EP1506691B1 - Loudspeaker - Google Patents

Abstract

An inventive loudspeaker includes a diaphragm, a first excitation means for generating structure-borne sound in the diaphragm, and a second excitation means, different from the first one, for setting the diaphragm into a longitudinal vibrational motion in a direction perpendicular to the extension of the diaphragm. In accordance with the invention, the problem of insufficient bass reproduction and/or of the magnitude conflicting with invisible integration or installation is solved in that a second exciter system is introduced, which uniformly moves the diaphragm, or the plate serving as the diaphragm, forward and backward in addition to the bending waves of the structure-borne sound. The sound reproduction therefore is possible across the entire audio-frequency range without impeding the goal of invisible integration or installation.

Description

The present invention relates to speakers and in particular on flat speakers or flat-sound transducers.

The emerging trend in consumer electronics trend making smaller and more compact components as well not stop in front of the speaker technology. The trend is even so far that speakers are not just more small, but also for the listener "invisible", i. for the eye of the Listener should be hidden. Especially for multi-channel playback, like surround, and wave field synthesis (WFS) is the possibility of invisible installation of large Use. The number of individual channels required here and thus speakers quickly extends to over 50 Piece. But such playback systems are also for home use developed and offered, and thereof must be assumed that the customer, for example, for a WFS system his living room for reasons of space not with 50 conventional speakers want to have alternative Speakers are used.

The goal is to construct speakers so that they themselves can be integrated into other appliances or furniture so that distribute the same unobtrusively in the room in this way to let. For example, there are already speakers that at the same time as a picture frame, as a screen or even act as a cabinet door.

For the technical realization of these "hidden" speakers the cone speaker is not suitable because he due to its membrane shape is not flat enough. Better suitable is a speaker whose membrane from the outset flat as a plate is and its electro-acoustic Exciter system has the smallest possible dimensions. This Principle, namely the use of a plate as a membrane in Connection with the use of a pathogen system is already in DE 465189 published in 1929 and its additives DE 484409 and 484872 for an acoustic window display used. There was a windowpane a shop window as a membrane, which by a attached electrodynamic excitation system for sound reproduction was stimulated.

The principle of this principle function mechanism consists in that one to the electrodynamic excitation system applied electrical signal into an audio-frequency mechanical Vibration is converted. This mechanical Vibration is at an excitation point, at which the pathogen system abuts the membrane or attached to the same is transferred to the serving as a membrane plate, whereby structure-borne noise is generated in the plate. Especially the structure-borne sound component, which is determined by bending waves spread in the membrane, ensures the production of airborne sound.

In this loudspeaker principle, the generation of Airborne noise therefore takes place via the detour of structure-borne noise. The longitudinal mechanical oscillations of the Oscillation pulses of the pathogen system are not as in Cone speakers taken from the diaphragm and immediately in Airborne sound implemented, but it will initially be structure-borne noise produced in the membrane, the - and in particular the bending shaft portion same - then the surrounding air to longitudinal waves or pressure waves, i. Sound, stimulates. The Transformation of structure-borne sound plays like this a filter in the signal chain. The result is that only one person Signal component of the signal to be reproduced as airborne sound is reproduced in the plate as structure-borne sound spread out and then radiated into the room can.

Since, as already mentioned, that body sound component, the propagates in the form of the bending wave, the largest contribution to produce airborne sound by means of a plate membrane, have the characteristics of the bending wave, in particular their stimulation and their spread, decisive influence on the construction of a flat speaker according to the bending wave principle. Taking these properties into account itself, that for a broadband sound reproduction membrane plates with low weight and large dimensions necessary. The required plate size is now but again the goal of the invisible integration of the Speaker in the area of the listener in the way. So is even with relatively large plates, the reproduction of the frequency range below about 200 Hz of worse Quality. The reason for this is that a plate only in their eigenmodes with their associated natural frequencies oscillates and for the sound reproduction the fashion density, i.e. the number of modes per frequency range, crucial is. Below 200 Hz is a sufficient mode density so far, however, has not been achieved.

Thus, there is a need for a speaker, on the one hand accessible to invisible integration, i. flat and small is implementable, and the other not only in the middle and high frequencies but also in the Low frequency range allows a satisfactory sound reproduction.

DE 19541197 A1 describes a cone loudspeaker with an electrodynamic vibration system, a cone-shaped Membrane, a bead and a basket on which the membrane is hung over the bead. When applying a sound signal to the vibration system, the membrane performs a Lifting movement along the center line. The membrane is with a layer of a piezoelectric material provided which is also connected to the sound source and while undergoing expansion changes. Depending on whether the Layer is connected to another layer or one bimorph arrangement of two oppositely poled and with each other glued longitudinal or radial oscillator plates is, the layer acts as a thickness oscillator or bending vibrator.

DE19960082A1 describes a loudspeaker with a Plate diaphragm attached to its back by a vibration drive is operated. The plate membrane performs at the oscillation a lifting movement.

