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Article
Publication date: 3 February 2020

Youzhi Zhang, Zhengkang Lin, Xiaojun You, Xingping Huang, Jinhua Ye and Haibin Wu

This paper aims to report a flexible position-sensitive sensor that can be applied as large-area electronic skin over the stiff media.

Abstract

Purpose

This paper aims to report a flexible position-sensitive sensor that can be applied as large-area electronic skin over the stiff media.

Design/methodology/approach

The sensor uses a whole piezoresistive film as a touch sensing area. By alternately constructing two uniform electric fields with orthogonal directions in the piezoresistive film, the local changes in conductivity caused by touch can be projected to the boundary along the equipotential line under the constraint of electric field. Based on the change of boundary potential in the two uniform electric fields, it can be easy to determine the position of the contact area in the piezoresistive film.

Findings

Experiment results show the proposed tactile sensor is capable of detecting the contact position and classifying the contact force in real-time based on the changes of the potential differences on the boundary of the sensor.

Practical implications

The application example of using the sensor sample as a controller in shooting game is presented in this paper. It shows that the sensor has excellent touch sensing performance.

Originality/value

In this paper, a position-sensitive electronic skin is proposed. The experiment results show that the sensor has great application prospects in the field of interactive tactile sensing.

Details

Sensor Review, vol. 40 no. 1
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 9 September 2013

Pradeep Kumar Rathore, Pratyush Varshney, Sunil Prasad and B.S. Panwar

The purpose of this paper is to use finite element method for optimizing the membrane type double cavity vacuum sealed structure for the best achievable sensitivity in a…

Abstract

Purpose

The purpose of this paper is to use finite element method for optimizing the membrane type double cavity vacuum sealed structure for the best achievable sensitivity in a piezoresistive absolute pressure sensor and its validation using a standard complementary metal oxide semiconductor (CMOS) process.

Design/methodology/approach

A double cavity vacuum sealed piezoresistive absolute pressure sensor has been simulated and optimized for its performance and an analytical model describing the behaviour of the sensor has been described. The 1×1 mm sensor chip has two membrane type 100×30×1.7 μm diaphragms consisting of composite layers of plasma enhanced chemical vapour deposition (PECVD) of silicon nitride (Si3N4) and silicon dioxide (SiO2) each hanging over 21 μm deep rectangular cavity. Potassium hydroxide (KOH) based anisotropic etching of single crystal silicon using front side lateral etching technology is used for the fabrication of the sensor. The electrical readout circuitry uses 318 Ω boron diffused low pressure vapour chemical vapour deposition (LPCVD) of polysilicon resistors arranged in the Wheatstone half bridge configuration. The sensing structure is simulated and optimized using COMSOL Multiphysics.

Findings

Front-side lateral etching technology has been successfully used for the fabrication of double cavity absolute pressure sensor. A good agreement with the fabricated device for the chosen location of the piezoresistors through simulation has been predicted. The measured pressure sensitivity of two tested pressure sensors is 12.63 and 12.46 mV/MPa, and simulated pressure sensitivity is found to be 12.9 mV/MPa for pressure range of 0 to 0.5 MPa. The location of the piezoresistor has also been optimized using the simulation tools for enhancing the sensor sensitivity to 62.14 mV/MPa. The pressure sensitivity is further enhanced to 92 mV/MPa by increasing the width of the diaphragm to 35 μm.

Originality/value

The simulated and measured pressure sensitivities of the double cavity pressure sensor are in close agreement. Sevenfold enhancement in the pressure sensitivity of the optimized sensing structure has been observed. The proposed front-side lateral etching technology can be adopted for making membrane type diaphragms hanging over vacuum sealed micro-cavities for high sensitivity pressure sensing applications.

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Article
Publication date: 8 November 2019

Dinesh Ramkrushna Rotake, Anand D. Darji and Nitin S. Kale

This paper aims to propose a new microfluidic portable experimental platform for quick detection of heavy metal ions (HMIs) in picomolar range. The experimental setup uses…

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Abstract

Purpose

This paper aims to propose a new microfluidic portable experimental platform for quick detection of heavy metal ions (HMIs) in picomolar range. The experimental setup uses a microfabricated piezoresistive sensor (MPS) array of eight cantilevers with ion-selective self-assembled monolayer's (SAM).

