WO1981002072A1 - Diaphragme acoustique a epaisseur variable, dipositifs a bobine vocale pour transducteurs electro-acoustiques - Google Patents

Diaphragme acoustique a epaisseur variable, dipositifs a bobine vocale pour transducteurs electro-acoustiques Download PDF

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Publication number
WO1981002072A1
WO1981002072A1 PCT/US1981/000007 US8100007W WO8102072A1 WO 1981002072 A1 WO1981002072 A1 WO 1981002072A1 US 8100007 W US8100007 W US 8100007W WO 8102072 A1 WO8102072 A1 WO 8102072A1
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WO
WIPO (PCT)
Prior art keywords
diaphragm
thickness
peripheral edge
windings
current conduction
Prior art date
Application number
PCT/US1981/000007
Other languages
English (en)
Inventor
E Willy
Original Assignee
E Willy
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by E Willy filed Critical E Willy
Priority to DE19813129770 priority Critical patent/DE3129770A1/de
Publication of WO1981002072A1 publication Critical patent/WO1981002072A1/fr

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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K13/00—Cones, diaphragms, or the like, for emitting or receiving sound in general
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H04R7/127—Non-planar diaphragms or cones dome-shaped
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/04—Construction, mounting, or centering of coil
    • H04R9/046—Construction

