Abstract: A system for laser scanning a relatively movable reflective surface element and inspecting that surface by monitoring the reflected energy in both light and dark channel receivers. Flaws occurring on the surface of the element, depending on the types of flaws, cause various frequency components to be present in the reflected energy and affect the amount of energy reflected to the light and dark channel receivers. Circuitry is included to detect and classify the various types of flaws as they are scanned, to compute the condition of the inspected element and to grade that inspected element as being in an acceptable state or in one of a plurality of unacceptable states. The described reflective surface element is a silicon wafer of the type used as the base substrate in fabricating integrated circuits and other electronic components.

Abstract: A flying spot scanner is utilized to scan a beam of laser radiation along a fixed spacial path on a moving web material. An optical detector assembly is positioned to receive radiation reflected from individual elements of the web to produce an electrical signal which is processed to determine and monitor the number of the individual web elements per unit length.