Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses in sequence along an optical axis from an object side to an imaging surface, and the eight lenses comprise: a first lens with negative optical power, wherein an image side of the first lens is a concave surface; a second lens with negative optical power, wherein an object side of the second lens is a convex surface, and an image side of the second lens is a concave surface; a third lens with positive optical power, wherein an object side of the third lens is a convex surface, and an image side of the third lens is a concave surface; a fourth lens with positive optical power, wherein an image side of the fourth lens is a convex surface; a fifth lens with positive optical power, wherein an image side of the fifth lens is a convex surface; a sixth lens with negative optical power, wherein an object side and an image side of the sixth lens are both concave surfaces; a seventh lens with positive optical power, wherein an object side of the seventh lens is a concave surface, and an image side of the seventh lens is a convex surface; and an eighth lens with negative optical power, wherein an object side of the eighth lens is a convex surface, and an image side of the eighth lens is a concave surface. The optical lens provided by the application improves the imaging quality of the optical lens, reduces aberration and improves the imaging quality of the optical lens through reasonable configuration of the surface type of each lens and reasonable matching of optical power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lenses, in particular to an optical lens. BACKGROUND

[0002] With the continuous development of existing image processing algorithms and AI technology, optical lenses are widely used in action cameras, vehicle-mounted lenses, smart homes and other fields. However, the optical lens of the existing action camera still has many shortcomings in underwater imaging, such as the decline of imaging quality, poor light transmission performance, and the inability to adapt to dark environments, and the existing lens imaging target surface is small, which is difficult to meet market demand.

[0003] Therefore, it is necessary to develop an optical lens with one or more advantages of ultra-wide angle, high imaging quality, high pixels, etc., so as to better meet the high demand of the market for underwater lenses. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an optical lens with one or more advantages of ultra-wide angle, high pixels, high imaging quality, etc.

[0005] The present application provides an optical lens, which comprises eight lenses in order along the optical axis from the object side to the imaging surface:

[0006] The first lens with negative focal power has a concave image side surface;

[0007] The second lens with negative focal power has a convex object side surface and a concave image side surface;

[0008] The third lens with positive focal power has a convex object side surface and a concave image side surface;

[0009] The fourth lens with positive focal power has a convex image side surface;

[0010] The fifth lens with positive focal power has a convex image side surface;

[0011] The sixth lens with negative focal power has a concave object side surface and a concave image side surface;

[0012] The seventh lens with positive focal power has a concave object side surface and a convex image side surface;

[0013] The eighth lens with negative focal power has a convex object side surface and a concave image side surface;

[0014] Wherein, the image side surface curvature radius R6 of the third lens and the object side surface curvature radius R13 of the seventh lens satisfy: R6 / R13<-0.1.

[0015] It is further preferred that the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 50°<FOV / Fno<70°.

[0016] It is further preferred that the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: BFL / f>1.

[0017] It is further preferred that the maximum field of view FOV of the optical lens, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 35°<FOVxf / IH<55°.

[0018] It is further preferred that the effective focal length f of the optical lens and the image-side surface curvature radius R6 of the third lens satisfy: R6 / f>2.

[0019] It is further preferred that the effective focal length f of the optical lens and the object-side surface curvature radius R13 of the seventh lens satisfy: -11<R13 / f<-6.

[0020] It is further preferred that the focal length f3 of the third lens and the object-side surface curvature radius R5 of the third lens satisfy: 0.1<R5 / f3<1.5; and the focal length f3 of the third lens and the image-side surface curvature radius R6 of the third lens satisfy: R6 / f3>0.1.

[0021] It is further preferred that the focal length f7 of the seventh lens and the object-side surface curvature radius R13 of the seventh lens satisfy: -5.5<R13 / f7<-3.3; and the focal length f7 of the seventh lens and the image-side surface curvature radius R14 of the seventh lens satisfy: -0.7<R14 / f7<-0.2.

[0022] It is further preferred that the object-side surface curvature radius R5 of the third lens and the image-side surface curvature radius R6 of the third lens satisfy: -1<(R5-R6) / (R5+R6)<0.

[0023] It is further preferred that the object-side surface curvature radius R13 of the seventh lens and the image-side surface curvature radius R14 of the seventh lens satisfy: 0<(R13-R14) / (R13+R14)<1.

[0024] The optical lens provided by the present application improves the imaging quality of the optical lens, reduces aberration, and improves the imaging quality of the optical lens by reasonable configuration of each lens surface and reasonable matching of optical power, so that the lens has one or more advantages such as super wide angle, high pixel, and high imaging quality. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0026] Figure 1 A structure schematic diagram of an optical lens in Embodiment 1 of the present application.

