DE1462174A1 - Electroacoustic converter - Google Patents

Description

PATENT ADVOCATE
DUPLICATION.

HELMUT GORTZ

Froo ^? .iy; f a. Morn

December 10, 1965 PA Schw / Schr

fflOTOROLA, INCORPORATED 9401 West Grand Avenue »Franklin Park, Illinois, U.S.A.

Electroacoustic converter

The 'invention relates to electroacoustic transducers and, in particular, to a loudspeaker, bai the as a drive aamant an organ is used, the dimensions of which can be changed depending on ainam signal »

Saint operation of dynamic speakers »which are used to create * If high-frequency sound signals are used from applied electrical signals, there are numerous problems. The dynamic loudspeaker normally operates above its resonant frequency and requires therefore a considerable amount of power for the drive of the loudspeaker membrane “when is the frequency characteristic of a dynamic loudspeaker” in connection with another Loudspeakers as soon as they should be influenced are electrical coupling networks or switches required, which the public address system in addition Complicate * Will be at one above the resonance frequency transients can become a problem, especially when compared to operating the loudspeaker below the frequency Resonance bullet. When signals above and below the If the resonance frequency of the loudspeaker system is given, no smooth transition occurs when the given signals pass through the resonance frequency and come

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ea on phase errors «Different known speakers with masaivan Drive Alams revealed that Kainan was fully satisfied Efficiency, among other things to a considerable extent on aina butcher coupling or adaptation of the Ufandlars to dia air attributed to eats. Known dynamic speakers or other speakers were fraught with these difficulties, and the Manufacturing costs of such loudspeakers or associated circuits increased when an attempt was made to rectify the defect remove.

One aim of the present invention is therefore one or to eliminate several of the problems outlined above and to create an improved and simplified loudspeaker »represents can be manufactured with a reduced diet.

Another goal is to increase efficiency a high frequency speaker or horn.

The invention of bazmack; further the creation of a loudspeaker, operated by inr) 3rh; jlb of a frequency band and can be used together with another loudspeaker without electrical coupling networks required are.

A feature of the invention is the creation of a loudspeaker with a drive element that can be changed in sa.Lnar dimension, which works as a length expander and is unnit: albar coupled to the loudspeaker membrane

Another feature of the invention is the provision of one Loudspeaker, which has an elongated, in its dimensions, changeable drive element, signals below represents the longitudinal reionant frequency of the drive element and at dam the Uuerechnittsflache the drive element is selected so that) a better coupling of the loudspeaker received on dia Ljft.

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A further feature of the invention is the creation of a loudspeaker with a tapered ceramic support element to increase the limit frequency of the loudspeaker when using a keraniachan element of a maximum length. ■ · ■ ". ' ^: ':. '. ■;';;' . · '■■

A waiting feature of the invention is the creation of a Loudspeaker with a sine drive element from diner Ehrzehl ceramic elements, dia together ainan bimorphan lengths » form expander *,:

Further features, advantages and benefits of the The invention can be found in the following description of embodiments in conjunction with the enclosed Drawings. ^ '

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Figure 1

a ι cross section of a loudspeaker "it a" ceramic! * drive element »

Figure 2 shows a cross section of the karamiechan drive elements according to Fig. 1,

Figure 3 shows a ceramic drive element in the form of a fishing plate /

Figure 4 shows a karanlschaa drive area in the form of a self linear tapered fishing plate,

Figure 5 is a Keramiachsa drive element in the form of a exponentially tapering fish tcsrsmischan plate, and

FIG. 6 a bimorphic ceramic propulsion oilant working as a length expander.

