IMAGING LENS

Abstract

There is provided an imaging lens which is low-profile, has a small f-value, and obtains wide field of view which aberrations are properly corrected, in order from an object side to an image side, comprising a first lens having positive refractive power and a convex surface on an object side near an optical axis, a second lens having negative refractive power and a concave surface on the object side near the optical axis, a third lens having positive refractive power and a convex surface on the image side as a double-sided aspheric lens and a fourth lens having negative refractive power and a concave surface on an image side near the optical axis as a double-sided aspheric lens, wherein a conditional expression (1) below is satisfied:

8.5<ih/f<1.0  (1)

where f denotes the focal length of the overall optical system, and ih denotes maximum image height.

Claims

1. An imaging lens, in order from an object side to an image side, comprising a first lens having positive refractive power and a convex surface on an object side near an optical axis, a second lens having negative refractive power and a concave surface on the object side near the optical axis, a third lens having positive refractive power and a convex surface on the image side as a double-sided aspheric lens and a fourth lens having negative refractive power and a concave surface on an image side near the optical axis as a double-sided aspheric lens, wherein a conditional expression (1) below is satisfied:
8.5<ih/f<1.0  (1) where f denotes the focal length of the overall optical system, and ih denotes maximum image height.

2. The imaging lens according to claim 1, a conditional expression (2) below is satisfied:
Fno≦2.4  (2) where Fno denotes a F-number.

3. The imaging lens according to claim 2, a conditional expression (3) below is satisfied:
0.1<|r3/r4|<0.6  (3) where r3 denotes the curvature radius near an optical axis of the object-side surface of the second lens, and r4 denotes the curvature radius near the optical axis of the image-side surface of the second lens.

4. The imaging lens according to claim 3, a conditional expression (4) below is satisfied:
1.2<(r7+r8)/(r7−r8)<2.5  (4) where r7 denotes the curvature radius near an optical axis of the object-side surface of the fourth lens, and r8 denotes the curvature radius near the optical axis of the image-side surface of the fourth lens.

5. The imaging lens according to claim 4, a conditional expression (5) below is satisfied:
0.15<|Sag4/D2|<0.4  (5) where Sag4 denotes an amount of Sag at a maximum effective diameter on the image-side surface of the second lens, and D2 denotes a thickness on the optical axis of the second lens.

6. The imaging lens according to claim 4, a conditional expression (6) below is satisfied:
0.02<|Sag5/D3|<0.13  (6) where Sag5 denotes an amount of Sag at maximum effective diameter on the object-side surface of the third lens, and D3 denotes a thickness on the optical axis of the third lens.

7. The imaging lens according to claim 2, a conditional expression (7) below is satisfied:
0.14<|r1/r2|<0.7  (7) where r1 denotes the curvature radius near an optical axis on the object-side surface of the first lens, and r2 denotes the curvature radius near an optical axis on the image-side surface of the first lens.

8. The imaging lens according to claim 3, a conditional expression (8) below is satisfied:
−7.5<f2/f<−2.0  (8) where f2 denotes a focal length of the second 2.

9. The imaging lens according to claim 2, a conditional expression (9) below is satisfied:
0.3<f3/f<1.2  (9) where f3 denotes a focal length of the third lens.

10. The imaging lens according to claim 2, a conditional expression (10) below is satisfied:
−0.9<f4/f<−0.5  (10) where f4 denotes a focal length of the fourth lens.

11. The imaging lens according to claim 9, a conditional expression (11) below is satisfied:
−1.5<f5/f<−0.5  (11) where r5 denotes the curvature radius near an optical axis of the object-side surface of the third lens.

12. The imaging lens according to claim 2, wherein a refractive power of a third lens is most strong among that of said first lens, said second lens, said third lens and said fourth lens.

13. The imaging lens according to claim 2, a conditional expression (12) below is satisfied:
0.035<T3/D3<0.2  (12) where T3 denotes a distance on the optical axis from the image-side surface of the third lens to the object-side surface of the fourth lens, and D3 denotes a thickness on the optical axis of the third lens.

14. The imaging lens according to claim 2, a conditional expression (13) below is satisfied:
9.0<(T1/f)*100<16.0  (13) where T1 denotes a distance on the optical axis from the image-side surface of the first lens to the object-side surface of the second lens.

