CN114675396A

CN114675396A - Imaging system

Info

Publication number: CN114675396A
Application number: CN202111487181.1A
Authority: CN
Inventors: 周雨; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2021-12-07
Filing date: 2021-12-07
Publication date: 2022-06-28
Anticipated expiration: 2041-12-07
Also published as: CN114675396B

Abstract

The invention provides an imaging system. The light source device sequentially comprises the following components from the light inlet side of the imaging system to the light outlet side of the imaging system: a diaphragm; the surface of the first lens, which is close to the light incidence side, is in a convex shape; the surface of the second lens close to the light incidence side is convex; a third lens; the surface of the fourth lens, which is close to the light incidence side, is in a convex shape; a fifth lens element with positive refractive power; the surface of the sixth lens, which is close to the light incidence side, is in a concave shape; the on-axis distance SAG51 from the intersection point of the surface of the fifth lens close to the light inlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light inlet side, and the on-axis distance SAG52 from the intersection point of the surface of the fifth lens close to the light outlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light outlet side satisfy the following conditions: -4.5 < (SAG51+ SAG52)/(SAG51-SAG52) < -2.0. The invention solves the problem that the imaging system in the prior art cannot give consideration to low cost and high image quality.

Description

Imaging system

Technical Field

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

Background

With the development of electronic products such as mobile phones and flat panels, the lens has a development trend towards large image plane, large wide angle, large aperture and ultra-thin. And for some electronic products, the image plane tends to be large, and the cost of the lens is also considered. The large image plane means higher resolution, the low-cost high-performance mobile phone lens undoubtedly provides higher difficulty challenges for the design of an optical system, but the imaging capability and the competitive advantage of the mobile phone lens are greatly improved, the structure of the traditional five-piece type lens is not enough to effectively meet the challenges, the cost of the seven-piece type imaging system is obviously increased, and the six-piece type imaging system gradually becomes the mainstream.

That is, the imaging system in the prior art has the problem that the low cost and the high image quality cannot be compatible.

Disclosure of Invention

The invention mainly aims to provide an imaging system to solve the problem that the imaging system in the prior art cannot give consideration to low cost and high image quality.

In order to achieve the above object, according to one aspect of the present invention, there is provided an imaging system, comprising in sequence from an entrance side of the imaging system to an exit side of the imaging system: a diaphragm; the surface of the first lens, which is close to the light incidence side, is in a convex shape; the surface of the second lens, which is close to the light incidence side, is in a convex shape; a third lens element with refractive power; the surface of the fourth lens, which is close to the light incidence side, is in a convex shape; a fifth lens element with positive refractive power; the surface of the sixth lens, which is close to the light incidence side, is in a concave shape; the on-axis distance SAG51 from the intersection point of the surface of the fifth lens close to the light inlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light inlet side, and the on-axis distance SAG52 from the intersection point of the surface of the fifth lens close to the light outlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light outlet side satisfy the following conditions: -4.5 < (SAG51+ SAG52)/(SAG51-SAG52) < -2.0.

Further, the maximum field angle FOV of the imaging system satisfies: FOV >80 deg.

Further, the effective focal length f of the imaging system and the entrance pupil diameter EPD of the imaging system satisfy: f/EPD is less than or equal to 1.9.

Furthermore, the on-axis distance TTL from the surface of the first lens near the light entrance side to the imaging plane of the imaging system and the half ImgH of the diagonal length of the effective pixel area on the imaging plane satisfy: TTL/ImgH is less than 1.2.

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 light inlet side satisfy that: 2.0 < f1/R1 < 2.5.

Further, the effective focal length f1 of the first lens and the curvature radius R2 of the surface of the first lens close to the light-emitting side satisfy that: r2/f1 is more than 1.5 and less than 2.0.

Further, the effective focal length f2 of the second lens and the curvature radius R4 of the surface of the second lens close to the light-emitting side satisfy that: -3.5 < f2/R4 < -2.0.

Further, the curvature radius R7 of the surface of the fourth lens close to the light inlet side and the curvature radius R8 of the surface of the fourth lens close to the light outlet side satisfy that: R7/R8 is more than or equal to 1.0 and less than or equal to 1.6.

Further, the effective focal length f5 of the fifth lens and the curvature radius R10 of the surface of the fifth lens close to the light-emitting side satisfy that: -2.0 < f5/R10 < -1.0.

Further, the curvature radius R11 of the surface of the sixth lens close to the light inlet side and the curvature radius R12 of the surface of the sixth lens close to the light outlet side satisfy that: -3.5 < R11/R12 < -3.0.

Further, the central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 2.5 < CT1/ET1 < 3.0.

Further, the central thickness CT5 of the fifth lens on the optical axis and the edge thickness ET5 of the fifth lens satisfy: 2.0 < CT5/ET5 < 3.0.

Further, the air interval T12 on the optical axis, the on-axis distance SAG12 between the intersection point of the surface of the first lens close to the light-emitting side and the optical axis and the effective radius vertex of the surface of the first lens close to the light-emitting side satisfy between the first lens and the second lens: 1.0 < T12/SAG12 < 2.0.

Further, the air interval T23 on the optical axis, the on-axis distance SAG22 from the intersection point of the surface of the second lens close to the light-emitting side and the optical axis to the effective radius vertex of the surface of the second lens close to the light-emitting side, and the air interval T23 on the optical axis of the second lens and the third lens satisfy: 1.5 < T23/SAG22 < 2.6.

Further, an on-axis distance SAG62 between an intersection point of a surface of the sixth lens on the light exit side and the optical axis to an effective radius vertex of the surface of the sixth lens on the light exit side, and an air interval T56 on the optical axis of the fifth lens and the sixth lens satisfy: -2.0 < SAG62/T56 < -1.0.

Further, the abbe number V2 of the second lens and the abbe number V3 of the third lens satisfy: V3-V2 < 20.

Further, the abbe number V3 of the third lens and the abbe number V4 of the fourth lens satisfy: V3-V4 < 15.

According to another aspect of the present invention, there is provided an imaging system, comprising in sequence from an entrance side of the imaging system to an exit side of the imaging system: a diaphragm; the surface of the first lens, which is close to the light inlet side, is in a convex shape; the surface of the second lens, which is close to the light inlet side, is in a convex shape; a third lens element with refractive power; the surface of the fourth lens, which is close to the light incidence side, is in a convex shape; a fifth lens element with positive refractive power; the surface, close to the light inlet side, of the sixth lens is concave; wherein, the air interval T12 between the first lens and the second lens on the optical axis, the on-axis distance SAG12 between the intersection point of the surface of the first lens close to the light-emitting side and the optical axis and the effective radius vertex of the surface of the first lens close to the light-emitting side satisfy the following conditions: 1.0 < T12/SAG12 < 2.0.

Further, the maximum field angle FOV of the imaging system satisfies: FOV > 80.

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 light entrance side satisfy the following condition: 2.0 < f1/R1 < 2.5.

