CN210626761U

CN210626761U - Optical imaging system

Info

Publication number: CN210626761U
Application number: CN201921394050.7U
Authority: CN
Inventors: 杨萌; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2019-08-26
Filing date: 2019-08-26
Publication date: 2020-05-26
Anticipated expiration: 2029-08-26

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 optical imaging system satisfies the following conditional expression: f/EPD is less than 1.5; f6/R11 is more than 1.5 and less than 2.5; and 3.5 ≦ CT3/CT2 < 4.5, where f is the total effective focal length of the optical imaging system, EPD is the entrance pupil diameter of the optical imaging system, f6 is the effective focal length of the sixth lens, R11 is the radius of curvature of the object-side surface of the sixth lens, CT3 is the center thickness of the third lens on the optical axis, and CT2 is the center thickness of the second lens on the optical axis.

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 products, people have higher and higher requirements for the imaging quality of portable electronic products such as mobile phones and tablet computers. Meanwhile, with the improvement of the performance and the reduction of the size of a Charge Coupled Device (CCD) and a Complementary Metal Oxide Semiconductor (CMOS) image sensor, the corresponding imaging lens also meets the requirement of high imaging quality. On the other hand, with the trend of light and thin portable electronic products such as smart phones and tablet computers, more stringent requirements are put on the miniaturization of optical imaging systems used in cooperation with the portable electronic products.

The large-aperture optical imaging system can realize clear imaging under dark and weak light, is convenient to obtain small depth of field, realizes the shooting effect of blurring the large-aperture background, and is particularly favored by people in the field of shooting.

How to satisfy the miniaturization, high imaging quality and consider the characteristic of large aperture is one of the problems to be solved urgently in the field of lens design.

SUMMERY OF THE UTILITY MODEL

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 optical imaging system can satisfy the following conditions: f/EPD < 1.5, where f is the total effective focal length of the optical imaging system and EPD is the entrance pupil diameter of the optical imaging system.

In one embodiment, the central thickness CT3 of the third lens on the optical axis and the central thickness CT2 of the second lens on the optical axis may satisfy: CT3/CT2 is more than or equal to 3.5 and less than or equal to 4.5.

In one embodiment, the effective focal length f6 of the sixth lens and the radius of curvature R11 of the object side surface of the sixth lens may satisfy: f6/R11 is more than 1.5 and less than 2.5.

In one embodiment, the distance T67 between the sixth lens and the seventh lens on the optical axis, the central thickness CT7 of the seventh lens on the optical axis, and the central thickness CT1 of the first lens on the optical axis may satisfy: 2.4 is less than or equal to (T67+ CT7)/CT1 is less than 4.6.

In one embodiment, a separation distance T34 between the third lens and the fourth lens on the optical axis and a separation distance T45 between the fourth lens and the fifth lens on the optical axis may satisfy: 2.9 < T34/T45 < 4.6.

In one embodiment, the central thickness CT6 of the sixth lens on the optical axis and the central thickness CT5 of the fifth lens on the optical axis may satisfy: 3.0 < CT6/CT5 < 5.5.

In one embodiment, the effective focal length f6 of the sixth lens, the radius of curvature R11 of the object-side surface of the sixth lens, the effective focal length f7 of the seventh lens, and the radius of curvature R12 of the image-side surface of the sixth lens may satisfy: 1.5 < | f6/R11| + | f7/R12| < 2.5.

In one embodiment, the effective focal length f5 of the fifth lens and the effective focal length f4 of the fourth lens satisfy: f5/f4 is more than 1.0 and less than 3.0.

In one embodiment, the effective focal length f7 of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens may satisfy: -2.0 < f7/R14 < -1.5.

In one embodiment, 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: 1.5 < R7/R8 < 2.5.

In one embodiment, the distance T34 between the third lens and the fourth lens on the optical axis and the central thickness CT4 of the fourth lens on the optical axis may satisfy: 2.0 < T34/CT4 < 3.0.

In one embodiment, the first lens may have a positive optical power.

In one embodiment, the refractive index N2 of the second lens, the refractive index N4 of the fourth lens, and the refractive index N5 of the fifth lens may each be greater than 1.60.

In one embodiment, the abbe number V2 of the second lens, the abbe number V4 of the fourth lens, and the abbe number V5 of the fifth lens may all be less than 25.0.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

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

fig. 2A to 2C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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 4C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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 6C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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 8C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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 10C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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 12C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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 14C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion 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.