15. The imaging lens according to claim 1, a conditional expression (14) below is satisfied:
0.55<TTL/2ih<0.85  (14) where TTL is a total track length.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is a schematic view showing the general configuration of an imaging lens in Example 1 according to an embodiment of the present invention;

[0044] FIG. 2 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 1 according to the embodiment of the present invention;

[0045] FIG. 3 is a schematic view showing the general configuration of an imaging lens in Example 2 according to the embodiment of the present invention;

[0046] FIG. 4 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 2 according to the embodiment of the present invention;

[0047] FIG. 5 is a schematic view showing the general configuration of an imaging lens in Example 3 according to the embodiment of the present invention;

[0048] FIG. 6 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 3 according to the embodiment of the present invention;

[0049] FIG. 7 is a schematic view showing the general configuration of an imaging lens in Example 4 according to the embodiment of the present invention;

[0050] FIG. 8 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 4 according to the embodiment of the present invention;

[0051] FIG. 9 is a view showing an amount of Sag at a maximum effective diameter on the image-side surface of the second lens and an amount of Sag at a maximum effective diameter on the object-side surface of the third lens.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0052] Hereinafter, the preferred embodiment of the present invention will be described in detail referring to the accompanying drawings. FIGS. 1, 3, 5 and 7 are schematic views showing the general configurations of the imaging lenses in Examples 1 to 4 according to this embodiment, 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.

[0053] As shown in FIG. 1, the imaging lens according to this embodiment is an imaging lens comprises, in order from an object side to an image side, a first lens L1 having positive refractive power and a convex surface on the object side near an optical axis X as a double-sided aspheric lens, a second lens L2 having negative refractive power and a concave surface on the object side near the optical axis as a double-sided aspheric lens, a third lens L3 having positive refractive power as a double-sided aspheric lens, and a fourth lens L4 having negative refractive power and a concave surface on an image side near the optical axis as a double-sided aspheric lens. A filter IR such as an IR cut filter is located between the fourth lens L4 and an image plane IMG. The filter IR is omissible. An aperture stop ST is located nearest to the object side so as to be advantageous for low-profileness.

[0054] The imaging lens according to the present embodiment has a structure to make a total track length TTL short by the first lens L1 and the third lens L3 having positive refractive power. The second lens L2 having negative refractive power corrects chromatic aberrations generated at the first lens L1 and enables wide field of view by arranging the concave surface on the object side. The third lens L3 and fourth lens L4 form aspheric surfaces on both sides properly and make it easy to correct off-axial aberrations, decrease astigmatic difference and correct distortion, and control of an incident angle of a main light lay to the image sensor.

[0055] The first lens L1 is meniscus and has a convex surface on an object side and a concave surface on an image side near an optical axis X, and a curvature radius near the optical axis on the object-side surface and the image-side surface is determined so as to be proper relation. The refractive power of the first lens L1 is weaken relative to that of the third lens L3.

[0056] The second lens L2 is meniscus and has a concave surface on an object side and a convex surface on an image side near the optical axis X, and light ray from a wide field of view can be entered because the object-side surface is designed as a concave surface. Change in the amount of Sag is formed as small aspheric shape over maximum effective diameter from near area of the optical axis X, and it becomes advantages in shape to achieve low-profileness. The second lens L2 has simply negative refractive power and a concave surface on the object side near the optical axis X, and may be double-sided lens having a concave surface on the image side near the optical axis X as shown in Embodiment 3 in FIG. 5.

[0057] The third lens L3 is meniscus and has a convex surface on the image side and a concave surface on the object side near the optical axis. The third lens L3 has stronger refractive power than that of the first lens L1, and is large in contribution to low-profileness. Aspheric surfaces on both sides of the third lens L3 properly correct off-axial aberrations. On the object side surface, change of Sag is formed as a small aspheric shape over maximum effective diameter from near area of the optical axis X, there is provided an advantageous shape for low-profileness in addition to the image-side surface of the second lens L2.

