CN210119626U

CN210119626U - Optical imaging system

Info

Publication number: CN210119626U
Application number: CN201920987527.6U
Authority: CN
Inventors: 张晓彬; 谢桂华; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-02-28
Anticipated expiration: 2029-06-28

Abstract

The application discloses an optical imaging system, which comprises in order from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens having optical power. The object side surface of the first lens is a concave surface, and the image side surface of the first lens is a convex surface; the sixth lens has positive focal power; the seventh lens has negative focal power, and the object side surface of the seventh lens is a convex surface; wherein, the half ImgH of the diagonal length of the effective pixel area on the imaging surface of the optical imaging system satisfies that ImgH is more than 6mm and less than 7 mm; and the total effective focal length f of the optical imaging system and the effective focal length f6 of the sixth lens meet f/f6 is more than or equal to 0.22 and less than 1.

Description

Optical imaging system

Technical Field

The present application relates to an optical imaging system, and more particularly, to an optical imaging system including seven lenses.

Background

With the rapid development of portable electronic devices, users have increasingly stringent requirements for imaging quality and other photographing functions of portable electronic devices such as smart phones. The imaging lens of the mobile phone is required to have higher resolution, larger field range, more effective brightness and higher signal-to-noise ratio, which means that the imaging lens of the mobile phone has the characteristics of large image plane, large wide angle and large aperture. Generally, further improvement of imaging quality by increasing the number of lenses is a major approach to improve imaging of cell phones. However, the improvement of the imaging quality by simply increasing the number of the lenses is obviously not beneficial to the miniaturization of the lens, and does not meet the requirement of the market on the thinning of the mobile phone. How to design a lens with a larger image plane, a larger wide angle and a larger aperture under the condition of ensuring the imaging quality and keeping the size of the lens unchanged or even smaller is a problem to be solved urgently at present.

SUMMERY OF THE UTILITY MODEL

The present application provides an optical imaging system, such as a large image plane wide-angle lens, applicable to portable electronic products, which may solve at least or partially at least one of the above-mentioned disadvantages of the prior art.

An aspect of the present application provides an optical imaging system, in order from an object side to an image side along an optical axis, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens having optical power. The object side surface of the first lens can be a concave surface, and the image side surface of the first lens can be a convex surface; the sixth lens may have a positive optical power; the seventh lens may have a negative optical power.

In one embodiment, ImgH, which is half the diagonal length of the effective pixel area on the imaging plane of the optical imaging system, may satisfy 6mm < ImgH < 7 mm.

In one embodiment, the total effective focal length f of the optical imaging system and the effective focal length f6 of the sixth lens can satisfy 0.22 ≦ f/f6 < 1.

In one embodiment, a half of a maximum field angle of the optical imaging system and a total effective focal length f of the optical imaging system may satisfy 2mm < tan (HFOV/2) × f < 2.9 mm.

In one embodiment, the effective focal length f4 of the fourth lens and the entrance pupil diameter EPD of the optical imaging system may satisfy 2 < | f4/EPD | < 3.

In one embodiment, the maximum effective radius DT31 of the object-side surface of the third lens and the maximum effective radius DT21 of the object-side surface of the second lens may satisfy 0.5 < DT31/DT21 < 1.

In one embodiment, a separation distance T34 on the optical axis of the third and fourth lenses, a separation distance T67 on the optical axis of the sixth and seventh lenses, and a distance TTL on the optical axis from the object-side surface of the first lens to the imaging surface of the optical imaging system may satisfy 0 < (T34+ T67)/TTL < 0.5.

In one embodiment, the central thickness CT4 of the fourth lens on the optical axis, the central thickness CT5 of the fifth lens on the optical axis, the central thickness CT6 of the sixth lens on the optical axis, and the total effective focal length f of the optical imaging system may satisfy 0 < (CT4+ CT5+ CT6)/f < 0.6.

In one embodiment, the radius of curvature of the object-side surface of the seventh lens, R13, the radius of curvature of the image-side surface of the seventh lens, R14, and the effective focal length f7 of the seventh lens may satisfy-0.5 < (R13+ R14)/f7 < 0.

In one embodiment, the radius of curvature R1 of the object-side surface of the first lens and the radius of curvature R2 of the image-side surface of the first lens can satisfy 0.6 < R1/R2 ≦ 1.5.

In one embodiment, a radius of curvature R11 of an object-side surface of the sixth lens and a radius of curvature R12 of an image-side surface of the sixth lens may satisfy 0 < (R12-R11)/(R12+ R11) < 0.5.

In one embodiment, the center thickness CTi of the ith lens on the optical axis may satisfy CTi < 1mm, where i is 1,2,3,4,5,6, or 7.

In one embodiment, ImgH which is half the diagonal length of the effective pixel region on the imaging surface of the optical imaging system, the radius of curvature R7 of the object-side surface of the fourth lens, and the radius of curvature R8 of the image-side surface of the fourth lens may satisfy 1.01 ≦ ImgH/| R7+ R8| < 1.3.

The optical imaging lens comprises seven lenses, and the optical focal power, the surface type, the center thickness of each lens, the axial distance between the lenses and the like are reasonably distributed, so that the optical imaging lens has at least one beneficial effect of miniaturization, high imaging quality, large image plane, wide angle, large aperture and the like.

