CN209946508U

CN209946508U - Multipurpose miniaturized fisheye lens

Info

Publication number: CN209946508U
Application number: CN201920963020.7U
Authority: CN
Inventors: 吴冬芹; 张云涛; 寿志豪; 尚洁阳; 张�杰
Original assignee: Jiaxing Zhongrun Optical Technology Co Ltd
Current assignee: Jiaxing Zhongrun Optical Technology Co Ltd
Priority date: 2019-06-25
Filing date: 2019-06-25
Publication date: 2020-01-14
Anticipated expiration: 2029-06-25

Abstract

A multipurpose miniaturized fisheye lens includes, in order from an object side to an image side: a first lens having a negative power, a second lens having a negative power, a third lens having a positive power, a fourth lens having a positive power, a diaphragm, a fifth lens having a positive power, a sixth lens having a negative power, and a seventh lens having a positive power; the second lens and the fifth to seventh lenses are made of plastic aspheric surfaces and are reasonably matched with glass, so that the problem of focus drift of the lens used in different temperature environments is solved. The utility model discloses a reasonable focal power distribution makes camera lens super wide angle, big light ring, stereographic projection distortion little, can use under-30 ℃ -85 ℃ environment moreover, has increased the use occasion of camera lens. The total length of the optical path of the lens is short, the size is small, the back focus is large, the lens can be matched with various interfaces, and the applicability of the lens is improved.

Description

Multipurpose miniaturized fisheye lens

Technical Field

The utility model relates to a technique in the optical lens field specifically is a size is at the miniaturized fisheye lens of multipurpose about 20 mm.

Background

The fisheye lens can shoot a large-view-field environment due to the fact that the field angle generally exceeds 100 degrees, and is widely applied to occasions such as security protection, vehicle-mounted video conferences and the like. The field angle of the fish-eye lens in the current market is about 180 degrees, the f-number is generally larger than 2.0, and the problem that the field angle and the large aperture are difficult to be compatible occurs. This problem is caused by a large loss of peripheral luminance ratio with an increase in the angle of view, particularly after exceeding 180 °, and the peripheral luminance of the screen is significantly low, and the image quality is also drastically reduced. The fisheye lens applied to monitoring, vehicle-mounted or video conferences has higher requirements on thermal drift; in a low-temperature environment or a high-temperature environment, the focal plane of the lens is always kept within the tolerance range of clear picture errors. The above-mentioned defects limit the application of the fisheye lens in various fields.

SUMMERY OF THE UTILITY MODEL

The utility model discloses it is not enough to the above-mentioned that prior art exists, provides a miniaturized fisheye camera lens of multipurpose, possesses big light ring, high peripheral brightness ratio, 190 super wide angles, projection distortion little, do not have the advantage of heat drift and low cost, and this miniaturized fisheye camera lens is applicable to multiple occasion.

The utility model discloses a realize through following technical scheme:

the utility model discloses include from the thing side to picture side in proper order: the optical lens assembly includes a first lens having a negative optical power, a second lens having a negative optical power, a third lens having a positive optical power, a fourth lens having a positive optical power, a diaphragm, a fifth lens having a positive optical power, a sixth lens having a negative optical power, and a seventh lens having a positive optical power.

The ratio of the focal lengths of the first to seventh lenses to the overall focal length of the lens is as follows: (5.71,6.75), (-1.66, -0.92), (-2.16,7.68), (0.71,1.72), (-1.08,2.95), (-1.75,2.25) and (1.64, 7.65).

The ratio of the focal length of the first lens to the focal length of the third lens is [ -0.45, -0.42).

The ratio of the distance from the outermost point of the object side of the first lens to the imaging surface to the overall focal length of the lens is (0.16, 0.20).

The first lens satisfies: 40.7 < Y FOV/D < 41.1, wherein: y is the imaging height corresponding to the maximum field angle of the lens, FOV is the field angle of the lens, and D is the maximum light-passing aperture of the front convex surface facing the object side of the first lens corresponding to the maximum field angle of the lens.

