CN220553029U

CN220553029U - Optical lens

Info

Publication number: CN220553029U
Application number: CN202322202791.3U
Authority: CN
Inventors: 张野; 汪磊
Original assignee: Shanghai Fengmei Optical Technology Co ltd
Current assignee: Shanghai Fengmei Optical Technology Co ltd
Priority date: 2023-08-16
Filing date: 2023-08-16
Publication date: 2024-03-01
Anticipated expiration: 2033-08-16

Abstract

The utility model relates to an optical lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; the first lens is of 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 is of 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 is of positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens is of 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 is of negative focal power, the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface; the sixth lens element with positive refractive power has a convex object-side surface and a convex image-side surface. The optical lens has the following advantages: the lens is composed of 6 lenses, has the characteristics of low ghost, low stray light, high definition, ultra-wide angle, large aperture and the like.

Description

Optical lens

Technical Field

The present utility model relates to the field of optical imaging, and in particular, to an optical lens.

Background

In recent years, optical lenses are widely used in the fields of mobile devices, vehicle devices, sports devices, safety monitoring devices, and the like. As a monitoring device, the optical information acquired by the optical lens must be accurate, the information contained in the object and the image plane must be consistent, and strong energy ghosts and parasitic lights cannot be allowed to appear, otherwise, the calculation accuracy is affected, and the false judgment of an early warning system is caused; meanwhile, the optical lens requires a wide field of view, otherwise, the optical lens has a monitoring dead angle. Therefore, there is a need for an optical lens having a large angle of view and a high imaging quality.

Disclosure of Invention

An object of the present utility model is to provide an optical lens with less ghosting.

Another object of the present application is to provide an optical lens, which has an ultra-wide angle.

The technical scheme that this application adopted is: an optical lens sequentially comprising, from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens;

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

the fourth lens is of 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 is of negative focal power, the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface;

the sixth lens element with positive refractive power has a convex object-side surface and a convex image-side surface.

Compared with the prior art, the lens has the advantages that the lens is composed of 6 lenses, has the characteristics of low ghost images and low stray light, and has the characteristics of high definition, ultra-wide angle, large aperture and the like.

In some embodiments of the present application, the fifth lens and the sixth lens form a cemented lens.

In some embodiments of the present application, the focal length value F5 of the fifth lens and the focal length value F6 of the sixth lens satisfy: F5/F6 is more than or equal to 0.5 and less than or equal to 1.5.

In some embodiments of the present application, the focal length value F56 of the cemented lens and the entire set of focal length values F of the optical lens satisfy: the F56/F is less than or equal to 6.

In some embodiments of the present application, a diaphragm for restricting the light beam is disposed between the third lens and the fourth lens.

In some embodiments of the present application, the aperture is proximate to the object side of the fourth lens.

In some embodiments of the present application, the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy: (FOV. Times.F)/H.gtoreq.100.

In some embodiments of the present application, the total optical length TTL of the optical lens satisfies: TTL is less than or equal to 14.

In some embodiments of the present application, the optical back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: BFL/TTL is more than or equal to 0.15.

In some embodiments of the present application, the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy: ENPD/TTL is more than or equal to 0.04.

In some embodiments of the present application, the refractive index of the first lens satisfies: nd1 is more than or equal to 1.65.

In some embodiments of the present application, the refractive index of the fourth lens satisfies: nd4 is more than or equal to 1.7.

In some embodiments of the present application, the central curvature radius R2 of the image side surface of the first lens and the central curvature radius R3 of the image side surface of the second lens satisfy: -4.0 < R2-R3)/(R2+R3) < 1.

In some embodiments of the present application, the focal length value F1 of the first lens and the entire set of focal length values F of the optical lens satisfy: -6< F1/F <0.

In some embodiments of the present application, the focal length value F2 of the second lens and the entire set of focal length values F of the optical lens satisfy: -3 < F2/F <0.

In some embodiments of the present application, the focal length value F3 of the third lens and the entire set of focal length values F of the optical lens satisfy: F3/F is more than 0 and less than 10.

In some embodiments of the present application, the focal length value F4 of the fourth lens and the entire set of focal length values F of the optical lens satisfy: F4/F > 3.

In some embodiments of the present application, the focal length value F5 of the fifth lens and the entire set of focal length values F of the optical lens satisfy: -4 < F5/F <0.

In some embodiments of the present application, the focal length value F6 of the sixth lens and the entire set of focal length values F of the optical lens satisfy: 0< F6/F <4.