Drawings

Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments when taken in conjunction with the accompanying drawings. In the drawings:

fig. 1 shows a schematic configuration diagram of an optical imaging system according to embodiment 1 of the present application;

fig. 2A to 2D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a magnification chromatic aberration curve, respectively, of the optical imaging system of embodiment 1;

fig. 3 shows a schematic configuration diagram of an optical imaging system according to embodiment 2 of the present application;

fig. 4A to 4D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the optical imaging system of embodiment 2;

fig. 5 shows a schematic configuration diagram of an optical imaging system according to embodiment 3 of the present application;

fig. 6A to 6D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the optical imaging system of embodiment 3;

fig. 7 shows a schematic configuration diagram of an optical imaging system according to embodiment 4 of the present application;

fig. 8A to 8D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the optical imaging system of embodiment 4;

fig. 9 shows a schematic configuration diagram of an optical imaging system according to embodiment 5 of the present application;

fig. 10A to 10D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the optical imaging system of embodiment 5;

fig. 11 shows a schematic configuration diagram of an optical imaging system according to embodiment 6 of the present application;

fig. 12A to 12D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the optical imaging system of embodiment 6;

fig. 13 is a schematic structural view showing an optical imaging system according to embodiment 7 of the present application;

fig. 14A to 14D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, of the optical imaging system of embodiment 7.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

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 closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including 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. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

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 application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The features, principles, and other aspects of the present application are described in detail below.

The optical imaging system according to the exemplary embodiment of the present application may include, for example, seven lenses having optical powers, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The seven lenses are arranged in sequence from the object side to the image side along the optical axis. In the first to seventh lenses, any adjacent two lenses may have an air space therebetween.

In an exemplary embodiment, the object side surface of the first lens may be concave, and the image side surface may be convex; the sixth lens may have a positive optical power; the seventh lens element may have a negative power and the object side surface may be convex.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 6mm < ImgH < 7mm, where ImgH is half the diagonal length of the effective pixel area on the imaging plane of the optical imaging system. More specifically, ImgH can further satisfy 6.30mm ≦ ImgH ≦ 6.60 mm. The condition that ImgH is more than 6mm and less than 7mm can be met, so that the imaging system has a larger image surface and the characteristic of high resolution is realized.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 0.22 ≦ f/f6 < 1, where f is the total effective focal length of the optical imaging system, and f6 is the effective focal length of the sixth lens. More specifically, f and f6 further satisfy 0.20. ltoreq. f/f 6. ltoreq.0.80. The conditional expression f/f6 is more than or equal to 0.22 and less than 1, so that the effective focal length of the sixth lens is restricted, the light convergence of the sixth lens is facilitated, the effective aperture of the seventh lens is controlled, and the manufacturability of the seventh lens is improved.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 2mm < tan (HFOV/2) × f < 2.9mm, where HFOV is half of the maximum field angle of the optical imaging system and f is the total effective focal length of the optical imaging system. More specifically, HFOV and f further may satisfy 2.30 mm. ltoreq. tan (HFOV/2). ltoreq.20mm. By restricting the maximum half field angle of the imaging system and controlling the effective focal length of the imaging system, the imaging effect of the large image plane of the system can be realized.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 2 < | f4/EPD | < 3, where f4 is an effective focal length of the fourth lens and EPD is an entrance pupil diameter of the optical imaging system. More specifically, f4 and EPD further satisfy 2.10 ≦ f4/EPD | ≦ 2.80. Through the effective focal length of the reasonable distribution fourth lens and the entrance pupil diameter of the constraint imaging system, the imaging system with a large image surface has a large caliber, the system can be ensured to have a small F number, and the imaging effect under a dark environment is enhanced.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 0.5 < DT31/DT21 < 1, where DT31 is the maximum effective radius of the object-side surface of the third lens and DT21 is the maximum effective radius of the object-side surface of the second lens. More specifically, DT31 and DT21 may further satisfy 0.80 ≦ DT31/DT21 ≦ 0.95. By limiting the ratio of the maximum effective radius of the object-side surface of the second lens to the maximum effective radius of the object-side surface of the third lens to a reasonable range, the light converging capability of the second lens can be controlled. On one hand, the size of the lens can be reduced, and the miniaturization of the lens is met; on the other hand, the resolution can be improved.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 0 < (T34+ T67)/TTL < 0.5, where TTL is a distance on an optical axis from an object side surface of the first lens to an imaging surface of the optical imaging system, T34 is a separation distance on the optical axis of the third lens and the fourth lens, and T67 is a separation distance on the optical axis of the sixth lens and the seventh lens. More specifically, T34, T67, and TTL can further satisfy 0.15 ≦ (T34+ T67)/TTL ≦ 0.30. By reasonably controlling the ratio of the air space of the third lens and the fourth lens on the optical axis to the sum of the air space of the sixth lens and the seventh lens on the optical axis to the total optical length, the risk of ghost images of the system can be effectively reduced, and the size compression of the lens group is facilitated.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 0 < (CT4+ CT5+ CT6)/f < 0.6, where CT4 is a central thickness of the fourth lens on the optical axis, CT5 is a central thickness of the fifth lens on the optical axis, CT6 is a central thickness of the sixth lens on the optical axis, and f is a total effective focal length of the optical imaging system. More specifically, CT4, CT5, CT6 and f can further satisfy 0.20 ≦ (CT4+ CT5+ CT6)/f ≦ 0.50. By controlling the sum of the center thicknesses of the fourth lens, the fifth lens, and the sixth lens, the following advantages can be obtained: the size of the system is favorably shortened, and the miniaturization of the system is realized; the spherical aberration and the axial chromatic aberration of the system can be corrected; the ghost image risk caused by the internal reflection of the lens is avoided.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression-0.5 < (R13+ R14)/f7 < 0, where R13 is a radius of curvature of an object-side surface of the seventh lens, R14 is a radius of curvature of an image-side surface of the seventh lens, and f7 is an effective focal length of the seventh lens. More specifically, R13, R14 and f7 may further satisfy-0.40. ltoreq. R13+ R14)/f 7. ltoreq-0.15. The effective caliber of the seventh lens is favorably reduced by controlling the curvature radiuses of the object side surface and the image side surface of the seventh lens and the effective focal length of the seventh lens, and meanwhile, the center thickness of the seventh lens is favorably controlled, so that the seventh lens has good processability. Alternatively, the object-side surface of the seventh lens element can be convex and the image-side surface can be concave.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 0.6 < R1/R2 ≦ 1.5, where R1 is a radius of curvature of an object-side surface of the first lens and R2 is a radius of curvature of an image-side surface of the first lens. More specifically, R1 and R2 may further satisfy 0.80. ltoreq. R1/R2. ltoreq.1.40. By controlling the ratio of the radius of curvature of the object-side surface to the radius of curvature of the image-side surface of the first lens, the light converging power of the first lens is controlled. When the ratio is between 0.6 and 1.5, the first lens power is small and correction of system aberration is facilitated. Alternatively, the object-side surface of the first lens element can be concave and the image-side surface can be convex.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 0 < (R12-R11)/(R12+ R11) < 0.5, where R11 is a radius of curvature of an object-side surface of the sixth lens and R12 is a radius of curvature of an image-side surface of the sixth lens. More specifically, R11 and R12 may further satisfy 0.05 ≦ (R12-R11)/(R12+ R11) ≦ 0.30. The curvature radius of the object side surface and the curvature radius of the image side surface of the sixth lens are controlled, so that the ratio of the edge thickness to the medium thickness of the sixth lens can be controlled, and the manufacturability of the sixth lens is improved. Alternatively, the object-side surface of the sixth lens element can be convex and the image-side surface can be concave.