By applying the technical scheme of the invention, the imaging system sequentially comprises a diaphragm, a first lens with refractive power, a second lens with refractive power, a third lens with refractive power, a fourth lens with refractive power, a fifth lens with positive refractive power and a sixth lens with refractive power from the light-in side of the imaging system to the light-out side of the imaging system, wherein the surface of the first lens, which is close to the light-in side, is in a convex shape; the surface of the second lens close to the light incident side is convex; the surface of the fourth lens close to the light incidence side is convex; the surface of the sixth lens close to the light incident side is concave; the on-axis distance SAG51 from the intersection point of the surface of the fifth lens close to the light inlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light inlet side, and the on-axis distance SAG52 from the intersection point of the surface of the fifth lens close to the light outlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light outlet side satisfy the following conditions: -4.5 < (SAG51+ SAG52)/(SAG51-SAG52) < -2.0.

By reasonably controlling the positive and negative distribution of the refractive power of each lens of the imaging system, the low-order aberration of the imaging system can be effectively balanced, the tolerance sensitivity of the imaging system can be reduced, the miniaturization of the imaging system is kept, and the imaging quality of the imaging system is ensured. The distance on the axis between the effective radius summit of the surface of the fifth lens close to the light inlet side and the intersection point of the optical axis to the surface of the fifth lens close to the light inlet side and the distance on the axis between the effective radius summit of the surface of the fifth lens close to the light outlet side and the intersection point of the surface of the fifth lens close to the light outlet side and the effective radius summit of the optical axis can reasonably control the deflection angle of the chief ray, improve the matching degree with the chip and are beneficial to adjusting the structure of the optical lens group. The imaging system in this application has six lens greatly increased imaging system's formation of image quality, can not transition simultaneously and increase imaging system's cost, has the advantage of low-cost and high image quality.

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 shows a schematic configuration diagram of an imaging system of example one of the present invention;

FIGS. 2-5 illustrate an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve, respectively, of the imaging system of FIG. 1;

fig. 6 is a schematic configuration diagram showing an imaging system of example two of the present invention;

FIGS. 7-10 illustrate on-axis chromatic aberration curves, astigmatism curves, distortion curves, and magnification chromatic aberration curves, respectively, of the imaging system of FIG. 6;

fig. 11 is a schematic configuration diagram showing an imaging system of example three of the present invention;

fig. 12 to 15 show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve, respectively, of the imaging system in fig. 11;

fig. 16 is a schematic configuration diagram showing an imaging system of example four of the present invention;

fig. 17 to 20 show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve, respectively, of the imaging system in fig. 16;

fig. 21 is a schematic structural view showing an imaging system of example five of the present invention;

fig. 22 to 25 show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the imaging system in fig. 21.

Wherein the figures include the following reference numerals:

STO, stop; e1, first lens; s1, the surface of the first lens close to the light incidence side; s2, the surface of the first lens close to the light-emitting side; e2, second lens; s3, the surface of the second lens close to the light incidence side; s4, the surface of the second lens close to the light-emitting side; e3, third lens; s5, the surface of the third lens close to the light incidence side; s6, the surface of the third lens close to the light-emitting side; e4, fourth lens; s7, the surface of the fourth lens close to the light incidence side; s8, the surface of the fourth lens close to the light-emitting side; e5, fifth lens; s9, the surface of the fifth lens close to the light incidence side; s10, the surface of the fifth lens close to the light-emitting side; e6, sixth lens; s11, the surface of the sixth lens close to the light incidence side; s12, the surface of the sixth lens close to the light-emitting side; e7, a filter plate; s13, the light incident side surface of the filter plate; s14, the light-emitting side surface of the filter plate; and S15, 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, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for 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 object side becomes the surface of the lens close to the light inlet side, and the surface of each lens close to the image side is called the surface of the lens close to the light outlet side. The determination of the surface shape in the paraxial region can be performed by determining whether or not the surface shape is concave or convex, based on the R value (R denotes the radius of curvature of the paraxial region, and usually denotes the R value in a lens database (lens data) in optical software) in accordance with the determination method of a person ordinarily skilled in the art. When the R value is positive, the object side is judged to be convex, and when the R value is negative, the object side is judged to be concave; when the R value is positive, the image side surface is determined to be concave, and when the R value is negative, the image side surface is determined to be convex.

The invention provides an imaging system, aiming at solving the problem that the imaging system in the prior art cannot give consideration to low cost and high image quality.

As shown in fig. 1 to 25, the aperture stop, the first lens element with refractive power, the second lens element with refractive power, the third lens element with refractive power, the fourth lens element with refractive power, the fifth lens element with positive refractive power and the sixth lens element with refractive power are sequentially disposed along the light incident side of the imaging system to the light exiting side of the imaging system, and the surface of the first lens element near the light incident side is convex; the surface of the second lens close to the light incidence side is convex; the surface of the fourth lens close to the light incidence side is convex; the surface of the sixth lens close to the light incident side is concave; the on-axis distance SAG51 from the intersection point of the surface of the fifth lens close to the light inlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light inlet side, and the on-axis distance SAG52 from the intersection point of the surface of the fifth lens close to the light outlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light outlet side satisfy the following conditions: -4.5 < (SAG51+ SAG52)/(SAG51-SAG52) < -2.0.

By reasonably controlling the positive and negative distribution of the refractive power of each lens of the imaging system, the low-order aberration of the imaging system can be effectively balanced, the tolerance sensitivity of the imaging system can be reduced, the miniaturization of the imaging system is kept, and the imaging quality of the imaging system is ensured. The distance on the axis between the effective radius summit of the surface of the fifth lens close to the light inlet side and the intersection point of the optical axis to the surface of the fifth lens close to the light inlet side and the distance on the axis between the effective radius summit of the surface of the fifth lens close to the light outlet side and the intersection point of the surface of the fifth lens close to the light outlet side and the effective radius summit of the optical axis can reasonably control the deflection angle of the chief ray, improve the matching degree with the chip and are beneficial to adjusting the structure of the optical lens group. The imaging system in the application has the advantages that the imaging quality of the imaging system is greatly improved by the six lenses, meanwhile, the cost of the imaging system cannot be increased in a transition mode, and the imaging system is low in cost and high in image quality.

Preferably, an on-axis distance SAG51 from an intersection point of a surface of the fifth lens close to the light incident side and the optical axis to an effective radius vertex of the surface of the fifth lens close to the light incident side, and an on-axis distance SAG52 from an intersection point of the surface of the fifth lens close to the light exit side and the optical axis to an effective radius vertex of the surface of the fifth lens close to the light exit side satisfy: -4.3 < (SAG51+ SAG52)/(SAG51-SAG52) < -2.1.

In the present embodiment, the maximum field angle FOV of the imaging system satisfies: FOV >80 deg. The wide-field-of-view imaging system is large in field angle and wide in shooting field of view, so that the imaging system can clearly image a large range of shooting, and the wide-field-of-view imaging system has the advantage of being large in image plane. Preferably, the FOV is >87 °.

