| 摘要 |
PURPOSE:To improve the oxidation resistance and surface mechanical strength of an antireflection film and to prolong the life by providing a three-layred structure consisting of an arsenic trisulfide film, a lead fluoride film and a zinc sulfide film formed successively on a KCl substrate. CONSTITUTION:An arsenic trisulfide film 1 having superior adhesion and insoluble in water is vapor-deposited on a potassium chloride substrate 4 as the 1st layer contacting with the substrate to 2.552-2.748mum optical thickness. A lead fluoride film 2 causing hardly absorption and having a low refractive index is vapor-deposited on the film 1 as the 2nd layer to 1.101-1.1855mum optical thickness, and a zinc sulfide film 3 insoluble in water and having chemical stability and superior mechanical strength is vapor-deposited on the film 2 as the 3rd layer to 1.1105-1.196mum optical thickness to obtain the desired antireflection film for potassium chloride. This antireflection film absorbs hardly CO2 laser light, has superior moisture resistance, and transmits well He-Ne laser light. |
