CN114442279A

CN114442279A - Imaging system

Info

Publication number: CN114442279A
Application number: CN202210134132.8A
Authority: CN
Inventors: 杨泉锋; 贺凌波; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2022-02-14
Filing date: 2022-02-14
Publication date: 2022-05-06
Anticipated expiration: 2042-02-14
Also published as: CN114442279B

Abstract

The invention provides an imaging system, which comprises the following components from the light inlet side of the imaging system to the light outlet side of the imaging system: the surface of the first lens, which is close to the light incidence side, is a concave surface; a second lens having an optical power; the surface of the third lens, which is close to the light-emitting side, is a convex surface; a fourth lens having a negative optical power, the fourth lens having an Abbe number less than 20; a fifth lens having a focal power; a sixth lens having optical power; wherein the maximum field angle FOV of the imaging system satisfies: FOV > 120. The invention solves the problem that the imaging system in the prior art is difficult to miniaturize.

Description

Imaging system

Technical Field

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

Background

Along with the rapid development of electronic products such as smart phones and tablet computers, the demand of portable electronic products for lenses is increasing, the quality requirements of people for lens imaging are also increasing, and the development of portable electronic products towards miniaturization is continuously promoted by the trend. In order to meet the market demand, the lens needs to be as thin and small as possible, and the design difficulty increases. Meanwhile, as the performance of the image sensor is improved and the size of the image sensor is reduced, the design freedom of the corresponding lens is smaller and smaller, and the design difficulty is increased day by day.

That is, the related art imaging system has a problem that it is difficult to miniaturize.

Disclosure of Invention

The invention mainly aims to provide an imaging system to solve the problem that the imaging system in the prior art is difficult to miniaturize.

In order to achieve the above object, according to one aspect of the present invention, there is provided an imaging system comprising, from an entrance side of the imaging system to an exit side of the imaging system: the surface of the first lens, which is close to the light incidence side, is a concave surface; a second lens having an optical power; the surface of the third lens, which is close to the light-emitting side, is a convex surface; a fourth lens having a negative optical power, the fourth lens having an Abbe number less than 20; a fifth lens having optical power; a sixth lens having optical power; wherein the maximum field angle FOV of the imaging system satisfies: FOV > 120.

Further, the effective focal length f of the imaging system and the entrance pupil diameter EPD of the imaging system satisfy: f/EPD < 2.3.

Further, the effective focal length f2 of the second lens and the effective focal length f5 of the fifth lens satisfy: f2/f5 is more than 1.0 and less than 2.5.

Further, the curvature radius R3 of the surface of the second lens close to the light inlet side and the curvature radius R11 of the surface of the sixth lens close to the light inlet side satisfy that: 2.0 < R3/R11 < 5.0.

Further, the curvature radius R9 of the surface of the fifth 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: 1.5 < R9/R12 < 2.6.

Further, the curvature radius R3 of the surface of the second 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: 2.0 < R3/R12 < 5.0.

Further, the central thickness CT1 of the first lens on the optical axis and the central thickness CT2 of the second lens on the optical axis satisfy: 1.5 < CT2/CT1 < 4.0.

Further, a center thickness CT3 of the third lens on the optical axis and an air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 2.0 < CT3/T34 < 3.0.

Further, a central thickness CT4 of the fourth lens on the optical axis and a central thickness CT6 of the sixth lens on the optical axis satisfy: CT6/CT4 is more than or equal to 1.5 and less than 2.0.

Further, an on-axis distance SAG11 from the intersection point of the surface of the first lens close to the light inlet side and the optical axis to the effective radius vertex of the surface of the first lens close to the light inlet side, and an on-axis distance SAG12 from the intersection point of the surface of the first lens close to the light outlet side and the optical axis to the effective radius vertex of the surface of the first lens close to the light outlet side satisfy: 1.0 < SAG12/SAG11 < 3.0.

Further, an on-axis distance SAG52 between an intersection point of a surface of the fifth lens close to the light-emitting side and the optical axis and an effective radius vertex of a surface of the fifth lens close to the light-emitting side, and an on-axis distance SAG61 between an intersection point of a surface of the sixth lens close to the light-entering side and the optical axis and an effective radius vertex of a surface of the sixth lens close to the light-entering side satisfy: 0.5 < SAG61/SAG52 < 2.5.

Further, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the imaging system satisfy that: -4.0 < f12/f < -2.5.

Further, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the imaging system satisfy that: f34/f is more than 3.0 and less than 5.0.

Further, the combined focal length f456 of the fourth lens, the fifth lens and the sixth lens and the effective focal length f of the imaging system satisfy: f456/f is more than 3.0 and less than 5.5.

Further, the abbe number V2 of the second lens satisfies: v2 < 25.

According to another aspect of the present invention, there is provided an imaging system, comprising from a light-in side of the imaging system to a light-out side of the imaging system: the surface of the first lens, which is close to the light incidence side, is a concave surface; a second lens having an optical power; the surface of the third lens, which is close to the light-emitting side, is a convex surface; a fourth lens having a negative optical power, the fourth lens having an Abbe number less than 20; a fifth lens having optical power; a sixth lens having a focal power; wherein, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the imaging system satisfy the following conditions: -4.0 < f12/f < -2.5.