[0027] Figure 2 A field curvature curve diagram of the optical lens in Embodiment 1 of the present application.

[0028] Figure 3 An F-θ distortion curve diagram of the optical lens in Embodiment 1 of the present application.

[0029] Figure 4 A sagittal chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present application.

[0030] Figure 5 An axial aberration curve diagram of the optical lens in Embodiment 1 of the present application.

[0031] Figure 6 An MTF curve diagram of the optical lens in Embodiment 1 of the present application.

[0032] Figure 7 A structure schematic diagram of an optical lens in Embodiment 2 of the present application.

[0033] Figure 8 A field curvature curve diagram of the optical lens in Embodiment 2 of the present application.

[0034] Figure 9 An F-θ distortion curve diagram of the optical lens in Embodiment 2 of the present application.

[0035] Figure 10 A sagittal chromatic aberration curve diagram of the optical lens in Embodiment 2 of the present application.

[0036] Figure 11 An axial aberration curve diagram of the optical lens in Embodiment 2 of the present application.

[0037] Figure 12 An MTF curve diagram of the optical lens in Embodiment 2 of the present application.

[0038] Figure 13 A structure schematic diagram of an optical lens in Embodiment 3 of the present application.

[0039] Figure 14 A field curvature curve diagram of the optical lens in Embodiment 3 of the present application.

[0040] Figure 15 An F-θ distortion curve diagram of the optical lens in Embodiment 3 of the present application.

[0041] Figure 16A vertical color aberration curve of the optical lens in Embodiment 3 of the present application.

[0042] Figure 17 An axial aberration curve of the optical lens in Embodiment 3 of the present application.

[0043] Figure 18 An MTF curve of the optical lens in Embodiment 3 of the present application.

[0044] Figure 19 A structure diagram of the optical lens in Embodiment 4 of the present application.

[0045] Figure 20 A curvature of field curve of the optical lens in Embodiment 4 of the present application.

[0046] Figure 21 An F-theta distortion curve of the optical lens in Embodiment 4 of the present application.

[0047] Figure 22 A vertical color aberration curve of the optical lens in Embodiment 4 of the present application.

[0048] Figure 23 An axial aberration curve of the optical lens in Embodiment 4 of the present application.

[0049] Figure 24 An MTF curve of the optical lens in Embodiment 4 of the present application.

[0050] The following detailed description will further describe the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0051] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be noted that these detailed descriptions are only descriptions of embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, like drawing reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0052] It is to be noted that, in the present specification, the expressions first, second, third, etc. are used only to distinguish one feature from another feature, and do not indicate any limitation on the features. Thus, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0053] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical surface or the aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0054] In the present disclosure, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the imaging plane is referred to as the image side surface of the lens.

[0055] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when expressions such as "at least one of" appear after a list of two or more items, the phrase is intended to refer to any combination of one or more of the listed items, but not a single combination of one of the items. In addition, when describing embodiments of the present application, the word "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.

[0056] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that the terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0057] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0058] The optical lens provided by the embodiments of the present application comprises eight lenses, which are sequentially arranged along the optical axis from the object side to the imaging plane as the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens.

[0059] In some embodiments, the first lens can have a negative focal power, the object side surface can be a plane, a convex surface or a concave surface, and the image side surface is a concave surface. The second lens can have a negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface. The third lens can have a positive focal power, the object side surface is a convex surface, and the image side surface is a concave surface. The fourth lens can have a positive focal power, the object side surface can be a convex surface or a concave surface, and the image side surface is a convex surface. The fifth lens can have a positive focal power, the object side surface can be a convex surface or a concave surface, and the image side surface is a convex surface. The sixth lens can have a negative focal power, both the object side surface and the image side surface are concave surfaces. The seventh lens can have a positive focal power, the object side surface is a concave surface, and the image side surface is a convex surface. The eighth lens can have a negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface. The optical lens of the present application can realize lens imaging underwater and has good imaging effect.

[0060] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the fourth lens and the fifth lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging. In addition, when the diaphragm is located between the fourth lens and the fifth lens, the diaphragm can reasonably distribute the functions of the first lens to the eighth lens, for example, the first lens, the second lens, the third lens and the fourth lens can be used to receive light to a greater extent, and the fifth lens to the eighth lens can be used for the function of correcting aberration, which is conducive to balancing the structure of the entire optical system. In addition, when the diaphragm is located between the fourth lens and the fifth lens, the diaphragm aberration can be corrected.

