CN115407485A

CN115407485A - Optical system, image capturing device and terminal equipment

Info

Publication number: CN115407485A
Application number: CN202210908567.3A
Authority: CN
Inventors: 贾远林; 林柏宇; 江依达; 王海燕; 叶海水
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2022-11-29
Also published as: CN113126248B; CN113126248A

Abstract

The embodiment of the application provides an optical system, image capturing device and terminal equipment, and the optical system comprises an object plane, an image plane, a diaphragm, an optical filter and seven lenses, and a non-rotationally symmetrical aspheric surface is arranged on at least one lens in the seven lenses, so that the imaging effect of ultra-wide angle and small distortion is realized. By applying the optical system to the image capturing device and the terminal equipment, the functions of the image capturing device and the terminal equipment are enhanced, and the user experience is improved.

Description

Optical system, image capturing device and terminal equipment

Technical Field

The present application relates to the field of optical imaging technologies, and in particular, to an optical system, an image capturing device, and a terminal device.

Background

With the increasing demand for photographing terminal devices such as mobile phones, higher requirements are placed on the quality and diversity of lens imaging in the field of view environment, such as larger chip size, larger aperture, smaller image distortion, and the like. For the requirement of adaptation user, the module of making a video recording also develops towards big chip, big light ring, little distortion gradually.

At present, a mobile phone camera module often adopts a super wide-angle imaging system, and the design of a super wide-angle lens is difficult to compress to a lower degree due to a large visual angle and a limited structural size. Therefore, the ultra-wide angle imaging systems of some mobile phones in the market have larger optical distortion, and the optical distortions can be obviously sensed by users in actual use or distortion correction needs to be started. In the application of terminal equipment, when the super wide-angle lens is used for recording videos, real-time distortion correction can be performed on video images, so that a large amount of processing resources in the terminal equipment can be consumed, and the power consumption and the processing speed of the equipment are greatly challenged.

Therefore, an ultra-wide angle lens capable of optimizing the optical imaging quality and reducing the optical distortion is needed to meet the market demand.

Disclosure of Invention

The application provides an optical system, an image capturing device and a terminal device, which aim to solve the prior art.

In a first aspect, the present application provides an optical system comprising: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are sequentially arranged from the object plane to the image plane along the optical axis direction; the first lens, the second lens, the fourth lens, and the seventh lens have negative optical power; the third lens and the fifth lens have positive optical power; the sixth lens has optical power; wherein at least one of the first lens, the second lens, the fourth lens, the sixth lens, and the seventh lens has a non-rotationally symmetric aspherical surface. Through the scheme provided by the embodiment, the non-rotationally symmetrical aspheric surface is arranged on the lens with negative focal power, so that the distortion of an image on an image surface is reduced, the ultra-wide-angle and small-distortion imaging effect of an optical system can be realized, and the distortion correction is performed on scenes such as video recording and shooting preview without an algorithm.

In one possible design, the rotationally asymmetric aspheric surface is disposed on the seventh lens. With the arrangement provided by the present embodiment, the non-rotationally symmetric aspheric surface of the seventh lens functions to correct aberrations.

In one possible design, the TV distortion of the image made by the optical system on the image plane is TDT, which satisfies the following formula: the absolute TDT is less than or equal to 3.0 percent. By the scheme provided by the embodiment, the TV distortion TDT is controlled to be less than 3.0%, and the distortion is further reduced.

In one possible design, the maximum extent of the image formed by the optical system on the image plane has a length Imgx in the x-direction and a length Imgy in the y-direction, and the half-image height of the image is Imgy/Imgx, which satisfies the following formula: imgy/Imgx =0.75. Through the scheme that this embodiment provided, promote the imaging quality, increase intelligent terminal's shooting competitiveness.

In one possible design, the field of view of the optical system is the FOV, which satisfies the following formula: FOV is more than or equal to 100 degrees and less than or equal to 130 degrees. Through the scheme provided by the embodiment, the ultra-wide angle function is realized.

In one possible embodiment, a diaphragm is arranged between the second lens and the third lens. Through the scheme provided by the embodiment, the light entering amount and the F number of the lens of the optical system are determined, so that the F number is reduced, and the aperture is enlarged.

In one possible design, the total optical length of the optical system is TTL, and half the length of the diagonal of the imaging area on the image plane is ImgH, which satisfies the following formula: TTL/ImgH is less than or equal to 1.7. Through the scheme provided by the embodiment, when the total optical length TTL of the lens is reduced, the pixels of the image formed on the image plane are not reduced or not obviously reduced, the imaging quality and the ultra-wide angle are ensured, and meanwhile, the thickness of the lens is thin, so that the space of the terminal equipment can be saved.

In one possible design, the fifth lens element has a fifth object side surface and a fifth image side surface, the fifth object side surface has a fifth object side away from the optical axis and a fifth object side center located on the optical axis, the fifth image side surface has a fifth image side away from the optical axis and a fifth image side center located on the optical axis, the fifth object side surface and the fifth image side surface are curved toward the object plane with respect to the fifth object side center and the fifth image side center, respectively, the fifth object side surface and the fifth image side surface are convex toward the image plane with respect to the fifth object side edge and the fifth image side edge, respectively, a radius of curvature R9 of the fifth object side surface is greater than a radius of curvature R10 of the fifth image side surface, and a relationship between 4.7 ≦ R9/R10 ≦ 5.7 is satisfied. Through the scheme provided by the embodiment, the fifth lens performs secondary convergence on the light rays so as to control the size of the light spot.

In one possible design, the sixth lens has a sixth object-side surface and a sixth image-side surface, the sixth object-side surface has a sixth object-side edge away from the optical axis and a sixth object-side center on the optical axis, the sixth image-side surface has the sixth image-side edge away from the optical axis and a sixth image-side center on the optical axis, a region of the sixth object-side surface close to the sixth object-side and a region of the sixth image-side surface close to the sixth image-side are respectively curved toward the object plane, both the sixth object-side center and the sixth image-side center are convex toward the object plane, and an effective focal length f6 of the sixth lens and an effective focal length fx of the optical system in the x-axis direction satisfy-6.5 f6/fx ≦ 5.5. Through the scheme that this embodiment provided, the sixth lens is diverged and is redistributed twice to the light that converges for the facula that the light that passes through the sixth lens outgoing formed, light intensity distribution is more even.

In one possible design, the seventh lens element has a seventh object-side surface and a seventh image-side surface, the seventh object-side surface has a seventh object-side edge far from the optical axis and a seventh object-side center located on the optical axis, the seventh image-side surface has a seventh image-side edge far from the optical axis and a seventh image-side center located on the optical axis, a region of the seventh object-side surface close to the seventh object-side edge and a region of the seventh image-side surface close to the seventh image-side edge are respectively curved toward the image plane, the seventh object-side center and the seventh image-side center are both convex toward the object plane, and a radius of curvature R13 of the seventh object-side surface and a radius of curvature R14 of the seventh image-side surface satisfy 1.4 ≦ R13/R14 ≦ 1.7. Through the scheme that this embodiment provided, the seventh lens is dispersed and is redistributed the light of redistribution to the secondary and is carried out the cubic and disperse and the secondary and redistribute for the pixel point of the formation of image on the image plane distributes evenly, the distortion is littleer, imaging quality is higher.

Through the scheme provided by the embodiment, the focal power of the fifth lens, the sixth lens and the seventh lens is reasonably distributed, so that high-quality imaging performance is realized.

In one possible design, the optical system has an effective focal length fx in an x-axis direction of a plane perpendicular to the optical axis, an effective focal length fy in a y-axis direction of the plane perpendicular to the optical axis, and an entrance pupil diameter EPD, which satisfies the following formula: fx/EPD =2.0, fy/EPD =2.0. Through the scheme that this embodiment provided, the diaphragm number sets up to 2.0, can promote shutter speed for the light inlet amount of camera lens is big, and application scope is wider.

In one possible design, the third lens element has a third image side surface having a radius of curvature R6 in a y-axis direction of a plane perpendicular to the optical axis, the fifth lens element has a fifth image side surface having a radius of curvature R10 in the y-axis direction of the plane perpendicular to the optical axis, and an effective focal length of the optical system in the y-axis direction of the plane perpendicular to the optical axis is fy, which satisfies the following equation: -0.75 ≦ (R6-R10)/fy ≦ -0.5. By the scheme provided by the embodiment, the light spot can be enlarged by the primary convergence of the third lens and the secondary convergence of the fifth lens.

