| 摘要 |
PURPOSE:To obtain a metallic reflecting mirror having high reflectivity, lightness and high accuracy by coating a pure metal or the like on the surface of a light alloy or a material of low thermal expansion and machining the surface to a specular surface. CONSTITUTION:An Al material of high purity is coated on the outside circumference of a rotary polyhedral mirror base plate 1 consisting of an Al alloy having high tensile strength and the outside circumferential surface thereof is machined to a specular surface. A material having the property suited for the light reflection characteristics of the wavelength used is selected for the material 2 and the treating stage for increasing reflectivity is omitted simply by forming a protective film 3 for the specular surface after formation of the specular surface by machining. |