[0061] In some embodiments, the optical lens can further comprise a filter, which is arranged between the eighth lens and the imaging surface. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0062] In some embodiments, the image side surface curvature radius R6 of the third lens and the object side surface curvature radius R13 of the seventh lens satisfy: R6 / R13 <-0.1. Satisfying the above range can reasonably control the shape of the image side surface of the third lens and the object side surface of the seventh lens, which is helpful to improve the aberration and improve the imaging quality. More specifically, the image side surface curvature radius R6 of the third lens and the object side surface curvature radius R13 of the seventh lens satisfy: -170 < R6 / R13 < -0.7.

[0063] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 50° < FOV / Fno < 70°. Satisfying the above range can limit the optical lens to have a suitable field of view and aperture value, which can collect light at a large angle and obtain good imaging quality. More specifically, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 56° < FOV / Fno < 62°.

[0064] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: BFL / f > 1. Satisfying the above range, the optical lens is limited to have a suitable back focus, the positions of the lenses are reasonably arranged, and the processing and assembling difficulty is reduced. More specifically, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 1 < BFL / f < 1.2.

[0065] In some embodiments, the maximum field of view FOV of the optical lens, the effective focal length f of the optical lens, and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 35° < FOVxf / IH < 55°. Satisfying the above range, the field of view, focal length and image height of the optical lens are limited to be within a reasonable range, which helps to balance the large field of view and large image surface, and improves the overall structural stability of the lens. More specifically, the maximum field of view FOV of the optical lens, the effective focal length f of the optical lens, and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 41° < FOVxf / IH < 47°.

[0066] In some embodiments, the effective focal length f of the optical lens and the image side surface curvature radius R6 of the third lens satisfy: R6 / f > 2. Satisfying the above range, the shape of the image side surface of the third lens is limited, which helps to reduce aberration and improve the imaging quality of the optical lens. More specifically, the effective focal length f of the optical lens and the image side surface curvature radius R6 of the third lens satisfy: R6 / f > 7.5.

[0067] In some embodiments, the effective focal length f of the optical lens and the object side surface curvature radius R13 of the seventh lens satisfy: -11 < R13 / f < -6. Satisfying the above range, the shape of the object side surface of the seventh lens is limited, which helps to reasonably control the light path, reduce the field curvature, and improve the imaging quality of the optical lens. More specifically, the effective focal length f of the optical lens and the object side surface curvature radius R13 of the seventh lens satisfy: -9.9 < R13 / f < -7.8.

[0068] In some embodiments, the focal length f3 of the third lens and the object side surface curvature radius R5 of the third lens satisfy: 0.1 < R5 / f3 < 1.5; the focal length f3 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: R6 / f3 > 0.1. Satisfying the above range, the ratio of the object side surface curvature radius and the image side surface curvature radius of the third lens to the focal length of the third lens is reasonably controlled, which helps to balance the high-order aberration of the front lens and reduce the aberration correction difficulty of the rear lens. More specifically, the focal length f3 of the third lens and the object side surface curvature radius R5 of the third lens satisfy: 0.4 < R5 / f3 < 0.9; the focal length f3 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.5 < R6 / f3 < 130.

[0069] In some embodiments, the focal length f7 of the seventh lens and the radius of curvature R13 of the object side surface of the seventh lens satisfy -5.5 < R13 / f7 < -3.3; the focal length f7 of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy -0.7 < R14 / f7 < -0.2. Satisfying the above ranges, the ratios of the radii of curvature of the object side surface and the image side surface of the seventh lens to the focal length of the seventh lens are reasonably controlled, which helps to reduce distortion and improve imaging quality. More specifically, the focal length f7 of the seventh lens and the radius of curvature R13 of the object side surface of the seventh lens satisfy -5 < R13 / f7 < -3.9; the focal length f7 of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy -0.5 < R14 / f7 < -0.4.

[0070] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy -1 < (R5-R6) / (R5+R6) < 0. Satisfying the above ranges, the shapes of the object side surface and the image side surface of the third lens are reasonably limited, which can control the third lens to have appropriate surface types, reasonably control the light ray trend, and improve imaging quality. More specifically, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy -1 < (R5-R6) / (R5+R6) < -0.3.

[0071] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy 0 < (R13-R14) / (R13+R14) < 1. Satisfying the above ranges, the shapes of the object side surface and the image side surface of the seventh lens are reasonably limited, which can control the seventh lens to have appropriate surface types, effectively improve field curvature and aberration, and improve imaging quality. More specifically, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy 0.7 < (R13-R14) / (R13+R14) < 0.9.

