Other affiliations: Jeju National University
Bio: Ganeshthangaraj Ponniah is an academic researcher from Shiv Nadar University. The author has contributed to research in topics: Roll-to-roll processing & Fuzzy logic. The author has an hindex of 4, co-authored 9 publications receiving 43 citations. Previous affiliations of Ganeshthangaraj Ponniah include Jeju National University.
TL;DR: In this paper, a fuzzy logic-based hybrid approach has been followed that specifically targets the printed electronics industry and this method considerably reduces the interactions between the various tension spans in a R2R system.
Abstract: Control of web tension is crucial for maintaining quality of products processed on roll-to-roll (R2R) system. An R2R system can be divided into different tension spans which interact with each other. But converting industries tend to neglect these interactions and use decentralized single-input–single-output (SISO) control approaches to deal with tension control. Multi-input–multi-output approaches have been reported in literatures but are practically not in use. Interaction between the various tension spans is unavoidable as they are all connected by a single web. Disturbances produced in a span tend to travel further downstream along the direction of web travel. When the number of spans is less or the disturbance amplitudes are small, this does not present a big challenge and simple SISO control is sufficient. But when the amplitudes of disturbances produced in processing is large—as is the case with printed electronics—or the number of spans is large or both, then the interactions cannot be neglected. R2R-based offset printers have the potential for mass production of precision-printed electronics. In this paper, a fuzzy logic-based hybrid approach has been followed that specifically targets the printed electronics industry and this method considerably reduces the interactions. The algorithm has been designed such that it takes information from previous span to reduce the propagation of tension disturbances to the given span. This has been achieved through online computation of correlation coefficient and reducing the interaction through fuzzy feedback control.
09 Jan 2013
TL;DR: Experimental results show that the self-learning algorithm offers a solution to decouple speed and tension in a multispan roll-to-roll system by applying regularized variable learning rate backpropagating artificial neural networks.
Abstract: The mass production of printed electronic devices can be achieved by roll-to-roll system that requires highly regulated web tension. This highly regulated tension is required to minimize printing register error and maintain proper roughness and thickness of the printed patterns. The roll-to-roll system has a continuous changing roll diameter and a strong coupling exists between the spans. The roll-to-roll system is a multi-input-multi-output, time variant, and nonlinear system. The conventional proportional–integral–derivative control, used in industry, is not able to cope with roll-to-roll system for printed electronics. In this study, multi-input-single-output decentralized control scheme is used for control of a multispan roll-to-roll system by applying regularized variable learning rate backpropagating artificial neural networks. Additional inputs from coupled spans are given to regularized variable learning rate backpropagating artificial neural network control to decouple the two spans. Experimental...
TL;DR: The results suggest that fabrication of hybrid structure through printed techniques will play a significant role in mass production of printed electronic devices for commercial application by using flexible substrate.
Abstract: This paper is focused on printed techniques for the fabrication of hybrid structure of silver (Ag) grid/poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) (PEDOT:PSS) on polyethylene terepthalate (PET) as a flexible substrate. Ag grid has been printed on PET substrate by using gravure offset printing process, followed by PEDOT:PSS thin film deposition on Ag grid through electrohydrodynamic atomization (EHDA) technique. The important parameters for achieving uniform hybrid structure of Ag grid/PEDOT:PSS through printed techniques have been clearly discussed. Field emission scanning electron microscope studies revealed the uniformity of printed Ag grid with homogeneous deposition of PEDOT:PSS on Ag grid. The optical properties of Ag grid/PEDOT:PSS were measured by UV-visible spectroscopy, which showed nearly 80-82% of transparency in the visible region and it was nearly same as PEDOT:PSS thin film on PET substrate. Current-voltage (I-V) analysis of fabricated hybrid device by using printed Ag grid/PEDOT:PSS as a bottom electrode showed good rectifying behavior with possible interfacial mechanisms. Capacitance-voltage (C-V) analysis was carried over different frequencies. These results suggest that fabrication of hybrid structure through printed techniques will play a significant role in mass production of printed electronic devices for commercial application by using flexible substrate.
TL;DR: The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.
Abstract: The mass production of printed electronics can be achieved by roll-to-roll(R2R) printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output(MISO) regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ±1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.
••07 Jun 2021
TL;DR: In this article, the conveying surface or track is modelled by a bilinear model and the motion of a part on a curved surface mounted upon a linear vibratory feeder is analyzed.
Abstract: The motion of a part on a curved surface mounted upon a linear vibratory feeder is of great importance in mass production. In this article, the conveying surface or track is modelled by a bilinear ...
TL;DR: In this paper, a review of metal mesh-based transparent conductors and their applications in organic optoelectronic devices, including organic and perovskite solar cells, organic light emitting diodes, supercapacitors, electrochromic devices etc.
