Planar dynamic acoustic transducer

Abstract

The invention relates to a planar dynamic sound transducer (0) having at least one magnet arrangement (1), which has a plurality of magnetic poles and at least one sound opening (13), and having a diaphragm (2), which has at least one conductor track (21), wherein the magnet arrangement (1) has an inner region (11), which comprises the magnetic pole, and an edge region (14), which surrounds the inner region (11) and connects the elements thereof to one another, and wherein the inner region (11) of the magnet arrangement (1) is arranged perpendicular to a horizontal plane (X, Y), offset from the conductor track (21) of the diaphragm (2) and in the horizontal plane (X, Y), the conductor track (21) of the diaphragm (2) is aligned with the conductor track (21) of the diaphragm (2). Y) and the conductor track (21) of the membrane (2) are arranged at least in an overlapping manner, preferably in a superimposed manner. The planar dynamic acoustic transducer (0) is characterized in that the edge region (14) of the magnet arrangement (1) further comprises at least one mechanical, acoustic and / or electrical function of the planar dynamic acoustic transducer (0).

Description

Technical Field

[0001] The invention relates to a planar dynamic sound transducer. Background Art

[0002] To generate sound, for example in loudspeakers, so-called acoustic transducers are used as sound sources, which convert an electrical voltage into an acoustic signal. Conversely, an acoustic transducer can also convert an acoustic signal as an alternating sound pressure into an electrical signal or voltage, for example in a microphone. This can be done according to different principles.

[0003] 1. Dynamic sound transducer

[0004] Nowadays, electrodynamic or dynamic loudspeakers which operate according to the electrodynamic principle are widely used. Thus, an electrical conductor is placed in a magnetic field. The magnetic field can be generated using field coils or permanent magnets. If the electrical conductor is now energized, due to the Lorentz force, a mechanical movement of the electrical conductor occurs, which depends on the direction of the current flow. The mechanical movement of the electrical conductor is usually transferred to the air as the surrounding medium by means of a diaphragm element, where sound waves are generated as the acoustic signal. The detection of the sound waves can be reversed and used, for example, in a microphone.

[0005] Dynamic acoustic transducers with a cone design are widely used, which consist of a magnet system (also called a magnet device), a voice coil, a shaped diaphragm, a suspension, and a housing or chassis, and can be called an electric cone speaker or a permanent magnet cone speaker, depending on how the magnetic field is generated. In any case, the conical design of the diaphragm and the cylindrical shape of the voice coil result in a relatively high structure in the direction of sound emission, resulting in a relatively large installation space. The components of such dynamic acoustic transducers also result in a non-negligible weight. The sound waves are generated in a small area or at a specific point, which does not correspond to natural sound waves. In addition, the strict mechanical tolerances required between the coil and the magnet system and the complex assembly of the above and other individual parts lead to considerable development and manufacturing costs.

[0006] However, acoustic transducers based on the above-mentioned established dynamic acoustic transducer principle dominate commercial products despite the disadvantages of dynamic acoustic transducers in terms of power and sound quality, which disadvantages can only be mitigated by enormous efforts.

[0007] For example, the diaphragm can be designed to be flat; however, in such a design it has a tendency to increase undesirable natural oscillations or modes and must also be mechanically damped and stiffened, which increases the moving mass, whose inertia impairs the reproduction of high acoustic frequencies. Simplifying the magnet system, for example by omitting the pole plate or by positioning the voice coil lower in the magnet system, results in a less focused, inhomogeneous magnetic field that is asymmetrical relative to the resting position of the diaphragm, which results in lower efficiency and increased nonlinear harmonic distortion. See, for example, WO 2011 / 013223 A1, methods of generating a driving force radial to the diaphragm axis and mechanically redirecting it in an axial direction result in a significantly more complex design, while greatly increasing the cost of the structural parts and their assembly.

[0008] US2015 / 256912 A1 shows an example of a dynamic loudspeaker with a flat diaphragm integrated into a larger structure. An automotive interior trim part has a hole into which a flat loudspeaker diaphragm consisting of a circumferential elastic surround and a rigid diaphragm plate is inserted. A bridge-like support is attached to the back of the trim part, spanning the diaphragm opening, and an electromagnetic actuator is attached in the middle of the bridge-like support, the voice coil of which deflects the diaphragm from its resting position to generate sound. Some progress has been made in terms of overall construction depth and complexity of the components; however, the disadvantages of the flat diaphragm design already mentioned also exist, and a large number of individual components are still required, which must be prefabricated separately and then assembled.

[0009] 2. Electrostatic acoustic transducer

[0010] Another known sound transducer principle is the electrostatic system, which consists of one or two flat electrode grids and a flat stretched membrane positioned between them. With the help of a relatively high polarization voltage modulated by the useful signal, an electrostatic force is generated between the diaphragm and the electrodes, which deflects the diaphragm and generates acoustic sound.

[0011] The goal of a flat design and a relatively simple construction has been achieved in connection with many applications. To this end, the prior art includes, for example, DE 10 2006 045 385 A1, the application of this principle to the sound reinforcement of the interior of a car. However, during operation there is a risk that the diaphragm may come into contact with one of the electrodes due to excessive deflection or external air pressure fluctuations and adhere electrostatically to this electrode until the polarization voltage is switched off.

[0012] In order to reduce this risk of interruption, other measures are required, such as additional electrical insulation, multilayer diaphragm construction or high mechanical diaphragm tension, which increase the manufacturing costs and impair the acoustic power (reduced efficiency, mass damping of high vibration frequencies, reduced low-frequency reproduction due to the high fundamental resonance frequency). There are also disadvantages due to the fact that the electric polarization voltage is usually several hundred volts. In the event of a fault, this can cause danger or damage to personnel or technical systems. In addition, parasitic electrical effects in the power supply line lead to a significant voltage drop, which depends on the line length and must be compensated by technical efforts, for example by even higher source voltages or complex line construction. Alternatively, the high-voltage source can be positioned in the immediate vicinity of the acoustic transducer, but this requires additional lines for the supply voltage and additional installation space. Each of these variants has considerable disadvantages in applications such as, for example, the interior of a motor vehicle.

[0013] 3. Surface transducer

[0014] A different approach is taken using surface transducers, bending wave transducers and similar systems. Here, a flat solid body is excited by one or more point actuators to vibrate or bend waves, which in turn results in acoustic radiation.

[0015] The disadvantage here is that considerable design and signal processing measures are required to achieve a sufficiently controlled acoustic behavior in a vibrating surface. There must be no excessive or nonlinear resonances at the frequencies corresponding to the surface's own modes, and the power of the acoustic radiation should drop as little as possible between these frequencies. Due to the relatively large oscillating masses, especially at high frequencies, these requirements are technically challenging.

[0016] As soon as existing surfaces, for example from screens, furniture or vehicle interiors or body parts, are used, a particularly efficient use of space is achieved. Examples are US 6,181,797 B1 (automobiles) and US 6,332,029 B1 (screens and other applications). However, this versatility requires compromises in function and design. The shaping, assembly, thickness and material composition as well as the positioning of the actuators can usually only be optimized to a very limited extent with respect to the acoustic power, and the required vibrations may be detrimental to the original function or the life of the flat structural parts. In addition, the structural parts show signs of long-term aging, which can significantly deteriorate their vibration characteristics, such as elastic changes (embrittlement or softening), mechanical tolerances or couplings or connections to adjacent components.

[0017] 4. Plane dynamic principle

[0018] Planar dynamic acoustic transducers have also been known for some time and are essentially composed of one or two planar magnetic devices, with a diaphragm having conductor tracks applied thereto being positioned parallel to or between the planar magnetic devices. When an electric current flows, the electrically conductive conductor tracks interact with the magnetic field of the multi-pole magnetic device and generate forces acting normal to the plane of the diaphragm, which elastically deflect the diaphragm and generate air displacements and thus sound pressure.

[0019] This means that a planar dynamic acoustic transducer can generally be constructed thinner than a dynamic acoustic transducer with a conical design, although the planar dynamic acoustic transducer is longer and wider in the plane of the diaphragm. However, the increased radiation surface of the planar dynamic acoustic transducer requires a smaller deflection and is therefore subject to less distortion. In addition, a relatively large area of ​​sound radiation is achieved, which corresponds better to the conditions in a natural sound field than a more specific sound source with point contact represented by a dynamic acoustic transducer with a conical design. Another advantage of a planar dynamic acoustic transducer is the generally significantly lower mass of the membrane and the planar conductor tracks, which can improve the dispersion behavior of impulses, transients and high-frequency components.

[0020] In other words, a planar dynamic acoustic transducer (also called positive dynamic or isokinetic transducer) has a planar diaphragm on which an electrical conductor track is located and which is parallel to and at a short distance from a magnet arrangement. The magnet arrangement generates a multipolar magnetic field in such a way that the field lines in the region of the conductor tracks extend tangentially to the diaphragm and perpendicularly to the conductor tracks. When an electric current flows in the conductor tracks, a force is generated which acts perpendicularly to the diaphragm, deflects the diaphragm and generates sound. Such an acoustic transducer can be used as an acoustic transducer in loudspeakers and headphones, and in the reverse mode, i.e. by deflecting the diaphragm via acoustic sound and thereby inducing an alternating current, it can also be used as a microphone.

[0021] Planar dynamic acoustic transducers usually consist of multiple structural parts, including magnetic rods or magnetic rings, brackets, reinforcements, adhesives, etc., which must be manufactured and assembled separately. Conventional magnet arrangements for planar dynamic acoustic transducers use, for example, simple bar magnets with a north pole on one long side and a south pole on the opposite long side. These pre-magnetized rods must be placed in a bracket in an alternating alignment and bonded to it, which involves assembly work and the use of materials. Other structural parts such as spacer rings, contact parts, etc. are usually added.

[0022] In each case, the above components are then assembled to form a planar dynamic acoustic transducer, which in turn is installed in a final product, such as a loudspeaker, headphones, microphone, etc. In addition to supports, frames, screw connections, etc., acoustically effective structural parts are used, such as fabrics, resonators, foams or so-called acoustic metamaterials.

[0023] 5. Planar dynamic principle with separated magnets

[0024] US 5,901,235 A describes a planar magnetic transducer having a diaphragm comprising an electrical conductor mounted in a frame such that spaced-apart magnets are arranged on opposite sides of a central sound-emitting surface area of ​​the diaphragm by means of a metal support grid.

[0025] US 2015 110 339 A1 describes a planar multi-diaphragm electroacoustic transducer having a plurality of diaphragms arranged in one or more diaphragm modules. Each diaphragm module comprises at least one diaphragm, each diaphragm being held taut by a frame.

[0026] US2018 / 0084346 A1 describes a planar speaker unit having a housing, a first set of magnets and a diaphragm. The housing has a receiving chamber and a bottom wall. The first set of magnets is arranged on the bottom wall and is located in the receiving chamber. The diaphragm is arranged in the receiving chamber and is located above the first set of magnets. The diaphragm includes a substrate and a planar coil. The planar coil is flatly mounted on the substrate.

[0027] US10,003,876B2 describes a planar magnetic headset consisting of a single layer of parallel elongated magnets spaced apart and resting on a magnetic holder substrate. The holding substrate can be made of a plastic or metal magnetically conductive plate, with the magnets located on the inside of the plate (towards the ear). On the inside of the magnet there is a damping substrate made of plastic that carries a first continuous disc-shaped damping diaphragm. A serpentine conductor track is attached to a diaphragm located outside the magnet that excites the magnet and moves the diaphragm to generate sound according to the current in the conductor track. Further outside the conductor track, a second continuous disc-shaped damping diaphragm is attached to an external hard plastic cover.

[0028] DE 10 2017 102 159 A1 describes a planar dynamic acoustic transducer, which generally consists of two opposing magnet devices (each magnet device has a plurality of magnet bars arranged in parallel) and a diaphragm with a flat coil therebetween. The plane of the magnet device is parallel to the plane of the diaphragm. The repulsive forces between the two magnet devices and the connecting elements used to fix the devices can cause stress, torsion, deflection, etc. Usually, the diaphragm film is either directly fixed to the magnetic holder or to a separate structural part, such as a supporting frame. Mechanical stress is transmitted to the very thin, prestressed diaphragm film and impairs its flatness and / or the uniformity of the mechanical stress. In the present planar dynamic transducer having a first planar magnet device, a fastening element, a diaphragm with a conductor track, and at least one diaphragm support frame, the diaphragm support frame is clamped between the magnet device and the fastening element. An elastic decoupling element is located between the diaphragm support frame and the first magnet device and / or between the diaphragm support frame and the fastening element.

