• 한국생산제조학회지
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• 제23권6호
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• pp.539-546
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• 2014

This paper describes an ultra-precision electronic clinometer, which is based on the capacitive-based fluid type, for detection of small inclination angles. The main parts of the clinometer low-noise electronics are two capacitance measurement circuits for converting the capacitances of the capacitors of the clinometer into voltages, and a differential amplifier for obtaining the difference of the capacitances, which is proportional to the input inclination angle. A 16 bit analog to digital (AD) converter is also embedded into the same circuit board, whose output is sent to a PC via RS-232C, for achieving a small noise level down to tens of ${\mu}v$. A compensation method, which is referred to as the delay time method for shortening the stabilization time of the sensor was also discussed. Experimental results have shown the possibility of achieving a measurement resolution of $0.0001^{\circ}$ as well as the quick measurement with the delay time method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.875-877
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• 2011

본 논문에서는 개선된 charge pump 회로를 이용하여 구성한 터치스크린 패널 드라이버를 소개한다. 터치 패널 드라이버는 크게 터치를 감지하는 아날로그 센싱 부분과 감지된 신호를 처리하는 디지털 신호 처리 부분으로 이루어진다. 제안된 터치스크린 드라이버의 동작을 확인하기 위하여 혼성 모드로 회로를 구성하고 Cadence Spectre를 이용하여 그 동작을 검증하였다. 디지털 회로 부분은 Verilog-A 모델링하여 아날로그 부분과의 인터페이스가 가능하게 하여, 그 동작을 검증함으로써 동작의 신뢰성을 확보하였고 시뮬레이션 시간을 줄일 수 있었다. 시뮬레이션 결과 ADC가 없는 간단한 구조의 디지털 신호 변환으로 터치 패널 드라이버의 안정적인 동작을 확인하였다.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2871-2876
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• 2022

The sensitivity of polymer-based capacitive relative humidity (RH) sensors after irradiation with neutrons, electrons and protons was measured. Degradation consists of the decreasing of the upper RH limit that can be measured. At the same time, low RH-level sensitivity is almost stable. After 30 krad of absorption dose, RH cut off is equal to 85% of max value, after 60 krad-40%. Degradation reduces after annealing which indicates high radiation sensitivity of the internal circuit in comparison to RH-sensing polymer film.

• 대한전자공학회논문지SD
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• 제42권11호
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• pp.1-8
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• 2005

본 논문은 MEMS (Micro-Mechanical-Electronic System) 기술을 이용한 온도, 압력, 습도 복합 센서의 설계와 제작, 그리고 평가에 관한 것이다. 이러한 MEMS 복합 센서는 휴대 전화나 PDA와 같이 가정용 제품에 사용되어 환경을 모니터링하는 건강 측정용 센서로서 사용될 것이다. 이 연구의 범위는 이러한 개별 센서의 연구 및 모든 센서를 하나의 실리콘 웨이퍼 상에서 집적할 수 있는 구조에 관한 연구, 그리고 복합 센서를 MEMS 공정에서 제작할 수 있는 공정 호환성에 대한 연구와 얻어진 센서 prototype의 측정, 평가로 이루어져 있다. 이 연구에서 우리는 온도와 압력 센서의 경우에는 선형성과 이력특성이 $1\%FS$안에 들어오는 특성을 얻었으며 단지 습도 센서의 경우에는 $5\%FS$에 해당하는 선형성과 이력 특성을 얻었다. 다만 원리적으로 습도 센서의 동작 특성은 비선형적이며 우리가 3차로 근사화할 경우에 보다 낳은 결과를 얻을 것을 기대할 수 있다. 이러한 특성을 더욱 개선하기 위한 것은 추후의 연구 영역이 될 것이다.

• 센서학회지
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• 제17권3호
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• pp.195-202
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• 2008

A biosensor based on the measurement of capacitance changes has been designed and fabricated for simple and realtime detection of bacteria. Compared to an impedance measurement technique, the capacitance measurement can make additional measurement circuits simpler, which improves a compatability for integration between the sensor and circuit. The fabricated sensor was characterized by detecting Escherichia coli(E. coli). The capacitance changes measured by the sensor were proportional to E. coli cell density, and the proposed sensor could detect $1{\times}10^6$ cfu/ml E. coli at least. The real-time detection was verified by measuring the capacitance every 20 minutes. After 7 hours of E. coli growth experiment, the capacitance of the sensor in the micro volume well with $4.5{\times}10^5$ cfu/ml of initial E. coli density increased by 20 pF, and that in another wells with $1.5{\times}10^6$ cfu/ml and $8.5{\times}10^7$ cfu/ml initial E. coli density increased by 56 pF and 71 pF, respectively. The proposed sensor has a possibility of the real-time detection for bacterial growth, and can detect E. coli cells with $1.8{\times}10^5$ cfu in nutrient broth in 5 hours.

• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.412-417
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• 2022

Capacitive-type humidity sensors with a high sensitivity and fast response/recovery times have attracted a great attention in non-contact respiration biological signal monitoring applications. However, complicated fabrication processes involving high-temperature heat treatment for the hygroscopic film is essential in the conventional ceramic-based humidity sensors. In this study, a non-toxic ceramic/metal halide (BaTiO₃(BT)/NaCl) humidity sensor was prepared at room temperature using a solvent-free aerosol deposition process (AD) without any additional process. Currently prepared BT/NaCl humidity sensor shows an excellent sensitivity (245 pF/RH%) and superior response/recovery times (3s/4s) due to the NaCl ionization effect resulting in an immense interfacial polarization. Furthermore, the non-contact respiration signal variation using the BT/NaCl sensor was determined to be over 700% by maintaining the distance of 20 cm between the individual and the sensor. Through the AD-fabricated sensor in this study, we expect to develop a non-contact biological signal monitoring system that can be applied to various fields such as respiratory disease detection and management, infant respiratory signal observation, and touchless skin moisture sensing button.

• 전자공학회논문지D
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• 제35D권9호
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• pp.77-86
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• 1998

본 논문에서는 정전용량형 센서 칩과 CMOS 인터페이스 칩으로 구성된 투 칩 집적화 습도 센서를 개발하였다. (100) 실리콘 기판위에 폴리이미드 박막을 이용해서 제작된 습도 센서 칩은 넓은 습도 및 온도 범위에 걸쳐 우수한 직선성(0.72%FS), 낮은 히스테리시스(<3%), 작은 온도계수(-0.0285∼-0.0542 pF/K)를 나타내었다. 40℃/90%RH에서 9주동안 방치한 후 측정된 정전용량은 약 2∼3% 변하였다. 신호처리 회로는 1.2-㎛, one poly double metal CMOS 공정으로 제작하였다. 측정된 센서 출력 전압은 상대습도에 비례해서 변하였으며, 이론치와 잘 일치하였다.

• 센서학회지
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• 제19권1호
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• pp.25-30
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• 2010

This paper presents a low noise CMOS regulator for a low power capacitive sensor interface in a $0.5{\mu}m$ CMOS standard technology. Proposed LDO regulator circuit consist of a voltage reference block, an error amplifier and a new buffer between error amplifier and pass transistor for a good output stability. Conventional source follower buffer structure is simple, but has a narrow output swing and a low S/N ratio. In this paper, we use a 2-stage wide band OTA instead of source follower structure for a buffer. From SPICE simulation results, we got 0.8 % line regulation and 0.18 % load regulation.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.130-136
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• 2004

Presence of water in the lubricating oils could be one of the first indicators of potentially expensive and possibly catastrophic failure of the machine as it may cause displace the oil films to prevent the lubrication function of the oil or chemically react with many oil additives resulting in the oil degradation. In order to detect water content quantitatively in lubricating oils many methods and sensors has been developed. Among these, capacitive sensors including sensitive layer, whose dielectric factor changes according to the water content absorbed in the layer, are proposed mainly in the market. But these sensors are not sensitive to a high water content. Besides, the absorbing layer soils in time. In this work, an evaporation of water moisture from oil into air volume above lubricant surface and condensation of water vapor at a cooling surface was used to measure water content quantitatively in an lubricating oil. Laboratory test results of a prototype sensor were presented. Test results showed that the proposed method could be avaliable to measure a low levels of oil moisture.

• 전기학회논문지P
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• 제57권3호
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• pp.265-269
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• 2008

Output voltage value of AC high voltage source has usually been obtained by measuring the low arm voltage of high voltage divider or the secondary voltage of high voltage transformer. In this study, we have fabricated the AC 400 kV high voltage divider using high voltage electrode and electric field measurement sensor. The dividing ratio of the fabricated 400 kV high voltage divider was evaluated using reference 400 kV capacitive divider. The dividing ratio of 400 kV high voltage divider is found to be 12,322 and has the good linearity within 0.63 % against AC high voltage up to 400 kV. Therefore, the developed 400 kV high voltage divider could evaluate 400 kV high voltage supply and voltage divider used in industry.