In some embodiments of the present application, the central curvature radius R1 of the first lens object-side surface and the entire set of focal length values F of the optical lens satisfy: R1/F is more than 8 and less than 12.

In some embodiments of the present application, the radius of curvature R8 of the fourth lens object-side surface and the entire set of focal length values F of the optical lens satisfy: R8/F is more than 3 and less than 6.

In some embodiments of the present application, the curvature radius R9 of the image side surface of the fourth lens and the entire set of focal length values F of the optical lens satisfy: R9/F > 3.5.

In some embodiments of the present application, the radius of the maximum light transmission aperture of the image side surface of the second lens corresponding to the maximum field angle of the optical lens is d (S4) and the sagittal value SAG (S4) corresponding thereto satisfy: arctan (SAG (S4)/d (S4)). Ltoreq.62°.

In some embodiments of the present application, the second lens, the third lens, the fifth lens, and the sixth lens are all aspherical lenses.

In some embodiments of the present application, the aspherical surfaces of the two lenses, the third lens, the fifth lens and the sixth lens satisfy the following equations:

wherein Z is the distance between the curved surface and the curved surface vertex in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the curved surface vertex, k is the quadric surface coefficient, and A, B, C, D, E is the higher order coefficient.

Drawings

FIG. 1 is a schematic structural view of embodiment 1 of the present utility model;

FIG. 2 is a schematic structural view of embodiment 2 of the present utility model;

fig. 3 is a schematic structural view of embodiment 3 of the present utility model.

Detailed Description

In order to further describe the technical means and effects adopted by the present utility model for achieving the intended purpose, the following detailed description will refer to the specific implementation, structure, characteristics and effects according to the present utility model with reference to the accompanying drawings and preferred embodiments.

The optical lens according to the exemplary embodiment of the present application may include, for example, six lenses having optical power, i.e., a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6. The six lenses are sequentially arranged from the object side to the image side along the optical axis.

The first lens element 1 may have a negative refractive power, a convex object-side surface and a concave image-side surface, and may be made of glass material.

The second lens element 2 has a negative refractive power, and has a concave object-side surface and a concave image-side surface, and is made of plastic.

The third lens element 3 has a positive refractive power, and has a convex object-side surface and a convex image-side surface, and is made of plastic.

The fourth lens element 4 has positive refractive power, and has a convex object-side surface and a convex image-side surface, and is made of glass material.

The fifth lens element 5 can have negative refractive power, wherein its object-side surface is convex, and its image-side surface is concave, and plastic material is selected.

The sixth lens element 6 with positive refractive power has a convex object-side surface and a convex image-side surface, and is made of plastic.

The fifth lens 5 and the sixth lens 6 form a cemented lens 7, which can effectively correct chromatic aberration of the optical lens, reduce decentering sensitivity of the optical lens, balance aberration of the optical lens, improve imaging quality of the optical lens, reduce assembly sensitivity of the optical lens, further reduce difficulty of processing technology of the optical lens, and improve assembly yield of the optical lens.

A diaphragm 8 for restricting the light beam is provided between the third lens 3 and the fourth lens 4; the diaphragm 8 may be disposed near the object side surface of the fourth lens element 4, so as to reduce the generation of astigmatism of the optical lens element and improve the image quality. The diaphragm 8 is arranged at the middle part of the whole system, light can be smoothly transited to the rear group, and the light reaches the image plane at a small angle, so that the relative illumination of the whole system is improved.

The optical lens consists of 6 lenses, has the characteristics of low ghost, low stray light, high definition, ultra-wide angle, large aperture and the like, adopts a glass-plastic mixed framework, and can still keep stable performance in severe high-low temperature environments through reasonable lens collocation.

In an exemplary embodiment, the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy: the (FOV multiplied by F)/H is more than or equal to 100, so that the half view field can reach more than 100 degrees, and the full view field can meet the requirement of looking around.

In an exemplary embodiment, the total optical length TTL of the optical lens satisfies: TTL is less than or equal to 14, and the total length of the optical lens is controlled, so that the miniaturized optical lens can be obtained.

In an exemplary embodiment, the optical back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: BFL/TTL is more than or equal to 0.15, so that the back focal length of the optical lens is longer, and the back end of the optical lens keeps enough space, thereby being beneficial to the assembly of the module.

In an exemplary embodiment, the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy: ENPD/TTL is more than or equal to 0.04, realizes small FNO, is favorable for realizing large aperture characteristic, and provides more incident light for the optical lens.

