A high-flexible multi-objective stochastic planning system based on nozzle-combined printing in display manufacturing

Inkjet printing is a new display manufacturing technology with high efficiency and low cost. Accurate control of the pixel ink volume uniformity is key to realizing large-scale printing display manufacturing. In the continuous printing process on multiple substrates, a major challenge in volume uniformity control is solving the problem of overall droplet volume variation of the printhead caused by uncertain factors such as the changes in printhead temperature, ink pressure and nozzle plate wettability. In this paper, a multi-objective stochastic planning system based on nozzle-combined printing for accurate control of the pixel ink volume uniformity under overall droplet volume variation is proposed, which can improve the flexibility and adaptability of the display printing system. Firstly, a nozzle-combined printing planning system based on a droplet volume uncertainty set and a rolling update strategy is proposed. The overall droplet volume variation is added to the printing planning system as an uncertainty set, and the set parameters are iteratively updated through multilayer closed-loop feedback during the printing process. Secondly, a new multi-objective printing stochastic planning model is established to realize comprehensive optimization of the pixel ink volume uniformity and printing efficiency. Finally, the proposed system was verified by pixel printing experiments on self-developed display printing equipment. The experimental results showed that the system could achieve a pixel film thickness uniformity of 1.54 % under droplet volume variation, which was 80 % lower than that obtained with the traditional method. • Overall droplet volume variation can lead to pixel film thickness nonuniformity and produce Mura. • The printing planning system improves flexibility by adding droplet volume uncertainty set. • The model comprehensively optimizes the pixel ink volume uniformity and printing efficiency. • The achieved film thickness uniformity is 80 % lower than that obtained by the traditional method.