and is supported in a cantilever fashion. A mechanical bond between the beam 120 and an internal surface of the housing 100 is provided at location 110 to secure a fixed end of the beam 120 such that the free end of the beam is centered between poles 116 and 118 in the air gap 112. An electrical coil 130 created from turns of insulated conductor 129 is wound around a portion of beam 120 such that an electric solenoid is created whose beam 120 “core” is a dipole magnet. One end of a connecting rod 140 is connected to the free end of beam 120 through a joint 143. The other end of the connecting rod 140 is connected to a sound-producing surface 150 through a joint 145. The sound producing surface 150 has a compliant supporting peripheral portion or “surround” 152 at its outermost edge, and this outermost edge forms an acoustic seal along its periphery as it attaches to a supporting structure 151, which supporting structure 151 extends inwardly from an interior surface of the structural housing 100 and forms a floor of an acoustic chamber structure 160. The acoustic chamber structure 160 has an output port 165 to which a conduit or other acoustic conveyance (not shown) can be attached to direct sound energy to the external acoustic environment, typically a wearer's outer ear.
FIG. 2 depicts a comparative frequency response plot between representative of the acoustic output of a conventional state of the art balanced speaker, such as the speaker illustrated in FIG. 1, and the response of an ideal receiver in response to a constant input of electrical current. The abscissa of the plot depicted in FIG. 2 is logarithmic frequency, and the ordinate representing decibels of sound pressure level, also a logarithmic form of measure. The solid line represents the spectral plot 200 for a typical existing state of the art balanced diaphragm receiver, such as illustrated in FIG. 1. This solid line is comprised of a relatively flat zone 210, followed by a rising region 220, resulting in a first peak 230 occurring at approximately 1100 Hz, followed by its declining region 240, which reaches a trough 250 at approximately 1600 Hz, which is followed by a second peak at 260 at approximately 2200 Hz, and a continuum of repeated peaks and valleys in region 270 at the upper extent of the spectral plot. The frequently response of a conventional transducer is compared to that of an ideal receiver, which is depicted in the straight dashed spectral plot 280. The spectral plot of line 280 represents the theoretically flat response of an ideal receiver whose output in response to a constant input energy as a function of frequency would be a constant and uniform acoustical output as a function of frequency.
FIGS. 3, 3a and 3b show a first exemplary embodiment of the present invention in a form utilizing a “straight armature” receiver. In this exemplary embodiment, a transducer is enclosed within a structural housing 300 that encloses the transducer. The structural housing 300 contains a magnet 340 (see FIGS. 3a and 3b), which in this specifically illustrated embodiment has an annular configuration. A magnetic field is produced in an air gap or magnetic flux area 316 located between the opposite magnetic poles formed between an upper magnetic pole piece 380 and a lower pole piece 320. Exemplary suitable permeable ferro-magnetic materials from which pole pieces 380 and 320 might be made include the iron-based “High mu 80” (Carpenter Steel Corporation). In the exemplary form illustrated, an acoustic conduit is formed in upper pole piece 380 by piercing through the upper pole piece to form holes 382. The illustrated exemplary embodiment further includes correspondingly aligned holes 392 (see FIG. 3b) in upper case portion 390. These aligned holes form an acoustic path through which a fluid, such as air, maintains contiguous relationship with fluid present on the inside of pole piece 380 and the outside of upper case 390. The magnetic structure, exemplarily illustrated as an annular magnet 340 may be a permanent magnet or it may be an electromagnet built using well-known principles of winding a coil around a magnetically permeable form. As those skilled in the art will readily appreciate, if an electromagnet is used, an electric current is supplied to the coil to form a magnetic field.
