WIDE ANGLE ATHERMALIZED INFRARED LENS WITH LARGE BACK Russian patent published in 2021 - IPC G02B13/14 G02B13/18 G02B9/34 

FIELD: optics.

SUBSTANCE: lens can be used in thermal imagers with microbolometric arrays that do not require cooling to cryogenic temperatures, sensitive in the spectral range of 8-12 microns. The lens contains four components. The first is a negative meniscus made of germanium, the second is a positive meniscus made of IKS-25 oxygen-free glass, the third is a negative meniscus made of zinc selenide, and the fourth is a biconvex lens made of IKS-25 glass. The first component is installed with a concave surface to the space of objects, and the second and third are facing with concave surfaces to the image plane. The first surface of the first component is made aspherical with a conical constant in the range from 0.22 to 0.26. The following ratios are fulfilled: ϕ₁:ϕ₂:ϕ₃:ϕ₄=-(0.014÷0.073):(0.69÷0.82):-(0.97÷1.15):(1.2÷1.25), where ϕ₁, ϕ₂, ϕ₃, ϕ₄ are the relative optical powers of the first, second, third and fourth components, respectively.

EFFECT: increase in the field of view, an increase in the rear section and an increase in the manufacturability of the lens while maintaining the diffraction quality of the image throughout the entire field of view.

1 cl, 3 dwg, 3 tbl