[0072] In some embodiments, the effective focal length f of the optical lens and the total track length TTL satisfy 6.5 < TTL / f < 12. Satisfying the above ranges, the relationship between the total track length and the focal length is reasonably controlled, and the design and optimization are performed in a reasonable space. More specifically, the effective focal length f of the optical lens and the total track length TTL satisfy 7.1 < TTL / f < 9.9.

[0073] In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view angle satisfy 3.1 < IH / f < 4.8. Satisfying the above ranges, the relationship between the image height and the focal length is reasonably controlled, which helps the optical lens to achieve high-pixel characteristics. More specifically, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view angle satisfy 3.5 < IH / f < 4.3.

[0074] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5.5 < f1 / f < -4. This satisfies the above range, which limits the first lens to have a proper negative optical power, and helps the optical lens to collect large-angle light rays, achieving a large field of view characteristic. More specifically, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5 < f1 / f < -4.6.

[0075] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -3.1 < f2 / f < -1.3. This satisfies the above range, which limits the second lens to have a proper negative optical power, and helps to balance the negative optical power of the front-end lens, reduces the generation of high-order aberrations, and facilitates the improvement of the subsequent lens on the imaging quality. More specifically, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.7 < f2 / f < -1.8.

[0076] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 6 < f3 / f < 14. This satisfies the above range, which limits the third lens to have a proper positive optical power, and helps to stabilize the light ray trend, improving the imaging quality. More specifically, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7.8 < f3 / f < 11.8.

[0077] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2 < f4 / f < 4.5. This satisfies the above range, which limits the fourth lens to have a proper positive optical power, and helps to converge light rays, making as many light rays as possible shoot towards the image plane. More specifically, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 2.5 < f4 / f < 3.9.

[0078] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.2 < f5 / f < 2.9. This satisfies the above range, which limits the fifth lens to have a proper positive optical power, and helps to reduce ghosting and improve the imaging quality. More specifically, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.8 < f5 / f < 2.2.

[0079] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -2.3 < f6 / f < -0.9. This satisfies the above range, which limits the sixth lens to have a proper negative optical power, and helps to increase the imaging area and improve the imaging quality. More specifically, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.9 < f6 / f < -1.5.

[0080] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.2 < f7 / f < 2.6. Satisfying the above range, the seventh lens is defined to have proper positive refractive power, which helps to optimize the spherical aberration, converge the marginal field rays, and improve the relative illumination of the lens. More specifically, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.7 < f7 / f < 2.

[0081] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -50 < f8 / f < -15. Satisfying the above range, the eighth lens is defined to have proper negative refractive power, which helps to increase the imaging area and improve the imaging quality. More specifically, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -45 < f8 / f < -21.

[0082] In some embodiments, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 1.5 < f1234 / f5678 < 14. Satisfying the above range, the front and rear lens groups of the optical lens are defined to have proper focal length ratio, so that the focal lengths of the lenses of the optical lens are reasonably divided, and the structural stability of the optical lens is improved. More specifically, the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 2.7 < f1234 / f5678 < 12.5.

[0083] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: 3 < R5 / f < 11. Satisfying the above range, the shape of the object side surface of the third lens is defined, which helps to reduce the field curvature and improve the imaging quality of the optical lens. More specifically, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: 3.6 < R5 / f < 9.1.

[0084] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: -1.5 < R14 / f < -0.3. Satisfying the above range, the shape of the image side surface of the seventh lens is defined, which helps to control the astigmatism and realize the high-pixel characteristics of the optical lens. More specifically, the effective focal length f of the optical lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: -1 < R14 / f < -0.8.

[0085] In some embodiments, the object-side half light aperture diameter d1 of the first lens and the image-side half light aperture diameter d8 of the fourth lens satisfy: 7 < d1 / d8 < 14; the object-side half light aperture diameter d9 of the fifth lens and the image-side half light aperture diameter d16 of the eighth lens satisfy: 0.1 < d9 / d16 < 0.5. Satisfying the above range and reasonably matching the aperture ratio of each lens, the structure design is facilitated, and the imaging quality of the optical lens is improved. More specifically, the object-side half light aperture diameter d1 of the first lens and the image-side half light aperture diameter d8 of the fourth lens satisfy: 8.5 < d1 / d8 < 12.5; the object-side half light aperture diameter d9 of the fifth lens and the image-side half light aperture diameter d16 of the eighth lens satisfy: 0.2 < d9 / d16 < 0.4.

