| 摘要 |
PROBLEM TO BE SOLVED: To provide a flaw inspecting method and its device for an insulating film covered steel sheet capable of distinguishing the flaws of a lower insulating nontransparent film layer and an upper insulating transparent film layer respectively and inspecting them with a high flaw detection capability. SOLUTION: A covered steel sheet surface formed with the lower insulating nontransparent film layer and the upper insulating transparent film layer is illuminated, the covered steel sheet surface is photographed by an image pickup device to inspect the flaws of the film layers by this flaw inspecting method. The covered steel sheet surface is illuminated at the angle of polarization or an angle near it, and the reflected light from the covered steel sheet surface is photographed by a first image pickup means 21 via a polarization filter 22 at the regular reflection angle or an angle near it and photographed by a second image pickup device 24 via a polarization filter 25.
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