PHOTORESIST MASK/SMOOTHING LAYER ENSURING THE FIELD HOMOGENEITY AND BETTER STEP-COVERAGE IN OLED DISPLAYS

摘要

A method of making an organic light emitting device (OLED) is disclosed wherein an inert insulating conformal smoothing layer is deposited over a protruding structure. The smoothing layer is patterned to expose portions of the structure underlying the smoothing layer and defining active regions of the device. The inert smoothing layer is treated, preferably by heat reflow, to taper the layer over the stepped edges of the structure on the exposed portions. Additional layers are then deposited over the smoothing layer and the exposed portions of the structure. The smoothing layer blunts all underlying layer edges and provides sloped edges wherever a step occurs from one layer to another. This effect results in a homogeneous field across the pixel and the continuity in the layers deposited after the photoresist layer.