CN221056744U - Day and night confocal lens - Google Patents

Abstract

The utility model relates to the field of optical lenses, in particular to a day and night confocal lens which sequentially comprises the following components from an object side to an image side along an optical axis: a first lens having negative power and being a convex-concave lens; a second lens having negative power and being a convex-concave lens; the third lens is provided with positive focal power, and the object side surface of the third lens is a convex surface; a fourth lens having positive optical power; a fifth lens having negative optical power; the fourth lens and the fifth lens form a cemented lens; a sixth lens having positive power and being a convex lens; a seventh lens having positive optical power; the first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens and the seventh lens are plastic aspheric lenses; the relation is satisfied: the content of F/F45 is more than or equal to 0.2 and less than or equal to 0.35. Through adopting 7 lenses and carrying out corresponding design to each lens for the camera lens has big angle of view, big formation of image target surface and little distortion, has reduced the later stage and has corrected the distortion degree of difficulty, and confocal performance is good night and day simultaneously.

Description

Day and night confocal lens

Technical Field

The utility model relates to the technical field of optical lenses, in particular to a day-night confocal lens.

Background

Along with the development of society, law enforcement departments also consider the process of events when guaranteeing people's property safety, because place and situation that the event takes place are indefinite, so also need more and more to law enforcement appearance, not only need be suitable for daytime and night scene, but also should have good imaging quality at different temperatures, but the law enforcement appearance camera lens on the market does not possess day night confocal performance in many, can appear the condition of virtual focus in actual shooting process, is difficult to satisfy daily use's demand.

Disclosure of utility model

In view of the defects and shortcomings of the prior art, the utility model provides a day-night confocal lens, which is characterized in that a lens consisting of seven lenses is adopted, lens parameters are limited to ensure that the field angle FOV is more than or equal to 125 degrees, the TTL is less than or equal to 18.6, and the day-night confocal lens with large field angle, large target surface and low distortion is realized.

In order to achieve the above purpose, the main technical scheme adopted by the utility model comprises the following steps:

the day and night confocal lens sequentially comprises the following components from an object side to an image side along an optical axis:

the first lens has negative focal power and is a convex-concave lens;

The second lens is provided with negative focal power and is a convex-concave lens;

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

A fourth lens having positive optical power;

a fifth lens having negative optical power;

the fourth lens and the fifth lens form a cemented lens;

the sixth lens is provided with positive focal power and is a convex lens;

A seventh lens having positive optical power;

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 aspherical lenses;

The lens satisfies the following relation:

0.2≤|F/F45|≤0.35；

Wherein F is the effective focal length of the lens, and F45 is the focal length of the cemented lens formed by the fourth lens and the fifth lens.

By adopting 7 lenses, wherein 2 glass spherical lenses and 5 plastic aspherical lenses are combined, and simultaneously the fourth lens and the fifth lens are used as a cementing lens, and the lenses are correspondingly designed, the whole lens has a large field angle and a large imaging target surface and also has small distortion, and the lens has the advantage of reducing the difficulty of post-correction distortion; meanwhile, the day-night confocal function of the lens can ensure that the lens has better imaging quality under the condition of switching between daytime and night, is not easy to lose focus in the temperature range of-20 ℃ to 60 ℃, and has stable imaging quality.

Further, the lens satisfies the following relation:

2.0≤Fno≤2.4；

Wherein FNo is the aperture size of the day-night confocal lens.

By satisfying the above relation, the selectivity of different lens aperture sizes for the environment is increased.

Further, the lens satisfies the following relation:

Nd4<Nd5，Vd4>Vd5；

Wherein Nd4 is the refractive index of the fourth lens in the cemented lens, vd4 is the abbe number of the fourth lens in the cemented lens, nd5 is the refractive index of the fifth lens in the cemented lens, and Vd5 is the abbe number of the fifth lens in the cemented lens.

By satisfying the relation, the transverse phase difference is corrected, and the performance is further improved.

Further, the lens satisfies the following relation:

18<DFOV/ImgH<19.5；

wherein DFOV is the diagonal imaging angle of the lens and ImgH is the diagonal imaging diameter of the lens.

By satisfying the relation, the lens design with a large wide angle and a large target surface is realized.

Further, the lens satisfies the following relation:

2≤CT4/CT5≤4.5；

wherein, CT4 is the center thickness of the fourth lens, and CT5 is the center thickness of the fifth lens.

By satisfying the relation, the manufacturing difficulty of the glued lens is reduced.

