• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.155-161
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• 2016

This paper proposes a novel fabrication method for a capacitive type micro-accelerometer with uniform nano-gap using photo-assisted electro-chemical etching. The sensitivity of the accelerometer should be improved while the electrodes between the inertial mass and the sensing comb should be narrowed. In this paper the nano-gap trench structure is fabricated using the photo-assisted electrochemical etching method. The sensor was designed and analysed using ANSYS simulator. The characteristics of the etching were observed according to the dc bias, the light intensity, the composition of the solution, the temperature of the solution, and the pattern pitch variation. The optimum etching conditions were dc bias of 2V, Blue LED of 20mA, 49wt% HF:DMF:D.I.Water=1:20:10, the pattern pitch of $20{\mu}m$. Uniform trench structure with width of 344nm and depth of $11.627{\mu}m$ are formed using the optimum condition.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.6
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• pp.335-340
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• 2000

We report the results of a preliminary investigation on capacitive humidity sensors using iodine-doped polyphenylacetylene(PPA) thin films. PPA was prepared from phenylacetylene(PA), chemically doped with iodine, and characterized by DSC, $^1H$-NMR and FTIR spectra. The iodine-doped PPA sensors showed a sensitivity of 0.20pF/%RH, a linearity of 3.8%FS, a negligible hysteresis, and a low temperature coefficients of $0.043~0.067pF/^{\circ}C$ over a wide range of relative humidity. These results are expected to open up the possibility of iodine-doped PPA thin films as relative humidity sensors.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1511-1513
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• 2003

본 논문에서는 polyimide를 감습물질로 한 정전용량형 정밀습도센서를 개발하여 실용화한 결과를 보고한다. 유리기판에 제작된 습도센서는 상대습도 11%RH${\sim}$96%RH 범위에서 다음과 같은 특성을 나타내었다. 감도; 0.5689 pF/%RH, 비선형성; 1.5%RH 미만, 히스테리시스; 약 1.5%RH, 감도특성의 온도 의존성; 0.08pF/$^{\circ}C$, 주파수 특성; 10, 100kHz에서 직선적.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1848-1850
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• 2004

변압기에 사용되는 절연유의 열화정도를 변압기의 운전정지 없이 실시간으로 측정할 수 있는 전기용량을 이용한 센서를 개발하였다. 개발된 전기용량형 센서는 3-전극형의 구조와 변압기에 센서의 외부상자가 접지 될 때 2중의 정전차폐가 되도록 하여 외부로부터의 잡음에 영향을 받지 않도록 하였다. 또한 변압기에서 절연유의 온도변화에 따른 유전율 변화를 보상하기위하여 기준용 센서와 측정용 센서를 한개의 변압기에 장착함으로 온도보상이 되도록 하였다. 제작된 센서는 변압기에서 절연유의 사용기간에 따른 유전율의 변화를 정확히 측정하였으며, 절연유의 체적저항의 변화도 감지 할 수가 있다. 따라서 센서에서 출력되는 신호를 phase sensitive detector를 사용하여 유전율의 변화로 혹은 체적저항의 변화로도 나타내 보일 수가 있다.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.548-553
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• 2000

A new design of cylindrical capacitive sensor(CCS) for the displacement measurement of precision active magnetic bearing(AMB) spindle is presented in this paper. This research is motivated by the problem that existing 4-segment CCS is still sensitive to the $3^{rd}$ harmonic component of the geometric errors of a rotor. The procedure of designing new CCS starts from the modeling and error analysis of CCS. The angular size of CCS is set up as a design parameter, and new 8-segment CCS is introduced to possess an arbitrary angular size. The optimum geometry of CCS to minimize the effect of geometric errors is determined through minimum norm approach. Experimental results with test rotors have confirmed the improvement in geometric error suppression.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.573-577
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• 2007

