Optical system

Abstract

The application discloses an optical system, characterized in that the optical system comprises a first lens with negative optical power; a second lens with positive optical power; a third lens with positive optical power; a fourth lens with negative optical power; a fifth lens with positive optical power; a sixth lens with negative optical power; a seventh lens with positive optical power; and an eighth lens with negative optical power; the number of lenses with optical power in the optical system is eight; and the optical system satisfies the following conditional expression: -4.897<=F8 / F<=-1.391; wherein F is the total effective focal length of the optical system, and F8 is the effective focal length value of the eighth lens.

Description

Technical Field

[0001] This application relates to the field of optical technology, and more particularly to an optical system, an imaging device using the optical system, a gimbal, and a mobile platform. Background Technology

[0002] With the development of photography technology, shooting devices (such as aerial cameras, action cameras, or handheld cameras) are becoming increasingly thinner and smaller. This necessitates that the optical systems used in these devices also become thinner and smaller, and that they incorporate wide-angle lenses. Existing handheld gimbal camera lenses, to meet portability requirements, mostly employ compact wide-angle optical structures. However, wide-angle lenses introduce stray light in strong light environments, affecting the image sharpness of the optical system. Furthermore, due to gimbal load limitations, the lens weight cannot be too large; too many lens elements would increase the weight of the lens group and the overall optical length. Simultaneously, handheld shooting scenarios involve complex lighting conditions, alternating between low indoor light and strong outdoor light. Existing lenses often suffer from insufficient relative illumination at the edges, poor stray light suppression, and are prone to ghosting, flare, and inconsistent resolution across the entire field of view. Additionally, changes in ambient temperature can cause thermal drift in the lens elements, resulting in thermal defocusing, which is further amplified by the continuous movement of the gimbal.

[0003] Based on this, this application provides an optical system, an imaging device, a gimbal, and a movable platform. The optical system is lightweight, miniaturized, has low distortion, good heat-free operation, and a large field of view. At the same time, it can reduce the influence of stray light caused by incident light in strong light environments, thereby improving the imaging clarity of the optical system. Summary of the Invention

[0004] This application provides an optical system comprising, along the optical axis from the object side to the image side, the following elements in sequence: a first lens with negative optical power; a second lens with positive optical power; a third lens with positive optical power; a fourth lens with negative optical power; a fifth lens with positive optical power; a sixth lens with negative optical power; a seventh lens with positive optical power; and an eighth lens with negative optical power. The optical system comprises eight lenses with optical power. The optical system satisfies the following condition: -4.897 ≤ F8 / F ≤ -1.391, where F is the total effective focal length of the optical system and F8 is the effective focal length of the eighth lens.

[0005] According to exemplary embodiments of this application, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex, and the image-side surface is concave, convex, or flat; the object-side surface of the third lens is convex, and the image-side surface is concave, convex, or flat; the object-side surface of the fourth lens is convex, concave, or flat, and the image-side surface is concave; the object-side surface of the fifth lens is convex, and the image-side surface is convex, concave, or flat; the object-side surface of the sixth lens is convex, and the image-side surface is concave; the object-side surface of the seventh lens is convex, and the image-side surface is either convex or concave; the object-side surface of the eighth lens is convex, and the image-side surface is concave.

[0006] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: -2.034≤F1 / F≤-1.402; 0.960≤F2 / F≤1.636; 2.027≤F3 / F≤5.831; -2.859≤F4 / F≤-1.795; 1.477≤F5 / F≤2.171; -7.389≤F6 / F≤-3.290; 1.576≤F7 / F≤2.408; wherein F1 is the effective focal length of the first lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, F4 is the effective focal length of the fourth lens, F5 is the effective focal length of the fifth lens, F6 is the effective focal length of the sixth lens, and F7 is the effective focal length of the seventh lens.

[0007] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: 1.659≤F1_2 / F≤4.660; 1.404≤F3_8 / F≤4.131; 0.193≤F2 / F3≤0.726; -0.351≤F5 / F6_8≤-0.022; -1.297≤F7 / F8≤-0.443; wherein, F1_2 is the combined effective focal length of the first and second lenses, F3_8 is the combined effective focal length of the third to eighth lenses, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, F5 is the effective focal length of the fifth lens, F6_8 is the combined effective focal length of the sixth to eighth lenses, and F7 is the effective focal length of the seventh lens.

[0008] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: -13.509≤F8 / BFL≤-4.322; 0.006≤T23 / F3≤0.062; 2.876≤IH / D3≤4.534; 0.122≤R82 / IH≤0.219; where BFL is the back focal length of the optical system, T23 is the center distance from the image side of the second lens to the object side of the third lens, F3 is the effective focal length of the third lens, IH is the total image height of the optical system, D3 is the effective aperture of the object side of the third lens, and R82 is the radius of curvature of the image side of the eighth lens.

[0009] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: 0.488≤R12 / R21≤0.960; -3.158≤R72 / R81≤8.273; where R12 is the radius of curvature of the image-side surface of the first lens, R21 is the radius of curvature of the object-side surface of the second lens, R72 is the radius of curvature of the image-side surface of the seventh lens, and R81 is the radius of curvature of the object-side surface of the eighth lens.

[0010] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: 0.202≤T12 / TTL≤0.267; 0.509≤TTb / TTL≤0.628; 2.164≤TTL / F≤2.814; 0.271≤BFL / F≤0.399; 0.551≤D1 / TTL≤0.730; where T12 is the center distance from the image side of the first lens to the object side of the second lens, TTb is the center distance from the image side of the third lens to the image plane of the optical system, TTL is the total optical length of the optical system, BFL is the back focal length of the optical system, and D1 is the effective aperture of the object side of the first lens.

[0011] According to an exemplary embodiment of this application, the optical system satisfies the following condition: 5.995 mm -1 ≤(Vd3+Vd4+Vd5) / F3_5≤14.313 mm -1 Where Vd3 is the Abbe number of the third lens, Vd4 is the Abbe number of the fourth lens, Vd5 is the Abbe number of the fifth lens, and F3_5 is the combined effective focal length of the third to fifth lenses.

[0012] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: -1.849≤F1 / F≤-1.558; 1.067≤F2 / F≤1.487; 2.252≤F3 / F≤5.301; -2.599≤F4 / F≤-1.994; 1.641≤F5 / F≤1.974; -6.717≤F6 / F≤-3.656; 1.751≤F7 / F≤2.189; -4.452≤F8 / F≤-1.546; 1.843≤F1_2 / F≤4.236; 1.560≤F3_8 / F≤3.755; 0.214≤F2 / F3≤0.660;-0.319≤F5 / F6_8≤-0.024;-1.179≤F7 / F8≤-0.492;Where F1 is the effective focal length of the first lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, F4 is the effective focal length of the fourth lens, F5 is the effective focal length of the fifth lens, F6 is the effective focal length of the sixth lens, F7 is the effective focal length of the seventh lens, F1_2 is the combined effective focal length of the first and second lenses, F3_8 is the combined effective focal length of the third to eighth lenses, and F6_8 is the combined effective focal length of the sixth to eighth lenses.

