| 摘要 |
A rotation detector includes a rotary disk (20) in which slits (22) are recorded, and a photodetector (10) for reading the slits (22) with a laser beam (15). The slits are constituted by concave and convex parts having different widths radially formed on one surface of the rotary disk at different intervals. The width of one of the concave and convex parts constituting the slits (22) which has a smaller width or slit interval is set to be smaller than the spot size of the laser beam. |
