Abstract: Provided are an actuator, method for manufacturing the actuator, and acoustic transmitter having the actuator. The actuator includes: an elastic metal member having a plurality of curved segments and a plurality of connection segments which constitute a ring structure with a long-axis direction and a short-axis direction; a multilayer piezoelectric member disposed within the ring structure and having a plurality of stacked piezoelectric units along the long-axis direction; and a plurality of coupling members disposed within the ring structure, wherein the multilayer piezoelectric member has two ends in the long-axis direction that are coupled to the connection segments of the elastic metal member in the long-axis direction. A preload stress is imparted to the elastic metal member. A plurality of coupling members having a size corresponding to the preload stress are disposed between the elastic metal member and the multilayer piezoelectric member.

Abstract: Provided are an actuator, method for manufacturing the actuator, and acoustic transmitter having the actuator. The actuator includes: an elastic metal member having a plurality of curved segments and a plurality of connection segments which constitute a ring structure with a long-axis direction and a short-axis direction; a multilayer piezoelectric member disposed within the ring structure and having a plurality of stacked piezoelectric units along the long-axis direction; and a plurality of coupling members disposed within the ring structure, wherein the multilayer piezoelectric member has two ends in the long-axis direction that are coupled to the connection segments of the elastic metal member in the long-axis direction. A preload stress is imparted to the elastic metal member. A plurality of coupling members having a size corresponding to the preload stress are disposed between the elastic metal member and the multilayer piezoelectric member.

Abstract: A piezoelectric electroacoustic transducer is disclosed. The piezoelectric electroacoustic transducer includes a diaphragm, a piezoelectric element disposed on the diaphragm, an elastic element connected with and around the diaphragm, a frame around the elastic element and being disassembled so as to adjust an inner-frame projected area of the frame, and a buffer interposed between the elastic element and the frame, wherein the frame has an inner-frame projected area less than a planar projected area of the diaphragm, the elastic element, and the buffer, such that the frame always provides a compressive stress to the diaphragm, the piezoelectric element, the elastic element, and the buffer. The piezoelectric electroacoustic transducer may be implemented as a loudspeaker or a microphone.

Abstract: A piezoelectric electroacoustic transducer is provided, including a three-dimensional structure, at least a piezoelectric element, and at least a membrane. The three-dimensional structure is formed to have a top portion and a side portion integrally connected to the top portion by press molding a plate. The side portion has at least a gap and is separated into a plurality of pillars by the at least a gap. The at least a piezoelectric element is disposed on the top portion, and the at least a membrane covers the at least a gap of the side portion. The piezoelectric electroacoustic transducer in the present disclosure is capable of being implemented as a loudspeaker or a microphone.

Abstract: A piezoelectric electroacoustic transducer is disclosed. The piezoelectric electroacoustic transducer includes a diaphragm, a piezoelectric element disposed on the diaphragm, an elastic element connected with and around the diaphragm, a frame around the elastic element and being disassembled so as to adjust an inner-frame projected area of the frame, and a buffer interposed between the elastic element and the frame, wherein the frame has an inner-frame projected area less than a planar projected area of the diaphragm, the elastic element, and the buffer, such that the frame always provides a compressive stress to the diaphragm, the piezoelectric element, the elastic element, and the buffer. The piezoelectric electroacoustic transducer may be implemented as a loudspeaker or a microphone.

Abstract: A piezoelectric electroacoustic transducer is provided, including a three-dimensional structure, at least a piezoelectric element, and at least a membrane. The three-dimensional structure is formed to have a top portion and a side portion integrally connected to the top portion by press molding a plate. The side portion has at least a gap and is separated into a plurality of pillars by the at least a gap. The at least a piezoelectric element is disposed on the top portion, and the at least a membrane covers the at least a gap of the side portion. The piezoelectric electroacoustic transducer in the present disclosure is capable of being implemented as a loudspeaker or a microphone.

Abstract: An improved PTC electric heating element assembly comprises a heating element of a ceramic material with positive temperature coefficient, two insulating elements with different thickness, and four metal sheets, which are arranged in a stack to firmly join together by a fastening means fixed on the bottom of a container. The opposite sides of the heating element are contacted by metal sheets having electrodes which are connected to electric wires to effectively conduct the heat produced to the container.