ISEFT 마이크로센서용 샘플챔버 설계 및 4채널 전해질 분석기의 구현

배상곤,이호신,원철호,채승표,김창수,조병욱,손병기,김명남,조진호 ( Sang Kon Bae,Ho Shin Lee,Chul Ho Won,Seung Pyo Chae,Chang Soo Kim,Byung Wook Cho,Byung Ki Sohn,Myoung Nam Kim,Jin Ho Cho ) 한국센서학회 1997 센서학회지 Vol.6 No.4

In this paper, a sample chamber which provide easy replacement of ISFET sensor and consume only small sample volume for electrolyte analysis is designed and a 4-channel electrolyte analyzer employing 2-point calibration method is implemented. In addition, we proposed sample loading detection circuit for minimizing sample and calibration solutions and implemented it. Developed electrolyte analyzer consists of control system part and flow system part. For the effective control of the developed hardware, system software is developed as three individual routines ; measuring routine, calibration routine and washing routine.

광섬유 마이켈슨 간섭계형 교류 전류 센서

김창원,박동수,김명규,이정희,강신원,손병기 ( Chang Won Kim,Dong Su Park,Myung Gyoo Kim,Jung Hee Lee,Shin Won Kang,Byung Ki Sohn ) 한국센서학회 1995 센서학회지 Vol.4 No.2

A Michelson interferometric AC current sensor has been fabricated by using a single mode optical fiber and a cylindrical PZT tube of which a radial dimension varies with applied voltage. The signal processing scheme used in this work, measures the magnitude of AC current regardless of the frequency of the current. An AC current is measured by counting the number of interference fringe during half cycle of the AC current. he number of interference fringes varies linearly with the magnitude of the current and the error range is within 5% at the temperature range from -20 ℃ to 80 ℃.

광섬유 Fabry - Perot 간섭형 센서 제조를 위한 TiO2 반사막의 형성 및 그 특성

박동수,김명규,김창원,이정희,강신원,손병기 ( Dong Soo Park,Myung Gyoo Kim,Chang Won Kim,Jung Hee Lee ) 한국센서학회 1995 센서학회지 Vol.4 No.3

For the fabrication of high sensitive intrinsic fiber optic Fabry-Perot interferometeric sensor, the deposition conditions of TiO₂ thin film used to the internal mirrors of the sensor were investigated. The TiO₂ film deposited by RF magnetron sputter had higher refractive index (2.36∼2.98) and better stoiciometry (O/Ti = 2) than that deposited by e-beam evaporator. In the case of forming TiO₂ internal mirror by using fusion splicing technique, the TiO₂ reflection mirror deposited by RF magnetron sputter in the condition of 120W RF power showed high reflectance and excellent controllability of reflection power. The fabricated intrinsic fiber optic Fabry-Perot interferometer with two TiO₂ internal mirrors deposited under the condition showed very stable fringe patterns. It is. therefore, expected that the interferometer will be applicable to various high precision sensors.

광섬유를 이용한 전류센서의 개발(Ⅱ)

손병기,Taylor, H.F.,김창원 경북대학교 센서기술연구소 1993 연차보고서 Vol.1993 No.-

TiO_2가 코팅된 광섬유를 사용하여 광섬유 선로내에 두 개의 내부 반사막을 가지는 광섬유 Fabry-Perot 간섭계를 제조하였다. TiO_2 박막을 RF magnetron sputtering 법으로 증착하였다. RF 전력을 120∼140W 변화시킨 경우 TiO_2 박막의 굴절률 2.36에서 2.48까지 선형적인 증가를 보였으며 좋은 화학양론적 조성비(O/Ti=2)를 나타내었다. RF 전력이 120W인 증착조건에서 제조된 광섬유 Fabry-Perot 간섭계는 안정되고 깨끗한 fringe 패턴을 얻을 수 있었다. 그리고 PZT 위에 광섬유 Fabry-Perot 간섭계를 접착하여 전류센서를 제조하였으며 간단한 형태의 광섬유 전류센서용 신호처리회로를 설계하였다. 광섬유 전류센서는 0∼50Å의 동작영역에서 매우 선형적인 특성을 나타내었으며 전류센서 헤드 양단에 큰 저항체를 연결한 경우 감도는 증가하였지만 선형성은 좁게 나타났다. 변환된 광 신호를 처리하기 위해 zero-crossing 검출회로를 사용하였다. 전류센서의 특성개선을 위해 신호처리 회로에 50㎒ clock generator를 사용한 결과 1㎒의 clock generator를 사용했을 때보다 약 7배 정도 높은 감도를 나타내었다. Fiber optic Fabry-Perot interferometer which has two internal mirrors were fabricated by using TiO_2 film coated optical fiber and its Fabry-Perot interferometer chracteristics was investigated. TiO_2 film has been evaporated by RF magnetron sputtering method. Refractive index of TiO_2 film is linearly related from 2.36 to 2.48 increasing the RF power from 120W to 140W, where stoichiometric ratio(O/Ti=2) shown good. A stable and clear fringe pattern could be obtained through fiber optic Fabry-Perot interferometer which was fabricated in 120W RF power evaporation condition. And a FFPI(Fiber optic Fabry-Perot Interferometer) sensor is bonded on the PZT to make a current sensor. Then current sensor was fabricated and signal processing circuits for simple fiber optic current sensor was designed. The sensor exhibited very linear response in the current range of 0∼50 Å. And the higher resister is, conneted to the terminal of the current sensor, the better sensor resolution becomes and the power linear characteristics becomes, which indicate the good resolution sacrifice the good linear characteristics. Zero-crossing detection scheme is used to deal with the optical signal. For the purpose of improving the current sensor characteristics, by using 50㎒ clock in the signal processing circuit the resolution of the sensor was improved about seven times compare with by using 1㎒ clock.

