Seven-piece imaging lens

Abstract

A seven-element imaging lens comprises, from the object side to the image side, a front lens group, an aperture, and a rear lens group. The front lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side. The front lens group as a whole has negative refractive power. The image-side surface of the first lens is concave, the image-side surface of the second lens is concave, and the image-side surface of the third lens is concave. The rear lens group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side to the image side. The rear lens group as a whole has positive refractive power. The object-side and image-side surfaces of the fifth lens and the seventh lens are both convex.

Description

Technical Field ,

[0005] , , , , ,

[0006] , , , , ,

[0007] ,

[0004] ,

[0001] The present invention relates to an optical lens, particularly to a seven-piece imaging lens. Prior Art

[0002] Optical lenses are widely used by people. How to balance the imaging quality under the conditions of large aperture, large viewing angle, and high relative illuminance is indeed worthy of consideration by those in this field. Summary of the Invention

[0003] The main object of the present invention is to provide a seven-piece imaging lens that can balance the imaging quality under the conditions of large aperture, large viewing angle, and high relative illuminance.

[0004] To achieve the above and other objects, the present invention provides a seven-piece imaging lens, which sequentially includes a front lens group, an aperture, and a rear lens group from the object side to the image side. The front lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side. The front lens group as a whole has a negative refractive power. The image side surface of the first lens is concave, the image side surface of the second lens is concave, and the image side surface of the third lens is concave. The rear lens group includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side to the image side. The rear lens group as a whole has a positive refractive power. The object side surface and the image side surface of the fifth lens are both convex, and the object side surface and the image side surface of the seventh lens are both convex. Through the above-mentioned refractive power configuration and surface type matching, the lens of the present invention can balance the imaging quality under the conditions of large aperture, large viewing angle, and high relative illuminance.

[0005] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 1.6 < (2 * SD2) / R2 < 1.85; where SD2 is the height in the direction perpendicular to the optical axis at the maximum viewing angle on the image side surface of the first lens, and R2 is the radius of curvature of the image side surface of the first lens; thereby, the viewing angle can be increased.

[0006] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 1.3 < SD4 / SAG4 < 1.6; where SD4 is the height in the direction perpendicular to the optical axis at the maximum viewing angle on the image side surface of the second lens, and SAG4 is the distance in the direction parallel to the optical axis between the intersection point of the image side surface of the second lens on the optical axis and the maximum viewing angle of the image side surface of the second lens; thereby, the system distortion can be corrected.

[0007] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 0.3 < F / F4 < 0.6, where F is the system focal length of the seven-piece imaging lens and F4 is the focal length of the fourth lens; thereby, the influence of temperature on the system can be corrected.

[0008] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 3.5 < (T9 / MNG5) * (MNG6 / T11) < 6.5, where MNG5 is the thickness at the maximum viewing angle of the fifth lens, MNG6 is the thickness at the maximum viewing angle of the sixth lens, T9 is the thickness of the fifth lens on the optical axis, and T11 is the thickness of the sixth lens on the optical axis; by the surface type matching of the fifth and sixth lenses, the system astigmatism can be corrected.

[0009] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 10 < T7 / (T6 + T8) < 22, where T7 is the thickness of the fourth lens on the optical axis, T6 is the gap on the optical axis between the third and fourth lenses, and T8 is the gap on the optical axis between the fourth and fifth lenses; thereby, the system aberration can be corrected.

[0010] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 2 < MNG6 / T11 < 4.5, where MNG6 is the thickness at the maximum viewing angle of the sixth lens and T11 is the thickness of the sixth lens on the optical axis; thereby, the spherical aberration of the rear lens group can be balanced and the imaging quality can be improved.

[0011] In the seven-piece imaging lens as described above, the following relational expression can also be satisfied: 1 mm < |SAG14| < 2 mm, where SAG14 is the distance in the direction parallel to the optical axis between the intersection of the image side surface of the seventh lens on the optical axis and the maximum viewing angle of the image side surface of the seventh lens; thereby, the problem of stray light can be improved. Brief Description of the Drawings

[0012] Figure 1 is a schematic diagram of the first embodiment of the present invention.

