Light guide plate and image display device

Abstract

To improve image quality by increasing light use efficiency and the like. Provided is a light guide plate including an incidence diffraction grating that diffracts incident light into the light guide plate, a substrate that internally and totally reflects the light diffracted into the light guide plate by the incidence diffraction grating and guides the light, an expansion diffraction grating that diffracts and expands the light guided by the substrate, and an emission diffraction grating that diffracts the light diffracted by the expansion diffraction grating and projects the light into the pupils of an observer, wherein the expansion diffraction grating includes at least two regions that are a first region and a second region in front view, the sum of a grating vector provided for the incidence diffraction grating, a grating vector provided for the expansion diffraction grating, and a basic grating vector provided for the emission diffraction grating is 0, and the grating vector of the diffraction grating having the highest diffraction efficiency among the diffraction gratings provided for the first region is provided in a different direction from the grating vector of the diffraction grating having the highest diffraction efficiency among the diffraction gratings provided for the second region.

Dependencies are inferred from the claim text.