| 摘要 |
A wide-angle projection lens includes, 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 a cemented lens and having a positive refractive power. The first lens group includes an aspherical lens and a spherical lens having a positive refractive power. The wide-angle projection lens further includes an iris diaphragm located after the first lens of the second lens group from the object side, and satisfies the following conditional expressions fb/f>3, -2.0<D<SUB>12</SUB>/f<SUB>1</SUB><-1.3, and 0.8<Lr/Lf<1.2 where f denotes the focal length of the projection lens; fb denotes the retrofocal length of the projection lens; f<SUB>1 </SUB>denotes the focal length of the first lens group; Lf denotes the thickness of the first lens group; Lr denotes the thickness of the second lens group; and D<SUB>12 </SUB>denotes the distance between the first and second lens groups.
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