[0013] <mino> Figure 2 is the field curvature diagram of the first embodiment of the present invention.

[0014] Figure 3 is the distortion diagram of the first embodiment of the present invention.

[0015] Figure 4 is a schematic diagram of the second embodiment of the present invention.

[0016] Figure 5 is a field curve diagram of the second embodiment of the present invention.

[0017] Figure 6 is a distortion diagram of the second embodiment of the present invention.

[0018] Figure 7 is a schematic diagram of the third embodiment of the present invention.

[0019] Figure 8 is a field curve diagram of the third embodiment of the present invention.

[0020] Figure 9 is a distortion diagram of the third embodiment of the present invention.

[0021] Figure 10 is a schematic diagram of the fourth embodiment of the present invention.

[0022] Figure 11 is a field curve diagram of the fourth embodiment of the present invention.

[0023] Figure 12 is a distortion diagram of the fourth embodiment of the present invention.

[0024] Figure 13 is a schematic diagram of the fifth embodiment of the present invention.

[0025] Figure 14 is a field curve diagram of the fifth embodiment of the present invention.

[0026] Figure 15 is a distortion diagram of the fifth embodiment of the present invention. Implementation

[0027] Please refer to Figure 1, which illustrates the first embodiment of the present invention. The seven-element imaging lens, along the optical axis L from object side A to image side B, sequentially includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, an aperture ST, a fifth lens 50, a sixth lens 60, and a seventh lens 70. A CCD, CMOS, or other photosensitive element (not shown) is located at image side B. A filter and / or protective glass, or other flat lens 80, may be provided between the photosensitive element and the seventh lens 70. The number of flat lens 80 can be increased, decreased, or omitted as needed. The first lens 10, second lens 20, third lens 30, and fourth lens 40 constitute a front lens group G1, which has negative refractive power. The fifth lens 50, sixth lens 60, and seventh lens 70 constitute a rear lens group G2, which has positive refractive power.

[0028] First, it should be stated that in this article, when the center of a surface is closer to the image side than the surface itself, the radius of curvature of the surface is positive; conversely, when the center of a surface is closer to the object side than the surface itself, the radius of curvature of the surface is negative. Unless otherwise stated, the concave and convex shapes and radii of curvature of the "object side" and "image side" refer to the surface shape and radius of curvature of the surface at the optical axis L.

[0029] In the first embodiment of the present invention, the first lens 10 has negative refractive power, its object side is convex and its image side is concave, and its surface shape helps to increase the system's viewing angle.

[0030] The second lens 20 has negative refractive power, with its object side being convex and its image side being concave.

[0031] The third lens 30 has negative refractive power, and both its object side and image side are concave. Its combination with the second lens 20 can correct distortion.

[0032] The fourth lens 40 has positive refractive power, with a convex object side and a concave image side, which can correct the effect of temperature on the system.

[0033] The fifth lens 50 has positive refractive power, and both its object side and image side are convex.

[0034] The sixth lens 60 has negative refractive power, its object side is concave and its image side is convex, and its combination with the fifth lens 50 can correct astigmatism.

[0035] The seventh lens 70 has positive refractive power, and both its object side and image side are convex, which can correct stray light in the system.

[0036] In this embodiment, the first and fourth lenses are made of glass, while the second, third, fifth, sixth, and seventh lenses are made of plastic. Furthermore, the object-side and image-side surfaces of the second, third, fifth, sixth, and seventh lenses are all aspherical.

[0037] The design parameters of the seven-element imaging lens in this embodiment are shown in Table 1 below. It should be noted that the distance value corresponding to the object side represents the thickness of the lens on the optical axis L (on-axis thickness), and the distance value corresponding to the image side represents the distance between the lens and the next lens or the next aperture ST on the optical axis L (on-axis spacing).

