Optical lens

Abstract

The present invention provides an optical lens, which sequentially includes, along the optical axis from the object side to the imaging surface: a first lens with a negative optical power, whose object side is convex and image side is concave; a second lens with a negative optical power, whose object side is convex and image side is concave; a third lens with a positive optical power, whose object side is convex and image side is flat; a fourth lens with a positive optical power, whose object side is convex and image side is convex; a fifth lens with a negative optical power, whose image side is concave; a sixth lens with a positive optical power, whose object side is concave and image side is convex; a seventh lens with a negative optical power, whose object side is convex near the optical axis and image side is concave near the optical axis; an eighth lens with a negative optical power, whose object side is convex near the optical axis and image side is concave near the optical axis. The optical lens provided by the present invention can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens.

Description

Technical Field

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

[0002] With the continuous upgrading of drones, consumers have higher and higher requirements for drone functions. Ultra-high pixel, large aperture, and wide-angle shooting have become the main development trends of drones. In order to pursue high-quality imaging, currently mainstream drones mostly use all-glass lenses, and the number of lenses has been upgraded from 5-6 pieces to 7-8 pieces to correct the optical path. However, restricted by glass lenses, it is difficult to reduce the weight and volume of glass lenses, and the all-glass lens has encountered a bottleneck period. Since plastic lenses are lighter and more malleable, lenses using plastic lenses can be effectively thinned. At the same time, combining the advantages of plastic lenses, large field-of-view shooting can be achieved while ensuring the light input and imaging clarity of the optical lens, which is expected to be applied in high-end drones and is the development trend of future drone lenses. However, how to better achieve large field-of-view, large target surface imaging, and high pixel performance of the lens is still an urgent problem to be solved. Summary of the Invention

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

[0004] The technical solution adopted by the present invention is as follows:

[0005] An optical lens is composed of eight lenses, which sequentially include, along the optical axis from the object side to the imaging surface:

[0006] A first lens with negative optical power, whose object side is convex and whose image side is concave;

[0007] A second lens with negative optical power, whose object side is convex and whose image side is concave;

[0008] A third lens with positive optical power, whose object side is convex and whose image side is flat;

[0009] A fourth lens with positive optical power, whose object side is convex and whose image side is convex;

[0010] A fifth lens with negative optical power, whose image side is concave;

[0011] A sixth lens with positive optical power, whose object side is concave and whose image side is convex;

[0012] A seventh lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; [[ID=4,2]]

[0013] An eighth lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis;

[0014] Among them, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.7 < TTL / f < 3.

[0015] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.1 < f1 / f < -1.3.

[0016] Further preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.8 < IH / EPD < 8.5.

[0017] Further preferably, the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.6 < f / EPD < 2.7.

[0018] Further preferably, the image-side curvature radius R14 of the seventh lens and the focal length f7 of the seventh lens satisfy: -0.35 < R14 / f7 < -0.25.

[0019] Further preferably, the effective focal length f of the optical lens, the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.35 < f / (R1 - R2) < 0.52.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.65 < f7 / f < -1.5.

[0021] Further preferably, the image-side curvature radius R12 of the sixth lens and the image-side curvature radius R14 of the seventh lens satisfy: -1.2 < R12 / R14 < -1.

[0022] Further preferably, the center thickness CT1 of the first lens, the edge thickness ET1 of the first lens, the center thickness CT2 of the second lens and the edge thickness ET2 of the second lens satisfy: 0.3 < (CT1 / ET1) / (CT2 / ET2) < 0.6.

[0023] Further preferably, the object-side end clear aperture semi-diameter CSD11 of the first lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.25 < CSD11 / IH < 0.3.

[0024] 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 aberration, and enhance the imaging quality of the optical lens, enabling the lens to have one or more advantages such as a large field of view angle, miniaturization, a large target surface, and high pixels. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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:

[0026] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 2 is a field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 is a distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 is a longitudinal chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 is a lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 7 is a field curvature curve graph of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 is a distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 is a longitudinal chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 10 is a lateral chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 11 is a schematic structural diagram of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 12 is a field curvature curve graph of the optical lens in Embodiment 3 of the present invention.

[0038] Figure 13 is a distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0039] Figure 14 This is the longitudinal chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 15 This is the lateral chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0041] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0042] 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.

[0043] 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 features. 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.

[0044] In the drawings, for the sake of convenience of illustration, the thickness, size, and shape of the lens have been slightly exaggerated. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0045] In this article, 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.

[0046] It should also be understood that the terms "comprising", "comprises", "having", "includes" and / or "including", 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. In addition, 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 an individual element in the list. In addition, 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.

