Optical lens

Abstract

The application provides an optical lens, which comprises eight lenses in sequence from an object side to an imaging surface along an optical axis, and comprises a front group with positive refractive power and a rear group with positive refractive power; the front group comprises, in sequence from the object side to the imaging surface along the optical axis, a first lens with negative refractive power, a convex object side surface and a concave image side surface; a second lens with positive refractive power, a convex object side surface and a convex image side surface; the rear group comprises, in sequence from the object side to the imaging surface along the optical axis, a third lens with positive refractive power, a fourth lens with positive refractive power, a fifth lens with negative refractive power, a sixth lens with positive refractive power, a seventh lens with negative refractive power and an eighth lens with negative refractive power. The optical lens provided by the application can improve the imaging quality of the optical lens through specific surface shape matching and reasonable refractive power distribution, and has the advantages of excellent imaging quality.

Description

TECHNICAL FIELD

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

[0002] In modern video conference systems, high-quality image transmission is crucial. The video conference lenses on the current market mostly adopt fixed focus or zoom design to meet the needs of different application scenarios. However, these traditional lenses often have the problems of large size and heavy weight, which not only limit the miniaturization design of the equipment, but also increase the manufacturing cost. Therefore, it is urgent to provide an optical lens that takes into account miniaturization and excellent imaging quality and can meet the use requirements of video conferences. SUMMARY

[0003] In view of the above problems, the purpose of the present application is to provide an optical lens with the advantage of excellent imaging quality.

[0004] The present application provides an optical lens, which has a total of eight lenses and comprises, in order from the object side to the imaging surface along the optical axis, a front group with positive refractive power and a rear group with positive refractive power.

[0005] The front group comprises, in order from the object side to the imaging surface along the optical axis,

[0006] a first lens with negative refractive power, whose object side surface is convex and whose image side surface is concave;

[0007] a second lens with positive refractive power, whose object side surface is convex and whose image side surface is convex;

[0008] The rear group comprises, in order from the object side to the imaging surface along the optical axis,

[0009] a third lens with positive refractive power, whose object side surface is convex and whose image side surface is concave;

[0010] a fourth lens with positive refractive power, whose object side surface is convex and whose image side surface is convex;

[0011] a fifth lens with negative refractive power, whose image side surface is concave;

[0012] a sixth lens with positive refractive power, whose object side surface is convex and whose image side surface is convex;

[0013] a seventh lens with negative refractive power, whose object side surface is concave and whose image side surface is convex;

[0014] an eighth lens with negative refractive power, whose object side surface is concave;

[0015] 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.

[0016] Further preferably, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens and the real image height IH corresponding to the maximum field angle FOV of the optical lens satisfy: 60° < (f x FOV) / IH < 70°.

[0017] Further preferably, the total track length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.5 < TTL / f < 3; the total track length TTL of the optical lens and the real image height IH corresponding to the maximum field angle FOV of the optical lens satisfy: 1.5 < TTL / IH < 1.7.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length fl of the first lens satisfy: -2.5 < fl / f < -1.5.

[0019] Further 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 object side surface curvature radius R3 of the second lens and the image side surface curvature radius R4 of the second lens satisfy: -1.5 < R3 / R4 < -0.5.

[0020] Further 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 object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.3 < R5 / R6 < 0.8.

[0021] Further 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.

[0022] Further 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.

[0023] Further 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.

[0024] Further preferably, the focal length fl of the first lens and the focal length f2 of the second lens satisfy: -1.5 < fl / f2 < -0.8.

[0025] It is further preferred that the interval CT12 of 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.

[0026] It is further preferred that the object side light aperture DM11 of the first lens and the image side light aperture DM82 of the eighth lens satisfy: 1.1 < DM11 / DM82 < 1.3.

[0027] Compared with the prior art, the optical lens provided by the application adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages of miniaturization, large aperture, large image height, high imaging quality, etc. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the following drawings, in which:

[0029] Figure 1 Fig. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application.

[0030] Figure 2 Fig. 2 is an astigmatism curve diagram of the optical lens according to the embodiment of the present application.

[0031] Figure 3 Fig. 3 is an axial aberration curve diagram of the optical lens according to the embodiment of the present application.

[0032] Figure 4 Fig. 4 is a curve diagram of the transverse chromatic aberration of the optical lens according to the embodiment of the present application.

[0033] Figure 5 Fig. 5 is a structural schematic diagram of an optical lens according to another embodiment of the present application.

[0034] Figure 6 Fig. 6 is an astigmatism curve diagram of the optical lens according to the embodiment of the present application.