Design/methodology/approach

Most of the components used in this experimental setup are battery operated and, hence, portable to perform the on-field experiments. HMIs (antigen) and thiol-based SAM (antibody) interaction start bending the microcantilever. This results in a change of resistance, which is directly proportional to the surface stress produced due to the mass of targeted HMIs. The authors have used Cysteamine and 4-Mercaptobenzoic acid as a thiol for creating SAM to test the sensitivity and identify the suitable thiol. Some of the cantilevers are blocked using acetyl chloride to use as a reference for error detection.

Findings

The portable experimental platform achieves very small detection time of 10-25 min with a lower limit of detection (LOD) 0.762 ng (6.05 pM) for SAM of Cysteamine and 4-Mercaptobenzoic acid to detect Mn2+ ions. This technique has excellent potential and capability to selectively detect Hg2+ ions as low as 2.43 pM/mL using SAM of Homocysteine (Hcys)-Pyridinedicarboxylic acid (PDCA).

Research limitations/implications

As microcantilever is very thin and fragile, it is challenging to apply a surface coating to have selective detection using Nanadispenser. Some of the cantilevers get broken during this process.

Originality/value

The excessive use and commercialization of NPs are quickly expanding their toxic impact on health and the environment. Also, LOD is limited to nanomolar range. The proposed method used the combination of thin-film, NPs, and MEMS-based technology to overcome the limitation of NPs-based technique and have picomolar range of HMIs detection.

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Article
Publication date: 15 June 2015

Yan Liu, Hai Wang, Hongbo Qin and Yongqiang Xie

– This paper aims to provide a focused review on the geometrical designs for performance enhancement of piezoresistive microaccelerometers.

Abstract

Purpose

This paper aims to provide a focused review on the geometrical designs for performance enhancement of piezoresistive microaccelerometers.

Design/methodology/approach

By analyzing working principle and conventional geometries, the improved research proposals are sorted into three groups in terms of their anticipated objectives, including sensitivity, resonant frequency and cross-axis sensitivity. Accessible methods are outlined and their merits and demerits are described.

Findings

Novel geometries obviously enhance the performance of accelerometers, and the efficacy can be further elevated by newer materials and fabrication processes.

Research limitations/implications

This paper mainly focused on the improved geometrical designs for sensitivity, resonant frequency and cross-axis sensitivity. Other performance parameters or design schemes are not included in this paper.

Originality/value

This paper generalizes the available geometries and methods for the enhancement of sensitivity, resonant frequency and cross-axis sensitivity in piezoresistive accelerometers design.

Details

Sensor Review, vol. 35 no. 3
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 1 February 1986

M. Prudenziati and B. Morten

The paper gives a review of the present knowledge of the piezoresistive properties of thick‐film resistors (TFRs) and shows how they have been exploited for the…

Abstract

The paper gives a review of the present knowledge of the piezoresistive properties of thick‐film resistors (TFRs) and shows how they have been exploited for the implementation of strain‐related physical‐quantities transducers. Two types of device are described in some detail. These achievements were made possible by a proper choice of resistive and conductive pastes and their firing conditions, since only in this case useful piezoresistive properties can be achieved that make TFR strain gauges competitive with metal and semiconductive materials. After examining some correlations between gauge factors, composition and structure of TFRs, new data are presented showing how the strain sensitivities may be changed by varying the peak firing temperature, dwell time and the nature of the chemical elements which diffuse from terminations in the films.

Details

Microelectronics International, vol. 3 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 30 July 2020

Dinesh Ramkrushna Rotake, Anand Darji and Nitin S. Kale

This paper aims to report an insightful portable microfluidic system for rapid and selective sensing of Hg2+ in the picomolar (pM) concentration using…

Abstract

Purpose

This paper aims to report an insightful portable microfluidic system for rapid and selective sensing of Hg2+ in the picomolar (pM) concentration using microcantilever-based piezoresistive sensor. The detection time for various laboratory-based techniques is generally 12–24 h. The majority of modules used in the proposed platform are battery oriented; therefore, they are portable and handy to carry-out on-field investigations.

