Ultrahigh-resolution interferometer measurement method and system based on phase shift gauge block

Abstract

The invention discloses an ultrahigh resolution interferometer measurement method and system based on a phase shift gauge block, and the method comprises the steps: placing an ultrahigh resolution interferometer and a preset phase gauge block in a heat preservation box, and introducing two kinds of frequency stabilization laser into the heat preservation box through a single-mode optical fiber; obtaining interference fringe data by adopting a five-step phase shift method, and adjusting the interference fringe data according to the laser wavelength to obtain adjusted data; acquiring environmental data containing the preset phasor block in the heat preservation box, and correcting the adjustment data by eliminating change influence based on the environmental data to obtain corrected data; determining the length of the preset phasor block according to the decimal number of the interference fringes and the integer series of the interference fringes under different wavelengths through a multi-wavelength decimal superposition method, obtaining the measurement data of the Korotkoff interferometer, carrying out the adaptive compensation of the phase shifter, correcting the length according to the uncertainty of the measurement data, and obtaining the phase of the Korotkoff interferometer. The output is a measurement result.

Description

Technical Field

[0001] The present invention relates to the field of measurement, and particularly to a method and system for measuring with an ultra-high resolution interferometer based on a phase-shifting block. Background Art

[0002] In the field of precision measurement, high-precision measurement of tiny dimensions is crucial for cutting-edge industries such as aerospace and semiconductor manufacturing. Traditional measurement techniques are limited by precision and environmental adaptability, and it is difficult to meet the stringent requirements of modern industry for measurements at the nanometer or even sub-nanometer level. As a high-precision measurement device, the Kerr interferometer has certain applications in length measurement. However, in a complex environment, the measurement results are easily affected by environmental factors such as temperature, air pressure, and humidity, resulting in a decrease in measurement accuracy. Moreover, its phase shifter will generate phase shift errors during long-term operation or environmental changes, further affecting the measurement accuracy.

[0003] With the development of technology, ultra-high resolution interferometric measurement techniques have gradually emerged. By precisely analyzing interference fringes, it can achieve high-precision measurement of tiny dimensions. However, existing ultra-high resolution interferometer measurement methods have deficiencies in data processing and environmental compensation. For example, the processing of interference fringe data is not precise enough, making it difficult to effectively separate the fractional and integer orders of interference fringes, resulting in measurement errors; the compensation mechanism for the comprehensive influence of environmental factors is imperfect, and it is unable to fully eliminate the influence of environmental changes on measurement results. Therefore, there is an urgent need to study a method for measuring with an ultra-high resolution interferometer based on a phase-shifting block to improve measurement accuracy and stability and meet the development needs of the modern precision measurement field. Summary of the Invention

[0004] The object of the present invention is to provide a method for measuring with an ultra-high resolution interferometer based on a phase-shifting block.

[0005] To achieve the above object, the present invention is implemented according to the following technical solution: The present invention includes the following steps: Place an ultra-high resolution interferometer and a preset phase block in an incubator, and introduce two frequency-stabilized lasers into the incubator through single-mode optical fibers; the ultra-high resolution interferometer includes the optical-mechanical system and the control system of the interferometer; the optical-mechanical system includes a beam expansion system, a phase shifter, an adjustable mirror, a turntable system, and a fringe acquisition system; Obtain interference fringe data using the five-step phase-shifting method, and adjust the interference fringe data according to the laser wavelength to obtain adjusted data; the interference fringe data includes the fractional part of the interference fringes and the integer order of the interference fringes; Obtain the environmental data of the incubator containing the preset phase block, and correct the adjusted data based on the environmental data by eliminating the influence of changes to obtain corrected data; the environmental data includes temperature, air pressure, humidity, and carbon dioxide content; Determine the length of the preset phasor block according to the fractional part of the interference fringes and the integer order of the interference fringes at different wavelengths by the multi-wavelength fractional coincidence method, obtain the measurement data of the Kerr interferometer, perform adaptive compensation on the phase shifter, correct the length according to the uncertainty of the measurement data, and output the corrected length as the measurement result; including: Calculate the length of the phasor block: where the number of wavelengths measured is a, the preset block length for the number of wavelengths a is , in millimeters, the integer order of the interference fringes for the number of wavelengths a is , the fractional part of the interference fringes for the number of wavelengths a is , the air refractive index for the number of wavelengths a is , the wavelength for the number of wavelengths a is .