[0035] Figure 7 Fig. 7 is an axial aberration curve diagram of the optical lens according to the embodiment of the present application.

[0036] Figure 8 Fig. 8 is a curve diagram of the transverse chromatic aberration of the optical lens according to the embodiment of the present application.

[0037] Figure 9 Fig. 9 is a structural schematic diagram of an optical lens according to another embodiment of the present application.

[0038] Figure 10A plot of lateral chromatic aberration for the optical lens of Example 3 of the present application.

[0039] Figure 11 A plot of axial chromatic aberration for the optical lens of Example 3 of the present application.

[0040] Figure 12 A plot of lateral chromatic aberration for the optical lens of Example 3 of the present application.

[0041] Figure 13 A plot of lateral chromatic aberration for the optical lens of Example 4 of the present application.

[0042] Figure 14 A plot of lateral chromatic aberration for the optical lens of Example 4 of the present application.

[0043] Figure 15 A plot of axial chromatic aberration for the optical lens of Example 4 of the present application.

[0044] Figure 16 A plot of lateral chromatic aberration for the optical lens of Example 4 of the present application.

[0045] The following detailed description will further describe the present application with reference to the above drawings. DETAILED DESCRIPTION

[0046] For a better understanding of the present application, various aspects of the present application will be described in greater detail below with reference to the drawings. It is to be understood that the detailed description is merely descriptive of embodiments of the present application and that no limitation of the scope of the present application is thereby intended. Throughout the specification, like reference numbers refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] It is noted that, in this specification, the expressions first, second, third, etc. are merely used to distinguish one feature from another feature, and do not indicate any limitation of the features. Thus, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0048] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0049] In the present disclosure, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0050] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when describing the embodiments of the present application, the word "may" means "one or more embodiments of the present application". Furthermore, the word "exemplary" is intended to mean "an example or illustration".

[0051] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that the terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0052] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0053] The optical lens provided by the embodiments of the present application comprises eight lenses, which are sequentially arranged along the optical axis from the object side to the image plane and comprise a front group with positive refractive power and a rear group with positive refractive power.

[0054] Specifically, the front group sequentially comprises a first lens and a second lens along the optical axis from the object side to the image plane. The first lens can have negative refractive power, and the object side surface thereof is convex, and the image side surface thereof is concave. The second lens can have positive refractive power, and the object side surface thereof is convex, and the image side surface thereof is convex.

[0055] The rear group includes, in order from the object side to the imaging surface along the optical axis, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The third lens can have positive refractive power, the object side surface of which is convex, and the image side surface of which is concave. The fourth lens can have positive refractive power, the object side surface of which is convex, and the image side surface of which is convex. The fifth lens can have negative refractive power, the object side surface of which can be concave or convex, and the image side surface of which is concave. The sixth lens can have positive refractive power, the object side surface of which is convex, and the image side surface of which is convex. The seventh lens can have negative refractive power, the object side surface of which is concave, and the image side surface of which is convex. The eighth lens can have negative refractive power, the object side surface of which is concave, and the image side surface of which can be concave or convex.

[0056] In some embodiments, the optical lens can further include a diaphragm, which can 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 light entering to change the brightness of the imaging. At the same time, the diaphragm is arranged between the front group and the rear group to limit the light beam, which can reduce the generation of ghost images of the optical lens, is conducive to converging the light entering the optical system, reduces the rear aperture of the optical lens, and the arrangement of the diaphragm also makes the optical lens have a larger aperture, improves the light entering amount of the lens, and enables the lens to also have high-definition imaging in a dim environment.

[0057] In some embodiments, the optical lens can further include a filter, which is arranged between the eighth lens and the imaging surface. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0058] 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. By reasonably setting the focal length relationship of the diaphragm front and rear lens groups, the above condition is met, which is conducive to the incidence of light on one hand, enabling the light entering the system at the front to smoothly enter the rear optical system, making the overall light path more gentle, and is conducive to optimizing aberration and improving the overall resolution of the lens on the other hand.

[0059] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the real image height IH corresponding to the maximum field of view FOV of the optical lens satisfy: 60° < (f x FOV) / IH < 70°. By meeting the above condition, the demand for large-angle imaging and high-definition imaging can be effectively balanced, and the adaptability of the optical lens in different application scenarios can be improved.

[0060] In some embodiments, 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. By meeting the above condition, the length of the lens can be effectively limited, which is conducive to the miniaturization of the optical lens.

[0061] In some embodiments, the total track length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.5 < TTL / IH < 1.7. Satisfying the above condition, the miniaturization of the lens can be better achieved, and meanwhile, the lens has a larger image surface under the condition of the same total length, which can match a larger imaging chip to realize high-definition imaging.

