Reliability of transparent conducting substrates for rollable displays: A cyclic loading investigation

Abstract

Abstract— Failure mechanisms for flexible conducting substrates are investigated herein in the context of rollable/flexible display applications. Cyclic loading experiments (substrates subjected to multiple cycles of tensile strain) were carried out on both ITO‐coated PET and PEDOT:PSS‐coated PET substrates. The resistance was measured after each bending cycle. The resistance increased with the number of cycles and was not reversible. Even when the tensile strain on the ITO/PET was below the virgin cracking threshold (∼2%) previously reported [Appl Phys Lett 76, 1425 (2000)], slight increases in resistance were measurable after just a few cycles.

A physics of failure based qualification process for flexible display interconnect materials

“…This computer also controls the rotation of a stepper motor which in turn controls the smooth rotation of the mandrel via a timing belt [Gorkhali 2004]. …”

P‐159L: Late‐News Poster: A Liquid Crystal Based Contact Lens Display Using PEDOT: PSS and Obliquely Evaporated SiO2

“…Notwithstanding the LC cell could still be switched, the long term reliability can be assumed to be small in such a configuration, especially since additional stresses introduced during handling of the cell could further crack the ITO layer and permanently destroy conductive paths. We therefore chose poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as an alternative, being a conductive polymer with a proven flexibility [6]. For the alignment of the LC molecules, we selected obliquely evaporated SiO 2 , providing a robust alignment layer which requires only a low temperature deposition step, thereby reducing the risk of introducing undesired thermal stresses in the underlying PET film.…”

OLED Displays on Plastic

“…The critical strain -the strain above which a film will form a crack -of individual layers is another factor that will determine the mechanical reliability of the composite substrate and the extent to which it can bend. A considerable amount of study is being directed at developing testing methods for understanding these issues (Nisato 2004;Bouten 2002;Gorkhali et al 2003).…”