[0006] Further, a method for obtaining interference fringe data by the five-step phase-shifting method includes: Within an interference period of 2π, the phase shift interval is π / 2 each time, and the phase shifts are 0, π / 2, π, 3π / 2, and 2π respectively, obtaining 5 interference fringe images. Use the five-step phase unwrapping algorithm to calculate the phase distribution map of the interference fringes and obtain the integer order of the interference fringes. The fringes of the block interference measurement include the block interference region, the flat crystal interference region, and the invalid region; where the invalid region refers to the non-effective points, various noise points, and the block boundary region in the interference pattern; the block region and the flat crystal region in the interference fringes are discontinuous, which is a discontinuous phase field; perform phase unwrapping on the interference fringes of the block surface and the flat crystal surface respectively, Take the center point of the block as the starting point M0 for unwrapping. Starting from M0, unwrap the phases of the 4 adjacent points in the up, down, left, and right directions to obtain the M1 phase; starting from M1, respectively unwrap the phases of the 4 adjacent points that have not been unwrapped in its up, down, left, and right directions to obtain the M2 phase, and so on, until all the points that have not been unwrapped in the block interference region are unwrapped, and output the phase. The expression is: where the intensity distribution of the interference fringes in the c-th step is , the background light intensity is , the fringe contrast is , the phase to be measured is , the intensity distribution of the interference pattern of the first phase is , the intensity distribution of the interference pattern of the second phase is , the intensity distribution of the interference pattern of the third phase is , the intensity distribution of the interference pattern of the fourth phase is , the intensity distribution of the interference pattern in the 5th phase is ; Select the center point area of the measuring surface of the gauge block and the corresponding flat crystal areas on both sides, and calculate the phase difference to obtain the interference fraction: where the distance between the center of the interference fringes on the gauge block surface and the center of the adjacent interference fringes on the flat crystal surface is h, the distance between the centers of two adjacent interference fringes on the flat crystal surface is f, and the interference fraction is .

[0007] Furthermore, the method for adjusting the interference fringe data according to the laser wavelength includes: Calculate the optical path difference: where the phase change of the interference fringe is , the optical path difference is , and the wavelength is ; Introduce two laser wavelengths and calculate the equivalent wavelength: where the equivalent wavelength is , the wavelength of laser 1 is , and the wavelength of laser 2 is ; Adjust the phase difference according to the equivalent wavelength, and the expression is: where the adjusted phase difference is ; Output the adjusted phase difference as adjusted data.

[0008] Furthermore, the method for obtaining the corrected data by correcting the adjusted data based on the environmental data by eliminating the influence of changes includes: Obtain the refractive index deviation caused by the environmental data and the change in temperature data, calculate the air refractive index through the standard equation, and calculate the wavelength of light in vacuum: where the wavelength of light in vacuum is , the wavelength of light in air is , the refractive index of the atmosphere is , and the refractive index deviation is ; Adjust the actual wavelength of the laser, and the expression is: where the adjusted actual wavelength of the laser is , and the refractive index of air under the conditions of temperature T, pressure P, humidity H, and carbon dioxide concentration C is ; The optical path difference is corrected according to the refractive index change, and the expression is: where the corrected optical path difference is , the speed of light is v; The calibration phase, the expression is: where the adjusted phase difference is , the calibrated phase difference is ; Calculate the length of the phasor block according to the calibrated phase difference, and the expression is: where the length of the phasor block is ; Output the corrected optical path difference, the adjusted phase difference and the length of the phasor block as corrected data.

