CN114063254A

CN114063254A - Optical imaging system

Info

Publication number: CN114063254A
Application number: CN202111461017.3A
Authority: CN
Inventors: 闻人建科
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2017-06-02
Filing date: 2017-06-02
Publication date: 2022-02-18
Anticipated expiration: 2037-06-02
Also published as: CN106990510A; CN106990510B; CN114063254B

Abstract

The application discloses an optical imaging system, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens from an object side to an image side along an optical axis. The first lens has negative focal power, and the image side surface of the first lens is a concave surface; the fourth lens has positive focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens has positive focal power or negative focal power, and the image side surface of the fifth lens is a concave surface; the seventh lens has positive focal power or negative focal power; the second lens, the third lens and the sixth lens respectively have positive focal power or negative focal power; and the effective radius DT11 of the object side surface of the first lens and the effective radius DT72 of the image side surface of the seventh lens meet the following conditions: 0.7< DT11/DT72< 1.3.

Description

Optical imaging system

Divisional application statement

The application is a divisional application of a Chinese patent application with the invention name of 'optical imaging system' and the application number of 201710408244.7 filed on 6/2/2017.

Technical Field

The present invention relates to an optical imaging system, and more particularly, to a wide-angle imaging lens composed of seven lenses.

Background

With the development of science and technology, wide-angle lenses can be applied to more and more occasions, and are more and more favored by various manufacturers and customers due to the unique performance of the wide-angle lenses compared with the common lenses. The wide-angle lens has short focal length and long depth of field, can ensure that the front scenery and the rear scenery of a shot main body can be clearly reproduced on the picture, and is very favorable for shooting; the wide-angle lens also has the characteristic of a large field angle, and can acquire more information under the same condition, so that the wide-angle lens is an important application characteristic in the fields of security lenses, vehicle-mounted lenses and the like.

At present, a general wide-angle lens mainly adopts an all-glass structure, has a long total length and general imaging quality; due to the increasing development of portable electronic products, especially the increasing 360-degree around-the-eye application in the current market, further higher requirements are put forward on the performances of miniaturization, light weight, super-wide angle, imaging quality and the like of the camera lens. In order to satisfy the requirements of miniaturization and light weight, it is necessary to further shorten the overall length of the lens and, at the same time, to incorporate a plastic lens. The total length of the system is shortened, and the field angle is enlarged. Generally, the aspheric surface can not only significantly improve the image quality and reduce the aberration, but also reduce the number of lenses of the lens and reduce the volume. The aspheric lens is made of glass or plastic, and the aspheric lens made of glass is divided into two methods of grinding and die-casting. The use of the aspheric surface greatly helps to improve the performance of the ultra-wide angle lens.

The invention aims to provide a seven-piece wide-angle lens which is miniaturized, has high imaging quality and adopts an aspheric surface.

Disclosure of Invention

The technical solution provided by the present application at least partially solves the technical problems described above.

According to an aspect of the present application, there is provided an optical imaging system including, in order from an object side to an image side along an optical axis, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, and a seventh lens element. The first lens has negative focal power, and the image side surface of the first lens is a concave surface; the fourth lens has positive focal power; the fifth lens has positive focal power or negative focal power, and the image side surface of the fifth lens is a concave surface; the seventh lens has positive focal power or negative focal power, the image side surface of the seventh lens is an aspheric surface, and at least one inflection point is formed; the second lens, the third lens and the sixth lens respectively have positive focal power or negative focal power; and the effective radius DT11 of the object side surface of the first lens and the effective radius DT72 of the image side surface of the seventh lens can satisfy the following conditions: 0.7< DT11/DT72<1.3, e.g., 0.87 ≦ DT11/DT72 ≦ 1.16.

In one embodiment, the effective radius DT11 of the object side surface of the first lens and the half ImgH of the diagonal length of the effective pixel area of the electronic photosensitive element of the optical imaging system satisfy: 0.5< DT11/ImgH <1, e.g., 0.71 ≦ DT11/ImgH ≦ 0.87.

