Imaging lens

Abstract

There is provided an imaging lens with high resolution which satisfies in well balance low-profileness, wide field of view and low F-number. An imaging lens comprises in order from an object side to an image side, a first lens being double-sided aspheric lens, a second lens having positive or negative refractive power, an aperture stop, a third lens having positive refractive power, a fourth lens having at least one aspheric surface and negative refractive power, a fifth lens having at least one aspheric surface and positive or negative refractive power, and a sixth lens being double-sided aspheric lens and having positive refractive power, wherein an image-side surface of said sixth lens is a concave surface facing the image side near the optical axis and is formed as the aspheric surface, which changes from the concave surface to the convex surface at an area apart from the optical axis.

Claims

1. An imaging lens comprising in order from an object side to an image side, a first lens being a double-sided aspheric lens, a second lens, an aperture stop, a third lens having a convex surface facing the image side near the optical axis, a fourth lens, a fifth lens, and a sixth lens being a double-sided aspheric lens and having positive refractive power, wherein the sixth lens is a meniscus lens having a concave surface facing the image side near the optical axis and being formed as the aspheric surface, which changes to convex surface at an area apart from the optical axis, and the following conditional expressions (1) and (10) are satisfied:
0.6<t23/t34<1.6  (1)
25<|νd 3−νd 4|<45  (10) where t23: a distance along the optical axis from the image-side surface of the second lens to the object-side surface of the third lens, t34: a distance along the optical axis from the image-side surface of the third lens to the object-side surface of the fourth lens, vd3: an abbe number at d-ray of the third lens, and vd4: an abbe number at d-ray of the fourth lens.

2. An imaging lens according to claim 1, wherein the second lens has positive or negative refractive power, and the third lens has positive refractive power.

3. An imaging lens according to claim 1, wherein the fourth lens has at least one aspheric surface and negative refractive power.

4. An imaging lens according to claim 1, wherein the fifth lens has at least one aspheric surface and positive or negative refractive power.

5. An imaging lens according to claim 1, wherein the object-side surface of the first lens is a plane or a concave surface facing the object side near the optical axis.

6. An imaging lens according to claim 1, wherein the image-side surface of the first lens is a plane or a convex surface facing the image side near the optical axis.

7. An imaging lens according to claim 5, wherein the object-side surface of the first lens is formed as the aspheric surface which changes to convex surface at a peripheral area.

8. An imaging lens according to claim 6, wherein the image-side surface of the first lens is formed as the aspheric surface, which changes to concave surface at the peripheral area.

9. An imaging lens according to claim 1, wherein the second lens is a meniscus lens having a concave surface facing the image side near the optical axis, the third lens has a convex surface facing the object-side near the optical axis, the fourth lens is a meniscus lens having a concave surface facing the object side near the optical axis, and the fifth lens is a meniscus lens having a concave surface facing the object side near the optical axis.

10. An imaging lens according to claim 1, wherein the sixth lens has a convex surface facing the object side near the optical axis and being formed as the aspheric surface which changes from convex surface to concave surface at an area apart from the optical axis.

11. An imaging lens according to claim 1, wherein the following conditional expressions (2) and (3) are satisfied:
−0.3<(Nd1−1)/r1≤0.0  (2)
0.0≤(1−Nd1)/r2<0.3  (3) where Nd1: refractive index at d-ray of the first lens, r1: curvature radius near the optical axis of the object-side surface of the first lens, and r2: curvature radius near the optical axis of the image-side surface of the first lens.

12. An imaging lens according to claim 1, wherein the following conditional expression (4) is satisfied:
3.0<|f2/f|  (4) where f: a focal length of the overall optical system of the imaging lens, and f2: a focal length of the second lens.

13. An imaging lens according to claim 1, wherein the following conditional expression (5) is satisfied:
0.5<f3/f<1.5  (5) where f: a focal length of the overall optical system of the imaging lens, and f3: a focal length of the third lens.

14. An imaging lens according to claim 1, wherein the following conditional expression (6) is satisfied:
−2.5<f4/f<−0.8  (6) where f: focal length of the overall optical system of the imaging lens, and f4: focal length of the fourth lens.

15. An imaging lens according to claim 1, wherein the following conditional expression (7) is satisfied:
15<|f5/f|  (7) where f: a focal length of the overall optical system of the imaging lens, and f5: a focal length of the fifth lens.

16. An imaging lens according to claim 1, wherein the following conditional expression (8) is satisfied:
1.0<f6/f<2.0  (8) where f: a focal length of the overall optical system of the imaging lens, and f6: a focal length of the sixth lens.

