은나노와이어·전도성고분자 하이브리드 필름을 이용한 유연 투명 정전용량형 압력 센서의 특성

안영석,김원효,오해관,박광범,김건년,좌성훈,Ahn, Young Seok,Kim, Wonhyo,Oh, Haekwan,Park, Kwangbum,Kim, Kunnyun,Choa, Sung-Hoon 한국마이크로전자및패키징학회 2016 마이크로전자 및 패키징학회지 Vol.23 No.3

본 연구에서는 유연하고 투명한 특성을 지닌 유연 투명 정전용량형 압력 센서를 제안하여 기존의 X, Y 좌표 위치 인식이 가능할 뿐만 아니라 3차원 인식이 가능한 터치스크린을 제작하였다. 유연 투명 정전용량형 압력 센서는 상부 기판, 압력 감지층, 하부 기판의 3 중 구조로 구성되어 있다. 은나노와이어 전도성고분자 하이브리드 필름이 상부 및 하부 기판으로 사용되었다. 유연 투명 정전용량형 압력 센서의 터치 면적은 5인치이며, 전기적 신호를 인가하기 위한 11개의 driving line과 정전용량의 변화를 감지하기 위한 19개의 sensing line으로 구성되었다. 은나노와이어 전도성고분자 하이브리드 필름 및 유연 투명 정전용량형 압력 센서의 전기적, 광학적 특성을 평가하였다. 또한 기계적 유연성을 평가하기 위하여 굽힘 시험을 수행하였다. 제작된 은나노와이어 전도성고분자 하이브리드 필름은 평균 투과율 91.1%, 평균 탁도 1.35%로서 매우 우수한 광학 특성을 나타내었고, 평균 면저항은 $44.1{\Omega}/square$이었다. 굽힘 시험 결과 은나노와이어 전도성고분자 필름은 곡률 반경 3 mm까지 저항의 변화가 거의 없어 매우 우수한 유연성을 갖고 있음을 알 수 있었다. 또한 200,000회의 반복 굽힘 피로 시험 결과, 저항의 증가는 매우 미미하여, 유연 내구성이 매우 우수함을 알 수 있었다. 유연 투명 정전용량형 압력 센서의 평균 투과율은 84.1%, 탁도는 3.56%이었다. 또한, 직경 2 mm의 팁으로 눌렀을 경우, 누르는 압력에 따라 센서가 잘 작동함을 알 수 있었으며, 이를 통하여 멀티 터치 및 멀티 포스 터치가 가능함을 확인하였다. 본 연구에서 제작한 유연 투명 정전용량형 압력 센서는 유저인터페이스, 사용자 경험이 강조되고 있는 현재 상황에서 새로운 인터페이스의 터치스크린 패널에 대한 발전 가능성을 제시할 수 있을 것이라 판단된다. In this paper, we developed a flexible transparent capacitive pressure sensor which can recognize X and Y coordinates and the size of force simultaneously by sensing a change in electrical capacitance. The flexible transparent capacitive pressure sensor was composed of 3 layers which were top electrode, pressure sensing layer, and bottom electrode. Silver nanowire(Ag NW)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hybrid film was used for top and bottom flexible transparent electrode. The fabricated capacitive pressure sensor had a total size of 5 inch, and was composed of 11 driving line and 19 sensing line channels. The electrical, optical properties of the Ag NW/PEDOT:PSS and capacitive pressure sensor were investigated respectively. The mechanical flexibility was also investigated by bending tests. Ag NW/PEDOT:PSS exhibited the sheet resistance of $44.1{\Omega}/square$, transmittance of 91.1%, and haze of 1.35%. Notably, the Ag NW/PEDOT:PSS hybrid electrode had a constant resistance change within a bending radius of 3 mm. The bending fatigue tests showed that the Ag NW/PEDOT:PSS could withstand 200,000 bending cycles which indicated the superior flexibility and durability of the hybrid electrode. The flexible transparent capacitive pressure sensor showed the transmittance of 84.1%, and haze of 3.56%. When the capacitive pressure sensor was pressed with the multiple 2 mm-diameter tips, it can well detect the force depending on the applied pressure. This indicated that the capacitive pressure sensor is a promising scheme for next generation flexible transparent touch screens which can provide multi-tasking capabilities through simultaneous multi-touch and multi-force sensing.