Further, the lens satisfies the following relation:

1≤CT6/CT7≤2；

Wherein, CT6 is the center thickness of the sixth lens, and CT7 is the center thickness of the seventh lens.

The light beam can smoothly move in the latter half part by meeting the relation, and the performance is further improved.

Further, the lens satisfies the following relation:

1.5≤|F3/F1|≤2；

Wherein F3 is the focal length of the third lens, and F1 is the focal length of the first lens.

Further, the lens satisfies the following relation:

0.09≤F/TTL≤0.1；

Wherein TTL is the total length from the object side surface to the image side surface of the first lens of the lens.

The beneficial effects of the utility model are as follows:

According to the day and night confocal lens, 7 lenses are adopted, wherein 2 glass spherical lenses and 5 plastic aspherical lenses are combined, meanwhile, the fourth lens and the fifth lens are used as a cemented lens, and the lenses are correspondingly designed, so that the whole lens has a large field angle and a large imaging target surface and also has small distortion, and the advantage of reducing the later distortion correction difficulty is achieved; meanwhile, the day-night confocal function of the lens can ensure that the lens has better imaging quality under the condition of switching between daytime and night, is not easy to lose focus in the temperature range of-20 ℃ to 60 ℃, and has stable imaging quality.

Drawings

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

FIG. 2 is a graph of defocus (60 lp/mm) at 435-650nm for visible light of example 1 of the present utility model;

FIG. 3 is a graph of defocus (60 lp/mm) at low temperature (-20deg.C) for example 1 of the present utility model at 435-650nm in visible light;

FIG. 4 is a graph of defocus (60 lp/mm) at high temperature (60 ℃ C.) for example 1 of the present utility model at 435-650nm in visible light;

FIG. 5 is a defocus plot (60 lp/mm) at 850nm for IR light for example 1 of the present utility model;

FIG. 6 is a dot column diagram of example 1 of the present utility model at 435-650nm in visible light;

FIG. 7 is a graph showing the field curvature at 435-650nm in the visible light range of example 1 of the present utility model;

FIG. 8 is a graph showing distortion at 435-650nm in visible light for example 1 of the present utility model;

FIG. 9 is a schematic diagram of the structure of embodiment 2 of the present utility model;

FIG. 10 is a graph of defocus (60 lp/mm) at 435-650nm for visible light of example 2 of the present utility model;

FIG. 11 is a graph of defocus (60 lp/mm) at low temperature (-20deg.C) for visible light 435-650nm for example 2 of the present utility model;

FIG. 12 is a graph of defocus (60 lp/mm) at high temperature (60 ℃ C.) for visible light 435-650nm for example 2 of the present utility model;

FIG. 13 is a defocus plot (60 lp/mm) at 850nm for IR light for example 2 of the present utility model;

FIG. 14 is a dot column diagram at 435-650nm of visible light according to example 2 of the present utility model;

FIG. 15 is a graph showing the field curvature at 435-650nm for visible light in example 2 of the present utility model;

FIG. 16 is a graph showing distortion at 435-650nm for visible light in example 2 of the present utility model;

FIG. 17 is a schematic diagram of the structure of embodiment 3 of the present utility model;

FIG. 18 is a graph of defocus (60 lp/mm) at 435-650nm for visible light of example 3 of the present utility model;

FIG. 19 is a graph of defocus (60 lp/mm) at low temperature (-20deg.C) for visible light 435-650nm for example 3 of the present utility model;

FIG. 20 is a graph of defocus (60 lp/mm) at high temperature (60 ℃ C.) for example 3 of the present utility model at 435-650nm in visible light;

FIG. 21 is a defocus plot (60 lp/mm) at 850nm for IR light for example 3 of the present utility model;

FIG. 22 is a dot column diagram at 435-650nm of visible light according to example 3 of the present utility model;

FIG. 23 is a graph showing the field curvature at 435-650nm for visible light in example 3 of the present utility model;

FIG. 24 is a graph showing distortion at 435-650nm in the visible light of example 3 of the present utility model.

In the figure: the first lens L1, the second lens L2, the third lens L3, the aperture stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the filter I8.

Detailed Description

The utility model will be better explained by the following detailed description of the embodiments with reference to the drawings.

