Method and apparatus for inspection of a substrate by use of a ring illuminator
AssigneeTRW Inc.
InventorsMau-Song Chou, Richard A. Chodzko, L. Suzanne Casement, Jonathan W. Arenberg
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Abstract
A method and apparatus for the inspection of a substrate provides consistent detection of defects such as cracks, differentiates between different types of defects, and, does not excessively heat the substrate. An infrared radiating source produces infrared energy which illuminates the substrate in a uniform manner at an incident angle. An infrared camera collects a portion of the infrared light which is reflected from the substrate. An image is created from the collected light which includes indicia of the defect. The image is examined as the incident angle is varied for changes in the appearance of the indicia.
Claims22
An apparatus for detecting a defect in a substrate comprising:
- an infrared radiating source spaced from said substrate and positioned to substantially uniformly illuminate said substrate with infrared light,
- an infrared camera with a lens positioned to collect reflected infrared light from said substrate;
- and,
- means for creating an image from said reflected infrared light, said image including indicia representative of said defect.
A method for detecting a defect in a substrate comprising the steps of:
- illuminating said substrate with an infrared light source in an approximately uniform manner,
- collecting reflected infrared light from said substrate,
- producing an image from said reflected infrared light;
- and,
- examining said image for indicia representative of said defect.
An apparatus for detecting defects in a substrate and for determining a type of said defect:
- an infrared radiating source spaced from said substrate and positioned to substantially uniformly illuminate said substrate with infrared light at an incident angle,
- an infrared camera with a lens positioned to collect reflected infrared light from said substrate;
- and,
- means for creating an image from said reflected infrared light, said image including indicia representative of said defect;
- and,
- means to change said incident angle.
A method for detecting a defect in a substrate and for determining at type of said defect comprising the steps of:
- illuminating said substrate with an infrared light source in an approximately uniform manner at an incident angle;
- collecting reflected infrared light from said substrate;
- producing an image from said reflected infrared light;
- examining said image for indicia representative of said defect;
- and,
- varying said incident angle while continuously monitoring said image for changes in the appearance of the indicia.
Dependencies are inferred from the claim text.