In one possible design, the seventh lens has a seventh object-side surface and a seventh image-side surface, which are each centrosymmetric about the optical axis. According to the scheme provided by the embodiment, the seventh object side surface of the seventh lens is symmetric about the optical axis center, so that light rays incident on the seventh image side surface of the seventh lens are ensured to be symmetric about the optical axis center, the seventh image side surface of the seventh lens is symmetric about the optical axis center, and an image formed on the image plane is ensured to be centered on the image plane and also be symmetric about the optical axis center.

In a second aspect, the present application provides an image capturing apparatus, which includes the optical system of the first aspect. The optical system provided by the first aspect is arranged in the image capturing device, so that the length of a lens of the image capturing device can be shortened, the field angle is increased, the distortion is reduced under the condition that the imaging size of an image surface is basically unchanged, and the image capturing device combining an ultra-wide angle and small distortion is realized.

In a third aspect, the present application provides a terminal device, which includes the image capturing device provided in the second aspect. By arranging the image capturing device with the optical system provided by the first aspect in the terminal equipment, various shooting application scenes under different large view fields can be realized, the functions of the terminal equipment are enhanced, and the user experience is improved.

Therefore, in each aspect, by introducing the non-rotationally symmetrical aspheric lens into the optical system, the design freedom is increased, the lens imaging quality under a compact system is improved, the imaging effect of ultra wide angle and small distortion is realized, scenes such as video recording and shooting preview and the like do not need to be corrected by an algorithm, and the lens can be used for terminal equipment to shoot and record images, for example, the lens of portable electronic products such as mobile phones, tablet computers and monitors are used for shooting scenes of external videos and photos, and the lens comprises various shooting application scenes under different large fields of view.

Drawings

Fig. 1 is a schematic view of an optical system provided in embodiment 1 of the present application;

fig. 2 is a schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in embodiment 1 of the present application;

fig. 3 is a schematic view of an optical system provided in embodiment 2 of the present application;

fig. 4 is a schematic diagram of a mesh distortion of an image formed on an image plane in an optical system provided in fig. 2;

fig. 5 is a schematic view of an optical system provided in embodiment 3 of the present application;

fig. 6 is a schematic diagram of a mesh distortion of an image formed on an image plane in an optical system provided in 3 provided in the present application;

fig. 7 is a schematic view of an optical system provided in embodiment 4 of the present application;

fig. 8 is a schematic diagram of a mesh distortion of an image formed on an image plane in an optical system provided in 4;

fig. 9 is a schematic view of an optical system provided in embodiment 5 of the present application;

fig. 10 is a schematic diagram illustrating a mesh distortion of an image formed on an image plane in an optical system provided in fig. 5;

fig. 11 is a schematic view of an optical system provided in embodiment 6 of the present application;

fig. 12 is a schematic diagram of a grid distortion of an image formed on an image plane in an optical system according to claim 6.

Reference numerals are as follows:

1-a first lens;

2-a second lens;

3-a third lens;

4-a fourth lens;

5-a fifth lens;

6-sixth lens;

7-a seventh lens;

8-object plane;

9-a diaphragm;

10-an optical filter;

11-optical axis;

s1-a first object side;

s2, a first image side surface;

s3, a second object side surface;

s4, a second image side surface;

s5, a third object side;

s6, a third image side;

s7-a fourth object side;

s8-the fourth image side;

s9-the fifth object side;

s10, a fifth image side;

s11-the sixth object side;

s12, a sixth image side;

s13-the seventh object side;

s14-the seventh image side;

s15, filtering the side surface of the optical filter;

s16, filtering the image side surface of the optical filter;

s17-image plane.

Detailed Description

The terminology used in the description of the embodiments section of the present application is for the purpose of describing particular embodiments of the present application only and is not intended to be limiting of the present application.

It should be understood that the embodiments described are only a few embodiments of the present application, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be noted that the terms "upper", "lower", "left", "right", and the like used in the embodiments of the present application are described in terms of the angles shown in the drawings, and should not be construed as limiting the embodiments of the present application. In addition, in this context, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on "or" under "the other element or be indirectly on" or "under" the other element via an intermediate element.

Referring to fig. 1-12, fig. 1 is a schematic diagram of an optical system provided in embodiment 1 of the present application; fig. 2 is a schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in embodiment 1 of the present application; fig. 3 is a schematic view of an optical system provided in embodiment 2 of the present application; fig. 4 is a schematic diagram of a mesh distortion of an image formed on an image plane in an optical system provided in fig. 2; fig. 5 is a schematic diagram of an optical system provided in embodiment 3 of the present application; fig. 6 is a schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 3 provided in the present application;

fig. 7 is a schematic view of an optical system provided in embodiment 4 of the present application; fig. 8 is a schematic diagram of a mesh distortion of an image formed on an image plane in an optical system provided in 4; fig. 9 is a schematic view of an optical system provided in embodiment 5 of the present application; fig. 10 is a schematic diagram illustrating grid distortion of an image formed on an image plane in an optical system according to claim 5 provided in the present application; fig. 11 is a schematic view of an optical system provided in embodiment 6 of the present application; fig. 12 is a schematic diagram of grid distortion of an image formed on an image plane in an optical system according to item 6.

The lens is different from a professional single lens reflex camera, the height of the lens suitable for the terminal equipment is limited, and the lens suitable for the terminal equipment is a common ultra-wide-angle lens in order to meet the basic photographing requirement of a user.

As shown in fig. 1, 3, 5, 7, 9 and 11, embodiments 1 to 6 of the present application provide an optical system. The optical system comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6 and a seventh lens 7, which are arranged on an optical axis 11 in sequence from an object plane 8 to an image plane S17. The optical system is composed of seven lenses into lens groups, and the power setting of each lens in the lens groups is different.

The power, equal to the difference between the image-side and object-side beam convergence, characterizes the ability of the optical system to deflect light. The lens has a converging action if the optical power is positive and a diverging action if the optical power is negative.

Specifically, the first lens element 1 has negative power, the first object-side surface S1 of the first lens element 1 has a first object-side edge away from the optical axis 11 and a first object-side center located on the optical axis 11, the first image-side surface S2 of the first lens element 1 has a first image-side edge away from the optical axis 11 and a first image-side center located on the optical axis 11, the first object-side surface S1 and the first image-side surface S2 are curved toward the image plane S17 with respect to the first object-side center and the first image-side center, respectively, and the first object-side edge and the first image-side edge are curved toward the image plane S17 with respect to the first object-side center and the first image-side center, respectively. The first lens 1 is arranged so that the periphery thereof protrudes toward the image plane S17 and the center thereof protrudes toward the image plane S17, and the first lens 1 is configured to receive more incident light, thereby increasing the field angle of the optical system and realizing a wide-angle function.

The second lens 2 has a negative power, and has a second object-side surface S3 and a second image-side surface S4, both of which are curved toward the image plane S17, and a second object-side edge and a second image-side edge remote from the optical axis 11, the second object-side surface S3 and the second image-side surface S4 being convex toward the object plane 8, and a radius of curvature of the second object-side surface S3 being larger than a radius of curvature of the second image-side surface S4. The second lens 2 is a concave lens having a crescent shape whose periphery is curved toward the image plane S17 with respect to the center, so that the light refracted by the first lens 1 is further deflected in a direction away from the optical axis 11, and the included angle with the optical axis 11 is smaller.

The third lens element 3 has positive power and has a third object-side surface S5 and a third image-side surface S6, wherein the third object-side surface S5 is a convex surface protruding toward the object side, and the third image-side surface S6 is a convex surface protruding toward the image side. The third lens 3 is set to be two convex lenses, and the light rays which are further deflected by the second lens 2 and have smaller included angle with the optical axis 11 are converged.

