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EETE DECEMBER 2012

DESIGN & PRODUCTS DISPLAYS & INTERFACES Applying 10-point multi-touch functionality to large curved surfaces By Ian Crosby WIth more sophIstICated human machine interfaces (hmIs) now being implemented in public use, retail digital sig- nage, leisure and industrial environments, multi-touch operation is proving highly desirable beyond the consumer electronics arena. the recognition of complex gestures can enhance the user experience or allows the collaboration of multiple opera- tives at once. In a growing proportion of applications, such functionalities could go beyond the confines of two dimensions to enable more ergonomic designs. Fig. 2: Microsoft’s Spatial Desk. all the different aspects of multi-touch, large active area and a curved surface arrangement into a hmI has been very challeng- ing. standard p-cap multi-touch solutions, such as those which are based on indium tin oxide (Ito) depositions, will not be as suited to curved surface application due to question marks Fig. 1: Both Samsung’s Nexus S and Nokia’s N9 smartphones being raised on their reliability. this is because the sputtering of Ito coatings and the printed metallic inks used in these sensors have curved touch surfaces. tend to be very brittle. If the conductive tracks become cracked, Figure 1 shows the use of curved multi-touch surfaces in the then the touch sensor will no longer be operational. portable consumer space, with the latest smartphone models by leading brands sporting them. potentially, curved touch In response to this issue touch sensor manufacturer Zytronic surfaces which are convex in nature can be integrated into next has developed an innovative way to implement its highly rugged generation games consoles, so that players will be able to ap- projected Capacitive technology (pCt) touchscreen solutions ply interactive ‘spinning reel’ movements. meanwhile concave onto large curved surfaces along one axis. the company has touch surfaces will permit several angled screens to be merged already produced large format novel shaped touch surfaces – together to form a seamless hmI. see figure 2 – where a single continuous touch surface covers multiple displays. microsoft’s spatial desk has been built on this For some time now, touch surfaces employing projective technology, adding the multi-touch capability into the mix. capacitance (p-cap) technology have been multi-touch enabled, and more recently this feature has made an appearance in larg- First, the glass designed to make up the touch surface is cut er form factor deployments. however, being able to combine to the specified size, edge finished and then heated to approxi- mately 635 °C until it reaches its softening point. at this stage, Ian Crosby is sales & marketing director for Zytronic - a curvature can be induced using the glass’ own weight. the www.zytronic.co.uk temperature profile and the time period that it needs to stay at 22 Electronic Engineering Times Europe December 2012 www.electronics-eetimes.com


EETE DECEMBER 2012
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