Patent ID: 6999247

Claim:
A wide-angle projection lens comprising, in order from an object side: a first lens group including four lenses and having a negative refractive power; and a second lens group including at least one cemented lens and having a positive refractive power, the first lens group including at least one aspherical lens and including at least one spherical lens having a positive refractive power, the wide-angle projection lens satisfying the following conditional expressions fb/f >3, −2.0 <D 12 /f 1 <−1.3, and 0.8 <Lr/Lf <1.2 wherein f denotes the focal length of the projection lens, fb denotes the retrofocal length of the projection lens, f 1 denotes the focal length of the first lens group, f 2 denotes the focal length of the second lens group, Lf denotes the thickness of the first lens group, Lr denotes the thickness of the second lens group, and D 12 denotes the distance between the first and second lens groups.