[0009] Furthermore, a method for adaptive compensation of the phase shifter includes: Obtain the error source, establish the transfer matrix between the error source and the measurement result, and give the error transfer function, and the expression is: where the transpose of the matrix is , the transfer matrix is Q, the error transfer function is , the temperature error is , the air pressure error is , the wavelength error is , the phase error is ; Take the environmental parameters and the interference signal as state variables, and perform adaptive compensation on the measured length. The expression is: where the optimal estimated length at time t is , the Kalman gain at time t is , the current measured length at time t is , the optimal estimated length at time t-1 is ; Adjust the phase shifter voltage according to the real-time error, and the expression is: where the adjusted phase shifter voltage is , the initial voltage of the phase shifter is , the control parameter is , the target phase is , the phase at time t is .

[0010] Further, a method for correcting the length according to the uncertainty of the measurement data includes: Recording the laser wavelength stability and mechanical vibration, synchronizing the environmental data, temperature data, and interference fringe data using timestamp alignment technology, and establishing a quantitative relationship between each parameter and the measurement error through a calibration experiment; Obtaining environmental parameters from the environmental data and temperature data, introducing real-time environmental parameters to adjust the air refractive index, and the expression is: where the adjusted air refractive index is , the temperature is T, the air pressure is P, the humidity is H, the carbon dioxide concentration is C, and the empirical coefficients are respectively , , ; Converting the adjusted air refractive index into an optical path correction amount, and the expression is: where the optical path correction amount at time t is , the air refractive index at time t is , and the corrected optical path difference is ; Obtaining the fractional part of the multi-wavelength interference fringe, and solving the optimal interference fringe integer order by the least squares method, and the expression is: where the optimal interference fringe integer order is , the fractional part of the i-th interference fringe is , the wavelength of the i-th interference fringe is , and the length of the phase block is ; Obtaining the predicted length according to the adjusted phase shifter voltage, the adjusted air refractive index, the optical path correction amount, and the optimal interference fringe integer order, calculating the uncertainty according to the optimal estimated length and the predicted length, and continuously adjusting the phase shifter voltage, the air refractive index, the optical path correction amount, and the optimal interference fringe integer order until the uncertainty is less than 0.0012, and outputting the adjusted measured length as the measurement result.

[0011] In a second aspect, a high-resolution interferometer measurement system based on a phase shift block includes: A test preparation module: used to place the high-resolution interferometer and a preset phase block in an incubator, and introduce two frequency-stabilized lasers into the incubator through a single-mode optical fiber; the high-resolution interferometer includes an optical-mechanical system and a control system of the interferometer; the optical-mechanical system includes a beam expander system, a phase shifter, an adjustable mirror, a turntable system, and a fringe acquisition system; Interference fringe adjustment module: It is used to obtain interference fringe data by using the five-step phase-shifting method, adjust the interference fringe data according to the laser wavelength, and obtain adjusted data; the interference fringe data includes the interference fringe fraction and the interference fringe integer order; Temperature correction module: It is used to obtain the environmental data of the incubator containing the preset phasor block, and correct the adjusted data by eliminating the influence of changes based on the environmental data to obtain corrected data; the environmental data includes temperature, air pressure, humidity, and carbon dioxide content; Test output module: It is used to determine the length of the preset phasor block according to the interference fringe fraction and the interference fringe integer order at different wavelengths by the multi-wavelength fraction coincidence method, obtain the measurement data of the Kerr interferometer, perform adaptive compensation on the phase shifter, correct the length according to the uncertainty of the measurement data, and output the corrected length as the measurement result; including: Calculate the length of the phasor block: where the number of measured wavelengths is a, the preset block length for the number of wavelengths a is , in millimeters, the interference fringe integer order for the number of wavelengths a is , the interference fringe fraction for the number of wavelengths a is , the air refractive index for the number of wavelengths a is , the wavelength for the number of wavelengths a is .

