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We have analyzed a metal direct printing method using roll printing technology for the low cost process in TFT-LCD fabrication. The silver metal electrodes patterned down to 3 μm in space width between lines were directly printed by this method. Very low line resistivity of 4.5 μΩ⋅cm was obtained, which is comparable to that of the AlNd metal alloy for the gate electrode of TFT-LCD. Furthermore, we evaluated the transfer characteristics of an a-Si:H TFT using directly printed silver material as a gate line.

— Recently, potential breakthrough technologies for low-cost processing of TFT-LCDs and new process developments for flexible-display fabrication have been widely studied. A roll-printing process using etch-resist material as a replacement for photolithographic patterning was investigated. The characterization of the properties of patterns formed in roll printing, a method to fabricate cliche plates for fine patterns, and the design of a new formulation for resist printing ink is reported. The pattern position accuracy, which is one of the most important issues for the successful application of printing processes in display manufacturing was studied and how it can be improved by optimizing the blanket roll structure is explained. New design rules for the layout of the thin-film-transistor array was derived to improve the compatibility of roll printing. As a result, a prototype 15-in.-XGA TFT-LCD panel was fabricated by using printing processes to replace all the photolithographic patterning steps conventionally used.

Recently, breakthrough technology for the low cost process in TFT-LCD and new process development for integrating it with flexible display fabrication has been studied importantly. As a way of achieving this goal, we have investigated roll printing process with etch-resist material as non-photolithographic patterning technique. We characterized the properties of patterns formed with roll printing process, derived the design concepts, and found the best way to fabricate the panel by this process. Thus, we were made the prototype of 15″ XGA TFT-LCD panel by using all printing processes.