Potential up-scaling of inkjet-printed devices for logical circuits in flexible electronics

Inkjet Technology is often mis-believed to be a deposition/patterning technology which is not meant for high fabrication throughput in the field of printed and flexible electronics. In this work, we report on the 1) printing, 2) fabrication yield and 3) characterization of exemplary simple devices e.g. capacitors, organic transistors etc. which are the basic building blocks for logical circuits. For this purpose, printing is performed first with a Proof of concept Inkjet printing system Dimatix Material Printer 2831 (DMP 2831) using 10 pL small print-heads and then with Dimatix Material Printer 3000 (DMP 3000) using 35 pL industrial print-heads (from Fujifilm Dimatix). Printing at DMP 3000 using industrial print-heads (in Sheet-to-sheet) paves the path towards industrialization which can be defined by printing in Roll-to-Roll format using industrial print-heads. This pavement can be termed as "Bridging Platform". This transfer to "Bridging Platform" from 10 pL small print-heads to 35 pL industrial print-heads help the inkjet-printed devices to evolve on the basis of functionality and also in form of up-scaled quantities. The high printed quantities and yield of inkjet-printed devices justify the deposition reliability and potential to print circuits. This reliability is very much desired when it comes to printing of circuits e.g. inverters, ring oscillator and any other planned complex logical circuits which require devices e.g. organic transistors which needs to get connected in different staged levels. Also, the up-scaled inkjet-printed devices are characterized and they reflect a domain under which they can work to their optimal status. This status is much wanted for predicting the real device functionality and integration of them into a planned circuit

Flexible and conformable strain gauges for smart pressure sensors systems: Static and dynamic characterization

An innovative segment of the semiconductor and electronics industry in the last years is driven by new sensors embedded in smart devices and systems with thin form factor, connected to existing infrastructures via standard communication interfaces. The increased maturity of industrial sensor technologies and associated readout electronics enabled new products penetrating multiple market sectors. Among the different classes of smart sensing systems that can be realized with thin and truly flexible form factor, thin film strain gauges are ideally suited for the implementation of pressure sensing membranes. In this work we will focus on the development of static and dynamic testing methods of a strain gauge module whose applications are intended as a flexible and conformable strain/pressure sensor, adaptable for wireless communications

Ambient Light Organic Sensor in a Printed Complementary Organic TFT Technology on Flexible Plastic Foil

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Technologies for printing sensors and electronics over large flexible substrates: a review

Printing sensors and electronics over flexible substrates is an area of significant interest due to low-cost fabrication and possibility of obtaining multifunctional electronics over large areas. Over the years, a number of printing technologies have been developed to pattern a wide range of electronic materials on diverse substrates. As further expansion of printed technologies is expected in future for sensors and electronics, it is opportune to review the common features, complementarities and the challenges associated with various printing technologies. This paper presents a comprehensive review of various printing technologies, commonly used substrates and electronic materials. Various solution/dry printing and contact/non-contact printing technologies have been assessed on the basis of technological, materials and process related developments in the field. Critical challenges in various printing techniques and potential research directions have been highlighted. Possibilities of merging various printing methodologies have been explored to extend the lab developed standalone systems to high-speed roll-to-roll (R2R) production lines for system level integration

The rise of flexible electronics in neuroscience, from materials selection to in vitro and in vivo applications

Neuroscience deals with one of the most complicate system we can study: the brain. The huge amount of connections among the cells and the different phenomena occurring at different scale give rise to a continuous flow of data that have to be collected, analyzed and interpreted. Neuroscientists try to interrogate this complexity to find basic principles underlying brain electrochemical signalling and human/animal behaviour to disclose the mechanisms that trigger neurodegenerative diseases and to understand how restoring damaged brain circuits. The main tool to perform these tasks is a neural interface, a system able to interact with brain tissue at different levels to provide a uni/bidirectional communication path. Recently, breakthroughs coming from various disciplines have been combined to enforce features and potentialities of neural interfaces. Among the different findings, flexible electronics is playing a pivotal role in revolutionizing neural interfaces. In this work, we review the most recent advances in the fabrication of neural interfaces based on flexible electronics. We define challenges and issues to be solved for the application of such platforms and we discuss the different parts of the system regarding improvements in materials selection and breakthrough in applications both for in vitro and in vivo tests

