Imaging Lens

Abstract

An imaging lens comprises, in order from an object side: an aperture stop; a first lens having a positive refractive power in a meniscus form having a convex surface facing toward the object; a second lens having a positive or negative refractive power in a meniscus form having a concave surface facing toward the object; and a third lens having a positive or negative refractive power in an aspheric form at both surfaces, wherein conditional expressions given below are satisfied:

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

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

FIG. 8 is a lens sectional view corresponding to an imaging lens according to example 8 of the invention;

FIG. 9 is a lens sectional view corresponding to an imaging lens according to example 9 of the invention;

FIGS. 10A and 10B are figures showing the lens data of an imaging lens according to example 1 of the invention, wherein FIG. 10A shows the basic lens data and FIG. 10B shows the lens data concerning an aspheric surface;

FIGS. 11A and 11B are figures showing the lens data of an imaging lens according to example 2 of the invention, wherein FIG. 11A shows the basic lens data and FIG. 11B shows the lens data concerning an aspheric surface;

FIGS. 12A and 12B are figures showing the lens data of an imaging lens according to example 3 of the invention, wherein FIG. 12A shows the basic lens data and FIG. 12B shows the lens data concerning an aspheric surface;

FIGS. 13A and 13B are figures showing the lens data of an imaging lens according to example 4 of the invention, wherein FIG. 13A shows the basic lens data and FIG. 13B shows the lens data concerning an aspheric surface;

FIGS. 14A and 14B are figures showing the lens data of an imaging lens according to example 5 of the invention, wherein FIG. 14A shows the basic lens data and FIG. 14B shows the lens data concerning an aspheric surface;

FIGS. 15A and 15B are figures showing the lens data of an imaging lens according to example 6 of the invention, wherein FIG. 15A shows the basic lens data and FIG. 15B shows the lens data concerning an aspheric surface;

FIGS. 16A and 16B are figures showing the lens data of an imaging lens according to example 7 of the invention, wherein FIG. 16A shows the basic lens data and FIG. 16B shows the lens data concerning an aspheric surface;

FIGS. 17A and 17B are figures showing the lens data of an imaging lens according to example 8 of the invention, wherein FIG. 17A shows the basic lens data and FIG. 17B shows the lens data concerning an aspheric surface;

FIGS. 18A and 18B are figures showing the lens data of an imaging lens according to example 9 of the invention, wherein FIG. 18A shows the basic lens data and FIG. 18B shows the lens data concerning an aspheric surface;

FIG. 19 is a figure showing, collectively on each example, the values concerning the conditional expressions;

FIGS. 20A to 20C are aberration diagrams showing the aberrations of the imaging lens according to example 1 of the invention, wherein FIG. 20A shows a spherical aberration, FIG. 20B shows an astigmatism and FIG. 20C shows a distortion;

FIGS. 21A to 21C are aberration diagrams showing the aberrations of the imaging lens according to example 2 of the invention, wherein FIG. 21A shows a spherical aberration, FIG. 21B shows an astigmatism and FIG. 21C shows a distortion;

FIGS. 22A to 22C are aberration diagrams showing the aberrations of the imaging lens according to example 3 of the invention, wherein FIG. 22A shows a spherical aberration, FIG. 22B shows an astigmatism and FIG. 22C shows a distortion;

FIGS. 23A to 23C are aberration diagrams showing the aberrations of the imaging lens according to example 4 of the invention, wherein FIG. 23A shows a spherical aberration, FIG. 23B shows an astigmatism and FIG. 23C shows a distortion;

FIGS. 24A to 24C are aberration diagrams showing the aberrations of the imaging lens according to example 5 of the invention, wherein FIG. 24A shows a spherical aberration, FIG. 24B shows an astigmatism and FIG. 24C shows a distortion;

FIGS. 25A to 25C are aberration diagrams showing the aberrations of the imaging lens according to example 6 of the invention, wherein FIG. 25A shows a spherical aberration, FIG. 25B shows an astigmatism and FIG. 25C shows a distortion;

FIGS. 26A to 26C are aberration diagrams showing the aberrations of the imaging lens according to example 7 of the invention, wherein FIG. 26A shows a spherical aberration, FIG. 26B shows an astigmatism and FIG. 26C shows a distortion;

FIGS. 27A to 27C are aberration diagrams showing the aberrations of the imaging lens according to example 8 of the invention, wherein FIG. 27A shows a spherical aberration, FIG. 27B shows an astigmatism and FIG. 27C shows a distortion; and

FIGS. 28A to 28C are aberration diagrams showing the aberrations of the imaging lens according to example 9 of the invention, wherein FIG. 28A shows a spherical aberration, FIG. 28B shows an astigmatism and FIG. 28C shows a distortion.

Claims

1. An imaging lens comprising, in order from an object side: an aperture stop;a first lens having a positive refractive power in a meniscus form having a convex surface facing toward the object;a second lens having a positive or negative refractive power in a meniscus form having a concave surface facing toward the object; anda third lens having a positive or negative refractive power in an aspheric form at both surfaces,wherein conditional expressions given below are satisfied: vd1>50  (1)vd3>50  (2)0.7<f1/f<1.0  (3)−0.9<f2/{f3·(45−vd2)}<0.4  (4)

2. An image lens according to claim 1, wherein the second lens and the third lens are plastic lenses.

3. An image lens according to claim 1, wherein the third lens has a surface closer to an image formed concave in form at and around an optical axis and convex in form at an periphery thereof.

4. An image lens according to claim 3, wherein the third lens has a surface closer to an image formed concave in form at and around an optical axis and convex in form at an periphery thereof.