Linear displacement laser interferometer calibration method and device based on three-standard-optical-axis air bath

Abstract

The invention provides a linear displacement laser interferometer calibration method and a linear displacement laser interferometer calibration device based on three-standard-optical-axis air bath, and belongs to the technical field of laser measurement. A measuring light beam of a laser interferometer to be calibrated passes through a middle through hole of a three-axis hollow laser interference mirror group, and is parallelly arranged in the center position of three parallel standard measuring light beams distributed in a regular triangular prism side edge form; the vertical distance from the standard measuring light beams to the measuring light beam of the laser interferometer to be calibrated is very small, the differences of environment interference degrees of the three standard measuring light beams and the measuring light beam of the laser interferometer to be calibrated are very small, and the air refractive index average value of the three standard measuring light beams is approximate to the air refractive index value of the measuring light beam of the laser interferometer to be calibrated; through the stable air bath environment formed by an air bath device, the air temperature, the humidity and the air pressure are approximate to uniform distribution, so the air refractive index average value of the three standard measuring light beams is more approximate to the air refractive index value of the measuring light beam of the laser interferometer to be calibrated.

Description

Technical field [0001] The invention belongs to the technical field of laser measurement, and mainly relates to a laser interferometer calibration method and device. Background technique [0002] Laser interferometer measurement of linear displacement technology is a high-precision standard measurement technology, widely used in precision and ultra-precision machining, microelectronics equipment, nanotechnology industrial equipment and national defense equipment, in order to ensure the accuracy of laser interferometer measurement of linear displacement , A scientific and effective linear displacement laser interferometer calibration method and device are needed. The general idea of ​​calibrating a linear displacement laser interferometer is to use a linear displacement laser interferometer with a higher accuracy level for calibration. When the accuracy of the two is similar, it is called a comparison. In the actual calibration work, most of the linear displacement laser interfer...

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Problems solved by technology

Since the two sets of laser interferometers are placed in parallel, the two paths of light are similarly affected by the environment, and the refractive index of air has little influence on the two paths of light. Big error

[0004] figure 2 It is a schematic diagram of the face-to-face laser interferometer calibration device. The standard measuring mirror and the calibrated measuring mirror are installed on the moving platform face to face. The advantage is that the measuring beam axes of the two sets of laser interferometers can be adjusted to almost the same measuring axis. The Abbe error is very small, and the disadvantage is that the near end of one interferometer is the far end of the other, the optical paths of the two are not equal, and the interference of the environment is different. inconsistent

[0005] In 2011, the National Institute of Metrology established the first 80-meter long-length laser interferometer measurement device in China (Leng Yuguo, Tao Lei, Xu Jian. Analysis of the accuracy and influencing factors of the dual-frequency laser interferometer system based on the 80-meter measurement device. Metrology and Testing Technology, 2011,38(9):47-49), the standard device used is to place three Agilent5530 long-distance dual-frequency laser interferometers in parallel to form a three-way laser interferometer, and the calibrated laser interferometer The instrument is placed between them for calibration and calibration. This scheme is a derivative of the parallel calibration method, and since three-way light is used for simultaneous measurement, it can compensate for the Abbe error during measurement. However, since three lasers are placed in parallel Therefore, the spatial position of the three-way standard measurement light is relatively far away, and the distance between the measurement light of the calibrated laser interferometer and each standard measurement light is also relatively long. All measurement light paths are affected by the environment differently, and the air refractive index has inconsistent effects on all measurement light paths. , making or inaccurate calibration measurements

Since the two sets of laser interferometers share one interferometer group and measuring mirror, it is impossible to determine whether the shared interferometer group and measuring mirror belong to the standard laser interferometer part or the calibrated standard laser interferometer part. Therefore, it is not exactly two sets Calibration of the laser interferometer for calibration

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