| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for detecting defects on a surface of a plate which detects the defects in the plate, the minor irregularity in the plate and a region in which the linear irregularity extends regardless of a difference between reflection coefficients on the surface of the plate. SOLUTION: The invention includes the method for detecting the defects on the surface of the plate which irradiates the surface of the transparent or translucent plate with a light, and detects the defects by processing an image obtained by an imager for imaging the reflection light. The method for detecting the defects in the plate uses a light emitting means having a frequency cut filter and a diffraction mask installed in the front of a lens for collecting the light. The center position of the light transmitted through the frequency cut filter and the diffraction mask is shifted from the center of the defect detection region in the plate as an object by a distance from one third or more to a half or less of a viewing field of the imager. COPYRIGHT: (C)2008,JPO&INPIT
|