In an exemplary embodiment, in the optical imaging system of the present application, the center thicknesses of the respective lenses (first to seventh lenses) on the optical axis are each less than 1mm, that is, the optical imaging system of the present application may satisfy the conditional expression CTi < 1mm, where i ═ 1,2,3,4,5,6, or 7. By controlling the central thickness of any lens, on one hand, the total length of the lens is favorably reduced, and the size of the lens is shortened; on the other hand, the method is beneficial to the molding of the lens and easy to process and manufacture the lens.

In an exemplary embodiment, the optical imaging system of the present application may satisfy the conditional expression 1.01 ≦ ImgH/| R7+ R8| < 1.3, where ImgH is a half of a diagonal length of an effective pixel region on an imaging surface of the optical imaging system, R7 is a radius of curvature of an object-side surface of the fourth lens, and R8 is a radius of curvature of an image-side surface of the fourth lens. More specifically, ImgH, R7, and R8 can further satisfy 1.01. ltoreq. ImgH/| R7+ R8| ≦ 1.20. The absolute value ratio of the image height to the sum of the curvature radii of the object side surface and the image side surface of the fourth lens is reasonably controlled, so that on one hand, the shape of the fourth lens is favorably controlled, and the lens is conveniently molded; on the other hand, the relative illumination of the marginal field of view is improved. Alternatively, the object-side surface of the fourth lens element can be concave and the image-side surface can be convex.

In an exemplary embodiment, the optical imaging system may further include a diaphragm. The diaphragm may be disposed at an appropriate position as needed, for example, between the second lens and the third lens. Optionally, the optical imaging system may further include a filter for correcting color deviation and/or a protective glass for protecting the photosensitive element on the imaging surface.

The optical imaging system according to the above-described embodiment of the present application may employ a plurality of lenses, such as the seven lenses described above. By reasonably distributing the focal power, the surface type, the central thickness of each lens, the on-axis distance between each lens and the like, the volume of the imaging system can be effectively reduced, the sensitivity of the imaging system can be reduced, and the processability of the imaging system can be improved, so that the optical imaging system is more favorable for production and processing and can be suitable for portable electronic products. The optical imaging system has the characteristics of large image plane, large wide angle and large aperture, and can better meet the application requirements of the imaging lens on the smart phone.

In the embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the object-side surface of the first lens to the image-side surface of the seventh 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. Optionally, at least one of an object-side surface and an image-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens is an aspheric mirror surface. Optionally, each of the first, second, third, fourth, fifth, sixth, and seventh lenses has an object-side surface and an image-side surface that are aspheric mirror surfaces.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the optical imaging system may be varied to achieve the various results and advantages described in the present specification without departing from the claimed subject matter. For example, although seven lenses are exemplified in the embodiment, the optical imaging system is not limited to include seven lenses. The optical imaging system may also include other numbers of lenses, if desired.

Specific examples of the optical imaging system that can be applied to the above-described embodiments are further described below with reference to the drawings.

Example one

An optical imaging system according to embodiment 1 of the present application is described below with reference to fig. 1 to 2D. Fig. 1 shows a schematic configuration diagram of an optical imaging system according to embodiment 1 of the present application.

