Research On Calibration Method Of Surface Measurement Based On White Light Interference

The progress of industry and technology have made all kinds of components increasingly miniaturized and complicated.At the same time,the requirements for component surface quality are more stringent.Therefore,how to carry out accurate surface scanning measurement on the component surface has become a research hotspot.The existing measurement technology can be divided into contact type and non-contact type.Because the contact type may cause surface damage in measurement,while the non-contact type avoids direct contact with the surface,the non-contact type has become the development trend of surface scanning measurement technology.In the non-contact measurement technology,optical fiber white light interference technology has been widely used because of its advantages of large dynamic measurement range,strong anti-interference ability,high resolution and absolute measurement.In this dissertation,the surface scanning measurement of bonded plate strip crystal is carried out based on optical fiber white light interference.The errors existing in device,point measurement and surface measurement in the test system are studied,and the calibration analysis is carried out.The main work are as follows:Firstly,the errors in optical fiber white light interferometry are calibrated and analyzed.The influence of airflow disturbance and temperature change on the test results are verified by experiments.By using the time-domain distribution results of pen red light source,optical power meter,measurement system and "three-point alignment",the problem of point beam alignment of optical fiber probe in the test system is solved.Secondly,the errors in the process of point measurement are calibrated and analyzed.The dispersion coefficient at each spot position is calculated according to the phase spectrum at different positions of the side bonding surface of the crystal swept by the light spot of the optical fiber probe.A reflective measurement method is used to measure the beam intensity distribution.By comparing the experimental and simulation results,it is found that the intensity distribution of the optical fiber probe is an ideal beam with Gaussian distribution.The Gaussian fitting and the one-dimensional interpolation algorithms are combined to improve the consistency of data in the process of repeated measurement and the accuracy of interference signal peak extraction.Then,the calibration analysis of the errors in the process of face scanning measurement is carried out.The hysterisis error in each direction of the displacement platform are tested experimentally,and the hysterisis errors in the upper and lower directions are less than those in the left and right directions,and the hysterisis errors are independent of the stepping amount of the displacement platform.The path planning principle of surface scanning measurement is designed.Finally,according to the planned path,the surface scanning measurement is carried out on the lithography surface and the bonded strip crystal.The simulation and experimental result have good consistency.The surface interpolation algorithm is combined to improve the efficiency of surface scanning measurement.