Tsinghua University

Rujin Han

Yu Zhu

Jinchun Hu

Wensheng Yin

Rong Cheng

Dengfeng Xu

Ming Zhang

Chang Tian

A high-resolution phase detection method and system based on a plane grating laser interferometer. The method uses a dual-frequency interferometer to measure the displacement, and the measurement signal processing comprises an integral part and a decimal portion, a phase equation set of a displacement measurement signal is constructed according to a measurement optical path principle of a heterodyne plane grating laser interferometer; a non-linear equation set for which the unknowns are instantaneous phase, interval phase and signal amplitude is established; and the equation sets above are solved by using the least squares method, so as to realize phase discrimination, thereby realizing precise displacement measurement. The method can solve the problems in the traditional time measurement-based phase detection technology, such as low measurement accuracy, and failing to satisfy small measuring range measurement. The measurement method can be applied to systems such as precision manufacturing equipment and lithography machine.

High-resolution phase detection method and system based on plane grating laser interferometer

Growing community of inventors

Beijing, China

Rujin Han