US1550381A - Electrostatic telephone - Google Patents

Electrostatic telephone Download PDF

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Publication number
US1550381A
US1550381A US518425A US51842521A US1550381A US 1550381 A US1550381 A US 1550381A US 518425 A US518425 A US 518425A US 51842521 A US51842521 A US 51842521A US 1550381 A US1550381 A US 1550381A
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United States
Prior art keywords
diaphragm
plate
ring
diaphragms
metal
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US518425A
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English (en)
Inventor
Massolle Joseph
Vogt Hans
Engl Josef
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TRI ERGON Ltd
TRI-ERGON Ltd
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TRI ERGON Ltd
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Filing date
Publication date
Priority to DENDAT368900D priority Critical patent/DE368900C/de
Application filed by TRI ERGON Ltd filed Critical TRI ERGON Ltd
Priority to US518425A priority patent/US1550381A/en
Application granted granted Critical
Publication of US1550381A publication Critical patent/US1550381A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/02—Loudspeakers

Definitions

  • JOSEPH MASSOLLE OF BERLIN-GRUNEWALD, HANS VOGT, OF BERLIN-SCHONEBERG, AND JOSEF ENGL, 0F BEBLIN-GRUNEWALD, GERMANY, ASSIGNORS '10 TRI-ERGON LIMITED, OF ZURICH, SWITZERLAND.
  • the invention relates to electrostatic telephones, with especial reference to the use of the same for reproducing music and speech.
  • Objects of the 'imzrmtion comprise the provision of means whereby the acousticallymodulated currents, or sounds, operating the same, will cause such operation in a particularly faithful, reliable and efficient manner, and with a minimum of distortion.
  • Other objects comprise the provision of improved combinations of parts and details of construction, all as will be more fully set forth in the following specification, and be particularly set forth in the appended claims.
  • the distance between the'diaphragm and its counter plate is of great importance in electro-static telephones. As both parts must be mutually well insulated the production of a spacing of for instance some hundredths of a -millimeter is rather difficult.
  • the well known insulation by plates of ebonite or similar material which is submitted to the effects of heat, moisture and the like is quite insufficient as these substances are submitted to continuous variations of shape.
  • This invention avoids these inconveniences by making from metal all the parts which are essential for the production of the gap between the fixed condenser plate and the diaphragm, said parts being insulated at the critical spacing parts by thin disks, for instance of mica, which are clamped in between the metal parts.
  • Fig. 1 shows a vertical section through one form of construction.
  • Figs. 2 to 11 are similar sections of modified forms of construction.
  • Fig. 10 is a partial edge section-through one form of construction, which may be considered as a continuation of Fig. 10 to complete the same.
  • a supporting plate preferably of metal into whic the unitary condenser plate 79 which'is made also of metal, is screwed in order to make the distance, between the same and the diaphragm, adjustable;
  • the clamping ring In, Figs. 1 to 4, serves to clamp the edge of the diaphragm upon the supporting plate, screws sch being extended through ring 70 and the diaphragm and into plate g.
  • the diaphragm m consists according to Fig. 1 of a foil of metal orof a non-conducting material which is coated with electrically conducting material either upon one side or upon both sides.
  • the insulation between plate 9 and ring In is effected in the form of construction shown in Fig. 1, by interposed rings 21 and 71 for instance of thin mica, or impregnated paper or the like. These insulating rings can extend beyond the edges of plate 9 in order to lengthen the creeping paths.
  • the holes for the screws in the diaphragm are sufiiciently wide to allow for creeplng.
  • thin metal foils can be inserted between i' and m and i and g. Y
  • the electrical connections can be effected in the case of metal diaphragms or with diaphragms 'which are coated upon one side only, by
  • clamping ring sp is screwed into the metal clamping ring k.
  • the tension of the diaphragm is regulated by the screwing in of the clamping ring sp.
  • An abutment w is preferably arrangedupon the sup orting plate 9 for ensuring maintenance parallelism between p and m, the diaphragm being firmly pressed against this abutment with interposition of the insulating ring 2'.
  • ring is also from insulating material, this being possible as the accuracy of distance between plate p and m is ensured by the abutment w.
  • IVith metallic diaphragms or with such diaphragms which are coated with conducting material upon both sides 11 is quite sufficient for insulating.
  • ⁇ Vith diaphragms of insulating material which are coated upon one side only no insulating ring is required if the conducting coating is situated at the same side as is.
  • Fig. 2 shows an even simpler form of construction as in this case the single conductin coatin 2 u on the side of dia avoira m b b 2 b m towards ring 7; is of the same diameter as the conducting connection ring a. Consequently as the diaphragm itself consists of an insulator, a non-conducting circular ring is situated between 9 and in. As ring a is insulated from k by 8;) the diaphragm m can be clamped in between 9 and 70 without additional insulation.
  • the point on the oscillating coating having the least distance from the fixed coat or plate determines the distance between the coatings. This point oscillates with maximum amplitude and all other points on the diaphragm or movable coat oscillate with a less amplitude. If the point of greatest amplitude is situated outside the center of the diaphragm, the diaphragm will oscillate unsymmetrically. Since the strength of the sound reproduced varies as the square of the distance between the coating of the diaphragm and the plate and as the distance rerequired for the greatest efiiciency amounts to only several hundredths of a. millimeter, the slightest irregularities have a very important effect upon the result.
  • the present invention permits the obtaining and maintenance of accurate distances of the diaphragm, or movable condenser coating, from the plate, down to a few hundredths of a millimeter.
  • the solid condenser plate made from metal is provided with one or several rings whose end surface is parallel with the surface of the plate, and the diaphragm is securely fixed upon the said ring or upon the rings.
  • the distance between the fixed and movable condenser elements is either produced by these rings or by the intermediate In Fig. 3 b and k are rin s between which layers of metal foil, mica, paper or the like which can serve at the same time for insulating metallic diaphragms.
  • Figs. 3 to 10 show forms of construction.
  • Ring 6 is preferably made from insulating material and k can be made of metal.
  • the diaphragm is also an insulator consisting for instance of mica and having a conducting coating 6 upon one side only.
  • the solid condenser plate 9 of metal with the coated surface Z) of an electric conductive material isscrewed by means of threads g into 6. and it is provided according to the invention with a ring 1' whose front surface is parallel with b and projects forwardly beyond surface I) for an amount which is equal to the distance to be produced between I) and m.