Technical effects

Compared with the prior art, the utility model discloses a reasonable focal power distribution makes camera lens super wide angle, big light ring, stereographic projection distortion little, can use under-30 ℃ to 85 ℃ of environment moreover, has increased the use occasion of camera lens. The total length of the optical path of the lens is short, the size is small, the back focus is large, the lens can be matched with various interfaces, and the applicability of the lens is improved.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a graph showing color difference characteristics of example 1;

FIG. 3 is a graph showing MTF characteristics at 20 ℃ in example 1;

FIG. 4 is a graph of MTF characteristics at-30 ℃ for example 1;

FIG. 5 is a graph showing MTF characteristics at 85 ℃ in example 1;

in the figure: a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a sixth lens G6, a seventh lens G7, and a stop STP.

Detailed Description

Example 1

As shown in fig. 1, the present embodiment includes, in order from the object side to the image side: a first lens G1 having negative power, a second lens G2 having negative power, a third lens G3 having positive power, a fourth lens G4 having positive power, a stop STP, a fifth lens G5 having positive power, a sixth lens G6 having negative power, and a seventh lens G7 having positive power.

The ratio of the integral focal length to the total length of the lens is 0.084.

The ratio of the focal lengths of the first lens G1 to the seventh lens G7 to the overall focal length of the lens is as follows: -5.24, -2.01, 4.48, 3.88, 2.71, -1.63 and 2.24.

The ratio of the focal length of the first lens G1 to the focal length of the third lens G3 is-1.17.

The ratio of the focal length of the second lens G2 to the focal length of the third lens G3 is-0.45.

The second lens G2 and the fifth lens G5 to the seventh lens G7 are all plastic aspheric surfaces, wherein: the second lens G2, the fifth lens G5, and the seventh lens G7 were made of K26R, and had a refractive index of 1.535 and an abbe number of 56; the sixth lens G6 was made of EP6000 and had a refractive index of 1.639 and an abbe number of 24.

Table 1 physical parameters of each lens of example 1

Table 2 example 1 aspheric coefficients

Surface number

K

A

B

C

D

E

3

2.67

5.48E-03

-5.23E-04

3.48E-05

-9.38E-07

8.94E-09

4

1.57

5.42E-03

3.47E-03

-3.98E-04

-3.15E-05

2.02E-05

10

28.37

-3.49E-03

-4.79E-03

4.80E-03

-2.83E-03

1.70E-04

11

-2.40

3.41E-02

-3.40E-02

1.47E-02

-3.23E-03

-2.89E-05

12

-57.24

-3.48E-02

-2.88E-02

3.41E-02

-3.77E-03

3.31E-04

13

5.47

-7.82E-02

1.48E-02

-5.19E-03

6.75E-04

-1.45E-04

14

1.52

9.20E-04

3.64E-03

-2.30E-03

6.10E-04

-7.16E-05

15

2.67

1.31E-02

4.79E-03

-8.77E-06

3.56E-04

-2.41E-05

As shown in fig. 2, which is a dispersion characteristic curve and a field curvature characteristic curve of embodiment 1 of the present invention, the chromatic aberration of the system is effectively reduced and the image quality is improved by matching the high refractive index, low abbe number and low refractive index, high abbe number materials.

As shown in fig. 3 to 5, the present invention has excellent resolving power even in the low temperature and high temperature environment without the focus drift, and increases the use occasion and the environment condition of the lens.

Example 2

Compared with embodiment 1, the ratio of the overall focal length to the overall length of the lens of this embodiment is 0.085.

The ratio of the focal lengths of the first lens G1 to the seventh lens G7 to the overall focal length of the lens is as follows: -5.22, -2.05, 4.44, 3.86, 2.74, -1.64, 2.21.

The ratio of the focal length of the first lens G1 to the focal length of the third lens G3 is-1.14.

The ratio of the focal length of the second lens G2 to the focal length of the third lens G3 is-0.42.

