CN115437114A

CN115437114A - Monitoring lens and monitoring lens module

Info

Publication number: CN115437114A
Application number: CN202211122839.3A
Authority: CN
Inventors: 刘华清; 杨东景; 王�锋; 周明明; 马庆鸿; 万良伟
Original assignee: Guangdong Xingjuyu Optical Co ltd
Current assignee: Guangdong Xingjuyu Optical Co ltd
Priority date: 2022-09-15
Filing date: 2022-09-15
Publication date: 2022-12-06

Abstract

The invention discloses a monitoring lens and a monitoring lens module, belonging to the technical field of optical imaging, and sequentially comprising the following components from an object side to an image side along an optical axis: the monitoring lens comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with positive focal power and a fourth lens with negative focal power, and the monitoring lens meets the following conditional expression: 2.3 & ltttl/f & lt 4.5;2.5 are woven into TTL/(CT 3+ CT 4) <5. The monitoring lens and the monitoring lens module provided by the invention meet the condition that the focal length of the monitoring lens with a certain total length is lengthened, the working range of the monitoring lens is improved, and the monitoring lens still keeps high-quality imaging in a larger range. Meanwhile, the proportion of the third lens and the fourth lens in the total length of the monitoring lens is restrained, system aberration is compensated, and imaging quality of the monitoring lens is improved.

Description

Monitoring lens and monitoring lens module

Technical Field

The invention relates to the technical field of optical imaging, in particular to a monitoring lens and a monitoring lens module.

Background

In recent years, with the increasing progress of digital imaging technology, lenses are widely used in the field of case monitoring. With the increasing demand of the monitoring lens, the requirements on the imaging quality and the production yield of the monitoring lens are higher and higher. At present, for a monitoring lens with a certain length, the working range is insufficient, the imaging quality is not high, and the two monitoring lenses are difficult to meet at the same time, so that a monitoring lens meeting the requirements at the same time is necessary to be designed.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a monitoring lens and a monitoring lens module, which meet the requirements of large working range and high imaging quality.

In a first aspect, a monitoring lens, in order from an object side to an image side along an optical axis, includes:

a first lens having a negative optical power, an image-side surface of which is concave near an optical axis;

a second lens having a positive refractive power, an image-side surface of which is convex near the optical axis;

a third lens having positive optical power, an image-side surface of which is convex near the optical axis; and

a fourth lens having a negative optical power, an object-side surface of which is concave near the optical axis;

the monitoring lens meets the following conditional expression:

2.3<TTL/f<4.5；

2.5<TTL/(CT3+CT4)<5；

wherein, TTL is a distance on the optical axis from the object side surface of the first lens element to the imaging surface of the monitoring lens element, f is a total effective focal length of the monitoring lens element, CT3 is a central thickness of the third lens element on the optical axis, and CT4 is a central thickness of the fourth lens element on the optical axis.

Optionally, the monitoring lens satisfies the following conditional expression:

0.9<f×tan(Semi-Fov)/ImgH<1.1；

wherein f is the total effective focal length of the monitoring lens, semi-Fov is half of the maximum field angle of the monitoring lens, and ImgH is the maximum image height of the monitoring lens.

Optionally, the monitoring lens satisfies the following conditional expression:

1.8<f12/(T12-T23)<2.7；

wherein f12 is a combined focal length of the first lens and the second lens, T12 is an air separation distance of the first lens and the second lens on the optical axis, and T23 is an air separation distance of the second lens and the third lens on the optical axis.

Optionally, the monitoring lens satisfies the following conditional expression:

0.6<BFL/f<0.9；

and the BFL is an optical back focus of the monitoring lens, and the f is a total effective focal length of the monitoring lens.

Optionally, the monitoring lens satisfies the following conditional expression:

2.2<(R11+R12)/(R11-R12)<3.2；

wherein R11 is a radius of curvature of the object-side surface of the first lens; r12 is the radius of curvature of the image-side surface of the first lens element.

Optionally, the monitoring lens satisfies the following conditional expression:

0.8<ImgH/EPD<1.5；

wherein ImgH is the maximum image height of the monitoring lens, and EPD is the entrance pupil diameter of the monitoring lens.

Optionally, the monitoring lens satisfies the following conditional expression:

0.2<SAG11/DT11<0.8

SAG11 is the distance from the intersection point of the object side surface of the first lens and the optical axis to the effective radius vertex of the object side surface of the first lens on the optical axis, and DT11 is the maximum effective radius of the object side surface of the first lens.

Optionally, the monitoring lens satisfies the following conditional expression:

|Dist.|<13.5％；

and Dist is the maximum optical distortion of the monitoring lens.

Optionally, a material of the first lens is the same as a material of the third lens.

In a second aspect, a monitoring lens module is provided, which includes the monitoring lens in any one of the possible implementation manners of the first aspect.

The invention has the beneficial effects that:

according to the given relational expression and range in the summary of the invention, 2.3 & lt TTL/f <4.5,2.5 & lt ttl/(CT 3+ CT 4) <5;

the monitoring lens with a certain total length is prolonged by adjusting the focal length within the range of 2.3 TTL/f <4.5, so that the working range of the monitoring lens is effectively improved, and the monitoring lens still keeps high-quality imaging within a larger range. Meanwhile, under the range of 2.5 ttl/(CT 3+ CT 4) <5, the proportion of the third lens and the fourth lens in the total length of the monitoring lens is restrained, so that system aberration is compensated, and the imaging quality of the monitoring lens is improved.

