CN212379651U

CN212379651U - Wide-angle lens

Info

Publication number: CN212379651U
Application number: CN202021841374.3U
Authority: CN
Inventors: 姚晨; 何剑炜; 张磊
Original assignee: Dongguan Yutong Optical Technology Co Ltd
Current assignee: Dongguan Yutong Optical Technology Co Ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2021-01-19
Anticipated expiration: 2030-08-28

Abstract

The utility model discloses a wide-angle lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are arranged in sequence from an object plane to an image plane along an optical axis; the first lens and the sixth lens are negative focal power lenses, the third lens, the fourth lens, the fifth lens and the seventh lens are positive focal power lenses, and the second lens is a negative focal power lens or a positive focal power lens; the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, and the focal length of the wide-angle lens is f, wherein: | f1/f | is more than or equal to 0.3 and less than or equal to 2.6; the | f2/f | is more than or equal to 2; | f3/f | is more than or equal to 2.3 and less than or equal to 7.2; the | f4/f | is more than or equal to 0.8; | f5/f | is more than or equal to 0.67 and less than or equal to 2.94; | f6/f | is more than or equal to 0.32 and less than or equal to 2.77; and | f7/f | ≧ 0.16. The utility model provides a wide-angle lens guarantees under low-cost prerequisite, has satisfied the little control demand of high definition and distortion.

Description

Wide-angle lens

Technical Field

The embodiment of the utility model provides a relate to optical device technical field, especially relate to a wide-angle lens.

Background

The security industry in the rapid development period is different day by day, especially in the field of video monitoring, the rapid and rapid development is experienced in recent years, 1080P cannot completely meet the requirements of the current market at present, and 4K becomes the development trend in the future. In recent years, the live broadcast industry rises rapidly, and more stringent demands are provided for the lens to be more high-definition and more intelligent, however, the lens on the market cannot be considered in the aspects of definition, distortion and cost, and the lens with higher definition has larger distortion, so that a shot image is not real and has very high cost, and therefore, the problem needs to be solved by developing a lens with low cost, high definition and very small distortion.

SUMMERY OF THE UTILITY MODEL

The utility model provides a wide-angle lens guarantees under low-cost prerequisite, satisfies the little control demand of high definition and distortion.

The embodiment of the utility model provides a wide-angle lens, include first lens, second lens, third lens, fourth lens, fifth lens, sixth lens and the seventh lens that arrange along the optical axis in proper order from the object plane to the image plane;

the first lens and the sixth lens are both negative focal power lenses, the third lens, the fourth lens, the fifth lens and the seventh lens are all positive focal power lenses, and the second lens is a negative focal power lens or a positive focal power lens;

the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, and the focal length of the wide-angle lens is f, wherein:

0.3≤|f1/f|≤2.6；|f2/f|≥2；2.3≤|f3/f|≤7.2；|f4/f|≥0.8；0.67≤|f5/f|≤2.94；0.32≤|f6/f|≤2.77；|f7/f|≥0.16。

optionally, the second lens is a negative focal power lens; the third lens is a glass spherical lens, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all plastic aspheric lenses; the wide-angle lens further comprises a first diaphragm, and the first diaphragm is arranged in an optical path between the fourth lens and the fifth lens;

or, the second lens is a positive focal power lens; the fifth lens is a glass aspheric lens, and the first lens, the second lens, the third lens, the fourth lens, the sixth lens and the seventh lens are all plastic aspheric lenses; the wide-angle lens still includes the second diaphragm, the second diaphragm sets up the third lens with in the light path between the fourth lens.

Optionally, the refractive index of the first lens is n 1; the refractive index of the second lens is n2, and the Abbe number is v 2; the refractive index of the third lens is n3, and the Abbe number is v 3; the refractive index of the fourth lens is n4, and the Abbe number is v 4; the refractive index of the seventh lens is n 7; wherein:

1.43≤n1≤1.9；1.50≤n2≤1.75，19≤v2≤56；n3≥1.43，v3≥18.6；1.53≤n4≤1.68，v4≥19；1.53≤n7≤1.67。

optionally, the rise of the object side surface of the first lens is SAG11, and the rise of the image side surface of the first lens is SAG12, wherein 0.08 ≦ SAG11/SAG12 ≦ 1.5.

