Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses in total, and sequentially comprises a front group with positive focal power and a rear group with positive focal power from an object side to an imaging surface along an optical axis, the front group sequentially comprises a first lens with negative focal power from the object side to the imaging surface along the optical axis, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; the rear group sequentially comprises a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power from the object side to the imaging surface along the optical axis; the fourth lens has positive focal power; the fifth lens has negative focal power; the sixth lens has positive focal power; the seventh lens has negative focal power; and the eighth lens has negative focal power. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the imaging quality of the optical lens can be improved, and the optical lens has the advantage of excellent imaging quality.

Description

Technical Field

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

[0002] In modern video conferencing systems, high-quality image transmission is crucial. Most video conferencing lenses on the current market adopt fixed-focus or zoom designs to meet the requirements of different application scenarios. However, these traditional lenses often have problems of relatively large volume and heavy weight, which not only limit the miniaturization design of the devices but also increase the manufacturing cost. Therefore, there is an urgent need to provide an optical lens that can meet the usage requirements of video conferencing, taking into account miniaturization and excellent imaging quality. Summary of the Invention

[0003] Aiming at the above problems, the purpose of the present invention is to provide an optical lens with the advantage of excellent imaging quality.

[0004] The present invention provides an optical lens, which has a total of eight lenses and sequentially includes, along the optical axis from the object side to the imaging surface: a front group with positive optical power and a rear group with positive optical power; The front group sequentially includes, along the optical axis from the object side to the imaging surface: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with positive optical power, whose object side is convex and whose image side is convex; The rear group sequentially includes, along the optical axis from the object side to the imaging surface: A third lens with positive optical power, whose object side is convex and whose image side is concave; A fourth lens with positive optical power, whose object side is convex and whose image side is convex; A fifth lens with negative optical power, whose image side is concave; A sixth lens with positive optical power, whose object side is convex and whose image side is convex; A seventh lens with negative optical power, whose object side is concave and whose image side is convex; An eighth lens with negative optical power, whose object side is concave; Among them, the combined focal length fa of the front group and the combined focal length fb of the rear group satisfy: 1.2 < fa / fb < 3.2.

[0005] Further preferably, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 60° < (f × FOV) / IH < 70°.

[0006] More preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.5 < TTL / f < 3; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.5 < TTL / IH < 1.7.

[0007] More preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5 < f1 / f < -1.5.

[0008] More preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.5 < f2 / f < 2; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -1.5 < R3 / R4 < -0.5.

[0009] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2 < f3 / f < 6; 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: 0.3 < R5 / R6 < 0.8.

[0010] More preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.5 < f4 / f < 2; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -1.2.

[0011] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.9 < f6 / f < 1.35; the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -8 < f7 / f < -3.

[0012] More preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -1.5 < f8 / f < -0.9.

[0013] More preferably, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -1.5 < f1 / f2 < -0.8.

[0014] More preferably, the distance CT12 between the first lens and the second lens on the optical axis, the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 1.15 < CT12 / (CT1 + CT2) < 2.

[0015] More preferably, the clear aperture DM11 of the object side surface of the first lens and the clear aperture DM82 of the image side surface of the eighth lens satisfy: 1.1 < DM11 / DM82 < 1.3.

[0016] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers. 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, enabling the lens to have one or more advantages such as miniaturization, large aperture, large image height, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where: Figure 1 It is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 2 It is an astigmatism curve diagram of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 3 It is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 4 It is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0021] Figure 5 It is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0022] Figure 6 It is an astigmatism curve diagram of the optical lens in Embodiment 2 of the present invention.

[0023] Figure 7 It is an axial aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 8 It is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 9 It is a schematic structural diagram of the optical lens in Embodiment 3 of the present invention.

[0026] Figure 10 It is an astigmatism curve diagram of the optical lens in Embodiment 3 of the present invention.

[0027] Figure 11 It is an axial aberration curve diagram of the optical lens in Embodiment 3 of the present invention.

[0028] Figure 12 It is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 3 of the present invention.

[0029] Figure 13 It is a schematic structural diagram of the optical lens in Embodiment 4 of the present invention.

[0030] Figure 14 This is the astigmatism curve graph of the optical lens in Embodiment 4 of the present invention.

[0031] Figure 15 This is the axial aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0032] Figure 16 This is the lateral chromatic aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0033] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0034] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application and do not limit the scope of the present 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.

