WIDE-ANGLE PROJECTION LENS Russian patent published in 2005 - IPC

FIELD: optical engineering.

SUBSTANCE: wide-angle projection lens for projecting images formed by DMD and LCD modulators has three groups of lens members, prism, flat-parallel plate and aperture diaphragm disposed in the direction from plane of screen to plane of modulator. The diaphragm is placed between second and third groups of lens members. First group of members has negative focal power, the second and the third groups have positive focal power. First group of lens members is formed by three single lenses - first lens made in form of negative menisci which has both surface to aspherical, second lens made in form of negative menisci and third biconcave lens. Second group of lenses is made in form of single biconvex lens and has one surface to be aspherical. Third group has glued doublet and two single positive lenses.

EFFECT: increased aperture ratio; reduced number of lens members.

5 dwg