CN115113380A

CN115113380A - Optical lens

Info

Publication number: CN115113380A
Application number: CN202211050532.7A
Authority: CN
Inventors: 章彬炜; 肖国亮; 曾昊杰
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2022-08-30
Filing date: 2022-08-30
Publication date: 2022-09-27
Anticipated expiration: 2042-08-30
Also published as: CN115113380B

Abstract

The invention discloses an optical lens, which comprises the following components in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a convex object-side surface and a concave image-side surface; a second lens element having a negative refractive power, the object-side surface of the second lens element being concave, and the image-side surface of the second lens element being concave; a third lens with positive focal power, wherein the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; a diaphragm; a fourth lens with positive focal power, wherein the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; a fifth lens element with negative optical power, having a convex object-side surface and a concave image-side surface at a paraxial region; a sixth lens with positive focal power, wherein the object-side surface of the sixth lens is a convex surface, and the image-side surface of the sixth lens is a convex surface; a seventh lens having a negative optical power, an image-side surface of which is concave at a paraxial region; the first lens to the seventh lens at least comprise a spherical lens and an aspherical lens. The optical lens has the advantages of large field angle, high pixel and small distortion.

Description

Optical lens

Technical Field

The invention relates to the technical field of optical lenses, in particular to an optical lens.

Background

With the rapid development of image and computer vision technologies, more and more technologies are applied to the automobile field, and vehicle-mounted looking-around systems are also applied to various vehicles more and more. For safety reasons, the vehicle-mounted looking-around system needs to increase the visual field of a driver and simultaneously sense 360-degree all-round environment. The cooperation of a plurality of visual sensors is needed, and then a whole set of video images around the whole vehicle are formed and displayed on a screen of a center console through video synthesis processing, so that a driver can clearly check whether obstacles exist around the vehicle, the operation of backing, parking and the like of the driver is facilitated, and the safety risk is reduced.

The wide-angle lens has the characteristic of large field angle, and can acquire more information under the same condition, so the wide-angle lens is widely applied to a vehicle-mounted all-round system. However, the existing wide-angle lens applied to the vehicle-mounted system generally has the following problems: the lens has low pixels, insufficient resolution and more noise points; due to the wide-angle design, the imaging effect of the marginal field of view is slightly poor; the vehicle-mounted reliability requirement is difficult to meet, the requirement on the environment is severe, and the service life is relatively short.

Disclosure of Invention

Accordingly, an object of the present invention is to provide an optical lens having advantages of a large angle of view, high pixels, and small distortion.

The invention provides an optical lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: the lens comprises a first lens with negative focal power, a second lens and a third lens, wherein the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens is provided with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a concave surface; the lens comprises a third lens with positive focal power, wherein the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; a diaphragm; the fourth lens is provided with positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; a fifth lens element having a negative optical power, an object-side surface of the fifth lens element being convex at a paraxial region and an image-side surface of the fifth lens element being concave; the lens comprises a sixth lens with positive focal power, wherein the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface; a seventh lens having a negative optical power, an image side surface of the seventh lens being concave at a paraxial region; wherein the first lens to the seventh lens at least comprise a spherical lens and an aspherical lens.

Compared with the prior art, the optical lens provided by the invention adopts the combination of seven spherical lenses with specific focal power and the aspheric lens, and has good imaging quality through specific surface shape collocation and reasonable focal power distribution, and can be matched with an imaging chip with higher pixels to realize high-definition imaging; meanwhile, the size of the lens aperture is reasonably configured, so that the light incoming amount of the system can be enlarged, and the depth of field during shooting can be reduced; through different lens combinations, the vehicle-mounted all-around vision system has an ultra-large field angle of 210 degrees, achieves the all-around vision effect, and can well meet the use requirements of the vehicle-mounted all-around vision system.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present invention;

FIG. 2 is a graph illustrating f-theta distortion of an optical lens according to a first embodiment of the present invention;

FIG. 3 is a field curvature diagram of an optical lens according to a first embodiment of the present invention;

FIG. 4 is a vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present invention;

FIG. 5 is a schematic structural diagram of an optical lens system according to a second embodiment of the present invention;

FIG. 6 is a graph showing the f-theta distortion of an optical lens according to a second embodiment of the present invention;

FIG. 7 is a field curvature graph of an optical lens according to a second embodiment of the present invention;

FIG. 8 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present invention;

FIG. 9 is a diagram illustrating an optical lens assembly according to a third embodiment of the present invention;

FIG. 10 is a graph showing the f- θ distortion of an optical lens according to a third embodiment of the present invention;

FIG. 11 is a field curvature graph of an optical lens according to a third embodiment of the present invention;

fig. 12 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present invention.