[0012] The beneficial effects of the present invention are: The present invention is a measurement method and system for an ultra-high-resolution interferometer based on a phase-shifting block. Compared with the prior art, the present invention has the following technical effects: By steps of obtaining interference fringe data, obtaining adjusted data, obtaining corrected data, adaptive compensation, and uncertainty correction, the present invention can improve the measurement accuracy of the ultra-high-resolution interferometer, thereby improving the measurement precision of the ultra-high-resolution interferometer. Optimizing the measurement of the ultra-high-resolution interferometer can greatly save resources, improve work efficiency, can realize intelligent measurement of the ultra-high-resolution interferometer, perform adaptive compensation and uncertainty correction on the measurement of the ultra-high-resolution interferometer in real time, which is of great significance for the measurement of multiple ultra-high-resolution interferometers, and can adapt to different standards of ultra-high-resolution interferometer measurements and different ultra-high-resolution interferometer measurement requirements, and has a certain universality. Description of the Drawings

[0013] Figure 1 is the step flow chart of the measurement method of the ultra-high-resolution interferometer based on the phase-shifting block of the present invention. Detailed Embodiments

[0014] The present invention will be further described below through specific embodiments. The schematic embodiments and descriptions of the present invention are used to explain the present invention, but do not limit the present invention.

[0015] The method and system for measuring an ultra-high-resolution interferometer based on a phase-shifting block according to the present invention include the following steps: As Figure 1 shown, in this embodiment, it includes the following steps: Place the ultra-high-resolution interferometer and a preset phase-shifting block in an incubator, and introduce two frequency-stabilized lasers into the incubator through a single-mode optical fiber; the ultra-high-resolution interferometer includes an optical-mechanical system and a control system of the interferometer; the optical-mechanical system includes a beam expander system, a phase shifter, an adjustable mirror, a turntable system, and a fringe acquisition system; In actual evaluation, use a 633nm frequency-stabilized laser and a 543nm frequency-stabilized laser, turn on the device, stabilize the light source, expand the laser into parallel light using the beam expander system, and adjust the optical-mechanical components of the phase shifter and the adjustable mirror; Obtain interference fringe data using the five-step phase-shifting method, and adjust the interference fringe data according to the laser wavelength to obtain adjusted data; the interference fringe data includes the decimal part of the interference fringe and the integer order of the interference fringe; In actual evaluation, the decimal part of the interference fringe is 0.35 and the integer order is 158231 under the 633nm laser; the decimal part of the interference fringe is 0.42 and the integer order is 183457 under the 543nm laser; the adjusted data is that the decimal part of the interference fringe is 0.349 and the integer order is 158234 under the 633nm laser; the decimal part of the interference fringe is 0.423 and the integer order is 183456 under the 543nm laser; Obtain the environmental data of the incubator containing the preset phase-shifting block, and correct the adjusted data based on the environmental data by eliminating the influence of changes to obtain corrected data; the environmental data includes temperature, air pressure, humidity, and carbon dioxide content; In actual evaluation, the environmental data is a temperature of 20.2°C, an air pressure of 101.3 kPa, a humidity of 45%, and a carbon dioxide concentration of 400 ppm; the corrected data is that the actual wavelength of the 633nm laser becomes 632.999nm, and the actual wavelength of the 543nm laser becomes 542.998nm; Determine the length of the preset phase-shifting block according to the decimal part of the interference fringe and the integer order of the interference fringe at different wavelengths through the multi-wavelength decimal coincidence method, obtain the measurement data of the Kerr interferometer, perform adaptive compensation on the phase shifter, correct the length according to the uncertainty of the measurement data, and output the corrected length as the measurement result; including: Calculate the length of the phase-shifting block: where the number of measured wavelengths is a, and the preset block length for the number of wavelengths a is , in millimeters, the integer order of interference fringes for the number of wavelengths a is , the decimal part of the interference fringes for the number of wavelengths a is , the air refractive index for the number of wavelengths a is , the wavelength for the number of wavelengths a is ; In the actual evaluation, the length of the preset phasor block is 47.8 mm, the measured data are 50 mm in length, 26 mm in width, 10 mm in height, the uncertainty is 0.0149 μm, and the measurement result is 50.000032 mm.

[0016] In this embodiment, the method for obtaining interference fringe data by using the five-step phase-shifting method includes: Within an interference period of 2π, the phase shift interval for each time is π / 2, and the phase shifts are 0, π / 2, π, 3π / 2, 2π respectively, obtaining 5 interference fringe images. The five-step phase unwrapping algorithm is used to calculate the phase distribution map of the interference fringes and obtain the integer order of the interference fringes. The fringes of the block interference measurement include the block interference region, the flat crystal interference region, and the invalid region; Among them, the invalid region refers to the non-effective points, various noise points, and the block boundary region in the interference pattern; the block region and the flat crystal region within the interference fringes are discontinuous, and it is a discontinuous phase field; the phase unwrapping is performed on the interference fringes of the block surface and the flat crystal surface respectively, Taking the center point of the block as the starting point M0 for unwrapping, starting from M0, the phases of the 4 adjacent points in its up, down, left, and right directions are obtained to get the M1 phase; starting from M1, the phases of the 4 adjacent points that have not been unwrapped in its up, down, left, and right directions are respectively unwrapped to obtain the M2 phase, and so on, until all the points that have not been unwrapped within the block interference region are unwrapped, and the phase is output. The expression is: where the intensity distribution of the interference fringes in the c-th step is , the background light intensity is , the fringe contrast is , the phase to be measured is , the intensity distribution of the interference pattern of the first phase is , the intensity distribution of the interference pattern of the second phase is , the intensity distribution of the interference pattern of the third phase is , the intensity distribution of the interference pattern of the fourth phase is , the intensity distribution of the interference pattern of the fifth phase is ; Select the center point region of the block measurement surface and the corresponding flat crystal regions on both sides, and calculate the phase difference to obtain the interference decimal: The distance between the center of the interference fringes on the gauge surface and the center of the adjacent interference fringes on the flat crystal surface is h, the distance between the centers of two adjacent interference fringes on the flat crystal surface is f, and the interference decimal is .

[0017] In this embodiment, the method for adjusting the interference fringe data according to the laser wavelength includes: Calculating the optical path difference: Where the phase change of the interference fringe is , the optical path difference is , and the wavelength is ; Introducing two laser wavelengths and calculating the equivalent wavelength: Where the equivalent wavelength is , the wavelength of laser 1 is , and the wavelength of laser 2 is ; Adjusting the phase difference according to the equivalent wavelength, and the expression is: Where the adjusted phase difference is ; Outputting the adjusted phase difference as adjusted data.

[0018] In this embodiment, the method for obtaining the corrected data by correcting the adjusted data based on the environmental data by eliminating the variation influence includes: Obtaining the refractive index deviation caused by the environmental data and the temperature data change, calculating the air refractive index through the standard equation, and calculating the wavelength of light in vacuum: Where the wavelength of light in vacuum is , the wavelength of light in air is , the refractive index of the atmosphere is , and the refractive index deviation is ; Adjusting the actual wavelength of the laser, and the expression is: Where the adjusted actual wavelength of the laser is , and the refractive index of air under the conditions of temperature T, pressure P, humidity H, and carbon dioxide concentration C is ; Correcting the optical path difference according to the refractive index change, and the expression is: Where the corrected optical path difference is , and the speed of light is v; Correct the phase, and the expression is: where the adjusted phase difference is , and the corrected phase difference is ; Calculate the length of the phasor block according to the corrected phase difference, and the expression is: where the length of the phasor block is ; Output the corrected optical path difference, the adjusted phase difference, and the length of the phasor block as corrected data.

[0019] In this embodiment, the method for adaptively compensating the phase shifter includes: Obtain the error sources, establish the transfer matrix between the error sources and the measurement results, and give the error transfer function, and the expression is: where the transpose of the matrix is , the transfer matrix is Q, the error transfer function is , the temperature error is , the air pressure error is , the wavelength error is , and the phase error is ; Take the environmental parameters and the interference signal as state variables, and perform adaptive compensation on the measured length, and the expression is: where the optimal estimated length at time t is , the Kalman gain at time t is , the current measured length at time t is , and the optimal estimated length at time t-1 is ; Adjust the phase shifter voltage according to the real-time error, and the expression is: where the adjusted phase shifter voltage is , the initial voltage of the phase shifter is , the control parameter is , the target phase is , and the phase at time t is .