Design/methodology/approach

In this study, the authors have incorporated the benefit of three technologies, i.e. thin-film, nanoparticles (NPs) and micro-electro-mechanical systems, to selectively capture the Hg2+ at the pM concentration. The morphology and topography of the proposed sensor are characterized using field emission scanning electron microscopy and verification of the experimental results using energy dispersive X-ray.

Findings

The proposed portable microfluidic system is able to perform the detection in 5 min with a limit of detection (LOD) of 0.163 ng (0.81 pM/mL) for Hg2+, which perfectly describes its excellent performance over other reported techniques.

Research limitations/implications

A microcantilever-based technology is perfect for on-site detection, and a LOD of 0.163 ng (0.81 pM/mL) is outstanding compared to other techniques, but the fabrication of microcantilever sensor is complex.

Originality/value

Many researchers used NPs for heavy metal ions sensing, but the excess usage and industrialization of NPs are rapidly expanding harmful consequences on the human life and nature. Also, the LOD of the NPs-based method is limited to nanomolar concentration. The suggested microfluidic system used the benefit of thin-film and microcantilever devices to provide advancement over the NPs-based approach and it has a selective sensing in pM concentration.

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Article
Publication date: 6 March 2019

Rafiu King Raji, Xuhong Miao, Shu Zhang, Yutian Li, Ailan Wan and Charles Frimpong

The use of conductive yarns or wires to design and construct fabric-based strain sensors is a research area that is gaining much attention in recent years. This is based…

Abstract

Purpose

The use of conductive yarns or wires to design and construct fabric-based strain sensors is a research area that is gaining much attention in recent years. This is based on a profound theory that conductive yarns will have a variation in resistance if subjected to tension. What is not clear is to which types of conductive yarns are most suited to delivering the right sensitivity. The purpose of this paper is to look at strain sensors knitted with conductive composite and coated yarns which include core spun, blended, coated and commingled yarns. The conductive components are stainless steel and silver coating respectively with polyester as the nonconductive part. Using Stoll CMS 530 flat knitting machine, five samples each were knitted with the mentioned yarn categories using 1×1 rib structure. Sensitivity tests were carried out on the samples. Piezoresistive response of the samples reveals that yarns with heterogeneous external structures showed both an increase and a decrease in resistance, whereas those with homogenous structures responded linearly to stress. Stainless steel based yarns also had higher piezoresistive range compared to the silver-coated ones. However, comparing all the knitted samples, silver-coated yarn (SCY) proved to be more suitable for strain sensor as its response to tension was unidirectional with an appreciable range of change in resistance.

Design/methodology/approach

Conductive composite yarns, namely, core spun yarn (CSY1), core spun yarn (CSY2), silver-coated blended yarn (SCBY), staple fiber blended yarn (SFBY) and commingled yarn (CMY) were sourced based on specifications and used to knit strain sensor samples. Electro-mechanical properties were investigated by stretching on a fabric tensile machine to ascertain their suitability for a textile strain sensor.

Findings

In order to generate usable signal for a strain sensor for a conductive yarn, it must have persistent and consistent conductive links, both externally and internally. In the case of composite yarns such as SFBY, SCBY and CMY where there were no consistent alignment and inter-yarn contact, resistance change fluctuated. Among all six different types of yarns used, SCY presented the most suitable result as its response to tension was unidirectional with an appreciable range of change in resistance.

Originality/value

This is an original research carried out by the authors who studied the electro-mechanical properties of some composite conductive yarns that have not been studied before in textile strain sensor research. Detailed research methods, results and interpretation of the results have thus been presented.

