OPTICAL IMAGING LENS

Description

BACKGROUND OF THE INVENTION
Technical Field

The present invention generally relates to an optical image capturing system, and more particularly to an optical imaging lens, which provides a better optical performance of high image quality and low distortion.

Description of Related Art

In recent years, with advancements in portable electronic devices having camera functionalities, the demand for an optical image capturing system is raised gradually. The image sensing device of the ordinary photographing camera is commonly selected from a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor sensor (CMOS Sensor). Besides, as advanced semiconductor manufacturing technology enables the minimization of the pixel size of the image sensing device, the development of the optical image capturing system towards the field of high pixels. Moreover, with the advancement in drones and driverless autonomous vehicles, Advanced Driver Assistance System (ADAS) plays an important role, collecting environmental information through various lenses and sensors to ensure the driving safety of the driver. Furthermore, as the image quality of the automotive lens changes with the temperature of an external application environment, the temperature requirements of the automotive lens also increase. Therefore, the requirement for high imaging quality is rapidly raised.

Good imaging lenses generally have the advantages of low distortion, high resolution, etc. In practice, small size and cost must be considered. Therefore, it is a big problem for designers to design a lens with good imaging quality under various constraints.

BRIEF SUMMARY OF THE INVENTION

In view of the reasons mentioned above, the primary objective of the present invention is to provide an optical imaging lens that provides a better optical performance of high image quality.

The present invention provides an optical imaging lens, in order from an object side to an image side along an optical axis, including a first lens assembly, an aperture, and a second lens assembly, wherein the first lens assembly includes, in order from the object side to the image side along the optical axis, a first lens having negative refractive power, a second lens having negative refractive power, and a third lens having positive refractive power, wherein an object-side surface of the first lens is a convex surface toward the object side, and an image-side surface of the first lens is a concave surface toward the image side; an object-side surface of the second lens is a concave surface toward the object side, and an image-side surface of the second lens is a convex surface toward the image side: the object-side surface of the second lens and/or the image-side surface of the second lens are/is an aspheric surface: an object-side surface of the third lens is a convex surface toward the object side. The second lens assembly includes, in order from the object side to the image side along the optical axis, a fourth lens that is a biconvex lens having positive refractive power, a fifth lens that is a biconvex lens having negative refractive power, a sixth lens that is a biconcave lens having negative refractive power, and a seventh lens having positive refractive power, wherein an object-side surface of the fourth lens and/or an image-side surface of the fourth lens are/is an aspheric surface; an object-side surface of the sixth lens and an image-side surface of the fifth lens are adhered to form a compound lens having negative refractive power; an object-side surface of the seventh lens is a convex surface toward the object side, and an image-side surface of the seventh lens is a concave surface toward the image side: the object-side surface of the seventh lens and/or the image-side surface of the seventh lens are/is an aspheric surface. The optical imaging lens satisfies: -0.05<F/fg1<0.3; F is a focal length of the optical imaging lens and fg1 is a focal length of the first lens assembly.

The present invention further provides an optical imaging lens, in order from an object side to an image side along an optical axis, including a first lens assembly, an aperture, and a second lens assembly, wherein the first lens assembly includes, in order from the object side to the image side along the optical axis, a first lens having negative refractive power, a second lens that is a biconcave lens having negative refractive power, and a third lens that is a biconvex lens having positive refractive power, wherein an object-side surface of the first lens is a convex surface toward the object side, and an image-side surface of the first lens is a concave surface toward the image side; an object-side surface of the second lens and/or an image-side surface of the second lens are/is an aspheric surface. The second lens assembly includes, in order from the object side to the image side along the optical axis, a fourth lens that is a biconvex lens having positive refractive power, a fifth lens that is a biconvex lens having negative refractive power, a sixth lens that is a biconcave lens having negative refractive power, and a seventh lens that is a biconvex lens having positive refractive power, wherein an object-side surface of the sixth lens and an image-side surface of the fifth lens are adhered to form a compound lens having negative refractive power; an object-side surface of the seventh lens and/or an image-side surface of the seventh lens are/is an aspheric surface. The optical imaging lens satisfies: 0.35<F/fg2<0.5; F is a focal length of the optical imaging lens and fg2 is a focal length of the second lens assembly.

With the aforementioned design, the optical imaging lens could effectively improve an aberration of the optical imaging lens by utilizing design of the mirror shape, the refractive power arrangement, and focal length of the seven lenses, thereby achieving the effect of high image quality.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which

FIG. 1A is a schematic view of the optical imaging lens according to a first embodiment of the present invention;

FIG. 1B is a diagram showing the longitudinal spherical aberration of the optical imaging lens according to the first embodiment of the present invention;

FIG. 1C is a diagram showing the lateral spherical aberration of the optical imaging lens according to the first embodiment of the present invention:

FIG. 2A is a schematic view of the optical imaging lens according to a second embodiment of the present invention;

FIG. 2B is a diagram showing the longitudinal spherical aberration of the optical imaging lens according to the second embodiment of the present invention;

FIG. 2C is a diagram showing the lateral spherical aberration of the optical imaging lens according to the second embodiment of the present invention:

FIG. 3A is a schematic view of the optical imaging lens according to a third embodiment of the present invention;

FIG. 3B is a diagram showing the longitudinal spherical aberration of the optical imaging lens according to the third embodiment of the present invention; and

FIG. 3C is a diagram showing the lateral spherical aberration of the optical imaging lens according to the third embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

An optical imaging lens 100 according to a first embodiment of the present invention is illustrated in FIG. 1A, which includes, in order along an optical axis Z from an object side to an image side, a first lens assembly G1, an aperture ST, and a second lens assembly G2. In the current embodiment, the first lens assembly G1 includes, in order along the optical axis Z from the object side to the image side, a first lens L1, a second lens L2, and a third lens L3: the second lens assembly G2 includes, in order along the optical axis Z from the object side to the image side, a fourth lens L4. a fifth lens L5, a sixth lens L6, and a seventh lens L7.