[0058] The fourth lens L4 is meniscus and has a concave surface on the image side near the optical axis. Due to aspheric surfaces formed on both sides, correction can be properly made on astigmatic difference and distortion. There is provided aspheric shape on which a pole point is formed on area other than the optical axis X and it becomes easy to control an incident angle of a main light lay to the image plane IMG.

[0059] The imaging lens according to the present embodiments shows preferable effect by satisfying the below conditional expressions (1) to (14).

0.85<ih/f<1.0  (1)

Fno≦2.4  (2)

0.1<|r3/r4|<0.6  (3)

1.2<(r7+r8)/(r7−r8)<2.5  (4)

0.15<|Sag4/D2|<0.4  (5)

0.02<|Sag5/D3|<0.13  (6)

0.14<|r1/r2|<0.7  (7)

−7.5<f2/f<−2.0  (8)

0.3<f3/f<1.2  (9)

−0.9<f4/f<−0.5  (10)

−1.5<f5/f<−0.5  (11)

0.035<T3/D3<0.2  (12)

9.0<(T1/f)*100<16.0  (13)

0.55<TTL/2ih<0.85  (14)

where

[0060] f: focal length of the overall optical system of the imaging lens,

[0061] ih: maximum image height,

[0062] Fno: F-number

[0063] r3: curvature radius near an optical axis of the object-side surface of the second lens L2,

[0064] r4: curvature radius near an optical axis of the image-side surface of the second lens L2,

[0065] r7: curvature radius near an optical axis of the object-side surface of the fourth lens L4,

[0066] r8: curvature radius near an optical axis of the image-side surface of the fourth lens L4,

[0067] Sag4: an amount of Sag at a maximum effective diameter on the image-side surface of the second lens L2,

[0068] D2: a thickness on the optical axis of the second lens L2,

[0069] Sag5: an amount of Sag at a maximum effective diameter on the image-side surface of the third lens L3,

[0070] D3: a thickness on the optical axis of the third lens L3,

[0071] r1: curvature radius near an optical axis of the object-side surface of the first lens L1,

[0072] r2: curvature radius near an optical axis of the image-side surface of the first lens L1,

[0073] f2: focal length of the second lens L2,

[0074] f3: focal length of the third lens L3,

[0075] f4: focal length of the fourth lens L4,

[0076] r5: curvature radius near an optical axis of the object-side surface of the third lens L3,

[0077] T1: a distance on the optical axis X from the image-side surface of the first lens L1 to the object-side surface of the second lens L2,

[0078] T3: a distance on the optical axis X from the image-side surface of the third lens L3 to the object-side surface of the fourth lens L4, and

[0079] TTL: total track length.

[0080] Furthermore, the imaging lens according to the present embodiments shows preferable effect by satisfying the below conditional expressions (1a) to (14a).

0.85<ih/f<0.95  (1a)

Fno≦2.2  (2a)

0.2<|r3/r4|<0.5  (3a)

1.2<(r7+r8)/(r7−r8)<2.0  (4a)

0.15<|Sag4/D2|<0.35  (5a)

0.03<|Sag5/D3|<0.10  (6a)

0.14<|r1/r2|<0.6  (7a)

−7.5<f2/f<−3.0  (8a)

0.45<f3/f<1.0  (9a)

−0.8<f4/f<−0.55  (10a)

−1.5<f5/f<−0.6  (11a)

0.04<T3/D3<0.15  (12a)

9.0<(T1/f)*100<14.0  (13a)

0.6<TTL/2ih<0.8  (14a)

[0081] The signs in the above conditional expressions have the same meanings as those in the paragraph before the preceding paragraph.

[0082] Additionally, the imaging lens according to the present embodiments shows more preferable effect by satisfying the below conditional expressions (1b) to (14b).

0.85<ih/f≦0.92  (1b)

Fno≦2.1  (2b)

0.22≦|r3/r4|≦0.38  (3b)

1.6≦(r7+r8)/(r7−r8)≦2.0  (4b)

0.20≦|Sag4/D2|≦0.31  (5b)

0.05≦|Sag5/D3|≦0.08  (6b)

0.15<|r1/r2|≦0.37  (7b)

−6.16≦f2/f≦−2.97  (8b)

0.56≦f3/f<1.0  (9b)

−0.77≦f4/f<−0.6  (10b)

−1.45≦f5/f≦−0.77  (11b)

0.04<T3/D3<0.1  (12b)

9.0<(T1/f)*100≦13.3  (13b)

0.65<TTL/2ih<0.8  (14b)

[0083] The signs in the above conditional expressions have the same meanings as those in the paragraph before the preceding paragraph.