As shown in fig. 1, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

The first lens element E1 has negative power, and has a concave object-side surface S1 and a convex image-side surface S2; the second lens element E2 has positive power, and has a convex object-side surface S3 and a concave image-side surface S4; the third lens element E3 has positive power, and has a convex object-side surface S5 and a convex image-side surface S6; the fourth lens element E4 has negative power, and has a concave object-side surface S7 and a convex image-side surface S8; the fifth lens element E5 has positive power, and has a concave object-side surface S9 and a convex image-side surface S10; the sixth lens element E6 has positive power, and has a convex object-side surface S11 and a concave image-side surface S12; the seventh lens element E7 has negative power, and has a convex object-side surface S13 and a concave image-side surface S14; filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

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

TABLE 1

In this embodiment, the total effective focal length f of the optical imaging system is 5.31mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 7.90mm, the half ImgH of the diagonal length of the effective pixel area on the imaging surface S17 is 6.54mm, the maximum half field angle HFOV of the optical imaging system is 50.15 °, and the f-number Fno of the optical imaging system is 1.99.

In embodiment 1, the object-side surface and the image-side surface of any one of the first lens E1 to the seventh lens E7 of the optical imaging system are aspheric, and the profile x of each aspheric lens can be defined by, but is not limited to, the following aspheric formula:

wherein x is a distance vector from the aspheric surface vertex at a position of height h of the aspheric surface along the optical axis directionHigh; 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 4 below gives the high-order term coefficients A of the respective aspherical mirror surfaces S1-S14 usable in the optical imaging system according to example 1₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆、A₁₈And A₂₀。

TABLE 2

Fig. 2A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 1, which represents the difference in the positions of images made by the lens for light of respective wavelengths. Fig. 2B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of embodiment 1. Fig. 2C shows a distortion curve of the optical imaging system of embodiment 1, which represents distortion magnitude values corresponding to different image heights. Fig. 2D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 1, which represents a deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 2A to 2D, the optical imaging system according to embodiment 1 can achieve good imaging quality.

Example two

An imaging lens according to embodiment 2 of the present application is described below with reference to fig. 3 to 4D. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic structural diagram of an optical imaging system according to embodiment 2 of the present application.

As shown in fig. 3, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

The first lens element E1 has negative power, and has a concave object-side surface S1 and a convex image-side surface S2; the second lens element E2 has positive power, and has a convex object-side surface S3 and a concave image-side surface S4; the third lens element E3 has positive power, and has a convex object-side surface S5 and a convex image-side surface S6; the fourth lens element E4 has negative power, and has a concave object-side surface S7 and a convex image-side surface S8; the fifth lens element E5 has negative power, and has a concave object-side surface S9 and a convex image-side surface S10; the sixth lens element E6 has positive power, and has a convex object-side surface S11 and a concave image-side surface S12; the seventh lens element E7 has negative power, and has a convex object-side surface S13 and a concave image-side surface S14; filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

In this embodiment, the total effective focal length f of the optical imaging system is 5.36mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 7.89mm, the half ImgH of the diagonal length of the effective pixel region on the imaging surface S17 is 6.54mm, the maximum half field angle HFOV of the optical imaging system is 50.45 °, and the f-number Fno of the optical imaging system is 1.99.

Table 3 shows a basic parameter table of the optical imaging system of example 2, in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm). Table 4 shows high-order term coefficients that can be used for each aspherical mirror surface in example 2, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 3