In one embodiment, a distance T12 between the first lens and the second lens on the optical axis and a distance T67 between the sixth lens and the seventh lens on the optical axis may satisfy: 0.9< T12/T67<2.7, e.g., 0.94. ltoreq. T12/T67. ltoreq.2.64.

In one embodiment, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: -1.7< f1/f4< -1.1, for example, -1.52. ltoreq. f1/f 4. ltoreq.1.44.

In one embodiment, the central thickness CT3 of the third lens on the optical axis and the central thickness CT6 of the sixth lens on the optical axis and the distance TTL between the object-side surface of the first lens and the imaging surface of the optical imaging system on the optical axis can satisfy: (CT3+ CT6)/TTL <0.15, e.g., (CT3+ CT6)/TTL < 0.13.

In one embodiment, 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 and an aperture value of the optical imaging system may satisfy: TTL/Fno <2.2(mm), for example, TTL/Fno ≦ 2.1.

In one embodiment, ImgH, which is half the diagonal length of the effective pixel area of the electronic photosensitive element of the optical imaging system, and the effective focal length f of the optical imaging lens of the optical imaging system satisfy: ImgH/f >1, for example, ImgH/f.gtoreq.1.21.

In one embodiment, the central thickness CT2 of the second lens on the optical axis and the central thickness CT3 of the third lens on the optical axis may satisfy: 0.9< CT2/CT3<2.5, e.g., 0.93 ≦ CT2/CT3 ≦ 2.42.

In one embodiment, a center thickness sum Σ CT on the optical axis of the first lens to the seventh lens 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: sigma CT/TTL <0.6, e.g., Sigma CT/TTL ≦ 0.5.

In one embodiment, 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 may satisfy: -1.6< R7/R8< -0.5, for example, -1.57. ltoreq. R7/R8. ltoreq. 0.61.

By the optical imaging system configured as above, at least one of the advantages of miniaturization, ultra wide angle, high imaging quality, high definition, low sensitivity, balanced aberration, and the like can be further achieved.

Drawings

The above and other advantages of embodiments of the present application will become apparent from the detailed description made with reference to the following drawings, which are intended to illustrate and not to limit exemplary embodiments of the present application. In the drawings:

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

fig. 2A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 1;

fig. 2B shows an astigmatism curve of the optical imaging system of embodiment 1;

fig. 2C shows a distortion curve of the optical imaging system of embodiment 1;

fig. 2D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 1;

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

fig. 4A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 2;

fig. 4B shows an astigmatism curve of the optical imaging system of embodiment 2;

fig. 4C shows a distortion curve of the optical imaging system of embodiment 2;

fig. 4D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 2;

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

fig. 6A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 3;

fig. 6B shows an astigmatism curve of the optical imaging system of embodiment 3;

fig. 6C shows a distortion curve of the optical imaging system of embodiment 3;

fig. 6D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 3;

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

fig. 8A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 4;

fig. 8B shows an astigmatism curve of the optical imaging system of embodiment 4;

fig. 8C shows a distortion curve of the optical imaging system of embodiment 4;

fig. 8D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 4;

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

fig. 10A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 5;

FIG. 10B shows an astigmatism curve of the optical imaging system of example 5;

fig. 10C shows a distortion curve of the optical imaging system of embodiment 5;

fig. 10D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 5.

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 the expressions first, second, etc. in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation on the features. Thus, the first lens discussed below may also be referred to as the second 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.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "including," and/or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, 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.

As used herein, the terms "substantially," "about," and the like are used as terms of table approximation and not as terms of table degree, and are intended to account for inherent deviations in measured or calculated values that will be recognized by those of ordinary skill in the art.

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.

The paraxial region refers to a region near the optical axis. The first lens is the lens closest to the object and the seventh lens is the lens closest to the light sensing element. Herein, a surface closest to the object in each lens is referred to as an object side surface, and a surface closest to the imaging surface in each lens is referred to as an image side surface.

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 present application is further described below with reference to specific examples.

The optical imaging system according to the exemplary embodiment of the present application has, for example, seven lenses, 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 order from the object side to the image side along the optical axis.

