Athermal thermal imaging optical system

The invention relates to an athermalization thermal imaging optical system, belongs to the technical field of athermalization imaging, and solves the problems that an existing optical system is limited by illumination conditions and temperature, cannot achieve clear imaging and is complex in structure. The athermalization thermal imaging optical system sequentially comprises a first lens, a second lens, a third lens, a fourth lens and an infrared focal plane detector from an object space to an image space along a light incidence direction, the first lens is a concave-convex negative focal power lens; the second lens is a biconvex lens with positive focal power; the third lens is a meniscus lens with negative focal power; and the fourth lens is a meniscus lens with positive focal power. The optical system can achieve all-weather clear imaging without being limited by illumination conditions, meanwhile, the optical system can adapt to the wide-temperature-range environment, and the overall structure is miniatur