Application of a Fringe Capacitive Sensor to Small-Distance Measurement

Wang, Dau-Chung; Chou, Jung-Chuan; Wang, Shih-Ming; Lu, Po-Lun; Liao, Lan-Pin

doi:10.1143/jjap.42.5816

Cited by 18 publications

(13 citation statements)

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“…Thus, the proposed proximity sensor with capacitive sensing units can extend the range of the sensing distance from 0.2–6.0 mm. This range is also found to vary with humidity of the surroundings and the obtained data could be fit well by a linear dependence of the maximum normalized relative resistance change over the proposed distance . Although we carried out all our experiments at 25 °C; we did in fact also investigated the effect of the temperature on the sensing abilities (Supporting Information, Figure S5).…”

Section: Resultsmentioning

confidence: 54%

Transparent and Flexible Cellulose Nanocrystal/Reduced Graphene Oxide Film for Proximity Sensing

Sadasivuni

Kafy

Zhai

et al. 2014

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The rapid development of touch screens as well as photoelectric sensors has stimulated the fabrication of reliable, convenient, and human-friendly devices. Other than sensors that detect physical touch or are based on pressure sensing, proximity sensors offer controlled sensibility without physical contact. In this work we present a transparent and eco-friendly sensor made through layer-by-layer spraying of modified graphene oxide filled cellulose nanocrystals on lithographic patterns of interdigitated electrodes on polymer substrates, which help to realize the precise location of approaching objects. Stable and reproducible signals generated by keeping the finger in close proximity to the sensor can be controlled by humidity, temperature, and the distance and number of sprayed layers. The chemical modification and reduction of the graphene oxide/cellulose crystal composite and its excellent nanostructure enable the development of proximity sensors with faster response and higher sensitivity, the integration of which resolves nearly all of the technological issues imposed on optoelectronic sensing devices.

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Section: Resultsmentioning

confidence: 54%

Transparent and Flexible Cellulose Nanocrystal/Reduced Graphene Oxide Film for Proximity Sensing

Sadasivuni

Kafy

Zhai

et al. 2014

Small

190

132

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“…Many researches are under their way developing the range of proximity measurement from micrometers to millimeters [36,37]. To date, the reported target objects for capacitive proximity sensors have been restricted to human finger and metal conductors, with limited distance resolution (below 100mm) [38,39].…”

Section: Introductionmentioning

confidence: 99%

Mathematical Model and Experimental Design of Nanocomposite Proximity Sensors

et al. 2020

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A mathematical model of fringe capacitance for a nano-based proximity sensor, which takes the presence of different resistivities into account, is developed. An analytical solution obtained for a rectangular-shape sensor with applying of Gauss, Conversation of Charge and Ohm laws into Laplace's equation 2 ( , , , ) = 0 gives the electric potential distribution by which the fringe capacitance in a 2D domain area can be calculated. The calculated capacitance evidently decreases drastically due to the fringe phenomena while object moves toward the polymeric sensor. The model also asserts that the change of capacitance is under a noticeable influence of sensor resistivity, particularly in the range of 10 3 -10 5 Ω.m, the initial capacitance varies from 0.045pF to 0.024 pF. The fabricated flexible nanocomposite sensors, Thermoplastic Polyurethane (TPU) reinforced by 1wt.% Carbon Nanotubes (CNTs) having resistivity 10P 5 P Ω.m, are capable of detecting presence of an external object in a wide range of distance and indicating remarkable correlation with the mathematical solution.Our proximity sensor fabrication is straightforward and relatively simple. An unprecedented detection range of measurement reveals promising ability of this proximity sensor in applications of motion analysis and healthcare systems.

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“…Figure 8 shows how a capacitive sensor works for displacement or distance measurement, and also reveals the performance parameters and the respective conditions on which they depend. For instance, the linear range relies on probe/electrode shape, size as well as electrode gap [5], [40], [41]; detection range dependents on sensing area, probe/electrode shape, target size, and driver as well; resolution and sensitivity rely on the same conditions as detection range [3]- [5], [40], [41]. Note that the driver includes excitation form (i.e.…”

Section: A Capacitive Displacement Sensing For Displacement/distance Measurementsmentioning

confidence: 99%

A Review on Applications of Capacitive Displacement Sensing for Capacitive Proximity Sensor

et al. 2020

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Capacitive proximity sensors (CPSs) are ubiquitous because of their simple design, low cost and low consumption. Capacitive displacement sensing, as one of the three sensing modalities, works for long distance and can be unitized to measure more physical quantities compared with capacitive volume and deformation sensing. In this paper, we firstly introduce the concept of capacitive displacement sensing. After that, we present applications of capacitive displacement sensing under three broad categories: distance measurements, indirect measurements, and the applications applied in smart environments. Finally, we discuss the challenges and possible solutions for CPSs development. We show that both the detection range and accuracy of CPS can be improved by multi-sensor fusion, and the application scenarios can be extensive through machine/deep learning approaches. We aim to provide a comprehensive, and state-of-theart review of the capacitive displacement sensing, and inspire more researchers and developers to find wide application perspectives.INDEX TERMS Capacitive proximity sensor (CPS), capacitive displacement sensing, distance measurement, indirect measurement, smart environment.

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Application of a Fringe Capacitive Sensor to Small-Distance Measurement

Cited by 18 publications

References 0 publications

Transparent and Flexible Cellulose Nanocrystal/Reduced Graphene Oxide Film for Proximity Sensing

Transparent and Flexible Cellulose Nanocrystal/Reduced Graphene Oxide Film for Proximity Sensing

Mathematical Model and Experimental Design of Nanocomposite Proximity Sensors

A Review on Applications of Capacitive Displacement Sensing for Capacitive Proximity Sensor

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