In an exemplary embodiment, the first lens may have a negative optical power, the image side surface of which is concave; the fourth lens may have a positive optical power. The fifth lens can have positive power or negative power, and the image side surface of the fifth lens is concave. The seventh lens element has positive or negative power, and has an aspheric image-side surface and at least one inflection point. Alternatively, the second lens, the third lens, and the sixth lens may have positive power or negative power, respectively. Through the reasonable positive and negative distribution of the focal power of each lens in the control system, the low-order aberration of the control system can be effectively balanced, so that the system can obtain better imaging quality.

In an exemplary embodiment, the effective radius DT11 of the object side surface of the first lens and the half ImgH of the diagonal length of the effective pixel area of the electronic photosensitive element of the optical imaging system satisfy: 0.5< DT11/ImgH <1, and more specifically, 0.71. ltoreq. DT 11/ImgH. ltoreq.0.87 can be further satisfied. On the premise that the imaging surface of the system meets the specification, the effective radius of the object side surface of the first lens is reasonably selected, so that the light incidence angle can be reasonably reduced, the system sensitivity is reduced, and the assembly stability is ensured.

In an exemplary embodiment, an effective focal length f1 of the first lens and an effective focal length f4 of the fourth lens may satisfy: -1.7< f1/f4< -1.1, more specifically, can further satisfy-1.52. ltoreq. f1/f 4. ltoreq.1.44. The configuration is beneficial to ensuring the miniaturization of the system, simultaneously can improve the field angle, realize the characteristic of ultra-wide angle, effectively correct various aberrations, improve the imaging quality and definition and simultaneously reduce the sensitivity.

In an exemplary embodiment, a separation distance T12 of the first lens and the second lens on the optical axis and a separation distance T67 of the sixth lens and the seventh lens on the optical axis may satisfy: 0.9< T12/T67<2.7, and more specifically, 0.94. ltoreq. T12/T67. ltoreq.2.64 can be further satisfied. Through reasonable arrangement of T12 and T67, the central thickness of each lens can be uniformly distributed on the premise of ensuring the imaging quality, and the production and assembly of the system lens are facilitated.

In an exemplary embodiment, a center thickness CT3 of the third lens on the optical axis and a center thickness CT6 of the sixth lens on the optical axis and a distance TTL of the object-side surface of the first lens to the imaging surface of the optical imaging system on the optical axis may satisfy: (CT3+ CT6)/TTL <0.15, more specifically, (CT3+ CT6)/TTL ≦ 0.13 may be further satisfied. By reasonably selecting the ratio of the third lens, the sixth lens and the total length of the optical system, the field curvature of the optical system can be effectively adjusted, the performance of the system is ensured, and the yield in the actual production of the lens is improved.

In an exemplary embodiment, 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 and an aperture value of the optical imaging system may satisfy: TTL/Fno <2.2(mm), more specifically, TTL/Fno ≦ 2.1 may be further satisfied. Through the scope of reasonable selection TTL and Fno, can be satisfying under the miniaturized prerequisite of camera lens, through reducing the light flux volume, reduce the influence of off-axis aberration to the system, promote like quality.

In an exemplary embodiment, the length ImgH of the diagonal of the effective pixel area of the electronic photosensitive element of the optical imaging system is half of the length of the diagonal of the effective pixel area, and the effective focal length f of the optical imaging lens of the optical imaging system satisfies the following condition: ImgH/f >1, more specifically, ImgH/f.gtoreq.1.21 can be further satisfied. By reasonably selecting the ratio of ImgH to f, the field angle of the system lens can be improved, and the characteristic of large field angle of the system lens is ensured.

In an exemplary embodiment, a center thickness CT2 of the second lens on the optical axis and a center thickness CT3 of the third lens on the optical axis may satisfy: 0.9< CT2/CT3<2.5, and more specifically, 0.93. ltoreq. CT2/CT 3. ltoreq.2.42 can be further satisfied. Through reasonably configuring the thickness of the second lens and the thickness of the third lens, the chromatic aberration of the system can be effectively reduced, the reasonable size of the lens is ensured, and the stability of the lens in the production process is ensured.