The day and night confocal lens provided by the embodiment of the utility model sequentially comprises the following components from an object side to an image side along an optical axis:

a first lens L1 having negative optical power, the first lens L1 being a convex-concave lens;

a second lens L2 having negative optical power, the second lens L2 being a convex-concave lens;

the third lens L3 has positive focal power, and the object side surface of the third lens L3 is a convex surface;

a fourth lens L4 having positive optical power;

A fifth lens L5 having negative optical power;

the fourth lens L4 and the fifth lens L5 form a cemented lens;

a sixth lens L6 having positive optical power, the sixth lens L6 being a convex lens;

a seventh lens L7 having positive optical power;

The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are plastic aspherical lenses;

The lens satisfies the following relation:

0.2≤|F/F45|≤0.35；

Wherein F is the effective focal length of the lens, and F45 is the focal length of the cemented lens formed by the fourth lens L4 and the fifth lens L5.

By adopting 7 lenses, wherein 2 glass spherical lenses and 5 plastic aspherical lenses are combined, and simultaneously the fourth lens L4 and the fifth lens L5 are used as cemented lenses, and the lenses are correspondingly designed, the whole lens has a large field angle and a large imaging target surface, and simultaneously has small distortion, and the lens has the advantage of reducing the later-stage distortion correction difficulty; meanwhile, the day-night confocal function of the lens can ensure that the lens has better imaging quality under the condition of switching between daytime and night, is not easy to lose focus in the temperature range of-20 ℃ to 60 ℃, and has stable imaging quality.

Specifically, the lens satisfies the following relation:

2.0≤Fno≤2.4；

Wherein FNo is the aperture size of the day-night confocal lens.

By satisfying the above relation, the selectivity of different lens aperture sizes for the environment is increased.

Specifically, the lens satisfies the following relation:

Nd4<Nd5，Vd4>Vd5；

Wherein Nd4 is the refractive index of the fourth lens L4 in the cemented lens, vd4 is the abbe number of the fourth lens L4 in the cemented lens, nd5 is the refractive index of the fifth lens L5 in the cemented lens, and Vd5 is the abbe number of the fifth lens L5 in the cemented lens.

By satisfying the relation, the transverse phase difference is corrected, and the performance is specifically improved.

Specifically, the lens satisfies the following relation:

18<DFOV/ImgH<19.5；

wherein DFOV is the diagonal imaging angle of the lens and ImgH is the diagonal imaging diameter of the lens.

By satisfying the relation, the lens design with a large wide angle and a large target surface is realized.

Specifically, the lens satisfies the following relation:

2≤CT4/CT5≤4.5；

Wherein, CT4 is the center thickness of the fourth lens L4, and CT5 is the center thickness of the fifth lens L5.

By satisfying the relation, the manufacturing difficulty of the glued lens is reduced.

Specifically, the lens satisfies the following relation:

1≤CT6/CT7≤2；

Wherein, CT6 is the center thickness of the sixth lens L6, and CT7 is the center thickness of the seventh lens L7.

The light beam is favorable for smooth trend of the light beam in the latter half part by meeting the relation, and the performance is particularly improved.

Specifically, the lens satisfies the following relation:

1.5≤|F3/F1|≤2；

wherein F3 is the focal length of the third lens L3, and F1 is the focal length of the first lens L1.

Specifically, the lens satisfies the following relation:

0.09≤F/TTL≤0.1；

Wherein TTL is the total length from the object side surface to the image plane of the first lens L1 of the lens.

In order that the above-described aspects may be better understood, exemplary embodiments of the present utility model will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present utility model are shown in the drawings, it should be understood that the present utility model may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the utility model to those skilled in the art.

Example 1

The present embodiment provides a day-night confocal lens, which is composed of a first lens L1, a second lens L2, a third lens L3, an aperture stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter I8 in order from the object side to the image side along the optical axis. The first lens L1 has negative focal power and is a convex-concave lens, the second lens L2 has negative focal power and is a convex-concave lens, the third lens L3 has positive focal power and is a convex-concave lens, the fourth lens L4 has positive focal power and is a convex-convex lens, the fifth lens L5 has negative focal power and is a concave-concave lens, the bonding surface between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is a bonding surface between the fourth lens L4 and the fifth lens L5, the sixth lens L6 has positive focal power and is a convex-convex lens, the seventh lens L7 has positive focal power and is a convex-convex lens, and the optical filter I8 is arranged between the seventh lens L7 and the image surface.

The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are plastic aspherical lenses.

Table 1 shows the surface type, radius of curvature, thickness, refractive index, and dispersion coefficient of each lens in example 1. Wherein, the unit of curvature radius and thickness is millimeter (mm).

