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ment vendor Heraeus. One of the reasons might be the fact that this technology yet has to develop an n-semiconductor. Thus, transistors comparable to conventional ones with their pnp or npn layer sequence are not (yet) possible. Another problem is the lack of standardisation. “We are aware of this challenge”, Mildner said. Upon initiative from Asian market participants, a Printing equipment and organic electronics technology company Novacentrix showed what perhaps will become a fashion trend in the coming years: T-shirts with integrated electric conductors and LEDs. standardisation process has been launched. “The process is on its way.” Despite the lack of a p-semiconducting material, the industry has seen progress in the field of materials over the past couple of years. For instance, metallic inks increasingly are complementing the spectrum or organic materials. Cynora GmbH was displaying its emitter materials and OLED demonstrators. The company, based in Bruchsal (Germany) is said to be pioneer in materials that make expensive and exotic metals like platinum and iridium redundant and enable cost-effective printing processes. Stick a PUF to your hardware The Fraunhofer Institute for Applied and Integrated Security (AISEC) is developing a very versatile and flexible form of Physically Unclonable Function (PUF), one that can wrap an entire circuit board to secure it from physical attacks. The foil-based solution consists of patterned metal electrodes embedded into a polymer film with a self-adhesive backing. The electrodes are connected to the board to be protected and special read-out software IP running on the board’s controller can extract the PUF from the film as it has been wrapped around or stuck to the board. Try to remove the PUF sticker, stretch it, pinch it to probe through it, scratch it or unseal it and the PUF will be altered. By detecting that change, the circuit board will be able to take any counter-measure it will have been programmed for, for example sending an alert message and disabling itself at run-time, or wiping out all of its embedded software. Showing a demo at Embedded World, Fraunhofer AISEC’s head researcher on the so-called PEP project (Protecting Electronic Products, maybe with a pun intended on Polyethylene Plastics), Sven Plaga didn’t want to say too much about the internals of the film. “Now we are exploring electrode patterns of different shapes and complexities as well as correction algorithms to ensure the PUF’s stability over time and across different temperatures as the film could shrink or expand”. For the researchers, it is all about finding the right trade-off between PUF complexity and stability, but they are investigating different sizes and they expect the PUF foil to be produced cheaply in a roll-to-roll printing process. “The advantage over silicon-based PUFs is that one foil could protect an entire board or system, it is also much cheaper and simpler to implement”, he added, saying such a PUF sticker may be commercialized within the next two to three years. Like at the booth demonstration, the foil could even extend outside an electronic enclosure or be part of a seal to detect its opening. In that case the plastic PUF provides not only a unique key for securing on-board communications, it can also serve for early external tamper detection (maybe to launch different and more subtle pre-programmed routines based on its status, such as fake board operation). Add capacitive touch to a panel with a flexible, rollable film Zytronic has applied its projected capacitive touch sensing technology to the form factor of a rollable and extremely flexible touch film – complementing its range of glass touch sensors. The flexible film uses the company’s Multi-touch Projected Capacitive Technology (MPCT), and is aimed at retail and other digital signage applications that require large, eye-catching interactive displays. The film gives designers the option of creating their own touch screen displays by laminating the film on to the rear of a transparent substrate – such as a shop window – and combining it with a projector or LCD. Available in sizes up to 85 inches (2.15m), the polyester touch foils can be deployed in semi-permanent and permanent applications when correctly laminated to a suitable substrate. Used in conjunction with Zytronic’s ZXY200 and ZXY300 multi-touch controllers, the touch foils are capable of detecting up to 40 simultaneous touch points through glass thicknesses of 10 mm. This results in a cost effective interactive solution with, the company says, class-leading touch performance. The thinner construction of the new ZYFILM touch foils mean that they can be packed in tubes when shipped in small quantities – minimising transportation costs. When mounted on the rear surface of a protective substrate, the projected capacitive sensor is well protected and resilient to public use. This, coupled with its one time calibration and absence of drift, translates into high levels of reliability. Zytronic www.zytronic.co.uk www.electronics-eetimes.com Electronic Engineering Times Europe March 2015 45


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