REFLECTING MIRROR FOR LIGHT BEAM SCANNER, AND MANUFACTURING METHOD THEREFORE

摘要

PROBLEM TO BE SOLVED: To form a reflecting surface layer having high surface precision, by depositing a plated layer on a surface of a mirror substrate and grinding the plated layer and thereby to form a reflecting mirror which enables optical scanning at a high speed and high precision to be performed of a nontoxic material. SOLUTION: The mirror substrate 11 constituting the reflecting mirror 10 is formed of a magnesium alloy which is a material having light weight and rigidity durable to operation and the reflecting surface layer 12 is formed on a surface of the mirror substrate 11. As the reflecting surface layer 12, a plated layer is formed by nickel-phosphor plating or nickel-phosphor-boron plating which is hard material with hardness >=500 Hv Vickers hardness, and then the plated layer is subjected to grinding processing of high precision to set to 30 to 20μm thickness. Thereby the reflecting mirror 10 as a whole will not become heavy-weight and the plated layer as a reflecting surface having high surface precision of <=0.4λreflects laser beams in the precise direction.