Winding of interleaved materials

Abstract

The manufacturing of flexible display products has very tight specifications on the dimensional changes between the coating stations or between different passes of a multi-pass coating process. Web stretching and stress relaxation during conveyance and roll storage all contribute to the dimension stability of this product, and therefore are potential concerns. The quality of a flexible display is very sensitive to defects in the films that are used as part of the assembly. Many film components used in the display are very delicate and can be damaged during web handling. To protect the film from damage during the winding process, it can be interleaved with another film, typically one that is softer and significantly cheaper. This paper reports data from a stress relaxation test on a specific polyethylene terephthalate (PET) web, and on the modeling of the stress development, stress relaxation, and dimensional changes of the PET from roll winding and wound roll storage. We also present modeling results and empirical data on the winding of interleaved films.