The Research Of Ellipsoidal Optical Element Coating Uniformity

Film thickness uniformity is one of the important indicators of performance appraisal film,for the shape of small and relatively flat optical element,the uniformity of film thickness will be generally get good control.For the large curvature of the surface of the spherical substrate,especially the inner surface,due to the Angle of incident particle change is quite big,become almost zero grazing incidence from normal incidence,leads to the change of sedimentary particles get energy greatly,resulting in serious problem of film thickness uniformity.This thesis is to explore the specific diameter and depth ratio of 4:1 ellipsoidal optical element in the uniformity of surface coating.Based on the factors that affect the film thickness distribution of ellipsoidal mirror adjustment,to adjust and improve its film thickness uniformity.In view of the ellipsoidal optical element film uniformity are analyzed in theory research.Through the mathematical model was established,the inner surface of the basal theory of film thickness formula expresses the inner surface of the film thickness distribution.Calculates the support structure's rotation,vacuum chamber pressure and ion source assisted deposition on the influence of film thickness is analyzed.The research work in this kind of large caliber film plating process has a certain guiding significance,to improve the uniformity of surface film layer provides theory basis.