[0035] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature and do not represent any limitation on the feature. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0036] In the drawings, for the sake of clarity, the thickness, dimensions, and shape of the lenses have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn to an exact scale.

[0037] In this document, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface 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 object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0038] It should also be understood that the terms "comprise", "comprises", "include", "includes", "have", "has", "contain" and / or "contains", when used in this specification, denote the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. Further, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features rather than individual elements in the list. Further, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0040] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0041] The optical lens provided by the embodiment of the present invention has a total of eight lenses, and sequentially includes, along the optical axis from the object side to the imaging surface: a front group with a positive optical power and a rear group with a positive optical power.

[0042] Specifically, the front group sequentially includes, along the optical axis from the object side to the imaging surface: a first lens and a second lens. The first lens may have a negative optical power, its object side is convex, and its image side is concave. The second lens may have a positive optical power, its object side is convex, and its image side is convex.

[0043] The rear group sequentially includes, along the optical axis from the object side to the imaging surface: a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens. The third lens may have a positive optical power, its object side is convex, and its image side is concave. The fourth lens may have a positive optical power, its object side is convex, and its image side is convex. The fifth lens may have a negative optical power, its object side may be concave or convex, and its image side is concave. The sixth lens may have a positive optical power, its object side is convex, and its image side is convex. The seventh lens may have a negative optical power, its object side is concave, and its image side is convex. The eighth lens may have a negative optical power, its object side is concave, and its image side may be concave or convex.

[0044] In some embodiments, the optical lens may further include a diaphragm, which may be located between the second lens and the third lens, i.e., between the front group and the rear group. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image. At the same time, a diaphragm for limiting the light beam is provided between the front group and the rear group, which can reduce the generation of ghosts in the optical lens, is conducive to converging the light entering the optical system, reducing the aperture of the rear port of the optical lens, and the diaphragm arranged here also enables the optical lens to have a larger aperture, improving the light input of the lens and enabling the lens to achieve high-definition imaging even in a dim environment.

[0045] In some embodiments, the optical lens may further include a filter, which is disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0046] In some embodiments, the combined focal length fa of the front group and the combined focal length fb of the rear group satisfy: 1.2 < fa / fb < 3.2. Meeting the above conditions, by reasonably setting the focal length relationship between the lens groups before and after the diaphragm, on the one hand, it is conducive to the incidence of light, enabling the light entering the system from the front end to smoothly enter the rear optical system, making the overall light path more gentle, and on the other hand, it is conducive to optimizing aberrations and improving the overall resolution of the lens.

[0047] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 60° < (f × FOV) / IH < 70°. Meeting the above conditions can effectively balance the requirements of large-angle imaging and high-definition imaging, and improve the adaptability of the optical lens in different application scenarios.

[0048] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.5 < TTL / f < 3. Meeting the above conditions can effectively limit the length of the lens, which is conducive to realizing the miniaturization of the optical lens.

[0049] In some embodiments, the overall 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: 1.5 < TTL / IH < 1.7. Meeting the above conditions can better realize the miniaturization of the lens, and at the same time ensure that the lens has a larger image plane under the condition of the same overall length of the lens, and can match a larger-sized imaging chip to achieve high-definition imaging.

[0050] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5 < f1 / f < -1.5. Meeting the above conditions can make the first lens have a large negative refractive power, can receive as much light as possible into the system to a large extent, and is conducive to increasing the field of view angle of the optical lens.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.5 < f2 / f < 2. By satisfying the above conditions and setting the second lens to have a relatively large positive refractive power, the light entering the system can be effectively converged, the light collection ability of the peripheral field of view can be improved, and the overall imaging quality can be enhanced.

[0052] In some embodiments, the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: -1.5 < R3 / R4 < -0.5. By satisfying the above conditions and reasonably setting the biconvex surface type of the second lens, it is beneficial to receive light rays incident at large angles and control the incident light rays to enter the optical system more gently, thereby reducing the tolerance sensitivity of the optical system.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2 < f3 / f < 6; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.5 < f4 / f < 2. By satisfying the above conditions and setting the positive refractive powers of the third and fourth lenses, the incident light rays at the front end can be effectively converged, which is beneficial to correcting the aberration and distortion of the peripheral field of view caused by the front-end lenses, enabling the lens to have less distortion and providing a high-definition imaging effect.

