ULTRA-WIDE-ANGLE HIGH-APERTURE RETROFOCUS ATHERMAL INFRARED LENS Russian patent published in 2025 - IPC G02B9/34 G02B13/14 

FIELD: physics.

SUBSTANCE: invention relates to ultra-wide-angle high-aperture retrofocus athermal infrared lenses. Lens has four optical components. First component is a negative aspherical meniscus and faces the image plane by the concave aspherical surface, second has positive optical power and is made in the form of a biconvex lens and a positive meniscus whose convex surface faces the biconvex lens, the third is a single negative aspherical biconcave lens, the fourth is a single positive aspherical biconvex lens. Number of grades of materials does not exceed three, and the thermooptical constants of the materials are negative, wherein the following ratios are satisfied: φ₁:φ₂:φ₃:φ₄=-(0.8÷0.9):(0.5÷0.6):-(0.1÷0.2):(0.5÷0.6), where φ₁, φ₂, φ₃, φ₄ are optical forces of the first, second, third, fourth components, respectively; d₁ < 1.4, d₂ < 0.8, where d₁, d₂ are distances between the first and second, second and third components, respectively.

EFFECT: increase of angular field above 83°, preservation of diffraction quality.

3 cl, 2 dwg, 3 tbl