Magnetosensitive e-skins for interactive electronics

The rapid progress of electronics and computer science in the last years has brought humans and machines closer than ever before. Current trends like the Internet of Things and artificial intelligence are closing the gap even further, by providing ubiquitous data processing and sensing. As this ongoing revolution advances, novel forms of human-machine interactions are required in an ever more connected world. A crucial component to enable these interactions is the field of flexible electronics, which aims to establish a seamless link between living and artificial entities using electronic skins (e-skins). E-skins combine the functionality of commercial electronics with the soft, stretchable and biocompatible characteristics of human skin or tissue. Until lately, the focus had been to replicate the standard functions associated with human skin, such as, temperature, pressure and chemical detection. Yet, recent developments have also introduced non-standard sensing capabilities like magnetic field detection to create the field of magnetosensitive e-skins. The addition of a supplementary information channel—an electronic sixth sense—has sparked a wide range of applications in the fields of cognitive psychology and human-machine interactions. In this thesis, we expand the concept of magnetosensitive e-skins to include the notion of directionality, which utilizes the full interaction potential of the magnetic field vector. Also, we introduce the use of flexible magnetoelectronics in virtual/augmented reality and human-computer interfaces. Three main results are attained in the course of this work: (i) we first demonstrate how magnetosensitive e-skins can be used as humanmachine interfaces driven by permanent magnet sources in the range of 5 mT. (ii) Building upon this milestone, we realize the first magnetosensitive e-skins which are driven by the earth’s magnetic field of 50 μT. (iii) We fabricate magnetosensitive e-skins which push the detection limit below 1 μT. The magnetosensitive e-skins in this work open exciting possibilities for sensory substitution experiments and sensory processing disorder therapies. Futhermore, for human-machine interactions, they provide a new interactive platform for touchless and gestural control in virtual and augmented reality scenarios beyond the limitations of optics-based systems.Der rasante Fortschritt der Elektronik und der Informatik in den letzten Jahren hat Mensch und Maschine nähergebracht als je zuvor. Aktuelle Trends wie das Internet der Dinge und künstliche Intelligenz schließen die Lücke noch weiter, indem sie eine allgegenwärtige Datenverarbeitung und -erfassung ermöglichen. Mit fortschreitender Revolution sind neue Formen der Mensch-Maschine-Interaktion in einer immer vernetzter werdenden Welt erforderlich. Eine entscheidende Komponente, um diese Interaktionen zu ermöglichen, ist das Gebiet der flexiblen Elektronik, das darauf abzielt, mithilfe elektronischer Häute (e-skins) eine nahtlose Verbindung zwischen lebenden und künstlichen Entitäten herzustellen. E-skins verbinden die Funktionalität kommerzieller Elektronik mit den weichen, dehnbaren und biokompatiblen Eigenschaften menschlicher Haut oder menschlichen Gewebes. Bis vor kurzem lag der Schwerpunkt auf der Nachbildung der mit der menschlichen Haut verbundenen Standardfunktionen wie Temperatur-, Druck- und Chemikalienerkennung. Jüngste Entwicklungen haben jedoch auch nicht standardmäßige Erfassungsfähigkeiten wie die Magnetfelderkennung eingeführt, um das Feld magnetoempfindlicher e-skins zu erzeugen. Die Hinzufügung eines zusätzlichen Informationskanals - eines elektronischen sechsten Sinns - hat eine breite Palette von Anwendungen auf den Gebieten der kognitiven Psychologie und der Mensch-Maschine-Interaktionen ausgelöst. In dieser Arbeit erweitern wir das Konzept der magnetoempfindlichen e-skins um den Begriff der Richtwirkung, bei dem das volle Wechselwirkungspotential des Magnetfeldvektors genutzt wird. Außerdem führen wir die Verwendung flexibler Magnetoelektronik in der virtuellen Realität / erweiterten Realität und in Mensch-Computer-Schnittstellen ein. Im Verlauf dieser Arbeit werden drei Hauptergebnisse erzielt: (i) Wir demonstrieren erstmals, wie magnetoempfindliche e-skins als Mensch-Maschine-Schnittstellen verwendet werden können, die von Permanentmagnetquellen im Bereich von 5 mT angetrieben werden. (ii) Aufbauend auf diesem Meilenstein realisieren wir die ersten magnetoempfindlichen e-skins, die vom Erdmagnetfeld von 50 μT angetrieben werden. (iii) Wir fertigen magnetoempfindliche e-skins, bei denen die Nachweisgrenze unter 1 μT liegt. Die magnetoempfindlichen e-skins in dieser Arbeit eröffnen aufregende Möglichkeiten für sensorische Substitutionsexperimente und Therapien bei sensorischen Verarbeitungsstörungen. Darüber hinaus bieten sie für die Mensch-Maschine-Interaktion eine neue interaktive Plattform für die berührungslose und gestische Steuerung in virtuellen und Augmented Reality-Szenarien, die über die Grenzen optikbasierter Systeme hinausgehen

Floor sensor development using signal scavenging for personnel detection system

"July 2010.""A Thesis Presented to The Faculty of the Graduate School At the University of Missouri--Columbia In Partial Fulfillment Of the Requirements for the Degree Master of Science."Thesis supervisor: Dr. Harry Tyrer.Falls have been a major cause of injuries likes fractures, head trauma in elder people. In many cases, these injuries have been fatal. This being a major concern of the Alzheimer's Association, a 'Smart Carpet' to detect a person's fall and accordingly generate an alarm was important. We developed faux floors and an actual floor for testing and demonstration to detect motion. We used a novel technique of signal scavenging to detect presence of the person. Aluminum foils were used as sensors as they were conducive to the applied pressure on them. Rigorous tests and experiments were performed on the faux floor sized 1m x 1m (3feet x 3feet) and 2.1m x 1m (7feet x 3feet) using these aluminum sensors. The noisy output pattern of the aluminum sensor was signal conditioned and converted into digital format using Op-Amps. The digital signal was later interfaced with a micro-controller unit and displayed onto a PC. Graphical analysis with ROC space and personal experience with utilization of the faux floor system gave us confidence to develop a real floor of the size 3.6m x 3.6m (12feet x 12feet). The results obtained on the full floor were beyond the expectations. Previously observed problems like cross-talk, noise interference and abrupt output behavior of the sensor system were avoided with careful manufacturing of carpet and earthing. With the development of the full floor, we have created a prototype which has high reliability and accuracy to detect motion and can be extensively used for further research.Includes bibliographical references (pages 57-59)