Apparatus for detecting electrostatic surface potential

摘要

A set of birefringent members disposed in a path of light has an input surface via which the light enters the set and an output surface via which the light exits from the set. The birefringent members are designed and arranged so that the light separates into an ordinary ray and an extraordinary ray after the light enters the set via the input surface, that the ordinary ray and the extraordinary ray proceed along different courses respectively in the set, and that the ordinary ray and the extraordinary ray meet together where the ordinary ray and the extraordinary ray exit from the set via the output surface.