Table 3 physical parameters of each lens of example 2

Table 4 example 2 aspheric coefficients

Surface number

K

A

B

C

D

E

3

13.47

4.98E-03

-5.48E-04

6.48E-05

-7.38E-07

7.17E-09

4

14.57

4.72E-03

6.47E-03

-2.48E-04

-2.47E-05

1.75E-05

10

26.79

-6.72E-03

-3.94E-03

5.72E-03

-1.80E-03

6.28E-04

11

-21.30

3.71E-02

-2.48E-02

2.47E-02

-2.58E-03

-5.28E-05

12

-5.70

-2.48E-02

-3.48E-02

3.48E-02

-2.48E-03

7.18E-04

13

14.82

-8.68E-02

3.48E-02

-4.80E-03

8.18E-04

-7.82E-04

14

1.67

4.79E-04

2.81E-03

-1.79E-03

5.79E-04

-8.24E-05

15

20.81

1.47E-02

6.71E-03

-6.28E-06

6.48E-04

-5.72E-05

The conic surface coefficient of the lens surface is K, the aspheric surface coefficients of fourth order, sixth order, eighth order, tenth order, twelfth order and fourteenth order are A, B, C, D, E and F respectively, the rise of one point on the aspheric surface along the optical axis direction is z, and the following requirements are met:

according to the projection distortion formula:

wherein: y is the half image height, theta is the half field angle, f is the focal length of the lens, and D is the stereographic projection distortion value. When the large target surface and the large angle are met, the projection distortion is required to be small.

Through reasonable focal power distribution, the focal power of each lens is in a reasonable interval, tolerance sensitivity is reduced to the maximum extent, especially the focal length distribution of the aspheric lens, glass and plastic are reasonably matched, and the problem of focus drift of the lens used in different temperature environments is solved.

Compared with the prior art, the utility model discloses a configuration lectotype of configuration optimization and lens material, make full use of plastics aspheric surface to the correction of aberration with the compensation that the temperature drifted when glass moulds the mixture, make the utility model discloses a not only possess super wide angle, big light ring, stereographic projection distortion little, be applicable to-30 ℃ to 85 ℃ of service environment, increased the use occasion and the environmental scope of camera lens.

The foregoing embodiments may be modified in various ways by those skilled in the art without departing from the spirit and scope of the present invention, which is not limited by the above embodiments but is to be accorded the full scope defined by the appended claims, and all such modifications and variations are within the scope of the invention.

Claims

1. A multi-purpose miniaturized fisheye lens comprising, in order from an object side to an image side: a first lens having a negative power, a second lens having a negative power, a third lens having a positive power, a fourth lens having a positive power, a diaphragm, a fifth lens having a positive power, a sixth lens having a negative power, and a seventh lens having a positive power;

the second lens and the fifth to seventh lenses are made of plastic aspheric surfaces and are reasonably matched with glass, so that the problem of focus drift of the lens used in different temperature environments is solved.

2. The multi-purpose miniaturized fish-eye lens as claimed in claim 1, wherein the ratio of the focal length of the first to seventh lenses to the overall focal length of the lens is, in order: (5.71,6.75), (-1.66, -0.92), (-2.16,7.68), (0.71,1.72), (-1.08,2.95), (-1.75,2.25) and (1.64, 7.65).

3. The multi-purpose miniaturized fish-eye lens as claimed in claim 1, wherein a ratio of a focal length of the first lens to a focal length of the third lens is [ -0.45, -0.42).

4. The multi-purpose small fisheye lens of claim 1, wherein the ratio of the distance from the outermost point of the object side of the first lens element to the image plane to the overall focal length of the lens is (0.16, 0.20).

5. The multi-purpose miniaturized fish-eye lens as claimed in claim 1, wherein the first lens satisfies: 40.7 < Y FOV/D < 41.1, wherein: y is the imaging height corresponding to the maximum field angle of the lens, FOV is the field angle of the lens, and D is the maximum light-passing aperture of the front convex surface facing the object side of the first lens corresponding to the maximum field angle of the lens.

6. The multi-purpose small fisheye lens of claim 1, wherein the second, fifth and seventh lenses are made of K26R, and have a refractive index of 1.535 and an Abbe number of 56.

7. The multi-purpose small fisheye lens of claim 1, wherein the sixth lens element is made of EP6000, and has a refractive index of 1.639 and an abbe number of 24.