Detailed Description

In order to make the objects, features and advantages of the present invention more comprehensible, embodiments accompanying figures are described in detail below. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.

The invention provides an optical lens, which sequentially comprises the following components from an object side to an imaging surface along an optical axis: the lens comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an optical filter.

The first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

the second lens has negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a concave surface;

the third lens has positive focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface;

the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface;

the fifth lens has negative focal power, the object-side surface of the fifth lens is convex at a paraxial region, and the image-side surface of the fifth lens is concave;

the sixth lens has positive focal power, the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface;

the seventh lens element has a negative optical power, and an image-side surface of the seventh lens element is concave at a paraxial region;

the first lens to the seventh lens at least comprise a spherical lens and an aspherical lens.

The optical lens provided by the invention adopts the reasonable collocation of the seven spherical lenses and the aspheric lenses, so that the image quality can be obviously improved, the aberration can be reduced, the number of lenses of the lens can be reduced, the volume can be reduced, and the balance of high image quality and miniaturization can be better realized.

In some embodiments, the optical lens satisfies the following conditional expression:

0.7mm/rad<f/θ<0.9mm/rad；（1）

100°<θ<110°；（2）

where f denotes an effective focal length of the optical lens, and θ denotes a maximum half field angle of the optical lens. Satisfying above-mentioned conditional expressions (1) and (2), can making optical lens possess great angle of vision, can shoot the scene in the great field of vision scope, still have shorter focal length simultaneously, make the depth of field of camera lens big, can guarantee that the scenery all can clear reappearance on the picture before and after the subject of shooing.

6.5<DM1/f<9；（3）

where DM1 represents the effective diameter of the first lens and f represents the effective focal length of the optical lens. Satisfying the above conditional expression (3), the first lens can have a larger aperture, and can receive light rays in a larger range, thereby greatly improving the field angle of the optical lens.

-6<f2/f<-2；（4）

-5<R21/R22<-1.5；（5）

where f2 denotes a focal length of the second lens, f denotes an effective focal length of the optical lens, R21 denotes a radius of curvature of an object-side surface of the second lens, and R22 denotes a radius of curvature of an image-side surface of the second lens. Satisfying the above conditional expressions (4) and (5), the second lens has a proper negative focal power, which is beneficial to the light entering the system more smoothly, reduces the difficulty of aberration correction, and improves the resolving power of the optical lens.

3.5<f3/f<7；（6）

1<R31/R32<20；（7）

where f3 denotes a focal length of the third lens, f denotes an effective focal length of the optical lens, R31 denotes a radius of curvature of an object-side surface of the third lens, and R32 denotes a radius of curvature of an image-side surface of the third lens. The conditional expressions (6) and (7) are satisfied, and the shape change of the third lens can be slowed down by adjusting the focal length and the surface shape of the third lens, so that the system sensitivity is reduced, the formability of the lens is improved, and the manufacturing yield is improved.

1<f4/f<2；（8）

where f4 denotes a focal length of the fourth lens, and f denotes an effective focal length of the optical lens. Satisfy above-mentioned conditional expression (8), through the focus of reasonable setting fourth lens, correction system's that can be better point ball poor colour difference improves the formation of image quality.

-2.5<f5/f<-1；（9）

0.6<R52/f<1.2；（10）

where f5 denotes a focal length of the fifth lens, f denotes an effective focal length of the optical lens, and R52 denotes a radius of curvature of an image side surface of the fifth lens. Satisfying the conditional expressions (9) and (10), the shape change of the fifth lens can be slowed down by adjusting the focal length and the surface shape of the fifth lens, the system sensitivity is reduced, the formability of the lens is improved, and the manufacturing yield is improved.

