Extremely Robust Rollable AMOLED Display With Very Small Waviness of Surface Using Smart Module and Panel Structure

ABSTRACT An extremely robust rollable AMOLED display with excellent surface quality (very low waviness) using smart module and panel structure was proposed. Using high‐energy damping OCA (Optical Clear Adhesive) of PUA (polyurethane acrylate) elastomer with high loss tangent instead of conventional PSA of silicone significantly increased pen drop height from 4 to 7 cm and angle of pendulum in Charpy test from 68° to 120° (maximum angle of Charpy test equipment used in this study) when estimating side‐impact property of OCA of PUA elastomer with high loss tangent. Applying hybrid‐polymer OC (overcoating) material directly on and under panel remarkably improved ball drop height from 5 to 21 cm. Replacement of symmetric multi‐joint bar of stainless steel with asymmetric multijoint bar of CFRP (carbon fiber reinforced plastics) greatly enhanced surface quality of rollable display module and lessened Kc (one of evaluation standard for waviness) from 0.80 to 0.44 after 240 h at the condition of 60°C/93% RH, where smaller K c means smaller waviness of rollable display module. We also demonstrated IT and automotive rollable AMOLED rollable display with rolling radius of 7 and 50 mm, respectively. Touch integrated panel was also applied for the rollable display.