Abstract: Audio device transducers are disclosed herein. In some embodiments, the audio device transducer comprises a coil, first and second terminals each disposed adjacent a first side of the coil, and first and second conductors each electrically coupled to the coil. The first conductor extends from the first end of the coil to the first terminal, and the second end extends from a second end of the coil to the second terminal. The second conductor includes a first conductive pathway and a second conductive pathway spaced apart from the first conductive pathway such that the coil is disposed between the first conductive pathway and the second conductive pathway. In some embodiments, the first conductive pathway is symmetric to the second conductive pathway about an axis extending through the coil.

Abstract: A speaker assembly for good thermal management in loudspeakers such as planar magnetic drivers (PMDs). The assembly comprises a front panel with one or more sound openings, one or more PMDs each associated with a respective sound opening, one or more rear thermal plates each associated with a respective PMD structure plate, and a thermal spreader plate. The PMD structure plate is mounted to the front panel, the rear thermal plate is mounted to the associated PMD structure plate, and the thermal spreader plate is mounted to the one or more rear thermal plates, thereby forming a layered heatsink assembly. In a further development, the assembly has multiple PMDs and a circuit configured to modulate power handling and frequency response between the multiple PMDs.

Abstract: A magnetic sensor includes a base material, a plurality of magnets provided at predetermined spacing on the base material, and a plurality of magnetic detection parts respectively provided close to the plurality of magnets. Each of the plurality of magnetic detection parts outputs a signal in accordance with change in the magnetic field accompanying deformation of the base material.

Abstract: The present invention relates to a flat panel speaker with which a speaker can be implemented by maximizing the number of coil turns and reduce unnecessary coil lines and weight. The flat panel speaker may include a pair of magnetic bodies with a movable coil plate therebetween, the magnetic bodies being spaced apart from each other, and movable coils patterned and printed in a printed circuit board (PCB) track shape, and laminated in even numbered layers with two or more layers, wherein: the movable coils are patterned and printed on the movable coil plate of each layer as a first coil track and a second coil track; each of the first coil track and the second coil track comprises a horizontal and vertical line coil; the horizontal line coil is formed by connecting a plurality of lines in parallel; and the vertical line coil is formed in a single line.

Abstract: A method for sound wave generation includes sensing one or more characteristics of a sound wave; calculating an inverted sound wave based on the one or more characteristics; and emitting the inverted sound wave by flowing a current, selected according to the inverted sound wave, through a wire under tension that passes through a positive pole of a magnet and a negative pole of the magnet, thereby causing the wire to vibrate.

Abstract: A magnetic sensor includes a base material, a plurality of magnets provided at predetermined spacing on the base material, and a plurality of magnetic detection parts respectively provided close to the plurality of magnets. Each of the plurality of magnetic detection parts outputs a signal in accordance with change in the magnetic field accompanying deformation of the base material.

Abstract: A planar magnetic driver including a radiating surface having a trace-free central region is described. The driver has a magnet defining an acoustic opening on a central axis. A diaphragm of the planar magnetic driver is held by mounts having a mounting profile around the central axis, and the diaphragm includes a radiating surface facing the acoustic opening. An innermost conductive trace on the diaphragm extends around a central region of the radiating surface within a magnetic flux of the magnet such that no conductive traces are on the central region. A radial distance between the innermost conductive trace and the mounting profile is less than another radial distance between the innermost conductive trace and the central axis. Accordingly, an excursion range of the diaphragm along the central axis is greater than a gap distance between the conductive trace and the magnet. Other aspects are also described and claimed.

Abstract: An improved planar diaphragm driver includes: a membrane; a first coil, disposed at a first side on a first surface of the membrane; a second coil, disposed at a first side on a second surface of the membrane and electrically connected to the first coil; a third coil, disposed at a second side on the first surface of the membrane and electrically connected to the second coil; and a fourth coil, disposed at a second side on the second surface of the membrane and electrically connected to the third coil. The first and third coils are configured to have a same flowing direction of an electric current at both respective locations thereon equidistant from a central axis of the membrane, and the second and fourth coils also are configured to have a same flowing direction of the electric current at both respective locations thereon equidistant from the central axis.

