CN103528525B - Three-optical axis compensation and air bath type linear displacement laser interferometer calibration method and device - Google Patents

Abstract

The invention discloses a three-optical axis compensation and air bath type linear displacement laser interferometer calibration method and a three-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 three-axis hollow laser interference mirror group, and are arranged in parallel at the central positions of three 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 three 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 three 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

Three optical axis compensation and air bath linear displacement laser interferometer calibration method and device

technical field

The invention belongs to the technical field of laser measurement, and mainly relates to a laser interferometer calibration method and device.

Background technique

Laser interferometry linear displacement technology is a standard measurement technology with high precision. It is 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 , requires a scientific and effective linear displacement laser interferometer calibration method and device. The general idea of calibrating a linear displacement laser interferometer is to use a linear displacement laser interferometer with a higher level of precision for calibration. When the accuracy of the two is similar, it is called comparison. In the actual calibration work, most of the linear displacement laser interferometers have considerable precision, so the calibration of the linear displacement laser interferometer is realized by comparison. At present, the general calibration methods of linear displacement laser interferometers include parallel, face-to-face and common optical path (Liao Qing, Zhu Xiaoping, Wang Weichen, Du Hua. Research on the calibration method of laser interferometer length measurement accuracy. Modern measurement and laboratory management, 2005, 1:6-7).

Figure 1 is a schematic diagram of the parallel laser interferometer calibration device. The standard measuring mirror and the calibrated measuring mirror are installed on the same movable platform. When the moving platform moves, the optical path of the two sets of laser interferometer measuring beams increases and decreases simultaneously. Small. 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. Bay error is large.

Figure 2 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 of the latter 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 impact.

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. , resulting in inaccurate calibration measurements.

Figure 3 is a schematic diagram of the structure of the common optical path laser interferometer calibration device. The difference between the common optical path type and the parallel laser interferometer calibration device is that the two lasers and the receiver are bent at 90 degrees, and the two sets of laser interferometers share the same interference mirror group. and measuring mirrors. 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 The calibration of the laser interferometer is calibrated.

In 1985, Dr-Ing H.-H.Schussler made full use of the spatial distribution (Dr-Ing H.-H.Schussler. Comparison and calibration of laser interferometer systems. Measurement, 1985, 3(4): 175-184), and multi Common optical path calibration of the linear displacement laser interferometer. Since only the number of common optical path laser interferometers is increased, this method also has the disadvantages of the common optical path laser interferometer calibration device mentioned above.

Contents of the invention

In view of the relatively large Abbe error, serious inconsistency of the air refractive index and the inaccurate calibration of two sets of laser interferometers in the existing linear displacement laser interferometer calibration device, the present invention proposes and develops three optical axis compensation and Air bath linear displacement laser interferometer calibration method and device, the invention makes the vertical distance between the standard measuring beam and the calibrated laser interferometer measuring beam very small, thereby reducing the Abbe error and the influence of air refractive index inconsistency, And in the accurate sense, two sets of laser interferometers are calibrated.

The object of the present invention is achieved through the following technical solutions:

A method for calibrating a three-optical-axis compensation and an air-bath linear displacement laser interferometer, the steps of which are as follows:

(1) The output light of the standard laser interferometer laser passes through the three-axis hollow laser interference mirror group to form three standard measurement beams parallel to each other. The three standard measurement beams are incident on the plane mirror with the middle hole in the form of regular triangular prism side edge distribution. After the part of the light with plane mirror displacement information in the standard measurement beam is reflected back to the three-axis hollow laser interference mirror group, according to the three interference signals corresponding to the three standard measurement beams obtained from the three-axis hollow laser interference mirror group, it can be Obtain three displacement values of the plane mirror with the middle hole moving along the direction of the standard measuring beam, and the remaining part of each standard measuring beam is transmitted to the three beam position detectors through the plane mirror with the middle hole;

(2) The output light of the calibrated laser interferometer laser passes through the calibrated laser interferometer interferometer group to form the calibrated laser interferometer measurement beam, and the calibrated laser interferometer measurement beam passes through the middle through hole of the three-axis hollow laser interferometer group , which are parallel to the three standard measuring beams and are at the same distance from each standard measuring beam. The measuring beam of the calibrated laser interferometer is incident on the mirror of the calibrated laser interferometer, and after being reflected back to the interferometer group of the calibrated laser interferometer , according to the interference signal obtained from the calibrated laser interferometer interferometer group, the displacement value of the calibrated laser interferometer mirror moving along the direction of the standard measurement beam can be obtained;

