Surface inspection apparatus and method
AssigneeGenCorp Inc.
InventorsChing-Chih Lee, James F. Roach
Life of this patent
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Abstract
An apparatus for inspecting a reflective surface of an article for defects includes a point light source for generally uniformly illuminating the entire surface of the article under inspection, and a diffusing screen for intercepting the light rays reflected from the surface under inspection of the article. The intercepted light rays produce a high resolution image on the screen consisting of bright and dark areas or spots corresponding to surface defects in the article under inspection.
Claims10
An apparatus for inspecting a reflective surface of an article for defects, said apparatus comprising:
- a) a point light source for illuminating said surface;
- b) a diffusing screen for intercepting reflected light rays from said surface, said diffusing screen and said light source being disposed on generally opposite sides of said surface, so that an image of a light intensity profile of said surface is produced on said screen;
- and
- c) turntable means for rotating the article, the surface of which is to be inspected, to change the direction from which incident light rays from the point light source impinge on the surface defects, said apparatus being free of optical means for focusing light rays emitted from the point light source.
A method of inspecting a reflective surface of an article for defects, said method comprising the steps of:
- a) positioning a point light source and a diffusing screen on generally opposite sides of the reflective surface under inspection;
- b) illuminating the surface under inspection with said point light source;
- c) intercepting reflected light rays from said illuminated surface with said diffusing screen, so that an image of a light intensity profile of said reflective surface is produced on said screen;
- and
- d) changing the orientation of the article to change the direction from which incident light rays from the point light source impinge on the surface defects, said method being free of utilizing means to focus the light rays emitted from the point light source.
Dependencies are inferred from the claim text.