17. An imaging lens according to claim 1, wherein the following conditional expression (9) is satisfied:
18<νd 2<28  (9) where vd2: an abbe number at d-ray of the second lens.

18. An imaging lens according to claim 1, wherein the following conditional expression (11) is satisfied:
0.6<TTL/2ih<1.0  (11) where TTL: total track length, and ih: maximum image height.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view showing a general configuration of an imaging lens in Example 1 according to the present invention;

(2) FIG. 2 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 1 according to the present invention;

(3) FIG. 3 is a schematic view showing the general configuration of an imaging lens in Example 2 according to the present invention;

(4) FIG. 4 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 2 according to the present invention;

(5) FIG. 5 is a schematic view showing the general configuration of an imaging lens in Example 3 according to the present invention;

(6) FIG. 6 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 3 according to the present invention;

(7) FIG. 7 is a schematic view showing the general configuration of an imaging lens in Example 4 according to the present invention;

(8) FIG. 8 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 4 according to the present invention;

(9) FIG. 9 is a schematic view showing the general configuration of an imaging lens in Example 5 according to the present invention; and

(10) FIG. 10 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 5 according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(11) Hereinafter, the preferred embodiment of the present invention will be described in detail referring to the accompanying drawings.

(12) FIGS. 1, 3, 5, 7 and 9 are schematic views showing the general configurations of the imaging lenses in Examples 1 to 5 according to the embodiments of the present invention, respectively. Since all these examples have the same basic lens configuration, the general configuration of an imaging lens according to this embodiment is explained below mainly referring to the schematic view of Example 1.

(13) As shown in FIG. 1, an imaging lens according to this embodiment comprises in order from an object side to an image side, a first lens L1 being double-sided aspheric lens, a second lens L2 having positive or negative refractive power, an aperture stop STO, a third lens L3 having the positive refractive power, a fourth lens L4 having at least one aspheric surface and the negative refractive power, a fifth lens L5 having at least one aspheric surface and the positive or negative refractive power, and a sixth lens L6 being the double-sided aspheric lens and having the positive refractive power, wherein an image-side surface of the sixth lens L6 is a concave surface facing the image side near an optical axis X and is formed as the aspheric surface, which changes to a convex surface at an area apart from the optical axis X.

(14) A filter IR such as an IR cut filter and a cover glass is located between the sixth lens L6 and an image plane IMG (namely, the image plane of the imaging lens). The filter IR is omissible.

(15) By using the double-sided aspheric lens, the first lens L1 excellently corrects the aberration for light ray incident from wide field of view from a center to off-axis area. In FIG. 1, the first lens L1 has planes facing the object side and the image side near the optical axis X, and substantively has no refractive power near the optical axis X. A shape of the first lens L1, however, is not limited thereto. As shown in FIG. 3, the first lens L1 may have a shape of plane-convex shape of which the object-side surface is the plane and the image-side surface is convex near the optical axis X. Furthermore, as shown in FIGS. 5 to 9, the first lens L1 may have a meniscus shape of which the object-side surface is concave and the image-side surface is convex near the optical axis X.

(16) As a shape of the first lens L1 near the optical axis, the first lens L1 has the object-side surface being the plane surface or the concave surface and the image-side surface being the plane surface or the convex surface, therefore a position of principal point is moved toward the image side. Therefore, if focal length of an overall optical system is shortened, coping with the wide field of view, required back focus is ensured.

(17) Furthermore, the object-side surface of the first lens L1 is formed as the aspheric surface, which changes to the convex surface at the peripheral area, and the image-side surface is formed as the aspheric surface, which changes to the concave surface at the peripheral area. The convex surface at the peripheral area of the object-side surface has the pole point, and the concave surface of the peripheral area of the image-side surface also has the pole point.

(18) Thus configured as the aspheric surfaces, the light ray incident to the peripheral area is entered at an angle near a normal line of the lens surface of the object side, and the light ray emitted from the peripheral area is emitted at an angle near a normal line of the lens surface of the image side. Thereby, occurrence of the high-order aberration is prevented. By having the pole point, an amount of Sag is reduced, and contribution to the low-profileness is made. Furthermore, such shape of the lens is symmetrical with respect to a shape of the sixth lens L6 of the last lens, and distortion is excellently corrected accordingly.

(19) The second lens L2 is a meniscus lens having the concave surface facing the image side and has the positive refractive power, and excellently corrects the spherical aberration and the coma aberration occurred at the first lens L1. The refractive power of the second lens L2 may be, as shown in FIGS. 3 to 9, the negative refractive power when the first lens L1 has the positive refractive power. In this case, the chromatic aberration is excellently corrected.

