Patent ID: 7586595

Claim:
A method of scanning an information recording medium that has a plurality of resin layers and a plurality of information layers, which are separated by the respective resin layers, laminated on at least one surface of a substrate, the method scanning the respective resin layers for defects and comprising: an image capture step of emitting scanning light toward the one surface at a predetermined incident angle from a fixed position on the one surface side, rotating the information recording medium in a fixed direction, and simultaneously receiving reflected light for the scanning light at a fixed position on an optical path of the reflected light to capture images at predetermined time intervals; a counting step of counting a number of images of a same defect that have been captured in the image capture step; and a specifying step of specifying that an (N−1)-th resin layer counting from the substrate side is a resin layer in which the defect is present when the counted number of images is N, where N is a natural number of two or higher.