| 摘要 |
PROBLEM TO BE SOLVED: To reduce risk of short-circuiting and electric shocks and to reduce the weight with respect to a speaker including a planar diaphragm. SOLUTION: A diaphragm 10 provided with a plurality of coils formed in a swirly wiring pattern, on a surface thereof, is disposed between a ferromagnetic fabric 20U and a nonmagnetic fabric 20L, and elastic members 30U and 30L are disposed between the diaphragm 10 and fabrics 20U and 20L. When amplitude of an acoustic signal flowing to the coils becomes positive, a magnetic field generated around the coils is strengthened and the diaphragm 10 is pulled toward the ferromagnetic fabric 20U and is displaced in a direction A. Meanwhile, when the amplitude of the acoustic signal becomes negative, the magnetic field generated around the coils is weakened, and then force pulling the diaphragm 10 toward the fabric 20U is weakened and the diaphragm 10 is displaced in a direction B by force by which the elastic member 30U is returned to an original shape. Since coils on the diaphragm, to which a current flows, are not exposed to front and rear sides, risk of short-circuiting and electric shocks is reduced. COPYRIGHT: (C)2009,JPO&INPIT
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