Gareth I. Hay

Lithographically printed voltaic cells – a feasibility study

Purpose – 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.Design/methodology/approach – 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.Findings – 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 ...

Printed thermocouple devices

A novel process for the fabrication of thermocouples using thick-film techniques has been developed. Thermoelectric reactions of 22 /spl mu/V//spl deg/C per couple have been observed which are comparable to those of conventional thermocouples. The paper outlines the potential for a rapid, low-cost, low temperature manufacturing solution for the production of electrical temperature sensors.

Design and manufacture of surface textures on gun cartridge cases to trap DNA material

Abstract US and Australian work has shown that the effectiveness of extracting deoxyribonucleic acid (DNA) from standard gun cartridges is low and so analysis costs are high (www.cci.gov/Reference/LpDNACtg_files). The presence of greater than 1 ng of trapped bio-material would increase the success rates of DNA profiling and facilitate cheaper DNA analysis. The aim of this work is to increase the amount of recoverable DNA from a gun user deposited on fired cartridges, using microtextured surfaces as DNA receptors. Success would increase the probability of identifying perpetrators of gun crime through DNA matching. Various textures have been applied to flat surfaces of cartridge case material and the effects of those surface textures on trapping skin materials have been evaluated. In addition to treated/patterned surfaces, standard emery abrasive paper was adopted as a control medium. From the different surfaces tested, the emery abrasive paper was found to be most effective at trapping skin debris. Rough surfaces with pyramid textures, which are similar to features on emery paper, were subsequently manufactured on cartridge rims by a standard knurling process. Scratch tests were carried out to simulate the process of handling and loading these cartridges during the use of firearms. DNA test results of the knurled cartridges after firing, showed a high success rate of DNA profiling and high matching percentage to the donors DNA profile.

Flexible dot-matrix display manufacture by offset lithography

Novel thermochromic graphic displays manufactured by printing thermochromic ink films in conjunction with conductive lithographic films (CLFs) are presented. Work in formulating lithographic printing inks is described. The properties of the deposited ink films and demonstration display structures employing these materials are discussed. These low-cost printed structures could be incorporated in the manufacture of electronic systems with integrated printed power sources affording environmental benefits when compared with conventional manufacturing techniques.

Electroluminescent light sources via soft lithography

Purpose – Microcontact printing is a process used to print high‐resolution protein arrays for biosensors. The paper aims to investigate using these techniques to print electrically conductive fine line structures for electroluminescent (E/L) light sources.Design/methodology/approach – The viability of using microcontact printing as a process for electronics fabrication is investigated. Polydimethylsiloxane stamps inked with alkanethiol compounds form self‐assembled monolayers on substrate surfaces, acting as the resist to subsequent etching processes. The printed lines are characterized with regard to their performance as high‐electric field generators in electroluminescent displays.Findings – It has been demonstrated that microcontact printing is a cheap, repeatable process for fabricating electronic devices. The results demonstrate the viability of the process to fabricate electric field generator structures for E/L light sources with reduced driving voltages.Originality/value – The paper demonstrates t...

Development and Characterisation of Lithographically Printed Voltaic Cells

This paper reports progress in the fabrication of voltaic cells and batteries via offset lithographic printing. Successful design and manufacture of lithographically printed voltaic cells would facilitate the integration of printed passive 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. A feasibility study, investigating printed cells based on zinc-carbon electrochemistry, is described. This has resulted in the production of a 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

A time–strain monitoring system fabricated via offset lithographic printing

This paper reports progress in the development of strain sensors fabricated using the conductive lithographic film (CLF) printing process. Strain sensitive structures printed via an unmodified offset lithographic printing press using a silver-loaded conductive ink have been deposited concurrently with circuit interconnect, to form an electronic smart packaging system. A system populated with surface mount technology (SMT) components has proven successful in interpreting and logging deformation incidences subjected to a package during testing. It is proposed that with further development such a system could be printed synchronously with packaging graphics using a single printing process to form an integrated time–strain monitoring system.