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 and low distortion.

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 a first optical assembly with positive refractive power. The second lens assembly includes, in order along the optical axis Z from the object side to the image side, a second optical assembly with refractive power, a third optical assembly with positive refractive power, a fourth optical assembly with negative refractive power, and a fifth optical assembly with refractive power. Three of the first optical assembly, the second optical assembly, the third optical assembly, the fourth optical assembly, and the fifth optical assembly include a compound lens formed by adhering at least two lenses, while the others are single lens.

The present invention further provides an optical imaging lens, in order from an object side to an image side along an optical axis, includes a first lens having positive refractive power, an aperture, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having positive refractive power, a sixth lens having negative refractive power, a seventh lens having negative refractive power, and an eighth lens having positive refractive power. An object-side surface of the first lens is a convex surface, and an image-side surface of the first lens is a concave surface. The second lens is a biconcave lens. The third lens is a biconvex lens. An object-side surface of the third lens and an image-side surface of the second lens are adhered to form a compound lens. An object-side surface of the fourth lens is a convex surface, and the object-side surface of the fourth lens and/or an image-side surface of the fourth lens are/is an aspheric surface. The fifth lens is a biconvex lens. The sixth lens is a biconcave lens. An object-side surface of the sixth lens and an image-side surface of the fifth lens are adhered to form a compound lens with negative refractive power. The seventh lens is a biconcave lens. The eighth lens is a biconvex lens. An object-side surface of the eighth lens and an image-side surface of the seventh lens are adhered to form a compound lens.

With the aforementioned design, three of the first optical assembly, the second optical assembly, the third optical assembly, the fourth optical assembly, and the fifth optical assembly are a compound lens formed by adhering at least two lenses, thereby effectively improving a chromatic aberration of the optical imaging lens. In addition, the arrangement of the refractive powers and the conditions of the optical imaging lens of the present invention could achieve 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 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 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 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 a first optical assembly C1, and the second lens assembly G2 includes, in order along the optical axis Z from the object side to the image side, a second optical assembly C2, a third optical assembly C3, a fourth optical assembly C4, and a fifth optical assembly C5, wherein three of the first optical assembly, the second optical assembly, the third optical assembly, the fourth optical assembly, and the fifth optical assembly include a compound lens with at least two lenses that are adhered, while the others are single lens.

The first optical assembly C1 has positive refractive power. In the current embodiment, the first optical assembly C1 is a single lens that includes a first lens L1, wherein the first lens L1 is a positive meniscus; 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 that is arc-shaped.

The second optical assembly C2 has refractive power. In the current embodiment, the second optical assembly C2 has positive refractive power and is a compound lens formed by adhering a second lens L2 and a third lens L3, which could effectively improve a chromatic aberration of the optical imaging lens 100. As shown in FIG. 1A, the second lens L2 is a biconcave lens with negative refractive power (i.e., both of an object-side surface S3 of the second lens L2 and an image-side surface S4 of the second lens L2 are concave surfaces). The aperture ST is disposed between the first lens L1 and the second lens L2. The third lens L3 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). The object-side surface S5 of the third lens L3 and the image-side surface S4 of the second lens L2 are adhered and form a same surface.

The third optical assembly C3 has positive refractive power. In the current embodiment, the third optical assembly C3 is a single lens that includes a fourth lens L4, wherein the fourth lens L4 is a positive meniscus. As shown in FIG. 1A, an object-side surface S7 of the fourth lens L4 is convex toward the object side in an arc shape, and an image-side surface S8 of the fourth lens L4 is recessed toward the image side. 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. In the current embodiment, both of the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric surfaces.

The fourth optical assembly C4 has negative refractive power. In the current embodiment, the fourth optical assembly C4 is a compound lens formed by adhering a fifth lens L5 and a sixth lens L6, which could effectively improve a chromatic aberration of the optical imaging lens 100. As shown in FIG. 1A, 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 positive refractive power. The sixth lens L6 is a biconcave lens with negative refractive power (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), wherein a part of a surface of the sixth lens L6 toward the image side is recessed to form the image-side surface S12, and the optical axis Z passes through the object-side surface S11 and the image-side surface S12 of the sixth lens L6. The object-side surface S11 of the sixth lens L6 and the image-side surface S10 of the fifth lens L5 are adhered and form a same surface.