[0029] US2014 / 0270326 A1 describes a planar magnetic transducer having a frame and a main magnet row structure of elongated magnets adjacent to and having an air gap with a first surface side of a movable portion of a thin film or thin structure diaphragm, wherein conductor traces are incorporated into the diaphragm. An additional pair of magnetic sources are attached to the frame outside the vibratable area of ​​the diaphragm and mounted above the plane of the opposite second surface side of the diaphragm to amplify the magnetic energy near the second surface side of the foil diaphragm, without any row of magnets between the additional pair of magnetic sources directly in front of the second surface side of the vibratable area of ​​the diaphragm.

[0030] As is known from the relevant material data sheets, the commonly used magnetic bars made of neodymium (Nd2Fe14B) (this also applies analogously to other designs, such as rings, etc.) require very high magnetic field strengths H of, for example, 2,400 kA / m due to their high coercive field strength, which is closely related to the desired high energy density in order to be fully magnetized or polarized to the saturation range. Such field strengths, even if they are only required in pulses, can only be generated by magnetizing devices (electromagnets in the form of solenoids or coils of other shapes), the dimensions of which significantly exceed the dimensions of the structural parts to be magnetized.

[0031] Together with the requirement that the magnetic bars must be arranged with alternating polarity, this means that the magnetic bars must be individually magnetized prior to assembly. During assembly or positioning in an assembly device or injection molding tool, the magnetic bars are thus in a magnetized state, generating considerable mechanical repulsive or attractive forces, depending on their relative position relative to each other and relative to other ferromagnetic structural parts or tools. For example, the force between two magnetic bars (each measuring 2×4×40 mm) made of a common neodymium alloy "N45" is approximately 40 N when in contact and as little as 10 N at a distance of 2 mm.

[0032] To partially take this into account, US2005 / 036646 A1 in Figures 42 to 44 shows a carrier grid with pins or webs protruding perpendicular to the surface, which hinder the lateral movement of the magnetic bars due to repulsive / attractive forces until the adhesive between the magnetic bars and the carrier grid hardens. In particular, there is a constant attractive force between planar adjacent, parallel magnetic bars, usually with alternating polarity, which must be counteracted in a suitable manner in order to maintain the desired position and spacing between the magnetic bars. However, when additional magnetic bars are added, they exert forces in different directions that lift the already positioned magnetic bars out of position or twist them (especially if they rest on non-magnetic material) unless further measures are taken to temporarily fix them in place.

[0033] Another problem is the high brittleness or fragility and very low elasticity of the magnetic bars, which is due to their powder metallurgical manufacturing method. In the event of uncontrolled collisions or otherwise increased forces, this often leads to fractures and fragmentation of the magnetic bars, resulting in material waste and danger to personnel and equipment due to flying fragments or crushing. All the characteristics of the magnetic bars mentioned so far lead to a considerable effort in their storage, removal, handling, positioning and temporary fixing until they are finally fixed in their final position, for example by clamping or bonding to a carrier element or by plastic overmolding.

[0034] Planar dynamic sound transducers according to the prior art involve additional effort and costs since the multi-part construction consists of a support system for the magnetic rods, a support system for the diaphragm membrane, electrical connections, mechanical interfaces to the housing and other structural parts, protective grids and baffles or housings.

[0035] In WO 03 / 094571 A2, Figures 15-27 to 15-29 and the associated description describe an assembly method in which a magnetic bar (15-2704, 15-2904) is positioned in a cavity of an injection mold and fixed there by a spring pin (15-2900). Although the manufacturing process is described in detail elsewhere in WO 03 / 094571 A2, there is no detailed explanation of how these potentially conflicting steps (positioning, fixing and subsequent closing of the injection mold) are carried out. The need for fixing described here again illustrates the problem of the above-mentioned magnetic attraction force.

[0036] Furthermore, the cavity walls, not described in greater detail, could be made of ferromagnetic steel; the resulting attractive forces against the walls would then support temporary fixation of the magnetic bar, but at the same time create the risk of material breakage of the magnetic bar during insertion due to too rapid an impact against the cavity wall, and also make demoulding of the assembly more difficult, wherein the magnetic bar could fall out of the plastic if it adhered more strongly (magnetically) to the cavity wall or the ejector than to the adjacent plastic parts.

[0037] In a next step, the magnetic bars of WO 03 / 094571 A2 are joined together to form an assembly by overmolding with a suitable plastic, which permanently fixes their relative position and simultaneously forms an acoustically open load-bearing grid (15-2600). The magnetic bars also have an internal groove (15-2800) which is filled with plasticized plastic to achieve a positive fit. This again shows that the material bond between the plastic and the usually smooth (e.g. nickel-plated) and untempered surface of the magnetic bars is insufficient, which is comparable to the desired low adhesion between the plastic and the cavity wall.

[0038] The additional machining steps required to produce the slots in the brittle magnetic bars are usually very costly, partly due to the slow machining speeds required and / or increased scrap rates. The fact that the machining of the magnetic bars is highly cost-relevant is also shown in the statement in WO 03 / 094571 A2, according to which the alignment of the magnetic bars shown in FIGS. 15-29 on the cavity wall is advantageous in order to be able to compensate for larger thickness tolerances, which may occur when manufacturing the magnetic bars in order to save costs.

[0039] 6. Planar dynamic principle with disk

[0040] In order to simplify the design and the required manufacturing process, it is known to use planar dynamic acoustic transducers made of grids or perforated disks made of continuous hard magnetic material. Although this leads to investment costs for the casting tool, it also simplifies assembly because there are only single, usually not yet magnetized and therefore easy to handle magnetic structure parts. The relative and absolute positioning of the magnetic poles is usually reproducibly ensured in the subsequent magnetization step.

[0041] However, in the prior art, such grids only have a magnetic function and therefore always require a separate load to provide a mechanical connection with other structural parts.

[0042] JP 2008 113365 A shows such an acoustic transducer with perforated magnetic disks (22a, 22b) held by a carrier grid (24a, 24b). Here, the acoustic transducer consists of seven structural parts as well as components for electrical and mechanical contacting.

[0043] In US 3,674,946 A, a planar dynamic acoustic transducer is described which uses a resilient, flat, preformed and multi-pole magnetized magnetic material ("Plastiform", e.g. type 1037) which is punched and cut to size by stamping and similar methods. This is a barium ferrite bonded in rubber, having a low energy product of only about 1.1 MGOe. This relatively weak magnetic material is chosen because it is very easy to process, mount and adapt to the shape of a non-flat carrier grid, e.g. by magnetic attraction between the magnetic material and the carrier grid. However, the magnetic field so provided to drive the acoustic transducer is much weaker than that of other materials available at the time of filing US 3,674,946 A, and is also much weaker than the magnetic field of today's neodymium magnets, which have an energy product of up to 52 MGOe. Due to the high elasticity of the magnetic material, the use of supporting structures and other assembly components is necessary.

[0044] In a later application by the same inventor (US 4,471,173 A), in addition to the above-mentioned elastic magnetic materials, a more magnetic material made of rare earths (such as samarium cobalt) is mentioned, as well as the production of perforated disks by unspecified forming ("molded into the shape shown") or stamping ("die cutting"). This disk is an alternative to the single magnetic strip used in other embodiments of US 4,471,173 A, which also requires separate carrier grids and other discrete structural parts.

[0045] Another variant of an acoustically open disk is described in US 10,455,343 B2. The disk 14 shown here is manufactured in one piece, has only a magnetic function, and is supplemented with a carrier grid 16, a diaphragm carrier ring 12 and other structural parts. Although the disk 14 can be made of "any ferromagnetic material", the specification of the required or preferred energy product of the material between 34 MGOe and 45 MGOe limits the choice of material to anisotropic, all-metal rare earth magnets, in particular sintered neodymium magnets (Nd2Fe14B), which are commercially available in material grades with an energy product between 30 MGOe and 52 MGOe. The low geometric complexity of the disks produced by machining of sintered neodymium material and Figure 1 A and Figure 4 The uniform surface normal magnetization shown in B also points to this anisotropic material. The alternative magnetic materials ferrite, AlNiCo, plastic bonded neodymium (usually isotropic) and sintered samarium cobalt only achieve maximum values ​​of 5 MGOe, 9 MGOe, 12 MGOe or 33 MGOe and are therefore not very suitable for the acoustic transducer according to US 10,455,343 B2.

[0046] US 3,898,598 A describes a dynamic electro-acoustic transducer having two slotted disks of permanent magnets spaced parallel to each other to produce multiple aligned magnetic fields of alternating polarity in the gap between them. The main diaphragm with a flat coil is kept flat by two auxiliary diaphragms, which sandwich the main diaphragm and are arranged in the gap parallel to the disks, where the magnetic field intersects different parts of the coil vertically. Two annular elastic retainers clamp the periphery of the main diaphragm and the auxiliary diaphragm between them to give the main diaphragm the required rigidity. Alternatively, a clamping ring can provide the necessary rigidity for the main diaphragm mounted on the annular elastic retainer.

[0047] JP 2010-268045 A relates to the problem of providing a thin acoustomechanical transducer which can be assembled more easily than before and has an improved design. To this end, a planar loudspeaker is proposed, which serves as a thin acoustomechanical transducer. It comprises a pair of covers as a housing, and four pins, etc. are provided in the housing. The pins are retained by fitting their two ends into assembly holes provided in a permanent magnetic plate, and serve as a positioning tool for positioning a vibrating diaphragm and a corresponding buffer element when assembling the planar loudspeaker, and after assembly, serve as a displacement control device for controlling the displacement direction of the vibrating diaphragm. In addition, the pins are built into the housing, which maintains the design, including the flatness of the housing.

[0048] However, the disadvantage still exists that such planar dynamic sound transducers still include additional structural parts, such as contact clips, diaphragm rings, spacer rings, threaded connections, etc., which leads to corresponding manufacturing efforts, tolerance chains and costs.

[0049] For example, DE 10 2017 122 660 A1 describes a planar dynamic acoustic transducer comprising a magnetic plate with an elongated air gap transverse to the conductor. The magnetic plate is magnetized on one side with a plurality of magnetic poles, so that the magnetic plate comprises at least one north pole and one south pole on both sides along each air gap on the side facing the diaphragm and the conductor. This generates the strongest deflection force on the diaphragm directly below the magnetic bar, where the acoustic damping is also the strongest. The width of the air gap in the magnetic plate can also be freely selected, since it does not depend on the width or spacing of the conductor tracks.

[0050] However, the usually large number of individual parts and assembly steps of planar dynamic acoustic transducers leads to a corresponding amount of manufacturing and assembly work, a variety of materials that are detrimental to repairability and recycling (including the frequent use of adhesives), and quality problems due to the tolerance chain of the individual components built on each other. This leads to considerable material and labor costs in the manufacture of transducers of this type, which is an obstacle to reasonable production in large quantities and low unit costs. Summary of the invention

[0051] An object of the invention is to provide a planar dynamic sound transducer of the above-mentioned type, the manufacture and in particular the assembly of which can be simplified. Additionally or alternatively, the acoustic and / or electrical properties should be improved. This should be as simple, cost-effective, space-saving and / or weight-saving as possible. At least, the object is to provide an alternative to the known planar dynamic sound transducers.

[0052] According to the invention, this object is achieved by a planar dynamic sound transducer, a magnet arrangement, a receiver, a microphone and a loudspeaker having the features of the independent claims. Advantageous further developments are described in the dependent claims.

[0053] The invention therefore relates to a planar dynamic sound transducer having at least one magnet arrangement with a plurality of magnetic poles and at least one acoustic aperture, and having a diaphragm with at least one conductor track, wherein the magnet arrangement has an inner region and an edge region, the inner region including the magnetic poles, the edge region surrounding the inner region and connecting its elements to one another, wherein the inner region of the magnet arrangement is arranged perpendicularly to the horizontal plane away from the conductor track of the diaphragm and is arranged in a manner that at least overlaps the conductor track of the diaphragm in the horizontal plane. A planar dynamic sound transducer of this type is known, for example, from US Pat. No. 3,674,946 A mentioned at the outset.

[0054] The planar dynamic sound transducer according to the invention is characterized in that the edge region of the magnet device also includes at least one mechanical, acoustic and / or electrical function of the planar dynamic sound transducer. The mechanical function can be understood as meaning a mechanical connection, in particular an edge region of the magnet device and a support or mounting, in particular of the diaphragm, which can be direct or indirect. The mechanical function can also be a spacing or contact or non-spacing between the edge region of the magnet device and the diaphragm perpendicular to the horizontal plane. The acoustic function can be understood as influencing acoustic sound generation or sound detection. The electrical function can be understood as meaning an electrical contact, in particular an electrical contact of the conductor tracks of the diaphragm. Other mechanical, acoustic and / or electrical functions of the planar dynamic sound transducer (which are made possible by the edge region of the magnet device) are not excluded by this.