The first lens L1 is a negative meniscus with negative refractive power; an object-side surface S1 of the first lens L1 is a convex surface toward the object side, and an image-side surface S2 of the first lens L1 is a concave surface toward the image side. As shown in FIG. 1A, a part of a surface of the first lens L1 toward the image side is recessed to form the image-side surface S2, and the optical axis Z passes through the object-side surface S1 and the image-side surface S2 of the first lens L1.

The second lens L2 is a negative meniscus with negative refractive power. As shown in FIG. 1A, an object-side surface S3 of the second lens L2 is a concave surface toward the object side, and an image-side surface S4 of the second lens L2 is a convex surface toward the image side; the object-side surface S3, the image-side surface S4, or both of the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric surfaces. In the current embodiment, both of the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric surfaces.

The third lens is a biconvex lens (i.e., both of an object-side surface S5 of the third lens L3 and an image-side surface S6 of the third lens L3 are convex surfaces) with positive refractive power, wherein the object-side surface S5 of the third lens L3 is slightly convex toward the object side, and the image-side surface S6 of the third lens L3 is convex toward the image side in an arc shape.

The fifth lens L5 is a biconvex lens (i.e., both of an object-side surface S9 of the fifth lens L5 and an image-side surface S10 of the fifth lens L5 are convex surfaces) with negative refractive power. As shown in FIG. 1A,, the object-side surface S9 of the fifth lens L5 is slightly convex toward the object side, and the image-side surface S10 of the fifth lens L5 is convex toward the image side in an arc shape.

The sixth lens L6 is a biconcave lens (i.e., both of an object-side surface S11 of the sixth lens L6 and an image-side surface S12 of the sixth lens L6 are concave surfaces) with negative refractive power, wherein the object-side surface S11 of the sixth lens L6 and the image-side surface S10 of the fifth lens L5 are adhered to form a same surface, thereby the fifth lens L5 is engaged with the sixth lens L6 to form a compound lens with negative refractive power. As shown in FIG. 1A, a part of a surface of the sixth lens L6 toward the object side is recessed to form the object-side surface S11, and the optical axis Z passes through the object-side surface S11 and the image-side surface S12 of the sixth lens L6.

The seventh lens L7 is a positive meniscus with positive refractive power; an object-side surface S13 of the seventh lens L7 is a convex surface toward the object side, and an image-side surface S14 of the seventh lens L7 is a concave surface toward the image side; the object-side surface S13, the image-side surface S14, or both of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 are aspheric surfaces. As shown in FIG. 1A, a part of a surface of the sixth lens L6 toward the image side is recessed to form the image-side surface S14, and the optical axis Z passes through the object-side surface S13 and the image-side surface S14 of the seventh lens L7; both of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 are aspheric surfaces.

Additionally, the optical imaging lens 100 further includes an infrared filter L8 and a protective glass L9, wherein the infrared filter L8 is disposed between the seventh lens L7 and the protective glass L9, thereby filtering out excess infrared rays in an image light passing through the first lens assembly G1 and the second lens assembly G2. The protective glass L9 for protecting the infrared filter L8 is disposed between the infrared filter L8 and an image plane Im of the optical imaging lens 100 and is closer to the image plane Im than the infrared filter L8.

In order to keep the optical imaging lens 100 in good optical performance and high imaging quality, the optical imaging lens 100 further satisfies:

(1) -0.05<F/fg1<0.3;
(2) -0.65<F/fl<-0.45; -0.25<F/f2<-0.1; 0.25<F/f3<0.42;
(3) 0.35<F/fg2<0.5;
(4) 0.25<F/f4<0.45; -0.1<F/f5<0.1; -0.45<F/f6<-0.25; 0.1<F/f7<0.35;
(5) -0.3<F/f56<-0.05;

wherein F is a focal length of the optical imaging lens 100; f1 is a focal length of the first lens L1: f2 is a focal length of the second lens L2; f3 is a focal length of the third lens L3: f4 is a focal length of the fourth lens L4; f5 is a focal length of the fifth lens L5; f6 is a focal length of the sixth lens L6; f56 is a focal length of a compound lens formed by adhering the fifth lens L5 and the sixth lens L6; f7 is a focal length of the seventh lens L7; fg1 is a focal length of the first lens assembly G1; fg2 is a focal length of the second lens assembly G2.

