Interfacial fracture investigation of patterned active matrix OLED driven by amorphous-Si TFTs under film-type packaging technology

Considering the structural stability for active-matrix organic light-emitting diode (AMOLED) application, the reliability of lamination interfaces has become a major concern. The comprehensive influence of structural design integrated with material selections should be carefully examined and estimated. The layout effect of embedded pattern defined layer (PDL) plays an important role in the actual AMOLED architecture. To address the issue of stress-induced failure mechanism of PDL under external loads due to external bending, fracture mechanics-based finite element analysis integrated with Tsai–Hill criterion is utilized in this research. Simulated results indicate that the declined thickness and 45° oblique angle design for PDL prevents the failure occurrence of concerned interfaces. Notably, multiple neutral axis (NA) occurs when an extra-low Young’s modulus of pressure-sensitive adhesive (PSA) is considered. Multiple NA design prevents brittle fracture failure occurrence in gas barrier architecture, while these multiple NAs shift to adjust to the foregoing location. Accordingly, a proper arrangement of these multiple NAs in AMOLED packaging encapsulation through the selection of material characteristics and stacked thickness of PSA thin film has the advantage to enhance structural reliability.