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Roll-to-roll gravure (R2Rg) has become highly affiliated with printed electronics in the past few years due to its high yield of printed thin-film transistor (TFT) in active matrix devices, and to its low cost. For printing TFTs with multilayer structures, achieving a high-precision in overlay printing registration accuracy (OPRA) is a key challenge to attain the high degree of TFT integration through R2Rg. To address this challenge efficiently, a digital twin paradigm was first introduced in the R2Rg system with an aim to optimize the OPRA by developing a predictive model based on typical input variables such as web tension, nip force, and printing speed in the R2Rg system. In our introductory-level digital twin, errors in the OPRA were collected with the variable parameters of web tensions, nip forces, and printing speeds from several R2Rg printing processes. Subsequently, statistical features were extracted from the input data followed by the training of a deep learning long-short term memory (LSTM) model for predicting machine directional error (MD) in the OPRA. As a result of training the LSTM model in our digital twin, its attained accuracy of prediction was 77%. Based on this result, we studied the relationship between the nip forces and printing speeds to predict the MD error in the OPRA. The results indicated a correlation between the MD error in the OPRA and the printing speed, as the MD error amplitude in the OPRA tended to decline at the higher printing speed. [ABSTRACT FROM AUTHOR]

Roll‐to‐roll (R2R) printed electronics have been considered as the holy grail for the low‐cost manufacturing of expendable and compliant electronic devices. However, a lapse exists in unlocking the full potential of R2R printed electronics in that there has yet to be a R2R foundry able to integrate complementary metal‐oxide‐semiconductor (CMOS) logic gates into such devices. Herein, a R2R printing foundry based on a complementary design rule of physical dimension in which the rheology of electronic inks, R2R printing speed, overlay printing registration accuracy and device design are complementary to one another is proposed. As a proof of concept of the complementary design rule, 44 single walled carbon nanotube‐based p‐type and n‐type thin film transistors are printed to integrate a CMOS ring oscillator, six CMOS NAND gates, and a CMOS OR gate for 4‐bit code generation through a R2R gravure printer. This low‐bit code generator fabricated via R2R printing illustrates is the first step in establishing R2R printing foundry for manufacturing logic gate‐based flexible devices. [ABSTRACT FROM AUTHOR]

Printed Electronics: The First Step towards a R2R Printing Foundry via a Complementary Design Rule in Physical Dimension for Fabricating Flexible 4-Bit Code Generator (Adv. A basic R2R electronics printing foundry concept comprising nanomaterial based electronic inks, R2R printing speed, overlay printing registration accuracy, and device design is described by Gyoujin Cho and co-workers in article number 2000770. They demonstrate their system by printing 44 single walled carbon nanotube (SWCNT)-based p-type and n-type TFTs to integrate a ring oscillator, six NAND gates, and a OR gate for 4-bit code generation through a R2R gravure printer. [Extracted from the article]

Printed electronics are challenged for showing the working concept of the roll‐to‐roll (R2R) printed 13.56 MHz passive radio frequency identification (RFID) tag for the application in wireless identification (ID) and authentication to prevent counterfeits with the cost of a penny. However, the concept of the penny RFID tag is not successful yet because of the major limit in integrating a number logic gates by a high throughput R2R printing method. Herein, a new way of printed electronics is developed by integrating an electrophoretic quick response (QR) code as write once read many type of memory circuitry to integrate with a R2R printed wireless 1‐bit code generator. Through the electrophoretic QR code integration with the wireless 1‐bit code generator, only six logic gates (12 thin film transistors) are enough to wirelessly provide 2953 bytes of authentic information by utilizing two functions of smartphone, near field communication, and camera. [ABSTRACT FROM AUTHOR]