| 摘要 |
PURPOSE:To rearrange the photodetecting device simply even if the standard surface diffraction pattern of an object to be checked is changed, by arranging a lattice-form photodetecting box divided into small holes on the projection face of the diffraction pattern. CONSTITUTION:Laser light beam 1 is projected to object 7 to be checked by oscillating mirror 10, and laser beam of light 1 diffracted by object 7 is received through Fresnel lens 11 and screen 12 by photodetecting box 2. Further, this laser beam of light is received through optical fibers 5, which are inserted to small holes 6 of photodetecting box 2 selectively, by photodetector 3 and is inputted to amplifier 4. Photodetecting parts 131, 132 and 133 are so weighted that they correspond to the standard pattern, the discolored pattern, and the scratch pattern, respectively, and detection outputs of the diffraction pattern of object 7 are processed by logical operation circuits, respectively, to discriminate a good quality article, a discolored defect, a scratch defect, and so on. As a result, replacement of optical fibers is sufficient for coping with the change of the pattern of the object to be checked. |
