Flexible pressure sensor with a “V-type” array microelectrode on a grating PDMS substrate

Sensor Review ◽  
2016 ◽  
Vol 36 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Jianli Cui ◽  
Junping Duan ◽  
Binzhen Zhang ◽  
Xueli Nan
Keyword(s):  
Pressure Sensor ◽  
Nanoimprint Lithography ◽  
Pressure Sensors ◽  
Weight Ratio ◽  
Master Mold ◽  
Pdms Substrate ◽  
Cycle Stability ◽  
Molding Process ◽  
Content Type ◽  
Array Structure

Purpose This paper aims to provide a fabrication and measurement of a highly stretchable pressure sensor with a “V-type” array microelectrode on a grating PDMS substrate. Design/methodology/approach First, the “V-type” array structure on the silicon wafer was fabricated by the MEMS technology, and the fabrication process included ultra-violet lithography and silicon etching. The “V-type” array structure on the master mold was then replicated into polycarbonate, which served as an intermediate, negative mold, using a conventional nanoimprint lithography technique. The negative mold was subsequently used in the PDMS molding process to produce PDMS “V-type” array structures with the same structures as the master mold. An Ag film was coated on the PDMS “V-type” array structure surface by the magnetron sputtering process to obtain PDMS “V-type” array microelectrodes. Finally, a PDMS prepolymer was prepared using a Sylgard184 curing agent with a weight ratio of a 20:1 and applied to the cavity at the middle of the two-layer PDMS “V-type” array microelectrode template to complete hot-press bonding, and a pressure sensor was realized. Findings The experimental results showed that the PDMS “V-type” array microelectrode has high stretchability of 65 per cent, temperature stability of 0.0248, humidity stability of 0.000204, bending stability and cycle stability. Capacitive pressure sensors with a “V-type” array microelectrode exhibit ideal initial capacitance (111.45 pF), good pressure sensitivity of 0.1143 MPa-1 (0-0.35 Mpa), fast response and relaxation times (<200 ms), high bending stability, high temperature/humidity stability and high cycle stability. Originality/value The PDMS “V-type” array structure microelectrode can be used to fabricate pressure sensors and is highly flexible, crack-free and durable.

Self-powered flexible pressure sensors based on nanopatterned polymer films

Sensor Review ◽  
2020 ◽  
Vol 40 (6) ◽  
pp. 629-635
Author(s):  
Man Zhang ◽  
Liangping Xia ◽  
Suihu Dang ◽  
Lifang Shi ◽  
Axiu Cao ◽  
...  
Keyword(s):  
Polymer Films ◽  
Pressure Sensor ◽  
Nanoimprint Lithography ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Pressure Sensors ◽  
The Self ◽  
Content Type ◽  
Self Powered ◽  
Flexible Pressure Sensor

Purpose The pressure sensors can convert external pressure or mechanical deformation into electrical power and signal, which cannot only detect pressure or strain changes but also harvest energy as a self-powered sensor. This study aims to develop a self-powered flexible pressure sensor based on regular nanopatterned polymer films. Design/methodology/approach In this paper, the self-powered flexible pressure sensor is mainly composed of two nanopatterned polymer films and one conductive electrode layer between them, which is a sandwich structure. The regular nanostructures increase the film roughness and contact area to enhance the friction effect. To enhance the performance of the pressure sensor, different nanostructures on soft polymer sensitive layers are fabricated using UV nanoimprint lithography to generate more triboelectric charges. Findings Finally, the self-powered flexible pressure sensor is prepared, which consists of sub-200 nm resolution regular nanostructures on the surface of the elastic layer and an indium tin oxide electrode thin film. By converting the friction mechanical energy into electrical power, a maximum power of 423.8 mW/m2 and the sensitivity of 0.8 V/kPa at a frequency of 5 Hz are obtained, which proves the excellent sensing performance of the sensor. Originality/value The acquired electrical power and pressure signal by the sensor would be processed in the signal process circuit, which is capable of immediately and sustainably driving the highly integrated self-powered sensor system. Results of the experiments show that this new pressure sensor is a potential method for personal pressure monitoring, featured as being wearable, cost-effective, non-invasive and user-friendly.

scholarly journals Complex conductivity reconstruction in multiple frequency electrical impedance tomography for fabric-based pressure sensor