Further, the abbe number V2 of the second lens satisfies: v2 < 25.

By applying the technical scheme of the invention, the device comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from the light-in side of the imaging system to the light-out side of the imaging system. The first lens has negative focal power, and the surface of the first lens close to the light incident side is a concave surface; the second lens has focal power; the third lens has focal power, and the surface of the third lens close to the light-emitting side is a convex surface; the fourth lens has negative focal power, and the Abbe number of the fourth lens is less than 20; the fifth lens has focal power; the sixth lens has focal power; wherein the maximum field angle FOV of the imaging system satisfies: FOV > 120.

By reasonably controlling the positive and negative distribution of the focal 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. By limiting the FOV within a reasonable range, the imaging system can still have a good imaging range under the condition of a certain volume, and the requirement of a wide-angle lens is met. That is to say, the imaging system still has better imaging effect while satisfying the miniaturization.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiment(s) 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. 2-4 illustrate on-axis, astigmatic, and chromatic magnification difference curves, respectively, for the imaging system of FIG. 1;

fig. 5 is a schematic configuration diagram showing an imaging system of example two of the present invention;

6-8 show on-axis, astigmatic, and magnification chromatic aberration curves, respectively, for the imaging system of FIG. 5;

fig. 9 is a schematic configuration diagram showing an imaging system of example three of the present invention;

10-12 show on-axis, astigmatic, and chromatic magnification difference curves, respectively, for the imaging system of FIG. 9;

fig. 13 is a schematic configuration diagram showing an imaging system of example four of the present invention;

fig. 14 to 16 show an on-axis chromatic aberration curve, an astigmatism curve, and a chromatic aberration of magnification curve, respectively, of the imaging system in fig. 13;

fig. 17 is a schematic structural view showing an imaging system of example five of the present invention;

fig. 18 to 20 show an on-axis chromatic aberration curve, an astigmatism curve, and a chromatic aberration of magnification curve, respectively, of the imaging system in fig. 17;

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

fig. 22 to 24 show an on-axis chromatic aberration curve, an astigmatism curve, and a chromatic aberration of magnification curve, respectively, of the imaging system in fig. 21.

Wherein the figures include the following reference numerals:

e1, first lens; s1, the surface of the first lens close to the light incident 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 second lens is close to the surface of the light-emitting side; STO, stop; 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 emergent side; e6, sixth lens; s11, the surface of the sixth lens, which is 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 surface of the filter plate close to the light incident side; s14, the surface of the filter plate close to the light emergent side; and S15, imaging surface.

Detailed Description

It should be noted that, in the present application, the embodiments and features of the embodiments 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 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. Regarding the surface close to the light 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 light exit 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 imaging system, aiming at solving the problem that the imaging system in the prior art is difficult to miniaturize.

Example one

As shown in fig. 1 to 24, the lens from the light-in side of the imaging system to the light-out side of the imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The first lens has negative focal power, and the surface of the first lens close to the light incidence side is a concave surface; the second lens has focal power; the third lens has focal power, and the surface of the third lens close to the light-emitting side is a convex surface; the fourth lens has negative focal power, and the Abbe number of the fourth lens is less than 20; the fifth lens has focal power; the sixth lens has focal power; wherein the maximum field angle FOV of the imaging system satisfies: FOV > 120.

Preferably, 121 ° < FOV < 140 °.

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 < 2.3. By limiting the f/EPD within a reasonable range, the imaging system can be ensured to have a larger aperture, so that the luminous flux of the imaging system is increased, the imaging effect in a dark environment is enhanced, meanwhile, the aberration of an edge field can be reduced, and the imaging quality of the imaging system is ensured. Preferably, 2.1 < f/EPD < 2.3.

In the present embodiment, the effective focal length f2 of the second lens and the effective focal length f5 of the fifth lens satisfy: f2/f5 is more than 1.0 and less than 2.5. By limiting f2/f5 within a reasonable range, the imaging system is favorable for better balancing aberration and improving the resolution of the imaging system. Preferably, 1.1 < f2/f5 < 2.4.

In the present embodiment, the radius of curvature R3 of the light entrance side surface of the second lens and the radius of curvature R11 of the light entrance side surface of the sixth lens satisfy: 2.0 < R3/R11 < 5.0. The ratio of the curvature radius of the surface of the second lens close to the light incident side to the curvature radius of the surface of the sixth lens close to the light incident side is limited in a certain range, so that the stability of assembling of an imaging system is improved. Preferably, 2.2 < R3/R11 < 4.8.

In the present embodiment, a curvature radius R9 of a surface of the fifth lens on the light incident side and a curvature radius R12 of a surface of the sixth lens on the light exit side satisfy: 1.5 < R9/R12 < 2.6. The ratio of the curvature radius of the surface of the fifth 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 limited in a certain range, so that the stability of assembling of an imaging system is improved. Preferably, 1.6 < R9/R12 < 2.45.

In the present embodiment, a curvature radius R3 of a surface of the second lens on the light incident side and a curvature radius R12 of a surface of the sixth lens on the light exit side satisfy: 2.0 < R3/R12 < 5.0. The ratio of the curvature radius of the surface of the second 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 limited in a certain range, so that the stability of assembling of an imaging system is improved. Preferably, 2.1 < R3/R12 < 4.9.

