Individual drive cross-coupled control system to compensate for measurement time-delay for roll-to-roll contact pressure uniformization

As the market demand for products such as flexible displays, IoT devices, and healthcare devices increases, attention has been drawn to printed electronics by a roll-to-roll process that can continuously produce electronic products on flexible substrates using functional inks. In particular, printed patterns need to be uniform in terms of the line width and thickness, which requires uniform control of the contact pressure during the roll-to-roll process, in processes that require ultra-fine pattern printing such as thin-film transistors for flexible displays. Because the contact pressure is indirectly measured using load cells, the performance of the conventional contact pressure control method tends to deteriorate due to the occurrence of time-delay and magnitude errors. Using the transfer function between the actual contact pressure and load cell, the time-delay is measured and compensated. To achieve contact pressure uniformization, the individual drive cross-coupled control system with the time-delay compensation is proposed.