A display device is disclosed. The display device includes a display panel, a vibration plate, and an actuator structural layer. The vibration plate is attached to a side of the display panel. The actuator structural layer is disposed on the vibration plate.

An object is to provide a piezoelectric film that has excellent flexibility in a high temperature environment at higher than 50° C. and exhibits good flexibility even at room temperature, a laminated piezoelectric element in which the piezoelectric films are laminated, and an electroacoustic transducer using the piezoelectric film or the laminated piezoelectric element. The object is solved by the piezoelectric film including: a polymer-based piezoelectric composite material in which piezoelectric particles are dispersed in a matrix including a polymer material; and electrode layers provided on both surfaces of the polymer-based piezoelectric composite material, in which a loss tangent at a frequency of 1 Hz according to dynamic viscoelasticity measurement has a maximal value of greater than or equal to 0.1 existing in a temperature range of higher than 50° C. and lower than or equal to 150° C., and has a value of greater than or equal to 0.08 at 50° C.

An object is to provide a piezoelectric film that has excellent flexibility in a sub-zero environment and exhibits the required flexibility even at room temperature, a laminated piezoelectric element in which the piezoelectric films are laminated, and an electroacoustic transducer using the piezoelectric film or the laminated piezoelectric element. The object is solved by the piezoelectric film including: a polymer-based piezoelectric composite material in which piezoelectric particles are dispersed in a matrix including a polymer material; and electrode layers formed on both surfaces of the polymer-based piezoelectric composite material, in which a loss tangent at a frequency of 1 Hz according to dynamic viscoelasticity measurement has a maximal value of greater than or equal to 0.1 existing in a temperature range of higher than or equal to −80° C. and lower than 0° C., and has a value of greater than or equal to 0.05 at 0° C.

A crossover circuit, disposed within a sound producing device including a first sound producing cell driven by a first driving signal and a second sound producing cell driven by a second driving signal, includes a first filter receiving an input signal at an input terminal of the first filter, a first subtraction circuit, and a second filter coupled between the output terminal of the first filter and the second input terminal of the first subtraction circuit. A first input terminal of the first subtraction circuit is coupled to the input terminal of the first filter; a second input terminal of the first subtraction circuit is coupled to an output terminal of the first filter. The crossover circuit produces the first driving signal and the second driving signal according to a first output signal of the first subtraction circuit and a second output signal of the first filter respectively.

A display apparatus includes: a display module including a display panel configured to display an image, a vibration plate on a rear surface of the display module, a connection member between the rear surface of the display module and the vibration plate, at least one vibration module on the vibration plate, and an enclosure between the display module and the vibration plate, the enclosure being spaced apart from the vibration module, the enclosure surrounding the vibration module.

A method, system and devices to selectively control modal vibrations in an elastic panel with a number of force actuators distributed throughout the surface of the elastic panel to excite/depress the response of one or more vibrational resonant modes included in a prescribed subset. The force actuators are disposed such that prescribed modal excitation/depression may be realized when the actuators are driven by a common source signal.

A sound generating apparatus for vehicles may include a sound generating device to be covered by a vehicle interior material of a vehicle. The sound generating device may be configured to vibrate the vehicle interior material. A vehicle including the sound generating apparatus for vehicles may include a vehicle interior material, covering a vehicle structure, and at least one sound generating apparatus disposed at the vehicle interior material. The vehicle interior material may vibrate according to a vibration of the sound generating apparatus to output a sound.

A speaker includes a first flat diaphragm, an actuator that applies vibration corresponding to a sound signal to the first flat diaphragm, and a second flat diaphragm separated from the first flat diaphragm and vibrated by the actuator.

A speaker includes: a vibration plate, a piezoelectric member on a surface of the vibration plate, and a first adhesive member between the vibration plate and the piezoelectric member, wherein: the piezoelectric member is a unimorph piezoelectric member, and the first adhesive member has a high elastic modulus, or the piezoelectric member is a bimorph piezoelectric member, and the first adhesive member has a low elastic modulus.

A sound producing device includes at least one air pulse generating element. Each of the at least one air pulse generating element includes a membrane, a first air chamber and at least one opening, wherein a chamber pressure exists in the first air chamber. The membrane is actuated to change the chamber pressure of the first air chamber to generate a plurality of air pulses, the air pulses are propagated through the at least one opening, the air pulses produce a non-zero offset in terms of sound pressure level, and the non-zero offset is a deviation from a pressure value of an ambient pressure outside the sound producing device.