Study On The Center Thickness Of Coated Lens Based On Dispersion Spectrum Analysis

With the rapid development of modern science and technology,optical coated lenses have become more and more popular in military,medical and civilian applications.As an important part of most high precision instruments,the quality of coated lenses is extremely important,and whether the center thickness meets the requirement is an important aspect that determines the quality of coated lens.We need to measure the center thickness of the coated lens through a certain method to determine whether it meets the requirements.Therefore,the research on the detection of the coated lens center thickness has important significance for improving the processing precision and the performance of the related equipment.In the environment where non-contact detection technology has gradually become mainstream technology,this paper has conducted in-depth research on the non-contact detection technology of coated lens center thickness based on dispersive spectrum analysis.The main research contents of the paper are as follows:Firstly,it introduces the research background of non-contact detection and the research status of transparent material thickness measurement and confocal detection technology at home and abroad.The overall structure and measurement scheme of the coated lens center thickness detection device are given,and the appropriate type of light source,optical fiber and spectrometer are selected according to the characteristics of the coated lens.The confocal optical system suitable for the detection of coated lens center thickness is created by using the optical software.Firstly,the initial parameters such as numerical aperture,axial chromatic aberration range and working wavelength of the confocal system are determined,and the entire confocal optical system is optimized by establishing multiple configuration relationships and adding appropriate operands.The optimization is mainly focused on spherical aberration and axial chromatic aberration in geometric aberrations,making the confocal system's design wavelength focus well on each focal plane,while producing a large axial color difference.After that,the various factors affecting the thickness measurement of the coated lens center are analyzed by combining dispersion spectrum,and then the mathematical model of the coated lens center thickness is obtained by using mathematical software to fit the relationship between them.By programming and using the least squares method to solve the optimal solution of each parameter in the model,the model formula of the coated lens center thickness is finally established.At last,the center thickness of coated lenses of different specifications was measured several times,the obtained measurement data shows that the detection device meets the accuracy requirements for the center thickness measurement of the coated lens.The main sources of system errors were analyzed in detail,and corresponding treatment methods were proposed according to different sources.