The documents US 2002/0027999 A1 and DE 199 55 867 A1 describe speakers in which plates are used both as a vibrator and pistonically.

The object of the present invention is to provide a To create speakers that are better at fixed size Playback quality or a fixed playback quality more compact design allows.

This object is achieved by a loudspeaker according to claim 1 solved.

A loudspeaker according to the invention comprises a membrane, a first excitation device for the excitation of structure-borne noise in the membrane and a second, different from the first, Excitation device for displacing the membrane in a longitudinal oscillatory motion in the direction perpendicular for membrane expansion.

According to the invention, the problem of low bass reproduction on the one hand and invisible integration on the other On the other hand by installing or installation opposing size solved that introduced a second pathogen system which is the membrane or serving as a membrane Plate in addition to the bending vibrations of structure-borne noise uniformly moved back and forth. The sound reproduction is thereby over the entire hearing frequency range possible without the goal of invisible integration or installation is hampered.

In other words, the core idea of the present Invention in that a broadband playback means a compact speaker can be obtained that of a membrane and associated exciter consists of two different to excite the membrane Excitation devices are used, which are the membrane vibrate in different ways and responsible for different frequency bands or frequency ranges are. The one, already known arousal device for generating structure-borne noise in the membrane is according to the invention only for the reproduction of the high and Mitteltonbereiches responsible and their task is only in it, as many bending waves in the membrane to stimulate. The previously missing low frequency range takes over the exciting device added according to the invention, the the membrane to longitudinal forward and backward swinging movements stimulates with a big stroke. Contrary to the sound generation the structure-borne sound excitation device becomes the membrane from the inventively introduced second excitation device excited to longitudinal vibrations, thereby The membrane thus oscillates in the form of bending waves and in addition as a whole uniformly back and forth emotional.

The deflection of the second exciter can far be greater than the bending waves of the structure-borne sound generating device. Because the diaphragm is a relatively large fictitious Membrane surface possesses, by the uniform Moving the plate back and forth moves a lot of air volume. In this way, the generation of sufficient sound level in the low frequency range much better possible than with the Bending shaft principle, in which the diaphragm deflections also can be smaller.

An advantage of the present invention is again in that by the combination of both types of excitation, i.e. structure-borne sound generation and the longitudinal and backward motion, on a membrane one clearly better reproduction of the entire hearing frequency range is possible.

Due to the possibility of a larger diaphragm stroke in the Low frequency range by the exciting device according to the invention for displacing the membrane into a and backward motion, the membrane surface may contribute Consistent playback quality are reduced. in the In contrast, need flat speakers, only on the Structure-borne sound generation based, a very large membrane area, to generate enough sound in the low frequency range, because of the small diaphragm stroke of the bending waves by a As large membrane area must be compensated to to achieve the same volume displacement, allowing conventional Flat speaker must be relatively large. Consequently, there is an advantage of the present invention also in that a speaker according to the invention due to its compactness better for an invisible integration or installation is suitable.

Conversely, there is an advantage of the present invention in that with the same membrane size due to the Combination of the two excitation means the woofer reproduction is significantly improved. The advantage of the invisible Integration or installation becomes thereby not canceled but by a better playback quality added.

Another advantage of the present invention is in that by the fact that the longitudinal oscillatory motion a lot of air volume moves, the bass reflex principle is effective can be used, which in previous flat speakers after Flexural wave principle to no improvement of the bass tone generation led.

Another advantage of the present invention is in that, since the reproduction in the low-frequency range by the Generation of forward and backward oscillations of the membrane is taken over, the structure-borne noise generating device even after the piezoelectric principle can work, what so far when using only the structure-borne noise generation due to the very narrow frequency range for which the piezoelectric principle is suitable, only with losses the bandwidth was possible. By combining with the additional excitation system for longitudinal vibration movement The membrane thus becomes a significant improvement achieved in the sound reproduction, so that the structure-borne sound generating device after the piezoelectric Principle can work.

Fig. 1a

eine schematische Teilschnittseitenansicht eines Flachlautsprechers gemäß einem Ausführungsbeispiel der vorliegenden Erfindung, wobei lediglich die als Membran dienende Platte zusammen mit der Körperschallerzeugungseinrichtung ohne die Longitudinalschwingungserregungseinrichtung gezeigt ist, wobei auch das Schwingungsverhalten der Membran, d.h. die durch die Körperschallerzeugungseinrichtung erzeugten Biegewellen, angedeutet sind;

Fig. 1b

eine schematische Teilschnittseitenansicht des Lautsprechers von Fig. 1a, wobei lediglich die als Membran dienende Platte sowie die Longitudinalschwingungserregungseinrichtung und nicht die Körperschallerzeugungseinrichtung gezeigt ist, wobei auch das Schwingungsverhalten, d.h. die Vor- und Zurückschwingungsbewegung, der Platte aufgrund der Longitudinalschwingungserregungseinrichtung angedeutet ist;

