CN114114636A

CN114114636A - Optical lens group

Info

Publication number: CN114114636A
Application number: CN202111518805.1A
Authority: CN
Inventors: 姚志飞; 张晓彬; 闻人建科; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-03-01
Also published as: CN117492176A

Abstract

The invention provides an optical lens group. The optical lens group sequentially comprises from the light incidence side to the light emergence side along the optical axis: the surface of the first lens, which is close to the incident side, is a convex surface, and the surface of the first lens, which is close to the emergent side, is a convex surface; a diaphragm; a second lens; a third lens; a fourth lens; the effective focal length f of the optical lens group and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.9< f/TTL < 1; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8. The invention solves the problem that the optical lens group in the prior art has long focus, large aperture and high image quality which are difficult to be considered simultaneously.

Description

Optical lens group

Technical Field

The invention relates to the technical field of optical imaging equipment, in particular to an optical lens group.

Background

With the continuous improvement of the requirements of people on the photographing quality and various performances of the mobile phone, the optical lens group with the characteristics of long focus, wide angle, large image plane, large aperture and the like is continuously updated, and the pictures photographed by the mobile phone are clearer and clearer, so that the mobile phone is popular with consumers.

At present, an optical lens group is provided in the prior art, which has a long-focus characteristic, but the relative aperture size is difficult to satisfy the user requirement, so that the imaging effect of the optical lens group when shooting objects with a long distance is poor, the definition is poor, and it is difficult to ensure that enough imaging light enters the optical system in a dark environment, so that the final imaging quality is easily affected, and the imaging effect of the shot picture is poor in a dark environment.

That is, the optical lens assembly in the prior art has the problem that the long focus, the large aperture and the high image quality are difficult to be simultaneously considered.

Disclosure of Invention

The invention mainly aims to provide an optical lens group to solve the problem that the optical lens group in the prior art has long focus, large aperture and high image quality which are difficult to simultaneously consider.

In order to achieve the above object, according to one aspect of the present invention, there is provided an optical lens group comprising, in order from a light incident side to a light exiting side along an optical axis: the surface of the first lens, which is close to the incident side, is a convex surface, and the surface of the first lens, which is close to the emergent side, is a convex surface; a diaphragm; a second lens; a third lens; a fourth lens; the effective focal length f of the optical lens group and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.9< f/TTL < 1; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8.

Further, an on-axis distance BFL from the surface of the fourth lens closer to the exit side to the imaging surface and an on-axis distance TTL from the surface of the first lens closer to the incident side to the imaging surface satisfy: 0.5< BFL/TTL < 0.7.

Further, a distance SD on the optical axis from the diaphragm to the surface of the fourth mirror closer to the exit side and a distance TD on the optical axis from the surface of the first mirror closer to the incident side to the surface of the fourth mirror closer to the exit side satisfy: 0.5< SD/TD < 0.8.

Further, the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy: 0.3< f1/f < 0.6.

Further, the effective focal length f1 of the first lens and the curvature radius R1 of the surface of the first lens close to the incident side satisfy: 0.5< R1/f1< 1.

Further, the air space T23 on the optical axis of the second lens and the third lens and the sum Σ AT of the air spaces on the optical axis between adjacent two of the first lens to the fourth lens satisfy: 0.5< T23/∑ AT <1.

Further, the central thickness CT2 of the second lens on the optical axis and the central thickness CT3 of the third lens on the optical axis satisfy: 0.5< CT2/CT3< 1.1.

Further, a center thickness CT1 of the first lens on the optical axis and a sum Σ CT of center thicknesses of the first lens to the fourth lens on the optical axis satisfy: 0.35< CT1/∑ CT < 0.5.

Further, the abbe number V1 of the first lens and the abbe number V2 of the second lens satisfy: 0.4< V2/V1< 0.5.

Further, the refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy the following condition: 0.8< N3/N2< 1.1.

Further, the maximum effective radius DT11 of the surface of the first lens close to the incident side and the maximum effective radius DT42 of the surface of the fourth lens close to the exit side satisfy: 0.6< DT42/DT11 <1.

Further, the sum Σ ET of the edge thicknesses on the optical axis of the first to fourth lenses and the sum Σ CT of the center thicknesses on the optical axis of the first to fourth lenses satisfy: 0.8< ∑ ET/Σ CT < 0.9.

Further, the edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis satisfy that: ET2/ET1 is more than or equal to 0.8 and less than or equal to 1.2.

Further, the edge thickness ET2 of the second lens on the optical axis and the center thickness CT2 of the second lens on the optical axis satisfy: 1< ET2/CT2< 2.

Further, the maximum center thickness CT on the optical axis among the first lens to the fourth lens_MAXAnd the minimum central thickness CT on the optical axis among the first lens to the fourth lens_MINSatisfies the following conditions: 2<CT_MAX/CT_MIN<5。

According to another aspect of the present invention, there is provided an optical lens assembly, comprising, in order from a light incident side to a light exiting side along an optical axis: the surface of the first lens, which is close to the incident side, is a convex surface, and the surface of the first lens, which is close to the emergent side, is a convex surface; a diaphragm; a second lens; a third lens; a fourth lens; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.5< BFL/TTL < 0.7.

Further, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens element close to the incident side to the imaging surface satisfy: 0.9< f/TTL < 1; the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy the following relationship: 0.3< f1/f < 0.6.

By applying the technical scheme of the invention, the optical lens group sequentially comprises a first lens, a diaphragm, a second lens, a third lens and a fourth lens from the light incidence side to the light emergence side along the optical axis; the surface of the first lens close to the incident side is a convex surface, and the surface close to the emergent side is a convex surface; the effective focal length f of the optical lens group and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.9< f/TTL < 1; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8.

