| 摘要 |
PURPOSE: A bone conduction speaker is provided which directly vibrates the human skull to stimulate the auditory nerve to allow the person to hear sound, thereby realizing very small-sized speaker adapted for cellular phones and telephones. CONSTITUTION: In a bone conduction speaker, a voice coil(30) is fixed onto a base plate(14) and a magnetic circuit capable of being vibrated up and down is configured of a yoke(22), a magnet(24) and an upper plate(26). A mastoid portion(16) for externally delivering sound vibration is set on the magnetic circuit. When current is applied to an electrode plate(11) of the base plate from an external power source to enter the voice coil, magnetic field is formed among the upper plate, the magnet and the yoke of the magnetic circuit and the voice coil positioned in a gap(G) of the magnetic circuit and generates an attracting force and repulsive force while the voice coil is being fixed, to vibrate the magnetic circuit up and down. A damper(20) mounted on the yoke restrains the free vibration of the magnetic circuit for maintaining uniform up and down vibration. This vibration is transmitted to the head of a person through the mastoid portion.
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