Ultraviolet absorbing film provided on a surface of an optical element and use thereof for reducing internal reflections

Abstract

An ultraviolet absorbing film, a light absorbing film, an optical element, an optical unit, and a light illuminating apparatus are disclosed. The ultraviolet absorbing film is provided on at least one surface of an optical element to reduce internal reflections therein and includes a transition metal oxide of a transition metal selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ce, and combinations thereof that contains no organic constituent. The ultraviolet absorbing film is formed by a process including applying an ultraviolet absorbing paint including an oxide precursor of the transition metal on at least one surface of the optical element; and a binder component or a solvent in which the oxide precursor is dissolved; and heating the coating to a predetermined temperature at which the oxide precursor forms the transition metal oxide and the binder or the solvent substantially completely decomposes or volatilizes.