WIDE-ANGLE PROJECTION OBJECTIVE Russian patent published in 2007 - IPC G02B9/64 G02B13/18 

FIELD: optics.

SUBSTANCE: objective contains, in direction from screen plane towards modulator plane, first and second groups of lens elements, flat-parallel plate, prism, flat-parallel plate and aperture diaphragm, situated near the first lens element of the second group. The first group of lens elements has negative optic force and consists of five single lenses - first lens in form of negative meniscus, both surfaces of which are made aspheric, second lens in form of negative meniscus, third biconcave lens, at least one surface of which is made aspheric, fourth biconcave lens and fifth biconvex lens. Second group of lens elements has position optical force and contains five single lenses, first one of which is a position meniscus, second one - negative meniscus, third one - biconvex lens, fourth one - positive meniscus, at least one surface of which is made aspheric, fifth one - positive meniscus, facing the modulator with its convex part.

EFFECT: increased relatively aperture of wide-angle projection objective, decreased value of remaining television distortion.

5 dwg