An inkjet printed stripe-type color filter of liquid crystal display

In this paper, we propose a comprehensive concept and new design of a drop-on-demand (DOD) inkjet printing process for fabricating color filter (CF) layers of liquid crystal displays (LCDs) onto the structured surfaces of flat substrates, composed of 'physical sidewalls' for aligning and controlling the liquid morphology. Several fundamental guidelines of the design have been addressed in current inkjet-printing techniques. Using a droplet generator (printhead) of the deposition system, the color-ink drops can be jetted and placed over the specific domains, where the sidewalls align the flow merged from a stream of droplets and fulfill the coverage of the defined areas, in which the geometrical relations correlating the droplets and sidewalls are explicitly expressed in the study. According to the results of the simulation and analysis, the proposed sidewalls, acting as the physical barriers, can control the liquid morphology through the simple geometric factors such as sidewall widths, heights and contact angles. The experimental results showed that the solid RGB color layers were self-assembled from the liquid droplets and formed with the uniform thickness, except for the neighborhood of the sidewalls. It indicated that the sidewalls serving as 'physical barriers' had a remarkable effect in confining and self-aligning the droplet flow within the desirable regions. This inkjet-printing method would alternatively offer one cost-effective and high-flexibility method for the production of the versatile LCD CF, thus being particularly beneficial for large-area printing and flexible substrates.