Abstract: A low cost dynamic speaker 10 which effectively prevents damage of the diaphragm 16 when the speaker 10 is mounted on the printed circuit board 2. The insulating ring 22 is attached to the front surface of the diaphragm 16 at the periphery. The insulating ring 22 has a pair of terminal pins 24 supported thereon for continuity of the lead wire 18a with the conductor 4 of the printed circuit board 2. The conducting portion 24b of each of the terminal pins 24 is protruded forward beyond the annular flat surface 22a of the insulating ring 22. Compared with the conventional terminal pin having the shape of a letter of “J” for continuity with the conductor 4 of the printed circuit board 2, the terminal pin 24 of the present invention is simply formed to be straight and short, thus contributing to reduction in cost of the speaker 10. Further, when the speaker 10 is mounted on the printed circuit board 2, the front side of the speaker 10 faces the printed circuit board 2.

Abstract: A speaker holder for a speaker mounted on a printed circuit board. The speaker holder 50 comprises the speaker engagement portion 52 abutting the bottomed cylindrical portion 26A of the frame 26 of the speaker 10 and a plurality of engagement legs 54 extending from the speaker engagement portion 52. The speaker 10 is put tightly between the speaker engagement portion 52 and the printed circuit board 2 and fixed thereto via the engagement legs 54. Compared with the conventional speaker holder having separate structures for retaining the speaker and for fixing the holder to the printed circuit board 2, the mounting height of the holder 50 in state where the speaker 10 is mounted on the printed circuit board 2 via the holder 50 is considerably lowered. Further, the holder 50 is of a simple structure since a structure for retaining a speaker is not required.

Abstract: An electromagnetic receiver of a balanced armature type is employed as a receiver to be mounted in a portable telephone. The balance armature receiver has lower power consumption and higher electric acoustic conversion efficiency. The balanced armature receiver provides a required output even though small in size. The receiver occupies a considerably reduced space in the portable telephone, compared with a conventional portable telephone having a conventional dynamic receiver. The longitudinal wall of the receiver is parallel to the upper edge of a liquid crystal display panel, so that the liquid crystal display panel is extended upward and considerably enlarged.

Abstract: A capacitor microphone includes a case having an end wall defining an opening for a sound hole, a capacitor portion comprising a diaphragm, a back plate and a spacer, the diaphragm opposing to the back plate via the spacer, the capacitor portion being accommodated in the case in such an manner as the diaphragm is placed on the side of the end wall, and a substrate accommodated in the case farther from the end wall than the capacitor portion, the substrate having an impedance conversion element mounted on a surface thereof facing the capacitor portion. A communicating opening is provided around the back plate in a position opposing to the impedance conversion element for communicating spaces on the front and back sides of the back plate. The communicating opening has a larger area than that of the top of the impedance conversion element to allow the spaces on both sides of the back plate to communicate with each other.

Abstract: There is provided an electroacoustic transducer 1 comprising a base 24 made of magnetic material, a magnetic core 22 made of magnetic material and provided erectly on the base 24, a diaphragm 20 made of magnetic material and supported with a gap between the diaphragm and a forward end of the magnetic core, a magnet 25 constituting a magnetic circuit together with the base 24, the magnetic core 22 and the diaphragm 20 so as to provide a magnetostatic field, a coil 23 disposed around the magnetic core for applying an oscillating magnetic field to the magnetic circuit, a coil bobbin 30 for holding the coil 23, a housing 10 for receiving the above-mentioned members, a filler 19 applied to an external surface side of the base 24, and lead terminals 41 and 42 for supplying an electric current. The lead terminals 41 and 42 have protrusion portions 41a and 42a, respectively, protruding into an internal surface side of the base 24 in the axial direction of the coil.

Abstract: A frame 14 supporting a diaphragm 12 by its outer periphery is constructed by a connecting ring 30—which is formed in an annulus following the shape of the outer periphery of diaphragm 12—to base 28 which comprises a bottomed cylinder portion 28A and a mounting portion 28B which extends radially outward from the bottomed cylinder portion 28A which is a part of the magnetic circuit unit 18. The connection is achieved by the caulking of the ring 30 and the mounting portion 28B with the diaphragm 12 clamped therebetween.

Abstract: An electroacoustic transducer to be mounted on a board of a device, includes an anode conductive part which is in press contact with the board of the device, and a cathode conductive part which is in press contact with the board of the device, wherein the anode conductive part and the cathode conductive part are respectively placed at an axial center position or at predetermined positions in a radial direction to eliminate directionality in a circumferential direction.