[0020] In this embodiment, the method for correcting the length according to the uncertainty of the measurement data includes: Record the laser wavelength stability and mechanical vibration, synchronize the environmental data, temperature data, and interference fringe data using timestamp alignment technology, and establish a quantitative relationship between each parameter and the measurement error through a calibration experiment; Obtain environmental parameters from the environmental data and temperature data, introduce real-time environmental parameters to adjust the air refractive index, and the expression is: Among them, the adjusted air refractive index is , the temperature is T, the air pressure is P, the humidity is H, the carbon dioxide concentration is C, and the empirical coefficients are respectively 、 、 ; Convert the adjusted air refractive index into an optical path correction amount, and the expression is: Among them, the optical path correction amount at time t is , the air refractive index at time t is , and the corrected optical path difference is ; Obtain the fractional part of the multi-wavelength interference fringes, and solve the optimal interference fringe integer order through the least squares method. The expression is: Among them, the optimal interference fringe integer order is , the fractional part of the i-th interference fringe is , the wavelength of the i-th interference fringe is , and the length of the phase block is ; Obtain the predicted length based on the adjusted phase shifter voltage, adjusted air refractive index, optical path correction amount, and optimal interference fringe integer order. Calculate the uncertainty based on the optimal estimated length and the predicted length, and continuously adjust the phase shifter voltage, air refractive index, optical path correction amount, and optimal interference fringe integer order until the uncertainty is less than 0.0012, and output the adjusted measured length as the measurement result.

[0021] In the second aspect, a high-resolution interferometer measurement system based on a phase shift block includes: A test preparation module: used to place the high-resolution interferometer and a preset phase block in an incubator, and introduce two frequency-stabilized lasers into the incubator through a single-mode optical fiber; the high-resolution interferometer includes the optical-mechanical system and the control system of the interferometer; the optical-mechanical system includes a beam expansion system, a phase shifter, an adjustable mirror, a turntable system, and a fringe acquisition system; Interference fringe adjustment module: It is used to obtain interference fringe data by using the five-step phase-shifting method, adjust the interference fringe data according to the laser wavelength, and obtain adjusted data; the interference fringe data includes the interference fringe fraction and the interference fringe integer order; Temperature correction module: It is used to obtain the environmental data of the incubator containing the preset phasor block, and correct the adjusted data by removing the influence of changes based on the environmental data to obtain corrected data; the environmental data includes temperature, air pressure, humidity, and carbon dioxide content; Test output module: It is used to determine the length of the preset phasor block according to the interference fringe fraction and the interference fringe integer order at different wavelengths by using the multi-wavelength fraction coincidence method, obtain the measurement data of the Kerr interferometer, perform adaptive compensation on the phase shifter, correct the length according to the uncertainty of the measurement data, and output the corrected length as the measurement result; including: Calculate the length of the phasor block: where the number of measured wavelengths is a, the length of the preset block for the number of wavelengths a is , in millimeters, the interference fringe integer order for the number of wavelengths a is , the interference fringe fraction for the number of wavelengths a is , the air refractive index for the number of wavelengths a is , the wavelength for the number of wavelengths a is .

[0022] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A measurement method of an ultra-high resolution interferometer based on a phase-shifting block, characterized in that It includes the following steps: Place the ultra-high resolution interferometer and the preset phasor block in an incubator, and introduce two frequency-stabilized lasers into the incubator through a single-mode optical fiber; the ultra-high resolution interferometer includes the optical-mechanical system and the control system of the interferometer; the optical-mechanical system includes a beam expander system, a phase shifter, an adjustable mirror, a turntable system, and a fringe acquisition system; Obtain interference fringe data using the five-step phase shift method, adjust the interference fringe data according to the laser wavelength to obtain adjusted data; the interference fringe data includes the interference fringe fraction and the interference fringe integer order; Obtain the environmental data of the incubator containing the preset phasor block, and correct the adjusted data by eliminating the influence of changes based on the environmental data to obtain corrected data; the environmental data includes temperature, air pressure, humidity, and carbon dioxide content; use a thermocouple to measure the temperature of the air and the preset phasor block in the incubator; Determine the length of the preset phasor block according to the interference fringe fraction and the interference fringe integer order at different wavelengths by the multi-wavelength decimal recombination method, obtain the measurement data of the Kerr interferometer, perform adaptive compensation on the phase shifter, correct the length according to the uncertainty of the measurement data, and output the corrected length as the measurement result; including: Calculate the length of the phasor block: where the number of measured wavelengths is a, and the preset block length for the number of wavelengths a is , in millimeters, the integer order of interference fringes for the number of wavelengths a is , the decimal part of the interference fringes for the number of wavelengths a is , the air refractive index for the number of wavelengths a is , the wavelength for the number of wavelengths a is .