In an exemplary embodiment, the refractive index of the first lens 1 satisfies: nd1 is more than or equal to 1.65, and the first lens 1 is preferably made of high-refractive-index materials, so that the reduction of the caliber of the front end and the improvement of the imaging quality are facilitated.

In an exemplary embodiment, the refractive index of the fourth lens 4 satisfies: nd4 is more than or equal to 1.7, and glass material is selected for the fourth lens 4, and reasonable distribution of positions where the glass lens and the plastic lens are placed is favorable for realizing temperature characteristics, and the lens can still guarantee better imaging quality under high and low temperature conditions.

In an exemplary embodiment, the focal length value F1 of the first lens 1 and the entire set of focal length values F of the optical lens satisfy: -6< F1/F <0. The first lens 1 has a proper negative power, which is advantageous for enlarging the angle of view of the optical lens.

In an exemplary embodiment, the focal length value F2 of the second lens 2 and the entire set of focal length values F of the optical lens satisfy: -3 < F2/F <0. The second lens 2 has proper negative focal power, and can share the negative focal power at the front end of the optical lens, so that the overlarge deflection of light caused by overlarge focal power of the first lens 1 is avoided, and the difficulty of chromatic aberration correction of the optical lens is reduced.

In an exemplary embodiment, the focal length value F3 of the third lens 3 and the entire set of focal length values F of the optical lens satisfy: F3/F is more than 0 and less than 10. The third lens 3 has proper positive focal power, is favorable for smooth transition of light, is convenient for correcting astigmatism and field curvature, and improves the imaging quality of the optical lens.

In an exemplary embodiment, the focal length value F4 of the fourth lens 4 and the entire set of focal length values F of the optical lens satisfy: F4/F > 3. The focal length of the fourth lens 4 is controlled, the focal power of the whole optical system can be reasonably distributed, the temperature characteristic is favorably realized, and the lens can still ensure better imaging quality under the high-low temperature condition.

In an exemplary embodiment, the focal length value F5 of the fifth lens 5 and the entire set of focal length values F of the optical lens satisfy: -4 < F5/F <0; the focal length value F6 of the sixth lens 6 and the focal length value F of the whole set of optical lenses satisfy: 0< F6/F <4. The negative film of the cemented lens 7 is in front, and the positive film is behind, so that the light rays of the front beam can be rapidly converged after being diverged, the reduction of the optical path of the light rays at the rear is facilitated, and the short TTL is realized.

In an exemplary embodiment, the focal length value F5 of the fifth lens 5 and the focal length value F6 of the sixth lens 6 satisfy: F5/F6 is more than or equal to 0.5 and less than or equal to 1.5. The focal length values of the two lenses of the cemented lens 7 are similar, which is favorable for smooth transition of light and improves the resolution quality.

In an exemplary embodiment, the focal length value F56 of the cemented lens 7 and the entire group focal length value F of the optical lens satisfy: the F56/F is less than or equal to 6. The short focal length is beneficial to light receiving, light passing quantity is guaranteed, relative illuminance is improved, and image circle is increased to achieve the looking-around requirement.

In an exemplary embodiment, the center radius of curvature R1 of the object side surface of the first lens 1 and the entire set of focal length values F of the optical lens satisfy: R1/F is more than 8 and less than 12. The control of the lower limit is beneficial to the entry of light rays with large angles, so as to meet the looking-around requirement; the upper control limit is beneficial to reducing the effective caliber of the lens and realizing miniaturization.

In an exemplary embodiment, the central curvature radius R2 of the image side surface of the first lens element 1 and the central curvature radius R3 of the image plane of the second lens element 2 satisfy: -4.0 < R2-R3)/(R2+R3) < 1. It is possible to correct the aberration of the optical system and ensure that the incident light is gentle when the light emitted from the first lens 1 is incident on the first surface of the second lens 2, thereby reducing the tolerance sensitivity of the optical system.

In an exemplary embodiment, the radius of curvature R8 of the object side surface of the fourth lens element 4 and the entire set of focal length values F of the optical lens element satisfy: R8/F is more than 3 and less than 6. The above range is satisfied, which is beneficial to reducing the energy of the ghost image generated by reflection in the center area of the object side surface of the fourth lens 4 projected on the image plane and improving the imaging quality of the optical lens.