[0055] In any case, the mechanical, acoustic and / or electrical properties of the planar dynamic sound transducer can thereby be improved or enhanced individually or in combination with one another, which can correspondingly improve the quality of the planar dynamic sound transducer and corresponding products such as earphones (in particular headphones), microphones, loudspeakers, etc. Additionally or alternatively, the manufacturing, in particular the assembly effort, can be reduced by assuming more functions from one structural part in the form of the magnet arrangement or its edge region or assuming the same functions from fewer structural parts, thereby saving additional structural parts that have to be manufactured and assembled. Additionally or alternatively, certain design options can first be realized, such as a filament conductor track that electrically contacts the diaphragm by means of the magnet arrangement, as will be described in more detail below.

[0056] In any case, the edge region of the magnet arrangement can not only be used to connect or mechanically hold together the inner region or its elements (such as its poles), as previously known, but the edge region of the magnet arrangement can according to the invention be large enough, in particular in the radial direction or in the horizontal direction, in order to allow further mechanical, acoustic and / or electrical functions and properties as described above. The edge region of the magnet arrangement can be designed in particular so that the corresponding functions are possible and in particular can be performed as efficiently as possible.

[0057] Preferably, the inner area of ​​the magnet device is arranged perpendicular to and overlaps with the horizontal plane of the conductor track of the diaphragm, which can improve the efficiency of the interaction between the magnetic poles of the magnet device and the conductor track of the diaphragm. In particular, the sound hole of the magnet device can extend overlapping with the conductor track of the diaphragm.

[0058] According to one aspect of the invention, the inner region of the magnet arrangement and the edge region of the magnet arrangement are formed in one piece by the magnet body, and at least the inner region of the magnet arrangement comprises, preferably consists of, a hard magnetic material. Hard magnetic material is a permanent magnetic material and therefore has a constant magnetic field and permanently maintains the magnetic field. Alloys made of iron, cobalt, nickel or certain ferrites or even rare earths can be used to form the hard magnetic inner region of the magnet body and thus the magnetic poles of the magnet arrangement.

[0059] In other words, according to the invention, additional magnetic elements as separate structural parts can be omitted, which were previously applied to grids or the like in order to form previously known magnet arrangements together with the grids. Instead, according to the invention, the magnet arrangement or its magnet body can be designed as a mechanically stable element (in particular with an edge region having an additional mechanical, acoustic and / or electrical function as described above) and a permanent magnetic element in order to combine these properties and thus avoid at least two structural parts at this point of the planar dynamic sound transducer. This can correspondingly simplify the installation. This can also save weight and / or installation space, in particular in a direction perpendicular to the horizontal plane.

[0060] This can be implemented in such a way that at least the inner region of the magnet arrangement has a sufficient degree of hard magnetic material to achieve the desired interaction with the conductor tracks and additionally has additional, preferably non-magnetic material to complete the magnet arrangement or its inner region and form the edge region of the magnet arrangement. If the hard magnetic material is more expensive than the additional material, this can keep the manufacturing costs of the magnet arrangement low. Alternatively, however, the magnet arrangement or its magnet body can consist completely of hard magnetic material at least in the inner region, which can simplify the manufacturing and make it more cost-effective if necessary. This can also preferably apply to the edge region.

[0061] In any case, the magnet arrangement can be formed in one piece, i.e. in one piece or in a single piece, which can be done by milling, compression molding or stamping, but can also be done by one-shot forming, such as by injection molding, by die casting, by metal powder injection molding, by 3D printing, etc. This can also make the production more cost-effective, especially if only one material is used. However, the one-piece production can also be carried out in a two-component process using at least two different materials, for example by injection molding, so that at least two different materials can be used in combination with each other, as described above. For example, the inner area can have a hard magnetic material or partially or completely consist of a hard magnetic material, while the edge area can consist of a non-magnetic material, which can save hard magnetic material and thus keep the manufacturing costs of the magnet arrangement low.

[0062] It may be particularly preferred that at least the inner region of the magnet arrangement and particularly precisely or only the inner region of the magnet arrangement is hard magnetic and preferably uses hard magnetic particles, for example neodymium-iron-boron, which are embedded in a plastic material, such as polyamide, in particular polyamide 6 or 12. Arranging or concentrating the hard magnetic particles precisely or only in the inner region of the magnet arrangement, for example by means of a two-component injection molding method, may allow such hard magnetic particles to be used precisely where a magnetic field is required, in order to keep the amount of hard magnetic material as low as possible and thus keep the costs as low as possible or minimize them. The edge regions of the magnet arrangement may then be particularly free of hard magnetic material in order to save costs for hard magnetic material there.

[0063] According to a further aspect of the invention, the edge region of the magnet arrangement is formed of a different material than the inner region of the magnet arrangement, preferably of a material with a lower specific gravity and / or of a material with a lower magnetization or no magnetization and / or of an elastic material. This allows the relevant aspects described above and below to be implemented in a specific manner.

[0064] According to a further aspect of the invention, the inner region of the magnet arrangement is formed from a first material in a first process step, and the edge region of the magnet arrangement is formed from a different second material in a second process step. This can be carried out, for example, as a two-component injection molding method (2K injection molding). The designations of the first material and the second material are not to be understood as a sequence of use.

[0065] For example, in the first partial step of the entire injection molding process, a structural grid is formed from non-magnetic or weakly magnetic material components, which corresponds to the expected mechanical loads due to its shape and material properties (such as added short glass fibers or carbon fibers) and has the desired acoustic properties (such as transparency or acoustic resistance).

[0066] Once the grid has sufficiently solidified, in a second partial step, partial elements of the injection mold are moved so that a new cavity is created in the inner region, which corresponds largely to the grid structure in the horizontal plane and is located on the side of the previously created grid facing the diaphragm. This new cavity can now be filled with a component of magnetic material so that it forms a relatively thin layer on the previously created grid and is bonded to it by plasticizing its surface.

[0067] In this way, the thickness and amount of the required magnetic material component are reduced to the minimum necessary to generate the magnetic field. For example, in the case of a one-sided multi-pole magnetization, since the strength of the magnetizing field decreases exponentially with the distance to the flat magnetizer, a material thickness of 30% of the pole spacing is sufficient for this. For a pole pitch of 5 mm (between the center lines of adjacent north and south pole strips), the thickness of the magnetic material component can therefore be 1.5 mm. Edge areas and other associated elements (such as walls for forming an acoustic channel or a loudspeaker housing) that have to meet lower mechanical requirements and are produced as part of the same integral injection molding process can be produced in a first partial step from the same non-magnetic or weakly magnetic material component as the structural grid, or they can be produced in a third partial step from a third material component that, for example, consists only of a polymer matrix without a mixture.

[0068] In a third or fourth partial step, after the individual tool elements have been moved, partial regions made of elastic material, such as circumferential sealing rings or elements for vibration decoupling, can be added, wherein an interlocking connection between the elastic material and the adjacent, already produced partial regions is achieved by suitable material selection or material pairing and suitable process parameters.

[0069] If possible, surrounding or adjacent structural parts, such as shell parts or linings, are not produced in one of the partial steps shown above, they can also consist of fiber composite materials, pressed fiber materials, foam plastics or metals, etc., which are inserted into the corresponding tool cavity and are completely or partially penetrated by the molten material introduced in another partial step, or are bonded thereto in the boundary area by surface plasticization.

[0070] The selection and order of the partial steps described may be adapted to specific design, material selection and other requirements without departing from the basic idea of ​​the invention.

[0071] Without departing from the basic idea of ​​the invention, all of the aforementioned shapes of the magnet grid according to the invention can also be produced using other manufacturing methods, in particular also using additive manufacturing methods (such as 3D printing, laser sintering, stereolithography, etc.) or using powder metallurgy methods (such as laser melting, metal powder injection molding, etc.). Other structural parts, such as the rear housing wall (which forms a hollow body and cannot therefore be produced as a whole in an injection molding process), can be produced in the same printing process. Likewise, without departing from the basic idea of ​​the invention, all conventional methods of joining technology, such as threading, snap-fitting, welding, brazing, gluing, shrink fitting, as well as overmolding and similar processes, can be used to assemble or integrate the acoustic transducer according to the invention into larger components, structures, devices, housings, vehicles, etc.

[0072] According to a further aspect of the invention, the edge region and preferably also part of the inner region of the magnet arrangement is formed from a first material in a first method step, and the inner region of the magnet arrangement, preferably the remaining inner region, is subsequently formed from a different second material in a second method step. Preferably, in the first method step, the edge region and preferably part of the inner region (in particular the web) of the magnet arrangement as an inward extension of the edge region is formed from a first material that is not very magnetic or non-magnetic and is mechanically relatively hard and / or strong, and in a further method step, a further part of the inner region of the magnet arrangement (in particular the web) is formed from a second material with hard magnetic properties. This may be an alternative option for implementation.

[0073] According to a further aspect of the invention, the edge region at least partially comprises an elastic material. Preferably, the edge region is partially formed in a third method step by a different third elastic material. Preferably, in a further preferred third method step, the edge region of the magnet arrangement is supplemented by one or more partial regions of preferably elastic material. This allows the edge region to be at least partially elastic or partially elastic. This can be done as part of a multi-stage manufacturing method, in particular an injection molding method, by using corresponding materials.

[0074] According to another aspect of the invention, the edge region of the magnet device is formed perpendicular to the horizontal plane and is higher than the inner region of the magnet device. This means that the diaphragm can be directly abutted against the edge region of the magnet device perpendicular to the horizontal plane and connected to the edge region by bonding, ultrasonic welding, clamping or other joining methods. In this way, through the edge region of the magnet device itself, a distance perpendicular to the horizontal plane can be generated between the magnetic poles in the inner region of the magnet device and the conductor traces of the diaphragm, which is necessary or common for the vibration ability of the diaphragm and therefore for the acoustic generation. Therefore, no additional structural parts are required as receiving elements or as supporting elements, which can reduce the manufacturing workload. This can be an additional element or structural part that is used as a supporting element, as a receiving element or as a bearing element, for example, by gluing to support, receive or carry a diaphragm or a diaphragm film, and its function can be additionally assumed by the raised edge region of the magnet device according to the invention. So far, this can also be an element or structural part which, as a "loose" element without connection or bonding, creates a distance perpendicular to the horizontal plane between the magnet arrangement and the diaphragm, so that its function can also be additionally assumed by the raised edge region of the magnet arrangement according to the invention.

[0075] If the diaphragm is arranged perpendicularly to the horizontal plane between the magnet arrangement and the protective grid, a spacing element can be arranged between the diaphragm and the protective grid as a separate element, component or structural part in order to achieve a corresponding distance for the vibration deflection of the diaphragm. Alternatively, however, the edge region of the protective grid can also protrude perpendicularly to the horizontal plane towards the diaphragm, as described above with respect to the edge region of the magnet arrangement, in order to achieve the required distance even without an additional spacing element as a separate element, component or structural part.

[0076] According to a further aspect of the invention, the conductor tracks of the diaphragm are electrically conductively connected to contact elements of the edge region of the magnet device at at least one conductor track end, preferably at both conductor track ends, and the magnet device, preferably the edge region of the magnet device, preferably has an external contact element, which is designed to be electrically conductively contacted, preferably soldered, from the outside of the magnet device. In this way, by means of corresponding conductive contacts of the magnet device, it is possible to make electrical contact with the usually very fragile diaphragm or its conductor tracks, which itself is usually much heavier and more stable than the diaphragm. On the one hand, this allows a relatively thin or filamentary design of the diaphragm, and on the other hand, allows electrical contact of the conductor tracks of the diaphragm, for example by means of relatively strong electrical contact elements, in particular soldering points. For this purpose, the magnet device can be used for electrical bridging between the conductor tracks of the diaphragm and the connecting elements or soldering points, which can be electrically contacted from the outside of the planar dynamic sound transducer. The conductive connection between the ends of the conductor tracks or the two ends of the conductor tracks can be realized in particular via the contact surface and, if necessary, an additional conductive adhesive at this point.

[0077] According to a further aspect of the invention, the planar dynamic sound transducer has at least one supporting element which is arranged perpendicularly to the horizontal plane between the edge region of the magnet arrangement and the diaphragm and which separates the inner region of the magnet arrangement from the diaphragm by means of the hollow inner region. Alternatively, this can be used to produce a desired or usual distance perpendicularly to the horizontal plane between the magnetic poles of the inner region of the magnet arrangement and the conductor tracks of the diaphragm, for which additional structural parts are required as supporting elements or as receiving elements, but the design of the magnet arrangement can be simplified.

[0078] According to a further aspect of the invention, the conductor tracks of the diaphragm are electrically conductively connected to the contact elements of the support element at at least one conductor track end, preferably at both conductor track ends, and the support element preferably has an external contact element, which is designed to be electrically conductively contacted, preferably soldered, from the outside of the magnet device. In this way, if the support element is arranged perpendicularly to the horizontal plane so that the necessary distance perpendicularly to the horizontal plane is achieved between the poles of the magnet device and the conductor tracks of the diaphragm, without the magnet device protruding at the edge, the above-mentioned characteristics and advantages can be achieved alternatively. This can also allow the aforementioned aspects of electrical contact to be implemented in this case as described above, wherein electrical contact can then be made from the outside of the planar dynamic sound transducer on the support element.