Optionally, the radius of curvature of the object-side surface of the second lens is R21, where | R21| ≧ 1.42.

Optionally, the center thickness of the fourth lens is CT4, the center thickness of the fifth lens is CT5, wherein | CT4/CT5| ≦ 1.88.

Optionally, the curvature radius of the object-side surface of the fifth lens is R51, and the curvature radius of the image-side surface of the fifth lens is R52, where | R51/R52| ≧ 2.23.

Optionally, the fourth lens is a meniscus lens.

Optionally, a distance between an optical axis center of an image-side surface of the seventh lens element and the image plane is BFL, a distance between an optical axis center of an object-side surface of the first lens element and the image plane is TTL, and BFL/TTL is greater than or equal to 0.11 and less than or equal to 0.89.

Optionally, the aperture of the wide-angle lens is F, wherein F/F is more than or equal to 0.6 and less than or equal to 2.8.

The embodiment of the utility model provides a wide-angle lens, through the lens quantity that rationally sets up in the wide-angle lens, the focal power of each lens and the relative relation between each lens focus, under the prerequisite of low cost, the equilibrium of the angle of incidence size of group's lens around guaranteeing the wide-angle lens reduces the sensitivity of camera lens to the aberration is corrected when the super large light ring, guarantees that the wide-angle lens has higher resolving power, satisfies the little control demand of high definition and distortion.

Drawings

Fig. 1 is a schematic structural diagram of a wide-angle lens provided in an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another wide-angle lens provided in an embodiment of the present invention;

fig. 3 is a spherical aberration curve chart of a wide-angle lens according to a first embodiment of the present invention;

fig. 4 is a light fan diagram of a wide-angle lens according to a first embodiment of the present invention;

fig. 5 is a schematic diagram of a wide-angle lens according to an embodiment of the present invention;

fig. 6 is a vertical axis chromatic aberration of a wide-angle lens according to a first embodiment of the present invention;

fig. 7 is a field curvature distortion diagram of a wide-angle lens according to a first embodiment of the present invention;

fig. 8 is an MTF diagram of a wide-angle lens according to an embodiment of the present invention;

fig. 9 is a spherical aberration curve chart of a wide-angle lens according to a second embodiment of the present invention;

fig. 10 is a light fan diagram of a wide-angle lens according to a second embodiment of the present invention;

fig. 11 is a schematic diagram of a wide-angle lens according to a second embodiment of the present invention;

fig. 12 is a vertical axis chromatic aberration of a wide-angle lens provided in the second embodiment of the present invention;

fig. 13 is a field curvature distortion diagram of a wide-angle lens according to an embodiment of the present invention;

fig. 14 is an MTF diagram of a wide-angle lens according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a wide-angle lens according to an embodiment of the present invention, as shown in fig. 1, the wide-angle lens according to an embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170, which are sequentially arranged from an object plane to an image plane along an optical axis; the first lens 110 and the sixth lens 160 are both negative focal power lenses, the third lens 130, the fourth lens 140, the fifth lens 150 and the seventh lens 170 are all positive focal power lenses, and the second lens 120 is a negative focal power lens or a positive focal power lens. The focal length of the first lens 110 is f1, the focal length of the second lens 120 is f2, the focal length of the third lens 130 is f3, the focal length of the fourth lens 140 is f4, the focal length of the fifth lens 150 is f5, the focal length of the sixth lens 160 is f6, the focal length of the seventh lens 170 is f7, and the focal length of the wide-angle lens is f, wherein: | f1/f | is more than or equal to 0.3 and less than or equal to 2.6; the | f2/f | is more than or equal to 2; | f3/f | is more than or equal to 2.3 and less than or equal to 7.2; the | f4/f | is more than or equal to 0.8; | f5/f | is more than or equal to 0.67 and less than or equal to 2.94; | f6/f | is more than or equal to 0.32 and less than or equal to 2.77; and | f7/f | ≧ 0.16.

