Apparatus for surface inspection

摘要

This apparatus permits the non-destructive examination of entire surfaces for defects and contamination, and can detect microscopically small dot-shaped and linear defects and extremely fine macroscopic non-homogeneous areas. For this purpose, an astigmatic lens system (5) is placed in the optical path between light source (2) and objective (9) which produces a cigar-shaped intermediate image (31), in which the feed offset in scanning the surface (10) depends on the intermediate image (31) and is equal to the length of the intermediate image (31) projected upon this surface (10). A dark-field stop assembly (18) with an adjustable dark-field deflection system (8) is placed in the optical path between the lens system (5) and the objective (9), which projects the light beam (1) after deflection exactly centered at right angles through the objective (9) upon the surface of the object (10). The light reflected by the surface (10) and collected by the objective (9) is projected to a photo detector. An electronic analysis system (21) breaks down the amplified output signals from the photo detector (19) into measured values due to dot-shaped, linear, and planiform defects. The electronic analysis system (21) is connected via a computer unit (22) to peripheral equipment (23, 24, 25) which permits the representation of all the measured values obtained in a measuring cycle.