전기용량성 섬유 압력센서를 이용한 호흡측정 시스템

민세동(Se-Dong Min),윤용현(Young-Hyun Yun),이충근(Chung-Keun Lee),신항식(Hang-Sik Shin),조하경(Ha-Kyung Cho),황선철(Seon-Cheol Hwang),이명호(Myoung-Ho Lee) 대한전기학회 2010 전기학회논문지 P Vol.59 No.1

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of 3.7997*10?? RPM, and lower limit of agreement of -3.8428*10?? RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

깔창 형태의 전기용량성 섬유압력센서를 이용한 보행 횟수 검출 및 자세 모니터링 시스템

민세동(Se-Dong Min),권춘기(Chun-Ki Kwon) 한국컴퓨터정보학회 2012 韓國컴퓨터情報學會論文誌 Vol.17 No.8

본 논문에서는 인간의 가장 기본적이며 기초적인 운동인 걸음걸이로부터 검출할 수 있는 걸음 수 및 보행분석을 위해 전도성 섬유를 이용한 전기용량성 압력 센서를 깔창형태로 개발하였다. 개발된 깔창 형태의 센서는 보행시의 압력을 측정하여 보행신호를 검출하고, 검출된 신호를 이용하여 걸음 수 및 자세에 따른 압력 분포를 관찰하였다. 개발된 센서의 성능 검증을 위하여 국제규격의 표준분동을 사용하여 0 kg에서 100 kg 까지 10 kg씩 증가하여 무게에 따른 압력변화를 관찰하였으며, 그 결과 압력에 따라 비선형적인 특성을 가지고 캐패시턴스 값이 증가함을 보였다. 자세에 따른 압력변화 실험과 보행 횟수 검출비교를 위한 실험에서는 건강한 성인남성 다섯 명을 대상으로 4가지의 서로 다른 자세로 있을 때의 압력 변화를 관찰하였고, 보행 횟수 검출을 위해서는 시속 1 km/h와 4 km/h의 두 가지 걸음속도에서 3분 동안 걷게 하여 보행신호를 검출하였다. 상용 만보계 및 관찰자의 수계로 도출된 보수를 비교하였다. 기존의 상용 만보계는 저속(1 km/h)으로 걸었을 때 보수가 잘 측정되지 않은 반면 개발된 센서는 저속에서도 관찰자 수계대비 정확한 보수를 도출 할 수 있었다(상용 만보계 대비 평균 98.06 %의 인식률). 또한 자세에 따라 압력 값을 토대로 사용자의 자세를 모니터링 할 수 있음을 보였다. 본 연구는 향후 스마트폰과 무선 연동하는 스마트 보행관리 시스템을 개발하기 위한 기초연구이다. We have developed a textile capacitive pressure sensor for smart gait analysis. The proposed system can convert sensor signal into step counts and pressure levels by different posture. To evaluate the performance of insole type textile capacitive sensor, we measured capacitance change by increment of weights from 10 kg to 100 kg with 10 kg increment using M1 class rectangular weights (four 20 kg weights and two 10 kg weights) which have ±10% tolerance. The result showed non-linearity characteristic of a general capacitive pressure sensor. The test was performed according to a test protocol for four different postures (sitting, standing, standing on a left leg and standing on a right leg) and different walking speeds (1 km/h and 4 km/h). Five healthy male subjects were participated in each test. As we expected, the pressure level was changed by pressure distribution according to posture. Also, developed textile pressure sensor showed higher recognition rate (average 98.06 %) than commercial pedometer at all walking speed. Therefore, the proposed step counts and posture monitoring system using conductive textile capacitive pressure sensor proved to be a reliable and useful tool for monitoring gait parameters.

2P-160 Piezo-capacitive sensor capable of detecting pressure and temperature

박병준,윤선근,장석태 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

There are many studies of demonstrating capactive sensors for various purposes, detecting physical variation. However, its perfoming principle is dependent on physical changes of dielectric layers. In this study, we developed a new class of microfluidic capacitive sensors with utilizing ionic liquid as electrodes and CNT/PDMS composites (CPCs) as a dielectric layer. The working principle of our sensors was investigated with geometrical changes of microfluidic channel and variations of electric double layer (EDL) capacitance. Our capacitive sensors showed detection of localized pressure, lateral pressure movement, and even temperature variations with high sensitivity. By using multimodal capability, the capacitive sensor was performed as a keypad and applied to a bottle and human skin. This capacitive sensors could offer great opportunity of development for future stretchable electronic devices such as wearable electronics, soft robotics, electronic skin, and healthcare systems.