In the present embodiment, the central thickness CT1 of the first lens on the optical axis and the central thickness CT2 of the second lens on the optical axis satisfy: 1.5 < CT2/CT1 < 4.0. By controlling CT2/CT1 within a reasonable range, it is beneficial to improve the stability of lens assembly. Preferably, 1.6 < CT2/CT1 < 3.6.

In the present embodiment, the center thickness CT3 of the third lens on the optical axis and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 2.0 < CT3/T34 < 3.0. By limiting the CT3/T34 to a reasonable range, the imaging system can have less curvature of field to ensure the imaging quality of the imaging system. Preferably, 2.0 < CT3/T34 < 2.8.

In the present embodiment, the central thickness CT4 of the fourth lens on the optical axis and the central thickness CT6 of the sixth lens on the optical axis satisfy: CT6/CT4 is more than or equal to 1.5 and less than 2.0. By limiting the CT6/CT4 within a reasonable range, the lens assembly is facilitated, and the stability and convenience of the lens assembly are improved. Preferably, 1.5 ≦ CT6/CT4 < 1.99.

In this embodiment, the on-axis distance SAG11 from the intersection point of the surface of the first lens close to the light incident side and the optical axis to the effective radius vertex of the surface of the first lens close to the light incident side, and the on-axis distance SAG12 from the intersection point of the surface of the first lens close to the light emergent side and the optical axis to the effective radius vertex of the surface of the first lens close to the light emergent side satisfy: 1.0 < SAG12/SAG11 < 3.0. By controlling SAG12/SAG11 within a reasonable range, the primary light of the imaging system is favorably incident on the image surface with a smaller incident angle and higher relative illumination, and the first lens is favorably better processed. Preferably, 1.1 < SAG12/SAG11 < 2.8.

In this embodiment, the on-axis distance SAG52 between the intersection point of the light exit side surface of the fifth lens and the optical axis and the effective radius vertex of the light exit side surface of the fifth lens, and the on-axis distance SAG61 between the intersection point of the light entrance side surface of the sixth lens and the optical axis and the effective radius vertex of the light entrance side surface of the sixth lens satisfy: 0.5 < SAG61/SAG52 < 2.5. By controlling SAG61/SAG52 within a reasonable range, the fifth lens and the sixth lens are prevented from being too bent, the processing difficulty is reduced, and meanwhile, the imaging system has better stability. Preferably 0.55 < SAG61/SAG52 < 2.4.

In the present embodiment, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the imaging system satisfy: -4.0 < f12/f < -2.5. By limiting f12/f within a reasonable range, the imaging system is facilitated to have smaller spherical aberration, and good imaging quality of an on-axis field of view is ensured. Preferably, -3.9 < f12/f < -2.55.

In the present embodiment, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the imaging system satisfy: f34/f is more than 3.0 and less than 5.0. By controlling f34/f within a reasonable range, the imaging system can better balance the aberration, and the resolution of the imaging system can be improved. Preferably, 3.1 < f34/f < 4.95.

In the present embodiment, the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens, and the effective focal length f of the imaging system satisfy: f456/f is more than 3.0 and less than 5.5. By controlling f456/f within a reasonable range, the aberration of the marginal field of view is reduced, and the imaging quality of the imaging system is ensured. Preferably, 3.2 < f456/f < 5.4.

In the present embodiment, the abbe number V2 of the second lens satisfies: v2 < 25. By reducing the Abbe number of the lens, the chromatic aberration of the imaging system can be reduced, and the imaging quality of the imaging system is ensured. Preferably 20 < V2 < 25.

Example two

As shown in fig. 1 to 24, the lens from the light-in side of the imaging system to the light-out side of the imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The first lens has negative focal power, and the surface of the first lens close to the light incidence side is a concave surface; the second lens has focal power; the third lens has focal power, and the surface of the third lens close to the light-emitting side is a convex surface; the fourth lens has negative focal power, and the Abbe number of the fourth lens is less than 20; the fifth lens has focal power; the sixth lens has focal power; wherein, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the imaging system satisfy the following conditions: -4.0 < f12/f < -2.5.

By reasonably controlling the positive and negative distribution of the focal 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. By limiting f12/f within a reasonable range, the imaging system is facilitated to have smaller spherical aberration, and good imaging quality of an on-axis field of view is ensured.

Preferably, the combined focal length f12 of the first lens and the second lens and the effective focal length f of the imaging system satisfy that: -3.9 < f12/f < -2.55.

In the present embodiment, the effective focal length f2 of the second lens and the effective focal length f5 of the fifth lens satisfy: f2/f5 is more than 1.0 and less than 2.5. By limiting f2/f5 within a reasonable range, the imaging system is facilitated to better balance aberration, and the resolution of the imaging system is facilitated to be improved. Preferably, 1.1 < f2/f5 < 2.4.

