VARYING FOCAL DISTANCE OBJECTIVE Russian patent published in 2007 - IPC G02B15/16 

FIELD: optical engineering.

SUBSTANCE: objective has five components. First component is motionless and it is made of two positive menisci turned with their convexity to object. Second meniscus is glued of positive and negative lenses. Second and third components are mounted for movement along optical axis. Second and third components are made in form of single biconcave and biconvex lenses. Fourth component has to be collective, the fifth component is projection system made in form of single biconvex and of three positive menisci; the first and the second menisci are turned with their convexity to object; the third meniscus is turned with its convexity to image. Device also has aperture diaphragm. First meniscus of the second component is glued of single biconvex and biconcave lenses. Positive and negative lenses of second meniscus of first component are made in form of single biconvex and biconvex lenses correspondingly. Aperture diaphragm is placed between biconvex lens and first positive meniscus of fifth component. For that the relation are made which relations are shown in formula of invention defining requirements to materials for making first, second and third components of objective and requirements to designing parameters of objective.

EFFECT: improved precision of image.

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