Патент USA US2532743код для вставки
Dec. 5, 1950 R. R. STEVENS MICROPHONE WITH OPPOSITE ELECTRODES BEING OF‘ VARYING AND CONSTANT CURVATURE Filed Oct. 31, 1947 35 2,532,741 v//////. i lNl/ENTOR By R. R. STEVENS A T TOR/VEY 2,532,741 Patented Dec. 5, 1950 PATENT" OFFICE 2532,7411 MICROPHONE. WITH' OPPOSITE. ELEC-v TRTODES, BEING. OF" VARYINGQ AND‘ CONSTANT"CURYATURE" Ralplr. m". Stevens; . Ghathamg- N2 J1, assi'gnorz to; Bellu'l‘elenhonerhabcratories;,Incorpprated,,New YnrkaNnY‘g ,a.-_ corporation of New York Applicatiomactober '31, 1943“,v Sélfiit-IKNO: 783E239‘; 83-:Claims. '(Cl. 1789-122‘) 1, This 1‘ invention’ relates-1 to» telephone. transmit’ terse and“ more“ particularl3r~= to" carhonv» granule‘ type transmitter‘ units- especially suit‘ablefor use: in hand telephones; One general object of'this ‘invention is-‘tok-img prove the operating- charact‘eris'tics -of-" telephone“ ’ transmitters of" the~vv carbon“ granule’ type; More speci?cally; onerobject' of‘v this? invention" is to. obtainsubstantiallyuniform‘ performancerof such‘ sti?eninglcorrugations'or'?utes I4 and: connected; to the» peripheral; portion: r2; by " an. annular" cor; rugated or: trough‘ portion l5? whichiis sufficiently ?exible: to allow: lbodilyi vibration. of i the: central ' part l3. The diaphragm, together withamois turei-prootifmembrane. l6“ and aimultt-apertured protectivezcoven'orl'screen I1; is. secured to; frame by. a. clamping ‘band l8; Mountedlhythe diaphragmaand .v-ibratilethere transmittersv for "a wide’ variety-"ofvv positions in" 10,1. with? is an electrode IQ of 'para-boloid'all' form and‘ havingT a flange 281' and’ tabsv 2!‘ between which which they'ma'y'beheld‘during‘use; the' inner" edge- portion: of," the' diaphragm is In" one-illustrative embodiment" of'thi‘s invent gripped; Al'sosecured‘ between the ?ange and’ tlon, a transmitter-unit“of‘the-*typerand" general" tabseare' the~=innerv portions of" a‘, metallic. spider‘ construction disclosediiir \Patenti 22042822 "grant ‘= 22' and'ani annular; ?exible closure member 23; ed‘ June“ 2,- 1936‘ to ‘ Artli‘urx-Ff Bennett " and W11; for example of silk. The arms" of the’ spider, liam L. Tu?nell comprisesa'pair'o? coaxial'idi‘shed electrodes? and“ associated’ elements" huun'diirgv a, carbon" granule chamber; one of‘ the:v electrodes being ?xed.’ and‘ the-other being-coupled“ to a diaphragm" to vibrate therewith. ' In" accordancewithv one' feature ‘.Of inven tion; the surface‘of' one-of the electrodes‘ is a. surface‘ of‘revolution' the" generat'rix "of "which- is: which serves-res alead in conductor tothe elec trode--\ l9, extend-toand‘ contact an inner, annu lar-?ange» 24’on'theioundation member or frame 20: The outer portion of the closure member 23 is held between a pair of insulating'rings 25' and‘26 withirrthe cylindricaliiportion‘l‘ H 0f“the> founda than having, a generatrix-of1v constant. curvature. The‘ two surfaces’are coaxial” and "in- ‘j uxtaposition and because of the di?erencejn' the con?‘gurae tions, of these- surfaces the gap‘ therebetween tion mem’o'er; the’ring 26"being seated upon‘ an insulatingspacer 2-1’ which in- turn bears against the spider arms: A ?xed‘ electrode-is mounted‘ upon the ring‘ 25' and comprises‘ an annular ?ange 28' seated‘ on'this ring, and’av central: domed part having“ a hemispherical i‘ surface 29 in juxtaposition to- and‘ which the unitmaybeheldan-optimum or sub ?xed’ electrode is‘ provided with" an aperture 30 of" continuously -' varying curvature and‘v the" sur face" of'v the other: electrode also is‘ one' of'revolu varies continuously‘ so that for each position in ' ' coaxial with the paraboloidal electrode I91 stantially optimum current path between the two>electrodesobtains ' Alsoibecause" of‘ the dif ference, the spacing between the-two: electrodes‘ may be madez quite‘ small‘ whereby‘v improved modulation is obtained. ' The invention and the above-noted and. other: features thereofwill'be- understood; more. clearly. and‘ fully; from the following detailed description; with: referenceto the accompanying drawing-in, which‘? Fig.‘ Us a side'view insectionofla transmitter; unit'illustrative of‘one embodimentlof this ,inven'-~ tion;v and‘ ' Fig. 2 is a fragmentary sectional view illus trating a modi?cation of the unit shown in Fig. 1. Referring now to the drawing, the transmitter unit illustrated in Fig. 1 comprises an annular, The" through‘ which a-' ?lling" of ‘ carbon granules“ 31" is. introduced into the chamber bounded by; the electrode. l9‘; closure 23-,1ringi25‘ and‘ surface‘ 29. " A‘capor-cover-Mf'crimped over‘ the ?xed elec troclev cl‘osesthe- aperture ‘ 3 0." The" ?xed‘; electrode. and; rings. 25v and 26. are securely-held‘ in position in pile-up relation and" againstLthet'?‘ange' 24 by, an annular clamping band 33‘. one“ edge of which bears against an insulating? disc’ 34 seated‘ upon the electrode ?ange 28.