[0038] Table 1 First Embodiment The system has a focal length of 2.37 mm, a length of 25.00 mm, and a maximum angle of view of 170.2°. The aperture is f / 1.8, the maximum image height is 4.2 mm, and the entrance pupil diameter is 1.31 mm. lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (V / Vd) Focal length (mm) First lens Side view 1 30.12 0.63 1.71 53.83 -12.48 Like the side view 2 6.83 0.95 Second lens 3rd side of the object 14.88 1.27 1.54 55.71 -7.26 Like the side view 4 3.00 3.42 Third lens 5 sides of the object -8.16 1.63 1.54 55.71 -5.72 Like the side view 6 5.27 0.06 Fourth lens 7 sides of the object 4.60 4.24 2.00 25.43 5.11 Like the side view 8 23.17 0.33 aperture ∞ -0.29 Fifth lens 9 sides of the object 3.87 2.52 1.54 55.71 4.13 Like the side view 10 -4.00 0.21 Sixth lens 11 Side of the object -2.12 0.85 1.66 20.38 -3.64 Like the side view 12 -19.16 0.17 Seventh Lens 13 sides of the object 3.11 5.38 1.54 55.71 4.57 Like the side view 14 -4.59 0.99 Flat lenses 15 on the side of the object ∞ 0.70 Like the side view 16 ∞ 1.97

[0039] The surface shape of an aspherical surface satisfies the following aspherical formula:

[0040] Where c = 1 / r, r is the surface radius of curvature, h is the height of the light ray on this surface, k is the conic coefficient, B is the fourth-order coefficient, C is the sixth-order coefficient, D is the eighth-order coefficient, E is the tenth-order coefficient, F is the twelfth-order coefficient, G is the fourteenth-order coefficient, and H is the sixteenth-order coefficient. The parameters of each aspherical surface in this embodiment are shown in Table 2 below:

[0041] Table 2 3rd side of the object Like the side view 4 5 sides of the object Like the side view 6 k 0.00E+00 -2.55E+00 2.70E+00 5.76E-02 B 2.09E-03 8.66E-03 -4.95E-03 -3.18E-03 C -7.95E-05 -3.95E-04 1.07E-03 9.72E-04 D 2.34E-06 1.05E-05 -7.79E-05 -4.89E-05 E -3.22E-08 -1.39E-07 3.01E-06 6.93E-07 F 0.00E+00 0.00E+00 -4.15E-08 0.00E+00 G 0.00E+00 0.00E+00 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 9 sides of the object Like the side view 10 11 Side of the object Like the side view 12 k 5.85E-01 -2.26E+01 -5.84E+00 0.00E+00 B -6.80E-03 -4.17E-02 -1.06E-02 1.32E-02 C -1.84E-03 9.46E-03 -2.28E-03 3.22E-04 D 1.78E-03 -3.36E-03 1.62E-03 -4.58E-04 E -9.75E-04 8.26E-04 -7.42E-04 6.63E-05 F 2.55E-04 -1.06E-04 1.74E-04 -1.92E-06 G -2.93E-05 5.58E-06 -1.57E-05 -1.45E-07 H 0.00E+00 -2.11E-07 3.95E-08 0.00E+00 13 sides of the object Like the side view 14 k -1.05E+01 0.00E+00 B 3.51E-03 2.78E-03 C -3.50E-04 -2.25E-05 D 1.87E-05 1.08E-05 E -6.21E-08 -8.99E-07 F -1.65E-08 3.26E-08 G 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00

[0042] Based on Tables 1 and 2, the numerical values ​​of the relational formulas in Table 3 below can be obtained:

[0043] Table 3 relational expression numerical values (2*SD2) / R2 1.61 SD4 / SAG4 1.47 F / F4 0.46 (T9 / MNG5)*(MNG6 / T11) 3.88 T7 / (T6+T8) 10.86 MNG6 / T11 2.13 |SAG14| 1.52 mm

[0044] In this way, through the combination of lenses, the seven-element imaging lens of this embodiment can achieve good image quality. Its field curvature and distortion diagrams can be seen in Figures 2 and 3, clearly demonstrating that this embodiment has good imaging effect.

[0045] Please refer to Figure 4, which illustrates the second embodiment of this invention. Its lens configuration is largely the same as that of the first embodiment. The design parameters of the seven-element image-taking lens in this embodiment are shown in Table 4 below.

