ZOOM LENS Russian patent published in 1998 - IPC

FIELD: optical instrumentation. SUBSTANCE: proposed zoom lens includes five components, first one being immobile and manufactured from two positive meniscuses facing object with convexity. Second and third components are mounted for movement along optical axis and are fabricated correspondingly in the form of single biconcave and biconvex lenses. Fourth component is located outside focal plane. Fifth component presents projection system including biconvex lens and first and second positive meniscuses facing object with convexity. Third positive meniscus facing image with convexity is inserted into projection system and is positioned near image plane. First meniscus of first component is single one and second meniscus of same component is cemented together from positive and negative lenses. EFFECT: improved quality of image, increased magnification difference and relative aperture. 1 dwg, 2 tbl