DEFECT DETECTING OPTICAL SYSTEM AND SURFACE DEFECT INSPECTING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a defect detecting optical system and a surface defect inspecting apparatus easily adjustable in detection sensitivity and capable of detecting a minute uneven defect. SOLUTION: A floodlight projection system irradiating a face plate with laser beam having a width in the direction right-angled to a main scanning direction to relatively scan the face plate, a light receiving system equipped with a light receiver having (n) (n: an integer of 2 or more) light receiving elements arranged in a right-angled direction to receive reflected light from the face plate and forming the images of the scanning positions of the face plate on (n) light receiving elements, a stripe pattern filter becoming reverse in the relation of transmission or shading in the light receiving elements adjacent on the left and right sides substantially from a central part in the light receiving surfaces of the light receiving elements inserted in the light receiving system and a detection circuit generating the detection signal corresponding to the difference between the light receiving quantities of the adjacent light receiving elements are provided. The central part is substantially irradiated with the reflected light from the surface of the face plate in a defect free case.