• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.18-23
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• 2022

Electrohydrodynamic jet (e-jet) printing, a type of direct contactless microfabrication technology, is a versatile fabrication process that enables a wide range of micro/nanopattern arrays by applying a strong electric field between the nozzle and the substrate. In general, the morphology and the thickness of polymers/quantum dot micropatterns show a systematic dependence on the diameter of the nozzle and the ink composition with a fully automated printing machine. The purpose of this report is to provide typical examples of e-jet printed micropatterns of polymers/quantum dots to explain the effect of each process variable on the result of experiments. Here, we demonstrate several operating conditions that allow high-resolution printing of layers of polymers/quantum dots with a precise control over thickness and submicron lateral resolution.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.408-414
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• 2012

Screen printing is a printing method that uses a woven mesh to support an ink-blocking stencil by transferring ink or other printable materials in order to form an image onto a substrate. Recently, the screen printing method has applied to micro-electronic packaging by using solder paste as a printable material. For the screen printing of solder paste, metal masks containing a number of micro-holes are used as a stencil material. The metal mask undergoes deformation when it is installed in the screen printing machine, which results in the deformation of micro-holes. In the present study, finite element (FE) analysis was performed to predict the amount of deformation of a metal mask. For an efficient calculation of the micro-holes of the metal mask, the sub-domain analysis method was applied to perform FE analyses connecting the global domain (the metal mask) and the local domain (micro-holes). The FE analyses were then performed to evaluate the effects of slot designs on the deformation characteristics, from which more uniform and adjustable deformation of the metal mask can be obtained.

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.387-392
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• 2018

Nanopatterning is one of the essential nanotechnologies to fabricate electronic and energy nanodevices. Therefore, many research group members made a lot of efforts to develop simple and useful nanopatterning methods to obtain highly ordered nanostructures with functionality. In this study, in order to achieve pattern formation of three-dimensional (3D) hierarchical nanostructures, we introduce a simple and useful patterning method (nano-transfer printing (n-TP) process) consisting of various linewidths for diverse materials. Pt and $WO_3$ hybrid line structures were successfully stacked on a flexible polyimide substrate as a multi-layered hybrid 3D pattern of Pt/WO3/Pt with line-widths of $1{\mu}m$, $1{\mu}m$ and 250 nm, respectively. This simple approach suggests how to fabricate multiscale hybrid nanostructures composed of multiple materials. In addition, functional hybrid nanostructures can be expected to be applicable to various next-generation electronic devices, such as nonvolatile memories and energy harvesters.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.557-558
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• 2006

In this paper, the hysteresis characteristics by bias stress in organic thin film transistors using inkjet printing were investigated. Electron trapping increased threshold voltage for positive gate bias stress and hole trapping decreased threshold voltage for negative gate bias stress. From these phenomena, highly reproducible measurement method which minimized threshold voltage shift by choosing the proper range of gate voltage was suggested. Using this measurement method, we found that electron trapping as well as hole trapping had important influence on hysteresis characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.1
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• pp.81-87
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• 2023

Heaters using the resistance heating principle are used in various industrial fields that require heat and are also essentially used in bidet among small home appliances. A planar heater and a coil-inserted heater mounted on a conventional commercially used bidet have disadvantages and limitations of complicated manufacturing process and local heating. In this study, silver-palladium (Ag-Pd) powder material was used for a screen-printing process that is more advantageous in achieving simplification than the existing process, and a rod-type heater for bidet was manufactured. The on-off cycle test under actual conditions was conducted to confirm the durability and the capability of the fabricated heater, and the fabricated heater operated more than 2,600 on-off cycles, which means it could be applied for a commercial product. In addition, through the on-off cycles under harsh conditions, the cause of failure was identified after the test that the durability limit temperature of the heater was 850℃. Through Ag-Pd rod heater in this study, it is expected to contribute to the efficient development of electrode materials for heaters and the improvement of the durability of heaters in the future.

• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.187-192
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• 2013

Nozzle printing technology has been usually used for adhesive patterning to encapsulate electronic devices. Film formation of functional materials by nozzle printing is a great challenge. The characteristics of nozzle printing of organic ink were investigated systematically in this paper. TAPC as an organic emitting material was used as an ink for nozzle printing experiment to form the patterns in this study. Printed pattern width was increased as the ink flow rate and the printed substrate temperature were increased. The patterns showed a coffee-ring shape.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.279-285
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• 2022

Recently, 3D printing technology has gained increased attention in the manufacturing industry because it allows the manufacturing of complex but sophisticated structures as well as moderate production speed. Owing to advantages of 3D printers, such as flexible design, customization, rapid prototyping, and ease of access, can also be advantageous to sensor developments, 3D printing demands have increased in various active device fields, including sensor manufacturing. In particular, 3D printing technology is of significant interest in tactile sensor development where piezoelectric materials are typically embedded to acquire voltage signals from external stimuli. In regard with piezoelectricity, researchers have worked with various piezoelectric materials to achieve high piezoelectric response, but the structural approach is limited because ceramics have been regarded as challenging materials for complex design owing to their limited manufacturing methods. If appropriate piezoelectric materials and approaches to design are used, sensors can be fabricated with the improved piezoelectric response and high sensitivity that cannot be found in common bulk materials. In this study, various 3D printing technologies, material combinations, and applications of various piezoelectric sensors using the 3D printing method are reviewed.

• Journal of Information Management
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• v.22 no.1
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• pp.39-55
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• 1991

Electronic publishing, vaguely defined area of activities and vaguely defined scope of products, is consisting of electronic or computerized processing of text, images, graphics for publication in one of electronic forms and also in a traditional printing on paper. As it is vague in scope, topics of this paper are of diverse interests. Technological developments related to electronic publishing are rapid in Japan. Activities and events by various organizations, both in the private sector and the public sector, are not few, and interlaced.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.186-189
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• 2001

The main method in micro-etching process, used in manufacturing semiconductors, electronic components, circuits, is Photo Masking method that exposes and develops on the photo-sensitivity solutions or films. This method enables one to process highly precisely, $\pm$0.03 mm in end line location area. But this has limits in a high speed / wide width process, difficulties in endless masking, and the problem of high price. We have developed the direct masking method to make use of Gravure printing, widely used in grocery packing sheet printing. We made cylinder tools to influence the masking quality by laser stream process. We have confirmed that the end line location accuracy in the line width of the product is improved from 0.12 mm to $\pm$0.07 mm level, after etching process.

• Transactions of the KSME C: Technology and Education
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• v.5 no.1
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• pp.7-21
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• 2017

Printed Electronics is a relatively new subject where electronics and display appliances are mass-produced by employing low-cost printing techniques with electronic materials suspended in a liquid medium, and many efforts to develop materials, process and equipment to commercialize low-cost electronics and display parts have been made since 2007 in the Republic of Korea. In this work, the development status of printing equipment for printed electronics and display components in the size of a few micrometers and tens of micrometers is briefly introduced.