In an exemplary embodiment, a center thickness sum Σ CT of the first to seventh lenses on the optical axis and a distance TTL of the first lens object-side surface to the imaging surface of the optical imaging system on the optical axis may satisfy: sigma CT/TTL <0.6, and more specifically, Sigma CT/TTL < 0.5 can be further satisfied. By reasonably selecting sigma CT and TTL, the total length of the system lens, namely sigma CT, can be reduced to the maximum extent under the condition that TTL meets the specification, and the miniaturization of the system lens is ensured.

In an exemplary embodiment, 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 may satisfy: -1.6< R7/R8< -0.5, more specifically can further satisfy-1.57. ltoreq. R7/R8. ltoreq.0.61. By reasonably selecting the curvature radius of the fourth lens, the spherical aberration of the system can be effectively reduced, and the imaging quality of the system is improved.

In an exemplary embodiment, an effective radius DT11 of the object-side surface of the first lens and an effective radius DT72 of the image-side surface of the seventh lens may satisfy: 0.7< DT11/DT72<1.3, and more specifically, 0.87. ltoreq. DT11/DT 72. ltoreq.1.16 can be further satisfied. By reasonably selecting DT11 and DT72, the off-axis aberration of the system can be effectively corrected under the condition of meeting the assembly conditions, and the ultra-wide angle characteristic is realized.

In an exemplary embodiment, the optical imaging system may further include a stop STO for limiting the light beam, and the amount of light entering is adjusted to improve the imaging quality. 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 aperture of the optical imaging system can be effectively enlarged, the system sensitivity is reduced, the miniaturization of the lens is ensured, and the imaging quality is improved, so that the optical imaging system is more favorable for production and processing and is suitable for portable electronic products. In the embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The aspheric lens is characterized in that: the curvature varies continuously from the center to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, has the advantages of improving distortion aberration and astigmatic aberration, and can make the field of view larger and more realistic. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality. In addition, the use of the aspherical lens can also effectively reduce the number of lenses in the optical system.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the lens barrel 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 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 system includes seven lenses L1-L7 arranged in order from the object side to the imaging side along the optical axis. The first lens L1 has an object-side surface S1 and an image-side surface S2; the second lens L2 has an object-side surface S3 and an image-side surface S4; the third lens L3 has an object-side surface S5 and an image-side surface S6; the fourth lens L4 has an object-side surface S7 and an image-side surface S8; the fifth lens L5 has an object-side surface S9 and an image-side surface S10; the sixth lens L6 has an object-side surface S11 and an image-side surface S12 and the seventh lens L7 has an object-side surface S13 and an image-side surface S14.

In this embodiment, the first lens has a negative power, and the image-side surface thereof is concave; the fourth lens has positive focal power; the fifth lens has negative focal power, and the image side surface of the fifth lens is a concave surface; the seventh lens has negative focal power, the image side surface of the seventh lens is an aspheric surface, and at least one inflection point is formed. The second lens, the third lens and the sixth lens respectively have positive focal power. In the optical imaging system of the present embodiment, an aperture STO for limiting the light beam is further included. The optical imaging system according to embodiment 1 may include a filter L8 having an object side S15 and an image side S16, and the filter L8 may be used to correct color deviation. 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 the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical imaging system of example 1.

TABLE 1

As can be seen from table 1, the center thickness CT2 of the second lens L2 on the optical axis and the center thickness CT3 of the third lens L3 on the optical axis satisfy CT2/CT3 ═ 2.42; a separation distance T12 of the first lens L1 and the second lens L2 on the optical axis and a separation distance T67 of the sixth lens L6 and the seventh lens L7 on the optical axis satisfy T12/T67 as 1.51; and the radius of curvature R7 of the object side S7 of the fourth lens L4 and the radius of curvature R8 of the image side S8 of the fourth lens L4 satisfy-1.26 of R7/R8.

