| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical multilayer film having high resistance to light in an ultraviolet region irradiated at a high environmental temperature and including a blue laser.SOLUTION: In the optical multilayer film formed on a plastic substrate, each layer of the optical multilayer film is formed of oxide or oxynitride, and layers adjacent to each other are formed of a material having a different refractive index. Oxidation-reduction potential of elements forming the oxide or the oxynitride is -0.9 V or less; the thickness of a first layer contacted with the substrate is 10 nm or more; a difference of refractivity at the wave length of 400 nm between a material of the substrate and a material forming the first layer is 0.2 or less; a difference of refractivity at the wave length of 400 nm between two kinds of materials forming the adjacent layers is 0.45 or less; and the total thickness of the optical multilayer film is 3000 nm or less. |