(3) The air bath device blows a uniform airflow along the direction perpendicular to the three standard measuring beams to form a stable air bath environment. On the plane perpendicular to the three standard measuring beams, an equilateral triangle formed by the projection points of the three standard measuring beams on the plane In the area, the air bath environment makes the air temperature, humidity and air pressure approximately uniform, so that the average value of the air refractive index of the three standard measuring beams is closer to the value of the air refractive index of the calibrated laser interferometer measuring beam;

(4) The initial incident position coordinates of the three standard measuring beams and the calibrated laser interferometer measuring beam on the incident surface of the target mirror are (x ₁ , y ₁ ), (x ₂ , y ₂ ), (x ₃ , y ₃ ) and (x ₄ , y ₄ ), after the coordinates of the initial incident position of each measurement beam on the incident surface of the target mirror go through the coordinate displacement (x, y) in the two-dimensional direction, due to the shape of the reflective surface of the target mirror The displacement measurements caused by the features are functions z ₁ (x ₁ +x,y ₁ +y), z ₂ (x ₂ +x,y ₂ +y), z ₃ (x ₃ +x,y ₃ +y) and z ₄ (x ₄ +x,y ₄ +y);

(5) During the reciprocating movement of the moving table along the direction of the standard measuring beam, there is a derivative displacement in any two-dimensional direction perpendicular to the plane of the standard measuring beam, and the three measuring displacements of the standard laser interferometer are sampled synchronously at a uniform or non-uniform sampling rate The value and the measured displacement value of the calibrated laser interferometer are respectively S ₁ , S ₂ , S ₃ and S ₄ , and the three beam position detectors simultaneously detect the position of the three standard measuring beam spots on the incident surface of the target mirror in the two-dimensional direction Derived coordinate displacement value, calculate the arithmetic mean value (x', y') of the three coordinate displacement values as the derived coordinate displacement value of each measurement beam, and compensate the displacement measurement error caused by the topographical characteristics of the reflective surface of the target mirror to In the measured displacement value, S ₁ -z ₁ (x ₁ +x', y ₁ +y'), S ₂ -z ₂ (x ₂ +x', y ₂ +y'), S ₃ -z ₃ ( x ₃ +x', y ₃ +y') and S ₄ -z ₄ (x ₄ +x', y ₄ +y'), take S ₁ -z ₁ (x ₁ +x',y ₁ +y' ), S ₂ -z ₂ (x ₂ +x', y ₂ +y') and S ₃ -z ₃ (x ₃ +x', y ₃ +y') mean and S ₄ -z ₄ (x ₄ +x', y ₄ +y') to get a number of sampling measurement error values.

A three optical axis compensation and air bath linear displacement laser interferometer calibration device, including a standard laser interferometer laser and three receivers arranged at positions that can receive the interference signals of the standard laser interferometer, the wires connect the three receivers to the Standard laser interferometer signal processing system connection; a three-axis hollow standard laser interferometer group with a middle through hole on the output optical path of the standard laser interferometer laser that allows the calibrated laser interferometer measurement beam to pass through; a three-axis hollow standard laser A guide rail is arranged on one side of the interference mirror group, and the moving table is fitted on the guide rail. A plane mirror with a middle hole is installed on the moving table, and a calibrated laser interferometer mirror is installed in the middle hole of the plane mirror. The calibrated laser interferometer mirror and the The plane mirror with the middle hole constitutes the target reflector whose incident surface is coplanar and whose relative position is fixed; the three beam position detectors are arranged behind the transmission area of the plane mirror with the middle hole, and are respectively located on three parallel standard measurement beam transmission optical paths; The air bath device is arranged on the side of the standard measurement beam; the calibrated laser interferometer interferometer group and the calibrated laser interferometer laser are arranged on the other side of the three-axis hollow standard laser interferometer group, and the calibrated laser interferometer interferometer group is located at The output optical path of the calibrated laser interferometer laser; the calibrated laser interferometer receiver is arranged at a position that can receive the calibrated laser interferometer interference signal, and the wire will be calibrated The laser interferometer receiver and the calibrated laser interferometer signal processing system connect.