[0046] Table 4 Second Embodiment The system has a focal length of 2.30 mm, a length of 25.03 mm, and a maximum angle of view of 168°. The aperture is f / 1.8, the maximum image height is 4.23 mm, and the entrance pupil diameter is 1.28 mm. lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (V / Vd) Focal length (mm) First lens Side view 1 20.93 0.52 1.71 53.83 -13.17 Like the side view 2 6.43 1.71 Second lens 3rd side of the object 9.21 1.28 1.54 55.71 -7.23 Like the side view 4 2.60 3.03 Third lens 5 sides of the object -10.20 1.42 1.54 55.71 -6.30 Like the side view 6 5.31 0.06 Fourth lens 7 sides of the object 4.64 3.87 1.92 20.88 5.95 Like the side view 8 16.96 0.29 aperture ∞ -0.23 Fifth lens 9 sides of the object 3.94 2.28 1.54 55.71 4.10 Like the side view 10 -3.98 0.23 Sixth lens 11 Side of the object -1.82 0.89 1.66 20.38 -3.55 Like the side view 12 -9.46 0.15 Seventh Lens 13 sides of the object 2.68 5.69 1.54 55.71 4.35 Like the side view 14 -4.70 1.00 Flat lenses 15 on the side of the object ∞ 0.70 Like the side view 16 ∞ 2.152

[0047] The parameters of each aspherical surface in this embodiment are shown in Table 5 below:

[0048] Table 5 3rd side of the object Like the side view 4 5 sides of the object Like the side view 6 k 0.00E+00 -2.26E+00 5.47E+00 1.55E+00 B 1.47E-04 7.67E-03 -5.17E-03 -5.00E-03 C -4.75E-05 -6.91E-04 1.10E-03 1.04E-03 D 2.07E-06 2.29E-05 -7.08E-05 -5.10E-05 E -3.32E-08 2.83E-07 2.00E-06 -1.49E-06 F 0.00E+00 0.00E+00 0.00E+00 0.00E+00 G 0.00E+00 0.00E+00 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Side of the object 9 Like the side view 10 Side view of the object 11 Like the side view 12 k 9.27E-01 -2.27E+01 -4.95E+00 0.00E+00 B -8.07E-03 -3.93E-02 -9.44E-03 1.09E-02 C -1.58E-03 8.59E-03 -2.25E-03 7.99E-04 D 1.60E-03 -3.35E-03 1.50E-03 -4.26E-04 E -9.03E-04 7.48E-04 -6.74E-04 5.44E-05 F 2.28E-04 -7.97E-05 1.44E-04 -2.17E-06 G -2.61E-05 3.23E-06 -9.74E-06 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Side of the object 13 Like the side view 14 k -8.61E+00 0.00E+00 B 3.49E-03 4.08E-03 C -3.00E-04 -8.65E-05 D 1.36E-05 1.39E-05 E -1.12E-07 -8.88E-07 F -8.64E-09 2.34E-08 G 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00

[0049] Based on Tables 4 and 5, the numerical values ​​of the relational formulas in Table 6 below can be obtained:

[0050] Table 6 relational expression numerical values (2*SD2) / R2 1.72 SD4 / SAG4 1.55 F / F4 0.39 (T9 / MNG5)*(MNG6 / T11) 4.26 T7 / (T6+T8) 11.13 MNG6 / T11 2.06 |SAG14| 1.30 mm

[0051] In this way, through the combination of lenses, the seven-element imaging lens of this embodiment can achieve good image quality. Its field curvature and distortion diagrams can be seen in Figures 5 and 6, clearly demonstrating that this embodiment has good imaging effect.