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

9.6452E-03

8.4842E-03

-7.3186E-03

4.8511E-03

-2.4250E-03

8.0880E-04

-1.7018E-04

2.0263E-05

-1.0347E-06

S2

1.9380E-02

1.5772E-02

-2.3513E-02

2.5085E-02

-1.7780E-02

8.0685E-03

-2.2630E-03

3.5436E-04

-2.3533E-05

S3

-2.2751E-02

2.6210E-02

-4.3095E-02

5.0654E-02

-4.0373E-02

2.0808E-02

-6.5831E-03

1.1377E-03

-7.7021E-05

S4

-3.1664E-02

8.4116E-03

-6.1857E-03

6.5401E-03

-7.1679E-03

5.5525E-03

-2.3914E-03

4.7970E-04

-1.8235E-05

S5

-1.7576E-02

-6.7068E-03

6.9548E-03

-1.2446E-02

1.2709E-02

-8.3064E-03

3.4222E-03

-8.2900E-04

9.5163E-05

S6

-1.7481E-02

-1.2124E-02

1.9217E-02

-2.7584E-02

2.4722E-02

-1.4080E-02

4.9223E-03

-9.6675E-04

8.1688E-05

S7

4.3814E-03

-3.5164E-02

2.8693E-02

-7.1867E-03

-3.8324E-03

4.5716E-03

-1.8682E-03

3.5531E-04

-2.5836E-05

S8

1.0663E-01

-1.8532E-01

1.4045E-01

-7.0143E-02

2.4500E-02

-5.7793E-03

8.6710E-04

-7.4987E-05

2.9078E-06

S9

1.4707E-01

-1.6849E-01

1.2105E-01

-6.1632E-02

2.1583E-02

-5.0490E-03

7.5060E-04

-6.4031E-05

2.3823E-06

S10

-6.9484E-02

6.4131E-02

-2.8722E-02

6.3305E-03

-5.1972E-04

-6.2941E-05

1.8632E-05

-1.5991E-06

4.7751E-08

S11

1.6936E-02

-1.4269E-02

7.5337E-04

1.4586E-03

-6.1109E-04

1.1785E-04

-1.2467E-05

7.0065E-07

-1.6396E-08

S12

4.6531E-02

-4.5823E-02

1.6784E-02

-3.7691E-03

5.4256E-04

-5.0096E-05

2.8673E-06

-9.2469E-08

1.2819E-09

S13

-9.3897E-02

9.6134E-03

-1.7507E-04

-5.1848E-05

6.2891E-06

-3.9494E-07

1.5648E-08

-3.6951E-10

3.9361E-12

S14

-1.0007E-01

2.0126E-02

-2.9121E-03

2.9079E-04

-1.9684E-05

8.8033E-07

-2.4789E-08

3.9681E-10

-2.7479E-12

TABLE 4

Fig. 4A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 2, which represents the difference in the positions of images made by the lens for light of respective wavelengths. Fig. 4B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of embodiment 2. Fig. 4C shows a distortion curve of the optical imaging system of embodiment 2, which represents distortion magnitude values corresponding to different angles of view. Fig. 4D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 2, which represents the deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 4A to 4D, the imaging lens according to embodiment 2 can achieve good imaging quality.

EXAMPLE III

An optical imaging system according to embodiment 3 of the present application is described below with reference to fig. 5 to 6D. Fig. 5 shows a schematic structural diagram of an optical imaging system according to embodiment 3 of the present application.

As shown in fig. 5, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

The first lens element E1 has positive power, and has a concave object-side surface S1 and a convex image-side surface S2; the second lens element E2 has positive power, and has a convex object-side surface S3 and a concave image-side surface S4; the third lens element E3 has positive power, and has a convex object-side surface S5 and a convex image-side surface S6; the fourth lens element E4 has negative power, and has a concave object-side surface S7 and a convex image-side surface S8; the fifth lens element E5 has positive power, and has a concave object-side surface S9 and a convex image-side surface S10; the sixth lens element E6 has positive power, and has a convex object-side surface S11 and a concave image-side surface S12; the seventh lens element E7 has negative power, and has a convex object-side surface S13 and a concave image-side surface S14; filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

In this embodiment, the total effective focal length f of the optical imaging system is 5.26mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 7.83mm, the half ImgH of the diagonal length of the effective pixel area on the imaging surface S17 is 6.39mm, the maximum half field angle HFOV of the optical imaging system is 49.45 °, and the f-number Fno of the optical imaging system is 1.99.

Table 5 shows a basic parameter table of the optical imaging system of example 3, in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm). Table 6 shows high-order term coefficients that can be used for each aspherical mirror surface in example 3, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 5

TABLE 6

Fig. 6A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 3, which represents the difference in the positions of images made by the lens for light of respective wavelengths. Fig. 6B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of embodiment 3. Fig. 6C shows a distortion curve of the optical imaging system of embodiment 3, which represents distortion magnitude values corresponding to different angles of view. Fig. 6D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 3, which represents the deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 6A to 6D, the optical imaging system according to embodiment 3 can achieve good imaging quality.

Example four

An optical imaging system according to embodiment 4 of the present application is described below with reference to fig. 7 to 8D. Fig. 7 shows a schematic structural diagram of an optical imaging system according to embodiment 4 of the present application.

As shown in fig. 7, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

The first lens element E1 has positive power, and has a concave object-side surface S1 and a convex image-side surface S2; the second lens element E2 has negative power, and has a convex object-side surface S3 and a concave image-side surface S4; the third lens element E3 has positive power, and has a convex object-side surface S5 and a convex image-side surface S6; the fourth lens element E4 has negative power, and has a concave object-side surface S7 and a convex image-side surface S8; the fifth lens element E5 has positive power, and has a concave object-side surface S9 and a convex image-side surface S10; the sixth lens element E6 has positive power, and has a convex object-side surface S11 and a concave image-side surface S12; the seventh lens element E7 has negative power, and has a convex object-side surface S13 and a concave image-side surface S14; filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

In this embodiment, the total effective focal length f of the optical imaging system is 5.02mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 7.90mm, the half ImgH of the diagonal length of the effective pixel area on the imaging surface S17 is 6.54mm, the maximum half field angle HFOV of the optical imaging system is 50.31 °, and the f-number Fno of the optical imaging system is 1.99.

Table 7 shows a basic parameter table of the optical imaging system of example 4 in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm). Table 8 shows high-order term coefficients that can be used for each aspherical mirror surface in example 4, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 7