The fifth optical assembly C5 has positive refractive power. In the current embodiment, the fifth optical assembly C5 is a compound lens formed by adhering a seventh lens L7 and an eighth lens L8, which could effectively improve a chromatic aberration of the optical imaging lens 100. As shown in FIG. 1A, the seventh lens L7 is a biconcave lens with negative refractive power (i.e., both of an object-side surface S13 of the seventh lens L7 and an image-side surface S14 of the seventh lens L7 are concave surfaces), wherein a part of a surface of the seventh lens L7 toward the object side is recessed to form the object-side surface S13, and the optical axis Z passes through the object-side surface S13 and the image-side surface S14 of the seventh lens L7. The eighth lens L8 is a biconvex lens (i.e., both of an object-side surface S15 of the eighth lens L8 and an image-side surface S16 of the eighth lens L8 are convex surfaces) with positive refractive power. The object-side surface S15 of the eighth lens L8 and the image-side surface S14 of the seventh lens L7 are adhered and form a same surface.

Additionally, the optical imaging lens 100 further includes an infrared filter L9 and a protective glass L10, wherein the infrared filter L9 is disposed between the eighth lens L8 and the protective glass L10 and is closer to the image-side surface S16 of the eighth lens L8 than the protective glass L10. The protective glass L10 for protecting the infrared filter L9 is disposed between the infrared filter L9 and an image plane Im of the optical imaging lens 100 and is closer to the image plane Im than the infrared filter L9.

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<f1/F<2; (1)

−10<f23/F<22;−2.5<f2/F<−1;1.2<f3/F<3; (2)

1<f4/F<5; (3)

−4<f56/F<−1;1<f5/F<1.5;−1<f6/F<−0.3; (4)

−1.5<f7/F<−0.5;0.1<f8/F<2; (5)

1.3<fg2/F<2.5; (6)

wherein F is a focal length of the optical imaging lens 100; f1 is a focal length of the first lens L1 of the first optical assembly C1; f2 is a focal length of the second lens L2 of the second optical assembly C2; f3 is a focal length of the third lens L3 of the second optical assembly C2; f23 is a focal length of the second optical assembly C2; f4 is a focal length of the fourth lens L4 of the third optical assembly C3; f5 is a focal length of the fifth lens L5 of the fourth optical assembly C4; f6 is a focal length of the sixth lens L6 of the fourth optical assembly C4; f56 is a focal length of the fourth optical assembly C4; f7 is a focal length of the seventh lens L7 of the fifth optical assembly C5; f8 is a focal length of the eighth lens L8 of the fifth optical assembly C5; f78 is a focal length of the fifth optical assembly C5; fg2 is a focal length of a 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 (HFOV), 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, a total length (TTL) of the optical imaging lens 100 (i.e., a distance on the optical axis Z from the object-side surface of the first lens to the image plane), the focal length (cemented focal length) of the second optical assembly C2, and the focal length (cemented focal length) of the fourth optical assembly C4, and the focal length (cemented focal length) of the fifth optical assembly C5, 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 = 24 mm; Fno = 2; HFOV = 20 deg; TTL = 35 mm