[0047] Unless otherwise defined, all terms used herein (including technical and scientific terms) 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.

[0048] 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 drawings and in combination with the embodiments.

[0049] The optical lens provided by the embodiment of the present invention is composed of eight lenses, which are, in order from the object side to the imaging surface along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0050] In some embodiments, the first lens may have a negative focal power, its object side is convex, and its image side is concave. The second lens may have a negative focal power, its object side is convex, and its image side is concave. The third lens may have a positive focal power, its object side is convex, and its image side is flat. The fourth lens may have a positive focal power, its object side is convex, and its image side is convex. The fifth lens may have a negative focal power, its object side may be concave or convex, and its image side is concave. The sixth lens may have a positive focal power, its object side is concave, and its image side is convex. The seventh lens may have a negative focal power, its object side is convex near the optical axis, and its image side is concave near the optical axis. The eighth lens may have a negative focal power, its object side is convex near the optical axis, and its image side is concave near the optical axis.

[0051] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the third lens and the fourth lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image. When the diaphragm is located between the third lens and the fourth lens, it is convenient for correcting the diaphragm aberration.

[0052] In some embodiments, the optical lens may further include a filter, which may be 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.

[0053] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.7 < TTL / f < 3. Meeting the above conditions can not only achieve the characteristics of a large target surface and a large viewing angle of the lens, so as to meet the local shooting requirements and be able to match a larger-size chip, but also achieve high-pixel imaging of the lens, improving the lens resolution and the receiving field of view.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.1 < f1 / f < -1.3. Meeting the above conditions, the lens closest to the object side is set as a negative lens, providing negative bending power for the lens, which is beneficial for the lens to obtain more object space information, that is, beneficial for increasing the field of view angle of the lens; by designing and controlling the ratio of f1 and f, a reasonable configuration is obtained, enabling the lens to capture the light beam incident at a large angle, expanding the field of view angle range of the lens, and achieving the design of low sensitivity and miniaturization of the lens; of course, a reasonable configuration of the effective focal length of the first lens is used to effectively balance the chromatic aberration of the lens and reduce the performance sensitivity of the lens.

[0055] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.8 < IH / EPD < 8.5. Meeting the above conditions is beneficial for achieving large target surface imaging and improving the image plane brightness of the lens. When the lens exceeds the upper limit of the above relationship, the entrance pupil diameter of the lens is smaller, reducing the width of the light beam incident on the lens and being unfavorable for improving the image plane brightness; when the lens is lower than the lower limit of the above relationship, the image plane area of the optical lens is smaller, reducing the field of view range of the lens and being unfavorable for matching with the chip, and prone to vignetting.

[0056] In some embodiments, the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.6 < f / EPD < 2.7. Meeting the above conditions, by controlling the ratio of the total effective focal length to the entrance pupil diameter, the lens has the advantage of a large aperture, thereby increasing the light flux of the lens and enhancing the imaging effect of the lens in a dark environment.

[0057] In some embodiments, the image-side curvature radius R14 of the seventh lens and the focal length f7 of the seventh lens satisfy: -0.35 < R14 / f7 < -0.25. Meeting the above conditions, controlling the ratio of the image-side curvature radius of the seventh lens to the effective focal length of the seventh lens is beneficial for correcting marginal aberration and slowly raising the marginal rays, which is beneficial for achieving a large target surface.

[0058] In some embodiments, the effective focal length f of the optical lens, the curvature radius R1 of the object side surface of the first lens, and the curvature radius R2 of the image side surface of the first lens satisfy: 0.35 < f / (R1 - R2) < 0.52. By satisfying the above conditions, the shape of the first lens can be effectively controlled, the contribution of the first lens to the high-order aberration can be reduced, and the lens can have better resolution.

[0059] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.65 < f7 / f < -1.5. By satisfying the above conditions, the optical power of the seventh lens is reasonably distributed, so that the light can be smoothly elevated upward and enter the image plane, which is beneficial to achieving a large target surface, and at the same time is beneficial to correcting the residual aberration of the lens and further improving the imaging quality.

[0060] In some embodiments, the curvature radius R12 of the image side surface of the sixth lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: -1.2 < R12 / R14 < -1. By satisfying the above conditions, by reasonably controlling the ratio of the curvature radius of the image side surface of the sixth lens to the curvature radius of the image side surface of the seventh lens, the assembly step difference between the sixth lens and the seventh lens can be effectively controlled within a reasonable range, which is convenient for processing and assembly. At the same time, the aberration of the lens can be more easily balanced, and the imaging quality of the lens can be improved.