In the present embodiment, the effective focal length f of the imaging system and the entrance pupil diameter EPD of the imaging system satisfy: f/EPD is less than or equal to 1.9. The effective focal length and the entrance pupil diameter of the imaging system are reasonably controlled, so that the imaging system obtains a larger light-passing aperture. The light-passing caliber is enlarged, so that the lighting can be improved, the noise point can be reduced under the condition of darkness, and the imaging quality is improved. Preferably, 1.8< f/EPD ≦ 1.9.

In this embodiment, an on-axis distance TTL from a surface of the first lens closer to the light incident side to an imaging plane of the imaging system and a half ImgH of a diagonal length of an effective pixel area on the imaging plane satisfy: TTL/ImgH is less than 1.2. The ratio of the distance from the surface of the first lens close to the light incidence side to the imaging surface on the axis to the half of the diagonal length of the effective pixel area on the imaging surface is reasonably set, so that the imaging system is ensured to have the characteristic of being light and thin, and the miniaturization of the imaging system is facilitated. Preferably, 1.1 < TTL/ImgH < 1.2.

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 near the light entrance side satisfy: 2.0 < f1/R1 < 2.5. The ratio of the effective focal length of the first lens to the curvature radius of the surface, close to the light incidence side, of the first lens is reasonably set, so that the processing sensitivity of the first lens is reduced while the performance of an imaging system is ensured. Preferably, 2.2 < f1/R1 < 2.4.

In the present embodiment, the effective focal length f1 of the first lens and the radius of curvature R2 of the surface of the first lens near the light exit side satisfy: 1.5 < R2/f1 < 2.0. By limiting R2/f1 within a reasonable range, the reasonable setting of the effective focal length of the first lens is facilitated, the overall focal length of the imaging system is increased, and the imaging system has a large image plane. Preferably, 1.55 < R2/f1 < 1.8.

In the present embodiment, the effective focal length f2 of the second lens and the curvature radius R4 of the surface of the second lens near the light exit side satisfy: -3.5 < f2/R4 < -2.0. By limiting f2/R4 within a reasonable range, the effective focal length of the second lens is reasonably set, the light ray position is adjusted, the total length of the imaging system is shortened, and the miniaturization of the imaging system is facilitated. Preferably, -3.3 < f2/R4 < -2.3.

In the present embodiment, a curvature radius R7 of a surface of the fourth lens on the light incident side and a curvature radius R8 of a surface of the fourth lens on the light exiting side satisfy: R7/R8 is more than or equal to 1.0 and less than or equal to 1.6. By limiting R7/R8 within a reasonable range, the incidence angle of the off-axis field rays on an imaging surface can be controlled, and the matching performance with a photosensitive element and a band-pass filter is improved. Preferably, 1.0. ltoreq.R 7/R8 < 1.55.

In the present embodiment, an effective focal length f5 of the fifth lens and a radius of curvature R10 of a surface of the fifth lens on the light exit side satisfy: -2.0 < f5/R10 < -1.0. The ratio of the effective focal length of the fifth lens to the curvature radius of the surface, close to the light-emitting side, of the fifth lens is restricted to be within a certain range, and the imaging system is favorable to have good imaging quality. Preferably, -1.9 < f5/R10 < -1.1.

In the present embodiment, a curvature radius R11 of a surface of the sixth lens on the light incident side and a curvature radius R12 of a surface of the sixth lens on the light exiting side satisfy: -3.5 < R11/R12 < -3.0. The ratio of the curvature radius of the surface of the sixth lens close to the light inlet side to the curvature radius of the surface of the sixth lens close to the light outlet side is restricted to be within a certain range, so that the coma aberration of an on-axis view field and an off-axis view field is small, and the imaging system has good imaging quality. Preferably, -3.45 < R11/R12 < -3.1.

In the present embodiment, the central thickness CT1 of the first lens on the optical axis and the edge thickness ET1 of the first lens satisfy: 2.5 < CT1/ET1 < 3.0. The ratio of the central thickness of the first lens on the optical axis and the edge thickness of the first lens is reasonably distributed, so that the lens assembly stability of the imaging system is improved, and the working stability of the imaging system is improved. Preferably, 2.8 < CT1/ET1 < 3.0.

In the present embodiment, the central thickness CT5 of the fifth lens on the optical axis and the edge thickness ET5 of the fifth lens satisfy: 2.0 < CT5/ET5 < 3.0. The ratio of the center thickness of the fifth lens on the optical axis to the edge thickness of the fifth lens is reasonably distributed, so that the sensitivity of the imaging system is favorably reduced, and the characteristics of large aperture and high resolution of the imaging system are favorably realized. Preferably, 2.2 < CT5/ET5 < 2.9.

In the present embodiment, the air interval T12 on the optical axis, the on-axis distance SAG12 between the intersection point of the surface of the first lens on the light exit side and the optical axis and the effective radius vertex of the surface of the first lens on the light exit side satisfy between the first lens and the second lens: 1.0 < T12/SAG12 < 2.0. The reasonable control first lens and second lens are at the epaxial air interval of light and the first lens are close to the surface of light-emitting side and the axial distance ratio on the axle between the nodical to the effective radius summit of the surface that first lens is close to the light-emitting side, and the size of visual field in the second lens incident angle can be controlled in being favorable to controlling the aberration of interior visual field, and then guarantee imaging system's imaging quality. Preferably, 1.2 < T12/SAG12 < 1.8.

In the present embodiment, the air interval T23 on the optical axis, the on-axis distance SAG22 between the intersection point of the surface of the second lens on the light exit side and the optical axis and the effective radius vertex of the surface of the second lens on the light exit side satisfy between the second lens and the third lens: 1.5 < T23/SAG22 < 2.6. Through restricting the air interval of second lens and third lens on the optical axis and the second lens be close to the surface of light-emitting side and the ratio of the axial distance between the intersect of optical axis to the effective radius summit of the surface of second lens near the light-emitting side in reasonable scope, can effectual control imaging system middle lens to the contribution degree of aberration, reduce imaging system's aberration, improve imaging quality. Preferably, 1.8 < T23/SAG22 < 2.6.

In the present embodiment, an on-axis distance SAG62 between an intersection point of a surface of the sixth lens on the light exit side and the optical axis to an effective radius apex of the surface of the sixth lens on the light exit side, and an air interval T56 of the fifth lens and the sixth lens on the optical axis satisfy: -2.0 < SAG62/T56 < -1.0. The ratio of the distance on the axis between the intersection point of the surface of the sixth lens close to the light-emitting side and the optical axis and the effective radius vertex of the surface of the sixth lens close to the light-emitting side to the air interval of the fifth lens and the sixth lens on the optical axis is in a certain range, so that the coma of the on-axis view field and the off-axis view field is small, and the imaging system has good imaging quality. Preferably, -1.8 < SAG62/T56 < -1.1.