[0054] In some embodiments, the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: 0.3 < R5 / R6 < 0.8. By satisfying the above conditions, it is beneficial to better achieve the convergence of light rays, shorten the distance for the light rays to reach the next lens, and is beneficial to reducing the total length of the optical lens.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -1.2. By satisfying the above conditions, the fifth lens can have a relatively large negative refractive power, which can cause the light rays to diverge appropriately, is beneficial to increasing the imaging area of the optical lens, and enhancing the imaging quality of the optical lens.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.9 < f6 / f < 1.35; the curvature radius R11 of the object side surface of the sixth lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: -1.8 < R11 / R12 < -1. By satisfying the above conditions, the sixth lens can have an appropriate positive optical power and a suitable surface type, which is beneficial to the smooth transition of light rays, and at the same time balances the spherical aberration and field curvature of the fifth lens, enhancing the imaging quality of the optical lens.

[0057] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -8 < f7 / f < -3; the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: 0.35 < R13 / R14 < 0.85. Meeting the above conditions, by reasonably setting the focal length of the seventh lens and the appropriate surface shape, the light rays in the marginal field of view can be effectively diverged. At the same time, combined with the bending of the edge region of the eighth lens, the exit angle of the light rays in the marginal field of view can be reduced, and the relative illuminance of the marginal field of view can be improved.

[0058] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -1.5 < f8 / f < -0.9. Meeting the above conditions, by setting the eighth lens to have a large negative optical power, the incident light rays can be diverged to a large extent, causing the peripheral light rays and the central light rays to turn upwards and reach a higher imaging position, better realizing the large target surface imaging of the lens and improving the imaging quality.

[0059] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -1.5 < f1 / f2 < -0.8. Meeting the above conditions, by reasonably distributing the focal length relationship between the first and second lenses, the object surface light with a wide field of view can be converged into the lens, which is beneficial to achieving the balance of the large field of view and the large aperture of the optical lens.

[0060] In some embodiments, the distance CT12 between the first lens and the second lens on the optical axis, the central thickness CT1 of the first lens, and the central thickness CT2 of the second lens satisfy: 1.15 < CT12 / (CT1 + CT2) < 2. Meeting the above conditions, by setting a large air gap between the first and second lenses, the incident light rays can be smoothly transitioned. At the same time, it is beneficial to correct the aberration brought by the first lens and improve the imaging quality of the optical lens.

[0061] In some embodiments, the clear aperture DM11 of the object side surface of the first lens and the clear aperture DM82 of the image side surface of the eighth lens satisfy: 1.1 < DM11 / DM82 < 1.3. Meeting the above conditions, the lens can have a large incident aperture. While ensuring that as much light as possible enters the system, the area of the light entering the imaging surface is increased, which is beneficial to achieving the balance of the large image surface and the large aperture of the lens.

[0062] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the f-number Fno of the optical lens satisfy: 5.3 mm < IH / Fno < 6 mm. Meeting the above conditions, the lens can have a large aperture and a large imaging target surface, ensuring that the lens also has a large light flux in a relatively dark environment, thereby improving the picture quality of the lens in different environments.

[0063] In some embodiments, the combined focal length fa of the front group and the effective focal length f of the optical lens satisfy: 3 < fa / f < 5.7. Meeting the above conditions, by setting the front group before the aperture to have appropriate positive refractive power, the object surface light with a wide field of view can be converged into the lens, better correcting the edge distortion of the lens without generating large aberrations.

[0064] In some embodiments, the combined focal length fb of the rear group and the effective focal length f of the optical lens satisfy: 1.6 < fb / f < 2.5. Meeting the above conditions, by setting the rear group after the aperture to have large positive refractive power, it is beneficial to balance the distortion and astigmatism generated by the front lens of the optical lens, improving the imaging quality of the optical lens.

[0065] In some embodiments, the focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy: 2.5 < f7 / f8 < 7.5. Meeting the above conditions, by reasonably setting the focal length relationship between the seventh and eighth lenses, the light rays in the edge field of view can be effectively diverged. At the same time, combined with the curvature of the edge region of the eighth lens, the exit angle of the light rays in the edge field of view is reduced, improving the relative illumination of the edge field of view.

[0066] In some embodiments, the optical lens satisfies the conditional formula: 6.2 mm < f < 7.2 mm, 17 mm < TTL < 19 mm, 1.9 < Fno < 2.1, 11 mm < IH < 11.6 mm, 105° < FOV < 120°, where f represents the effective focal length of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, and FOV represents the maximum field of view angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention: has a large aperture value, enabling the lens to achieve high-definition imaging in a relatively dark environment; has a large imaging surface, and can be matched with a larger-sized chip to achieve high-definition imaging.

[0067] In some embodiments, the eight lenses in the optical lens can all be made of plastic lenses or adopt a glass-plastic hybrid material matching structure. Preferably, the optical lens of the present invention adopts an eight-piece glass-plastic hybrid matching lens structure, which can improve the thermal stability performance. Specifically, the second lens and the third lens can be made of glass lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are all plastic lenses; adopting a glass-plastic hybrid structure can effectively reduce costs, correct aberrations, reduce volume, and provide an optical lens product with higher cost performance.

[0068] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may be spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, in the optical lens provided by the present invention, the second lens and the third lens are spherical lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may be aspherical lenses.

[0069] In various embodiments of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation: ; where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and B, C, D, E, F, G, and H are the conic coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order, respectively.

[0070] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are partially different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any change, substitution, combination, or simplification made without departing from the innovative points of the present invention shall be regarded as an equivalent substitution method and shall be included in the protection scope of the present invention.

[0071] Embodiment 1 Please refer to Figure 1 , which shows a schematic structural diagram of an optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 sequentially includes, along the optical axis from the object side to the imaging surface S19: a front group with positive optical power, a diaphragm ST, a rear group with positive optical power, and a filter G1; The front group sequentially includes, along the optical axis from the object side to the imaging surface: a first lens L1 and a second lens L2.

[0072] Among them, the first lens L1 has negative optical power, its object side surface S1 is a convex surface, and its image side surface S2 is a concave surface; The second lens L2 has positive optical power, its object side surface S3 is a convex surface, and its image side surface S4 is a convex surface.

[0073] The rear group sequentially includes, along the optical axis from the object side to the imaging surface: 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.

[0074] Among them, the third lens L3 has a positive optical power, its object side S5 is convex, and its image side S6 is concave; The fourth lens L4 has a positive optical power, its object side S7 is convex, and its image side S8 is convex; The fifth lens L5 has a negative optical power, its object side S9 is concave, and its image side S10 is concave; The sixth lens L6 has a positive optical power, its object side S11 is convex, and its image side S12 is convex; The seventh lens L7 has a negative optical power, its object side S13 is concave, and its image side S14 is convex; The eighth lens L8 has a negative optical power, its object side S15 is concave, and its image side S16 is concave near the optical axis; Both the object side S17 and the image side S18 of the filter G1 are flat; The imaging surface S19 is flat.

[0075] The second lens L2 and the third lens L3 adopt glass spherical lenses; the first lens L1, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 all adopt plastic aspherical lenses.

[0076] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0077] Table 1-1 The surface shape parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0078] Table 1-2 In this embodiment, the astigmatism curve graph, the axial aberration curve graph, and the lateral chromatic aberration curve graph of the optical lens 100 are respectively as Figure 2 , Figure 3 , Figure 4 shown.

[0079] Figure 2 shows the astigmatism curve graph of the optical lens 100 in this embodiment, which represents the astigmatism of light rays in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 100 can correct astigmatism well.

[0080] Figure 3The axial aberration curve of the optical lens 100 in this embodiment is shown, which represents the aberration on the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 100 can correct the axial aberration well.

[0081] Figure 4 The lateral chromatic aberration curve of the optical lens 100 in this embodiment is shown, which represents the chromatic aberration at different image heights on the imaging plane for each wavelength relative to the central wavelength (0.555 μm). The horizontal axis represents the lateral chromatic aberration value (unit: μm) of each wavelength relative to the central wavelength, and the vertical axis represents the normalized field of view angle. It can be seen from the figure that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 100 can correct the chromatic aberration well.

[0082] Embodiment 2 Please refer to Figure 5 , which shows the structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences are that: the object side surface S9 of the fifth lens L5 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0083] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0084] Table 2-1 The surface type parameters of the aspherical lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0085] Table 2-2 In this embodiment, the astigmatism curve, axial aberration curve, and lateral chromatic aberration curve of the optical lens 200 are respectively as shown in Figure 6 , Figure 7 , Figure 8 .

[0086] From Figure 6 it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 200 can correct the astigmatism well.

[0087] From Figure 7 it can be seen that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 200 can correct the axial aberration well.

[0088] From Figure 8It can be seen that the vertical chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0089] Example 3 Please refer to Figure 9 , which shows the structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main differences are that: the object side surface S9 of the fifth lens L5 is a convex surface; the image side surface S16 of the eighth lens L8 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0090] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0091] Table 3-1 The surface type parameters of the aspherical lenses in the optical lens 300 in Example 3 are shown in Table 3-2.

