Mechanical reliability enhancement of flexible packaging with OLED display under bending loading conditions

Mechanical model of multi-layer under bending loadings and related stress simulations, based on finite element method (FEM), are proposed. The models are used to analyze the stress/strain characteristic of flexible packaging with organic light-emitting diode (OLED) devices. Under various geometrical combinations of stacked thin films and plastic substrate, the position of neural axis (N.A.) which is regarded as a key design parameter to minimize stress impact for the concerned OLED devices, is acquired by the present methodology. Through the performance of sensitivity analysis, both the thickness and mechanical properties of cover plate are shown to have an obvious effect in the determination of N.A. location. Movement of N.A to the region of indium tin oxide (ITO) film is achievable because the corresponding scale smaller than 5 μm in thickness or 40 GPa in Young´s modulus for a cover plate is derived. In addition, several radii of curvature are selected to examine the reliable mechanical tolerance and to provide insight into the estimated reliability of foldable displays.