| 摘要 |
<P>PROBLEM TO BE SOLVED: To control emission of a sound by a speaker without using a sensor. Ž<P>SOLUTION: When the electrostatic speaker 1 is placed on a flat surface 100, acoustic emission impedance viewed from a vibrating body 10 is based upon only air present between the vibrating body 10 and an electrode 20L and air in a through-hole 21, so a low-frequency load increases and the vibrating body 10 becomes unable to vibrate even when a sound signal is input to an input portion 60, so that no sound is emitted. When the electrostatic speaker 1 is bent to separate a portion of the electrode 20L from the flat surface 100, the acoustic emission impedance viewed from the vibrating body 10 is based upon air between the vibrating body 10 and electrode 20L, air in the through-hole 21, and air between the electrode 20L and flat surface 100 at a part apart from the flat surface 100. The low-frequency load becomes small at a part turned by a hand and the vibrating body 10 vibrates to emit a sound. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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