Reading time ( words)
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The <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Institute of Circuit Technology held its Annual Symposium at the National Physical Laboratory (NPL) on 4th July. The theme was Printed Electronics and the day began with an introduction to NPL by Dr Chris Hunt. Chris stated that the NPL was the UK's national metrology centre and the place where much work was done to characterise materials. He highlighted work at NPL that was pertinent to the ICT. This included high reliability lead-free electronics, coatings technology and sustainability. NPL was also the Node for Electronics Assembly Technology (NEAT).
The first main presentation was from Dr Steve Jones of Printed Electronics and he discussed opportunities for printed electronics within Europe. Printed electronics would enable electronics to continue to be made in Europe. The different printing techniques were then reviewed. Most work was focussed on ink jet printing (IJP) where there was the possibility to produce one offs, prototype batches and in high volume. IJP offered the advantages of modest capital cost, small equipment footprints and low running costs. Digital and printed electronics could have wide applicability in a market that was becoming even more commodicised.
Mike Johnson of Conductive Ink Technology (CIT) then reviewed the different ink jet print heads available and how they varied between suppliers. CIT had taken a pragmatic approach to ink jet printing and their objective was the direct writing of conductors onto non-porous substrates. CIT had a low temperature process in which a catalytic ink was printed on a substrate and UV cured. The catalytic deposit could be used to initiate deposition of copper, silver, gold, nickel and cobalt. The process used standard industrial print heads and could produce 50 micron lines and spaces.
David Woodley of Technograph then gave a presentation on the production of advanced electronics for demanding applications beginning with an overview of the evolution of the printed circuit board. David described some of the high reliability applications for which his company manufactured products. Technograph were also working on various MEMS devices and had produced other types of assemblies for the Eurofighter and the Airbus A380.
The next paper was given jointly by Professor David Harrison and Darren Southee of BrunelUniversity. Brunel had a history of work on printing conductors onto novel polymer paper substrates using offset lithography. David gave an overview of how offset lithography worked. The aim of Brunel's work was more sustainable electronics via integration of low cost displays and power sources using printing processes. Darren then described work to extend lithographic printing to deposition of zinc carbon cells. A process had been developed and work was currently focussed on increasing the cell capacity.
The afternoon session commenced with a presentation by Rob Haslett of Patterning Technologies Ltd (PTL). After describing the benefits of ink jet, which included price, flexibility, rapid response and the fact that it was digital, he focussed on PTL's work to develop the direct printing of etch resist masks. A machine had built with an optical system that enabled double-sided printing and a lower cost machine had also been developed for ident printing. Potential future applications such as the deposition of bioactive layers, solar cell structures and micro lenses were discussed.
The final presentation was given by Chris Williams of the UK Displays and Lighting Knowledge Transfer Network. Chris emphasised where there really were applications for digital and printed electronics and also where the technology would never compete. The printing of discrete transistors over large surface areas for display applications was one area where printing offered opportunities.
Overall, this was a very interesting symposium that addressed a subject of growing importance. The ICT is to be congratulated for organising such a useful event and the choice of venue added to the overall quality.