In an exemplary embodiment, the curvature radius R9 of the image side surface of the fourth lens 4 and the entire set of focal length values F of the optical lens satisfy: R9/F > 3.5. The lens shape is gentle by meeting the range, and the lens shape is more gentle, so that the tolerance sensitivity of the optical system is reduced, and the production yield is improved.

In an exemplary embodiment, the radius d (S4) of the maximum aperture of the image side surface of the second lens element 2 corresponding to the maximum field angle of the optical lens and the corresponding sagittal value SAG (S4) satisfy: arctan (SAG (S4)/d (S4)). Ltoreq.62°. The opening angle of the second lens 2 is controlled, so that the phenomenon that the edge of the light ray is reflected to form a ghost image can be avoided.

In an exemplary embodiment, the second lens 2, the third lens 3, the fifth lens 5 and the sixth lens 6 are all aspherical lenses; the aspherical surfaces of the two lenses 2, the third lens 3, the fifth lens 5 and the sixth lens 6 satisfy the following equations:

wherein Z is the distance between the curved surface and the curved surface vertex in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the curved surface vertex, k is the quadric surface coefficient, and A, B, C, D, E is the fourth-order, sixth-order, eighth-order, tenth-order and twelfth-order surface coefficients respectively.

Example 1:

as shown in fig. 1, the optical lens provided in the present embodiment includes, in order from an object side to an image side along an optical axis: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6;

the first lens element 1 has a negative refractive power, wherein an object-side surface S1 thereof is convex, and an image-side surface S2 thereof is concave;

the second lens element 2 has a negative refractive power, an object-side surface S3 thereof is a concave surface, and an image-side surface S4 thereof is a concave surface;

the third lens element 3 has positive refractive power, wherein an object-side surface S5 thereof is convex, and an image-side surface S6 thereof is convex;

the fourth lens element 4 has positive refractive power, wherein an object-side surface S8 thereof is convex, and an image-side surface S9 thereof is convex;

the fifth lens element 5 has negative refractive power, wherein an object-side surface S10 thereof is convex, and an image-side surface S11 thereof is concave;

the sixth lens element 6 has a positive refractive power, wherein an object-side surface S11 thereof is convex, and an image-side surface S12 thereof is convex.

The fifth lens 5 and the sixth lens 6 constitute a cemented lens 7; a diaphragm 8 for restricting the light beam is provided between the third lens 3 and the fourth lens 4.

Optionally, the optical lens may further include an optical filter 10 having an object side surface S13 and an image side surface S14. The filter 10 can be used to correct color deviations, and light from an object passes sequentially through the surfaces S1 to S14 and is finally imaged on the imaging plane IMA.

The detailed parameters are shown in Table 1 below, wherein the unit of the radius of curvature R and the thickness T are both millimeters;

TABLE 1

The second lens element 2 is an aspheric lens element, and both the object-side surface S3 and the image-side surface S4 thereof are aspheric. The third lens element 3 has an aspherical lens element, and an object-side surface S5 and an image-side surface S6 thereof are both aspherical. The fifth lens element 5 has an aspheric object-side surface S10 and an image-side surface S11. The sixth lens element 6 has an aspherical lens element, and an object-side surface S11 and an image-side surface S12 thereof are both aspherical.

Conical coefficients k and higher order coefficients A, B, C, D and E of the aspherical lens surfaces S3, S4, S5, S6, S10, S11 and S12, as shown in table 2 below:

TABLE 2

Table 3 below shows the entire set of focal length values F of the optical lens, the maximum field angle FOV of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the total optical length TTL of the optical lens, the optical back focus BFL of the optical lens, the entrance pupil diameter ENPD of the optical lens, the focal length values F1-F6 of the first lens to the sixth lens, the focal length value F56 of the cemented lens composed of the fifth lens and the sixth lens, the central radius of curvature R1 of the first lens object side surface S1 and the central radius of curvature R2 of the image side surface S2, the central radius of curvature R3 of the second lens object side surface S3 and the central radius of curvature R4 of the image side surface S4, the central radius of curvature R8 of the fourth lens object side surface S8 and the central radius of curvature R9 of the image side surface S9 in the specific embodiment.

