| abstract |
With this device, surfaces can be examined non-destructively and over their entire surface for defects and contamination, whereby microscopic small point or line-shaped defects as well as the finest macroscopic inhomogeneities are recorded. For this purpose, an astigmatic lens system (5) is arranged in the beam path between the light source (2) and the objective (9) , which generates a cigar-shaped intermediate image (31) . Depending on the intermediate image (31), the feed when scanning the surface (10 ) corresponds to the length of the intermediate image (31) projected onto this surface (10) . A dark field stop module (18) with an adjustable dark field deflection (8 ) arranged in the beam path between the lens system (5) and the objective (9) , directs the illuminating beam (1) after the deflection exactly at right angles through the objective (9) onto the Surface (10) . The light emitted by the surface (10) and collected in the objective (9) is directed onto a photodetector (19) . Evaluation electronics (21) break down the amplified output signals of the photodetector (19) into measured values which result from punctiform, line-shaped and flat-shaped defects. The evaluation electronics (21) are connected via a computing unit (22) to peripheral devices (23, 24, 25) , by means of which the entirety of all measurement values of a measurement can be displayed. |