Straightness measuring interferometer system and measuring method without nonlinear error

Abstract

The invention provides a straightness measurement interferometer system without nonlinear errors and a measurement method. A heterodyne light source adopts light emitted by a monostable frequency laser light source, and a polarization direction is divided into two beams of light through a spectroscope, and the two beams of light pass through two acoustic optical modulators respectively and then are changed into two beams of spatially separated light with different frequencies. The two beams of light pass through a Koesters prism and then are divided into four light beams which are propagated in parallel and are symmetrical in space. The four light beams pass through an interferometer system consisting of a half-wave plate, a combined polarization beam splitting prism, a quarter-wave plate,a wedge angle prism and a wedge surface reflector; when the wedge-angle prism generates straightness displacement in a horizontal direction, optical path information (or phase information) of the twobeams of measurement light is changed, and the straightness error of the wedge-angle prism can be obtained by comparing phase difference changes of the two beams of measurement light signals. According to the method provided by the invention, high-precision measurement of a micro straightness error can be realized.

Description

technical field [0001] The invention relates to the technical field of micro-nano measurement and measurement, in particular to a high-precision measurement interferometer and a measurement method for small straightness errors. Background technique [0002] Advanced manufacturing technology, as one of the priority themes of the national medium and long-term scientific and technological development outline, has become a key research object of the manufacturing industry. At present, the displacement control accuracy of various precision positioning devices is generally on the order of nanometers, but in high-performance precision CNC machine tools and three-coordinate measuring machines, the displacement measurement accuracy has reached several nanometers, or even less than 1 nanometer. The continuous improvement of displacement accuracy requirements means that various deviations in the displacement process must be precisely measured and controlled. In the measurement of mult...

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Problems solved by technology

However, due to the phenomenon of frequency aliasing in this system, there is a nonlinear error in the measurement results, which can reach more than a dozen nanometers or even tens of nanometers, which severely limits the detection accuracy of straightness errors.

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