摘要
Organic light-emitting diode (OLED) displays have unique characteristics, namely, wide viewing angles, portability, and touchscreen capability, and are thinner and lighter than traditional displays. Such characteristics make OLED displays one of the preferred features for next-generation flexible electronics. However, to maintain high luminous efficiency and achieve long-term operation, the possible failure modes of OLED devices that are embedded in the packaging structure need to be understood because a high flexural load is applied to the structure. These failure nodes can be understood by predicting the contour and estimating the magnitude of flexible stress in each film of OLED devices. Therefore, this research uses an analytical solution which is based on thin film mechanics for flexible multi-stacked films. Moreover, nonlinear finite element analysis (FEA), which is based on the assumption of large deformation, and related experimental tests are utilized to verify the reliability of the mechanical model. Under different radii of bending curvatures, the accurate position of the neutral plane along the direction of total thickness, stiffness, and related stress distribution of each film is calculated by using the derived formula; the result is better than that predicted by FEA. The Young's modulus and thickness of each film are the major factors that affect the stress magnitude and flexibility of the OLED device packaging structure. To explain the behaviors induced by the material properties of films, a parametric analysis of a cover plate within an OLED packaging structure is conducted. The results can be applied to the development of flexible electronics with a long lifespan and mechanical reliability.