[0084] In this embodiment, all the lens surfaces are aspheric. The aspheric shapes of these lens surfaces are expressed by Equation 1, where Z denotes an axis in the optical axis direction, H denotes a height perpendicular to the optical axis, k denotes a conic constant, and A4, A6, A8, A10, A12, A14, and A16 denote aspheric surface coefficients.

[00001]$\begin{array}{cc}Z=\frac{\frac{H^2}{R}}{1+\sqrt{1-\left(k+1\right).Math.\frac{H^2}{R^2}}}+A_4.Math.H^4+A_6.Math.H^6+A_8.Math.H^8+A_{10}.Math.H^{10}+A_{12}.Math.H^{12}+A_{14}.Math.H^{14}+A_{16}.Math.H^{16}& \mathrm{Equation}.Math..Math.1\end{array}$

[0085] 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, ω denotes a half field of view, ih denotes a maximum image height. Additionally, i denotes surface number counted from the object side, r denotes a curvature radius, d denotes the distance of lenses on 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

[0086]

TABLE-US-00001 TABLE 1 Unit [mm] f = 2.50 Fno = 2.1 ω (°) = 42 ih = 2.29 Surface Data Surface Curvature Surface Abbe Number i Radius r Distance d Refractive Number (Object) Infinity Infinity Index Nd νd  1 (Stop) Infinity −0.150  2* 1.104 (=r1) 0.428 1.5443 55.86  3* 3.005 (=r2) 0.332 (=T1)  4* −7.371 (=r3)  0.200 (=D2) 1.6503 21.54  5* −28.109 (=r4)  0.191 (=T2)  6* −1.931 (=r5)  0.600 (=D3) 1.5348 55.66  7* −0.697 (=r6)  0.036 (=T3)  8* 2.361 (=r7) 0.447 1.5348 55.66  9* 0.660 (=r8) 0.232 10 Infinity 0.210 1.5168 64.20 11 Infinity 0.614 Image Infinity Plane Constituent Lens Data Lens Start Surface Focal Length 1 2 2.97 2 4 −15.42 3 6 1.74 4 8 −1.89 Aspheric Surface data Second Third Fourth Fifth Surface Surface Surface Surface k 0.000E+00 0.000E+00 0.000E+00 −9.778E+00 A4 2.672E−02 −4.268E−03 −3.875E−01 −2.667E−02 A6 −1.127E−01 −4.674E−01 −1.485E+00 −1.270E+00 A8 5.258E−01 1.381E+00 3.420E+00 2.595E+00 A10 −8.809E−01 −3.296E+00 −6.712E+00 −2.805E+00 A12 0.000E+00 5.946E−01 7.042E+00 1.267E+00 A14 0.000E+00 0.000E+00 0.000E+00 2.439E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Sixth Seventh Eighth Ninth Surface Surface Surface Surface k 0.000E+00 −4.016E+00 0.000E+00 −5.205E+00 A4 5.595E−01 −2.912E−01 −4.937E−01 −2.377E−01 A6 −8.030E−01 7.065E−01 4.315E−01 2.100E−01 A8 6.128E−01 −9.996E−01 −3.890E−01 −1.570E−01 A10 −1.774E−01 1.318E+00 2.940E−01 7.757E−02 A12 −7.912E−03 −1.089E+00 −1.318E−01 −2.371E−02 A14 0.000E+00 4.514E−01 3.040E−02 3.981E−03 A16 0.000E+00 −7.367E−02 −2.822E−03 −2.761E−04

[0087] The imaging lens in Example 1 satisfies all of conditional expressions (1) to (14) as shown in Table 5.

[0088] 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 and distortion diagram show the amount of aberration at d-ray. The astigmatism diagram shows sagittal image surface S and the amount of aberration on tangential image surface T. As shown in FIG. 2, each aberration is corrected properly.