Through the face type of reasonable control lens, can effectively eliminate the aberration of optics lens group, improve the quality that optics lens group caught light. Through the effective focal length f of the rational restraint optics lens group and the ratio between the axial distance TTL from the surface close to the incident side of the first lens to the imaging surface, the ratio between the axial distance BFL from the surface close to the emergent side of the fourth lens to the imaging surface and the effective focal length f of the optics lens group, the shooting requirement of the super-long distance of the user can be met, and the tail end stray light is improved and the imaging quality is ensured by matching the requirement of the module end.

In addition, the optical lens group of the application can be added with a prism to be used as a periscopic telephoto lens. Compare the telephoto lens of the same kind on the market, the light ring is great, consequently not only can keep clear imaging ability to the object in a distance at the actual shooting in-process to can guarantee that there is sufficient formation of image light to get into optical system in taking at night, reduce the noise point of formation of image picture, make under the dark scenery environment, the photo of shooing can have fine formation of image effect.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of an optical lens assembly according to a first embodiment of the present invention;

fig. 2 to 5 respectively show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve and a distortion curve of the optical lens set of fig. 1;

FIG. 6 is a schematic view of an optical lens assembly according to a second example of the present invention;

fig. 7 to 10 show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve and a distortion curve of the optical lens set of fig. 6, respectively;

FIG. 11 is a schematic structural diagram of an optical lens assembly according to a third example of the present invention;

fig. 12 to 15 show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve and a distortion curve of the optical lens group of fig. 11, respectively;

FIG. 16 is a schematic view of an optical lens assembly according to example four of the present invention;

fig. 17 to 20 show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve and a distortion curve of the optical lens group of fig. 16, respectively;

FIG. 21 is a schematic view of an optical lens assembly according to example five of the present invention;

fig. 22 to 25 show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve and a distortion curve of the optical lens group of fig. 21, respectively;

FIG. 26 is a schematic view of an optical lens set according to example six of the present invention;

fig. 27 to 30 show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve and a distortion curve of the optical lens group of fig. 26, respectively;

FIG. 31 is a schematic diagram of an optical lens assembly according to a seventh example of the present invention;

fig. 32 to 35 show an axial chromatic aberration curve, a magnification chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical lens group in fig. 31, respectively.

Wherein the figures include the following reference numerals:

e1, a first lens; s1, the surface of the first lens close to the incident side; s2, the surface of the first lens close to the emergent side; STO, stop; e2, a second lens; s3, the surface of the second lens close to the incident side; s4, the surface of the second lens close to the emergent side; e3, third lens; s5, the surface of the third lens close to the incident side; s6, the surface of the third lens close to the emergent side; e4, fourth lens; s7, the surface of the fourth lens close to the incident side; s8, the surface of the fourth lens close to the emergent side; e5, optical filters; s9, the surface of the filter close to the incident side; s10, the surface of the filter close to the emergent side; and S11, imaging surface.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It is noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In the present invention, unless specified to the contrary, use of the terms of orientation such as "upper, lower, top, bottom" or the like, generally refer to the orientation as shown in the drawings, or to the component itself in a vertical, perpendicular, or gravitational orientation; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present application.

In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for the convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens close to the light incidence side becomes the surface of the lens close to the incidence side, and the surface of each lens close to the light emergence side is called the surface of the lens close to the emergence side. The determination of the surface shape in the paraxial region can be made by determining whether or not the surface shape is concave or convex using an R value (R denotes a radius of curvature of the paraxial region, and usually denotes an R value in a lens database (lens data) in optical software) according to a determination method by a person ordinarily skilled in the art. On the surface close to the incident side, when the R value is positive, the surface is judged to be convex, and when the R value is negative, the surface is judged to be concave; the surface closer to the emission side is determined to be concave when the R value is positive, and is determined to be convex when the R value is negative.

The invention provides an optical lens group, aiming at solving the problem that the optical lens group in the prior art has long focus, large aperture and high image quality which are difficult to simultaneously consider.

Example one

As shown in fig. 1 to 35, the optical lens assembly includes a first lens, a diaphragm, a second lens, a third lens and a fourth lens in sequence from the light incident side to the light emergent side along the optical axis; the surface of the first lens close to the incident side is a convex surface, and the surface close to the emergent side is a convex surface; the effective focal length f of the optical lens group and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.9< f/TTL < 1; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8.

In this embodiment, an on-axis distance BFL from a surface of the fourth lens closer to the exit side to the imaging plane and an on-axis distance TTL from a surface of the first lens closer to the incident side to the imaging plane satisfy: 0.5< BFL/TTL < 0.7. Through the ratio of the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface, the requirement of the back focal of the optical lens group is met on one hand, and on the other hand, unnecessary stray light caused by the tail end of the lens barrel is effectively reduced.

In this embodiment, a distance SD on the optical axis from the diaphragm to the surface of the fourth mirror closer to the exit side and a distance TD on the optical axis from the surface of the first mirror closer to the incident side to the surface of the fourth mirror closer to the exit side satisfy: 0.5< SD/TD < 0.8. Through the ratio of the distance SD between the distance SD on the optical axis from the surface close to the emergent side of the diaphragm to the fourth lens and the distance TD between the surface close to the incident side of the first lens and the surface close to the emergent side of the fourth lens and the distance TD on the optical axis, the air gap between the three optical lenses can be restrained, the using number of thick space rings in the optical lens group is reduced, the contact area of light and the space rings can also be reduced, stray light caused by the thick space rings is effectively reduced, and the imaging quality is improved.