[0079] According to a further aspect of the invention, the acoustic aperture of the magnet device at least substantially, preferably completely follows the course of the conductor track of the diaphragm. In other words, when viewed in a direction perpendicular to the horizontal plane, the acoustic aperture of the magnet device and the conductor track of the diaphragm at least substantially, preferably completely overlap. In this way, unequal magnetic poles are arranged on both sides of each conductor track portion and parallel to it. The field lines extending between these magnetic poles are optimally aligned tangentially to the conductor track due to this arrangement and have an almost constant density over the entire length of the conductor track. As a result, the magnetic material used can be optimally utilized and a driving force that is particularly evenly distributed on the surface of the diaphragm can be achieved.

[0080] According to a further aspect of the invention, the conductor traces of the acoustic aperture and the diaphragm of the magnet device are substantially elongated and extend parallel to each other in the direction of the maximum range of the magnet device. To this end, at least the conductor traces of the acoustic aperture and the diaphragm of the magnet device can be rectangular or elliptical, with an elongated extension in the horizontal plane. The rectangular or elliptical design represents a preferred option for the overall shape of the magnet device, and therefore also represents a preferred option for the entire planar dynamic acoustic transducer, so as to achieve a preferred or maximum extension. In any case, the number of parallel conductor trace segments and connectors (sweep portions) can be kept to a minimum, which can simplify the manufacture of the magnet device. This can also reduce the number of conductor trace portions near the edge regions of the magnet device that contribute relatively little to the drive of the planar dynamic acoustic transducer, but increase the length of the conductor trace, thereby increasing its resistance, because the current and therefore the driving force can decrease with the length of the conductor trace during operation, and therefore also decrease with the increase in the resistance value of the conductor trace.

[0081] According to a further aspect of the invention, the edge region of the magnet arrangement has at least one guide tongue, preferably a pair of guide tongues, and the diaphragm, preferably also the support element and / or the spacing element and / or the protective grid, has at least one through hole, preferably a pair of through holes for the guide tongue of the magnet arrangement. This also allows the edge region of the magnet arrangement to assume an additional mechanical function and facilitates assembly with the aid of the guide tongue and improves the fit or matching of the magnet arrangement and the diaphragm and possibly also other elements or components of the planar dynamic sound transducer, because the diaphragm and possibly other elements, components or structural parts can be placed on the guide tongue and thus guided and arranged in a defined manner relative to the magnet arrangement. This can be achieved in particular by a pair of guide tongues. However, more than two guide tongues can also be used, which can correspondingly improve the guidance, although the workload is increased.

[0082] Preferably, the ends of the guide tenons can be formed by applying force and / or heat after assembling the diaphragm and / or other acoustic transducer components in order to fix the diaphragm and / or other structural parts. This can ensure permanent retention while being easy and cheap to feed through. The more guide tenons are used, the more effectively this can be done, wherein on the other hand, the number of guide tenons should be appropriately limited in order to keep the workload to a minimum. For example, using four to eight guide tenons can represent a compromise between workload and effect.

[0083] In any case, when a plurality of guide tongues are used, it is advantageous to distribute the guide tongues as evenly as possible in the circumferential direction of the planar dynamic sound transducer. This is advantageous for both guidance and support.

[0084] Alternatively, in the case where the membrane is arranged perpendicularly to the horizontal plane between the magnet arrangement and the protective grid, this can also be implemented in such a way that one or more guide tongues are arranged at the edge of the protective grid and are in particular formed integrally there, and the edge region of the magnet arrangement has one or more corresponding through holes. In this way, the same effect can be achieved with the same technical means, which only need to be arranged differently with respect to the magnet arrangement and the protective grid.

[0085] According to a further aspect of the invention, the edge region of the magnet arrangement has at least one receptacle, preferably a plurality of receptacles, for receiving fastening means, preferably screws, and the diaphragm, preferably also the support element and / or the spacing element and / or the protective grid, has at least one through hole, preferably a plurality of through holes for the fastening means. This allows a mechanically simple and durable connection. In particular, screws can be used for this purpose, which can be removed particularly easily and non-destructively in order to replace elements or repair the planar dynamic sound transducer or to separate its individual parts and feed them into a material cycle (recycling). For this purpose, such receptacles can also be formed as internal threads or be provided with threaded inserts.

[0086] According to a further aspect of the invention, the edge region of the magnet arrangement has at least one hook, preferably a plurality of hooks, for gripping around the diaphragm, preferably or the spacing element or the protective grid, wherein preferably the hook head facing away from the magnet arrangement is formed magnetically. In other words, this can be used to provide a snap, latch or clamping connection for holding and positioning an element or a structural part of the planar dynamic sound transducer, which can be implemented simply and cheaply as an alternative. In particular, this allows the holding function to be combined with the positioning function in one element or in one step, which can be particularly simple and cost-effective.

[0087] Preferably, the hook can be designed magnetically, in particular at its upper end perpendicular to the horizontal plane, in order to magnetically mount other structural parts there, such as ear pads of headphones. This can allow the realization of additional functions in a simple, cost-effective and / or space-saving manner.

[0088] According to a further aspect of the invention, the edge region has at least one, preferably horizontal, cavity, preferably a plurality of, preferably horizontal cavities, which are preferably open to at least one sound hole, particularly preferably to a plurality of sound holes, wherein the length of the cavity and / or the distance between two holes of the cavity are selected so that at least one acoustic frequency having a wavelength in a predetermined ratio to the length of the cavity and / or the distance between two holes of the cavity undergoes resonance and / or reflection.

[0089] According to a further aspect of the invention, the inner region, preferably at least one magnetic web of the inner region, more preferably a plurality of magnetic webs, most preferably all magnetic webs, have at least one, preferably horizontal, cavity, preferably a plurality of, preferably horizontal cavities, which are preferably open to at least one sound hole, more preferably to a plurality of sound holes, wherein the length of the cavity and / or the distance between the two holes of the cavity is selected so that at least one acoustic frequency having a wavelength in a predetermined ratio to the length of the cavity and / or the distance between the two holes of the cavity undergoes resonance and / or reflection.

[0090] Therefore, cavities can be introduced in the inner area and / or edge area of ​​the magnet device, preferably horizontally and / or parallel to the maximum range of the magnet device, for example by means of sliders in an injection molding tool, by mechanical post-processing, or by corresponding additive one-time forming (such as laser sintering, 3D printing, etc.). These cavities can be provided with holes at selected positions, through which sound flows can enter and exit. At certain sound frequencies where the wavelength is in a certain ratio to the cavity length or the opening distance, resonances and / or reflections may occur, which may overlap with the regular sound radiation of the planar dynamic sound transducer. Depending on the phase position of the resonance and / or reflection, this superposition can be constructive or destructive. This means that the sound emitted to the outside can be amplified or attenuated at these frequencies.

[0091] This allows an acoustically effective shaping of the magnet arrangement to be achieved. This can be done using only the edge regions of the magnet arrangement or only the inner region of the magnet arrangement. However, for this purpose, both regions of the magnet arrangement can also be used in combination with each other. In any case, the system can be designed for maximum absorption and destructive interference in order to minimize the sound emitted to the outside. Alternatively, the design can also be used to reduce unwanted reflections and standing waves from the rear housing wall, for example in headphones with a closed housing. Alternatively, for example, high frequencies emitted by the diaphragm with a reduced sound pressure due to its mass suppression can be amplified by the resonator effect, thereby producing a uniform, linear sound impression up to the high frequencies.

[0092] According to a further aspect of the invention, the inner area is partly acoustically more transparent, in particular for high sound frequencies, and in other parts acoustically more opaque, in particular for high sound frequencies. In other words, this involves the construction of the inner area and the shaping of the opening areas in a part of the inner area is provided in such a way that this is accompanied by acoustic transparency, in particular for high sound frequencies, while in the remaining areas of the grid the opening areas are shaped such that they are acoustically less transparent or opaque, in particular for high sound frequencies. This leads to a reduction in the size of the acoustic openings, which leads to a reduction in the directivity of the sound radiation, which is determined by the ratio between the size of the surface radiating outwards and the signal frequency.

[0093] According to a further aspect of the invention, the planar dynamic acoustic transducer has a pair of mirror-symmetrical magnet arrangements surrounding the diaphragm perpendicular to the horizontal plane. This allows the magnet arrangements to be arranged on both sides of the diaphragm, which can expand the design possibilities of the planar dynamic acoustic transducer. Implementing this by means of two mirror-symmetrical magnet arrangements (which are identical and matched to each other) allows the same structural parts to be used twice, thereby keeping manufacturing costs low.

[0094] In other words, the two magnet arrangements may preferably be largely identical and symmetrical along a main axis.The two magnet arrangements may preferably be mechanically reinforced by their shape and / or by embedding and / or connecting them with reinforcing elements.

[0095] According to a further aspect of the invention, the magnet arrangement has at least one further inner region which has magnetic poles and is surrounded by the edge region.

[0096] In other words, the edge region is shaped so that it has one or more additional inner regions with magnetic material and an optional receptacle for a diaphragm membrane with conductor tracks. These additional inner regions can be located near the first inner region or completely or partially surround the first inner region. By attaching the diaphragm membrane to the contacting conductor tracks, these inner regions can be operated as further independent sound transducers. They can differ from each other and / or from the first sound transducer, for example in terms of size, grid structure, diaphragm offset, and are therefore suitable, for example, for reproducing different frequency ranges. To this end, the various sound transducers can be excited with their own electrical signals containing only the relevant signal frequencies. These signals can be generated, for example, by digital signal processing and subsequent digital-to-analog conversion and amplification, or by passive structural parts (such as capacitors or passive filter networks).

[0097] The advantage is that the individual acoustic transducers can be dimensioned and optimized for the reproduction of their respective frequency ranges. For example, low signal frequencies generally require significantly larger diaphragm areas and diaphragm travels, while high signal frequencies can be emitted by a light diaphragm with a small surface area. This also prevents a strong increase in the directivity of the acoustic radiation towards high frequencies.

[0098] Particularly small embodiments of the first or additional grid area and the associated diaphragm are also suitable for use as an electrodynamic microphone.

[0099] The different acoustic transducers mentioned above can also be shaped similarly or identically and excited with different digital-to-analog conversion and amplification signals generated, for example, by digital signal processing such as beamforming or wave field synthesis, in order to obtain, for example, controllable directivity of acoustic radiation or simulation of arbitrarily shaped acoustic wave fronts. In this way, localized sound or virtual acoustic environments can be created.

[0100] According to another aspect of the invention, the magnet device has at least one further inner region which has no magnetic poles and is surrounded by an edge region. This further inner region may also be referred to as a second inner region in order to distinguish it from the inner region previously considered solely as the first inner region.

[0101] In other words, the edge region is shaped so that it has one or more additional internal regions that are free of magnetic material and have an optional receptacle for a diaphragm film. These additional internal regions may be located near the first internal region or completely or partially surround the first internal region. These internal regions may be operated as so-called passive radiators by attaching a diaphragm film. They may differ from each other and / or from the first sound transducer, for example, in terms of size, grid structure, diaphragm stroke, etc., and have a corresponding first-order resonance frequency in conjunction with the connected air volume. In order to adjust the resonance frequency and, for example, to obtain a desired low value, the pretension and mass of the diaphragm film may be changed, for example, by changing the film thickness or by mechanically constructing (wrinkling, embossing, etc.) the diaphragm film or by using an additional material with mass that is permanently bonded to the diaphragm film, for example, by gluing, lamination, overmolding, etc. Passive radiators may be strongly acoustically coupled to active sound transducers at the rear through a common volume of air separated from the surroundings, so that they are resonated by these air excitations at a specific signal frequency, which is accompanied by a phase shift. As a result, an additional sound radiation of certain frequencies is obtained, which by design is mainly superimposed on the sound radiation of the active sound transducer, thereby increasing the total sound energy emitted at these frequencies (for example in the bass range).

[0102] According to a further aspect of the invention, the edge region of the magnet arrangement has at least one additional wall, which extends substantially outside the horizontal plane and acoustically separates the inner region of the magnet arrangement from the further inner region. In particular, the additional second wall may extend substantially exactly perpendicular to the horizontal plane or extend away from the edge region, which may be considered to extend in the horizontal plane. In any case, the additional wall may provide structural and / or acoustic isolation.

[0103] According to a further aspect of the invention, an edge region of the magnet arrangement is formed as a baffle.

