| 摘要 |
PROBLEM TO BE SOLVED: To achieve an imaging lens that is sufficiently compact with a half-view angle of approximately 38° and an F number of less than 2.8; sufficiently reduces astigmatism, field curvature, magnification color aberration, color difference by coma aberration, distortion aberration and the like; has a diagonal length of the imaging region of approximately 20 to 45 mm; and has a resolving power applicable to an imaging device with 10 million to 20 million pixels.SOLUTION: An imaging lens comprises a first lens group I, an aperture stop S, and a second lens group II that are arranged sequentially in this order from the object side to the image side. The first lens group I has a positive refractive power or almost afocal, and the second lens group II has a positive refractive power. The first lens group I comprises a first a lens group, a first b lens group, and a first c lens group that are arranged sequentially in this order from the object side to the image side, and the second lens group II comprises a second a lens group, a second b lens group, and a second c lens group that are arranged sequentially in this order from the object side to the image side, and the most outer surface of the second b lens group on the object side is concave, and the most outer surface thereof on the image side is convex. |
