ISORG co-founder Laurent Jamet presented large-area printed organic optical sensors which he said could happily replace ITO-based capacitive technologies in today’s touch screens. Not only the optical sensors are flexible and conformable, but they also support innovative 3D gestures and on-screen interactions.
The printed photodetectors operate in the near infrared, with a spectrum operation fully tuneable. They can be laid either below the LCD or OLED surface, or at the periphery of a display and detect a user’s fingers as they block or reflect infrared illumination from surrounding IR LEDs (integrated in a bezel).
This adds a depth effect that could have promising applications for gaming or for the manipulation of virtual 3D objects.
Such sensor arrays could also turn a whole display into a scanning area, ISORG has proven pixel resolutions down to 80 microns, fine enough to perform fingerprint authentication. Jamet mentioned that Intel was evaluating this technology for a new all-in-one computer concept.
Smart shelves and in-retail interactive advertising are also a very promising market for such optical sensors, according to Jamet. In the future, shelves could be covered with optical sensor films, each cell acting as a light sensor so when a consumer lifts a product from a shelf, the appropriate advertising or product promotion shows up on a nearby display.
These interactive surfaces could not only serve to manage shelf inventory for faster replenishment, but they would also gather data about which products attract the most customers, replacing today’s camera-based analytics. As for large advertising displays, these could be functionalized for 3D interaction, either in full or partially.
On the organic photovoltaic (OPV) front, marketing and development manager François Barreau at Armor looked at the flexible and semi-transparent OPV cells for urban furniture or even consumer solar rechargeable devices. "With printed OPV, we are not selling solar panels", he emphasized, "we enable new use cases for solar energy that cannot be addressed by traditional modules".
"Even with its comparatively low efficiency, according to a study carried out by Europeen project SUNFLOWER, OPV has the potential to be the technology producing the least grams of CO2 per kWh, with a very short energy payback time (within a month), just after hydro-electric energy", Barreau told the assembly.
Feeligreen’s CEO Dr. Christoph Bianchi gave us an update on his company’s roadmap. Having developed a transdermic drug delivery platform in the form of disposable printed patches, Bianchi told us he now wants to have the pharmaceuticals printed together with the electrodes.
"We have just filed all the patents for this", he boasted, so I can mention it to you. The startup will soon be looking at acquiring a pharmaceutical company so it will be able to formulate its own drug patterns, all in one go with the required metal layers for the electrodes. "This will allow us to be much more cost-effective while optimizing the iontophoresis process", Bianchi explained.
In the medical sector, professor Christophe Bernard from INSERM exposed his successful use of ultra-flexible printed electrodes, only 4um thick, to study brain messaging functions at neurone level. Before using such electrodes, neuro-researchers used to rely on fixed metal probes going through the skull and then through the brain, but as the brain moves and scarification tissues form around the electrodes, the signal deteriorates in a matter of days or weeks.
By using PDOT-based flexible electrodes, not only the end-probes can move with the brain (for an unaltered signal), but the bio-compatible organic material means there is no rejection and the neurones being probed can be relied upon for longer.
What’s more, on these electrodes, Bernard’s team implemented a transistor in direct contact with the brain, enabling a signal pre-amplification gain of 20dB. The long term goal of his research would be to be able to record and decode brain information in order to establish a brain-machine interface. This would allow the electrodes’ wearer to send the commands to an intelligent assistant or to an exoskeleton.
According to market research firm IDTechex, the emerging battle grounds for printed electronics will be stretchable electronic textiles and conductive 3D surfaces for large area applications.
And beyond organic-based printed electronic devices, the 5èmes Rencontres de l’électronique imprimée was an opportunity for representatives from the more traditional printing and textile industries to share their ideas for a successful reconversion, adding electronic functionalities to their product portfolio.
President of the ATEP (the French association of publishing and advertising engineers), Hervé Rouher sees the integration of printed electronics into the traditional printing industry as a way to bring more value and create new jobs in a sector that faces an unprecedented crisis.
"Small and medium enterprises in this sector should embrace printed electronics to add sensory functions and turn their paper substrate into large-area active components" he said. Rouher would rather talk about functionalized printing rather than printed electronics, an expression he finds too narrow when you consider how versatile printing technology can be, on paper or other substrates.
The most immediate markets for functionalized prints include luxury labelling and packaging, smart labelling for the food and medical sectors, and packaging in general.
Philippe Guermonprez, Collective R&D manager for the French Institute of Textile and apparel (IFTH) shared a similar view, looking at functionalizing textiles with either through screen printing processes or weaving electronic components as specialized yarns.
Though he mentioned that printing on textiles is a very different story, since the substrate is three-dimensional, porous, deformable and often stretchable. All this makes printing electronic components much more difficult, and as more sensors are being integrated into fitness or health-monitoring garments, connectivity remains a challenge. On several occasions, Guermonprez reminded us that wash cycles at 80ºC were the most dreaded pass or fail test for any fabric integrating electronic components, submitting all the material layers to both mechanical wear and moisture.
The most promising market in this sector include entertainment (with interactive or light-emitting clothes), sports (with fitness monitoring), but also so-called geotextiles to monitor large structure deformations.
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