In the present embodiment, the center thickness CT3 of the third lens on the optical axis and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 2.0 < CT3/T34 < 3.0. By limiting the CT3/T34 to a reasonable range, the imaging system can have a smaller curvature of field to ensure the imaging quality of the imaging system. Preferably, 2.0 < CT3/T34 < 2.8. In the present embodiment, the central thickness CT4 of the fourth lens on the optical axis and the central thickness CT6 of the sixth lens on the optical axis satisfy: CT6/CT4 is more than or equal to 1.5 and less than 2.0. By limiting the CT6/CT4 within a reasonable range, the lens assembly is facilitated, and the stability and convenience of the lens assembly are improved. Preferably, 1.5 ≦ CT6/CT4 < 1.99.

In this embodiment, the on-axis distance SAG11 from the intersection point of the surface of the first lens close to the light incident side and the optical axis to the effective radius vertex of the surface of the first lens close to the light incident side, and the on-axis distance SAG12 from the intersection point of the surface of the first lens close to the light emergent side and the optical axis to the effective radius vertex of the surface of the first lens close to the light emergent side satisfy: 1.0 < SAG12/SAG11 < 3.0. By controlling SAG12/SAG11 within a reasonable range, the main ray of the imaging system can be favorably incident on the image surface with a smaller incident angle and higher relative illumination, and the first lens can be favorably processed. Preferably, 1.1 < SAG12/SAG11 < 2.8.

In the present embodiment, the combined focal length f34 of the third lens and the fourth lens and the effective focal length f of the imaging system satisfy: f34/f is more than 3.0 and less than 5.0. By controlling f34/f within a reasonable range, the imaging system can balance the aberration better, and the resolution of the imaging system can be improved. Preferably, 3.1 < f34/f < 4.95.

Optionally, the above-described imaging system may further include a filter for correcting color deviation and/or a protective glass for protecting the photosensitive element located on the imaging surface.

The imaging system in the present application may employ a plurality of lenses, such as the six lenses described above. By reasonably distributing the focal power and the surface shape of each lens, 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 imaging system 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 six is applicable to all embodiments of the present application.

Example one

As shown in fig. 1 to 4, an imaging system of the first example 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: a first lens E1, a second lens E2, a stop STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.

The first lens element E1 has negative refractive power, and the surface S1 of the first lens element on the light incident side is concave, and the surface S2 of the first lens element on the light exit side is concave. The second lens element E2 has positive refractive power, and the surface S3 of the second lens element near the light incident side is convex, and the surface S4 of the second lens element near the light emergent side is concave. The third lens E3 has positive refractive power, and a surface S5 of the third lens near the light entrance side is convex, and a surface S6 of the third lens near the light exit side is convex. The fourth lens element E4 has negative power, and the surface S7 of the fourth lens element near the light entrance side is convex, and the surface S8 of the fourth lens element near the light exit side is concave. The fifth lens E5 has positive refractive power, and a surface S9 of the fifth lens near the light entrance side is convex, and a surface S10 of the fifth lens near the light exit side is convex. The sixth lens element E6 has positive refractive power, and the surface S11 of the sixth lens element on the light entrance side is convex, and the surface S12 of the sixth lens element on the light exit side is concave. The filter E7 has a surface S13 close to the light entrance side and a surface S14 close to the light exit side. 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 1.57mm, the total length TTL of the imaging system is 6.50mm, and the image height ImgH is 3.1 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, and the focal length are all millimeters (mm).

TABLE 1

In the first example, a surface of any one of the first lens E1 to the sixth lens E6 close to the light incident side and a surface close to the light emergent side are both 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 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.

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 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 4, the imaging system of example one can achieve good imaging quality.

Example two

As shown in fig. 5 to 8, 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. 5 shows a schematic diagram of the configuration of the imaging system of example two.

As shown in fig. 5, the image forming system sequentially includes from the light incident side to the light emergent side: a first lens E1, a second lens E2, a stop STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.

The first lens element E1 has negative power, and the surface S1 of the first lens element near the light entrance side is concave, and the surface S2 of the first lens element near the light exit side is concave. The second lens element E2 has positive refractive power, and the surface S3 of the second lens element near the light incident side is convex, and the surface S4 of the second lens element near the light emergent side is convex. The third lens E3 has positive refractive power, and a surface S5 of the third lens near the light entrance side is convex, and a surface S6 of the third lens near the light exit side is convex. The fourth lens element E4 has negative power, and the surface S7 of the fourth lens element near the light entrance side is convex, and the surface S8 of the fourth lens element near the light exit side is concave. The fifth lens E5 has positive refractive power, and a surface S9 of the fifth lens near the light entrance side is convex, and a surface S10 of the fifth lens near the light exit side is convex. The sixth lens element E6 has positive refractive power, and the surface S11 of the sixth lens element on the light entrance side is convex, and the surface S12 of the sixth lens element on the light exit side is concave. The filter E7 has a surface S13 close to the light entrance side and a surface S14 close to the light exit side. 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 1.57mm, the total length TTL of the imaging system is 6.50mm and the image height ImgH is 3.1mm °.

Table 3 shows a basic structural parameter table of the imaging system of example two, in which the units of the radius of curvature, thickness/distance, and focal length 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.

TABLE 4

Fig. 6 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. 7 shows astigmatism curves for the imaging system of example two, representing meridional and sagittal image planes. Fig. 8 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. 6 to 8, the imaging system of example two can achieve good imaging quality.