In the present embodiment, the abbe number V2 of the second lens and the abbe number V3 of the third lens satisfy: V3-V2 < 20. The difference between the abbe number of the second lens and the abbe number of the third lens is restricted within a certain range, so that the chromatic aberration of the system is favorably improved, and the imaging quality of the imaging system is ensured.

In the present embodiment, the abbe number V3 of the third lens and the abbe number V4 of the fourth lens satisfy: V3-V4 < 15. By restricting the difference between the abbe number of the third lens and the abbe number of the fourth lens within a certain range, the material collocation of the imaging system can be controlled, which is beneficial to reducing the cost.

Example two

As shown in fig. 1 to 25, the imaging system sequentially includes, from the light incident side to the light exiting side of the imaging system: the diaphragm, the first lens with refractive power, the second lens with refractive power, the third lens with refractive power, the fourth lens with refractive power, the fifth lens with positive refractive power and the sixth lens with refractive power, wherein the surface of the first lens, close to the light incident side, is in a convex shape; the surface of the second lens close to the light incidence side is convex; the surface of the fourth lens close to the light incidence side is convex; the surface of the sixth lens close to the light incident side is concave; wherein, the air interval T12 on the optical axis, the axial distance SAG12 from the intersection point of the surface of the first lens close to the light-emitting side and the optical axis to the effective radius peak of the surface of the first lens close to the light-emitting side are satisfied between the first lens and the second lens: 1.0 < T12/SAG12 < 2.0.

By reasonably controlling the positive and negative distribution of the refractive power of each lens of the imaging system, the low-order aberration of the imaging system can be effectively balanced, the tolerance sensitivity of the imaging system can be reduced, the miniaturization of the imaging system is kept, and the imaging quality of the imaging system is ensured. The reasonable control first lens and second lens are at the epaxial air interval of light and the first lens are close to the surface of light-emitting side and the axial distance ratio on the axle between the nodical to the effective radius summit of the surface that first lens is close to the light-emitting side, and the size of visual field in the second lens incident angle can be controlled in being favorable to controlling the aberration of interior visual field, and then guarantee imaging system's imaging quality.

Preferably, the air interval T12 on the optical axis, the on-axis distance SAG12 from the intersection point of the surface of the first lens close to the light-emitting side and the optical axis to the effective radius vertex of the surface of the first lens close to the light-emitting side satisfy the following conditions: 1.2 < T12/SAG12 < 1.8.

In the present embodiment, the maximum field angle FOV of the imaging system satisfies: FOV > 80. The wide-field-of-view imaging system is large in field angle and wide in shooting field of view, so that the imaging system can clearly image a large range of shooting, and the wide-field-of-view imaging system has the advantage of being large in image plane. Preferably, the FOV is >87 °.

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 near the light incident side satisfy: 2.0 < f1/R1 < 2.5. The ratio of the effective focal length of the first lens to the curvature radius of the surface, close to the light incidence side, of the first lens is reasonably set, so that the processing sensitivity of the first lens is reduced while the performance of an imaging system is ensured. Preferably, 2.2 < f1/R1 < 2.4.

In the present embodiment, the effective focal length f1 of the first lens and the radius of curvature R2 of the surface of the first lens near the light exit side satisfy: r2/f1 is more than 1.5 and less than 2.0. By limiting R2/f1 within a reasonable range, the reasonable setting of the effective focal length of the first lens is facilitated, the overall focal length of the imaging system is increased, and the imaging system has a large image plane. Preferably, 1.55 < R2/f1 < 1.8.

In the present embodiment, the effective focal length f2 of the second lens and the radius of curvature R4 of the surface of the second lens near the light exit side satisfy: -3.5 < f2/R4 < -2.0. By limiting f2/R4 within a reasonable range, the effective focal length of the second lens is reasonably set, the light ray position is favorably adjusted, the total length of the imaging system is shortened, and the miniaturization of the imaging system is facilitated. Preferably, -3.3 < f2/R4 < -2.3.

In the present embodiment, a curvature radius R7 of a surface of the fourth lens on the light incident side and a curvature radius R8 of a surface of the fourth lens on the light exit side satisfy: R7/R8 is more than or equal to 1.0 and less than or equal to 1.6. By limiting R7/R8 within a reasonable range, the incidence angle of the off-axis field rays on an imaging surface is favorably controlled, and the matching with the photosensitive element and the band-pass filter is increased. Preferably, 1.0. ltoreq.R 7/R8 < 1.55.

In the present embodiment, an effective focal length f5 of the fifth lens and a radius of curvature R10 of a surface of the fifth lens on the light exit side satisfy: -2.0 < f5/R10 < -1.0. The ratio of the effective focal length of the fifth lens to the curvature radius of the surface of the fifth lens close to the light-emitting side is restricted to be within a certain range, so that the imaging system is favorable for having good imaging quality. Preferably, -1.9 < f5/R10 < -1.1.

In the present embodiment, a curvature radius R11 of a surface of the sixth lens on the light incident side and a curvature radius R12 of a surface of the sixth lens on the light exit side satisfy: -3.5 < R11/R12 < -3.0. The ratio of the curvature radius of the surface of the sixth lens close to the light inlet side to the curvature radius of the surface of the sixth lens close to the light outlet side is restricted to be within a certain range, so that the coma aberration of an on-axis view field and an off-axis view field is small, and the imaging system has good imaging quality. Preferably, -3.45 < R11/R12 < -3.1.

In the present embodiment, the air interval T23 on the optical axis, the on-axis distance SAG22 between the intersection point of the surface of the second lens on the light exit side and the optical axis and the effective radius vertex of the surface of the second lens on the light exit side satisfy between the second lens and the third lens: 1.5 < T23/SAG22 < 2.6. The ratio of the air interval of the second lens and the third lens on the optical axis to the axial distance between the intersection point of the surface of the second lens close to the light-emitting side and the optical axis and the effective radius vertex of the surface of the second lens close to the light-emitting side is restricted within a reasonable range, so that the contribution degree of the middle lens of the imaging system to the aberration can be effectively controlled, the aberration of the imaging system is reduced, and the imaging quality is improved. Preferably, 1.8 < T23/SAG22 < 2.6.

In the present embodiment, an on-axis distance SAG62 between an intersection point of a surface of the sixth lens on the light exit side and the optical axis to an effective radius apex of the surface of the sixth lens on the light exit side, and an air interval T56 of the fifth lens and the sixth lens on the optical axis satisfy: -2.0 < SAG62/T56 < -1.0. The ratio of the distance on the axis between the effective radius vertex of the surface close to the light-emitting side of the sixth lens and the effective radius vertex of the surface close to the light-emitting side of the sixth lens to the air interval of the fifth lens and the sixth lens on the optical axis is in a certain range, so that the coma of the on-axis visual field and the off-axis visual field is small, and the imaging system has good imaging quality. Preferably, -1.8 < SAG62/T56 < -1.1.