Fig. 1c

eine schematische Vorderansicht des Lautsprechers nach Fig. 1a und 1b;

Fig. 1d

eine schematische Teilschnittdraufsicht eines Lautsprechers, in dem die Longitudinalschwingungserregungseinrichtung nach Fig. 1b und die Körperschallerzeugungseinrichtung nach Fig. 1a zu einem Lautsprecher kombiniert sind;

Fig. 2a

und 2b eine schematische Vorderansicht und Teilschnittdraufsicht eines Lautsprechers gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 3

eine schematische Teilschnittdraufsicht eines Lautsprechers gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 4

eine schematische Teilschnittdraufsicht eines Lautsprechers gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 5

eine schematische Teilschnittdraufsicht gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung; und

Fig. 6

eine Teilschnittdraufsicht eines Lautsprechers gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung, wobei lediglich die Körperschallerzeugungseinrichtung und nicht die Longitudinalschwingungserregungseinrichtung gezeigt ist.

Further preferred embodiments of the present invention will be explained in more detail below with reference to the accompanying drawings. Show it:

Fig. 1a

a schematic partial sectional side view of a flat speaker according to an embodiment of the present invention, wherein only serving as a diaphragm plate is shown together with the structure-borne sound generating device without the longitudinal vibration excitation means, whereby the vibration behavior of the membrane, ie the bending waves generated by the structure-borne sound generating means are indicated;

Fig. 1b

a schematic partial sectional side view of the speaker of Figure 1a, wherein only serving as a diaphragm plate and the longitudinal vibration excitation means and not the structure-borne sound generating device is shown, wherein the vibration behavior, ie the forward and backward swinging motion, the plate is indicated due to the longitudinal vibration excitation means.

Fig. 1c

a schematic front view of the speaker of Fig. 1a and 1b;

Fig. 1d

a schematic partial sectional plan view of a loudspeaker, in which the longitudinal vibration excitation device of Figure 1b and the structure-borne sound generating device of Figure 1a are combined to form a loudspeaker.

Fig. 2a

and Fig. 2b is a schematic front view and partial sectional plan view of a loudspeaker according to another embodiment of the present invention;

Fig. 3

a schematic partial sectional plan view of a loudspeaker according to another embodiment of the present invention;

Fig. 4

a schematic partial sectional plan view of a loudspeaker according to another embodiment of the present invention;

Fig. 5

a schematic partial sectional plan view according to another embodiment of the present invention; and

Fig. 6

a partial sectional plan view of a speaker according to another embodiment of the present invention, wherein only the structure-borne sound generating means and not the longitudinal vibration excitation means is shown.

Before the present invention with reference to the Drawings are explained in more detail, it is pointed out that same or functionally identical elements in the drawings provided with the same or similar reference numerals are, and that to avoid repetition in the description the figures a new explanation of these elements is omitted.

The general principle will first be described with reference to FIGS. 1a-1d the present invention using an exemplary embodiment for a speaker explained in more detail. The speaker, generally indicated at 10, consists essentially from a serving as a membrane plate 12, a Structure-borne noise generating device 14, a longitudinal vibration excitation device 16 and an excitation signal generating means 18th

The structure-borne sound generating device 14 operates according to the electrodynamic principle and is more detailed in Fig. 1a shown in cross section. The structure-borne sound generating device 14 includes an annular permanent magnet 20, which is polarized along its axis of rotation, a centered or coaxial with the annular permanent magnet 20 arranged cylindrical pole core 22 and a in an annular air gap between pole core 22 and permanent magnet 20 extending voice coil 24. Beyond can the structure-borne sound generating device formed as an electrodynamic drive 14, for example, disk or annular pole plates. Of course, one is Another structure of the electric motor drive also possible. The consisting of the voice coil 22 part on the one hand and the pole core 22 and the permanent magnet 20 existing part of the structure-borne noise generating device 14 On the other hand, they are mutually displaceable. The thus formed Structure-borne sound generating device 14 is on the Voice coil 22 containing part centered on the plate 12 attached. As it is described below, is the opposite case, however, also conceivable. Otherwise is the structure-borne noise generating device not fixed or unlicensed, i. the other from components 20 and 22 existing part, is freely movable.