Illustratively, the optical power is equal to the difference between the image-side and object-side beam convergence, which characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power is, the stronger the bending ability to the light ray is, and the smaller the absolute value of the focal power is, the weaker the bending ability to the light ray is. When the focal power is positive, the refraction of the light is convergent; when the focal power is negative, the refraction of the light is divergent. The optical power can be suitable for representing a certain refractive surface of a lens (namely, a surface of the lens), can be suitable for representing a certain lens, and can also be suitable for representing a system (namely a lens group) formed by a plurality of lenses together. In the wide-angle lens provided by the embodiment of the present invention, each lens can be fixed in a lens barrel (not shown in fig. 1), and the first lens 110 is a negative power lens for controlling the light incident angle of the optical system; the second lens 120 is a negative focal power lens or a positive focal power lens, the third lens 130 and the fourth lens 140 are both positive focal power lenses, and the third lens 130 and the fourth lens 140 are used for focusing the light beams in front; the fifth lens 150 is a positive power lens, the sixth lens 160 is a negative power lens, the seventh lens 170 is a positive power lens, and the fifth lens 150, the sixth lens 160 and the seventh lens 170 are used for correcting off-axis aberrations including aberrations such as field curvature, coma, astigmatism and the like. The whole lens ensures that the focal power of the optical system is approximately proportionally distributed, and the balance of the incident angles of the front and rear lens groups is ensured, so that the sensitivity of the lens is reduced, and the production possibility is improved.

Further, the focal length f1 of the first lens 110, the focal length f2 of the second lens 120, the focal length f3 of the third lens 130, the focal length f4 of the fourth lens 140, the focal length f5 of the fifth lens 150, the focal length f6 of the sixth lens 160, the focal length f7 of the seventh lens 170, and the focal length f of the wide-angle lens are set to satisfy: | f1/f | is more than or equal to 0.3 and less than or equal to 2.6; the | f2/f | is more than or equal to 2; | f3/f | is more than or equal to 2.3 and less than or equal to 7.2; the | f4/f | is more than or equal to 0.8; | f5/f | is more than or equal to 0.67 and less than or equal to 2.94; | f6/f | is more than or equal to 0.32 and less than or equal to 2.77; and | f7/f | ≧ 0.16. Through each lens focus of rational distribution, be favorable to the correction of aberration when the super large light ring, guarantee that this camera lens has higher resolving power.

With continued reference to fig. 1, optionally, the second lens 120 is a negative power lens, the third lens 130 is a glass spherical lens, and the first lens 110, the second lens 120, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 are all plastic aspheric lenses; the wide-angle lens further includes a first diaphragm 180, and the first diaphragm 180 is disposed in an optical path between the fourth lens 140 and the fifth lens 150.

The second lens 120 is a negative power lens for correcting the off-axis aberration. The third lens 130 is a glass spherical lens, and the first lens 110, the second lens 120, the fourth lens 140, the fifth lens 150, the sixth lens 160 and the seventh lens 170 are all plastic aspheric lenses, which have the function of correcting all high-order aberrations. Because the lens cost of plastics material is far less than the lens cost of glass material, the embodiment of the utility model provides an in the wide-angle camera lens, through setting up 6 plastics aspheric lens, the image quality is good, and is with low costs. And because the two materials have the mutual compensation function, the wide-angle lens can be ensured to be still normally used in high and low temperature environments. By disposing the first diaphragm 180 in the optical path between the fourth lens 140 and the fifth lens 150, the propagation direction of the light beam can be adjusted, and the incident angle of the light beam can be adjusted, which is beneficial to improving the imaging quality.

