| 摘要 |
PURPOSE:To increase the speed of film formation by forming at least either of high refractive index film layers of two layers having different refractive indices by reactive sputtering. CONSTITUTION:The 1st high refractive index film 12, the 1st low refractive index film 13, the 2nd high refractive index film consisting of the 1st film-like body 14a and 2nd film-like 14b and the 2nd low refractive index film 15 are successively formed on a transparent substrate 11 consisting of glass, etc., and having a large area. The film 14a is formed by using the reactive sputtering to 1.9-2.2 refractive index and the film 14b is formed by the same method to 2.2-2.5 refractive index. The use of Ta2O5, ZrO2 and In2O3 for the film 14a and the use of TiO2 for the film 14b are preferable. The forming speed of the films is increased by forming the film 14a consisting of the material having the higher sputtering rate to the larger thickness and the film 14b consisting of the material having the lower sputtering rate to the smaller thickness in the above-mentioned manner. In addition, the films having the larger area are formed uniformly at the lower cost. |