[0061] In some embodiments, the central thickness CT1 of the first lens, the edge thickness ET1 of the first lens, the central thickness CT2 of the second lens, and the edge thickness ET2 of the second lens satisfy: 0.3 < (CT1 / ET1) / (CT2 / ET2) < 0.6. By satisfying the above conditions, by controlling the central thickness and edge thickness of the first lens, and the central thickness and edge thickness of the second lens, the thickness ratio of the first lens and the second lens can be reasonably controlled, so as to optimize the surface curvature freedom of the first lens and the second lens, which is beneficial to the effective convergence of large-angle incident light, and the light passing through the first lens and the second lens has a small deflection angle, thereby reducing the generation of stray light in the lens, and further ensuring excellent imaging performance; at the same time, the reasonable surface shape change can optimize the processing technology of the lens and reduce the design and assembly sensitivity of the first lens and the second lens.

[0062] In some embodiments, the clear aperture semi-diameter CSD11 of the object side end of the first lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.25 < CSD11 / IH < 0.3. Meeting the above conditions, since the first lens mainly converges light rays, the larger the aperture of the first lens, the better the light collection effect; however, a larger aperture will increase the overall size of the lens. Therefore, it is possible to ensure that the aperture of the first lens and the image height of the lens are within an appropriate range, thereby controlling the aperture of the first lens so as to balance the illuminance, field of view angle, and size.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -3.3 < f5 / f < -2.2. Meeting the above conditions can make the fifth lens have an appropriate negative optical power, which is beneficial to balancing various aberrations generated by the lens, improving the imaging quality of the lens, and at the same time can increase the imaging area of the lens and improve the imaging quality.

[0064] In some embodiments, the central thickness CT1 of the first lens and the edge thickness ET1 of the first lens satisfy: 0.4 < CT1 / ET1 < 0.7. Meeting the above conditions, by controlling the ratio of the central thickness of the first lens on the optical axis to the edge thickness of the first lens, it is beneficial to control the thickness distribution of the first lens, and make the first lens easy to process and form. In addition, it is beneficial to correct the spherical aberration of the lens and improve the imaging quality.

[0065] In some embodiments, the effective focal length f of the optical lens and the image side curvature radius R14 of the seventh lens satisfy: 0.4 < R14 / f < 0.55. Meeting the above conditions can correct the spherical aberration of the lens and improve the imaging quality; and the surface shape of the image side of the seventh lens changes from the optical axis to the edge, such as from a concave surface to a convex surface and then to a concave surface. This kind of surface shape change can correct the chromatic aberration and ghost image problems in the off-axis field of view, improve the imaging quality of the edge field of view, and converge the angle of the edge field of view incident on the imaging surface and the edge field of view aberration, ensuring the matching with the photosensitive element to present a good peripheral field of view image.

[0066] In some embodiments, the clear aperture semi-diameter CSD11 of the object side end of the first lens and the sagittal height SAGX11 of the clear aperture semi-diameter of the object side end of the first lens satisfy: 4.8 < CSD11 / SAGX11 < 5.2. Meeting the above conditions can avoid the surface shape of the object side of the first lens from being too curved, which is beneficial to the incidence of large-angle light rays into the lens, thereby beneficial to expanding the field of view angle of the lens and improving the imaging quality of the optical lens. At the same time, it is also beneficial to reduce the processing difficulty of the first lens and avoid the situation of uneven coating caused by the too curved surface shape of the object side of the first lens; in addition, it can also avoid the surface shape of the object side of the first lens from being too flat, which is beneficial to reducing the risk of generating ghost images.

[0067] In some embodiments, the central thickness CT8 of the eighth lens and the clear aperture semi-diameter CSD82 on the image side end of the eighth lens satisfy: 0.1 < CT8 / CSD82 < 0.25. Meeting the above conditions can reasonably distribute the ratio of the central thickness of the eighth lens to the clear aperture semi-diameter. The surface shape of the eighth lens will not be too curved or too flat, and the thickness of the eighth lens will not be too thin or too thick, which is beneficial to improving the molding processability of the eighth lens.

[0068] In some embodiments, the optical lens satisfies the conditional formula: 3.5mm < f < 4.5mm, 130° < FOV < 140°, 11mm < TTL < 12mm, 2.5 < Fno < 2.8, 12mm < IH < 12.5mm; where f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, and IH represents the true image height corresponding to 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 at least the characteristics of miniaturization, large field of view angle, and large target surface, etc.

