| 摘要 |
PROBLEM TO BE SOLVED: To provide a speaker that is used for a video and acoustic equipment and has a sufficient driving force in spite of its small-sized configuration. SOLUTION: A 1st magnet 2 and a 2nd magnet 3 are provided to a lower face and an upper face of a center plate 1 in a magnetically repulsing direction, a top plate 4 is placed on the upper side of the 2nd magnet 3 and the 2nd magnet 3 and the top plate 4 is made annular, a projection 1a is provided to the upper face of the center plate 1 so as to be fitted to the 2nd magnet 3 as its structure, a torus magnet is adopted for the 2nd magnet 3 to set a high operating point without increasing the thickness of the magnet and provision of the torus top plate 4 uniformizes operating points in the magnet so as not to cause demagnetization at high temperatures and to enhance the driving force to the speaker.
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