[0013] According to an exemplary embodiment of this application, the optical system satisfies at least one of the following conditions: -12.281≤F8 / BFL≤-4.802; 0.007≤T23 / F3≤0.056; 0.542≤R12 / R21≤0.873; 0.224≤T12 / TTL≤0.243; 0.566≤TTb / TTL≤0.571; 2.404≤TTL / F≤2.558; 0.301≤BFL / F≤0.363; 0.612≤D1 / TTL≤0.664; 3.195≤IH / D3≤4.122; 0.135≤R82 / IH≤0.199; -2.871≤R72 / R81≤7.521; 6.661 mm -1 ≤(Vd3+Vd4+Vd5) / F3_5≤13.012 mm -1Wherein, BFL is the back focal length of the optical system, T23 is the center distance from the image side of the second lens to the object side of the third lens, F3 is the effective focal length of the third lens, R12 is the radius of curvature of the image side of the first lens, R21 is the radius of curvature of the object side of the second lens, T12 is the center distance from the image side of the first lens to the object side of the second lens, TTL is the total optical length of the optical system, TTb is the center distance from the image side of the third lens to the image plane of the optical system, D1 is the effective aperture of the object side of the first lens, IH is the total image height of the optical system, D3 is the effective aperture of the object side of the third lens, R72 is the radius of curvature of the image side of the seventh lens, R81 is the radius of curvature of the object side of the eighth lens, R82 is the radius of curvature of the image side of the eighth lens, Vd3 is the Abbe number of the third lens, Vd4 is the Abbe number of the fourth lens, Vd5 is the Abbe number of the fifth lens, and F3_5 is the combined effective focal length of the third to fifth lenses.

[0014] The optical system of this application achieves the following characteristics simultaneously by reasonably setting the number of lenses (e.g., eight), reasonably allocating the optical power of each lens, optimizing the surface shape of each lens, and reasonably setting the range of parameters: wide-angle (maximum field of view FOV=102°), miniaturization (TTL≤15.1mm), small size, lightweight, large aperture (FNO≤2.1), low distortion, high resolution, and no pyrolysis. Attached Figure Description

[0015] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0016] Figure 1 This is a schematic diagram of the optical system according to Embodiment 1 of this application;

[0017] Figure 2 This is a schematic diagram of the optical system according to Embodiment 2 of this application;

[0018] Figure 3 This is a schematic diagram of the optical system according to Embodiment 3 of this application;

[0019] Figure 4 This is a schematic diagram of the optical system according to Embodiment 4 of this application;

[0020] Figure 5 This is a schematic diagram of the optical system according to Embodiment 5 of this application. Detailed Implementation

[0021] 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 exemplary 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.

[0022] 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 this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0023] 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.

[0024] 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.

[0025] It should also be understood that the terms "comprising," "having," "including," etc., 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 a statement such as "at least one of..." appears after a list of listed features, it modifies the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to indicate "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0026] 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.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] An optical system according to an exemplary embodiment of this application may include eight lenses with optical power sequentially from the object side to the image side along the optical axis, namely 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.

[0029] In an exemplary embodiment, the first lens of the optical system has a negative optical power, with its object-side surface being convex and its image-side surface being concave. This configuration allows the first lens, designed in a meniscus shape, to collect as much light as possible from a large field of view into the rear optical system, increasing light transmission. The negative optical power also facilitates light divergence, ensuring a smooth transition of light paths. Furthermore, it allows large-angle light to enter the optical system as much as possible, improving illumination and reducing the optical path length of rear light rays, thus shortening the overall optical length and increasing light transmission.

[0030] In an exemplary embodiment, the second lens of the optical system has positive optical power, with its object-side surface being convex and its image-side surface being either concave or convex. This configuration allows the second lens to have positive optical power, converging the light rays diverging from the first lens, which helps reduce the rear aperture, while also appropriately controlling the light path, correcting aberrations, improving performance, and achieving high resolution. The convex object-side surface is used to converge the light rays emitted from the first lens, correcting aberrations, and avoiding an excessively large front aperture caused by excessive light divergence; the convex image-side surface, combined with the object-side surface, further converges the light rays, allowing for reasonable convergence of edge field-of-view rays, which helps reduce coma; the concave image-side surface can appropriately further diverge the light rays, facilitating a smooth transition of light to subsequent lenses, which is beneficial for performance improvement and reduced sensitivity.

[0031] In an exemplary embodiment, since the image-side curvature radius of the second lens is large, the convex, flat and concave surfaces are easy to change or fine-tune with each other, which usually has little impact on the overall technical effect of the optical system. Those skilled in the art can use the larger curvature radius of this surface as the optimization boundary condition, which obviously does not require creative effort.

[0032] In an exemplary embodiment, the third lens of the optical system has positive optical power, with both its object-side and image-side surfaces being convex. This configuration, with its positive optical power, further converges light rays, altering their trajectory and bringing them closer to the optical axis. This allows the light to smoothly enter the rear lens, reducing the rear aperture and improving the optical system's resolution. The convex object-side surface gathers the front-group light rays, reducing field curvature and lowering the light beam height, which helps reduce costs and achieve miniaturization of the optical system. The convex image-side surface corrects coma and other aberrations generated by the first and second lenses, and, in conjunction with the first and second lenses, achieves high resolution.

[0033] In an exemplary embodiment, the third lens of the optical system has positive optical power, with a convex object-side surface and a concave image-side surface. This configuration, with its positive optical power, further converges light rays, altering their trajectory and bringing them closer to the optical axis. This allows the light to smoothly enter the rear lens, reducing the rear aperture and improving the optical system's resolution. The convex object-side surface converges light from the front lens, reducing spherical aberration, lowering edge ray height, and shortening the overall length. The concave image-side surface effectively disperses the light rays converged from the object-side surface, preventing excessive convergence and increasing light transmission for higher resolution.

[0034] In an exemplary embodiment, since the image-side curvature radius of the third lens is large, the convex, flat and concave surfaces are easy to change or fine-tune with each other, which usually has little impact on the overall technical effect of the optical system. Those skilled in the art can use the larger curvature radius of this surface as the optimization boundary condition, which obviously does not require creative effort.