2. The method for measuring by using a high-resolution interferometer based on a phase-shifting block according to claim 1, wherein The method for obtaining interference fringe data using the five-step phase shift method includes: Within an interference period of 2π, the phase shift interval is π / 2 each time, and the phase shifts are 0, π / 2, π, 3π / 2, 2π respectively, to obtain 5 interference fringe images. Use the five-step phase unwrapping algorithm to calculate the phase distribution map of the interference fringes and obtain the interference fringe integer order. The fringes of the block interference measurement include the block interference region, the flat crystal interference region, and the invalid region; Among them, the invalid region refers to the non-effective points, various noise points, and the block boundary region in the interference pattern; the block region and the flat crystal region in the interference fringes are discontinuous, and it is a discontinuous phase field; perform phase unwrapping on the interference fringes of the block surface and the flat crystal surface respectively, Take the center point of the block as the starting point M0 for unwrapping. Starting from M0, unwrap the phases of the 4 adjacent points in the up, down, left, and right directions to obtain the M1 phase; starting from M1, unwrap the phases of the 4 adjacent points that have not been unwrapped in the up, down, left, and right directions respectively to obtain the M2 phase, and so on, until all the points that have not been unwrapped in the block interference region are unwrapped, and output the phase. The expression is: Among them, the interference fringe intensity distribution in the c-th step is , the background light intensity is , the fringe contrast is , the phase to be measured is , the interference pattern intensity distribution of the first phase is , the interference pattern intensity distribution of the second phase is , the interference pattern intensity distribution of the third phase is , the interference pattern intensity distribution of the fourth phase is , the interference pattern intensity distribution of the fifth phase is ; Select the center point region of the block measurement surface and the corresponding flat crystal regions on both sides, and calculate the phase difference to obtain the interference fraction: where the distance between the center of the interference fringes on the gauge block surface and the center of the adjacent interference fringes on the flat crystal surface is h, the distance between the centers of two adjacent interference fringes on the flat crystal surface is f, and the interference fraction is .

3. The method for measuring an ultra-high resolution interferometer based on a phase shift block according to claim 1, characterized in that, The method for adjusting the interference fringe data according to the laser wavelength includes: Calculate the optical path difference: where the phase change of the interference fringes is , the optical path difference is , and the wavelength is ; Introduce two laser wavelengths and calculate the equivalent wavelength: where the equivalent wavelength is , the wavelength of Laser 1 is , and the wavelength of Laser 2 is ; Adjust the phase difference according to the equivalent wavelength. The expression is: wherein the adjusted phase difference is ; and output the adjusted phase difference as adjusted data.

4. The method for measuring an ultra-high resolution interferometer based on a phase-shifting block according to claim 1, characterized in that The method for correcting the adjusted data by eliminating the influence of changes based on the environmental data to obtain corrected data includes: Obtain the refractive index deviation caused by the change in environmental data and temperature data, calculate the air refractive index through the standard equation, and calculate the wavelength of light in a vacuum: where the wavelength of light in vacuum is , the wavelength of light in air is , the refractive index of the atmosphere is 1, and the refractive index deviation is ; Adjust the actual wavelength of the laser. The expression is: where the actual wavelength of the adjusted laser is , and the refractive index of air under the conditions of temperature T, air pressure P, humidity H, and carbon dioxide concentration C is ; Correct the optical path difference according to the refractive index change. The expression is: where the corrected optical path difference is , the speed of light is v; Correct the phase. The expression is: where the adjusted phase difference is , and the corrected phase difference is ; Calculate the length of the phasor block according to the corrected phase difference. The expression is: wherein the length of the phasor block is ; output the corrected optical path difference, the adjusted phase difference, and the length of the phasor block as corrected data.

