TELESCOPIC SIGHT WITH DISCRETE CHANGE OF MAGNIFICATION Russian patent published in 2015 - IPC F41G1/14 

FIELD: physics.

SUBSTANCE: telescopic sight with discrete change of magnification consists of an objective lens, a grid which is movable perpendicular to the optical axis to change the direction of the axis of sight of the telescopic sight, an erecting system and an eyepiece, wherein the erecting system consists of four components, the first and third of which are moved from the beam path when changing magnification, wherein φ₁=(1.4-1.8)φ₂; φ₃=-(2-2.6)φ₂; φ₄=(0.6-0.9)φ₂; ƒ'_l=(0.6-1)s'_p'=(0.7-0.9)ℓ_er=(0.2-0.4)L; D:ƒ'_l≥1:1.6; Δn/ΔT=(-10-9)·10^-6deg^-1, where φ₁, φ₂, φ₃, φ₄ represent the optical power of the first, second, third and fourth components of the erecting system; ƒ'_l is the focal distance of the objective lens; D:ƒ'_l is the relative aperture of the objective lens; s'_p' is the distance of the exit pupil of the telescopic sight from the last surface of the eyepiece; ℓ_er is the length of the erecting system (distance along the optical axis between the object and image planes in the erecting system); L is the length of the optical system of the telescopic sight (distance along the optical axis between the first refracting surface of the objective lens on the beam path and the last refracting surface of the eyepiece); Δn/ΔT is the value of temperature change of the refraction index of the lens materials of the optical system.

EFFECT: realising discrete change of magnification with a differential of not less than 4 times, shorter length of the optical system, providing the same distance of the exit pupil for each magnification, high twilight factor, providing thermal stability of the optical system while maintaining internal alignment and high image quality within the entire field for each magnification.

9 cl, 3 tbl, 2 dwg