[0086] In some embodiments, the distance CT12 between the first lens and the second lens on the optical axis and the distance CT23 between the second lens and the third lens on the optical axis satisfy: 0.5 < CT12 / CT23 < 3. Satisfying the above range, the air gap between the first lens and the second lens and the air gap between the second lens and the third lens are reasonably controlled, the processability of the lenses is maintained, and the lenses are reasonably arranged in the optical system. More specifically, the distance CT12 between the first lens and the second lens on the optical axis and the distance CT23 between the second lens and the third lens on the optical axis satisfy: 0.6 < CT12 / CT23 < 2.1.

[0087] In some embodiments, the optical lens satisfies the conditions: 2.8 mm < f < 4.2 mm, FOV > 150°, 0.8 mm < EPD < 1.5 mm, 25 mm < TTL < 35 mm, 2.6 < Fno < 3.2, 10 mm < IH < 18 mm, 7° < CRA < 22°, and 3 mm < BFL < 5 mm, where f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray angle of incidence at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Satisfying the above conditions indicates that the optical lens provided in the embodiments has at least the characteristics of super wide angle and large image surface.

[0088] In some embodiments, the material of the lenses in the optical lens provided in the embodiments can be glass or plastic. When the material of the lenses is plastic, the production cost can be effectively reduced. When the material of the lenses is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided in the embodiments can adopt a full-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0089] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt a spherical lens or an aspherical lens. Compared with a spherical structure, an aspherical structure can effectively reduce aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving miniaturization of the optical lens. More specifically, in the optical lens provided by the application, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt an aspherical lens, and the first lens can adopt a spherical lens.

[0090] In various embodiments of the application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0091]

[0092] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.

[0093] The application will be further described in the following embodiments. In various embodiments, the thickness, the radius of curvature, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are merely preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, and any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement modes, and are included in the protection scope of the application.

[0094] Embodiment 1

[0095] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens provided in Embodiment 1 of the application. The optical lens includes, in sequence along the optical axis from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a diaphragm ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0096] The first lens L1 has a negative focal power, and the object side surface S1 and the image side surface S2 thereof are concave surfaces.

[0097] The second lens L2 has a negative focal power, the object side surface S3 thereof is a convex surface, and the image side surface S4 thereof is a concave surface.

[0098] The third lens L3 has a positive focal power, the object side surface S5 thereof is a convex surface, and the image side surface S6 thereof is a concave surface.

[0099] The fourth lens L4 has positive refractive power, and both the object side S7 and the image side S8 are convex surfaces;

[0100] The fifth lens L5 has positive refractive power, and the object side S9 is a concave surface and the image side S10 is a convex surface;

[0101] The sixth lens L6 has negative refractive power, and both the object side S11 and the image side S12 are concave surfaces;

[0102] The seventh lens L7 has positive refractive power, and the object side S13 is a concave surface and the image side S14 is a convex surface;

[0103] The eighth lens L8 has negative refractive power, and the object side S15 is a convex surface and the image side S16 is a concave surface;

[0104] Both the object side S17 and the image side S18 of the filter G1 are flat surfaces;

[0105] The imaging surface S19 is a flat surface.

[0106] The first lens L1 is a glass spherical lens; the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are glass aspherical lenses.

[0107] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.

[0108] Table 1-1

[0109]

[0110]

[0111] The surface type parameters of the aspherical lenses of the optical lens in Embodiment 1 are shown in Table 1-2.

[0112] Table 1-2

[0113] Face number K B C D E F S3 2.24E+00 5.24E-04 -1.60E-05 7.43E-07 -1.63E-08 8.19E-11 S4 2.62E-01 -1.26E-03 -8.85E-05 4.14E-05 -6.09E-06 3.18E-07 S5 -5.10E+01 -2.32E-03 -2.76E-04 4.98E-05 -2.94E-06 2.57E-07 S6 -5.06E+01 5.90E-03 -2.29E-04 -1.34E-06 2.10E-06 1.19E-07 S7 -4.70E+01 1.48E-02 -3.49E-04 1.48E-04 -2.38E-05 2.02E-06 S8 -2.30E+01 -2.68E-03 1.46E-03 -1.91E-04 4.60E-05 -3.37E-06 S9 -5.09E+01 2.56E-03 -9.58E-04 3.47E-05 -2.16E-05 1.45E-06 S10 9.48E-02 7.74E-03 -1.04E-03 3.59E-05 -2.67E-07 -1.56E-07 S11 8.49E-01 5.36E-03 -1.61E-03 2.31E-04 -2.50E-05 1.37E-06 S12 3.31E+01 -4.46E-03 2.32E-04 -9.73E-06 5.01E-07 -1.20E-08 S13 4.17E+01 -3.12E-03 3.20E-04 -1.55E-05 5.09E-07 -6.72E-09 S14 -1.05E+00 -1.13E-03 2.29E-04 -1.66E-05 6.63E-07 -9.11E-09 S15 4.16E+00 -3.85E-03 2.14E-04 -6.20E-06 9.27E-08 -5.87E-10 S16 1.81E+00 -4.04E-03 1.77E-04 -4.32E-06 5.43E-08 -2.97E-10

