HIGH APERTURE-RATIO LENS (VARIANTS) Russian patent published in 1997 - IPC

FIELD: optical systems of various application. SUBSTANCE: the lens of variant 1 uses a collecting lens, positive doublet cemented of collecting and diverging lenses, converging and diverging menisci with their concavity facing the object, and a converging meniscus with its concavity facing the image. The focal lengths of separate lenses are bound up by definite relations. The lens of variant 2 uses a collecting lens, positive doublet cemented of collecting and diverging lenses, two converging menisci with their concavities facing each other, and a converging meniscus with its concavity facing the image. The focal lengths of separate lenses are bound up by respective relations. EFFECT: improved design. 2 cl, 4 dwg