CATADIOPTRIC LENS Russian patent published in 2013 - IPC G02B17/08 

FIELD: physics.

SUBSTANCE: lens has four components arranged on the beam path: a main mirror, a secondary internal reflection mirror placed near the intermediate image plane of the third component and an inversion system consisting of two lenses, one of which is a negative meniscus whose concave side faces a second biconvex lens. All refracting and reflecting surfaces are spherical. The third component is in form of two closely arranged converging and diverging lenses. The refraction indices and basic average variance coefficients of materials of the lenses located on the beam path can satisfy the relationships: 1.61<n₁<1.67; 1.61<n₂<1.67; 1.78<n₃<1.91; 1.57<n₄<1.65; 1.70<n₅<1.81; 54<ν₁<61; 55<ν₂<64; 22<ν₃<41; 33<ν₄<55; 40<ν₅<54. The converging lens of the third component can be biconvex or in form of a meniscus whose concave side faces the intermediate image plane, and the diverging lens can be in form of a meniscus whose concave side faces the intermediate image plane.

EFFECT: wider operating spectral range, high aperture ratio and larger angular field while maintaining high image quality.

4 cl, 3 dwg