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; and 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 convex image side surface; and 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. 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] This invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Technology

[0002] In the field of modern motion capture, high-performance portable optical systems are a core requirement. Currently, most action camera lenses on the market employ large-aperture, ultra-wide-angle designs to adapt to high-speed motion scenes and extreme environments. However, these traditional optical structures generally suffer from reduced image quality in low-light conditions and insufficient dynamic range. Simultaneously, the increased field of view makes aberration correction difficult, further degrading image quality; and existing lenses have relatively small imaging surfaces, making it difficult to meet market demands. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An optical lens has eight lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane: The first lens with negative optical power has a convex object side and a concave image side. A second lens with negative optical power has a convex object side and a concave image side. A third lens with negative optical power has a concave object side and a convex image side. The fourth lens with positive optical power has a convex object-side surface and a convex image-side surface. The fifth lens with positive optical power has a convex object-side surface and a convex image-side surface. The sixth lens with negative optical power has a concave object side and a convex image side. The seventh lens with negative optical power has an object-side surface that is convex near the optical axis and an image-side surface that is concave near the optical axis. The eighth lens, which has positive optical power, has a convex object-side surface and a convex image-side surface. Wherein, the true 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: 1.4 < (IH / 2) / (f×θ) < 1.6; the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: -140 <f56 / f<-70。

[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 effective focal length f of the optical lens satisfy: 7.5<TTL / f<9; 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: 1.9<TTL / IH<2.2.

[0006] Further preferably, the optical lens satisfies one or more of the following conditional expressions: the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 40°<FOV / Fno<60°; 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: 33°<f×FOV / IH<44°; the clear aperture semi-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)<0.32.

[0007] 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: 10<IH / EPD<14; 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: 3.5<IH / f<4.5.

[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: -23<f1 / f<-17; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.5<f2 / f<-2; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.7<f4 / f<2.2; 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 f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.3<f6 / f<-1; the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -4.1<f7 / f<-3.1.

[0009] It is further preferred that the optical lens satisfies one or more of the following conditional expressions: the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -8.7 < f3 / f < -7; the radius of curvature R5 of the object-side surface of the third lens and the effective focal length f of the optical lens satisfy: -1 < R5 / f < -0.8; the radius of curvature R6 of the image-side surface of the third lens and the effective focal length f of the optical lens satisfy: -1.4 < R6 / f < -1.

[0010] It is further preferred that the optical lens satisfies one or more of the following conditional expressions: the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.9 < f8 / f < 1.1; the radius of curvature R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 0.8 < R15 / f < 1; the radius of curvature R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -0.8 < R16 / f < -0.6.

[0011] It is further preferred 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 combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 2.3 < f1234 / f5678 < 3; the focal length f3 of the third lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: -2.8 < f3 / f1234 < -2.2; the focal length f8 of the eighth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.8 < f8 / f5678 < 1.

[0012] It is further preferred that the optical lens satisfies one or more of the following conditional expressions: the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.2 < f2 / f3 < 0.4; the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -4.4 < f3 / f4 < -3.5; the focal length f3 of the third lens and the focal length f8 of the eighth lens satisfy: -8.5 < f3 / f8 < -7; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4.1 < f7 / f8 < -3.1.

[0013] Further preferably, the optical lens satisfies one or more of the following conditions: the true 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: 1.44 < (IH / 2) / (f×θ) < 1.56; the combined focal length f56 of the fifth lens and the sixth lens satisfies: -127.69 <f56 / f<-80.16。

[0014] The optical lens provided by this 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. Attached Figure Description