[0052] Please refer to Figure 7, which illustrates the third embodiment of this invention. Its lens configuration is largely the same as that of the first embodiment. The design parameters of the seven-element image-taking lens in this embodiment are shown in Table 7 below:

[0053] Table 7 Third Embodiment The system has a focal length of 2.31 mm, a length of 25.01 mm, and a maximum angle of view of 165.4°. The aperture is f / 1.8, the maximum image height is 4.10 mm, and the entrance pupil diameter is 1.29 mm. lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (V / Vd) Focal length (mm) First lens Side view 1 16.51 0.52 1.83 42.73 -12.24 Like the side view 2 6.24 1.51 Second lens 3rd side of the object 5.75 1.06 1.54 55.71 -7.87 Like the side view 4 2.28 3.27 Third lens 5 sides of the object -5.95 1.59 1.54 55.71 -5.88 Like the side view 6 7.37 0.09 Fourth lens 7 sides of the object 4.94 4.38 2.00 25.43 5.51 Like the side view 8 24.58 0.19 aperture ∞ -0.15 Fifth lens 9 sides of the object 3.69 2.59 1.54 56.12 3.70 Like the side view 10 -3.35 0.26 Sixth lens 11 Side of the object -1.69 1.02 1.66 20.38 -3.14 Like the side view 12 -10.88 0.09 Seventh Lens 13 sides of the object 2.83 5.41 1.54 55.71 4.40 Like the side view 14 -4.77 1.00 Flat lenses 15 on the side of the object ∞ 0.70 Like the side view 16 ∞ 1.50

[0054] The parameters of each aspherical surface in this embodiment are shown in Table 8 below:

[0055] Table 8 3rd side of the object Like the side view 4 5 sides of the object Like the side view 6 k 0.00E+00 -2.17E+00 1.32E+00 2.11E+00 B -3.75E-03 6.70E-03 -2.78E-03 -2.90E-03 C 1.08E-04 -9.90E-04 1.06E-03 1.07E-03 D -1.73E-06 8.23E-05 -8.16E-05 -1.11E-04 E -1.35E-08 -2.14E-06 2.71E-06 4.44E-06 F 0.00E+00 0.00E+00 0.00E+00 0.00E+00 G 0.00E+00 0.00E+00 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 9 sides of the object Like the side view 10 11 Side of the object Like the side view 12 k 1.44E+00 -1.64E+01 -4.29E+00 0.00E+00 B -5.17E-03 -3.49E-02 -5.32E-03 1.07E-02 C -6.37E-03 9.58E-03 -2.73E-03 8.31E-04 D 3.48E-03 -3.64E-03 1.51E-03 -4.17E-04 E -1.13E-03 7.25E-04 -6.60E-04 5.79E-05 F 1.54E-04 -6.97E-05 1.39E-04 -2.51E-06 G -8.91E-06 2.86E-06 -9.54E-06 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 13 sides of the object Like the side view 14 k -1.04E+01 0.00E+00 B 3.43E-03 4.62E-03 C -3.05E-04 -2.00E-04 D 4.36E-06 2.34E-05 E 1.14E-06 -1.65E-06 F -4.55E-08 4.79E-08 G 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00

[0056] Based on Tables 7 and 8, the numerical values ​​of the relational formulas in Table 9 below can be obtained:

[0057] Table 9 relational expression numerical values (2*SD2) / R2 1.71 SD4 / SAG4 1.55 F / F4 0.42 (T9 / MNG5)*(MNG6 / T11) 4.51 T7 / (T6+T8) 15.85 MNG6 / T11 2.10 |SAG14| 1.20 mm

[0058] In this way, through the combination of lenses, the seven-element imaging lens of this embodiment can achieve good image quality. Its field curvature and distortion diagrams can be seen in Figures 8 and 9, clearly demonstrating that this embodiment has good imaging effect.

