DIFFRACTION GRATING, OPTICAL WAVEGUIDE APPARATUS, AND DISPLAY DEVICE
DIFFRACTION GRATING, OPTICAL WAVEGUIDE APPARATUS, AND DISPLAY DEVICE
Provided are a diffraction grating, an optical waveguide apparatus including the diffraction grating and a display device including the diffraction grating. The diffraction grating includes a substrate and microstructure units. The microstructure units are formed on the substrate and arranged at intervals in two dimensional directions. A pattern formed by the orthographic projection of a microstructure unit on the substrate includes a first closed pattern. The boundary of the first closed pattern is formed by a smooth closed curve such that the boundary has no sharp vertices. At least a first curve segment having a negative radius of curvature is present on the boundary such that at least one valley is formed on the boundary.