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

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

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

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

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

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

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

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

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

[0024] Figure 10 This 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, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0047] In the optical lens according to the embodiment of the present invention, the number of lenses having optical power is eight, which are sequentially arranged along an optical axis from an object side to an imaging surface as follows: 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 embodiments, the first lens may have negative optical power, an object side surface thereof is convex, and an image side surface thereof is concave. The second lens may have negative optical power, an object side surface thereof is convex, and an image side surface thereof is concave. The third lens may have negative optical power, an object side surface thereof is concave, and an image side surface thereof is convex. The fourth lens may have positive optical power, an object side surface thereof is convex, and an image side surface thereof is convex. The fifth lens may have positive optical power, an object side surface thereof is convex, and an image side surface thereof is convex. The sixth lens may have negative optical power, an object side surface thereof is concave, and an image side surface thereof is convex. The seventh lens may have negative optical power, an object side surface thereof is convex at a position close to the optical axis, and an image side surface thereof is concave at a position close to the optical axis. The eighth lens may have positive optical power, an object side surface thereof is convex, and an image side surface thereof is convex.

[0049] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be arranged 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 adjust the brightness of imaging.

[0050] In some embodiments, the optical lens may further include a filter, which is arranged between the eighth lens and the imaging surface. The filter is used for filtering out interference light, so as to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0051] In some embodiments, the fifth lens and the sixth lens can be cemented to form a cemented lens group with negative optical power, which can effectively correct the chromatic aberration of the optical lens, reduce the decentration 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 reducing the difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens. In some embodiments, the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: -140<f56 / f<-70. More specifically, -127.69<f56 / f<-80.16.

[0052] In some embodiments, the true 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: 1.4<(IH / 2) / (f×θ)<1.6. Satisfying the above range allows the optical lens to have a proper distortion value and provide a high-definition imaging effect. More specifically, 1.44<(IH / 2) / (f×θ)<1.56.

[0053] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 7.5<TTL / f<9. Satisfying the above range can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens. More specifically, 8.09<TTL / f<8.39.

[0054] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.9<TTL / IH<2.2. Satisfying the above range ensures that when the lens has the same total length, it has a larger image surface, which can match a larger-size imaging chip to achieve high-definition imaging, and better achieve the balance between the small total length and the large image surface of the lens. More specifically, 2.04<TTL / IH<2.09.

[0055] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 40°<FOV / Fno<60°. Satisfying the above condition is conducive to expanding the field of view of the lens and increasing the aperture of the lens, realizing the characteristics of wide angle and large aperture of the lens. The wide-angle characteristic can meet the demand of large-range detection. More specifically, 45.44°<FOV / Fno<56.8°.

[0056] In some embodiments, the effective focal length f of the optical lens, the true 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: 33°<f×FOV / IH<44°. Satisfying the above conditional expression, by reasonably limiting the relationship among the focal length, field of view and image height of the optical lens, it is conducive to realizing the balance between the field of view of the optical lens and large-target-surface imaging, and better meets the usage requirement of high image quality shooting of the optical lens. More specifically, 36.84°<f×FOV / IH<39.4°.

[0057] In some embodiments, the clear half-aperture d1 of the object side surface of the first lens, the true 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)<0.32. Satisfying the above range can ensure the balance among the size, field of view and image surface of the optical lens.

[0058] 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: 10<IH / EPD<14. 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 vignetting is avoided. More specifically, 11.29<IH / EPD<12.64.

[0059] 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: 3.5<IH / f<4.5. Meeting the above range, the ultra-wide angle and large image surface characteristics are achieved by reasonably controlling the ratio of the image height to the focal length of the lens. More specifically, 3.94<IH / f<4.05.

[0060] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -23<f1 / f<-17. Meeting the above range, the first lens has an appropriate negative focal length, which is beneficial to expanding the field of view of the optical lens. More specifically, -20.72<f1 / f<-18.63.

[0061] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.5<f2 / f<-2. Meeting the above range, the second lens also adopts a negative lens, which can further diverge light and increase the field of view of the imaging system. More specifically, -2.24<f2 / f<-2.19.

[0062] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.7<f4 / f<2.2. Meeting the above range, the fourth lens has appropriate optical power to converge the incident light from the front end, which is beneficial to correcting the aberration caused by the front lens group and the distortion of the edge field of view, so that the lens has small distortion and can provide high-definition imaging effects. More specifically, 1.92<f4 / f<2.

[0063] 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, facilitating the correction of astigmatism and field curvature, improving the imaging quality of the optical lens, and ensuring the stability of the optical system. More specifically, 1.16<f5 / f<1.21.

[0064] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.3<f6 / f<-1. Meeting the above range enables sufficient correction of various aberrations of the optical lens, improves resolution, and achieves high resolution. More specifically, -1.16<f6 / f<-1.11.

[0065] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -4.1 < f7 / f < -3.1. Meeting the above range is beneficial to the smooth transition of light, corrects the field curvature and distortion of the optical lens, and improves the imaging quality of the optical lens. More specifically, -3.71 < f7 / f < -3.49.

[0066] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -8.7 < f3 / f < -7; the curvature radius R5 of the object-side surface of the third lens and the effective focal length f of the optical lens satisfy: -1 < R5 / f < -0.8; the curvature radius R6 of the image-side surface of the third lens and the effective focal length f of the optical lens satisfy: -1.4 < R6 / f < -1. Meeting the above range allows the third lens to have proper optical power and surface shape, which can control the traveling direction of the light path, provide a more reasonable incident angle of light for subsequent lenses, improve the relative illuminance uniformity, and enhance imaging quality. More specifically, -7.91 < f3 / f < -7.62; -0.93 < R5 / f < -0.88; -1.22 < R6 / f < -1.16.

[0067] 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 < 1.1; the curvature radius R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 0.8 < R15 / f < 1; the curvature radius R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -0.8 < R16 / f < -0.6. Meeting the above range is beneficial 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, 0.97 < f8 / f < 1.02; 0.85 < R15 / f < 0.89; -0.69 < R16 / f < -0.65.

[0068] In some embodiments, 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: 2.8 < f1234 / f < 3.4; 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: 1.1 < f5678 / f < 1.3; 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: 2.3 < f1234 / f5678 < 3. Satisfying 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 before the diaphragm and improve the overall imaging quality. More specifically, 3.03 < f1234 / f < 3.08; 1.11 < f5678 / f < 1.18; 2.59 < f1234 / f5678 < 2.73.

[0069] In some embodiments, the focal length f3 of the third lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: -2.8 < f3 / f1234 < -2.2. Satisfying the above range, reasonably setting the proportion of the focal length of the third lens in the lens group before the diaphragm is conducive to the smooth transition of light, reducing the correction difficulty of field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, -2.56 < f3 / f1234 < -2.49.

[0070] In some embodiments, the focal length f8 of the eighth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.8 < f8 / f5678 < 1. Satisfying the above range, reasonably setting the proportion of the focal length of the eighth lens in the lens group after the diaphragm helps to collect light reasonably, ensure the light flux, improve the relative illumination, so that the brightness of the optical lens at the image plane is improved. More specifically, 0.86 < f8 / f5678 < 0.89.

[0071] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0.2 < f2 / f3 < 0.4; the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -4.4 < f3 / f4 < -3.5; the focal length f3 of the third lens and the focal length f8 of the eighth lens satisfy: -8.5 < f3 / f8 < -7; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4.1 < f7 / f8 < -3.1. Satisfying the above ranges is conducive 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, 0.27 < f2 / f3 < 0.3; -3.98 < f3 / f4 < -3.91; -7.84 < f3 / f8 < -7.67; -3.74 < f7 / f8 < -3.44.

[0072] In some embodiments, the distance BL on the optical axis from the image side surface of the eighth lens to the imaging surface and the effective focal length f of the optical lens satisfy: 0.55 < BL / f < 0.59. Satisfying the above condition is conducive to realizing a short back focal length of the lens, and is conducive to realizing miniaturization of the lens while ensuring sufficient space for installation of optical elements.

[0073] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: -1.5 < R15 / R16 < -1.1; the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface of the eighth lens satisfy: 0.1 < (R15-R16) / (R15+R16) < 0.2. Satisfying the above range enables the eighth lens to have a proper surface shape, can balance various aberrations generated by the optical lens, and improves the imaging quality of the optical lens. More specifically, -1.32 < R15 / R16 < -1.27; 0.11 < (R15-R16) / (R15+R16) < 0.14.