[0035] In an exemplary embodiment, the fourth lens of the optical system has negative optical power, with both its object-side and image-side surfaces being concave. This configuration, with its negative optical power, facilitates proper divergence of light rays, widens the gaps between peripheral light rays, reduces distortion, and improves resolution. The biconcave design also helps correct aberrations, allowing the central and peripheral field rays to return to their ideal positions, thereby improving resolution.

[0036] In an exemplary embodiment, the fourth lens of the optical system has negative optical power, with a convex object-side surface and a concave image-side surface. This configuration allows the fourth lens to have negative optical power, enabling proper divergence of light entering the lens. This adjusts the optical path difference between different fields of view and better converges light onto the image plane, correcting spherical aberration and improving image quality. The convex object-side surface converges light, preventing excessive refraction and reducing sensitivity; the concave image-side surface, combined with the negative optical power characteristic of the fourth lens, properly diverges light from each field of view, thereby correcting field curvature.

[0037] In the exemplary embodiment, since the object side curvature radius of the fourth lens is large, the convex, flat and concave surfaces are easy to change or fine-tune with each other, which usually has little impact on the overall technical effect of the optical system. Those skilled in the art can use the large curvature radius of this surface as the optimization boundary condition, which obviously does not require creative effort.

[0038] In an exemplary embodiment, the fifth lens of the optical system has positive optical power, with both its object-side and image-side surfaces being convex. This configuration can further reduce aberrations and improve image quality, while also adjusting the divergence angle of light rays, converging the light rays, making the light path smoother, and reducing the sensitivity of the system.

[0039] In an exemplary embodiment, since the image-side curvature radius of the fifth lens is large, the convex, flat and concave surfaces are easy to change or fine-tune with each other, which usually has little impact on the overall technical effect of the optical system. Those skilled in the art can use the large curvature radius of this surface as the optimization boundary condition, which obviously does not require creative effort.

[0040] In an exemplary embodiment, the sixth lens of the optical system has negative optical power, with a convex object-side surface and a concave image-side surface. This configuration allows the convex surface to collect light from the fifth lens, which helps to reduce the lens size; the concave surface transitions light to fit the image plane, sharing the system's optical power, allowing the seventh lens to more flexibly control the light and optimize the overall optical power configuration.

[0041] In an exemplary embodiment, the seventh lens of the optical system has positive optical power, with both its object-side and image-side surfaces being convex. This configuration allows the seventh lens to have positive optical power, converging light to the eighth lens and reducing system sensitivity. Its convex object-side surface allows for light adjustment; the convex image-side surface effectively converges light to meet the incident light requirements of the eighth lens, reducing lens sensitivity. It also allows light to bend and converge more quickly to reach the imaging plane, reducing the overall length of the lens.

[0042] In an exemplary embodiment, the seventh lens of the optical system has positive optical power, with a convex object-side surface and a concave image-side surface. This configuration allows the seventh lens to have positive optical power, further converging and adjusting the light rays in front, bringing them closer to the imaging plane, achieving miniaturization, and better converging the light rays onto the image plane, correcting spherical aberration, and improving image quality. The convex object-side surface helps correct optical system aberrations and balances resolution; the concave image-side surface further diverges the light rays, improving edge illumination and enhancing CRA (Critical Aspect Ratio).

[0043] In an exemplary embodiment, the eighth lens of the optical system has negative optical power, with a convex object-side surface and a concave image-side surface. This configuration facilitates the smooth entry of light into the image plane, improving resolution; it also helps to fully correct residual aberrations of the optical system, enabling the optical system to improve resolution and reduce optical performance such as distortion and CRA while maintaining a compact structure.

[0044] In an exemplary embodiment, the optical system satisfies: -2.034 ≤ F1 / F ≤ -1.402, where F1 is the effective focal length of the first lens and F is the total effective focal length of the optical system. This setting controls the negative focal length of the first lens within a suitable range, ensuring sufficient reception of light across a large field of view while avoiding excessive correction burden on the subsequent lenses. This balances a large field of view with improved aberration correction. For example, the optical system may further satisfy -1.849 ≤ F1 / F ≤ -1.558.

[0045] In an exemplary embodiment, the optical system satisfies: 0.960 ≤ F2 / F ≤ 1.636, where F2 is the effective focal length of the second lens and F is the total effective focal length of the optical system. This setting allows for a smooth transition and convergence of diverging light rays, which helps reduce light sensitivity; it also helps balance the system's high and low temperatures, ensuring stable optical performance of the lens under varying conditions. For example, the optical system may further satisfy 1.067 ≤ F2 / F ≤ 1.487.

[0046] In an exemplary embodiment, the optical system satisfies: 2.027 ≤ F3 / F ≤ 5.831, where F3 is the effective focal length of the third lens and F is the total effective focal length of the optical system. This setting allows for a smooth transition of light, improving the resolving power of the optical system. Furthermore, by limiting the relationship between the focal length of the third lens and the total effective focal length of the optical system, the optical path required for light rays exiting the third lens to converge to the aperture stop is shortened, thereby reducing the total optical length of the optical system and achieving miniaturization and high resolution. For example, the optical system may further satisfy 2.252 ≤ F3 / F ≤ 5.301.

[0047] In an exemplary embodiment, the optical system satisfies: -2.859 ≤ F4 / F ≤ -1.795, where F4 is the effective focal length of the fourth lens, and F is the total effective focal length of the optical system. This setting ensures a smooth transition of converging light from the large-aperture front end, helps balance various aberrations, and reduces lens sensitivity to some extent. Alternatively, the optical system may further satisfy -2.599 ≤ F4 / F ≤ -1.994.

[0048] In an exemplary embodiment, the optical system satisfies: 1.477 ≤ F5 / F ≤ 2.171, where F5 is the effective focal length of the fifth lens and F is the total effective focal length of the optical system. This configuration further controls the trajectory of light rays transmitted from the front optical system, allowing the light rays to smoothly converge into the rear optical system, resulting in a smoother light path and facilitating high resolution. For example, the optical system may further satisfy 1.641 ≤ F5 / F ≤ 1.974.

[0049] In an exemplary embodiment, the optical system satisfies: -7.389 ≤ F6 / F ≤ -3.290, where F6 is the effective focal length of the sixth lens and F is the total effective focal length of the optical system. This configuration effectively diverges the light rays transmitted from the front optical system to the rear optical system, thereby correcting astigmatism and field curvature, improving the resolving power of the optical system, and also helping to enlarge the imaging plane by diffusing the light rays from the sixth lens. Exemplarily, the optical system may further satisfy -6.717 ≤ F6 / F ≤ -3.656.