The present invention has following characteristics and good effect:

(1) Compared with the parallel laser interferometer calibration device, since the measured beam of the calibrated laser interferometer passes through the middle through hole of the three-axis hollow laser interferometer group, the distance between the measured optical axis of the calibrated laser interferometer and the parallel standard optical axis The vertical distance of the two laser interferometers is shorter, and the optical paths of the two are closer, so the Abbe error is very small when the two sets of laser interferometers are calibrated.

(2) Compared with the face-to-face laser interferometer calibration device, in the plane perpendicular to the three standard measuring beams, in the equilateral triangle area formed by the projection points of the three standard measuring beams on the plane, the three standard measuring beams and the calibrated The difference in the degree of interference of the laser interferometer measurement beam by the environment is small, and the average value of the air refractive index of the three standard measurement beams is close to the value of the air refractive index of the calibrated laser interferometer measurement beam.

(3) Compared with the common optical path laser interferometer calibration device, there is no shared interferometer group and measuring mirror, and the ownership of the standard laser interferometer components and the calibrated standard laser interferometer components is clear. It is accurate to calibrate two sets of laser interferometers .

(4) The three beam position detectors can measure the derivative displacement of the three standard measuring beams relative to the target mirror in any two-dimensional direction perpendicular to the standard measuring beam plane. The measurement displacement error is compensated to the linear displacement measurement result to ensure the accuracy of the linear displacement measurement value.

(5) In the equilateral triangle area perpendicular to the plane of the three standard measuring beams and surrounded by the projection of the three standard measuring beams on its plane, a stable air bath environment formed by the air bath device arranged on the side of the three parallel standard measuring beams The air temperature, humidity and air pressure are approximately uniformly distributed, so that the average value of the air refractive index of the three standard measuring beams is closer to the value of the air refractive index of the calibrated laser interferometer measuring beam.

Description of drawings

Figure 1 is a schematic diagram of the parallel laser interferometer calibration device

Figure 2 is a schematic diagram of the face-to-face laser interferometer calibration device

Figure 3 is a schematic diagram of the calibration device of the common optical path laser interferometer

Figure 4 is a schematic diagram of the three optical axis compensation and air bath linear displacement laser interferometer calibration device

Figure 5 is a schematic diagram of spot position distribution on the incident surface of the target mirror composed of a plane mirror with an intermediate hole and a calibrated laser interferometer mirror

In the figure: 1 standard laser interferometer laser, 2 three-axis hollow standard laser interferometer group, 3, 4, 5 three parallel standard measuring beams, 6 plane mirror with middle hole, 7, 8, 9 standard laser interferometer receiver, 10 standard signal processing system, 11 calibrated laser interferometer laser, 12 calibrated laser interferometer interferometer group, 13 calibrated laser interferometer measurement beam, 14 middle through hole, 15 calibrated laser interferometer mirror, 16 calibrated Laser interferometer receiver, 17 calibrated laser interferometer signal processing system, 18 motion stage, 19 guide rail, 20 air bath device, 21, 22, 23 three beam position detectors, 24, 25, 26 three parallel standard measuring beams The spot position, 27 is calibrated to the spot position of the beam of the laser interferometer.

Detailed ways

The specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

A three-optical axis compensation and air bath linear displacement laser interferometer calibration device, including a standard laser interferometer laser 1 and three receivers arranged at positions that can respectively receive interference signals corresponding to three parallel standard measurement beams 3, 4, and 5 The wires connect the three receivers 7, 8, 9 to the standard laser interferometer signal processing system 10 respectively; if the output optical path of the standard laser interferometer laser 1 is provided with an intermediate through hole 14, it can be used Calibrate the three-axis hollow standard laser interference mirror group 2 through which the laser interferometer measuring beam 13 passes; one side of the three-axis hollow standard laser interferometer group 2 is equipped with a guide rail 19, and the moving platform 18 is fitted on the guiding rail 19, and on the moving platform 18 A plane mirror 6 with a middle hole is installed, and a calibrated laser interferometer reflector 15 is installed in the middle hole of the plane mirror 6. The calibrated laser interferometer reflector 15 and the plane mirror 6 with a middle hole form a target whose incident surface is coplanar and relatively fixed. Mirror; three beam position detectors 21, 22, 23 are arranged behind the transmission area of the plane mirror 6 with a middle hole, and are respectively located on the transmission light paths of the three parallel standard measurement beams 3, 4, 5; on the side of the three parallel standard measurement beams An air bath device is arranged on the inside; the calibrated laser interferometer interferometer group 12 and the calibrated laser interferometer laser 11 are arranged on the other side of the three-axis hollow standard laser interferometer group 2, and the calibrated laser interferometer interferometer group 12 is located at On the output optical path of the calibrated laser interferometer laser 11; the calibrated laser interferometer receiver 16 is configured at a position that can receive the calibrated laser interferometer interference signal, and the wire will be calibrated The laser interferometer receiver 16 and the calibrated laser interferometer A signal processing system 17 is connected.

