Star Micronics Company Limited

Hisashi Kubota

Hajime Kitamura

Shigeru Sugiyama

Naohiro Fujinami

Masami Kushida

By forming a flange portion ( ) protruding inward in the radial direction at an upper end portion ( ) of a voice coil ( ), a coiling sectional shape of the voice coil ( ) is set to a L-shape. And, the upper end portion ( ) of this voice coil ( ), is bonded and fixed to a central flat portion ( ) of a diaphragm ( ). Hereby, by only increasing slightly the weight of the usual voice coil having an I-shaped coiling section, the large bonding area can be obtained between the voice coil ( ) and the diaphragm ( ), so that separation of the voice coil ( ) can be prevented. Further, since other portions of the voice coil ( ) than the upper end portion ( ) thereof have the usual coil thickness, it is not necessary to expand the width of a cylindrical magnetic gap G in a magnetic circuit unit ( ), whereby it is prevented that electroacoustic conversion efficiency of a speaker ( ) lowers.

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Shizuoka, Japan

Hisashi Kubota