Abstract
Several printing techniques for fabricating organic thin film transistor arrays have been studied. However, conventional printing techniques such as flexo, screen, and ink jet printing show poor printing resolutions of only 20 μm or higher, which is not sufficient for high-resolution thin film transistors (TFTs).Reverse offset printing has attracted much attention recently because of its ability to make fine patterns of less than 5 μm with smooth surfaces. The key point of such printing is introduced here, along with several functional inks developed for printed TFTs. From the perspective of enabling the industrialized production of printed flexible TFTs, the key points for printing technology include a technique for fabricating fine patterns, a method for realizing precise overlays, and the construction of simple and low-cost production processes. This paper introduces a promising printing process for achieving precise pattern overlays on a flexible plastic substrate, which will significantly simplify the printing process. This is a wet-on-wet process for reverse offset printing, in which subsequent layers can be printed on previous semi-dried layers, after which all the layers are sintered simultaneously.
