PROJECTION TYPE ZOOM LENS AND PROJECTION TYPE DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a projection type zoom lens and a projection type display device, having a 5-group and 7-sheet lens configuration, attaining size reduction and reduction of weight, and properly correcting various aberrations, especially, inclination of image plane.;SOLUTION: In this projection type zoom lens, a first negative lens group G₁, and positive second lens groups G₂-fifth lens group G₅ are provided, in the order, from the enlargement side, the reduction side is set substantially telecentric, seven lenses are distributed so that one sheet per the first group G1, one sheet per the second group G2, one sheet per the third group G3, three sheets per the fourth group G4, and one sheet per the fifth group G5; and since at least the third group G3 and the fourth group G4 are taken as moving groups in variable magnification, various aberrations can be improved; despite the simple configuration. An air lens having both convex surfaces is formed between two lenses on the enlargement side constituting the fourth group G4; and since the focal length (power) of the air lens is defined within a predetermined range, especially inclination of image plane can be corrected properly.;COPYRIGHT: (C)2009,JPO&INPIT