In other embodiments, the second lens 120 may also be a positive power lens. For example, fig. 2 is a schematic structural diagram of another wide-angle lens provided in an embodiment of the present invention, and as shown in fig. 2, the fifth lens 150 is a glass aspheric lens, and the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the sixth lens 160, and the seventh lens 170 are all plastic aspheric lenses; the wide-angle lens further includes a second diaphragm 190, and the second diaphragm 190 is disposed in an optical path between the third lens 130 and the fourth lens 140.

The fifth lens 150 is a glass aspheric lens, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the sixth lens 160 and the seventh lens 170 are all plastic aspheric lenses, and the aspheric lenses have the function of correcting all high-order aberrations. Because the lens cost of plastics material is far less than the lens cost of glass material, the embodiment of the utility model provides an in the wide-angle camera lens, through setting up 6 plastics aspheric lens, the image quality is good, and is with low costs. And because the two materials have the mutual compensation function, the wide-angle lens can be ensured to be still normally used in high and low temperature environments. By disposing the second diaphragm 190 in the optical path between the third lens 130 and the fourth lens 140, the propagation direction of the light beam can be adjusted, and the incident angle of the light beam can be adjusted, which is beneficial to improving the imaging quality.

It should be noted that the above material of the plastic aspheric lens can be various plastics known to those skilled in the art, and the material of the glass spherical lens can be various types of glass known to those skilled in the art, and the embodiment of the present invention is not repeated nor limited to this.

Optionally, the refractive index of the first lens 110 is n 1; the refractive index of the second lens 120 is n2, and the abbe number is v 2; the refractive index of the third lens 130 is n3, and the Abbe number is v 3; the refractive index of the fourth lens 140 is n4, and the abbe number is v 4; the refractive index of the seventh lens 170 is n 7; wherein: n1 is more than or equal to 1.43 and less than or equal to 1.9; n2 is more than or equal to 1.50 and less than or equal to 1.75, v2 is more than or equal to 19 and less than or equal to 56; n3 is more than or equal to 1.43, v3 is more than or equal to 18.6; n4 is more than or equal to 1.53 and less than or equal to 1.68, and v4 is more than or equal to 19; n7 is more than or equal to 1.53 and less than or equal to 1.67.

The refractive index is the ratio of the propagation speed of light in vacuum to the propagation speed of light in the medium, and is mainly used for describing the refractive power of materials to light, and the refractive indexes of different materials are different. The abbe number is an index for expressing the dispersion capability of the transparent medium, and the more severe the dispersion of the medium is, the smaller the abbe number is; conversely, the more slight the dispersion of the medium, the greater the abbe number. Therefore, the refractive index and the Abbe number of each lens in the wide-angle lens are matched, the balance of the incident angles of the front and rear lens groups is ensured, the sensitivity of the lens is reduced, and the high pixel resolution is realized.

Optionally, the rise of the object side surface of the first lens 110 is SAG11, and the rise of the image side surface of the first lens 110 is SAG12, wherein 0.08 ≦ SAG11/SAG12 ≦ 1.5.

Wherein the rise represents the vertical distance from the highest point to the lowest point on the lens surface, and 0.08 ≦ SAG11/SAG12 ≦ 1.5 is satisfied by arranging the rise SAG11 of the object-side surface and the rise SAG12 of the image-side surface of the first lens 110, which contributes to reasonable control of the light incident angle of the optical system.

Optionally, the radius of curvature of the object-side surface of the second lens 120 is R21, where | R21| ≧ 1.42.

The unit of the curvature radius is millimeter (mm), and the curvature radius R21 of the object side surface of the second lens 120 meets the requirement that R21 is greater than or equal to 1.42, so that the total length of a light path is favorably shortened, and the overall size of the lens is ensured to be small.