[0104] In other words, the edge region is shaped such that it fulfils the function of a baffle, i.e. it largely prevents an acoustic short circuit between the front and rear of the diaphragm in the relevant frequency range, thereby improving the reproduction of low audio frequencies (e.g. bass tones). To this end, the edge region can be enlarged to such an extent that a sufficiently long circuitous path is produced for the sound waves generated at the rear, so that at the desired sound reception position, at the lowest relevant signal frequency, it only minimally destructively superimposes with the sound waves generated at the front, i.e. the phase difference between the two sound waves is reduced from the original 180° to less than 140° (due to destructive interference, the maximum amplitude is reduced by about 3 dB). In the same manufacturing process, additional functional features such as recesses, holes, hooks, bolts, rods etc. can be produced, e.g. for assembly with other structural parts and structures and for spacing from other structural parts and structures.

[0105] Alternatively, the edge region may also be shaped to form the front and / or side walls of the loudspeaker housing and have features such as holes, threads, hooks, etc. for attaching one or more structural parts forming the side and / or rear walls. In this way, a fully or partially closed loudspeaker housing may be formed. This prevents or reduces acoustic shorting even if the dimensions are significantly smaller than those required for the baffles described above.

[0106] For efficient and integrated production, the edge area extending to form a baffle or loudspeaker housing part can also be integrated into other structural parts, such as flat housings, bodywork or decorative parts, such as housing parts of screens or lamps, outer surfaces of furniture or ceiling suspension devices or interior decoration of automobiles, and can be produced in whole or in part together with the structural parts in the same injection molding process.

[0107] Furthermore, the edge region may have further walls between the drive region and the outer edge of the edge region, which preferably extend substantially perpendicularly to the plane of the membrane. These further walls, possibly in combination with a separate rear wall, may form an acoustic channel of defined length, which guides the acoustic energy from the rear of the membrane to an acoustic outlet located in one of the outer housing walls. Thus, depending on the length and cross section of the channel, an acoustic bypass similar to the above-described baffle is formed, but with dimensions significantly smaller than those required for the above-described baffle.

[0108] Or a resonant system is formed, which consists of the air in the channel (moving mass) and the air outside the channel in the closed housing (acoustic spring), which leads to an increase in the sound radiation at the resonant frequency.

[0109] The shape and / or surface area of ​​the acoustic channel may be constant or variable over its length and it may be straight, curved or angled; thus, for example, forming a horn, an inverted horn or a so-called transmission line. These further walls may also divide the housing volume, possibly in combination with a separate rear wall, for example, to provide an independent air volume for each sound transducer if more than one active sound transducer is present.

[0110] According to another aspect of the invention, the edge region of the magnet device has at least one wall, which extends substantially outside the horizontal plane and at least partially surrounds at least one inner region. In other words, the portion of the edge region of the magnet device can be formed as one or more walls extending substantially outside the horizontal plane, which partially or completely surround at least one inner region. Optionally, the wall can also be designed as a rear wall of a housing connected, for example, by a film hinge.

[0111] This allows the plate or wall to be formed as a lateral boundary, preferably in one piece with the edge region, which can increase the freedom of design. This can also increase the stability of the magnet arrangement.

[0112] According to a further aspect of the invention, the magnet arrangement together with the rear wall forms a housing for the planar dynamic sound transducer. This can be used to create an encapsulated or closed space.

[0113] Preferably, the rear wall is connected to the wall of the edge region of the magnet arrangement, preferably via a film hinge, preferably in one piece, which simplifies assembly and production.

[0114] According to a further aspect of the invention, the edge region of the magnet arrangement has at least one wall extending substantially outside the horizontal plane and forming at least one acoustic channel designed to be in acoustic communication with the air volume above the inner region and with the surrounding atmosphere. In other words, the edge region of the magnet arrangement has one or more additional walls extending substantially outside the horizontal plane and forming one or more acoustic channels in acoustic communication with the air volume above the inner region or with one or more optional additional air volumes above the inner region and with the surrounding atmosphere. This can increase design options.

[0115] According to a further aspect of the invention, the edge region of the magnet arrangement has at least one surface element, which preferably extends substantially in a horizontal plane and is preferably formed in one piece. In other words, the edge region of the magnet arrangement may have one or more further surface elements, which can be used for assembly or integration into a larger component, device or vehicle. This can facilitate the assembly of the planar dynamic sound transducer.

[0116] The invention also relates to a magnet arrangement for use in a planar dynamic acoustic transducer as described above. In this way, the magnet arrangement can be provided as a structural part or as an assembly in order to implement the planar dynamic acoustic transducer according to the invention as described above and to be able to utilize its characteristics and advantages.

[0117] The invention also relates to an earphone, preferably a headphone, having at least one planar dynamic sound transducer as described above. In this way, the characteristics and advantages of the planar dynamic sound transducer according to the invention as described above can be implemented and utilized in earphones, in particular headphones.

[0118] The invention also relates to a microphone having at least one planar dynamic sound transducer as described above. In this way, the properties and advantages of the planar dynamic sound transducer according to the invention can be implemented and utilized in a microphone as described above.

[0119] The invention also relates to a loudspeaker comprising at least one planar dynamic acoustic transducer as described above. In this way, the characteristics and advantages of the planar dynamic acoustic transducer according to the invention can be implemented and utilized in a loudspeaker as described above.

[0120] The invention relates to a loudspeaker-microphone combination having at least one planar dynamic sound transducer as described above, wherein at least the inner area with the associated first diaphragm is configured as a loudspeaker and at least the further inner area with the associated further diaphragm is configured as a microphone. This can be an advantageous way of implementing or utilizing the corresponding properties and benefits.

[0121] In other words, the present invention relates to a magnet arrangement, which may also be referred to as a magnet grid or a magnet system. The magnet arrangement may be manufactured in one piece (monolithically) with suitable sound channel holes, for example by milling, injection molding, die casting, metal powder injection molding, compression molding, 3D printing, etc., and may be made of a suitable material, such as a plastic matrix (e.g. polyamide 6 or 12), which may be filled with hard magnetic particles, such as neodymium iron boron, at least or precisely in the inner region. For high efficiency of the acoustic transducer, the filling degree of hard magnetic particles in the surrounding material may be as high as possible, but may be adjusted according to the requirements of the part geometry and the manufacturing process. When anisotropic particles are used, a suitable magnetic field may be applied during the primary molding process or in a downstream step to mechanically align the magnetic particles, for example using permanent magnets or electromagnets in the injection mold.

[0122] In addition to or as an alternative to each other, aspects of the invention may in particular be as follows:

[0123] A planar dynamic acoustic transducer having a multi-pole magnetized grid made of a material including hard magnetic material, essentially consisting of one to four separate parts; and a substantially planar diaphragm film positioned substantially parallel to and in close proximity to the grid, with conductor traces located thereon, which generate substantially normal-area forces when current flows through the grid in interaction with its magnetic field, wherein the magnetic grid, in addition to providing the magnetic field required directly for acoustic generation, has additional specific properties or constructions and / or elements and / or features that are beneficial to the power, quality and / or assembly of the acoustic transducer and / or product.

[0124] Special features according to this aspect of the invention can be seen in the shaping and construction of the magnetic grid to improve the characteristics and / or power as an acoustic transducer or to increase functionality to achieve greater efficiency, better quality and lower cost. Specific features are explained below.

[0125] The magnet arrangement or magnet grid may have additional mechanical and / or magnetic features, such as assembly holes, studs, recesses, hooks, spacers, support platforms, magnetic poles outside the movable diaphragm surface, etc., which may allow positioning, alignment, spacing and / or mounting of additional parts or elements, such as diaphragm films, protective grids, acoustic damping materials, housings, ear pads, second mirror image magnet grids, etc.

[0126] As mentioned above, the planar dynamic acoustic transducer and associated products may therefore have other structural parts in addition to the magnetic grid, which may or must be positioned and fixed relative to each other. The magnet grid may have various elements or features that facilitate these purposes or replace some structural parts or auxiliary parts. Examples of this are:

[0127] a. Guide tenons: They can be made of the same base material as the magnet grid and thus form a natural unit with it, i.e. integral with each other, or they can be firmly connected to the magnet grid during production, for example by injection molding or 3D printing, roughly by placing them as inserts in a mold and injecting a moldable magnetic material around them, thus forming a solid unit with it. One or more such studs can make it possible to "screw in" or position other structural parts using corresponding holes or recesses. Conversely, such studs can also be connected to another structural part and inserted into corresponding holes in the magnet grid. Combinations are also possible, i.e., for example, the magnet grid can have guide tenons on one side and holes on the symmetrically opposite side. Now, a second similar magnet grid rotated by 180° can be connected to the first magnet grid and aligned on the two tenons to obtain a symmetrical drive system with two opposing magnet grids.

[0128] b. Hooks: They can be barbs that are slightly deformed during assembly in order to spring back to their original shape behind the engagement partner and create a positive fit that secures the structural parts and does not require any additional work steps or aids, such as adhesives, screws, rivets, etc. At the same time, the hooks can also have a guiding and alignment function, such as the guide tenons under point a. When forming the magnet grid, the hooks and similar functions can be formed from the base material and form a natural unit with the magnet grid, or separate hooks, for example made of spring steel, can be used and connected to the magnet grid during the forming process (e.g. overmolding).

[0129] c. Distance and load-bearing stage: Some structural parts, such as diaphragm membranes, can be positioned and fixed at a defined distance from the magnet grid. To this end, the magnet grid can have a circumferential step of appropriate height, which creates this distance and can also serve as a direct load for the diaphragm membrane by mounting it on the circumferential step by gluing, clamping or other methods. Similar solutions can also be used for other structural parts, such as protective grids, dust protection devices, seals, acoustic damping elements, etc.

[0130] d. Holes: If the various structural parts are to be connected to each other or to a housing etc. by means of screws, a holding frame may be used in conventional designs which holds the magnet arrangement and has holes. According to the invention, the magnet grid may contain these holes, which may be through holes for the screws or threaded holes for metric or self-tapping screws (possibly with threaded inserts or press-in nuts). This reduces or eliminates the additional work, tolerance risks and costs associated with the conventional assembly of, for example, ten magnet bars and a holding frame.

[0131] e. Additional poles: Due to the basic manufacturing method of the magnet grid, hard magnetic material can also be used outside the actual drive area (close to the conductor tracks) and can be magnetized if necessary. These additional poles can be used to attract other permanent magnets or electromagnets or ferromagnetic structural parts, thereby positioning and fixing them in the appropriate position. Examples of this are protective grids made of steel or ear pads with integrated carrying rings made of steel or integrated single magnets. These structural parts can be removed and reattached without tools or auxiliary materials, which can be particularly advantageous for the end user. These poles do not have to be located at the height of the drive area, but can also be located on raised areas, such as the top of hooks or guide tenons or on the outside of the magnet grid, to allow this function to be implemented where it is needed.

[0132] The magnet arrangement or magnet grid may have the same functionality as before, but with a reduced overall weight and / or cost by using lighter and / or cheaper materials or elements which may be permanently attached to or enclosed by the magnet grid, thereby partially replacing the hard magnetic material.

[0133] This aspect of the invention is based on the recognition that hard magnetic materials (such as NdFeB) have a relatively high density and are generally associated with relatively high raw material costs. Therefore, in areas where magnetic functionality is not required, the material can be replaced by other materials with lower cost and / or density. In the case where hard magnetic material is used as a filler in a plastic matrix, the same type of plastic can be used, in particular in the non-magnetic areas, but without the filler, so that good material bonding can be achieved between the areas. However, other plastics, foams, wood and many other materials are also conceivable. If the non-magnetic areas are in a plastic state, they can be printed or injection molded with other areas using 2K production, or they can be produced upstream and placed in the mold or on the printing plate as inserts and integrated and firmly bonded to the hard magnetic areas in a single molding process.

[0134] The magnetic device or magnetic grid may have features and / or integrated elements for electrically contacting conductor traces located on the diaphragm film, such as contact surfaces, soldering surfaces, bonding pads, soldering tabs, etc.

[0135] This aspect of the invention is based on the recognition that electrical contact between conductor tracks and leads can be challenging, since the conductor tracks and the diaphragm film can in many cases be very thin and temperature sensitive, so that soldering or bonding may not be possible. One solution according to the invention can be to press flat metal parts onto the ends of the conductor tracks, possibly in combination with a conductive adhesive. These contact parts or the open ends of the conductor tracks can, if necessary, have a correspondingly flat and / or thick design, which themselves can allow a soldered connection to the power supply lines and can be integrated into the magnet grid as an insert, for example, in order to allow a stable and easily established contact. This contact method can be very advantageous, in particular when the acoustic transducer is symmetrical as described above and consists only of two magnet grids and a diaphragm with conductor tracks. If necessary, some surfaces of the contact parts can be electrically insulated, for example by painting, to prevent electrical shunting through the magnetic material.

[0136] The magnet arrangement or magnet grid can be mechanically reinforced and / or strengthened by its shape and / or by elements which are firmly connected to or enclosed by the magnet arrangement or magnet grid in order to achieve greater robustness for demanding applications and / or to be able to permanently withstand repulsive forces in a symmetrical structure consisting of two mirror-image magnet grids arranged close to each other.

