Diffraction grating heterodyne two-dimensional displacement measuring system and diffraction grating heterodyne two-dimensional displacement measuring method

Abstract

The invention provides a novel diffraction grating displacement measuring system which comprises a double-frequency laser device, a numerical reading head, a one-dimensional measuring grating, a firstreceiver, a second receiver and a signal processing system. The numerical reading head is in a symmetric structural design; reference signals can be inputted into the signal processing system by thedouble-frequency laser device, and light with frequency difference and orthogonal linear polarization is emitted by the double-frequency laser device, is subjected to incidence into the numerical reading head and is split into reference light and measuring light in the numerical reading head; a left beam of measuring light and a right beam of measuring light are subjected to incidence onto the one-dimensional reflecting grating, diffraction light is generated on the one-dimensional reflecting grating. returns the numerical reading head according to original paths, interferes with a left beam of reference light and a right beam of reference light and is transmitted into the first receiver and the second receiver, and the signals are processed by the signal processing system to obtain displacement information of the one-dimensional measuring grating in grating vector directions and grating normal directions. The novel diffraction grating displacement measuring system has the advantages that displacement in the grating vector directions and the grating normal directions can be measured by the aid of the novel diffraction grating displacement measuring system, the measurement range fordisplacement in the grating normal direction can be expanded, and the novel diffraction grating displacement measuring system is simple in structure.

Description

technical field [0001] The invention belongs to the technical field of precise displacement measurement, and relates to a diffraction grating heterodyne type two-dimensional displacement measurement system and method. Background technique [0002] The diffraction grating displacement measurement system takes the grating pitch as the measurement benchmark, and adopts symmetrical order diffraction light interference to realize the displacement measurement. The optical path is symmetrical and the optical path is short. The displacement measurement system is less restricted by the environment and has good measurement repeatability. The points enable high-resolution and high-precision measurements. At present, diffraction grating displacement measurement systems mostly use one-dimensional measurement gratings to achieve one-dimensional displacement measurement. For two-dimensional displacement measurement, most of them use two-dimensional gratings to achieve two-dimensional displ...

AI Technical Summary

Problems solved by technology

At present, most of the diffraction grating displacement measurement systems use one-dimensional measuring grating to realize one-dimensional displacement measurement. For two-dimensional displacement measurement, most of them use two-dimensional grating to realize two-dimensional displacement measurement parallel to the grating plane. Some literatures use one-dimensional The grating realizes the two-dimensional displacement measurement of the grating vector and the normal direction of the grating, but the range of the normal direction of the grating is limited by the size of the spot size and the size of the optical element, and long-stroke measurement cannot be realized

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