Optionally, the center thickness of the fourth lens 140 is CT4, and the center thickness of the fifth lens 150 is CT5, wherein | CT4/CT5| ≦ 1.88.

The central thickness CT4 of the fourth lens 140 and the central thickness CT5 of the fifth lens 150 are set to satisfy the condition that the total diameter CT4/CT5 is less than or equal to 1.88, so that the aperture of the wide-angle lens is reasonably controlled, and the aberration is corrected.

Optionally, the curvature radius of the object-side surface of the fifth lens 150 is R51, and the curvature radius of the image-side surface of the fifth lens 150 is R52, where | R51/R52| ≧ 2.23.

The radius of curvature R51 of the object-side surface of the fifth lens 150 and the radius of curvature R52 of the image-side surface of the fifth lens 150 are set to satisfy | R51/R52| ≧ 2.23, so that the object-side surface of the fifth lens 150 is relatively flat, which is beneficial to improving the imaging quality.

Optionally, the fourth lens 140 is a meniscus lens.

The fourth lens is the meniscus lens, which is helpful for correcting field curvature.

Optionally, a distance from an optical axis center of an image-side surface of the seventh lens element 170 to the image plane is BFL, and a distance from an optical axis center of an object-side surface of the first lens element 110 to the image plane is TTL, where BFL/TTL is greater than or equal to 0.11 and less than or equal to 0.89.

Wherein, the distance from the optical axis center of the image side surface of the seventh lens element 170 to the image surface can be understood as the back focal length of the wide-angle lens, the distance from the optical axis center of the object side surface of the first lens element 110 to the image surface can be understood as the optical total length of the wide-angle lens, and the relationship between the back focal length of the wide-angle lens and the optical total length of the wide-angle lens is reasonably set, so that the compact structure of the whole wide-angle lens can be ensured, and the integration degree of the wide-angle lens is high.

As a feasible implementation manner, the embodiment of the utility model provides a wide-angle lens's F number F and wide-angle lens's focus F satisfies 0.6 and is less than or equal to F/F and is less than or equal to 2.8, satisfies the little control demand of high definition and distortion when the super large light ring.

The embodiment of the utility model provides a wide-angle lens, through optical power, face type, abb number, central thickness etc. of each lens of rational distribution, under the prerequisite of low cost, the equilibrium of the angle of incidence size of group's lens around guaranteeing wide-angle lens reduces the sensitivity of camera lens to the aberration is corrected when the super large light ring, guarantees that wide-angle lens has higher resolving power, satisfies the little control demand of high definition and distortion.

Specific examples of the optical imaging lens group applicable to the above embodiments are further described below with reference to the drawings.

Example one

With reference to fig. 1, a wide-angle lens provided in the first embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged in sequence from an object plane to an image plane along an optical axis, wherein a first stop 180 is disposed in an optical path between the fourth lens 140 and the fifth lens 150. Table 1 shows optical physical parameters such as surface type, radius of curvature, thickness, and material of each lens in the wide-angle lens provided in the first embodiment.

TABLE 1 optical physical parameters of Wide-Angle lens

The surface numbers are numbered according to the surface order of the lenses, for example, the surfaces with the

surface numbers

1 and 2 are the object-side surface and the image-side surface of the first lens 110, the surfaces with the

surface numbers

3 and 4 are the object-side surface and the image-side surface of the second lens 120, and so on. The curvature radius represents the bending degree of the surface of the lens, a positive value represents that the surface is bent to the image surface side, and a negative value represents that the surface is bent to the object surface side; thickness represents the central axial distance from the current surface to the next surface, and the radius of curvature and thickness are both in millimeters (mm).

In addition to the above implementation, optionally, the third lens 130 is a glass spherical lens, and the first lens 110, the second lens 120, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 are all plastic aspheric lenses. The embodiment of the utility model provides a wide-angle lens still includes first diaphragm 180(STO), can adjust the direction of propagation of light beam through addding first diaphragm 180, is favorable to improving imaging quality. The first diaphragm 180 may be located in the optical path between the fourth lens 140 and the fifth lens 150, but the embodiment of the present invention does not limit the specific setting position of the first diaphragm 180.