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

3.9842E-03

2.1668E-02

-2.1948E-02

1.5922E-02

-8.1137E-03

2.7064E-03

-5.6073E-04

6.5156E-05

-3.2340E-06

S2

1.5274E-02

1.9110E-02

-1.9459E-02

1.7006E-02

-1.1029E-02

4.6131E-03

-1.1706E-03

1.5998E-04

-8.5950E-06

S3

3.6990E-02

-1.1518E-01

1.7889E-01

-1.9244E-01

1.4076E-01

-6.8814E-02

2.1433E-02

-3.8287E-03

2.9929E-04

S4

-5.1244E-02

1.2477E-02

1.9295E-02

-6.6400E-02

9.6042E-02

-8.0231E-02

3.9733E-02

-1.0784E-02

1.2416E-03

S5

-1.6603E-02

-4.0201E-03

5.6389E-04

-5.7330E-04

-1.9123E-03

3.0100E-03

-1.9493E-03

6.0621E-04

-7.1351E-05

S6

-1.4153E-02

-1.0278E-02

1.6228E-02

-2.6335E-02

2.6071E-02

-1.6427E-02

6.3711E-03

-1.3890E-03

1.3103E-04

S7

7.9365E-03

-3.0595E-02

1.6860E-02

5.5535E-03

-1.1365E-02

6.7826E-03

-2.0592E-03

3.1962E-04

-1.9842E-05

S8

7.5543E-02

-1.3190E-01

8.5313E-02

-3.4285E-02

9.5397E-03

-1.8549E-03

2.5069E-04

-2.2512E-05

1.0544E-06

S9

9.9108E-02

-1.0219E-01

6.1192E-02

-2.6173E-02

7.9931E-03

-1.6878E-03

2.3146E-04

-1.8412E-05

6.4132E-07

S10

-4.3624E-02

4.5745E-02

-1.9945E-02

3.5880E-03

1.8851E-04

-2.1426E-04

4.1153E-05

-3.5050E-06

1.1494E-07

S11

2.3975E-02

-1.6016E-02

2.7652E-05

2.0030E-03

-7.5763E-04

1.4138E-04

-1.4913E-05

8.4473E-07

-1.9873E-08

S12

5.9828E-02

-5.0112E-02

1.7345E-02

-3.7258E-03

5.2345E-04

-4.8210E-05

2.7991E-06

-9.2536E-08

1.3222E-09

S13

-8.7968E-02

4.0350E-03

1.7379E-03

-3.7674E-04

3.7492E-05

-2.1814E-06

7.6101E-08

-1.4806E-09

1.2388E-11

S14

-1.1574E-01

2.1345E-02

-2.7138E-03

2.3530E-04

-1.3756E-05

5.3192E-07

-1.3055E-08

1.8486E-10

-1.1559E-12

TABLE 8

Fig. 8A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 4, which represents the difference in the positions of images made by the lens for light of respective wavelengths. Fig. 8B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of embodiment 4. Fig. 8C shows a distortion curve of the optical imaging system of embodiment 4, which represents distortion magnitude values corresponding to different angles of view. Fig. 8D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 4, which represents the deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 8A to 8D, the optical imaging system according to embodiment 4 can achieve good imaging quality.

EXAMPLE five

An optical imaging system according to embodiment 5 of the present application is described below with reference to fig. 9 to 10D. Fig. 9 shows a schematic structural diagram of an optical imaging system according to embodiment 5 of the present application.

As shown in fig. 9, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

In this embodiment, the total effective focal length f of the optical imaging system is 5.21mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 7.70mm, the half ImgH of the diagonal length of the effective pixel region on the imaging surface S17 is 6.54mm, the maximum half field angle HFOV of the optical imaging system is 50.32 °, and the f-number Fno of the optical imaging system is 1.99.

Table 9 shows a basic parameter table of the optical imaging system of example 5 in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm). Table 10 shows high-order term coefficients that can be used for each aspherical mirror surface in example 5, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 9

Watch 10

Fig. 10A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 5, which represents the difference in the positions of images made by the lens for light of respective wavelengths. Fig. 10B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of example 5. Fig. 10C shows a distortion curve of the optical imaging system of embodiment 5, which represents distortion magnitude values corresponding to different angles of view. Fig. 10D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 5, which represents the deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 10A to 10D, the optical imaging system according to embodiment 5 can achieve good imaging quality.

EXAMPLE six

An optical imaging system according to embodiment 6 of the present application is described below with reference to fig. 11 to 12D. Fig. 11 shows a schematic configuration diagram of an optical imaging system according to embodiment 6 of the present application.

As shown in fig. 11, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

The first lens element E1 has negative power, and has a concave object-side surface S1 and a convex image-side surface S2; the second lens element E2 has positive power, and has a convex object-side surface S3 and a concave image-side surface S4; the third lens element E3 has positive power, and has a concave object-side surface S5 and a convex image-side surface S6; the fourth lens element E4 has negative power, and has a concave object-side surface S7 and a convex image-side surface S8; the fifth lens element E5 has positive power, and has a concave object-side surface S9 and a convex image-side surface S10; the sixth lens element E6 has positive power, and has a convex object-side surface S11 and a concave image-side surface S12; the seventh lens element E7 has negative power, and has a convex object-side surface S13 and a concave image-side surface S14; filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

In this embodiment, the total effective focal length f of the optical imaging system is 5.41mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 8.18mm, the half ImgH of the diagonal length of the effective pixel area on the imaging surface S17 is 6.54mm, the maximum half field angle HFOV of the optical imaging system is 50.36 °, and the f-number Fno of the optical imaging system is 1.99.

Table 11 shows a basic parameter table of the optical imaging system of example 6 in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm). Table 12 shows high-order term coefficients that can be used for each aspherical mirror surface in example 6, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