Abstract: Transparent conducting electrodes (TCEs) have played a pivotal role in driving the continuous development of optoelectronics technologies, which include organic optoelectronic applications. In recent years, there has been huge interest in designing innovative TCEs to replace the conventional indium tin oxide (ITO) electrodes, which suffer from complex fabrication issues and are incompatible with flexible, wearable electronic devices. In this regard, TCEs based on metal meshes are considered to be the best candidates because of their inherently high electrical conductivity, optical transparency, mechanical robustness and, more importantly, cost-competitiveness. In this review, we describe the technology developments of metal mesh-based transparent conductors and their applications in organic optoelectronic devices, including organic and perovskite solar cells, organic light emitting diodes, supercapacitors, electrochromic devices etc. Specifically, we discuss the fundamental features, optoelectronic properties, fabrication techniques and device applications of metal mesh TCEs. We also highlight the important criteria for evaluating the performance of metal mesh electrodes and propose some new research directions in this emerging field.
TL;DR: Two types of water/alcohol-soluble aliphatic amines, polyethylenimine (PEI and PEIE), are studied for their suitability as electron injection layers in solution-processed blue fluorescent organic light-emitting diodes (OLEDs).
Abstract: We study two types of water/alcohol-soluble aliphatic amines, polyethylenimine (PEI) and polyethylenimine-ethoxylated (PEIE), for their suitability as electron injection layers in solution-processed blue fluorescent organic light-emitting diodes (OLEDs). X-ray photoelectron spectroscopy is used to determine the nominal thickness of the polymer layers while ultraviolet photoelectron spectroscopy is carried out to determine the induced work-function change of the silver cathode. The determined work-function shifts are as high as 1.5 eV for PEI and 1.3 eV for PEIE. Furthermore, atomic force microscopy images reveal that homogeneous PEI and PEIE layers are present at nominal thicknesses of about 11 nm. Finally, we solution prepare blue emitting polymer-based OLEDs using PEI/PEIE in combination with Ag as cathode layers. Luminous efficiency reaches 3 and 2.2 cd A–1, whereas maximum luminance values are as high as 8000 and 3000 cd m–2 for PEI and PEIE injection layers, respectively. The prepared devices show a ...
TL;DR: An active control scheme for the rewinding process of a roll-to-roll (R2R) system is investigated and the Lyapunov method is employed to prove the robust stability of the rewind section.
Abstract: In this paper, an active control scheme for the rewinding process of a roll-to-roll (R2R) system is investigated. The control objectives are to suppress the transverse vibration of the moving web, to track the desired velocity profile, and to keep the desired radius value of a rewind roller. The bearing coefficient in the rewind shaft is unknown and the rotating elements in the drive motor are various. The moving web is modeled as an axially moving beam system governed by hyperbolic partial differential equations (PDEs). The control scheme utilizes two control inputs: a control force exerted from a hydraulic actuator equipped with a damper, and a control torque applied to the rewind roller. Two adaptation laws are derived to estimate the unknown bearing coefficient and the bound of variations of the rotating elements. The Lyapunov method is employed to prove the robust stability of the rewind section, specifically the uniform and ultimate boundedness of all of the signals. The effectiveness of the proposed control schemes was verified by numerical simulations.
••19 May 2015
TL;DR: The purpose of this paper is to review the major patterning techniques that have been used for flexible electronics, and to discuss the unique features, advantages, and disadvantages of each.
Abstract: Patterning functional materials is one of the key technologies to enable flexible electronics. In almost every flexible electronic device, individual materials and layers need to be patterned. Moreover, the importance of patterning is probably second only to materials properties in fabricated flexible functional devices. Frequently, patterning is one of the limiting factors in device performance. Flexible electronics depends upon the ability to construct layers of materials having precisely defined architectures and relationships on flexible supports. These structures require the ability to either deposit (additive) or remove (subtractive) materials in a locally controlled fashion (patterning). There are many techniques that have been used to accomplish the patterning of materials on flexible supports. In general, these patterning techniques have either been derived or adapted from conventional electronics processing, from printing processes, or from a hybrid of both. The appropriate choice of patterning technique will depend upon many considerations, including feature size, area of coverage, throughput, registration, environment, position in the overall device structure, and material considerations. Many, if not most device structures will require the use of multiple different patterning techniques. The purpose of this paper is to review the major patterning techniques that have been used for flexible electronics, and to discuss the unique features, advantages, and disadvantages of each. The focus will be on large area, high throughput, additive deposition techniques that can be performed in ambient conditions.
TL;DR: The mathematical model applied to the internal stress in wound roll and winding tension control techniques is summarized, highlighting the idea that defects in the wound roll can be decreased by controlling the winding tension.
Abstract: A continuous roll-to-roll manufacturing process is a next-generation process for the environmentally friendly and low-cost mass production of functional printed devices. Unlike paper product printing, a thin plastic web used as a base film in printed electronic devices is exceptionally vulnerable to elastic and thermal deformations owing to its viscoelastic characteristic, which makes the fabrication of highly integrated printed functional devices very challenging. Herein, we review the representative studies regarding the tension applied to the web during the roll-to-roll process and alternatives for compensating web deformation errors. Also, we introduce the development of the theoretical models expressing the dynamics of tension and lateral motion during the web transporting process. We also discuss applicable controllers for compensating the tension and lateral errors and discuss register errors and associated control techniques. Finally, we summarize the mathematical model applied to the internal stress in wound roll and winding tension control techniques, highlighting the idea that defects in the wound roll can be decreased by controlling the winding tension. The review can be helpful in the design of web dynamic control systems in the multi-layer roll-to-roll manufacturing process.