[0089] Furthermore, the total track length TTL is less than 3.3 mm, ratio of total track length to diagonal length is 0.7, and there is realized photographing having brightness of F2.1, field of view of 2ω and 80 degrees or more, while maintaining being compact and low-profileness.

Example 2

[0090]

TABLE-US-00002 TABLE 2 Unit [mm] f = 2.49 Fno = 2.1 ω (°) = 42 ih = 2.29 Surface Data Surface Curvature Surface Abbe Number i Radius r Distance d Refractive Number (Object) Infinity Infinity Index Nd νd  1 (Stop) Infinity −0.113  2*  1.198 (=r1) 0.489 1.5443 55.86  3*  5.731 (=r2) 0.279 (=T1)  4* −2.910 (=r3) 0.220 (=D2) 1.6503 21.54  5* −7.565 (=r4) 0.140 (=T2)  6* −1.977 (=r5) 0.569 (=D3) 1.5348 55.66  7* −0.693 (=r6) 0.030 (=T3)  8*  1.977 (=r7) 0.440 1.5348 55.66  9*  0.625 (=r8) 0.248 10 Infinity 0.210 1.5168 64.20 11 Infinity 0.664 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 2 2.68 2 4 −7.41 3 6 1.73 4 8 −1.92 Aspheric Surface data Second Third Fourth Fifth Surface Surface Surface Surface k 0.000E+00 0.000E+00 0.000E+00 −9.778E+00 A4 1.539E−02 −2.500E−01 −6.829E−01 5.805E−02 A6 −4.730E−01 9.864E−03 −4.013E−01 −2.370E+00 A8 1.627E+00 −2.204E+00 −3.979E+00 7.204E+00 A10 −3.099E+00 2.885E+00 2.096E+01 −1.272E+01 A12 0.000E+00 −1.261E+00 −2.001E+01 1.911E+01 A14 0.000E+00 0.000E+00 0.000E+00 −1.214E+01 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Sixth Seventh Eighth Ninth Surface Surface Surface Surface k 0.000E+00 −4.649E+00 0.000E+00 −5.140E+00 A4 9.336E−01 −3.942E−01 −6.217E−01 −2.720E−01 A6 −2.340E+00 1.337E+00 5.986E−01 2.579E−01 A8 3.477E+00 −2.342E+00 −5.156E−01 −1.953E−01 A10 −2.589E+00 3.060E+00 3.681E−01 9.881E−02 A12 7.206E−01 −2.473E+00 −1.661E−01 −3.148E−02 A14 0.000E+00 1.041E+00 3.987E−02 5.587E−03 A16 0.000E+00 −1.758E−01 −3.905E−03 −4.136E−04

[0091] The imaging lens in Example 2 satisfies all of conditional expressions (1) to (14) as shown in Table 5.

[0092] FIG. 4 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 2. 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 and distortion diagram show the amount of aberration at d-ray. The astigmatism diagram shows sagittal image surface S and the amount of aberration on tangential image surface T. As shown in FIG. 4, each aberration is corrected properly.

[0093] Furthermore, the total track length TTL is less than 3.3 mm, ratio of total track length to diagonal length is 0.7, and there is realized photographing having brightness of F2.1, field of view of 2ω and 80 degrees or more, while maintaining being compact and low-profileness.

Example 3

[0094]

