An optical sheet includes a transparent substrate. The optical sheet further includes light-scattering elements randomly and nonperiodically distributed in the transparent substrate. Each light-scattering element of the light scattering elements includes a binding-material member and light-scattering particles dispersed in the binding-material member. A weight percent calculated from dividing a total weight of light-scattering particles of the light-scattering elements by a total weight of the light-scattering elements is in a range of 5 wt % to 40 wt %.