[0062] 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. Satisfying the above condition, the first lens can have a larger negative refractive power, and can receive as much light as possible into the system, which is beneficial to increasing the field angle of the optical lens.

[0063] 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. Satisfying the above condition, the second lens is set to have a larger positive refractive power, which can effectively converge the light entering the system, improve the light collection ability of the edge field of view, and improve the overall imaging quality.

[0064] In some embodiments, 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. Satisfying the above condition, the double convex surface of the second lens is reasonably set, which is beneficial to receiving large-angle incident light and controlling the incident light to enter the optical system relatively gently, thereby reducing the tolerance sensitivity of the optical system.

[0065] 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; and the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.5 < f4 / f < 2. Satisfying the above conditions, the positive refractive power of the third and fourth lenses is set, which can effectively converge the front-end incident light, is beneficial to correcting the aberration caused by the front-end lens and the distortion of the edge field of view, makes the lens have smaller distortion, and can provide high-definition imaging effect.

[0066] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 0.3 < R5 / R6 < 0.8. Satisfying the above condition is beneficial to better realizing the convergence of light, shortening the distance of light reaching the next lens, and is beneficial to reducing the total length of the optical lens.

[0067] 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. Satisfying the above condition can make the fifth lens have a larger negative refractive power, which can make the light diverge appropriately, is beneficial to increasing the imaging area of the optical lens, and improves the imaging quality of the optical lens.

[0068] 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 radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature 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 appropriate positive refractive power and suitable surface shape, which is beneficial to smooth transition of light rays and balances the spherical aberration and field curvature of the fifth lens, thereby improving the imaging quality of the optical lens.

[0069] 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. By satisfying the above conditions, the edge field of view light rays can be effectively diverged by reasonably setting the focal length and suitable surface shape of the seventh lens, and the exit angle of the edge field of view light rays is reduced by the bending of the edge region of the eighth lens, thereby improving the relative luminance of the edge field of view.

[0070] 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. By satisfying the above conditions, the incident light rays can be diverged to a greater extent by setting the eighth lens to have a larger negative refractive power, so that the peripheral light rays and the central light rays are turned upward to reach a higher imaging position, thereby better achieving large target surface imaging of the lens and improving the imaging quality.

[0071] 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. By satisfying the above conditions, the wide field angle object plane light can be converged into the lens by reasonably allocating the focal length relationship of the first and second lenses, which is beneficial to achieve the balance of large field of view and large aperture of the optical lens.

[0072] In some embodiments, the distance CT12 of 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. By satisfying the above conditions, the incident light rays can be smoothly transitioned by setting a larger air gap between the first and second lenses, which is also beneficial to correct the aberration caused by the first lens and improve the imaging quality of the optical lens.

[0073] In some embodiments, the object-side aperture of the first lens DM11 and the image-side aperture of the eighth lens DM82 satisfy 1.1<DM11 / DM82<1.3. Satisfying the above condition, the lens has a larger entrance aperture, and the area of light entering the imaging surface is increased while ensuring as much light as possible to enter the system, which is conducive to achieving a balance between a large image surface and a large aperture of the lens.

[0074] In some embodiments, the real image height IH corresponding to the maximum field of view angle of the optical lens and the aperture value Fno of the optical lens satisfy 5.3mm<IH / Fno<6mm. Satisfying the above condition, the lens has a larger aperture while having a larger imaging target surface, ensuring that the lens has a larger light flux in a darker environment, thereby improving the picture quality of the lens in different environments.

[0075] 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. Satisfying the above condition, the front group before the stop has appropriate positive refractive power, which can converge the wide field of view angle of the object surface into the lens, better correct the edge distortion of the lens, and not produce larger aberrations.

[0076] 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. Satisfying the above condition, the rear group after the stop has larger positive refractive power, which is conducive to balancing the distortion and astigmatism generated by the front lens of the optical lens and improving the imaging quality of the optical lens.

[0077] 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. Satisfying the above condition, by reasonably setting the focal length relationship of the seventh and eighth lenses, the light of the edge field of view can be effectively diverged, and the exit angle of the light of the edge field of view is reduced by the curvature of the edge region of the eighth lens, thereby improving the relative luminance of the edge field of view.

[0078] In some embodiments, the optical lens satisfies the conditions: 6.2mm<f<7.2mm, 17mm<TTL<19mm, 1.9<Fno<2.1, 11mm<IH<11.6mm, 105°<FOV<120°, wherein f represents the effective focal length of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the real 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. Satisfying the above conditions, the optical lens provided by the embodiments of the present application has a larger aperture value, so that the lens can realize high-definition imaging in a darker environment, and has a larger imaging surface, which can match a larger size chip to realize high-definition imaging.