The three parallel standard measuring beams 3, 4, 5 and the calibrated laser interferometer measuring beam 13 are all perpendicular to the incident surface of the target reflector.

The middle through hole 14 of the three-axis hollow standard laser interference mirror group 2 includes any shape, and the number is one or more than one.

Each of the parallel standard measuring beams 3, 4, 5 and the calibrated laser interferometer measuring beam 13 are reflected once or more by the plane mirror 6 with a middle hole and the calibrated laser interferometer mirror 15 respectively.

The laser interferometer reflector 15 to be calibrated includes a plane mirror, a corner cube prism, and a right-angle prism.

A method for calibrating a three-optical-axis compensation and an air-bath linear displacement laser interferometer, the steps of which are as follows:

(1) The output light of the standard laser interferometer laser 1 passes through the three-axis hollow laser interference mirror group 2 to form three standard measurement beams 3, 4, 5 parallel to each other, and the three standard measurement beams 3, 4, 5 are distributed in the side edges of a regular triangular prism The form is incident on the plane mirror 6 with a middle hole, and part of the light with the displacement information of the plane mirror 6 in each standard measuring beam is reflected back to the three-axis hollow laser interference mirror group 2, according to the three-axis hollow laser interference mirror group 2 The obtained three interference signals corresponding to the three standard measuring beams 3, 4, and 5 respectively can obtain three displacement values of the plane mirror 6 with the middle hole moving along the directions of the standard measuring beams 3, 4, and 5, and each standard measuring beam 3, 4, 5, the rest of the light is transmitted to the three beam position detectors 21, 22, 23 through the plane mirror 6 with a middle hole;

(2) The output light of the calibrated laser interferometer laser 11 passes through the calibrated laser interferometer interferometer group 12 to form the calibrated laser interferometer measurement beam 13, and the calibrated laser interferometer measurement beam 13 passes through the three-axis hollow laser interferometer group The middle through hole 14 of 2 is parallel to the three standard measuring beams 3, 4, and 5, and is equal to the distance from each standard measuring beam. The calibrated laser interferometer measuring beam 13 is incident on the calibrated laser interferometer reflector 15, After being reflected back to the interferometer group 12 of the calibrated laser interferometer, according to the interference signal obtained from the interferometer group 12 of the calibrated laser interferometer, it can be obtained that the mirror 15 of the calibrated laser interferometer along the standard measurement beam 3, 4, The displacement value of the movement in 5 directions;

(3) The air bath device 20 blows a uniform airflow along the directions perpendicular to the three standard measuring beams 3, 4, and 5 to form a stable air bath environment. The beams 3, 4, and 5 are in the equilateral triangle area formed by the projection points of the plane, and the air bath environment makes the air temperature, humidity and air pressure approximately uniform, making the average value of the air refractive index of the three standard measuring beams 3, 4, and 5 more accurate. Close to the air refractive index value of the calibrated laser interferometer measuring beam 13;

(4) The initial incident position coordinates of the three standard measuring beams 3, 4, 5 and the calibrated laser interferometer measuring beam 13 on the incident surface of the target mirror are (x ₁ , y ₁ ), (x ₂ , y ₂ ), (x ₃ , y ₃ ) and (x ₄ , y ₄ ), after the coordinates of the initial incident position of each measurement beam on the incident surface of the target mirror go through the coordinate displacement (x, y) in the two-dimensional direction, due to the target The measured displacement values caused by the topography of the reflective surface of the mirror are functions z ₁ (x ₁ +x,y ₁ +y), z ₂ (x ₂ +x,y ₂ +y), z ₃ (x ₃ +x ,y ₃ +y) and z ₄ (x ₄ +x,y ₄ +y);