In the present case, the membrane 12 is exemplified as perpendicular Membrane 12 has been described, to which a coil 24 attached is that in an annular air gap between a cylindrical Polkern 22 and an annular permanent magnet 20th immersed, wherein Polkern 22 and permanent magnet 20 a Form unit, which is guided via the voice coil 24 to opposite the same in the direction perpendicular to the expansion direction the diaphragm 12 to be displaced. The vertical For example, membrane is part of a wall. In this vertical Alignment acts on the non-retained part 20, 22 of the drive 14 no force in the direction of the surface normals of the Membrane 12 has, i. in the direction in which this part is relative to the voice coil 24 is displaceable, but only the downward weight. Without applying the excitation signal Consequently, there is no reason that the part 20, 22 is omitted. In addition, this part naturally has a certain inertia, so that the excitation device 14, which is provided for, To produce structure-borne noise in the membrane 12; so mechanical Waves in the lattice of the membrane 12, which spread in it, high frequency is excited, and that with sufficient inertia or sufficient weight of the freely movable part 20, 22 of the Drive compared to the inertia or the weight of the membrane 12 this part will essentially not leave its position, but rather only the voice coil 24 together with the membrane 12 is moved back and forth within the air gap and while still keeping the floating part 20, 22 from to be pulled down by gravity. factors such as the elasticity of the membrane material play a role in how much the membrane 12 and thus the Voice coil 24 is deflected, so that a slide out of the Voice coil 24 from the air gap of the exciter 14th can be prevented with appropriate consideration. Furthermore still has to by the longitudinal vibration excitation device 16 caused stroke to be considered to pull out the coil out of due to the inertia of the freely movable Partly quasi-stop gap to prevent. This can be done, for example, by appropriate length of the overlap from coil 24 and air gap done. In addition, a elastic connection of the two slidably slidable against each other Parts of the drive 14 may be provided, so that the freely moving part in case of vibrations together with the membrane and the part attached to the same is moved, and by higher-frequency relative movements to the attached part still structure-borne noise generated in the membrane.

Of course, a speaker of the type shown in be attached to another position, such as on the ceiling. Then However, additional measures should be taken to that the moving parts of the drive 14 with each other coupled, such as e.g. in addition to the mechanical air-gap voice coil guide via an elastic connection, so that the two moving parts of the drive 14th alone already form an oscillatory system and one Sliding down the freely movable part of the drive 14th is prevented from passing through the coil 24.

The electrodynamic drive 14 converts an electrical Excitation signal flowing through the voice coil 24, after the electrodynamic principle in a mechanical relative motion between the two parts, the at the Plate 12 attached and free to move. Of the freely movable part advantageously has enough Inertia, to the mechanical relative vibration movement effectively to transfer to the plate 12, whereby in the Plate 12 structure-borne noise and in particular bending waves generated be as exaggerated in Fig. 1a. The Excitation signal flowing through the voice coil 24, receives it from the excitation signal generator 18, the same turn from an electrical sound signal generates the information to be reproduced displayed in a suitable manner.

The longitudinal vibration exciter 16 also works according to the electrodynamic principle and is shown in Fig. 1b shown in cross section. The longitudinal vibration excitation device 16 is coaxial with the structure-borne sound generating device 14 arranged. The electrodynamic Drive of the longitudinal vibration excitation device 16 Also includes a permanent magnet 30, a pole core 32 and a voice coil 34. The voice coil 34 receives her electrical excitation signal also from the excitation signal generating means 18, the same of the same the information to be displayed indicating sound signal generated. The part surrounding the voice coil 34 touches the plate 12 - or is connected to the same - via a Adapter 36. In other words, the voice coil 34 firmly connected to the adapter 36, extending from the Voice coil 34 extends from in the direction of the plate 12 and it expands radially to the plate 12 at rest of the speaker 10 along an annular excitation region either with a certain diameter or attached, such as glued to be, and around with the plate 12, the structure-borne sound generating device 14 to surround. In particular, the adapter 36 consists of a cylinder jacket 38 with a diameter that is one tenth of the Extending the plate 12 at the narrowest point, and webs 40 extending radially and connect the cylinder jacket 38 to the voice coil 34, such that the cylinder jacket 38 is coaxial with an excitation point is aligned, on which the mechanical Vibration of the structure-borne sound generating device 14 on the Plate 12 is exercised.

The adapter 36 need not, as shown in Fig. 1a-1d, a circular cross-section or a circular excitation region have and be formed as a ring adapter, but may for example be formed rectangular. The extent of the excitation range is, for example between one-tenth and new tenths of the extent the plate 12 in the respective direction of expansion of the Plate 12. The adapter 36 allows the mechanical Oscillation of the drive 16 to a longitudinal oscillatory motion the plate 12 almost in the whole, so translational, leads, as will be explained in the following. Due to the coaxial or centrally symmetrical structure the influence on the longitudinal vibration exciter is reduced 16 through the excitation area or bearing area on the of the structure-borne sound generating device 14 generated bending waves, which approximated isotropic from the coaxial excitation point of the Body sound generating device 14 spread, exercises.

Along the bearing surface of the adapter 36 supports be arranged by the adapter 36 in the direction of Project plate 12, so that the adapter 36 only on isolated Support points, i. the ends of the columns, on the Plate 12 rests or is fixed there. This can the influence of the adapter 36 and the longitudinal vibration excitation device 16 on the generated structure-borne noise be further reduced without significantly the uniformity the drive of the longitudinal vibration excitation device 16 impair.