(20) The aperture stop STO is arranged between the second lens L2 and the third lens L3, namely at a position near a center area of an optical system. Therefore, symmetry is made across the aperture stop, and distortion increased according to the wide field of view is reduced.

(21) The third lens L3 has biconvex shape having convex surfaces facing the object side and the image side, and has the positive refractive power. By having the biconvex shape, the third lens L3 achieves the low-profileness. The lens having main positive refractive power is arranged near the center area of the optical system, and therefore it becomes easy to balance the aberrations of the overall optical system. Furthermore, the third lens has the biconvex shape, and curvature is suppressed from being large and sensitivity to manufacturing error is reduced.

(22) The fourth lens L4 is a meniscus lens having the concave surface facing the object side near the optical axis, and has the negative refractive power. At least one aspheric surface is provided, and the astigmatism is corrected while correcting the chromatic aberration.

(23) The fifth lens L5 is a meniscus lens having the concave surface facing the object side near the optical axis, and has the negative refractive power. At least one aspheric surface is provided, and the astigmatism occurred according to the wide field of view is excellently corrected. The refractive power of the fifth lens L5 may be positive as shown in FIG. 9.

(24) The sixth lens L6 is a meniscus lens having the concave surface facing the image side near the optical axis X. Also, the sixth lens L6 is the double-sided aspheric lens and has the positive refractive power, and ensures the back focus while maintaining the low-profileness. The aspheric surface is formed as the image-side surface is the concave surface facing the image side near the optical axis X, which changes to the convex surface facing the image side at an area apart from the optical axis X. Therefore, there are achieved the field curvature correction, distortion correction and control of an angle of light ray incident to the image sensor. The aspheric surface is also formed as the object-side surface of the sixth lens L6 is the convex surface facing the object side near the optical axis X, which changes to the concave surface facing the object side at an area apart from the optical axis X. The sixth lens L6 controls an angle of the light ray incident to the image sensor as well as the image-side surface. Furthermore, by gradually changing from the convex surface to the concave surface, the field curvature at middle image height is excellently suppressed.

(25) The imaging lens according to the present embodiments shows preferable effect by satisfying the below conditional expressions (1) to (13).
0.6<t23/t34<1.6  (1)
−0.3<(Nd1−1)/r1≤0.0  (2)
0.0≤(1−Nd1)/r2<0.3  (3)
3.0<|f2/f|  (4)
0.5<f3/f<1.5  (5)
−2.5<f4/f<−0.8  (6)
15<|f5/f|  (7)
1.0<f6/f<2.0  (8)
18<νd 2<28  (9)
25<|νd 3−νd 4|<45  (10)
0.6<TTL/2ih<1.0  (11)
0.8<(L1F−L3F)/(L3R−L5R)<1.2  (12)
0.2<EPD/TTL<0.4  (13)
where
t23: distance along the optical axis between the second lens L2 and the third lens L3,
t34: distance along the optical axis between the third lens L3 and the fourth lens L4,
Nd1: refractive index at d-ray of the first lens L1,
r1: curvature radius near the optical axis of the object-side surface of the first lens L1,
r2: curvature radius near the optical axis of the image-side surface of the first lens L1,
f: focal length of the overall optical system of the imaging lens,
f2: focal length of the second lens L2,
f3: focal length of the third lens L3,
f4: focal length of the fourth lens L4,
f5: focal length of the fifth lens L5,
f6: focal length of the sixth lens L6,
νd2: abbe number at d-ray of the second lens L2,
νd3: abbe number at d-ray of the third lens L3,
νd4: abbe number at d-ray of the fourth lens L4,
TTL: total track length,
ih: maximum image height,
(L1F−L3F): distance along the optical axis from the object-side surface of the first lens L1 to the object-side surface of the third lens L3,
(L3R−L5R): distance along the optical axis from the image-side surface of the third lens L3 to the image-side surface of the fifth lens L5, and EPD: entrance pupil diameter.

(26) Regarding the imaging lens according to the present embodiments, it is preferable to satisfy all of conditional expressions. By satisfying the conditional expression individually, operational advantage corresponding to each conditional expression can be obtained.

(27) In this embodiment, the aspheric shapes of the surfaces of the aspheric lens are expressed by Equation 1, where Z denotes an axis in the optical axis direction, H denotes a height perpendicular to the optical axis, R denotes a curvature radius, k denotes a conic constant, and A4, A6, A8, A10, A12, A14, and A16 denote aspheric surface coefficients.