The fourth lens element 4 has a negative power and has a fourth object-side surface S7 and a fourth image-side surface S8, the fourth object-side surface S7 has a fourth object-side edge away from the optical axis 11 and a fourth object-side center located on the optical axis 11, the fourth image-side surface S8 has a fourth image-side edge away from the optical axis 11 and a fourth image-side center located on the optical axis 11, the fourth object-side edge and the fourth image-side edge are curved toward the object plane 8 with respect to the fourth object-side center and the fourth image-side center, respectively, the fourth object-side surface S7 and the fourth image-side surface S8 are both convex toward the image plane S17, and a radius of curvature of the fourth object-side surface S7 is smaller than a radius of curvature of the fourth image-side surface S8. The fourth lens 4 is provided as a concave lens having a crescent shape whose periphery is curved with respect to the center toward the object plane 8, and deflects the light rays converged by the third lens 3 so that the light rays diverge in a direction away from the optical axis 11.

The fifth lens element 5 has positive optical power, and has a fifth object-side surface S9 and a fifth image-side surface S10, the fifth object-side surface S9 has a fifth object-side edge away from the optical axis 11 and a fifth object-side center on the optical axis 11, the fifth image-side surface S10 has a fifth image-side edge away from the optical axis 11 and a fifth image-side center on the optical axis 11, the fifth object-side surface S9 and the fifth image-side surface S10 are curved toward the object plane 8 with respect to a fifth object-side center and a fifth image-side center, respectively, the fifth object-side center and the fifth image-side center are convex toward the image plane S17 with respect to the fifth object-side edge and the fifth image-side edge, respectively, a radius of curvature R9 of the fifth object-side surface S9 is larger than a radius of curvature R10 of the fifth image-side surface S10, and a ratio R9/R10<5.7 of 4.7 is satisfied. The fifth lens 5 is set to be a convex lens with the periphery curved towards the object plane 8 and two convex surfaces convex towards the image plane S17, and the light rays diverging through the fourth lens 4 are converged for the second time, so that the light rays are transmitted towards the direction close to the optical axis 11 to control the size of the light spot.

The sixth lens element 6 has a power, which may be positive or negative, and has a sixth object-side surface S11 having a sixth object-side surface remote from the optical axis 11 and a sixth object-side center located on the optical axis 11, a sixth image-side surface S12 of the sixth lens element 6 having a sixth image-side surface remote from the optical axis 11 and a sixth image-side center located on the optical axis 11, a region of the sixth object-side surface S11 close to the sixth object-side surface and a region of the sixth image-side surface S12 close to the sixth image-side surface each being curved toward the object plane 8, the sixth object-side surface and the sixth image-side surface each being curved toward the object plane 8 with respect to a sixth object-side center and a sixth image-side center each being convex toward the object plane 8, an effective focal length f6 of the sixth lens element 6 and an effective focal length fx of the lens group in the x-axis direction satisfying-6.5 f6/fx ≦ 5.5. The sixth lens 6 is arranged to be of a structure that the periphery is bent towards the object plane 8 and the center is protruded towards the object plane 8, and light rays converged by the fifth lens 5 are subjected to secondary divergence and light ray redistribution, so that light spots formed by the light rays emitted by the sixth lens 6 are more uniform in light intensity distribution.

The seventh lens element 7 has a negative optical power, a seventh object side surface S13 of the seventh lens element 7 has a seventh object side surface away from the optical axis 11 and a seventh object side center located on the optical axis 11, a seventh image side surface S14 of the seventh lens element 7 has a seventh image side surface away from the optical axis 11 and a seventh image side center located on the optical axis 11, a region of the seventh object side surface S13 close to the seventh object side surface and a region of the seventh image side surface S14 close to the seventh image side surface are each curved toward the object surface 8, the seventh object side surface and the seventh image side surface are each curved toward the object surface 8 with respect to the seventh object side center and the seventh image center, the seventh object side center and the seventh image side center are each convex toward the object surface 8, and a radius of curvature R13 of the seventh object side surface S13 and a radius of curvature R14 of the seventh image side surface S14 satisfy 1.4 mm R13/R14<1.7. The seventh lens 7 is arranged to be of a structure that the periphery is bent towards the object plane 8 and the center is protruded towards the object plane 8, and light rays which are secondarily dispersed and redistributed by the sixth lens 6 are secondarily dispersed and secondarily redistributed, so that pixel points of images formed by the light rays emitted to the image plane S17 through the seventh lens 7 are uniformly distributed, the distortion is smaller, and the imaging quality is higher.

In this optical system, at least one of the first lens 1, the second lens 2, the fourth lens 4, the sixth lens 6, and the seventh lens 7 has a non-rotationally symmetric aspherical surface. Specifically, the number of non-rotationally symmetrical aspherical surfaces provided in the five lenses having negative refractive power may be 1 to 10, and there are countless arrangements depending on the arrangement and combination, and the lenses have non-rotationally symmetrical aspherical surfaces as the object-side surface and/or the image-side surface of the lenses. The surfaces of other lenses that are not configured with non-rotationally symmetric aspheres may be configured with spherical or aspherical surfaces commonly used in the art, such as Q-type aspheres.

The present application preferably takes the case where the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens element 7 are configured as non-rotationally symmetrical aspheric surfaces, and twelve surfaces of the first lens element 1 to the sixth lens element 6 are all Q-shaped aspheric surfaces, which is only for convenience of illustration and does not limit the scope of the present application.

In this optical system, the surface shapes of the twelve Q-type aspheric surfaces of the first lens 1 to the sixth lens 6 may satisfy, but are not limited to, being defined using the following aspheric surface formulas:

wherein z is the rise of the aspheric surface, r is the radial coordinate of the aspheric surface, c is the vertex curvature of the aspheric surface, K is the conic constant, a _m Is an aspheric coefficient, r _max U = r/r as maximum radial radius coordinate _max 。

The non-rotationally symmetrical aspherical surface shape of the seventh lens 7 is defined using the following aspherical surface formula:

wherein z is the rise of the vector parallel to the z axis; n is the total number of polynomial coefficients in the series, ai is the coefficient of the ith expansion polynomial, r is the radial coordinate of the aspheric surface, c is the curvature of the aspheric surface vertex sphere, and K is a conic constant.

The TV distortion of the image formed on the image plane S17 through the optical system is TDT, and the TV distortion (TV distortion) is a relative distortion, that is, a degree of deformation of the actual image. The optical system can control the TV distortion TDT to be below 3.0%, reduce the distortion of an image on an image surface S17, realize the ultra-wide-angle and small-distortion imaging effect of the optical system, and carry out distortion correction on scenes such as video recording, shooting preview and the like without an algorithm.

Further, in the optical system, the maximum range of the image formed by the imaging region of the optical system on the image plane S17 is Imgx in the x direction, imgy in the y direction, and Imgy/Imgx in the half-image height of the image, which satisfies the following formula: imgy/Imgx =0.75, an imaging area with the resolution of 4.

An angle between two straight lines between an edge of a region where light rays emitted from the object plane 8 can be received by the first object-side surface S1 of the first lens 1 and the first object-side surface of the first lens 1 is referred to as a field angle FOV of the optical system, and satisfies the following formula: FOV is more than or equal to 100 degrees and less than or equal to 130 degrees, and the ultra-wide angle function is realized.

Further, an aperture stop 9 is provided between the second lens 2 and the third lens 3, and the amount of light entering the lens of the optical system and the F-number are determined by the aperture stop 9, which contributes to reducing the F-number and increasing the aperture. Wherein F number is an F-number, the diaphragm is a device for controlling the amount of light irradiated to the photosensitive element through the lens, the expression of the diaphragm size is represented by F number/F value, and the F number is a relative value (reciprocal of relative aperture) obtained by the focal length/lens light-passing diameter of the lens.

Further, the total optical length of the optical system is TTL, and half of the length of the diagonal line of the imaging area on the image plane S17 is ImgH, which satisfies the following formula: TTL/ImgH is more than or equal to 1.2 and less than or equal to 1.7. The diagonal line of the imaging area on the image surface S17 is the diagonal line of the rectangular area with the resolution ratio of 4.

In the optical system, an effective focal length of the optical system in an x-axis direction of a plane perpendicular to the optical axis 11 is fx, an effective focal length in a y-axis direction of a plane perpendicular to the optical axis 11 is fy, an entrance pupil diameter is EPD, which satisfies the following formula: fx/EPD =2.0, fy/EPD =2.0. At this time, the f-number of the lens group is set to 2.0, which can increase the shutter speed, so that the lens has a large light-entering amount and a wider application range.

