Optical lens

Abstract

The application provides an optical lens, which has eight lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, a convex object side surface and a concave image side surface; a second lens with negative optical power, a convex object side surface and a concave image side surface; a third lens with negative optical power, a concave object side surface and a convex image side surface; a fourth lens with positive optical power, a convex object side surface and a convex image side surface; a fifth lens with positive optical power, a convex object side surface and a convex image side surface; a sixth lens with negative optical power, a concave object side surface and a concave image side surface; a seventh lens with negative optical power, a convex object side surface near the optical axis and a concave image side surface near the optical axis; and an eighth lens with positive optical power, a convex object side surface. The optical lens can improve the imaging quality of the optical lens, reduce aberration and improve the imaging quality of the optical lens.

Description

Technical Field

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

[0002] In the field of modern motion image capture, high-performance portable optical systems are a core demand. Most action camera lenses currently on the market adopt large-aperture and ultra-wide-angle designs to adapt to high-speed motion scenarios and extreme environment shooting. However, these conventional optical structures generally have the problems of degraded imaging quality in low-light environments and insufficient dynamic range. At the same time, the increase of the field of view of the lens leads to difficulty in aberration correction of the system and degradation of imaging quality; in addition, the imaging target surface of existing lenses is relatively small, which is difficult to meet market demands. Summary of the Invention

[0003] In view of the above problems, an objective of the present invention is to provide an optical lens, which has the advantage of excellent imaging quality.

[0004] To achieve the above objective, the technical solution adopted by the present invention is: An optical lens, in which the number of lenses with optical power is eight, sequentially arranged from the object side to the imaging surface along the optical axis comprises: a first lens with negative optical power, whose object-side surface is convex and image-side surface is concave; a second lens with negative optical power, whose object-side surface is convex and image-side surface is concave; a third lens with negative optical power, whose object-side surface is concave and image-side surface is convex; a fourth lens with positive optical power, whose object-side surface is convex and image-side surface is convex; a fifth lens with positive optical power, whose object-side surface is convex and image-side surface is convex; a sixth lens with negative optical power, whose object-side surface is concave and image-side surface is concave; a seventh lens with negative optical power, whose object-side surface is convex at the position near the optical axis, and whose image-side surface is concave at the position near the optical axis; an eighth lens with positive optical power, whose object-side surface is convex; Wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5<TTL / f<9; 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: 0.65<f1234 / f5678<3.

[0005] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.8<TTL / IH<2.3; the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 50°<FOV / Fno<60°.

[0006] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 8<IH / EPD<12; the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2.8<IH / f<4.3.

[0007] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 36°<f×FOV / IH<57°; the clear aperture half-diameter d1 of the object side of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 0.18<d1 / (IH / 2) / tan(FOV / 2)<0.23; the real image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field of view of the optical lens satisfy: 1.05<(IH / 2) / (f×θ)<1.5.

[0008] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -24<f1 / f<-15; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.4<f2 / f<-1.4; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -8.8<f3 / f<-4.4; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3<f4 / f<2.1; the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1<f5 / f<1.4; the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f8 / f<1.6.

[0009] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.2<f6 / f<-0.9; the curvature radius R11 of the object-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: -1<R11 / f<-0.7; the curvature radius R12 of the image-side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 3.3<R12 / f<42.

[0010] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -6<f7 / f<-3; the curvature radius R13 of the object-side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 2.6<R13 / f<6; the curvature radius R14 of the image-side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 1.4<R14 / f<2.

[0011] Further preferably, the optical lens satisfies one or several of the following conditional expressions: the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.4<f1234 / f<3.1; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f5678 / f<2.4; the focal length f6 of the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.2<f6 / f5678<-0.4; the focal length f7 of the seventh lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -3.5<f7 / f5678<-2.

[0012] Further preferably, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.3<f5 / f6<-0.9; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.1<f6 / f7<0.4; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4.4<f7 / f8<-2.9.

[0013] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6.09<TTL / f<8.29; 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: 0.73<f1234 / f5678<2.67.