Evaluation of Sensitivity and Linearity for Touch-mode Capacitive Pressure Sensor Measuring the Inner Bladder Pressure

이문규,전수민,김수진,김새웅,최범규 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

Recent studies have shown that pressure sensors for monitoring bladder pressure in real time are under way to develop treatments for urinary bladder dysfunction. Therefore, this study is designed to assess the sensitivity and linearity of touchmode capacitive pressure sensor (TMCPS), which is appropriate for measuring urinary bladder pressure. In addition, this study analyzes TMCPS’s ability responding to geometric design parameters. Finite element model consists of diaphragm and insulator plane. The modeling is based on three geometric design variables: size of square diaphragm, thickness of diaphragm and gap distance between diaphragm and insulator. The result from finite element analysis (FEA) based on those design variables can be used to produce capacitance-pressure (C-P) graph and the first order regression curve enables this study to analyze the sensitivity and linearity within 20~100cmH2O which is the measurable range of urinary bladder pressure. Regarding the effect on the thickness of diaphragm under the gap distance of 4μm corresponding to the square size of 2.6mm, this research shows that remarkable decline in sensitivity from 0.0031pF/cmH2O to 0.0022pF/cmH2O occurs as thickness increases from 11μm to 15μm. Even in the case of 5μm gap distance, sensitivity is shown to decrease from 0.0032pF/cmH2O to 0.0015pF/cmH2O as thickness increases from 11μm to 15μm. From a linearity point of view, however,it always marks higher value than 0.9 regardless of its thickness and describes relatively small deviation under 3.0mm. The study shows that as the size of diaphragm gets larger, sensitivity increases but linearity decreases. In addition, the thicker the diaphragm is, the less sensitivity the sensors are. However, the change in linearity turns out to be invalid. This research could be helpful in designing a touch-mode capacitive pressure sensor for urinary bladder pressure measurement.

Evaluation of Sensitivity and Linearity for Touch-mode Capacitive Pressure Sensor Measuring the Inner Bladder Pressure

Lee, Moon-Kyu,Jun, Su-Min,Kim, Su-Jin,Kim, Sae-Woong,Choi, Bum-Kyoo 한국정밀공학회 2011 International Journal of Precision Engineering and Vol.12 No.5

Recent studies have shown that pressure sensors for monitoring bladder pressure in real time are under way to develop treatments for urinary bladder dysfunction. Therefore, this study is designed to assess the sensitivity and linearity of touch-mode capacitive pressure sensor (TMCPS), which is appropriate for measuring urinary bladder pressure. In addition, this study analyzes TMCPS's ability responding to geometric design parameters. Finite element model consists of diaphragm and insulator plane. The modeling is based on three geometric design variables: size of square diaphragm, thickness of diaphragm and gap distance between diaphragm and insulator. The result from finite element analysis (FEA) based on those design variables can be used to produce capacitance-pressure (C-P) graph and the first order regression curve enables this study to analyze the sensitivity and linearity within 20~100cm$H_2O$ which is the measurable range of urinary bladder pressure. Regarding the effect on the thickness of diaphragm under the gap distance of 4 ${\mu}m$ corresponding to the square size of 2.6mm, this research shows that remarkable decline in sensitivity from 0.0031pF/cm$H_2O$ to 0.0022pF/cm$H_2O$ occurs as thickness increases from 11 ${\mu}m$ to 15 ${\mu}m$. Even in the case of 5 ${\mu}m$ gap distance, sensitivity is shown to decrease from 0.0032pF/cm$H_2O$ to 0.0015pF/cm$H_2O$ as thickness increases from 11 ${\mu}m$ to 15 ${\mu}m$. From a linearity point of view, however, it always marks higher value than 0.9 regardless of its thickness and describes relatively small deviation under 3.0mm. The study shows that as the size of diaphragm gets larger, sensitivity increases but linearity decreases. In addition, the thicker the diaphragm is, the less sensitivity the sensors are. However, the change in linearity turns out to be invalid. This research could be helpful in designing a touch-mode capacitive pressure sensor for urinary bladder pressure measurement.