In the present embodiment, the effective focal length f of the optical lens group and the effective focal length f1 of the first lens element satisfy: 0.3< f1/f < 0.6. The conditional expression is satisfied, the deflection of light rays in the first lens can be slowed down, the overlarge focal power of the first lens is avoided, the sensitivity of the first lens is reduced, the too tight tolerance requirement is avoided, and the spherical aberration generated by the first lens can be reduced.

In the present embodiment, the effective focal length f1 of the first lens and the radius of curvature R1 of the surface of the first lens on the incident side satisfy: 0.5< R1/f1< 1. The shape of the first lens can be effectively controlled, the manufacturability is improved, and the ghost image is obviously improved.

In the present embodiment, the air space T23 on the optical axis of the second lens and the third lens and the sum Σ AT of the air spaces on the optical axis between adjacent two lenses of the first lens to the fourth lens satisfy: 0.5< T23/∑ AT <1. The size of the space ring in the optical lens group can be effectively reduced, and the contact area between light and the space ring is reduced, so that the stray light influence caused by the space ring is reduced, and the imaging quality is ensured.

In the present embodiment, the central thickness CT2 of the second lens on the optical axis and the central thickness CT3 of the third lens on the optical axis satisfy: 0.5< CT2/CT3< 1.1. The arrangement is characterized in that on one hand, the uniformity of the thickness of the lens is improved, the processing difficulty is reduced, and on the other hand, the ghost image reflected between the second lens and the third lens is improved.

In the present embodiment, the central thickness CT1 of the first lens on the optical axis and the sum Σ CT of the central thicknesses of the first lens to the fourth lens on the optical axis satisfy: 0.35< CT1/∑ CT < 0.5. The condition is satisfied, and the situation that the process difficulty is increased due to the fact that the central thickness of the first lens on the optical axis is too large or too small is avoided. In the present embodiment, the abbe number V1 of the first lens and the abbe number V2 of the second lens satisfy: 0.4< V2/V1< 0.5. Satisfying the conditional expression is beneficial to balancing the dispersion generated by the first lens and the second lens.

In the embodiment, the refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy: 0.8< N3/N2< 1.1. The optical lens group can effectively control the light transmission trend, improve the light collection capability of the optical lens group, improve the illumination and effectively reduce the sensitivity of the lens.

In the present embodiment, the maximum effective radius DT11 of the surface of the first lens closer to the incident side and the maximum effective radius DT42 of the surface of the fourth lens closer to the exit side satisfy: 0.6< DT42/DT11 <1. The condition is satisfied, on the premise of not affecting the performance of the optical lens group, on one hand, the size of the tail end of the lens cone can be reduced, and space is reserved for the motor; on the other hand, the stability of the assembly process is ensured.

In the present embodiment, the sum Σ ET of the edge thicknesses on the optical axis of the first to fourth lenses and the sum Σ CT of the center thicknesses on the optical axis of the first to fourth lenses satisfy: 0.8< ∑ ET/Σ CT < 0.9. The conditional expression is satisfied, on one hand, the uniformity of each lens in the optical lens group is ensured, and the process difficulty is reduced; and on the other hand, stray light and ghost images are effectively improved.

In the present embodiment, the edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis satisfy: ET2/ET1 is more than or equal to 0.8 and less than or equal to 1.2. The conditional expression is satisfied, on one hand, the improvement of stray light and ghost image is facilitated; and on the other hand, feasibility is provided for process processing.

In the present embodiment, the edge thickness ET2 of the second lens on the optical axis and the central thickness CT2 of the second lens on the optical axis satisfy: 1< ET2/CT2< 2. The condition is satisfied, on one hand, the second lens can be ensured not to be too thick or too thin, so that the second lens cannot be processed technically; and on the other hand, improves the ghost image of the second lens. Preferably, 1.2< ET2/CT2< 1.8.

In the present embodiment, the maximum center thickness CT on the optical axis among the first lens to the fourth lens_MAXAnd the minimum central thickness CT on the optical axis among the first lens to the fourth lens_MINSatisfies the following conditions: 2<CT_MAX/CT_MIN<5. The condition is satisfied, and the stability of the optical lens group is ensured. Preferably, 2.1<CT_MAX/CT_MIN<4.2。

Example two

As shown in fig. 1 to 35, the optical lens assembly includes a first lens, a diaphragm, a second lens, a third lens and a fourth lens in sequence from the light incident side to the light emergent side along the optical axis; the surface of the first lens close to the incident side is a convex surface, and the surface of the first lens close to the emergent side is a convex surface; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.5< BFL/TTL < 0.7.

Through the face type of reasonable control lens, can effectively eliminate the aberration of optics lens group, improve the quality that optics lens group caught light. Through the ratio between the axial distance BFL from the surface close to the emergent side of the fourth lens to the imaging surface and the effective focal length f of the optical lens group, the shooting requirement of the super-long distance of a user can be met, and meanwhile, the requirement of the module end is matched, the tail end stray light is improved, and the imaging quality is guaranteed. Through the ratio of the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface, the requirement of the back focal of the optical lens group is met on one hand, and on the other hand, unnecessary stray light caused by the tail end of the lens barrel is effectively reduced.

In this embodiment, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens element close to the incident side to the image plane satisfy: 0.9< f/TTL <1. Through the effective focal length f of the reasonable restraint optics lens group and the ratio between the axial distance TTL of the first lens piece from the surface close to the incident side to the imaging surface, the shooting requirement of the super-long distance of a user can be met, and meanwhile, the requirement of a module end is matched, tail end stray light is improved, and the imaging quality is guaranteed.