  • the diaphragm is in close contact with ring 7", being for instance pressed upon the same by ring a which, if k is an insulator, is made of metal in order to establish the electric connection of the coating of the diaphragm.
  • a tension is given to the diaphragm which can be regulated by means of the screw threads 9' and 9 Fig. at differs from Fig. 3 by 5., and p being united to form a body which is entirely made of metal so that the tension of the diaphragm is no longer adjustable but 1 determined by the difference of height between f and 7.
  • the insulation between F) and b is produced by the ring 2' and the diaphragm m, the latter being coated with conducting material only up to the outer diameter of a.
  • the diaphragm is not tensioned when the ring a is being screwed home as 7 and f are of .equal height.
  • the diaphragm must 0 therefore be inserted, if it is not sufficiently rigid, in tensioned state, for instance with the aid of a separate tensioning device.
  • This form of construction is otherwise the same as that shown on Fig. 4.
  • r, f, and b are of the same height.
  • the distance of the diaphragm from the surface 6 of the plate is in this case determined by the intermediate rings .2 which can be made of metal.
  • the conducting ring a and insulator 2' are modified in so far as a is not screwable but clamped in by '5 when the screws 8 are being screwed home.
  • the member 71 is preferably made from elastic material for instance soft rubber, where- 1 by the intimate contact of m and 2 upon 1' is ensured. 2 determines the distance between the diaphragm and the solid plate.
  • the intermediate rings 2i and 22' are consequently made of insulating material for instance of mica or paper, the latter. being preferably impregnated with insulating material.
  • Fig. 8 shows the form of construction of Fig. 7 for a telephone of the bilateral action type.
  • b and b are the outer coatings, and b (m) is the diaphragm between said coatings.
  • N 0 separate rings r are provided and the surface f is parallel to b and replaces r.
  • Fig. 10 shows the use of the ring r in connection with sub-divided diaphragms or with such diaphragms which are fixed at the center.
  • r is the central support
  • 1" and r are subdividing rings Wlth telephones acting at one side only the diaphragm is deflected always towards one side. If the plate surface 6' is straight the distance between this surface and the diaphragm will therefore get narrower towards the center.
  • Thisdefiection can be compensated by making 6' or b concave as shown on Figs. 9 and 10. It is not necessary that b and 1' be made of one metal piece, they could be composed also of two metallic parts.-
  • the diaphragm can be tensioned radially so that thin and light diaphragms can be used.
  • the net weight. and the pitch of the tone at a given diameter are critical, specially if such telephones are to be. utilized for reproducing musical or talking currents. Owing to the high pitched frequencies which are to be reproduced the diaphragm itself must possess a comparatively high natural rate of vibration as otherwise the high pitched frequencies would be reproduced at unduly low sound intensity in comparison to the deep pitched frequencies.
  • thin mica is used as material for diaphragms and the diaphragms made from this material have a sufficiently low weight and sufiicient capability of tension.
  • Diaphragms of this type, utilized in this invention having a thickness of some hundredths of a millimeter and having a diameter up to one half meter, and can be put under sufliciently strong tension.
  • the tensioning of the diaphragm is preferably efiected'in such a manner that the diaphragm is radually tensioned. more and'more and t lat after each tensioning the natural itch of tone is ascertained.
  • mica diaphragins presents the further advantage that the elastic limit is quite-close to the limit of the tensile strength, as can be proved by controlling the pitch of tone while the tensioning is proceeding, whereas the hitherto used materials for diaphragms begin to deform before the rupture if the elastic limit is exceeded. Therefore, subjected to high tensions.
  • the diaphragm described possesses as another advantage a large time constancy, owing to the low elasticity of the mica so that its tension will be preserved for a long time.
  • the mica is further, owing to the hardness of its surface, a material which is specially adapted for the production of sound and which is much superior to, for instance paper or thin skins, being besides not hygroscopic.
  • the dielectric required in the condenser telephone is, further, in the preferred form of the invention, rigidly connected with the diaphragm or movable condenser plate, the mica diaphragm itself constituting the dielectric which carries the metallic or conducting coating, which constitutes the movable plate of the condenser, said dielectric being already known for electro-statio telephones as insulation between the diaphragm and its counter plate.
  • Fig. 11 shows a form of construction of mica diaphragms can be this arrangement
  • 9 is the supporting plate made for instance from insulating material upon which the condenser plate pg is fiXed.
  • the edge portion of the diaphragm is clamped upon the annular projection of the plate 9 by the clamping ring 1' and the screw 8.
  • the diaphragm is preferably made from mica, glass, paper, gold-beaters skin or similar substances.
  • the diaphragm has upon one side a coating p m of conducting material which may be produced in various ways, as by a galvanizing process (for instance by silver-plating). In this method the silver coating is preferably deposited on the diaphragm from a solution comprising silver nitrate and other substances.
  • the diaphragm is mounted in such a manner that it is situated as dielectric between p m and p g.
  • p 9 can have a number of perforations Z for reducing the damping of the air gap d.
  • the clamping ring r can for instance be made of metal and it can have a connecting screw.
  • a. fixed condenser plate a diaphragm closely adjacent thereto, and means for clamping said diaphragm in position under tension, comprising a member (opposite the center of the diaphragm and ringmembers concentric therewith, to provide annular separately-vibratory diaphragm portions of difi'ere'ntwidths one from the other, said plate having seating portions between which and said members the diaphragm will be clamped.
  • a fixed condenser plate a diaphragm closely adjacent thereto, and means for clamping said diaphragm in position, comprising a plurality of members engaging the diaphragm to divide the latter intoa plurality of separately-vibratory portions, said plate having correspondingl shaped seating portions between which and said members the diaphragm is clamped, said plate having slightly concaved faces opposite the said separately-vibratory portions of said diaphragm.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Vibration Prevention Devices (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
US518425A 1921-11-28 1921-11-28 Electrostatic telephone Expired - Lifetime US1550381A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DENDAT368900D DE368900C (de) 1921-11-28
US518425A US1550381A (en) 1921-11-28 1921-11-28 Electrostatic telephone