[0069] In some embodiments, the eight lenses in the optical lens can all be made of plastic lenses or adopt a structure with a combination of glass and plastic materials. Preferably, the optical lens of the present invention adopts a lens structure with eight pieces of glass and plastic hybrid matching, which can enable the optical lens to better match a large target surface chip to achieve high-definition imaging, and at the same time can also achieve a reasonable balance of miniaturization, large image surface, and large field of view angle of the optical lens. Specifically, the third lens can be made of a glass lens, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are all plastic lenses; the third lens is made of glass material, which can improve the thermal stability of the optical lens, reduce aberration and distortion, and make the imaging of the optical lens clearer and sharper.

[0070] 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. 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, the third lens of the present invention adopts a spherical lens, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can all adopt aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens.

[0071] In each embodiment of the present invention, when the lens adopts an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0072] ;

[0073] Wherein, z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, F, G, H are the conic coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders respectively.

[0074] The present invention will be further described below with reference to multiple embodiments. 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 tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent substitution methods and are included in the protection scope of the present invention.

[0075] Embodiment 1

[0076] 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 sequentially includes, along the optical axis from the object side to the imaging surface: a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0077] Wherein, the first lens L1 has a negative optical power, its object side surface S1 is a convex surface, and its image side surface S2 is a concave surface;

[0078] The second lens L2 has a negative optical power, its object side surface S3 is a convex surface, and its image side surface S4 is a concave surface;

[0079] The third lens L3 has a positive optical power, its object side surface S5 is a convex surface, and its image side surface S6 is a flat surface;

[0080] The fourth lens L4 has a positive optical power, its object side surface S7 is a convex surface, and its image side surface S8 is a convex surface;

[0081] The fifth lens L5 has a negative optical power, its object side surface S9 is a convex surface near the optical axis, and its image side surface S10 is a concave surface;

[0082] The sixth lens L6 has a positive optical power, its object side surface S11 is a concave surface, and its image side surface S12 is a convex surface;

[0083] The seventh lens L7 has a negative optical power, its object side surface S13 is a convex surface near the optical axis, and its image side surface S14 is a concave surface near the optical axis;

[0084] The eighth lens L8 has a negative optical power. Its object side S15 is convex near the optical axis, and its image side S16 is concave near the optical axis.

[0085] Both the object side S17 and the image side S18 of the filter G1 are flat surfaces.

[0086] The imaging surface S19 is a flat surface.

[0087] The third lens L3 is a glass spherical lens, and the first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are all plastic aspherical lenses.

[0088] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0089] Table 1-1

[0090]

[0091] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0092] Table 1-2

[0093]

[0094] In this embodiment, the field curvature curve graph, distortion curve graph, longitudinal chromatic aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 100 are respectively as Figure 2 , Figure 3 , Figure 4 , Figure 5 shown.

[0095] Figure 2 shows the field curvature curve graph of the optical lens 100 in this embodiment, which represents the field curvature 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 field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 100 can correct the field curvature well.

[0096] Figure 3 shows the distortion curve graph of the optical lens 100 in this embodiment, which represents the distortion at different field angles on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the distortion value is controlled within -35% to 0, indicating that the optical lens 100 can correct the distortion well.

[0097] Figure 4The longitudinal chromatic aberration curve graph of the optical lens 100 in this embodiment is shown, which represents the chromatic aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the longitudinal chromatic 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 longitudinal chromatic aberration is controlled within ±0.03 mm, indicating that the optical lens 100 can correct the longitudinal chromatic aberration well.

[0098] Figure 5 The lateral chromatic aberration curve graph of the optical lens 100 in this embodiment is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the lateral chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), 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 ±4 μm, indicating that the optical lens 100 can correct the lateral chromatic aberration well.

[0099] Embodiment 2

[0100] Please refer to Figure 6 , 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 difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0101] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0102] Table 2-1

[0103]

[0104] The surface type parameters of the aspherical lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0105] Table 2-2

[0106]

[0107] In this embodiment, the field curvature curve graph, distortion curve graph, longitudinal chromatic aberration curve graph, and lateral chromatic aberration curve graph of the optical lens 200 are respectively as shown in Figure 7 , Figure 8 , Figure 9 , Figure 10 .

[0108] From Figure 7 it can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 200 can correct the field curvature well.

[0109] From Figure 8It can be seen that the distortion value is controlled within -40% to 0, indicating that the optical lens 200 can correct distortion well.

[0110] From Figure 9 it can be seen that the offset of the longitudinal chromatic aberration is controlled within ±0.03 mm, indicating that the optical lens 200 can correct the longitudinal chromatic aberration well.

[0111] From Figure 10 it can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±3 μm, indicating that the optical lens 200 can correct the lateral chromatic aberration well.