(28) $\begin{array}{cc}Z=\frac{\frac{H^2}{R}}{1+\sqrt{1-\left(k+1\right)\frac{H^2}{R^2}}}+A_4{H}^4+A_6{H}^6+A_8{H}^8+A_{10}{H}^{10}+A_{12}{H}^{12}+A_{14}{H}^{14}+A_{16}{H}^{16}& \mathrm{Equation}1\end{array}$

(29) Next, examples of the imaging lens according to this embodiment will be explained. In each example, f denotes the focal length of the overall optical system of the imaging lens, Fno denotes an F-number, w denotes a half field of view, ih denotes a maximum image height (length of diagonal line of the effective image plane of the image sensor) a, TTL denotes the total track length, and EPD denotes an entrance pupil diameter. Additionally, i denotes surface number counted from the object side, r denotes a curvature radius, d denotes the distance of lenses along the optical axis (surface distance), Nd denotes a refractive index at d-ray (reference wavelength), and νd denotes an abbe number at d-ray. As for aspheric surfaces, an asterisk (*) is added after surface number i.

Example 1

(30) The basic lens data is shown below in Table 1.

Example 1

(31) TABLE-US-00001 Unit mm f = 2.71 Fno = 1.82 ω(°) = 50.0 ih = 3.26 TTL = 4.82 EPD = 1.48 Surface Data Surface Curvature Surface Refractive Abbe Number Number i Radius r Distance d Index Nd νd (Object) Infinity Infinity  1* Infinity 0.4368 1.5443 55.865 (=νd1)  2* Infinity 0.0200  3* 1.1789 0.2986 1.6607 20.365 (=νd2)  4* 1.0798 0.2649 5(Stop) Infinity 0.0465  6* 3.6614 0.6661 1.5348 55.664 (=νd3)  7* −2.0997 0.3862  8* −1.0976 0.2500 1.6607 20.365 (=νd4)  9* −1.7223 0.0207 10* −1.2441 0.4136 1.5443 55.865 (=νd5) 11* −1.4549 0.0200 12* 1.0336 0.8570 1.5348 55.664 (=νd6) 13* 1.2701 0.4000 14  Infinity 0.2100 1.5168 64.198 15  Infinity 0.6290 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 1 Infinity 2 3 97.573 3 6 2.600 4 8 −5.447 5 10 −51.108 6 12 4.588 Aspheric Surface Data First Surface Second Surface Third Surface Fourth Surface Sixth Surface Seventh Surface k −1.000000E+00 −1.000000E+00   0.000000E+00   0.000000E+00   0.000000E+00   1.403170E+00 A4    1.797726E−01   1.723351E−01 −2.681040E−01 −3.850807E−01 −2.036931E−02 −1.627902E−01 A6  −1.492221E−01 −3.832891E−02   2.909194E−01   1.180462E+00   5.557822E−02   3.293751E−02 A8    1.417201E−01 −1.435741E−01 −9.814161E−01 −6.690402E+00 −1.003922E+00 −1.294590E−01 A10 −7.913961E−02   2.607346E−01   1.506531E+00   2.407548E+01   4.352207E+00 −7.001897E−01 A12   1.599723E−02 −1.942422E−01 −1.505163E+00 −5.106573E+01 −1.063761E+01   2.325505E+00 A14   5.999273E−03   5.797865E−02   9.761256E−01   5.722652E+01   1.291587E+01 −2.743487E+00 A16 −2.750486E−03 −4.807202E−03 −2.854355E−01 −2.384692E+01 −5.838213E+00   1.203458E+00 Eighth Surface Ninth Surface Tenth Surface Eleventh Surface Twelfth Surface Thirteenth Surface k   0.000000E+00 −1.302504E+01   0.000000E+00   0.000000E+00 −7.061867E+00 −7.737889E−01 A4  −1.075862E+00 −8.592702E−01   1.314801E+00   9.599146E−02 −1.316273E−01 −2.690929E−01 A6    4.177164E+00   2.769483E+00 −3.027174E+00 −6.713019E−02   6.960129E−03   1.201489E−01 A8  −1.128232E+01 −6.80.5663E+00   4.844819E+00   2.417825E−01   4.145650E−02 −4.605633E−02 A10   2.112385E+01   1.025397E+01 −5.460944E+00 −4.299786E−01 −2.578706E−02   1.218458E−02 A12 −2.313308E+01 −8.726281E+00   4.083692E+00   3.698411E−01   7.259932E−03 −2.084441E−03 A14   1.371548E+01   3.933660E+00 −1.776140E+00 −1.488675E−01 −1.012093E−03   2.024134E−04 A16 −3.419862E+00 −7.362971E−01   3.400999E−01   2.357099E−02   5.640213E−05 −8.444662E−06

(32) The imaging lens in Example 1 satisfies conditional expressions (1) to (13) as shown in Table 6.