Table 1 shows the lens parameters of the lens barrel of example 1

In this embodiment, all aspherical lenses follow the formula:

Where r is the distance from a point on the optical surface to the optical axis, Z is the sagittal height of the point along the optical axis, C is the curvature of the surface, and K is the conic constant of the surface. A4, A6, A8, a10, a12, a14, a16 are aspherical coefficients of fourth order, sixth order, eighth order, tenth order, fourteen order, sixteen order, respectively.

Table 2 below shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 1.

Table 2 shows the higher order coefficients of the aspherical mirror surfaces of example 1

K

A4

A6

A8

A10

A12

A14

A16

S3

0.02

-1.09862E-0

3-6.74603E-0

48.83023E-0

5-5.60644E-0

62.03899E-0

7-4.20064E-0

93.91658E-1

S4

-0.95

5.66510E-0

4-1.79402E-0

4-3.47185E-0

4-7.01996E-0

55.75294E-0

5-8.53947E-0

63.96404E-0

S8

-1.00

-1.59652E-0

27.44712E-0

2-2.92502E-0

15.67958E-0

1-5.57812E-0

12.31012E-0

1-1.61123E-0

S9

0.50

-3.22092E-0

16.75458E-0

1-7.86677E-0

15.23261E-0

1-1.84933E-0

13.26340E-0

2-3.29565E-0

S10

-90.87

-3.11008E-0

26.47055E-0

2-5.26136E-0

22.61000E-0

2-7.75709E-0

31.26198E-0

3-8.61581E-0

S11

-28.80

-8.63457E-0

31.46093E-0

2-8.28777E-0

32.71498E-0

-5.11832E-0

45.22397E-0

5-2.24174E-0

S12

-90.44

-2.47745E-0

25.98654E-0

3-3.70221E-0

31.63128E-0

-3.82433E-0

44.47628E-0

5-2.02019E-0

S13

-72.47

-1.96868E-0

3-1.47509E-0

3-6.65303E-0

42.16681E-0

4-1.79857E-0

5-2.05254E-0

62.91713E-0

S14

-0.87

1.19556E-0

2-5.23891E-0

4-5.66571E-0

44.95339E-0

51.08226E-0

5-2.41018E-0

61.40767E-0

The relevant important parameters in example 1 are shown in table 7 below.

The specific lens structure of this embodiment is shown in fig. 1.

The defocusing curves under the visible light and the infrared light are shown in figures 2 and 5 in detail, and the fact that under the condition of 60lp/mm, the visible light and the infrared light are not easy to be defocused when being switched can be seen, and the imaging quality is almost unchanged.

The defocusing curves in the low-temperature environment and the high-temperature environment are shown in figures 3 and 4, and the fact that the defocusing is difficult to occur in the temperature range of-20 ℃ to 60 ℃ under the condition of 60lp/mm can be seen, and the imaging quality is stable.

The point diagram is shown in detail in fig. 6, and it can be seen that the aberration is small and the imaging quality is good.

The field curvature and distortion curve diagrams are shown in fig. 7-8, so that the distortion correction is better, and the difficulty of later distortion correction is reduced.

Example 2

The present embodiment provides a day-night confocal lens, which is composed of a first lens L1, a second lens L2, a third lens L3, an aperture stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter I8 in order from the object side to the image side along the optical axis. The first lens L1 has negative focal power and is a convex-concave lens, the second lens L2 has negative focal power and is a convex-concave lens, the third lens L3 has positive focal power and is a convex-concave lens, the fourth lens L4 has positive focal power and is a convex-convex lens, the fifth lens L5 has negative focal power and is a concave-concave lens, the bonding surface between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is a bonding surface between the fourth lens L4 and the fifth lens L5, the sixth lens L6 has positive focal power and is a convex-convex lens, the seventh lens L7 has positive focal power and is a convex-convex lens, and the optical filter I8 is arranged between the seventh lens L7 and the image surface.

The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are plastic aspherical lenses.

Table 3 shows the surface form, radius of curvature, thickness, refractive index, and dispersion coefficient of each lens in example 2. Wherein, the unit of curvature radius and thickness is millimeter (mm).

Table 3 shows the lens parameters of the lens barrel of example 2

In the present embodiment, each aspherical surface profile may be defined by the formula (1) in the above embodiment 1.

Table 4 below shows the higher order coefficients that can be used for each of the aspherical mirrors in example 2.

