Roughened Interface Light-Emitting Structure for Angular Color Shift Reduction

The patent applies local quality by creating a roughened interface at a specific location within the light-emitting structure (between the substrate and cover layer) rather than uniformly roughening all surfaces. This localized roughening provides scattering exactly where needed to extract trapped light, while leaving other interfaces smooth to maintain color accuracy and avoid inter-pixel cross-talk.

The patent changes the surface roughness parameter of the interface between substrate and cover layer to an RMS roughness of 1-50 nm. This controlled parameter change creates weak scattering that extracts light without the strong scattering effects that degrade color gamut and increase cross-talk, thus resolving the contradiction between light extraction efficiency and color accuracy.

The roughened interface is localized to the substrate-cover layer interface, creating scattering only in this specific region. This localized approach extracts light that would otherwise be trapped without causing broad angular emissions that lead to inter-pixel cross-talk, as the scattering is confined to a specific spatial location rather than occurring throughout the entire light-emitting structure.

The patent converts the potentially harmful effect of scattering (which can cause cross-talk) into a beneficial effect by using weak scattering from a roughened interface with controlled RMS roughness of 1-50 nm. This weak scattering is sufficient to extract trapped light but too weak to cause significant inter-pixel cross-talk, thus converting what could be a harmful effect into a beneficial one.