Self-collimating grating interferometer with high optical subdivision structure

Abstract

A high optical subdivision structure of an auto-collimation grating interferometer includes a grating scale, a first rectangular prism, a second rectangular prism, a third rectangular prism, a fourth rectangular prism, a fifth rectangular prism, a sixth rectangular prism, a first reflecting mirror, and a second reflecting mirror. The high optical subdivision structure of the auto-collimation grating interferometer enables a measurement light beam of the grating interferometer to be reflected back and forth between the grating scale with high diffraction efficiency and the reflecting mirror, and increases times that the measurement light beam is diffracted by the grating scale by fully utilizing the characteristic that the grating is easy to obtain the high diffraction efficiency at a Bragg angle.

Description

technical field [0001] The invention relates to a grating interferometer, in particular to a high optical subdivision structure of the self-collimating grating interferometer, which can greatly increase the optical subdivision multiple of the grating interferometer. Background technique [0002] There are currently two main types of instruments for micro-nano precision displacement measurement: laser interferometer and grating interferometer. Laser interferometer is based on wavelength and can obtain high resolution, but its application is limited because the wavelength is easily affected by factors such as environment and light source. The grating interferometer just makes up for the shortcomings of the laser interferometer. It uses the grating period as the reference, and the measurement results are basically not affected by the environment and wavelength. It has been widely used in processing machine tools, robots, biomedical and other fields. [0003] Whether it is a la...

AI Technical Summary

Problems solved by technology

In order to solve the problem of generally low optical subdivision multiples, the patented high subdivision high-density grating interferometer CN104613865A proposes to use a high subdivision prism so that the measurement beam is reflected by the grating scale multiple times to obtain high-magnification optical subdivision, but the high subdivision prism requires special The processing and process are complicated, and the adjustment of the optical path is difficult. The patent CN104729402A of the high optical subdivision grating interferometer based on the plane mirror proposes the function of directly using the plane mirror instead of the special prism. High, the patented high-resolution grating interferometer based on high-density gratings CN104729411A proposes to use double gratings to achieve high-magnification subdivision effects, which not only simplifies the complex manufacturing process, but also has the same incident angle of the measuring beam incident on the grating scale each time, reducing The requirements of the grating design are met, but because the measuring beam is diffracted by two high-density gratings, the energy loss of the measuring beam increases, which limits the increase in the optical subdivision multiple

Moreover, none of the patents of the above-mentioned high-resolution grating interferometer adopts the Bragg angle incident grating scale of the grating, and does not make full use of the highest characteristics of the grating at this angle.

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