[0050] In an exemplary embodiment, the optical system satisfies: 1.576 ≤ F7 / F ≤ 2.408, where F7 is the effective focal length of the seventh lens and F is the total effective focal length of the optical system. This configuration facilitates better constraint of the rear-end light rays, thereby correcting chromatic aberration. Simultaneously, as a lens at the rear of the optical system, it reduces eccentricity sensitivity, suppressing astigmatism caused by eccentricity in the object-side lenses, thus correcting optical system aberrations and improving resolving power. Exemplarily, the optical system may further satisfy 1.751 ≤ F7 / F ≤ 2.189.

[0051] In an exemplary embodiment, the optical system satisfies: -4.897 ≤ F8 / F ≤ -1.391, where F8 is the effective focal length of the eighth lens, and F is the total effective focal length of the optical system. This configuration helps to widen the beam width, allowing larger-angle beams to be further widened after passing through the first to seventh lenses, ensuring that the wide beam is fully incident on the imaging surface of the optical system. This results in a wider field of view, which is beneficial for achieving large target imaging. Exemplarily, the optical system may further satisfy -4.452 ≤ F8 / F ≤ -1.546.

[0052] In an exemplary embodiment, the optical system satisfies: 1.659 ≤ F1_2 / F ≤ 4.660, where F1_2 is the effective focal length of the combination of the first and second lenses, and F is the total effective focal length of the optical system. This configuration allows light rays from each field of view to smoothly transition to the rear of the optical system, effectively balancing various aberrations produced by light passing through the front lens group, improving image quality, and simultaneously reducing the risk of ghosting and improving the lens's resolving quality. Exemplarily, the optical system may further satisfy 1.843 ≤ F1_2 / F ≤ 4.236.

[0053] In an exemplary embodiment, the optical system satisfies: 1.404 ≤ F3_8 / F ≤ 4.131, where F3_8 is the combined effective focal length of the third to eighth lenses, and F is the total effective focal length of the optical system. This setting helps control the direction of light, making the light travel more smoothly, reducing the system's sensitivity, improving the system's imaging quality, and also correcting the effect of field curvature generated by the front lens group on resolving power. Exemplarily, the optical system may further satisfy 1.560 ≤ F3_8 / F ≤ 3.755.

[0054] In an exemplary embodiment, the optical system satisfies: 0.193 ≤ F2 / F3 ≤ 0.726, where F2 is the effective focal length of the second lens and F3 is the effective focal length of the third lens. This configuration helps control the light path from the entry point of the optical system to the third lens, reducing aberrations caused by large-angle incoming light, while also making the lens structure compact and facilitating miniaturization. Exemplarily, the optical system may further satisfy 0.214 ≤ F2 / F3 ≤ 0.660.

[0055] In an exemplary embodiment, the optical system satisfies: -0.351 ≤ F5 / F6_8 ≤ -0.022, where F6_8 is the combined effective focal length of the sixth to eighth lenses, and F5 is the effective focal length of the fifth lens. This configuration effectively controls the light path, ensures the light transmission height at the rear of the lens, effectively balances the aberrations of the optical system, and achieves high resolution performance. Exemplarily, the optical system may further satisfy -0.319 ≤ F5 / F6_8 ≤ -0.024.

[0056] In an exemplary embodiment, the optical system satisfies: -1.297 ≤ F7 / F8 ≤ -0.443, where F7 is the effective focal length of the seventh lens and F8 is the effective focal length of the eighth lens. This setting helps eliminate residual higher-order aberrations in the optical system, improving lens resolution; it also effectively controls the light path, diverges light rays, and increases the light transmission height at the rear end, enabling the lens to effectively match a large-area chip and achieve a large-area effect. Exemplarily, the optical system may further satisfy -1.179 ≤ F7 / F8 ≤ -0.492.

[0057] In an exemplary embodiment, the optical system satisfies: -13.509 ≤ F8 / BFL ≤ -4.322, where F8 is the effective focal length of the eighth lens and BFL is the back focal length of the optical system. This setting facilitates sufficient light incidence onto the imaging plane of the optical lens, resulting in a wider field of view and facilitating large target imaging. Exemplarily, the optical system may further satisfy -12.281 ≤ F8 / BFL ≤ -4.802.

[0058] In an exemplary embodiment, the optical system satisfies: 0.006 ≤ T23 / F3 ≤ 0.062, where F3 is the effective focal length of the third lens, and T23 is the center distance from the image-side surface of the second lens to the object-side surface of the third lens. This setting facilitates the smooth arrival of light rays at the third lens after passing through the aperture stop, avoiding the introduction of unwanted stray light into the optical system and contributing to high resolution. Exemplarily, the optical system may further satisfy 0.007 ≤ T23 / F3 ≤ 0.056.

[0059] In an exemplary embodiment, the optical system satisfies: 0.488 ≤ R12 / R21 ≤ 0.960, where R12 is the radius of curvature of the image-side surface of the first lens, and R21 is the radius of curvature of the object-side surface of the second lens. This configuration allows for a smooth transition of light between the first and second lenses, thereby correcting axial chromatic aberration of the optical system and improving overall performance. Exemplarily, the optical system may further satisfy 0.542 ≤ R12 / R21 ≤ 0.873.

[0060] In an exemplary embodiment, the optical system satisfies: 0.202 ≤ T12 / TTL ≤ 0.267, where TTL is the total optical length of the optical system, and T12 is the center distance from the image-side surface of the first lens to the object-side surface of the second lens. This setting helps to shorten the total length of the optical system while ensuring high pixel imaging quality, thus minimizing the lens size. For example, the optical system may further satisfy 0.224 ≤ T12 / TTL ≤ 0.243.

[0061] In an exemplary embodiment, the optical system satisfies: 0.509 ≤ TTb / TTL ≤ 0.628, where TTb is the center distance from the image-side surface of the third lens to the image plane of the optical system, and TTL is the total optical length of the optical system. This configuration, by controlling the ratio of the center distance from the third lens to the image plane to the total length, helps to reduce the sensitivity of the optical system and improve image quality. For example, the optical system may further satisfy 0.566 ≤ TTb / TTL ≤ 0.571.

[0062] In an exemplary embodiment, the optical system satisfies: 2.164 ≤ TTL / F ≤ 2.814, where TTL is the total optical length of the optical system and F is the total effective focal length of the optical system. This setting limits the total optical length and total effective focal length of the optical system to a reasonable range, avoiding both insufficient spacing between the front and rear lens groups and optical path congestion due to an excessively short total optical length, and failure to meet the miniaturization requirements due to an excessively long total length. For example, the optical system may further satisfy 2.404 ≤ TTL / F ≤ 2.558.