An optical imaging system according to an exemplary embodiment of the present application may include seven lenses having optical powers, respectively, 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 along the optical axis in sequence from the object side to the image side. Any adjacent two lenses of the first lens to the seventh lens may have a spacing distance therebetween.

In an exemplary embodiment, the first lens may have a positive optical power; the second lens may have a negative optical power; the third lens may have a positive optical power; the fourth lens may have a negative optical power; the fifth lens may have a negative optical power; the sixth lens may have a positive optical power; and the seventh lens may have a negative optical power. The low-order aberration of the control system is effectively balanced by reasonably controlling the positive and negative distribution of the focal power and the light inlet quantity of each component of the system.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 3.5 ≦ CT3/CT2 < 4.5, where CT3 is the central thickness of the third lens on the optical axis, and CT2 is the central thickness of the second lens on the optical axis. The requirement that the CT3/CT2 is less than 4.5 is met, the center thicknesses of the second lens and the third lens are effectively prevented from being too thin, and the processing and assembling difficulty is reduced.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 1.5 < f6/R11 < 2.5, wherein f6 is the effective focal length of the sixth lens, and R11 is the radius of curvature of the object side surface of the sixth lens. More specifically, f6 and R11 may further satisfy: 1.5 < f6/R11 < 2.2. The requirement that f6/R11 is more than 1.5 and less than 2.5 is met, the characteristic of large aperture of the optical imaging system can be ensured, and the field curvature and the astigmatism can be effectively reduced.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 2.4 ≦ (T67+ CT7)/CT1 < 4.6, wherein T67 is an interval distance between the sixth lens and the seventh lens on the optical axis, CT7 is a central thickness of the seventh lens on the optical axis, and CT1 is a central thickness of the first lens on the optical axis. More specifically, T67, CT7, and CT1 may further satisfy: 2.4 is more than or equal to (T67+ CT7)/CT1 is less than 3.2 or 4.5 is less than (T67+ CT7)/CT1 is less than 4.6. Satisfies the requirement of more than or equal to 2.4 (T67+ CT7)/CT1 less than 4.6, and can ensure that the lens forming process meets the engineering requirement under the condition of ensuring the total length of the optical imaging system.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 2.9 < T34/T45 < 4.6, wherein T34 is the distance between the third lens and the fourth lens on the optical axis, and T45 is the distance between the fourth lens and the fifth lens on the optical axis. The requirements of T34/T45 being more than 2.9 and less than 4.6 are met, the processing, forming and assembling characteristics of each lens can be ensured, and the mass production of the lens is facilitated.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 3.0 < CT6/CT5 < 5.5, wherein CT6 is the central thickness of the sixth lens on the optical axis, and CT5 is the central thickness of the fifth lens on the optical axis. More specifically, CT6 and CT5 further satisfy: 3.3 < CT6/CT5 < 5.3. The distortion contribution quantity of the fifth lens and the distortion contribution quantity of the sixth lens can be controlled within a reasonable range, so that the distortion quantity of each field of view of the lens is below 5%, and the requirement of later software debugging is avoided.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 1.5 < | f6/R11| + | f7/R12| < 2.5, wherein f6 is the effective focal length of the sixth lens, R11 is the radius of curvature of the object-side surface of the sixth lens, f7 is the effective focal length of the seventh lens, and R12 is the radius of curvature of the image-side surface of the sixth lens. More specifically, f6, R11, f7 and R12 may further satisfy: 1.7 < | f6/R11| + | f7/R12| < 2.5. Satisfying 1.5 < | f6/R11| + | f7/R12| < 2.5, can effectively correct field curvature, ensure tolerance stability of an optical imaging system and improve imaging quality.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 1.0 < f5/f4 < 3.0, wherein f5 is the effective focal length of the fifth lens and f4 is the effective focal length of the fourth lens. More specifically, f5 and f4 may further satisfy: f5/f4 is more than 1.4 and less than 2.4 or f5/f4 is more than 2.8 and less than 3.0. Satisfying 1.0 < f5/f4 < 3.0, reducing the deflection angle of the incident light and improving the imaging quality of the optical imaging system.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: -2.0 < f7/R14 < -1.5, wherein f7 is the effective focal length of the seventh lens and R14 is the radius of curvature of the image-side surface of the seventh lens. More specifically, f7 and R14 may further satisfy: -2.0 < f7/R14 < -1.7. Satisfying-2.0 < f7/R14 < -1.5, the curvature radius of the image side surface of the seventh lens is ensured to be positive under the condition that the optical power of the seventh lens is negative, namely, the image side surface is concave, so that the astigmatism of the optical imaging system can be effectively balanced, and the miniaturization of the optical system is further ensured.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 1.5 < R7/R8 < 2.5, wherein R7 is the radius of curvature of the object-side surface of the fourth lens, and R8 is the radius of curvature of the image-side surface of the fourth lens. More specifically, R7 and R8 may further satisfy: 1.5 < R7/R8 < 2.4. Satisfying 1.5 < R7/R8 < 2.5 helps to improve the spherical aberration and astigmatism of the optical imaging system.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: 2.0 < T34/CT4 < 3.0, wherein T34 is the distance between the third lens and the fourth lens on the optical axis, and CT4 is the central thickness of the fourth lens on the optical axis. More specifically, T34 and CT4 further satisfy: 2.1 < T34/CT4 < 2.9. The requirement that T34/CT4 is more than 2.0 and less than 3.0 is met, the field curvature and distortion of the optical imaging system can be effectively ensured, and therefore the off-axis field of view of the optical imaging system has good imaging quality.