The embodiment adopts seven lenses as an example, and effectively enlarges the aperture of the lens, shortens the total length of the lens and ensures the large aperture and miniaturization of the lens by reasonably distributing the focal length and the surface type of each lens; meanwhile, various aberrations are corrected, and the resolution and the imaging quality of the lens are improved. Each aspherical surface type x is defined by the following formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is the conic coefficient (given in table 1 above); ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 below shows the coefficients A of the higher-order terms that can be used for the respective mirrors S1-S14 in example 1₄、A₆、A₈、A₁₀And A₁₂。

TABLE 2

Flour mark	A4	A6	A8	A10	A12
						S1	-9.6388E-02	2.7647E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	-1.2504E-01	2.2780E-01	0.0000E+00	0.0000E+00	0.0000E+00
						S3	-4.9214E-02	-2.4138E-01	8.2005E-02	1.7018E-01	0.0000E+00
S4	-3.7817E-01	5.2581E-01	-6.4127E-01	4.8083E-01	0.0000E+00
						S5	-4.7982E-01	1.1694E+00	-2.7158E+00	1.3790E+00	0.0000E+00
S6	1.2319E-01	9.8085E-03	-2.0124E+00	2.1905E+00	0.0000E+00
						S7	5.1450E-01	-9.4407E-01	8.3033E-01	0.0000E+00	0.0000E+00
S8	-2.3039E-01	4.3067E-01	-2.1810E-01	0.0000E+00	0.0000E+00
						S9	-6.0479E-01	1.2000E+00	-2.4522E+00	2.3430E+00	0.0000E+00
S10	3.9004E-02	1.4386E-01	-3.4025E-01	8.1873E-01	0.0000E+00
						S11	1.9786E-02	8.0143E-01	-2.1674E+00	2.8406E+00	-1.5778E+00
S12	-8.5896E-04	6.4411E-01	-2.4592E-01	-3.1166E-01	0.0000E+00
						S13	-3.0011E-01	1.6941E-01	-6.1868E-02	6.3830E-03	0.0000E+00
S14	-2.4703E-01	1.3387E-01	-5.4132E-02	6.5796E-03	0.0000E+00

Table 3 shown below gives the effective focal lengths f1 to f7 of the respective lenses of example 1, the effective focal length f of the imaging lens of the optical imaging system, the distance TTL on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S17 of the optical imaging system, half ImgH of the diagonal length of the effective pixel area of the electro-optical element of the optical imaging system, and the aperture value Fno of the optical imaging system.

TABLE 3

f(mm)	1.43	f6(mm)	2.65
				f1(mm)	-2.08	f7(mm)	-37.18
f2(mm)	5.30	TTL(mm)	4.80
				f3(mm)	-12.97	ImgH(mm)	1.80
f4(mm)	1.44	Fno	2.29
				f5(mm)	-1.96

According to table 3, f1/f4 ═ -1.44 is satisfied between the effective focal length f1 of the first lens L1 and the effective focal length f4 of the fourth lens L4; the distance TTL between the object side surface S1 of the first lens L1 and the imaging surface S17 of the optical imaging system on the optical axis and the aperture value Fno of the optical imaging system satisfy TTL/Fno of 2.1 (mm); and the effective focal length f of the optical imaging system optical imaging lens satisfies the condition that ImgH/f is 1.26 between half of the diagonal length of the effective pixel area of the electronic photosensitive element of the optical imaging system and the effective focal length f of the optical imaging lens of the optical imaging system.

In this embodiment, a total sum Σ CT of central thicknesses on the optical axis of the first lens L1 to the seventh lens L7 and a distance TTL on the optical axis of the first lens L1 object side surface S1 to the imaging surface S17 of the optical imaging system satisfy Σ CT/TTL of 0.44; the central thickness CT3 of the third lens L3 on the optical axis and the central thickness CT6 of the sixth lens L6 on the optical axis satisfy (CT3+ CT6)/TTL of 0.11 between the distance TTL of the object-side surface S1 of the first lens L1 to the imaging surface S17 of the optical imaging system on the optical axis; the effective radius DT11 of the object side S1 of the first lens L1 and the effective radius DT72 of the image side S14 of the seventh lens L7 meet the condition that DT11/DT72 is 1.16; and the effective radius DT11 of the object side S1 of the first lens L1 and the half of the diagonal length ImgH of the effective pixel area of the electronic photosensitive element of the optical imaging system satisfy that DT11/ImgH is 0.87.