(5) During the reciprocating movement of the moving table 18 along the standard measuring beam 3, 4, 5 directions, there is a derivative displacement in any two-dimensional direction perpendicular to the standard measuring beam 3, 4, 5 plane, at a uniform or non-uniform sampling rate , the three measured displacement values of the standard laser interferometer and the measured displacement values of the calibrated laser interferometer are sampled synchronously, respectively S ₁ , S ₂ , S ₃ and S ₄ , and the three beam position detectors 21, 22, 23 detect synchronously The derived coordinate displacement values of the three standard measurement beam spots on the two-dimensional direction on the incident surface of the target mirror, and the arithmetic mean value (x', y') of the three coordinate displacement values is calculated as the derived coordinate displacement value of each measurement beam, Compensate the displacement measurement error caused by the topographical features of the reflective surface of the target mirror into the measured displacement value, and obtain S ₁ -z ₁ (x ₁ +x', y ₁ +y'), S ₂ -z ₂ (x ₂ + x', y ₂ +y'), S ₃ -z ₃ (x ₃ +x', y ₃ +y') and S ₄ -Z ₄ (x ₄ +x', y ₄ +y'), take S ₁ -z ₁ (x ₁ +x', y ₁ +y'), S ₂ -z ₂ (x ₂ +x',y ₂ +y') and S ₃ -z ₃ (x ₃ +x', y ₃ +y') and S ₄ -z ₄ (x ₄ +x', y ₄ +y') as a difference to obtain several sampling measurement error values.

The spot positions 24, 25, and 26 of the standard measuring beams are respectively the positions where the three parallel standard measuring beams 3, 4, and 5 are incident on the plane mirror 6 with a middle hole, and the beam spot position 27 of the calibrated laser interferometer is measured by the calibrated laser interferometer. The position where the light beam 13 is incident on the mirror 15 of the calibrated laser interferometer can be seen from the position distribution. The measuring beams 3 , 4 , 5 will be clamped centrally by the calibration laser interferometer measuring beam 13 .

Claims (6)

1. three optical axis compensations and a gas bath type linear displacement laser interferometer calibration method, is characterized in that the method step is as follows:

(1) the output light of standard laser interferometer laser instrument forms through three axle hollow laser interference mirror groups three the canonical measure light beams be parallel to each other, article three, canonical measure light beam incides on the level crossing of interstitial hole with regular triangular prism incline distribution form, after being reflected back toward three axle hollow laser interference mirror groups with the part light of level crossing displacement information in every bar canonical measure light beam, according to three interference signals corresponding respectively with three canonical measure light beams obtained from three axle hollow laser interference mirror groups, three shift values that the level crossing that can obtain interstitial hole moves along canonical measure beam direction, the remainder light of every bar canonical measure light beam is transmitted on three light-beam position detectors through there being the level crossing of interstitial hole,

(2) the output light being calibrated laser interferometer laser instrument is calibrated laser interferometer measurement light beam through being calibrated the formation of laser interferometer interference mirror group, be calibrated the intermediate throughholes of laser interferometer measurement light beam through three axle hollow laser interference mirror groups, parallel with three canonical measure light beams, and it is equal with the distance of every bar canonical measure light beam, be calibrated laser interferometer measurement light beam to incide and be calibrated on laser interferometer catoptron, after being reflected back toward and being calibrated laser interferometer interference mirror group, according to from being calibrated the interference signal obtained in laser interferometer interference mirror group, can obtain being calibrated the shift value that laser interferometer catoptron moves along canonical measure beam direction,

(3) gas bath device is along blowing uniform speed airflow perpendicular to three canonical measure beam directions, form stable gas bath environment, in the plane perpendicular to three canonical measure light beams, by three canonical measure light beams in the equilateral triangle region that this plane projection point is formed, gas bath environment makes air themperature, humidity and air pressure approaches uniformity distribute, and makes the air refraction mean value of three canonical measure light beams more close to the air refraction value being calibrated laser interferometer measurement light beam;

Article (4) three, canonical measure light beam is respectively (x with the original incident position coordinates being calibrated laser interferometer measurement light beam respective on the target mirror plane of incidence ₁, y ₁), (x ₂, y ₂), (x ₃, y ₃) and (x ₄, y ₄), on the target mirror plane of incidence, the original incident position coordinates of every bar measuring beam is after the coordinate displacement (x, y) of two-dimensional directional, and the displacement measurement caused because of target mirror reflecting surface shape characteristic is respectively function z ₁(x ₁+ x, y ₁+ y), z ₂(x ₂+ x, y ₂+ y), z ₃(x ₃+ x, y ₃+ y) and z ₄(x ₄+ x, y ₄+ y);

