Surface Quality Detection Technology Of Optical Components Based On Regional Scattering

With the rapid development of the modern optical industry,optical components have been widely used in inertial confinement nuclear fusion,aerospace,micro-optics and large-scale integrated circuits.However,during the manufacturing and processing of optical components,the problems of their own materials and processing methods will cause the surface roughness to be too large,and cause defects such as pitting and scratches.Surface roughness will affect the mechanical,physical and operational performance of the system,and will degrade the beam quality inside the system,increase system noise,and cause laser-induced damage.Therefore,rapid and accurate detection of surface quality of optical components is studied in this paper.The main research contents include:1)To solve the problem that the traditional Angular Resolution Scattering method needs to detect the scattering intensity in the whole hemispherical space,cause the detection speed is slow.A surface quality detection method based on regional scattering is proposed.By studying the scattering theory of random rough surfaces and defects of optical components,the Rayleigh scattering model of rough surface,the Rayleigh scattering model of surface defects and the Fraunhofer diffraction model are established,and the regional scattering distribution model is further established.By simulating and analyzing the Bidirectional Reflection Distribution Function variation law of random rough surface and surface defects under different variables,it is determined that the scattered light intensity is collected in a fixed area,which can realize the rapid detection of the surface roughness value and defect size of optical components.2)To solve the problem that the low dynamic range of a single scattering image affects the detection accuracy of the surface quality of optical components,a large dynamic range scattering signal acquisition method based on the improved wavelet transform fusion method is proposed.Firstly,the weighted average method,Laplacian pyramid transform method and wavelet transform method are used to fuse the multi-exposure scattering images.Then,by combining the traditional wavelet transform method with the scattering theory of optical components,an improved wavelet transform method suitable for scattering image fusion is proposed.Finally,the results of several fusion methods are compared and analyzed,and it is found that the dynamic range of the scattered signal fused by the improved wavelet transform method is increased by 3 orders of magnitude compared with the unfused scattered signal,and the surface quality of the optical components can be accurately achieved.3)An experimental device was built based on the principle of Angle Resolution Scattering principle to conduct experimental research on the surface quality detection of optical components.Firstly,the collected optical element surface scattering images are fused;Then,Angular Resolution Scattering method and scattering field fitting method are used to calculate the roughness value and defect size of the element surface.Finally,The roughness value is compared with the detection results of the horos scatterometer,and the defect size is compared with the detection results of the white light interferometer,and the detection results are basically consistent.Therefore,it is verified that the method in this paper can realize the rapid and accurate detection of the surface roughness and surface defects of optical components.