(33) FIG. 2 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 1. The spherical aberration diagram shows the amount of aberration at wavelengths of F-ray (486 nm), d-ray (588 nm), and C-ray (656 nm). The astigmatism diagram shows the amount of aberration at d-ray on a sagittal image surface S and on tangential image surface T, respectively (same as FIG. 4, FIG. 6, FIG. 8 and FIG. 10). As shown in FIG. 2, each aberration is corrected excellently.

Example 2

(34) The basic lens data is shown below in Table 2.

Example 2

(35) TABLE-US-00002 Unit mm f = 2.69 Fno = 1.82 ω(°) = 50.0 ih = 3.26 TTL = 4.83 EPD = 1.48 Surface Data Surface Curvature Surface Refractive Abbe Number Number i Radius r Distance d Index Nd νd (Object) Infinity Infinity  1* Infinity 0.4766 1.6142 25.577 (=νd1)  2* −5.9956 0.0200  3* 1.3052 0.2500 1.6607 20.365 (=νd2)  4* 0.9812 0.2541 5(Stop) Infinity 0.0723  6* 3.4491 0.6337 1.5348 55.664 (=νd3)  7* −1.8585 0.3975  8* −1.0736 0.3000 1.6607 20.365 (=νd4)  9* −2.0263 0.0202 10* −1.2985 0.3791 1.5443 55.865 (=νd5) 11* −1.4836 0.0200 12* 1.0082 0.8803 1.5348 55.664 (=νd6) 13* 1.2991 0.4000 14  Infinity 0.2100 1.5168 64.198 15  Infinity 0.6087 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 1 9.761 2 3 −8.631 3 6 2.356 4 8 −3.951 5 10 −68.834 6 12 4.098 Aspheric Surface Data First Surface Second Surface Third Surface Fourth Surface Sixth Surface Seventh Surface k −1.000000E+00 −1.000000E+00   0.000000E+00   0.000000E+00   0.000000E+00   6.586469E−01 A4   1.432259E−01   3.347359E−01 −2.462888E−01 −6.479659E−01 −1.322072E−02 −1806816E−01 A6 −1.211465E−01 −5.383549E−01   2.477404E−01   1.831641E+00 −1.468350E−01   2.835088E−01 A8   1.379664E−01   8.140234E−01 −1.483750E+00 −8.919506E+00   9.895538E−01 −1.671818E+00  A10 −1.146546E−01 −8.981354E−01   3.557731E+00   2.855813E+01 −5.773549E+00   4.521650E+00  A12   6.153994E−02   6.590858E−01 −4.626762E+00 −5.386613E+01   1.571873E+01 −7.306848E+00  A14 −1.798073E−02 −2.856580E−01   3.253411E+00   5.308414E+01 −2.166088E+01   6.116149E+00  A16   2.102694E−03   5.431178E−02 −9.439993E−01 −1.834716E+01   1.232131E+01 −1.941399E+00 Eighth Surface Ninth Surface Tenth Surface Eleventh Surface Twelfth Surface Thirteenth Surface k   0.000000E+00 −1.299367E+01   0.000000E+00   0.000000E+00 −8.268465E+00 −7.602346E−01 A4 −8.379216E−01 −9.042880E−01   9.533473E−01 −1.865154E−02 −1.692933E−01 −2.719961E−01 A6   2.659732E+00   2.958174E+00 −1.479618E+00   2.458213E−01   9.944472E−02   1.247516E−01 A8 −5.943567E+00 −6.929414E+00   1.663691E+00   1.979642E−01 −4.301596E−02 −4.762595E−02  A10   9.826717E+00   9.493128E+00 −1.514714E+00 −7.831807E−01   1.368863E−02   1.199900E−02  A12 −8.956667E+00 −7.319193E+00   9.620160E−01   7.078698E−01 −2.794975E−03 −1.907234E−03  A14   4.308540E+00   3.061849E+00 −3.480073E−01 −2.717305E−01   3.179394E−04   1.722042E−04  A16 −8.792719E−01 −5.492515E−01   5.842055E−02   3.943808E−02 −1.511600E−05 −6.801414E−06

(36) The imaging lens in Example 2 satisfies conditional expressions (1) to (13) as shown in Table 6.

(37) FIG. 4 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 2. As shown in FIG. 4, each aberration is corrected excellently.

Example 3

(38) The basic lens data is shown below in Table 3.

Example 3

(39) TABLE-US-00003 Unit mm f = 2.69 Fno = 1.82 ω(°) = 49.9 ih = 3.26 TTL = 4.80 EPD = 1.40 Surface Data Surface Curvature Surface Refractive Abbe Number Number i Radius r Distance d Index Nd νd (Object) Infinity  1* −4.5289 0.4208 1.6142 25.577 (=νd1)  2* −2.5820 0.0200  3* 1.3537 0.2648 1.6607 20.365 (=νd2)  4* 1.0300 0.2277 5(Stop) Infinity 0.1261  6* 3.4084 0.6237 1.5348 55.664 (=νd3)  7* −1.8963 0.3969  8* −1.1080 0.3000 1.6607 20.365 (=νd4)  9* −2.2929 0.0215 10* −1.3959 0.3849 1.5163 58.421 (=νd5) 11* −1.5929 0.0200 12* 1.0301 0.8811 1.5348 55.664 (=νd6) 13* 1.3471 0.4000 14  Infinity 0.2100 1.5168 64.198 15  Infinity 0.5958 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 1 9.036 2 3 −9.667 3 6 2.376 4 8 −3.608 5 10 −66.617 6 12 4.158 Aspheric Surface Data First Surface Second Surface Third Surface Fourth Surface Sixth Surface Seventh Surface k −1.000000E+00 −1.000000E+00   0.000000E+00   0.000000E+00   0.000000E+00   3.056868E−01 A4   1.767867E−01   3.357545E−01 −2.999942E−01 −7.335992E−01 −1.556505E−02 −1.776825E−01 A6 −1.736935E−01 −4.913865E−01   5.099147E−01   2.436469E+01 −1.207468E−01   1.662706E−01 A8   1.718513E−01   6.464306E−01 −1.920762E+00 −1.148353E+01   4.999901E−01 −5.626863E−01  A10 −1.194623E−01 −5.929907E−01   4.271614E+00   3.809621E+01 −2.189721E+00   1.492138E−01  A12   5.259858E−02   3.435122E−01 −5.635129E+00 −7.802054E+01   4.485661E+00   1.748822E+00  A14 −1.300566E−02 −1.122969E−01   4.053875E+00   8.737067E+01 −5.492830E+00 −3.304127E+00  A16   1.362416E−03   1.571463E−02 −1.201422E+00 −3.961802E+01   3.251532E+00   1.898396E+00 Eighth Surface Ninth Surface Tenth Surface Eleventh Surface Twelfth Surface Thirteenth Surface k   0.000000E+00 −1.343320E+01   0.000000E+00   0.000000E+00 −8.766421E+00 −7.479152E−01 A4 −8.554883E−01 −9.957579E−01   8.069601E−01   3.879057E−02 −1.380973E−01 −2.516710E−01 A6   2.507261E+00   3.378474E+00 −7.965785E−01   2.187401E−01   2.347262E−02   1.057362E−01 A8 −4.475403E+00 −7.654879E+00 −1.115848E−02 −9.400703E−02   1.550108E−02 −3.838012E−02  A10   5.896195E+00   1.050514E+01   8.641389E−01 −1.9169736−01 −8.545558E−03   9.3979656−03  A12 −4.142820E+00 −8.404342E+00 −9.533548E−01   2.296693E−01   1.871797E−03 −1.456235E−03  A14   1.415485E+00   3.704254E+00   4.575786E−01 −9.245063E−02 −2.058015E−04   1.278177E−04  A16 −1.821261E−01 −6.958314E−01 −8.181535E−02   1.315855E−02   9.506637E−06 −4.914545E−06

(40) The imaging lens in Example 3 satisfies conditional expressions (1) to (13) as shown in Table 6.

(41) FIG. 6 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 3. As shown in FIG. 6, each aberration is corrected excellently.

Example 4

(42) The basic lens data is shown below in Table 4.