[0074] 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: -8 < (R5+R6) / (R5-R6) < -7. Satisfying the above range, the third lens is a meniscus lens, which collects light with large field angles as much as possible and allows the light to enter the rear system smoothly, increases the luminous flux of the optical lens, and effectively expands the field of view range of the optical lens. More specifically, -7.41 < (R5+R6) / (R5-R6) < -7.37.

[0075] In some embodiments, the radius of curvature R15 of the object-side surface of the eighth lens, the central thickness CT8 of the eighth lens, and the radius of curvature R16 of the image-side surface of the eighth lens satisfy: 0.3<(R15-CT8) / R16<0.5. Satisfying the above range, reasonably setting the relationship between the surface shape and thickness of the eighth lens is beneficial to lens processing and improves yield. More specifically, 0.34<(R15-CT8) / R16<0.4.

[0076] In some embodiments, the optical lens satisfies the following conditional expressions: 3.6mm < f < 4.6mm; 1.2mm < EPD < 1.6mm; 33mm < TTL < 35mm; 2.6 < Fno < 3.4; 13° < CRA < 15°; 2.3mm < BL < 2.4mm; 140° < FOV < 170°; 16mm < IH < 17mm. In the above conditional expressions, f represents the effective focal length 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, CRA represents the chief ray angle of incidence at the maximum image height of the optical lens, BL represents the distance on the optical axis from the image-side surface of the eighth lens to the imaging surface, FOV represents the maximum field of view of the optical lens, and IH represents the actual image height corresponding to the maximum field of view of the optical lens. Satisfying the above ranges, the optical lens has at least one or more advantages such as miniaturization, large image surface, large field of view, etc. More specifically, 4.05mm < f < 4.21mm; 1.3mm < EPD < 1.46mm; 33.98mm < TTL < 34mm; 2.79 < Fno < 3.21; 13.54° < CRA < 13.83°; 2.33mm < BL < 2.35mm; 145.44° < FOV < 159.1°; 16.37mm < IH < 16.57mm.

[0077] In some embodiments, the lens material in the optical lens provided by the present invention may be glass or plastic. When the lens is made of plastic, the production cost can be effectively reduced. On the other hand, when the lens is made of glass, the low dispersion property of glass itself can effectively correct the geometric chromatic aberration of the optical system. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve imaging quality.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] Example 1

[0082] 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.

[0083] 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 convex. 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 convex. The object-side surface S16 and the image-side surface S17 of filter G1 are both planar. The imaging plane S18 is a plane.

[0084] The first, fourth, fifth, and sixth lenses are glass spherical lenses, while the second, third, seventh, and eighth lenses are glass aspherical lenses.

[0085] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0086] Table 1-1

[0087] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0088] Table 1-2

[0089] 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.

[0090] Figure 2 The 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 -0.04 mm to 0.08 mm, indicating that the optical lens can effectively correct the field curvature.

[0091] Figure 3The 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 0~80%, indicating that the optical lens can correct distortion well.

[0092] 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 0.02 mm, indicating that the optical lens can correct axial aberration well.

[0093] 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 -1 μm to 3 μm, indicating that the optical lens can effectively correct chromatic aberration.

[0094] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in 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 this example is above 0.4 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.

[0095] Example 2

[0096] Please see Figure 7 The 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 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.

[0097] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0098] Table 2-1

[0099] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0100] Table 2-2

[0101] 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.

[0102] from Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.08mm, indicating that the optical lens can effectively correct the field curvature.

[0103] from Figure 9 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.

[0104] from Figure 10 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0105] from Figure 11 As 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.

[0106] from Figure 12 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.

[0107] Example 3

[0108] 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 of this embodiment is roughly the same as that of 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.

[0109] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0110] Table 3-1

[0111] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0112] Table 3-2

[0113] 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.

[0114] from Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.08mm, indicating that the optical lens can effectively correct the field curvature.

