| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a latent defect due to fluctuation in rotation, etc., of a part of an information recording medium where a data synchronizing signal is recorded. SOLUTION: Defect inspection based upon whether data synchronism can be detected is carried out by using a data synchronizing signal 52 which is longer by fluctuation in rotation before and after a data synchronizing signal 52 in normal reproduction of recording information including its retrial. A case wherein data synchronism can not be detected is detected as a defect by using the longer data synchronizing signal 57 to detect even a defect which is present at a position off the position of the conventional short data synchronizing signal 52 and neglected before like a defect 41 of a recording medium 11 and a defect 43 of a recording medium 13 during defect inspection since the data synchronizing signal 52 is reproduced normally, and consequently latent defects 41 and 43 which are elicited meeting the position of the data synchronizing signal 52 owing to the fluctuation in rotation, etc., of a recording medium can securely be detected to realize highly accurate defect inspection wherein the fluctuation in rotation of the recording medium is taken into consideration. COPYRIGHT: (C)2003,JPO
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