Sensor Review ◽  
2015 ◽  
Vol 35 (1) ◽  
pp. 85-97 ◽  
Author(s):  
C.L. Yang ◽  
A. Mohammed ◽  
Y Mohamadou ◽  
T. I. Oh ◽  
M. Soleimani
Keyword(s):  
Electrical Impedance Tomography ◽  
Pressure Sensor ◽  
Electrical Impedance ◽  
Pressure Sensors ◽  
Complex Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Multiple Frequency ◽  
Impedance Tomography ◽  
Content Type ◽  
Pressure Mapping

Purpose – The aim of this paper is to introduce and to evaluate the performance of a multiple frequency complex impedance reconstruction for fabric-based EIT pressure sensor. Pressure mapping is an important and challenging area of modern sensing technology. It has many applications in areas such as artificial skins in Robotics and pressure monitoring on soft tissue in biomechanics. Fabric-based sensors are being developed in conjunction with electrical impedance tomography (EIT) for pressure mapping imaging. This is potentially a very cost-effective pressure mapping imaging solution in particular for imaging large areas. Fabric-based EIT pressure sensors aim to provide a pressure mapping image using current carrying and voltage sensing electrodes attached on the boundary of the fabric patch. Design/methodology/approach – Recently, promising results are being achieved in conductivity imaging for these sensors. However, the fabric structure presents capacitive behaviour that could also be exploited for pressure mapping imaging. Complex impedance reconstructions with multiple frequencies are implemented to observe both conductivity and permittivity changes due to the pressure applied to the fabric sensor. Findings – Experimental studies on detecting changes of complex impedance on fabric-based sensor are performed. First, electrical impedance spectroscopy on a fabric-based sensor is performed. Secondly, the complex impedance tomography is carried out on fabric and compared with traditional EIT tank phantoms. Quantitative image quality measures are used to evaluate the performance of a fabric-based sensor at various frequencies and against the tank phantom. Originality/value – The paper demonstrates for the first time the useful information on pressure mapping imaging from the permittivity component of fabric EIT. Multiple frequency EIT reconstruction reveals spectral behaviour of the fabric-based EIT, which opens up new opportunities in exploration of these sensors.

Design, development and performance evaluation of pressure sensor using eddy current displacement sensing coil

Sensor Review ◽  
2018 ◽  
Vol 38 (2) ◽  
pp. 248-258
Author(s):  
Gobi K. ◽  
Kannapiran B. ◽  
Devaraj D. ◽  
Valarmathi K.
Keyword(s):  
Performance Evaluation ◽  
Eddy Current ◽  
Pressure Sensor ◽  
Strain Gauge ◽  
Pressure Sensors ◽  
Calibration Data ◽  
Position Measurement ◽  
Content Type ◽  
Short Period ◽  
Type Pressure

Purpose The conventional strain gauge type pressure sensor suffers in static testing of engines due to the contact transduction method. This paper aims to focus on the concept of non-contact transduction-based pressure sensor using eddy current displacement sensing coil (ECDS) to overcome the temperature limitations of the strain gauge type pressure sensor. This paper includes the fabrication of prototypes of the proposed pressure sensor and its performance evaluation by static calibration. The fabricated pressure sensor is proposed to measure pressure in static test environment for a short period in the order of few seconds. The limitations of the fabricated pressure sensor related to temperature problems are highlighted and the suitable design changes are recommended to aid the future design. Design/methodology/approach The design of ECDS-based pressure sensor is aimed to provide non-contact transduction to overcome the limitations of the strain gauge type of pressure sensor. The ECDS is designed and fabricated with two configurations to measure deflection of the diaphragm corresponding to the applied pressure. The fabricated ECDS is calibrated using a standard micro meter to ensure transduction within limits. The fabricated prototypes of pressure sensors are calibrated using dead weight tester, and the calibration results are analyzed to select the best configuration. The proposed pressure sensor is tested at different temperatures, and the test results are analyzed to provide recommendations to overcome the shortcomings. Findings The performance of the different configurations of the pressure sensor using ECDS is evaluated using the calibration data. The analysis of the calibration results indicates that the pressure sensor using ECDS (coil-B) with the diaphragm as target is the best configuration. The accuracy of the fabricated pressure sensor with best configuration is ±2.8 per cent and the full scale (FS) output is 3.8 KHz. The designed non-contact transduction method extends the operating temperature of the pressure sensor up to 150°C with the specified accuracy for the short period. Originality/value Most studies of eddy current sensing coil focus on the displacement and position measurement but not on the pressure measurement. This paper is concerned with the design of the pressure sensor using ECDS to realize the non-contact transduction to overcome the limitations of strain gauge type pressure sensors and evaluation of the fabricated prototypes. It is shown that the accuracy of the proposed pressure sensor is not affected by the high temperature for the short period due to non-contact transduction using ECDS.