[0014] The optical lens provided by the present invention adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, can improve the imaging quality of the optical lens, reduce aberrations, enhance the imaging quality of the optical lens, and endow the lens with one or more advantages such as miniaturization, large field of view, large image plane, high pixel, and high imaging quality. Brief Description of the Drawings

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0016] Figure 2 is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 3 is an F-Theta distortion curve diagram of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 4 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 5 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 6 is an MTF curve diagram of the optical lens in Embodiment 1 of the present invention.

[0021] Figure 7 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 8 is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 9 is an F-Theta distortion curve diagram of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 10This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 11 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0026] Figure 12 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0027] Figure 13 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 14 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0029] Figure 15 This is the F-Theta distortion curve of the optical lens in Embodiment 3 of the present invention.

[0030] Figure 16 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0031] Figure 17 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0032] Figure 18 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0033] Figure 19 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0034] Figure 20 This is a field curvature curve diagram of the optical lens in Embodiment 4 of the present invention.

[0035] Figure 21 This is the F-Theta distortion curve of the optical lens in Embodiment 4 of the present invention.

[0036] Figure 22 This is an axial aberration curve of the optical lens in Embodiment 4 of the present invention.

[0037] Figure 23 This is a chromatic aberration curve of the optical lens in Embodiment 4 of the present invention.

[0038] Figure 24 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0039] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0040] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0041] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0042] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0043] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0044] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0045] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0046] It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other under the condition of no conflict. The present application will be described in detail below with reference to the accompanying drawings in conjunction with the embodiments.

[0047] In the optical lens according to the embodiment of the present invention, the number of lenses with optical power is eight, which are sequentially arranged from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens.

[0048] In some implementations, the first lens may have negative optical power, with its object side surface being convex and its image side surface being concave. The second lens may have negative optical power, with its object side surface being convex and its image side surface being concave. The third lens may have negative optical power, with its object side surface being concave and its image side surface being convex. The fourth lens may have positive optical power, with its object side surface being convex and its image side surface being convex. The fifth lens may have positive optical power, with its object side surface being convex and its image side surface being convex. The sixth lens may have negative optical power, with its object side surface being concave and its image side surface being concave. The seventh lens may have negative optical power, with its object side surface being convex near the optical axis and its image side surface being concave near the optical axis. The eighth lens may have positive optical power, with its object side surface being convex, and its image side surface may be concave or convex.

[0049] In some implementations, the optical lens may further include a diaphragm, and the diaphragm may be located between the fourth lens and the fifth lens. It can be understood that the diaphragm is used to limit the amount of incident light so as to change the brightness of the formed image.

[0050] In some implementations, the optical lens may further include an optical filter, which is disposed between the eighth lens and the imaging surface. The optical filter is used to filter out interfering light, preventing the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0051] In some implementations, the fifth lens and the sixth lens can be cemented to form a cemented lens group with optical power, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby lowering the difficulty of the processing technology of the optical lens and increasing the assembly yield of the optical lens.

[0052] In some implementations, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5<TTL / f<9. Meeting the above range can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens. More specifically, 6.09<TTL / f<8.29.

[0053] 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: 0.65<f1234 / f5678<3; the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.4<f1234 / f<3.1; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f5678 / f<2.4. Meeting the above ranges, by reasonably setting the focal lengths of the lens groups before and after the diaphragm, it is beneficial to balance various aberrations generated by the lens group in front of the diaphragm, and improve the overall imaging quality. More specifically, 0.73<f1234 / f5678<2.67; 1.57<f1234 / f<2.84; 1.05<f5678 / f<2.14.

[0054] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.8<TTL / IH<2.3. Meeting the above range ensures that the lens has a large image plane under the condition of the same total length, can match an imaging chip of a larger size to achieve high-definition imaging, and better realize the balance between the small total length and the large image plane of the lens. More specifically, 2<TTL / IH<2.09.

[0055] In some embodiments, the maximum field of view FOV of the optical lens and the F-number Fno of the optical lens satisfy: 50°<FOV / Fno<60°. Meeting the above conditions is beneficial to expand the field of view of the lens and increase the aperture of the lens, so as to realize the characteristics of wide angle and large aperture of the lens. The wide-angle characteristic can meet the demand for large-range detection. More specifically, 54.73°<FOV / Fno<56.8°.