[0112] Embodiment 3

[0113] Please refer to Figure 11 , 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 difference is that: the object side surface S9 of the fifth lens L5 is a concave surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0114] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3-1.

[0115] Table 3-1

[0116]

[0117] The surface type parameters of the aspherical lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0118] Table 3-2

[0119]

[0120] In this embodiment, the field curvature curve diagram, distortion curve diagram, longitudinal chromatic aberration curve diagram, and lateral chromatic aberration curve diagram of the optical lens 300 are respectively as Figure 12 , Figure 13 , Figure 14 , Figure 15 shown.

[0121] From Figure 12 it can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 300 can correct the field curvature well.

[0122] From Figure 13 it can be seen that the distortion value is controlled within -40% to 0, indicating that the optical lens 300 can correct the distortion well.

[0123] From Figure 14It can be seen that the offset of the longitudinal chromatic aberration is controlled within ±0.02 mm, indicating that the optical lens 300 can correct the longitudinal chromatic aberration well.

[0124] As can be seen from Figure 15 It can be seen that the lateral chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±3 μm, indicating that the optical lens 300 can correct the lateral chromatic aberration well.

[0125] Please refer to Table 4 for the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value 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 formula in each embodiment.

[0126] Table 4

[0127]

[0128] Based on the above embodiments, the optical lens provided by the present invention has at least the following advantages:

[0129] (1) By setting a specific surface shape and reasonably distributing the optical power, the overall length of the optical lens can be effectively shortened, which is beneficial to better realizing the miniaturization of the optical lens; at the same time, it has a large field of view angle, improving the lens resolution and the receiving field of view range.

[0130] (2) The large target surface characteristic of the lens is realized, which can match an imaging chip with a larger target surface to achieve high-definition imaging. Moreover, with the increase of the target surface, the pixel distribution can be sparser (i.e., the pixel size is larger), and even in a darker environment, noise can be effectively reduced, the dynamic range will be wider, and more details can be retained in the dark part, so as to present a clearer shooting effect; at the same time, it can reasonably correct the overall aberration of the optical lens, making the optical lens have high pixels and improving the imaging quality of the optical lens.

[0131] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "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.

[0132] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for 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 modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. An optical lens, which is composed of eight lenses, is characterized in that, From the object side to the imaging surface along the optical axis, it sequentially includes: A first lens with a negative optical power, whose object side surface is convex and whose image side surface is concave; A second lens with a negative optical power, whose object side surface is convex and whose image side surface is concave; A third lens with a positive optical power, whose object side surface is convex and whose image side surface is flat; A fourth lens with a positive optical power, whose object side surface is convex and whose image side surface is convex; A fifth lens with a negative optical power, whose image side surface is concave; A sixth lens with a positive optical power, whose object side surface is concave and whose image side surface is convex; A seventh lens with a negative optical power, whose object side surface is convex near the optical axis and whose image side surface is concave near the optical axis; An eighth lens with a negative optical power, whose object side surface is convex near the optical axis and whose image side surface is concave near the optical axis; Wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.7 < TTL / f < 3, 11mm < TTL < 12mm, 3.5mm < f < 4.5mm; The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.65 < f7 / f < -1.

5.

2. The optical lens according to claim 1, wherein The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.1 < f1 / f < -1.

3.

3. The optical lens according to claim 1, wherein, The true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.8 < IH / EPD < 8.

5.

4. The optical lens according to claim 1, wherein, The effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.6 < f / EPD < 2.

7.

5. The optical lens according to claim 1, wherein The image side curvature radius R14 of the seventh lens and the focal length f7 of the seventh lens satisfy: -0.35 < R14 / f7 < -0.

25.

6. The optical lens according to claim 1, wherein The effective focal length f of the optical lens, the object side curvature radius R1 of the first lens and the image side curvature radius R2 of the first lens satisfy: 0.35 < f / (R1 - R2) < 0.

52.

7. The optical lens according to claim 1, characterized in that The image side curvature radius R12 of the sixth lens and the image side curvature radius R14 of the seventh lens satisfy: -1.2 < R12 / R14 < -1.

8. The optical lens according to claim 1, characterized in that, The central thickness CT1 of the first lens, the edge thickness ET1 of the first lens, the central thickness CT2 of the second lens and the edge thickness ET2 of the second lens satisfy: 0.3 < (CT1 / ET1) / (CT2 / ET2) < 0.

6.

9. The optical lens according to claim 1, wherein The object side end clear aperture semi-diameter CSD11 of the first lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.25 < CSD11 / IH < 0.3.

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