| 摘要 |
PURPOSE:To detect foreign matter on the same reference level, by illuminating an object to be inspected by a plurality of illumination light sources linearily arranged and detecting the scattering light image of the foreign matter within the illumination region by a lens array wherein minute image forming lenses are arranged on a straight line. CONSTITUTION:This detector is constituted of illumination light sources 4 irradiating the surface of the foreign matter adhesion preventing film 2 adhered to a glass substrate 1, a lens array 5 and a photoelectric converter element 7. The foreign matter 12 on the surface of the film 2 is detected over a wide range by a large number of image forming lenses 16 arranged at the place upwardly spaced apart from the film 2 and the foreign matter image 18 is projected on the light receiving surface of the element 7 and the electric signal generated corresponding to light receiving intensity is compared with a reference level and judged to detect the foreign matter. Since a plurality of the light source 4, a plurality of the lenses 16 and the element 7 are respectively arranged linearily, the foreign matter can be detected on the same reference level at the center and periphery of the surface of the film 2. |