Cemented

Focal
focal

Surface
R(mm)
D(mm)
Nd
Vd
length
length
Note

S1
13.9
2.74
1.74
49.3
26.65

L1

S2
42.3
0.52
1.55

ST
Infinity
1.65

ST

S3
−27.97
4.5
1.55
45.8
−50.80
231
L2

S4, S5
9.15
4.46
1.5
81.6
47.08

L3

S6
−18.8
1.73

S7
26.7
3.54
1.81
40.9
53.70

L4

S8
64.8
0.303

S9
19.65
3.92
1.7
56.1
28.10
−25.85
L5

S10, S11
−25
1.62
1.74
32.3
−12.00

L6

S12
9.05
3

S13
−9
0.8
1.59
35.4
−15.10
31.08
L7

S14, S15
19
2.96
2
29.1
11.27

L8

S16
−14.55
0.1

S17
Infinity
0.4
1.52
64.2

Infrared

filter L9

S18
Infinity
2.27

S19
Infinity
0.4
1.52
64.2

Protective

glass L10

S20
Infinity
0.226

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 24 mm, the Fno is 2, the HFOV is 24 degrees, and the TTL is 35 mm, wherein f1=26.65 mm; f2=−50.8 mm; f3=47.08 mm; f4=53.7 mm; f5=28.1 mm; f6=−12.0 mm; f7=−15.1 mm; f8=11.27 mm; f23=231 mm; f56=−25.85 mm; f78=31.08 mm; fg2=47.68 mm.

Additionally, based on the above detailed parameters, detailed values of the aforementioned conditional formula in the first embodiment are as follows: f1/F=1.11; f23/F=9.61; f2/F=−2.11; f3/F=1.96; f4/F=2.23; f56/F=−1.08; f5/F=1.17; f6/F=−0.5; f7/F=−0.63; f8/F=0.47; fg2/F=1.98.

With the aforementioned design, the first optical assembly C1 to the fifth optical assembly C5 satisfy the aforementioned conditions (1) to (6) of the optical imaging lens 100.

Moreover, an aspheric surface contour shape Z of each of the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4 of the optical imaging lens 100 according to the first embodiment could be obtained by following formula:

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

- 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 S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4 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:

TABLE 2

Surface
S7
S8

k
0
0

A4
−7.4000E−05
−1.7000E−05

A6
−1.7000E−05
9.1500E−07

A8
5.2000E−10
−2.0000E−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 a diagram showing the longitudinal spherical aberration according to the first embodiment; FIG. 1C is a diagram showing the lateral 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 a first optical assembly C1, and the second lens assembly G2 includes, in order along the optical axis Z from the object side to the image side, a second optical assembly C2, a third optical assembly C3, a fourth optical assembly C4, and a fifth optical assembly C5.

The first optical assembly C1 has positive refractive power. In the current embodiment, the first optical assembly C1 is a single lens that includes a first lens L1, wherein the first lens L1 is a biconvex lens (i.e., both of an object-side surface S1 of the first lens L1 and an image-side surface S2 of the first lens L1 are convex surfaces).

The second optical assembly C2 has refractive power. In the current embodiment, the second optical assembly C2 has positive refractive power and is a compound lens formed by adhering a second lens L2 and a third lens L3, which could effectively improve a chromatic aberration of the optical imaging lens 100. As shown in FIG. 2A, the second lens L2 is a biconcave lens with negative refractive power (i.e., both of an object-side surface S3 of the second lens L2 and an image-side surface S4 of the second lens L2 are concave surfaces), wherein a part of a surface of the second lens L2 toward the object side is recessed to form the object-side surface S3, and the optical axis Z passes through the object-side surface S3 and the image-side surface S4 of the second lens L2. The third lens L3 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). The object-side surface S5 of the third lens L3 and the image-side surface S4 of the second lens L2 are adhered and form a same surface.

The third optical assembly C3 has positive refractive power. In the current embodiment, the third optical assembly C3 is a single lens that includes a fourth lens L4, wherein 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). 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, both of the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric surfaces.

The fourth optical assembly C4 has negative refractive power. In the current embodiment, the fourth optical assembly C4 is a compound lens formed by adhering a fifth lens L5 and a sixth lens L6, which could effectively improve a chromatic aberration of the optical imaging lens 200. As shown in FIG. 2A, 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 positive refractive power. The sixth lens L6 is a biconcave lens with negative refractive power (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), wherein a part of a surface of the sixth lens L6 toward the image side is recessed to form the image-side surface S12, and the optical axis Z passes through the object-side surface S11 and the image-side surface S12 of the sixth lens L6. The object-side surface S11 of the sixth lens L6 and the image-side surface S10 of the fifth lens L5 are adhered and form a same surface.

