• Title/Summary/Keyword: Capacitive type sensor

Search Result 104, Processing Time 0.025 seconds

A Study on the On-machine Profile Measurement of Large Aspheric Form using Capasitive Sensor (정전용량센서를 이용한 대구경 비구면 형상의 기상측정에 관한 연구)

  • Kim, Geon-Hee;Won, Jonh-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.2 no.3
    • /
    • pp.56-61
    • /
    • 2003
  • This paper described about on-machine profile measurement of aspheric surfaces using contact probing technique in ultra precision machine. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime using a circle leaf spring mechanism and a capacitive-type sensor. The contact probe which is installed on the z-axis is In touch with the aspheric objects which is fixed on the spindle of the diamond turning machine(DTM) during the measuring procedure. The x, z-axis motions of the machine are monitored by a set of two orthogonal plane mirror type laser interferometers. As a results, the developed contact probe on-machine measurement system showed 10 nanometers repeatability with a ${\pm}2{\sigma}$ and uncertainty of 200 nmPv.

  • PDF

Investigation on Hermeticity of Liquid Crystal Polymer Package for MEMS Based Safety Device (MEMS 기반 안전 소자에 대한 액정 폴리머 패키지의 밀폐도 연구)

  • Choi, Jinnil;Kim, Yong-Kook;Ju, Byeong-Kwon
    • Journal of Sensor Science and Technology
    • /
    • v.24 no.5
    • /
    • pp.287-290
    • /
    • 2015
  • Liquid crystal polymer (LCP) is a thermoplastic polymer with superior mechanical and thermal properties. In addition, its characteristics include very low water absorption rate and possibility to apply bonding process under low temperature. In this study, LCP is utilized as a packaging material for a microelectronic system (MEMS) based safety device with suggestion of a low temperature packaging process. Highly sensitive and stable capacitive type humidity sensor is fabricated to investigate hermeticity of the packaged MEMS device.

Capacitive force sensor

  • Miyazawa, S.;Usui, Y.;Suzuki, M.;Baba, S.
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1994.10a
    • /
    • pp.611-615
    • /
    • 1994
  • In this paper, the sensitivity, linearity and temperature drift characteristics of various capacitive force sensors are evaluated and compared using new experimental methods. In particular, two designs were employed to reduce temperature drift. Both types of sensor use high-sensitivity Al coated PET film, and their externals are miniaturized. The first has a layered design consisting of two dielectric substances with different temperature characteristics. The prototype of this design had a temperature drift of only 0.1% of the sensor's capacity in the 20-80.deg. C range. The second type uses both a dummy sensor ind an active sensor with the same characteristics. The temperature drift of the prototype was one-fifth the temperature drift of a single sensor.

  • PDF

Fabrication of Capacitive-Type Humidity Sensor with Poly(p-phenylene ether sulfone) (폴리(페닐렌에테르설폰)을 이용한 용량형 습도센서의 제조)

  • Cho, Jae-Ick;Choi, Kyoon;Kim, Chang-Jung;Kim, Byung-Ik;Park, Sueng-Hyun;Bang, Gi-Suk
    • Polymer(Korea)
    • /
    • v.30 no.3
    • /
    • pp.207-209
    • /
    • 2006
  • We fabricated a capacitive-type humidity sensor using poly (p-phenylene ether sulfone: PES) as a humidity sensitive layer. The PES was dissolved in m-cresol $(CH_3C_6H_4OH)$ and spin-coated on ITO-coated glass substrate. Gold was deposited by sputtering as a water-permeable upper electrode. The capacitance of the sensor was inversely proportional to sensing film thicknesses and showed an excellent linearity of less than 1% in the humidity range of 20 to 90%. The sensor haying a $1.4{\mu}m$ sensing layer showed a hysteresis of 1.3% and a good sensitivity of 1.14 at 20 kHz.

Development of Inductive and Capacitive Type Intraocular Pressure (IOP) Sensor to Improve Sensitivity and Minimize Size (민감도 향상과 센서 소형화를 위한 자기 및 용량형 안압센서의 개발)

  • Jang, Cheol In;Shin, Kyeong-Sik;Yun, Kwang-Seok;Kim, Yong Woo;Kang, Ji Yoon;Lee, Soo Hyun
    • Journal of Sensor Science and Technology
    • /
    • v.23 no.6
    • /
    • pp.409-415
    • /
    • 2014
  • We had presented an inductive type intraocular pressure sensor (L-sensor) in previous work. The distance between a micro coil and a ferrite on the membrane was modulated by pressure, and as a result the inductance and resonant frequency were changed. However, L-sensor has some problems to implant in eyes. First problem is low sensitivity. When L-sensor was implanted in rabbit's eyes, resonant frequency of L-sensor was very hard to detect. Second problem is biocompatibility. Size of L-sensor is $6{\times}7{\times}1.2mm$. When L-sensor was implanted in the eyes, it caused the inflammation. Therefore, this study suggests an inductive and capacitive type IOP sensor (LCsensor). The sensitivity of the LC-sensor 27.3 kHz/mmHg under 60mmHg. It is much larger than 14 kHz/mmHg of the L-sensor. And the size of LC-sensor is 47% smaller than L-sensor. After 2 weeks from the implantation of LC-sensor into rabbit eyes, we measured the changes of resonant frequency of LC-sensor according to increased IOP by Balanced Salt Solution (BSS) injection. As a result, the sensitivity of LC-sensor in in vivo test is 25 kHz/mmHg. That is similar to the sensitivity of in vitro test.