In the present embodiment, the central thickness CT1 of the first lens on the optical axis and the sum Σ CT of the central thicknesses of the first lens to the fourth lens on the optical axis satisfy: 0.35< CT1/∑ CT < 0.5. The condition is satisfied, and the situation that the process difficulty is increased due to the fact that the central thickness of the first lens on the optical axis is too large or too small is avoided.

In the present embodiment, the abbe number V1 of the first lens and the abbe number V2 of the second lens satisfy: 0.4< V2/V1< 0.5. Satisfying the conditional expression is beneficial to balancing the dispersion generated by the first lens and the second lens.

In the present embodiment, the maximum center thickness CT on the optical axis among the first lens to the fourth lens_MAXAnd the minimum central thickness CT on the optical axis among the first lens to the fourth lens_MINIs full ofFoot: 2<CT_MAX/CT_MIN<5. The condition is satisfied, and the stability of the optical lens group is ensured. Preferably, 2.1<CT_MAX/CT_MIN<4.2。

Optionally, the optical lens group may further include a filter for correcting color deviation or a protective glass for protecting a photosensitive element on the image plane.

The optical lens assembly in the present application may employ a plurality of lenses, such as the four lenses described above. By reasonably distributing the focal power, the surface shape, the center thickness of each lens, the on-axis distance between each lens and the like, the sensitivity of the lens can be reduced, the machinability of the lens can be improved, and the optical lens group is more favorable for production and processing and can be suitable for portable electronic equipment such as smart phones. The left side is the light incident side and the right side is the light emergent side.

In the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The aspheric lens has the characteristics that: the curvature varies continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the lens center to the lens periphery, an aspherical lens has a better curvature radius characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality.

However, it is understood by those skilled in the art that the number of lenses constituting the optical lens group may be varied to obtain the various results and advantages described in the present description without departing from the technical solutions claimed in the present application. For example, although four lenses are exemplified in the embodiments, the optical lens group is not limited to include four lenses. The optical lens set can also include other numbers of lenses, if necessary.

Examples of specific surface types and parameters of the optical lens set applicable to the above embodiments are further described below with reference to the drawings.

It should be noted that any one of the following examples one to seven is applicable to all embodiments of the present application.

Example one

Fig. 1 to 5 show an optical lens assembly according to a first example of the present application. Fig. 1 is a schematic diagram illustrating a structure of an optical lens set according to an example one.

As shown in fig. 1, the optical lens assembly sequentially includes, from the light incident side to the light emergent side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

The first lens E1 has positive power, and the surface S1 of the first lens near the incident side is a convex surface, and the surface S2 of the first lens near the exit side is a convex surface. The second lens E2 has negative power, the surface S3 of the second lens near the incident side is convex, and the surface S4 of the second lens near the exit side is concave. The third lens E3 has positive optical power, and the surface S5 of the third lens near the incident side is a concave surface, and the surface S6 of the third lens near the exit side is a convex surface. The fourth lens E4 has positive optical power, and the surface S7 of the fourth lens near the incident side is a convex surface, and the surface S8 of the fourth lens near the exit side is a concave surface. The filter E5 has a face S9 on the incident side of the filter and a face S10 on the emission side of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging surface S11.

In this example, the effective focal length f of the optical lens group is 17.41mm, the total system length TTL of the optical lens group is 11.64mm, and the optical back focus BFL is 18.64 mm.

Table 1 shows a table of basic structural parameters of the optical lens assembly of example one, wherein the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are all millimeters (mm).

TABLE 1

In the first example, the surface near the incident side and the surface near the exit side of any one of the first lens E1 to the fourth lens E4 are aspheric surfaces, and the surface type of each aspheric surface lens can be defined by, but is not limited to, the following aspheric surface formula:

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 being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 below gives the high-order coefficient coefficients A4, A6, A8, A10, A12, A14, A16 that can be used for each of the aspherical mirrors S1-S8 in example one.

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

-2.9758E-04

4.9752E-05

-4.5661E-05

1.6119E-05

-3.1805E-06

3.3497E-07

-1.4430E-08

S2

3.3412E-03

-1.0952E-03

3.9242E-04

-9.3338E-05

1.2928E-05

-8.9307E-07

2.0172E-08

S3

-4.5680E-03

-6.0091E-04

2.9237E-04

-2.9838E-05

-1.1731E-05

3.4353E-06

-2.7497E-07

S4

-1.2774E-02

-1.3143E-04

-3.1861E-05

1.0616E-04

-8.0154E-05

1.9027E-05

-1.7292E-06

S5

2.7172E-02

-6.7446E-03

4.1425E-03

-1.5206E-03

2.8011E-04

-1.9668E-05

-1.9503E-07

S6

8.3964E-03

4.1010E-03

-2.9559E-04

-3.9392E-04

1.1433E-04

-1.0022E-05

1.5694E-07

S7

-2.4074E-02

7.3976E-03

-7.8259E-04

-4.4918E-04

1.6324E-04

-2.0072E-05

8.6723E-07

S8

-1.8344E-02

2.8676E-03

2.0416E-04

-3.1525E-04

8.0744E-05

-8.9789E-06

3.8446E-07

TABLE 2

Fig. 2 shows an axial chromatic aberration curve of the optical lens assembly of the first example, which shows the deviation of the convergent focus of light rays with different wavelengths after passing through the optical lens assembly. Fig. 3 shows a chromatic aberration of magnification curve of the optical lens assembly of the first example, which shows the deviation of different image heights of the light passing through the optical lens assembly on the image plane. FIG. 4 shows astigmatism curves for the first example set of optical lenses representing meridional field curvature and sagittal field curvature. Fig. 5 shows distortion curves of the optical lens assembly of the first example, which show distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 2 to 5, the optical lens assembly of the example one can achieve good imaging quality.