The fifth optical assembly C5 has refractive power. In the current embodiment, the fifth optical assembly C5 has negative refractive power and is a compound lens formed by adhering a seventh lens L7 and an eighth lens L8, which could effectively improve a chromatic aberration of the optical imaging lens 200. As shown in FIG. 2A, the seventh lens L7 is a biconcave lens with negative refractive power (i.e., both of an object-side surface S13 of the seventh lens L7 and an image-side surface S14 of the seventh lens L7 are concave surfaces). The eighth lens L8 is a biconvex lens (i.e., both of an object-side surface S15 of the eighth lens L8 and an image-side surface S16 of the eighth lens L8 are convex surfaces) with positive refractive power. The object-side surface S15 of the eighth lens L8 and the image-side surface S14 of the seventh lens L7 are adhered and form a same surface.

Additionally, the optical imaging lens 200 further includes an infrared filter L9 and a protective glass L10, wherein the infrared filter L9 is disposed between the eighth lens L8 and the protective glass L10 and is closer to the image-side surface S16 of the eighth lens L8 than the protective glass L10, thereby filtering out excess infrared rays in an image light passing through the optical imaging lens 200 to improve imaging quality. The protective glass L10 for protecting the infrared filter L9 is disposed between the infrared filter L9 and an image plane Im of the optical imaging lens 200.

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<f1/F<2; (1)

−10<f23/F<22;−2.5<f2/F<−1;1.2<f3/F<3; (2)

1<f4/F<5; (3)

−4<f56/F<−1;1<f5/F<1.5;−1<f6/F<−0.3; (4)

−1.5<f7/F<−0.5;0.1<f8/F<2; (5)

1.3<fg2/F<2.5; (6)

wherein F is a focal length of the optical imaging lens 200; f1 is a focal length of the first lens L1 of the first optical assembly C1; f2 is a focal length of the second lens L2 of the second optical assembly C2; f3 is a focal length of the third lens L3 of the second optical assembly C2; f23 is a focal length of the second optical assembly C2; f4 is a focal length of the fourth lens L4 of the third optical assembly C3; f5 is a focal length of the fifth lens L5 of the fourth optical assembly C4; f6 is a focal length of the sixth lens L6 of the fourth optical assembly C4; f56 is a focal length of the fourth optical assembly C4; f7 is a focal length of the seventh lens L7 of the fifth optical assembly C5; f8 is a focal length of the eighth lens L8 of the fifth optical assembly C5; f78 is a focal length of the fifth optical assembly C5; fg2 is a focal length of a second lens assembly G2.

Parameters of the optical imaging lens 200 of the second embodiment of the present invention are listed in following Table 3, 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 (HFOV), 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, a total length (TTL) of the optical imaging lens 200 (i.e., a distance on the optical axis Z from the object-side surface of the first lens to the image plane), the focal length (cemented focal length) of the second optical assembly C2, and the focal length (cemented focal length) of the fourth optical assembly C4, 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 3

