LENS WITH FOCAL DISTANCE CHANGED DISCRETELY Russian patent published in 2002 - IPC

FIELD: optics. SUBSTANCE: lens includes immobile component and mobile components placed behind it with capability for beams to be input and output from path. Mobile components are manufactured for different focal distances of lens. Immobile component comes in the form of positive meniscus facing object with convexity. Mobile component designed for first focal distance is made in the form of positive lens. First of two components intended for second focal distance has the form of negative meniscus facing object with concavity and second component comprises two positive lenses. Second surface of immobile component can be aspherical. Positive lens of mobile component for first focal distance can come in the form of meniscus facing object with concavity and positive lenses of second mobile component for second focal distance can be produced in the form of meniscuses facing object with concavity. EFFECT: simplified design of lens, expanded field of vision and high quality of image. 3 cl, 5 dwg