1<f6/f<2；（11）

-6<R61/R62<-1；（12）

wherein R61 denotes a radius of curvature of an object side surface of the sixth lens, R62 denotes a radius of curvature of an image side surface of the sixth lens, f6 denotes a focal length of the sixth lens, and f denotes an effective focal length of the optical lens. When the conditional expressions (11) and (12) are met, the focal length and the surface shape of the sixth lens can be reasonably controlled, so that the structure of the sixth lens is biconvex, the aberration correction of the optical lens is facilitated, and the imaging quality of the lens is improved.

-5<f7/f<-1；（13）

1<R72/f<60；（14）

where f7 denotes a focal length of the seventh lens, f denotes an effective focal length of the optical lens, and R72 denotes a radius of curvature of an image side surface of the seventh lens. Satisfying the conditional expressions (13) and (14), the seventh lens has a suitable negative focal power and a suitable surface shape, which is beneficial to increasing the imaging area of the optical lens, balancing the aberration of the front lens and improving the overall imaging quality of the optical lens.

Nd1>1.7；（15）

Nd3>1.7；（16）

where Nd1 denotes a refractive index of the first lens, and Nd3 denotes a refractive index of the third lens. The first lens and the third lens are made of materials within a specific refractive index range and are complementary with other plastic lenses, so that the size of the lens is effectively reduced, and the imaging stability of the optical lens in a high-temperature and low-temperature environment is improved.

7<TTL/f<9；（17）

wherein, TTL represents the optical total length of the optical lens, and f represents the effective focal length of the optical lens. Satisfying the conditional expression (17) is advantageous for shortening the overall length of the optical system and realizing miniaturization of the lens.

0.08<BFL/TTL<0.15；（18）

wherein BFL represents the optical back focus of the optical lens, and TTL represents the total length of the optical lens. The condition (18) is satisfied, and the influence on the imaging quality of the optical lens caused by the interference between the lens and the chip due to insufficient back focus can be avoided.

1.5<DM7/DM4<2.2；（19）

wherein DM4 represents an effective diameter of the fourth lens and DM7 represents an effective diameter of the seventh lens. Satisfying the conditional expression (19), the structure of the optical lens can be more compact, and the total length of the lens can be shortened.

-1.5<(R41+R42)/(R41-R42)<-0.5；（20）

wherein R41 denotes a radius of curvature of an object-side surface of the fourth lens, and R42 denotes a radius of curvature of an image-side surface of the fourth lens. The condition (20) is satisfied, the sensitivity of the fourth lens can be reduced, the aberration of the optical system is reduced, and the imaging quality of the optical lens is improved.

1.0<(CT4+CT5+CT6+CT7)/(ET4+ET5+ET6+ET7)<1.2；（21）

wherein CT4 denotes a center thickness of the fourth lens, CT5 denotes a center thickness of the fifth lens, CT6 denotes a center thickness of the sixth lens, CT7 denotes a center thickness of the seventh lens, ET4 denotes an edge thickness of the fourth lens, ET5 denotes an edge thickness of the fifth lens, ET6 denotes an edge thickness of the sixth lens, and ET7 denotes an edge thickness of the seventh lens. When the conditional expression (21) is satisfied, the shapes of the fourth lens, the fifth lens, the sixth lens and the seventh lens can be reasonably limited, the tendency of light deflection is favorably relieved, the aberration of the system is effectively corrected, and the total length of the lens is shortened while high pixels are ensured.

In some embodiments, the first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are plastic aspheric lenses. The use of aspheric lenses has at least three advantages: the lens has better imaging quality; the structure of the lens is more compact; the total optical length of the lens is shorter. In addition, in some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens may also be all glass lenses, or a combination of plastic lenses and glass lenses.

The invention is further illustrated below in the following examples. In various embodiments, the thickness, the curvature radius, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to in the parameter tables of the various embodiments. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the innovative points of the present invention should be construed as being equivalent substitutions and shall be included within the scope of the present invention.

In the embodiments of the present invention, when the lenses in the optical lens are aspheric lenses, the aspheric surface types of the lenses all satisfy the following equation:

wherein z represents the rise of the distance between the aspheric surface and the aspheric surface vertex in the optical axis direction at the position of height h, c is the paraxial curvature of the surface, k is the conic coefficient, A _2i Is the aspheric surface type coefficient of 2i order.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present invention is shown, where the optical lens 100 sequentially includes, from an object side to an image plane S17 along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a filter G1.

