Apparatus for visual inspection

Abstract

An apparatus is provided which reduces the dependency of the direction of polarization on channels of an image sensor so as to improve the sensitivity of inspection. In the apparatus, the direction of an illumination beam incident on a polarizing beam splitter is made to be substantially parallel to the longitudinal direction of a field of view of an image sensor projected on the polarizing beam splitter.

1 . A visual inspection apparatus comprising:
 a specimen stage for holding a specimen;   a light source;   a polarizing beam splitter;   an objective lens;   a quarter waveplate arranged between said polarizing beam splitter and objective lens;   an imaging optics; and   an image sensor, an illumination beam of light rays emitted from said light source being irradiated on the specimen held by said specimen stage via said polarizing beam splitter, quarter waveplate and objective lens and a reflection beam from said specimen being led to said imaging optics by way of said objective lens, quarter waveplate and polarizing beam splitter so as to be imaged on said image sensor,   wherein the illumination beam from said light source is rendered to be incident on said polarizing beam splitter in an incident direction which is substantially parallel to a channel direction of a field of view of said image sensor projected on said polarizing beam splitter, or the direction of an optical path extending from said polarizing beam splitter toward said imaging optics and ending in said imaging optical system is substantially parallel to said channel direction.   
     
     
         2 - 6 . (canceled)