| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact imaging lens which has a brightness of F2.5 or less, and corrects various aberrations well while achieving a wide angle of view, at low cost.SOLUTION: The imaging lens includes, in order from the object side to the image side: an aperture stop ST; a first lens L1 having a positive refractive power; a second lens L2 having a negative refractive power; a third lens L3 having a positive or negative refractive power; a fourth lens L4 having a positive refractive power; and a fifth lens L5 which has a negative refractive power and whose both surfaces are aspherical. The imaging lens satisfies the following conditional expressions: (1) TTL/2ih≤0.8, (2) 1.60<Nd3<1.70, and (3) 4.0<|r9/r10|<14.0, where TTL is the entire optical length, ih is the maximum image height, Nd3 is the refractive index of the third lens at the d-line, r9 is the curvature radius of the object side surface of the fifth lens, and r10 is the curvature radius of the image side surface of the fifth lens.SELECTED DRAWING: Figure 1 |
