Rare‐earth oxysulfide films with an intrinsic cathodoluminescent efficiency equivalent to that of the same material in powder form have been produced. These films withstood the maximum power density of the electron beam apparatus, 7 W/mm2, without damage or intensity saturation. An apparatus‐limited luminance of 4×104fL from a terbium‐activated lanthanum oxysulfide film using 12‐kV cathode‐ray excitation was measured. A multilayer film of lanthanum oxysulfide activated with Eu, Tb, and Tm was produced whose emission color is voltage dependent.