TABLE 3 Table 3

FOV(°)	200.000	R9(mm)	-4.000
				F(mm)	1.132	(FOV×F)/H	115.725
D(mm)	5.317	BFL/TTL	0.191
				H(mm)	1.956	ENPD/TTL	0.051
TTL(mm)	13.502	F1/F	-4.701
				BFL(mm)	2.584	F2/F	-2.246
F1(mm)	-5.321	F3/F	5.415
				F2(mm)	-2.542	F4/F	3.126
F3(mm)	6.129	F5/F	-1.841
				F4(mm)	3.538	F6/F	1.605
F5(mm)	-2.084	\|F5/F6\|	1.148
				F6(mm)	1.816	\|F56/F\|	5.618
F56(mm)	6.359	R1/F	9.542
				R1(mm)	10.800	(R2-R3)/(R2+R3)	-1.271
R2(mm)	3.140	R8/F	5.743
				R3(mm)	-26.293	\|R9/F\|	3.534
R8(mm)	6.500

Example 2:

as shown in fig. 2, the optical lens provided in the present embodiment includes, in order from an object side to an image side along an optical axis: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6;

The detailed parameters are shown in Table 4 below, wherein the radius of curvature R and the thickness T are each in millimeters;

TABLE 4 Table 4

Conical coefficients k and higher order coefficients A, B, C, D and E of the aspherical lens surfaces S3, S4, S5, S6, S10, S11 and S12, table 5 below:

TABLE 5

Face number

K

A

B

C

D

E

S3

9.72E+01

-1.38E-04

1.99E-03

-5.37E-04

3.24E-05

1.02E-05

S4

0

9.56E-02

-3.65E-03

6.60E-03

1.28E-03

3.85E-04

S5

9.45E+01

2.12E-03

-7.03E-03

1.38E-02

-4.79E-03

-2.15E-03

S6

0

-6.32E-02

5.95E-02

-3.37E-02

6.36E-03

5.02E-03

S10

3.85E+01

-3.72E-02

5.59E-02

-9.98E-02

7.83E-02

-2.15E-02

S11

0

2.17E-01

-1.72E-01

1.14E-01

-9.26E-02

5.24E-02

S12

-6.24E+01

-1.52E-01

1.37E-01

-7.05E-02

1.06E-02

6.04E-03

Table 6 below shows the entire set of focal length values F of the optical lens, the maximum field angle FOV of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the total optical length TTL of the optical lens, the optical back focus BFL of the optical lens, the entrance pupil diameter ENPD of the optical lens, the focal length values F1-F6 of the first lens to the sixth lens, the focal length value F56 of the cemented lens composed of the fifth lens and the sixth lens, the central radius of curvature R1 of the first lens object side surface S1 and the central radius of curvature R2 of the image side surface S2, the central radius of curvature R3 of the second lens object side surface S3 and the central radius of curvature R4 of the image side surface S4, the central radius of curvature R8 of the fourth lens object side surface S8 and the central radius of curvature R9 of the image side surface S9 in the specific embodiment.

TABLE 6

Example 3:

as shown in fig. 3, the optical lens provided in the present embodiment of the present utility model sequentially includes, from an object side to an image side along an optical axis: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6;

The detailed parameters are shown in Table 7 below, wherein the radius of curvature R and the thickness T are each in millimeters;

TABLE 7

Conical coefficients k and higher order coefficients A, B, C, D and E for aspherical lens surfaces S3, S4, S5, S6, S10, S11 and S12, as shown in table 8 below:

TABLE 8

Face number

K

A

B

C

D

E

S3

9.80E+01

1.44E-02

-5.64E-04

-3.45E-04

7.10E-05

5.40E-06

S4

-4.47E+00

1.64E-01

-3.41E-02

1.00E-02

2.32E-03

8.28E-04

S5

-6.72E+01

-1.52E-02

-1.51E-02

2.06E-02

-1.02E-02

-3.32E-03

S6

-1.00E+02

-8.32E-02

6.30E-02

-4.09E-02

8.11E-03

7.24E-03

S10

-7.75E+01

-3.96E-02

4.96E-02

-1.00E-01

9.12E-02

-3.44E-02

S11

-2.30E+00

1.29E-01

-1.27E-01

1.46E-01

-1.42E-01

8.27E-02

S12

-5.87E+01

-1.99E-01

2.22E-01

-1.51E-01

3.57E-02

1.90E-02

Table 9 below gives the entire set of focal length values F of the optical lens, the maximum field angle FOV of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the total optical length TTL of the optical lens, the optical back focus BFL of the optical lens, the entrance pupil diameter ENPD of the optical lens, focal length values F1-F6 of the first lens to the sixth lens, the cemented lens focal length value F56 composed of the fifth lens and the sixth lens, the central radius of curvature R1 of the first lens object side surface S1 and the central radius of curvature R2 of the image side surface S2, the central radius of curvature R3 of the second lens object side surface S3 and the central radius of curvature R4 of the image side surface S4, the central radius of curvature R8 of the fourth lens object side surface S8 and the central radius of curvature R9 of the image side surface S9 in the specific embodiment.