Example 4

(43) TABLE-US-00004 Unit mm f = 2.69 Fno = 1.82 ω(°) = 50.0 ih = 3.26 TTL = 4.82 EPD = 1.48 Surface Data Surface Curvature Surface Refractive Abbe Number Number i Radius r Distance d Index Nd νd (Object) Infinity Infinity  1* −5.9650 0.4225 1.6142 25.577 (=νd1)  2* −3.0960 0.0263  3* 1.2807 0.2504 1.6607 20.365 (=νd2)  4* 0.9856 0.2942 5(Stop) Infinity 0.0862  6* 3.5403 0.5922 1.5348 55.664 (=νd3)  7* −1.8240 0.4269  8* −1.0952 0.3000 1.6607 20.365 (=νd4)  9* −2.1841 0.0200 10* −1.3182 0.3915 1.5443 55.865 (=νd5) 11* −1.5055 0.0224 12* 1.0369 0.8814 1.5348 55.664 (=νd6) 13* 1.3408 0.4000 14  Infinity 0.2100 1.5168 64.198 15  Infinity 0.5978 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 1 9.924 2 3 −9.769 3 6 2.341 4 8 −3.734 5 10 −73.884 6 12 4.277 Aspheric Surface Data First Surface Second Surface Third Surface Fourth Surface Sixth Surface Seventh Surface k −1.000000E+00 −1.000000E+00   0.000000E+00   0.000000E+00   0.000000E+00 −5.944902E−02 A4    1.852440E−01   3.423947E−01 −3.179384E−01 −7.227058E−01 −5.012847E−02 −1.896248E−01 A6  −1.784482E−01 −4.913421E−01   4.287281E−01   1.728394E+00   2.220611E−01   3.142495E−01 A8    1.774085E−01   6.246944E−01 −1.616703E+00 −5.349135E+00 −2.019633E+00 −1.766685E+00 A10 −1.267891E−01 −5.567401E−01   3.401428E+00   8.518733E+00   8.130063E+00   4.723847E+00 A12   5.883063E−02   3.172701E−01 −4.150488E+00   9.255481E−01 −1.926560E+01 −6.962445E+00 A14 −1.558447E−02 −1.045475E−01   2.769554E+00 −2.157433E+01   2.378882E+01   4.799010E+00 A16   1.753806E−03   1.513234E−02 −7.618726E−01   2.146379E+01 −1.134959E+01 −8.976469E−01 Eighth Surface Ninth Surface Tenth Surface Eleventh Surface Twelfth Surface Thirteenth Surface k   0.000000E+00 −1.632953E+01   0.000000E+00   0.000000E+00 −7.613163E+00 −7.493603E−01 A4  −8.930119E−01 −9.982248E−01   9.002032E−01   8.626765E−02 −1.600928E−01 −2.550694E−01 A6    2.821893E+00   3.253353E+00 −1.200990E+00   3.008498E−02   3.916397E−02   1.080642E−01 A8  −5.625502E+00 −7.292680E+00   7.985914E−01   1.388258E−01   1.297319E−02 −3.886867E−02 A10   9.014237E+00   1.014357E+01 −7.948128E−02 −3.549299E−01 −9.938250E−03   9.427490E−03 A12 −9.048748E+00 −8.281737E+00 −2.554687E−01   3.228468E−01   2.568573E−03 −1.457173E−03 A14   5.258190E+00   3.703395E+00   1.645142E−01 −1.287802E−01 −3.242902E−04   1.285878E−04 A16 −1.352898E+00 −6.998598E−01 −2.860199E−02   1.940597E−02   1.682926E−05 −5.003267E−06

(44) The imaging lens in Example 4 satisfies conditional expressions (1) to (13) as shown in Table 6.

(45) FIG. 8 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 4. As shown in FIG. 8, each aberration is corrected excellently.

Example 5

(46) The basic lens data is shown below in Table 5.