During the existing of the voice coil 34 part of the electrodynamic drive of the longitudinal vibration excitation device 16 via the adapter 36 with the plate 12th coupled, or, by docking, is the other, consisting of the magnet 30 and the pole core 32 existing Part fixed in place, such. on a back wall of the speaker (not shown) attached. That way is the power transmission of the longitudinal vibration excitation device 16 generated on mechanical vibration the plate 12 is larger than in the structure-borne sound generating device 14th

After in the previous the construction of the loudspeaker of 1a-1d is described below Function described. To get the electrical tone, which indicates the information to be reproduced, in airborne sound in the form of longitudinal waves or pressure waves, the speaker 10 comprises the two devices 14 and 16. Both institutions 14 and 16 take over the Play the information to be played back for different Frequency ranges or frequency bands. The structure-borne sound generating device 14 is for playback the high and midrange areas, while the Longitudinal vibration excitation device 16 for the Low-frequency range is responsible. Although it is possible that electrical sound signal to the electrodynamic drives of both Facilities 14 and 16 and thus the two the same Excite signal, whereby the device 18 would be unnecessary, it is preferred that the same different excitation signals are supplied, which differ with respect to the frequency band and optimally to the respective work area of the facility 14 and 16 are adapted. This gives the device 14 a higher frequency portion of the audio signal than the device 16. The frequency range of the excitation signal for the structure-borne noise generating device 14 extends for example, from 100 Hz to 25 kHz and preferably from 150Hz to 20kHz, while the frequency range of the excitation signal for the longitudinal vibration excitation device 16, for example, from 10Hz to 2kHz and preferably from 20Hz to 200Hz. For this purpose, the excitation signal generating device 18, for example, as a crossover be executed. In general it is therefore advantageous if the frequency range for structure-borne sound generation a frequency higher than all of the frequency range included to the longitudinal vibration excitation Frequencies, or the frequency ranges include a first Frequency at which the excitation signal for structure-borne sound generation is higher than the other excitation signal, and one second, to the first lower frequency at which the excitation signal for longitudinal vibration excitation equal to the other excitation signal or higher than the same.

The generated by the excitation signal through the voice coil 24 mechanical oscillations lead in the Plate 12 to structure-borne noise in the plate 12 and in particular to bending waves, in turn, at the interface air-plate be converted to airborne sound. The structure-borne sound generating device 14 has this advantageously a sufficient moment of inertia.

The longitudinal vibration excitation device 16 offset the plate 12 in longitudinal oscillatory movements 42 with a hub which is significantly larger, e.g. more than 20 times greater than the amplitude of the structure-borne noise generating device 14, e.g. 20mm. This longitudinal Back and forth movement 42 of the plate 12 leads directly to longitudinal airborne sound waves or pressure waves 44 in Low frequencies. Around the big stroke of the longitudinal vibration excitation device 16 allow without by the mass of the drive of the longitudinal vibration excitation device 16 the voice coil 34 is no longer vertical in the field of the air gap can dip and thus distortions arise is the longitudinal vibration excitation device 16 with the magnet 30 and the pole core 32nd fixed part of the drive, such as. at a Back wall. The adapter 36 serves to mechanical Oscillation movement of the voice coil 34 so on the Distributed plate 12 to transfer that the plate 12 in im essential translational oscillatory movements in Direction perpendicular to an extension direction of the plate 12 is excited, i. the plate as possible in whole before and swing back. The plate 12 thus vibrates in itself in the form of bending waves, as shown in Fig. 1a, and in addition, as a whole, uniform back and forth as it is shown by the double arrow 42 in Fig. 1b.

Although it would be possible, the plate 12 only via a firm connection through the adapter 36 with the voice coil 34 comprehensive part of the drive of the longitudinal vibration excitation device 16 and the leadership of this Partly in which the permanent magnet 30 and the pole core 32nd comprehensive part, such as when attaching the Loudspeaker hanging down on the ceiling, it is preferred if in addition a holder for the Plate 12 is provided, as in the following embodiments the case is. Although it is also possible is the translational longitudinal vibration movement 42 the plate 12 only via the electrodynamic drive it is preferred that the plate 12 be such is suspended or stored oscillatory that at a longitudinal translation of the plate 12 from a rest position the same in the direction perpendicular to the plate extension a force caused by the suspension of this translational Deflection counteracts the membrane in the rest position return. In this way form suspension and plate 12 an oscillatory system in which the plate 12 is capable of translationally moving in the direction perpendicular to the expansion direction to move back and forth. This vibration system should be designed for a natural frequency be close to the bass range, for the longitudinal vibration excitation device 16 is responsible for exploiting the resonance overshoot.

In the following, various embodiments will be described, based on which different possibilities for the suspension of serving as a membrane plate for the Attachment of the longitudinal vibration excitation device as well as for the positioning of the same on the plate become.