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U62174

With the invention, a funnel loudspeaker was created » the high-frequency sound signals applied to him accordingly electrical signals generated. The loudspeaker basks a frame and one mechanically supported by the Rahman Membrane on. An elongated drive element, for example a ceramic part | is with the frame and as a KoI-ban working war, braη connected «are on the ceramic part Electrodes attached to which electrical signals are applied so that the ceramic element as a lambda / 4-length expandsr oscillates, which works below the sainer resonance frequency. The length changes lead to the vibrating elements to a shift ng of the membrane and to the generation of Sound signal on. The diameter of the membrane is as possible Made big · External is the air pollution in the pressure chamber of the funnel is kept relatively large, eo that the membrane gives the friction element an increased mechanical Resistance is entgager. The selection of the cross-sectional area of the drive element then allows an adaptation of the mechanical resistance between the air and the drive « to produce organ «UJie is explained in more detail below, the form of the frequenzksnnlinis of the loudspeaker becomes through the Uliderstar risk adjustment to the LMngenspander and the air, coupled with tar sr, determined * by use a length expander of the type described the resonance frequency of the same regardless of its cross-sectional area gawihts tuerdan, so that you have a satisfactory resolution of the efficiency and the overall frequency response the 1auteprachar device is possible

The ceramic anti-diabetic seal can take on very different shapes, for example as a hollow cylindrical tube or as a thin flat plate. The flat plate may be rectangular or provided with tapered sides, gsgeschiuindigkeit the Fortpflanzur and thus erhüben vorgsgebsna the length of the ceramic crystal, the upper Grsnzfraquenz for t. Mahrarθ ceramic tiles can be in Dimorph

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Form combined with each other and / ardan, to increase the properties for driving the {membrane available capacity * Czar the crystal and can dam ahman F additionally attenuators be provided, the inclination tu of the crystal to oscillate transversely tu v / erringern to its Längsabsfisseung.

A Trichtariautsp ^ echer with a ceramic crystal drive lens is; in Fig. 1 ga shows. The loudspeaker usually has a round h'nfctofas frame part 12 and a round front frame part 2Λ with a funnel 21 that is widened outward. A rear chamber plate 15 and a clamp 13 are arranged at a distance between the front frame part 23 and the rear frame part 12. The pressure chamber plate 15 presses the JSU imbian 13 against the rear frame part Vibrations of the membrane 13 acting as a piston push air out of the space with the membrane 13 and the plate 15 through openings 22 in the pressure chamber plate 15 and generate sound signals in response.

The rear Rahman: ei :. 12 is provided with a Ts-eibar support plate 24. A ceramic crystal element 14 in the form of a hollow cylindrical tube is arranged for the purpose of the Trsiber carrier plate 24 and the membrane 13. The ceramic crystal element 14 is. at 17 with the driver support plate 24 and 19 connected to the membrane »z. B. glued or cemented. An attenuator 2O ₉ interposed between the Treibar-Trägarplatta 24 un arranged i the Keramiksiament 14 "supports the crystal ztdschsn the points 17 and 19 off to the inclination of the El jmsrits 14 to Sohujingungan transversely to its Längsabmassung to / srringarno wires 16 and 18 are connected to an anechoic valve 25 and electrodes 26 and 27 on the outer and inner surface of the element 14 (Fig. 2) in order to apply signals to the crystal which cause the crystal to vibrate in the form of a long-term tension 27 is directed in such a way that its correct poiarisia * and the ceramic tube become longitudinal shiingings

leads. The ceramic element 14 is present as a drive element for öinu iSteinbr ^ n illustrates that at a Pressure chamber-funnel sprayer is provided instead can daa element Ii au-h for the drive of a different kind Loudspeaker membrane to serve »for example a paper cone.

The ceramic Kristalleleraeni 14 öitd at a frequency betti just ₉ below eairiar resonant frequency is "His length ADRD ds forth equal to the lambda / 4 UJellenlänge at a frequency corresponding to the highest frequency made" which is to uardsn udadergegaban ".A dafübarliegenda frequency uiird called Grenzfrequsnz , since the output signal of the ceramic element drops by 1% (due to the capacity of the element) »manr fractions are applied to the crystal» which are greater than dx 3 resonance fractions. The UJideretand of the ceramic part steadily with decreasing frequency gradually increases, so that a lower Granzfraquana: of the loudspeaker obtained electrical / coupling network required »

The uiirksaine longitudinal the crystal alamants 14 is through the The mass is connected to one end with the membrane and through the glue is used to reduce the amount of putty Crystal with the membrane 13 and the Trsiber carrier plate connected is. As a result, the effective length of the Element 14, which is used to set the limit frequency of the loudspeaker used. uii? df etuias lower than the physical Length of the ceramic crystal itself. Belspielsuieise became with a crystal »with which the cutoff frequency 12, S kHz are eollba, the actual lambda / 4 length for this frequency of S.71 ent with consideration of the fflasss of the adhesive or Zenants and the JHsmbran to 5.60 cm

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decreased. The ud.r <satie length of the 5.71 cm crystal morde thus the above base. 5.60 cm. By “that -the The pale of the ceramic ring 14 is large compared to the eyelet of the Membrane is made »and the influence of the membrane is reduced.