[0056] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 8<IH / EPD<12. Meeting the above range can increase the width of the light beam entering the optical lens, so that the brightness of the optical lens at the image plane is improved and the occurrence of vignetting is avoided. More specifically, 8.48<IH / EPD<11.38.

[0057] In some embodiments, the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2.8<IH / f<4.3. Meeting the above range, by reasonably controlling the ratio of the image height to the focal length of the lens, the characteristics of ultra-wide angle and large image plane are realized. More specifically, 3.02<IH / f<4.

[0058] In some embodiments, the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 36°<f×FOV / IH<57°. Meeting the above conditional expression and reasonably limiting the relationship among the focal length, field angle and image height of the optical lens is beneficial to achieving a balance between the field angle of the optical lens and large-target-surface imaging, and better meets the use requirements of the optical lens for high-image-quality shooting. More specifically, 39.58°<f×FOV / IH<52.43°.

[0059] In some embodiments, the clear aperture half-diameter d1 of the object side surface of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.18<d1 / (IH / 2) / tan(FOV / 2)<0.23. Meeting the above range can ensure the balance among the size, field angle and image plane of the optical lens.

[0060] In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field angle of the optical lens satisfy: 1.05<(IH / 2) / (f×θ)<1.5. Meeting the above range can enable the lens to have a small distortion value and provide a high-definition imaging effect. More specifically, 1.08<(IH / 2) / (f×θ)<1.43.

[0061] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -24<f1 / f<-15. Meeting the above range, the first lens has an appropriate negative focal length, which is beneficial to expanding the field angle of the optical lens. More specifically, -21.81<f1 / f<-17.15.

[0062] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.4<f2 / f<-1.4. Meeting the above range, the second lens also adopts a negative lens, which can further diverge light rays and improve the field angle of the imaging system. More specifically, -2.2<f2 / f<-1.6.

[0063] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -8.8<f3 / f<-4.4. Meeting the above range, the third lens has an appropriate focal power, which can control the optical path direction, provide a more reasonable light incident angle for subsequent lenses, improve the uniformity of relative illumination, and enhance the imaging quality. More specifically, -8.02<f3 / f<-4.87.

[0064] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3<f4 / f<2.1. Meeting the above range, the fourth lens has an appropriate optical power, converges the incident light from the front end, which is beneficial for correcting the aberration caused by the front lens group and the distortion of the marginal field of view, so that the lens has small distortion and can provide a high-definition imaging effect. More specifically, 1.45<f4 / f<1.89.

[0065] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1<f5 / f<1.4. Meeting the above range is conducive to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system. More specifically, 1.11<f5 / f<1.28.

[0066] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f8 / f<1.6. Meeting the above range is conducive to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system. More specifically, 1.03<f8 / f<1.44.

[0067] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.2<f6 / f<-0.9; the radius of curvature R11 of the object side of the sixth lens and the effective focal length f of the optical lens satisfy: -1<R11 / f<-0.7; the radius of curvature R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: 3.3<R12 / f<42. Meeting the above range allows various aberrations of the optical lens to be fully corrected, which can improve the resolution and achieve high resolution. More specifically, -1.12<f6 / f<-0.97; -0.9<R11 / f<-0.79; 3.7<R12 / f<38.3.

[0068] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -6<f7 / f<-3; the radius of curvature R13 of the object side of the seventh lens and the effective focal length f of the optical lens satisfy: 2.6<R13 / f<6; the radius of curvature R14 of the image side of the seventh lens and the effective focal length f of the optical lens satisfy: 1.4<R14 / f<2. Meeting the above range is conducive to the smooth transition of light, while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, -5.56<f7 / f<-3.36; 2.9<R13 / f<5.41; 1.58<R14 / f<1.81.

[0069] In some embodiments, the focal length f6 of the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.2<f6 / f5678<-0.4; the focal length f7 of the seventh lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -3.5<f7 / f5678<-2. Meeting the above ranges and reasonably setting the focal length proportion of the sixth lens and the seventh lens in the lens group behind the stop is beneficial to the smooth transition of light, reduces the difficulty of correcting the field curvature and distortion of the optical lens, and improves the imaging quality of the optical lens. More specifically, -1.06<f6 / f5678<-0.45; -3.18<f7 / f5678<-2.26.

