• Title/Summary/Keyword: Capacitive pressure sensor

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The development of a variable capacitive pressure sensor for TPMS(tire pressure monitoring system) (TPMS 적용을 위한 가변 정전 용량형 압력센서 개발)

  • Choi, Bum-Koo;Kim, Do-Hyung;Oh, Jae-Geun
    • Journal of Sensor Science and Technology
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    • v.14 no.4
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    • pp.265-271
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    • 2005
  • In this study, a variable capacitive pressure sensor is fabricated for TPMS (Tire Pressure Monitoring System). This study is for developing sensors which consecutively measure the tire pressure given as 30 psi from the industrial standard. For improving non-linearity of the prior capacitive pressure sensors, it is suggested that touch mode capacitive pressure sensor be applied. In addition, initial capacitance is designed as small as possible for the conformity to the wireless sensor. ANSYS, commercial FEA package, is used for designing and simulating the sensor. The device is progressed by MEMS (Micro Electro Mechanical Systems) fabrication and packaged with PDMS. The result is obtained sensitivity, 1 pF/psi, through a pressure test. The simulation result is discrepant from experiment one. Wafer's uniformity is presumed as the main reason of discrepancy.

Finite Element Analysis of Capacitive pressure sensor with Touch mode for improving non-linearity (비선형성의 개선을 위한 Capacitive pressure sensor의 Touch mode 방식에 대한 유한요소 해석)

  • Kim, Do-Hyung;O, Jea-Geun;Choi, Bum-Kyoo
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.2087-2089
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    • 2004
  • Capacitive pressure sensor는 Piezo type sensor에 비해 온도의 영향이 적어 공업계측, 전기용품 등 그 용도가 다양하여 폭넓게 사용되어지고 있지만, 측정값의 비선형성이 존재하여 측정값에 대한 신뢰도가 떨어지는 단점이 있다. 본 연구에서는 기존 capacitive pressure sensor의 비선형적 output을 개선하기 위한 방법으로 touch mode capacitive pressure sensor를 제안하였다. 또한, 실제 Device제작에 앞서 FEM 해석을 수행하였다. 2mm X 2mm 크기의 diaphragm, $25{\mu}m$의 두께, $20{\mu}m$의 gap을 갖는 Sensor를 Simulation하였으며 설계 변수를 추출하여 각각의 설계변수에 대한 해석을 실시하였다. 그 결과 15.2psi${\sim}$31psi의 영역에서 8.58pF${\sim}$54.31pF의 capacitance가 선형적으로 나타나는 sensor임을 확인하였다.

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Respiration Measurement System using Textile Capacitive Pressure Sensor (전기용량성 섬유 압력센서를 이용한 호흡측정 시스템)

  • Min, Se-Dong;Yun, Young-Hyun;Lee, Chung-Keun;Shin, Hang-Sik;Cho, Ha-Kyung;Hwang, Seon-Cheol;Lee, Myoung-Ho
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.1
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    • pp.58-63
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    • 2010
  • 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 $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ 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.

Development of Capacitive-type Pressure Mapping Sensor using Printing Technology

  • Lee, Young-Tae
    • Journal of Sensor Science and Technology
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    • v.26 no.1
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    • pp.24-27
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    • 2017
  • In this study, I developed a simple and low cost process-printing a silver, carbon, dielectric, adhesive layer on PET films using screen printing technology and bonding the two films face-to-face-to fabricate a low price capacitive pressure-mapping sensor. Both electrodes forming the pressure measuring capacitor are arranged between the two PET films similar to a sandwich. Therefore, the sensor has the advantage of minimizing the influence of external noise. In this study, a $10{\times}10$ capacitance-type pressure-mapping sensor was fabricated and its characteristics were analyzed.

Development of a Lock-In Amplifier Array for Capacitive Type Pressure Mapping Sensor (정전용량 형 압력맵핑센서를 위한 록인 증폭기 어레이 개발)

  • Kim, Cheong-Worl;Lee, Young-Tae
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.4
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    • pp.63-67
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    • 2017
  • In this study, We developed a simple and low cost capacitive pressure mapping sensor and microcontroller-base lock-in amplifier array. We developed capacitive type pressure mapping sensor by forming the electrode and adhesives on plastic films using only the printing process, and the finishing the process by bonding the two films. Lock-in amplifier array was based on a general purpose microcontroller and had only a charge amplifier as analog circuits. In this study, a $10{\times}10$ capacitive type pressure mapping sensor and lock-in amplifier array was fabricated and its characteristics were analyzed.