Abstract: A planar magnet speaker with excellent sound reproduction in a low frequency range and capable of providing a plurality of input controls includes a first magnet member, a second magnet member, a membrane including at least one wire formed between the first magnet member and the second magnet member, and a support frame.

Abstract: An ultra-thin planar magnetic film full-frequency speaker comprises a vibration system, a magnetic system, a frame, and an acoustic foam. The vibration system and the magnetic system are received and fixed in the interior of the frame. The vibration system comprises a vibration film and a planar voice coil, the vibration film forming a contiguous inward recess structure in the middle thereof, the planar voice coil being provided with a bar-like aperture, and the planar voice coil being adhered and fixed to the vibration film The magnetic system comprises a U-shaped soft iron and a bar-shaped magnet, the bar-shaped magnet being disposed above the U-shaped soft iron and disposed beneath the bar-shaped aperture, the U-shaped soft iron being connected to the frame by means of injection molding, and the acoustic foam being adhered to a bottom face of the U-shaped soft iron.

Abstract: The present disclosure provides a vibration diaphragm. The vibration diaphragm includes a vibration part; a suspension extending from and surrounding the vibration part; and a pattern module part formed on the vibration part. The pattern module part includes a number of ring-shaped protrusions arranged in an array and gaps formed between two adjacent protrusions. By virtue of the configuration of the pattern module part, the solution described by the present embodiment increases the surface area of the vibration part, and widens the bandwidth of the vibration diaphragm, and further improves the acoustic performance of the diaphragm.

Abstract: A new audio transducer for mobile devices having a collar with side openings that provide side venting to a back volume within an enclosure. The side openings eliminate the need for a typical frame and back vents thereon, which leads to a smaller size speaker. Each of the side openings have a maximum size less than the size of an adsorber material, which prevents the adsorber material coming into contact with the magnets, coil, and membrane of the speaker. The side openings and the size thereof also permit the enclosure to be directly filled with an adsorber material. The direct filling of the adsorber leads to more even and complete distribution of the adsorber within the back volume, which, in turn, improves sound quality of the speaker.

Abstract: A multi-diaphragm planar magnetic electro-acoustic transducer is provided, having a plurality of diaphragms arranged in one or more diaphragm modules. Each diaphragm comprises a substrate and at least one electrically conductive circuit on at least one surface of the substrate. Each diaphragm module comprises at least one diaphragm, each held taut by a frame. Each diaphragm module is disposed to one side or the other of at least one planar magnetic array, the diaphragm module being parallel to and aligned with the planar magnetic array to form the multi-diaphragm planar magnetic transducer. The planar magnets many have a vertical arrangement, a sideways arrangement, a staggered arrangement, and may comprise stators and/or a low reluctance backing plate or channel piece. The planar magnet arrays can be linear or circular.

Abstract: An electrodynamic actuator (10), has a flat coil (24) formed by tracks (22, 23) on a face of a circuit board (16) and a permanent magnet (14) the magnetic field of which passes through turns of the flat coil (24).

Abstract: An electroacoustic transducer comprises a diaphragm body part and a voice coil combined to one side of the diaphragm body part, wherein the diaphragm body part comprises non-conductive base material layers and a conductive metal layer; the metal layer is interposed between any two neighboring layers of the base material layers, and is provided with first conductive terminals conductively combined with the voice coil; each of the base material layers between the metal layer and the voice coil is provided with open holes which are formed by removal of material to allow the passage of the first conductive terminals; the central part of the diaphragm body part is combined with a reinforcing layer; and the reinforcing layer is combined to one side of the diaphragm body part away from the voice coil, and covers the regions where the first conductive terminals are located.

Abstract: An acoustic generator according to an embodiment includes a film-shaped vibrating body, a flame, and an exciter. The frame is configured to fix at least both ends of the vibrating body in a second direction perpendicular to a first direction that is a thickness direction of the vibrating body. The exciter is disposed on the vibrating body, and is configured to vibrate itself to vibrate the vibrating body. The vibrating body has a value of an average coefficient of linear expansion during a temperature change from 90° C. to 40° C. set to be not less than a value of the average coefficient of linear expansion of the vibrating body during a temperature change from 40° C. to 90° C., and set to be not less than a value of an average coefficient of linear expansion of the flame during a temperature change from 90° C. to 40° C.