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 optical imaging system. 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 the distortion magnitude values in the case of different viewing angles. Fig. 2D shows a chromatic aberration of magnification curve of the optical imaging system of embodiment 1, which represents the deviation of different image heights on the imaging plane after the light passes through the optical imaging system. As can be seen from fig. 2A to 2D, 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 4D. The optical imaging systems described in embodiment 2 and the following embodiments are the same in arrangement structure as the optical imaging system described in embodiment 1 except for parameters of the respective lenses of the optical imaging system, such as a radius of curvature, a thickness, a conic coefficient, an effective focal length, an on-axis pitch, a coefficient of a higher-order term of the respective mirror surfaces, and the like. For the sake of brevity, descriptions similar to those of embodiment 1 will be omitted.

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 according to embodiment 2 includes first to seventh lenses L1-L7 having an object side surface and an image side surface, respectively. Table 4 below shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical imaging system of example 2. Table 5 shows the high-order coefficient of each aspherical mirror surface in example 2. Table 6 shows the effective focal lengths f1 to f7 of the respective lenses, the effective focal length f of the imaging lens of the optical imaging system, the distance TTL on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S17 of the optical imaging system, the half ImgH of the diagonal length of the effective pixel area of the electro-optical element of the optical imaging system, and the aperture value Fno of the optical imaging system of example 2. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 4

TABLE 5

TABLE 6

f(mm)	1.20	f6(mm)	-404.88
				f1(mm)	-1.63	f7(mm)	5.63
f2(mm)	-77.45	TTL(mm)	4.70
				f3(mm)	-11.04	ImgH(mm)	1.80
f4(mm)	1.07	Fno	2.29
				f5(mm)	-4.37

Fig. 4A shows an on-axis chromatic aberration curve of the optical imaging system of embodiment 2, which represents the convergent focus deviation of light rays of different wavelengths after passing through the optical imaging system. 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 the distortion magnitude values in the case of different viewing angles. 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 optical imaging system. As can be seen from fig. 4A to 4D, 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 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 system according to embodiment 3 includes first to seventh lenses L1-L7 having an object side surface and an image side surface, respectively. Table 7 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical imaging system of example 3. Table 8 shows the high-order coefficient of each aspherical mirror surface in example 3. Table 9 shows effective focal lengths f1 to f7 of the respective lenses, an effective focal length f of the imaging lens of the optical imaging system, a distance TTL on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S17 of the optical imaging system, a half ImgH of the diagonal length of the effective pixel area of the electro-optical element of the optical imaging system, and an aperture value Fno of the optical imaging system of example 3. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 7

TABLE 8

TABLE 9

f(mm)	1.49	f6(mm)	3.17
				f1(mm)	-1.88	f7(mm)	74.05
f2(mm)	-4.94	TTL(mm)	4.60
				f3(mm)	5.30	ImgH(mm)	1.80
f4(mm)	1.24	Fno	2.29
				f5(mm)	-2.14

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 optical imaging system. 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 the distortion magnitude values in the case of different viewing angles. 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 optical imaging system. As can be seen from fig. 6A to 6D, 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 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 system according to embodiment 4 includes first to seventh lenses L1-L7 having an object side surface and an image side surface, respectively. Table 10 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical imaging system of example 4. Table 11 shows the high-order coefficient of each aspherical mirror surface in example 4. Table 12 shows the effective focal lengths f1 to f7 of the respective lenses, the effective focal length f of the imaging lens of the optical imaging system, the distance TTL on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S17 of the optical imaging system, the half ImgH of the diagonal length of the effective pixel area of the electro-optical element of the optical imaging system, and the aperture value Fno of the optical imaging system of example 4. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