As best illustrated in FIG. 3c, this exemplary embodiment includes a vibratable sound-producing member, specifically illustrated in this drawing figure as an armature that is integrated with a diaphragm. The illustrated armature/diaphragm 350 includes at least a portion of magnetically permeable material 358. The illustrated armature/diaphragm 350 also has a cantilevered geometry with a base that is rigidly affixed to a magnetic coil structure 360. The diaphragm forming “free” end of the armature/diaphragm 350 is such that the magnetic forces in the air gap 316 just balance the supporting forces. A sound-producing surface 352 is intimately affixed to the magnetically permeable material 358 so as to be integral with the armature structure 350. Compliance-producing surround 354 is also integrally disposed peripherally with sound producing surface 352 and is also continuously affixed to upper support ring 370 and lower support ring 330 on its flexible “surround” periphery 354. An electrical to magnetic coil 360 is wound around a portion 356 of the armature 350 at a position starting near its fixed end. Acoustic cavities 326 (see FIG. 3a) are formed within case structure 310 inside of lower pole 320 to as one form of acoustic tuning means. Case structure 310 further provides a structural support to the fixed end of the beam 320 as well as the annular magnet 340 and poles 320 and 380.
FIGS. 4, 4a and 4b show a second exemplary embodiment of the present invention in the form of a “double bent armature” receiver 400. In this exemplary embodiment, a magnetic field is produced in air gap 416 by an annular magnet 440, an upper magnetic pole piece 480 and a lower pole piece 420. Pole pieces 480 and 420 are made of a suitably permeable ferro-magnetic material such as “High mu 80” (Carpenter Steel Corporation), and upper pole piece 480 is configured with openings or holes 482 (see FIG. 4b) through which a fluid such as air maintains contiguous relationship with fluid present on the inside of pole piece 480 and its outside boundary. Similarly, opening(s) or hole(s) 422 (see FIG. 4b) in lower pole piece 420 provide a pathway through which fluid such as air maintains contiguous relationship with fluid below and above the pole piece 420. The openings 422 so may be continued as shown by other openings, as illustrated by 412, that extend through the bottom case 410. As specifically illustrated, the exemplary embodiment of FIG. 4 shows an annular magnet 440, which may be a permanent magnet or it may be an electromagnet built using well-known principles of winding a coil around a magnetically permeable form and supplying said coil with an electric current to form a magnetic field. The armature 450 (shown in greater detail in FIG. 4c) of this exemplary embodiment is comprised of at least a portion of magnetically permeable material 458. The illustrated armature 450 has a cantilevered geometry with a base 456 that is rigidly affixed to lower body structure 410 at mounting block 465. The armature 450 also includes a diaphragm forming “free” end configured and arranged so that the magnetic forces in the air gap 416 just balance the supporting forces. A sound-producing surface 452 is intimately affixed to the armature/diaphragm so as to be integral with the armature/diaphragm structure 450.
A compliance-producing surround 454 is also integrally disposed peripherally with sound producing surface 452 and is also continuously affixed to upper support ring 470 and lower support ring 430 on its flexible “surround” periphery 454. An electrical to magnetic coil 460 is wound around a portion 456 of the armature 450 at a position starting near its fixed end. Acoustic cavities shown as through gap 422 and hole(s) 424 are formed within case structure 410 inside of lower pole 420 to form acoustic tuning means in companion with which may, as shown by 412, or may not entirely proceed from the inner portion of lower pole 420 and through lower case 410 to the external environment. Case structure 410 further provides a structural support to the fixed end of the bent beam 456 through mounting block 465 (see FIG. 4b). Mounting block 465 provides support and concentric alignment for the annular magnet 440, magnetic pole pieces 420 and 480 and the support rings 430 and 470.
