| 摘要 |
PROBLEM TO BE SOLVED: To provide hi-fi/high output linear motor type speaker suitable for low-pitched sound reproduction. SOLUTION: A cylindrical magnet 14 having outside dimension slightly smaller than cavity dimension is arranged in the cavity of a cylindrical electromagnet 10. In the magnet 14, the outside and the inside are considered as first and second magnetic poles with the opposite polarity to each other and a diaphragm 16 is attached so as to interrupt airflow in the cavity of the magnet 14. Coil groups other than one coil group among many coil groups 12 is energized so as to perform magnetic levitation of the magnet 14 by making the inside of the electromagnet 10 a magnetic pole with the same polarity as that of the second magnetic pole and one coil group is energized so as to reverse the polarity of the magnetic pole from other coil group. Switching control of direction of current of a plurality of coil groups is performed so as to vibrate the diaphragm 16 by performing reciprocating displacement of the magnet 14 while being magnetically levitated by a magnetic pole relative to polarity reversal in accordance with amplitude variation of an audio signal. COPYRIGHT: (C)2007,JPO&INPIT
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