ZOOM Russian patent published in 2006 - IPC G02B15/16 G02B9/64 

FIELD: photography; optics.

SUBSTANCE: zoom belongs to objectives with variable focal length and it can be used as video camera's objective providing formation of image onto CCD array. Zoom has four components and aperture diaphragm. First, third and fourth components are positive ones, and the second component is negative one. Aperture diaphragm is disposed in front of the third component; second and fourth components are mounted for movement along optical axis. First component has positive double-cemented lens, which has negative meniscus turned with its convexity to space f objects, and of positive lens. First component also has positive menisci turned with its concaved surface to space of images. Second component has two negative lenses and positive double-glued lens, which is composed of negative menisci turned with its convex surface to space of objects, and of positive lens. First negative lens of second component is biconvex. Positive lens of second component is made in form of menisci turned with its convex surface to space of objects. Third component has positive double-cemented lens, which is composed of biconvex and biconcave lenses, and positive meniscus, which is turned with its concave surface to space of objects. Distance between positive double-cemented lens and menisci of the third component has to be equal or longer than 0,1 focal length of the component. Sum of optical powers of components does not exceed 0,00036 mm-1.

EFFECT: improved quality of image; increased factor of modulation transmission through the whole field of view within whole range of changes in focal lengths.

6 dwg