REFLECTANCE-TYPE DIFFUSION PLATE, DISPLAY DEVICE, PROJECTION DEVICE, AND ILLUMINATION DEVICE

To achieve more uniform diffusion angle distribution properties.A reflective diffuser plate according to the present invention is a microlens array reflective diffuser plate including a single lens group positioned on a surface of a transparent base material. There are variations in aperture diameter and radius of curvature that respective single lenses constituting the single lens group have in the single lens group as a whole, and vertex positions of the respective single lenses are located irregularly. A luminance distribution of reflected light of light vertically incident on the single lens group is substantially uniform in a predetermined diffusion angle range. For at least either light incident on the single lens group from a direction that forms an angle of 20 degrees with a surface normal direction of the transparent base material or light incident on the single lens group from a direction that forms an angle of 40 degrees with the surface normal direction of the transparent base material, a relation of 0.3 ≤ A/B ≤ 1 holds where A represents a reflection luminance value in the surface normal direction, and B represents a peak reflection luminance value of a diffuse reflection component.