Watch 10

TABLE 11

Flour mark	A4	A6	A8	A10	A12
						S1	-1.2148E-01	3.0469E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	-3.9029E-02	3.2329E-01	0.0000E+00	0.0000E+00	0.0000E+00
						S3	6.8402E-02	-3.1175E-01	4.1208E-01	-2.9149E-01	0.0000E+00
S4	-8.4807E-01	1.5795E+00	-1.8909E+00	1.1194E+00	0.0000E+00
						S5	-2.0465E-01	-7.8586E-01	1.2098E+00	-1.0081E+00	0.0000E+00
S6	4.8573E-01	-2.3392E+00	3.6263E+00	-2.9735E+00	0.0000E+00
						S7	1.5457E-01	2.9181E-02	2.2202E-01	0.0000E+00	0.0000E+00
S8	-2.5289E-01	4.2498E-01	9.0870E-02	0.0000E+00	0.0000E+00
						S9	-2.7258E-01	2.5577E-01	-3.0627E-01	-2.0493E+00	0.0000E+00
S10	1.3769E-01	4.8072E-02	-4.7434E-01	7.5325E-01	0.0000E+00
						S11	-3.6038E-02	1.1432E+00	-2.9295E+00	3.9103E+00	-2.5112E+00
S12	1.9185E-02	9.1504E-01	-6.1013E-01	-2.8246E-01	0.0000E+00
						S13	-3.3177E-01	1.9923E-01	-6.2106E-02	3.7199E-03	0.0000E+00
S14	-2.9613E-01	1.6988E-01	-6.2986E-02	6.6466E-03	0.0000E+00

TABLE 12

f(mm)	1.43	f6(mm)	2.75
				f1(mm)	-1.81	f7(mm)	95.65
f2(mm)	-6.53	TTL(mm)	4.50
				f3(mm)	5.39	ImgH(mm)	1.80
f4(mm)	1.26	Fno	2.39
				f5(mm)	-2.16

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 optical imaging system. 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 the distortion magnitude values in the case of different viewing angles. Fig. 8D shows a chromatic aberration of magnification curve of the optical imaging system of example 4, which represents the deviation of different image heights on the imaging plane after the light passes through the optical imaging system. As can be seen from fig. 8A to 8D, 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 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 system according to embodiment 5 includes first to seventh lenses L1-L7 having an object side surface and an image side surface, respectively. Table 13 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical imaging system of example 5. Table 14 shows the high-order coefficient of each aspherical mirror surface in example 5. Table 15 shows effective focal lengths f1 to f7 of the respective lenses, an effective focal length f of the imaging lens of the optical imaging system, a distance TTL on the optical axis from the object side surface S1 of the first lens L1 to the imaging surface S17 of the optical imaging system, a half ImgH of the diagonal length of the effective pixel area of the electro-optical element of the optical imaging system, and an aperture value Fno of the optical imaging system of example 5. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

Watch 13

TABLE 14

Flour mark	A4	A6	A8	A10	A12
						S1	-1.0549E-01	1.9999E-02	0.0000E+00	0.0000E+00	0.0000E+00
S2	-2.9924E-02	5.5539E-02	0.0000E+00	0.0000E+00	0.0000E+00
						S3	1.5504E-01	-4.6335E-01	3.2921E-01	-1.7900E-01	0.0000E+00
S4	-5.5093E-01	4.7787E-01	-2.7791E-01	7.0353E-02	0.0000E+00
						S5	-1.2236E-01	-1.4212E+00	2.8452E+00	-2.0855E+00	0.0000E+00
S6	2.1880E-01	-1.2917E+00	2.6563E+00	-2.1628E+00	0.0000E+00
						S7	1.6318E-01	2.2619E-01	-2.1248E-01	0.0000E+00	0.0000E+00
S8	-6.7354E-02	-5.6628E-02	1.7576E-01	0.0000E+00	0.0000E+00
						S9	-2.7354E-01	9.8077E-01	-3.3141E+00	2.9002E+00	0.0000E+00
S10	-2.6411E-01	1.6531E+00	-3.7171E+00	3.5954E+00	0.0000E+00
						S11	-2.0075E-01	3.2600E-01	1.3545E+00	-3.3904E+00	2.6298E+00
S12	-6.3692E-04	-1.1724E-01	7.4522E-01	-3.6156E-01	0.0000E+00
						S13	-1.8158E-01	2.2969E-01	-1.3521E-01	3.0687E-02	0.0000E+00
S14	-1.0130E-01	7.9502E-02	-4.2843E-02	6.7268E-03	0.0000E+00

