Effect of Interlayer Stress on U Bends and Water Droplet Bends

Abstract

The interlayer stress (IS) analysis of the flexible active-matrix organic light-emitting diode (AMOLED) panel is critical for decreasing the stress concentration and reducing the risk of overall screen failure. This article relies on the linear elastic models of ABAQUS to simulate finite element analysis of foldable panels. This article discussed three sensitive locations of the flexible AMOLED panel caused by two different bending methods including U bends and water droplet bends. The finite element method for simulating the layer analysis was constructed to analyze the effect of optically clear adhesive (OCA) film thickness on the distribution of stress and strain. The module can be optimized by changing the thickness and shear modulus of OCA. With the decrease of OCA thickness and the increase of stiffness, the maximum stress of the organic light-emitting diode (OLED) layer is decreased by 20% which is 55 Mpa; meanwhile, the IS of the entire module is reduced by about 30%.

Large strain mechanical behaviors of optically clear adhesives for flexible electronic devices under different temperature, humidity, and strain rates

“…Moreover, the method employing the WLF equation allows for the determination solely of the storage modulus at specific temperatures, precluding the derivation of the stress–strain curve under conditions of large strain loading. Considering that OCA will withstand over 500% strain in finite element simulation, 16,17 the aforementioned testing approach is not directly suitable. Hence, it is imperative to conduct large strain loading at various temperatures and subsequently fit the constitutive parameters under large strain, examining the temperature‐induced variations in material modulus.…”