Parameters of the optical imaging lens 100 of the first embodiment of the present invention are listed in following Table 1, including the focal length F of the optical imaging lens 100 (also called an effective focal length (EFL)), a F-number(Fno), a maximal field of view (FOV), a radius of curvature (R) of each lens, a distance (D) between each surface and the next surface on the optical axis Z, a refractive index (Nd) of each lens, an Abbe number (Vd) of each lens, the focal length of each lens, the focal length (cemented focal length) of the compound lens formed by adhering the fifth lens L5 and the sixth lens L6, wherein a unit of the focal length, the radius of curvature, and the distance is millimeter (mm). The data listed below are not a limitation of the present invention, wherein the parameters that could be appropriate changed by one with ordinary skill in the art after referring the present invention should still fall within the scope of the present invention.

TABLE 1

F=5.2 mm; Fno=2.1; FOV=112.6 deg

Surface
R(mm)
D(mm)
Nd
Vd
Focal length
Cemented focal length
Note

S1
52.25
1.20
1.74
49.3994
-8.8855

L1

S2
5.82
4.54

S3
-7.56
4.40
1.88
37.2213
-34.924

L2

S4
-12.74
1.69

S5
57.72
4.04
1.59
48.4459
17.747

L3

S6
-12.49
1.77

ST
Infinity
1.05

ST

S7
20.871
1.98
1.46
67.8267
14.938

L4

S8
-9.93
2.14

S9
45.02
4.52
1.65
55.9038
-57.366
-18.264
L5

S10, S11
-6.01
2.55
1.85
23.8256
-13.714

L6

S12
22.50
1.51

S13
12.18
2.60
1.80
41.1438
16.69

L7

S14
124.80
1

S15
Infinity
0.4
1.52
64.17

Infrared filter L8

S16
Infinity
2.26

S17
Infinity
0.5
1.52
64.17

Protective glass L9

S18
Infinity
0.435

Im
Infinity

Im

It can be seen from Table 1 that, in the current embodiment, the focal length F of the optical imaging lens 100 is 5.2 mm, and the Fno is 2.1, and the FOV is 112.6 degrees, wherein f1 =-8.8855 mm: f2=-34.924 mm; f3=17.747 mm; f4=14.938 mm; f5=-57.366 mm: f6=-13.714 mm; f7=16.69 mm; f56=-18.264 mm; fgl=67.23 mm; fg2=14.89 mm.

Additionally, based on the above detailed parameters, detailed values of the aforementioned conditional formula in the first embodiment are as follows: F/fgl=-0.08; F/f1=-0.59; F/f2=-0.15; F/f3=0.29; F/fg2=0.35; F/f4=0.35; F/f5=-0.09; F/f6=–0.38; F/f7=0.31; F/f56=-0.28.

With the aforementioned design, the first lens assembly G1 and the second lens assembly G2 satisfy the aforementioned conditions (1) to (5) of the optical imaging lens 100.

Moreover, an aspheric surface contour shape Z of each of the object-side surface S3 of the second lens L2. and the image-side surface S4 of the second lens L2, and the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4, and the object-side surface S13 of the seventh lens L7, and the image-side surface S14 of the seventh lens L7 of the optical imaging lens 100 according to the first embodiment could be obtained by following formula:

$\begin{array}{l} Z = \frac{c h^{2}}{1 + \sqrt{1 - (1 + k) c^{2} h^{2}}} + A_{4} h^{4} + A_{6} h^{6} + A_{8} h^{8} + A_{10} h^{10} + \\ A_{12} h^{12} + A_{14} h^{14} + A_{16} h^{16} \end{array}$

wherein Z is aspheric surface contour shape; c is reciprocal of radius of curvature: h is half the off-axis height of the surface; k is conic constant: A4, A6, A8, A10, A12, A14, and A16 respectively represents different order coefficient of h.

The conic constant k of each of the object-side surface S3 of the second lens L2, and the image-side surface S4 of the second lens L2. and the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4, and the object-side surface S13 of the seventh lens L7, and the image-side surface S14 of the seventh lens L7 of the optical imaging lens 100 according to the first embodiment and the different order coefficient of A4, A6, A8, A10, A12, A14, and A16 are listed in following Table 2 to Table 4:

TABLE 2

Surface
S3
S4

k
-6.8394E-01
-1.0047E+01

A4
-2.0522E-04
1.0690E-04

A6
2.3985E-05
9.4079E-06

A8
-7.0003E-07
-3.4953E-07

A10
1.6620E-08
7.1361E-09

A12
0
0

A14
0
0

A16
0
0

TABLE 3

Surface
S7
S8

k
0
0

A4
1.6786E-04
7.2968E-05

A6
-9.0987E-06
-1.0077E-05

A8
1.0574E-07
3.4837E-07

A10
-5.1905E-08
-7.1222E-08

A12
0
0

A14
0
0

A16
0
0

TABLE 4

Surface
S13
S14

k
1.2559E+00
0

A4
4.2040E-04
1.2627E-04

A6
1.177 1E-05
7.8887E-06

A8
1.9976E-07
-7.1154E-09

A10
0
0

A12
0
0

A14
0
0

A16
0
0

Taking optical simulation data to verify the imaging quality of the optical imaging lens 100, wherein FIG. 1B is a diagram showing the longitudinal spherical aberration according to the first embodiment; FIG. 1C is a diagram showing the lateral spherical aberration according to the first embodiment. The graphics shown in FIG. 1B and FIG. 1C are within a standard range. In this way, the optical imaging lens 100 of the first embodiment could effectively enhance image quality.

