23‐2: Characterization of Directional Chromaticity of Cylindrically Curved OLED

Abstract

Bending a flexible OLED panel alters the optical structure of the panel resulting in change of optical characteristics. The effects of bending on the luminous intensity distribution were analyzed and the issues were extracted, and reported in the previous publications by the first author. However, the directional chromaticity characteristics of the OLED in bent states remained. In this paper we study the on‐axis and off‐axis chromaticity characteristics of the bent OLEDs in cylindrical states. The characteristics of two OLEDs that had barrier layer thicknesses of 100 nm and 150 nm are measured at cylindrically bend curvature radii of R0=∞ mm (planar state), R2=143 mm (cylindrically curved state) and R5=56. 7 mm (cylindrically curved state). The effect of bent curvature on the directional characteristics of cylindrical OLEDs, such as emission spectrum and chromaticity are measured at specified viewing directions. The results are evaluated and discussed for the cylindrically curved OLEDs in comparison with those of the OLEDs in planar state.