Straightness interference measuring device insensitive to incident angle

Abstract

The invention provides a straightness interference measuring device insensitive to an incident angle. The device comprises an interferometer host system, a double Wollaston prism, a double-sided right-angle roof reflector and a detection receiving unit, the interferometer host system comprises a laser emission optical system, the laser emission optical system emits a measuring light beam, after passing through the double Wollaston prism, the light is divided into two beams of cross-polarized light, and the light is reflected by the double-sided right-angle roof ridge reflector and then returns to the detection receiving unit for analysis of interference signals, and relative distance information is obtained. The device has the beneficial effects that the double Wollaston prism is adopted as the straightness interference mirror, so that the incident light angle is not sensitive, and the measurement precision can be obviously improved especially in the verticality measurement application; a parallel light beam polarization element with the adjustable shearing difference is adopted, and the problem that an existing straightness interference measurement device has a measurement blind area can be solved.

Description

technical field [0001] The invention relates to a straightness interferometric device, in particular to a straightness interferometric device insensitive to incident angles. Background technique [0002] British patent 1409339 mentions a linearity interferometric device, which uses a single Wollaston prism to divide the laser beam along the optical axis into two laser beams whose vibration directions are orthogonal. The beams of the two laser beams are approximately symmetrical about the main optical axis. The two beams travel to the double-sided mirror and return to the original path, and recombine into one beam at the Wollaston prism, and return to the system along the main optical axis. The angle of the double-sided mirror is designed to match the beam splitting angle of the Wollaston prism. This system has obvious shortcomings. One is that the beam returns to the original path, which easily leads to an imbalance in the laser frequency stabilization, resulting in a decre...

AI Technical Summary

Problems solved by technology

The interference mirror of the existing straightness mirror group is relatively sensitive to the incident angle, and a small change in the incident angle can cause a large change in the beam splitting angle of the interferometer, resulting in a large difference in the straightness slope measured at different incident angles. It is difficult to guarantee the repeatability of the straightness measurement. Although the slope can be eliminated in the straightness measurement, when it is applied to the squareness measurement, the difference in the slope will be directly reflected in the squareness measurement error, resulting in an increase in the squareness measurement error and reliable data. decreased sex

[0006]2. The existing straightness interferometric measurement device has the problem of measurement blind area

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