[0114] In this embodiment, the field curvature curve, the F-theta distortion curve, the vertical axis chromatic aberration curve, the axial aberration curve and the MTF curve of the optical lens are shown in Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6

[0115] Figure 2 ​The field curvature curve of embodiment 1 is shown, which represents the curvature of light rays of different wavelengths on the meridional image surface and sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within-0.15mm~0.05mm, which shows that the optical lens can well correct the field curvature.

[0116] Figure 3 The F-θ distortion curve of embodiment 1 is shown, which represents the F-θ distortion of light rays of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-θ distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-θ distortion of the optical lens is controlled within 0~20%, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.

[0117] Figure 4 The axial chromatic aberration curve of embodiment 1 is shown, which represents the axial chromatic aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial chromatic aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial chromatic aberration is controlled within ±0.04mm, which shows that the optical lens can better correct the axial chromatic aberration.

[0118] Figure 5 The axial chromatic aberration curve of embodiment 1 is shown, which represents the axial chromatic aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial chromatic aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial chromatic aberration is controlled within ±0.04mm, which shows that the optical lens can better correct the axial chromatic aberration.

[0119] Figure 6 The MTF (Modulation Transfer Function) curve of embodiment 1 is shown, which represents the lens imaging modulation of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.35 in the full field of view, and in the range of 0~160lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in low frequency and high frequency conditions.

[0120] Embodiment 2

[0121] Please refer to Figure 7The figure shows a schematic diagram of the optical lens provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S9 of the fifth lens L5 is a convex surface; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0122] The relevant parameters of each lens in the optical lens of Example 2 are shown in Table 2-1.

[0123] Table 2-1

[0124]

[0125]

[0126] The surface profile parameters of the aspherical lens in Example 2 are shown in Table 2-2.

[0127] Table 2-2

[0128] Face number K B C D E F S3 -3.95E-01 5.11E-04 -1.56E-05 7.36E-07 -1.61E-08 7.64E-11 S4 2.43E-01 -1.36E-03 -7.04E-05 4.18E-05 -6.34E-06 3.57E-07 S5 -5.09E+01 -2.36E-03 -2.63E-04 4.99E-05 -2.79E-06 2.13E-07 S6 5.00E+01 5.96E-03 -2.29E-04 6.08E-07 2.13E-06 1.04E-07 S7 -1.51E+01 1.48E-02 -3.31E-04 1.39E-04 -2.39E-05 2.16E-06 S8 -2.21E+01 -2.74E-03 1.44E-03 -1.92E-04 4.41E-05 -2.49E-06 S9 -5.00E+01 2.42E-03 -8.69E-04 4.69E-05 -1.99E-05 1.10E-06 S10 9.82E-02 7.70E-03 -1.07E-03 3.59E-05 -1.58E-07 -1.17E-07 S11 8.47E-01 5.37E-03 -1.60E-03 2.31E-04 -2.49E-05 1.38E-06 S12 4.09E+01 -4.40E-03 2.29E-04 -9.80E-06 5.00E-07 -1.20E-08 S13 4.12E+01 -3.11E-03 3.22E-04 -1.56E-05 5.01E-07 -6.92E-09 S14 -1.01E+00 -1.16E-03 2.39E-04 -1.65E-05 6.61E-07 -9.23E-09 S15 5.12E+00 -4.02E-03 2.12E-04 -6.18E-06 9.24E-08 -5.93E-10 S16 7.43E-01 -4.27E-03 1.78E-04 -4.30E-06 5.45E-08 -2.94E-10

[0129] In this embodiment, the field curvature curve, F-θ distortion curve, transverse chromatic aberration curve, axial aberration curve, and MTF curve of the optical lens are respectively as follows: Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.