TABLE 11

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

1.4916E-02

9.9144E-04

-1.5853E-03

1.5139E-03

-1.0065E-03

4.0058E-04

-9.6103E-05

1.2752E-05

-7.1484E-07

S2

2.2317E-02

9.4673E-03

-1.8517E-02

2.0829E-02

-1.4829E-02

6.6743E-03

-1.8527E-03

2.8817E-04

-1.9084E-05

S3

-2.6878E-02

2.7931E-02

-3.8088E-02

3.6650E-02

-2.3188E-02

8.8326E-03

-1.6923E-03

4.9410E-05

2.5347E-05

S4

-3.0406E-02

1.0099E-02

-1.5544E-02

2.7498E-02

-3.4465E-02

2.7159E-02

-1.2603E-02

3.1279E-03

-3.0690E-04

S5

-1.9479E-02

-4.9809E-03

-1.3152E-03

4.2803E-03

-7.3570E-03

6.2242E-03

-2.8204E-03

6.2597E-04

-4.5260E-05

S6

-1.7925E-02

-1.1469E-02

1.6110E-02

-2.2284E-02

1.9357E-02

-1.0787E-02

3.7197E-03

-7.2670E-04

6.1449E-05

S7

8.9501E-03

-3.4801E-02

3.4980E-02

-2.1294E-02

9.4425E-03

-2.4164E-03

2.5464E-04

9.0573E-06

-2.3755E-06

S8

5.2723E-02

-9.3335E-02

6.3415E-02

-2.8994E-02

9.7475E-03

-2.2658E-03

3.3355E-04

-2.7817E-05

1.0295E-06

S9

7.6626E-02

-6.8287E-02

3.7623E-02

-1.5485E-02

4.5672E-03

-9.2284E-04

1.2018E-04

-9.0628E-06

3.0002E-07

S10

1.2172E-02

6.4074E-03

-3.2486E-03

-4.8200E-04

5.5202E-04

-1.4632E-04

1.9161E-05

-1.2741E-06

3.4233E-08

S11

1.8030E-02

-1.6984E-02

5.7802E-03

-1.4911E-03

2.5702E-04

-2.7659E-05

1.7161E-06

-5.3469E-08

5.9865E-10

S12

7.8008E-03

-1.1356E-02

3.0914E-03

-5.5505E-04

6.9681E-05

-5.9881E-06

3.3163E-07

-1.0539E-08

1.4493E-10

S13

-8.5172E-02

6.5949E-03

4.7830E-04

-1.3564E-04

1.2574E-05

-6.5813E-07

2.0669E-08

-3.6534E-10

2.8080E-12

S14

-9.5238E-02

1.7739E-02

-2.4315E-03

2.3081E-04

-1.4704E-05

6.1288E-07

-1.5985E-08

2.3652E-10

-1.5161E-12

TABLE 12

Fig. 12A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 6, which represents the difference in the positions of images made by the lens for light of the respective wavelengths. Fig. 12B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of example 6. Fig. 12C shows a distortion curve of the optical imaging system of embodiment 6, which represents distortion magnitude values corresponding to different angles of view. Fig. 12D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 6, which represents a deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 12A to 12D, the optical imaging system according to embodiment 6 can achieve good imaging quality.

EXAMPLE seven

An optical imaging system according to embodiment 7 of the present application is described below with reference to fig. 13 to 14D. Fig. 13 shows a schematic configuration diagram of an optical imaging system according to embodiment 7 of the present application.

As shown in fig. 13, the optical imaging lens, in order from an object side to an image side along an optical axis, comprises: 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 seventh lens E7, a filter E8, and an image plane S17.

In this embodiment, the total effective focal length f of the optical imaging system is 4.75mm, the distance TTL between the object-side surface S1 of the first lens E1 and the imaging surface S17 on the optical axis is 7.72mm, the half ImgH of the diagonal length of the effective pixel region on the imaging surface S17 is 6.39mm, the maximum half field angle HFOV of the optical imaging system is 55.00 °, and the f-number Fno of the optical imaging system is 1.99.

Table 13 shows a basic parameter table of the optical imaging system of example 7 in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm). Table 14 shows high-order term coefficients that can be used for each aspherical mirror surface in example 7, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

Watch 13

TABLE 14

Fig. 14A shows on-axis chromatic aberration curves of the optical imaging system of embodiment 7, which represent differences in positions of images made by the lens for light of respective wavelengths. Fig. 14B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the optical imaging system of embodiment 7. Fig. 14C shows a distortion curve of the optical imaging system of embodiment 7, which represents distortion magnitude values corresponding to different angles of view. Fig. 14D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 7, which represents the deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 14A to 14D, the optical imaging system according to embodiment 7 can achieve good imaging quality.

In summary, examples 1 to 7 each satisfy the relationship shown in table 15.

Conditional expression (A) example	1	2	3	4	5	6	7
								f/f6	0.56	0.74	0.55	0.53	0.55	0.22	0.22
tan(HFOV/2)*f(mm)	2.48	2.53	2.42	2.36	2.45	2.54	2.47
								(R13+R14)/f7	-0.39	-0.26	-0.39	-0.27	-0.36	-0.28	-0.20
ImgH/\|R7+R8\|	1.04	1.12	1.01	1.02	1.04	1.12	1.07
								R1/R2	0.90	0.83	1.01	1.30	0.88	0.82	0.98
DT31/DT21	0.92	0.93	0.91	0.93	0.93	0.93	0.85
								(T34+T67)/TTL	0.25	0.25	0.25	0.26	0.26	0.23	0.20
(CT4+CT5+CT6)/f	0.35	0.28	0.34	0.34	0.31	0.35	0.41
								\|f4/EPD\|	2.17	2.44	2.17	2.29	2.21	2.43	2.75
(R12-R11)/(R12+R11)	0.24	0.27	0.25	0.22	0.22	0.06	0.08

Watch 15

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

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. The optical imaging system comprises, in order from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens having optical power,

the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a convex surface;

the sixth lens has positive optical power;

the seventh lens has negative focal power, and the object side surface of the seventh lens is a convex surface;

wherein, the half of the diagonal length ImgH of the effective pixel area on the imaging surface of the optical imaging system satisfies that ImgH is more than 6mm and less than 7 mm; and

the total effective focal length f of the optical imaging system and the effective focal length f6 of the sixth lens meet f/f6 < 1 and are more than or equal to 0.22.