The diameter of the membrane 13 is relatively large. (Int comparison 2u fillers, which are generally used for funnel loudspeakers are provided). Xn the present specially considered on! '"all it consists of aluminum peened with an effective Ko Lbandurchrtiasöer of about 34.9 Run. The membrane is also elliptically shaped »so yours Rigidity does not increase and is not undesirable Way, you can oil the pipe through the fitting 14 is operated as a piston. Ee is also possible «the Size of the pressure chamber between Itlambran 13 and the Druckkamtnerplatta 15 decrease by increasing the distance between These parts are hidden. In the example at hand the distance is 0.03 m «i. Slides increased along with one large diameter of the membrane 13 the mechanical resistance, eo that the coupling to see the air and the mechanical Tube 14 ulideretand improved luird. The mechanical one Ulideretand of the drive elements can be independent of the in First and foremost, the resonance frequency determined by the dimensioning This means that the cross-sectional area is changed. Element 14 is in the array According to Fig. 1 ale tube designed to achieve a desired mechanical To achieve rigidity and at the same time to ensure a relatively small cross-sectional area »around the reduce mechanical resistance of the element 14 and closer to the adaptation .with the membrane loaded by air to approach.

Since the rod element 14 is capable of resonance, as speaks for its resonancefroq jan: i pronounced on «It is however in

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_'s ε ο that the funnel other with him speaker together used or other criteria * frequency ranges unc the inclination of the Frequenzkennlinis influence to "the ear to different frequencies close fit, for example, the response, kanne ground generally desired, the width of the exploitable transmission" The The inclination of the frequency characteristic and its maximum amplitude can be set according to the load on the drive element, so that in practice the quality Q under load is much lower than the quality Jm in the free-looking state. So the magnitude of the greatest amplitude of the frequency response is also ade the shape of the inclination of the frequency response ^ when approaching this maximum frequency is a function of the magnitude of the load on the drive elements 14 "Ee it results that the frequency response can be reduced and broadened in amplitude" by the cross-section & area of the drive element 14 is reduced * the area of the iftambien 13 is increased or the pressure cararaer spacing is increased. between the membrane 13 and the pressure chamber plate 15 is reduced

It is also possible; the drive element 14 from iflagnetostrictive Material to manufacture · Such a driver uiürda driven by means of a magnetic coil such that its length varies depending on the sound signals. A permanent magnet aligned and coupled with the rod 14 in length would serve ale mac netIsche "bias" to a Avoid doubling the frequency.

Fig. 3 shows another embodiment of the invention, at which the Kristallelan ent 13 is auegebilden as a thin plate, which is shown in Fig. 3 in a Kartsnansicht. Electrodes 31 and 32 are arranged on opposite sides of the plate and via wires 33 and 34 to the electrical signal source tied together. The ends 36 and 39 of the Karamischsn crystal 30 are corresponding to the oaths of the hollow cylindrical tube

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according to the figures. 1 and 2 with the Traiberträgerplatte 24 bzu ». the ISaebran 13 glued or cemented. That to the electrodes 31 and 32 applied electrical signal generated in the Crystal 30 a field that uses the crystal as a length expander vibrate 130t and thus the membrane 13 is set in vibrations.

