Patent ID: 7724358
Filing Date: 2010-05-25
Classification: G01N

Abstract:
1. An illuminator for dark field inspection of a surface of a target, comprising: a plurality of illumination arms disposed about an illumination region, each arm having an input end and an output end, the output end outputting substantially uniform diverging light; a plurality of turning elements each having a first face optically coupled to the respective output ends of the respective illumination arms, and a second face having optical power in a meridional direction; a plurality of anamorphic elements each having a first optical power in an azimuthal direction and a second optical power in the meridional direction, the first and second optical powers being unequal, and the anamorphic element being optically coupled to the second face of the turning element; and wherein light from the illuminator that is incident on the illumination region is substantially uniform in its angular spectrum.