Table 4 shows the higher order coefficients of the aspherical mirror surfaces of example 2

K

A4

A6

A8

A10

A12

A14

A16

S3

0.01

-7.66917E-04

-8.86389E-04

1.37271E-04

-1.09959E-05

5.12710E-07

-1.31774E-08

1.44624E-10

S4

-0.93

4.16501E-03

9.32521E-04

-2.60405E-03

1.01393E-03

-1.78030E-04

1.56821E-05

-5.44584E-07

S8

-1.00

-2.22895E-02

9.82302E-02

-3.09672E-01

5.74108E-01

-6.48701E-01

4.15468E-01

-1.14046E-01

S9

0.80

-3.27372E-01

1.20847E+00

-2.37790E+00

2.62628E+00

-1.52702E+00

3.82103E-01

-1.81771E-02

S10

-90.87

-4.25776E-02

8.90562E-02

-1.00294E-01

6.70802E-02

-2.64117E-02

5.60802E-03

-4.93555E-04

S11

-25.62

-5.90218E-03

1.46424E-02

-1.09723E-02

4.60325E-03

-1.09878E-03

1.40964E-04

-7.52137E-06

S12

-90.44

-1.73213E-02

-3.76382E-03

1.86912E-03

2.07279E-04

-1.87342E-04

3.43374E-05

-2.02019E-06

S13

-72.47

1.02584E-03

-5.20623E-03

1.06453E-03

-2.89426E-04

8.52168E-05

-1.42967E-05

8.85736E-07

S14

-0.87

1.41725E-02

-1.97453E-03

1.52332E-04

-1.59562E-04

5.11073E-05

-6.51748E-06

2.99707E-07

The relevant important parameters in example 2 are shown in table 7 below.

A specific lens structure of this embodiment is shown in fig. 9.

The defocusing curves under the visible light and the infrared light are shown in fig. 10 and 13, and it can be seen that under the condition of 60lp/mm, the visible light and the infrared light are not easy to be defocused when being switched, and the imaging quality is almost unchanged.

The defocusing curves in the low-temperature environment and the high-temperature environment are shown in figures 11 and 12, and the fact that the defocusing is difficult to occur in the temperature range of-20 ℃ to 60 ℃ under the condition of 60lp/mm can be seen, and the imaging quality is stable.

The point diagram is shown in detail in fig. 14, and it can be seen that the aberration is small and the imaging quality is good.

The field curvature and distortion curve diagrams are shown in fig. 15 and 16, so that the distortion correction is better, and the difficulty of later distortion correction is reduced.

Example 3

The present embodiment provides a day-night confocal lens, which is composed of a first lens L1, a second lens L2, a third lens L3, an aperture stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter I8 in order from the object side to the image side along the optical axis. The first lens L1 has negative focal power and is a convex-concave lens, the second lens L2 has negative focal power and is a convex-concave lens, the third lens L3 has positive focal power and is a convex-convex lens, the fourth lens L4 has positive focal power and is a convex-convex lens, the fifth lens L5 has negative focal power and is a concave-concave lens, the bonding surface A between the image side surface of the fourth lens L4 and the object side surface of the fifth lens L5 is a bonding surface A between the fourth lens L4 and the fifth lens L5, the sixth lens L6 has positive focal power and is a convex-convex lens, the seventh lens L7 has positive focal power and is a convex-convex lens, and the optical filter I8 is arranged between the seventh lens L7 and the image surface.

The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are plastic aspherical lenses.

Table 5 shows the surface shape, radius of curvature, thickness, refractive index, and dispersion coefficient of each lens in example 3. Wherein, the unit of curvature radius and thickness is millimeter (mm).

Table 5 is a table of lens parameters of the lens barrel of example 3

In the present embodiment, each aspherical surface profile may be defined by the formula (1) in the above embodiment 1.

Table 6 below shows the higher order coefficients that can be used for each of the aspherical mirrors in example 3.

Table 6 shows the higher order coefficients of the aspherical mirror surfaces of example 3

