Flexible and Conformal Environmental Barrier Technology for Displays

A low-cost, high performance thin-film oxygen and moisture permeation barrier remains a critical issue to be solved for the successful development and commercialization of flexible OLED displays. In this proposal our project team at Universal Display Corporation (UDC) and Princeton University plan to develop a novel technology by which alternating layers of polymerized hexamethyl disiloxane (PHMDSO) and silicon oxide SiOx or silicon oxycarbide (SiO¬xCy) films are deposited in a single chamber plasma-enhanced chemical vapor deposition (PECVD) system. This multilayer barrier film will demonstrate excellent optical transmission and barrier performance comparable to the state-of-the-art conventional OLED encapsulation technology such as desiccant loaded glass/metal epoxy seal. Our goal is to apply this multilayer encapsulation technology to our low power consumption phosphorescent OLED (PHOLED) technology to enable the low cost manufacture of flexible AMOLED displays on either plastic or metal foil substrates. Improved flexibility will be achieved by minimizing the overall built-in stress by controlling the growth conditions for the alternating polymer and inorganic layers such that the compressive and tensile stress in the adjacent layers can be compensated. The compatibility of the barrier film with thin-film transistor (TFT) back plane processes will also be investigated.