In the optical system, the third lens 3 has a third image side surface S6, the third image side surface S6 has a radius of curvature R6 in a y-axis direction of a plane perpendicular to the optical axis 11, the fifth lens 5 has a fifth image side surface S10, the fifth image side surface S10 has a radius of curvature R10 in the y-axis direction of a plane perpendicular to the optical axis 11, an effective focal length of the optical system in the y-axis direction of a plane perpendicular to the optical axis 11 is fy, and the following formula is satisfied: -0.75 ≦ (R6-R10)/fy ≦ -0.5 indicating that the third image side surface S6 of the third lens 3 has less convexity than the fifth image side surface S10 of the fifth lens 5, and that the light rays pass through such that the spot is magnified by the first convergence at the third lens 3 and the second convergence at the fifth lens 5.

In this optical system, the seventh lens 7 has a seventh object-side surface S13 and a seventh image-side surface S14, and the seventh object-side surface S13 and the seventh image-side surface S14 are respectively centrosymmetric with respect to the optical axis 11.

Specifically, the on-axis distance from the intersection of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetrical about the y-axis, sag11 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance sag12 (x) from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh image-side surface S14; the distance from the intersection point of the seventh image-side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the y-axis of the effective radius vertex of the seventh image-side surface S14 is sag12 (y); sag12 (x) is symmetric about the y-axis, sag12 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

The seventh lens element 7 is disposed so that the seventh object-side surface S13 is centrosymmetric with respect to the optical axis 11, and the seventh image-side surface S14 incident on the seventh lens element 7 is centrosymmetric with respect to the optical axis 11, and the seventh image-side surface S14 is centrosymmetric with respect to the optical axis 11, so that an image formed on the image plane S17 is centered on the image plane S17 and is also centrosymmetric with respect to the optical axis 11.

Example 1

As shown in fig. 1, embodiment 1 of the present application provides an optical system having an object plane 8, an image plane S17, a stop 9, a filter 10, and a lens group composed of seven lenses, in which a first lens 1, a second lens 2, the stop 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and the filter 10 are arranged in this order from the object plane 8 to the image plane S17 in the direction of an optical axis 11. Wherein, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is | f1/ft | =7.328, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is | f2/ft | =37.864, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is | f3/ft | =1.473, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is | f4/ft | =3.717, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is | f5/ft | =1.058, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is | f6/ft | =4.654, and the ratio of the focal length f7 of the seventh lens group to the effective focal length ft of the lens group is | f7/ft =3.663.

Wherein, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens element 7 are both non-rotationally symmetric aspheric surfaces, and a maximum value TDT of TV distortion in an imaging range of the lens group satisfies | TDT | =2.20%.

The first lens 1 receives light from the object plane 8 and refracts the light to the second lens 2, and the range of the received light is the maximum field angle FOV of the lens group, and in the embodiment 1, FOV =122 ° is satisfied.

The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, which are the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction, respectively, and the ratio of the entrance pupil diameters EPD of the lens group to fx and fy is the F number Fno of the aperture, where Fno satisfies fx/EPD =2.0 and fy/EPD =2.0.

The distance from the first object side surface S1 of the first lens 1 of the lens group to the image surface S17 of the lens group on the optical axis 11 is total optical length TTL, and half of the diagonal length of the effective pixel area on the image surface S17 of the lens group is imgH, which satisfies TTL/imgH =1.34.

The curvature radius of a fifth object side surface S9 of the fifth lens 5 is R9, the curvature radius of a fifth image side surface S10 of the fifth lens 5 is R10, R9/R10=4.925 is satisfied, the middle thickness of the fifth lens 5 is far larger than the peripheral thickness, and the secondary convergence degree of light rays is enhanced.

The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, and R11/R12=1.595 is satisfied, and the sixth lens 6 appropriately diffuses and magnifies light rays.

The radius of curvature R13 of the seventh object-side surface S13 of the seventh lens element 7 and the radius of curvature R14 of the seventh image-side surface S14 of the seventh lens element 7 satisfy R13/R14=1.529, and the seventh lens element 7 performs appropriate diffusion magnification of the light beam and performs aberration correction of the light beam by a non-rotationally symmetric aspherical surface, thereby improving the quality of the image formed on the image plane S17.

The curvature radius R6 of the third image side surface S6 of the third lens 3 in the Y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the Y-axis direction perpendicular to the optical axis 11 and the effective focal length fy of the imaging lens in the Y-axis direction satisfy: (R6-R10)/fy = -0.588.

An on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetric about the y-axis, sag11 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh image-side surface S14 is sag12 (x); the distance from the intersection point of the seventh image-side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the y-axis of the effective radius vertex of the seventh image-side surface S14 is sag12 (y); sag12 (x) is symmetric about the y-axis, sag12 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

In the optical system of embodiment 1, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens 1, the second object-side surface S3 and the second image-side surface S4 of the second lens 2, the third object-side surface S5 and the third image-side surface S6 of the third lens 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens 6 are aspheric surfaces of Q type, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are aspheric surfaces of XY polynomial type that are not rotationally symmetric, the filter 10 has a certain thickness, and the filter object-side surface S15 and the filter image-side surface S16 are both planar, and the image plane S17 is planar.

The profile of the Q-type aspheric surface may satisfy, but is not limited to, the following aspheric surface formula:

wherein z is the rise of the aspheric surface, r is the radial coordinate of the aspheric surface, c is the vertex curvature of the aspheric surface, K is the conic constant, a _m Is an aspheric coefficient of r _max Is the maximum value of radial radius coordinate, u = r/r _max 。

wherein z is a rise parallel to the z-axis; n is the total number of polynomial coefficients in the series, ai is the coefficient of the ith expansion polynomial, r is the radial coordinate of the aspheric surface, c is the curvature of the aspheric vertex sphere, and K is a conic constant.

The basic parameters of the optical system of this example 1 are shown in tables 1a to 1d, where table 1a is the parameter of each surface, where R is the radius of curvature, th is the thickness of the surface, nd is the refractive index of the surface material, vd is the abbe number of the surface material, and f' is the focal length, all in millimeters (mm). Table 1b shows parameters of each lens element, where f1 to f7 are effective focal lengths of each lens element, TTL is total optical length of the optical system, half of diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, f-number of the optical imaging system is Fno, and effective focal length of the lens group is EFL. Table 1c shows aspheric parameters of each lens. Table 1d shows aspheric parameters of a lens having an aspheric surface that is not rotationally symmetric.

TABLE 1a

TABLE 1b

TABLE 1c

TABLE 1d

The optical system of this embodiment 1 is designed by using the basic parameters adopted in tables 1a to 1d, so as to form the architecture of the optical system shown in fig. 1, and the architecture makes full use of the mutual cooperation of positive and negative power transformation among seven lenses, and realizes an ultra-wide-angle and small-distortion ultra-wide-angle lens by the functions of aberration correction and distortion reduction of non-rotationally-symmetric aspheric surfaces on light. As shown in fig. 2, the distortion of the image of the object on the image plane S17 through the optical system of embodiment 1 is pincushion distortion, and the distortion is controlled to be within 2.20%. In fig. 2, the solid grid with a square and a positive square is an ideal image formed in an ideal state, and an image of an object corresponding to an intersection of the solid grid passing through the optical system of this embodiment 1 is a pixel point suspended around the solid grid, so that it can be seen that the actual image has pincushion distortion with respect to the solid grid, but the distortion degree is not large, and the pixel point is basically closely attached to the solid grid, thereby well achieving the purpose of this embodiment 1.

Example 2

As shown in fig. 3, embodiment 2 of the present application provides an optical system having an object plane 8, an image plane S17, a diaphragm 9, a filter 10, and a lens group composed of seven lenses, in which a first lens 1, a second lens 2, a diaphragm 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and a filter 10 are arranged in this order from the object plane 8 to the image plane S17 in the direction of an optical axis 11. Wherein, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is | f1/ft | =7.395, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is | f2/ft | =40.943, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is | f3/ft | =1.484, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is | f4/ft | =3.744, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is | f5/ft | =1.069, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is | f6/ft | =4.712, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is | f7/ft =3.202.

Wherein, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens element 7 are both non-rotationally symmetric aspheric surfaces, and a maximum value TDT of TV distortion in an imaging range of the lens group satisfies | TDT | =2.23%.

The first lens 1 receives light from the object plane 8 and refracts the light to the second lens 2, and the range of the received light is the maximum field angle FOV of the lens group, and in the embodiment 2, FOV =122 ° is satisfied.

