Abstract: A loudspeaker is made of a panel supporting bending waves and a transducer covering a substantial portion of the panel surface. At least one constraint, for example a clamp or a mass, is fixed to the panel. Each constraint reduces the mobility of a small area of the panel. Excitation of the transducer excites bending waves in the panel; the constraints discourage simple motion and encourage the production of a plurality of bending waves instead. The constraints can constrain the panel to be excited to produce a good distribution of resonant bending wave modes.

Abstract: A contact sensitive device includes a member capable of supporting bending waves, a first sensor mounted on the member for measuring bending wave vibration in the member, the sensor determining a first measured bending wave signal, a second sensor to determine a second measured bending wave signal and a processor that optimises a product of a set of corrected impulse response measurements from each sensor to determine information related to a contact.

Abstract: A contact sensitive device includes a member capable of supporting bending waves and a plurality of sensors mounted on the member for measuring bending wave vibration in the member. The sensors measure the bending wave signals and by calculating a phase angle for each measured bending wave signal and a phase difference between the phase angles of least two pairs of sensors so that at least two phase differences are calculated, the location of the contact can be determined.

Abstract: A vehicle windscreen accessory comprising a body member, an adjustable support structure for the body member whereby the position of the body member can be adjusted, the body member comprising a mirror member and a loudspeaker having a bending wave panel-form acoustic member, the mirror member and panel-form member being integral. The accessory can be in the form of, e.g., a sun visor or a rear view mirror.

Abstract: A drive module for attachment to a rigid panel and adapted to apply bending wave energy at audio frequencies to the panel whereby the panel can radiate an audio output. The drive module has a housing adapted to be secured to the panel, at least one foot on the housing and adapted to fix the housing securely to the panel, an electro-mechanical transducer in the housing, a support for the transducer in the housing, the transducer being adapted to contact the panel to apply bending wave energy thereto when energized with an electrical audio signal, and an audio signal amplifier in the housing.

Abstract: An inertial vibration transducer for exciting bending waves in a sound-radiating member has a motor coil assembly with a tubular member adapted to be rigidly mounted directly to the sound-radiating member by adhesive means. The transducer has a magnet assembly supported on a resilient suspension, and the magnet of the magnet assembly may be disposed within the tubular member of the motor coil assembly. Loudspeakers incorporating such transducers also are disclosed.

Abstract: A panel form acoustic member capable of supporting bending wave vibration has the bending wave velocity varied in the region of coincidence to provide a range of coincidence frequencies, for causing the acoustic coupling of the bending waves in the panel to occur over a broader range of angles or for making the coupling more uniform. The member may be incorporated in a loudspeaker having a panel member (1) and an exciter (3) fixed to the panel member to excite bending waves in the loudspeaker to cause an acoustic output.

Abstract: A method of making a vehicle interior trim panel having at least one integral resonant bending wave loudspeaker panel. The method involves designing the trim panel to comprise at least one panel area capable of and intended to operate as a resonant bending wave loudspeaker, making a prototype trim panel to the design, optimising at least one parameter of the prototype panel as concerns its behavior as a resonant bending wave loudspeaker by obtaining the standard deviation, as frequency is varied, of the mechanical impedance of the panel as a function of the at least one parameter, selecting a value or values of said at least one parameter that result in a minimum of said standard deviation of the mechanical impedance of the panel, and making a trim panel in which the at least one parameter to be optimized has the selected value or values.

Abstract: An electro-dynamic inertial vibration exciter (1), for exciting a member (2) having capability to sustain and propagate input vibrational energy comprising a motor coil assembly (3, 4) having a coil (3) rigidly fixed to a tubular coil former member (4), a magnet assembly (5, 6, 7) disposed concentrically with respect to the motor coil assembly, and means (11) suspending the magnet assembly for axial movement relative to the motor coil assembly, characterized by a carrier (9) supporting the motor coil assembly (3, 4) and adapted for connection to the member (2) to be excited.

Abstract: A method of making an acoustic device in the form of a loudspeaker drive unit having a resonant panel-form member adapted to provide an acoustic output when excited with bending wave energy, comprising forming a resilient suspension for the panel-form member by molding and simultaneously fixing the resilient suspension to the panel-form member.