In an exemplary embodiment, the refractive index N2 of the second lens, the refractive index N4 of the fourth lens, and the refractive index N5 of the fifth lens may each be greater than 1.60. The lens made of the high-refractive-index material is beneficial to correcting off-axis coma aberration and astigmatism of the optical imaging system and improving the quality of an external view field image of the optical imaging system.

In an exemplary embodiment, the abbe number V2 of the second lens, the abbe number V4 of the fourth lens, and the abbe number V5 of the fifth lens may each be less than 25.0. The lens made of the material with the lower Abbe number is favorable for correcting off-axis coma aberration and astigmatism of the optical imaging system, and the quality of an external view field image of the optical imaging system is improved.

In an exemplary embodiment, the optical imaging system according to the present application further includes a stop disposed between the third lens and the fourth 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.

In an exemplary embodiment, an optical imaging system according to the present application may satisfy: f/EPD < 1.5, where f is the total effective focal length of the optical imaging system and EPD is the entrance pupil diameter of the optical imaging system. The f/EPD is less than 1.5, so that the optical imaging system has a larger aperture and the integral brightness of imaging is improved.

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. Through the configuration, the application provides a seven-piece optical imaging system which is applicable to portable electronic products, has a large aperture and good imaging quality.

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 1

An optical imaging system according to embodiment 1 of the present application is described below with reference to fig. 1 to 2C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

The first lens element E1 has positive power, and has a convex object-side surface S1 and a concave 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 convex object-side surface S7 and a concave image-side surface S8. The fifth lens element E5 has negative power, and has a convex object-side surface S9 and a concave 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 concave 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/distance, and the focal length are all millimeters (mm).

TABLE 1

In the present example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system (i.e., the distance on the optical axis from the object-side surface S1 of the first lens E1 to the imaging surface S17 of the optical imaging system) is 5.40mm, the half ImgH of the diagonal length of the effective pixel region on the imaging surface S17 of the optical imaging system is 3.26mm, and the maximum half field angle Semi-FOV of the optical imaging system is 39.0 °.

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

wherein x is the distance from the aspheric surface to the aspheric surface top when the aspheric surface is at the position with the height h along the optical axis directionDistance rise of points; 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 shows the high-order coefficient A of each of the aspherical mirror surfaces S1 to S14 used in 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 deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. 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 angles of view. As can be seen from fig. 2A to 2C, the optical imaging system according to embodiment 1 can achieve good imaging quality.

Example 2

An optical imaging system according to embodiment 2 of the present application is described below with reference to fig. 3 to 4C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

The first lens element E1 has positive power, and has a convex object-side surface S1 and a concave 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 convex object-side surface S7 and a concave image-side surface S8. The fifth lens element E5 has negative power, and has a convex object-side surface S9 and a concave 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 example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system is 5.49mm, the half ImgH of the diagonal length of the effective pixel area on the imaging plane S17 of the optical imaging system is 3.24mm, and the maximum half field angle Semi-FOV of the optical imaging system is 39.0 °.

