Abstract: The present invention relates to a loudspeaker in the acoustic field and the information communication field. The invention provides a loudspeaker that can realize a thinner size. To achieve this, the loudspeaker of the present invention is structured so that a part of a diaphragm is inserted to a dent or an opening formed at the center poles of a lower plate of a magnetic circuit. This structure allows the diaphragm to be stored within the height of the magnetic circuit, thus allowing the loudspeaker to have a thinner size.

Abstract: The present invention relates to a loudspeaker in the acoustic field and the information communication field. The invention provides a loudspeaker that can realize a thinner size. To achieve this, the loudspeaker of the present invention is structured so that a part of a diaphragm is inserted to a dent or an opening formed at the center poles of a lower plate of a magnetic circuit. This structure allows the diaphragm to be stored within the height of the magnetic circuit, thus allowing the loudspeaker to have a thinner size.

Abstract: An electroacoustic transducer has a magnetic circuit, a frame combined with the magnetic circuit, a diaphragm combined with a periphery of the frame, a voice coil, a terminal, and a holder covering the frame. The voice coil is combined with the diaphragm and a part of the voice coil is arranged in a magnetic gap of the magnetic circuit. The terminal, made of a metal plate having spring property and electric conductivity, electrically connects an outside circuit and the voice coil utilizing spring pressure generated when the metal plate is bent. The holder forms a stopper for restricting a bend of the metal plate forming the terminal to within a reversible limit of a metallic material.

Abstract: An edge (29) for supporting a diaphragm assembly (100) with respect to a frame (26) is bonded to the frame (26) along the outer periphery thereof and joined to a diaphragm (27) in a position more peripherally inward than a voice coil (28) along the inner periphery thereof. The edge (29) partly overlaps diaphragm (27). This structure allows downsizing of the speaker, without reducing the sizes of a permanent magnet (21) and the edge (29).

Abstract: A loudspeaker includes a diaphragm, a voice coil fixed to the diaphragm, a first magnet having a first pole surface facing an inner side of the voice coil, a second magnet located inside the inner side of the voice coil, and a first magnetic fluid provided between the first pole surface of the first magnet and the voice coil. The first magnet has the first pole surface facing the inner side of the voice coil. The second magnet has a second pole surface located inside the inner side of the voice coil such that a magnetic flux passing through the first pole surface of the first magnet crosses the voice coil in a direction perpendicular to the voice coil and a vibration direction. The first magnetic fluid contacts the first pole surface and the voice coil. The loudspeaker has a small thickness but can produce a high audio output, while preventing rolling.

Abstract: A voice coil wound to have a loop having an inner side is fixed to a diaphragm vibrating in a vibration direction. A first magnet having a first pole surface is fixed to an upper case. A second magnet having a second pole surface is fixed to a lower case. A first magnetic fluid is attached to the first pole surface of the first magnet after fixing the first magnet to the upper case. The diaphragm is fixed to the upper case after fixing the voice coil to the diaphragm and after attaching the first magnetic fluid to the first pole surface of the first magnet, such that the first pole surface of the first magnet faces the inner side of the voice coil and that the first magnetic fluid is provided between the first pole surface of the first magnet and the voice coil and contacts the first pole surface and the voice coil.

Abstract: A loudspeaker includes a magnetic circuit having a magnetic gap, a frame coupled to the magnetic circuit, a voice coil having a first end positioned in the magnetic gap and a second end opposite to the first end, and a diaphragm coupled to the second end of the voice coil and the frame. The voice coil has a center axis provided through the first end and the second end. The diaphragm has a first portion in which the center axis of the voice coil is provided. The first portion of the diaphragm is provided inside the voice coil. The diaphragm further has a second portion outside the voice coil. One of the first portion and the second portion of the diaphragm has a cross section in a plane including the center axis, and the cross section of the one of the first portion and the second portion of the diaphragm has an elliptic-arc shape. This loudspeaker has a small thickness, has a high sound pressure level in a high frequency range, and secures a wide reproduction range in high frequencies.

Abstract: An edge (29) for supporting a diaphragm assembly (100) with respect to a frame (26) is bonded to the frame (26) along the outer periphery thereof and joined to a diaphragm (27) in a position more peripherally inward than a voice coil (28) along the inner periphery thereof. The edge (29) partly overlaps diaphragm (27). This structure allows downsizing of the speaker, without reducing the sizes of a permanent magnet (21) and the edge (29).

Abstract: A net made of material containing at least metal is bonded to a protector of a loud speaker, and hence shields electromagnetic waves. Electromagnetic interference can be prevented in an electronic apparatus such as a portable phone employing the loud speaker.

Abstract: There is provided a speaker device in which a baffle plate that forms an acoustic space is formed of a resin material, and a step is provided at an opening for fixing a diaphragm in this baffle plate so that the diaphragm is positioned by this step. It is thereby possible to improve strength of the baffle plate and strength of the speaker device.

Abstract: An edge (29) for supporting a diaphragm assembly (100) with respect to a frame (26) is bonded to the frame (26) along the outer periphery thereof and joined to a diaphragm (27) in a position more peripherally inward than a voice coil (28) along the inner periphery thereof. The edge (29) partly overlaps diaphragm (27). This structure allows downsizing of the speaker, without reducing the sizes of a permanent magnet (21) and the edge (29).

Abstract: A net made of material containing at least metal is bonded to a protector of a loud speaker, and hence shields electromagnetic waves. Electromagnetic interference can be prevented in an electronic apparatus such as a portable phone employing the loud speaker.

Abstract: A loudspeaker used mainly for mobile communication equipment such as a mobile telephone and having two loudspeaker parts provided in one frame is provided. In the loudspeaker, a yoke has a groove portion and a second voice coil disposed in this groove portion drives a second diaphragm. Since the groove portion functioning as a magnetic gap is formed by processing the yoke, variation in the magnetic gap, which conventionally occurred at the time of incorporation, is eliminated and accuracy is improved, thus stabilizing the sound pressure frequency property.

Abstract: The present invention relates to a loudspeaker in the acoustic field and the information communication field. The invention provides a loudspeaker that can realize a thinner size. To achieve this, the loudspeaker of the present invention is structured so that a part of a diaphragm is inserted to a dent or an opening formed at the center poles of a lower plate of a magnetic circuit. This structure allows the diaphragm to be stored within the height of the magnetic circuit, thus allowing the loudspeaker to have a thinner size.

Abstract: An electro-acoustic transducer wherein a stopper of a terminal is composed of an elastic body having an impulsive-force resistance and an excellent resilience. The stopper is mounted on the yoke or lower plate of magnetic circuit, which is made of a metallic material having an impulsive-force resistance. In this way, the stopper can restrict the terminal within the reversibility limit value of the spring force of the metallic material, and hence can enhance the reliability.

Abstract: An electroacoustic transducer has a magnetic circuit, a frame combined with the magnetic circuit, a diaphragm combined with a periphery of the frame, a voice coil, a terminal, and a holder covering the frame. The voice coil is combined with the diaphragm and a part of the voice coil is arranged in a magnetic gap of the magnetic circuit. The terminal, made of a metal plate having spring property and electric conductivity, electrically connects an outside circuit and the voice coil utilizing spring pressure generated when the metal plate is bent. The holder forms a stopper for restricting a bend of the metal plate forming the terminal to within a reversible limit of a metallic material.