Design And Analysis Of Bionic Microphone In The Inner Ear

Totally implantable hearing aid has advantages that traditional ones are unlikely tomatch. Problems exist in traditional hearing aid devices such as auxiliary equipmentdependence, service time limitation, handicap exposure of the patients who sufferedfrom deafness et al make these devices cannot satisfy the market demands.Development of totally implantable hearing aid is inevitable trend. But this new type ofhearing aid device involves muti-interdisciplinary advanced technology and there areplenty of practical problems remain to be solved. This work is financially supported bythe Fundamental Research Funds for the Central Universities (NO. CDJZR12280012).Implantable bionic microphone based on piezoelectric material is proposed. Mainresearch contents are as follows.1Advantages and disadvantages of traditional hearing aid devices are summarized,and the design idea of totally implantable bionic microphone based on piezoelectricmaterial has been proposed.2The structural design of the microphone is given according to travelling wavetheory. Drag force acts on rod under constant velocity flow condition is analyzed.Vibration performance of silica rod is investigated in constant flow rate, and displacementresponse of silica rod is researched.3Finite element modal of biological basilar membrane is built. Frequencyselectivity of cochlea is illustrated through modal analysis. Influence on frequencyselectivity of artificial basilar membrane of two fixed methods is researched, and thedifference of the two fixed methods is analyzed. The results are shown that a new kindof alternative material with low Young modulus which can take the place of siliconsubstrate achieving excellent performance is important.4Structure-acoustic coupling analysis of new type bionic microphone areresearched at different frequency of acoustic stimulates in both two mediums，anddisplacement diagrams of the microphone are achieved. The results show that thedisplacement decreased with the increase of frequency of acoustic stimulate when themedium is air. The vibration mode is becoming complicate when the frequency is morethan8000Hz, and there are several crests and valleys on the substrate. On the other hand,when the medium is lymph the vibration is complicate if the stimulate frequency ishigher than2000Hz, and the displacement is relatively large at low frequency. The displacement would decrease sharply after2000Hz, which would hinder futureexperimental measurement. The future work has to be focused on the improvement ofthe microphone at the frequency higher than2000Hz and provides a reference basis foroptimization design.