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/distance, 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

-2.3213E-01

-4.2561E-02

3.6983E-02

4.3225E-03

-3.8600E-03

8.4964E-04

1.4115E-03

-3.2486E-05

-3.4113E-04

S2

9.8671E-02

-2.7193E-02

1.0563E-02

-3.0841E-03

-6.9247E-04

-4.2185E-04

6.0452E-04

2.9937E-04

2.5862E-05

S3

-1.2049E-01

3.0727E-02

-1.7061E-02

-7.6994E-03

1.8305E-03

-1.0294E-03

-8.6136E-04

1.9858E-04

-1.6126E-05

S4

-9.2694E-02

3.5096E-02

-1.7906E-02

-8.5404E-03

6.7100E-03

3.8443E-04

-2.9987E-03

1.7642E-04

6.6570E-04

S5

3.0354E-01

2.4958E-02

-6.2878E-03

-4.7602E-03

5.5689E-03

2.2904E-03

-1.9946E-03

-1.8178E-04

3.5441E-04

S6

-1.0564E-03

1.7575E-03

5.1418E-04

3.0592E-04

2.8844E-04

1.1680E-04

4.0351E-06

-6.6645E-05

2.1327E-06

S7

-1.9508E-01

1.9929E-02

-3.7114E-03

-2.3323E-03

-9.9496E-04

-6.9600E-04

-2.4333E-04

-8.6701E-05

-8.1567E-05

S8

-3.3365E-01

3.1547E-02

-1.1536E-03

-5.1215E-03

-1.0318E-03

-1.0756E-03

-3.2050E-04

-2.1898E-04

-8.1339E-05

S9

-1.4037E-01

-5.0494E-02

-2.2882E-03

-3.9008E-03

-2.3124E-03

5.5367E-05

-3.2008E-04

-6.3476E-05

-1.8454E-04

S10

-3.6857E-01

-7.9885E-03

-2.6771E-02

-7.5999E-03

-1.1063E-02

-2.5039E-03

-3.0160E-03

-1.0896E-03

-5.4391E-04

S11

-8.7644E-02

-3.7761E-02

-5.0398E-03

-1.1147E-02

7.6687E-04

9.1554E-04

5.7057E-04

-5.2329E-05

2.4463E-05

S12

-5.0328E-01

-6.2792E-02

2.8408E-02

1.0285E-02

-1.3946E-03

-3.3577E-03

-1.4609E-03

-2.6451E-04

1.8880E-04

S13

-1.7731E+00

5.8235E-01

-1.8138E-02

1.8559E-03

-3.2055E-02

6.9002E-04

3.8049E-03

1.8514E-03

-9.7832E-04

S14

-1.5386E+00

3.0446E-01

-5.7453E-03

3.0045E-02

-1.8024E-02

9.4149E-04

-1.3589E-03

1.0235E-03

-1.5230E-04

TABLE 4

Fig. 4A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 2, which represents the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. 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. As can be seen from fig. 4A to 4C, the optical imaging system according to embodiment 2 can achieve good imaging quality.

Example 3

An optical imaging system according to embodiment 3 of the present application is described below with reference to fig. 5 to 6C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

In this example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system is 5.49mm, the half ImgH of the diagonal length of the effective pixel area on the imaging plane S17 of the optical imaging system is 3.34mm, and the maximum half field angle Semi-FOV of the optical imaging system is 39.0 °.

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/distance, 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