The imaging system in the present application may employ a plurality of lenses, such as the six lenses described above. By reasonably distributing the refractive power, the surface shape, the central thickness of each lens, the on-axis distance between each lens and the like, the aperture of the imaging system can be effectively increased, the sensitivity of the lens can be reduced, and the machinability of the lens can be improved, so that the imaging system is more beneficial to production and processing and can be suitable for portable electronic equipment such as smart phones.

In the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The aspheric lens is characterized in 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 center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics, 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 will be appreciated by those skilled in the art that the number of lenses making up the imaging system can be varied to achieve the various results and advantages described in this specification without departing from the claimed subject matter. For example, although six lenses are exemplified in the embodiment, the imaging system is not limited to including six lenses. The imaging system may also include other numbers of lenses, as desired.

Examples of specific surface types, parameters applicable to the imaging system of the above embodiment are further described below with reference to the drawings.

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

Example one

As shown in fig. 1 to 5, an imaging system of example one of the present application is described. Fig. 1 shows a schematic diagram of the configuration of an imaging system of example one.

As shown in fig. 1, the imaging system sequentially includes, from the light incident side to the light emergent side: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, filter E7, and image plane S15.

The first lens element E1 with positive refractive power has a convex surface S1 on the light incident side and a concave surface S2 on the light emergent side. The second lens element E2 with negative refractive power has a convex surface S3 on the light incident side and a concave surface S4 on the light emergent side. The third lens element E3 with positive refractive power has a convex surface S5 on the light incident side and a convex surface S6 on the light emergent side. The fourth lens element E4 with negative refractive power has a convex surface S7 on the light incident side and a concave surface S8 on the light emergent side. The fifth lens element E5 with positive refractive power has a convex surface S9 on the light incident side and a convex surface S10 on the light emergent side. The sixth lens element E6 with negative refractive power has a concave surface S11 on the light incident side and a concave surface S12 on the light emergent side. The filter E7 has an entrance side S13 and an exit side S14. The light from the object passes through the respective surfaces S1 to S14 in order and is finally imaged on the imaging surface S15.

In this example, the total effective focal length f of the imaging system is 5.07mm, the total length TTL of the imaging system is 5.95mm, and the image height ImgH is 5.04 mm.

Table 1 shows a basic structural parameter table of the imaging system of example one, in which the units of the radius of curvature, the thickness/distance, the focal length, and the effective radius are millimeters (mm).

TABLE 1

In the first example, the surface of any one of the first lens E1 to the sixth lens E6 close to the light incident side and the light emergent side are both aspheric surfaces, and the surface shape of each aspheric lens can be defined by, but is not limited to, the following aspheric surface formula:

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 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 A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, A30 that can be used for each of the aspherical mirrors S1-S12 in example one.

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

1.2430E-02

4.7575E-04

-1.1130E-03

-5.1401E-04

-2.2956E-04

-4.8923E-05

-2.9277E-05

S2

-4.1795E-02

6.1072E-03

-1.9661E-03

2.1588E-04

3.4558E-06

-4.8467E-05

-2.6103E-05

S3

-1.7675E-02

1.6470E-02

-1.2888E-03

1.0064E-03

2.6742E-05

-4.0112E-05

-4.0198E-05

S4

2.3486E-02

1.1122E-02

5.2728E-04

9.8037E-04

2.8178E-04

1.1459E-04

3.6236E-05

S5

-8.6773E-02

-5.5541E-03

-5.5155E-04

4.2660E-04

2.1116E-04

1.2069E-04

3.6936E-05

S6

-1.7727E-01

-8.5135E-04

2.6436E-03

3.6255E-03

1.2947E-03

6.8415E-04

2.0185E-04

S7

-6.3646E-01

2.8986E-02

-1.3979E-02

4.1516E-03

1.3394E-03

1.5805E-03

6.0494E-04

S8

-9.2444E-01

1.6919E-01

-2.3920E-02

1.4157E-03

-2.1301E-03

1.4197E-03

-1.7201E-04

S9

-1.4429E+00

1.8395E-01

1.0122E-01

-4.5402E-02

-2.1058E-02

2.1372E-02

-9.4704E-05

S10

1.0131E+00

-4.1576E-01

1.2047E-01

1.9090E-02

-2.5156E-02

1.2039E-02

-4.2065E-03

S11

3.1447E-01

5.5855E-01

-3.4703E-01

2.2988E-01

-1.4708E-01

7.0265E-02

-2.1694E-02

S12

-5.8814E+00

1.4467E+00

-3.1201E-01

1.8518E-01

-1.1158E-01

3.7895E-02

-3.1798E-02

Flour mark

A18

A20

A22

A24

A26

A28

A30

S1

-5.0236E-06

-1.2552E-05

-6.5623E-06

-4.9933E-06

-1.9212E-06

-1.0640E-06

1.5008E-06

S2

-2.8452E-05

-1.0252E-05

-1.1460E-05

-3.2423E-06

1.9201E-07

5.8258E-06

-1.3762E-06

S3

-2.5991E-05

-1.9495E-05

-1.1098E-05

-1.1462E-05

-1.5715E-06

3.3608E-06

5.9817E-06

S4

1.3953E-05

-3.3378E-06

-4.4220E-06

-8.7909E-06

-4.6760E-06

-2.3817E-06

1.9687E-06

S5

1.5976E-05

4.6470E-06

1.2267E-06

-8.8294E-07

4.1722E-07

1.9312E-06

-1.0048E-06

S6

9.4083E-05

1.2013E-05

3.1548E-06

-6.6915E-06

-3.3147E-06

-4.7066E-06

-6.2628E-07

S7

3.0783E-04

9.0148E-05

-1.6199E-05

-3.7168E-05

-3.2301E-05

-2.0437E-05

-9.1833E-06

S8

3.1582E-05

-4.4034E-05

-6.6235E-06

1.3929E-05

1.3401E-06

-1.0863E-06

-3.4844E-06

S9

-5.3843E-03

1.1226E-03

8.8278E-04

-3.4152E-04

-1.8131E-04

1.7658E-04

-4.5618E-05

S10

2.4221E-03

3.3668E-03

-2.2019E-03

-4.3424E-04

2.0029E-04

1.1226E-05

-4.5950E-05

S11

4.9849E-03

-4.9855E-03

5.0857E-03

-3.5360E-03

1.0677E-03

-1.0290E-04

-1.6449E-05

S12

1.7882E-02

-2.1157E-03

4.3825E-03

-5.2766E-03

-2.5580E-04

-3.3122E-04

9.5968E-04

TABLE 2

Fig. 2 shows an on-axis chromatic aberration curve of the imaging system of example one, which represents the deviation of the convergent focus of light rays of different wavelengths after passing through the imaging system. Fig. 3 shows astigmatism curves of the imaging system of example one, which represent meridional field curvature and sagittal field curvature. Fig. 4 shows distortion curves of the imaging system of example one, which represent distortion magnitude values corresponding to different angles of view. Fig. 5 shows a chromatic aberration of magnification curve of the imaging system of example one, which represents the deviation of different image heights on the imaging plane after the light passes through the imaging system.