Example 5

(47) TABLE-US-00005 Unit mm f = 2.68 Fno = 1.82 ω(°) = 49.9 ih = 3.26 TTL = 4.79 EPD = 1.48 Surface Data Surface Curvature Surface Refractive Abbe Number Number i Radius r Distance d Index Nd νd (Object) Infinity Infinity  1* −4.6783 0.4204 1.6142 25.577 (=νd1)  2* −2.6427 0.0200  3* 1.3527 0.2641 1.6607 20.365 (=νd2)  4* 1.0274 0.2358 5(Stop) Infinity 0.1152  6* 3.3397 0.6200 1.5348 55.664 (=νd3)  7* −1.9050 0.3908  8* −1.1077 0.3000 1.6607 20.365 (=νd4)  9* −2.2738 0.0300 10* −1.3961 0.3849 1.5443 55.865 (=νd5) 11* −1.5019 0.0200 12* 1.0706 0.8800 1.5348 55.664 (=νd6) 13* 1.3446 0.4000 14  Infinity 0.2100 1.5168 64.198 15  Infinity 0.5963 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 1 9.168 2 3 −9.549 3 6 2.366 4 8 −3.641 5 10 128.910 6 12 4.636 Aspheric Surface Data First Surface Second Surface Third Surface Fourth Surface Sixth Surface Seventh Surface k −1.000000E+00 −1.000000E+00   0.000000E+00   0.000000E+00   0.000000E+00   5.068538E−01 A4    1.763891E−01   3.359570E−01 −2.977206E−01 −7.316771E−01 −2.236595E−02 −1.649370E−01 A6  −1.708080E−01 −4.853198E−01   4.782700E−01   2.349537E+00   1.707712E−02   5.129118E−02 A8    1.668915E−01   6.279517E−01 −1.730987E+00 −1.061686E+01 −6.624418E−01 −1.025262E−01 A10 −1.153057E−01 −5.696096E−01   3.731013E+00   3.413570E+01   2.824043E+00 −8.737474E−01 A12   5.062372E−02   3.275293E−01 −4.837674E+00 −6.841691E+01 −7.273301E+00   3.007893E+00 A14 −1.249050E−02 −1.065001E−01   3.460509E−00   7.536161E+01   8.793461E+00 −4.037129E+00 A16   1.305580E−03   1.484487E−02 −1.024471E+00 −3.344554E+01 −3.799552E+00   2.018630E+00 Eighth Surface Ninth Surface Tenth Surface Eleventh Surface Twelfth Surface Thirteenth Surface k   0.000000E+00 −1.345068E+01   0.000000E+00   0.000000E+00 −8.770243E+00 −7.471994E−01 A4  −8.640003E−01 −9.669597E−01   7.982182E−01   8.476812E−02 −1.364966E−01 −2.523680E−01 A6    2.647624E+00   3.209783E+00 −8.997266E−01   8.003295E−02   1.579885E−02   1.063391E−01 A8  −5.424433E+00 −7.210068E+00   4.479297E−01   1.914663E−01   2.570789E−02 −3.873070E−02 A10   8.665834E+00   9.825922E+00   6.665476E−03 −5.266481E−01 −1.397034E−02   9.574203E−03 A12 −8.094077E+00 −7.776085E+00 −1.314307E−01   4.565622E−01   3.283220E−03 −1.503917E−03 A14   4.172015E+00   3.380741E+00   5.826676E−02 −1.735752E−01 −3.897709E−04   1.339639E−04 A16 −9.417358E−01 −6.264613E−01 −4.313557E−03   2.507036E−02   1.924453E−05 −5.225081E−06

(48) The imaging lens in Example 5 satisfies conditional expressions (1) to (13) as shown in Table 6.

(49) FIG. 10 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 5. As shown in FIG. 10, each aberration is corrected excellently.

(50) As shown below, the imaging lens according to the embodiments of the present invention realizes the low-profileness, the wide field of view and the low F-number.

(51) TABLE-US-00006 ratio of total track length field of view to diagonal length (degree) F-Number Example 1 0.74 100.0 1.82 Example 2 0.74 100.0 1.82 Example 3 0.74 99.8 1.82 Example 4 0.74 100.0 1.82 Example 5 0.73 99.8 1.82

(52) In table 6, values of conditional expressions (1) to (13) related to the Examples 1 to 5 are shown.

(53) TABLE-US-00007 Conditional Expression Example 1 Example 2 Example 3 Example 4 Example 5  (1) t23/t34 0.81 0.82 0.89 0.89 0.90  (2) (Nd − 1)/r1 infinity infinity −0.14 −0.10 −0.10  (3) (1 − Nd)/r2 infinity 0.10 0.24 0.20 0.20  (4) |f2/f| 36.07 3.20 3.60 3.63 3.56  (5) f3/f 0.96 0.87 0.88 0.87 0.88  (6) f4/f −2.01 −1.47 −1.34 −1.39 −1.36  (7) |f5/f| 18.89 25.54 24.80 27.43 48.12  (8) f6/f 1.70 1.52 1.55 1.59 1.73  (9) νd2 20.37 20.37 20.37 20.37 20.37 (10) |νd3 − νd4| 35.30 35.30 35.30 35.30 35.30 (11) TTL/2ih 0.74 0.74 0.74 0.74 0.73 (12) (LIF − L3F)/ 1.00 0.98 0.96 0.95 0.95 (L3R − L5R) (13) EPD/TTL 0.31 0.31 0.31 0.31 0.31

(54) When the imaging lens according to the present invention is adapted to a product with camera function, there is realized contribution to low-profileness, wide field of view and low F-number of the camera, and also high performance thereof.

DESCRIPTION OF REFERENCE NUMERALS

(55) STO: aperture stop, L1: first lens, L2: second lens, L3: third lens, L4: fourth lens, L5: fifth lens, L6: sixth lens, and IMG: image plane