• 전자공학회논문지SC
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• 제41권5호
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• pp.71-78
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• 2004

체내에 이식되는 완전 이식형 인공중이 시스템의 제어를 위해 저전력 마이크로프로세서인 MSP430을 이용한 적외선 리모컨형 외부제어기를 설계하였고, 수신된 신호 해석을 위한 제어 알고리즘을 설계하여 전원 ON/OFF와 소리크기 UP/DOWM 동작을 수행하도록 하였다. 먼저 피부 투과시 발생하는 적외선 신호의 반사 및 투과모델을 이용하여 시스템에 필요한 적외선 LED 방사강도를 계산하고, 인반 적외선 리모컨과의 오작동을 방지하기 위해 고유의 데이터 프로토콜을 설정하였다. 이식되는 수신부의 적외선 수신모듈은 자체 소비전류를 줄이기 위해 마이크로프로세서의 내부 타이머에 의한 25% 듀티비를 갖는 출력신호를 전원으로 사용하였다. 4mm 두께의 돼지피부를 이용한 피부투과 전송실험을 실시하여 구현된 송수신 장치로 신호가 전달됨을 확인하였다.

• 재활복지공학회논문지
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• 제5권1호
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• pp.59-64
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• 2011

인공 중이 (IMEHD, implantable middle ear hearing device)용 플로팅 매스 트랜스듀서는 제작 과정상에서 발생하는 구조적 오차 및 제작 결합시의 문제점들로 인해 설계 시 의도와 다른 진동 특성을 가질 수 있게 되고, 이렇게 제작된 진동 트랜스듀서는 향후 실제 환자에게 이식되었을 때의 진동체 진동 성능을 예측하기 어려운 문제점이 있다. 본 연구에서는 제작된 플로팅 매스형 트랜스듀서에 대해 설계값과의 비교 평가 및 향후 컴퓨터 모델화된 청각 중이 집중 소자 모델에 적용이 가능하도록 기 제작된 진동체의 집중 소자 모델 파라미터들을 추정할 수 있는 방법을 제안하였으며, 제안된 방법을 LabVIEW 기반의 그래픽 유저 인터페이스 소프트웨어로 구현하였다. 제안된 방법은 실제 제작된 플로팅 매스형 진동체의 진동 변위 및 위상 데이터를 이용하여 해당 진동체의 집중 모델 파라미터들을 순차적 이차 프로그래밍 (SQP, sequential quadratic programming) 방법으로 추정하는 방식이다. 구현된 방법을 이용하여 측정 데이터에 가해지는 잡음의 양에 따른 플로팅 매스형 진동 트랜스듀서의 집중 모델 파라미터 추정 시의 발생 오차 변화를 컴퓨터 시뮬레이션을 통해 조사하여 본 방법의 파라미터 추정 정확도를 확인하였다. 또한, 실제로 제작한 인공중이용 진동 트랜스듀서에 대해 측정된 진동 변위 및 위상 데이터를 이용하여 진동체의 집중 모델 파라미터들을 추정하였으며, 기존 설계값들과 비교를 통해 제안된 방법의 유용성을 평가하였다.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.375-385
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• 2016

Recently, several implantable hearing aids such as cochlear implant, middle ear implant, etc., which have a module receiving power and signal from outside the body, are frequently used to treat the hearing impaired patients. Most of implantable hearing aids are adopted permanent magnet pairs to couple between internal and external devices for the enhancement of power transmission. Generally, the internal device which containing the magnet in the center of receiving coil is implanted under the skin of human temporal bone. In case of MRI scanning of a patient with the implantable hearing aid, however, homogeneous magnetic fields of the MRI might be interfered by the implanted magnet. For the above reasons, the MR image is degraded by large area of artifact, so that diagnostics are almost impossible in deteriorated region. In this paper, we proposed an external coil system that can reduce the artifact of MR image due to the internal coupling magnet. By finite element analysis estimating area of MR artifact according to varying current and shape of the external coil, optimal coil parameters were extracted. Finally, the effectiveness of the proposed external coil system was verified by confirming the artifact at real MRI scan.