Abstract: A voice coil speaker in which signal lines are properly designed and deterioration of sound quality is suppressed is provided. A voice coil speaker 1 has a diaphragm supported by a frame, and a bobbin which is connected to the diaphragm and has voice coils formed thereon. The bobbin has a bobbin main portion having the voice coils wound therearound, and an extension portion which extends from the bobbin main portion and has signal lines conducted to the voice coils, the bobbin main portion and the extension portion are integrally formed of a flexible printed board, and the extension portion is placed to extend at the back side of the diaphragm.

Abstract: An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

Abstract: Embodiments of an electromechanical transducer are presented. The electromechanical transducer includes a plurality of magnets and a substrate having a patterned conductive coil of at least one turn. The plurality of magnets are arranged such that a continuous magnetic flux path passes through each of the plurality of magnets. The substrate is located within an airgap between a given magnet of the plurality of magnets and an adjacent magnet of the plurality of magnets. The continuous magnetic flux path passes through at least a portion of the patterned conductive coil due to the location of the substrate within the airgap.

Abstract: The present invention relates to a flat-panel speaker, and more particularly, to a flat-panel speaker having a multilayer PCB pattern voice coil film, which enables induced electromotive force to be increased by controlling the impedance of the multilayer voice coil film. The flat panel speaker having the multilayer PCB pattern voice coil film according to the present invention is characterized in that the voice coil comprises: a PCB (printed circuit board) pattern printed thereon and voice coil films stacked in an even number of 4 layers or more. Two layers each of said voice coil films are mutually connected in series, and the serially-connected voice coil films are connected to each other in parallel.

Abstract: A single-ended planar transducer device for generating a sound signal based on an electrical signal comprising at least two primary rows of primary magnets, at least one return row of at least one return structure, a diaphragm, a conductive trace formed on the diaphragm, and a frame. The frame supports two primary rows to define at least one core set comprising no more than two primary rows. A primary magnetic field is established between the primary rows in the at least one core set. The frame supports at least one return row adjacent to the at least one core set. A return magnetic field is established between each return row and any primary row adjacent thereto. A first portion of the trace is arranged at least partly within each primary magnetic field and a second portion of the trace is arranged at least partly within each return magnetic field.

Abstract: A coil includes a first section, a second section spaced from the first section, a third section and a forth section connecting ends of the first and second sections for forming a closed loop. The third section includes a first portion directly contacting to the first section, and a second portion extending from the first portion and directly connecting to the second section, the first portion forms a protrusion away from the fourth section.

Abstract: To provide a speaker unit and a portable information terminal that are reduced in size and thickness and still produce a high sound pressure. A speaker unit includes: a yoke having a rectangular outline as seen in a plan view; a magnet member placed on the yoke and magnetized so that an upper surface of the magnet member has an N pole and an S pole aligned in one direction; a coil placed above and spaced from the upper surface of the magnet member; a diaphragm attached to the coil; and a frame supporting the diaphragm. An engagement protrusion which allows the frame and the yoke to engage with each other is provided on a side which is one of the sides defining the rectangular outline of the yoke and extends along the one direction.

Abstract: A voice coil using a surface mount technology (SMT) to connect the voice coil and an electrode to each other, and a SMT speaker using the voice coil. A voice coil assembly includes a voice coil formed by stacking a plurality of laminated metal plates; and a flexible printed circuit board (FPCB) for impedance matching between the voice coil and an electrode terminal for connecting an external device and for connecting the voice coil to the electrode terminal. The laminated metal plates of the voice coil are connected in series or in parallel to each other. An active device is installed on the FPCB so as to amplify a signal input through the electrode terminal and to apply the signal to the voice coil. Since the voice coil is formed by stacking the laminated metal plates and is connected to the electrode terminal through the FPCB, a SMT is used to manufacture the SMT speaker, thereby improving productivity and reliability.

Abstract: A speaker unit and a portable information terminal that are reduced in size and thickness and still produce a high sound pressure. A speaker unit includes: a yoke having a rectangular outline as seen in a plan view; a magnet member placed on the yoke and magnetized so that an upper surface of the magnet member has an N pole and an S pole aligned in one direction; a coil placed above and spaced from the upper surface of the magnet member; a diaphragm attached to the coil; and a frame supporting the diaphragm. The yoke includes an attachment which protrudes upward from an outer periphery of the yoke for attachment to the frame. The attachment has a recess at least in a central portion of the attachment which crosses the one direction.