Fig. 2a and 2b show an embodiment of a Speakers in which as the only differences to the Embodiment of Fig. 1a-1d, the longitudinal vibration excitation device from four electrodynamically working Drives 16a, 16b, 16c and 16d, and as Membrane serving plate 12 via a spider 50 on a Frame 52 is suspended, which in turn on a rear wall 54 is attached, which in turn also the the Permanent magnet 30 and the coil core 32 comprising part the electrodynamically operating drives 16a-d attached is.

The spider 50 is attached along the circumference elastic bands 56, e.g. Rubber bands, which themselves from their attachment ends on the circumference of the plate 12 in the essentially star-shaped from the center of the plate 12 to Extend the outside to point the way to the other end of the Frame 52 to be attached. The bands 56 are relative to their attachment and spring constants designed so that each edge piece is equally affected. By the Attachment of the drives 16a-16d on the rear wall on the one hand and the suspension of the plate 12 via the spider 50 on the other the danger is averted that by the mass of the Drives 16a-16d the voice coil 34 of the same no longer can dive vertically in the field of the air gap and thus distortions arise. The serving as a membrane Plate 12 and the drives 16a-16d are assembled Preferably adjusted so that none the direction of movement of the other. In this way, the membrane or plate mass and the mass of the longitudinal vibration excitation device 16 no influence the direction of vibration of the excitation coils 34 of the drives 16a-16d. The spider 50 takes over the function of a bead, which dampens the membrane or plate 12 after each deflection and returns to the starting position or rest position. The Rear wall 54 may serve as part of a speaker enclosure. However, the provision of a speaker enclosure is not mandatory. Due to the central symmetric arrangement 16a-16d drives are the fault, the same by their contact or connection to the plate 12 at the excitation points on the bending waves caused by the Structure-borne sound generating device 14 are generated, exercise, reduced. The excitation drives (16a-16d) become in phase either from the same excitation signal driven or by those that differ in terms of amplitude differ to edge effects of the membrane plate 12th compensate.

Referring to Fig. 3, an embodiment for a speaker that is different from the speaker 2a-2b differs by another suspension, but also a translational longitudinal Oscillation of the membrane serving as a plate 12 forward and back to a rest position allows. In this Embodiment, the diaphragm 12 is resilient on each one axis 60 per corner of the rectangular, serving as a diaphragm Plate 12 stored. The axes 60 are fixed to the Rear wall 54 attached to which also the drives 16a-16d are attached, wherein the axes 60 perpendicular from the parallel protrude to the plate 12 extending rear wall 54, i.e. in the direction of that caused by the drives 16a-16d translational longitudinal vibration direction extend. The storage of the plate 12 at each corner is for example, by a corresponding hole on each corner realized, through which the respective axis 60 extends. A resilient mounting of the plate 12 at each corner on the axes 60 is through, for example, coil springs 62nd achieved, which surround the axes 60, led by the same be and attached to the respective corner of the plate 12 End and a fixed, for example, with the back wall 54 connected end, have. Of course, too Any other elastic means can be used to define a potential minimum for the respective corner.

Vertical plunging of 16a-16d drives voice coils is also ensured by the suspension of FIG. 3. Furthermore, the assembly is again preferably carried out such that the diaphragm 12 and the drives 16a-16d do not affect each other's directions of movement. As in FIGS. 2a and 2b, the rear wall 54 can be part of it a speaker housing serve. Membrane mass and mass of the longitudinal vibration exciter 16a-d less influence on the vibration direction of the voice coils 34 of the actuators 16a-16d, i. they dive like they do not installed state in the respective air gap. The Springs take on the function of the bead, which is the membrane 12 after each deflection dampens and in the starting position returns.

As already described with reference to Figs. 1a-1d is the part of the drives that surrounds the voice coil the longitudinal vibration excitation device with the Plate 12 either be firmly connected or at the same only present. In both cases it is preferred that when assembling the loudspeaker according to Fig. 2a, 2b and 3 of Distance between the membrane plate 12 and the drives 16a-16d set in the rest position of the membrane plate 12 such that they are touching, but at rest they do not exert any forces on each other. In order to the membrane plate better suits the movements of drives 16a-16d can follow, which is the voice coil 22 and 34 comprehensive Part of the same preferably with the plate 12, for example bonded.

