Head-up display apparatus, screen member, manufacturing method thereof and image projecting method

摘要

A screen member diffuses a bundle of rays of light projected from a laser scanner such that the bundle of rays of light is guided to a viewing range. The screen member includes a plurality of optical elements. A surface of each optical element forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface. The optical elements are arranged in a lattice pattern at each corresponding pitch that is set to adjust a peak-to-peak interval of diffracted rays, which are formed in the viewing range by diffraction of the bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than a diameter of a pupil of the viewer.