Dependent Analyses of Multilayered Material/Geometrical Characteristics on the Mechanical Reliability of Flexible Display Devices

A generalized solution for the bending stress/strain expression of flexible display composed of multi-stacked thin films is presented in this letter. Flexible display comprises an arbitrary number of films combined with dissimilar thicknesses and linear-elastic mechanical characteristics. Specific consequences for alternate layered systems are estimated to reveal the elementary trends of the dependencies of normalized bending strain and neutral axis (N.A.) position on the modulus and thickness ratios of the concerned layers. An actual architecture of flexible display is also provided as an example to calculate the results and is compared with the simulated predictions of finite element analysis. With various material selections of cover plate, the induced stresses on transparent conducting film and the position of the N.A. plate are separately investigated. Moreover, the impact of bending radius on the mechanical reliability of flexible encapsulation is also found. The presented results serve as a design guideline for the infrastructure optimization of flexible display devices without electrical failures.