4 shows an embodiment of a loudspeaker, in which, in contrast to the speaker of FIG. 3 the the longitudinal excitation device forming drives 16a-16d not over the voice coil 34 comprehensive Part, such as via a vibration coil carrier on the Membrane plate 12 are attached but over the permanent magnet 30 comprehensive part of the electrodynamic excitation system. The voice coil 34, however, is on the back of the speaker 54 and not attached to the membrane plate 12. For the vertical immersion of the voice coil 34 in the air gap between the permanent magnet 30 and pole core 32nd continues to provide the suspension, i. the axes 60 with the Springs 62 and the spider 50th

5 shows an embodiment of a loudspeaker, in which, as in the previous embodiments, both exciters 14 and 16 after the electrodynamic Working principle, however, the electrodynamic Drive of the longitudinal vibration excitation device 16 as a magnet, the permanent magnet of the structure-borne noise generating device 14 used. Regarding suspension and structure-borne sound generating device 14 corresponds the embodiment of Fig. 5 that of Fig. 3rd and 4. In contrast to the embodiments of FIG. 3 and 4 includes the longitudinal vibration excitation device 16 but only one coaxial with the voice coil 24 of the drive of the structure-borne sound generating device 14 arranged voice coil 70 which is attached to the rear wall 54 is. Both voice coils 24 and 70 act with the same Permanent magnet 20 together. In this construction In addition, another pole core around the voice coil 70th be provided. The voice coil 70 thus surrounds the structure-borne noise generating device 14. So also with the Embodiments of Fig. 2a, 2b and 3 is the the Voice coil 70 comprehensive part of the drive of the longitudinal vibration excitation device 16 fixed while the other part is attached to the membrane plate 12, present namely the permanent magnet 20 of the structure-borne noise generating device 14. The drive of the structure-borne sound generating device 14, however, is only on the plate 12th fastened, namely with the vibration coil 24 comprehensive Part.

Fig. 6 shows an embodiment for a special attachment the structure-borne sound generating device 14 at the as a membrane serving plate 12. Instead of as in the preceding Examples of attachment of the voice coil the membrane plate 12 via an annular vibration coil carrier on an excitation area is in the embodiment 6, a voice coil bobbin 80 is provided, which carries the voice coil 24 and on which the membrane plate 12 facing side a conical part having the cone tip connected to the membrane 12 is. This is an optimal point excitation as Membrane serving plate 12 to bending waves and a higher upper limit frequency of the structure-borne noise generating device achieved.

Finally it is pointed out that it is possible is to produce a speaker according to the invention with housing, in which the serving as a membrane plate via a airtight suspension is suspended on the housing to Completing the housing airtight. In order to make this possible, For example, a special bead may be used, e.g. a continuous, between the circumference of the plate 12 and the scope of a corresponding recess of the speaker strained elastic band. For very heavy membrane plates or combinations of membrane plate and glued Excitation systems, the thickness can be even more by the spring-axle suspension of FIG. 3 or by the spider suspension according to Fig. 2a and 2b are supported. Because of the longitudinal translational movement of the Entire membrane is moved sufficiently air volume can In addition, the bass reflex principle can be used. To becomes a hole for the reflection channel, for example laterally, incorporated into the housing.

It should be noted that, although in the preceding in each embodiment, only a structure-borne sound generating device was provided, also several such Facilities can be used. Here is one Distribution around the center of the membrane plate is preferred. however is both in the case only one and in the case several structure-borne sound generating devices also a decentered Arrangement away from the center possible. The Arrangement should be chosen such that the excitation the bending waves is optimal.

Further, for displacing the membrane plate in longitudinal Forward and backward movements not just one or four drives, but any one Number. When using several such longitudinal vibration drives the same way, advantageously arranged that the membrane plate over the entire surface is driven evenly distributed. For several Drives, the adapter may be missing, as in the examples of Fig. 2-4 is the case. The arrangement of several such longitudinal vibration drives is preferred always center-symmetrical with respect to the membrane plate. By using several longitudinal vibration drives increases the possible sound level of the speaker.

It should also be noted that the above variations the embodiments of FIG. 1a - Fig. 6 as desired can be combined with each other, both in terms on the suspension, the positions of the drives as well the attachment of the relatively movable parts of the Drives.

Further, with regard to the foregoing description Fig. 2a-5 pointed out that instead of the elastic or oscillatory suspension of the membrane plate by the above-described elastic means, i. the elastic bands 56 and the springs 62, also a elastic suspension or attachment of the drives of Longitudinal vibration excitation device may be provided could, while the membrane plate, however, only by the axes 60 is guided or free.

Furthermore, other drives than those in the preceding could be described, drives on one other transducer principle than the electrodynamic principle based. In particular, for the structure-borne noise generation used drive could also be considered after the piezoelectric Principle be executed working, such. as a Piezo crystal connected to the membrane on one side is and on the other hand connected with a weight and otherwise free to move.

Finally, it should be noted that it also it is possible that the structure-borne noise generating device not firmly connected to the membrane, but that they for example, by a suitable device from above hanging at a fixed height, but otherwise in longitudinal Vibration direction of the vertically aligned Membrane is held freely movable to rest at the Membrane to abut.

