INSPECTION SYSTEM EMPLOYING ILLUMINATION THAT IS SELECTABLE OVER A CONTINUOUS RANGE ANGLES

摘要

An illumination device and method for inspecting objects having microscopic features is provided. The device includes an illuminator which provides a solid angle of angularly specific illumination defining an illumination angle, selected by a user from among a continuous range of possible illumination angles. The device further includes an object inspector which inspects the object illuminated by the illuminator. The illuminator may include an illumination source, a light concentrator, an illumination angle selector, disposed along a light path between the illumination source and the object inspector. The illumination angle selector may have a first position in which directly -reflected light propagates toward the object plane and a second position in which no light both selected by the illumination angle selector and directly reflected from the object plane enters the collecting lens. Rather, in the second position, only scattered light from the object plane enters the collecting lens.