The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, which are the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction, respectively, and the ratio of the entrance pupil diameters EPD of the lens group to fx and fy is the f-number Fno, where Fno satisfies fx/EPD =2.0 and fy/EPD =2.0.

The distance from the first object side surface S1 of the first lens 1 of the lens group to the image surface S17 of the lens group on the optical axis 11 is total optical length TTL, and half of the diagonal length of the effective pixel area on the image surface S17 of the lens group is imgH, which satisfies TTL/imgH =1.325.

The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, and R9/R10=4.873 is satisfied, and the middle thickness of the fifth lens 5 is much greater than the peripheral thickness, so that the secondary convergence degree of light rays is enhanced.

The sixth lens element 6 has a curvature radius of the sixth object-side surface S11 of R11 and a curvature radius of the sixth image-side surface S12 of R12 of the sixth lens element 6, and satisfies R11/R12=1.592, and the sixth lens element 6 appropriately diffuses and magnifies light rays.

The radius of curvature R13 of the seventh object-side surface S13 of the seventh lens element 7 and the radius of curvature R14 of the seventh image-side surface S14 of the seventh lens element 7 satisfy R13/R14=1.523, and the seventh lens element 7 appropriately diffuses and magnifies light beams and corrects the aberration of the light beams by a rotationally asymmetric aspheric surface, thereby improving the image quality formed on the image plane S17.

The curvature radius R6 of the third image side surface S6 of the third lens 3 in the Y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the Y-axis direction perpendicular to the optical axis 11 and the effective focal length fy of the imaging lens in the Y-axis direction satisfy: (R6-R10)/fy = -0.594.

An on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetrical about the y-axis, sag11 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh image-side surface S14 is sag12 (x); the distance from the intersection point of the seventh image-side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the y-axis of the effective radius vertex of the seventh image-side surface S14 is sag12 (y); sag12 (x) is symmetrical about the y-axis, sag12 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

In the optical system of embodiment 2, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens 1, the second object-side surface S3 and the second image-side surface S4 of the second lens 2, the third object-side surface S5 and the third image-side surface S6 of the third lens 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens 6 are aspheric surfaces of Q type, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are aspheric surfaces of XY polynomial type that are not rotationally symmetric, the filter 10 has a certain thickness, and the filter object-side surface S15 and the filter image-side surface S16 are both planar, and the image plane S17 is planar.

The surface shape of the Q-type aspheric surface can meet but is not limited to the following aspheric surface formula:

The non-rotationally symmetric aspherical surface shape of the seventh lens 7 is defined using the following aspherical surface formula:

wherein z is a rise parallel to the z-axis; n is the total number of polynomial coefficients in the series, ai is the coefficient of the ith expansion polynomial, r is the radial coordinate of the aspheric surface, c is the curvature of the aspheric surface vertex sphere, and K is a conic constant.

The basic parameters of the optical system of this example 2 are shown in tables 2a to 2d, where table 2a is the parameter of each surface, where R is the radius of curvature, th is the surface thickness, nd is the refractive index of the surface material, vd is the abbe number of the surface material, and f' is the focal length, and they are all expressed in millimeters (mm). Table 2b shows parameters of each lens, where f1 to f7 are effective focal lengths of each lens, TTL is a total optical length of the optical system, half of a diagonal length of an effective pixel area on the image plane S17 is ImgH, a maximum field of view is FOV, an f-number of the optical imaging system is Fno, and an effective focal length of the lens group is EFL. Table 2c shows aspheric parameters of each lens. Table 2d shows aspheric parameters of a lens having an aspheric surface that is not rotationally symmetric.

TABLE 2a

f1(mm)	-21.450	f2(mm)	-118.757	f3(mm)	4.305
						f4(mm)	-10.860	f5(mm)	3.099	f6(mm)	-13.667
f7(mm)	-9.288	TTL(mm)	6.889	Fno	2.090
						ImgH(mm)	5.200	FOV(°)	122	EFL	2.901

TABLE 2b

TABLE 2c

TABLE 2d

The optical system of this embodiment 2 is designed by using the basic parameters adopted in tables 2a to 2d, and the architecture of the optical system shown in fig. 3 is formed, and the architecture fully utilizes the mutual cooperation of positive and negative power transformation among seven lenses, and realizes an ultra-wide-angle and small-distortion ultra-wide-angle lens by the functions of aberration correction and distortion reduction of non-rotationally-symmetric aspheric surfaces on light. As shown in fig. 4, the distortion of the image of the object on the image plane S17 through the optical system of embodiment 2 is pincushion distortion, and the distortion is controlled to be within 2.23%. In fig. 4, the solid line grid with a square and a right square is an ideal image formed in an ideal state, and an image of an object corresponding to a cross point of the solid line grid passing through the optical system of this embodiment 2 is a pixel point suspended around the solid line grid, so that it can be seen that the actual image has pincushion distortion with respect to the solid line grid, but the distortion degree is not large, and the pixel point is basically closely attached to the solid line grid, thereby well achieving the purpose of this embodiment 2.

Example 3

As shown in fig. 5, embodiment 3 of the present application provides an optical system having an object plane 8, an image plane S17, a diaphragm 9, a filter 10, and a lens group composed of seven lenses, in which a first lens 1, a second lens 2, a diaphragm 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and a filter 10 are arranged in this order from the object plane 8 to the image plane S17 in the direction of an optical axis 11. Wherein, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is | f1/ft | =7.353, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is | f2/ft | =32.444, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is | f3/ft | =1.485, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is | f4/ft | =3.768, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is | f5/ft | =1.075, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is | f6/ft | =4.690, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is | f7/ft | =3.764.

Wherein, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens element 7 are both non-rotationally symmetric aspheric surfaces, and the maximum value TDT of TV distortion in the imaging range of the lens group satisfies | TDT | =2.12%.

The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, which are the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction, respectively, and the ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the f-number Fno, where Fno satisfies fx/EPD =2.0 and fy/EPD =2.0.

The distance from the first object side surface S1 of the first lens 1 of the lens group to the image surface S17 of the lens group on the optical axis 11 is total optical length TTL, and half of the diagonal length of the effective pixel area on the image surface S17 of the lens group is imgH, which satisfies TTL/imgH =1.551.

The curvature radius of the fifth object side surface S9 of the fifth lens 5 is R9, the curvature radius of the fifth image side surface S10 of the fifth lens 5 is R10, R9/R10=5.254 is satisfied, the middle thickness of the fifth lens 5 is far larger than the peripheral thickness, and the secondary convergence degree of the light rays is enhanced.

The radius of curvature of the sixth object-side surface S11 of the sixth lens element 6 is R11, the radius of curvature of the sixth image-side surface S12 of the sixth lens element 6 is R12, and R11/R12=1.598, and the sixth lens element 6 appropriately diffuses and magnifies light rays.

The radius of curvature R13 of the seventh object-side surface S13 of the seventh lens element 7 and the radius of curvature R14 of the seventh image-side surface S14 of the seventh lens element 7 satisfy R13/R14=1.524, and the seventh lens element 7 performs appropriate diffusion magnification of the light beam and performs aberration correction of the light beam by a non-rotationally symmetric aspherical surface, thereby improving the quality of the image formed on the image plane S17.

The curvature radius R6 of the third image side surface S6 of the third lens 3 in the Y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the Y-axis direction perpendicular to the optical axis 11 and the effective focal length fy of the imaging lens in the Y-axis direction satisfy: (R6-R10)/fy = -0.585.

An on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetrical about the y-axis, sag11 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh image-side surface S14 is sag12 (x); the distance from the intersection point of the seventh image-side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the y-axis of the effective radius vertex of the seventh image-side surface S14 is sag12 (y); sag12 (x) is symmetric about the y-axis, sag12 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

In the optical system of embodiment 3, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens 1, the second object-side surface S3 and the second image-side surface S4 of the second lens 2, the third object-side surface S5 and the third image-side surface S6 of the third lens 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens 6 are aspheric surfaces of Q type, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are aspheric surfaces of XY polynomial type that are not rotationally symmetric, the filter 10 has a certain thickness, and the filter object-side surface S15 and the filter image-side surface S16 are both planar, and the image plane S17 is planar.

wherein z is the rise of the aspheric surface, r is the radial coordinate of the aspheric surface, and c isAspheric vertex curvature, K is the conic constant, a _m Is an aspheric coefficient of r _max U = r/r as maximum radial radius coordinate _max 。

The basic parameters of the optical system of this example 3 are shown in tables 3a to 3d, where table 3a is the parameter of each surface, where R is the radius of curvature, th is the thickness of the surface, nd is the refractive index of the surface material, vd is the abbe number of the surface material, and f' is the focal length, all in millimeters (mm). Table 3b shows the parameters of each lens, where f1 to f7 are the effective focal length of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the f-number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 3c shows aspheric parameters of each lens. Table 3d shows aspheric parameters of a lens having an aspheric surface that is not rotationally symmetric.