(5) sports platform along in canonical measure beam direction reciprocatory movement with in the derivative displacement perpendicular to random two-dimensional direction in canonical measure beam plane, with at the uniform velocity or non-at the uniform velocity sampling rate, synchronized sampling standard laser interferometer three is measured shift value and is calibrated laser interferometer measurement shift value, is respectively S ₁, S ₂, S ₃and S ₄the synchronizing detection of three light-beam position detectors is to the derivative coordinate displacement value of three canonical measure beam and focus two-dimensional directional on the target mirror plane of incidence, ask for three coordinate displacement values arithmetic mean (x ', y ') as the derivative coordinate displacement value of every bar measuring beam, the displacement measurement errors that target mirror reflecting surface shape characteristic causes is compensated to and measures in shift value, obtain S ₁-z ₁(x ₁+ x ', y ₁+ y '), S ₂-z ₂(x ₂+ x ', y ₂+ y '), S ₃-z ₃(x ₃+ x ', y ₃+ y ') and S ₄-z ₄(x ₄+ x ', y ₄+ y '), get S _1-z ₁(x ₁+ x ', y ₁+ y '), S ₂-z ₂(x ₂+ x ', y ₂+ y ') and S ₃-z ₃(x ₃+ x ', y ₃+ y ') mean value and S ₄-z ₄(x ₄+ x ', y ₄+ y ') poor, obtain some sampled measurements error amounts.

2. an optical axis compensation and gas bath type linear displacement laser interferometer calibrating installation, comprise standard laser interferometer laser instrument (1) and three be configured in the receiver (7,8,9) that can receive on standard laser interferometer interference signal position, three receivers (7,8,9) are connected with standard laser interferometer signal disposal system (10) by wire respectively; It is characterized in that being configured with can allowing of intermediate throughholes (14) on standard laser interferometer laser instrument (1) output light path and be calibrated three axle hollow standard laser interference mirror group (2) that laser interferometer measurement light beam (13) passes; Three axle hollow standard laser interference mirror group (2) side arrangement guide rail (19), sports platform (18) is fitted on guide rail (19), sports platform (18) is provided with the level crossing (6) of interstitial hole, install in level crossing (6) interstitial hole and be calibrated laser interferometer catoptron (15), be calibrated laser interferometer catoptron (15) and have the level crossing of interstitial hole (6) the composition plane of incidence coplanar and the target mirror that relative position is fixing; Three light-beam position detectors (21,22,23) are configured in after level crossing (6) regional transmission of interstitial hole, and lay respectively on three parallel standards measuring beams (3,4,5) transmitted light path; At three parallel standards measuring beams (3,4,5) sidepiece configuration gas bath device (20); Be calibrated laser interferometer interference mirror group (12) in three axle hollow standard laser interference mirror group (2) opposite sides configurations and be calibrated laser interferometer laser instrument (11), described in be calibrated laser interferometer interference mirror group (12) and be positioned at and be calibrated on laser interferometer laser instrument (11) output light path; Being calibrated laser interferometer receiver (16) is configured on the position that can receive and be calibrated laser interferometer interference signal, and wire will be calibrated laser interferometer receiver (16) and be calibrated laser interferometer signal disposal system (17) and be connected.

3. three optical axis compensations according to claim 2 and gas bath type linear displacement laser interferometer calibrating installation, is characterized in that described three parallel standards measuring beams (3,4,5) and to be calibrated laser interferometer measurement light beam (13) all vertical with the target mirror plane of incidence.

4. three optical axis compensations according to claim 2 and gas bath type linear displacement laser interferometer calibrating installation, it is characterized in that the intermediate throughholes (14) of three described axle hollow standard laser interference mirror group (2) comprises arbitrary shape, number is one or more.

5. three optical axis compensations according to claim 2 and gas bath type linear displacement laser interferometer calibrating installation, is characterized in that described every bar parallel standards measuring beam (3,4,5) and is calibrated laser interferometer measurement light beam (13) had the level crossing of interstitial hole (6) respectively and be calibrated more than laser interferometer catoptron (15) reflection once or once.

6. three optical axis compensations according to claim 2 and gas bath type linear displacement laser interferometer calibrating installation, is characterized in that the described laser interferometer catoptron (15) that is calibrated comprises level crossing, prism of corner cube, right-angle prism.