Implementation of Miniaturized Microphone Unit for Implantable Hearing Aid and Its Characteristics

In this paper the miniaturized microphone unit that can be utilized to the implantable middle ear and inner ear is designed and implemented. The implantable microphone unit that planed to set up in the center of the pinna has been designed to ensure the necessary dynamic range and to improve the sensitivity of microphone unit. In addition to, the microphone unit is miniaturized and its biocompatibility of human body is considered. The microphone unit is composed of a minimized electric microphone, a titanium case which has 5.3mm diameter and 3.7mm height, a SUS316L vibrating membrane of 10 mu m thickness which is touched with a hypodermic tissue and adopted for the less attenuation of microphone sensitivity. Through the experiments of the fabricated microphone unit, it is verified that the implemented microphone unit operates up to the bandwidth of 5kHz without declining of sensitivity in the 6mm hypodermic tissue.