The future of product design utilising printed electronics

This paper addresses the teaching of emerging technologies to design students, using ‘printed electronics’ as an example as it recently became viable to mass manufacture and is ready for use in designs. Printed electronics is introduced as a disruptive technology, and approaches employed in knowledge transfer to industrial/product designers is reviewed. An overview of the technology is provided; the printing processes; material properties; a comparison with conventional electronics; and product examples are identified. Two case studies illustrate approaches for knowledge transfer to student designers. The assessment criteria and design outcomes from the case study projects are reviewed and future/new approaches proposed. The paper concludes that there is a need to develop a thorough knowledge transfer strategy for printed electronics to designers, informed by case studies and extending beyond simply showing examples of existing technology. This is necessary for future proofing both in technological advances and designing for the future

Human factors in the design of medical devices – approaches to meeting international standards in the European Union and USA

This paper focuses on the challenges of meeting agency requirements as it pertains to the application of human factors in the medical device development (MDD) process. Individual case studies of the design and development process for 18 medical device manufacturers located in the US and EU were analysed and compared using a multiple case study design. The results indicate that there are four main challenges in implementing international standards. These include a lack of direct access to users for the purposes of device development; a lack of understanding by users with regards to the impact of their feedback on the development process; contract formalities limiting user exchanges; and the attitude of clinical users directly impacting on the device developer's invitation to participate in the development processes. The barriers presented in this research have the potential to be resolved but only with greater commitment by both medical device users and developers

Meeting the expectation of industry: an integrated approach for the teaching of mechanics and electronics to design students

This paper examines the traditional engineering-based provision delivered to Product Design and Technology (B.Sc.) undergraduates at the Loughborough Design School and questions its relevancy against the increasing expectations of industry. The paper reviews final-year design projects to understand the level of transference of engineering-based knowledge into design practice and highlights areas of opportunity for improved teaching and learning. The paper discusses the development and implementation of an integrated approach to the teaching of Mechanics and Electronics to formalise and reinforce the key learning process of transference within the design context. The paper concludes with observations from the delivery of this integrated teaching and offers insights from student and academic perspectives for the further improvement of engineering-based teaching and learning

The future of product design utilising printed electronics

This paper addresses the teaching of emerging technologies to design students, using ‘printed electronics’ as an example as it recently became viable to mass manufacture and is ready for use in designs. Printed electronics is introduced as a disruptive technology, and approaches employed in knowledge transfer to industrial/product designers is reviewed. An overview of the technology is provided; the printing processes; material properties; a comparison with conventional electronics; and product examples are identified. Two case studies illustrate approaches for knowledge transfer to student designers. The assessment criteria and design outcomes from the case study projects are reviewed and future/new approaches proposed. The paper concludes that there is a need to develop a thorough knowledge transfer strategy for printed electronics to designers, informed by case studies and extending beyond simply showing examples of existing technology. This is necessary for future proofing both in technological advances and designing for the future

Printed electrodes for flexible, light-weight solid-state supercapacitors - a feasibility study

Purpose – The purpose of this paper is to report on the feasibility of the manufacture of printed rechargeable power sources incorporating, in the first instance, electrode structures from the previous study, and moving on to improved electrode structures fabricated, via flexographic printing, using commercially available inks. It has been shown previously that offset lithography, a common printing technique, can be used to make electrodes for energy storage devices such as primary cells. Design/methodology/approach – A pair of the original Ag/C electrodes, printed via offset lithography, were sandwiched together with a PVA-KOH gel electrolyte and then sealed. The resultant structures were characterised using electrochemical techniques and the performance as supercapacitors assessed. Following these studies, electrode structures of the same dimensions, consisting of two layers, a silver-based current collector covered with a high surface area carbon layer, were printed flexographically, using inks, on a melinex substrate. The characterisation and assessment of these structures, as supercapacitors, was determined. Findings – It was found that the supercapacitors constructed using the offset lithographic electrodes exhibited a capacitance of 0.72 mF/cm2 and had an equivalent series resistance of 3.96 Ω. The structures fabricated via flexography exhibited a capacitance of 4 mF/cm2 and had an equivalent series resistance of 1.25 Ω The supercapacitor structures were subjected to bending and rolling tests to determine device performance under deformation and stress. It was found that supercapacitor performance was not significantly reduced by bending or rolling. Originality/value – This paper provides insight into the use of printed silver/carbon electrodes within supercapacitor structures and compares the performance of devices fabricated using inks for offset lithographic printing presses and those made using commercially available inks for flexographic printing. The potential viability of such structures for low-end and cheap energy storage devices is demonstrated

