| 摘要 |
PROBLEM TO BE SOLVED: To obtain an active noise control function for reducing noise components by transmitting vibrational energy obtained by arc electro-acoustic conversion system through a lever for vibration transmission to an ear plug member, and vibrating the ear plug member for allowing a user to sense this as an acoustic signal. SOLUTION: A signal in an audible frequency band is inputted to an electric signal input terminal Ein. The electric signal is inputted to a vibrator 11, and converted into vibrational energy according to the level of the electric signal. The vibrational energy is transmitted through the bulk vibration of a lever 12 to an ear plug member 20. This ear plug member 20 generates acoustic energy to a small air chamber 100 formed of the ear plug member 20, external auditory meatus 80, and eardrum 90. The eardrum 90 is excited by the acoustic energy so as to be sensed as a sound by a human being, and a functional operation as an earphone can be performed. Also, the ear plug member 20 whose flexibility is high is used so that a clearance between the external auditory meatus 80 and the ear plug member 20 can be minimized, and the leakage of the acoustic energy can be reduced to almost zero.
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