Example III

As shown in fig. 9 to 12, an imaging system of example three of the present application is described. Fig. 9 shows a schematic diagram of the configuration of an imaging system of example three.

As shown in fig. 9, the imaging system sequentially includes, from the light incident side to the light emergent side: a first lens E1, a second lens E2, a stop STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.

The first lens element E1 has negative refractive power, and the surface S1 of the first lens element on the light incident side is concave, and the surface S2 of the first lens element on the light exit side is concave. The second lens element E2 has positive refractive power, and the surface S3 of the second lens element near the light incident side is convex, and the surface S4 of the second lens element near the light emergent side is convex. The third lens E3 has positive refractive power, and a surface S5 of the third lens near the light entrance side is convex, and a surface S6 of the third lens near the light exit side is convex. The fourth lens element E4 has negative power, and the surface S7 of the fourth lens element near the light entrance side is convex, and the surface S8 of the fourth lens element near the light exit side is concave. The fifth lens E5 has positive refractive power, and a surface S9 of the fifth lens near the light entrance side is convex, and a surface S10 of the fifth lens near the light exit side is convex. The sixth lens element E6 has positive refractive power, and the surface S11 of the sixth lens element on the light entrance side is convex, and the surface S12 of the sixth lens element on the light exit side is concave. The filter E7 has a surface S13 close to the light entrance side and a surface S14 close to the light exit side. 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 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, and focal length 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. 10 shows on-axis chromatic aberration curves for the imaging system of example three, which represent the deviation of the convergent focus for light rays of different wavelengths after passing through the imaging system. FIG. 11 shows astigmatism curves for the imaging system of example three, representing meridional and sagittal image planes. Fig. 12 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. 10 to 12, the imaging system of example three can achieve good imaging quality.

Example four

As shown in fig. 13 to 16, an imaging system of the present example four is described. Fig. 13 shows a schematic diagram of the imaging system configuration of example four.

As shown in fig. 13, the imaging system sequentially includes, from the light incident side to the light emergent side: a first lens E1, a second lens E2, a stop STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.

The first lens element E1 has negative refractive power, and the surface S1 of the first lens element on the light incident side is concave, and the surface S2 of the first lens element on the light exit side is concave. The second lens element E2 has positive refractive power, and the surface S3 of the second lens element near the light incident side is convex, and the surface S4 of the second lens element near the light emergent side is concave. The third lens E3 has positive refractive power, and a surface S5 of the third lens near the light entrance side is convex, and a surface S6 of the third lens near the light exit side is convex. The fourth lens element E4 has negative refractive power, and the surface S7 of the fourth lens element on the light entrance side is concave, and the surface S8 of the fourth lens element on the light exit side is concave. The fifth lens E5 has positive refractive power, and a surface S9 of the fifth lens near the light entrance side is convex, and a surface S10 of the fifth lens near the light exit side is convex. The sixth lens element E6 has positive refractive power, and the surface S11 of the sixth lens element on the light entrance side is convex, and the surface S12 of the sixth lens element on the light exit side is concave. The filter E7 has a surface S13 close to the light entrance side and a surface S14 close to the light exit side. 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, and focal length 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

