| 摘要 |
PROBLEM TO BE SOLVED: To provide a periodicity determination method and a device capable of attaining high-accuracy period determination, and to provide a method for manufacturing a sheet-like object.SOLUTION: In the periodic defect detection method, a conveyed sheet-like object is irradiated with a light, and a reflected light or a transmitted light via the sheet-like object is received, and defects of the sheet-like object are detected, based on the received light; and it is determined whether the defect is a periodic defect generated periodically. In the periodic defect detection method, a defect characteristic quantity range is set in each process for manufacturing the sheet-like object, and a sheet width direction tolerance, or the sheet width direction tolerance and a sheet conveyance direction tolerance are set in each process, to thereby perform a period determination. |
