| 摘要 |
PURPOSE:To obtain a preventive film which is effective to light in a wide ultraviolet range by employing a four-layer structure consisting of materials which differ in refractive index from an incidence medium side to a substrate side. CONSTITUTION:The four-layer structure consists of a 1st layer 1 which has a lower refractive index than the lens substrate 5, a 2nd layer 2 which has a 1.5-1.8 refractive index and is made of an intermediate refractive index material, a 3rd layer 3 made of a low refractive index material having a lower refractive index than the substrate 5, and a 4th layer made of an intermediate refractive index material whose refractive index is 1.5-1.8 successively from the incidence medium side. Consequently, this structure functions effectively to light in a 160-400nm wide ultraviolet range. |
