INFRARED RAY ZOOM LENS OR INFRARED RAY MULTIFOCAL LENS, INFRARED RAY IMAGING SYSTEM AND PANORAMIC OBSERVATION OPTICAL SYSTEM

摘要

PROBLEM TO BE SOLVED: To obtain an IR zoom lens or IR multifocal lens or IR imaging, system which has an aspherical surface shape at a prescribed surface with five-group constitution and has high imagery performance over the entire part of a visual field and over the entire part of respective magnification ranges and is small in F value and compact and to obtain a panoramic observation optical system which can be arranged with a compact image rotating correction prism.;SOLUTION: The lens described above is disposed, successively from an object side, with a first lens group G1 which has a focusing function and is positive, a second lens group G2 which has a variable power function and is negative, a third lens group G3 which has a compensation function by accompanying variable power and is positive, a fourth lens group G4 which has a function to form an intermediate image and is positive, a fifth lens group G5 for relay forming the intermediate image on a detecting surface 1, a mask 2 and a Dewar window 3. The fourth lens group G4 and the fifth lens group G5 respectively have at least one aspherical surfaces. The lens satisfies the condition equations (1) 0.5f/f1-41.0 and (2) 2.5f4/f53.0.;COPYRIGHT: (C)2002,JPO