광섬유 마이켈슨 간섭계형 교류 전압·전류센서

김창원,박동수,김명규,이정희,강신원,손병기 경북대학교 센서기술연구소 1994 센서技術學術大會論文集 Vol.5 No.1

A Michelson interferometric AC voltage/current sensor has been fabricated by using a single mode optical fiber and a cylindrical PZT of which a radial displacement varies according to applied voltage. A sensor head was fabricated by winding the sensing alai around a cylindrical PZT. An AC voltage, applied to the PZT, could be measured by number of interference fringe variation during one period of AC signal. A primary AC current also could be measured by pick-up coil. The pick-up coil produced a corresponding low level current which was transduced to voltage and applied to the PZT. The measured fringe variation was linearly dependent on the amplitude of the applied voltage but had no relation with frequency. Linear response was obtained in the voltage range of 0~100V.

광섬유를 이용한 전류센서의 개발(Ⅲ)

손병기,이정희,김창원 경북대학교 센서기술연구소 1994 연차보고서 Vol.1994 No.-

Fabry-Perot 간섭계 형성기술 및 광 신호처리기술을 기초로 하여, 독자적인 역량으로 광섬유 전류센서를 개발하였다. 또한 미소 압력변화를 감지할 수 있는 고감도 압력센서에 응용하였다. 압전체인 PZT를 이용한 Fabry-Perot 간섭형 전류센서를 제조하였으며, 제조된 전류센서는 20 A까지 선형적인 응답특성을 나타내었다. 또한 전류센서의 특성개선을 위해 주파수가 큰 클럭을 사용하여 감도를 향상시켰다. 광섬유 전류센서시스템 제작에는 Zero-crossing 기법으로 PC와 연결된 간단한 전류센서용 신호처리회로를 제작하였다. 이 시스템에서는 100여개의 데이타를 받아들여 처리할 수 있는 프로그램을 개발하여 전류센서의 신뢰도를 높였다. 신호처리가 손쉬운 optical isolator와 경제적인 면에서 매운 유리한 time division multiplexing법을 이용한 다점측정식 전류센서를 설계하였다. Micro-cavity형 간섭계의 제조 및 특성조사에는 Si_3N_4/SiO_2/Si_3N_4 유전체 다이아프레임 박막을 가지는 광섬유 Fabry-Perot 간섭계를 제조하였으며 압력센서에 응용하였다. The development of fiber optic current sensor was carried out soley at KNU on the basis of the research on the formation technology of Fabry-Perot interferometer and optical system for the third year of the project. Additionally, micro-cavity type was fabricated. The works achieved in this project are expected to contribute to development of the domestic fiber optic sensor technology. The current sensor of the Fabry-Perot interferometric type using PZT plate show good lineality in the current range of 0∼20A. Besides the characteristics of the current sensor were improved by usage of high frequency clock, and fabricated multiple current sensor using the optical isolator and time division multiplexing. In the manufacture of the fiber optic current sensor system, designed of the fiber optic current sensor system with the connection of a new and simple signal processing circuit containing a comparator and counter to PC interface card. The micro-cavity type interferometer using IC process technique have been studied. The fiber optic interferometer with stress-free NON dielectric diaphragm thin film was applied to pressure sensor.