Abstract: Contemplated planar magnetic transducers include a magnet and diaphragm arrangement such that substantially homogenous vertical and high horizontal magnetic flux density is realized in the inter-magnet space. Most preferably, the diaphragm is a tensioned polymer membrane in which the voice coil covers a significant portion of the active portion of the membrane, and the magnets are rare-earth metal-type magnets of ultra-high strength. Particularly preferred planar magnetic transducers allow for exceptionally large excursion of the diaphragm in a substantially homogenous magnetic field at virtually no distortion, thereby providing heretofore unachieved sound pressure levels. Arrays of such and other transducers are disclosed that provide a full-range speaker with acoustic plane source characteristics.

Abstract: A loudspeaker comprising a housing provided with a magnet unit that generates a magnetic field, and a membrane which is mounted in a frame and which is provided with an electrical conductor arranged in a pattern on the membrane, which membrane is positioned in the magnetic field in such a manner that a force is exerted when current is fed through the conductor pattern on the membrane, which force is capable of setting at least part of the membrane in motion so as to produce sound, wherein a part of the conductor pattern extends beyond the plane of the aforesaid movable part of the membrane near at least one end of the membrane. Preferably, the aforesaid part of the conductor pattern makes an angle of about 90 degrees with the aforesaid movable part of the membrane.

Abstract: A diaphragm for a planar speaker and a planar speaker having a long-term stability and a high reliability and exhibiting a flat sound pressure frequency property. The diaphragm for a planar speaker includes a voice coil formed by winding a wire conductor, two adhesive layers sandwiching the voice coil therebetween, and bases bonded to the two adhesive layers on the side opposite to the voice coil. The planar speaker employs the diaphragm.

Abstract: A loudspeaker comprises a diaphragm, an edge operable to support, on a frame, the diaphragm in such a manner that enables vibration thereof, and a voice coil operable to generate a driving force. The voice coil is of an approximate rectangular shape, and a length of a long axis direction of the voice coil is no less than 60% of a length of a long axis direction of the diaphragm. Positions of long sides of the voice coil to be fixed on the diaphragm are positions corresponding to nodes of a primary resonance mode in a short axis direction of the diaphragm, or in the respective vicinities thereof. Accordingly, it is possible to realize a high sound quality loudspeaker having a narrow width (elongated structure), but not easily causing resonance, thereby obtaining a flat frequency characteristic.

Abstract: A diaphragm of a speaker device, formed into an elongated configuration, has a recessed shape and includes a voice coil arrangement part extending in its longitude direction. The voice coil arrangement part has a gap with a constant width in its lateral direction and includes a voice coil supporting part for supporting a voice coil and an expanded part provided at a position along it.

Abstract: A loudspeaker comprising a magnet unit that generates a magnetic field, and a membrane which is mounted in a frame and which is provided with an electrical conductor arranged in a pattern on the membrane, which membrane is positioned in the magnetic field in such a manner that a force is exerted when current is fed through the conductor pattern on the membrane, which force is capable of setting the membrane in motion so as to produce sound, the frame being provided with metallic cooling members that partially cover the conductor pattern, wherein said cooling members are mounted in a metal housing, making contact with said housing over the larger part of their surface area, or are integral with such a metal housing.

Abstract: An electro-acoustic transducer includes a generally V-shaped diaphragm comprising a folded sheet of film material. The diaphragm also comprises two upper ends, a lower end, an inner surface, and an outer surface. A frame supports the diaphragm in at least the two upper ends of the diaphragm and a structured conductive layer is arranged on a surface of the diaphragm. Permanent magnets are attached to the frame adjacent to the upper two ends and the lower end of the diaphragm.

Abstract: An electro-acoustic transducer has a membrane comprises a folded or curved sheet of film material. A frame supports the membrane in at least an upper end thereof. A resilient suspension connects the upper ends of the membrane to the frame. A driver system is attached to the frame and the membrane for moving the membrane dependent on an electrical input signal. At least one ferromagnetic element is arranged in the membrane or on one of the surfaces of the membrane at its lower end. At least one magnet provides a magnetic field, the magnet being attached to the frame in a position adjacent the lower end of the membrane. The ferromagnetic element is pulled down by a magnetic force between the element and the magnet establishing a gap therebetween such that tensioning of the membrane is achieved by the magnetic force.