세라믹소재를 이용한 해수압센서 제작 및 전기적 특성 연구

박성현,김은섭,정정균,Park, Sung-Hyun,Kim, Eun-Sup,Jung, Jung-Kyun 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.6

In this paper, we fabricated ceramic body and sapphire wafer in order to develop a hydraulic pressure sensor with high sensitivity and high temperature stability. The sapphire wafer was adopted with a membrane of capacitance ceramic pressure sensor. The capacitance value of the sensor for the finite element analysis(FEM) showed a linear pressure characteristics. Membrane was processed with a diameter of 32.4 mm and a thickness of 1 mm by using alumina powders. Ceramic body was processed with a diameter 32.4 mm and a thickness 5 mm. The capacitance pressure sensor was made with high heat treatment of the ceramic body and the sapphire wafer. Initially capacitance of the pressure sensor was 50 pF and a capacitance of 110 pF was measured from 5 bar pressure. Output voltage of 5 V was appeared at 5 bar pressure.

정전용량형 압력센서에서 센터 보스를 갖는 원형 다이어프램의 특성해석

조희찬 忠州大學校 2012 한국교통대학교 논문집 Vol.47 No.-

It is an effective to improve a structure and shape of a diaphragm as a sensing part for enhancing sensitivity and performance of a capacitive pressure sensor. Therefore, the characteristics of the circular diaphragm with a center boss in a capacitive pressure sensor have been studied for getting high performance in a low pressure in this paper. When the boss has a large radius in circular diaphragm, the capacitive pressure sensor has the higher sensitivity than that of the circular diaphragm which doesn’t have a boss structure in this research. But It is thought that the endurance of the diaphragm reduce for the reason of an excess shearing force to act on the diaphragm in the case of that the center boss radius is a more than about 36% of diaphragm radius.

Improved Capacitive Pressure Sensors Based on Liquid Alloy and Silicone Elastomer

Jungkeun Choi,Seokbeom Kim,Jungchul Lee,Bumkyoo Choi IEEE 2015 IEEE Sensors Journal Vol. No.

<P>This letter reports sensitivity-improved capacitive pressure sensors fabricated using liquid alloy and highly compliant silicon elastomer. Multilayer elastomer layers prepared by replica moulding were stacked and bonded to form three isolated disk-shaped cavities whose diameters are 3 or 5 mm. Top and bottom cavities (both are 200-μm tall) were filled with eutectic gallium-indium to realize compliant parallel electrodes. The cavity in the middle (1-mm tall) was left empty to make it compressed with applied pressure. The overall diameter and height of fabricated pressure sensors are 6 or 7.5 mm and 4 or 6 mm, respectively. After fabricated liquid alloy capacitive pressure sensors were connected with external inductors to construct LC resonant circuits, their resonance frequencies were characterized with applied pressures ranging from 0 to 10 kPa. We found that liquid-alloy capacitive pressure sensors exhibit improved sensitivities over identically sized sensors with solid electrodes.</P>

용량형 압력 센서의 설계 및 특성해석에 대한 기초적 연구

박창용,권현규,조지준 한국반도체디스플레이기술학회 2015 반도체디스플레이기술학회지 Vol.14 No.2

In this paper, a new capacitive pressure sensor has been proposed for a displacement measurement. The new sensor is mainly composed of a gap of 5μm and a notch of 1μm. And the sensor has the performance as the high sensitivity and capacitance compared with a commercial capacitive sensor. Therefore, the advantages of the new capacitive pressure sensor are good sensitivity in normal range, mechanically robust and large overload protection. The analytical model is induced for confirming the performance of the proposed sensor. In addition, FEM (finite elements method) simulation has been performed to verify the analytical model. Firstly, the displacement characteristics of diaphragm membrane were simulated by the analytical model and FEM in the case of different structure and materials. At last, through this analysis, these simulation results can be predicted the change of the performance when the device parameters are varied. And it is used as a design tool to achieve at a set of performance we desired.