| 摘要 |
PURPOSE:To eliminate the need for optical and electric corrections and to easily and accurately detect a defect by photodetecting reflected or transmitted light from a planar body to be detected through a light transmissive member. CONSTITUTION:Laser light emitted by the light source 12 of a light irradiation system 11 is converged by a condenser lens 13 to illuminate the planar body 41 through the optical scanner 15 of an optical scanning means 14. When the planar body 41 is transparent or opaque, the reflected light LR or transmitted light Lr of the scanning light LS is incident on the light incidence part 22 of the transparent member 21 made of a glass or plastic rod, etc. The incident light LR or Lr is scattered in the member 21 and incident on a photodetection system 31. If the planar body 41 has a defect, the photodetection level of the photodetector 32 of a detection part 31 varies and the defect is detected accurately through the arithmetic processing of a detecting device 33. |