[0137] This means that the magnet arrangement or magnet grid, which has the core function of providing a magnetic field in the drive region, can be relatively thin, for example about 1 mm thick. However, in this embodiment, the stability and / or strength of the magnet arrangement and / or magnet grid may be compromised, because the hard magnetic material may be brittle and fragile, especially if considerable forces act on the magnet arrangement and / or magnet grid. Dynamic forces may be generated during use due to collisions or falls, and static forces may be generated in particular in a symmetrical structure consisting of two mutually repelling magnet grids. In order to improve the stability of the magnet arrangement or magnet grid, it can be enhanced by suitable structural reinforcements, struts, etc. Alternatively or additionally, other parts or materials may be integrated into the magnet arrangement or magnet grid, such as inserts, 2K injection molded parts, carbon fibers, steel rods, metal sheets, etc.

[0138] The magnet arrangement or magnet grid may be substantially symmetrical about at least one axis in order to allow the use of a second similar magnet grid for a symmetrical structure consisting of two mirrored magnet grids. For a symmetrical structure consisting of two opposing magnet grids, it may be advantageous if the same magnet grid can be used twice. In order to allow the 180° rotation required for this, it may be advantageous if the magnet grid itself has at least one axis of symmetry in addition to the various features described above.

[0139] The magnet arrangement or magnet grid may have acoustic properties that affect the sound field, sound pressure, sound velocity or sound flow in the vicinity of the sound transducer, or shape it in terms of frequency or amplitude, or affect the vibration behavior of a diaphragm membrane or other element in order to reduce or intentionally shape nonlinear distortion or frequency-dependent amplitude fluctuations in the generated sound signal.

[0140] The magnet arrangement or magnet grid can be designed to be completely acoustically transparent in its grid structure, i.e. the aperture and / or shape of the holes it contains. Alternatively, it can also have a defined acoustic impedance in order to achieve damping of unwanted vibration modes and nonlinear distortions of the diaphragm. Or it can have areas that generate acoustic resonances and thus amplify or attenuate certain sound frequencies. In order to be able to influence different frequency ranges, several acoustic paths with different path lengths and / or resonance frequencies can be implemented in the same magnet grid. In addition, (additional) areas of the magnet grid can be embodied in different, for example porous and therefore sound-absorbing materials, preferably as inserts or produced by 2K, in order to influence the sound flow or, for example, reduce unwanted reflections and modes. In this way, various quantities of sound pressure, velocity, flow and radiation can be shaped to achieve specific sound qualities and characteristics.

[0141] In areas adjacent to components of greater height, such as housings, the magnet arrangement or magnet grid can be made of an elastic material which provides an acoustic seal and decouples structure-borne noise and compensates for mechanical tolerances.

[0142] This aspect of the invention is based on the recognition that elastic elements, such as seals made of foam or silicone, are often inserted between the acoustic transducer and the housing. As described above, these elements can be integrated into the magnet grid as inserts or by 2K production in order to save corresponding work steps during assembly. On the one hand, the purpose can be sealing to prevent acoustic short circuits between the front and the rear of the acoustic transducer, and on the other hand, the purpose can be mechanical decoupling to reduce the transmission and audibility of structure-borne noise from the housing, cables or other parts to the acoustic transducer. Possible mechanical tolerances, i.e. mechanical dimensions and properties that vary during series production, can also be compensated by deforming the elastic material to a greater or lesser extent.

[0143] The magnet arrangement or magnet grid, i.e. the arrangement and shaping of the rods and recesses, can essentially directly or inversely map the course of the conductor tracks on the diaphragm film, in particular in the area of ​​connecting elements, sweeping portions, etc., so as to focus the permanent magnetic field as evenly as possible on all parts of the conductor tracks.

[0144] This aspect of the invention is based on the recognition that conventional implementations use magnetic bars extending parallel to the conductor tracks. The freedom of shaping of the monolithic magnet grid according to the invention also allows the sweeps or connections between parallel conductor track segments to be followed precisely, either directly or inversely, thereby also generating a constant magnetic field there and thus a uniform driving force over the entire film surface.

[0145] The conductor traces and the corresponding poles of the grid may extend in the longest extension direction of the acoustic transducer (e.g. the major semi-axis of the ellipse) in order to keep the number of parallel conductor trace segments and the number of connections (sweeps) low. Therefore, on the basis of the aforementioned aspects, it is also advantageous if the parallel conductor trace segments and the corresponding grid structure extend in the longest extension direction of the acoustic transducer in order to minimize the number and length of turns or connections. This simplifies the production of the grid and minimizes the number of conductor trace pieces that contribute little to the drive of the acoustic transducer in the edge region, but increases the conductor length and resistance, which can reduce the current and thus the driving force.

[0146] In summary, the various aspects and features of the invention mean that a relatively very small number of individual parts are required. As a result, the assembly and quality assurance effort can be very low and allow economical production at or below the cost level of conventional dynamic or moving coil acoustic transducers. Furthermore, the significantly improved sound quality of the planar dynamic acoustic transducer can be provided to a relatively wide customer base. BRIEF DESCRIPTION OF THE DRAWINGS

[0147] Several exemplary embodiments and further advantages of the present invention are shown and explained in more detail purely schematically in conjunction with the accompanying drawings. As shown below:

[0148] Figure 1 is a perspective schematic exploded view of a planar dynamic acoustic transducer according to a first embodiment, viewed from an oblique top view;

[0149] Figure 2 is a perspective schematic exploded view of a planar dynamic acoustic transducer according to a second embodiment, viewed from an oblique top view;

[0150] Figure 3 is a schematic perspective view of a magnet device of a planar dynamic acoustic transducer according to a third embodiment, viewed from an oblique top view;

[0151] Figure 4 Shown from below Figure 3 ;

[0152] Figure 5 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a fourth embodiment, viewed from an oblique top view;

[0153] Figure 6 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a fifth embodiment as viewed obliquely from below;

[0154] Figure 7 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a sixth embodiment, viewed from an oblique top view;

[0155] Figure 8 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a seventh embodiment, viewed from an oblique top view;

[0156] Fig. 9 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to an eighth embodiment, viewed from an oblique top view;

[0157] Fig.10 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a ninth embodiment, viewed from an oblique top view;

[0158] Fig.11 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a tenth embodiment, viewed from an oblique top view;

[0159] Fig.12 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to an eleventh embodiment, viewed from an oblique top view;

[0160] Fig.13 is a perspective cross-sectional view of a magnet device of a planar dynamic acoustic transducer according to a twelfth embodiment, viewed from an oblique top view; and

[0161] Fig.14 Shown from below Fig.13 ;

[0162] The above figures are all viewed in a Cartesian coordinate system. The longitudinal direction X is shown in the figure, which can also be called depth X or length X. The transverse direction Y, which can also be called width Y, extends perpendicular to the longitudinal direction X. The vertical direction Z extends perpendicular to the longitudinal direction X and the transverse direction Y, which can also be called height Z and corresponds to the direction of gravity. The longitudinal direction X and the transverse direction Y together form a level X, Y, which can also be called a horizontal plane X, Y. DETAILED DESCRIPTION

[0163] according to Figure 1 In the first embodiment example, viewed from bottom to top in the vertical direction Z or perpendicular to the horizontal plane X, Y, the planar dynamic sound transducer 0 has a magnet arrangement 1, a diaphragm 2, a spacing element 3 and a protective grid 4, which are held together in the assembled state (not shown) by fastening means 5 in the form of screws 5. The screws 5 can be removed non-destructively for repair or disassembly. The planar dynamic sound transducer 0 or its corresponding elements, components or structural parts is essentially flat or planar in the horizontal plane X, Y and extends there in an elliptically with the longitudinal direction X as the preferred extension direction.

[0164] The magnet arrangement 1, which can also be referred to as a magnet grid 1, is formed in one piece, i.e. in one piece or in one piece, as a magnet body 1. The magnet arrangement 1 has an inner region 11, which in a first embodiment example is formed as a recess 11 opposite an edge region 14. In this inner region 11, a magnetic rod 12 with magnetic poles and acoustic holes 13 are formed, which extend parallel to the magnetic rod 12 in the longitudinal direction X and surround the magnetic rod 12 at one end and are spaced apart from each other in the transverse direction Y. The magnetic rods 12 are each connected to each other at opposite ends via the edge region 14 already mentioned.

[0165] The diaphragm 2 formed as a relatively thin diaphragm film 2 (preferably less than 10 μm thick) is also formed in one piece by a diaphragm body 20 made of a flexible material. A conductor track 21 made of an electrically conductive material is applied to the diaphragm 2, which extends in superposition with the sound hole 13 of the magnet device 1. Therefore, the longitudinal portion 21a of the conductor track 21 extends parallel to the sound hole 13 in the longitudinal direction X, and the sweep portion 21b of the conductor track 21 surrounds the open end of the magnetic bar 12 in the transverse direction Y.

[0166] The spacer element 3, which can also be referred to as the first ring 3, has a spacer element body 30, which is also formed in one piece. The spacer element 3 has an elliptical inner area 31 as a material-free through-hole in the vertical direction Z or perpendicular to the horizontal plane X, Y, so that the spacer element body 30 elliptical surrounds the hollow inner area 31.

[0167] like Figure 1 As shown, the protective grid 4 encloses the planar dynamic sound transducer 0 in the vertical direction Z or perpendicular to the horizontal plane X, Y. The protective grid 4 is also formed in one piece as a protective grid body 40. In the inner area (not shown), the protective grid body 40 has a plurality of sound holes 41, each of which is circular and evenly distributed and surrounded by the protective grid body 40.

[0168] According to the invention, edge region 14 has additional mechanical, acoustic and electrical functions. This can expand the functional scope of planar dynamic sound transducer 0, improve its properties or quality and / or simplify its production, in particular its assembly.

[0169] As a mechanical function of the planar dynamic sound transducer 0, the retention of elements, components or structural parts is improved according to the invention, because the edge region 14 of the magnet device 1 has a plurality of receptacles 15 evenly distributed in the circumferential direction in the form of holes 15 with internal threads, each of which can accommodate a corresponding external thread of a screw 5. This allows simple and safe assembly. The diaphragm 2 has corresponding through holes 22 for the fastening device 5 or for the screw 5 on the edge side, the spacing element 3 has corresponding through holes 32 for the fastening device 5 or for the screw 5 on the edge side, and the protective grid 4 has corresponding through holes 42 for the fastening device 5 or for the screw 5 on the edge side, which overlap each other in the installed state so that the screw 5 can reach the receptacle 15 of the edge region 14 of the magnet device 1. This allows easy assembly with reliable retention.

[0170] In order to align the receptacle 15 of the edge region 14 of the magnet device 1 as simply, quickly and reliably as possible with the through-hole 22 for the fastening device 5 or for the screw 5 of the diaphragm 2, the through-hole 32 for the fastening device 5 or for the screw 5 of the spacing element 3 and the through-hole 42 for the fastening device 5 or for the screw 5 of the protective grid 4, the edge region 15 of the magnet device 1 also has a pair of guide tongues 16 in the form of guide pins 16, which are diametrically opposite to each other. The diaphragm 2 has a corresponding pair of through-holes 23 for the guide tongues 16 of the magnet device 1. Therefore, the spacing element 3 also has a pair of through-holes 33 for the guide tongues 16 of the magnet device 1. This applies correspondingly to the protective grid 4, which in turn has a pair of through-holes 43 for the guide tongues 16 of the magnet device 1.

[0171] These through holes 23, 33, 43 for the guide lugs 16 of the magnet arrangement 1 are also arranged correspondingly to one another, so that the diaphragm 2, the spacing element 3 and finally the protective grid 4 can be positioned and held one after another or together and aligned with one another by means of the guide lugs 16 of the magnet arrangement 1, so that the screws 5 can then be screwed in as described above. This can further simplify assembly, in particular positioning and alignment.

[0172] According to the present invention, the electrical function of the planar dynamic sound transducer 0 is to allow the conductor track 21 of the diaphragm 2 to contact the edge region 14 of the magnet device 1. To this end, the two conductor track ends 21c are formed flatly as contact points 21c of the conductor track 21 and are connected to the corresponding contact elements 17 or to the corresponding contact surfaces 17 of the conductor track 21 for the diaphragm 2 by means of a conductive adhesive in a downward pointing manner in the vertical direction Z or perpendicular to the horizontal plane X, Y, so that an electrical connection is formed between the diaphragm 2 and the magnet device 1 at these two points. Through the magnet body 10, the two contact surfaces 17 of the conductor track 21 for the diaphragm 2 of the magnet device 1 are conductively connected to the external contact element 18 of the magnet body 1, which points radially outward from the edge region 14 of the magnet device 1 in the form of an external contact pin 18.