Humidity sensing properties of transparent sputter-coated indium-tin oxide and printed polymer structures

The humidity sensing properties of sputter coated indium tin oxide (ITO) and printed dielectric structures were tested for samples with sheet resistances ranging from 10Ω/sq to 50Ω/sq. ITO/Polymer composite sensors were fabricated to form a parallel plate capacitive based humidity sensor that could detect relative humidity within a tested range of 5%to 95%. The sensors were most stable and gave a linear response between 5 and 75% relative humidity. The capacitive sensors were characterized, using a range of techniques, to establish their capability and performance as humidity monitors. Response time of the humidity sensors was measured to be an average of 31.5 seconds and recovery time was measured at an average of 31 seconds in capacitive mode. Complex impedance spectroscopy was used to determine the mechanism of action for the sensors which was found to be both diffusion of water molecules into the dielectric layer and an increase of ionic conductivity within the dielectric layer. Stability of the humidity sensors were tested at three different humidity levels over 7 days and sensors were found to be stable or follow a predictable change for this time span

Development and characterisation of lithographically printed voltaic cells

This paper reports progress in thefabrication ofvoltaic cells and batteries via offset lithographic printing. Successful design and manufacture oflithographically printed voltaic cells wouldfacilitate the integration of printedpassive components, interconnects and display elements for disposable electronics in low-volume, low weight circuits and systems. The Conductive Lithographic Film (CLF) printing process was developed by Brunel University to fabricate circuit interconnect and various passive components at high speed and low cost. Afeasibility study, investigatingprinted cells based on Zinc-Carbon electrochemistry, is described. This has resulted in the production ofa printed battery able to power a microcontroller-driven LED display system for more than three hours. Further work seeks to improve cell capacity, address manufacturing process issues, and characterise the structures in more detail

Lithographically printed voltaic cells – a feasibility study

It has been shown that circuit interconnects and various passive components can be fabricated on a variety of flexible substrates using the offset lithographic process. This paper reports on a feasibility study investigating the manufacture of voltaic cells deposited via offset lithography. The Leclanche´ cell, an established battery chemistry, was chosen as an appropriate technology for adaptation to the offset lithographic process. Development of inks with appropriate rheological properties for lithographic printing was undertaken. Zinc and carbon electrodes were fabricated with silver-based current collectors. Electrolyte composition was investigated along with separator materials. Zinc and carbon-based inks have been produced which result in deposited material appropriate for use as electrodes. A separator material soaked in electrolyte has been combined with these electrode structures and an MnO2 paste to form a voltaic cell. A printed battery, made up of these voltaic cells, with a capacity greater than 8 mAh at 6 V has been produced. The fabrication of voltaic cells via offset lithography facilitates the production of electronic systems with power sources provided by the same printing process. This paper provides information of interest to all those involved in the developing industry of printed and flexible electronics

Experimental design to optimise electrical performance of strip supercapacitors

Strip shaped electric double-layer supercapacitors (EDLCs) using activated carbon as the electrode material have been successfully fabricated and optimised. Their electrochemical characteristics were studied using a VersaSTAT 3 electrochemical workstation. The experimental design software, JMP™, was used to optimise the main parameters of supercapacitors in order to maximise the electrical performance. Simultaneously, the relationship between the electrical performance and the key manufacturing factors of the EDLCs, including the binder content, the electrolyte concentration and the thickness of electrode materials was studied and discussed

Flexible, all metal-oxide capacitors for printed electronics

In this research the use of micron and nanoparticle metal oxide materials for conductive and dielectric screen printing inks were investigated. Screen printed parallel plate capacitors were fabricated to research the applications of these inks. Conductive, micron-particle indium tin oxide (ITO) screen printing inks were formulated for the conductive plates. A dielectric, nanoparticle aluminium oxide (Al2O3) ink was formulated for the dielectric barrier. Capacitors of varying sizes (1cm2 – 9cm2 ) were printed onto flexible polyethylene terephthalate (PET) sheets. The effect of dielectric layer thickness was investigated to find the optimal fabrication process. Impedance analysis was performed on the capacitors to characterise both the performance of the capacitors and the dielectric ink. Analysis of the capacitors was also performed under flex (up to 30% strain) to investigate the effect of bending on the electronic properties. The capacitors were found to be highly stable under bending enabling their use in flexible printed electronics applications