PROJECTION LENS AND PROJECTION IMAGE DISPLAY APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a projection lens designed to yield an excellent image having reduced aberrations while keeping a wide viewing angle, an f-number showing sufficient brightness, a long back focus and high telecentricity. SOLUTION: The projection lens includes a first lens group I having negative refractive power on an enlargement side and a second lens group II having positive refractive power on a reduction side with the longest distance in a lens system as a boundary, and is telecentric on the reduction side. The first lens group I comprises a 1A group, a 1B group and a 1C group from the enlargement side, and the second lens group II includes one lens having an aspherical surface and two cemented lenses obtained by sticking three lenses. The back focus: Bf in air when a conjugate point on the enlargement side is infinity, a focal length: f of the entire system, a focal length: f1 of the first lens group and a focal length: f2 of the second lens group satisfy a condition (1) 3.0