Duplex band/duplex FOV infrared ray telescope

摘要

PURPOSE: To correct residual axial chromatic aberrations in both bands of a middle IR band and long IR band by selecting the lenses of respective groups from zinc sulfide, germanium and non-oxidized chalcogen glass and using negative lenses of germanium for objective lens groups. CONSTITUTION: The telescope operating at both bands of the middle IR band having radiations of wavelengths of 3.8 and 5 micrometers and the long IR band having radiations of wavelengths of 8 and 11.5 micrometers has the objective lens group A and eyepiece group B on the optical axis O. The lenses of the respective groups are any one selected from the zinc sulfide, germanium and non-oxidized chalcogen glass. The objective lens group A consists of the lenses A1, A2 constituting the front lens pair and the lenses A3, A4 constituting the rear lens pair. The negative lens A3 made of the germanium and the positive chalcogen lens A4 are used for the rear lens pair, by which residual axial chromatic aberrations formed by the lenses A1, A2 and the lenses B1, B2 are corrected.