[0130] from Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.2mm to 0.05mm, indicating that the optical lens can effectively correct the field curvature.

[0131] from Figure 9 As can be seen, the F-θ distortion of the optical lens is controlled within 0 to 20%, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the unfolded image.

[0132] from Figure 10 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can correct the chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane very well.

[0133] from Figure 11 As can be seen, the axial aberration offset is controlled within ±0.03mm, indicating that the optical lens can effectively correct axial aberration.

[0134] from Figure 12It can be seen from the MTF curves in the full field of view that the MTF values of the optical lens provided in the embodiment are all above 0.4, the MTF curves are uniformly and smoothly decreased from the center to the edge of the field of view in the range of 0-160 lp / mm, and the optical lens has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.

[0135] Embodiment 3

[0136] Please refer to Figure 13 , which is a structural schematic diagram of the optical lens provided in Embodiment 3 of the present application. Compared with Embodiment 1, the main difference of the present embodiment is that the object side S1 of the first lens L1 is a convex surface, the object side S7 of the fourth lens L4 is a concave surface, and the object side S9 of the fifth lens L5 is a convex surface. The optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0137] The related parameters of each lens in the optical lens in Embodiment 3 are shown in Table 3-1.

[0138] Table 3-1

[0139]

[0140] The surface type parameters of the aspherical lens of the optical lens in Embodiment 3 are shown in Table 3-2.

[0141] Table 3-2

[0142]

[0143]

[0144] In the present embodiment, the field curvature curve, the F-θ distortion curve, the vertical axis chromatic aberration curve, the axial aberration curve and the MTF curve of the optical lens are shown in Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 respectively.

[0145] It can be seen from Figure 14 that the field curvature of the meridional image surface and the sagittal image surface is controlled within-0.15 mm-0.05 mm, which indicates that the optical lens can well correct the field curvature.

[0146] It can be seen from Figure 15 that the F-θ distortion of the optical lens is controlled within ± 15%, the image compression in the edge angle region is relatively flat, and the definition of the unfolded image is effectively improved.

[0147] It can be seen from Figure 16As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can correct the chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane very well.

[0148] from Figure 17 As can be seen, the axial aberration offset is controlled within ±0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0149] from Figure 18 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0150] Example 4

[0151] Please see Figure 19 The figure shows a schematic diagram of the optical lens provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the object side surface S1 of the first lens L1 is a plane; the object side surface S7 of the fourth lens L4 is a concave surface; the object side surface S9 of the fifth lens L5 is a convex surface; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0152] The relevant parameters of each lens in the optical lens of Example 4 are shown in Table 4-1.

[0153] Table 4-1

[0154]

[0155]

[0156] The surface profile parameters of the aspherical lens in Example 4 are shown in Table 4-2.

[0157] Table 4-2

[0158] Face number K B C D E F S3 -7.85E+00 2.88E-04 -2.19E-05 7.60E-07 -1.62E-08 9.72E-11 S4 8.04E-02 -2.09E-03 1.78E-05 2.56E-05 -3.14E-06 3.70E-07 S5 -1.79E+01 -2.13E-03 -3.47E-04 4.92E-05 -2.71E-06 4.37E-07 S6 1.84E+01 5.68E-03 -2.05E-04 -3.37E-05 1.27E-06 5.93E-07 S7 5.08E+01 1.78E-02 -7.94E-04 1.67E-04 -2.00E-05 9.15E-08 S8 -2.11E+01 -3.05E-03 1.28E-03 -1.93E-04 4.62E-05 -8.89E-06 S9 -5.03E+01 3.29E-03 -7.71E-04 -2.15E-05 -2.58E-05 -7.61E-07 S10 6.99E-02 9.00E-03 -1.13E-03 4.84E-05 -8.61E-07 -4.13E-07 S11 6.97E-01 5.36E-03 -1.55E-03 2.03E-04 -2.33E-05 1.34E-06 S12 -8.07E+00 -4.68E-03 2.38E-04 -1.19E-05 5.86E-07 3.10E-09 S13 -1.16E+01 -3.29E-03 3.20E-04 -1.77E-05 6.73E-07 -7.57E-09 S14 -9.88E-01 -9.97E-04 2.39E-04 -1.73E-05 6.23E-07 -7.84E-09 S15 2.91E+00 -3.76E-03 1.81E-04 -5.62E-06 9.14E-08 -7.88E-10 S16 1.45E+00 -4.15E-03 1.56E-04 -3.99E-06 5.03E-08 -3.59E-10

[0159] In this embodiment, the field curvature curve, F-θ distortion curve, transverse chromatic aberration curve, axial aberration curve, and MTF curve of the optical lens are respectively as follows: Figure 20 , Figure 21 , Figure 22 , Figure 23 , Figure 24 As shown.

