| 摘要 |
PURPOSE:To obtain the specular surface of a rotary mirror with high reflection effciency and without stripping by coating the surface of a porous alumna ceramic with a thick metallic film then forming a desired thin metallic film at a uniform thickness. CONSTITUTION:An alumina ceramic revolving shaft 7 and polyhedral body part 8 of a rotary mirror 6 are monolithic, and a cylindrical hysteresis ring 10 is seured to the outside circumference in the lower part of a shaft 7. The plate-like part 8 is made in one body with the shaft 7 so as to intersect orthogonally with the axial center of said shaft, and the outside circumferential surface thereof has an exact polyhedral shape of a desired number of faces. The faces of mirror parts 5 are in parallel exactly with the axial center. A thick film 11 of, for example, an Mo-Mn alloy is formed on the faces of the mirror parts 9 and the top and bottom surfaces of the part 8; thereafter, the faces of the mirror parts 9 are lapped and flattened so as not to have inclination to the axial center. A thin Al film of a uniform thickness is formed thereon. The mirror surface which has high reflectivity and high adhesive strength and is free from stripping in spite of high speed rotation is thus obtd. |