K

A4

A6

A8

A10

A12

A14

A16

S3

-0.06

-7.47709E-04

-8.78702E-04

1.34771E-04

-1.06036E-05

4.76118E-07

-1.15602E-08

1.17945E-10

S4

-0.92

5.53301E-03

5.06050E-04

-2.25528E-03

8.93033E-04

-1.51779E-04

1.19191E-05

-3.10406E-07

S8

-1.00

-2.29360E-02

1.49168E-01

-5.47459E-01

1.12345E+00

-1.29497E+00

7.87264E-01

-1.95994E-01

S9

1.29

-2.79731E-01

9.58623E-01

-1.76187E+00

1.84128E+00

-1.07427E+00

2.97469E-01

-2.50830E-02

S10

-90.87

-3.01387E-02

6.65678E-02

-7.44744E-02

4.86258E-02

-8.96376E-02

4.07355E-03

-3.68825E-04

S11

-17.39

8.69699E-04

5.17684E-03

-3.90562E-03

1.41851E-03

-2.79151E-04

3.10332E-05

-1.40606E-06

S12

-90.44

-2.13211E-02

-4.73092E-03

3.11322E-03

-4.07520E-04

-8.56430E-05

2.81697E-05

-2.02019E-06

S13

-72.47

3.49034E-03

-7.07261E-03

-4.91746E-04

8.46062E-04

-1.82339E-04

1.31226E-05

-1.55030E-07

S14

-1.30

2.03711E-02

-2.80797E-03

-1.97944E-03

9.49539E-04

-1.72242E-04

1.41869E-05

-4.41621E-07

The relevant important parameters in example 3 are shown in table 7 below.

A specific lens structure of this embodiment is shown in fig. 17.

The defocusing curves under the visible light and the infrared light are shown in fig. 18 and 21, and it can be seen that under the condition of 60lp/mm, the visible light and the infrared light are not easy to be defocused when being switched, and the imaging quality is almost unchanged.

The defocusing curves in the low-temperature environment and the high-temperature environment are shown in figures 19 and 20, and the fact that the defocusing is difficult to occur in the temperature range of-20 ℃ to 60 ℃ under the condition of 60lp/mm can be seen, and the imaging quality is stable.

The point diagram is shown in detail in fig. 22, and it can be seen that the aberration is small and the imaging quality is good.

The field curvature and distortion curve diagrams are shown in fig. 23 and 24, so that the distortion correction is better, and the difficulty of later distortion correction is reduced.

Table 7 below shows the values of the important parameters for three examples in the detailed description.

Table 7 is a table of important parameters.

	Example 1	Example two	Example III
				Fno	2.4	2	2.2
TTL	18.6	18.6	18.6
				DFOV	130	135	140
ImgH	7.1	7.18	7.26
				F	1.76	1.88	1.96
F1	-12.13	-15.26	-16.85
				F2	-3.01	-2.99	-3.23
F3	4.41	4.43	4..82
				F45	-5.58	-5.88	-8.61
F6	3.77	3.68	3.98
				F7	4.80	5.38	7.15

While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that alterations, modifications, substitutions and variations may be made in the above embodiments by those skilled in the art within the scope of the utility model.

Claims (8)

1. A day-night confocal lens, characterized by comprising, in order from an object side to an image side along an optical axis:

the first lens has negative focal power and is a convex-concave lens;

The second lens is provided with negative focal power and is a convex-concave lens;

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

A fourth lens having positive optical power;

a fifth lens having negative optical power;

the fourth lens and the fifth lens form a cemented lens;

the sixth lens is provided with positive focal power and is a convex lens;

A seventh lens having positive optical power;

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 aspherical lenses;

The lens satisfies the following relation:

0.2≤|F/F45|≤0.35；

Wherein F is the effective focal length of the lens, and F45 is the focal length of the cemented lens formed by the fourth lens and the fifth lens.

2. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

2.0≤Fno≤2.4；

Wherein FNo is the aperture size of the day-night confocal lens.

3. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

Nd4<Nd5，Vd4>Vd5；

Wherein Nd4 is the refractive index of the fourth lens in the cemented lens, vd4 is the abbe number of the fourth lens in the cemented lens, nd5 is the refractive index of the fifth lens in the cemented lens, and Vd5 is the abbe number of the fifth lens in the cemented lens.

4. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

18<DFOV/ImgH<19.5；

wherein DFOV is the diagonal imaging angle of the lens and ImgH is the diagonal imaging diameter of the lens.

5. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

2≤CT4/CT5≤4.5；

wherein, CT4 is the center thickness of the fourth lens, and CT5 is the center thickness of the fifth lens.

6. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

1≤CT6/CT7≤2；

Wherein, CT6 is the center thickness of the sixth lens, and CT7 is the center thickness of the seventh lens.

7. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

1.5≤|F3/F1|≤2；

Wherein F3 is the focal length of the third lens, and F1 is the focal length of the first lens.

8. The day-night confocal lens of claim 1 wherein said lens satisfies the following relationship:

0.09≤F/TTL≤0.1；

Wherein TTL is the total length from the object side surface to the image side surface of the first lens of the lens.