Abstract: A loudspeaker diaphragm 104 affixed with a coil 103 includes an edge portion located outside of a portion affixed with the coil 103 and a center portion located inside of the portion affixed with the coil 103. The center portion is provided thereon with ribs 202. With these ribs 202, the height of the center portion can be limited to the height of the ribs 202. Therefore, it is possible to save a space of a loudspeaker where the loudspeaker diaphragm is placed, thereby slimming down the loudspeaker. Furthermore, with these ribs, the rigidity of the center portion can be improved without using a conventional solution of forming, for example, a dome shape on the center portion.

Abstract: An electromagnetic transducer, includes: a first diaphragm disposed in a vibratile manner; a second diaphragm provided in a central portion of the first diaphragm, the second diaphragm being formed of a magnetic material; a yoke disposed in a position opposing the first diaphragm; a center pole provided on a face of the yoke that opposes the first diaphragm; a coil substantially surrounding the center pole; a magnet substantially surrounding the coil; and a thin magnetic plate provided between the magnet and the first diaphragm, an inner periphery of the thin magnetic plate being in overlapping relation to an outer periphery of the second diaphragm.

Abstract: An electromagnetic transducer according to the present invention includes: a first diaphragm disposed so as to be capable of vibration; a second diaphragm disposed in a central portion of the first diaphragm, the second diaphragm being made of a magnetic material; a yoke disposed so as to oppose the first diaphragm; a center pole disposed between the yoke and the first diaphragm; a coil disposed so as to surround the center pole; a first magnet disposed so as to surround the coil; and a second magnet disposed on an opposite side of the first diaphragm from the center pole.

Abstract: A sound-driving loudspeaker system achievable with a simple structure and capable of easily improving acoustic characteristics is provided. The loudspeaker system according to the present invention emits sound by driving a diaphragm panel 14 by an electromechanical acoustic transducer 12. The loudspeaker system includes a board 10, the diaphragm panel 14 whose rim is fixedly attached to the board 19 so as to form a space 16 and which has a stiffness lower than that of the board 10, and the electromechanical acoustic transducer 12 for emitting sound into the space 16. With this structure, the diaphragm panel 14 is flexed to be vibrated by the sound emitted from the electromechanical acoustic transducer 12.

Abstract: The present invention relates to an electromagnetic electro-acoustic transducer to be used for generating an incoming indicator tone for mobile phones and the like. A resin magnet 11 is formed with a hard magnetic material and a soft magnetic material, the lowest resonant frequency can be easily set by changing the magnetic flux density in a magnetic gap by changing the compound ratio of the soft magnetic material, a high magnetic flux density is attained by increasing the magnetic permeability of the resin magnet 11 with the soft magnetic material, thus achieving a smaller size as well as a higher sound pressure through an increase in the driving force exerted to the diaphragm.

Abstract: An electromagnetic transducer includes: a first diaphragm disposed in a vibratile manner; a second diaphragm provided in a central portion of the first diaphragm, the second diaphragm being formed of a magnetic material; a yoke disposed in a position opposing the first diaphragm; a center pole provided on a face of the yoke that opposes the first diaphragm; a coil substantially surrounding the center pole; a magnet substantially surrounding the coil; and a thin magnetic plate provided between the magnet and the first diaphragm, an inner periphery of the thin magnetic plate being in overlapping relation to an outer periphery of the second diaphragm.

Abstract: A first magnet is provided in an upper case and a second magnet is provided in a lower case so that these magnets face each other. These magnets are magnetized in opposite directions. A diaphragm having a drive coil is placed between these magnets. Thus, magnetic flux emitted from the respective magnets bends in a direction approximately perpendicular to the initial direction of emission of the flux. In the magnetic field, the component of the magnetic flux in the direction of radiation proportional to the driving force is dominant, and is symmetrical relative to the direction of vibration. Therefore, the sound pressure of the reproduced sound is increased and the secondary harmonic distortion caused by asymmetry of the driving force can be reduced.

Abstract: An electric-mechanical-acoustic-transducer includes a diaphragm; a movable section; a driving section for generating a driving force for vibrating the diaphragm and the movable section; and a suppression section for suppressing a sharpness (Q factor) of a vibration force obtained by the vibration of the movable section.