[0079] In some embodiments, the eight lenses in the optical lens can all adopt plastic lenses or adopt a glass-plastic hybrid material collocation structure. Preferably, the optical lens of the present application adopts an eight-lens glass-plastic hybrid collocation structure, which can improve the thermal stability. Specifically, the second lens and the third lens can adopt glass lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can all be plastic lenses. The glass-plastic hybrid structure can effectively reduce the cost, correct the aberration, reduce the size, and provide a higher cost-effective optical lens product.

[0080] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt spherical lenses or aspherical lenses. The aspherical structure can effectively reduce the aberration of the optical system compared to the spherical structure, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization. More specifically, the second lens and the third lens in the optical lens of the present application can adopt spherical lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt aspherical lenses.

[0081] In various embodiments of the present application, when the lenses adopt aspherical lenses, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0082] ;

[0083] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients, respectively.

[0084] The present application will be further described in the following embodiments. In various embodiments, the thickness, curvature radius, and material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present application, but the embodiments of the present application are not limited to the following embodiments, and any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present application should be considered as equivalent replacement methods, and are included in the protection scope of the present application.

[0085] Embodiment 1

[0086] Please refer to Figure 1Fig. 1 shows a structural schematic diagram of an optical lens 100 provided in Embodiment 1 of the present application, which comprises, along an optical axis from an object side to an imaging surface S19, a front group with positive refractive power, a stop ST, a rear group with positive refractive power, and a filter G1;

[0087] The front group comprises, along the optical axis from the object side to the imaging surface, a first lens L1 and a second lens L2.

[0088] The first lens L1 has negative refractive power, and its object side surface S1 is a convex surface and its image side surface S2 is a concave surface.

[0089] The second lens L2 has positive refractive power, and its object side surface S3 is a convex surface and its image side surface S4 is a convex surface.

[0090] The rear group comprises, 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.

[0091] The third lens L3 has positive refractive power, and its object side surface S5 is a convex surface and its image side surface S6 is a concave surface.

[0092] The fourth lens L4 has positive refractive power, and its object side surface S7 is a convex surface and its image side surface S8 is a convex surface.

[0093] The fifth lens L5 has negative refractive power, and its object side surface S9 is a concave surface and its image side surface S10 is a concave surface.

[0094] The sixth lens L6 has positive refractive power, and its object side surface S11 is a convex surface and its image side surface S12 is a convex surface.

[0095] The seventh lens L7 has negative refractive power, and its object side surface S13 is a concave surface and its image side surface S14 is a convex surface.

[0096] The eighth lens L8 has negative refractive power, and its object side surface S15 is a concave surface and its image side surface S16 is a concave surface near the optical axis.

[0097] The object side surface S17 and the image side surface S18 of the filter G1 are both flat surfaces.

[0098] The imaging surface S19 is a flat surface.

[0099] The second lens L2 and the third lens L3 are glass spherical lenses, and 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 are plastic aspherical lenses.

[0100] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0101] Table 1-1

[0102]

[0103] The surface shape parameters of the aspherical lens of the optical lens 100 in the embodiment 1 are shown in Table 1-2.

[0104] Table 1-2

[0105]

[0106] In the embodiment, the astigmatism curve, the axial aberration curve and the lateral chromatic aberration curve of the optical lens 100 are shown in Figure 2 、 Figure 3 、 Figure 4 respectively.

[0107] Figure 2 The astigmatism curve of the optical lens 100 in the embodiment is shown, which represents the astigmatism of the light rays on the sagittal image surface and the tangential image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the astigmatism of the sagittal image surface and the tangential image surface is controlled within ±0.05mm, which shows that the optical lens 100 can better correct the astigmatism.

[0108] Figure 3 The axial aberration curve of the optical lens 100 in the embodiment is shown, which represents the aberration of the optical axis at the imaging surface at 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 ±0.02mm, which shows that the optical lens 100 can better correct the axial aberration.

[0109] Figure 4 The lateral chromatic aberration curve of the optical lens 100 in the embodiment is shown, which represents the chromatic aberration of different image heights on the imaging surface at each wavelength relative to the central wavelength (0.555μm), 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 angle. It can be seen from the figure that the lateral chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, which shows that the optical lens 100 can better correct the chromatic aberration.