‘. I _ It: will‘ be. noted‘ that‘ because of the - difference in the forms of‘th'e juxtaposed‘ surfaces ofthe 45 two electrodes, the spacing between these sur— faces is continuously changing; speci?cally, in the construction illustrated, this spacing ?rst increases, passes through a maximum, then de creases in the direction toward the diaphragm. metallic foundation member or frame l0 having a cylindrical portion ll of reduced diameter and 50 The continuous change in curvature of the vibra tile electrode surface, it has been found, sub having also a plane face against which the annu stantially minimizes variations in the perform lar peripheral portion 12 of a diaphragm is ance of the unit with changes in position in seated. The diaphragm, which may be formed which the unit is held during use thereof. That in one piece of light weight metal, includes a central frusto-conical part I3 provided with 65 is, the operating characteristics of the unit are 2,532,741 3 4 substantially independent of the position of the posed, coaxial and dished in the same direction, unit. Furthermore, the difference in the con?gura tions of the juxtaposed electrode surfaces allows one of said portions having a constant curvature and the other of said portions having a locus of close spacing of these electrodes and conse quently high modulation, without packing of the 5 continuously changing curvature, means for vibrating one of said electrodes relatively to the other thereof, means including said electrodes carbon granules. bounding a chamber of inner surface including The exact con?guration of the paraboloidal said portions and comminuted resistance-vary surface of the electrode I9 is of some moment. ing material in the chamber. Speci?cally, the generatrix of the surface is of 10 4. A telephone transmitter comprising a ?rst the form given by the equation X2=ky, where electrode having a concave dished portion, a X is the coordinate normal to the common axis second electrode having a convex surface extend~ of the two electrodes, y is the coordinate parallel ing toward and coaxial with said dished portion, to this axis, and k is a constant. Values of 7c be tween 0.0563 and 0.169 have been found satis factory. diaphragm means coupled to the second elec— 15 trode for vibrating it relatively to the first elec trode, said surface and the concave face of said portion being shaped in accordance with differ ent geometrical formulae having di?erent points The embodiment of this invention illustrated in Fig. 2 is similar to that shown in Fig. 1 and heretofore described. However, in the ‘embodi ment shown in the former ?gure, the surface 20 face and said face varying continuously there 35 of the ?xed electrode‘is frusto-conical. One slope which was found suitable for the generatrix over in any phase of vibration of the second elec trode, means including said surface and said of this surface was of the order of 45 degrees with reference to the common axis of the two electrodes. sistance-varying material in the chamber. Although speci?c embodiments of the inven tion have been shown and described, it will be understood that they are but illustrative and , of origin to provide a spacing between said sur face bounding a chamber and comminuted re 5. A telephone transmitter in accordance with claim 4 wherein'said surface is paraboloidal and said face is substantially hemispherical. '6. A telephone transmitter in accordance with that various modi?cations may be made therein claim 5 wherein the generatrix of said surface is without departing from the scope and spirit of 30 of the form X2- : ky, where y is the coordinate this invention as de?ned in the appended claims. parallel to the common axis of said face and sur For example, although in the embodiments illus face, .,X is the other coordinate and k is a con trated the entire convex surface of the vibratile ~ stant between about 0.0563 and 0.169. electrode is paraboloidal, a portion thereof ad 7. A telephone transmitter in accordance with jacent the ?ange 20 may be cylindrical and the 35 claim 4 wherein said face is frusto-conical and remainder paraboloidal. ‘ ' - said surface is paraboloidal. . 1 Reference is made of the application Serial No. 783,324 ?led October 31, 1947, of Herbert W. 8. A- telephone transmitter comprising a pair of electrodes bounded each by a surface includ Bryant wherein a related invention is disclosed ing a dished portion, the dished portions of the and claimed. 40 two surfaces facing each other and dished in the What is claimed is: ‘ same direction along a common axis of revolution 1. A telephone transmitter including a pair of but of diiierently varying steepness with respect electrodes having opposed surfaces bounding a thereto wherefore the spacing between said por chamber, comminuted resistance-varying ma tions is a maximum over an intermediate zone terial in the chamber and means for vibrating 45 between the portions and decreases therefrom one of the electrodes relatively to the other, the toward each electrode, means including said por opposed electrodes being respectively convex and tions bounding a chamber, comminuted resist concave toward the other and shaped in accord ance-varying material in the chamber and means ance with different geometrical formulae having for vibrating one of said electrodes. different points of origin to provide a spacing 50 RALPH R. STEVENS. between the opposed surfaces which varies con~ tinuously thereover in any phase of vibration of REFERENCES CITED the one electrode. The following references are of record in the 2. A telephone transmitter comprising a ?xed ?le of this patent? electrode having a plurality of surfaces of which 55 UNITED STATES PATENTS one is a concave surface, a vibratile electrode having a convex surface of continously. changing Number Name Date curvature in juxtaposition to said concave sur face, means including said concave and convex surfaces bounding a chamber, and comminuted resistance varying material in said chamber. 3. A telephone transmitter comprising a pair of electrodes having each a surface including a dished portion the dished portions being juxta 2,014,427 2,042,822 2,191,992 2,225,488 2,302,278 Eaton ___________ __ Sept. 17, Bennett __________ __ June 2, McLarn __________ __ Feb. 27, Stevens __________ __ Dec. 17, Voorhoeve _______ __ Nov. 17, 1935 1936 1940 1940 1942 2,320,433. Herckmans _______ __ June 1, 1943 2,429,988 Bryant ___________ __ Nov. 4, 1947 .