INTERFERENCE COATING Russian patent published in 1998 - IPC

FIELD: optical instruments. SUBSTANCE: coating consists of intermittent layers of two types, one of which has low refraction index levels and is made from MgF₂. Second type of layers has high refraction index and is made from material which is transparent for infrared light and has refraction index of at least 2.2 compressing pressing tensions in layer. Insertion of SiO₂ is introduced in center of MgF₂ layers. Depth of this insertion is within range of 0.2-0.5 of optical depth of MgF₂ layer by corresponding decrease in its depth. Layers with high refraction index may be made from zinc sulfide or selenide, or antimony sulfide, or arsenic sulfide or selenide. Cover layer of material with high refraction index may be covered by protection half-wave layer with low refraction index consisting of quarter-wave MgF₂ layer with SiO₂ insertion and quarter-wave SiO₂ layer. EFFECT: increased field of application for long waves, improved performance characteristics. 3 cl, 1 dwg