Single-chip solution for electronics unit of a smart pressure sensor

Sensor Review ◽  
2020 ◽  
Vol 40 (5) ◽  
pp. 529-534
Author(s):  
Igor S. Nadezhdin ◽  
Aleksey G. Goryunov
Keyword(s):  
Pressure Sensor ◽  
Sensitive Element ◽  
Noise Immunity ◽  
Pressure Sensors ◽  
Cost Effective ◽  
Differential Pressure ◽  
Manufacturing Cost ◽  
Content Type ◽  
Differential Pressure Sensor ◽  
Developed Pressure

Purpose Differential pressure is an important technological parameter, one urgent task of which is control and measurement. To date, the lion’s share of research in this area has focused on the development and improvement of differential pressure sensors. The purpose of this paper is to develop a smart differential pressure sensor with improved operational and metrological characteristics. Design/methodology/approach The operating principle of the developed pressure sensor is based on the capacitive measurement principle. The measuring unit of the developed pressure sensor is based on a differential capacitive sensitive element. Programmable system-on-chip (PSoC) technology has been used to develop the electronics unit. Findings The use of a differential capacitive sensitive element allows the unit to compensate for the influence of interference (for example, temperature) on the measurement result. With the use of PSoC technology, it is also possible to increase the noise immunity of the developed smart differential pressure sensor and provide an unparalleled combination of flexibility and integration of analog and digital functionality. Originality/value The use of PSoC technology in the developed smart differential pressure sensor has many indisputable advantages, as the size of the entire circuit can be minimized. As a result, the circuit has improved noise immunity. Accordingly, the procedure for debugging and changing the software of the electronics unit is simplified. These features make development and manufacturing cost effective.

Internal and external factors effect on the mobile pressure sensors’ performance

Sensor Review ◽  
2016 ◽  
Vol 36 (4) ◽  
pp. 405-413 ◽  
Author(s):  
Semih Dalgin ◽  
Ahmet Özgür Dogru
Keyword(s):  
Pressure Sensor ◽  
Mobile Applications ◽  
Pressure Sensors ◽  
External Factors ◽  
Sensor Data ◽  
High Tech ◽  
Internal Factors ◽  
Content Type ◽  
Internal And External Factors ◽  
Mems Pressure Sensors

Purpose The purpose of this study is to investigate the effect of internal and external factors on the accuracy and consistency of the data provided by mobile-embedded micro-electromechanical system (MEMS) pressure sensors based on smartphones currently in use. Design/methodology/approach For this purpose, sensor type and smartphone model have been regarded as internal factors, whereas temperature, location and usage habits have been considered as external factors. These factors have been investigated by examining data sets provided by sensors from 14 different smartphones. In this context, internal factors have been analyzed by implementing accuracy assessment processes for three different smartphone models, whereas external factors have been evaluated by analyzing the line charts which present timely pressure changes. Findings The study outlined that the sensor data at different sources have different characteristics due to the affecting parameters. Even if the pressure sensors are used under similar circumstances, data of these sensors have inconsistencies because of the sensor drift originated by internal factors. This study concluded that it was not applicable to provide a common correction coefficient for pressure sensor data of each smartphone model. Therefore, relative data (pressure differences) should be taken into consideration rather than absolute data (pressure values) when developing mobile applications using sensor data. Research limitations/implications Results of this study can be used as the guideline for developing mobile applications using MEMS pressure sensors. One of the main finding of this paper is promoting the use of relative data (pressure differences) rather than absolute data (pressure values) when developing mobile applications using smartphone-embedded sensor data. This significant result was proved by examinations applied with in the study and can be applied by future research studies. Originality/value Existing studies mostly evaluate the use of MEMS pressure sensor data obtained from limited number of smartphone models. As each smartphone model has a specific technology, factors affecting the sensor performances should be identified and analyzed precisely in terms of smartphone models for providing extensive results. In this study, five smartphone models were used fractionally. In this context, they were used for examining the common effects of the factors, and detailed accuracy assessments were applied by using two high-tech smartphones in the market.