Definitions

  • This invention relates generally to electroacoustic transducers, and more particularly, to a peripherally-driven electroacoustic transducer hav ⁇ ing a variable thickness diaphragm.
  • a peripheral drive electromagnetic trans ⁇ ducer was developed by the inventor of the present application and is dis ⁇ closed in U. S . Patent No. 3, 979, 566 which issued on September 7, 1976 and which is incorporated herein by reference. Specifically, as shown in that patent, a peripheral lip of a diaphragm is wound with a coil. This lip with the coil on it is inserted between a pair of pole pieces. With this arrange ⁇ ment, the driving force is applied to the peripheral edges of the diaphragm rather than to the center thereof. As a result, significant improvements in overall efficiency have been attained. Further, when used as a speaker, a wide dispersion is achieved for the propagation of the sound throughout a wide frequency range including high frequencies . The present invention relates to further improvements in these characteristics in the use of a new diaphragm for peripherally-driven electroacoustic transducers.
  • Another object of the present invention is to improve the efficiency of a peripherally-driven electroacoustic transducer.
  • a further object of the present invention is to reduce skin effects and the capacitance between windings in periphrally-driven electroacoustic transducers.
  • Yet another object of the present invention is to reduce the impedance at high frequencies to keep the impedance relatively constant at audio fre ⁇ quencies.
  • Still another object of the present invention is to provide a self -inflat ⁇ ing feature for a variable thickness diaphragm to allow for exceptionally lightweight diaphragms.
  • the present invention contem ⁇ plates a diaphragm for use with peripheral-driven electroacoustic transduc ⁇ ers wherein the diaphragm is of variable thickness with its thinnest portion along the peripheral edge thereof. This diaphragm thickness gradually in ⁇ creases to a point of maximum thickness located in a portion of the diaphragm other than at the peripheral edge.
  • the diaphragm can be solid or hollow. Further, the diaphragm can be provided with a self-inflating arrangement.
  • Fig. 1 is a perspective view of the diaphragm and coil windings in an electroacoustic transducer according to the present invention
  • Fig. 2 is a cross-sectional view of Fig. 1 taken along section lines 2-2 of Fig. 1;
  • Fig. 3 is a cross-sectional view of an alternative embodiment of the pres ⁇ ent invention.
  • Fig. 4 is a cross-sectional view of another embodiment of the present invention .
  • Fig. 5 is a front view of an embodiment of the present invention utiliz ⁇ ing a wooden diaphragm
  • Fig. 6 is a cross-sectional view of another embodiment of the present invention including a self -inflating feature
  • Fig. 7 shows alternative wiring arrangements which can be utilized in the present invention.
  • a diaphragm 12 is shown for use in an electroacoustic transducer such as a speaker or a microphone.
  • This diaphragm 12 is shown having a variable thickness in Fig. 2 with a thick portion approximately in the center and the thickness gradually tapering off to the thinnest portion at the peripheral edges 14.
  • a lip 16 is provided around the periphery of the diaphragm 12, and an electrical coil 18 is wound around this lip 16.
  • the outer surface 20 is convex while the inner surface 22 is concave .
  • variable thickness of the diaphragm 12 allows the estab ⁇ lishment of zones for a tweeter A, an intermediate range B and a woofer C .
  • the tweeter is effectively a ring running along the peripheral portion of the diaphragm, while the woofer covers the entire diaphragm area. This allows for one of the significant advantages of the present invention in that the highest frequency signals have the least mass since they are spaced furthest from the thickened center of the diaphragm 12.
  • another aspect of the present invention involves spacing wires apart by a distance D approximately equal to the diameter of the windings, as shown in Figs. 1 and 2.
  • the present invention contemplates the use of Litz wires for such windings.
  • Litz wire reduces the skin effect and also significantly improves the high frequency response of the system.
  • it also helps to reduce the impedance at high frequencies which maintains a constant Z at audio frequencies .
  • Fig. 2 illustrates one particular method of proportioning the surface for a convex-concave arrangement.
  • the convex outer surface of the diaphragm is formed in accordance with a first radius R, while the inner surface of the diaphragm is formed by a second radius R ? which is longer than R , .
  • the origin points for the radii R , and R ? lie along a common axis extending through these origins and the center of the diaphragm .
  • a dis ⁇ tance D between these origin points equals Renfin - R , + t where t is the desired thickness at the center of the diaphragm.
  • the actual particular dimensions of thickness chosen for the diaphragm 12 for use in an electroacoustic transducer such as a speaker or a micro ⁇ phone vary depending on the diameter of the diaphragm and the frequency response desired. For example, if one were to use a speaker with a dia ⁇ phragm diameter of approximately 10 inches, and desired a frequency range approximately between 30 Hz to 30 kHz, the thickness can be set at the center between an 1/8 and 3/16 inch., tapering out " to between 0.003 and 0.005 inch at the edge. Of course, the particular dimensions also depend on the particular characteristics of the material being used.
  • spaced Litz wire as discussed above, having a wire thickness of approximately 0.015 inch and a gap width of between 0.030 and 0.040 for the air gap between the pole pieces into which the diameter lip is inserted, as shown in U. S. Patent No. 3, 979, 566, a maximum flux density in the vicinity of 12000 gauss is pro ⁇ quizd. This will produce a speaker diaphragm approximately within the range of 30 Hz to 30 kHz. It is to be noted that the number of turns for the coil winding will depend upon the desired impedance, typically 4 or 8 ohms, and can be determined in a manner well known in the art.
  • the particular shape of the surfaces of the diaphragm is not limited to the convex-concave arrangement shown in Fig. 2.
  • Fig. 3 shows an arrangement with both the outer surface 24 and the inner surface 26 being convex.
  • the outer surface 24 can be formed with a constant radius in the * same manner as the outer surface 20 of Fig. 2.
  • the inner surface 26, on the other hand, is made with a constant radius from a point also on the center line of the diaphragm but with the origin point on the other side of the dia ⁇ phragm.
  • FIG. 4 Another example of a possible variable thickness diaphragm is shown for the invention in Fig. 4.
  • a linear taper is provided from the center of the diaphragm to the peripheral edges.
  • the material chosen for the variable thickness should be one capable of good frequency response while being lightweight, durable, and capable of good reproducibility of diaphragm construction (i.e. with the same basic sound characteristics) .
  • Certain plastics have been found to possess these qualities.
  • the polycarbonate plastic manufactured under the trademark Lexan by the General Electric Company is suitable for use invention due to its strength and easy workability.
  • other plastics with the above characteristics should also be suitable.
  • certain types of flexible, and preferably unbreakable, glass which are commercially avail ⁇ able could be used.
  • a diaphragm 12 is formed with a thin wooden sheet 32.
  • fre ⁇ quency response with such wood, it has been found best to cut across the grain so that the rings of the wood will form approximately concentric circles around the center thereof .
  • the wood is first boiled to remove the sap in a manner which is well . known. Subsequently, fillers such as that sold under the commercial trade ⁇ mark "Plastic Wood" can be added .
  • FIG. 6 Another embodiment of the present invention is shown in Fig . 6. Specifically, in Fig. 6, rather than forming the diaphragm as a solid piece such as shown in Figs. 1 through 5, an outer sheet 34 and an inner sheet 36 are provided with an air space 37 therebetween. Each of these sheets 34 and 36 includes an opening 38 and 40, respectively, with valve covers 42 and 44 covering these openings respectively. . As shown in Fig . 6, the valve covers 42 and 44 are arranged to open based on the direction of movement of the respective sheets 34 and 36 to which they are attached. Specifically, valve cover 42 opens when the outer sheet 34 moves io a forward direction . This valve 42 will open as long as the air pressure inside the air space 37 is less than the pressure exerted by the forward movement of the sheet 34. On the other hand, the valve cover 44 opens whenever the sheet 36 moves in a back ⁇ ward direction. Of course, this valve 44 will also open only as long as the air pressure inside the air space 37 is less than the pressure exerted by the backward movement of the
  • valve cover 42 Based on the operation of the valve covers 42 and 44, a self -inflating action takes place during vibration of the diaphragm.
  • the air rushing into the air space 37 helps ensure closure of the valve cover 44.
  • the valve cover 44 opens, the air rushing in there helps to close the valve cover 42.
  • air only enters during movement in either direction once the air pressure inside the space 37 is sufficient to hold the valve covers closed while the diaphragm is inactive. As more air is admitted, the diaphragm will rapidly inflate to a point where the air pressure inside is sufficiently greater than the outside air pressure to hold the valve covers closed even during movement of the diaphragm.
  • the diaphragm would rapidly fill up to this point in less than a second. And, any subse ⁇ quent loss of air due to leakage will rapidly be compensated for upon move ⁇ ment of the diaphragm.
  • valve covers 42 and 44 are made as light and small as possible to avoid any undesirable fluttering thereof. And, of course, they must provide a good seal for the opening to prevent any leakage of air dur ⁇ ing and upon reaching the desired inflation level . It is noted that the use of cellophane valve covers with a thickness of O.D01 inch and a rather small opening of 0.03 inch is one example of a suitable material and appropriate opening sizes for the valve covers.
  • a good material for use in the self -inflating diaphragm for the sheets 34 and 36 is the poly ⁇ carbonate manufactured as Lexan. These sheets can be provided with a thickness, for example, of approximately 0.005 inch . Such sheets can be rapidly formed by vacuum forming to be assembled with one another. These sheets have sufficient stiffness to remain in a concave-convex arrangement as shown in Fig . 6, if desired. However, one could, of course, also form these into a con ve -convex arrangement if desired.
  • FIG. 3 An alternative wiring arrangement which can be used in any of the above eirbodiments, or, for that matter, with a conventional center-driven diaphragm, is shown in Fig. 3.
  • the outer windings 46 and 48 of the coil winding 18 are in the opposite direction relative to the direction of the center windings 50. This is also shown, for the coil alone, in Fig. 7.
  • Figs. 1, 3 and 4 are shown as being solid diaphragms, they could have an internal . opening if desired, especially in a situation where extreme lightweight is desired.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)