[0070] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.3<f5 / f6<-0.9; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.1<f6 / f7<0.4; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4.4<f7 / f8<-2.9. Meeting the above ranges is beneficial to the smooth transition of light, facilitates the correction of aberrations of the optical lens, and improves the imaging quality of the optical lens. More specifically, -1.15<f5 / f6<-1.03; 0.17<f6 / f7<0.34; -3.94<f7 / f8<-3.24.

[0071] In some embodiments, the distance BL on the optical axis from the image side surface of the eighth lens to the imaging plane and the effective focal length f of the optical lens satisfy: 0.44<BL / f<0.58. Meeting the above conditions is beneficial to realizing the short back focal length of the lens, and facilitates the miniaturization of the lens while ensuring sufficient space for the installation of optical elements.

[0072] In some embodiments, the focal length f1 of the first lens and the focal length f6 of the sixth lens satisfy: 15<f1 / f6<22; the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: 2.8<f1 / f7<7. Meeting the above ranges can avoid excessive deflection of light and reduce the difficulty of aberration correction. More specifically, 17.24<f1 / f6<19.58; 3.08<f1 / f7<6.47.

[0073] In some embodiments, the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -0.3<R11 / R12<0; the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -1<(R11+R12) / (R11-R12)<-0.5. Satisfying the above ranges can enable the sixth lens to have a suitable surface profile, which can balance various aberrations generated by the optical lens and improve the imaging quality of the optical lens. More specifically, -0.25<R11 / R12<-0.01; -0.97<(R11+R12) / (R11-R12)<-0.6.

[0074] In some embodiments, the curvature radius R13 of the object side of the seventh lens and the curvature radius R14 of the image side of the seventh lens satisfy: 1.5<R13 / R14<3.3; the curvature radius R13 of the object side of the seventh lens and the curvature radius R14 of the image side of the seventh lens satisfy: 1.8<(R13+R14) / (R13-R14)<4.4. Satisfying the above ranges can enable the seventh lens to have a suitable surface profile, which facilitates the smooth transition of light rays, and simultaneously corrects the field curvature and distortion of the optical lens, so as to improve the imaging quality of the optical lens. More specifically, 1.67<R13 / R14<3; 1.99<(R13+R14) / (R13-R14)<3.95.

[0075] In some embodiments, the optical lens satisfies the following conditional expressions: 3.7mm<f<6mm; 1.3mm<EPD<2.1mm; 30mm<TTL<36mm; 2.6<Fno<3; 13°<CRA<19°; 2.1mm<BL<2.6mm; 150°<FOV<170°; 16mm<IH<17mm. In the above conditional expressions, f denotes the effective focal length of the optical lens, EPD denotes the entrance pupil diameter of the optical lens, TTL denotes the total optical length of the optical lens, Fno denotes the aperture value of the optical lens, CRA denotes the chief ray incident angle at the maximum image height of the optical lens, BL denotes the distance on the optical axis from the image side of the eighth lens to the imaging surface, FOV denotes the maximum field angle of the optical lens, and IH denotes the real image height corresponding to the maximum field angle of the optical lens. Satisfying the above ranges, the optical lens has at least one or more advantages such as miniaturization, large image plane, and large field angle. More specifically, 4.09mm<f<5.41mm; 1.43mm<EPD<1.94mm; 32.94mm<TTL<34mm; 2.79<Fno<2.86; 13.88°<CRA<17.97°; 2.33mm<BL<2.43mm; 155°<FOV<160°; 16.37mm<IH<16.39mm.

[0076] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens is made of plastic, production costs can be effectively reduced. Conversely, when the lens is made of glass, the low dispersion characteristic of glass itself can effectively correct the geometric chromatic aberration of the optical system. The optical lens provided by the present invention can employ an all-glass lens structure, which can reduce dispersion, effectively correct chromatic aberration of the optical lens, and improve image quality.

[0077] In some embodiments, the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses can be spherical or aspherical lenses. Compared to spherical structures, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, the second, third, seventh, and eighth lenses of this invention are aspherical lenses; the first, fourth, fifth, and sixth lenses are spherical lenses.

