• Journal of Biomedical Engineering Research
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• v.20 no.5
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• pp.625-632
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• 1999

이식형 인공중이에 사용되는 전자트랜스듀서는 압전형 트랜스듀서에 비해 음향특성은 좋으나 부피가 크고 효율이 낮으며 수술시 정밀한 코일-자석 간격 조정이 필요하며, 최근 제안된 FMT 트랜스듀서는 외부 자장의 변화에 민감하다는 문제점이 지적되고 있다. 본 논문에서는 코일-자석 간격조정이 필요 없고 외부자장에 영향을 받지 않는 차동 플로팅메스형 전자 트랜스듀서를 제안하였다. 제안된 방식은 2개의 소형 자석을 같은 극끼리 접합함으로써 외부자장에 대해 영향을 받지 않고 효율이 높은 등의 장점을 가진다. 제안된 트랜스듀서의 진동력 및 효율에 관한 정량적인 해석을 하였으며 기존의 트랜스듀서와 비교분석을 행하였다. 그리고 공급전류에 대해 발생되는 진동력의 크기를 계산함으로서 실제 이식형 인공중이의 제작에 필요한 객관적인 설계데이타를 제시하였다. 한편, 시험 제작된 트랜스듀서의 해석결과 제안한 트랜스듀서는 기존의 FMT 트랜스듀서보다도 효율이 1.5배 정도의 향상됨을 보였으며 무부하시험 및 사체의 이소골 진동실험을 통하여 적절한 진동을 효과적으로 이소골에 전달할 수 있음을 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.68-71
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• 2000

In this study, A set-up for measuring a initial permeability of soft-ferrite powder was developed with a differential transformer coil. To measure a initial permeability of magnetic powder is cumbersome since there are not any measuring equipment and method. A magnetic powder is currently used for a magnetic fluid and microwave absorber materials, and the initial permeability of the magnetic powders is very important to be evaluated a powder for some applications.

• Journal of Sensor Science and Technology
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• v.11 no.3
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• pp.171-182
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• 2002

The differential electromagnetic transducer for IME(implantable middle ear) system, which have two small permanent magnets glued with the same pole facing each other in the coil, has high vibration efficiency and does not influenced by external magnetic field. In this paper, using finite element method, highly efficient structure of the transducer was proposed and vibration force of the transducer was calculated by electromagnetic theory. And the necessary vibration force of transducer to transmit the sound signal to inner ear when the transducer is attached at stapes was calculated and the design parameters of the transducer were investigated. Using the parameters, the differential electromagnetic transducer was manufactured in small size to implant in confined human middle ear. And it was examined by unloaded and loaded vibration experiment using temporal bone sampled from cadaver.

• The Journal of the Acoustical Society of Korea
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• v.24 no.7
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• pp.379-386
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• 2005

Among various kinds of hearing aids which have been developed so far. the conventional air conduction hearing aids have some problems such as the acoustic distortion, an howling effect due to acoustic feedback. Another type of hearing aid. the cochlear implant system can be applied to the profound imparied person. However. it shows the disadvantage that there is no possibility of recovery of the acoustic organ such as ossicle. On the other hand. the implantable middle ear heaving device directly vibratos the ossicular chain and has better sound qualify. good cosmetics for appearance. and wide frequency responses so that it can overcome the defects or the conventional hearing aids. In this paper, a mathematical modeling and a momentum equation derivation of the DET has been performed. For the optimization of the structure dimension generating maximal vibrating force of the DET. the computer simulation using a finite element analysis (FEA) software has been performed. Also. the vibrating transducer has been designed to make the frequency characteristics or the transducer be similar to those of the normal middle ear. Through the experimental results, the measured vibration characteristics of the DET has been evaluated to verify the performance for the application to implantable middle ear hearing devices.