Abstract: A mid/high frequency loudspeaker comprising a stiff lightweight resonant panel form member, a housing in which the panel form member is mounted, a suspension connected between the edges of the panel-form member and the housing and by means of which the panel edges are restrained against movement, the arrangement being such that the housing and the panel-form member together define a cavity, and an electrodynamic exciter for applying bending wave energy to the panel-form member to cause it to resonate to produce an acoustic output, the exciter comprising a magnet assembly rigidly fixed to the housing and defining an annular gap, and a voice coil and coil former assembly disposed in the annular gap and rigidly fixed to the panel-form member near to the geometric center thereof, wherein only said panel suspension centers the voice coil and coil former assembly in the annular gap.

Abstract: A keyboard (40) having a bending wave loudspeaker (46) comprising an acoustic radiator capable of supporting bending waves and a transducer (48) mounted on the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output. The keyboard comprises a housing (38) having a lid (36) supporting individual keys (14) or a touchpad. The loudspeaker (46) may be integrally formed with the base (42) of the housing of the loudspeaker, or, if a touchpad is used, may be integral with the touchpad. The acoustic radiator may be a resonant mode bending wave radiator.

Abstract: An acoustic device, e.g. a loudspeaker, comprising a resonant multi-mode acoustic radiator panel having opposed faces, a vibration exciter arranged to apply bending wave vibration to the resonant panel to produce an acoustic output, a cavity enclosing at least a portion of one panel face and arranged to contain acoustic radiation from the portion of the panel face, wherein the cavity is such as to modify the modal behaviour of the panel. Also disclosed is a method of modifying the modal behaviour of a resonant panel acoustic device, comprising bringing the resonant panel into close proximity with a boundary surface to define a resonant cavity therebetween.

Abstract: Acoustic device comprising a member relying on bending wave action with beneficial distribution of resonant modes thereof, wherein the member has its acoustically active area at least partly bounded by means having a substantially restraining nature in relation to bending wave vibration. Operation can be below coincidence, or above if desired for active acoustic device further having beneficial location of bending wave transducer means determined with reference to and taking account of such bounding means.

Abstract: A touch pad assembly for use in an electronic article. The assembly comprises a touch pad, a coupler for mechanically coupling the touch pad to casing of the electronic article and a transducer which is mounted by coupling means on the coupler or the touch pad to drive the casing as an acoustic radiator. An electronic article can incorporate the same. An electronic article comprises a body in or on which a bending wave loudspeaker is mounted. The loudspeaker comprises a bending wave acoustic radiator and an electromechanical force transducer mounted to the radiator to vibrate the radiator to produce an acoustic output. The transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range and coupling means for mounting the transducer to the radiator.

Abstract: An atomiser comprising a fluid delivery system, a nozzle which is connected to and receives fluid from the fluid delivery system, whereby fluid is vaporised on exiting the nozzle to form an aerosol stream of fluid droplets, and a vibration assembly which comprises a member capable of supporting vibration which is positioned adjacent the nozzle and an electromechanical force transducer mounted to the member to excite vibration in the member so as to input vibrational energy into the droplets. The transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range.

Abstract: A bending wave loudspeaker includes a transparent acoustic radiator capable of supporting bending wave vibration and an electromechanical force transducer mounted to the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output. The transducer has an intended operative frequency range and includes a resonant element having a frequency distribution of modes in the operative frequency range and a coupler for mounting the transducer to the acoustic radiator. The loudspeaker may be incorporated in a telephone handset or a visual display unit.

Abstract: A device comprising a vibration system having a vibration component capable of vibrating and an electromechanical force transducer mounted to the component to excite vibration in the component. The transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range and coupler for mounting the transducer to the component.

Abstract: A vehicle component for mounting in a passenger compartment of a vehicle, the component comprising a loudspeaker having an acoustic radiator capable of supporting bending wave vibration and an electromechanical force transducer mounted to the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output, characterized in that the transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range and a coupler on the resonant element for mounting the transducer to the acoustic radiator.

Abstract: A communication device comprising a microphone, a conduction interface and an electromechanical force transducer mounted to the conduction interface to drive the interface to conduct sound to a user by bone conduction, characterised in that the transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range and coupling means for mounting the transducer to the interface.