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

Example two

As shown in fig. 6 to 10, an imaging system of example two of the present application is described. In this example and the following examples, descriptions of parts similar to example one will be omitted for the sake of brevity. Fig. 6 shows a schematic diagram of the configuration of the imaging system of example two.

As shown in fig. 6, the imaging system sequentially includes, from the light incident side to the light emergent side: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, filter E7, and image plane S15.

The first lens element E1 with positive refractive power has a convex surface S1 on the light incident side and a concave surface S2 on the light emergent side. The second lens element E2 with negative refractive power has a convex surface S3 on the light incident side and a concave surface S4 on the light emergent side. The third lens element E3 with positive refractive power has a concave surface S5 on the light incident side and a convex surface S6 on the light emergent side. The fourth lens element E4 with negative refractive power has a convex surface S7 on the light incident side and a concave surface S8 on the light emergent side. The fifth lens element E5 with positive refractive power has a convex surface S9 on the light incident side and a convex surface S10 on the light emergent side. The sixth lens element E6 with negative refractive power has a concave surface S11 on the light incident side and a concave surface S12 on the light emergent side. The filter E7 has an entrance side S13 of the filter and an exit side S14 of the filter. The light from the object passes through the respective surfaces S1 to S14 in order and is finally imaged on the imaging surface S15.

Table 3 shows a basic structural parameter table of the imaging system of example two, in which 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

3.7501E-03

-3.0900E-03

-2.3703E-03

-9.1108E-04

-3.1251E-04

-6.3236E-05

-2.0520E-05

S2

-5.4645E-02

4.8676E-03

-2.3748E-03

1.3687E-04

-5.3766E-05

-8.0017E-05

-3.0353E-05

S3

-1.5152E-02

1.7790E-02

-1.2746E-03

1.0871E-03

-2.7216E-05

-3.6977E-05

-3.7877E-05

S4

2.0956E-02

1.0080E-02

3.5671E-04

8.4254E-04

2.6690E-04

8.9022E-05

4.6381E-05

S5

-7.7187E-02

-4.2594E-03

6.3489E-04

6.5010E-04

4.2889E-04

1.1400E-04

7.7387E-05

S6

-1.5035E-01

2.8765E-03

4.0758E-03

3.1014E-03

1.0917E-03

4.5927E-04

1.6041E-04

S7

-6.4140E-01

1.2319E-02

-1.4558E-02

1.0303E-02

3.1713E-03

1.6668E-03

9.2225E-05

S8

-1.0218E+00

1.6725E-01

-3.6127E-02

1.3470E-02

-3.9394E-03

6.5212E-04

-2.1884E-04

S9

-1.2005E+00

8.0625E-02

9.1418E-02

-1.7882E-02

-2.1965E-02

8.2560E-03

4.7295E-03

S10

9.0973E-01

-3.8142E-01

1.2024E-01

8.5692E-03

-2.0584E-02

3.5710E-03

-3.2258E-06

S11

1.6906E-01

5.2365E-01

-3.1763E-01

1.9401E-01

-1.1417E-01

5.1112E-02

-1.4219E-02

S12

-5.5991E+00

1.3309E+00

-3.0240E-01

1.6454E-01

-8.7569E-02

3.0052E-02

-2.6865E-02

Flour mark

A18

A20

A22

A24

A26

A28

A30

S1

-4.1802E-06

-9.1038E-06

-4.2601E-06

7.9114E-07

3.3644E-06

2.7977E-06

2.5530E-06

S2

-1.5863E-05

1.7529E-06

3.4175E-06

5.3167E-06

5.2690E-06

4.5596E-06

-1.3568E-06

S3

-6.9345E-06

-1.0317E-05

1.3491E-06

-8.9015E-06

2.1603E-06

3.9209E-06

9.2411E-06

S4

1.0522E-05

6.5810E-06

2.3012E-06

4.0330E-06

1.1695E-06

-2.2725E-06

-6.8025E-06

S5

1.1284E-06

1.9778E-05

-6.2691E-06

5.4806E-06

-4.5211E-06

2.7025E-06

-1.7139E-06

S6

4.6339E-05

2.1091E-05

-3.5137E-06

2.4064E-06

-9.2750E-06

-1.9587E-06

-7.1422E-06

S7

-1.1330E-04

-2.1744E-04

-8.9115E-05

-5.0049E-05

4.0069E-06

-1.3294E-06

3.4964E-08

S8

2.1981E-04

-9.2094E-05

2.9665E-05

-2.1966E-05

3.5878E-06

-1.1641E-05

4.6627E-06

S9

-2.0854E-03

-7.4461E-04

1.4324E-04

2.0173E-04

-1.3301E-05

4.0139E-05

-3.5320E-05

S10

1.5404E-03

2.1708E-03

-6.9908E-04

-4.1641E-04

8.5510E-05

6.2887E-05

-6.8036E-07

S11

4.7179E-04

-1.1646E-03

2.6994E-03

-2.7114E-03

1.2766E-03

-3.6341E-04

1.3569E-06

S12

1.2495E-02

-2.3549E-03

3.5857E-03

-3.8044E-03

-9.7799E-05

-1.7382E-04

6.4720E-04

TABLE 4

Fig. 7 shows an on-axis chromatic aberration curve of the imaging system of example two, which represents the deviation of the convergent focus of light rays of different wavelengths after passing through the imaging system. Fig. 8 shows astigmatism curves of the imaging system of example two, which represent meridional field curvature and sagittal field curvature. Fig. 9 shows distortion curves of the imaging system of example two, which represent distortion magnitude values corresponding to different angles of view. Fig. 10 shows a chromatic aberration of magnification curve of the imaging system of example two, which represents the deviation of different image heights on the imaging plane after the light passes through the imaging system.

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

EXAMPLE III

As shown in fig. 11 to 15, an imaging system of example three of the present application is described. Fig. 11 shows a schematic diagram of the configuration of an imaging system of example three.

As shown in fig. 11, the imaging system sequentially includes, from the light incident side to the light emergent side: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, filter E7, and image plane S15.

The first lens element E1 with positive refractive power has a convex surface S1 on the light incident side and a concave surface S2 on the light emergent side. The second lens element E2 with negative refractive power has a convex surface S3 on the light incident side and a concave surface S4 on the light emergent side. The third lens element E3 with negative refractive power has a concave surface S5 on the light incident side and a convex surface S6 on the light emergent side. The fourth lens element E4 with negative refractive power has a convex surface S7 on the light incident side and a concave surface S8 on the light emergent side. The fifth lens element E5 with positive refractive power has a convex surface S9 on the light incident side and a convex surface S10 on the light emergent side. The sixth lens element E6 with negative refractive power has a concave surface S11 on the light incident side and a concave surface S12 on the light emergent side. The filter E7 has an entrance side S13 and an exit side S14. The light from the object passes through the respective surfaces S1 to S14 in order and is finally imaged on the imaging surface S15.

