A high precision displacement sensor based on dual-gratings interference

摘要

A novel displacement sensor with large range and high resolution and simple structure is introduced. The sensor is based on grating diffraction and interference principle. When a laser beam passes through two parallel diffraction gratings, diffraction and interference will happen and interference fringes will be generated, and fringe movement is corresponding to relative grating movement. As a result, displacement measurement can be realized by the fringe collection and analysis. An experimental configuration is built for testing, 10mm range with 10nm resolution are achieved.