F = 17.7 mm; Fno = 2; HFOV = 30 deg; TTL = 34 mm

Cemented

Focal
focal

Surface
R(mm)
D(mm)
Nd
Vd
length
length
Note

S1
24.1
2.98
1.74
49.4
32.30

L1

S2
−101.6
0.52

ST
Infinity
1.64

ST

S3
−11.9
5.71
1.55
45.8
−21.62
374.138
L2

S4, S5
18
3.03
1.5
81.6
25.97

L3

S6
−12.1
0.1

S7
67.4
3.54
1.81
40.9
83.00

L4

S8
−35
0.1

S9
17
4.08
1.7
56.4
24.32
−62.60
L5

S10, S11
−14.63
1.62
1.74
32.3
−15.15

L6

S12
11.8
2.4

S13
−13
0.8
1.59
35.3
−21.82
−87.75
L7

S14, S15
11.9
3.33
2
29.1
30.00

L8

S16
780
0.1

S17
Infinity
0.4
1.52
64.2

Infrared

filter L9

S18
Infinity
1.31

S19
Infinity
0.4
1.52
64.2

Protective

glass L10

S20
Infinity
1.92

Im
Infinity

Im

It can be seen from Table 3 that, in the second embodiment, the focal length (F) of the optical imaging lens 200 is 17.7 mm, the Fno is 2, the HFOV is 30 degrees, and the TTL is 34 mm, wherein f1=−32.3 mm; f2=−21.62 mm; f3=25.97 mm; f4=83.0 mm; f5=24.32 mm; f6=−15.15 mm; f7=−21.82 mm; f8=30 mm; f23=374.138 mm; f56=−62.6 mm; f78=−87.75 mm; fg2=37.21 mm.

Additionally, based on the above detailed parameters, detailed values of the aforementioned conditional formula in the second embodiment are as follows: f1/F=1.83; f23/F=21.14; f2/F=−1.22; f3/F=1.47; f4/F=4.69; f56/F=−3.54; f5/F=1.37; f6/F=−0.86; f7/F=−1.23; f8/F=1.69; fg2/F=2.1.

With the aforementioned design, the first optical assembly C1 to the fifth optical assembly C5 satisfy the aforementioned conditions (1) to (6) of the optical imaging lens 200.

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

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

- 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 S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4 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 4:

TABLE 4

Surface
S7
S8

k
0
0

A4
−9.3000E−05
−6.5300E−05

A6
1.8000E−06
4.1200E−07

A8
−1.6000E−07
−7.7000E−08

A10
4.9000E−09
2.6000E−09

A12
−5.8500E−11
−3.2000E−11

A14
0
0

A16
0
0

Taking optical simulation data to verify the imaging quality of the optical imaging lens 200, wherein FIG. 2B a diagram showing the longitudinal spherical aberration according to the second embodiment; FIG. 2C is a diagram showing the lateral 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 a first optical assembly C1, and the second lens assembly G2 includes, in order along the optical axis Z from the object side to the image side, a second optical assembly C2, a third optical assembly C3, a fourth optical assembly C4, and a fifth optical assembly C5.

The second optical assembly C2 has refractive power. In the current embodiment, the second optical assembly C2 has negative refractive power and is a compound lens formed by adhering a second lens L2 and a third lens L3, which could effectively improve a chromatic aberration of the optical imaging lens 100. As shown in FIG. 3A, the second lens L2 is a biconcave lens with negative refractive power (i.e., both of an object-side surface S3 of the second lens L2 and an image-side surface S4 of the second lens L2 are concave surfaces), and the optical axis Z passes through the object-side surface S3 and the image-side surface S4 of the second lens L2. The third lens L3 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). The object-side surface S5 of the third lens L3 and the image-side surface S4 of the second lens L2 are adhered and form a same surface.

The third optical assembly C3 has positive refractive power. In the current embodiment, the third optical assembly C3 is a single lens that includes a fourth lens L4, wherein 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). 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. 3A, both of the object-side surface S7 and the image-side surface S8 of the fourth lens L4 are aspheric surfaces.

The fourth optical assembly C4 has negative refractive power. In the current embodiment, the fourth optical assembly C4 is a compound lens formed by adhering a fifth lens L5 and a sixth lens L6, which could effectively improve a chromatic aberration of the optical imaging lens 300. As shown in FIG. 3A, 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 positive refractive power. The sixth lens L6 is a biconcave lens with negative refractive power (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), and the optical axis Z passes through the object-side surface S11 and the image-side surface S12 of the sixth lens L6. The object-side surface S11 of the sixth lens L6 and the image-side surface S10 of the fifth lens L5 are adhered and form a same surface.

