OLED Substrate with Concave Light Trapping Microstructures

The patent applies curvature by forming concave microstructures on the substrate surface. These concave regions cause light to undergo multiple reflections and refractions, changing its propagation path from straight-line modal loss to scattered trajectories that can escape the substrate-air interface, thereby improving light extraction efficiency while maintaining a relatively simple overall substrate structure

The patent introduces micro-scale dimensional features (concave microstructures) on the substrate surface to address the macro-scale problem of light extraction. By adding this micro-dimensionality, light interacts with the surface topology rather than just the planar interface, enabling enhanced extraction without fundamentally changing the substrate's basic structure

The patent performs preliminary actions by first forming the concave microstructures on the metal foil surface through oxidation and etching before depositing the functional OLED layers. This preliminary structuring of the substrate allows subsequent layers to be deposited on a pre-configured surface that will actively manage light extraction, rather than adding complexity after device assembly

The patent replaces complex mechanical or lithographic patterning methods with an electrochemical approach. By using electrochemical oxidation to form metal oxide layers followed by selective etching, the concave microstructures are created through chemical processes rather than mechanical machining or complex photolithography, simplifying the overall manufacturing process