| 摘要 |
PURPOSE:To obtain the line inspection method in which the quality and the yield of a glass substrate for a magnetic recording medium or a liquid-crystal display plate are enhanced. CONSTITUTION:Before a magnetic film or the like is formed on a substrate 1, the outward appearance of the substrate 1 is inspected by an automatic transmission-type outward-appearance inspection apparatus 6. That is to say, a laser beam from a laser light source 12 is shone at the substrate 1 via a collimator 13, a polygon mirror 14 and a Fourier lens 15, and a transmitted beam is receibed by sensors 17, 18 via a Fourier lens 16, a detection signal by the sensors 17, 18 is thresholdprocessed by a comparator or the like, it is then taken into a computer, it is changed into a two-dimensional image, the image is processed, and the existence of a flaw is discriminated. |