The fifth optical assembly C5 has refractive power. In the current embodiment, the fifth optical assembly C5 has positive refractive power and is a compound lens formed by adhering a seventh lens L7 and an eighth lens L8, which could effectively improve a chromatic aberration of the optical imaging lens 300. As shown in FIG. 3A, the seventh lens L7 is a biconcave lens with negative refractive power (i.e., both of an object-side surface S13 of the seventh lens L7 and an image-side surface S14 of the seventh lens L7 are concave surfaces), wherein a part of a surface of the seventh lens L7 toward the object side is recessed to form the object-side surface S13, and the optical axis Z passes through the object-side surface S13 and the image-side surface S14 of the seventh lens L7. The eighth lens L8 is a biconvex lens (i.e., both of an object-side surface S15 of the eighth lens L8 and an image-side surface S16 of the eighth lens L8 are convex surfaces) with positive refractive power. The object-side surface S15 of the eighth lens L8 and the image-side surface S14 of the seventh lens L7 are adhered and form a same surface.

Additionally, the optical imaging lens 300 further includes an infrared filter L9 and a protective glass L10, wherein the infrared filter L9 is disposed between the eighth lens L8 and the protective glass L10 and is closer to the image-side surface S16 of the eighth lens L8 than the protective glass L10, thereby filtering out excess infrared rays in an image light passing through the optical imaging lens 300 to improve imaging quality. The protective glass L10 for protecting the infrared filter L9 is disposed between the infrared filter L9 and an image plane Im of the optical imaging lens 300 and is closer to the image plane Im than the infrared filter L9.

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<f1/F<2; (1)

−10<f23/F<22;−2.5<f2/F<−1;1.2<f3/F<3; (2)

1<f4/F<5; (3)

−4<f56/F<−1;1<f5/F<1.5;−1<f6/F<−0.3; (4)

−1.5<f7/F<−0.5;0.1<f8/F<2; (5)

1.3<fg2/F<2.5; (6)

wherein F is a focal length of the optical imaging lens 300; f1 is a focal length of the first lens L1 of the first optical assembly C1; f2 is a focal length of the second lens L2 of the second optical assembly C2; f3 is a focal length of the third lens L3 of the second optical assembly C2; f23 is a focal length of the second optical assembly C2; f4 is a focal length of the fourth lens L4 of the third optical assembly C3; f5 is a focal length of the fifth lens L5 of the fourth optical assembly C4; f6 is a focal length of the sixth lens L6 of the fourth optical assembly C4; f56 is a focal length of the fourth optical assembly C4; f7 is a focal length of the seventh lens L7 of the fifth optical assembly C5; f8 is a focal length of the eighth lens L8 of the fifth optical assembly C5; f78 is a focal length of the fifth optical assembly C5; fg2 is a focal length of a second lens assembly G2.

Parameters of the optical imaging lens 300 of the third embodiment of the present invention are listed in following Table 5, 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 (HFOV), 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, a total length (TTL) of the optical imaging lens 100 (i.e., a distance on the optical axis Z from the object-side surface of the first lens to the image plane), the focal length (cemented focal length) of the second optical assembly C2, and the focal length (cemented focal length) of the fourth optical assembly C4, 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 = 21.07 mm; Fno = 2; HFOV = 23.3 deg; TTL = 34.4 mm