In this example, the total effective focal length f of the imaging system is 5.06mm, the total length TTL of the imaging system is 5.95mm, and the image height ImgH is 5.04 mm.

Table 5 shows a basic structural parameter table of the imaging system of example three, in which the units of the radius of curvature, thickness/distance, focal length, and 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.

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

2.6483E-03

-3.1226E-03

-2.9651E-03

-9.4259E-04

-4.0081E-04

-1.2678E-05

-3.9833E-05

S2

-5.7153E-02

4.6478E-03

-2.0377E-03

9.2690E-05

-7.2131E-06

-1.1937E-04

-1.8479E-05

S3

-1.2652E-02

1.8080E-02

-5.8632E-04

1.0682E-03

-1.5397E-05

-5.1528E-05

-5.2315E-05

S4

2.8217E-02

1.0658E-02

8.3722E-04

7.3373E-04

1.9453E-04

2.2131E-05

1.4838E-05

S5

-8.5973E-02

-4.3141E-03

9.1368E-04

5.2596E-04

3.8645E-04

2.7367E-05

6.0287E-05

S6

-1.7432E-01

8.9871E-03

4.3356E-03

4.0937E-03

9.9242E-04

5.5853E-04

5.2219E-05

S7

-7.2654E-01

1.1320E-02

-1.1155E-02

1.5018E-02

5.0700E-03

1.8789E-03

-6.7092E-04

S8

-1.0192E+00

1.6230E-01

-3.3039E-02

1.1984E-02

-3.0801E-03

5.4260E-04

-3.7730E-04

S9

-1.1695E+00

7.1362E-02

8.4588E-02

-1.5895E-02

-1.9050E-02

7.3183E-03

3.4602E-03

S10

8.5388E-01

-3.5398E-01

9.6318E-02

1.5942E-02

-1.7891E-02

1.9486E-03

-1.5581E-03

S11

2.0349E-01

5.2435E-01

-3.2343E-01

1.9696E-01

-1.1835E-01

5.4436E-02

-1.6437E-02

S12

-5.7982E+00

1.3936E+00

-3.2401E-01

1.6009E-01

-9.3144E-02

3.0424E-02

-2.7624E-02

Flour mark

A18

A20

A22

A24

A26

A28

A30

S1

2.2504E-05

-1.4418E-05

9.4609E-06

-3.8402E-06

6.8371E-06

-2.9154E-06

5.4506E-06

S2

-2.1733E-05

1.9080E-05

1.2728E-06

1.0215E-05

1.7052E-08

5.6669E-06

-7.0389E-06

S3

-4.0024E-06

-1.0714E-05

5.5228E-06

-6.7287E-06

6.7164E-06

2.5684E-06

9.5880E-06

S4

-1.1075E-05

1.0025E-06

-3.3631E-06

1.0404E-06

-4.7507E-06

-1.1064E-06

-1.7077E-06

S5

-2.6844E-05

2.1367E-05

-1.6037E-05

1.0151E-05

-6.3465E-06

7.5053E-06

-3.2876E-06

S6

5.1025E-05

-2.6494E-05

-5.5985E-07

-1.9609E-05

-5.0308E-06

-1.2065E-05

-2.4548E-06

S7

-7.1269E-04

-5.4795E-04

-1.3548E-04

-2.4378E-06

7.2437E-05

4.5498E-05

2.3527E-05

S8

3.7683E-04

-1.1842E-04

2.1342E-05

-4.7025E-05

1.1035E-05

-9.1152E-06

4.2395E-06

S9

-9.5889E-04

-7.4614E-04

-7.3577E-06

8.1324E-05

6.9443E-05

1.8866E-05

-3.3374E-05

S10

9.4280E-04

1.9853E-03

-8.7582E-05

-3.5234E-04

3.1870E-05

1.6915E-05

4.5259E-06

S11

1.1824E-03

-6.1267E-04

1.9931E-03

-2.6022E-03

1.4802E-03

-6.1538E-04

1.0625E-04

S12

1.3384E-02

-1.8402E-03

3.1390E-03

-4.3921E-03

4.7432E-05

-1.4126E-04

6.3158E-04

TABLE 6

Fig. 12 shows an on-axis chromatic aberration curve of the imaging system of example three, which represents the convergent focus deviation of light rays of different wavelengths after passing through the imaging system. Fig. 13 shows astigmatism curves of the imaging system of example three, which represent meridional field curvature and sagittal field curvature. Fig. 14 shows distortion curves of the imaging system of example three, which represent distortion magnitude values corresponding to different angles of view. Fig. 15 shows a chromatic aberration of magnification curve of the imaging system of example three, which represents the deviation of different image heights on the imaging plane after the light passes through the imaging system.

As can be seen from fig. 12 to 15, the imaging system given in example three can achieve good imaging quality.

Example four

As shown in fig. 16 to 20, an imaging system of example four of the present application is described. Fig. 16 shows a schematic diagram of the imaging system configuration of example four.

As shown in fig. 16, the image forming system sequentially comprises from the light incident side to the light emergent side: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, filter E7, and image plane S15.

The first lens element E1 with positive refractive power has a convex surface S1 on the light incident side and a concave surface S2 on the light emergent side. The second lens element E2 with negative refractive power has a convex surface S3 on the light incident side and a concave surface S4 on the light emergent side. The third lens element E3 with negative refractive power has a concave surface S5 on the light incident side and a concave surface S6 on the light emergent side. The fourth lens element E4 with negative refractive power has a convex surface S7 on the light incident side and a concave surface S8 on the light emergent side. The fifth lens element E5 with positive refractive power has a convex surface S9 on the light incident side and a convex surface S10 on the light emergent side. The sixth lens element E6 with negative refractive power has a concave surface S11 on the light incident side and a concave surface S12 on the light emergent side. The filter E7 has an entrance side S13 and an exit side S14. The light from the object passes through the respective surfaces S1 to S14 in order and is finally imaged on the imaging surface S15.

Table 7 shows a basic structural parameter table of the imaging system of example four, in which the units of the radius of curvature, thickness/distance, focal length, and effective radius are millimeters (mm).

TABLE 7

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

TABLE 8

Fig. 17 shows an on-axis chromatic aberration curve of the imaging system of example four, which represents the convergent focus deviation of light rays of different wavelengths after passing through the imaging system. Fig. 18 shows astigmatism curves of the imaging system of example four, which represent meridional field curvature and sagittal field curvature. Fig. 19 shows distortion curves of the imaging system of example four, which represent distortion magnitude values corresponding to different angles of view. Fig. 20 shows a chromatic aberration of magnification curve of the imaging system of example four, which represents the deviation of different image heights on the imaging plane after the light passes through the imaging system.