TABLE 3a

f1(mm)	-24.571	f2(mm)	-108.420	f3(mm)	4.962
						f4(mm)	-12.593	f5(mm)	3.594	f6(mm)	-15.674
f7(mm)	-12.578	TTL(mm)	8.063	Fno	2.043
						ImgH(mm)	5.200	FOV(°)	122	EFL	3.342

TABLE 3b

TABLE 3c

TABLE 3d

The optical system of this embodiment 3 is designed by using the basic parameters in tables 3a to 3d, and the optical system architecture shown in fig. 5 is formed, and the optical system architecture fully utilizes the mutual cooperation of positive and negative power conversion among seven lenses, and realizes an ultra-wide-angle and small-distortion ultra-wide-angle lens by the functions of aberration correction and distortion reduction of non-rotationally symmetric aspheric surfaces on light. As shown in fig. 6, the distortion of the image of the object on the image plane S17 through the optical system of this embodiment 3 is pincushion distortion, and the distortion is controlled to be within 2.12%. In fig. 6, the solid line grid with a square and a right square is an ideal image formed in an ideal state, and an image of an object corresponding to a cross point of the solid line grid passing through the optical system of this embodiment 3 is a pixel point suspended around the solid line grid, so that it can be seen that the actual image has pincushion distortion with respect to the solid line grid, but the distortion degree is not large, and the pixel point is basically closely attached to the solid line grid, thereby well achieving the purpose of this embodiment 3.

Example 4

As shown in fig. 7, embodiment 4 of the present application provides an optical system having an object plane 8, an image plane S17, a diaphragm 9, a filter 10, and a lens group composed of seven lenses, in which a first lens 1, a second lens 2, a diaphragm 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and a filter 10 are arranged in this order from the object plane 8 to the image plane S17 in the direction of an optical axis 11. Wherein, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is | f1/ft | =7.389, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is | f2/ft | =26.075, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is | f3/ft | =1.568, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is | f4/ft | =3.978, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is | f5/ft | =1.106, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is | f6/ft | =5.897, and the ratio of the focal length f7 of the lens group to the effective focal length ft of the seventh lens group is | f7/ft | =4.527 |.527.

Wherein, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens element 7 are both non-rotationally symmetric aspheric surfaces, and the maximum value TDT of TV distortion in the imaging range of the lens group satisfies | TDT | =2.88%.

The first lens 1 receives light from the object plane 8 and refracts the light to the second lens 2, which is located behind the object plane, and the range of the received light is the maximum field angle FOV of the lens assembly, and in this embodiment 1, FOV =130 ° is satisfied.

The distance from the first object side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is total optical length TTL, half of the diagonal length of an effective pixel area on the image plane S17 of the lens group is ImgH, and TTL/ImgH =1.211 is met.

The curvature radius of the fifth object side surface S9 of the fifth lens 5 is R9, the curvature radius of the fifth image side surface S10 of the fifth lens 5 is R10, R9/R10=4.82 is satisfied, the middle thickness of the fifth lens 5 is far larger than the peripheral thickness, and the secondary convergence degree of the light rays is enhanced.

The radius of curvature of the sixth object-side surface S11 of the sixth lens element 6 is R11, the radius of curvature of the sixth image-side surface S12 of the sixth lens element 6 is R12, and R11/R12=1.493, and the sixth lens element 6 appropriately spreads and magnifies the light.

The radius of curvature R13 of the seventh object-side surface S13 of the seventh lens element 7 and the radius of curvature R14 of the seventh image-side surface S14 of the seventh lens element 7 satisfy R13/R14=1.463, and the seventh lens element 7 appropriately diffuses and magnifies light beams and corrects the aberration of the light beams by a rotationally asymmetric aspheric surface, thereby improving the image quality formed on the image plane S17.

The curvature radius R6 of the third image side surface S6 of the third lens 3 in the Y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the Y-axis direction perpendicular to the optical axis 11 and the effective focal length fy of the imaging lens in the Y-axis direction satisfy: (R6-R10)/fy = -0.630.

An on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetrical about the y-axis, sag11 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance sag12 (x) from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh image-side surface S14; the distance from the intersection point of the seventh image-side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the y-axis of the effective radius vertex of the seventh image-side surface S14 is sag12 (y); sag12 (x) is symmetrical about the y-axis, sag12 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

In the optical system of this embodiment 4, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens element 1, the second object-side surface S3 and the second image-side surface S4 of the second lens element 2, the third object-side surface S5 and the third image-side surface S6 of the third lens element 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens element 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens element 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens element 6 are aspheric surfaces of Q type, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens element 7 are aspheric surfaces of XY polynomial type that are not rotationally symmetric, the optical filter 10 has a certain thickness, the filter object-side surface S15 and the filter image-side surface S16 are both planes, and the image plane S17 is a plane.

The basic parameters of the optical system of this example 4 are shown in tables 4a to 4d, where table 4a is the parameter of each surface, where R is the radius of curvature, th is the surface thickness, nd is the refractive index of the surface material, vd is the abbe number of the surface material, and f' is the focal length, and they are all expressed in millimeters (mm). Table 4b shows parameters of each lens, where f1 to f7 are effective focal lengths of each lens, TTL is total optical length of the optical system, half diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the f-number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 4c shows aspheric parameters of each lens. Table 4d shows aspheric parameters for lenses having non-rotationally symmetric aspheric surfaces.

TABLE 4a

f1(mm)	-18.486	f2(mm)	-65.239	f3(mm)	3.923
						f4(mm)	-9.952	f5(mm)	2.768	f6(mm)	-14.754
f7(mm)	-11.327	TTL(mm)	6.295	Fno	2.073
						ImgH(mm)	5.200	FOV(°)	130	EFL	2.502

TABLE 4b

TABLE 4c

TABLE 4d

The optical system of this embodiment 4 is designed by using the basic parameters adopted in tables 4a to 4d, and the architecture of the optical system shown in fig. 7 is formed, and the architecture fully utilizes the mutual cooperation of positive and negative power transformation among seven lenses, and realizes an ultra-wide-angle and small-distortion ultra-wide-angle lens by the functions of aberration correction and distortion reduction of non-rotationally-symmetric aspheric surfaces on light. As shown in fig. 8, the distortion of the image of the object on the image plane S17 through the optical system of embodiment 4 is pincushion distortion, and the distortion is controlled to be within 2.88%. In fig. 8, the solid grid with a square and a positive square is an ideal image formed in an ideal state, and an image of an object corresponding to an intersection of the solid grid passing through the optical system of this embodiment 4 is a pixel point suspended around the solid grid, so that it can be seen that the actual image has pincushion distortion with respect to the solid grid, but the distortion degree is not large, and the pixel point is basically closely attached to the solid grid, thereby well achieving the purpose of this embodiment 4.

Example 5

As shown in fig. 9, embodiment 5 of the present application provides an optical system having an object plane 8, an image plane S17, a stop 9, a filter 10, and a lens group composed of seven lenses, in which a first lens 1, a second lens 2, the stop 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and the filter 10 are arranged in this order from the object plane 8 to the image plane S17 in the direction of an optical axis 11. Wherein, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is | f1/ft | =7.508, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is | f2/ft | =42.385, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is | f3/ft | =1.486, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is | f4/ft | =3.767, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is | f5/ft | =1.074, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is | f6/ft | =4.738, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is | f7/ft | =3.769.

Wherein, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens element 7 are both non-rotationally symmetric aspheric surfaces, and the maximum value TDT of TV distortion in the imaging range of the lens group satisfies | TDT | =1.11%.

