Verification of vibration characteristic of hermetically sealed differential floating mass transducer for implantable middle ear hearing device using mock-up of ear

Several types of implantable middle ear hearing devices (IMEHDs) have been developed to overcome disadvantages of the conventional hearing aids. IMEHDs are divided into three parts which are a microphone, a signal processing unit, and a vibration transducer. In particular, the vibration transducer is very important component because it directly generates the mechanical vibration in the ossicles so that the input sound can be delivered to the inner ear. As one of the vibration transducer for IMEHDs, a differential floating mass transducer (DFMT) has been developed in Korea. However, the study for the DFMT has focused on the improvement in vibration efficiency until now. In this paper, the hermetically sealed DFMT for implantation is implemented and its vibration characteristic is measured. Then, the vibration characteristic of the DFMT is also compared with that of the stapes displacement defined by ASTM. Through the comparison, it is verified that the implemented DFMT has proper vibration displacement.