Abstract

Le domaine technique est l'acoustique, essentiellement, l'electro-acoustique, en particulier les transducteurs acoustiques (haut-parleurs et microphones). Pour ameliorer la plage de reponse de rendement, de dispersion et de frequence, des diaphragmes actionnes sur la peripherie ont ete proposes anterieurement. Essentiellement, ces objectifs et solutions sont pousses plus loin par une construction particuliere d'un diaphragme et/ou un dispositif particulier de commande de bobine vocale mobile. Le diaphragme (12) possede une epaisseur variable (figures 2, 3, 4 et 6). Son epaisseur la plus fine est a sa peripherie (14) et la plus grosse a proximite de son centre. La surface vers l'avant est convexe (20, 24, 28 et 34). La surface arriere peut etre convexe (26 et 30) ou concave (22 et 36). La section peut etre lineaire (figure 4) ou courbe (figures 2, 3 et 6). Le diaphragme peut etre rempli d'air, construit avec deux films et un dispositif a valve pour assurer un auto-gonflage rapide (figure 6). Les spires de la bobine vocale (18) sont espacees entre elles (d). On utilise du fil de Litz. L'enroulement de la bobine vocale mobile est enroule en trois sections (figures 3 et 7), a savoir une section centrale (50) et des sections exterieures opposees (46 et 48). Le sens d'enroulement de la section centrale est oppose a celui des sections externes. Une reaction negative est ainsi produite pour reduire au minimum la tendance de mouvement de la bobine le long de son support et par consequent reduire au minimum la distorsion des basses. Cet enroulement a multi-sections est utile avec d'autres dispositifs conventionnels.
PCT/US1981/000007 1980-01-04 1981-01-05 Diaphragme acoustique a epaisseur variable, dipositifs a bobine vocale pour transducteurs electro-acoustiques WO1981002072A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19813129770 DE3129770A1 (de) 1980-01-04 1981-01-05 Variable thickness a acoustic diaphragm,voice coil arrangements for electroacoustic transducers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US109500 1980-01-04
US06/109,500 US4532383A (en) 1980-01-04 1980-01-04 Electroacoustic transducer having a variable thickness diaphragm

