| 摘要 |
PURPOSE:To enable accurate detection of a foreign matter existing on the surface to be inspected by scanning the surface of an object being inspected with a light beam spot to monitor a scattering light. CONSTITUTION:A laser light from a laser oscillator 14 is focused in the center of a galvanomirror 17 oscillating in a triangular wave via a plarization plate 16 and a condenser lens 15. After totally reflected therefrom, the laser light enters the surface of a foreign matter attachment prevention film 23 slantly as laser spot via a collimater lens 18. The laser spot scans over the surface of the foreign matter attachment prevention film 23 at a fixed speed. The laser spot on the scan line 22 forms an image on a one-dimensional linear sensor 27 through a polaroid prism 25 and an image formation lens 26 to be detected. Induction takes place on the one-dimensional linear sensor 27 at each reflection position of the laser spot and a detection signal is outputted corresponding to the position of the induction. |