[0059] Please refer to Figure 10, which illustrates the fourth embodiment of this invention. Its lens configuration is largely the same as the first embodiment, with the main difference being that the image-side surface of the sixth lens 60 is concave. The design parameters of the seven-element imaging lens in this embodiment are shown in Table 10 below:

[0060] Table 10 Fourth embodiment The system has a focal length of 2.35 mm, a length of 25.01 mm, and a maximum angle of view of 168°. The aperture is f / 1.8, the maximum image height is 4.16 mm, and the entrance pupil diameter is 1.31 mm. lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (V / Vd) Focal length (mm) First lens Side view 1 16.91 0.52 1.83 42.73 -12.34 Like the side view 2 6.33 1.60 Second lens 3rd side of the object 6.67 1.17 1.54 55.71 -7.60 Like the side view 4 2.38 3.24 Third lens 5 sides of the object -7.23 1.67 1.54 55.71 -5.80 Like the side view 6 5.91 0.10 Fourth lens 7 sides of the object 5.10 4.05 2.00 25.43 5.37 Like the side view 8 52.16 0.22 aperture ∞ -0.14 Fifth lens 9 sides of the object 3.70 2.57 1.54 56.12 3.52 Like the side view 10 -2.93 0.18 Sixth lens 11 Side of the object -2.00 1.26 1.66 20.38 -2.86 Like the side view 12 52.54 0.14 Seventh Lens 13 sides of the object 3.18 4.67 1.54 55.71 4.45 Like the side view 14 -4.70 1.00 Flat lenses 15 on the side of the object ∞ 0.70 Like the side view 16 ∞ 2.05

[0061] The parameters of each aspherical surface in this embodiment are shown in Table 11 below:

[0062] Table 11 3rd side of the object Like the side view 4 5 sides of the object Like the side view 6 k 0.00E+00 -1.98E+00 2.36E+00 2.55E+00 B -2.79E-03 4.57E-03 -7.09E-03 -7.90E-03 C 9.94E-05 -5.47E-04 1.49E-03 1.42E-03 D -2.29E-06 4.12E-05 -1.07E-04 -1.31E-04 E 1.87E-08 -8.24E-07 3.33E-06 3.06E-06 F 0.00E+00 0.00E+00 0.00E+00 0.00E+00 G 0.00E+00 0.00E+00 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Side of the object 9 Like the side view 10 Side view of the object 11 Like the side view 12 k 1.59E+00 -1.34E+01 -5.14E+00 0.00E+00 B -5.14E-03 -3.03E-02 -4.45E-03 2.69E-03 C -6.45E-03 9.89E-03 -2.97E-03 1.69E-03 D 3.41E-03 -3.77E-03 1.55E-03 -4.76E-04 E -1.08E-03 7.12E-04 -6.74E-04 5.67E-05 F 1.56E-04 -6.52E-05 1.34E-04 -2.36E-06 G -1.07E-05 2.55E-06 -8.71E-06 0.00E+00 H 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Side of the object 13 Like the side view 14 k -1.08E+01 0.00E+00 B 2.46E-03 3.41E-03 C -1.73E-04 -1.61E-04 D -6.38E-06 2.48E-05 E 1.70E-06 -1.82E-06 F -5.90E-08 5.51E-08 G 0.00E+00 0.00E+00 H 0.00E+00 0.00E+00

[0063] Based on Tables 10 and 11, the numerical values ​​of the relational formulas in Table 12 below can be obtained:

[0064] Table 12 relational expression numerical values (2*SD2) / R2 1.71 SD4 / SAG4 1.56 F / F4 0.44 (T9 / MNG5)*(MNG6 / T11) 4.73 T7 / (T6+T8) 12.62 MNG6 / T11 2.04 |SAG14| 1.40 mm

[0065] In this way, through the combination of lenses, the seven-element imaging lens of this embodiment can achieve good image quality. Its field curvature and distortion diagrams can be seen in Figures 11 and 12, showing that this embodiment has good imaging effect.

[0066] Please refer to Figure 13, which illustrates the fifth embodiment of this invention. Its lens configuration is largely the same as the first embodiment, with the main difference being that the image-side surface of the fourth lens 40 is convex. The design parameters of the seven-element imaging lens in this embodiment are shown in Table 13 below:

[0067] Table Thirteen Fifth embodiment The system has a focal length of 1.42 mm, a length of 14.67 mm, and a maximum angle of view of 180°. The aperture is f / 1.82, the maximum image height is 2.90 mm, and the entrance pupil diameter is 0.78 mm. lens noodle Radius of curvature (mm) Distance (mm) Refractive index (Nd) Dispersion coefficient (V / Vd) Focal length (mm) First lens Side view 1 9.73 0.55 1.82 46.54 -9.14 Like the side view 2 4.13 1.34 Second lens 3rd side of the object 4.24 1.03 1.54 55.71 -4.10 Like the side view 4 1.33 1.98 Third lens 5 sides of the object -4.32 0.60 1.54 55.71 -3.44 Like the side view 6 3.41 0.04 Fourth lens 7 sides of the object 3.41 1.78 2.00 25.47 3.02 Like the side view 8 -22.57 0.04 aperture ∞ 0.06 Fifth lens 9 sides of the object 2.62 1.67 1.54 55.71 2.20 Like the side view 10 -1.68 0.07 Sixth lens 11 Side of the object -1.14 0.59 1.64 23.50 -2.46 Like the side view 12 -4.75 0.07 Seventh Lens 13 sides of the object 3.80 2.18 1.54 55.71 3.40 Like the side view 14 -2.83 0.83 Flat lenses 15 on the side of the object ∞ 0.60 Like the side view 16 ∞ 1.24

[0068] The parameters of each aspherical surface in this embodiment are shown in Table XIV below:

[0069] Table 14 3rd side of the object Like the side view 4 5 sides of the object Like the side view 6 k -5.12E-01 -8.47E-01 3.97E+00 -3.15E+01 B -1.09E-02 -1.43E-02 -6.31E-02 1.39E-02 C 1.21E-03 3.36E-03 5.65E-02 -4.64E-03 D -7.37E-05 -9.10E-04 -3.00E-02 -2.06E-03 E 1.87E-06 2.78E-04 1.16E-02 1.12E-02 F 9.20E-09 9.76E-06 -2.64E-03 -9.24E-03 G 0.00E+00 -3.22E-06 2.78E-04 3.32E-03 H 0.00E+00 -2.63E-06 -4.02E-06 -4.81E-04 9 sides of the object Like the side view 10 11 Side of the object Like the side view 12 k 5.96E-01 -2.40E+00 -5.01E-01 -1.64E+02 B -3.39E-02 -1.21E-01 1.50E-01 5.14E-02 C -7.36E-03 7.40E-02 -4.09E-02 -5.43E-03 D 8.45E-04 -3.52E-02 3.81E-03 -3.05E-03 E 3.02E-03 3.06E-03 5.02E-03 5.98E-04 F 6.00E-03 3.16E-03 -2.86E-03 1.96E-04 G -1.20E-02 -1.84E-03 1.26E-03 -7.48E-05 H 4.32E-03 4.60E-04 -1.07E-04 5.45E-06 13 sides of the object Like the side view 14 k -4.72E+00 -3.53E-01 B -2.57E-02 2.37E-03 C 1.13E-02 -1.74E-03 D -1.40E-03 1.84E-03 E -2.55E-04 -6.58E-04 F 9.29E-05 1.39E-04 G -5.79E-06 -1.25E-05 H -3.46E-07 2.90E-07

[0070] Based on Tables 13 and 14, the numerical values ​​of the relational formulas in Table 15 below can be obtained:

[0071] Table 15 relational expression numerical values (2*SD2) / R2 1.82 SD4 / SAG4 1.37 F / F4 0.47 (T9 / MNG5)*(MNG6 / T11) 6.33 T7 / (T6+T8) 21.17 MNG6 / T11 4.34 |SAG14| 1.57

[0072] In this way, through the combination of lenses, the seven-element imaging lens of this embodiment can achieve good image quality. Its field curvature and distortion diagrams can be seen in Figures 14 and 15, which clearly show that this embodiment has good imaging effect. [, , ]

[0073] 10: First Lens 20: Second lens 30: Third lens 40: Fourth lens 50: Fifth Lens 60: The sixth lens 70: The Seventh Lens 80: Flat lens A: Object side B: Image side G1: Front Mirror Group G2: Rear Mirror Group ST: Aperture L: Optical axis