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-2.1010E-01

-4.4273E-02

3.0203E-02

4.8797E-03

-2.7209E-03

6.5693E-04

9.1720E-04

-1.3317E-05

-2.9812E-04

S2

9.3556E-02

-2.4675E-02

8.4859E-03

-2.4147E-03

1.7098E-04

-1.9083E-04

5.2506E-05

1.5612E-04

-4.2381E-05

S3

-1.2243E-01

2.8237E-02

-1.7082E-02

-7.4350E-03

1.3145E-03

-1.3951E-03

-1.1706E-03

1.4944E-04

-6.2753E-05

S4

-1.0204E-01

3.4434E-02

-1.8835E-02

-4.4481E-03

6.5435E-03

-1.0095E-03

-2.7418E-03

6.6203E-04

7.4353E-04

S5

2.8484E-01

2.4959E-02

-6.4476E-03

-2.9210E-03

5.1834E-03

2.0960E-03

-1.3484E-03

-1.3465E-04

2.5737E-04

S6

7.9899E-04

2.1172E-03

1.9555E-04

1.3959E-04

2.6863E-04

1.3764E-04

1.5054E-05

-6.4282E-05

-2.1235E-07

S7

-1.9767E-01

1.9465E-02

-4.4060E-03

-3.4953E-03

-1.7536E-03

-1.2448E-03

-5.5403E-04

-2.5375E-04

-9.9051E-05

S8

-3.2965E-01

2.7536E-02

-4.4278E-03

-8.2760E-03

-3.3830E-03

-2.2478E-03

-7.4977E-04

-2.8737E-04

-2.7112E-05

S9

-1.6046E-01

-5.3165E-02

-5.4538E-03

-4.2200E-03

-2.9978E-03

-2.1109E-04

-4.5198E-04

-1.1665E-04

-1.6082E-04

S10

-3.0769E-01

-6.9074E-04

-2.5554E-02

-5.5796E-03

-1.0091E-02

-1.5425E-03

-2.1382E-03

-5.8520E-04

-3.8479E-04

S11

-1.4078E-01

-5.1850E-02

-8.6408E-03

-1.2853E-02

6.8232E-03

4.7657E-03

3.5413E-03

1.4796E-03

6.8136E-04

S12

-4.4109E-01

-4.4444E-02

3.7148E-02

4.0476E-03

-6.2492E-03

-5.4258E-03

-2.0744E-03

-2.0641E-04

2.0713E-04

S13

-1.8891E+00

6.7489E-01

-3.6880E-02

-3.2417E-02

-4.1156E-02

8.3613E-03

4.2243E-03

-2.7335E-03

-4.4164E-03

S14

-1.9961E+00

1.2835E+00

1.8430E-01

3.0745E-01

1.7502E-01

2.1452E-03

-1.4868E-01

-9.8842E-02

-2.9279E-02

TABLE 6

Fig. 6A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 3, which represents the convergent focus deviation of light rays of different wavelengths after passing through the lens. 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. As can be seen from fig. 6A to 6C, the optical imaging system according to embodiment 3 can achieve good imaging quality.

Example 4

An optical imaging system according to embodiment 4 of the present application is described below with reference to fig. 7 to 8C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

In this example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system is 5.48mm, the half ImgH of the diagonal length of the effective pixel area on the imaging plane S17 of the optical imaging system is 3.30mm, and the maximum half field angle Semi-FOV of the optical imaging system is 39.0 °.

Table 7 shows a basic parameter table of the optical imaging system of example 4 in which the units of the radius of curvature, thickness/distance, and 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

TABLE 8

Fig. 8A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 4, which represents the convergent focus deviation of light rays of different wavelengths after passing through the lens. 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. As can be seen from fig. 8A to 8C, the optical imaging system according to embodiment 4 can achieve good imaging quality.

Example 5

An optical imaging system according to embodiment 5 of the present application is described below with reference to fig. 9 to 10C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

The first lens element E1 has positive power, and has a convex object-side surface S1 and a concave 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 convex object-side surface S7 and a concave image-side surface S8. The fifth lens element E5 has negative power, and has a convex object-side surface S9 and a concave image-side surface S10. The sixth lens element E6 has positive power, and has a convex object-side surface S11 and a convex 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 example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system is 5.48mm, the half ImgH of the diagonal length of the effective pixel area on the imaging plane S17 of the optical imaging system is 3.33mm, and the maximum half field angle Semi-FOV of the optical imaging system is 40.0 °.

Table 9 shows a basic parameter table of the optical imaging system of example 5 in which the units of the radius of curvature, thickness/distance, and 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

