| 摘要 |
PURPOSE:To shorten an inspection time by diffusing a laser beam over a prescribed angle range, irradiating a disk to be inspected, condensing it, and thereafter, fetching it successively by a scanner, and executing an inspection. CONSTITUTION:A defect of the surface of a disk 1 is inspected by irradiating a laser beam from a laser light source 10, to the disk 1, and detecting a reflected beam from the disk 1, by a photodetector. The laser beam is diffused over a prescribed angle range on one plane, the diffused laser beam is irradiated simultaneously on a radius of the disk 1, and its reflected laser beam is condensed on one point by a lens 12. From this condensed beam, the reflected laser beam of each point on the radius is selected and fetched successively by a scanner 19, supplied to a photoelectric multiplier 13 through mirrors 20, 21, and a defect of the surface on the disk 1 can be inspected. |
