OPTICAL SYSTEM OF IR RANGE OF SPECTRUM

FIELD: optics. SUBSTANCE: optical system includes main concave mirror, aperture diaphragm and lens compensator installed in converging bundle of rays and photodetector. Zone of ray propagation from diaphragm to photodetector is limited by light-proof tube. Light- proof tube and aperture diaphragm are cooled and diameter D of optical surface of main mirror corresponds to condition D>fd/(f-L)+2Lsinomega, where f is focal distance of main mirror; d is diameter of aperture diaphragm; L is distance from main mirror to aperture diaphragm; omega is half of round angle of view. Lens compensator can be installed in light-proof tube, between aperture diaphragm and photodetector. Light-proof tube can be placed inside central hole of scanning inclined mirror mounted across input of system. EFFECT: reduced effect of thermal background caused by radiation of elements of optical system, high temperature resolution with preservation of simplicity, small dimensions and negligible detuning. 2 cl, 3 dwg, 3 tbl