Optical lens

Abstract

The invention provides an optical lens, which sequentially comprises a first lens with negative focal power from an object side to an imaging surface along an optical axis, a second lens with negative focal power, a third lens with positive focal power and a fourth lens with negative focal power from the object side to the imaging surface, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a plane; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, and the image side surface of the fifth lens is a concave surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a convex surface; the object side surface of the seventh lens is a convex surface near the optical axis, and the image side surface of the seventh lens is a concave surface near the optical axis; and the object side surface of the eighth lens is a convex surface in a paraxial position, and the image side surface of the eighth lens is a concave surface in a paraxial position. According to the optical lens provided by the invention, the imaging quality of the optical lens can be improved, the aberration is reduced, and the imaging quality of the optical lens is improved.

Description

Technical Field

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

[0002] With the continuous upgrading of drones, consumers have higher and higher requirements for drone functions. Ultra-high pixels, large apertures, and wide-angle shooting have become the main development trends of drones. In order to pursue high-quality imaging, mainstream drones currently use all-glass lenses, and the number of lenses has been upgraded from 5 to 6 to 7 to 8 to correct the light path. However, due to the constraints of glass lenses, the weight and volume of glass lenses are difficult to reduce, and all-glass lenses have encountered a bottleneck period. Since plastic lenses are thinner and lighter, and have good plasticity, lenses using plastic lenses can be effectively thinned and lightened. At the same time, combined with the advantages of plastic lenses, large field of view shooting can be achieved, while ensuring the amount of light entering the optical lens and the clarity of the image. It is expected to be applied in high-end drones and is the development trend of drone lenses in the future. However, how to better achieve the lens's large field of view, large target imaging, and high pixel performance is still an urgent problem to be solved. Summary of the invention

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

[0004] The technical solution adopted by the present invention is: An optical lens, composed of eight lenses, including: The first lens has a negative optical power, the object side surface of which is convex, and the image side surface of which is concave; The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave; The third lens has positive power, its object side surface is convex and its image side surface is flat; a fourth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a fifth lens element having negative optical power, whose image side surface is concave; a sixth lens having positive refractive power, whose object side surface is concave and whose image side surface is convex; The seventh lens element has a negative optical power, the object side surface of which is convex at the near optical axis, and the image side surface of which is concave at the near optical axis; An eighth lens having negative optical power, whose object side surface is convex at the near optical axis and whose image side surface is concave at the near optical axis; 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。

[0005] 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。

[0006] Further preferably, the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7.8 <IH / EPD<8.5。

[0007] 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。

[0008] Further preferably, the image side surface curvature radius R14 of the seventh lens and the focal length f7 of the seventh lens satisfy: -0.35 <R14 / f7<-0.25。

[0009] 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。

[0010] 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。

[0011] Further preferably, the image side surface curvature radius R12 of the sixth lens and the image side surface curvature radius R14 of the seventh lens satisfy: -1.2 <R12 / R14<-1。

[0012] 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.

[0013] Further preferably, the real image height IH corresponding to the semi-aperture CSD11 of the object side end of the first lens and the maximum field angle of the optical lens satisfies: 0.25 <CSD11 / IH<0.3。

[0014] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical focal lengths. Through specific surface shape matching and reasonable optical focal length distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as a large field of view, miniaturization, a large target surface, and high pixels. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0016] Figure 2 Graph showing the field curvature of the optical lens in Embodiment 1 of the present invention.

[0017] Figure 3 4 is a distortion curve diagram of the optical lens in Example 1 of the present invention.

[0018] Figure 4 Graph showing longitudinal chromatic aberration of the optical lens in Example 1 of the present invention.

[0019] Figure 5 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0020] Figure 6 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0021] Figure 7 4 is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0022] Figure 8 4 is a distortion curve diagram of the optical lens in Example 2 of the present invention.

[0023] Fig. 9 Graph showing longitudinal chromatic aberration of the optical lens in Embodiment 2 of the present invention.

[0024] Fig.10 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0025] Fig.11 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0026] Fig.12 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0027] Fig.13 3 is a distortion curve diagram of the optical lens in Example 3 of the present invention.

[0028] Fig.14 4 is a longitudinal chromatic aberration curve of the optical lens in Example 3 of the present invention.

[0029] Fig.15 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0030] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0031] In order to better understand the present application, a more detailed description will be made of various aspects of the present application 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 are not intended to 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.

[0032] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0033] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. 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 shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0034] 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 is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0035] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0036] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0037] 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 the embodiments.

[0038] The optical lens provided by the embodiment of the present invention is composed of eight lenses, which are successively 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 along the optical axis from the object side to the imaging surface.

[0039] In some embodiments, 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 negative optical power, its object side is convex, and its image side is concave. The third lens may have a positive optical power, its object side is convex, and its image side is flat. 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 concave, and its image side is convex. The seventh lens may have a negative optical 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 optical power, its object side is convex near the optical axis, and its image side is concave near the optical axis.