Example two

Fig. 6 to 10 show an optical lens assembly according to the second embodiment of the present application. In this example and the following examples, descriptions of parts similar to example one will be omitted for the sake of brevity. Fig. 6 is a schematic diagram illustrating a structure of an optical lens set of example two.

As shown in fig. 6, the optical lens assembly sequentially includes, from the light incident side to the light exiting side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

The first lens E1 has positive power, and the surface S1 of the first lens near the incident side is a convex surface, and the surface S2 of the first lens near the exit side is a convex surface. The second lens E2 has negative power, the surface S3 of the second lens near the incident side is convex, and the surface S4 of the second lens near the exit side is concave. The third lens E3 has positive optical power, and the surface S5 of the third lens near the incident side is a concave surface, and the surface S6 of the third lens near the exit side is a convex surface. The fourth lens E4 has positive power, and the surface S7 of the fourth lens near the incident side is a concave surface, and the surface S8 of the fourth lens near the exit side is a convex surface. The filter E5 has a face S9 on the incident side of the filter and a face S10 on the emission side of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging surface S11.

In this example, the effective focal length f of the optical lens group is 17.41mm, the total system length TTL of the optical lens group is 11.70mm, and the optical back focus BFL is 18.20 mm.

Table 3 shows a table of basic structural parameters of the optical lens assembly of example two, wherein the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are all millimeters (mm).

TABLE 3

Table 4 shows the high-order term coefficients that can be used for each aspherical mirror surface in example two, wherein each aspherical mirror surface type can be defined by formula (1) given in example one above.

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

2.6386E-05

1.8180E-06

-9.7200E-06

5.6677E-07

2.0288E-07

-3.7927E-08

1.7720E-09

S2

5.4567E-03

-2.2177E-03

5.8072E-04

-9.0825E-05

8.0627E-06

-3.7251E-07

6.9405E-09

S3

-3.1155E-03

-6.5222E-04

-1.5847E-04

1.7438E-04

-4.9217E-05

6.3029E-06

-3.2084E-07

S4

-1.2706E-02

1.6119E-03

-1.4598E-03

7.3004E-04

-2.3683E-04

4.1522E-05

-3.3057E-06

S5

1.5115E-02

-1.3786E-03

5.5938E-04

6.3328E-05

-1.5225E-04

4.8219E-05

-5.0287E-06

S6

5.1885E-03

1.6480E-03

5.9930E-04

-5.5924E-04

1.2889E-04

-9.9572E-06

6.6049E-08

S7

-1.3113E-02

1.8930E-03

1.0351E-03

-8.3125E-04

2.1301E-04

-2.3720E-05

9.8137E-07

S8

-9.4437E-03

3.3307E-04

5.2214E-04

-2.6608E-04

5.6506E-05

-5.7457E-06

2.3284E-07

TABLE 4

Fig. 7 shows an axial chromatic aberration curve of the optical lens assembly of example two, which shows the deviation of the convergence focus of light rays with different wavelengths after passing through the optical lens assembly. Fig. 8 shows a chromatic aberration of magnification curve of the optical lens assembly of the second example, which shows the deviation of different image heights of the light passing through the optical lens assembly on the image plane. FIG. 9 shows astigmatism curves of the second set of optical lenses, representing meridional field curvature and sagittal field curvature. Fig. 10 shows distortion curves of the optical lens assembly of example two, which show values of distortion magnitudes for different angles of view.

As can be seen from fig. 7 to 10, the optical lens assembly of example two can achieve good imaging quality.

Example III

As shown in fig. 11 to 15, an optical lens assembly of example three of the present application is described. Fig. 11 is a schematic diagram illustrating a structure of an optical lens set of example three.

As shown in fig. 11, the optical lens assembly sequentially includes, from the light incident side to the light exiting side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

In this example, the effective focal length f of the optical lens group is 17.41mm, the total system length TTL of the optical lens group is 11.11mm, and the optical back focus BFL is 18.21 mm.

Table 5 shows a table of basic structural parameters of the optical lens group of example three, wherein the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are all millimeters (mm).

TABLE 5

Table 6 shows the high-order term coefficients that can be used for each aspherical mirror surface in example three, wherein each aspherical mirror surface type can be defined by formula (1) given in example one above.

TABLE 6

Fig. 12 shows an axial chromatic aberration curve of the optical lens assembly of example three, which shows the deviation of the convergent focus of light rays of different wavelengths after passing through the optical lens assembly. Fig. 13 shows a chromatic aberration of magnification curve of the optical lens assembly of example three, which shows the deviation of different image heights of the light passing through the optical lens assembly on the image plane. FIG. 14 shows astigmatism curves for the optical lens group of example three, which represent meridional field curvature and sagittal field curvature. Fig. 15 shows distortion curves of the optical lens group of example three, which show values of distortion magnitudes for different angles of view.

As can be seen from fig. 12 to 15, the optical lens assembly of the third example can achieve good imaging quality.

Example four

As shown in fig. 16 to 20, an optical lens assembly of example four of the present application is described. Fig. 16 is a schematic diagram of an optical lens set structure in example four.

