| 摘要 |
PURPOSE:To obtain the highly accurate apparatus for measuring the size and the defect of a planar body. CONSTITUTION:Two light beams, which are scanned in the first optical system, are made to be the parallel beams through telecentric F/theta lenses 71 and 72. The light beams are cast on a planar body from the opposite directions on the same optical axis. Therefore, the passed lights and the reflected lights of the incident light beams in both directions pass the telecentric F/theta lenses 71 and 72 again. The light beams are converged and cast into detecting means 81-84 through pairs of beam splitters 51-56. Therefore, the output signals of the detecting means 81-84 indicate the surface state of the upper surface and the rear surface of the planar body 1 and the presence or absence of an opening. When the output signals are processed, the size, the defect and the like can be measured. |