[0063] In an exemplary embodiment, the optical system satisfies: 0.271 ≤ BFL / F ≤ 0.399, where BFL is the back focal length of the optical system and F is the total effective focal length of the optical system. This setting, while maintaining a constant system focal length, provides the optical system with a suitable back focal length, thereby reserving space for the installation and focusing of optical components, avoiding interference between mechanisms, and facilitating miniaturization. Exemplarily, the optical system may further satisfy 0.301 ≤ BFL / F ≤ 0.363.

[0064] In an exemplary embodiment, the optical system satisfies: 0.551 ≤ D1 / TTL ≤ 0.730, where D1 is the effective aperture of the object side of the first lens, and TTL is the total optical length of the optical system. This setting facilitates control over the ratio of the total optical length to the aperture of the first lens, allowing the entire optical system to be more compact and miniaturized. For example, the optical system may further satisfy 0.612 ≤ D1 / TTL ≤ 0.664.

[0065] In an exemplary embodiment, the optical system satisfies: 2.876 ≤ IH / D3 ≤ 4.534, where IH is the full image height of the optical system and D3 is the effective aperture of the object-side surface of the third lens. This setting facilitates the entry of large-angle light into the system, thereby achieving a large field of view, and also helps to increase the light transmission of the system, better realizing a large aperture of the lens. Exemplarily, the optical system may further satisfy 3.195 ≤ IH / D3 ≤ 4.122.

[0066] In an exemplary embodiment, the optical system satisfies: 0.122 ≤ R82 / IH ≤ 0.219, where R82 is the radius of curvature of the image-side surface of the eighth lens, and IH is the total image height of the optical system. This setting effectively controls the light path, increases the light transmission height, and allows the light to transition smoothly to the image plane, which is beneficial for achieving a large target surface and reducing the tolerance sensitivity of the optical system. For example, the optical system may further satisfy 0.135 ≤ R82 / IH ≤ 0.199.

[0067] In an exemplary embodiment, the optical system satisfies: -3.158 ≤ R72 / R81 ≤ 8.273, where R72 is the radius of curvature of the image-side surface of the seventh lens, and R81 is the radius of curvature of the object-side surface of the eighth lens. This setting effectively controls the light path, elevates the light beam, and helps to better match the light beam to the chip size; it also helps to achieve lens miniaturization. Exemplarily, the optical system may further satisfy -2.871 ≤ R72 / R81 ≤ 7.521.

[0068] In an exemplary embodiment, the optical system satisfies: 5.995 mm -1 ≤(Vd3+Vd4+Vd5) / F3_5≤14.313mm -1 Where Vd3 is the Abbe number of the third lens, Vd4 is the Abbe number of the fourth lens, Vd5 is the Abbe number of the fifth lens, and F3_5 is the combined effective focal length of the third to fifth lenses. This configuration, through the appropriate combination of lens materials, can effectively balance the chromatic aberration of the optical system and achieve high lens resolution. For example, the optical system can further meet the requirement of 6.661mm. -1 ≤(Vd3+Vd4+Vd5) / F3_5≤13.012 mm -1 .

[0069] In exemplary embodiments, this application utilizes a combination of spherical and aspherical lenses, which helps reduce the manufacturing difficulty of the lenses; simultaneously, through material selection, a heat-free design can be achieved. This application does not specifically limit the number of spherical and aspherical lenses. When focusing on image quality, the number of aspherical lenses can be increased, or even all lenses can be aspherical. Aspherical lenses are characterized by a continuously changing curvature from the lens center to the periphery. Unlike spherical lenses, which have a constant curvature from the lens center to the periphery, aspherical lenses have better curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving the image quality of the lens. However, those skilled in the art should understand that, without departing from the technical solutions claimed in this application, the lens surface type constituting the optical system can be changed to obtain the various results and advantages described in this specification. Exemplarily, in this application, the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are all aspherical lenses.

[0070] Those skilled in the art will understand that plastics have a large temperature coefficient of refractive index (dn / dt) and anomalous dispersion. A suitable amount of plastic material is beneficial for high and low temperature balance, but excessive plastic lenses are detrimental to system stability. Optical lenses made of glass can suppress the shift of the back focus of the optical system with temperature changes, thereby improving system stability. At the same time, using glass avoids lens blurring caused by high and low temperature changes in the operating environment, thus preventing problems affecting the normal use of the lens. Using glass also facilitates heat-free lens operation. Furthermore, using glass can better correct chromatic aberration, improve lens resolution, and reduce ghosting. As an example, in this application, the first, third, fourth, fifth, sixth, seventh, and eighth lenses are all made of plastic, while the second lens is made of glass. This arrangement allows the optical system to operate over a wide temperature range, maintaining stable optical performance even within a wide range of high and low temperature variations.

[0071] In an exemplary embodiment, the optical system of this application employs a combination of six plastic lenses and one glass lens. On the one hand, plastic lenses are lighter than glass lenses, and the extensive use of plastic lenses can significantly reduce the overall weight of the lens, achieving a lightweight design and facilitating overall lens miniaturization. On the other hand, by utilizing the differences in the coefficients of thermal expansion and temperature coefficients of refractive index between plastic and glass materials, and by rationally allocating the optical power of the six plastic lenses and one glass lens, refractive index drift caused by temperature changes and lens thermal expansion and contraction deformation can be compensated for. This effectively suppresses image plane shift caused by high and low temperature environments, achieving excellent pyrolysis performance of the lens and ensuring stable imaging quality in a wide temperature range.

[0072] The optical system of this application may further include an aperture stop for limiting the light beam. The aperture stop helps to concentrate the light entering the optical system, reduce the maximum aperture of the optical system, and balance the off-axis aberrations of the optical system, thereby further improving the imaging quality of the optical system. It should be noted that the aperture stop can be placed between or on one side of any lens, depending on actual needs. For example, the aperture stop is placed between the second lens and the third lens.

[0073] In an exemplary embodiment, the total optical length (TTL) of the optical system of this application can satisfy: TTL≤15.1mm, which results in a short total optical length, compact structure, and miniaturization of the lens. Exemplarily, the total optical length (TTL) of the optical system can further satisfy: 13.9mm≤TTL≤15.1mm.

[0074] In an exemplary embodiment, the maximum field of view (FOV) of the optical system of this application satisfies: FOV = 102°, which ensures that the optical system has a large field of view, effectively increasing the shooting range of the optical system and improving the practical application value of the product. For example, the FOV of the optical system can further satisfy: 98° ≤ FOV ≤ 102°.

[0075] In an exemplary embodiment, the aperture value FNO of the optical system of this application can satisfy: FNO≤2.1, which ensures that the optical system has a large aperture characteristic, enabling the lens to have a large amount of light transmission. Exemplarily, the aperture FNO of the optical system can further satisfy: 1.65≤FNO≤2.1.