The first lens L1 has negative focal power, the object-side surface S1 of the first lens is convex, and the image-side surface S2 of the first lens is concave;

the second lens L2 has negative focal power, the object-side surface S3 of the second lens is concave, and the image-side surface S4 of the second lens is concave;

the third lens L3 has positive focal power, the object-side surface S5 of the third lens is a concave surface, and the image-side surface S6 of the third lens is a convex surface;

the fourth lens L4 has positive focal power, the object-side surface S7 of the fourth lens is convex, and the image-side surface S8 of the fourth lens is convex;

the fifth lens element L5 has negative power, with an object-side surface S9 being convex at paraxial region and an image-side surface S10 being concave;

the sixth lens L6 has positive refractive power, and the object-side surface S11 of the sixth lens is convex, and the image-side surface S12 of the sixth lens is convex;

the seventh lens L7 has a negative power, the object side surface S13 of the seventh lens is concave at the paraxial region, and the image side surface S14 of the seventh lens is concave at the paraxial region;

the object-side surface of the filter G1 is S15, and the image-side surface is S16.

The second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all plastic aspheric lenses, the first lens L1 and the third lens L3 are glass spherical lenses, and glass-plastic mixed lenses are adopted for matching, so that the lens has good thermal stability in high and low temperature environments, and meanwhile, the lens has a small size.

Specifically, the design parameters of each lens of the optical lens 100 provided in this embodiment are shown in table 1.

TABLE 1

In this embodiment, aspheric parameters of each lens in the optical lens 100 are shown in table 2.

TABLE 2

Referring to fig. 2, fig. 3 and fig. 4, a f- θ distortion curve, a field curvature curve and a vertical axis chromatic aberration curve of the optical lens 100 are respectively shown. It can be seen from fig. 2 that the f-theta distortion value is controlled within ± 4%, which indicates that the f-theta distortion of the optical lens 100 is better corrected; it can be seen from fig. 3 that the curvature of field is controlled within ± 0.04 mm, which indicates that the curvature of field of the optical lens 100 is better corrected; it can be seen from fig. 4 that the vertical chromatic aberration of the longest wavelength and the shortest wavelength are controlled within ± 4.2 microns, which indicates that the vertical chromatic aberration of the optical lens 100 is well corrected.

Second embodiment

Referring to fig. 5, a schematic structural diagram of an optical lens 200 according to a second embodiment of the present invention is shown, the optical lens 200 of the present embodiment is substantially the same as the first embodiment, except that an object-side surface S13 of the seventh lens element is a convex surface at a paraxial region, and curvature radii, aspheric coefficients, and thicknesses of the lens surface types are different.

Specifically, the design parameters of the optical lens 200 provided in this embodiment are shown in table 3.

TABLE 3

The aspherical parameters of the respective lenses in the optical lens 200 in the present embodiment are shown in table 4.

TABLE 4

Referring to fig. 6, 7 and 8, a f- θ distortion curve, a field curvature curve and a vertical axis chromatic aberration curve of the optical lens 200 are shown. Wherein, it can be seen from fig. 6 that the f- θ distortion value is controlled within ± 3%, which indicates that the f- θ distortion of the optical lens 200 is better corrected; as can be seen from fig. 7, the curvature of field is controlled within ± 0.03 mm, which indicates that the curvature of field of the optical lens 200 is better corrected; it can be seen from fig. 4 that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 4.5 microns, which indicates that the vertical chromatic aberration of the optical lens 200 is well corrected.

Third embodiment

Referring to fig. 9, a schematic structural diagram of an optical lens 300 according to a third embodiment of the present invention is shown, where the optical lens 300 of the present embodiment is substantially the same as the first embodiment, and mainly differs in the curvature radius, aspheric coefficient, and thickness of each lens surface type.

Specifically, the design parameters of the optical lens 300 provided in this embodiment are shown in table 5.

TABLE 5

In the present embodiment, aspheric parameters of each lens in the optical lens 300 are shown in table 6.

TABLE 6

Referring to fig. 10, 11 and 12, a f- θ distortion curve, a field curvature curve and a vertical axis chromatic aberration curve of the optical lens 300 are respectively shown. Among them, it can be seen from fig. 10 that the f- θ distortion value is controlled within ± 6%, which indicates that the f- θ distortion of the optical lens 300 is better corrected; it can be seen from fig. 11 that the curvature of field is controlled within ± 0.04 mm, which indicates that the curvature of field of the optical lens 300 is better corrected; it can be seen from fig. 12 that the vertical chromatic aberration of the longest wavelength and the shortest wavelength are controlled within ± 4.5 microns, which indicates that the vertical chromatic aberration of the optical lens 300 is well corrected.