Publications (1)

Publication Number Publication Date
WO1981002072A1 true WO1981002072A1 (fr) 1981-07-23

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PCT/US1981/000007 WO1981002072A1 (fr) 1980-01-04 1981-01-05 Diaphragme acoustique a epaisseur variable, dipositifs a bobine vocale pour transducteurs electro-acoustiques

Country Status (4)

Country Link
US (1) US4532383A (fr)
JP (1) JPS56501862A (fr)
GB (1) GB2078464A (fr)
WO (1) WO1981002072A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3831376A1 (de) * 1988-09-15 1990-03-22 Filip Keller Lautsprecher oder mikrofon
RU2523094C2 (ru) * 2008-10-21 2014-07-20 Лаутшпрехер Тойфель Гмбх Низкочастотный громкоговоритель с плоским диффузором и его применение
KR101791610B1 (ko) 2014-01-26 2017-10-30 고어텍 인크 다중 진동막 스피커 시스템

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Publication number Priority date Publication date Assignee Title
US5033093A (en) * 1990-01-17 1991-07-16 Peavey Electronics Corporation Compact microphone and method of manufacture
DE3838853C1 (fr) * 1988-09-30 1989-11-30 Ant Nachrichtentechnik Gmbh, 7150 Backnang, De
DE4329982C2 (de) * 1993-09-04 2003-05-28 Sennheiser Electronic Elektrodynamischer Schallwandler
US6282298B1 (en) * 1996-09-03 2001-08-28 New Transducers Limited Acoustic device
AT405997B (de) * 1997-04-30 2000-01-25 Akg Acoustics Gmbh Elektroakustischer wandler
WO2002011495A2 (fr) * 2000-07-31 2002-02-07 Harman International Industries, Inc. Systeme de suspension de bobine de haut-parleur
JP4557412B2 (ja) 2000-11-20 2010-10-06 パナソニック株式会社 スピーカ
US6839444B2 (en) 2000-11-30 2005-01-04 New Transducers Limited Loudspeakers
CN1905756A (zh) * 2005-07-29 2007-01-31 富准精密工业(深圳)有限公司 微型电声装置的音膜
CN101304622A (zh) * 2007-05-09 2008-11-12 富准精密工业(深圳)有限公司 电声装置的音膜结构及其制备方法
FR2955446B1 (fr) 2010-01-15 2015-06-05 Phl Audio Transducteur electrodynamique a dome et suspension flottante
FR2955445B1 (fr) 2010-01-15 2013-06-07 Phl Audio Transducteur electrodynamique a dome et suspension interne
FR2955444B1 (fr) 2010-01-15 2012-08-03 Phl Audio Systeme de haut-parleur coaxial a chambre de compression
DE102010027780A1 (de) * 2010-04-15 2011-10-20 Robert Bosch Gmbh Verfahren zum Ansteuern eines Ultraschallsensors und Ultraschallsensor
GB2505953B (en) 2012-09-18 2019-05-08 B & W Group Ltd Stepped thickness change in dome-shaped diaphragms for loudspeaker drive units or microphones
US9332352B2 (en) * 2013-02-25 2016-05-03 Apple Inc. Audio speaker with sandwich-structured composite diaphragm
CH708956B1 (fr) * 2013-12-09 2021-08-31 Montres Breguet Sa Membrane de rayonnement acoustique pour une montre musicale.
US9584886B2 (en) * 2014-07-16 2017-02-28 Htc Corporation Micro-speaker
US9900698B2 (en) * 2015-06-30 2018-02-20 Apple Inc. Graphene composite acoustic diaphragm
US10433070B2 (en) * 2018-03-02 2019-10-01 Infineon Technologies Ag Sensitivity compensation for capacitive MEMS device
CN208386924U (zh) * 2018-05-07 2019-01-15 惠州超声音响有限公司 一种具有隐藏式折环的扬声器
WO2020084395A1 (fr) * 2018-10-24 2020-04-30 Cochlear Limited Capteurs acoustiques implantables à diaphragmes non uniformes

