Research On Key Technologies Of Large-scale Two-dimensional Coordinate Metrology Based On Laser Interferometer

Large-scale two-dimensional grid physical standards(two-dimensional optical standards,masks,two-dimensional grating measurement systems,etc.)are indispensable in high-end equipment manufacturing and precision measurement.The method of combining laser interferometric length measurement and image measurement are mainly used to measure commonly used small and medium twodimensional grid physical standards.However,the current measurement range is limited and does not meet the comprehensive evaluation of the large-scale twodimensional grid physical standards.At present,most large-scale two-dimensional grid objects are measured by splicing measurement or large-scale optical precision instrument measurement,but the measurement accuracy is limited.This paper designs a large-scale reference grid measurement method based on the principle of multi-axis laser interference,and builds a large-scale laser grid measurement machine.The research is carried out from several aspects such as the overall structure and hardware composition of the device,the construction of the measurement system,the establishment and correction of the measurement error model of the device,and the measurement verification experiment.The main research work of this paper is as follows:(1)This article firstly analyzes the main requirements and characteristics of the large-scale two-dimensional grid physical standard calibration,and proposes an overall implementation plan for a large-scale reference grid measurement standard device.At the same time,the article analyzes the key technologies to realize the calibration function and improve the measurement accuracy according to the overall realization plan.(2)A large-scale reference grid measurement standard device based on a multiaxis laser interferometer has been built.The measurement structure,movement module composition and construction process of the standard device are described;a measurement system based on multi-axis laser interference length measurement is built;based on the Edlén formula,an air refractive index correction system that corrected the wavelength in real time has been built;the synchronous dynamic measurement control system is adopted,which can realize the dynamic calibration measurement of the twodimensional grid physical standard,and improve the measurement efficiency and measurement accuracy;this paper develops two-dimensional motion control software and multi-axis laser synchronous measurement software based on C# and integrates each module effectively.(3)The main geometric error sources of the experimental device are analyzed;an error model containing geometric error terms is established;and this paper establishes a multi-axis laser interference length measurement model.When the measured twodimensional grid physical standard is a two-dimensional grating measurement system,the influence of the installation error on the display value of the two-dimensional grating is analyzed.A coordinate transformation model is established for the installation error;a method for correcting the measurement results is proposed.(4)The large-scale reference grid measurement standard device has been verified through experiments.A standard laser interferometer was used to conduct a comparison experiment on the laser interferometric length measurement system;the dynamic measurement experiment was carried out with a photoelectric microscope to achieve dynamic high-precision measurement;a standard device was used to measure the twoposition grating system,and an error correction model was used to correct the result.After using the model to correct the geometric error,the X and Y measurement errors of the device are reduced by 96.8% and 98.8% respectively.