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S1

-1.6695E-01

-3.3450E-02

2.3521E-02

3.3662E-03

-2.5352E-03

-2.6162E-04

8.5085E-04

3.5754E-04

-2.2167E-04

S2

9.3544E-02

-2.0298E-02

8.4345E-03

-1.2884E-03

2.6384E-04

-1.7758E-03

8.6819E-04

-2.8818E-05

4.8733E-05

S3

-1.2940E-01

1.8545E-02

-8.6835E-03

-3.0351E-03

3.9488E-03

-1.7901E-03

3.7574E-04

-2.3963E-04

3.9212E-05

S4

-1.0056E-01

2.1676E-02

-1.5848E-02

-3.7361E-03

7.0404E-03

-7.2509E-04

-8.4393E-04

-3.7587E-05

1.4717E-04

S5

2.4465E-01

2.3847E-02

-1.0562E-02

-5.0536E-03

3.0753E-03

6.8794E-04

-5.6946E-04

1.1444E-06

8.0758E-06

S6

6.7157E-03

1.8919E-03

-8.1402E-04

-5.6441E-04

4.9531E-05

7.8986E-05

4.3346E-05

-5.5895E-05

-3.9781E-06

S7

-1.7586E-01

8.3375E-03

-1.6084E-03

-1.6369E-03

-7.0706E-04

-4.6227E-04

-2.1519E-04

-4.2819E-05

-1.1008E-04

S8

-2.7669E-01

1.1110E-02

5.1213E-03

-4.7186E-03

-1.3544E-03

-7.8242E-04

2.3808E-04

6.1707E-05

-3.7030E-05

S9

-9.2095E-02

-3.1475E-02

-3.3578E-03

-7.0957E-03

-4.6327E-03

-1.3838E-03

-1.8137E-04

2.5221E-05

-1.4150E-04

S10

-2.3900E-01

5.4193E-03

-2.4906E-02

-4.6825E-03

-4.7074E-03

3.3043E-04

1.2136E-04

2.2098E-06

-1.8155E-04

S11

-1.1622E-01

-3.5784E-02

-1.1066E-02

-4.7024E-03

2.5545E-03

2.5827E-03

1.1561E-03

3.4273E-04

-4.1863E-05

S12

-3.1329E-01

-6.1219E-02

1.9615E-02

-1.0212E-03

-2.2231E-03

-7.5243E-04

1.3223E-03

9.5471E-04

5.9430E-04

S13

-1.8298E+00

5.9663E-01

-4.7244E-02

8.4366E-04

-2.4408E-02

5.2490E-03

3.1945E-03

1.2368E-03

-1.2702E-03

S14

-1.7406E+00

4.5892E-01

-2.4413E-02

1.3485E-02

-2.8881E-02

3.5476E-03

4.1034E-04

6.3352E-04

-4.7944E-04

Watch 10

Fig. 10A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 5, which represents the convergent focus deviation of light rays of different wavelengths after passing through the lens. 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. As can be seen from fig. 10A to 10C, the optical imaging system according to embodiment 5 can achieve good imaging quality.

Example 6

An optical imaging system according to embodiment 6 of the present application is described below with reference to fig. 11 to 12C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

The first lens element E1 has positive power, and has a convex object-side surface S1 and a concave 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 concave image-side surface S6. The fourth lens element E4 has negative power, and has a convex object-side surface S7 and a concave image-side surface S8. The fifth lens element E5 has negative power, and has a convex object-side surface S9 and a concave 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 example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system is 5.37mm, the half ImgH of the diagonal length of the effective pixel area on the imaging plane S17 of the optical imaging system is 3.29mm, and the maximum half field angle Semi-FOV of the optical imaging system is 40.0 °.

Table 11 shows a basic parameter table of the optical imaging system of example 6 in which the units of the radius of curvature, thickness/distance, and 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