The first lens 1 receives light from the object plane 8 and refracts the light to the second lens 2, and the range of the received light is the maximum field angle FOV of the lens group, and in the embodiment 5, FOV =110 ° is satisfied.

The distance from the first object side surface S1 of the first lens 1 of the lens group to the image surface S17 of the lens group on the optical axis 11 is total optical length TTL, and half of the diagonal length of an effective pixel area on the image surface S17 of the lens group is ImgH, so that TTL/ImgH =1.697 is met.

The curvature radius of the fifth object-side surface S9 of the fifth lens element 5 is R9, the curvature radius of the fifth image-side surface S10 of the fifth lens element 5 is R10, and R9/R10=4.923, and the middle thickness of the fifth lens element 5 is much greater than the peripheral thickness, so that the secondary convergence of light rays is enhanced.

The radius of curvature of the sixth object-side surface S11 of the sixth lens element 6 is R11, the radius of curvature of the sixth image-side surface S12 of the sixth lens element 6 is R12, and R11/R12=1.591, and the sixth lens element 6 appropriately diffuses and magnifies light rays.

The radius of curvature R13 of the seventh object-side surface S13 of the seventh lens element 7 and the radius of curvature R14 of the seventh image-side surface S14 of the seventh lens element 7 satisfy R13/R14=1.520, and the seventh lens element 7 appropriately diffuses and magnifies the light beam and corrects the aberration of the light beam by a rotationally asymmetric aspheric surface, thereby improving the image quality formed on the image plane S17.

The curvature radius R6 of the third image side surface S6 of the third lens 3 in the Y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the Y-axis direction perpendicular to the optical axis 11 and the effective focal length fy of the imaging lens in the Y-axis direction satisfy: (R6-R10)/fy = -0.595.

An on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetric about the y-axis, sag11 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh image-side surface S14 is sag12 (x); the distance from the intersection point of the seventh image-side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the y-axis of the effective radius vertex of the seventh image-side surface S14 is sag12 (y); sag12 (x) is symmetric about the y-axis, sag12 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

In the optical system of this embodiment 5, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens 1, the second object-side surface S3 and the second image-side surface S4 of the second lens 2, the third object-side surface S5 and the third image-side surface S6 of the third lens 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens 6 are aspheric surfaces of Q type, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are aspheric surfaces of XY polynomial type that are not rotationally symmetric, the filter 10 has a certain thickness, and the filter object-side surface S15 and the filter image-side surface S16 are both planar, and the image plane S17 is planar.

wherein z is the rise of the aspheric surface, r is the radial coordinate of the aspheric surface, c is the vertex curvature of the aspheric surface, K is a conic constant, a _m Is an aspheric coefficient, r _max U = r/r as maximum radial radius coordinate _max 。

The basic parameters of the optical system of this example 5 are shown in tables 5a to 5d, where table 5a is the parameter of each surface, where R is the radius of curvature, th is the surface thickness, nd is the refractive index of the surface material, vd is the abbe number of the surface material, and f' is the focal length, all in millimeters (mm). Table 5b shows the parameters of each lens element, where f1 to f7 are the effective focal length of each lens element, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the f-number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 5c shows aspheric parameters of each lens. Table 5d shows aspheric parameters for lenses having non-rotationally symmetric aspheric surfaces.

TABLE 5a

f1(mm)	-27.464	f2(mm)	-155.035	f3(mm)	5.436
						f4(mm)	-13.777	f5(mm)	3.929	f6(mm)	-17.332
f7(mm)	-13.787	TTL(mm)	8.825	Fno	2.081
						ImgH(mm)	5.200	FOV(°)	110	EFL	3.658

TABLE 5b

TABLE 5c

TABLE 5d

The optical system of this embodiment 5 is designed by using the basic parameters adopted in tables 5a to 5d, and the architecture of the optical system shown in fig. 9 is formed, and the architecture fully utilizes the mutual cooperation of positive and negative power transformation among seven lenses, and realizes an ultra-wide-angle and small-distortion ultra-wide-angle lens by the functions of aberration correction and distortion reduction of non-rotationally-symmetric aspheric surfaces on light. As shown in fig. 10, the distortion of the image of the object on the image plane S17 through the optical system of embodiment 5 is pincushion distortion, and the distortion is controlled to be within 1.11%. In fig. 10, the solid line grid with a square and a right square is an ideal image formed in an ideal state, and an image of an object corresponding to a cross point of the solid line grid passing through the optical system of this embodiment 5 is a pixel point suspended around the solid line grid, and it can be seen that the actual image has pincushion distortion with respect to the solid line grid, but the distortion degree is not large, and the pixel point is basically closely attached to the solid line grid, thereby well achieving the purpose of this embodiment 5.

Example 6

As shown in fig. 11, embodiment 6 of the present application provides an optical system having an object plane 8, an image plane S17, a diaphragm 9, a filter 10, and a lens group composed of seven lenses, in which a first lens 1, a second lens 2, a diaphragm 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and a filter 10 are arranged in this order from the object plane 8 to the image plane S17 in the direction of an optical axis 11. Wherein, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is | f1/ft | =6.551, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is | f2/ft | =17.832, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is | f3/ft | =1.890, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is | f4/ft | =3.886, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is | f5/ft | =1.361, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is | f6/ft | =4.528, and the ratio of the focal length f7 of the seventh lens group to the effective focal length ft of the lens group is | f7/ft = | f 3/867 | =3.867.

Wherein, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens element 7 are both non-rotationally symmetric aspheric surfaces, and the maximum value TDT of TV distortion in the imaging range of the lens group satisfies | TDT | =2.91%.

The first lens 1 receives light from the object plane 8 and refracts the light to the second lens 2, and the range of the received light is the maximum field angle FOV of the lens group, and in the embodiment 6, FOV =122 ° is satisfied.

The distance from the first object side surface S1 of the first lens 1 of the lens group to the image surface S17 of the lens group on the optical axis 11 is total optical length TTL, and half of the diagonal length of the effective pixel area on the image surface S17 of the lens group is imgH, which satisfies TTL/imgH =1.284.

The curvature radius of the fifth object side surface S9 of the fifth lens 5 is R9, the curvature radius of the fifth image side surface S10 of the fifth lens 5 is R10, R9/R10=5.651 is met, the middle thickness of the fifth lens 5 is far larger than the peripheral thickness, and the secondary convergence degree of the light rays is enhanced.

The radius of curvature of the sixth object-side surface S11 of the sixth lens element 6 is R11, the radius of curvature of the sixth image-side surface S12 of the sixth lens element 6 is R12, and R11/R12=0.535, and the sixth lens element 6 appropriately diffuses and magnifies light rays.

The radius of curvature R13 of the seventh object-side surface S13 of the seventh lens element 7 and the radius of curvature R14 of the seventh image-side surface S14 of the seventh lens element 7 satisfy R13/R14=1.635, and the seventh lens element 7 appropriately diffuses and magnifies the light beam and corrects the aberration of the light beam by a non-rotationally symmetric aspherical surface, thereby improving the quality of the image formed on the image plane S17.

The curvature radius R6 of the third image side surface S6 of the third lens 3 in the Y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the Y-axis direction perpendicular to the optical axis 11 and the effective focal length fy of the imaging lens in the Y-axis direction satisfy: (R6-R10)/fy = -0.704.

An on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh object-side surface S13 is sag11 (x); an on-axis distance from an intersection point of the seventh object-side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to a vertex of the effective radius of the seventh object-side surface S13 is sag11 (y); sag11 (x) is symmetrical about the y-axis, sag11 (y) is symmetrical about the x-axis, and the following conditions are satisfied: sag11 (x) = sag11 (-x), sag11 (y) = sag11 (-y). An on-axis distance from an intersection point of the seventh image-side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to a vertex of an effective radius of the seventh image-side surface S14 is sag12 (x); the distance sag12 (y) on the y-axis from the intersection point of the seventh image-side surface S14 and the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image-side surface S14; sag12 (x) is symmetric about the y-axis, sag12 (y) is symmetric about the x-axis, and the following conditions are satisfied: sag12 (x) = sag12 (-x), sag12 (y) = sag12 (-y).