Watch 15

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 optical imaging system. 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 example 5, which represents the distortion magnitude values in the case of different viewing angles. Fig. 10D shows a chromatic aberration of magnification curve of the optical imaging system of example 5, which represents the deviation of different image heights on the imaging plane after the light passes through the optical imaging system. As can be seen from fig. 10A to 10D, the optical imaging system according to embodiment 5 can achieve good imaging quality.

In summary, examples 1 to 5 each satisfy the relationship shown in table 16 below.

TABLE 16

Examples \ formulas	1	2	3	4	5
						f1/f4	-1.44	-1.52	-1.52	-1.44	-1.50
TTL/Fno	2.10	2.06	2.01	1.89	2.09
						ImgH/f	1.26	1.50	1.21	1.26	1.24
CT2/CT3	2.42	1.64	0.93	1.05	1.45
						T12/T67	1.51	2.64	1.53	1.62	0.94
∑CT/TTL	0.44	0.50	0.43	0.41	0.42
						R7/R8	-1.26	-0.61	-0.75	-0.73	-1.57
(CT3+CT6)/TTL	0.11	0.12	0.10	0.12	0.13
						DT11/DT72	1.16	1.11	0.87	0.97	0.99
DT11/ImgH	0.87	0.79	0.80	0.74	0.71

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 sequentially includes, from an object side to an image side along an optical axis, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element,

it is characterized in that the preparation method is characterized in that,

the first lens has negative focal power, and the image side surface of the first lens is a concave surface;

the fourth lens has positive focal power, the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface;

the fifth lens has positive focal power or negative focal power, and the image side surface of the fifth lens is a concave surface;

the seventh lens has positive optical power or negative optical power;

the second lens, the third lens and the sixth lens respectively have positive focal power or negative focal power; and

the effective radius DT11 of the object side surface of the first lens and the effective radius DT72 of the image side surface of the seventh lens satisfy that: 0.7< DT11/DT72< 1.3.

2. The optical imaging system of claim 1, wherein the seventh lens element has an aspheric image-side surface and at least one inflection point.

3. The optical imaging system of claim 1, wherein a separation distance T12 between the first and second lenses on the optical axis and a separation distance T67 between the sixth and seventh lenses on the optical axis satisfy: 0.9< T12/T67< 2.7.

4. The optical imaging system of claim 1, satisfying (CT3+ CT6)/TTL <0.15,

wherein CT3 is a central thickness of the third lens element on the optical axis, CT6 is a central thickness of the sixth lens element on the optical axis, and TTL is a distance from the object-side surface of the first lens element to the imaging surface of the optical imaging system on the optical axis.

5. The optical imaging system of claim 4, wherein 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 and an aperture value Fno of the optical imaging system satisfy: TTL/Fno <2.2 (mm).

6. The optical imaging system as claimed in claim 1, wherein the optical imaging system has an effective focal length f between ImgH which is half of the diagonal length of the effective pixel area of the electronic photosensitive element and the effective focal length f of the optical imaging system: ImgH/f > 1.

7. The optical imaging system of claim 1, wherein a center thickness CT2 of the second lens on the optical axis and a center thickness CT3 of the third lens on the optical axis satisfy: 0.9< CT2/CT3< 2.5.

8. The optical imaging system according to claim 4, wherein a sum Σ CT of central thicknesses of the first lens to 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: sigma CT/TTL < 0.6.

9. The optical imaging system as claimed in claim 1, wherein an effective radius DT11 of the object side surface of the first lens and a half ImgH of a diagonal length of an effective pixel area of an electro-optical sensor of the optical imaging system satisfy: 0.5< DT11/ImgH <1.

10. The optical imaging system of any of claims 1-9, wherein the object side surface of the seventh lens is convex.