Patent ID: 8501052
Filing Date: 2013-08-06
Classification: C04B,C23C,G11B

Abstract:
1. An optical interference film or a protective film of an optical information recording medium which is formed by performing DC sputtering to a target comprising titanium oxide as its main component, wherein the film includes titanium, oxygen and copper, content of Ti is 29.0% or higher and 34.0 at % or less and content of Cu is 0.003 at % or higher and 7.7 at % or less with the remainder being oxygen and unavoidable impurities, and ratio of oxygen component to metal components, O/(2Ti+0.5Cu), is 0.96 or higher, and wherein a refractive index of the film in a wavelength region of 400 to 410 nm is 2.60 or higher.