Abstract: Fixing of a voice coil 16 to a diaphragm 12 is performed by caulk-fixing a coil supporting member 26 to the diaphragm 12 and by fit-supporting the voice coil 16 by the coil supporting member 26. Hereby, the voice coil 16 is physically fixed to the diaphragm 12 and its fixing strength is heightened. The caulk-fixing is performed by subjecting a caulking projection of the coil supporting member 26 to a plastic deformation thereby to provide a caulk-fixed portion 26b, whereby deformation injurious to the acoustic property does not occur in the diaphragm 12. Further, the fit-supporting is performed by interposing a flange portion 16a1 formed at an upper end portion 16a of the voice coil 16 between an engaging engaging portion 26a of the coil supporting member 26 and a central flat portion 12b of the diaphragm 12 and holding it by them from upper and lower sides.

Abstract: An electroacoustic transducer, which has a diaphragm, a support member for supporting the diaphragm, a pole piece placed inside the support member and comprising a core and a base, a coil wound around the core, and a magnet placed between the support member and the coil, in which the diaphragm is made of resin to which a magnetization is applied.

Abstract: An electroacoustic transducer, which has a diaphragm, a support member for supporting the diaphragm, a pole piece placed inside the support member and comprising a core and a base, a coil wound around the core, and a magnet placed between the support member and the coil, in which the pole piece or at least the core thereof is made of resin to which a magnetization is applied.

Abstract: In an electroacoustic transducer having an outer case integral with lead terminals and a drive section including a coil disposed in the outer case with both coil terminals of the coil being led out on and connected to lands of the lead terminals, the lands are formed in approximately circular shapes.

Abstract: The invention provides an electroacoustic transducer capable of preventing degradation in its acoustic performance as a result of the reflow soldering process applied. With the electroacoustic transducer, variation in the minimum resonance frequency Fo of a diaphragm is restrained, stabilizing the acoustic performance by causing a decrease in the minimum resonance frequency Fo of the diaphragm due to irreversible demagnetization of the magnet caused by the reflow soldering temperatures to cancel out an increase in the minimum resonance frequency Fo of the diaphragm due to thermal contraction of a holder member caused by the reflow soldering temperatures.

Abstract: The present invention provides an electroacoustic transducer which realizes an optimum characteristic thereof utilizing heat caused by reflow soldering without being influenced by the same heat. The electroacoustic transducer includes a magnetic driving portion composed of a base, a core provided upright on the base and a coil wound around the core, wherein a height of the coil at the manufacturing time is set lower by a height which corresponds to thermal expansion of the coil in reflow soldering, and a projection length of the core exposed from the coil at the manufacturing time is set larger by the height which corresponds to thermal expansion of the coil in reflow soldering.

Abstract: The present invention provides a small electroacoustic transducer which is improved in sound characteristic by enlarging and adjusting a volume of a resonance space. A second resonant chamber as an auxiliary space is formed relative to a first resonant chamber formed in front of a resonance plate, wherein the first and second resonant chambers are connected with each other to enlarge the volume of the resonant volume.

Abstract: An electroacoustic transducer, which has a case, a base located in the case, a core attached to the center of the base, a coil wound around the core, a magnet placed around the coil with a clearance formed in between with one end of the magnet is supported by the base, a support member located around the magnet for supporting an elastic plate, and a magnet support portion provided in the support member for supporting the other end of the magnet.

Abstract: The present invention provides an electroacoustic transducer and a method of fabricating the same, employing a lead frame to integrally form a plurality of component parts, thus reducing the number of individual component parts, and improving assembly efficiency. The electroacoustic transducer comprises a base, a yoke fixed to the base, a core, a coil wound around the core, magnet surrounding the coil, a support ring surround the magnet, a vibrating plate supported on the support ring, lead terminals fixed to the base, and a case having a sound emitting cylinder and joined to the base so as to cover those components. A gap is formed between the core and the diaphragm. The diaphragm, the gap, the core, the yoke and the magnet form a closed magnetic path. The coil drives the diaphragm for vibration when energized. The yoke and the lead terminals are integrally formed of a common metal material such as the lead frame. The core may be integrally formed with the yoke of the lead frame.

Abstract: An electroacoustic transducer, which has a lead frame previously formed into a predetermined shape, an outer case formed integrally with the lead frame and a drive section including a coil arranged inside the outer case, comprises an opening formed in the outer case; lands formed by exposing a part of the lead frame through an outer surface of the outer case; and the coil having coil terminals led out of the outer case through the opening and connected to the lands.