Details

International Journal of Clothing Science and Technology, vol. 31 no. 2
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 1 August 1999

Reiner W. Kühl

A very common method to predict the reliability of components soldered on printed circuit board (PCB) or substrates is by bending tests and temperature cycle tests, for…

Abstract

A very common method to predict the reliability of components soldered on printed circuit board (PCB) or substrates is by bending tests and temperature cycle tests, for instance between ‐55°C and 125°C (up to 2,000 cycles at 1h cycle period). Sensitive SMD constructions such as chips with ball grid array mounting or multilayer chip capacitors (MLCC) are often a major issue due to their “flex cracking” problems. This paper describes the real behaviour of deformation at temperature cycling and PCB bending of chip components (body size 0603). By using the piezoresistive effect in thick film resistors the effects of stress on the alumina body can be determined and described for the whole temperature range of interest. The complete system of component, PCB/substrate and solder joint will be discussed and different influences will be isolated. It will be shown that CTE‐matching of the component and substrate does not lead to an optimum situation. The influence of the solder joint plays an important part. Optimization potentials and design rules for the whole system will be given. The basis of this paper is a quite unusual “measurement tool” the effect of piezoresistivity. The investigation into that phenomenon will be described very thoroughly first.

Details

Soldering & Surface Mount Technology, vol. 11 no. 2
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 7 June 2019

Janusz Borecki, Aneta Araźna, Kamil Janeczek, Jerzy Kalenik, Michał Kalenik, Wojciech Stęplewski and Rafał Tarakowski

Nowadays, using of material properties for monitoring of phenomena occurring in the surrounding environment is very desirable. Taking into account the dynamic development…

Abstract

Purpose

Nowadays, using of material properties for monitoring of phenomena occurring in the surrounding environment is very desirable. Taking into account the dynamic development of Internet of Things and the technological development of printed electronics, research into the using of printed electronic components for sensor applications can be one of the most prominent directions of searching for new innovative solutions. Among others, it is possible to apply them to produce the strain gauges, as well as for construction of advanced sensors for medical applications. The goal of this paper is to present the possibilities and using different constructions of embedded polymer thick-film resistors as the sensors of tension or strain.

Design/methodology/approach

The investigations were based on the polymer thick-film resistors made of carbon or carbon–silver inks printed on copper pads made on FR-4 material on two sides. The longitudinal samples laminated with resin-coated copper foil material and without lamination were bent on a strength machine. During the tests, the resistors depending on their placement were stretched or compressed. Some of the samples were also tested under high pressure. Under the influence of applied stresses, there was a reversible change in electrical resistance, which was monitored.

Findings

The study showed that the polymer thick-film resistors are characterized by a measurable piezoresistive effect. By analyzing the value of the observed resistance changes, a magnitude of strain or pressure can be worked out. During the bending, the piezoresistive effect depends on the location and orientation of the resistor. After stopping of the mechanical strains, the electrical resistance of the resistive elements does not return exactly to the initial value. This is probably related to the substrate material and the resistive paste composition. The results are very promising and further research will be done.

Originality/value

The results provided information about the piezoresistive effect of polymer thick-film resistors printed on the deformable substrate which could be interesting for engineers involved in printed sensor development dedicated for different fields of application. This phenomenon can be used to manufacturing cheap and uncomplicated sensors to monitor deformation. There are several aspects to be solved, but with the use of new types of resistive pastes and substrates, there is a potential possibility of using such resistors as sensors.

Details

Circuit World, vol. 45 no. 1
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 14 September 2010

Bian Tian, Yulong Zhao and Zhuangde Jiang

The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.

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Abstract

Purpose

The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.

Design/methodology/approach

A kind of novel piezoresistive micro‐pressure sensor with a cross‐beam membrane (CBM) structure is designed based on the silicon substrate. Through analyzing the stress distribution of the new structure by finite element method, the model of structure is established and compared with traditional structures. The fabrication is operated on silicon wafer, which applies the technology of anisotropy chemical etching and inductively coupled plasma.

Findings

Compared to the traditional C‐ and E‐type structures, this new CBM structure has the advantages of low nonlinearity and high sensitivities by the cross‐beam on the membrane, which cause the stress is more concentrated in sensitive area and the deflections that relate to the linearity are decreased.

Originality/value

The paper provides the first empirical reports on the new piezoresistive structure for the pressure measurement by fabricating a cross‐beam on the membrane and resolving the conflict of nonlinearity and sensitivity of the piezoresistive sensors.

Details

Sensor Review, vol. 30 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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