| 摘要 |
An imaging lens substantially consists of a first-lens-group, a stop and a second-lens-group in this order from object-side. The first-lens-group substantially consists of a 1-1st-lens having negative-refractive-power and a meniscus-shape with its convex-surface facing object-side and a 1-2nd-lens having positive-refractive-power, and an object-side-lens-surface of which has a convex-shape facing object-side, in this order from object-side. The second-lens-group substantially consists of a 2-1st-lens having positive-refractive-power and a meniscus-shape with its convex-surface facing image-side, a 2-2nd-lens having negative-refractive-power, and an object-side-lens-surface of which has a concave-shape facing object-side, and the absolute-value of a curvature-radius of the object-side-lens-surface of which is less than the absolute-value of a curvature-radius of an image-side-lens-surface thereof, and a 2-3rd-lens having positive-refractive-power, and an object-side-lens-surface of which has a convex-shape facing object-side, in this order from object-side. A conditional-formula about an average of refractive-indices of the 1-2nd-lens, the 2-1st-lens and the 2-3rd-lens for d-line is satisfied. |
| 主权项 |
1. An imaging lens substantially consisting of:
a first lens group; a stop; and a second lens group in this order from an object side, wherein the first lens group substantially consists of a 1-1st lens having negative refractive power and a meniscus shape with its convex surface facing the object side and a 1-2nd lens having positive refractive power, and an object-side lens surface of which has a convex shape facing the object side, in this order from the object side, and wherein the second lens group substantially consists of a 2-1st lens having positive refractive power and a meniscus shape with its convex surface facing an image side, a 2-2nd lens having negative refractive power, and an object-side lens surface of which has a concave shape facing the object side, and the absolute value of a curvature radius of the object-side lens surface of which is less than the absolute value of a curvature radius of an image-side lens surface thereof, and a 2-3rd lens having positive refractive power, and an object-side lens surface of which has a convex shape facing the object side, in this order from the object side, and wherein the following conditional formula (5) is satisfied:
Ndp>1.75 (5), where Ndp: an average of refractive indices of the 1-2nd lens, the 2-1st lens and the 2-3rd lens for d-line. |
