scholarly journals Novel Design and Fabrication of High Sensitivity MEMS Capacitive Sensor Array for Fingerprint Imaging

2009 ◽  
Vol 74 ◽  
pp. 239-242 ◽  
Author(s):  
Mitra Damghanian ◽  
Burhanuddin Yeop Majlis

A novel MEMS capacitive pressure sensor array is designed and fabricated for fingerprint acquisition application. Based on analytical investigations and FEM analysis, the designed structure of pressure sensor cells assist from an aluminum clamped-clamped wide beam as the movable electrode of variant capacitor, instead of usual membrane structure. A rectangular base T-shape protrusion is also used on top of the deflecting electrode to concentrate pressure and increase the sensitivity. Proven by the real test of the fabricated sensor structure, this design has enhanced sensitivity and linearity of the device compared to all membrane based reported prototypes without crossing the dpi limits. Structural modifications have resulted in a simpler fabrication process as well.

2020 ◽  
Vol 8 (4) ◽  
pp. 296-307
Author(s):  
Konstantin Krestovnikov ◽  
Aleksei Erashov ◽  
Аleksandr Bykov

This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 442
Author(s):  
Kyobin Keum ◽  
Jae Sang Heo ◽  
Jimi Eom ◽  
Keon Woo Lee ◽  
Sung Kyu Park ◽  
...  

Textile-based pressure sensors have garnered considerable interest in electronic textiles due to their diverse applications, including human–machine interface and healthcare monitoring systems. We studied a textile-based capacitive pressure sensor array using a poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP)/ionic liquid (IL) composite film. By constructing a capacitor structure with Ag-plated conductive fiber electrodes that are embedded in fabrics, a capacitive pressure sensor showing high sensitivity, good operation stability, and a wide sensing range could be created. By optimizing the PVDF-HFP:IL ratio (6.5:3.5), the fabricated textile pressure sensors showed sensitivity of 9.51 kPa−1 and 0.69 kPa−1 in the pressure ranges of 0–20 kPa and 20–100 kPa, respectively. The pressure-dependent capacitance variation in our device was explained based on the change in the contact-area formed between the multi-filament fiber electrodes and the PVDF-HFP/IL film. To demonstrate the applicability and scalability of the sensor device, a 3 × 3 pressure sensor array was fabricated. Due to its matrix-type array structure and capacitive sensing mechanism, multi-point detection was possible, and the different positions and the weights of the objects could be identified.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ruzhan Qin ◽  
Mingjun Hu ◽  
Xin Li ◽  
Te Liang ◽  
Haoyi Tan ◽  
...  

AbstractThe development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices, but it is still a great challenge to fabricate capacitive sensors with high sensitivity. Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors. In this work, a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone (PVP) by an interdigital electrode is reported. By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer, the sensitivity of the capacitive sensor can be improved. The capacitive sensor based on MXene/PVP here has a high sensitivity (~1.25 kPa−1), low detection limit (~0.6 Pa), wide sensing range (up to 294 kPa), fast response and recovery times (~30/15 ms) and mechanical stability of 10000 cycles. The presented sensor here can be used for various pressure detection applications, such as finger pressing, wrist pulse measuring, breathing, swallowing and speech recognition. This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics.


Author(s):  
Jing Wang ◽  
Longwei Li ◽  
Lanshuang Zhang ◽  
Panpan Zhang ◽  
Xiong Pu

Abstract Highly sensitive soft sensors play key roles in flexible electronics, which therefore have attracted much attention in recent years. Herein, we report a flexible capacitive pressure sensor with high sensitivity by using engineered micro-patterned porous polydimethylsiloxane (PDMS) dielectric layer through an environmental-friendly fabrication procedure. The porous structure is formed by evaporation of emulsified water droplets during PDMS curing process, while the micro-patterned structure is obtained via molding on sandpaper. Impressively, this structure renders the capacitive sensor with a high sensitivity up to 143.5 MPa-1 at the pressure range of 0.068~150 kPa and excellent anti-fatigue performance over 20,000 cycles. Meanwhile, the sensor can distinguish different motions of the same person or different people doing the same action. Our work illustrates the promising application prospects of this flexible pressure sensor for the security field or human motion monitoring area.


Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 371 ◽  
Author(s):  
Mengmeng Li ◽  
Jiaming Liang ◽  
Xudong Wang ◽  
Min Zhang

Flexible pressure sensors with a high sensitivity in the lower zone of a subtle-pressure regime has shown great potential in the fields of electronic skin, human–computer interaction, wearable devices, intelligent prosthesis, and medical health. Adding microstructures on the dielectric layer on a capacitive pressure sensor has become a common and effective approach to enhance the performance of flexible pressure sensors. Here, we propose a method to further dramatically increase the sensitivity by adding elastic pyramidal microstructures on one side of the electrode and using a thin layer of a dielectric in a capacitive sensor. The sensitivity of the proposed device has been improved from 3.1 to 70.6 kPa−1 compared to capacitive sensors having pyramidal microstructures in the same dimension on the dielectric layer. Moreover, a detection limit of 1 Pa was achieved. The finite element analysis performed based on electromechanical sequential coupling simulation for hyperelastic materials indicates that the microstructures on electrode are critical to achieve high sensitivity. The influence of the duty ratio of the micro-pyramids on the sensitivity of the sensor is analyzed by both simulation and experiment. The durability and robustness of the device was also demonstrated by pressure testing for 2000 cycles.


2020 ◽  
Vol 8 (33) ◽  
pp. 11468-11476
Author(s):  
Wei Li ◽  
Xin Jin ◽  
Yide Zheng ◽  
Xudong Chang ◽  
Wenyu Wang ◽  
...  

Capacitive sensor combining highly porous PDMS and rough polypyrrole electrodes improves the device range and sensitivity.


Author(s):  
Zhibang Chen ◽  
Wei Du ◽  
Feng Zhao

In this paper, we investigated a new capacitive pressure sensor structure on a silicon carbide (SiC) platform for high sensitivity and harsh environment operation capability. The superior material properties of SiC ensure robustness of the new sensor to withstand large-scale pressure at high temperature and in chemical/biological medium. The sensor structure consists of a circular SiC diaphragm suspended by four arms over a SiC substrate, with design to enable diaphragm to deflect nearly uniformly with applied pressure. This configuration results in improved sensing properties. With high sensitivity and operation capability in hostile environment, this new pressure sensor is promising for use in a wide range of applications such as automotive, nuclear station, aerospace, and oil/gas exploration, etc.


2016 ◽  
Vol 5 (1) ◽  
pp. 95-112 ◽  
Author(s):  
Ali E. Kubba ◽  
Ahmed Hasson ◽  
Ammar I. Kubba ◽  
Gregory Hall

Abstract. Measuring air pressure using a capacitive pressure sensor is a robust and precise technique. In addition, a system that employs such transducers lies within the low power consumption applications such as wireless sensor nodes. In this article a high sensitivity with an elliptical diaphragm capacitive pressure sensor is proposed. This design was compared with a circular diaphragm in terms of thermal stresses and pressure and temperature sensitivity. The proposed sensor is targeted for tyre pressure monitoring system application. Altering the overlapping area between the capacitor plates by decreasing the effective capacitance area to improve the overall sensitivity of the sensor (ΔC ∕ C), temperature sensitivity, and built-up stresses is also examined in this article. Theoretical analysis and finite element analysis (FEA) were employed to study pressure and temperature effects on the behaviour of the proposed capacitive pressure sensor. A MEMS (micro electro-mechanical systems) manufacturing processing plan for the proposed capacitive sensor is presented. An extra-low power short-range wireless read-out circuit suited for energy harvesting purposes is presented in this article. The developed read-out circuitry was tested in terms of sensitivity and transmission range.


2021 ◽  
pp. 1-1
Author(s):  
Valliammai Palaniappan ◽  
Masoud Panahi ◽  
Dinesh Maddipatla ◽  
Xingzhe Zhang ◽  
Simin Masihi ◽  
...  

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