SYSTEM AND METHOD FOR THREE-DIMENSIONAL INSPECTION USING PATTERNED LIGHT PROJECTION

摘要

An inspection system (10) is used to obtain three-dimensional information pertaining to an article (12) having elements with specular surfaces, such as the solder balls on a BGA device. The system includes patterned light projector (20) which projects a pattern at an oblique angle ( alpha ) with respect to the plane of the article (12) and an image detector (24) disposed generally above the article (12). The light projector (20) includes an extended light source (30) and a light patterning member (32) disposed such that the light pattern is in focus in an image plane parallel to the plane of the article (12), satisfying the Scheimpflug condition. The spacing of the lines is preferably greater than a spacing or pitch of the specular elements. An image processor (26) is coupled to the image detector (24) to receive the image and measure the lateral shift of the lines to determine height information using triangulation.