As can be seen from fig. 17 to 20, the imaging system given in example four can achieve good imaging quality.

Example five

As shown in fig. 21 to 25, an imaging system of example five of the present application is described. Fig. 21 shows a schematic diagram of the imaging system configuration of example five.

As shown in fig. 21, the imaging system sequentially comprises from the light incident side to the light emergent side: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, filter E7, and image plane S15.

The first lens element E1 with positive refractive power has a convex surface S1 on the light incident side and a concave surface S2 on the light emergent side. The second lens element E2 with negative refractive power has a convex surface S3 on the light incident side and a concave surface S4 on the light emergent side. The third lens element E3 with positive refractive power has a concave surface S5 on the light incident side and a convex surface S6 on the light emergent side. The fourth lens element E4 with negative refractive power has a convex surface S7 on the light incident side and a concave surface S8 on the light emergent side. The fifth lens element E5 with positive refractive power has a concave surface S9 on the light incident side and a convex surface S10 on the light emergent side. The sixth lens element E6 with negative refractive power has a concave surface S11 on the light incident side and a concave surface S12 on the light emergent side. The filter E7 has an entrance side S13 and an exit side S14. The light from the object passes through the respective surfaces S1 to S14 in order and is finally imaged on the imaging surface S15.

Table 9 shows a basic structural parameter table of the imaging system of example five, in which the units of the radius of curvature, thickness/distance, focal length, and effective radius are all 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.

Watch 10

Fig. 22 shows an on-axis chromatic aberration curve of the imaging system of example five, which represents the convergent focus deviation of light rays of different wavelengths after passing through the imaging system. Fig. 23 shows astigmatism curves of the imaging system of example five, which represent meridional field curvature and sagittal field curvature. Fig. 24 shows distortion curves of the imaging system of example five, which represent distortion magnitude values corresponding to different angles of view. Fig. 25 shows a chromatic aberration of magnification curve of the imaging system of example five, which represents the deviation of different image heights on the imaging plane after the light passes through the imaging system.

As can be seen from fig. 12 to 25, the imaging system given in example five can achieve good imaging quality.

To sum up, examples one to five respectively satisfy the relationships shown in table 11.

Conditions/examples	1	2	3	4	5
						f/EPD	1.88	1.90	1.90	1.90	1.90
FOV	88.1	87.8	87.8	87.7	87.7
						TTL/ImgH	1.18	1.18	1.18	1.18	1.18
f1/R1	2.37	2.36	2.38	2.36	2.34
						R2/f1	1.61	1.64	1.57	1.61	1.71
f2/R4	-2.74	-2.39	-2.73	-2.57	-3.14
						R7/R8	1.27	1.51	1.22	1.23	1.04
f5/R10	-1.21	-1.17	-1.19	-1.18	-1.88
						f/f6	-1.68	-1.61	-1.62	-1.62	-1.70
R11/R12	-3.29	-3.31	-3.19	-3.28	-3.42
						CT1/ET1	2.89	2.92	2.95	2.94	2.86
CT5/ET5	2.72	2.73	2.85	2.76	2.47
						T12/SAG12	1.28	1.66	1.34	1.44	1.26
T23/SAG22	2.04	2.11	2.46	2.59	1.93
						(SAG51+SAG52)/(SAG51-SAG52)	-2.67	-2.20	-2.29	-2.26	-3.77
SAG62/T56	-1.35	-1.41	-1.55	-1.52	-1.18

TABLE 11

Table 12 gives the effective focal lengths f of the imaging systems of examples one to five, and the effective focal lengths f1 to f6 of the respective lenses.

TABLE 12

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 apparatus is equipped with the imaging system 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 imaging system, comprising in order along a light-in side of the imaging system to a light-out side of the imaging system:

a diaphragm;

the surface of the first lens, which is close to the light incidence side, is in a convex shape;

the surface of the second lens, which is close to the light incidence side, is in a convex shape;

a third lens element with refractive power;

The surface, close to the light inlet side, of the fourth lens is in a convex shape;

a fifth lens element with positive refractive power;

the surface, close to the light incidence side, of the sixth lens is concave;

an on-axis distance SAG51 from the intersection point of the surface of the fifth lens close to the light inlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light inlet side, and an on-axis distance SAG52 from the intersection point of the surface of the fifth lens close to the light outlet side and the optical axis to the effective radius vertex of the surface of the fifth lens close to the light outlet side satisfy the following conditions: -4.5 < (SAG51+ SAG52)/(SAG51-SAG52) < -2.0.

2. The imaging system of claim 1, wherein a maximum field angle FOV of the imaging system satisfies: FOV > 80.

3. The imaging system of claim 1, wherein an effective focal length f of the imaging system and an entrance pupil diameter EPD of the imaging system satisfy: f/EPD is less than or equal to 1.9.

4. The imaging system of claim 1, wherein an on-axis distance TTL from a surface of the first lens closer to a light entrance side to an imaging plane of the imaging system and a half ImgH of a diagonal length of an effective pixel area on the imaging plane satisfy: TTL/ImgH is less than 1.2.

5. The imaging system of claim 1, wherein an effective focal length f1 of the first lens and a radius of curvature R1 of a surface of the first lens near the light entrance side satisfy: 2.0 < f1/R1 < 2.5.

6. The imaging system of claim 1, wherein an effective focal length f1 of the first lens and a radius of curvature R2 of a surface of the first lens near the light exit side satisfy: r2/f1 is more than 1.5 and less than 2.0.

7. The imaging system of claim 1, wherein an effective focal length f2 of the second lens and a radius of curvature R4 of a surface of the second lens near the light exit side satisfy: -3.5 < f2/R4 < -2.0.

8. The imaging system of claim 1, wherein a radius of curvature R7 of a surface of the fourth lens near the light-in side and a radius of curvature R8 of a surface of the fourth lens near the light-out side satisfy: R7/R8 is more than or equal to 1.0 and less than or equal to 1.6.

9. The imaging system of claim 1, wherein an effective focal length f5 of the fifth lens and a radius of curvature R10 of a surface of the fifth lens near the light exit side satisfy: -2.0 < f5/R10 < -1.0.

10. An imaging system, comprising in sequence from an entrance side of the imaging system to an exit side of the imaging system:

A diaphragm;

the surface of the first lens, which is close to the light inlet side, is in a convex shape;

a third lens element with refractive power;

the surface of the fourth lens, which is close to the light incidence side, is in a convex shape;

a fifth lens element with positive refractive power;

the surface, close to the light inlet side, of the sixth lens is concave;

wherein, the air interval T12 of the first lens and the second lens on the optical axis of the imaging system, the on-axis distance SAG12 from the intersection point of the surface of the first lens close to the light-emitting side and the optical axis to the effective radius vertex of the surface of the first lens close to the light-emitting side satisfy the following conditions: 1.0 < T12/SAG12 < 2.0.