Fig. 4 shows a bet Aueführungeform, of the ceramic, mix crystal bsi 40 tte form of a thin flat plate has "tunz whose strings in Riet, to which the membrane nut dee 13 end connected Krist ropes tapered öiiid so that the surface of the plate from the Treitier carrier plate 24 to fiiambran 13 decreases. The ends of tee Krist ceramic members 40 are connected at 43 with the driver 24 and TrMrerplatte hei 42 with the membrane 13 »z. B. glued. An electrode 41 is arranged on one surface of the crystal 40. Another electrode, not shown, is on the opposite surface, wires 45 and 46 are connected to the electrodes to apply the electrical signal to them An electric field is created in the ceramic crystal 40, which causes the crystal to oscillate as a length expander and in this way sets the membrane 12 to oscillate.

Fig. 5 shows an embodiment in which the crystal SO is exponentially tapered so that the area of the plate decreases exponentially. The ends of the crystal 60 are connected at 63 to the driver Träcerpiatte 24 and at 62 to the membrane. An electrode 61 is arranged on one surface of the crystal 40, while another, not illustrated electrode is provided on the opposite surface. Wires 55 and 66 are connected to the electrodes. The electrical sign applied to the electrodes through these wires ?! If an electric field is created in the crystal 60, the crystal is looped as a length expander and the membrane 13 is then quietly set in vibration.

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The tapering of the strings of the ceramic crystals 40 and 60 in the described manner leads to an increase in the propagation gas strength of the pressure wave within the crystal and results in a higher frequency of lasing for a given crystal length. This form of training totality && _t dia 'Itav.zf frequency of the system uieiter upwards to echisbestj without reducing the length of the ceramic crystal * Instead of the linear and exponential tapering shown in FIGS * that lead to the desired results »z. B-. Graduated Uarjüngungan odsr 'ier / üngungen like an Eaussian curve,

Figure 6 shows a AusrPührungsfarm represent invention, bai a plurality wan Cri;? Tallsn 5O ₉ dia dutch electrodes 51 and 52 are separated ₅ Ln I Iciorphar Fattn are attached ansiinandar. Elektrodsn Si., And 54 are on the outer surfaces of the Krietallpakats ang Jortinet. The electrical signals are applied via wires 55 and 56 to the electrodes 51, 52, S3 and 54. Dia Polari 5ia: - excitation of the crystal 50 and the excitation of the electrodes so that the length of each crystal is in the same direction as that changes the adjacent crystal, when the electrical signals are applied to the crystals * This embodiment allows a drive of the .lemhran 13 with greater force than would be possible as a crystal by means of einsig _o

fflit the invention uirc; a simply constructed speaker system created dah a modifiable in Seinan dimensions driver varui changes. The driving force acts as a length expander and is directly coupled with the language armambran. The loudspeaker outputs a frequency band with minimal interference and without any electrical output. kopplungsnetzuierka are required ο The manufacturing costs are cheap.

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Claims (9)

Claims Electroacoustic transducer with a frame and one of the frame mechanically supported membrane, characterized by an elongated, in its longitudinal dimension through applied electrical signal changeable drive member, one end of which with the frame and the other end. is connected to the membrane and the length of the sine is such that at one? Frequency in the upper frequency range of the Sound energy lambda / '4 resonance occurs. 2. Converter according to claim 1, characterized in »that the Drive member a tube (i4) made of piezoelectric material is. 3 · converter according to claim 2, characterized by on the Electrodes attached to the inside and outside of the tube (14) (26.27). 4. Converter according to claim 1, characterized in that the Drive organ a 3 PJette (40,60) with tapering Is rare. 5. Converter according to claim 1, characterized in that the Drive member a-a plate (60) with exponentially tapering Pages is « 6. Converter according to one of claims 1-3, characterized in that » that with the help)) of the cross-sectional area of the pipe (14) the resistance of the drive organ to that of the membrane is adapted. 7. Converter according to one of the preceding claims, characterized characterized in that the membrane (13) has an elliptical cross-section. 8. Converter according to one of the preceding claims, characterized 909806/0505 marked that with the help of the height UIf ulideretand adaptation to the previous 14Üft is taken. '■ -! * · ■ ■ · -. ' 9. Tiiandler according to one of the preceding claims ', characterized in that the membrane (13) riii ^ einaw hoehftii' quenten ichallaitenden hern (21) geko ^pfli i # t « . ".." ■■■ α -. "■ * 909806/0505 SAO ORIGINAL