-1.6583E-01

-3.2090E-02

2.5908E-02

3.1904E-03

-2.5017E-03

1.3987E-04

9.4172E-04

1.4955E-04

-2.9747E-04

S2

9.1197E-02

-2.0605E-02

9.0087E-03

-1.6553E-03

1.0051E-04

-1.2694E-03

9.2097E-04

-1.8676E-04

-1.4802E-05

S3

-1.3157E-01

1.8393E-02

-9.3582E-03

-2.7852E-03

3.7524E-03

-1.7259E-03

3.1226E-04

-2.3733E-04

4.1631E-06

S4

-9.8216E-02

2.1372E-02

-1.5491E-02

-2.8751E-03

6.8173E-03

-9.0236E-04

-9.0610E-04

8.4571E-05

1.6587E-04

S5

2.5096E-01

2.4161E-02

-1.1110E-02

-4.9059E-03

2.7812E-03

2.9539E-04

-8.1540E-04

-4.0250E-05

-6.3754E-06

S6

7.7772E-03

1.8511E-03

-1.1239E-03

-6.3910E-04

-4.9417E-05

5.6740E-05

1.3704E-05

-5.3939E-05

-6.9634E-06

S7

-1.7750E-01

6.6062E-03

-1.7763E-03

-2.4949E-03

-9.7747E-04

-8.0859E-04

-3.4483E-04

-1.2761E-04

-9.5173E-05

S8

-2.7832E-01

1.2626E-02

5.2696E-03

-6.0205E-03

-1.2971E-03

-9.6950E-04

1.7532E-04

5.2560E-05

2.5103E-05

S9

-9.1327E-02

-3.1602E-02

-3.4129E-03

-7.8035E-03

-3.7967E-03

-9.1310E-04

-1.8137E-04

2.5220E-05

-5.9509E-05

S10

-2.5116E-01

7.2804E-03

-2.6127E-02

-4.6434E-03

-4.6897E-03

5.1430E-04

2.9700E-05

1.4095E-04

-5.1556E-05

S11

-1.0645E-01

-3.7217E-02

-1.0927E-02

-7.4157E-03

2.0328E-03

2.6088E-03

1.2742E-03

5.4084E-04

7.4842E-05

S12

-3.0398E-01

-6.2742E-02

2.1399E-02

6.4710E-04

-1.0017E-03

8.8568E-05

1.0340E-03

7.1303E-04

3.7540E-04

S13

-1.8095E+00

6.0473E-01

-4.6038E-02

-1.1819E-03

-2.3121E-02

6.0144E-03

1.8935E-03

5.1914E-04

-7.2413E-04

S14

-1.7269E+00

4.6676E-01

-2.7899E-02

1.2844E-02

-3.2005E-02

6.0831E-03

1.7877E-04

8.4577E-04

-6.8143E-04

TABLE 12

Fig. 12A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 6, which represents the convergent focus deviation of light rays of different wavelengths after passing through the lens. 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. As can be seen from fig. 12A to 12C, the optical imaging system according to embodiment 6 can achieve good imaging quality.

Example 7

An optical imaging system according to embodiment 7 of the present application is described below with reference to fig. 13 to 14C. 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 system, in order from an object side to an image side, comprises: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an image forming surface S17.

The first lens element E1 has positive power, and has a convex object-side surface S1 and a concave 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 convex object-side surface S7 and a concave image-side surface S8. The fifth lens element E5 has negative power, and has a convex object-side surface S9 and a concave image-side surface S10. The sixth lens element E6 has positive power, and has a convex object-side surface S11 and a convex image-side surface S12. The seventh lens element E7 has negative power, and has a concave 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 example, the total effective focal length f of the optical imaging system is 4.00mm, the total length TTL of the optical imaging system is 5.62mm, the half ImgH of the diagonal length of the effective pixel area on the imaging plane S17 of the optical imaging system is 3.28mm, and the maximum half field angle Semi-FOV of the optical imaging system is 40.0 °.

Table 13 shows a basic parameter table of the optical imaging system of example 7 in which the units of the radius of curvature, thickness/distance, and 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 an on-axis chromatic aberration curve of the optical imaging system of embodiment 7, which represents the convergent focus deviation of light rays of different wavelengths after passing through the lens. 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. As can be seen from fig. 14A to 14C, 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.

Conditions/examples	1	2	3	4	5	6	7
								f/EPD	1.37	1.39	1.41	1.43	1.45	1.47	1.5
CT3/CT2	3.50	3.96	3.75	3.66	3.61	3.5	4.22
								f6/R11	2.12	2.12	2.09	2.03	1.75	1.93	1.57
(T67+CT7)/CT1	2.43	2.68	3.02	3.06	3.14	3.01	4.52
								T34/T45	2.94	3.43	2.93	3.87	4.55	4.11	4.02
CT6/CT5	3.37	4.05	3.47	3.50	3.87	3.50	5.28
								\|f6/R11\|+\|f7/R12\|	2.40	2.38	2.37	2.23	1.83	2.02	1.85
f5/f4	1.62	2.91	1.48	1.89	1.89	1.63	2.31
								f7/R14	-1.82	-1.86	-1.93	-1.91	-1.95	-1.97	-1.72
R7/R8	1.93	2.13	2.04	1.88	1.57	1.57	2.30
								T34/CT4	2.26	2.44	2.37	2.40	2.49	2.31	2.83

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 optical imaging system satisfies the following conditional expression:

f/EPD＜1.5；

f6/R11 is more than 1.5 and less than 2.5; and

3.5≤CT3/CT2＜4.5；

wherein f is a total effective focal length of the optical imaging system, EPD is an entrance pupil diameter of the optical imaging system, f6 is an effective focal length of the sixth lens, R11 is a radius of curvature of an object-side surface of the sixth lens, CT3 is a center thickness of the third lens on the optical axis, and CT2 is a center thickness of the second lens on the optical axis.

2. The optical imaging system according to claim 1, wherein a separation distance T67 between the sixth lens and the seventh lens on the optical axis, a central thickness CT7 of the seventh lens on the optical axis, and a central thickness CT1 of the first lens on the optical axis satisfy: 2.4 is less than or equal to (T67+ CT7)/CT1 is less than 4.6.

3. The optical imaging system of claim 1, wherein a separation distance T34 between the third lens and the fourth lens on the optical axis and a separation distance T45 between the fourth lens and the fifth lens on the optical axis satisfy: 2.9 < T34/T45 < 4.6.

4. The optical imaging system of claim 1, wherein a center thickness CT6 of the sixth lens on the optical axis and a center thickness CT5 of the fifth lens on the optical axis satisfy: 3.0 < CT6/CT5 < 5.5.

