Four-optical axis compensation and air bath type linear displacement laser interferometer calibration method and device

Abstract

The invention discloses a four-optical axis compensation and air bath type linear displacement laser interferometer calibration method and a four-optical axis compensation and air bath type linear displacement laser interferometer calibration device, and belongs to the technical field of laser measurement. Measurement light beams of a calibrated laser interferometer penetrate through a middle through hole of a four-axis hollow laser interference mirror group, and are arranged in parallel at the central positions of four parallel standard measurement light beams which are distributed as side edges of a regular triangular prism; the standard measurement light beams are at short perpendicular distances away from the measurement light beams of the calibrated laser interferometer, and an average air refractivity value of the four standard measurement light beams is approximate to air refractivity values of the measurement light beams of the calibrated laser interferometer; air temperature, air humidity and air pressure in a stable air bath environment formed by an air bath device are approximately uniformly distributed, so that the average air refractivity value of the four standard measurement light beams is more approximate to the air refractivity values of the measurement light beams of the calibrated laser interferometer; a measurement error caused by the surface appearance of the reflecting surface of a target reflector is compensated into a linear displacement measurement result to ensure the accuracy of a linear displacement measurement value.

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 interferometry linear displacement technology is a high-precision standard measurement technology, which is widely used in precision and ultra-precision machining, microelectronic 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 interferom...

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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. The disadvantage is that the near end of one interferometer is the far end of the other.

[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 Agilent 5530 long-distance dual-frequency laser interferometers in parallel to form a three-way laser interferometer, and the calibrated laser The interferometer is placed between them to perform calibration. This scheme is a derivative of the parallel calibration method, and since the three-way light is used for simultaneous measurement, it can compensate for the Abbe error during measurement, but because the three lasers are parallel Placement, so 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 affects all measurement light paths. inconsistent, resulting in 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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