HIGH-APERTURE WIDE-ANGLE OBJECTIVE LENS FOR INFRARED SPECTRUM Russian patent published in 2011 - IPC G02B13/14 G02B9/60 

FIELD: physics.

SUBSTANCE: objective lens comprises five meniscus lenses with spherical surfaces and an aperture diaphragm between the fifth meniscus lens and the focal plane. The first and third meniscus lenses face the object space with their convex surface. The second, fourth and fifth meniscus lenses face the object space with their concave surface. The first and fourth meniscus lenses are made from germanium, while the second, third and fifth are made from monocrystalline silicon. The second meniscus lens has the longest diameter. Optical power values φ₁-φ₅ of the first-fifth meniscus lenses satisfy the following conditions: (0.62<φ₁<0.66), (0.16<φ₂<0.20), (0.18<φ₃<0.22), (0.35<φ₄<0.39), (0.30<φ₅<0.34). The distance between the meniscus lenses is equal to D·f, where D is a coefficient, f is the focal distance of the objective lens. The coefficients satisfy the following conditions: (5.0<D_1-2<6.0), (0.15<D_2-3<0.25), (0.85<D_3-4<0.95), (1.3<D_5-AD<1.5). The conditions (3.5γ<⌀₂<4.0γ) and ⌀₁<⌀₂ are satisfied, where ⌀₁ and ⌀₂ are the diameter of the input and output meniscus lenses, γ is the dimension of the diagonal of the photodetector matrix. The position of the aperture diaphragm coincides with the exit pupil of the objective lens.

EFFECT: ensuring operation from 2,0 to 6,0 mcm, high image quality and uniformity on the field of vision with low size and weight.

2 cl, 1 dwg