可聴骨伝導を併用した超音波ヘッドホン

When a listener's tragus is vibrated by ultrasound with amplitude modulation of audible sound, an audible sound is perceived. We have been developing an ultrasound earphone based on this interesting phenomenon. We consider that audible sound can be produced by the ultrasound transmitted from an actuator to the external auditory canal. This earphone reproduces a sufficiently loud high-frequency band sound. On the other hand, it cannot reproduce low-frequency band sound. A bone conduction earphone that actuates facial bones by audible band vibration easily leaks sound to the air in the high-frequency band. We propose a hybrid ultrasonic earphone system combined with audible band bone conduction vibration. This system enables an earphone to transmit sound that is not close to a listener's ears, and sound leakage is small. We report the structure of this system and this characteristic.