P‐88: Thin Film Encapsulation for OLEDs: Evaluation of Multi‐layer Barriers using the Ca Test

We report on a method to evaluate thin film barriers for direct encapsulation of OLEDs. Based on the corrosion of reactive metal films and modeling thereof, this method is used to quantify the water permeation rate of high-performance diffusion barriers. This method was first used to measure the barrier properties of flexible plastic substrates for display applications [1]. In the present work the system has been automated for improved repeatability and optical calibration has been performed to assess the sensitivity. Effective water vapor transmission rates down to 10−6 g/m2/day can be detected. Permeation data on a multi-layer thin film encapsulant was obtained at three temperatures. To demonstrate compatibility in the application, the same thin film encapsulant was used to package actual passive matrix devices. This is the first report of a quantitative measure of an OLED compatible thin film encapsulant.