Imaging lens

Abstract

An imaging lens includes first to third lenses G1 to G3 arranged in order from a object side. The first lens has a biconvex shape in a vicinity of an optical axis Z1. The second lens has a concave surface facing a object side. The second lens has a negative refractive power. The third lens has a positive or negative refractive power and has a meniscus shape containing, in a vicinity of the optical axis, a convex surface facing the object side. The following conditional expression is satisfied:

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lens sectional view of an imaging lens according to an example 1 of the invention.

FIG. 2 is a lens sectional view of an imaging lens according to an example 2 of the invention.

FIG. 3 is a lens sectional view of an imaging lens according to an example 3 of the invention.

FIG. 4 is a lens sectional view of an imaging lens according to an example 4 of the invention.

FIG. 5 is a lens sectional view of an imaging lens according to an example 5 of the invention.

FIG. 6 is a lens sectional view of an imaging lens according to an example 6 of the invention.

FIG. 7 is a lens sectional view of an imaging lens according to an example 7 of the invention.

FIG. 8 is a view showing lens data of the imaging lens according to the example 1 of the invention, FIG. 8A shows basic lens data and FIG. 8B shows lens data regarding aspheric surfaces.

FIG. 9 is a view showing lens data of the imaging lens according to the example 2 of the invention, FIG. 9A shows basic lens data and FIG. 9B shows lens data regarding aspheric surfaces.

FIG. 10 is a view showing lens data of the imaging lens according to the example 3 of the invention, FIG. 10A shows basic lens data and FIG. 10B shows lens data regarding aspheric surfaces.

FIG. 11 is a view showing lens data of the imaging lens according to the example 4 of the invention, FIG. 11A shows basic lens data and FIG. 11B shows lens data regarding aspheric surfaces.

FIG. 12 is a view showing basic lens data of the imaging lens according to the example 5.

FIG. 13 is a view showing lens data regarding aspheric surfaces of the imaging lens according to the example 5.

FIG. 14 is a view showing basic lens data of the imaging lens according to the example 6.

FIG. 15 is a view showing lens data regarding aspheric surfaces of the imaging lens according to the example 6.

FIG. 16 is a view showing lens data of the imaging lens according to the example 7 of the invention, FIG. 16A shows basic lens data and FIG. 16B shows lens data regarding aspheric surfaces.

FIG. 17 is a view showing values regarding conditional expressions in respective examples collectively.

FIG. 18 is aberration charts showing various aberrations of the imaging lens according to the example 1 of the invention, FIG. 18A shows a spherical aberration, FIG. 18B shows astigmatism and FIG. 18C shows a distortion.

FIG. 19 is aberration charts showing various aberrations of the imaging lens according to the example 2 of the invention, FIG. 19A shows a spherical aberration, FIG. 19B shows astigmatism and FIG. 19C shows a distortion.

FIG. 20 is aberration charts showing various aberrations of the imaging lens according to the example 3 of the invention, FIG. 20A shows a spherical aberration, FIG. 20B shows astigmatism and FIG. 20C shows a distortion.

FIG. 21 is aberration charts showing various aberrations of the imaging lens according to the example 4 of the invention, FIG. 21A shows a spherical aberration, FIG. 21B shows astigmatism and FIG. 21C shows a distortion.

FIG. 22 is aberration charts showing various aberrations of the imaging lens according to the example 5 of the invention, FIG. 22A shows a spherical aberration, FIG. 22B shows astigmatism and FIG. 22C shows a distortion.

FIG. 23 is aberration charts showing various aberrations of the imaging lens according to the example 6 of the invention, FIG. 23A shows a spherical aberration, FIG. 23B shows astigmatism and FIG. 23C shows a distortion.

FIG. 24 is aberration charts showing various aberrations of the imaging lens according to the example 7 of the invention, FIG. 24A shows a spherical aberration, FIG. 24B shows astigmatism and FIG. 24C shows a distortion.

Claims

1. An imaging lens comprising: a first lens having a biconvex shape in a vicinity of an optical axis;a second lens having a concave surface facing a object side, the second lens having a negative refractive power; anda third lens having a positive or negative refractive power and having a meniscus shape containing, in a vicinity of the optical axis, a convex surface facing the object side, wherein:the first lens, the second lens and the third lens are arranged in order from the object side,at least one of surfaces of the first to third lenses is aspherical, andthe following conditional expression is satisfied: 0.7<f1/f<1.30.2<D2/f<0.5

2. The lens according to claim 1, wherein the following conditional expression is further satisfied: 0.3<|f2/f|<1.00.5<f3/f<1.0

3. The lens according to claim 1, wherein the following conditional expression is further satisfied: 20<v1−v2

4. The lens according to claim 2, wherein the following conditional expression is further satisfied: 20<v1−v2

5. The lens according to claim 1, wherein the second lens has a meniscus shape in a vicinity of the optical axis.

6. The lens according to claim 2, wherein the second lens has a meniscus shape in a vicinity of the optical axis.

7. The lens according to claim 3, wherein the second lens has a meniscus shape in a vicinity of the optical axis.

8. The lens according to claim 4, wherein the second lens has a meniscus shape in a vicinity of the optical axis.

9. The lens according to claim 1, wherein the second lens has a biconcave shape in a vicinity of the optical axis.

10. The lens according to claim 2, wherein the second lens has a biconcave shape in a vicinity of the optical axis.

11. The lens according to claim 3, wherein the second lens has a biconcave shape in a vicinity of the optical axis.

12. The lens according to claim 4, wherein the second lens has a biconcave shape in a vicinity of the optical axis.