Abstract
In our previous research, a new subcutaneously implanted bone conduction hearing aid has been proposed. The hearing aid is composed of an external unit and an internal unit. The external unit consists of a microphone, a sound processor and a transmitting coil. The internal unit consists of a receiving coil and a vibrator. The vibrator is made of giant magnetostrictive material (GMM) which deforms its length in response to change of surrounding magnetic field. The internal unit is embedded under the skin and vibrates the temporal bone when the magnetic flux is supplied by the external unit. Prototype vibrators have been developed, but excitation force of the prototypes was inadequate especially in low frequency range. In this study, the shape of the vibrator case was improved to enhance the excitation force. The new-type vibrator has a high output at all frequencies compared with the conventional prototype. To consider the shape of slit which has the quality to last long and high output is an issue in the future.