터치 센서를 이용한 휴대단말용 인터페이스가 다양하게 개발되면서 차세대 인터랙션 수단으로서 많은 주목을 받고 있지만, 버튼 인터페이스에 비해 오동작에 취약하고 터치 인터페이스만의 차별성을 확보하지 못하고 있는 실정이다. 본 논문에서는 터치 드래그 동작을 주요 인터랙션 수단으로 활용한 모바일 기기용 사용자 인터페이스를 개발하여 오동작을 최소화하고 사용자가 조작할 때 즐거움을 줄 수 있는 UI 요소로 활용할 수 있도록 하였다. 본 논문에서 개발한 터치 인터페이스는 기기의 내부/외부 방향의 스크롤 동작을 각각 drag-in/drag-out 동작으로 칭하고 이러한 드래그 동작을 응용 프로그램의 실행과 종료에 할당하였으며 터치 센서를 따라 움직이는 스크를 동작은 기존과 동일하게 일반적인 스크롤 행위를 지시하는데 적용하였다. 제안한 인터랙션 방법은 터치 센서의 형태에 따라 크게 두 가지 방식으로 구현하였다. 첫 번째 방법은 기기 스크린 외곽에 터치 센서를 이열(二列) 배치하여, 터치스크린을 사용하지 않고도 스크린 주변의 터치 센서를 활용한 drag-in/out 동작의 감지가 가능하도록 하였다. 두 번째 구현 방법은 정전용량형 터치 센서 IC를 활용해 터치 스크린 기능과 함께 스크린 주변의 기기 케이스의 일부까지도 사용자의 접촉을 감지할 수 있도록 하였다. 기존 저항 방식 터치 스크린과 달리 본 논문에서 활용한 방식은 스크린과 케이스에서 동시에 터치를 감지할 수 있으며, 다접점 감지 알고리즘의 개발로 두 개의 손가락을 이용한 다양한 터치 인터랙션으로 활용할 수 있다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.225-229
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• 2011

In this study, capacitive type pressure sensors based on low temperature co-fired ceramics (LTCC) technology for environmental monitoring were demonstrated. The LTCC is one of promising technology than is based one since it has many advantages (e.g., low cost production, high manufacturing yields and easy realizing 3D structure etc.) for sensor application. Especially, it has good mechanical and chemical properties for robust environmental application. The 3D LTCC diaphragm with thickness of 400 ${\mu}m$ were fabricated by laminating 4 green sheets using commercial powder (NEG, MLS 22C). To evaluate the sensing properties of the different cavity areas, two types of diaphragm which had different cavity areas with 25, 49 $mm^2$ respectively, were fabricated. To realize capacitive type pressure sensor, the Au top electrode was fabricated using thermal evaporator and the bottome electrode was compressed using aluminium foil. The sensing properties of the fabricated sensors showed linear characteristic under different pressure (0~30 psi) using pressure measurement system.

• Journal of Aerospace System Engineering
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• v.12 no.6
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• pp.17-22
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• 2018

The amount of fuel, which affects aircraft endurance, needs to be measured accurately. This paper deals with the implementation of a fuel quantity measurement system that consists of capacitive fuel sensor, DAQ board, and Labview software. The main circuit of the implemented system for measuring fuel quantity is simulated with Pspice to identify parameters, which are related to the change of fuel quantity. After simulation, we established that Vrms changes with the variation of fuel amount. The Vrms, which is the output of fuel sensor, is transmitted to the Labview software via the DAQ board of the implemented fuel quantity measurement system. The fuel quantity is also calculated using this software. The present simulation results indicated that the accuracy of the implemented fuel quantity measurement system improved with the filter application.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.387-393
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• 2004

General purpose of cylindrical capacitive displacement sensor(CCS) is measuring run-out motion and deflection of rotor. If CCS has narrow sensing range, its sensitivity coefficients must be calibrated precisely. And x, y component of CCS output can be coupled. In this research, CCS calibration procedure is automated with automatic calibration program and PC-controlled stage. And, coupled-terms of CCS signals were removed and the errors between measured position and mapped CCS signal were reduced obviously by sensitivity matrix that linearly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.655-662
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• 2007

This paper presents a disk-type capacitive sensor for simultaneous measurement of five-dimensional motions of a target. The sensor can be manufactured with a printed circuit board (PCB) such that the sensor can be integrated with its electronics in a single PCB board, whereby the manufacturing costs is considerably reduced. The sensor is optimally designed through an error analysis of possible mechanical errors. Furthermore, the sensor can correct the horizontal motion measurement errors due to the sensor installation tilting error. A proto-type PCB sensor, electronics and a test rig were built, and the effectiveness of the developed sensor was proved through experiments.