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US518425A US1550381A (en) 1921-11-28 1921-11-28 Electrostatic telephone

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US1550381A true US1550381A (en) 1925-08-18

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2435519A (en) * 1944-02-14 1948-02-03 Rca Corp Image-forming heat detector
US2445821A (en) * 1944-03-29 1948-07-27 Noble E Brewer Condenser microphone
US2509310A (en) * 1948-02-03 1950-05-30 George L Carrington Microphone or receiver of the condenser type
US2631196A (en) * 1949-10-05 1953-03-10 Arthur A Janszen Electrostatic loud-speaker
US3008014A (en) * 1954-07-20 1961-11-07 Ferranti Ltd Electrostatic loudspeakers
FR2424683A1 (fr) * 1978-04-25 1979-11-23 Polaroid Corp Procede pour monter une membrane dans un transducteur electroacoustique, et transducteur ainsi obtenu
US8973924B2 (en) 2013-04-03 2015-03-10 Skis Rossignol Device for adjusting the position of the boot support holder in a ski fastening system
US20160014521A1 (en) * 2014-07-08 2016-01-14 Samsung Display Co., Ltd. Transducer and electronic device including the same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4321432A (en) * 1978-12-23 1982-03-23 Tokyo Shibaura Denki Kabushiki Kaisha Electrostatic microphone

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2435519A (en) * 1944-02-14 1948-02-03 Rca Corp Image-forming heat detector
US2445821A (en) * 1944-03-29 1948-07-27 Noble E Brewer Condenser microphone
US2509310A (en) * 1948-02-03 1950-05-30 George L Carrington Microphone or receiver of the condenser type
US2631196A (en) * 1949-10-05 1953-03-10 Arthur A Janszen Electrostatic loud-speaker
US3008014A (en) * 1954-07-20 1961-11-07 Ferranti Ltd Electrostatic loudspeakers
FR2424683A1 (fr) * 1978-04-25 1979-11-23 Polaroid Corp Procede pour monter une membrane dans un transducteur electroacoustique, et transducteur ainsi obtenu
US4215249A (en) * 1978-04-25 1980-07-29 Polaroid Corporation Method and device for controlling wrinkles in a vibratile diaphragm
US8973924B2 (en) 2013-04-03 2015-03-10 Skis Rossignol Device for adjusting the position of the boot support holder in a ski fastening system
US20160014521A1 (en) * 2014-07-08 2016-01-14 Samsung Display Co., Ltd. Transducer and electronic device including the same
US9516420B2 (en) * 2014-07-08 2016-12-06 Samsung Display Co., Ltd. Transducer and electronic device including the same

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Publication number Publication date
DE368900C (de)

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