The aspherical surface shape equation Z of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 satisfies:

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of y along the optical axis direction; c is 1/R, R represents the paraxial radius of curvature of the mirror surface; k is the cone coefficient; A. b, C, D, E, F is a high-order aspheric coefficient, where Z, R and y are both in mm.

Illustratively, table 2 details the aspheric coefficients of the lenses of the first embodiment in a possible implementation manner.

TABLE 2 aspheric coefficients in Wide-Angle lens

Serial number

A

B

C

D

E

F

G

1

4.45E-04

1.31E-04

1.43E-06

-5.85E-07

-2.17E-08

7.04E-09

-3.11E-10

2

-6.92E-03

3.18E-04

1.94E-04

-4.02E-05

-3.18E-06

2.01E-06

-1.79E-07

3

9.64E-03

-1.50E-03

-3.27E-04

-9.29E-05

7.15E-06

4.77E-06

-4.97E-07

4

2.58E-02

1.84E-04

-2.83E-03

3.60E-04

-1.39E-05

1.56E-05

-2.36E-06

7

-1.15E-02

3.07E-03

-5.66E-03

9.49E-04

1.09E-03

-1.86E-04

-6.18E-05

8

-1.55E-05

-7.59E-03

1.16E-03

3.05E-04

7.41E-05

-1.12E-05

-1.41E-05

10

2.00E-02

-1.46E-02

4.41E-03

-8.45E-04

8.14E-05

-1.14E-04

3.19E-05

11

-1.01E-02

-7.97E-03

3.37E-03

-1.50E-03

2.52E-04

-5.64E-06

-1.05E-06

12

-3.98E-02

-6.14E-04

3.79E-03

-1.50E-03

2.14E-04

-3.21E-06

1.07E-06

13

-2.54E-02

6.06E-03

-4.51E-04

-1.71E-06

-3.97E-06

8.71E-07

1.24E-08

14

7.76E-03

2.96E-04

-2.18E-05

7.11E-06

-1.67E-06

-4.68E-07

6.56E-08

15

9.56E-03

8.13E-04

2.84E-04

-3.12E-05

-1.94E-06

2.09E-07

-6.92E-09

Wherein 4.45E-04 denotes a coefficient A of 4.45 x 10 with a face number of 1^-3And so on.

The wide-angle lens of the first embodiment achieves the following technical indexes:

TONG diameter: n is 1.48;

aperture: f is 2.0;

TTL/BFL＝3.54；

the field angle: 2w is more than or equal to 95 degrees;

optical distortion: f-tan (theta) < 3%;

resolution ratio: can be adapted to 800 ten thousand pixel high resolution CCD or CMOS cameras.

Further, fig. 3 is a spherical aberration curve diagram of a wide-angle lens provided in the embodiment of the present invention, as shown in fig. 3, the spherical aberration of the wide-angle lens under different wavelengths (0.436 μm, 0.486 μm, 0.546 μm, 0.587 μm and 0.656 μm) is all within 0.05mm, and different wavelength curves are relatively concentrated, which indicates that the axial aberration of the wide-angle lens is very small, so that it can be known that the wide-angle lens provided in the embodiment of the present invention can better correct the aberration.

Fig. 4 is a light fan diagram of a wide-angle lens according to an embodiment of the present invention, as shown in fig. 4, imaging ranges of different wavelengths of light (0.436 μm, 0.486 μm, 0.546 μm, 0.588 μm, and 0.656 μm) at different angles of view of the wide-angle lens are all within 50 μm and curves are very concentrated, so as to ensure that aberrations of different fields of view are small, i.e., it is explained that the wide-angle lens corrects aberrations of an optical system well.

