| 摘要 |
PURPOSE:To obtain the IR transmissive material capable of transmitting an IR of about 10 mum wavelength almost without any reflection and advantageously applicable to optical parts, window material, etc., by coating a zinc sulfide substrate with a cerium fluoride film. CONSTITUTION:The material consists of a zinc sulfide substrate 1 and cerium fluoride coatings 2 on the substrate 1. Namely, the refractive index of the antireflection coating for the zinc sulfide (ZnS) substrate 1 has to be controlled close to the square root of that of the substrate, and cerium fluoride (CeF3) is appropriately used as the hard coating material transmitting an IR of about 10 mum wavelength. Consequently, the antireflection effect is produced especially in the vicinity of 10 mum wavelength, the wavelength region transmitting >=90% of an IR is widened, and the material is effectively used as an IR broad-band transmissive material. |
