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EETE JAN 2015

Flexible multi-touch printed sensors ready ahead of screens By Julien Happich UK start -up R&D CORE has just announced a fully flexible touch screen sensor technology to work with Plastic Logic’s flexible display. In collaboration with printed electronics pioneer Plastic Logic, the company will further develop and finalise its flexible touch screen sensor technology for flexible displays. Dubbed Digital Resistive Area Sensing (DRAS) , the flexible touch screen sensor consists of printed patterns of conductive ink on two polyester substrates laminated together, with wiring patterns crossing at 90º. The touch sensor uses a four-wire sensing circuit elaborated in-house that can be read out by any MCU using the company’s proprietary algorithms. The sensor is said to overcome capacitive touch screen limitations including breakage, accidental use, moisture and an inability to operate when wearing insulating materials such as gloves. During a phone interview with EETimes Europe, R&D CORE Ltd’s CEO Thomas Papakostas didn’t want to explicit further the technology, saying that patents are pending and that the actual touch-sensor reading circuitry and scanning procedure are part of the company’s key IP. “We have designed the sensor’s printed circuits in a such a way that they work with any type of conductive inks available on the market”, told us Papakostas, “not only can we scan multiple touch-points at the same time, we can also scan the contact area and measure the applied force up to approximately a kilogram”. Force sensing is based on experimental data from the laminate’s deformation and resistive response. “We have prototyped our flexible sensor behind a flexible screen from Plastic Logic and it just works as a charm”, said Papakostas, hinting at the limitations of too brittle ITO solutions. “The touch sensor still worked when the display was flexed back and forth or rolled up to a diameter of around 4cm”. According to Papakostas, the sensor can also be made as large as the application requires without increasing the complexity of the hardware interface and without compromising the sensor performance. Although the company wants to grab the nascent flexible display market with its DRAS technology, in the short term it expects more revenue from conformable touch-interfaces including white goods and consumer electronics or large scale interactive touch-surfaces. “We have a demo kit that allows us to quickly deliver customized solutions to our partners, under a non-disclosure agreement. But until the big companies sort out their highvolume yield issues for flexible displays, we won’t be able to disclose who is working with us or trying out our technology” Papakostas concluded. E-ink a winner in wearables By Julien Happich Slim, flexible and very low power due to their bi-stable property, E-ink displays could be the best match for today’s power-conscious wearable applications. Until full colour flexible OLED screens can be manufactured with acceptable yields, it looks like the only rugged and shatter-proof alternative to power-hungry LCDs. So much so that despite competing in the smart watch arena with “traditional” TFT LCD-based designs such as the Smart- Watch 3 it launched last September, Sony is also developing watch bracelets based on E-ink, albeit without all the bells and whistle that more responsive screens can offer. Last September, the company officially brought to market the SmartBand Talk, designed as a life-logger, bringing call handling and voice control with an always-on curved 1.4” E-ink display. But at the same time, Sony was further exploring that route using a Japanese crowd-funding website to probe the market with a bracelet watch fully cut out of an E-ink display sheet (dial and belt included). Here, the whole display and bracelet can change of style, with 24 design patterns selectable manually using the crown, but also with gestures-enabled on-off dial functions or through time-dependent routines. The whole unit could operate two-months in a row on a single button battery (way better than TFTalternatives, but in my opinion still way too short for a timekeeping piece). The FES watch as seen on crowdfunding For discretion, the new product site Makuake. was crowd-sourced under the spin-off company name Fashion Entertainments (FES), and the FES watch quickly became a success, getting over its initial two million yen bid (approximately 13,000 Euros). After completing successfully its first crowdsourcing campaign, the company initiated another run (dubbed FES watch returns) just to extend the purchase opportunity to new entrants, collecting nearly 64,000 euros at the time of writing and still going. On the crowd-sourcing site, Fashion Entertainments also states that the FES watch is only the first step in the company’s exploration of E-Ink’s potential to develop other fashion products with versatile and configurable skins, such as pattern-changing bow ties, spectacle frames, or shoes. For such accessories, colour E-Ink could be envisaged and configuration could certainly be done through a special app, using a smartphone’s NFC or Bluetooth LE wireless link to program the multi-pattern routines. Multi-pattern configurable accessories using coloure E-Ink. www.electronics-eetimes.com Electronic Engineering Times Europe January 2015 23


EETE JAN 2015
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