Fig. 5 is a dot-column diagram of a wide-angle lens according to a first embodiment of the present invention, as shown in fig. 5, the RMS radius of each field is smaller than 3.5 μm, which illustrates that the image quality of the wide-angle lens according to the first embodiment is high.

Fig. 6 is a vertical axis chromatic aberration of a wide-angle lens according to a first embodiment of the present invention, fig. 7 is a field curvature distortion diagram of a wide-angle lens according to a first embodiment of the present invention, fig. 8 is an MTF diagram of a wide-angle lens according to a first embodiment of the present invention, and as shown in fig. 6-8, a vertical axis chromatic aberration of a wide-angle lens according to an embodiment of the present invention is small; the field curvature is small, namely, the difference between the image quality of the center and the image quality of the periphery is small when imaging; the image quality is higher, can realize 4K high definition image quality.

Example two

With continued reference to fig. 2, a second embodiment of the present invention provides a wide-angle lens including a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged in sequence from an object plane to an image plane along an optical axis, wherein a second diaphragm 190 is disposed in an optical path between the third lens 130 and the fourth lens 140. Table 3 shows optical physical parameters such as surface type, radius of curvature, thickness, and material of each lens in the wide-angle lens provided in the second embodiment.

TABLE 3 optical physical parameters of Wide-Angle lens

Number of noodles	Surface type	Radius of curvature	Thickness of	Material (nd)	Coefficient of K
						1	Aspherical surface	-20.9	0.6	1.53	-172.5
2	Aspherical surface	3.6	0.4		0.16
						3	Aspherical surface	3.4	1.1	1.66	0.9
4	Aspherical surface	3.1	1.0		1.1
						5	Aspherical surface	-8.1	1.1	1.66	-0.0023
6	Aspherical surface	-5.1	0.2		-38.4
						STO	PL	Infinity	0.03
8	Aspherical surface	34.4	0.9	1.53	-0.2
						9	Aspherical surface	-8.5	0.04		-0.00036
10	Spherical surface	-9.3	1.3	1.69	10.9
						11	Spherical surface	-2.6	0.1		-6.8
12	Aspherical surface	5.4	0.5	1.67	-49.3
						13	Aspherical surface	2.0	0.3		-8.3
14	Non-ballNoodle	-13.5	1.6	1.53	30.4
						15	Aspherical surface	-2.2	2.8		-0.8

surface numbers

Based on the above implementation, optionally, the fifth lens 150 is a glass aspheric lens, and the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the sixth lens 160, and the seventh lens 170 are all plastic aspheric lenses. The embodiment of the utility model provides a wide-angle lens still includes second diaphragm 190(STO), can adjust the direction of propagation of light beam through addding second diaphragm 190, is favorable to improving imaging quality. The second diaphragm 190 may be located in the optical path between the third lens 130 and the fourth lens 140, but the embodiment of the present invention does not limit the specific setting position of the second diaphragm 190.

Table 4 illustrates aspheric coefficients of each lens in the second embodiment in a possible implementation manner.

TABLE 4 aspheric coefficients in Wide-Angle lens

Wherein 2.84E-03 indicates that the coefficient A with the surface number of 1 is 2.84 x 10^-3And so on.

The wide-angle lens of the second embodiment achieves the following technical indexes:

TONG diameter: n is 1.5;

aperture: f is 2.0;

TTL/BFL＝3.17；

the field angle: 2w is more than or equal to 95 degrees;

optical distortion: f-tan (theta) < 3%;

Further, fig. 9 is a spherical aberration curve diagram of a wide-angle lens provided by embodiment two of the present invention, as shown in fig. 9, the spherical aberration of the wide-angle lens under different wavelengths (0.436 μm, 0.486 μm, 0.546 μm, 0.587 μm and 0.656 μm) is all within 0.05mm, and different wavelength curves are relatively concentrated, which indicates that the axial aberration of the wide-angle lens is very small, thereby knowing that the wide-angle lens provided by the embodiment of the present invention can better correct the aberration.