A16

S1

1.6964E+00

-3.8705E-01

1.3309E-01

-5.7054E-02

2.1911E-02

-1.2735E-02

4.1455E-03

S2

4.5333E-01

-1.7280E-01

4.3417E-03

-6.1189E-03

4.7438E-03

8.1964E-04

3.0424E-04

S3

-7.5690E-02

-2.5637E-02

3.6834E-03

3.6895E-04

2.7596E-04

-1.6025E-05

9.6140E-05

S4

3.3825E-03

1.0163E-03

2.0407E-04

1.7874E-05

2.5552E-05

2.3269E-05

2.1168E-05

S5

1.3866E-02

-1.1889E-03

-2.6871E-04

3.3578E-05

2.5971E-05

1.1576E-05

-1.5484E-05

S6

-1.0279E-01

-2.0108E-03

5.6417E-04

3.0741E-04

-1.0183E-04

-1.4720E-05

2.5400E-05

S7

-3.3940E-01

1.8807E-02

3.0045E-03

2.9944E-03

-9.1291E-04

-2.3023E-04

-1.4656E-04

S8

6.3640E-03

8.8967E-02

-5.0959E-03

4.0915E-03

3.6577E-03

6.6274E-04

9.0737E-04

S9

-6.7787E-01

1.1446E-01

-4.0488E-02

1.0755E-02

-7.7655E-03

3.6105E-03

-2.1933E-03

S10

-1.0004E-01

1.5187E-01

-7.2916E-02

1.6930E-02

-7.1183E-03

4.5928E-03

-4.8123E-03

S11

-2.9293E+00

5.9948E-01

-1.2450E-01

4.4094E-02

-2.6933E-02

5.3094E-03

3.1650E-03

S12

-5.1434E+00

1.0775E+00

-3.2213E-01

1.0733E-01

-4.2033E-02

2.8451E-02

-1.4583E-02

Flour mark

A18

A20

A22

A24

A26

A28

A30

S1

-3.4471E-03

7.2555E-04

-1.0388E-03

1.0104E-04

-2.9059E-04

7.5707E-06

-5.9230E-05

S2

8.9615E-05

9.3605E-06

8.6477E-05

1.2589E-06

5.7052E-05

7.6573E-06

1.8270E-05

S3

3.5819E-05

1.6733E-05

6.8933E-06

1.3808E-07

-2.0110E-06

-3.9575E-06

-1.6258E-06

S4

1.4841E-05

9.2912E-06

1.0051E-05

1.0657E-05

1.0042E-05

6.6837E-06

2.7888E-06

S5

-2.4607E-05

-1.6931E-05

-3.3170E-06

7.3672E-06

8.4842E-06

5.0348E-06

1.4399E-06

S6

4.2729E-05

3.0301E-05

9.3754E-06

-1.2012E-05

-2.3894E-05

-1.7818E-05

-7.5894E-06

S7

1.4625E-04

6.3682E-05

4.3321E-05

3.7324E-06

6.6087E-06

3.0641E-06

2.9825E-06

S8

2.9472E-04

2.6607E-04

8.6110E-05

8.9177E-05

2.1151E-05

8.9942E-06

6.1839E-06

S9

6.7208E-04

-6.6166E-05

7.3526E-04

2.8263E-04

3.1348E-04

8.2058E-05

5.7997E-05

S10

-1.3682E-03

1.2513E-03

1.3107E-03

-5.9510E-04

-9.6474E-04

-5.5241E-04

-1.4419E-04

S11

-3.2437E-04

-5.9525E-04

-2.8122E-05

2.1913E-04

-5.5832E-05

-5.2446E-05

2.1626E-05

S12

-3.8397E-03

-7.4827E-04

2.1319E-03

1.5857E-03

8.9344E-04

1.9132E-04

-5.4556E-04

TABLE 8

Fig. 14 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. 15 shows astigmatism curves of the imaging system of example four, which represent meridional field curvature and sagittal field curvature. Fig. 16 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. 14 to 16, the imaging system given in example four can achieve good imaging quality.

Example five

As shown in fig. 17 to 20, an imaging system of example five of the present application is described. Fig. 17 shows a schematic diagram of the imaging system configuration of example five.

As shown in fig. 17, the imaging system sequentially includes, from the light incident side to the light emergent side: a first lens E1, a second lens E2, a stop STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming 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, and focal length 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.