Drawings

Fig. 1 is a schematic structural diagram of a monitoring lens according to a first embodiment of the present application;

fig. 2 to 5 are a spherical aberration graph, an astigmatism graph, a distortion graph and a magnification chromatic aberration graph of a monitoring lens according to an embodiment of the present application in sequence;

fig. 6 is a schematic structural diagram of a monitoring lens according to a second embodiment of the present application;

fig. 7 to 10 are a spherical aberration graph, an astigmatism graph, a distortion graph and a magnification chromatic aberration graph of a second monitoring lens according to an embodiment of the present application in sequence;

fig. 11 is a schematic structural view of a monitoring lens according to a third embodiment of the present application;

fig. 12 to 15 are a spherical aberration graph, an astigmatism graph, a distortion graph and a magnification chromatic aberration graph of a third monitoring lens according to an embodiment of the present application in sequence;

fig. 16 is a schematic structural diagram of a monitoring lens according to a fourth embodiment of the present application;

fig. 17 to 20 are a spherical aberration graph, an astigmatism graph, a distortion graph and a magnification chromatic aberration graph of the four monitoring lenses according to the embodiment of the present application in sequence;

fig. 21 is a schematic structural view of a monitoring lens according to a fifth embodiment of the present application;

fig. 22 to 25 are a spherical aberration graph, an astigmatism graph, a distortion graph and a magnification chromatic aberration graph of the five monitoring lenses according to the embodiment of the present application in sequence;

fig. 26 is a schematic structural view of a monitoring lens according to a sixth embodiment of the present application;

fig. 27 to 30 are a spherical aberration diagram, an astigmatism diagram, a distortion diagram and a magnification chromatic aberration diagram of a six-monitor lens according to an embodiment of the present application.

In the figure: 100. monitoring a lens; 101. a first lens; 102. a second lens; 103. a third lens; 104. a fourth lens; 105. an optical filter; 106. an image sensor.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

For convenience of understanding, technical terms related to the present application are explained and described below.

TTL is the distance from the object side surface of the first lens to the imaging surface of the monitoring lens on the optical axis;

SAG11 is the distance on the optical axis from the intersection point of the object side surface of the first lens and the optical axis to the effective radius vertex of the object side surface of the first lens.

As shown in fig. 1, a monitoring lens 100 according to an embodiment of the present application includes 4 lenses. For convenience of description, the left side of the monitoring lens 100 is defined as an object side (hereinafter, also referred to as an object side), a surface of the lens facing the object side may be referred to as an object side surface, a surface of the monitoring lens 100 right side is defined as an image side (hereinafter, also referred to as an image side), a surface of the lens facing the image side may be referred to as an image side surface, and an image side surface may be referred to as a surface of the lens facing the image side. From the object side to the image side, the monitoring lens 100 of the embodiment of the present application sequentially includes: a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104; a stop may also be provided adjacent the object side of the first lens 101. An image sensor 106, such as a CCD, CMOS, etc., may also be disposed after the fourth lens 104. A filter 105, such as a flat infrared cut filter, may also be disposed between the fourth lens 104 and the image sensor 106. The monitor lens 100 is described in detail below.

It should be noted that, for convenience of understanding and description, the embodiment of the present application defines a representation form of relevant parameters of the monitoring lens, for example, TTL represents a distance from an object side surface of the first lens element to an imaging surface of the monitoring lens on an optical axis; imgH represents the maximum image height of the monitoring lens, and the letter representation of similar definition is only schematic, but can be represented in other forms, and the application is not limited in any way.

It should be noted that the units of the parameters related to the ratio in the following relational expression are consistent, for example, the units of numerator are millimeters (mm), and the units of denominator are also millimeters (mm).

In addition, the positive and negative of the curvature radius indicate that the optical surface is convex toward the object side or convex toward the image side, and when the optical surface (including the object side surface or the image side surface) is convex toward the object side, the curvature radius of the optical surface is a positive value; when the optical surface (including the object side surface or the image side surface) is convex toward the image side, the optical surface is concave toward the object side, and the radius of curvature of the optical surface is negative.

It should be noted that the shape of the lens and the degree of the concave-convex of the object-side surface and the image-side surface in the drawings are only schematic, and do not limit the embodiments of the present application in any way. In the present application, the material of the lens may be resin (resin), plastic (plastic), or glass (glass). The lens comprises a spherical lens and an aspherical lens. The lens can be a fixed focal length lens or a zoom lens, and can also be a standard lens, a short-focus lens or a long-focus lens.

Referring to fig. 1, a dotted line in fig. 1 is used to indicate an optical axis of the lens.

The monitoring lens 100 of the present embodiment includes, in order from an object side to an image side:

a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104.

It should be understood that the above-mentioned "respective lenses of the monitoring lens" refer to lenses constituting the monitoring lens, and in the embodiment of the present application, are the first lens, the second lens, the third lens, and the fourth lens.

Alternatively, in the embodiments of the present application,

the first lens 101 may have a negative power, the object side S1 of the first lens 101 being convex near the optical axis; the image side surface S2 of the first lens 101 is concave near the optical axis;

the second lens 102 may have positive optical power, an object-side surface S3 of the second lens 102 may be convex near the optical axis, and an image-side surface S4 of the second lens 102 may be convex near the optical axis;

the third lens 103 may have positive optical power, an object side surface S5 of the third lens 103 being convex near the optical axis, and an image side surface S6 of the third lens 103 being convex near the optical axis;

the fourth lens 104 may have a negative power, and the object-side surface S7 of the fourth lens 104 is concave near the optical axis and the image-side surface S8 of the fourth lens 104 is convex near the optical axis.

The monitoring lens 100 satisfies the following relation:

2.3<TTL/f<4.5。

2.3-woven TTL/f <4.5 is specified in the relational expression; preferably 2.7-woven TTL/f <3.8; more preferably 3.1-woven ttl/f <3.2;

for a monitoring lens with a certain total length, within the value range of the TTL/f, the working range of the monitoring lens is effectively improved by lengthening the focal length, so that the monitoring lens still keeps high-quality imaging within a larger range.

In certain implementations of the first aspect, the monitoring lens satisfies: 2.5 knot TTL/(CT 3+ CT 4) <5; preferably 3.4< -TTL/(CT 3+ CT 4) <4.0; more preferably 3.6-woven ttl/(CT 3+ CT 4) <3.9; when the above relational expression is satisfied; in the value range specified by the TTL/(CT 3+ CT 4), the ratio of the third lens and the fourth lens in the total length of the monitoring lens is restrained, so that the aberration of a system is compensated, and the imaging quality of the monitoring lens is improved. When the optimal and more optimal conditions are met, the system aberration can be compensated better, and the imaging quality of the monitoring lens is improved.

In certain implementations of the first aspect, the monitoring lens satisfies: 0.9 yarn of woven fabric f × tan (Semi-Fov)/ImgH <1.1; preferably 0.92</f × tan (Semi-Fov)/ImgH <1.1; more preferably 0.94 woven fabric f × tan (Semi-Fov)/ImgH <1.1; when the maximum image height is fixed, 0.8< -f multiplied by tan (Semi-Fov)/ImgH is restricted to be less than 1.1, and when the focal length is within a certain range, the field angle can be restricted within a reasonable range, so that enough light can enter the monitoring lens, and the imaging quality of the monitoring lens is guaranteed. When the optimal and more optimal conditions are met, the imaging quality of the monitoring lens can be better guaranteed.

In certain implementations of the first aspect, the monitoring lens satisfies: 1.8 sj 12/(T12-T23) <2.7; preferably 2.2-sj 12/(T12-T23) <2.7; more preferably 2.5-f 12/(T12-T23) <2.7; when the relational expression is satisfied, the distances among the first lens, the second lens and the third lens and the combined focal length of the first lens and the second lens are controlled to be reasonably configured, so that the system chromatic aberration of the monitoring lens can be effectively corrected, the distortion and the coma aberration are improved, the resolution of the monitoring lens is improved, and the imaging quality of the monitoring lens is further improved. When the optimal and more optimal conditions are met, the resolution of the monitoring lens can be better improved, and the imaging quality of the monitoring lens can be better improved.

In certain implementations of the first aspect, the monitoring lens satisfies: 0.6-woven fabric (sBFL/f) is less than 0.9; preferably 0.6-woven fabric BFL/f <0.77; more preferably 0.63 woven fabric BFL/f <0.69; when the relation is satisfied, the back focal length is controlled within a reasonable range when the focal length is fixed, so that the working distance of the monitoring lens can be increased, and the monitoring lens still keeps high-quality imaging image quality within a larger shooting distance. When the preferable and more preferable conditions are satisfied, the high-quality imaging image quality can be better maintained in a larger shooting distance.

In certain implementations of the first aspect, the monitoring lens satisfies: 2.2< (R11 + R12)/(R11-R12) <3.2; preferably 2.9< (R11 + R12)/(R11-R12) <3.2; when the relation is satisfied, the curvature radius of the object side surface and the image side surface of the first lens is reasonably controlled, the spherical aberration of the monitoring lens is favorably corrected, and the imaging quality of the monitoring lens is further improved. When the optimal and more optimal conditions are met, the spherical aberration of the monitoring lens can be better corrected, and the imaging quality of the monitoring lens is further improved.

In certain implementations of the first aspect, the monitoring lens satisfies: 0.8< -ImgH/EPD <1.5; preferably 0.85-straw imgh/EPD <1.2; more preferably 0.96 woven-cloth imgh/EPD <1.14; when satisfying above-mentioned relational expression, be favorable to promoting monitor lens's relative aperture, and then increase monitor lens's light flux, be favorable to promoting monitor lens's illuminance to further improve monitor lens's imaging quality. When the optimal and more optimal conditions are met, the illumination of the monitoring lens can be better improved, and the imaging quality of the monitoring lens is further improved.

In certain implementations of the first aspect, the monitoring lens satisfies: 0.2-woven SAG11/DT11<0.8; preferably 0.38-woven SAG11/DT11<0.8; more preferably 0.38-woven SAG11/DT11<0.43; when the relation is satisfied, the aperture of the object side surface of the first lens can be controlled within a reasonable range, more light rays can enter the monitoring lens, enough illumination of the imaging surface of the monitoring lens is guaranteed, stray light entering a wide light beam of the object side surface of the first lens can be filtered, stray light and ghost images of the monitoring lens are reduced, and therefore the imaging quality of the monitoring lens is improved. And when DT11 is determined, 2-Ap SAG11/DT11<8 is met, the distortion of the monitoring lens can be optimized, and the imaging quality of the monitoring lens is further improved. When the optimization and the more optimization conditions are met, the distortion of the monitoring lens can be better optimized, and the imaging quality of the monitoring lens is further improved.

In certain implementations of the first aspect, the monitoring lens satisfies: l Dist. | <13.5%; when the relational expression is satisfied, the monitoring lens is favorable for presenting lower distortion, and the imaging requirement of high quality is realized.

In certain implementations of the first aspect, the material of the first lens is the same as the material of the third lens, so that material waste, material saving, and manufacturing cost reduction can be achieved in the process of manufacturing the first lens and the second lens.

In a second aspect, a monitoring lens module is provided, which includes the monitoring lens in any one of the possible implementation manners of the first aspect, and may further include an image sensor, an analog-to-digital converter, an image processor, a memory, and the like, so as to implement a camera function of the monitoring lens.

Some specific, but non-limiting examples of embodiments of the present application will be described in more detail below in conjunction with fig. 1-30.

In the embodiment of the present application, the material of each lens of the monitoring lens 100 is not particularly limited.

Example one

The monitoring lens 100 of an embodiment of the present application includes, in order from an object side to an image side: a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104, as shown in fig. 1.

For convenience of description, in the following embodiments, STO denotes a surface of a diaphragm, S1 denotes an object-side surface of the first lens 101, S2 denotes an image-side surface of the first lens 101, S3 denotes an object-side surface of the second lens 102, S4 denotes an image-side surface of the second lens 102, S5 denotes an object-side surface of the third lens 103, S6 denotes an image-side surface of the third lens 103, S7 denotes an object-side surface of the fourth lens 104, S8 denotes an image-side surface of the fourth lens 104, S9 denotes an object-side surface of the infrared filter, S10 denotes an image-side surface of the infrared filter, and S11 denotes an imaging surface. The first lens 101 has negative power, and an object side surface S1 of the first lens 101 is convex near the optical axis; the image side surface S2 of the first lens 101 is concave near the optical axis; the second lens 102 has positive focal power, an object side surface S3 of the second lens 102 is convex near the optical axis, and an image side surface S4 of the second lens 102 is convex near the optical axis; the third lens 103 has positive optical power, an object side surface S5 of the third lens 103 is convex near the optical axis, and an image side surface S6 of the third lens 103 is convex near the optical axis; the fourth lens 104 has negative power, and an object-side surface S7 of the fourth lens 104 is concave near the optical axis and an image-side surface S8 of the fourth lens 104 is convex near the optical axis.

The total optical length of the monitoring lens 100 is denoted by TTL, the maximum image height of the monitoring lens 100 is denoted by ImgH, and the effective focal length of the monitoring lens 100 is denoted by EFL. The i-th order aspheric coefficients are represented by α i, i =4, 6, 8, 10, 12, 14, 16, and the cone coefficients are represented by K.

In light of the above relations, table 1 shows the effective focal length EFL, the maximum field angle Fov, the total optical length TTL, the F value f.no, the surface type, the curvature radius, the thickness, the refractive index of the material, and the conic coefficient of the monitoring lens 100 in the first embodiment, where the units of the curvature radius and the thickness are millimeters (mm), as shown in table 1:

TABLE 1

Table 2 shows aspheric coefficients of the monitoring lens 100 according to the first embodiment of the present application, as shown in table 2:

TABLE 2

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

7.242E-04

-9.146E-05

-9.597E-07

9.595E-07

-9.646E-08

-1.779E-09

2.518E-10

S2

-3.018E-03

5.845E-04

-2.696E-04

-5.766E-06

7.026E-06

-3.236E-06

2.954E-07

S3

0.000E+00

S4

0.000E+00

S5

-4.430E-05

-4.703E-05

5.119E-05

-1.651E-05

2.907E-06

-1.685E-07

-1.884E-08

S6

1.102E-02

-1.339E-03

-2.459E-06

1.664E-05

-1.484E-05

3.355E-07

3.483E-07

S7

1.195E-02

-2.376E-03

-9.877E-05

4.858E-05

-9.290E-06

-3.208E-06

7.772E-07

S8

5.064E-03

-4.005E-04

-1.150E-04

3.474E-05

-2.322E-06

-7.757E-07

1.142E-07

Wherein the non-curved surface of each lens of the image pickup optical lens 100 satisfies:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/r (i.e., paraxial curvature c is the inverse of radius of curvature r in table 1 above); k is the conic constant (given in table 1 above); ai is a correction coefficient of the i-n th order of the aspherical surface, and the coefficients of the high-order terms A4, A6, A8, a10, a12, a14, and a16 of the respective lens surfaces S1 to S8 are shown in table 2.

It should be understood that the aspheric surfaces of the lenses in the monitoring lens 100 may use the aspheric surface shown in the above aspheric surface formula, and may also use other aspheric surface formulas, which are not limited in this application.

Given the design data of the monitoring lens 100 according to the first embodiment of the present application, the effective focal length EFL is 6.223mm, the maximum field angle Fov is 55.942 degrees, the total optical length TTL is 19.416mm, and the F-number of the aperture F is 2.134.

In one embodiment provided herein, TTL/f =3.120.

In one embodiment provided herein, TTL/(CT 3+ CT 4) =3.979.

In one embodiment provided herein, f tan (Semi-Fov)/ImgH =1.156.

In one embodiment provided herein, f 12/(T12-T23) =2.293.

In one embodiment provided herein, BFL/f =0.770.

In one embodiment provided herein, (R11 + R12)/(R11-R12) =2.973.

In one embodiment provided herein, imgH/EPD =0.965.

In one embodiment provided herein, SAG11/DT11=0.433.

In one embodiment provided herein, | Dist | =13.500.

Fig. 2 to 5 illustrate the optical performance of the monitoring lens 100 designed in such a manner as to embody one such lens combination.

In the first embodiment, the monitoring lens meets the requirements of large working range and high imaging quality.

Example two

The monitoring lens 100 of an embodiment of the present application includes, in order from an object side to an image side: a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104, as shown in fig. 6.

For convenience of description, in the following embodiments, STO denotes a surface of a diaphragm, S1 denotes an object-side surface of the first lens 101, S2 denotes an image-side surface of the first lens 101, S3 denotes an object-side surface of the second lens 102, S4 denotes an image-side surface of the second lens 102, S5 denotes an object-side surface of the third lens 103, S6 denotes an image-side surface of the third lens 103, S7 denotes an object-side surface of the fourth lens 104, S8 denotes an image-side surface of the fourth lens 104, S9 denotes an object-side surface of the infrared filter, S10 denotes an image-side surface of the infrared filter, and S11 denotes an imaging surface. The first lens 101 has negative power, and the object side surface S1 of the first lens 101 is convex near the optical axis; the image side surface S2 of the first lens 101 is concave near the optical axis; the second lens 102 has positive focal power, an object-side surface S3 of the second lens 102 is convex near the optical axis, and an image-side surface S4 of the second lens 102 is convex near the optical axis; the third lens 103 has positive optical power, an object side surface S5 of the third lens 103 is convex near the optical axis, and an image side surface S6 of the third lens 103 is convex near the optical axis; the fourth lens 104 has negative power, and an object-side surface S7 of the fourth lens 104 is concave near the optical axis and an image-side surface S8 of the fourth lens 104 is convex near the optical axis.

The total optical length of the monitor lens 100 is expressed by TTL, the maximum image height of the monitor lens 100 is expressed by ImgH, and the effective focal length of the monitor lens 100 is expressed by EFL. The ith order aspheric coefficients are denoted by α i, i =4, 6, 8, 10, 12, 14, 16, and the cone coefficients are denoted by K.

In light of the above relations, table 3 shows the effective focal length EFL, the maximum field angle Fov, the total optical length TTL, the F value f.no, the surface type, the curvature radius, the thickness, the refractive index of the material, and the conic coefficient of the monitoring lens 100 in the second embodiment, where the curvature radius and the thickness are both in millimeters (mm), as shown in table 3:

TABLE 3

Table 4 shows aspheric coefficients of the monitoring lens 100 according to the second embodiment of the present application, as shown in table 4:

TABLE 4

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

-1.086E-03

2.850E-06

-3.054E-06

4.153E-07

-4.368E-08

2.687E-09

-6.142E-11

S2

-1.278E-02

1.270E-03

-3.632E-04

2.710E-05

3.816E-07

-7.702E-08

-7.041E-09

S3

0.000E+00

S4

0.000E+00

S5

-5.221E-04

-3.680E-04

7.521E-05

-1.711E-05

3.188E-06

-4.089E-07

1.825E-08

S6

1.346E-02

-1.174E-03

-1.721E-04

1.786E-05

-6.813E-06

1.192E-06

-2.322E-09

S7

1.332E-02

-1.948E-03

1.922E-05

1.868E-05

-8.643E-06

-6.297E-07

2.953E-07

S8

8.643E-03

5.483E-04

4.531E-06

-1.884E-07

-8.184E-07

-1.299E-07

2.389E-08

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/r (i.e., paraxial curvature c is the inverse of radius of curvature r in table 3 above); k is the conic constant (given in table 3 above); ai is a correction coefficient of the i-n th order of the aspherical surface, and the coefficients of the high-order terms A4, A6, A8, a10, a12, a14, and a16 of the respective lens surfaces S1 to S8 are shown in table 4.

Given the design data of the monitoring lens 100 according to the second embodiment of the present application, the effective focal length EFL is 6.433mm, the maximum field angle Fov is 54.377 degrees, the total optical length TTL is 24.323mm, and the F-number of the aperture F is 2.143.

In one embodiment provided herein, TTL/f =3.781.

In one embodiment provided herein, TTL/(CT 3+ CT 4) =3.485.

In one embodiment provided herein, f tan (Semi-Fov)/ImgH =0.908.

In one embodiment provided herein, f 12/(T12-T23) =2.708.

In one embodiment provided herein, BFL/f =0.630.

In one embodiment provided herein, (R11 + R12)/(R11-R12) =2.202.

In one embodiment provided herein, imgH/EPD =1.188.

In one embodiment provided herein, SAG11/DT11=0.213.

In one embodiment provided herein, | Dist | =10.091.

Fig. 7 to 10 illustrate the optical performance of the monitoring lens 100 designed in the manner of combining two lenses according to the embodiment.

In the second embodiment, the monitoring lens meets the requirements of large working range and high imaging quality.

EXAMPLE III

The monitoring lens 100 of an embodiment of the present application includes, in order from an object side to an image side: first lens 101, second lens 102, third lens 103, and fourth lens 104, as shown in fig. 11.

In light of the above relations, table 5 shows the effective focal length EFL, the maximum field angle Fov, the total optical length TTL, the F value f.no, the surface type, the curvature radius, the thickness, the refractive index of the material, and the conic coefficient of the monitoring lens 100 in the third embodiment, where the curvature radius and the thickness are both in millimeters (mm), as shown in table 5:

TABLE 5

Table 6 shows aspheric coefficients of the monitoring lens 100 according to the third embodiment of the present application, as shown in table 6:

TABLE 6

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/r (i.e., paraxial curvature c is the inverse of radius of curvature r in table 5 above); k is the conic constant (given in table 5 above); ai is a correction coefficient of the i-n th order of the aspherical surface, and the coefficients of the high-order terms A4, A6, A8, a10, a12, a14, and a16 of the respective lens surfaces S1 to S8 are shown in table 6.

Given the design data of the monitoring lens 100 according to the third embodiment of the present application, the effective focal length EFL is 5.023mm, the maximum field angle Fov is 66.677 degrees, the total optical length TTL is 22.607mm, and the F-number of the aperture F is 2.109.

In one embodiment provided herein, TTL/f =4.500.

In one embodiment provided herein, TTL/(CT 3+ CT 4) =5.000.

In one embodiment provided herein, f tan (Semi-Fov)/ImgH =0.922.

In one embodiment provided herein, f 12/(T12-T23) =1.800.

In one embodiment provided herein, BFL/f =0.917.

In one embodiment provided herein, (R11 + R12)/(R11-R12) =3.201.

In one embodiment provided herein, imgH/EPD =1.499.

In one embodiment provided herein, SAG11/DT11=0.799.

In one embodiment provided herein, | Dist | =8.484.

Fig. 12 to 15 illustrate the optical performance of the monitoring lens 100 designed in such a manner as to combine the three lenses according to the embodiment.

In the third embodiment, the monitoring lens meets the requirements of large working range and high imaging quality.

Example four

The monitoring lens 100 of an embodiment of the present application includes, in order from an object side to an image side: first lens 101, second lens 102, third lens 103, and fourth lens 104, as shown in fig. 16.

For convenience of description, in the following embodiments STO denotes a surface of a diaphragm, S1 denotes an object side surface of the first lens 101, S2 denotes an image side surface of the first lens 101, S3 denotes an object side surface of the second lens 102, S4 denotes an image side surface of the second lens 102, S5 denotes an object side surface of the third lens 103, S6 denotes an image side surface of the third lens 103, S7 denotes an object side surface of the fourth lens 104, S8 denotes an image side surface of the fourth lens 104, S9 denotes an object side surface of the infrared filter, S10 denotes an image side surface of the infrared filter, and S11 denotes an imaging surface. The first lens 101 has negative power, and an object side surface S1 of the first lens 101 is convex near the optical axis; the image side surface S2 of the first lens 101 is concave near the optical axis; the second lens 102 has positive focal power, an object side surface S3 of the second lens 102 is convex near the optical axis, and an image side surface S4 of the second lens 102 is convex near the optical axis; the third lens 103 has positive optical power, an object side surface S5 of the third lens 103 is convex near the optical axis, and an image side surface S6 of the third lens 103 is convex near the optical axis; the fourth lens 104 has negative power, and an object-side surface S7 of the fourth lens 104 is concave near the optical axis and an image-side surface S8 of the fourth lens 104 is convex near the optical axis.

The total optical length of the monitoring lens 100 is denoted by TTL, the maximum image height of the monitoring lens 100 is denoted by ImgH, and the effective focal length of the monitoring lens 100 is denoted by EFL. The ith order aspheric coefficients are denoted by α i, i =4, 6, 8, 10, 12, 14, 16, and the cone coefficients are denoted by K.

In light of the above relations, table 7 shows the effective focal length EFL, the maximum field angle Fov, the total optical length TTL, the F value f.no, the surface type, the curvature radius, the thickness, the refractive index of the material, and the conic coefficient of the monitoring lens 100 in the fourth embodiment, where the curvature radius and the thickness are both in millimeters (mm), as shown in table 7:

TABLE 7

Table 8 shows aspheric coefficients of the monitoring lens 100 according to the fourth embodiment of the present application, as shown in table 8:

TABLE 8

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/r (i.e., paraxial curvature c is the inverse of radius of curvature r in table 7 above); k is the conic constant (given in table 7 above); ai is a correction coefficient of the i-n th order of the aspherical surface, and the coefficients of the high-order terms A4, A6, A8, a10, a12, a14, and a16 of the respective lens surfaces S1 to S8 are shown in table 8.

Given the design data of the monitoring lens 100 according to the fourth embodiment of the present application, the effective focal length EFL is 7.589mm, the maximum field angle Fov is 47.059 degrees, the total optical length TTL is 20.977mm, and the F-number of the aperture F is 2.120.

In one embodiment provided herein, TTL/f =2.764.

In one embodiment provided herein, TTL/(CT 3+ CT 4) =3.618.

In one embodiment provided herein, f tan (Semi-Fov)/ImgH =1.118.

In one embodiment provided herein, f 12/(T12-T23) =2.722.

In one embodiment provided herein, BFL/f =0.690.

In one embodiment provided herein, (R11 + R12)/(R11-R12) =2.981.

In one embodiment provided herein, imgH/EPD =0.818.

In one embodiment provided herein, SAG11/DT11=0.423.

In one embodiment provided herein, | Dist | =10.598.

Fig. 17 to 20 illustrate the optical performance of the monitoring lens 100 designed in the four lens combinations of the embodiment.

In the fourth embodiment, the monitoring lens meets the requirements of large working range and high imaging quality.

EXAMPLE five

The monitoring lens 100 of an embodiment of the present application includes, in order from an object side to an image side: first lens 101, second lens 102, third lens 103, and fourth lens 104, as shown in fig. 21.

For convenience of description, in the following embodiments, STO denotes a surface of a diaphragm, S1 denotes an object-side surface of the first lens 101, S2 denotes an image-side surface of the first lens 101, S3 denotes an object-side surface of the second lens 102, S4 denotes an image-side surface of the second lens 102, S5 denotes an object-side surface of the third lens 103, S6 denotes an image-side surface of the third lens 103, S7 denotes an object-side surface of the fourth lens 104, S8 denotes an image-side surface of the fourth lens 104, S9 denotes an object-side surface of the infrared filter, S10 denotes an image-side surface of the infrared filter, and S11 denotes an imaging surface. The first lens 101 has negative power, and the object side surface S1 of the first lens 101 is convex near the optical axis; the image side surface S2 of the first lens 101 is concave near the optical axis; the second lens 102 has positive focal power, the object side surface S3 of the second lens 102 is convex near the optical axis, and the image side surface S4 of the second lens 102 is concave near the optical axis; the third lens 103 has positive optical power, an object-side surface S5 of the third lens 103 is convex near the optical axis, and an image-side surface S6 of the third lens 103 is convex near the optical axis; the fourth lens 104 has negative power, and an object-side surface S7 of the fourth lens 104 is concave near the optical axis and an image-side surface S8 of the fourth lens 104 is convex near the optical axis.