TABLE-US-00003 TABLE 3 Unit [mm] f = 2.49 Fno = 2.1 ω (°) = 42 ih = 2.30 Surface Data Surface Curvature Surface Abbe Number i Radius r Distance d Refractive Number (Object) Infinity Infinity Index Nd νd  1 (Stop) Infinity −0.142  2* 1.176 (=r1) 0.428 1.5443 55.86  3* 3.913 (=r2) 0.312 (=T1)  4* −5.096 (=r3)  0.221 (=D2) 1.6503 21.54  5* 22.954 (=r4)  0.180 (=T2)  6* −3.620 (=r5)  0.645 (=D3) 1.5348 55.66  7* −0.655 (=r6)  0.052 (=T3)  8* 2.191 (=r7) 0.367 1.5348 55.66  9* 0.570 (=r8) 0.313 10 Infinity 0.210 1.5168 64.20 11 Infinity 0.590 Image Plane Infinity Constituent Lens Data Lens Start Surface Focal Length 1 2 2.93 2 4 −6.39 3 6 1.39 4 8 −1.56 Aspheric Surface data Second Third Fourth Fifth Surface Surface Surface Surface k 0.000E+00 0.000E+00 0.000E+00 6.357E+01 A4 3.844E−03 −9.705E−02 −5.671E−01 −2.374E−01 A6 −2.010E−01 −4.258E−01 −1.065E+00 −6.236E−01 A8 8.596E−01 4.119E−01 3.700E+00 1.897E+00 A10 −1.904E+00 −1.982E+00 −9.742E+00 −2.771E+00 A12 0.000E+00 5.995E−01 1.279E+01 3.163E+00 A14 0.000E+00 0.000E+00 0.000E+00 −3.500E−01 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Sixth Seventh Eighth Ninth Surface Surface Surface Surface k 0.000E+00 −4.189E+00 0.000E+00 −4.749E+00 A4 3.707E−01 −2.664E−01 −5.021E−01 −2.388E−01 A6 −5.897E−01 6.425E−01 4.282E−01 2.114E−01 A8 5.894E−01 −9.472E−01 −3.894E−01 −1.569E−01 A10 −2.889E−01 1.320E+00 2.952E−01 7.762E−02 A12 4.576E−02 −1.098E+00 −1.319E−01 −2.385E−02 A14 0.000E+00 4.487E−01 3.033E−02 4.043E−03 A16 0.000E+00 −7.126E−02 −2.807E−03 −2.842E−04

[0095] The imaging lens in Example 3 satisfies all of conditional expressions (1) to (14) as shown in Table 5.

[0096] FIG. 6 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 3.

[0097] 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 and distortion diagram show the amount of aberration at d-ray. The astigmatism diagram shows sagittal image surface S and the amount of aberration on tangential image surface T. As shown in FIG. 6, each aberration is corrected properly.

[0098] Furthermore, the total track length TTL is less than 3.3 mm, ratio of total track length to diagonal length is 0.71, and there is realized photographing having brightness of F2.1, field of view of 2ω and 80 degrees or more, while maintaining being compact and low-profileness.

Example 4

[0099]

TABLE-US-00004 TABLE 4 Unit [mm] f = 2.50 Fno = 2.1 ω (°) = 42 ih = 2.30 Surface Data Surface Curvature Surface Abbe Number i Radius r Distance d Refractive Number (Object) Infinity Infinity Index Nd νd  1 (Stop) Infinity −0.126  2* 1.149 (=r1) 0.429 1.5443 55.86  3* 3.845 (=r2) 0.312 (=T1)  4* −4.009 (=r3)  0.205 (=D2) 1.6503 21.54  5* −13.683 (=r4)  0.169 (=T2)  6* −2.895 (=r5)  0.661 (=D3) 1.5348 55.66  7* −0.730 (=r6)  0.044 (=T3)  8* 2.508 (=r7) 0.435 1.5348 55.66  9* 0.654 (=r8) 0.271 10 Infinity 0.210 1.5168 64.20 11 Infinity 0.584 Image Infinity Plane Constituent Lens Data Lens Start Surface Focal Length 1 2 2.85 2 4 −8.79 3 6 1.65 4 8 −1.80 Aspheric Surface data Second Third Fourth Fifth Surface Surface Surface Surface k 0.000E+00 0.000E+00 0.000E+00 4.511E+01 A4 1.097E−02 −7.734E−02 −5.250E−01 −1.880E−01 A6 −2.031E−01 −4.961E−01 −1.055E+00 −6.153E−01 A8 8.869E−01 6.684E−01 3.316E+00 1.779E+00 A10 −1.961E+00 −1.875E+00 −9.032E+00 −2.449E+00 A12 0.000E+00 −3.164E+00 1.268E+01 3.517E+00 A14 0.000E+00 5.540E+00 0.000E+00 −7.234E−01 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Sixth Seventh Eighth Ninth Surface Surface Surface Surface k 0.000E+00 −3.913E+00 0.000E+00 −4.785E+00 A4 3.521E−01 −2.534E−01 −5.003E−01 −2.374E−01 A6 −5.472E−01 5.865E−01 4.381E−01 2.116E−01 A8 6.198E−01 −8.981E−01 −3.908E−01 −1.574E−01 A10 −3.406E−01 1.319E+00 2.952E−01 7.790E−02 A12 4.210E−02 −1.106E+00 −1.321E−01 −2.393E−02 A14 2.018E−03 4.453E−01 3.042E−02 4.046E−03 A16 0.000E+00 −6.954E−02 −2.829E−03 −2.831E−04

[0100] The imaging lens in Example 4 satisfies all of conditional expressions (1) to (14) as shown in Table 5.