[0076] In an exemplary embodiment, the absolute distortion value DIS of the optical system of this application can satisfy: DIS≤3.2%, which can ensure that the optical system has low distortion characteristics. Exemplarily, the absolute distortion value DIS of the optical system can further satisfy: 0%≤DIS≤3.2%.

[0077] In an exemplary embodiment, the holographic height IH of the optical system of this application can satisfy: IH ≥ 14.0 mm, which can ensure that the optical system has the characteristic of a large target surface. Exemplarily, the holographic height IH of the optical system can further satisfy: 14.0 mm ≤ DIS ≤ 14.2 mm.

[0078] Alternatively, in other alternative exemplary embodiments, the optical system described above may also be supplemented with filters for correcting color deviations and / or protective glass for protecting the photosensitive element located on the imaging surface.

[0079] However, those skilled in the art will understand that the number of lenses constituting the optical system can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although an embodiment has been described using eight lenses as an example, the optical system is not limited to including eight lenses. If desired, the optical system may also include other numbers of lenses.

[0080] Specific embodiments of the optical system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0081] Example 1

[0082] Figure 1 A schematic diagram of the optical system according to Embodiment 1 of this application is shown. Figure 1 As shown, the optical system includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0083] The first lens L1 has negative optical power, with its object side being convex and its image side being concave.

[0084] The second lens L2 has positive optical power, with its object side being convex and its image side being concave.

[0085] The third lens L3 has positive optical power, with a convex object side and a concave image side.

[0086] The fourth lens L4 has negative optical power, with a convex object side and a concave image side.

[0087] The fifth lens L5 has positive optical power, and its object side and image side are both convex.

[0088] The sixth lens L6 has negative optical power, with a convex object side and a concave image side.

[0089] The seventh lens L7 has positive optical power, with a convex object side and a concave image side.

[0090] The eighth lens L8 has negative optical power, with a convex object side and a concave image side.

[0091] The optical system also includes an aperture stop STO, which can be positioned between the second lens L2 and the third lens L3.

[0092] The optical system may also include a filter (not shown) having an object-side and an image-side surface and / or a protective glass CG having an object-side and an image-side surface. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through the surfaces and is ultimately imaged onto the imaging surface IMA.

[0093] Table 1 shows the basic parameters of the optical system of Example 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0094] Table 1

[0095] S1 aspherical 9.388 1.125 1.535 55.71 S2 aspherical 3.266 2.567 S3 aspherical 3.740 1.343 1.694 53.20 S4 aspherical 23.168 0.164 STO spherical Infinity 0.057 S5 aspherical 11.079 0.759 1.535 55.71 S6 aspherical 37.009 0.036 S7 aspherical 20.845 0.656 1.671 19.28 S8 aspherical 6.532 0.172 S9 aspherical 5.909 1.219 1.535 55.71 S10 aspherical -395.787 0.555 S11 aspherical 11.801 0.675 1.671 19.28 S12 aspherical 6.180 0.242 S13 aspherical 5.400 1.029 1.535 55.71 S14 aspherical 30.687 0.205 S15 aspherical 4.080 1.182 1.535 55.71 S16 aspherical 2.798 1.315 S17 spherical Infinity 0.236 1.517 64.20 S18 spherical Infinity 0.439 IMA spherical Infinity -

[0096] In Example 1, the object-side and image-side surfaces of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are all aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0097] (1);

[0098] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror in Example 1.

[0099] Table 2

[0100]

[0101] Example 2

[0102] Figure 2 A schematic diagram of the optical system of Embodiment 2 of this application is shown. Figure 2 As shown, the optical system includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0103] The first lens L1 has negative optical power, with its object side being convex and its image side being concave.

[0104] The second lens L2 has positive optical power, with its object side being convex and its image side being concave.

[0105] The third lens L3 has positive optical power, and its object side and image side are both convex.

[0106] The fourth lens L4 has negative optical power, with a convex object side and a concave image side.

[0107] The fifth lens L5 has positive optical power, and its object side and image side are both convex.

[0108] The sixth lens L6 has negative optical power, with a convex object side and a concave image side.

[0109] The seventh lens L7 has positive optical power, and its object side and image side are both convex.

[0110] The eighth lens L8 has negative optical power, with a convex object side and a concave image side.

[0111] The optical system also includes an aperture stop STO, which can be positioned between the second lens L2 and the third lens L3. The optical system may also include a filter (not shown) having an object-side and an image-side surface and / or a protective glass CG having an object-side and an image-side surface. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through the surfaces and is ultimately imaged onto the imaging surface IMA.

[0112] Table 3 shows the basic parameters of the optical system of Example 2, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0113] Table 3

[0114] S1 aspherical 10.447 0.818 1.535 55.71 S2 aspherical 3.657 2.840 S3 aspherical 5.632 1.150 1.694 53.20 S4 aspherical 125.280 0.794 STO spherical Infinity 0.056 S5 aspherical 8.257 0.869 1.535 55.71 S6 aspherical -628.521 0.380 S7 aspherical 59.360 0.587 1.671 19.28 S8 aspherical 7.982 0.105 S9 aspherical 7.094 0.978 1.535 55.71 S10 aspherical -30.294 1.174 S11 aspherical 8.256 0.706 1.671 19.28 S12 aspherical 5.953 0.645 S13 aspherical 14.168 1.132 1.535 55.71 S14 aspherical -9.885 0.070 S15 aspherical 3.554 0.884 1.535 55.71 S16 aspherical 2.060 1.485 S17 spherical Infinity 0.210 1.517 64.20 S18 spherical Infinity 0.150 IMA spherical Infinity -

[0115] In Example 2, the object-side and image-side surfaces of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are all aspherical. The surface shape of each aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above. Table 4 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror in Example 2.

[0116] Table 4

[0117]

[0118] Example 3

[0119] Figure 3 A schematic diagram of the optical system of Embodiment 3 of this application is shown. Figure 3 As shown, the optical system includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0120] The first lens L1 has negative optical power, with its object side being convex and its image side being concave.

[0121] The second lens L2 has positive optical power, and its object side and image side are both convex.

[0122] The third lens L3 has positive optical power, and its object side and image side are both convex.

[0123] The fourth lens L4 has negative optical power, and its object side and image side are both concave.

[0124] The fifth lens L5 has positive optical power, and its object side and image side are both convex.

[0125] The sixth lens L6 has negative optical power, with a convex object side and a concave image side.

[0126] The seventh lens L7 has positive optical power, and its object side and image side are both convex.

[0127] The eighth lens L8 has negative optical power, with a convex object side and a concave image side.