In the optical system of this embodiment 6, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens element 1, the second object-side surface S3 and the second image-side surface S4 of the second lens element 2, the third object-side surface S5 and the third image-side surface S6 of the third lens element 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens element 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens element 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens element 6 are aspheric surfaces of Q type, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens element 7 are aspheric surfaces of XY polynomial type that are not rotationally symmetric, the optical filter 10 has a certain thickness, the filter object-side surface S15 and the filter image-side surface S16 are both planes, and the image plane S17 is a plane.

The basic parameters of the optical system of this example 6 are shown in tables 6a to 6d, where table 6a is the parameter of each surface, where R is the radius of curvature, th is the surface thickness, nd is the refractive index of the surface material, vd is the abbe number of the surface material, and f' is the focal length, and they are all expressed in millimeters (mm). Table 6b shows the parameters of each lens element, where f1 to f7 are the effective focal length of each lens element, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the f-number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 6c shows aspheric parameters of each lens. Table 6d shows aspheric parameters of lenses having non-rotationally symmetric aspheric surfaces.

TABLE 6a

f1(mm)	-16.683	f2(mm)	-45.410	f3(mm)	4.813
						f4(mm)	-9.896	f5(mm)	3.467	f6(mm)	11.532
f7(mm)	-9.848	TTL(mm)	6.675	Fno	2.159
						ImgH(mm)	5.200	FOV(°)	122	EFL	2.547

TABLE 6b

TABLE 6c

TABLE 6d

The optical system of this embodiment 6 is designed by using the basic parameters adopted in tables 6a to 6d, and the architecture of the optical system shown in fig. 11 is formed, and the architecture makes full use of the mutual cooperation of positive and negative power transformation among seven lenses, and realizes an ultra-wide-angle and small-distortion ultra-wide-angle lens by the functions of aberration correction and distortion reduction of non-rotationally-symmetric aspheric surfaces on light. As shown in fig. 12, the distortion of the image of the object on the image plane S17 through the optical system of this embodiment 6 is barrel distortion, and the distortion is controlled to be within-2.91%. In fig. 12, the solid grid with square and positive squares is an ideal image formed in an ideal state, and an image of an object corresponding to the intersection of the solid grid passing through the optical system of this embodiment 6 is a pixel point suspended around the solid grid, and it can be seen that the actual image has barrel distortion with respect to the solid grid, but the distortion degree is not large, and the pixel point is basically closely attached to the solid grid, thereby achieving the purpose of this embodiment 6 well.

Example 7

Embodiment 7 of the present application provides an image capturing apparatus, which includes the optical system provided in any one of embodiments 1 to 6. The image capturing device can be a camera module, an infrared camera module, and the like. By arranging the optical system in the image capturing device, the length of a lens of the image capturing device can be shortened, the field angle is increased and the distortion is reduced under the condition that the imaging size of the image surface S17 is basically unchanged, and the image capturing device combining an ultra-wide angle and small distortion is realized.

Example 8

Embodiment 8 of the present application provides a terminal device, which includes the image capturing apparatus provided in embodiment 7. By arranging the image capturing device with the optical system in the terminal equipment, various shooting application scenes under different large view fields can be realized, the function of the terminal equipment is enhanced, and the user experience is improved. The terminal equipment can be mobile phones, tablet computers and other equipment.

Therefore, in each aspect, by introducing the non-rotationally symmetric aspheric lens into the optical system, the design freedom is increased, the imaging quality of the lens under a compact system is improved, the imaging effect of ultra-wide angle and small distortion is realized, the distortion correction is performed without an algorithm in scenes such as video recording and shooting preview, and the method can be used for terminal equipment to shoot and record images, for example, scenes of external videos and photos are shot by using the lens of portable electronic products such as mobile phones, tablet computers and monitors, and various shooting application scenes under different large view fields are included.

Claims

1. An optical system, comprising: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are sequentially arranged from an object plane to an image plane along the optical axis direction;

the first lens, the second lens, the fourth lens, and the seventh lens have negative optical power;

the third lens and the fifth lens have positive optical power;

the sixth lens has optical power;

wherein at least one of the first lens, the second lens, the fourth lens, the sixth lens, and the seventh lens has a non-rotationally symmetric aspheric surface;

the third lens has a third image side surface having a radius of curvature R6 in a y-axis direction of a plane perpendicular to the optical axis, the fifth lens has a fifth image side surface having a radius of curvature R10 in the y-axis direction of a plane perpendicular to the optical axis, and an effective focal length of the optical system in the y-axis direction of a plane perpendicular to the optical axis is fy, which satisfies the following formula: -0.75< (R6-R10)/fy < -0.5;

the total optical length of the optical system is TTL, and half of the length of a diagonal line of an imaging area on the image surface is ImgH, which satisfies the following formula: TTL/ImgH is less than or equal to 1.7.

2. The optical system of claim 1, wherein the non-rotationally symmetric aspheric surface is disposed on the seventh lens.

3. The optical system of claim 1, wherein the TV distortion of the image formed by the optical system on the image plane is TDT, which satisfies the following equation: the absolute TDT is less than or equal to 3.0 percent.

4. The optical system of claim 1, wherein the optical system forms a maximum range of an image on the image plane, the length in the x direction is Imgx, the length in the y direction is Imgy, and the half-image height of the image is Imgy/Imgx, which satisfies the following equation: imgy/Imgx =0.75.

5. The optical system of claim 1, wherein the optical system has a field of view angle FOV that satisfies the following formula: FOV is more than or equal to 100 degrees and less than or equal to 130 degrees.

6. The optical system of claim 1 wherein an optical stop is disposed between the second lens and the third lens.

7. The optical system as claimed in claim 1, wherein the fifth lens element has a fifth object-side surface and a fifth image-side surface, the fifth object-side surface has a fifth object-side edge away from the optical axis and a fifth object-side center located on the optical axis, the fifth image-side surface has a fifth image-side edge away from the optical axis and a fifth image-side center located on the optical axis, the fifth object-side surface and the fifth image-side surface are curved toward the object plane with respect to the fifth object-side center and the fifth image-side center, respectively, the fifth object-side center and the fifth image-side center are convex toward the image plane with respect to the fifth object-side edge and the fifth image-side edge, respectively, a radius of curvature R9 of the fifth object-side surface is greater than a radius of curvature R10 of the fifth image-side surface, and a relationship of 4.7 ≦ R9/R10 ≦ 5.7 is satisfied.

8. The optical system as claimed in claim 1, wherein the sixth lens element has a sixth object-side surface and a sixth image-side surface, the sixth object-side surface has a sixth object-side edge far away from the optical axis and a sixth object-side center on the optical axis, the sixth image-side surface has the sixth image-side edge far away from the optical axis and a sixth image-side center on the optical axis, a region of the sixth object-side surface close to the sixth object-side edge and a region of the sixth image-side surface close to the sixth image-side edge are respectively curved toward the object plane, both the sixth object-side center and the sixth image-side center are convex toward the object plane, and an effective focal length f6 of the sixth lens element and an effective focal length fx of the optical system in the x-axis direction satisfy-6.5 ≦ f6/fx ≦ 5.5.

9. The optical system as claimed in claim 1, wherein the seventh lens element has a seventh object-side surface and a seventh image-side surface, the seventh object-side surface has a seventh object-side edge far away from the optical axis and a seventh object-side center on the optical axis, the seventh image-side surface has a seventh image-side edge far away from the optical axis and a seventh image-side center on the optical axis, a region of the seventh object-side surface close to the seventh object-side edge and a region of the seventh image-side surface close to the seventh image-side edge are respectively curved toward the image plane, the seventh object-side center and the seventh image-side center are both convex toward the object plane, and a radius of curvature R13 of the seventh object-side surface and a radius of curvature R14 of the seventh image-side surface satisfy 1.4 ≦ R13/R14 ≦ 1.7.

10. The optical system as claimed in claim 1, wherein the optical system has an effective focal length fx in an x-axis direction of a plane perpendicular to the optical axis, an effective focal length fy in a y-axis direction of the plane perpendicular to the optical axis, and an entrance pupil diameter EPD, which satisfy the following equations: fx/EPD =2.0, fy/EPD =2.0.

11. The optical system of claim 1, wherein the seventh lens has a seventh object side surface and a seventh image side surface, the seventh object side surface and the seventh image side surface each being centrosymmetric about the optical axis.

12. An image-taking apparatus comprising the optical system as claimed in any one of claims 1 to 11.

13. A terminal equipment, characterized by comprising the image capturing device as claimed in claim 12.