[0092] Table 3-2 In this embodiment, the astigmatism curve graph, axial aberration curve graph, and vertical chromatic aberration curve graph of the optical lens 300 are respectively as Figure 10 , Figure 11 , Figure 12 shown.

[0093] From Figure 10 it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 300 can correct astigmatism well.

[0094] From Figure 11 it can be seen that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 300 can correct axial aberration well.

[0095] From Figure 12 it can be seen that the vertical chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0096] Example 4 Please refer to Figure 13 , which shows the structural schematic diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main differences are that: the image side surface S16 of the eighth lens L8 is a convex surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0097] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0098] Table 4-1 The surface shape parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2 as follows.

[0099] Table 4-2 In this embodiment, the astigmatism curve graph, axial aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 400 are respectively as shown in Figure 14 , Figure 15 , Figure 16 .

[0100] It can be seen from Figure 14 that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 400 can correct astigmatism well.

[0101] It can be seen from Figure 15 that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 400 can correct the axial aberration well.

[0102] It can be seen from Figure 16 that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 400 can correct the chromatic aberration well.

[0103] Please refer to Table 5 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the f-number Fno, the true image height IH corresponding to the maximum field of view angle, the chief ray angle of incidence CRA at the maximum image height, the maximum field of view angle FOV, and the values corresponding to each conditional expression in each embodiment.

[0104] Table 5 In summary of the above embodiments, the optical lens provided by the present invention adopts an eight-piece glass-plastic hybrid structure. Through specific surface shape settings and reasonable optical power distribution, the structure of the optical lens is relatively compact, effectively shortening the overall length of the optical lens, which is conducive to miniaturization; it has a large f-number, enabling the lens to achieve high-definition imaging even in a relatively dark environment; at the same time, it has a large imaging surface and can match a large-size chip to achieve high-definition imaging. In addition, it can reasonably correct the overall aberration of the optical lens, has the characteristics of high pixels, and improves the imaging quality of the optical lens.

[0105] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", "some examples", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0106] The above-described embodiments merely represent several implementation manners of the present invention. The descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that, It sequentially includes, from the object side to the imaging surface along the optical axis: a front group with positive optical power and a rear group with positive optical power; The front group sequentially includes, from the object side to the imaging surface along the optical axis: a first lens with negative optical power, whose object side is convex and whose image side is concave; a second lens with positive optical power, whose object side is convex and whose image side is convex; The rear group sequentially includes, from the object side to the imaging surface along the optical axis: a third lens with positive optical power, whose object side is convex and whose image side is concave; a fourth lens with positive optical power, whose object side is convex and whose image side is convex; a fifth lens with negative optical power, whose image side is concave; a sixth lens with positive optical power, whose object side is convex and whose image side is convex; a seventh lens with negative optical power, whose object side is concave and whose image side is convex; an eighth lens with negative optical power, whose object side is concave; wherein, the combined focal length fa of the front group and the combined focal length fb of the rear group satisfy: 1.2 < fa / fb < 3.

2.

2. The optical lens according to claim 1, characterized in that The effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 60° < (f × FOV) / IH < 70°.

3. The optical lens according to claim 1, characterized in that, The overall length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.5 < TTL / f < 3; the overall length TTL of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 1.5 < TTL / IH < 1.

7.

4. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5 < f1 / f < -1.

5.

5. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.5 < f2 / f < 2; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: -1.5 < R3 / R4 < -0.

5.

6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2 < f3 / f < 6; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: 0.3 < R5 / R6 < 0.

8.

7. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.5 < f4 / f < 2; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -1.

2.

8. The optical lens according to claim 1, characterized in that The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.9 < f6 / f < 1.35; the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -8 < f7 / f < -3.

9. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -1.5 < f8 / f < -0.

9.

10. The optical lens according to claim 1, wherein The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -1.5 < f1 / f2 < -0.

8.

11. The optical lens according to claim 1, characterized in that, The distance CT12 between the first lens and the second lens on the optical axis, the central thickness CT1 of the first lens, and the central thickness CT2 of the second lens satisfy: 1.15 < CT12 / (CT1 + CT2) < 2.

12. The optical lens according to claim 1, wherein, The clear aperture DM11 of the object side surface of the first lens and the clear aperture DM82 of the image side surface of the eighth lens satisfy: 1.1 < DM11 / DM82 < 1.3.

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