An optical imaging lens 200 according to a second embodiment of the present invention is illustrated in FIG. 2A, which includes, in order along an optical axis Z from an object side to an image side, a first lens assembly G1, an aperture ST, and a second lens assembly G2. In the current embodiment, the first lens assembly G1 includes, in order along the optical axis Z from the object side to the image side, a first lens L1, a second lens L2, and a third lens L3: the second lens assembly G2 includes, in order along the optical axis Z from the object side to the image side, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

The first lens L1 is a negative meniscus with negative refractive power; an object-side surface S1 of the first lens L1 is a convex surface toward the object side, and an image-side surface S2 of the first lens L1 is a concave surface toward the image side. As shown in FIG. 2A,a part of a surface of the first lens L1 toward the image side is recessed to form the image-side surface S2, and the optical axis Z passes through the object-side surface S1 and the image-side surface S2 of the first lens L1.

The second lens L2 is a concave-convex lens with negative refractive power, wherein an object-side surface S3 of the second lens L2 is a concave surface toward the object side, and an image-side surface S4 of the second lens L2 is a convex surface toward the image side; the object-side surface S3, the image-side surface S4, or both of the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric surfaces. In the current embodiment, both of the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric surfaces.

The third lens is a positive meniscus with positive refractive power, wherein an object-side surface S5 of the third lens L3 is a convex surface toward the object side, and an image-side surface S6 of the third lens L3 is a concave surface or a flat surface toward the image side. As shown in FIG. 2A, the image-side surface S6 of the third lens L3 is a concave surface sligjtly recessed.

The fourth lens L4 is a biconvex lens (i.e., both of an object-side surface S7 of the fourth lens L4 and an image-side surface S8 of the fourth lens L4 are convex surfaces) with positive refractive power: the object-side surface S7, the image-side surface S8. or both of the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric surfaces. As shown in FIG. 2A, a part of a surface of the fourth lens L4 toward the object side is convex to form the object-side surface S7. and the optical axis Z passes through the object-side surface S7 and the image-side surface S8 of the fourth lens L4; both of the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric surfaces.

The sixth lens L6 is a biconcave lens (i.e., both of an object-side surface S11 of the sixth lens L6 and an image-side surface S12 of the sixth lens L6 are concave surfaces) with negative refractive power, wherein the object-side surface S11 of the sixth lens L6 and the image-side surface S10 of the fifth lens L5 are adhered to form a same surface, thereby the fifth lens L5 is engaged with the sixth lens L6 to form a compound lens with negative refractive power. As shown in FIG. 2A, a part of a surface of the sixth lens L6 toward the object side is recessed to form the object-side surface S11, and the optical axis Z passes through the object-side surface S11 and the image-side surface S12 of the sixth lens L6.

The seventh lens L7 is a convex-concave lens with positive refractive power, an object-side surface S13 of the seventh lens L7 is a convex surface toward the object side, and an image-side surface S14 of the seventh lens L7 is a concave surface toward the image side: the object-side surface S13, the image-side surface S14, or both of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 are aspheric surfaces. As shown in FIG. 2A, a part of a surface of the seventh lens L7 toward the image side is recessed to form the image-side surface S14, and the optical axis Z passes through the object-side surface S 13 and the image-side surface S14 of the seventh lens L7; both of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 are aspheric surfaces.

Additionally, the optical imaging lens 200 further includes an infrared filter L8 and a protective glass L9, wherein the infrared filter L8 is disposed between the seventh lens L7 and the protective glass L9 and is closer to the protective glass L9 than the image-side surface S14 of the seventh lens L7. thereby filtering out excess infrared rays in an image light passing through the first lens assembly G1 and the second lens assembly G2. The protective glass L9 for protecting the infrared filter L8 is disposed between the infrared filter L8 and an image plane Im of the optical imaging lens 200 and is closer to the infrared filter L8 than the image plane Im is closer to the image plane Im than the infrared filter L8.

In order to keep the optical imaging lens 200 in good optical performance and high imaging quality, the optical imaging lens 200 further satisfies:

(1) -0.05<F/fg1<0.3;
(2) -0.65<F/fl<-0.45; -0.25<F/f2<-0.1; 0.25<F/f3<0.42;
(3) 0.35<F/fg2<0.5;
(4) 0.25<F/f4<0.45; -0.1<F/f5<0.1; -0.45<F/f6<-0.25; 0.1<F/f7<0.35;
(5) -0.3<F/f56<-0.05;

wherein F is a focal length of the optical imaging lens 200; f1 is a focal length of the first lens L1; f2 is a focal length of the second lens L2; f3 is a focal length of the third lens L3; f4 is a focal length of the fourth lens L4; f5 is a focal length of the fifth lens L5; f6 is a focal length of the sixth lens L6, f56 is a focal length of a compound lens formed by adhering the fifth lens L5 and the sixth lens L6; f7 is a focal length of the seventh lens L7; fg1 is a focal length of the first lens assembly G1; fg2 is a focal length of the second lens assembly G2.