Cemented

Focal
focal

Surface
R(mm)
D(mm)
Nd
Vd
length
length
Note

S1
14.7
2.74
1.74
49.3
30.15

L1

S2
39.07
0.52

ST
Infinity
1.64

ST

S3
−20.93
4.5
1.55
45.8
−38.03
−195.262
L2

S4, S5
10.83
4.46
1.5
81.5
55.46

L3

S6
−22.11
0.1

S7
40.02
3.54
1.81
40.9
24.97

L4

S8
−39.45
0.1

S9
16
3.92
1.7
55.5
22.89
−43.25
L5

S10, S11
−16
1.62
1.74
32.3
−12.87

L6

S12
9.92
3.5

S13
−7.55
1.4
1.59
35.3
−12.67
96.254
L7

S14, S15
36.6
2.61
2
29.1
12.97

L8

S16
−15.07
0.1

S17
Infinity
0.4
1.52
64.2

Infrared

filter L9

S18
Infinity
2.27

S19
Infinity
0.4
1.52
64.2

Protective

glass L10

S20
Infinity
0.615

Im
Infinity

Im

It can be seen from Table 5 that, in the current embodiment, the focal length F of the optical imaging lens 300 is 21.07 mm, the Fno is 2, the HFOV is 22.3 degrees, and the TTL is 34 mm, wherein f1=30.15 mm; f2=−38.03 mm; f3=55.46 mm; f4=24.97 mm; f5=22.89 mm; f6=−12.87 mm; f7=−12.67 mm; f8=12.97 mm; f23=−195.262 mm; f56=−43.25 mm; f78=96.254 mm; fg2=33.382 mm.

Additionally, based on the above detailed parameters, detailed values of the aforementioned conditional formula in the third embodiment are as follows: f1/F=1.43; f23/F=−9.27; f2/F=−1.81; f3/F=2.63; f4/F=1.18; f56/F=−2.05; f5/F=1.09; f6/F=−0.61; f7/F=−0.6; f8/F=0.62; fg2/F=1.58.

With the aforementioned design, the first optical assembly C1 to the fifth optical assembly C5 satisfy the aforementioned conditions (1) to (6) of the optical imaging lens 300.

Moreover, an aspheric surface contour shape Z of each of the object-side surface S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4 of the optical imaging lens 300 according to the third embodiment could be obtained by following formula:

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

- 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 S7 of the fourth lens L4, and the image-side surface S8 of the fourth lens L4 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 6:

TABLE 4

Surface
S7
S8

k
0
0

A4
−7.6600E−05
−6.8100E−05

A6
−6.4700E−07
−4.5400E−07

A8
0
0

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 a diagram showing the longitudinal spherical aberration according to the third embodiment; FIG. 3C is a diagram showing the lateral 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 a first optical assembly, wherein the first optical assembly has positive refractive power;an aperture;a second lens assembly comprising, in order along the optical axis Z from the object side to the image side, a second optical assembly, a third optical assembly, a fourth optical assembly, and a fifth optical assembly; the second optical assembly has refractive power; the third optical assembly has positive refractive power; the fourth optical assembly has negative refractive power; the fifth optical assembly has refractive power;wherein three of the first optical assembly, the second optical assembly, the third optical assembly, the fourth optical assembly, and the fifth optical assembly comprise a compound lens formed by adhering at least two lenses, while the others are single lens.
2. The optical imaging lens as claimed in claim 1, wherein the first optical assembly is a single lens that comprises a first lens; the second optical assembly is a compound lens that comprises a second lens and a third lens; the third optical assembly is a single lens that comprises a fourth lens; the fourth optical assembly is a compound lens that comprises a fifth lens and a sixth lens; the fifth optical assembly is a compound lens that comprises a seventh lens and an eighth lens.
3. The optical imaging lens as claimed in claim 2, wherein the optical imaging lens satisfies: 1<f1/F<2, wherein F is a focal length of the optical imaging lens; f1 is a focal length of the first lens.
4. The optical imaging lens as claimed in claim 2, wherein the optical imaging lens satisfies: −10<f23/F<22, wherein F is a focal length of the optical imaging lens; f23 is a focal length of the second optical assembly.
5. The optical imaging lens as claimed in claim 4, wherein the optical imaging lens satisfies: −2.5<f2/F<−1, wherein F is a focal length of the optical imaging lens; f2 is a focal length of the second lens.
6. The optical imaging lens as claimed in claim 4, wherein the optical imaging lens satisfies: 1.2<f3/F<3, wherein F is a focal length of the optical imaging lens; f3 is a focal length of the third optical assembly.
7. The optical imaging lens as claimed in claim 2, wherein the optical imaging lens satisfies: 1<f4/F<5, wherein F is a focal length of the optical imaging lens; f4 is a focal length of the fourth lens.
8. The optical imaging lens as claimed in claim 2, wherein the optical imaging lens satisfies: −4<f56/F<−1, wherein F is a focal length of the optical imaging lens; f56 is a focal length of the fourth optical assembly.
9. The optical imaging lens as claimed in claim 8, wherein the optical imaging lens satisfies: 1<f5/F<1.5, wherein F is a focal length of the optical imaging lens; f5 is a focal length of the fifth lens.
10. The optical imaging lens as claimed in claim 8, wherein the optical imaging lens satisfies: −1<f6/F<−0.3, wherein F is a focal length of the optical imaging lens; f6 is a focal length of the sixth lens.
11. The optical imaging lens as claimed in claim 2, wherein the optical imaging lens satisfies: −1.5<f7/F<−0.5, wherein F is a focal length of the optical imaging lens; f7 is a focal length of the seventh lens.
12. The optical imaging lens as claimed in claim 2, wherein the optical imaging lens satisfies: 0.1<f8/F<2, wherein F is a focal length of the optical imaging lens; f8 is a focal length of the eighth lens.
13. The optical imaging lens as claimed in claim 1, wherein the optical imaging lens satisfies: 1.3<fg2/F<2.5, wherein F is a focal length of the optical imaging lens; fg2 is a focal length of the second lens assembly.
14. An optical imaging lens, in order from an object side to an image side along an optical axis, comprising: a first lens having positive refractive power, wherein an object-side surface of the first lens is a convex surface;an aperture;a second lens, which is a biconcave lens with negative refractive power;a third lens, which is a biconvex lens with positive refractive power, wherein an object-side surface of the third lens and an image-side surface of the second lens are adhered to form a compound lens;a fourth lens having positive refractive power, wherein an object-side surface of the fourth lens is a convex surface; the object-side surface of the fourth lens and/or an image-side surface of the fourth lens are/is an aspheric surface;a fifth lens, which is a biconvex lens with positive refractive power;a sixth lens, which is a biconcave lens with negative 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 with negative refractive power;a seventh lens, which is a biconcave lens with negative refractive power; andan eighth lens, which is a biconvex lens with positive refractive power, wherein an object-side surface of the eighth lens and an image-side surface of the seventh lens are adhered to form a compound lens.
15. The optical imaging lens as claimed in claim 14, wherein both of the object-side surface and the image-side surface of the fourth lens are aspheric surfaces.
16. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: 1<f1/F<2, wherein F is a focal length of the optical imaging lens; f1 is a focal length of the first lens.
17. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: −10<f23/F<22, wherein F is a focal length of the optical imaging lens; f23 is a focal length of the compound lens formed by adhering the second lens and the third lens.
18. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: −2.5<f2/F<−1, wherein F is a focal length of the optical imaging lens; f2 is a focal length of the second lens.
19. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: 1.2<f3/F<3, wherein F is a focal length of the optical imaging lens; f3 is a focal length of the third lens.
20. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: 1<f4/F<5, wherein F is a focal length of the optical imaging lens; f4 is a focal length of the fourth lens.
21. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: −4<f56/F<−1, wherein F is a focal length of the optical imaging lens; f56 is a focal length of the compound lens formed by adhering the fifth lens and the sixth lens.
22. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: 1<f5/F<1.5, wherein F is a focal length of the optical imaging lens; f5 is a focal length of the fifth lens.
23. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: −1<f6/F<−0.3, wherein F is a focal length of the optical imaging lens; f6 is a focal length of the sixth lens.
24. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: −1.5<f7/F<−0.5, wherein F is a focal length of the optical imaging lens; f7 is a focal length of the seventh lens.
25. The optical imaging lens as claimed in claim 14, wherein the optical imaging lens satisfies: 0.1<f8/F<2, wherein F is a focal length of the optical imaging lens; f8 is a focal length of the eighth lens.

Priority Claims (1)

Number	Date	Country	Kind
110139510	Oct 2021	TW	national

OPTICAL IMAGING LENS

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Priority Claims (1)