[0128] The optical system also includes an aperture stop STO, which can be positioned between the second lens L2 and the third lens L3. The optical system may also include a filter (not shown) having an object-side and an image-side surface and / or a protective glass CG having an object-side and an image-side surface. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through the surfaces and is ultimately imaged onto the imaging surface IMA.

[0129] Table 5 shows the basic parameters of the optical system of Example 3, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0130] Table 5

[0131] S1 aspherical 9.874 0.842 1.535 55.71 S2 aspherical 3.359 2.588 S3 aspherical 6.111 1.348 1.694 53.20 S4 aspherical -17.310 0.533 STO spherical Infinity 0.057 S5 aspherical 16.603 1.055 1.535 55.71 S6 aspherical -34.909 0.412 S7 aspherical -115.507 0.603 1.671 19.28 S8 aspherical 9.213 0.071 S9 aspherical 6.899 1.173 1.535 55.71 S10 aspherical -59.872 1.063 S11 aspherical 11.246 0.705 1.671 19.28 S12 aspherical 7.836 0.626 S13 aspherical 13.022 1.005 1.535 55.71 S14 aspherical -11.476 0.131 S15 aspherical 4.132 0.898 1.535 55.71 S16 aspherical 2.137 1.601 S17 spherical Infinity 0.210 1.517 64.20 S18 spherical Infinity 0.050 IMA spherical Infinity -

[0132] In Example 3, the object-side and image-side surfaces of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are all aspherical. The surface shape of each aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above. Table 6 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror in Example 3.

[0133] Table 6

[0134]

[0135] Example 4

[0136] Figure 4 A schematic diagram of the optical system of Embodiment 4 of this application is shown. Figure 4 As shown, the optical system includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0137] The first lens L1 has negative optical power, with its object side being convex and its image side being concave.

[0138] The second lens L2 has positive optical power, and its object side and image side are both convex.

[0139] The third lens L3 has positive optical power, and its object side and image side are both convex.

[0140] The fourth lens L4 has negative optical power, and its object side and image side are both concave.

[0141] The fifth lens L5 has positive optical power, and its object side and image side are both convex.

[0142] The sixth lens L6 has negative optical power, with a convex object side and a concave image side.

[0143] The seventh lens L7 has positive optical power, and its object side and image side are both convex.

[0144] The eighth lens L8 has negative optical power, with a convex object side and a concave image side.

[0145] The optical system also includes an aperture stop STO, which can be positioned between the second lens L2 and the third lens L3. The optical system may also include a filter (not shown) having an object-side and an image-side surface and / or a protective glass CG having an object-side and an image-side surface. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through the surfaces and is ultimately imaged onto the imaging surface IMA.

[0146] Table 7 shows the basic parameters of the optical system of Example 4, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0147] Table 7

[0148] S1 aspherical 10.273 0.876 1.535 55.71 S2 aspherical 3.362 2.606 S3 aspherical 6.206 1.349 1.694 53.20 S4 aspherical -16.748 0.535 STO spherical Infinity 0.057 S5 aspherical 16.549 1.059 1.535 55.71 S6 aspherical -36.567 0.396 S7 aspherical -118.630 0.598 1.671 19.28 S8 aspherical 9.127 0.071 S9 aspherical 6.960 1.023 1.535 55.71 S10 aspherical -71.747 1.049 S11 aspherical 10.902 0.680 1.671 19.28 S12 aspherical 7.563 0.552 S13 aspherical 12.780 1.039 1.535 55.71 S14 aspherical -10.561 0.137 S15 aspherical 4.189 0.974 1.535 55.71 S16 aspherical 2.129 1.750 S17 spherical Infinity 0.210 1.517 64.20 S18 spherical Infinity 0.050 IMA spherical Infinity -

[0149] In Example 4, the object-side and image-side surfaces of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are all aspherical. The surface shape of each aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above. Table 8 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror in Example 4.

[0150] Table 8

[0151]

[0152] Example 5

[0153] Figure 5A schematic diagram of the optical system of Embodiment 5 of this application is shown. Figure 5 As shown, the optical system includes, in sequence along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0154] The first lens L1 has negative optical power, with its object side being convex and its image side being concave.

[0155] The second lens L2 has positive optical power, with its object side being convex and its image side being concave.

[0156] The third lens L3 has positive optical power, with a convex object side and a concave image side.

[0157] The fourth lens L4 has negative optical power, with a convex object side and a concave image side.

[0158] The fifth lens L5 has positive optical power, and its object side and image side are both convex.

[0159] The sixth lens L6 has negative optical power, with a convex object side and a concave image side.

[0160] The seventh lens L7 has positive optical power, and its object side and image side are both convex.

[0161] The eighth lens L8 has negative optical power, with a convex object side and a concave image side.

[0162] The optical system also includes an aperture stop STO, which can be positioned between the second lens L2 and the third lens L3. The optical system may also include a filter (not shown) having an object-side and an image-side surface and / or a protective glass CG having an object-side and an image-side surface. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through the surfaces and is ultimately imaged onto the imaging surface IMA.

[0163] Table 9 shows the basic parameters of the optical system of Example 5, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0164] Table 9

[0165] S1 aspherical 9.795 0.980 1.537 55.98 S2 aspherical 3.441 2.245 S3 aspherical 5.870 1.147 1.694 53.20 S4 aspherical 250.795 0.603 STO spherical Infinity 0.059 S5 aspherical 6.915 0.877 1.535 55.71 S6 aspherical 461.276 0.400 S7 aspherical 48.157 0.624 1.661 20.38 S8 aspherical 7.060 0.098 S9 aspherical 6.084 1.202 1.535 55.71 S10 aspherical -29.773 0.976 S11 aspherical 8.030 0.704 1.671 19.28 S12 aspherical 5.837 0.552 S13 aspherical 15.691 1.083 1.537 55.98 S14 aspherical -9.155 0.076 S15 aspherical 3.189 0.836 1.537 55.98 S16 aspherical 1.905 1.593 S17 spherical Infinity 0.210 1.517 64.20 S18 spherical Infinity 0.050 IMA spherical Infinity -

[0166] In Example 5, the object-side and image-side surfaces of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are all aspherical. The surface shape of each aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above. Table 10 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror in Example 5.

[0167] Table 10

[0168]

[0169] In summary, the optical systems in Examples 1 to 5 satisfy the relationships shown in Table 11. In each example, the parameter Vd of the optical system has no unit, while the units for other parameters are millimeters (mm).