[0115] 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.

[0116] from Figure 16 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0117] from Figure 17 As 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.

[0118] 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.

[0119] Example 4

[0120] 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.

[0121] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0122] Table 4-1

[0123] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0124] Table 4-2

[0125] 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.

[0126] from Figure 20 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.02mm to 0.09mm, indicating that the optical lens can effectively correct the field curvature.

[0127] from Figure 21 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.

[0128] from Figure 22 As can be seen, the axial aberration offset is controlled within -0.01mm to 0.02mm, indicating that the optical lens can effectively correct axial aberration.

[0129] from Figure 23 As 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.

[0130] from Figure 24 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In 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, which has good imaging quality and good detail resolution.

[0131] 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.

[0132] Table 5

[0133] 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.

[0134] 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.

[0135] 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, It sequentially comprises from the object side to the imaging surface along the optical axis: a first lens with negative refractive power, the object-side surface of which is convex, and the image-side surface of which is concave; a second lens with negative refractive power, the object-side surface of which is convex, and the image-side surface of which is concave; a third lens with negative refractive power, the object-side surface of which is concave, and the image-side surface of which is convex; a fourth lens with positive refractive power, the object-side surface of which is convex, and the image-side surface of which is convex; a fifth lens with positive refractive power, the object-side surface of which is convex, and the image-side surface of which is convex; a sixth lens with negative refractive power, the object-side surface of which is concave, and the image-side surface of which is convex; a seventh lens with negative refractive power, the object-side surface of which is convex near the optical axis, and the image-side surface of which is concave near the optical axis; an eighth lens with positive refractive power, the object-side surface of which is convex, and the image-side surface of which is convex; wherein, the actual 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: 1.4 < (IH / 2) / (f×θ) < 1.6; the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: -140 < f56 / f < -70.

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 effective focal length f of the optical lens satisfy: 7.5 < TTL / f < 9; the total optical length TTL of the optical lens and the actual image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.9 < TTL / IH < 2.

2.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 40° < FOV / Fno < 60°; the effective focal length f of the optical lens, the actual 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: 33° < f×FOV / IH < 44°; the clear semi-aperture d1 of the object-side surface of the first lens, the actual 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.

32.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies one or more of the following conditional expressions: the actual 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: 10 < IH / EPD < 14; the actual 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: 3.5 < IH / f < 4.

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: -23<f1 / f<-17; the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.5<f2 / f<-2; the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 1.7<f4 / f<2.2; 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 f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -1.3<f6 / f<-1; the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -4.1<f7 / f<-3.

1.

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 f3 of the third lens and the effective focal length f of the optical lens satisfy: -8.7<f3 / f<-7; the curvature radius R5 of the object-side surface of the third lens and the effective focal length f of the optical lens satisfy: -1<R5 / f<-0.8; the curvature radius R6 of the image-side surface of the third lens and the effective focal length f of the optical lens satisfy: -1.4<R6 / f<-1.

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 f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 0.9<f8 / f<1.1; the curvature radius R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 0.8<R15 / f<1; the curvature radius R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: -0.8<R16 / f<-0.

6.

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 combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 2.3<f1234 / f5678<3; the focal length f3 of the third lens and the combined focal length f1234 of the first lens, the second lens, the third lens and the fourth lens satisfy: -2.8<f3 / f1234<-2.2; the focal length f8 of the eighth lens and the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: 0.8<f8 / f5678<1.

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 f2 of the second lens and the focal length f3 of the third lens satisfy: 0.2 < f2 / f3 < 0.4; the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -4.4 < f3 / f4 < -3.5; the focal length f3 of the third lens and the focal length f8 of the eighth lens satisfy: -8.5 < f3 / f8 < -7; the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: -4.1 < f7 / f8 < -3.

1.

10. 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 angle 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 angle of the optical lens satisfy: 1.44 < (IH / 2) / (f×θ) < 1.56; the combined focal length f56 of the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: -127.69 < f56 / f < -80.16.

Images