| 摘要 |
<p>An improved high sensitivity optical inspection system (10) for detecting flaws on a diffractive surface (12) containing surface patterns includes: a first and a second illumination means (26, 31a, 31b) for illuminating predetermined regions (22) on the diffractive surface to generate a scattered intensity distribution (35, 36, 37) in response to either a flaw or a surface pattern; means for detecting the intensity level of the scattered intensity distribution at a plurality of locations about the diffractive surface; means for establishing a minimum detected intensity level; means, responsive to the minimum detected intensity level, for indicating the absence of a flaw on the illuminated region of the diffractive surface when the minimum detected intensity level is below a threshold intensity level and for indicating the presence of a flaw on the illuminated region of the diffractive surface when the minimum detected intensity level exceeds the threshold intensity level; and means for moving (18) the diffractive surface to generate a scan pattern on the diffractive surface to inspect the entire surface.</p> |