FIG. 5 illustrates, as an exploded view, a third exemplary embodiment of the present invention in the form of a “dual double bent armatures” receiver. FIGS. 5a and 5b show a first variation 500, and its cross-section 502 respectively, of the present embodiment having axially-aligned acoustic conduits 582 and 592 emerging from the top and bottom respectively of the device. FIGS. 5c and 5d show a second variation 501, and its cross-section 503 respectively, of the present embodiment having radial-aligned acoustic conduits 584 and 585 emerging from the side clamshell half 595 respectively of the device, and further combining into the single acoustic nosepiece conduit 599. In general terms, this particular exemplary embodiment depicts two complete electro-mechanical-to-acoustic transducing sections, an upper transducing section 504 and a lower transducing section 505, having similar, but not necessarily identical mechanical to acoustic elements. As most clearly seen in FIG. 5, these units share a common outer supporting structure comprised of two “clamshell style” halves, 595 and 596 respectively, and a common electrical winding in the form of an excitation coil 530. Excitation coil 530 forms a continuous magnetic solenoid with upper diaphragm armature 550 and also with lower diaphragm armature 551 (See FIG. 5). Both of these diaphragm armatures 550 and 551 in this exemplary embodiment are similar in composition to the single armature 450 in the exemplary embodiment illustrated in FIG. 4, and may be comprised of the same detail parts as delineated in connection with that earlier described exemplary embodiment. In the form of the invention represented by the present exemplary embodiment (of FIGS. 5, 5a, 5b, 5c, and 5d) the upper diaphragm armature 550 may or may not differ from lower diaphragm armature 551 as is depicted, depending upon the acoustical characteristics desired in any particular variation of the present embodiment. For instance, the upper diaphragm/armature 550 may be more stiffly supported and less massive than lower diaphragm armature 551, and the diameters of the diaphragm armatures, their magnetic permeability, and material composition may be identical or different. In the general exploded representation of the embodiment of FIG. 5, the upper magnetic section of the receiver of this exemplary embodiment is comprised of an uppermost pole piece 580 of magnetically permeable material having aforementioned open acoustic conduits 582 traversing through its thickness, an upper magnetic source ring 540, an upper outer side spacer support ring 572 and an upper inner side spacer ring 570 that each engage the surfaces on the periphery of the diaphragm portion of diaphragm armature 550, and an innermost pole piece 520, which has at least one pole gap 522, a singular feature being required for the passage of diaphragm armature 550 on its way to excitation coil 530, and, optionally, one or more auxiliary passages 524. Similarly, the lower magnetic section of the receiver of this exemplary embodiment is comprised of a lowermost pole piece 581 of magnetically permeable material having aforementioned open acoustic conduits 583 traversing through its thickness, a lower magnetic source ring 541, a lower inner side spacer support ring 571 and a lower outerside spacer ring 573 that each engage the surfaces on the periphery of the diaphragm portion of diaphragm armature 551, and an innermost pole piece 521, which has at least one pole gap 523, a singular feature being required for the passage of diaphragm armature 551 on its way to common excitation coil 530 and, optionally, one or more auxiliary passages 525. Clamshell halves 595 and 596, when assembled as a continuous cylinder, provide physical encasement of the motor and sound producing parts in a stacked concentric fashion. Shelf detail 597 may have one or more conduits 598 as shown in the inner part of clamshell half 596, and a similar structural element may or may not be present in the mating clamshell half 595.
FIG. 6 illustrates, as an exploded view, a fourth exemplary embodiment of the present invention in the form of a “solenoid induction armature” receiver. FIGS. 6a and 6b show a first variation 600, and its cross-section 602 respectively, of the present embodiment having axially-aligned acoustic conduits 682 emerging from the device and one or more auxiliary secondary “tuning” acoustic conduits 624 emerging through other elements. FIGS. 6c and 6d show a second variation 601, and its cross-section 603 respectively, of the present embodiment a having radial-aligned acoustic conduit 684 emerging from the side of the device, and further continuing acoustic nosepiece conduit 699. Appropriate gap features 671 and 673 are provided in this variation of the embodiment in companion with passages 644 and 645 that complete the unobstructed sound conduit connecting the sound-generating surface with the nosepiece conduit 699. In general terms, this exemplary embodiment as most generally depicted in exploded view 600 shows the structure of a device which, while retaining the primary feature of a sound generating surface 650 contained within the static magnetic producing features (upper pole piece 680, magnet 640, and lower pole piece 620) separates the magnetic flux concentration structure as core 680 with central pole 685 that supports the coil 680, from the sound generating surface 650. An alignment features such as step 628 on lower pole piece 620 is shown in alignment relation with the outer margin of pole piece 680, and an outer step 626 is shown in alignment with magnet 640. A magnetic air gap 625 may be provided between lower pole piece 620 and magnetic core 680. Notwithstanding the geometric separation of these elements (the variable magnetic portion of the armature (630, 680 and 685 collectively) from the sound producing surface 650, the elements together constitute a single physically (magnetically combined) armature/diaphragm structure.
The foregoing description of preferred embodiments of the invention has been presented for purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments were chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
Patent Application
20080049967