Claims

1. A seven-element imaging lens, comprising, from the object side to the image side, the following elements in sequence: A front lens group, comprising a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side, the front lens group having negative refractive power as a whole, the image side of the first lens being concave, the image side of the second lens being concave, and the image side of the third lens being concave; an aperture. And a rear lens group, including a fifth lens, a sixth lens and a seventh lens arranged sequentially from the object side to the image side. The rear lens group as a whole has positive refractive power. The object side and image side of the fifth lens are both convex, and the object side and image side of the seventh lens are both convex. The seven-element imaging lens further satisfies the following relationship: 10 < T7 / (T6+T8) < 22; where T7 is the thickness of the fourth lens on the optical axis, T6 is the gap between the third and fourth lenses on the optical axis, and T8 is the gap between the fourth and fifth lenses on the optical axis.

2. The seven-element imaging lens as described in claim 1 further satisfies the following relationship: 1.6 < (2*SD2) / R2 < 1.85; where SD2 is the height of the first lens at the maximum viewing angle in the direction perpendicular to the optical axis, and R2 is the radius of curvature of the first lens's image side surface.

3. The seven-element imaging lens as described in claim 1 further satisfies the following relationship: 1.3 < SD4 / SAG4 < 1.6; where SD4 is the height of the second lens at the maximum viewing angle in the direction perpendicular to the optical axis, and SAG4 is the distance between the intersection of the second lens's image side on the optical axis and the maximum viewing angle of the second lens's image side in the direction parallel to the optical axis.

4. The seven-element imaging lens as described in claim 1 further satisfies the following relationship: 0.3 < F / F4 < 0.6; where F is the system focal length of the seven-element imaging lens and F4 is the focal length of the fourth lens element.

5. The seven-element imaging lens as described in claim 1 further satisfies the following relationship: 3.5 < (T9 / MNG5) * (MNG6 / T11) < 6.5; where MNG5 is the thickness of the fifth lens at its maximum viewing angle, MNG6 is the thickness of the sixth lens at its maximum viewing angle, T9 is the thickness of the fifth lens on the optical axis, and T11 is the thickness of the sixth lens on the optical axis.

6. The seven-element imaging lens as described in claim 1 further satisfies the following relationship: 2 < MNG6 / T11 < 4.5; where MNG6 is the thickness of the sixth lens at its maximum viewing angle, and T11 is the thickness of the sixth lens on the optical axis.

7. The seven-element imaging lens as described in claim 1 further satisfies the following relationship: 1 mm < |SAG14| < 2 mm; where SAG14 is the distance in the direction parallel to the optical axis between the intersection of the image side of the seventh lens on the optical axis and the maximum viewing angle of the image side of the seventh lens.

8. The seven-element imaging lens as claimed in claim 1, wherein the first lens has negative refractive power.

9. The seven-element imaging lens as claimed in claim 1, wherein the second lens has negative refractive power.

10. The seven-element imaging lens as claimed in claim 1, wherein the third lens has negative refractive power.

11. The seven-element imaging lens as claimed in claim 1, wherein the fourth lens has positive refractive power.

12. The seven-element imaging lens as claimed in claim 1, wherein the fifth lens has positive refractive power.

13. The seven-element imaging lens as claimed in claim 1, wherein the sixth lens has negative refractive power.

14. The seven-element imaging lens as claimed in claim 1, wherein the seventh lens has positive refractive power.

15. The seven-element imaging lens as claimed in claim 1, wherein the object-side surface of the first lens is convex.

16. The seven-element imaging lens as claimed in claim 1, wherein the object-side surface of the second lens is convex.

17. The seven-element imaging lens as claimed in claim 1, wherein the object-side surface of the third lens is concave.

18. The seven-element imaging lens as claimed in claim 1, wherein the object-side surface of the fourth lens is convex.

19. The seven-element imaging lens as claimed in claim 1, wherein the image-side surface of the fourth lens is convex or concave.

20. The seven-element imaging lens as claimed in claim 1, wherein the object-side surface of the sixth lens element is concave.

21. The seven-element imaging lens as claimed in claim 1, wherein the image-side surface of the sixth lens is convex or concave.

Images