Abstract: A planar diaphragm acoustic loudspeaker having a planar diaphragm biased with a high magnetic flux density magnetic circuit which feeds an acoustic waveguide. The apparatus provides high fidelity and efficient acoustic reproduction of high frequency alternating current signals with a minimum of diaphragm resonance and with a substantially flat electrical input impedance versus frequency. The diaphragm has a substantially uniform drive across an acoustically active portion and is held in three dimensional space whereby any mass or diaphragm resonances are controlled and minimized. The acoustic waveguide mates with said diaphragm and ensures a uniform acoustic phase field and an optimal diaphragm acoustic impedance match with atmosphere.

Abstract: A push-pull magnetic-planar acoustic transducer provides easy field replacement of a diaphragm. Push-pull magnetic-planar acoustic transducers are known for the relative vulnerability of their diaphragms to damage. Replacement of the transducers in the field as been problematic because of the high repulsive force between the front and back panels and the need to obtain even tension across the diaphragm. The push-pull transducer assembly incorporates an edge hinge on which the panels can be pivoted to bring the panels into facing positions and a plurality of set screws to be fitted around the perimeter of the panels allowing essentially flat closure of the panels on one another to a working spacing engaging the diaphragm.

Abstract: A curve fitted planar loudspeaker minimizes variation and dead zones in the sound field propagated by an array of the loudspeakers. The curve fitted loudspeaker provides a plurality of sound generating transducers. The diaphragm is curved and each adjacent section fits as a section into a larger curve, eliminating or minimizing breaks in the propagated sound filed at the target distance to the target.

Abstract: A loudspeaker having a diaphragm with a fixed edge and a free edge, and a multiplicity of conductors running parallel to its length and adjacent to the free edge.

Abstract: A speaker device installed in an earpiece, for improving an antenna property in a wireless portable terminal is provided. The speaker device includes a housing, a magnet is installed on the housing, a diaphragm located a predetermined distance away over the magnet and includes a coil situated at a position corresponding to the magnet, and a cover covers the diaphragm and is in engagement with the housing, thereby forming a module. At least one inductor is provided at a feeding portion of the coil formed or installed on the diaphragm, thereby preventing the speaker device from resonating at a radio frequency (RF).

Abstract: The present invention relates to a plate type speaker with a planar diaphragm. The plate type speaker of the present invention comprises a base frame; at least one magnetic body coupled to the base frame such that opposite polarities are provided at adjacent lateral positions and are spaced apart by a predetermined distance from each other; a diaphragm; at least one coil plate that is formed with a voice coil wound on either or both of sides thereof, and is inserted vertically into spaces between the opposite polarities of the magnetic body and connected to the diaphragm; and a coil plate guide means coupled to the coil plate for guiding the position and vibration direction of the coil plate such that the coil plate is spaced from the magnetic bodies and vibrates vertically.

Abstract: An audio speaker driver having a voice coil with graduated windings such that different sections of the voice coil have different electrical resistances and/or lengths per unit of height of the voice coil. A center portion of the voice coil gives a greater BL, while outer portions give lower overall electrical resistance, such that the audio speaker driver is highly efficient and linear during low excursion operation, with a smoother transition from the linear region to the grossly non-linear region. The wire of the graduated voice coil can have varying cross-sectional area over its length, can be wound on varying on-center spacing, can be wound in different numbers of layers in the various sections, and/or it can fork into interlaced, parallel windings.

Abstract: The present invention provides a loudspeaker diaphragm and an electrodynamic loudspeaker of an elongated shape being shorter in the minor-axis direction than in the major-axis direction, which have a desirable sound reproducing capability with a high efficiency and are not significantly influenced by divided vibrations of an elongated loudspeaker diaphragm, and which are suitably installed in devices such as display devices.

Abstract: A lead wire of a voice coil is wired along the surface of a diaphragm. The lead wire is bent toward a reverse side of the diaphragm at a peripheral edge portion of the diaphragm. The lead wire is led to the interior of a frame. An external terminal is provided to extend from outside to inside the frame. In addition, a connecting portion for connecting the lead wire and the external terminal is provided inside the frame. The connecting portion is prevented from coming into contact with another part and becoming short-circuited.