Claims (19)

1. A loudspeaker comprising
   a diaphragm (12);
   a first excitation means (14) for generating structure-borne sound in the diaphragm (12); and
   a second excitation means (16), different from the first one, for setting the diaphragm (12) into a longitudinal vibrational motion (42) in a direction perpendicular to the extension of the diaphragm, the second excitation means (16) having an electrodynamic drive which comprises a first part comprising an oscillator coil (34), and a second part comprising a magnet (30), one of the first and second parts being attached in a stationary manner, whereas the other part is attached to or contacts the diaphragm (12).
2. The loudspeaker as claimed in claim 1, wherein the first excitation means (14) is configured to operate in accordance with the electrodynamic or piezoelectrical principles.
3. The loudspeaker as claimed in claims 1 or 2, further comprising:

   a means (18) for generating a first electrical excitation signal having a first frequency range, and a second electrical excitation signal having a second frequency range from an electrical signal indicating information to be rendered, the first frequency range including a frequency higher than all frequencies included in the second frequency range, or the first and

   second frequency ranges including a first frequency, where the first excitation signal is higher than the second excitation signal, and a second frequency lower than the first frequency, where the second excitation signal is equal to the first excitation signal or is higher than the first excitation signal.
4. The loudspeaker as claimed in any of claims 1 to 3, wherein the first excitation means (14) is attached to the diaphragm (12), and is otherwise non-attached.
5. The loudspeaker as claimed in any of claims 1 to 4, wherein the electrodynamic drive of the second excitation means (16) is spaced away from the diaphragm (12) by such a distance that in an idle state, the second excitation means (16) and the diaphragm (12) do not exert any forces upon each other.
6. The loudspeaker as claimed in any of claims 1 to 5, wherein the second excitation means (16) is connected to the diaphragm (12).
7. The loudspeaker as claimed in any of claims 1 to 6, wherein the second excitation means (16) is configured to excite the diaphragm (12) in a contiguous, extended area along the diaphragm (12).
8. The loudspeaker as claimed in any of claims 1 to 6, wherein the second excitation means (16) is configured to excite the diaphragm (12) at a plurality of excitation points along the diaphragm (12).
9. The loudspeaker as claimed in any of claims 1 to 8, wherein the second excitation means is configured to excite the diaphragm in a uniform manner.
10. The loudspeaker as claimed in claims 7 or 8, wherein the contiguous, extended area or the plurality of excitation points are arranged in a central symmetric manner relative to the diaphragm (12).
11. The loudspeaker as claimed in any of claims 1 to 10, wherein that part which is connected or coupled to the diaphragm (12) is attached to or contacts the diaphragm (12) via an adapter which, via supports spaced away from another, bears on the diaphragm (12), or is attached to the diaphragm (12).
12. The loudspeaker as claimed in any of claims 1 to 11, wherein that part comprising the oscillator coil (34) is attached to or contacts the diaphragm (12) via an adapter (36) such that a vibration of the oscillator coil (34) is transferred to the diaphragm (12) along an annular excitation area.
13. The loudspeaker as claimed in any of claims 1 to 12, wherein the second excitation means (16) has several exciter units (16a - 16d) driven by identical excitation signals.
14. The loudspeaker as claimed in any of claims 1 to 13, further comprising:

    a suspension (50; 60, 62) for mounting the diaphragm (12) in an oscillatory manner, such that it enables a longitudinal translation of the diaphragm (12) from an idle position of same in the direction perpendicular to the extension of the diaphragm, and wherein the translation of the diaphragm (12) from the idle position is operative to counteract the translation.
15. The loudspeaker as claimed in any of claims 1 to 14, further comprising:

    a spider (50) by means of which the diaphragm (12) is suspended.
16. The loudspeaker as claimed in any of claims 1 to 15, wherein the diaphragm (12) is mounted, along the circumference, by axles (60) extending perpendicularly to the extension of the diaphragm, so as to be movable in the direction perpendicular to the extension of the diaphragm, a spring means (62) being provided at each axle (60) which is attached, with one end, to the circumference of the diaphragm (12), whereas the other end is fixed in a stationary manner.
17. The loudspeaker as claimed in any of claims 1 to 16, wherein the first and second excitation means (14, 16) are configured to operate in an electrodynamic manner, the first excitation means (14) having a first oscillator coil (24) and a permanent magnet (20) and being attached to the diaphragm (12), and the second excitation means (16) having a second oscillator coil (70) which surrounds the first excitation means (14) to interact with the first permanent magnet (20).
18. The loudspeaker as claimed in any of claims 1 to 17, wherein the first excitation means (14) has a cone-shaped part which is moveable towards a further, non-attached part of the first excitation means (14), and whose cone peak is attached to the diaphragm (12) and defines an excitation point where a mechanical vibration of the first excitation means (14) is transferred to the diaphragm (12).
19. The loudspeaker as claimed in any of claims 1 to 18, further comprising a backpanel (54) where the diaphragm (12) is suspended such that it is moveable, in a translatory manner, in the direction perpendicular to the extension of the diaphragm, and where the second excitation means (16) is attached, and which forms, along with the diaphragm, a bass reflex housing.

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