TABLE 9

The present utility model is not limited to the above embodiments, but is capable of modification and variation in detail, and other modifications and variations can be made by those skilled in the art without departing from the scope of the present utility model.

Claims

1. An optical lens, comprising, in order from an object side to an image side along an optical axis: a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5) and a sixth lens (6);

the first lens (1) 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 (2) 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 (3) has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;

the fourth lens (4) 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 (5) has negative focal power, the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface;

the sixth lens (6) 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.

2. An optical lens according to claim 1, wherein: the fifth lens (5) and the sixth lens (6) form a cemented lens (7); the focal length value F5 of the fifth lens (5) and the focal length value F6 of the sixth lens (6) satisfy the following conditions: F5/F6 is more than or equal to 0.5 and less than or equal to 1.5; the focal length value F56 of the cemented lens (7) and the focal length value F of the whole group of the optical lens satisfy the following conditions: the F56/F is less than or equal to 6.

3. An optical lens according to claim 1, wherein: a diaphragm (8) for limiting the light beam is arranged between the third lens (3) and the fourth lens (4); the diaphragm (8) is close to the object side surface of the fourth lens (4).

4. An optical lens according to claim 1, wherein: the maximum field angle FOV of the optical lens, the whole set of focal length values F of the optical lens and the image height H corresponding to the maximum field angle of the optical lens satisfy: (FOV. Times.F)/H.gtoreq.100.

5. An optical lens according to claim 1, wherein: the total optical length TTL of the optical lens satisfies: TTL is less than or equal to 14; the optical back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: BFL/TTL is more than or equal to 0.15; the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy the following conditions: ENPD/TTL is more than or equal to 0.04.

6. An optical lens according to claim 1, wherein: the refractive index of the first lens (1) satisfies: nd1 is more than or equal to 1.65; the refractive index of the fourth lens (4) satisfies: nd4 is more than or equal to 1.7; the central curvature radius R2 of the image side surface of the first lens (1) and the central curvature radius R3 of the image object surface of the second lens (2) meet the following conditions: -4.0 < R2-R3)/(R2+R3) < 1.

7. An optical lens according to claim 1, wherein: the focal length value F1 of the first lens (1) and the focal length value F of the whole group of the optical lens meet the following conditions: -6< F1/F <0; the focal length value F2 of the second lens (2) and the focal length value F of the whole group of the optical lens meet the following conditions: -3 < F2/F <0; the focal length value F3 of the third lens (3) and the focal length value F of the whole group of the optical lens meet the following conditions: F3/F is more than 0 and less than 10; the focal length value F4 of the fourth lens (4) and the focal length value F of the whole group of the optical lens meet the following conditions: F4/F > 3; the focal length value F5 of the fifth lens (5) and the focal length value F of the whole group of the optical lens meet the following conditions: -4 < F5/F <0; the focal length value F6 of the sixth lens (6) and the focal length value F of the whole group of the optical lens satisfy the following conditions: 0< F6/F <4.

8. An optical lens according to claim 1, wherein: the center curvature radius R1 of the object side surface of the first lens (1) and the whole group focal length value F of the optical lens meet the following conditions: R1/F is more than 8 and less than 12; the curvature radius R8 of the object side surface of the fourth lens (4) and the whole group focal length value F of the optical lens meet the following conditions: R8/F is more than 3 and less than 6; the curvature radius R9 of the image side surface of the fourth lens (4) and the whole group focal length value F of the optical lens meet the following conditions: R9/F > 3.5.

9. An optical lens according to claim 1, wherein: the radius d (S4) of the maximum aperture of the image side surface of the second lens (2) corresponding to the maximum field angle of the optical lens and the corresponding sagittal value SAG (S4) satisfy the following conditions: arctan (SAG (S4)/d (S4)). Ltoreq.62°.

10. An optical lens according to claim 1, wherein: the second lens (2), the third lens (3), the fifth lens (5) and the sixth lens (6) are all aspheric lenses; the aspherical surfaces of the two lenses (2), the third lens (3), the fifth lens (5) and the sixth lens (6) satisfy the following equations: