A system for inspecting a printed circuit board constituted by an insulating board having a conductive pattern thereon which creates interconnections between circuit elements mounted on the board. In this system, a laser beam is deflected in the X and Y directions to generate a raster scan which is optically...http://www.google.de/patents/US4269515?utm_source=gb-gplus-sharePatent US4269515 - Electro-optical system for inspecting printed circuit boards