Parameters of the optical imaging lens 200 of the second embodiment of the present invention are listed in following Table 5. including the focal length F of the optical imaging lens 200 (also called an effective focal length (EFL)), a F-number (Fno), a maximal field of view (FOV), a radius of curvature (R) of each lens, a distance (D) between each surface and the next surface on the optical axis Z. a refractive index (Nd) of each lens, an Abbe number (Vd) of each lens, the focal length of each lens, the focal length (cemented focal length) of the compound lens formed by adhering the fifth lens L5 and the sixth lens L6, wherein a unit of the focal length, the radius of curvature, and the distance is millimeter (mm). The data listed below are not a limitation of the present invention, wherein the parameters that could be appropriate changed by one with ordinary skill in the art after referring the present invention should still fall within the scope of the present invention.

TABLE 5

F=5 mm: Fno=2; FOV=156 deg

Surface
R(mm)
D(mm)
Nd
Vd
Focal length
Cemented focal length
Note

S1
31.9849
1.50
1.834809
42.7437
-10.37

L1

S2
6.68845
4.55

S3
-6.6863
4.01
1.785896
44.2026
-24.97

L2

S4
-12.798
1.38

S5
11.851
3.37
1.7936
37.0895
16.44

L3

S6
107.9
1.61

ST
Infinity
1.05

ST

S7
14.235
3.98
1.48749
70.2363
12.83

L4

S8
-10.184
0.10

S9
16.2532
3.31
1.651133
55.8889
95.29
-71.28
L5

S10, S11
-6. 186
1.12
1.84666
23.7779
-16.76

L6

S12
31.7653
1.96

S13
10.8104
2.56
1.799516
42.225
36.05

L7

S14
15.436
1.00

S15
Infinity
0.4
1.52
64.17

Infrared filter L8

S16
Infinity
1.91

S17
Infinity
0.50
1.52
64.17

Protective glass L9

S18
Infinity
0.20

Im
Infinity

Im

It can be seen from Table 5 that, in the second embodiment, the focal length (F) of the optical imaging lens 200 is 5 mm, and the Fno is 2, and the FOV is 156 degrees, wherein fl=--10.37 mm: f2=-24.97 mm; f3=16.44 mm; f4=12.83 mm; f5=95.29 mm; f6=-16.76 mm; f7=36.05 mm; f56=-71.28 mm; fg1=-126; fg2=10.59 mm.

Additionally, based on the above detailed parameters, detailed values of the aforementioned conditional formula in the second embodiment are as follows: F/fg1=-0.04; F/f1=-0.48; F/f2=-0.20; F/f3=0.30; F/fg2=0.47; F/f4=0.39; F/f5=0.05; F/f6=-0.30; F/f7=0.14; F/f56=-0.07.

With the aforementioned design, the first lens assembly G1 and the second lens assembly G2 satisfy the aforementioned conditions (1) to (5) of the optical imaging lens 200.

Moreover, an aspheric surface contour shape Z of each of the object-side surface S3 of the second lens L2, and the image-side surface S4 of the second lens L2, and the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4, and the object-side surface S13 of the seventh lens L7, and the image-side surface S14 of the seventh lens L7 of the optical imaging lens 200 according to the second embodiment could be obtained by following formula:

$\begin{array}{l} Z = \frac{c h^{2}}{1 + \sqrt{1 - (1 + k) c^{2} h^{2}}} + A_{4} h^{4} + A_{6} h^{6} + A_{8} h^{8} + A_{10} h^{10} + \\ A_{12} h^{12} + A_{14} h^{14} + A_{16} h^{16} \end{array}$

wherein Z is aspheric surface contour shape: c is reciprocal of radius of curvature; h is half the off-axis height of the surface; k is conic constant; A4, A6, A8, A10, A12, A14, and A16 respectively represents different order coefficient of h.

The conic constant k of each of the object-side surface S3 of the second lens L2, and the image-side surface S4 of the second lens L2, and the object-side surface S7 of the fourth lens L4. and the image-side surface S8 of the fourth lens L4. and the object-side surface S13 of the seventh lens L7, and the image-side surface S14 of the seventh lens L7 of the optical imaging lens 200 according to the second embodiment and the different order coefficient of A4, A6, A8, A10, A12, A14, and A16 are listed in following Table 6 to Table 8:

TABLE 6

Surface
S3
S4

k
-6.0362E-01
-1.0000E+01

A4
4.7391E-04
-5.6051E-05

A6
8.5082E-06
2.0568E-05

A8
-1.7595E-07
-4.0019E-07

A10
3.0569E-09
1.4152E-08

A12
0
0

A14
0
0

A16
0
0

TABLE 7

Surface
S7
S8

k
-1.9204E-01
1.1245E+00

A4
1.1009E-04
3.3609E-04

A6
-1.7446E-06
-2.2640E-07

A8
1.5886E-07
1.0488E-07

A10
0
0

A12
0
0

A14
0
0

A16
0
0

TABLE 8

Surface
S13
S14

k
-4.9404E-01
1 1245E+00

A4
-1.0473E-04
-1.5106E-04

A6
6.0890E-08
-7.3729E-06

A8
-1.2947E-07
-1.7138E-07

A10
0
0

A12
0
0

A14
0
0

A16
0
0

Taking optical simulation data to verify the imaging quality of the optical imaging lens 200, wherein FIG. 2B is a diagram showing the longitudinal spherical aberration according to the second embodiment; FIG. 2C is a diagram showing the lateral spherical aberration according to the second embodiment. The graphics shown in FIG. 2B and FIG. 2C are within a standard range. In this way, the optical imaging lens 200 of the second embodiment could effectively enhance image quality