5. The optical imaging system of claim 1, wherein an effective focal length f6 of the sixth lens, a radius of curvature R11 of an object-side surface of the sixth lens, an effective focal length f7 of the seventh lens, and a radius of curvature R12 of an image-side surface of the sixth lens satisfy: 1.5 < | f6/R11| + | f7/R12| < 2.5.

6. The optical imaging system of claim 1, wherein the effective focal length f5 of the fifth lens and the effective focal length f4 of the fourth lens satisfy: f5/f4 is more than 1.0 and less than 3.0.

7. The optical imaging system of claim 1, wherein an effective focal length f7 of the seventh lens and a radius of curvature R14 of an image side surface of the seventh lens satisfy: -2.0 < f7/R14 < -1.5.

8. The optical imaging system of claim 1, wherein 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 satisfy: 1.5 < R7/R8 < 2.5.

9. The optical imaging system of claim 1, wherein the third lens and the fourth lens are separated by a distance T34 on the optical axis and a center thickness CT4 of the fourth lens on the optical axis, such that: 2.0 < T34/CT4 < 3.0.

10. The optical imaging system of claim 1, wherein the first lens has a positive optical power.

11. The optical imaging system of any one of claims 1 to 10, wherein a refractive index N2 of the second lens, a refractive index N4 of the fourth lens, and a refractive index N5 of the fifth lens are each greater than 1.60.

12. The optical imaging system according to any one of claims 1 to 10, characterized in that an abbe number V2 of the second lens, an abbe number V4 of the fourth lens and an abbe number V5 of the fifth lens are all smaller than 25.0.

13. 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 optical imaging system satisfies the following conditional expression:

f/EPD＜1.5；

f6/R11 is more than 1.5 and less than 2.5; and

2.4≤(T67+CT7)/CT1＜4.6；

wherein f is a total effective focal length of the optical imaging system, EPD is an entrance pupil diameter of the optical imaging system, f6 is an effective focal length of the sixth lens, R11 is a radius of curvature of an object side surface of the sixth lens, T67 is a separation distance of the sixth lens and the seventh lens on the optical axis, CT7 is a center thickness of the seventh lens on the optical axis and CT1 is a center thickness of the first lens on the optical axis.

14. The optical imaging system of claim 13, wherein the optical axis separation distance T34 between the third lens and the fourth lens and the optical axis separation distance T45 between the fourth lens and the fifth lens satisfies: 2.9 < T34/T45 < 4.6.

15. The optical imaging system of claim 13, wherein a center thickness CT6 of the sixth lens on the optical axis and a center thickness CT5 of the fifth lens on the optical axis satisfy: 3.0 < CT6/CT5 < 5.5.

16. The optical imaging system of claim 15, wherein a center thickness CT3 of the third lens on the optical axis and a center thickness CT2 of the second lens on the optical axis satisfy: CT3/CT2 is more than or equal to 3.5 and less than or equal to 4.5.

17. The optical imaging system of claim 13, wherein an effective focal length f6 of the sixth lens, a radius of curvature R11 of an object-side surface of the sixth lens, an effective focal length f7 of the seventh lens, and a radius of curvature R12 of an image-side surface of the sixth lens satisfy: 1.5 < | f6/R11| + | f7/R12| < 2.5.

18. The optical imaging system of claim 13, wherein the effective focal length f5 of the fifth lens and the effective focal length f4 of the fourth lens satisfy: f5/f4 is more than 1.0 and less than 3.0.

19. The optical imaging system of claim 13, wherein an effective focal length f7 of the seventh lens and a radius of curvature R14 of an image side surface of the seventh lens satisfy: -2.0 < f7/R14 < -1.5.

20. The optical imaging system of claim 13, wherein 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 satisfy: 1.5 < R7/R8 < 2.5.

21. The optical imaging system of claim 13, wherein the third lens and the fourth lens are separated by a distance T34 on the optical axis and a center thickness CT4 of the fourth lens on the optical axis, such that: 2.0 < T34/CT4 < 3.0.

22. The optical imaging system of claim 13, wherein the first lens has a positive optical power.

23. The optical imaging system of any of claims 13 to 22, wherein the refractive index N2 of the second lens, the refractive index N4 of the fourth lens, and the refractive index N5 of the fifth lens are each greater than 1.60.

24. The optical imaging system according to any one of claims 13 to 22, wherein an abbe number V2 of the second lens, an abbe number V4 of the fourth lens and an abbe number V5 of the fifth lens are all smaller than 25.0.