Preceding Study on the Sensing Part of Level Measurement System of Launch Vehicle Propellant Tanks (발사체 탱크 추진제 수위 측정시스템 감지부 선행연구)

  • Shin, Dong-Sun;Lee, Eung-Shin;Ko, Hyun-Seok;Cho, In-Hyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2009.11a
    • /
    • pp.54-57
    • /
    • 2009
  • The propellant level measurement system of the next Koreanized launch vehicle shall adapt a capacitive type sensor, which can generate capacitive values continuously considering cryogenic environment and the characteristics of flowrate control. At present there are a twin-arc and a triple-arc methods as a capacitive type signal sensing method. In this study a highly accurate triple-arc method, which can apply to almost all fluids, is chosen. In this paper the review results on the principle of triple-arc sensing, the analysis results on the influence on capacitive values due to shape change of sensing part, and the simulation results to monitor the influence on signal sensing according to the location of sensing part in the upper part of propellant tank are included. Information obtained from this study can be used in the designing and manufacturing of on-board propellant level measurement system in tanks.

  • PDF

A Highly Sensitive Humidity Sensor Using a Modified Polyimide Film

  • Kim, Yong-Ho;Lee, Joon-Young;Kim, Yong-Jun;Kim, Jung-Hyun
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.4 no.2
    • /
    • pp.128-132
    • /
    • 2004
  • This paper presents the design, fabrication sequence and measurement results of a highly sensitive capacitive-type humidity sensor using a polyimide film without hydrophobic elements. The structure of the humidity sensor is MIM (metalinsulator-metal). For a high sensitivity, a modified aromatic polyimides as a moisture absorbing layer has been synthesized instead of using general polyimides containing hydrophobic elements. The polyimide film was obtained by synthesizing and thermally polymerizing polyamic acid composed of m-pyromellitic dianhydride, phenelenediamine and dimethylacetamide. Characteristics of fabricated sensors which include sensitivity, hysteresis and stability have been measured. The measurement result shows the percent normalized capacitance change of 0.37/%RH over a range from 10 to 90%RH, hysteresis of 0.77% over the same %RH range and maximum drift of 0.25% at 50%RH. The result shows that the developed humidity sensor can be applied to evaluate a hermeticity of various sensors and actuator systems as well as micro packages.

A Capacitive Type Humidity Sensor Using a Polyimide Film for Hermeticity Measurement of Micro Packages (마이크로 패키지의 밀폐도 측정을 위한 정전용량형 폴리이미드 습도센서)

  • Kim, Yong-Ho;Kim, Yong-Jun;Kim, Kyung-Il;Kim, Joong-Hyun
    • Journal of Sensor Science and Technology
    • /
    • v.13 no.4
    • /
    • pp.287-291
    • /
    • 2004
  • A capacitive type humidity sensor has been fabricated using a polyimide film without hydrophobic elements and its characteristics has been evaluated for hermeticity measurement of micro packages. For a highly sensitive humidity sensor, a polyimide film without hydrophobic elements has been synthesized and used instead of using a commercial one in which 7 group elements such as fluorine or chlorine are included. Sensitivity, stability and hysteresis has been performed to characterize the fabricated sensors. The sensitivity defined as normalized percent capacitance change was 0.3751%RH and hysteresis was 0.77% in the range of 10%RH to 90%RH. Maximum deviation from the average capacitance measured for 120 minutes at 50%RH was 0.25%. The proposed humidity sensor can be used for hermeticity measurement of micro packages.

A study on the development of a environment-friendly vehicle device (친환경 자동차 부품 개발에 대한 연구)

  • Lee Eung-Shin;Lee Jang Moo;Song Jun Gyu
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.335-338
    • /
    • 2005
  • Starting with the development of environmentally friendly electric controlled engine, sensors have played an increasing role in automotive technology. Electric power steering (EPS) systems are more and more replacing hydraulic systems. To improve fuel economy, the power assistance is provided by an electric drive. In this paper, development of a unique torque sensor for EPS is introduced. A capacitive type torque sensor is concluded to be suitable for EPS because its output is accurate, linear and robust against the variance of temperature, and patents have not applied so much.

  • PDF

Innovative Differential Hall Effect Gap Sensor through Comparative Study for Precise Magnetic Levitation Transport System

  • Lee, Sang-Han;Park, Sang-Hui;Park, Se-Hong;Sohn, Yeong-Hoon;Cho, Gyu-Hyeong;Rim, Chun-Taek
    • Journal of Sensor Science and Technology
    • /
    • v.25 no.5
    • /
    • pp.310-319
    • /
    • 2016
  • Three types of gap sensors, a capacitive gap sensor, an eddy current gap sensor, and a Hall effect gap sensor are described and evaluated through experiments for the purpose of precise gap sensing for micrometer scale movement, and a novel type of differential hall effect gap sensor is proposed. Each gap sensor is analyzed in terms of resolution and environment dependency including temperature dependency. Furthermore, a transport system for AMOLED deposition is introduced as a typical application of gap sensors, which are recently receiving considerable attention. Based on the analyses, the proposed differential Hall effect gap sensor is found to be the most suitable gap sensor for precise gap sensing, especially for application to a transport system for AMOLED deposition. The sensor shows resolution of $0.63mV/{\mu}m$ for the overall range of the gap from 0 mm to 2.5 mm, temperature dependency of $3{\mu}m/^{\circ}C$ from $20^{\circ}C$ to $30^{\circ}C$, and a monotonic characteristic for the gap between the sensor and the target.