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US1713006A (en) * 1923-11-29 1929-05-14 Rca Corp Telephone and the like
GB348425A (en) * 1929-07-01 1931-05-14 Eric Morton Matthew Improvements in or relating to sound reproducers or transmitters
US1999862A (en) * 1930-11-21 1935-04-30 Bowles Edward Lindley Acoustic-electric-energy converter
US2034882A (en) * 1933-05-24 1936-03-24 Thomaston Lab Inc Loudspeaker
US2205365A (en) * 1938-07-18 1940-06-18 Marguerite Schwaen Radio receiver
FR864516A (fr) * 1939-03-28 1941-04-29 Loewe Opta Gmbh Perfectionnements aux systèmes de haut-parleurs
US2926741A (en) * 1958-04-28 1960-03-01 Lab Equipment Corp Speaker
DE2241445A1 (de) * 1972-08-23 1974-03-21 Gottlob Widmann & Soehne Gmbh Kalottenmembran fuer lautsprecher
US3979566A (en) * 1973-12-12 1976-09-07 Erazm Alfred Willy Electromagnetic transducer
US4088847A (en) * 1975-12-11 1978-05-09 Matsushita Electric Industrial Co., Ltd. Speaker voice coil construction
US4140203A (en) * 1976-05-17 1979-02-20 Matsushita Electric Industrial Co., Ltd. Acoustic diaphragm with polyurethane elastomer coating

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1713006A (en) * 1923-11-29 1929-05-14 Rca Corp Telephone and the like
GB348425A (en) * 1929-07-01 1931-05-14 Eric Morton Matthew Improvements in or relating to sound reproducers or transmitters
US1999862A (en) * 1930-11-21 1935-04-30 Bowles Edward Lindley Acoustic-electric-energy converter
US2034882A (en) * 1933-05-24 1936-03-24 Thomaston Lab Inc Loudspeaker
US2205365A (en) * 1938-07-18 1940-06-18 Marguerite Schwaen Radio receiver
FR864516A (fr) * 1939-03-28 1941-04-29 Loewe Opta Gmbh Perfectionnements aux systèmes de haut-parleurs
US2926741A (en) * 1958-04-28 1960-03-01 Lab Equipment Corp Speaker
DE2241445A1 (de) * 1972-08-23 1974-03-21 Gottlob Widmann & Soehne Gmbh Kalottenmembran fuer lautsprecher
US3979566A (en) * 1973-12-12 1976-09-07 Erazm Alfred Willy Electromagnetic transducer
US4088847A (en) * 1975-12-11 1978-05-09 Matsushita Electric Industrial Co., Ltd. Speaker voice coil construction
US4140203A (en) * 1976-05-17 1979-02-20 Matsushita Electric Industrial Co., Ltd. Acoustic diaphragm with polyurethane elastomer coating

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3831376A1 (de) * 1988-09-15 1990-03-22 Filip Keller Lautsprecher oder mikrofon
RU2523094C2 (ru) * 2008-10-21 2014-07-20 Лаутшпрехер Тойфель Гмбх Низкочастотный громкоговоритель с плоским диффузором и его применение
KR101791610B1 (ko) 2014-01-26 2017-10-30 고어텍 인크 다중 진동막 스피커 시스템

Also Published As

Publication number Publication date
JPS56501862A (fr) 1981-12-17
US4532383A (en) 1985-07-30
GB2078464A (en) 1982-01-06

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