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Research for Design and Characteristic Interpretation of Capacitive Pressure Sensor Structure (용량형 압력 센서의 설계 및 특성해석에 대한 기초적 연구)

  • Park, Chang Yong;Kweon, Hyun Kyu;Zhao, Zhi Jun
    • Journal of the Semiconductor & Display Technology
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    • v.14 no.2
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    • pp.1-7
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    • 2015
  • 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 $5{\mu}m$ and a notch of $1{\mu}m$. 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.

Characteristics of Surface Micromachined Capacitive Pressure Sensors for High Temperature Applications (표면 MEMS 기술을 이용한 고온 용량형 압력센서의 특성)

  • Seo, Jeong-Hwan;Noh, Sang-Soo;Kim, Kwang-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.4
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    • pp.317-322
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    • 2010
  • This paper reports the fabrication and characterization of surface micromachined poly 3C-SiC capacitive pressure sensors on silicon wafer operable in touch mode and normal mode for high temperature applications. FEM(finite elements method) simulation has been performed to verify the analytical mode. The sensing capacitor of the capacitive pressure sensor is composed of the upper metal and the poly 3C-SiC layer. Measurements have been performed in a temperature range from $25^{\circ}C$ to $500^{\circ}C$. Fabrication process of designed poly 3C-SiC touch mode capacitive pressure sensor was optimized and would be applicable to capacitive pressure sensors that are required high precision and sensitivity at high pressure and temperature.

Design and Fabrication of Capacitive Pressure Sensor (용량형 압력센서의 설계 및 제작)

  • 이승준;김병태;권영수;정귀상
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.561-564
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    • 2000
  • Silicon capacitive pressure sensor has been fabricated by using electrochemical etching stop and silicon-to-glass electrostatic bonding technique. A diaphragm structure is designed to compensate the nonlinear response. A cavity is etched into the silicon to the depth of 2$\mu\textrm{m}$ by anisotropic etching in 20wt.% TMAH solution at 80$^{\circ}C$. A fabricated sensor showed 3.3 pF zero-pressure capacitance, 297 pp.m/mmHg sensitivity, and a 7.4 7%F.S. nonlinear response in a 0-1 kgf/cm$^2$pressure range.

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A Study on Electrical Characteristics of a Capacitive Pressure Sensor Element to Measure the Pressure of Refrigerant of Air-Conditioner (에어컨 냉매압 측정용 정전용량형 압력센서 소자의 전기적 특성 연구)

  • Choi, Ga-Hyun;Chung, Woo-Young;Choi, Jung-Woon;Kim, Si-Dong;Min, Joon-Won
    • Journal of Sensor Science and Technology
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    • v.24 no.3
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    • pp.208-213
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    • 2015
  • The purpose of this study is to optimize the design of a capacitive pressure sensor element using the simulation of electrical characteristics. The simulation of the ceramic sensor diaphragm ($Al_2O_3$) was performed by permitting pressure to change the curvature of the diaphragm. The pressure capacitance ($C_P$) was increased from 19.63 pF to 15.26 pF by applying pressure because the distance between the electrodes has been changed from $30{\mu}m$ to $15{\mu}m$. When the thickness of the diaphragm was changed to 0.46~0.52 mm, a larger capacitance change showed in accordance with the reduced thickness, which means an increase of sensitivity. However, considering the viewpoint of the signal linearity, it was selected for the optimum thickness of the diaphragm to 0.50 mm. The designed sensor element based on simulated results was tested to measure the output characteristics. Comparing of simulated and measured results, there was a margin of error of approximately 2%.

Calibration of SAW Based Capacitive Sensor Using Lumped Component and High Precision Gap Measurement (집중 소자를 이용한 표면 탄성파 장치 기반의 용량 성 센서 보정 및 이를 이용한 초정밀 간극 측정)

  • Kim, Jae-Geun;Ko, Byung-Han;Park, Young-Pil;Park, No-Cheol
    • Transactions of the Society of Information Storage Systems
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    • v.8 no.1
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    • pp.16-21
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    • 2012
  • SAW device is widely used as filters, sensors, actuators in various technologies. And capacitive sensor is tremendously used to measure pressure, gap, etc. The application of SAW device as signal conditioner of capacitive sensor reduces noise level and enables high precision measurement. The response increase of SAW based capacitive sensor is produced just before the two capacitive electrode contacts by the existence of parasitic resistance of capacitive electrode. In this paper, we analyze the effects of parasitic resistance and propose the calibrating method using lumped component and execute the high precision gap measurement using calibrated system. And xx nm resolution and yy ${\mu}m$ stroke was attained.