| 摘要 |
PURPOSE:To detect accurately defects such as cracks and scratches on the surface of a body by combination of at least two optical elements having condensing property with a reflecting mirror arranged in the middle of these elements. CONSTITUTION:The reflecting mirror 3 is placed at a prescribed position in relation to the 2nd convex lens 2 and one to one image thereof is formed at a point 6 apart therefrom at the same distance on the opposite side. And, parallel incident rays 7 in the 1st convex lens 1 are converged at the focus 5 of the 1st convex lens 1 and the diameter of the rays becomes minimum. The ray reflected by the reflecting mirror 3 is refrected by the 2nd convex lens 2 and forms an image of beam waist at a point 8. This optical system being employed for the light-projecting device 10, normal reflected ray 12 and a irregularly reflected ray 14 are detected by detectors 11, 13 and 13' and the ratio of the luminous energy of normal reflection to that of irregular reflection is found by an operation device 15, whereby the presence and absence of defects on the surface of a body A to be inspected are discriminated. |
