| 摘要 |
PURPOSE:To provide a thin film for optical parts having the optical characteristic and mechanical strength equivalent to or better than the MgF2 vapor- deposited film, with no need for high-temp. treatment and capable of being used for plastic lenses, etc., without hindrance. CONSTITUTION:The thin film of this invention is formed with an inorg. compd. consisting of Mg, Si, O and F and contg. Si-F and Si-F bonds. The Si concn. in the thin film is preferably controlled to 3-10 wt.%. Since the refractive index and the absorption in the visible region are low, the thin film is of great use as the antireflection film. Besides, the crystal structure is dense, the thin film is excellent in durability and impact resistance, and hence a water-repellent org. film need not be provided. |
