위식도 역류 실시간 모니터링 마이크로 와이어 pH 전극 개발

김응보,이규진,소상균,정연호,박정호,김남희 대한의용생체공학회 2017 의공학회지 Vol.38 No.6

This paper presents an implantable pH measurement electrode for wireless gastroesophageal reflux measurement. Usually, gastroesophageal reflux is diagnosed by a catheter-type wire connection between the esophagus and the diagnostic device which brings many side effects such as restriction of daily living, pain, and discomfort in the nasal cavity and pharynx of patients. In order to solve these issues, researchers have been studied a wireless measurement method and a micro-sized pH electrode for human body insertion is necessary. Commercial glass packaged pH meter is formed by a sensing and a reference electrodes in a KCl solution. However, if the glass meter is inserted into the human body, there are risks of leakage of the solution, breakage of the glass package, injury of the body elements. Therefore, the solution should be solidified on the micro-sized noble metal wire which has a characteristic of biocompatible. After solidified wire fabrication, the designed meter was tested for feasibility of measurement and the result was well agreed with pH values of commercial pH meter. Potentials in pH 1 to 12 solution was measured to obtain the sensitivity of the sensor with linearity. And we have designed a simulation of gastroesophageal reflux with symptom frequency, interval, and duration time in pH 2 solution. The proposed sensor has capable to get the same potential for 24 measurements in 3 days, and it has sensed same pH values of 2 for one hour with every 10 minutes. Furthermore, the sensor was survived for 48 hours with reasonable potentials in the acid solution.

Implantable 심장박동기를 위한 밀폐형 Quartz Packaging에 대한 연구

김응보(Eung-Bo Kim),박재순(Jae-Soon Park),정연호(Yeun-Ho Joung) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.11

광가이드 필름을 이용한 베젤리스 디지털 사이니지 구현에 관한 연구

박재순,김응보,강영환,최원석,정연호 한국위성정보통신학회 2016 한국위성정보통신학회논문지 Vol.11 No.1

본 논문은 빛을 일정한 방향으로 전달하는 광가이드 특성을 이용하여 디지털 사이니지 베젤에서의 광학적 불연속성을 개선하고자한다. 광학적 성능이 우수한 Polycarbonate에 Light guide film을 부착, 필름 내부에 존재하는 마이크로 사이즈의 구조에 의한 빛의굴절, 반사, 산란의 효과를 발생하였다. 아크(arc) 모양의 polycarbonate 광가이드 필름을 각기 다른 색의 LED source (적색, 녹색)에기계적으로 밀착하여 광학적 전달효과를 관찰하였다. 아크 형태의 광가이드 필름에 빛의 반사 및 산란이 발생하여 녹색과 붉은색의혼합색인 주황색이 발생하는 것을 확인하였다. 이는 일반적으로 베젤이 존재하는 멀티 디지털 사이니지 시스템의 약점인 디스플레이의 광학적 불연속성을 해결할 수 있을 것으로 판단된다. This paper present a method which resolves an optical discontinuity in bezel of digital signage using light guide film. On a polycarbonate film, a light guide film is bonded to produce refraction, reflection, diffraction of light. Arc shaped light guide film is assembled on the top LED light sources (red and green) to see light propagation through the film. When the two light sources (red and green) are mechanically attached at the end of the film, optical convergence brings new colors which have light wavelength between red and green. This result indicates that the light waveguide method could solve the light discontinuity on bezel of the digital signage system.

Quatrz 웨이퍼의 직접접합과 극초단 레이저 가공을 이용한 체내 이식형 혈압센서 개발

김성일,김응보,소상균,최지연,정연호,Kim, Sung-Il,Kim, Eung-Bo,So, Sang-kyun,Choi, Jiyeon,Joung, Yeun-Ho 대한의용생체공학회 2016 의공학회지 Vol.37 No.5

