Patent ID: 6072582
Filing Date: 2000-06-06
Classification: G01B

Abstract:
A displacement measuring method, comprising the steps of:dividing incident light into a first and second beams;causing the first beam to be reflected by a surface to be measured and causing said second beam to be reflected by a reference surface;producing an image of interference fringes caused by light reflected by said surface to be measured and light reflected by said reference surface, said image of interference fringes including a monochromatic-light image and a chromatic-light image which are simultaneously photographed;detecting a position of a zero-order interference fringe based on a maximum brightness position of said chromatic-light image; andmeasuring the displacement of a position to be measured, based on the position of an interference fringe in said monochromatic-light image which corresponds to the position to be measured, and the position of an interference fringe in said monochromatic-light image which corresponds to the zero-order interference fringe.