Fig. 10 is a light fan diagram of a wide-angle lens according to the second embodiment of the present invention, as shown in fig. 10, imaging ranges of different wavelengths of light (0.436 μm, 0.486 μm, 0.546 μm, 0.588 μm, and 0.656 μm) at different angles of view of the wide-angle lens are all within 50 μm and curves are very concentrated, so as to ensure that aberrations of different fields of view are small, i.e., it is explained that the wide-angle lens corrects aberrations of the optical system well.

Fig. 11 is a dot-column diagram of a wide-angle lens according to a second embodiment of the present invention, as shown in fig. 11, the RMS radius of each field is smaller than 3.5 μm, which illustrates that the wide-angle lens according to the second embodiment has a higher image quality.

Fig. 12 is a vertical axis chromatic aberration of a wide-angle lens provided by the second embodiment of the present invention, fig. 13 is a field curvature distortion diagram of a wide-angle lens provided by the second embodiment of the present invention, fig. 14 is an MTF diagram of a wide-angle lens provided by the second embodiment of the present invention, and as shown in fig. 12-14, the vertical axis chromatic aberration of a wide-angle lens provided by the second embodiment of the present invention is small; the field curvature is small, namely, the difference between the image quality of the center and the image quality of the periphery is small when imaging; the image quality is higher, can realize 4K high definition image quality.

To sum up, the embodiment of the utility model provides a wide-angle lens has realized low cost, the superelevation is clear, the ultra-low distortion just does not have the wide angle prime lens of obvious purple limit, and the design adopts 7 chip type structures, under the lower prerequisite of cost, can realize 4K high definition image quality, and optical distortion accomplishes below 3%, and the angle of vision satisfies 80-100, and seven lens adopt the mixed structure of glass-plastic to make wide-angle lens can satisfy the demand that does not run burnt under-20 ℃ -60 ℃ of environment.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. A wide-angle lens is characterized by comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from an object plane to an image plane along an optical axis;

2. the wide-angle lens of claim 1, wherein the second lens is a negative power lens; the third lens is a glass spherical lens, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all plastic aspheric lenses; the wide-angle lens further comprises a first diaphragm, and the first diaphragm is arranged in an optical path between the fourth lens and the fifth lens;

3. The wide-angle lens of claim 1, wherein the first lens has a refractive index of n 1; the refractive index of the second lens is n2, and the Abbe number is v 2; the refractive index of the third lens is n3, and the Abbe number is v 3; the refractive index of the fourth lens is n4, and the Abbe number is v 4; the refractive index of the seventh lens is n 7; wherein:

4. the wide-angle lens of claim 1, wherein the rise of the object-side surface of the first lens is SAG11 and the rise of the image-side surface of the first lens is SAG12, wherein 0.08 ≦ SAG11/SAG12 ≦ 1.5.

5. The wide-angle lens of claim 1, wherein the radius of curvature of the object-side surface of the second lens is R21, where R21| ≧ 1.42.

6. The wide-angle lens of claim 1, wherein the fourth lens has a center thickness of CT4 and the fifth lens has a center thickness of CT5, wherein | CT4/CT5| ≦ 1.88.

7. The wide-angle lens of claim 1, wherein the radius of curvature of the object-side surface of the fifth lens is R51, and the radius of curvature of the image-side surface of the fifth lens is R52, wherein | R51/R52| ≧ 2.23.

8. The wide-angle lens of claim 1, wherein the fourth lens is a meniscus lens.

9. The wide-angle lens of claim 1, wherein a distance between an optical axis center of an image-side surface of the seventh lens and the image plane is BFL, and a distance between an optical axis center of an object-side surface of the first lens and the image plane is TTL, wherein BFL/TTL is 0.11 or more and 0.89 or less.

10. The wide-angle lens of claim 1, wherein the aperture of the wide-angle lens is F, wherein F/F is 0.6 ≦ F ≦ 2.8.