Packaging designs and flexural stress estimation for thin-film types of OLED devices

Fatigue behavior with an extreme flexural stress loaded on OLED devices has been greatly paid attention while the packaging structure having multi-stacked films becomes thinner and more flexible. To reduce mechanical impact and enhance reliability for OLED and related critical film materials, a derived mechanical model of plural layers is presented. Moreover, a nonlinear finite element analysis combined with the approach of full factorial design is performed to explore several concerned mechanical parameters within a whole structure. The results reveal that the thickness of PI_substrate is the most dominant to determine the position of neutral axis and the bending stress of indium tin oxide film, separately. It is also found that all the significances of main effects for each factor are obviously larger than the interaction effect among them. Consequently, the use of either thinner film or softer constitute for each layer could be able to reduce ITO stress effectively.