Abstract: Proposed is a flextensional low-frequency sound projector including a piezoelectric actuator including a piezoelectric stack formed by stacking piezoelectric element and generating vibration in a lengthwise direction in response to an electrical signal that is input, and a stave mounted on the piezoelectric actuator in such a manner as to encompass an outer surface of the piezoelectric actuator and generating the vibration in the lengthwise direction, which is generated by the piezoelectric actuator, as vibration in a lateral direction perpendicular to the outer surface of the piezoelectric actuator, wherein the stave activates two vibration modes that use different resonance frequencies. The flextensional low-frequency sound projector that utilizes two vibration modes results from improving an existing flextensional low-frequency sound projector that is driven in a single vibration mode and thus has a narrow frequency bandwidth.

Abstract: The present invention relates to a sensor that uses a sensing mechanism having a combined static charge and a field effect transistor, the sensor including: a substrate; source and drain units formed on the substrate and separated from each other; a channel unit interposed between the source and drain units; a membrane separated from the channel unit, disposed on a top portion and displaced in response to an external signal; and a static charge member formed on a bottom surface of the membrane separately from the channel unit and generating an electric field.

Abstract: The present invention relates to a sensor that uses a sensing mechanism having a combined static charge and a field effect transistor, the sensor including: a substrate; source and drain units formed on the substrate and separated from each other; a channel unit interposed between the source and drain units; a membrane separated from the channel unit, disposed on a top portion and displaced in response to an external signal; and a static charge member formed on a bottom surface of the membrane separately from the channel unit and generating an electric field.

Abstract: A sound generator includes a transducer converting electric energy to mechanical energy, a mechanical amplifier mechanically amplifying a vibration generated in a piezoelectric component of the transducer, and a radiation plate radiating a sound wave from a signal amplified by the mechanical amplifier, wherein the radiation plate includes a first step having a height for compensating for a first resonance frequency and a second step having a height for compensating for a second resonance frequency.

Abstract: A sound generator includes a transducer converting electric energy to mechanical energy, a mechanical amplifier mechanically amplifying a vibration generated in a piezoelectric component of the transducer, and a radiation plate radiating a sound wave from a signal amplified by the mechanical amplifier, wherein the radiation plate includes a first step having a height for compensating for a first resonance frequency and a second step having a height for compensating for a second resonance frequency.