| 摘要 |
PURPOSE:To prevent ghosts and flares when this antireflection film is applied on a glass lens by forming the antireflection film into the 7-layered constitution provided on a glass substrate having from 1.5 to 1.8 refractive index, forming this constitution of the 1st layer and the 2nd layers, successively counted from the substrate, in such a manner as to satisfy specific conditions and further forming the 6th layer of a mixture contg. ZrO2 and TiO2. CONSTITUTION:The antireflection film has the 7-layered constitution provided on the glass substrate having from 1.5 to 1.8 refractive index and is constituted to satisfy the conditions expressed by equations I to VII when the layers are designated as the 1st layer and the 2nd layer successively counted from the substrate. Further, the 6th layer is formed of the mixture composed of the ZrO2 and TiO2. If the equations I to VII, lambda0 denotes the design wavelength selected in a 450 to 550nm range; ni denotes a refractive index; nidi denotes an optical film thickness; (i) denotes an integer from 1 to 7. The surface reflectivity in the wavelength range of a visible ray region is lowered in this way when the antireflection film is provided on the glass lens. An excellent antireflection effect is thus obtd. The ghosts and flares are eliminated and the lens is particularly adequately usable as a spectacle lens. |