[0173] The two external contact pins 18 of the edge region 14 of the magnet arrangement 1 are strong enough to make electrical contact from the outside of the planar dynamic acoustic transducer 0 by soldering the two external contact pins 18 of the edge region 14 of the magnet arrangement 1, so as to electrically feed the conductor track 21 of the diaphragm 2 and thus operate the planar dynamic acoustic transducer 0. As a result, direct electrical contact from the outside of the conductor track end 21c of the conductor track 21 of the diaphragm 2 can be omitted, as a result of which the conductor track 21 of the diaphragm 2 or the diaphragm 2 can be made relatively thin or filamentous and still be electrically contacted.

[0174] In any case, the magnet body 10 of the magnet device 1 can be formed in one piece, for example by means of a two-component injection molding method (2K injection molding method), so that a plastic material (such as polyamide) is present in the inner region, in which permanent magnets or hard magnetic particles (such as those made of neodymium iron boron) are embedded. Using the 2K method, this inner region 11 of the magnet body 1 is surrounded in one piece only by the same plastic material, so that the edge region 14 of the magnet body 1 is free of hard magnetic particles. This allows the magnet device 1 to achieve the desired magnetic properties in its inner region 11. At the same time, the manufacturing costs of the magnet device 1 can be kept low in terms of the material of the magnet body 10, because the hard magnetic particles in the edge region 14 of the magnet body 1 can be saved.

[0175] Figure 2 The planar dynamic acoustic transducer 1 of the second embodiment example substantially corresponds to Figure 1 A planar dynamic acoustic transducer 1 is exemplified in the first embodiment.

[0176] However, Figure 2The elements, components or structural parts of the planar dynamic sound transducer 1 of the second embodiment example are held in place because four snap hooks 19 are formed in one piece on the edge region 14 of the magnet device 1 of the magnet body 10, which can also be referred to as snap hooks 19 and extend upward in the vertical direction Z or perpendicular to the horizontal planes X, Y. The hook element (not shown) of the hook 19 protrudes radially inward, wherein the upper surface (not shown) of the hook element is formed to extend obliquely inward. The four hooks 19 are actually positioned at the four corners of the elliptical surface of the magnet device 1.

[0177] The edge region 14 of the magnet arrangement 1 is flat or flat with the inner region 11, so that the distance of the magnet arrangement 1 in the vertical direction Z or perpendicular to the horizontal plane X, Y upward to the diaphragm 2 is achieved by an additional element, component or structural part in the form of a one-piece support element 6. The support element 6 can also be called a receiving element 6, because it receives the diaphragm 2, or a second ring 6. The support element 6 also has an elliptical inner region 61 as a material-free through-hole in the vertical direction Z or perpendicular to the horizontal plane X, Y, so that the support element body 60 elliptical surrounds the hollow inner region 61.

[0178] Figure 2 The elements, components or structural parts of the planar dynamic sound transducer 1 of the second embodiment example are now assembled in such a way that the support element 6 is first pressed onto the magnet arrangement 1 from above, so that the hooks 19 are bent radially outwards in a spring-elastic manner in order to allow the support element body 60 to pass between them. This is also done successively for the diaphragm 2, the spacing element 3 and the protective grid 4, which is then gripped from above in the vertical direction Z or perpendicular to the horizontal planes X, Y by the radially inwardly protruding hook elements and thus retained. This means that assembly can be carried out without additional fastening devices 5 or screws 5, which simplifies assembly and saves material costs.

[0179] If necessary, a secure hold in the vertical direction Z or perpendicular to the horizontal plane X, Y can be achieved by forming the support element 6 and / or the spacing element 3 from an elastic material so as to exert a certain force from the inside or from the bottom on the hook element of the hook 19 in the vertical direction Z or perpendicular to the horizontal plane X, Y. This can also compensate for manufacturing tolerances of these elements, components or structural parts in the vertical direction Z or perpendicular to the horizontal plane X, Y.

[0180] Figure 2 Simple and reliable positioning of the elements, components or structural parts of the planar dynamic sound transducer 1 of the second embodiment example can be achieved by an elliptical design of the contour of the element, component or structural part, which corresponds to the arrangement of the snap hooks 19 and thus allows assembly with only two mirror-symmetrical configurations as described above. The elements, components or structural parts of the planar dynamic sound transducer 1 can be designed accordingly.

[0181] In addition, the upper end of the hook 19, which may be called a hook head 19a or a lock hook head 19a, may be designed to be permanently magnetized toward the top, so that other elements, components or structural parts of a product using or installing the planar dynamic sound transducer 1 can be magnetically detachably connected to the hook 19a. Figure 2 The second embodiment of the planar dynamic sound transducer 1 is exemplified by the embodiment of the present invention. This can simplify the assembly of the product and / or create further possibilities of use.

[0182] In any case, regarding Figure 1 The possibility of electrical contacting of the conductor tracks 21 of the diaphragm membrane 2 described in the first embodiment example of the planar dynamic acoustic transducer 1 can also be used in the second embodiment example, because the support element 6 now has a pair of contact elements 62 or contact surfaces 62 for the conductor tracks 21 of the diaphragm membrane 2 and a pair of external contact elements 63 or external contact pins 63. This means that the corresponding electrical functions can also be implemented and used in the second embodiment example described above.

[0183] As an acoustic function, the magnet device 1 or the magnet grid 1 can be designed with respect to the specific configuration and arrangement of the acoustic apertures 13 and the magnetic rods 12 or their magnetic poles so that the sound field, sound pressure, sound velocity or sound flow in the environment of the planar dynamic sound transducer 1 can be influenced and shaped based on frequency or amplitude, or the vibration behavior of the diaphragm film 2 or other elements can be influenced in order to reduce or intentionally shape nonlinear distortion or frequency-related amplitude fluctuations in the generated sound signal. To this end, the grid structure of the magnetic rods 12 of the magnet device 1 can be designed to be completely acoustically transparent with respect to the aperture and / or shape of the acoustic openings 13. Alternatively, however, the acoustic apertures 13 of the magnet device 1 can also have a defined acoustic impedance in order to achieve damping of undesirable vibration modes and nonlinear distortions of the diaphragm 2. Alternatively, the acoustic apertures 13 of the magnet device 1 can have areas that generate resonances and / or reflections, thereby amplifying or attenuating certain sound frequencies.

[0184] according to Figure 3 and Figure 4 As shown in the figure, this can be implemented in a specific way, for example, by introducing horizontal cavities 12a of the magnetic rod 12 along the inner region 11 and horizontal cavities 14a of the edge region 14 along the longitudinal direction X or parallel to the longitudinal direction X of the edge region 14 as the maximum extension of the planar dynamic acoustic transducer 1. Similarly, the horizontal cavities 12a of the magnetic rod 12 can also extend in the transverse direction Y. In any case, the sound can enter the cavity from the sound hole 13 of the magnet device into the cavities 12a, 14a in the longitudinal direction X through the horizontal cavities 12a of the magnetic rod 12, in the transverse direction Y through the horizontal cavities 12a of the magnetic rod 12, and in the longitudinal direction X through the horizontal cavities 14a of the edge region 14, or vice versa. For this purpose, these cavities 12a, 14a are provided with holes at selected positions, through which the sound flow can enter and exit.

[0185] In this way, as an acoustic function of the magnet device 1 and in particular of its edge region 14 and / or interior 11, resonances and / or reflections can occur at specific acoustic frequencies, the wavelength of which is in a specific ratio to the corresponding cavity length and / or the corresponding opening distance, which are superimposed on the regular acoustic radiation of the planar dynamic acoustic transducer 1. Depending on the phase position and spatial arrangement of the resonances, this superposition is constructive or destructive. This results in an amplification or attenuation of the sound emitted to the outside at these frequencies.

[0186] Figure 5 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to a fourth embodiment example, viewed obliquely from above. Figure 5 is a perspective view of a magnet arrangement 1, the edge region 14 of which has been formed as a baffle 10a, which largely prevents acoustic short circuits between the front and rear of the diaphragm in the relevant frequency range. Here, 11 denotes an inner region with a grid structure formed by magnetic bars 12, which are materially connected to non-magnetic bars 12b.

[0187] Figure 6 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to a fifth embodiment example, viewed obliquely from below. Figure 6 is a perspective view of a magnet arrangement 1, the edge region 14 of which has been formed as a front housing shell having a circumferential side wall 14b and holes 15 which can accommodate, for example, screws by means of which the front housing shell can be connected to the rear housing shell 7 in order to obtain a closed housing.

[0188] Figure 7 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to a sixth embodiment example, viewed obliquely from above. Figure 7 is a perspective view of a magnet arrangement 1, the edge region 14 of which has been formed as a front housing shell, which has a circumferential side wall 14b and holes 15, which can, for example, accommodate screws, which can be used to connect the front housing wall or shell to a rear housing wall or shell (not shown) in order to obtain a closed housing. A further wall 14c, in combination with the rear housing wall not shown, forms an acoustic channel of defined length, which feeds the acoustic energy from the rear of the membrane to the acoustic outlet 14e via a first hole 14d, delaying the acoustic energy due to the sound propagation time and / or generating standing waves, whereby the radiated acoustic energy of the entire system can be influenced based on the excitation frequency. Here, 14f represents a raised contact surface for the diaphragm.

[0189] Figure 8 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to a seventh embodiment example, viewed obliquely from above. Figure 8is a perspective view of a magnet arrangement 1, the edge region 14 of which has been formed as a front housing shell with circumferential side walls 14b and holes 15 which can, for example, accommodate screws which can be used to connect the front housing wall or shell to a rear housing wall or shell (not shown) in order to obtain a closed housing. Two further walls 14c, in conjunction with the rear housing wall (not shown), form an acoustic channel of defined length which encloses an acoustic mass for the resonance system between a first hole 14d and an acoustic outlet 14e.

[0190] Fig. 9 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to an eighth embodiment example, viewed obliquely from above. Fig. 9 is a perspective view of a magnet arrangement 1, the edge region 14 of which has been formed as a front housing shell with a circumferential side wall 14b and holes 15 which can, for example, accommodate screws which can be used to connect the front housing wall or shell to a rear housing wall or shell (not shown) in order to obtain a closed housing. The edge region 14 comprises an additional inner region 11a which is smaller than the first inner region 11 and an additional raised contact surface 14h for an additional diaphragm. Due to its reduced size, the additional acoustic transducer formed in this way is better suited for reproducing higher acoustic frequencies than an acoustic transducer formed by the first inner region 11 and the diaphragm support 14f and the associated first diaphragm.

[0191] Fig.10 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to a ninth embodiment example, viewed obliquely from above. Fig.10 Shows Fig. 9 The magnet device 1 in the embodiment of the present invention is combined with a rear housing wall (not shown) to form a housing with a closed air volume. The housing is divided into two separate air volumes by an additional wall 14i, which are respectively assigned to the first interior area 11 and the additional interior area 11a.

[0192] Fig.11 1 is a perspective cross-sectional view of the magnet device 1 of the planar dynamic acoustic transducer 0 according to the tenth embodiment example, viewed obliquely from above. Here, the inner region 11 is formed by several material components processed in the same manufacturing process (such as an injection molding process). In particular, the magnetic bar 12 is implemented in the Z direction to be only as strong as the strength required to provide a single-sided multi-pole magnetic field. The magnetic bar 12 is mechanically supported or carried by another rod 12b made of non-magnetic material, which is roughly overlapped in the horizontal plane and adjacent in the vertical plane.

[0193] Fig.121 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to an example of the eleventh embodiment, viewed obliquely from above. 14 denotes an edge region, which also provides a convex contact surface 14f for the diaphragm. 11 denotes an inner region having a grid structure, in which outer holes or slots 13a have a smaller width than inner holes or slots 13b, so as to concentrate the acoustic radiation on the inner holes and convert the surface sound source roughly into a line or point sound source.

[0194] Fig.13 1 is a perspective cross-sectional view of a magnet device 1 of a planar dynamic acoustic transducer 0 according to a twelfth embodiment example, viewed obliquely from above. Fig.14 Shown from below Fig.13 . Fig.13 (top side) and Fig.14 (Bottom side) shows Fig. 9 A magnet arrangement 1 having a differently shaped sound channel formed by a side wall 14b and a further wall 14c. The edge region 14 continues outside the side wall 14b and thus seamlessly transitions into a surface 14g, which is part of a larger structure and is shown here only in simplified form as a round, flat disk. However, it can be shaped in almost any way and can, for example, form the rear wall of a screen housing or a lamp, the outer surface of a piece of furniture or a ceiling suspension, or a decorative surface of a door, roof, dashboard, luggage rack, footwell or seat of a vehicle. Additional linings, for example by attaching foils, lining materials or decorative foams, are not affected, but should be embodied in an acoustically transparent manner in the area of ​​the sound outlet. This integration into a continuous larger structure requires that the sound outlet 14e must be located essentially in the plane of the inner region 11, so that the sound is emitted to the outside on the same side as the sound transducer. This also applies accordingly when a delay channel is used, such as Fig. 9 shown.