MEMS piezoresistive pressure sensor with patterned thinning of diaphragm

2020 ◽  
Vol 37 (3) ◽  
pp. 147-153
Author(s):  
Zoheir Kordrostami ◽  
Kourosh Hassanli ◽  
Amir Akbarian
Keyword(s):  
Pressure Sensor ◽  
Design Methodology ◽  
Pressure Sensors ◽  
Mems Sensors ◽  
Sensors And Actuators ◽  
Content Type ◽  
Sensor Performance ◽  
Piezoresistive Pressure Sensor ◽  
Piezoelectric Pressure Sensor ◽  
First Time

Purpose The purpose of this study is to find a new design that can increase the sensitivity of the sensor without sacrificing the linearity. A novel and very efficient method for increasing the sensitivity of MEMS pressure sensor has been proposed for the first time. Rather than perforation, we propose patterned thinning of the diaphragm so that specific regions on it are thinner. This method allows the diaphragm to deflect more in response with regard to the pressure. The best excavation depth has been calculated and a pressure sensor with an optimal pattern for thinned regions has been designed. Compared to the perforated diaphragm with the same pattern, larger output voltage is achieved for the proposed sensor. Unlike the perforations that have to be near the edges of the diaphragm, it is possible for the thin regions to be placed around the center of the diaphragm. This significantly increases the sensitivity of the sensor. In our designation, we have reached a 60 per cent thinning (of the diaphragm area) while perforations larger than 40 per cent degrade the operation of the sensor. The proposed method is applicable to other MEMS sensors and actuators and improves their ultimate performance. Design/methodology/approach Instead of perforating the diaphragm, we propose a patterned thinning scheme which improves the sensor performance. Findings By using thinned regions on the diaphragm rather than perforations, the sensitivity of the sensor was improved. The simulation results show that the proposed design provides larger membrane deflections and higher output voltages compared to the pressure sensors with a normal or perforated diaphragm. Originality/value The proposed MEMS piezoelectric pressure sensor for the first time takes advantage of thinned diaphragm with optimum pattern of thinned regions, larger outputs and larger sensitivity compared with the simple or perforated diaphragm pressure sensors.

A capacitive sensor using resin thermoplastic elastomer and carbon fibers for monitoring pressure distribution

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guanzheng Wu ◽  
Siming Li ◽  
Jiayu Hu ◽  
Manchen Dong ◽  
Ke Dong ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fibers ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Thermoplastic Elastomer ◽  
Gauge Factor ◽  
Capacitive Pressure Sensor ◽  
Wearable Electronics ◽  
Content Type

Purpose This paper aims to study the working principle of the capacitive pressure sensor and explore the distribution of pressure acting on the surface of the capacitor. Herein, a kind of high sensitivity capacitive pressure sensor was prepared by overlaying carbon fibers (CFs) on the surfaces of the thermoplastic elastomer (TPE), the TPE with high elasticity is a dielectric elastomer for the sensor and the CFs with excellent electrical conductivity were designed as the conductor. Design/methodology/approach Due to the excellent mechanical properties and electrical conductivity of CFs, it was designed as the conductor layer for the TPE/CFs capacitive pressure sensor via laminating CFs on the surfaces of the columnar TPE. Then, a ‘#' type structure of the capacitive pressure sensor was designed and fabricated. Findings The ‘#' type of capacitive pressure sensor of TPE/CFs composite was obtained in high sensitivity with a gauge factor of 2.77. Furthermore, the change of gauge factor values of the sensor under 10 per cent of applied strains was repeated for 1,000 cycles, indicating its outstanding sensing stability. Moreover, the ‘#' type capacitive pressure sensor of TPE/CFs was consisted of several capacitor arrays via laminating CFs, which could detect the distribution of pressure. Research limitations/implications The TPE/CFs capacitive pressure sensor was easily fabricated with high sensitivity and quick responsiveness, which is desirably applied in wearable electronics, robots, medical devices, etc. Originality/value The outcome of this study will help to fabricate capacitive pressure sensors with high sensitivity and outstanding sensing stability.

An Overmolded Pressure Sensor Package Using an Ultrathick Photoresist Sacrificial Layer

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Lung-Tai Chen ◽  
Wood-Hi Cheng
Keyword(s):  
Pressure Sensor ◽  
Output Voltage ◽  
Sacrificial Layer ◽  
Pressure Sensors ◽  
Element Model ◽  
Silicon Membrane ◽  
Molding Process ◽  
Molding Compound ◽  
Voltage Drift ◽  
Sensor Package

