ZOOM LENS FOR PROJECTION AND ENLARGING PROJECTOR

PROBLEM TO BE SOLVED: To realize a zoom lens for projection having excellent performance as a lens for projection used for a three-plate type liquid crystal projector and an enlarging projector using the zoom lens. SOLUTION: The zoom lens for projection to enlarge a planar image P and project and form it on a screen S is constituted by arranging 1st to 6th groups in order from an enlargement side, and the 1st group G1 has negative refractive power, the 2nd group G2 has positive refractive power, the 3rd group G3 has negative refractive power respectively, the 4th and the 5th groups G4 and G5 have positive or negative weak refractive power, and the 6th group G6 has positive refractive power respectively. In the case of varying power, the 1st and the 6th groups G1 and G6 are fixed, and the 2nd, the 3rd, the 4th and the 5th groups G2, G3, G4 and G5 are moved in an optical axis direction. When a projection distance is changed, the image P and the screen surface S are kept conjugate by the movement of the 1st group G1 in the optical axis direction. COPYRIGHT: (C)2004,JPO