| 摘要 |
PURPOSE:To obtain a water-repellent optical member excellent in durability and wear resistance by forming a magnesium fluoride film by sputtering the outermost layer exposed to air. CONSTITUTION:This optical member has an antireflection film formed on a specified glass substrate 1. This antireflection film consists of an Al2O3 film 2 having lambda/4 thickness, ZrO3 film 3 having lambda/2 thickness and MgF2 film 4 having lambda/4 thickness (lambda: 500nm) successively formed by vacuum vapor deposition. Further, a MgF2 film 5 is formed to 10nm thickness as the outermost layer on the MgF2 film 4 by magnetron suputtering to constitute the optical member. In the MgF2 film 5 formed by sputtering, part of MgF2 is dissociated by the effect of plasma during sputtering and the surface of the film 5 has (-F) radicals produced by dissociation. Thus, high water repellent property is obtd. by forming the MgF2 film as the outermost layer by sputtering. |