As shown in fig. 16, the optical lens assembly sequentially includes, from the light incident side to the light exiting side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

In this example, the effective focal length f of the optical lens group is 17.40mm, the total system length TTL of the optical lens group is 11.42mm, and the optical back focus BFL is 18.26 mm.

Table 7 shows a table of basic structural parameters of the optical lens group of example four, in which the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are all millimeters (mm).

TABLE 7

Table 8 shows the high-order term coefficients that can be used for each aspherical mirror surface in example four, wherein each aspherical mirror surface type can be defined by formula (1) given in example one above.

Flour mark

A4

A6

A8

A10

A12

A14

S1

-4.5317E-04

3.6560E-05

-5.0826E-05

2.2906E-05

-6.0215E-06

9.2455E-07

S2

1.7292E-03

-7.6012E-05

-1.3743E-05

1.0899E-05

-2.6564E-06

3.3801E-07

S5

3.3950E-02

5.4852E-04

-1.4209E-02

2.7398E-02

-2.9996E-02

2.1727E-02

S6

3.5892E-02

-3.2054E-02

4.0810E-02

-3.6979E-02

2.4670E-02

-1.1990E-02

S7

-5.9136E-03

-2.0759E-02

2.7615E-02

-2.2918E-02

1.3652E-02

-5.9064E-03

S8

-2.0957E-02

5.6093E-03

-3.4384E-03

2.5475E-03

-1.3751E-03

4.8780E-04

Flour mark

A16

A18

A20

A22

A24

A26

S1

-7.6151E-08

2.6146E-09

0.0000E+00

S2

-1.9626E-08

3.1209E-10

0.0000E+00

S5

-1.0768E-02

3.6651E-03

-8.4128E-04

1.2414E-04

-1.0602E-05

3.9663E-07

S6

4.1857E-03

-1.0278E-03

1.7156E-04

-1.8346E-05

1.1189E-06

-2.9035E-08

S7

1.8232E-03

-3.8854E-04

5.4008E-05

-4.3882E-06

1.5765E-07

0.0000E+00

S8

-1.1163E-04

1.5859E-05

-1.2709E-06

4.3892E-08

0.0000E+00

TABLE 8

Fig. 17 shows an axial chromatic aberration curve of the optical lens assembly of example four, which shows the deviation of the convergent focus of light rays of different wavelengths after passing through the optical lens assembly. Fig. 18 shows a chromatic aberration of magnification curve of the optical lens assembly of example four, which shows the deviation of different image heights of the light beam on the image plane after passing through the optical lens assembly. FIG. 19 shows astigmatism curves for the optical lens group of example four, representing meridional and sagittal image planes curvature. Fig. 20 shows a distortion curve of the optical lens assembly of example four, which shows values of distortion magnitudes corresponding to different angles of view.

As can be seen from fig. 17 to 20, the optical lens assembly of example four can achieve good imaging quality.

Example five

Fig. 21 to 25 show an optical lens assembly according to example five of the present application. Fig. 21 is a schematic diagram illustrating a structure of an optical lens group in example five.

As shown in fig. 21, the optical lens assembly sequentially includes, from the light incident side to the light exiting side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

The first lens E1 has positive power, and the surface S1 of the first lens near the incident side is a convex surface, and the surface S2 of the first lens near the exit side is a convex surface. The second lens E2 has negative power, the surface S3 of the second lens near the incident side is convex, and the surface S4 of the second lens near the exit side is concave. The third lens E3 has negative power, and the surface S5 of the third lens near the incident side is a concave surface, and the surface S6 of the third lens near the exit side is a convex surface. The fourth lens E4 has positive power, and the surface S7 of the fourth lens near the incident side is a concave surface, and the surface S8 of the fourth lens near the exit side is a convex surface. The filter E5 has a face S9 on the incident side of the filter and a face S10 on the emission side of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging surface S11.

In this example, the effective focal length f of the optical lens group is 17.42mm, the total system length TTL of the optical lens group is 11.69mm, and the optical back focus BFL is 18.28 mm.

Table 9 shows a table of basic structural parameters for the optical lens set of example five, wherein the radius of curvature, thickness/distance, focal length, and effective radius are all in millimeters (mm).

TABLE 9

Table 10 shows the high-order term coefficients that can be used for each aspherical mirror surface in example five, wherein each aspherical mirror surface type can be defined by formula (1) given in example one above.

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

S1

1.2342E-04

-1.4137E-05

6.0268E-07

-2.3558E-06

1.7022E-07

7.5137E-08

-1.2687E-08

5.1984E-10

S2

5.2494E-03

-7.7348E-04

-4.7776E-04

2.7375E-04

-6.2839E-05

7.7179E-06

-5.0304E-07

1.3536E-08

S3

-4.5590E-03

9.6832E-04

-8.4268E-04

1.6690E-04

3.4476E-05

-1.8534E-05

2.7221E-06

-1.4266E-07

S4

-1.4688E-02

1.8293E-03

-1.3832E-04

-9.3617E-04

6.9129E-04

-2.3189E-04

3.8614E-05

-2.6755E-06

S5

1.3365E-02

-1.4095E-03

1.6380E-03

-1.2080E-03

5.9634E-04

-1.9482E-04

3.6253E-05

-2.8739E-06

S6

-1.7986E-03

7.5929E-03

-2.9228E-03

7.0930E-04

-1.1453E-04

2.7969E-06

2.8114E-06

-3.2618E-07

S7

-1.7815E-02

6.7816E-03

-2.1540E-03

4.8030E-04

-1.0394E-04

1.3715E-05

1.2258E-07

-1.2614E-07

S8

-9.1302E-03

-8.8615E-06

7.6789E-04

-3.8757E-04

9.9153E-05

-1.5662E-05

1.5425E-06

-7.1614E-08

Watch 10

Fig. 22 shows an axial chromatic aberration curve of the optical lens group of example five, which shows the deviation of the convergent focus of light rays of different wavelengths after passing through the optical lens group. Fig. 23 shows a chromatic aberration of magnification curve of the optical lens assembly of example five, which shows the deviation of different image heights of light rays on the image plane after passing through the optical lens assembly. FIG. 24 shows astigmatism curves for the optical lens group of example five, representing meridional and sagittal image planes curvature. Fig. 25 shows distortion curves of the optical lens group of example five, which show values of distortion magnitudes for different angles of view.