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

1.7424E+00

-3.8536E-01

1.3343E-01

-5.5956E-02

2.1357E-02

-1.1851E-02

4.3207E-03

S2

4.6478E-01

-1.6973E-01

-7.1368E-03

-5.9484E-03

5.9748E-03

2.1254E-03

2.2827E-04

S3

-7.9480E-02

-2.3910E-02

3.0937E-03

4.6393E-04

4.5915E-04

7.5473E-05

6.7287E-05

S4

1.9917E-03

7.2961E-04

1.1040E-04

-2.5833E-05

2.7328E-05

5.2646E-05

7.8495E-05

S5

5.4046E-03

-9.9563E-04

-1.4424E-04

-3.0530E-06

7.4915E-06

4.4072E-06

5.6701E-06

S6

-1.0048E-01

1.6742E-03

-4.0013E-04

2.5292E-04

-1.6618E-04

7.6380E-06

-2.1837E-05

S7

-3.3431E-01

2.5793E-02

3.1534E-04

2.9972E-03

-6.3919E-04

1.5396E-04

-1.5377E-04

S8

-4.7756E-01

7.7345E-02

-1.2201E-02

6.3824E-03

-2.4977E-03

1.0580E-03

-5.2581E-04

S9

-6.5572E-01

1.0979E-01

-4.4857E-02

1.3426E-02

-7.9643E-03

4.0803E-03

-2.6962E-03

S10

-1.3294E-01

1.4243E-01

-9.0440E-02

2.2989E-02

-5.1977E-03

4.4930E-03

-6.4036E-03

S11

-2.9545E+00

6.1493E-01

-1.1802E-01

2.8534E-02

-2.4901E-02

7.1824E-03

4.6134E-03

S12

-5.1588E+00

1.0882E+00

-3.3298E-01

1.1994E-01

-3.9597E-02

2.7872E-02

-1.6548E-02

Flour mark

A18

A20

A22

A24

A26

A28

A30

S1

-2.8727E-03

9.5481E-04

-7.5019E-04

2.1431E-04

-2.0356E-04

2.5125E-05

-4.8826E-05

S2

-6.4242E-04

-7.1793E-04

-3.7267E-04

-1.5497E-04

1.3622E-05

1.5253E-05

1.3809E-05

S3

-1.1817E-05

-1.3090E-05

-5.1222E-06

-4.4359E-06

-2.5572E-06

-2.7296E-06

-8.1623E-07

S4

8.0700E-05

7.5866E-05

6.2775E-05

4.5957E-05

2.6405E-05

1.1436E-05

2.5303E-06

S5

3.0059E-07

2.7736E-07

-1.6502E-06

-2.1455E-06

-2.5705E-06

-1.4288E-06

-3.8644E-07

S6

1.8741E-05

-3.1708E-06

7.1137E-06

5.9222E-06

7.4140E-06

4.3867E-06

1.5649E-06

S7

1.0331E-04

2.8618E-05

3.9479E-05

6.3347E-06

8.0111E-06

2.5468E-06

1.9483E-06

S8

2.0279E-04

-9.9064E-05

4.4657E-05

-2.0914E-05

5.3889E-06

-1.9269E-06

-1.0527E-07

S9

1.2252E-03

-1.9124E-04

5.9499E-04

1.1789E-04

2.0457E-04

2.9267E-05

4.5904E-05

S10

-6.3456E-04

8.7240E-04

5.9470E-04

-1.8144E-04

1.5647E-04

1.2739E-04

6.8752E-05

S11

-9.6292E-04

-4.5344E-04

9.3608E-05

2.0773E-04

-4.5036E-05

-1.1987E-04

2.2317E-05

S12

-3.7778E-03

-1.4834E-03

1.6495E-03

2.2531E-03

7.6268E-04

2.1471E-04

-4.2671E-04

Watch 10

Fig. 18 shows on-axis chromatic aberration curves for the imaging system of example five, which represent the deviation of the convergent focus for light rays of different wavelengths after passing through the imaging system. FIG. 19 shows astigmatism curves for the imaging system of example five, representing meridional and sagittal image planes. Fig. 20 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. 18 to 20, the imaging system given in example five can achieve good imaging quality.

Example six

As shown in fig. 21 to 24, an imaging system of example six of the present application is described. Fig. 21 shows a schematic diagram of the configuration of an imaging system of example six.

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

The first lens element E1 has negative refractive power, and the surface S1 of the first lens element on the light incident side is concave, and the surface S2 of the first lens element on the light exit side is concave. The second lens element E2 has positive refractive power, and the surface S3 of the second lens element near the light incident side is convex, and the surface S4 of the second lens element near the light emergent side is concave. The third lens E3 has positive refractive power, and a surface S5 of the third lens near the light entrance side is convex, and a surface S6 of the third lens near the light exit side is convex. The fourth lens element E4 has negative power, and the surface S7 of the fourth lens element near the light entrance side is convex, and the surface S8 of the fourth lens element near the light exit side is concave. The fifth lens element E5 has positive refractive power, and the surface S9 of the fifth lens element on the light incident side is convex, and the surface S10 of the fifth lens element on the light exit side is concave. The sixth lens element E6 has positive refractive power, and the surface S11 of the sixth lens element on the light entrance side is convex, and the surface S12 of the sixth lens element on the light exit side is concave. The filter E7 has a surface S13 close to the light entrance side and a surface S14 close to the light exit side. 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 1.57mm, the total length TTL of the imaging system is 6.50mm, and the image height ImgH is 3.1mm °.

Table 11 shows a basic structural parameter table of the imaging system of example six, in which the units of the radius of curvature, thickness/distance, and focal length 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