In light of the above relation, table 9 shows the effective focal length EFL, the maximum field angle Fov, the total optical length TTL, the F value f.no, the surface type, the curvature radius, the thickness, the refractive index of the material, and the conic coefficient of the monitoring lens 100 in the fifth embodiment, where the units of the curvature radius and the thickness are millimeters (mm), as shown in table 9:

TABLE 9

Table 10 shows aspheric coefficients of the monitoring lens 100 according to the fifth embodiment of the present application, as shown in table 10:

watch 10

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

-9.687E-05

-1.448E-04

6.992E-06

-2.818E-07

-1.212E-07

1.525E-08

-4.995E-10

S2

-8.226E-03

-9.448E-04

-1.701E-05

6.787E-06

-8.570E-06

2.237E-06

-1.775E-07

S3

0.000E+00

S4

0.000E+00

S5

-5.668E-04

3.100E-05

3.873E-05

-2.563E-05

4.376E-06

2.197E-07

-1.165E-07

S6

1.558E-02

-1.451E-03

3.371E-07

1.007E-04

-1.653E-05

-9.798E-06

-6.769E-06

S7

1.435E-02

-1.388E-03

-4.472E-05

-2.383E-05

1.353E-05

-4.974E-07

-8.583E-06

S8

8.384E-03

4.979E-03

-2.275E-03

5.086E-08

2.289E-04

-8.730E-06

-9.681E-06

wherein x is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/r (i.e., paraxial curvature c is the inverse of radius of curvature r in table 9 above); k is the conic constant (given in table 9 above); ai is a correction coefficient of the i-n th order of the aspherical surface, and the coefficients of the high-order terms A4, A6, A8, a10, a12, a14, and a16 of the respective lens surfaces S1 to S8 are shown in table 10.

Given the design data of the monitoring lens 100 according to the fifth embodiment of the present application, the effective focal length EFL is 7.425mm, the maximum field angle Fov is 47.984 degrees, the total optical length TTL is 17.158mm, and the F-number of the aperture F is 2.091.

In one embodiment provided herein, TTL/f =2.311.

In one embodiment provided herein, TTL/(CT 3+ CT 4) =4.048.

In one embodiment provided herein, f tan (Semi-Fov)/ImgH =1.098.

In one embodiment provided herein, f 12/(T12-T23) =2.744.

In one embodiment provided herein, BFL/f =0.630.

In one example provided herein, (R11 + R12)/(R11-R12) =3.220.

In one embodiment provided herein, imgH/EPD =0.851.

In one embodiment provided herein, SAG11/DT11=0.389.

In one embodiment provided herein, | Dist | =8.920.

Fig. 22 to 25 illustrate the optical performance of the monitoring lens 100 designed in such a lens combination as described in example five.

In the fifth embodiment, the monitoring lens meets the requirements of large working range and high imaging quality.

EXAMPLE six

The monitoring lens 100 of an embodiment of the present application includes, in order from an object side to an image side: first lens 101, second lens 102, third lens 103, and fourth lens 104, as shown in fig. 26.

For convenience of description, in the following embodiments, STO denotes a surface of a diaphragm, S1 denotes an object-side surface of the first lens 101, S2 denotes an image-side surface of the first lens 101, S3 denotes an object-side surface of the second lens 102, S4 denotes an image-side surface of the second lens 102, S5 denotes an object-side surface of the third lens 103, S6 denotes an image-side surface of the third lens 103, S7 denotes an object-side surface of the fourth lens 104, S8 denotes an image-side surface of the fourth lens 104, S9 denotes an object-side surface of the infrared filter, S10 denotes an image-side surface of the infrared filter, and S11 denotes an imaging surface. The first lens 101 has negative power, and the object side surface S1 of the first lens 101 is convex near the optical axis; the image side surface S2 of the first lens 101 is concave near the optical axis; the second lens 102 has positive focal power, an object side surface S3 of the second lens 102 is convex near the optical axis, and an image side surface S4 of the second lens 102 is convex near the optical axis; the third lens 103 has positive optical power, an object side surface S5 of the third lens 103 is convex near the optical axis, and an image side surface S6 of the third lens 103 is convex near the optical axis; the fourth lens 104 has negative power, and an object-side surface S7 of the fourth lens 104 is concave near the optical axis and an image-side surface S8 of the fourth lens 104 is convex near the optical axis.