This study presents a novel technique for an overmolded package of piezoresistive pressure sensors using an ultrathick photoresist sacrificial layer. A 150 μm photoresist block is placed just on the silicon membrane of the pressure sensor and removed after the molding transfer process. The removal of the photoresist block exposes and reserves a sensing channel in the overmolded pressure sensor package. Experimental observations reveal that the silicon membrane of the pressure sensor is completely free of any epoxy molding compound contamination after the transfer molding process. The effectiveness of the photoresist block in shielding the silicon membrane of the pressure sensor was confirmed. Experiment and finite element model results reveal that the packaged pressure sensor has similar sensing characteristics to those of an unpackaged pressure sensor at room temperature. However, the packaged pressure sensor exerts a thermomechanical stress on the silicon membrane of the pressure sensor, resulting in an undesired output voltage drift. Employing a proper package design can reduce the output voltage drift. The proposed packaging scheme has a small package volume and surface mount device compatible features, making it suitable for portable commercial devices.

scholarly journals Novel Flexible PVDF-TrFE and PVDF-TrFE/ZnO Pressure Sensor: Fabrication, Characterization and Investigation

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 602
Author(s):  
Mingran Liu ◽  
Yang Liu ◽  
Limin Zhou
Keyword(s):  
Pressure Sensor ◽  
Vinylidene Fluoride ◽  
Pressure Sensors ◽  
Weight Ratio ◽  
Composite Membranes ◽  
Annealing Process ◽  
Voltage Response ◽  
Electrical Signals ◽  
Β Phase ◽  
Phase Crystal

With the development of human healthcare devices, smart sensors, e-skins, and pressure sensors with outstanding sensitivity, flexibility, durability and biocompatibility have attracted more and more attention. In this paper, to develop a novel flexible pressure sensor with high sensitivity, different poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE)-based composite membranes were fabricated, characterized and tested. To improve the β-phase crystallinity and piezoelectricity of the membranes, and for the purpose of comparison, nano ZnO particles with different concentrations (99:1, 9:1 in a weight ratio of PVDF-TrFE to ZnO) were, respectively added into PVDF-TrFE polymer acting as a nucleating agent and dielectric material. To facilitate the formation of β-phase crystal, the membranes were fabricated by electrospinning method. After the electrospinning, an annealing process was conducted to the fabricated membranes to increase the size and content of β-phase crystal. Then, the fabricated PVDF-TrFE membranes, acting as the core sensing layer, were, respectively built into multiple prototype sensors in a sandwich structure. The sensitivity of the prototype sensors was tested by an auto-clicker. The stimulation of the auto-clicker on the prototype sensors generated electrical signals, and the electrical signals were collected by a self-built testing platform powered by LabVIEW. As a result, combining the addition of ZnO nanofillers and the annealing process, a highly sensitive pressure sensor was fabricated. The optimal peak-to-peak voltage response generated from the prototype sensor was 1.788 V which shows a 75% increase compared to that of the pristine PVDF-TrFE sensor. Furthermore, a human pulse waveform was captured by a prototype sensor which exhibits tremendous prospects for application in healthcare devices.

Micro-pressure sensor dynamic performance analysis

Sensor Review ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 367-373 ◽  
Author(s):  
Bian Tian ◽  
Yulong Zhao ◽  
Zhe Niu ◽  
Jiang Zhuangde
Keyword(s):  
Dynamic Characteristics ◽  
Pressure Sensor ◽  
Dynamic Pressure ◽  
Dynamic Performance ◽  
Pressure Sensors ◽  
Dynamic Responses ◽  
Content Type ◽  
Dynamic Performances ◽  
Traditional Structures ◽  
Dynamic Performance Analysis

Purpose – The purpose of this paper is to report on a piezoresistive pressure sensor for micro-pressure measurement with a cross-beam membrane (CBM) structure. This study analyzes the dynamic characteristics of the proposed device. Design/methodology/approach – This CBM sensor possesses high stiffness and sensitivity, measuring dynamic pressure more effectively in a high-frequency environment compared with other piezoresistive structures. The dynamic characteristics are derived using the finite element method to analyze the dynamic responses of the new structure, including natural frequency and lateral effect performances. The CBM dynamic performances are compared with traditional structures. Findings – The pressure sensor performance was evaluated, and the experimental results indicate that they all exhibit similar dynamic characteristics as the designed model. Compared with traditional structures such as the single island, the CBM proves to be superior in evaluating the dynamic performances of pressure sensors at high frequencies of > 30 kHz. Originality/value – Most studies of this micro pressure sensors attempt to promote the sensitivity or focus on the static performance of pressure sensor with micro gauge. This study is concerned with analyze the dynamic characterism of micro pressure sensor and compared with the traditional structures, that prove the CBM structure has stable dynamic performance and is a better option for measuring dynamic micro pressure in biomedical applications.

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