Star Micronics Company Limited

Mitsuhiro Masuda

Yoshio Imahori

Takahiro Sone

Yasunori Tsukuda

Shotaro Kamo

Eiji Matsuyama

Kazushi Suzuki

Kiyoshi Urushibata

Yoshiharu Oishi

Harunobu Tsuchiya

Earphone

An electromagnetic electroacoustic transducer, includes: a diaphragm; a magnet; an electromagnetic coil; and a casing for storing the diaphragm, the magnet and the electromagnetic coil therein. The case has at least one first sound emitting hole through which a front space on a front surface of the diaphragm in the casing communicates with a front outer space in front of the casing and at least one second sound emitting hole through which a rear space on a rear surface of the diaphragm in the casing communicates with the front outer space in front of the casing. A resonant frequency Fvof the rear space is set at a value in the range: F&#x3c;Fv&#x2266;Fvin which Fis a resonant frequency of the diaphragm, and Fvis a resonant frequency of the front space.

Electromagnetic electroacoustic transducer

A core having a coil wound thereon is fixed to a base at the bottom. The base is fixed to a case made of synthetic resin by insert molding. A diaphragm is fixed to the case in circumference, and also a magnetic flux guide member is fixed to the case in circumference. Since the diaphragm and the magnetic flux guide member is commonly fixed to the case, no variation in the distance between the diaphragm and the magnetic flux guide member would occur for every product. Further, a gap L is formed between the magnet and the magnetic flux guide member, and an air hole is formed in the magnetic flux guide member. This improves the passage of air and reduces air dumper effect without modifying the magnet in shape.

Electroacoustic transducer

An electroacoustic transducer includes a base made of a magnetic material; a magnetic core made of a magnetic material and upstanding on the base ; a diaphragm made of a magnetic material and spaced from a leading end of the magnetic core; a magnetic field generating member cooperating with the base , the magnetic core and the diaphragm to constitute a magnetic circuit, for supplying a static magnetic field; a coil placed around the magnetic core, for supplying an oscillating magnetic field to the magnetic circuit. The magnetic field generating member constitutes a multiplex ring structure in which a magnet a and a support ring are integrated together, whose faces opposing the diaphragm have respectively magnetic poles of the same polarity.

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.

Electroacoustic transducer and structure for mounting an electroacoustic transducer

An electroacoustic transducer is provided with a diaphragm which is made of a magnetic material, and to which a magnetic piece is fixed; a magnetic core which is placed in proximity to the diaphragm ; a coil which supplies an oscillating magnetic field to the magnetic core ; a housing which accommodates the diaphragm , the magnetic core , and the coil , and which has a sound release opening in a top plate opposed to the diaphragm , the sound release opening being larger than the magnetic piece . A beam portion is formed integrally with the housing which extends from a peripheral portion of the sound release opening to another peripheral portion passing above the magnetic piece . A gap Ga between the diaphragm and the magnetic core , and a gap Gb between the magnetic piece and the beam portion satisfy relationships of Ga&lE;Gb&lE;5Ga.

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Shizuoka, Japan

Mitsuhiro Masuda