In this paper we present an implantable pressure sensor to measure real-time blood pressure by monitoring mechanical movement of artery. Sensor is composed of inductors (L) and capacitors (C) which are formed by microfabrication and direct bonding on two biocompatible substrates (quartz). When electrical potential is applied to the sensor, the inductors and capacitors generates a LC resonance circuit and produce characteristic resonant frequencies. Real-time variation of the resonant frequency is monitored by an external measurement system using inductive coupling. Structural and electrical simulation was performed by Computer Aided Engineering (CAE) programs, ANSYS and HFSS, to optimize geometry of sensor. Ultrafast laser (femto-second) cutting and MEMS process were executed as sensor fabrication methods with consideration of brittleness of the substrate and small radial artery size. After whole fabrication processes, we got sensors of $3mm{\times}15mm{\times}0.5mm$. Resonant frequency of the sensor was around 90 MHz at atmosphere (760 mmHg), and the sensor has good linearity without any hysteresis. Longterm (5 years) stability of the sensor was verified by thermal acceleration testing with Arrhenius model. Moreover, in-vitro cytotoxicity test was done to show biocompatiblity of the sensor and validation of real-time blood pressure measurement was verified with animal test by implant of the sensor. By integration with development of external interrogation system, the proposed sensor system will be a promising method to measure real-time blood pressure.

프리즘 구조의 집광효과를 이용한 이산형 LED 패널의 광학적 연속성 구현에 관한 연구

조성환,김응보,최원석,정연호 한국위성정보통신학회 2017 한국위성정보통신학회논문지 Vol.12 No.2

본 논문은 프리즘 구조물의 집광효과를 이용하여 옥외용 사이니지 이산형 LED 패널의 광학적 불연속성을 개선할 수 있는 방법적접근에 관한 것이다. 광투과성이 우수한 Polycarbonate에 MEMS(Microelectromechanical systems) 공정 및 극초단파(Femto-second) 레이저를 이용하여 프리즘 형태를 패터닝을 하였다. 패터닝된 polycarbonate는 light guide film의 역할을 하여 서로다른 디스플레이 패널에서 발생하는 빛을 프리즘 구조에 의해 한 곳으로 모이게 함을 확인하였다. Polycarbonate와 디스플레이 패널의 간격에 따라 디스플레이 패널간의 거리를 조절할 수 있었으며 한 곳으로 모인 빛은 마치 두 디스플레이 패널이 연결된 것과 같은효과를 나타내었다. 이는 아웃도어 사이니지용 디스플레이 패널에서 발생하는 문제점인 광학적 불연속성을 개선할 수 있을 것으로보인다. In this paper, we introduce a method of light focusing effect using prism structure to solve optical discontinuity of conventional external signage LED panels. The prims structures were patterned on a transparent polycarbonate substrate with MEMS and femto-second laser process. We have confirmed that the patterned prism structures on the substrate made artificial LED lights on empty space between the panels by light guide effect of the structure. The artificial light’s lateral positions were controlled by thickness of polycarbonate substrate. This cost effective prim patterned transparent film can be utilized on digital signage LED panels to achieve good optical communication.

약물 투여에 따른 기니피그 대장 운동 측정을 위한 압력센서 개발

박재순,박정호,김응보,조성환,장수정,정연호,Park, Jae-Soon,Park, Jung-Ho,Kim, Eung-Bo,Cho, Sung-Hwan,Jang, Su-Jeong,Joung, Yeun-Ho 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.1

In this paper, in order to quantify the peristalsis occurrence in a guinea pig's large intestine, a miniaturized air-gap capacitive pressure sensor was fabricated through micro-electro-mechanical system (MEMS). The proposed pressure sensor is a two-layered biocompatible polyimide substrate consisting of an air-gap capacitive plates between the substrates. The proposed pressure sensor was designed with a careful consideration of the structure and motility mechanism of the guinea pig's large intestine. Artificial pellets were mounted on a prototype pressure sensor to provide some redundancies in the form of size and shape of the guinea pig feces. Capacitance of a prototype sensor was recorded to be 2.5 ~ 3 pF. This capacitance value was later converted to count value using a lab fabricated data conversion system. Sensitivity of the pressure sensor was recorded to be below 1 mmHg per atmospheric pressure. During in vivo testing, artificial peristalsis caused by drug injection was measured by inserting the prototype pressure sensor into the guinea pig's large intestine and pressure data obtained due to artificial peristalsis was graphed using a labview program. The proposed pressure sensor could measure the pressure changes in the proximal, medial, and distal parts of the large intestine. The results of the experiment confirmed that pressure changes of guinea pig's large intestine was proportional to the degree of drug injection.