5. The method for measuring an ultra-high resolution interferometer based on a phase shift block according to claim 1, wherein A method for adaptively compensating the phase shifter includes: Obtaining an error source, establishing a transfer matrix between the error source and the measurement result, and giving an error transfer function, the expression of which is: where the transpose of the matrix is , the transfer matrix is Q, and the error transfer function is , the temperature error is , the air pressure error is , the wavelength error is , the phase error is ; Taking the environmental parameters and the interference signal as state variables to perform adaptive compensation on the measured length, the expression of which is: where the optimal estimated length at time t is , the Kalman gain at time t is , the current measured length at time t is , and the optimal estimated length at time t-1 is ; Adjusting the voltage of the phase shifter according to the real-time error, the expression of which is: where the adjusted voltage of the phase shifter is , the initial voltage of the phase shifter is , the control parameter is , the target phase is , and the phase at time t is .

6. The method for measuring based on a phase-shifting block high-resolution interferometer according to claim 1, wherein A method for correcting the length according to the uncertainty of the measured data includes: Recording the laser wavelength stability and mechanical vibration, synchronizing the environmental data, temperature data and interference fringe data by using the timestamp alignment technology, and establishing a quantitative relationship between each parameter and the measurement error through a calibration experiment; Obtaining the environmental parameters through the environmental data and the temperature data, and introducing the real-time environmental parameters to adjust the air refractive index, the expression of which is: where the adjusted refractive index of air is , the temperature is T, the air pressure is P, the humidity is H, the carbon dioxide concentration is C, and the empirical coefficients are respectively , , ; Converting the adjusted air refractive index into an optical path correction amount, the expression of which is: where the optical path correction at time t is , the air refractive index at time t is , and the corrected optical path difference is ; Obtaining the fractional part of the multi-wavelength interference fringes, and solving the optimal interference fringe integer order by the least square method, the expression of which is: Among them, the optimal integer order of interference fringes is , the fractional part of the i-th interference fringe is , the wavelength of the i-th interference fringe is , and the length of the phasor block is ; Obtaining a predicted length according to the adjusted phase shifter voltage, the adjusted air refractive index, the optical path correction amount and the optimal interference fringe integer order, calculating the uncertainty according to the optimal estimated length and the predicted length, continuously adjusting the phase shifter voltage, the air refractive index, the optical path correction amount and the optimal interference fringe integer order until the uncertainty is less than 0.0012, and outputting the adjusted measured length as the measurement result.

7. A high-resolution interferometer measurement system based on a phase-shifting block for performing the method according to any one of claims 1-6, characterized in that It includes: A test preparation module: used to place a super-high-resolution interferometer and a preset phasor block in an incubator, and introduce two kinds of frequency-stabilized lasers into the incubator through a single-mode optical fiber; the super-high-resolution interferometer includes an optical-mechanical system and a control system of the interferometer; the optical-mechanical system includes a beam expander system, a phase shifter, an adjustable mirror, a turntable system and a fringe acquisition system; An interference fringe adjustment module: used to obtain interference fringe data by using the five-step phase shift method, and adjust the interference fringe data according to the laser wavelength to obtain adjusted data; the interference fringe data includes the interference fringe fraction and the interference fringe integer order; A temperature correction module: used to obtain the environmental data of the incubator containing the preset phasor block, and correct the adjusted data based on the environmental data by eliminating the influence of changes to obtain corrected data; the environmental data includes temperature, air pressure, humidity and carbon dioxide content; A test output module: used to determine the length of the preset phasor block according to the interference fringe fraction and the interference fringe integer order at different wavelengths by the multi-wavelength fractional coincidence method, obtain the measurement data of the Kerr interferometer, perform adaptive compensation on the phase shifter, correct the length according to the uncertainty of the measurement data, and output the corrected length as the measurement result; it includes: Calculating the length of the phasor block: where the number of measured wavelengths is a, and the preset block length for the number of wavelengths a is , in millimeters, the integer order of the interference fringes for the number of wavelengths a is , the decimal part of the interference fringes for the number of wavelengths a is , the air refractive index for the number of wavelengths a is , the wavelength for the number of wavelengths a is .

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