As can be seen from fig. 22 to 25, the optical lens assembly of example five can achieve good imaging quality.

Example six

As shown in fig. 26 to 30, an optical lens set according to example six of the present application is described. Fig. 26 is a schematic diagram illustrating an optical lens group structure of example six.

As shown in fig. 26, the optical lens assembly sequentially includes, from the light incident side to the light exiting side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

The first lens E1 has positive power, and the surface S1 of the first lens near the incident side is a convex surface, and the surface S2 of the first lens near the exit side is a convex surface. The second lens E2 has negative power, the surface S3 of the second lens near the incident side is convex, and the surface S4 of the second lens near the exit side is concave. The third lens E3 has positive power, and the surface S5 of the third lens near the incident side is a convex surface, and the surface S6 of the third lens near the exit side is a convex surface. The fourth lens E4 has positive power, and the surface S7 of the fourth lens near the incident side is a concave surface, and the surface S8 of the fourth lens near the exit side is a convex surface. The filter E5 has a face S9 on the incident side of the filter and a face S10 on the emission side of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging surface S11.

In this example, the effective focal length f of the optical lens group is 17.40mm, the total system length TTL of the optical lens group is 12.24mm and the optical back focus BFL is 18.40 mm.

Table 11 shows a basic structural parameter table of the optical lens group of example six, in which the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are all millimeters (mm).

TABLE 11

Table 12 shows the high-order term coefficients that can be used for each of the aspherical mirror surfaces in example six, wherein each aspherical mirror surface type can be defined by formula (1) given in example one above.

Flour mark	A4	A6	A8	A10	A12
						S1	-6.8781E-04	3.6170E-04	-4.1285E-05	-1.6106E-05	6.9087E-06
S2	7.3567E-03	-2.0500E-03	4.6639E-04	-1.5470E-04	4.8168E-05
						S3	-1.2440E-02	-1.7537E-03	3.0289E-04	0.0000E+00	0.0000E+00
S4	-3.6506E-02	0.0000E+00	0.0000E+00	0.0000E+00	0.0000E+00
						S5	1.0812E-02	-3.5198E-03	7.3922E-04	-1.7084E-04	5.0528E-06
S6	4.2936E-03	-2.5212E-03	2.7545E-03	-2.8847E-03	1.9647E-03
						Flour mark	A14	A16	A18	A20	A22
S1	-1.1834E-06	9.9163E-08	-3.1586E-09	0.0000E+00	0.0000E+00
						S2	-9.4552E-06	1.0253E-06	-4.5679E-08	0.0000E+00	0.0000E+00
S3	0.0000E+00	0.0000E+00	0.0000E+00	0.0000E+00	0.0000E+00
						S4	0.0000E+00	0.0000E+00	0.0000E+00	0.0000E+00	0.0000E+00
S5	2.7389E-06	-2.6225E-07	0.0000E+00	0.0000E+00	0.0000E+00
						S6	-8.5937E-04	2.3905E-04	-4.0919E-05	3.9342E-06	-1.6275E-07

TABLE 12

Fig. 27 shows an on-axis chromatic aberration curve of the optical lens group of example six, which shows the deviation of the convergent focus of light rays of different wavelengths after passing through the optical lens group. Fig. 28 is a chromatic aberration of magnification curve of the optical lens assembly of example six, which shows the deviation of different image heights of light passing through the optical lens assembly on the image plane. FIG. 29 shows astigmatism curves for the optical lens group of example six, which represent meridional field curvature and sagittal field curvature. Fig. 30 shows distortion curves of the optical lens group of example six, which show values of distortion magnitudes for different angles of view.

As can be seen from fig. 27 to 30, the optical lens assembly of example six can achieve good imaging quality.

Example seven

Fig. 31 to 35 show an optical lens assembly according to example seven of the present application. Fig. 31 is a schematic diagram of an optical lens group structure of example seven.

As shown in fig. 31, the optical lens assembly sequentially includes, from the light incident side to the light exiting side: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a filter E5 and an image plane S11.

The first lens E1 has positive power, and the surface S1 of the first lens near the incident side is a convex surface, and the surface S2 of the first lens near the exit side is a convex surface. The second lens E2 has negative power, the surface S3 of the second lens near the incident side is a concave surface, and the surface S4 of the second lens near the exit side is a concave surface. The third lens E3 has positive power, and the surface S5 of the third lens near the incident side is a convex surface, and the surface S6 of the third lens near the exit side is a convex surface. The fourth lens E4 has negative power, and the surface S7 of the fourth lens near the incident side is a concave surface, and the surface S8 of the fourth lens near the exit side is a convex surface. The filter E5 has a face S9 on the incident side of the filter and a face S10 on the emission side of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging surface S11.

In this example, the effective focal length f of the optical lens group is 17.40mm, the total system length TTL of the optical lens group is 10.40mm, and the optical back focus BFL is 18.44 mm.