In light of the above relations, table 11 shows the effective focal length EFL, the maximum field angle Fov, the total optical length TTL, the F value f.no, the surface type, the curvature radius, the thickness, the refractive index of the material, and the conic coefficient of the monitoring lens 100 in the sixth embodiment, where the curvature radius and the thickness are both in millimeters (mm), as shown in table 11:

TABLE 11

Table 12 shows aspheric coefficients of the monitoring lens 100 according to the sixth embodiment of the present application, as shown in table 12:

TABLE 12

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

3.887E-04

-3.269E-04

1.651E-05

-6.356E-09

-1.870E-07

1.613E-08

-2.566E-10

S2

-5.195E-03

-9.180E-06

-3.523E-04

-5.790E-06

3.745E-06

6.036E-07

-1.575E-07

S3

0.000E+00

S4

0.000E+00

S5

-4.389E-06

-1.044E-04

5.534E-05

-1.835E-05

3.587E-06

-3.657E-07

1.469E-08

S6

1.259E-02

-1.067E-03

-8.037E-06

5.094E-05

-7.422E-06

-4.747E-08

-6.324E-10

S7

1.182E-02

-1.786E-03

1.246E-04

3.716E-05

-7.225E-06

-3.704E-07

5.806E-08

S8

6.238E-03

-2.902E-04

1.250E-04

-1.364E-05

-2.026E-06

6.634E-07

-5.008E-08

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/r (i.e., paraxial curvature c is the inverse of radius of curvature r in table 11 above); k is the conic constant (given in table 11 above); ai is a correction coefficient of the i-n th order of the aspherical surface, and the coefficients of the high-order terms A4, A6, A8, a10, a12, a14, and a16 of the respective lens surfaces S1 to S8 are shown in table 12.

It should be understood that the aspheric surfaces of the lenses in the monitoring lens 100 may use the aspheric surface shown in the above aspheric surface formula, and may also use other aspheric surface formulas, which is not limited in this application.

Given the design data of the monitoring lens 100 according to the sixth embodiment of the present application, the effective focal length EFL is 6.426mm, the maximum field angle Fov is 54.431 degrees, the total optical length TTL is 20.619mm, and the F-number of the aperture F is 2.133.

In one embodiment provided herein, TTL/f =3.209.

In one embodiment provided herein, TTL/(CT 3+ CT 4) =2.503.

In one embodiment provided herein, f tan (Semi-Fov)/ImgH =0.944.

In one embodiment provided herein, f 12/(T12-T23) =2.582.

In one embodiment provided herein, BFL/f =0.603.

In one embodiment provided herein, (R11 + R12)/(R11-R12) =3.207.

In one embodiment provided herein, imgH/EPD =1.144.

In one embodiment provided herein, SAG11/DT11=0.382.

In one embodiment provided herein, | Dist | =5.945.

Fig. 27 to 30 illustrate the optical performance of the monitoring lens 100 designed in such a lens combination manner as six embodiments.

In the sixth embodiment, the monitoring lens meets the requirements of large working range and high imaging quality.

In addition, examples one to six correspond to TTL/f ratio, TTL/(CT 3+ CT 4) ratio, f tan (Semi-Fov)/ImgH ratio, f 12/(T12-T23) ratio, BFL/f ratio, (R11 + R12)/(R11-R12) ratio, imgH/EPD ratio, SAG11/DT11 ratio, and | Dist | value, as shown in table 13:

watch 13

Conditional formula (II)	Example one	Example two	EXAMPLE III	Example four	EXAMPLE five	EXAMPLE six
							TTL/f	3.120	3.781	4.500	2.764	2.311	3.209
TTL/(CT3+CT4)	3.979	3.485	5.000	3.618	4.048	2.503
							f*tan(Semi-Fov)/ImgH	1.156	0.908	0.922	1.118	1.098	0.944
f12/(T12-T23)	2.293	2.708	1.800	2.722	2.744	2.582
							BFL/f	0.770	0.630	0.917	0.690	0.630	0.603
(R11+R12)/(R11-R12)	2.973	2.202	3.201	2.981	3.220	3.207
							ImgH/EPD	0.965	1.188	1.499	0.818	0.851	1.144
SAG11/DT11	0.433	0.213	0.799	0.423	0.389	0.382
							\|Dist.\|	13.500	10.091	8.484	10.598	8.920	5.945

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. The invention is not to be limited to the specific embodiments disclosed herein, but to other embodiments falling within the scope of the claims of the present application.

Claims

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

a second lens having positive refractive power, an image-side surface of which is convex near the optical axis;

a fourth lens having a negative optical power, an object side surface of which is concave near the optical axis;

the monitoring lens meets the following conditional expression:

2.3<TTL/f<4.5；

2.5<TTL/(CT3+CT4)<5；

2. The monitoring lens according to claim 1, wherein the monitoring lens satisfies the following conditional expression:

0.9<f×tan(Semi-Fov)/ImgH<1.1；

3. A monitoring lens according to claim 1 or 2, characterized in that the monitoring lens satisfies the following conditional expression:

1.8<f12/(T12-T23)<2.7；

4. A monitoring lens according to claim 3, wherein the monitoring lens satisfies the following conditional expression:

0.6<BFL/f<0.9；

5. The monitoring lens according to claim 4, wherein the monitoring lens satisfies the following conditional expression:

2.2<(R11+R12)/(R11-R12)<3.2；

wherein R11 is a radius of curvature of the object-side surface of the first lens; and R12 is the curvature radius of the image side surface of the first lens.

6. The monitoring lens according to claim 4 or 5, wherein the monitoring lens satisfies the following conditional expression:

0.8<ImgH/EPD<1.5；

7. The monitoring lens according to claim 6, wherein the monitoring lens satisfies the following conditional expression:

0.2<SAG11/DT11<0.8

SAG11 is the distance on the optical axis from the intersection point of the object-side surface of the first lens and the optical axis to the effective radius vertex of the object-side surface of the first lens, and DT11 is the maximum effective radius of the object-side surface of the first lens.

8. The monitoring lens according to any one of claims 1 to 7, wherein the monitoring lens satisfies the following conditional expression:

|Dist.|<13.5％；

and Dist is the maximum optical distortion of the monitoring lens.

9. The monitoring lens according to claim 8, characterized in that:

the material of the first lens is the same as that of the third lens.

10. A camera module, characterized by comprising the monitoring lens according to any one of claims 1 to 9.