Abstract: The present invention provides a planer acoustic transducer including a vibrating diaphragm including a spiral voice coil provided on both surfaces or on one surface of an insulating base film; and a permanent magnet corresponding to the voice coil, wherein, in the vibrating diaphragm, the spiral voice coil is formed by applying a wire conductor, in a coil pattern, onto a sheet-like substrate having an adhesive layer on at least one surface thereof. Alternatively, at least a portion of the vibrating diaphragm, which portion corresponds to the loop of a first or second vibration mode, is reinforced with a rigidity-imparting member; the substrate of the vibrating diaphragm is formed of a resin foam; or the voice coil is formed three-dimensionally.

Abstract: Electro-dynamic loudspeakers typically include a diaphragm having a conductor applied to one of its surfaces. The diaphragm is secured to a frame. The conductor is connected to a power supply for providing electrical current through linear traces of the conductor that interact with magnetic fields generated by magnets that are mounted to the frame. The diaphragm is driven by a motive force created when current passes through the conductor within the magnetic field. The electrical current is varied to create an acoustical output from the electro-dynamic loudspeaker. Different methods of tensioning the diaphragm are provided for simplifying the manufacturing process and for assuring proper diaphragm tension.

Abstract: Electro-dynamic loudspeakers typically include a diaphragm that is secured to a frame and has a conductor applied to at least one surface of the diaphragm. The conductor is connected to a power amplifier for providing electric current through the linear traces of the conductor that interact with magnetic fields generated by magnets that are mounted to the frame. The interaction between the current passing through the conductor and the magnetic fields cause vibration in the diaphragm that creates the sound that is heard from the electro-dynamic loudspeaker. Different methodologies of forming the conductor are provided for simplifying the manufacturing process and for locating the conductor closer to the magnetic field generated by the magnets.

Abstract: In an electroacoustic transducer of the present invention, a casing supports a diaphragm, a drive coil is provided on the diaphragm, a first magnetic structure has a first space in a center thereof provided within the casing such that a center axis penetrates the first space, and a second magnetic structure has a second space in a center thereof provided within the casing on a side opposed to the first magnetic structure with respect to the diaphragm, such that the center axis penetrates the second space. The first magnetic structure is oriented such that a magnetization direction thereof is parallel to the center axis. The second magnetic structure is oriented such that a magnetization direction thereof is opposite to the magnetization direction of the first magnetic structure.

Abstract: An electro-dynamic loudspeaker includes a frame, a plurality of magnets and a diaphragm. The frame includes a molded plastic body. The magnets may be molded into the frame in a determined configuration. The frame is mechanically coupled to the diaphragm such that the magnets are a determined distance from the diaphragm. The diaphragm may include a conductor applied to a surface of the diaphragm. The diaphragm may be driven by a motive force created when current passes through the conductor within a magnetic field formed by the magnets. The electrical current may be varied to create an acoustical output from the electro-dynamic loudspeaker.

Abstract: An electro-dynamic loudspeaker is provided with dampening arrangements that contribute to improved acoustical properties for the electro-dynamic planar loudspeaker. The dampening arrangements include providing a frame having a curved sidewall surface for reducing standing waves. Another design provides for a ferrofluid being disposed between the diaphragm and magnets of the electro-dynamic loudspeaker in order to dampen the resonance frequency of the device. In addition, a diaphragm of an electro-dynamic loudspeaker is provided with a short turn of conductor disposed along a fringe zone at an edge of the diaphragm in order to electro-dynamically dampen the edge resonance of the film.

Abstract: A new type of diaphragm transducer comprising magnets to provide magnetic field strength in a planar region and a planar diaphragm located in the said planar region. The diaphragm has a plurality of conductors on its planar surface for inducing electromagnetic forces acting on theses conductors in said planar region when current flows through said conductors. The magnets are arranged in magnetic interaction with a magnetically conducting material, preferably soft iron, to conduct magnetic field from said magnets to said planar region.

Abstract: A speaker 300 is formed using a plate such as a mobile phone display window 310 as a vibrating element. At least two dynamic actuators 950 are positioned behind the edges of the window 310 to actuate the window 310 through its boundary region so as to leave a large uniform area behind the vibrating element for containing any components, e.g. a display or battery.