Abstract: A speaker system includes a display panel for displaying an image; a transparent panel provided such that the image displayed in the display panel is viewed through the transparent panel; an electric-mechanical-acoustic-transducer having a diaphragm for outputting a sound by vibrating the diaphragm in accordance with an electric signal; and an acoustic signal transfer member for transferring the sound output from the electric-mechanical-acoustic-transducer to a space provided between the display panel and the transparent panel. The transparent panel is allowed to be vibrated by the sound transferred to the space from the electric-mechanical-acoustic-transducer via the acoustic signal transfer member.

Abstract: A speaker includes a first magnet; a second magnet provided so as to surround the first magnet; a yoke for connecting the first magnet and the second magnet; a first voice coil; a second voice coil; a first diaphragm connected to the first voice coil; a second diaphragm oppositely provided to the first diaphragm with respect to the first magnet and connected to the second voice coil; a first magnetic plate provided between the first diaphragm and the first magnet; and a second magnetic plate provided between the second diaphragm and the first magnet. The first voice coil is provided in a first magnetic gap between the first magnetic plate and the yoke. The second voice coil is provided in a second magnetic gap between the second magnetic plate and the yoke.

Abstract: An electromagnetic transducer includes: a first diaphragm; a second diaphragm provided in a central portion of the first diaphragm, the second diaphragm comprising a magnetic material having a first opening in a central portion thereof; a yoke disposed so as to oppose the first diaphragm; a center pole disposed between the yoke and the first diaphragm, wherein the center pole has a shape which allows insertion into the first opening; a coil disposed so as to surround the center pole; and a first magnet disposed so as to surround the coil.

Abstract: An electromagnetic transducer includes a magnetic member, a suspension for supporting the magnetic member at a central portion of the suspension, a diaphragm connected to the suspension, a magnet for generating magnetic flux on the magnetic member, and a coil for generating alternating magnetic flux on the magnetic member.

Abstract: An electro-mechanical-acoustic transducing device includes: an electro-mechanical-acoustic transducer which has at least one resonance frequency, for converting an input electric signal into only vibration, or into both vibration and sound; a signal supplying unit for supplying a signal in a frequency band which includes at least one of the resonance frequencies of the electro-mechanical-acoustic transducer as the input signal of the electro-mechanical-acoustic transducer; and a frequency detector for detecting a signal component having a frequency corresponding to the mechanical resonance frequency of the electro-mechanical-acoustic transducer in an electric signal which is output from the electro-mechanical-acoustic transducer, and outputting the signal component as a part of an input signal to the signal supplying unit.

Abstract: The present invention purposes to realize an electro-mechanical and acoustic transducer capable of generating both strong vibration and sound. In an electro-mechanical and acoustic transducer of the present invention, mass of a mechanical vibration system of the electro-mechanical and acoustic transducer is increased by attaching a weight to a magnetic circuit unit or integrated the weight with the magnetic circuit unit, whereby large vibration is obtained from the electro-mechanical and acoustic transducer.

Abstract: A speaker which is thin but which is capable of providing high-fidelity reproduction and ensuring a suitable level of sound pressure even when it is brought close to a wall. A closed chamber is formed behind one part of a disphragm mounted in an enclosure, and an open chamber is formed behind another part of the diaphragm. At least one voice coil driver unit is connected to the diaphragm. The phase difference between sounds radiated from the front and rear surfaces of the diaphragm is increased as large as possible by using an acoustic duct for the sound radiated through the open chamber, thereby minimizing cancellation of sounds and improving the sound pressure level.

Abstract: A speaker which is thin but which is capable of providing high-fidelity reproduction and ensuring a suitable level of sound pressure even when it is brought close to a wall. A closed chamber is formed behind one part of a diaphragm mounted in an enclosure, and an open chamber is formed behind another part of the diaphragm. At least one voice coil drive unit is connected to the diaphragm. The phase difference between sounds radiated from the front and rear surfaces of the diaphragm is increased as large as possible by using an acoustic duct for the sound radiated through the open chamber, thereby minimizing cancellation of sounds and improving the sound pressure level.

Abstract: A microwave heating apparatus for heating an object for cooking which is placed on a turntable in a heating chamber. The microwave heating apparatus is arranged so as to automatically determining an appropriate heating condition of the object on the basis of a distinctive feature such as configuration and density of the object. The distinctive feature of the object is obtained by successively measuring a distance between the center of the turntable and a surface of the object. The measurement of the distance therebetween is performed by means of an ultrasonic transducer which is provided on a wall of the heating chamber so as to transmit an ultrasonic wave to the object and receive an echo wave from the object, the distance therebetween being obtained on the basis of the time between the transmission of the ultrasonic wave and the reception of the echo wave.