[0110] Embodiment 2

[0111] Please refer to Figure 5 , which is a structural schematic diagram of the optical lens 200 provided in the embodiment 2 of the present application. Compared with the embodiment 1, the main difference is that the object side S9 of the fifth lens L5 is a convex surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0112] The related parameters of each lens in the optical lens 200 in the embodiment 2 are shown in Table 2-1.

[0113] Table 2-1

[0114]

[0115] The surface shape parameters of the aspherical lenses of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0116] Table 2-2

[0117]

[0118] In this embodiment, the astigmatism curve, the axial aberration curve and the transverse chromatic aberration curve of the optical lens 200 are shown in Figure 6 , Figure 7 , Figure 8 respectively.

[0119] As can be seen from Figure 6 , the astigmatism of the sagittal image surface and the tangential image surface is controlled within ±0.05mm, which shows that the optical lens 200 can correct the astigmatism well.

[0120] As can be seen from Figure 7 , the shift of the axial aberration is controlled within ±0.02mm, which shows that the optical lens 200 can correct the axial aberration well.

[0121] As can be seen from Figure 8 , the transverse chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, which shows that the optical lens 200 can correct the chromatic aberration well.

[0122] Embodiment 3

[0123] Please refer to Figure 9 , which is a structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present application. Compared with Embodiment 1, the main difference is that the object side S9 of the fifth lens L5 is a convex surface; the image side S16 of the eighth lens L8 is a convex surface; the optical parameters such as the curvature radius and the lens thickness of each lens surface are different.

[0124] The related parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0125] Table 3-1

[0126]

[0127] The surface shape parameters of the aspherical lenses of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0128] Table 3-2

[0129]

[0130] In this embodiment, the astigmatism curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens 300 are respectively as follows: Figure 10 , Figure 11 , Figure 12 As shown.

[0131] from Figure 10 As can be seen, the astigmatism of the meridional and sagittal image planes is controlled within ±0.05mm, indicating that the optical lens 300 can effectively correct astigmatism.

[0132] from Figure 11 As can be seen, the axial aberration offset is controlled within ±0.03mm, indicating that the optical lens 300 can correct axial aberration well.

[0133] from Figure 12 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0134] Example 4

[0135] Please see Figure 13 The figure shows a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that the image side surface S16 of the eighth lens L8 is a convex surface; the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0136] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0137] Table 4-1

[0138]

[0139] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0140] Table 4-2

[0141]

[0142] In this embodiment, the astigmatism curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens 400 are respectively as follows: Figure 14 , Figure 15 , Figure 16 As shown.

[0143] from Figure 14 As can be seen, the astigmatism of the meridional and sagittal image planes is controlled within ±0.05mm, indicating that the optical lens 400 can effectively correct astigmatism.

[0144] From Figure 15 It can be seen from the above table that the axial aberration is controlled within ±0.02mm, which indicates that the optical lens 400 can correct the axial aberration well.

[0145] From Figure 16 It can be seen from the above table that the axial aberration is controlled within ±0.02mm, which indicates that the optical lens 400 can correct the axial aberration well.

[0146] Please refer to Table 5 for the optical characteristics corresponding to the above-mentioned embodiments, including the effective focal length f, the total optical length TTL, the aperture value Fno, the real 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 of the optical lens, and the numerical value corresponding to each conditional expression in each embodiment.

[0147] Table 5

[0148]

[0149] In summary of the above embodiments, the optical lens provided by the present application adopts an eight-piece glass-plastic hybrid structure, and through specific surface shape setting and reasonable power distribution, the structure of the optical lens is relatively compact, the overall length of the optical lens is effectively shortened, which is conducive to miniaturization; has a large aperture value, so that the lens can also realize high-definition imaging in a dark environment; at the same time, has a large imaging surface, which can match a large-size chip to realize high-definition imaging. In addition, the overall aberration of the optical lens can be reasonably corrected, has the characteristics of high pixels, and improves the imaging quality of the optical lens.

[0150] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", "some examples" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does 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.

[0151] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. An optical lens comprising eight lenses, characterized in that, It includes, in order 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 includes, in order 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 includes, in order 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; 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; The overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.5 < TTL / IH < 1.

7.

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

3. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 5.3mm < IH / Fno < 6mm.

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, characterized in that, 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, characterized in that, 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, characterized in that, 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 center thickness CT1 of the first lens, and the center thickness CT2 of the second lens satisfy: 1.15 <CT12 / (CT1+CT2)<2。 12. The optical lens according to claim 1, characterized in that, The object-side aperture DM11 of the first lens and the image-side aperture DM82 of the eighth lens satisfy: 1.1 <DM11 / DM82<1.3。

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