WIDE-ANGLE HIGH-POWER INFRARED LENS Russian patent published in 2019 - IPC G02B13/14 G02B9/34 

FIELD: physics.

SUBSTANCE: lens can be used in thermal imagers sensitive in spectral range from 8 to 12 mcm. Lens contains four components, of which the first and second along the beam are positive menisci, facing the concave surfaces to the image plane, and the third is a negative meniscus facing a concave surface to the image plane. Fourth is a positive meniscus, facing a concave surface toward the plane of the images, or a convex-flat lens. First and fourth components are made of germanium, the second is made of chalcogenide glass IRG-26, the third is made of chalcogenide glass IRG-25. Second surfaces of the first and second components along the beam are made aspherical, the conical constants of which lie within: C2=4.2÷15.0; C4=2.6÷4.8, where: C2, C4 – conic constants of aspherical surfaces, respectively, of the first and second components. Following ratios are met: 3.57f'_Σ<f'₁<5f'_Σ, 0.6f'_Σ<f'₂<0.64f'_Σ, -0.52f'_Σ<f'₃<-0.45f'_Σ, 0.75f'_Σ<f'₄<0.81f'_Σ, where: f'₁, f'₂, f'₃, f'₄ – focal lengths of the first, second, third, and fourth components, respectively; f'_Σ – focal length of the lens.

EFFECT: increasing the field of view, providing high quality images throughout the field of view and increasing the relative aperture.

1 cl, 3 dwg, 1 tbl