[0195] List of reference numerals (part of the specification)

[0196] X longitudinal direction; depth; length

[0197] Y horizontal direction; width

[0198] Z vertical direction; height

[0199] X, Y level, horizontal plane

[0200] 0 Planar dynamic acoustic transducer

[0201] 1 Magnetic device; Magnetic grid; Magnetic system

[0202] 10 Magnet body

[0203] 10a Baffle

[0204] 11Inner area; depression

[0205] 11a Additional internal area

[0206] 12 Magnetic Bars

[0207] 12a The (horizontal) cavity of the inner region 11 or the magnetic bar 12

[0208] 12b non-magnetic rod

[0209] 13 Sound hole of magnet device 1

[0210] 13a The smaller width of the acoustic hole of the magnet device 1

[0211] 13b The larger width of the acoustic hole of the magnet device 1

[0212] 14 Marginal Area

[0213] 14a (Horizontal) cavity in edge region 14

[0214] 14b Side wall of edge region 14

[0215] 14c Additional wall of edge region 14 (sound channel)

[0216] 14d First hole in edge region 14 (sound channel)

[0217] 14e Sound outlet (sound channel) of edge region 14

[0218] 14f Enlarged contact surface of the membrane in the edge region 14 14g Surface of the edge region 14 (part of a larger structure)

[0219] 14h Additional raised contact surface for additional membrane of edge region 14 14i Additional wall of edge region 14 (separation of air volumes)

[0220] 15 Receptacle for fastening device 5; hole with internal thread

[0221] 16 guide tenon; guide pin

[0222] 17 Contact element or contact surface for conductor track 21 of membrane 2

[0223] 18 External contact element or external contact pin

[0224] 19 Hook; snap hook

[0225] 19a Hook head; snap hook head

[0226] 2 diaphragm; diaphragm film

[0227] 20 Diaphragm body

[0228] 21 conductor traces

[0229] 21a Longitudinal portion of conductor track 21

[0230] 21b The swept portion of the conductor trace 21

[0231] 21c conductor track end; contact point of conductor track 21

[0232] 22 Through hole for fastening device 5

[0233] 23 Through hole for guide tongue 16 of magnet arrangement 1

[0234] 3 Spacer element; first ring

[0235] 30 Spacer element body

[0236] 31 Hollow interior area

[0237] 32 Through hole for fastening device 5

[0238] 33 Through hole for guide tongue 16 of magnet arrangement 1

[0239] 4 Protection grid

[0240] 40 Protect the grid body

[0241] 41 Acoustic hole of protection grid 4

[0242] 42 through hole for fastening device 5

[0243] 43 Through hole for guide tongue 16 of magnet arrangement 1

[0244] 5 Fastening material; screws

[0245] 6 Support element; receiving element; second ring

[0246] 60 Support element body

[0247] 61 Hollow interior area

[0248] 62 Contact element or contact surface for conductor track 21 of membrane 2

[0249] 63 External contact element or external contact pin

[0250] 7 Rear housing shell

Claims

1. A planar dynamic acoustic transducer (0), The planar dynamic sound transducer has at least one magnet device (1) having a plurality of magnetic poles and at least one sound hole (13), and The planar dynamic sound transducer has a diaphragm (2) having at least one conductor track (21). The magnet arrangement (1) comprises an inner region (11) which includes the magnetic poles and an edge region (14) which surrounds the inner region (11) and connects its elements to one another. wherein the inner region (11) of the magnet arrangement (1) is arranged in a manner offset from the conductor track (21) of the diaphragm (2) perpendicular to a horizontal plane (X, Y) and in a manner at least overlapping, preferably superimposing, the conductor track (21) of the diaphragm (2) in the horizontal plane (X, Y), It is characterized in that The edge region (14) of the magnet arrangement (1) also comprises at least one mechanical, acoustic and / or electrical function of the planar dynamic sound transducer (0).

2. The planar dynamic sound transducer (0) according to claim 1, wherein the inner region (11) of the magnet arrangement (1) and the edge region (14) of the magnet arrangement (1) are formed in one piece from a magnet body (10), and At least the inner region (11) of the magnet arrangement (1), preferably exactly the inner region (11) of the magnet arrangement (1), comprises a hard magnetic material, preferably consists of the hard magnetic material.

3. The planar dynamic sound transducer (0) according to claim 1 or 2, The edge region (14) of the magnet arrangement (1) is formed from a material different from the inner region (11) of the magnet arrangement (1), preferably from a material with a lower specific gravity and / or from a material with a lower magnetization or no magnetization and / or from an elastic material.

4. The planar dynamic sound transducer (0) according to any one of the preceding claims, The inner region (11) of the magnet arrangement (1) is formed from a first material in a first method step, and the edge region (14) of the magnet arrangement (1) is subsequently formed from a second, different material in a second method step.

5. The planar dynamic sound transducer (0) according to any one of claims 1 to 3, The edge region (14), preferably also part of the inner region (11), of the magnet arrangement (1) is formed from a first material in a first method step, and the inner region (11), preferably the remaining inner region, of the magnet arrangement (1) is subsequently formed from a different second material in a second method step.

6. The planar dynamic sound transducer (0) according to any one of the preceding claims, The edge region (14) at least partially comprises an elastic material and is preferably formed partially from a different third elastic material in a third method step.

7. The planar dynamic sound transducer (0) according to any one of the preceding claims, wherein the edge region (14) of the magnet device (1) perpendicular to the horizontal plane (X, Y) is higher than the inner region (11) of the magnet device (1), Preferably, the diaphragm (2) is in direct contact with the edge region (14) of the magnet device (1).

8. The planar dynamic sound transducer (0) according to claim 7, wherein the conductor track (21) of the diaphragm (2) is electrically conductively connected to a contact element (17) of the edge region (14) of the magnet arrangement (1) at at least one conductor track end (21c), preferably at both conductor track ends (21c), and The magnet arrangement (1), preferably the edge region (14) of the magnet arrangement (1), preferably each has an external contact element (18) which is designed to be electrically conductively contacted, preferably soldered, from outside the magnet arrangement (1).

9. The planar dynamic sound transducer (0) according to any one of claims 1 to 7, The planar dynamic sound transducer has at least one supporting element (6), which is arranged perpendicular to the horizontal plane (X, Y) between the edge area (14) of the magnet device (1) and the diaphragm (2), and separates the inner area (11) of the magnet device (1) from the diaphragm (2) by means of a hollow inner area (61).

10. The planar dynamic sound transducer (0) according to claim 9, wherein the conductor track (21) of the diaphragm (2) is electrically conductively connected to a contact element (62) of the support element (6) at at least one conductor track end (21c), preferably at both conductor track ends (21c), and The support elements (6) preferably each have an external contact element (63) which is designed to be contacted, preferably soldered, in an electrically conductive manner from outside the magnet arrangement (1).

11. The planar dynamic sound transducer (0) according to any one of the preceding claims, The acoustic aperture (13) of the magnet arrangement (1) at least substantially, preferably completely, follows the course of the conductor track (21) of the diaphragm (2).

12. The planar dynamic sound transducer (0) according to any one of the preceding claims, The acoustic holes (13) of the magnet arrangement (1) and the conductor tracks (21) of the diaphragm (2) extend substantially longitudinally and parallel to each other in the direction (X) of the maximum extent of the magnet arrangement (1).

13. The planar dynamic sound transducer (0) according to any one of the preceding claims, The edge region (14) of the magnet arrangement (1) has at least one guide tongue (16), preferably a pair of guide tongues (16), and the diaphragm (2), preferably also a support element (6) and / or a spacing element (3) and / or a protective grid (4), has at least one through hole (23), preferably a pair of through holes (23) for the guide tongue (16) of the magnet arrangement (1).

14. The planar dynamic sound transducer (0) according to any one of the preceding claims, wherein the edge region (14) of the magnet arrangement (1) has at least one receptacle (15), preferably a plurality of receptacles (15), for receiving a fastening device (5), preferably a screw (5), and The membrane (2), preferably also the support element (6) and / or the spacing element (3) and / or the protective grid (4), has at least one through-hole (22), preferably a plurality of through-holes (22), for the fastening device (5).

15. The planar dynamic sound transducer (0) according to any one of claims 1 to 13, wherein the edge region (14) of the magnet arrangement (1) has at least one hook (19), preferably a plurality of hooks (19), for engaging around the membrane (2), preferably either the spacing element (3) or the protective grid (4), Preferably, the hook head (19a) facing away from the magnet device (1) is formed magnetically.

16. The planar dynamic sound transducer (0) according to any one of the preceding claims, wherein the edge region (14) has at least one, preferably horizontal, cavity (14a), preferably several, preferably horizontal, cavities (14a), which are preferably open to at least one sound hole (13), particularly preferably to several sound holes (13), The length of the cavity (14a) and / or the distance between the two holes of the cavity (14a) are selected so that at least one acoustic frequency having a wavelength in a predetermined ratio to the length of the cavity (14a) and / or the distance between the two holes of the cavity (14a) undergoes resonance and / or reflection.

17. The planar dynamic sound transducer (0) according to any one of the preceding claims, wherein the inner region (11), preferably at least one magnetic web (12), more preferably several magnetic webs (12), most preferably all magnetic webs (12) of the inner region (11), have at least one, preferably horizontal, cavity (12a), preferably several, preferably horizontal, cavities (12a), which preferably open to at least one sound hole (13), more preferably to several sound holes (13), The length of the cavity (12a) and / or the distance between the two holes of the cavity (12a) are selected so that at least one acoustic frequency having a wavelength in a predetermined ratio to the length of the cavity (12a) and / or the distance between the two holes of the cavity (12a) undergoes resonance and / or reflection.

18. The planar dynamic sound transducer (0) according to any one of the preceding claims, The inner region (11) is partly more acoustically transparent, in particular for high sound frequencies, and partly more acoustically opaque, in particular for high sound frequencies.

19. The planar dynamic sound transducer (0) according to any one of the preceding claims, The planar dynamic acoustic transducer has a pair of mirror-symmetrical magnet devices (1) surrounding the diaphragm (2) perpendicular to the horizontal plane (X, Y).

20. The planar dynamic sound transducer (0) according to any one of the preceding claims, The magnet arrangement (1) has at least one further inner region (11a) which has magnetic poles and is surrounded by the edge region (14).

21. The planar dynamic sound transducer (0) according to claim 20, The edge region (14) of the magnet arrangement (1) has at least one additional wall (14f), which extends substantially outside the horizontal plane (X, Y) and acoustically separates the inner region (11) of the magnet arrangement (1) from the further inner region (11a).

22. The planar dynamic sound transducer (0) according to any one of the preceding claims, The magnet arrangement (1) has at least one further inner region (11) which is free of magnetic poles and is surrounded by the edge region (14).

23. The planar dynamic sound transducer (0) according to any one of the preceding claims, The edge region (14) of the magnet device (1) is formed as a baffle (10c).

24. The planar dynamic sound transducer (0) according to any one of the preceding claims, The edge region (14) of the magnet arrangement (1) has at least one wall (14b), which extends substantially outside the horizontal plane (X, Y) and at least partially encloses at least one inner region (11, 11a).

25. The planar dynamic sound transducer (0) according to any one of the preceding claims, The magnet device (1) together with the rear wall (7) forms the housing of the planar dynamic sound transducer (0). The rear wall (7) is preferably connected, preferably via a film hinge, to the wall (14b) of the edge region (14) of the magnet arrangement (1), preferably formed integrally therewith.

26. The planar dynamic sound transducer (0) according to any one of the preceding claims, The edge region (14) of the magnet arrangement (1) has at least one wall (14c), which extends substantially outside the horizontal plane (X, Y) and forms at least one acoustic channel, which is designed to be acoustically connected to the air volume above the inner region (11) and to the surrounding atmosphere.

27. The planar dynamic sound transducer (0) according to any one of the preceding claims, The edge region (14) of the magnet arrangement (1) has at least one surface element (14g), which preferably extends substantially in the horizontal plane (X, Y) and is preferably formed in one piece.

28. A magnet arrangement (1) for use in a planar dynamic sound transducer (0) according to any one of the preceding claims.

29. Earphones, preferably headphones, having at least one planar dynamic sound transducer (0) according to any one of claims 1 to 27.

30. A microphone having at least one planar dynamic sound transducer (0) according to any one of claims 1 to 27.

31. A loudspeaker having at least one planar dynamic sound transducer (0) according to any one of claims 1 to 27.

32. A loudspeaker-microphone combination having at least one planar dynamic sound transducer (0) according to claim 20 or 21, At least the inner region (11) with the associated first membrane (2) is configured as a loudspeaker, and at least the further inner region (11a) with the associated further membrane is configured as a microphone.

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