Please refer to table 7, which shows the optical characteristics corresponding to the optical lens provided in the above three embodiments, including the field angle 2 θ, the total optical length TTL, the image height IH corresponding to the maximum half field, the effective focal length f, and the related values corresponding to each of the aforementioned conditional expressions.

TABLE 7

Compared with the prior art, the optical lens provided by the invention at least has the following advantages:

(1) because the glass has better light transmission and higher refractive index, the optical lens provided by the invention can ensure that the lens has good thermal stability in high and low temperature environments through reasonable collocation of seven glass-plastic mixed lenses, has more excellent light transmittance and optical performance, and realizes high pixel of the lens.

(2) The optical lens provided by the invention adopts seven glass-plastic mixed lenses, meets the requirement of the lens on a large field angle through specific surface shape collocation and reasonable focal power distribution, and has the advantages of high pixel, good resolving power and the like.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above examples are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An optical lens, comprising, in order from an object side to an image plane along an optical axis:

the lens comprises a first lens with negative focal power, a second lens and a third lens, wherein the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

the second lens is provided with negative focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a concave surface;

the lens system comprises a first lens, a second lens and a third lens, wherein the first lens is provided with positive focal power, the object-side surface of the first lens is a concave surface, and the image-side surface of the first lens is a convex surface;

a diaphragm;

the fourth lens is provided with positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface;

a fifth lens element having a negative optical power, an object-side surface of the fifth lens element being convex at a paraxial region and an image-side surface of the fifth lens element being concave;

the lens comprises a sixth lens with positive focal power, wherein the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface;

a seventh lens having a negative optical power, an image side surface of the seventh lens being concave at a paraxial region;

wherein the first lens to the seventh lens at least comprise a spherical lens and an aspherical lens.

2. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

0.7mm/rad<f/θ<0.9mm/rad；

100°<θ<110°；

wherein f represents an effective focal length of the optical lens, and θ represents a maximum half field angle of the optical lens.

3. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

6.5<DM1/f<9；

where DM1 represents the effective diameter of the first lens and f represents the effective focal length of the optical lens.

4. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

-6<f2/f<-2；

-5<R21/R22<-1.5；

where f2 denotes a focal length of the second lens, f denotes an effective focal length of the optical lens, R21 denotes a radius of curvature of an object-side surface of the second lens, and R22 denotes a radius of curvature of an image-side surface of the second lens.

5. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

3.5<f3/f<7；

1<R31/R32<20；

where f3 denotes a focal length of the third lens, f denotes an effective focal length of the optical lens, R31 denotes a radius of curvature of an object-side surface of the third lens, and R32 denotes a radius of curvature of an image-side surface of the third lens.

6. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

1<f4/f<2；

where f4 denotes a focal length of the fourth lens, and f denotes an effective focal length of the optical lens.

7. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

-2.5<f5/f<-1；

0.6<R52/f<1.2；

where f5 denotes a focal length of the fifth lens, f denotes an effective focal length of the optical lens, and R52 denotes a radius of curvature of an image side surface of the fifth lens.

8. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

1<f6/f<2；

-6<R61/R62<-1；

wherein R61 denotes a radius of curvature of an object side surface of the sixth lens, R62 denotes a radius of curvature of an image side surface of the sixth lens, f6 denotes a focal length of the sixth lens, and f denotes an effective focal length of the optical lens.

9. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

-5<f7/f<-1；

1<R72/f<60；

where f7 denotes a focal length of the seventh lens, f denotes an effective focal length of the optical lens, and R72 denotes a radius of curvature of an image side surface of the seventh lens.

10. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

Nd1>1.7；

Nd3>1.7；

where Nd1 denotes a refractive index of the first lens, and Nd3 denotes a refractive index of the third lens.

11. An optical lens according to claim 1, characterized in that the optical lens satisfies the following conditional expression:

7<TTL/f<9；

0.08<BFL/TTL<0.15；

wherein, TTL represents the optical total length of the optical lens, f represents the effective focal length of the optical lens, and BFL represents the optical back focus of the optical lens.