Micro-cavity형 광섬유 Fabry-Perot 간섭계의 형성 및 고감도 압력센서에의 응용

김명규,박동수,김창원,김진섭,이정희,손병기 경북대학교 센서기술연구소 1994 센서技術學術大會論文集 Vol.5 No.1

Because micro-cavity type optical fiber Fabry-Perot interferometric pressure sensor itself play a signal processing role, it has electrical safty and is immune to EMI(electro-magnetic interference). And it also has high sensitivity in the measured range and low sensitivity dependence on the thickness of diaphragm. Therefore it has many advantages, so it will be applicable to accelerate sensor, flow sensor, and microphone, etc.. In this paper, using silicon anisotropic etching technique and fiber optic sensing technique, micro-cavity type optical fiber Fabry-Perot interferometer was formed and a highly sensitive pressure sensor was fabricated. The fabricated micro-cavity type optical fiber Fabry -Perot interferometric pressure sensor showed repeatedly good output characteristics.

Febry-Perot 간섭계를 이용한 광섬유 온도센서의 제조

김명규,박동수,김창원,예윤해,최시영,김기완,손병기 경북대학교 센서기술연구소 1992 센서技術學術大會論文集 Vol.3 No.1

광섬유를 이용한 고감도 압력센서의 개발

김창원,권대혁,김진섭,이정희,손병기 경북대학교 센서기술연구소 1995 연차보고서 Vol.1995 No.-

KOH 수용액을 이용하여 실리콘 식각공정기술을 확립하였으며, 이를 이용하여 실리콘 기판 위에 스트레스 균형이 이루어진 150 ㎚-Si_3N_4/300 ㎚-SiO_2/150 ㎚-Si_3N_4 두께를 가지는 구조의 평탄한 3층 유전체 멤브레인을 제작하였다. 본 실험에서 사용되는 파장인 1.3 ㎛ 근방에서 다이아프레임의 광투과도는 약 50 %로 광반사막으로 사용이 불가능하였다. 따라서, 다이아프레임 뒷면에 약 1000 Å의 금을 증착하여 N/O/N/Au박막의 광투과도를 수 %정도로 감소시킴으로써, 센서의 광반사막으로 사용할 수 있었다. source fiber를 단일모드로 했을 때 다이아프레임의 크기에 따라 감도는 각각 0.52㎻/torr(3×3 ㎟), 0.65 ㎻/torr(4×4 ㎟), 0.77 ㎻/torr(5×5 ㎟)였다. 광손실을 최소화하기 위해 광전송용 다모드 광섬유를 사용하였을 때는, 2×2 ㎟의 다이아프레임의 크기에 대해 0∼800 torr의 넓은 측정범위에서 거의 선형적인 압력특성을 나타내었다. Using KOH solution, silicon etching technology has been established and stress-balanced flat 600 ㎚ thick triple dielectric membrane(150 ㎚-Si_3N_4/300 ㎚-SiO_2/150 ㎚-Si_3N_4) on silicon substrate has been fabricated. At the wavelength of the sensor light source near 1.3 ㎛, the optical transmittance of the diaphragm was about 50 %, it was impossible to be used as a reflecting film. To decrease to a few percents, the back-side of the diaphragm was deposited 1,000 Å thick gold layer, which is sufficient enough to be used as a light reflection layer of the sensor. When was used 8/126 ㎛ single-mode fiber, the respective sensitivities for diaphragm size were 0.52 ㎻/torr(3×3 ㎟), 0.65 ㎻/torr(4×4 ㎟), 0.77 ㎻/torr(5×5 ㎟). When was used 62/126 ㎛ multi-mode fiber for the light transmission to minimize optical loss, the pressure characteristics was showed almost linearly curve in a wide pressure range, 0 torr∼800 torr, for the 2×2 ㎟ diaphragm in dimensions.

광섬유 Fabry-Perot 간섭형 온도센서

김창원,손병기,박동수,김명규 경북대학교 전자기술연구소 1993 電子技術硏究誌 Vol.14 No.1

A fiber optic Fabry-Perot interferometric temperature sensor, compared with conventional temperature sensor, has any advantages, such as rapid response, high sensitivity in the wide range, point measurement and multi-point detection. The fiber optic Fabry-Perot interferometric temperature sensor which has two internal mirrors was fabricated using Ties coated optical fibers. The fabricated temperature sensor showed relatively linear and stable response in the temperature range of 50℃∼730℃. And the phase shift was 0.942 radians/℃ which was good agreement with theoretic value (1.0367 radians/℃) below 300℃.