[0160] from Figure 20As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.15mm to 0.05mm, indicating that the optical lens can effectively correct the field curvature.

[0161] from Figure 21 As can be seen, the F-θ distortion of the optical lens is controlled within ±15%, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the unfolded image.

[0162] from Figure 22 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can correct the chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane very well.

[0163] from Figure 23 As can be seen, the axial aberration offset is controlled within ±0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0164] from Figure 24 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0165] Please refer to Table 5 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, and maximum field of view FOV, as well as the values ​​corresponding to each conditional expression in each embodiment.

[0166] Table 5

[0167]

[0168]

[0169] In summary, the optical lens provided by this invention improves imaging quality, reduces aberrations, and enhances image quality through the rational configuration of lens surface shapes and the appropriate combination of optical power. This results in the lens possessing one or more advantages such as ultra-wide angle, high pixel count, and high image quality. The optical lens of this invention can achieve underwater imaging and exhibits excellent imaging performance.

[0170] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0171] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, eight pieces of lenses in total, characterized in that, In order from the object side to the imaging surface along the optical axis, the optical lens comprises in sequence: a first lens with negative refractive power, an image-side surface of which is a concave surface; a second lens with negative refractive power, an object-side surface of which is a convex surface and an image-side surface of which is a concave surface; a third lens with positive refractive power, an object-side surface of which is a convex surface and an image-side surface of which is a concave surface; a fourth lens with positive refractive power, an image-side surface of which is a convex surface; a fifth lens with positive refractive power, an image-side surface of which is a convex surface; a sixth lens with negative refractive power, both an object-side surface and an image-side surface of which are concave surfaces; a seventh lens with positive refractive power, an object-side surface of which is a concave surface and an image-side surface of which is a convex surface; an eighth lens with negative refractive power, an object-side surface of which is a convex surface and an image-side surface of which is a concave surface; wherein a radius of curvature R6 of the image-side surface of the third lens and a radius of curvature R13 of the object-side surface of the seventh lens satisfy: R6 / R13<-0.1; a maximum field of view FOV of the optical lens and an aperture value Fno of the optical lens satisfy: 50°<FOV / Fno<70°.

2. The optical lens of claim 1, wherein, a radius of curvature R6 of the image-side surface of the third lens and a radius of curvature R13 of the object-side surface of the seventh lens satisfy: -170<R6 / R13<-0.7; a maximum field of view FOV of the optical lens and an aperture value Fno of the optical lens satisfy: 56°<FOV / Fno<62°.

3. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a back focal length BFL of the optical lens satisfy: 1<BFL / f<1.

2.

4. The optical lens of claim 1, wherein, a maximum field of view FOV of the optical lens, an effective focal length f of the optical lens and a real image height IH corresponding to the maximum field of view of the optical lens satisfy: 35°<FOV×f / IH<55°.

5. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a radius of curvature R6 of the image-side surface of the third lens satisfy: 2<R6 / f≤1335.

52.

6. The optical lens of claim 1, wherein, an effective focal length f of the optical lens and a radius of curvature R13 of the object-side surface of the seventh lens satisfy: -11<R13 / f<-6.

7. The optical lens of claim 1, wherein, a focal length f3 of the third lens and a radius of curvature R5 of the object-side surface of the third lens satisfy: 0.1<R5 / f3<1.5; the focal length f3 of the third lens and a radius of curvature R6 of the image-side surface of the third lens satisfy: 0.5<R6 / f3<130.

8. The optical lens of claim 1, wherein, a focal length f7 of the seventh lens and a radius of curvature R13 of the object-side surface of the seventh lens satisfy: -5.5<R13 / f7<-3.3; the focal length f7 of the seventh lens and a radius of curvature R14 of the image-side surface of the seventh lens satisfy: -0.7<R14 / f7<-0.

2.

9. The optical lens of claim 1, wherein, a radius of curvature R5 of the object-side surface of the third lens and a radius of curvature R6 of the image-side surface of the third lens satisfy: -1<(R5-R6) / (R5+R6)<0.

10. The optical lens of claim 1, wherein, a radius of curvature R13 of the object-side surface of the seventh lens and a radius of curvature R14 of the image-side surface of the seventh lens satisfy: 0<(R13-R14) / (R13+R14)<1.

Images