A14

A16

S1

1.9180E+00

-3.6695E-01

1.4502E-01

-5.5007E-02

2.0488E-02

-1.2409E-02

3.9138E-03

S2

4.4868E-01

-1.5978E-01

-1.1479E-02

-1.5092E-03

6.7063E-03

8.0761E-04

-1.8759E-03

S3

-1.2925E-01

-1.9461E-02

6.6361E-03

-1.5422E-04

-4.2298E-04

-3.0559E-04

1.4206E-04

S4

-2.1540E-04

1.1103E-03

2.6221E-04

3.8923E-05

4.0435E-05

2.5818E-05

2.8480E-05

S5

1.1212E-02

-1.1940E-03

-3.7445E-04

-6.7415E-05

-2.6888E-05

1.3675E-05

3.6522E-05

S6

-1.1944E-01

6.6001E-03

-8.8603E-04

-1.8746E-04

-4.5719E-04

-4.3729E-05

8.2207E-05

S7

-3.3373E-01

3.0311E-02

-2.3405E-04

2.0820E-03

-6.8796E-04

1.4286E-04

-2.3938E-04

S8

-4.6073E-01

7.7029E-02

-1.0678E-02

5.1585E-03

-2.2461E-03

9.6191E-04

-5.3980E-04

S9

-6.7555E-01

1.0091E-01

-3.5456E-02

1.1000E-02

-6.6815E-03

4.4921E-03

-2.3816E-03

S10

-2.6746E-01

1.8523E-01

-9.0686E-02

2.3298E-02

-1.1451E-02

6.2053E-03

-7.1631E-03

S11

-3.0004E+00

6.3984E-01

-9.1599E-02

8.6671E-03

-1.9795E-02

4.5380E-03

5.3129E-03

S12

-4.9953E+00

1.0985E+00

-3.0590E-01

8.1604E-02

-2.6224E-02

1.8208E-02

-1.4551E-02

Flour mark

A18

A20

A22

A24

A26

A28

A30

S1

-2.3550E-03

1.4536E-03

-2.7700E-04

4.7467E-04

-7.2136E-05

6.9514E-05

-3.4741E-05

S2

-1.9308E-03

-1.1819E-03

-7.0852E-04

-5.2847E-04

-3.4069E-04

-1.7468E-04

-5.1427E-05

S3

1.2850E-04

6.3796E-05

2.1402E-05

5.4443E-06

-4.1791E-07

-1.7067E-06

-8.5921E-08

S4

1.9426E-05

1.7234E-05

1.5981E-05

1.7076E-05

1.3504E-05

8.0392E-06

2.1754E-06

S5

2.8369E-05

1.0649E-05

8.4333E-07

-3.4945E-06

-1.6986E-06

-1.0275E-06

1.3312E-07

S6

1.5981E-04

7.6476E-05

1.7178E-05

-2.7106E-05

-2.9731E-05

-2.0103E-05

-7.5260E-06

S7

4.4255E-05

-2.7407E-05

2.3611E-05

-3.7689E-06

6.5544E-06

2.7560E-07

3.2319E-06

S8

2.0753E-04

-1.1352E-04

4.8168E-05

-2.3545E-05

6.8357E-06

-2.3961E-06

9.0876E-07

S9

1.2494E-03

-4.6828E-04

4.4122E-04

-9.3704E-05

1.2344E-04

-1.9452E-05

3.1956E-05

S10

-2.9752E-04

7.7044E-04

8.9519E-04

-1.3408E-05

3.1398E-04

2.5613E-04

1.7098E-04

S11

-1.8804E-03

-6.3807E-04

1.7087E-04

2.4815E-04

2.1003E-04

-1.2821E-04

-2.4039E-05

S12

-6.7062E-03

2.2968E-03

1.6579E-03

4.0505E-03

5.8735E-04

5.8636E-04

-3.2362E-04

TABLE 12

Fig. 22 shows an on-axis chromatic aberration curve of the imaging system of example six, which represents the convergent focus deviation of light rays of different wavelengths after passing through the imaging system. Fig. 23 shows astigmatism curves representing meridional field curvature and sagittal field curvature of the imaging system of example six. Fig. 24 shows a chromatic aberration of magnification curve of the imaging system of example six, 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. 22 to 24, the imaging system of example six can achieve good imaging quality.

To sum up, examples one to six satisfy the relationships shown in table 13, respectively.

Watch 13

Table 14 gives the effective focal lengths f of the imaging systems of example one to example six, and the effective focal lengths f1 to f6 of the respective lenses.

Example parameters	1	2	3	4	5	6
							f(mm)	1.57	1.57	1.57	1.57	1.57	1.57
f1(mm)	-1.96	-2.23	-2.11	-2	-2.05	-2.13
							f2(mm)	4.58	5.47	4.52	4.41	5.2	4.96
f3(mm)	2.46	2.47	2.54	2.41	2.3	2.37
							f4(mm)	-3.07	-2.76	-2.96	-2.77	-3.16	-3.26
f5(mm)	2.56	2.49	2.67	2.47	2.75	3.55
							f6(mm)	20.53	19.96	15.54	17.56	17.03	7.3
TTL(mm)	6.50	6.50	6.50	6.50	6.50	6.50
							ImgH(mm)	3.10	3.10	3.10	3.10	3.10	3.10
Semi-FOV(°)	63.8	61.4	61.9	62.0	62.2	61.4

TABLE 14

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 from an entrance side of the imaging system to an exit side of the imaging system, comprising:

the surface of the first lens, which is close to the light incidence side, is a concave surface;

a second lens having an optical power;

the surface of the third lens, which is close to the light-emitting side, is a convex surface;

a fourth lens having a negative optical power, the fourth lens having an Abbe number less than 20;

a fifth lens having optical power;

a sixth lens having optical power;

wherein a maximum field angle FOV of the imaging system satisfies: FOV > 120.

2. 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 < 2.3.

3. The imaging system of claim 1, wherein an effective focal length f2 of the second lens and an effective focal length f5 of the fifth lens satisfy: 1.0 < f2/f5 < 2.5.

4. The imaging system of claim 1, wherein a radius of curvature R3 of the light-entrance-side surface of the second lens and a radius of curvature R11 of the light-entrance-side surface of the sixth lens satisfy: 2.0 < R3/R11 < 5.0.

5. The imaging system of claim 1, wherein a curvature radius R9 of a surface of the fifth lens close to the light inlet side and a curvature radius R12 of a surface of the sixth lens close to the light outlet side satisfy that: 1.5 < R9/R12 < 2.6.

6. The imaging system of claim 1, wherein a curvature radius R3 of a surface of the second lens close to the light incident side and a curvature radius R12 of a surface of the sixth lens close to the light exit side satisfy: 2.0 < R3/R12 < 5.0.

7. The imaging system of claim 1, wherein a center thickness CT1 of the first lens on an optical axis and a center thickness CT2 of the second lens on the optical axis satisfy: 1.5 < CT2/CT1 < 4.0.

8. The imaging system of claim 1, wherein a center thickness CT3 of the third lens on an optical axis and an air spacing T34 of the third lens and the fourth lens on the optical axis satisfy: 2.0 < CT3/T34 < 3.0.

9. The imaging system of claim 1, wherein a center thickness CT4 of the fourth lens on an optical axis and a center thickness CT6 of the sixth lens on the optical axis satisfy: CT6/CT4 is more than or equal to 1.5 and less than 2.0.

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

a second lens having an optical power;

a fifth lens having optical power;

a sixth lens having optical power;

wherein the combined focal length f12 of the first lens and the second lens and the effective focal length f of the imaging system satisfy the following conditions: -4.0 < f12/f < -2.5.