• 한국음향학회지
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• 제24권3호
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• pp.127-132
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• 2005

이식형 인공중이용 트랜스듀서는 주파수 특성 및 구동 성능이 우수해야 하고 크기가 작아야 한다. 이러한 트랜스듀서로서 단결정 압전 재료인 PMN-PT를 이용한 적층형 액츄에이터를 제안하였고, 유한요소해석 및 제작실험을 통해 그 타당성을 밝혔다. 실험에서는 두께 $0.2{\cal}mm$를 갖는 시편을 14층으로 쌓아 최종적으로 $1{\cal}mm{\times}1{\cal}mm{\times}2.8{\cal}mm$ 크기의 PMN-PT 적층형 액츄에이터를 제작하였다. 제작된 PMN-PT 액츄에이터의 성능은 Impedance Spectrum과 구동변위 측정을 통해 PZT 액츄에이터와 비교, 평가하였고, 이를 통해 단결정 재료인 PMN-PT를 이용할 경우 우수한 성능의 인공중이용 액츄에이터 제작이 가능함을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.162-168
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• 2009

Implantable middle ear hearing devices (IMEHDs) have been widely studied as an alternative hearing aids to solve the problems of conventional hearing aids. Vibration transducer of middle ear hearing aids is a key component because vibration characteristics of transducer is directly involved performance of hearing aids. So, the study about middle ear hearing aids concentrate on the transducers. A floating mass type transducer is most efficient. In this paper, we suggest a lumped mechanical model of electromagnetic floating mass transducer implanted on human middle ear. The proposed model enables analysis of the vibration characteristics of a floating mass transducer and prediction of the variation after implant on ossicle that offers a simple and easy to analyze. The parameters was drawn based on the components and the structures of transducer. The Lumped mechanical model was converted by the electrical-mechanical equivalent model, and simulated using PSpice. So, we investigated vibration characteristics of transducer influenced it's components. And we predict vibration characteristics of stapes footplate due to implanted transducer's vibration using combining model of transducer and human ear. To prove the feasibility of the suggested model, we fabricated a differential floating mass transducer (DFMT) as one of floating mass transducers and performed experiments using the human temporal bones.

• 센서학회지
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• 제27권2호
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• pp.99-104
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• 2018

A micro electromagnetic actuator with high vibration efficiency is proposed for use in an implantable hearing device. The actuator, which can be implanted in the middle ear, consists of membranes based on the stainless steel 304 (SUS-304), and other components. In conventional actuators, in which a thick membrane and a silicone elastomer are used, the size reduction was difficult. In order to miniaturize the size of the actuator, it is necessary to reduce the size of the actuation potion that generates the driving force, resulting in reduction of the electromagnetic force. In this paper, the electromagnetic actuator is further miniaturized by the metal membrane and the vibration amplitude is also optimized. The actuator designed according to the simulation results was fabricated by using micro-electro-mechanical systems (MEMS) technology. In particular, a $20{\mu}m$ thick metal membrane was fabricated using the erosion process, which reduced the length of the actuator by more than $400{\mu}m$. In the experiments, the vibration displacement characteristics of the optimized actuator were above 400 nm within the range of 0.1 to 1 kHz when a current of $1mA_{rms}$ was applied to the coil.

• 센서학회지
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• 제19권6호
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• pp.449-455
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• 2010

Implantable middle ear hearing devices(IMEHDs) have being actively studied to overcome the problems of conventional hearing aids. Vibration transducer, an output devices of IMEHDs, is attached on the ossicular chain and transmits mechanical vibration to cochlea. This approach allows us to hear more clear sound because mechanical vibration is effective to transfer high frequency acoustics, but occurs some problems such as fatigue accumulation to ossicular chian and reduction of vibration displacement caused by mass loading effect. Recently, many studies for the round window stimulation are announced, because it does not cause such problems. It have been studied by older transducers designed for attaching on ossicular chain. In this paper, we proposed a new electromagnetic transducer which consists of two magnets, three coils and a vibration membrane. The magnet assembly, magnet coupled in opposite direction, were placed in the center of three coils, and the optimum length of each coil generating maximum vibrational force was calculated by finite element analysis(FEA). The transducer was implemented as the calculated length of each coil, and measured vibration displacement. From the results, it is verified the vibration displacement can be improved by optimizing the length of coils.