An optical imaging lens 300 according to a third embodiment of the present invention is illustrated in FIG. 3A, which includes, in order along an optical axis Z from an object side to an image side, a first lens assembly G1, an aperture ST, and a second lens assembly G2. In the current embodiment, the first lens assembly G1 includes, in order along the optical axis Z from the object side to the image side, a first lens L1, a second lens L2, and a third lens L3; the second lens assembly G2 includes, in order along the optical axis Z from the object side to the image side, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

The first lens L1 is a negative meniscus with negative refractive power; an object-side surface S1 of the first lens L1 is a convex surface toward the object side, and an image-side surface S2 of the first lens L1 is a concave surface toward the image side. As shown in FIG. 3A, a part of a surface of the first lens L1 toward the image side is recessed to form the image-side surface S2, and the optical axis Z passes through the object-side surface S1 and the image-side surface S2 of the first lens L1.

The third lens is a biconvex lens (i.e., both of an object-side surface S5 of the third lens L3 and an image-side surface S6 of the third lens L3 are convex surfaces) with positive refractive power.

The sixth lens L6 is a biconcave lens (i.e., both of an object-side surface S11 of the sixth lens L6 and an image-side surface S12 of the sixth lens L6 are concave surfaces) with negative refractive power, wherein the object-side surface S11 of the sixth lens L6 and the image-side surface S10 of the fifth lens L5 are adhered to form a same surface, thereby the fifth lens L5 is engaged with the sixth lens L6 to form a compound lens with negative refractive power. As shown in FIG. 3A, a part of a surface of the sixth lens L6 toward the object side is recessed to form the object-side surface S11, and the optical axis Z passes through the object-side surface S11 and the image-side surface S12 of the sixth lens L6.

The seventh lens L7 is a positive meniscus with positive refractive power, wherein an object-side surface S13 of the seventh lens L7 is a convex surface toward the object side, and an image-side surface S14 of the seventh lens L7 is a concave surface toward the image side; the object-side surface S13, the image-side surface S14, or both of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 are aspheric surfaces. As shown in FIG. 3A, both of the object-side surface S13 and the image-side surface S14 of the seventh lens L7 are aspheric surfaces.

Additionally, the optical imaging lens 300 further includes an infrared filter L8 and a protective glass L9, wherein the infrared filter L8 is disposed between the seventh lens L7 and the protective glass L9 and is closer to the image-side surface S14 of the seventh lens L7 than the protective glass L9, thereby filtering out excess infrared rays in an image light passing through the first lens assembly G1 and the second lens assembly G2. The protective glass L9 for protecting the infrared filter L8 is disposed between the infrared filter L8 and an image plane Im of the optical imaging lens 300 and is closer to the image plane Im than the infrared filter L8.

In order to keep the optical imaging lens 300 in good optical performance and high imaging quality, the optical imaging lens 300 further satisfies:

(1) -0.05<F/fg1<0.3;
(2) -0.65<F/fl<--0.45; -0.25<F/f2<-0.1; 0.25<F/f3<0.42;
(3) 0.35<F/fg2<0.5;
(4) 0.25<F/f4<0.45; -0.1<F/f5<0.1; -0.45<F/f6<:-0.25;
(5) -0.3<F/f56<-0.05;

wherein F is a focal length of the optical imaging lens 300; f1 is a focal length of the first lens L1; f2 is a focal length of the second lens L2; f3 is a focal length of the third lens L3; f4 is a focal length of the fourth lens L4; f5 is a focal length of the fifth lens L5; f6 is a focal length of the sixth lens L6; f56 is a focal length of a compound lens formed by adhering the fifth lens L5 and the sixth lens L6; f7 is a focal length of the seventh lens L7; fg1 is a focal length of the first lens assembly G1; fg2 is a focal length of the second lens assembly G2.

Parameters of the optical imaging lens 300 of the third embodiment of the present invention are listed in following Table 9. including the focal length F of the optical imaging lens 300 (also called an effective focal length (EFL)), a F-number (Fno), a maximal field of view (FOV), a radius of curvature (R) of each lens, a distance (D) between each surface and the next surface on the optical axis Z, a refractive index (Nd) of each lens, an Abbe number (Vd) of each lens, the focal length of each lens, the focal length (cemented focal length) of the compound lens formed by adhering the fifth lens L5 and the sixth lens L6, wherein a unit of the focal length, the radius of curvature, and the distance is millimeter (mm). The data listed below are not a limitation of the present invention, wherein the parameters that could be appropriate changed by one with ordinary skill in the art after referring the present invention should still fall within the scope of the present invention.