[0078] In various embodiments of the present invention, when an aspherical lens is used, the shapes of each aspherical surface of the optical lens satisfy the following equations: ; Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and A, B, C, D, E, and F are the second, fourth, sixth, eighth, tenth, and twelfth order surface coefficients, respectively.

[0079] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0080] Example 1

[0081] Please see Figure 1 The diagram shown is a structural schematic of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0082] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave. The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave. The third lens L3 has negative optical power, its object side S5 is concave, and its image side S6 is convex. The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex. The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side is convex. The sixth lens L6 has negative optical power, its object side is concave, and its image side S11 is concave. The fifth lens L5 and the sixth lens L6 form a cemented lens group with negative optical power, that is, the cemented surface of the image side of the fifth lens L5 and the object side of the sixth lens L6 is S10. The seventh lens L7 has negative optical power. Its object-side surface S12 is convex near the optical axis, and its image-side surface S13 is concave near the optical axis. The eighth lens L8 has positive optical power, its object side S14 is convex, and its image side S15 is concave near the optical axis. The object-side surface S16 and the image-side surface S17 of filter G1 are both planar. The imaging plane S18 is a plane.

[0083] The first, fourth, fifth, and sixth lenses are glass spherical lenses, while the second, third, seventh, and eighth lenses are glass aspherical lenses.

[0084] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0085] Table 1-1

[0086] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0087] Table 1-2

[0088] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown.

[0089] Figure 2The field curvature curve of Example 1 is shown, which represents the degree of curvature of light in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.02 mm to 0.06 mm, indicating that the optical lens can effectively correct the field curvature.

[0090] Figure 3 The F-Theta distortion curve of Example 1 is shown, which represents the F-Theta distortion of light at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~30%, indicating that the optical lens can correct distortion well.

[0091] Figure 4 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within -0.01 mm to 0.03 mm, indicating that the optical lens can correct axial aberration well.

[0092] Figure 5 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0~4 μm, indicating that the optical lens can effectively correct chromatic aberration.

[0093] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields 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 this example is above 0.45 throughout the entire field of view. Within the range of 0–120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good image quality and good detail resolution.

[0094] Example 2

[0095] Please see Figure 7The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The optical lens in this embodiment is generally the same as that in Embodiment 1. The main difference is that the fifth lens L5 and the sixth lens L6 form a cemented lens group with positive optical power; the image side S15 of the eighth lens L8 is a convex surface; and the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0096] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0097] Table 2-1

[0098] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0099] Table 2-2

[0100] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.

[0101] from Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.05mm, indicating that the optical lens can effectively correct the field curvature.

[0102] from Figure 9 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~35%, indicating that the optical lens can correct distortion well.

[0103] from Figure 10 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.03mm, indicating that the optical lens can effectively correct axial aberration.

[0104] from Figure 11 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0~3μm, indicating that the optical lens can correct chromatic aberration well.

[0105] from Figure 12As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. Within the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality and good detail resolution.

[0106] Example 3

[0107] Please see Figure 13 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The optical lens in this embodiment is roughly the same as that in Embodiment 1. The main difference is that the image side surface S15 of the eighth lens L8 is a convex surface; the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0108] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0109] Table 3-1

[0110] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0111] Table 3-2

[0112] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 300 are respectively as follows: Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 As shown.

[0113] from Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.05mm to 0.08mm, indicating that the optical lens can effectively correct the field curvature.

[0114] from Figure 15 As can be seen, the F-Theta distortion of the optical lens is controlled within 0-85%, indicating that the optical lens can correct distortion well.

[0115] from Figure 16 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.03mm, indicating that the optical lens can effectively correct axial aberration.

[0116] from Figure 17As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 3μm, indicating that the optical lens can correct chromatic aberration well.

[0117] from Figure 18 As can be seen, the MTF value of this embodiment is above 0.35 throughout the entire field of view. Within the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality and good detail resolution.

[0118] Example 4

[0119] Please see Figure 19 The figure shows a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The optical lens in this embodiment is roughly the same as that in Embodiment 1. The main difference is that the optical parameters such as the radius of curvature, aspherical coefficient, and thickness of each lens surface are different.

