| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a compact imaging lens which has sufficient brightness and has satisfactorily corrected various aberrations, and is composed of five lenses.SOLUTION: The imaging lens comprises, in order from an object side: a first lens L1 which has positive refractive power and has a convex surface facing the object side; a second lens L2 which has negative refractive power and has a shape in which the object-side surface thereof has a concave surface facing the object side and the image-side surface thereof has a convex surface facing an image side, or is infinite; a third lens L3 which has positive refractive power; a fourth lens L4 which has negative refractive power and has a concave surface facing the image side; and a fifth lens L5 which has positive refractive power and has a concave surface facing the image side. The image-side surface of the fifth lens L5 has an aspherical shape and has an inflection point in a position other than an intersection with an optical axis. The imaging lens satisfies the following conditional expressions: -0.60<f1/f45<-0.25 (1) and 0.1<f/f3<1.0 (2), where f1 is the focal length (mm) of the first lens L1, f45 is the composite focal length (mm) of the fourth lens L4 and the fifth lens L5, f is the focal length (mm) of the entire system of the imaging lens, and f3 is the focal length (mm) of the third lens L3.</p> |