TABLE 9

F=4.4 mm: Fno=1.7; FOV=120 deg

Surface
R(mm)
D(mm)
Nd
Vd
Focal length
Cemented focal length
Note

S1
20.41
1.20
1.834809
42.7437
-8.50

L1

S2
5.14
4.54

S3
-6.27
4.00
1.851348
40.1045
-20.90

L2

S4
-12.50
1.36

S5
19.31
3.39
1.7936
37.0895
11.95

L3

S6
-17.34
1.61

ST
Infinity
1.20

ST

S7
60.96
4.00
1.497005
81.6333
15.38

L4

S8
-8.57
0.10

S9
19.33
3.35
1.651133
55.8889
423.98
-22.47
L5

S10, S11
-5.92
1.20
1.846663
23.8256
-11.73

L6

S12
16.92
1.86

S13
10.86
2.60
1.853702
40.5987
15.02

L7

S14
61.81
1.00

S15
Infinity
0.4
1.52
64.17

Infrared filter L8

S16
Infinity
2.26

S17
Infinity
0.50
1.52
64.17

Protective glass L9

S18
Infinity
0.34

Im
Infinity

Im

It can be seen from Table 9 that, in the current embodiment, the focal length F of the optical imaging lens 300 is 4.4 mm, and the Fno is 1.7, and the FOV is 120 degrees, wherein f1=-8.5 mm; f2=-20.9 mm; f3=11.95 mm; f4=15.38 mm; f5=423.98 mm; f6=-11.73 mm; f7=15.02 mm; f56=-22.47 mm; fg1=21.42; fg2=12.52 mm.

Additionally, based on the above detailed parameters, detailed values of the aforementioned conditional formula in the third embodiment are as follows: F/fg1=0.2; F/fl=-0.52; F/f2=-0.21; F/f3=0.37; F/fg2=0.35; F/f4-0.29; F/f5=0.01; F/f6=-0.38; F/f7=0.29; F/f56=-0.2.

With the aforementioned design, the first lens assembly G1 and the second lens assembly G2 satisfy the aforementioned conditions (1) to (5) of the optical imaging lens 300.

Moreover, an aspheric surface contour shape Z of each of the object-side surface S3 of the second lens L2. and the image-side surface S4 of the second lens L2, and the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4, and the object-side surface S13 of the seventh lens L7, and the image-side surface S14 of the seventh lens L7 of the optical imaging lens 300 according to the third embodiment could be obtained by following formula:

$\begin{array}{l} Z = \frac{c h^{2}}{1 + \sqrt{1 - (1 + k) c^{2} h^{2}}} + A_{4} h^{4} + A_{6} h^{6} + A_{8} h^{8} + A_{10} h^{10} + \\ A_{12} h^{12} + A_{14} h^{14} + A_{16} h^{16} \end{array}$

The conic constant k of each of the object-side surface S3 of the second lens L2, and the image-side surface S4 of the second lens L2, and the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4, and the object-side surface S13 of the seventh lens L7, and the image-side surface S14 of the seventh lens L7 of the optical imaging lens 300 according to the third embodiment and the different order coefficient of A4, A6, A8, A10, A12, A14, and A16 are listed in following Table 10 to Table 12:

TABLE 10

Surface
S3
S4

k
-6.8394E-01
-1.0047E+01

A4
2.3875E-04
9.1420E-06

A6
-7.0269E-06
-7.2814E-06

A8
-6.1215E-08
1.5289E-07

A10
-1.2860E-08
-3.6197E-08

A12
0
0

A14
0
0

A16
0
0

TABLE 11

Surface
S7
S8

k
0
0

A4
5.1944E-04
-5.5462E-05

A6
7.5112E-06
2.0921E-05

A8
-2.4540E-07
-4.3466E-07

A10
4.6148E-09
9.9528E-09

A12
0
0

A14
0
0

A16
0
0

TABLE 12

Surface
S13
S14

k
1.2559E+00
0

A4
2.3921E-04
8.0449E-05

A6
5.8997E-06
-6.0768E-07

A8
7.3610E-08
4.4448E-08

A10
0
0

A12
0
0

A14
0
0

A16
0
0

Taking optical simulation data to verify the imaging quality of the optical imaging lens 300, wherein FIG. 3B is a diagram showing the longitudinal spherical aberration according to the third embodiment; FIG. 3C is a diagram showing the lateral spherical aberration according to the third embodiment. The graphics shown in FIG. 3B and FIG. 3C are within a standard range. In this way, the optical imaging lens 300 of the third embodiment could effectively enhance image quality.

It must be pointed out that the embodiments described above are only some preferred embodiments of the present invention. It is noted that, the parameters listed in Tables are not a limitation of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.

