The invention relates to an electromagnetic actuator, which can be connected to a backside of a plate like structure and which comprises a voice coil, a magnet system and a spring arrangement connecting the voice coil and a movable part of the magnet system. The spring arrangement comprises at least two spiral springs each having at least three spring legs. The spring legs run in radial and tangential direction in a clockwise or counterclockwise winding direction and are rotational symmetric around the coil axis. The winding directions of the spiral springs are chosen in a way that rotations around the coil axis caused by a relative movement between the voice coil and the movable part of the magnet system in the excursion direction are oriented in opposite directions. The invention also relates to an output device with a plate like structure and an electromagnetic actuator connected thereto.

A display apparatus according to an embodiment of the present disclosure includes: a display cell that displays an image and has a thin-plate shape; one or more vibration exciters that are disposed on rear-surface side of the display cell and cause the display cell to vibrate; and an opposing plate opposed to the display cell with an air gap in between. The display apparatus further includes a sound-spreading adjustment member that is disposed between the display cell and the two or more vibration exciters, and controls spreading of a sound generated by vibration caused by the two or more vibration exciters.

The present disclosure relates to a display apparatus, especially having a display panel generating sounds. A display apparatus according to the present disclosure includes: a display module; a back cover at a rear surface of the display module; a depression recessed into the back cover from a first surface of the back cover with a first width and a first depth; a penetration through from a second surface of the back cover to the depression with a second width smaller than the first width and a second depth corresponding to a difference between a thickness of the back cover and the first depth; and a first piezo vibration unit disposed at a stepped portion between the penetration and the depression.

The present invention is intended to provide a sound generating actuator which can facilitate heat dissipation from a voice coil. According to the present invention, there is provided a sound generating actuator, including: a frame; a stationary part mounted on the frame and provided with a yoke, a magnet and a top plate to compose a magnetic circuit; a voice coil configured to receive an electrical signal and vibrate due to a magnetic field and mutual electromagnetic force of the stationary part; a spring configured to dampen vibration of the voice coil and that is made of a metallic material and secured to the frame; and a contact pad that is attached to the spring and configured to transfer vibration of the voice coil.

A piezoelectric element comprising a compound represented by Formula 1, a piezoelectric device including the piezoelectric element, a vibration module including the piezoelectric device, and a display apparatus including the piezoelectric device are provided, where

(1-x)(Li.sub.zNa.sub.0.5-zK.sub.0.5)(Nb.sub.1-ySb.sub.y)O.sub.3.xCaZrO.sub.3[Formula 1] where x, y, and z have a range of 0.001x0.2, a range of 0y0.5, and a range of 0z0.2, respectively.

A speaker device according to an embodiment includes a panel, a plurality of vibration elements, and a driving unit. The plurality of vibration elements vibrate the panel. The driving unit applies, to a first vibration element, a first driving signal that includes a modulated wave provided in such a manner that a carrier wave in an ultrasonic wave band is modulated by a sound signal in an audible wave band and applies, to a second vibration element, a second driving signal that includes the carrier wave and is different from the first driving signal, so that a vibrational region is formed on the panel.

The present invention provides a display device and a television device with which it is possible to reduce the thickness of the device profile while also realizing desirable acoustic characteristics. This display device includes: a first plate-shaped object; a display module including a display element and a second plate-shaped object that supports the display element, the display module being disposed so as to face the first plate-shaped object; a liquid layer formed by sealing up a liquid between the first plate-like object and the display module; and a vibrator provided to the first plate-shaped object and/or the display module. The loss coefficient of the display device at 25 C. is 110.sup.2 or greater and a thickness ratio between the first plate-shaped object and the display module is from 1:10 to 10:1.

A loudspeaker system composed of a flexible panel with an affixed array of force actuators, a signal processing system, and interface electronic circuits is described. The system described is capable of creating a pattern of standing bending waves at any location on the panel and the instantaneous amplitude, velocity, or acceleration of the standing waves can be controlled by an audio signal to create localized acoustic sources at the selected locations in the plane of the panel.

A speaker device according to an embodiment includes a vibration element, a driving unit, and a panel. The driving unit applies, to the vibration element, a driving signal where a carrier wave in an ultrasonic wave band is modulated by a sound signal in an audible wave band. The panel is provided with the vibration element and arranged in such a manner that a driving signal is applied to such a vibration element by the driving unit to form a vibration region and first and second ultrasonic waves that are generated from such a vibration region and travel in mutually different directions travel toward respectively different users.

A loudspeaker system with viscoelastic material affixed between two flexible panels is disclosed. The loudspeaker system dissipates the energy of motion, resulting in less pronounced resonant peaks. The effect may be especially evident at high frequencies, where energy is dissipated over many cycles in a shorter period of time. Also disclosed are the method of making the loudspeaker system and a method of using the loudspeaker system.