[0120] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0121] Table 4-1

[0122] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0123] Table 4-2

[0124] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 400 are respectively as follows: Figure 20 , Figure 21 , Figure 22 , Figure 23 , Figure 24 As shown.

[0125] from Figure 20 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.06mm, indicating that the optical lens can effectively correct the field curvature.

[0126] from Figure 21 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~30%, indicating that the optical lens can correct distortion well.

[0127] from Figure 22 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.03mm, indicating that the optical lens can effectively correct axial aberration.

[0128] from Figure 23 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0~3μm, indicating that the optical lens can correct chromatic aberration well.

[0129] from Figure 24 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. Within the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating good imaging quality and good detail resolution.

[0130] 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, maximum field of view FOV, distance BL from the image side of the eighth lens to the imaging plane on the optical axis, and the numerical value corresponding to each conditional expression in each embodiment.

[0131] Table 5

[0132] In summary, the optical lens provided by the present invention uses eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as miniaturization, large field of view, large image plane, high pixel count, and high imaging quality.

[0133] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this 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 may be combined in any suitable manner in one or more embodiments or examples.

[0134] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising eight lenses having optical power, characterized in that, Along the optical axis from the object side to the imaging plane, the optical system sequentially comprises: a first lens with negative refractive power, wherein the object side surface thereof is a convex surface, and the image side surface thereof is a concave surface; a second lens with negative refractive power, wherein the object side surface thereof is a convex surface, and the image side surface thereof is a concave surface; a third lens with negative refractive power, wherein the object side surface thereof is a concave surface, and the image side surface thereof is a convex surface; a fourth lens with positive refractive power, wherein the object side surface thereof is a convex surface, and the image side surface thereof is a convex surface; a fifth lens with positive refractive power, wherein the object side surface thereof is a convex surface, and the image side surface thereof is a convex surface; a sixth lens with negative refractive power, wherein the object side surface thereof is a concave surface, and the image side surface thereof is a concave surface; a seventh lens with negative refractive power, wherein the object side surface thereof is a convex surface at the paraxial region, and the image side surface thereof is a concave surface at the paraxial region; an eighth lens with positive refractive power, wherein the object side surface thereof is a convex surface; wherein the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5<TTL / f<9; 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: 0.65<f1234 / f5678<3.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.8<TTL / IH<2.3; the maximum field of view FOV of the optical lens and the F-number Fno of the optical lens satisfy: 50°<FOV / Fno<60°.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 8<IH / EPD<12; the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2.8<IH / f<4.

3.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the effective focal length f of the optical lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 36°<f×FOV / IH<57°; the clear aperture half-diameter d1 of the object side surface of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.18<d1 / (IH / 2) / tan(FOV / 2)<0.23; the real image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens and the radian value θ of the maximum half field of view of the optical lens satisfy: 1.05<(IH / 2) / (f×θ)<1.

5.

5. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -24<f1 / f<-15; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.4<f2 / f<-1.4; the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -8.8<f3 / f<-4.4; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.3<f4 / f<2.1; the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1<f5 / f<1.4; the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f8 / f<1.

6.

6. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.2<f6 / f<-0.9; the radius of curvature R11 of the object side of the sixth lens and the effective focal length f of the optical lens satisfy: -1<R11 / f<-0.7; the radius of curvature R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: 3.3<R12 / f<42.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -6<f7 / f<-3; the radius of curvature R13 of the object side of the seventh lens and the effective focal length f of the optical lens satisfy: 2.6<R13 / f<6; the radius of curvature R14 of the image side of the seventh lens and the effective focal length f of the optical lens satisfy: 1.4<R14 / f<2.

8. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens and the effective focal length f of the optical lens satisfy: 1.4<f1234 / f<3.1; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f5678 / f<2.4; the focal length f6 of the sixth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -1.2<f6 / f5678<-0.4; the focal length f7 of the seventh lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -3.5<f7 / f5678<-2.

9. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.3<f5 / f6<-0.9; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.1<f6 / f7<0.4; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4.4<f7 / f8<-2.

9.

10. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6.09<TTL / f<8.29; 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: 0.73<f1234 / f5678<2.67.

Images