Scattering Method Detection For Optical Element Surface Defects Technology Research

Automatic detection technology to the optical components surface defect is being taken seriously by more and more people. In this paper, based on the defects scattering characteristics, designed a detection system for spherical optical element surface defect detecting, completed the experimental platform structures, analysis of the experimental results. This technology can be intuitive, fast detection element surface defects and suitable for the use of industrial field environments, which has a certain application value in industrial test field.In this paper, we studied on scattering imaging aimed at the pits and scratch defects on the surface of spherical optical element, the mainly work carried out as follows:(1)Analyzed classification method and evaluation standard about defects, determined the contents of the Defects detection. Based on the theory of light scattering, studied the optical element surface scattering source and treatment method, set up defects light scattering model, put forward the theory of microscopic imaging method to detect defects.(2)This paper had designed a system model which was used to detect optical element’s surface defects. This system combines lighting system, microscopic imaging system and the scanning system together. Meanwhile, the system components was determined, each components of the parameters was calculated, experimental components were selected, and the main factors which affect the scattering imaging quality of defects are analyzed, and finally finished the experiment platform.(3)The experiment get scattering image about pits and scratches,this image was preprocessed by filtering noise, correcting uneven illumination, detecting edge and binarization processing, so that noise interference in defect scattering image can be reduced and utilization of scattering image is also improved. It can lay a good foundation for the precise calculation of defect disease characteristic in next step.(4)It demarcated the actual width of the pits and scratches by using high-precision microscope. According to calculating the eigenvalues,it picks up the width information about the scattering image of defects, obtains the function relationship between the width of the scattering image and defects through data comparison. The function realizes quantitative detection of defects.(5)By studied the classification of pits and scratches, calculated the feature amounts of shape factor, the ratio of the minor axis and the major axis and rectangle degree.Through statistical analysis, it determined the threshold value to distinguish pits or scratches, which provides a reference for distinction of defect types.The research is the trial and exploration on detecting spherical optical element surface defects using by scattering method microscopic imaging technique, it completes the detection of defects from theory to experiment, the result prove that using the scattering method to detect the defects of spherical optical element surface with certain feasibility.