생체 이식형 의료기기의 패키징을 위한 완전 밀폐 방법에 관한 연구

박재순,김성일,김응보,강영환,조성환,정연호 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.7

In this paper, we introduce a biocompatible packaging system for implantable medical device which has hermetic sealing to get perfect physical and chemical isolation between electronic medical system and human body including tissue, body fluids, and etc. The hermetic packaging include a electronic MEMS pressure sensor, power charging system, and bluetooth communication system to wirelessly measure variation of capacitance. The packaging was obtained by Quartz direct bonding and CO2 laser welding with size of width 6 cm × length 10 cm × height 3 cm. Hermetic sealing of the packaged system was tested by changing of pressure from atmosphere to 900 mmHg in hermetic chamber by precision pressure controller. We found that the packaged system had same count or capacitance values with sensor1 - 25500, sensor2 - 26000, sensor3 – 20800 at atmosphere and 900 mmHg for 5 hours. This result shows that the packaging method has perfect hermetic sealing in environment of human body pressure. 본 논문에서는 인체 삽입형 의료기기의 유해성분과 생체 조직의 물리적, 화학적 완전분리를 위해 무선통신 및 무선충전이 용이하며, 인체 조직과 접촉해도 물리적·화학적 반응이 발생하지 않는 생체 적합성 소재인 quartz를 이용한 의료기기 패키징을 개발에 대한 것이다. 패키징의 밀폐성을 평가하기 위해 패키징 내부에 micro-electro-mechanical system (MEMS) 공정을 이용하여 제작된 압력센서와 외부 신호 측정 리더기가 무선으로 통신 가능한 압력센서 시스템을 내장하여 외부 압력변화에 따른 패키징 내부의 압력변화를 측정하였다. 패키징은 압력측정 시스템의 크기를 고려하여 폭 6 cm × 길이 10 cm × 높이 3 cm로 제작되었으며, CO2 레이저 가공을 통해 최종 완성되었다. 제작된 패키징의 밀폐성 평가를 위해 미세 압력조절기와 압력챔버로 구성된 성능평가 시스템을 자체적으로 구성하였으며, 실험은 인체 내에서 발생할 수 있는 압력을 고려하여 대기압과 900 mmHg의 높은 공기압의 환경에서 실시되었다. 그 결과 패키징은 대기압과 900 mmHg의 공기압에서 모두 동일한 count 값 (sensor1 - 25500, sensor2 - 26000, sensor3 – 20800)을 나타냈으며, 이를 통해 패키징의 내부 압력환경이 인체에서 외부 압력변화에 영향을 받지 않는 완전밀폐 되었음을 확인할 수 있었다.

LPATS-Ⅲ의 오차검토 및 한반도 낙뢰발생빈도 분석결과

우정욱(J.W. Woo),심응보(E.B. Shim),권동진(D.J. Kwon),최영민(Y.M. Choi),이성진(S.J. Lee),김기운(K.W. Kim),이복희(B.H. Lee) 대한전기학회 2002 대한전기학회 학술대회 논문집 Vol.2002 No.7

낙뢰위치표정시스템의 낙뢰 DB를 이용한 한반도 뇌격 특이특성 분석

우정욱(J.W.Woo),곽주식(J.S.Kwak),심응보(E.B.Shim),이건웅(G.W.Lee),김기운(K.W.Kim),김병식(B.S.Kim) 대한전기학회 2001 대한전기학회 학술대회 논문집 Vol.2001 No.7

낙뢰정보 실시간 통계분석시스템 개발

곽주식(J.S. Kwak),우정욱(J.W. Woo),심응보(E.B. Shim),김기운(K.W. Kim),김용수(Y.S. Kim),이성진(S.J. Lee),이건웅(G.W. Lee) 대한전기학회 2003 대한전기학회 학술대회 논문집 Vol.2003 No.7