Claims

1. An optical imaging lens, in order from an object side to an image side along an optical axis, comprising: a first lens assembly comprising, in order from the object side to the image side along the optical axis, a first lens having negative refractive power, a second lens having negative refractive power, and a third lens having positive refractive power, wherein an object-side surface of the first lens is a convex surface toward the object side, and an image-side surface of the first lens is a concave surface toward the image side; an object-side surface of the second lens is a concave surface toward the object side, and an image-side surface of the second lens is a convex surface toward the image side; the object-side surface of the second lens and/or the image-side surface of the second lens are/is an aspheric surface; an object-side surface of the third lens is a convex surface toward the object side;an aperture;a second lens assembly comprising, in order from the object side to the image side along the optical axis, a fourth lens that is a biconvex lens having positive refractive power, a fifth lens that is a biconvex lens having negative refractive power, a sixth lens that is a biconcave lens having negative refractive power, and a seventh lens having positive refractive power, wherein an object-side surface of the fourth lens and/or an image-side surface of the fourth lens are/is an aspheric surface; an object-side surface of the sixth lens and an image-side surface of the fifth lens are adhered to form a compound lens having negative refractive power; an object-side surface of the seventh lens is a convex surface toward the object side, and an image-side surface of the seventh lens is a concave surface toward the image side; the object-side surface of the seventh lens and/or the image-side surface of the seventh lens are/is an aspheric surface;wherein the optical imaging lens satisfies: -0.05<F/fg1<0.3; F is a focal length of the optical imaging lens and fg1 is a focal length of the first lens assembly.
2. The optical imaging lens as claimed in claim 1, wherein the optical imaging lens satisfies: -0.65<F/fl<-0.45, wherein f1 is a focal length of the first lens.
3. The optical imaging lens as claimed in claim 1, wherein the optical imaging lens satisfies: -0.25<F/f2<-0.1, wherein f2 is a focal length of the second lens.
4. The optical imaging lens as claimed in claim 1, wherein the optical imaging lens satisfies: 0.25<F/f3<0.42, wherein f3 is a focal length of the third lens.
5. The optical imaging lens as claimed in claim 1, wherein the optical imaging lens satisfies: 0.25<F/f4<0.45, wherein f4 is a focal length of the fourth lens.
6. The optical imaging lens as claimed in claim 1, wherein the optical imaging lens satisfies: -0.3<F/f56<-0.05, wherein f56 is a focal length of the compound lens formed by adhering the fifth lens and the sixth lens.
7. The optical imaging lens as claimed in claims 6, wherein the optical imaging lens satisfies: -0.1<F/f5<0.1, wherein f5 is a focal length of the fifth lens.
8. The optical imaging lens as claimed in claims 6, wherein the optical imaging lens satisfies: -0.45<F/f6<-0.25, wherein f6 is a focal length of the sixth lens.
9. The optical imaging lens as claimed in claims 1, wherein the optical imaging lens satisfies: 0.1<F/f7<0.35, wherein f7 is a focal length of the seventh lens.
10. The optical imaging lens as claimed in claims 1, wherein both of the object-side surface and the image-side surface of the second lens are aspheric surfaces.
11. The optical imaging lens as claimed in claims 1, wherein both of the object-side surface and the image-side surface of the fourth lens are aspheric surfaces.
12. The optical imaging lens as claimed in claims 1, wherein both of the object-side surface and the image-side surface of the seventh lens are aspheric surfaces.
13. An optical imaging lens, in order from an object side to an image side along an optical axis, comprising: a first lens assembly comprising, in order from the object side to the image side along the optical axis, a first lens having negative refractive power, a second lens that is a biconcave lens having negative refractive power, and a third lens that is a biconvex lens having positive refractive power, wherein an object-side surface of the first lens is a convex surface toward the object side, and an image-side surface of the first lens is a concave surface toward the image side; an object-side surface of the second lens and/or an image-side surface of the second lens are/is an aspheric surface;an aperture;a second lens assembly comprising, in order from the object side to the image side along the optical axis, a fourth lens that is a biconvex lens having positive refractive power, a fifth lens that is a biconvex lens having negative refractive power, a sixth lens that is a biconcave lens having negative refractive power, and a seventh lens that is a biconvex lens having positive refractive power, wherein an object-side surface of the sixth lens and an image-side surface of the fifth lens are adhered to form a compound lens having negative refractive power; an object-side surface of the seventh lens and/or an image-side surface of the seventh lens are/is an aspheric surface;wherein the optical imaging lens satisfies: 0.35<F/fg2<0.5; F is a focal length of the optical imaging lens and fg2 is a focal length of the second lens assembly.
14. The optical imaging lens as claimed in claim 13, wherein the optical imaging lens satisfies: -0.65<F/f1<-0.45, wherein f1 is a focal length of the first lens.
15. The optical imaging lens as claimed in claim 13, wherein the optical imaging lens satisfies: -0.25<F/f2<-0.1, wherein f2 is a focal length of the second lens.
16. The optical imaging lens as claimed in claim 13, wherein the optical imaging lens satisfies: 0.25<F/f3<0.42, wherein f3 is a focal length of the third lens.
17. The optical imaging lens as claimed in claim 13, wherein the optical imaging lens satisfies: 0.25<F/f4<0.45, wherein f4 is a focal length of the fourth lens.
18. The optical imaging lens as claimed in claim 13, wherein the optical imaging lens satisfies: -0.3<F/f56<-0.05, wherein f56 is a focal length of the compound lens formed by adhering the fifth lens and the sixth lens.
19. The optical imaging lens as claimed in claims 18, wherein the optical imaging lens satisfies: -0.1<F/f5<0.1, wherein f5 is a focal length of the fifth lens.
20. The optical imaging lens as claimed in claims 18, wherein the optical imaging lens satisfies: -0.45<F/f6<-0.25, wherein f6 is a focal length of the sixth lens.
21. The optical imaging lens as claimed in claims 13, wherein the optical imaging lens satisfies: 0.1<F/f7<0.35, wherein f7 is a focal length of the seventh lens.
22. The optical imaging lens as claimed in claims 13, wherein both of the object-side surface and the image-side surface of the second lens are aspheric surfaces.
23. The optical imaging lens as claimed in claims 13, wherein both of the object-side surface and the image-side surface of the fourth lens are aspheric surfaces.
24. The optical imaging lens as claimed in claims 13, wherein both of the object-side surface and the image-side surface of the seventh lens are aspheric surfaces.

Priority Claims (1)

Number	Date	Country	Kind
111105752	Feb 2022	TW	national

OPTICAL IMAGING LENS

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Publication Number

Date Filed

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Original Assignees

CPC

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Abstract

Description

Claims

Priority Claims (1)