[0170] Table 11

[0171]

[0172] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the concept of this application. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical system, characterized in that, Along the optical axis from the object side to the image side, the following are included in sequence: A first lens with negative optical power; A second lens with positive optical power; A third lens with positive optical power; A fourth lens with negative optical power; A fifth lens with positive optical power; A sixth lens with negative optical power; A seventh lens with positive optical power; An eighth lens with negative optical power; The optical system has eight lenses with optical power. The optical system satisfies the following condition: -4.897≤F8 / F≤-1.391; where F is the total effective focal length of the optical system and F8 is the effective focal length of the eighth lens.

2. The optical system according to claim 1, characterized in that: The object-side surface of the first lens is convex, and the image-side surface is concave. The second lens has a convex side and an image side that is concave, convex, or flat. The object side of the third lens is convex, and the image side is concave, convex, or flat. The fourth lens has a convex, concave, or flat surface on the object side and a concave surface on the image side. The object side of the fifth lens is convex, and the image side is either convex, concave, or flat. The object side of the sixth lens is convex, and the image side is concave. The object side of the seventh lens is convex, and the image side is either convex or concave. The object side of the eighth lens is convex, and the image side is concave.

3. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: -2.034≤F1 / F≤-1.402; 0.960≤F² / F≤1.636; 2.027≤F3 / F≤5.831; -2.859≤F4 / F≤-1.795; 1.477≤F5 / F≤2.171; -7.389≤F6 / F≤-3.290; 1.576≤F7 / F≤2.408; Wherein, F1 is the effective focal length of the first lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, F4 is the effective focal length of the fourth lens, F5 is the effective focal length of the fifth lens, F6 is the effective focal length of the sixth lens, and F7 is the effective focal length of the seventh lens.

4. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: 1.659≤F1_2 / F≤4.660; 1.404≤F3_8 / F≤4.131; 0.193≤F2 / F3≤0.726; -0.351≤F5 / F6_8≤-0.022; -1.297≤F7 / F8≤-0.443; Wherein, F1_2 is the combined effective focal length value of the first lens and the second lens, F3_8 is the combined effective focal length value of the third lens to the eighth lens, F2 is the effective focal length value of the second lens, F3 is the effective focal length value of the third lens, F5 is the effective focal length value of the fifth lens, F6_8 is the combined effective focal length value of the sixth lens to the eighth lens, and F7 is the effective focal length value of the seventh lens.

5. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: -13.509≤F8 / BFL≤-4.322; 0.006≤T23 / F3≤0.062; 2.876≤IH / D3≤4.534; 0.122≤R82 / IH≤0.219; Wherein, BFL is the back focal length of the optical system, T23 is the center distance from the image side of the second lens to the object side of the third lens, F3 is the effective focal length of the third lens, IH is the total image height of the optical system, D3 is the effective aperture of the object side of the third lens, and R82 is the radius of curvature of the image side of the eighth lens.

6. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: 0.488≤R12 / R21≤0.960; -3.158≤R72 / R81≤8.273; Wherein, R12 is the radius of curvature of the image side of the first lens, R21 is the radius of curvature of the object side of the second lens, R72 is the radius of curvature of the image side of the seventh lens, and R81 is the radius of curvature of the object side of the eighth lens.

7. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: 0.202≤T12 / TTL≤0.267; 0.509≤TTb / TTL≤0.628; 2.164≤TTL / F≤2.814; 0.271≤BFL / F≤0.399; 0.551≤D1 / TTL≤0.730; Wherein, T12 is the center distance from the image side of the first lens to the object side of the second lens, TTb is the center distance from the image side of the third lens to the image plane of the optical system, TTL is the total optical length of the optical system, BFL is the back focal length of the optical system, and D1 is the effective aperture of the object side of the first lens.

8. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies the following condition: 5.995 mm -1 ≤(Vd3+Vd4+Vd5) / F3_5≤14.313 mm -1 ; Wherein, Vd3 is the Abbe number of the third lens, Vd4 is the Abbe number of the fourth lens, Vd5 is the Abbe number of the fifth lens, and F3_5 is the combined effective focal length value of the third to the fifth lenses.

9. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: -1.849≤F1 / F≤-1.558; 1.067≤F² / F≤1.487; 2.252≤F3 / F≤5.301; -2.599≤F4 / F≤-1.994; 1.641≤F5 / F≤1.974; -6.717≤F6 / F≤-3.656; 1.751≤F7 / F≤2.189; -4.452≤F8 / F≤-1.546; 1.843≤F1_2 / F≤4.236; 1.560≤F3_8 / F≤3.755; 0.214≤F2 / F3≤0.660; -0.319≤F5 / F6_8≤-0.024; -1.179≤F7 / F8≤-0.492; Wherein, F1 is the effective focal length of the first lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, F4 is the effective focal length of the fourth lens, F5 is the effective focal length of the fifth lens, F6 is the effective focal length of the sixth lens, F7 is the effective focal length of the seventh lens, F1_2 is the combined effective focal length of the first lens and the second lens, F3_8 is the combined effective focal length of the third lens to the eighth lens, and F6_8 is the combined effective focal length of the sixth lens to the eighth lens.

10. The optical system according to claim 1 or 2, characterized in that, The optical system satisfies at least one of the following conditions: -12.281≤F8 / BFL≤-4.802; 0.007≤T23 / F3≤0.056; 0.542≤R12 / R21≤0.873; 0.224≤T12 / TTL≤0.243; 0.566≤TTb / TTL≤0.571; 2.404≤TTL / F≤2.558; 0.301≤BFL / F≤0.363; 0.612≤D1 / TTL≤0.664; 3.195≤IH / D3≤4.122; 0.135≤R82 / IH≤0.199; -2.871≤R72 / R81≤7.521; 6.661 mm -1 ≤(Vd3+Vd4+Vd5) / F3_5≤13.012 mm -1 ; Wherein, BFL is the back focal length of the optical system, T23 is the center distance from the image-side surface of the second lens to the object-side surface of the third lens, F3 is the effective focal length of the third lens, R12 is the radius of curvature of the image-side surface of the first lens, R21 is the radius of curvature of the object-side surface of the second lens, T12 is the center distance from the image-side surface of the first lens to the object-side surface of the second lens, TTL is the total optical length of the optical system, TTb is the center distance from the image-side surface of the third lens to the image plane of the optical system, and D1 is the... The effective aperture of the object side of the first lens, IH is the total image height of the optical system, D3 is the effective aperture of the object side of the third lens, R72 is the radius of curvature of the image side of the seventh lens, R81 is the radius of curvature of the object side of the eighth lens, R82 is the radius of curvature of the image side of the eighth lens, Vd3 is the Abbe number of the third lens, Vd4 is the Abbe number of the fourth lens, Vd5 is the Abbe number of the fifth lens, and F3_5 is the combined effective focal length of the third to the fifth lenses.

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