[0101] FIG. 8 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 3.

[0102] 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 and distortion diagram show the amount of aberration at d-ray. The astigmatism diagram shows sagittal image surface S and the amount of aberration on tangential image surface T. As shown in FIG. 8, each aberration is corrected properly.

[0103] Furthermore, the total track length TTL is less than 3.3 mm, ratio of total track length to diagonal length is 0.71, and there is realized photographing having brightness of F2.1, field of view of 2ω and 80 degrees or more, while maintaining being compact and low-profileness.

[0104] Each parameter of Examples 1 to 4, and value of the conditional expressions (1) to (14) are shown in Table 5.

Example 5

[0105]

TABLE-US-00005 TABLE 5 Exam- Exam- Exam- Exam- Parameters ple 1 ple 2 ple 3 ple 4 f 2.50 2.49 2.49 2.50 ih 2.29 2.29 2.30 2.30 Fno 2.1 2.1 2.1 2.1 r3 −7.371 −2.910 −5.096 −4.009 r4 −28.109 −7.565 22.954 −13.683 r7 2.361 1.977 2.191 2.508 r8 0.660 0.625 0.570 0.654 Sag4 −0.06 −0.06 −0.05 −0.06 D2 0.200 0.220 0.221 0.205 Sag5 −0.10 −0.06 −0.02 −0.05 D3 0.600 0.569 0.645 0.661 r1 1.104 1.198 1.176 1.149 r2 3.005 5.731 3.913 3.845 f2 −15.42 −7.41 −6.39 −8.79 f3 1.74 1.73 1.39 1.65 f4 −1.89 −1.92 −1.56 −1.80 r5 −1.931 −1.977 −3.620 −2.895 T1 0.332 0.279 0.312 0.312 T3 0.036 0.030 0.052 0.044 TTL 3.219 3.218 3.247 3.248 (1) 0.85 < ih/f < 1.0 0.91 0.92 0.92 0.92 (2) Fno ≦ 2.4 2.1 2.1 2.1 2.1 (3) 0.1 < |r3/r4| < 0.6 0.26 0.38 0.22 0.29 (4) 1.2 < (r7 + r8)/(r7 − r8) < 2.5 1.78 1.92 1.70 1.71 (5) 0.15 < |Sag4/D2| < 0.4 0.31 0.25 0.20 0.27 (6) 0.02 < |Sag5/D3| < 0.13 0.17 0.11 0.03 0.07 (7) 0.14 < |r1/r2| < 0.7 0.37 0.21 0.30 0.30 (8) −7.5 < f2/f < −2.0 −6.16 −2.97 −2.56 −3.51 (9) 0.3 < f3/f < 1.2 0.70 0.69 0.56 0.66 (10)−0.9 < f4/f < −0.5 −0.75 −0.77 −0.63 −0.72 (11)−1.5 < r5/f < −0.5 −0.77 −0.79 −1.45 −1.16 (12)0.035 < T3/D3 < 0.2 0.06 0.05 0.08 0.07 (13)9.0 < (T1/f)*100 < 16.0 13.3 11.2 12.5 12.5 (14)0.55 < TTL/2ih < 0.85 0.70 0.70 0.71 0.71

[0106] As explained so far, if the imaging lens according to each embodiment of the present invention is applied to a mobile terminal such as a mobile phone, smartphone, or PDA (Personal Digital Assistant), or an imaging device mounted in a game console, the camera having high-performance and contributing to low-profileness of the device can be obtained.

[0107] According to the present invention, there is obtained the bright imaging lens for properly correcting aberrations, being compact, and having wide field of view enabling low-profileness.