2. The optical imaging system of claim 1, wherein an effective focal length f4 of the fourth lens and an entrance pupil diameter EPD of the optical imaging system satisfy 2 < | f4/EPD | < 3.

3. The optical imaging system of claim 1, wherein the maximum effective radius DT31 of the object-side surface of the third lens and the maximum effective radius DT21 of the object-side surface of the second lens satisfy 0.5 < DT31/DT21 < 1.

4. The optical imaging system of claim 1, wherein a distance T34 between the third lens and the fourth lens on the optical axis, a distance T67 between the sixth lens and the seventh lens on the optical axis, and a distance TTL between an object side surface of the first lens and an imaging surface of the optical imaging system on the optical axis satisfy 0 < (T34+ T67)/TTL < 0.5.

5. The optical imaging system of claim 1, wherein a central thickness CT4 of the fourth lens on the optical axis, a central thickness CT5 of the fifth lens on the optical axis, a central thickness CT6 of the sixth lens on the optical axis, and a total effective focal length f of the optical imaging system satisfy 0 < (CT4+ CT5+ CT6)/f < 0.6.

6. The optical imaging system of claim 1, wherein a radius of curvature R13 of an object-side surface of the seventh lens, a radius of curvature R14 of an image-side surface of the seventh lens, and an effective focal length f7 of the seventh lens satisfy-0.5 < (R13+ R14)/f7 < 0.

7. The optical imaging system of claim 1, wherein a radius of curvature R1 of the object-side surface of the first lens and a radius of curvature R2 of the image-side surface of the first lens satisfy 0.6 < R1/R2 ≦ 1.5.

8. The optical imaging system of claim 1, wherein a radius of curvature R11 of an object-side surface of the sixth lens and a radius of curvature R12 of an image-side surface of the sixth lens satisfy 0 < (R12-R11)/(R12+ R11) < 0.5.

9. The optical imaging system of claim 1, wherein a center thickness of the i-th lens on the optical axis, CTi, satisfies CTi < 1mm, where i is 1,2,3,4,5,6, or 7.

10. The optical imaging system according to any one of claims 1 to 9, wherein ImgH which is half the diagonal length of an effective pixel area on an imaging surface of the optical imaging system, a radius of curvature R7 of an object side surface of the fourth lens, and a radius of curvature R8 of an image side surface of the fourth lens satisfy 1.01 ≦ ImgH/| R7+ R8| < 1.3.

11. The optical imaging system according to any one of claims 1 to 9, wherein half of the maximum field angle of the optical imaging system and the total effective focal length f of the optical imaging system satisfy 2mm < tan (HFOV/2) × f < 2.9 mm.

12. The optical imaging system comprises, in order from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens having optical power,

the sixth lens has positive optical power;

the curvature radius R13 of the object side surface of the seventh lens, the curvature radius R14 of the image side surface of the seventh lens and the effective focal length f7 of the seventh lens meet the condition that-0.5 < (R13+ R14)/f7 < 0.

13. The optical imaging system of claim 12, wherein an effective focal length f4 of the fourth lens and an entrance pupil diameter EPD of the optical imaging system satisfy 2 < | f4/EPD | < 3.

14. The optical imaging system of claim 12, wherein the maximum effective radius DT31 of the object-side surface of the third lens and the maximum effective radius DT21 of the object-side surface of the second lens satisfy 0.5 < DT31/DT21 < 1.

15. The optical imaging system of claim 12, wherein a distance T34 between the third lens and the fourth lens on the optical axis, a distance T67 between the sixth lens and the seventh lens on the optical axis, and a distance TTL between an object side surface of the first lens and an imaging surface of the optical imaging system on the optical axis satisfy 0 < (T34+ T67)/TTL < 0.5.

16. The optical imaging system of claim 12, wherein a central thickness CT4 of the fourth lens on the optical axis, a central thickness CT5 of the fifth lens on the optical axis, a central thickness CT6 of the sixth lens on the optical axis, and a total effective focal length f of the optical imaging system satisfy 0 < (CT4+ CT5+ CT6)/f < 0.6.

17. The optical imaging system of claim 12, wherein a radius of curvature R1 of the object-side surface of the first lens and a radius of curvature R2 of the image-side surface of the first lens satisfy 0.6 < R1/R2 ≦ 1.5.

18. The optical imaging system of claim 12, wherein a radius of curvature R11 of an object-side surface of the sixth lens and a radius of curvature R12 of an image-side surface of the sixth lens satisfy 0 < (R12-R11)/(R12+ R11) < 0.5.

19. The optical imaging system of claim 18, wherein the total effective focal length f of the optical imaging system and the effective focal length f6 of the sixth lens satisfy 0.22 ≦ f/f6 < 1.

20. The optical imaging system of claim 12, wherein a center thickness of the i-th lens on the optical axis, CTi, satisfies CTi < 1mm, where i is 1,2,3,4,5,6, or 7.

21. The optical imaging system according to claim 12, wherein ImgH which is half the diagonal length of the effective pixel region on the imaging surface of the optical imaging system, a radius of curvature R7 of the object-side surface of the fourth lens, and a radius of curvature R8 of the image-side surface of the fourth lens satisfy 1.01 ≦ ImgH/| R7+ R8| < 1.3.

22. The optical imaging system according to any one of claims 12 to 21, wherein half of the maximum field angle of the optical imaging system and the total effective focal length f of the optical imaging system satisfy 2mm < tan (HFOV/2) × f < 2.9 mm.