Linescan apparatus for detecting salient pattern of a product

摘要

A linescan apparatus for detecting salient pattern on a surface of a product comprises: a laser light source for continuously emitting a laser beam; a polygon mirror for reflecting the laser beam; a drive for rotating the polygon mirror to scan said laser beam; an f theta lens arranged such that the linescan laser beam strikes against the plane perpendicularly; a carrying device for moving the product in the direction substantially perpendicular to the plane; a mirror for reflecting the linescan laser beam reflected at a surface of the product to direct the linescan laser beam to the polygon mirror through the f theta lens, the mirror being positioned apart from the second plane; and a beam position detector for detecting unidimensional position of a spot mede by the linescan laser beam projected thereon from the mirror via the polygon mirror. This linescan apparatus provides three-dimensional data of a surface of the product. The detected position signal is compared by reference data for inspecting the product. An linescan apparatus further comprises second beam position detector and an averaging circuit for averaging outputs from first mentioned and second beam detectors.