The term "printed electronics" is used to describe the use of a method of printing to create electrically functional devices (Blayo and Pineaux, 2005). Since the inception of the printed circuit, printing processes have offered circuit board manufacturers an inexpensive method to mass-produce circuit boards that were accurate, standardized, and functional. Yet printed electronics faces several challenges. One of these is the accurate printing of a thin conductive line. There are numerous critical material characteristics that play a significant role in the capability of the printing processes including conductive inks, dielectric substrates with smooth surfaces, and print resolution.
Typically, print resolutions during optical printing may achieve resolutions as low as 8 mm during the transfer of halftone color images, if one considers the smallest size of a discrete halftone dot. In any printing process there are specific requirements that must be met in order to achieve the best possible print quality. These include the accuracy of the permanent master, ink transfer mechanism pressure, impression pressure, and press speed. When considering printed electronics, achieving a printed line resolution that facilitates electronic capacity and mobility is the foremost challenge.
The human eye is capable of distinguishing objects as small as 25 microns. Thus, both the gravure process and the flexographic process are designed to reproduce at this resolution. For the printing of electrical circuitry, the appropriate electrical functionality can be achieved by a series of 25-mm line widths, separated by 25-mm non-conductive spaces (Hagberg, Pudas, Leppavuori, Elsey, and Logan, 2002).
The objective of this study is to analyze the advantages and limitations of manufacturing electronic components using the printing process, while comparing the fine-line printability between the gravure and flexographic printing processes, while considering the limitations of ink, substrate, and processes.