Table 13 shows a table of basic structural parameters of the optical lens group of example seven, in which the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are all millimeters (mm).

Watch 13

Table 14 shows the high-order term coefficients that can be used for each of the aspherical mirror surfaces in example seven, wherein each of the aspherical mirror surface types can be defined by formula (1) given in example one above.

TABLE 14

Fig. 32 shows an on-axis chromatic aberration curve of the optical lens group of example seven, which shows the deviation of the convergent focus of light rays of different wavelengths after passing through the optical lens group. Fig. 33 is a chromatic aberration of magnification curve of the optical lens assembly of example seven, which shows the deviation of different image heights of light rays passing through the optical lens assembly on the image plane. FIG. 34 shows the astigmatism curves for the set of optical lenses of example seven, representing meridional and sagittal image planes curvature. Fig. 35 shows a distortion curve of the optical lens group of example seven, which shows values of distortion magnitudes corresponding to different angles of view.

As can be seen from fig. 32 to 35, the optical lens assembly of example seven can achieve good imaging quality.

To sum up, examples one to seven respectively satisfy the relationships shown in table 15.

Conditional formula/example	1	2	3	4	5	6	7
								f/TTL	0.93	0.96	0.96	0.95	0.95	0.95	0.94
BFL/f	0.67	0.67	0.64	0.66	0.67	0.70	0.60
								BFL/TTL	0.62	0.64	0.61	0.63	0.64	0.66	0.56
SD/TD	0.72	0.71	0.75	0.68	0.71	0.68	0.58
								f1/f	0.46	0.43	0.46	0.39	0.43	0.36	0.50
R1/f1	0.77	0.67	0.65	0.72	0.67	0.91	0.57
								T23/∑AT	0.94	0.94	0.93	0.87	0.95	0.82	0.52
CT2/CT3	0.92	0.77	1.06	1.00	0.70	0.56	0.64
								CT1/∑CT	0.41	0.40	0.37	0.40	0.40	0.41	0.48
V2/V1	0.42	0.42	0.42	0.49	0.42	0.49	0.49
								N3/N2	0.94	0.94	1.00	0.88	0.94	0.88	1.07
DT42/DT11	0.69	0.86	0.90	0.78	0.87	0.86	0.76
								∑ET/∑CT	0.87	0.85	0.84	0.87	0.85	0.87	0.89
ET2/ET1	0.93	1.03	1.20	1.14	0.99	1.04	0.80
								ET2/CT2	1.27	1.30	1.31	1.21	1.31	1.73	1.56
CT_MAX/CT_MIN	2.65	2.27	2.12	2.33	2.29	2.85	4.11

Watch 15

Table 16 shows the effective focal lengths f of the optical lens groups of examples one to seven, the effective focal lengths f1 to f4 of the respective lenses, and the like.

TABLE 16

The present application also provides an imaging device whose electron photosensitive element may be a photo-coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device may be a stand-alone imaging device such as a digital camera, or may be an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical lens set described above.

It is to be understood that the above-described embodiments are only a few, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical lens assembly, comprising, in order from a light incident side to a light exiting side along an optical axis:

the surface of the first lens, which is close to the incident side, is a convex surface, and the surface of the first lens, which is close to the emergent side, is a convex surface;

a diaphragm;

a second lens;

a third lens;

a fourth lens;

the effective focal length f of the optical lens group and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following condition: 0.9< f/TTL < 1; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8.

2. The optical lens group of claim 1, wherein an axial distance BFL from a surface of the fourth lens element near the exit side to the imaging plane and an axial distance TTL from a surface of the first lens element near the entrance side to the imaging plane satisfy: 0.5< BFL/TTL < 0.7.

3. The set of optical lenses of claim 1, wherein a distance SD on the optical axis from the stop to the exit-side surface of the fourth lens element and a distance TD on the optical axis from the entrance-side surface of the first lens element to the exit-side surface of the fourth lens element satisfy: 0.5< SD/TD < 0.8.

4. The set of optical lenses of claim 1, wherein an effective focal length f1 of the first lens and an effective focal length f of the first lens satisfy: 0.3< f1/f < 0.6.

5. The set of optical lenses of claim 1, wherein an effective focal length f1 of the first lens and a radius of curvature R1 of a face of the first lens closer to the incident side satisfy: 0.5< R1/f1< 1.

6. The optical lens group of claim 1, characterized in that an air space T23 on the optical axis of the second lens and the third lens and a sum Σ AT of air spaces on the optical axis between adjacent two of the first lens to the fourth lens satisfy: 0.5< T23/∑ AT <1.

7. The optical lens set of claim 1, wherein a center thickness CT2 of the second lens on the optical axis and a center thickness CT3 of the third lens on the optical axis satisfy: 0.5< CT2/CT3< 1.1.

8. The optical lens set of claim 1, wherein a center thickness CT1 of the first lens on the optical axis and a sum Σ CT of center thicknesses of the first to fourth lenses on the optical axis satisfy: 0.35< CT1/∑ CT < 0.5.

9. The set of optical lenses of claim 1, wherein an abbe number V1 of the first lens and an abbe number V2 of the second lens satisfy: 0.4< V2/V1< 0.5.

10. An optical lens assembly, comprising, in order from a light incident side to a light exiting side along an optical axis:

a diaphragm;

a second lens;

a third lens;

a fourth lens;

the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the effective focal length f of the optical lens group meet the following requirements: 0.6< BFL/f < 0.8; the axial distance BFL from the surface of the fourth lens close to the emergent side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy the following conditions: 0.5< BFL/TTL < 0.7.