[0040] 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.

[0041] In some embodiments, the optical lens may further include a filter, and the filter 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 the normal imaging.

[0042] 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 of the chip, but also achieve high-pixel imaging of the lens, improving the lens resolution and the receiving field of view.

[0043] 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 of the lens is set as a negative lens, providing a negative bending force for the lens, which is conducive to the lens obtaining more object space information, that is, conducive to increasing the field of view angle of the lens; through the design of parameters, the ratio of f1 and f is controlled to obtain a reasonable configuration, so that the lens can capture the light beam incident at a large angle, expand the field of view angle range of the lens, and achieve the low-sensitivity and miniaturized design of the lens; of course, the effective focal length of the first lens is reasonably configured to effectively balance the chromatic aberration of the lens and reduce the performance sensitivity of the lens.

[0044] 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 conducive to realizing large target surface imaging and improving the image plane brightness of the lens. When the lens exceeds the upper limit of the above relational expression, the entrance pupil diameter of the lens is small, which reduces the width of the light beam incident on the lens and is not conducive to improving the image plane brightness; when the lens is lower than the lower limit of the above relational expression, the image plane area of the optical lens is small, reducing the field of view range of the lens and is not conducive to matching with the chip, and it is easy to produce vignetting.

[0045] 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.

[0046] 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 conducive to correcting marginal aberration and slowly raising the marginal rays, which is conducive to realizing a large target surface.

[0047] In some embodiments, 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. Meeting the above conditions can effectively control the shape of the first lens, reduce the contribution of the first lens to higher-order aberrations, and enable the lens to have better resolution.

[0048] 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. Meeting the above conditions and reasonably distributing the optical power of the seventh lens can make the light rays smoothly enter the image plane after being lifted upward, which is beneficial to achieving a large target surface and at the same time is beneficial to correcting the residual aberration of the lens, further improving the imaging quality.

[0049] In some embodiments, 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. Meeting the above conditions and reasonably controlling the ratio of the image-side curvature radius of the sixth lens to the image-side curvature radius of the seventh lens can effectively control the assembly step difference between the sixth lens and the seventh lens within a reasonable range, which is convenient for processing and assembly. At the same time, it can relatively easily balance the aberration of the lens and improve the imaging quality of the lens.

[0050] 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. Meeting the above conditions, by controlling the central thickness and edge thickness of the first lens, as well as 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, thereby optimizing 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 rays passing through the first lens and the second lens have a small deflection angle, thereby reducing the generation of stray light in the lens, and then excellent imaging performance can be guaranteed; at the same time, reasonable surface shape changes can optimize the processing technology of the lens and reduce the design and assembly sensitivity of the first lens and the second lens.

[0051] In some embodiments, the object-side end clear aperture CSD11 of the first lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.25 < CSD11 / IH < 0.3. Meeting the above conditions, since the first lens mainly functions to converge light rays, the larger the aperture of the first lens, the better the light-gathering effect; however, a larger aperture will increase the overall size of the lens. Therefore, it can be ensured that the aperture of the first lens and the image height of the lens are within a suitable range, thereby controlling the aperture of the first lens so that the illuminance, field angle, and size are balanced.

[0052] 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.

[0053] 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. By satisfying 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 it is easy to process and form the first lens. In addition, it is beneficial to correct the spherical aberration of the lens and improve the imaging quality.

[0054] 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. By satisfying the above conditions, the spherical aberration of the lens can be corrected and the imaging quality can be improved; 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 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 incidence of the edge field of view onto 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.

[0055] 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 of the object side end of the first lens satisfy: 4.8 < CSD11 / SAGX11 < 5.2. By satisfying the above conditions, it is possible to avoid the surface shape of the object side of the first lens from being too curved, which is beneficial for large-angle light to enter the lens, thereby being beneficial for 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 for reducing the processing difficulty of the first lens and avoiding the situation of uneven coating caused by the overly 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 for reducing the risk of ghost images.

[0056] In some embodiments, the central thickness CT8 of the eighth lens and the clear aperture semi-diameter CSD82 of the image side end of the eighth lens satisfy: 0.1 < CT8 / CSD82 < 0.25. By satisfying the above conditions, the ratio of the central thickness of the eighth lens to the clear aperture can be reasonably distributed, 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 for improving the formability of the eighth lens during processing.

[0057] In some embodiments, the optical lens satisfies the conditional formula: 3.5 mm < f < 4.5 mm, 130° < FOV < 140°, 11 mm < TTL < 12 mm, 2.5 < Fno < 2.8, 12 mm < IH < 12.5 mm; 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, large target surface, etc.

[0058] In some embodiments, all eight lenses in the optical lens can 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 a combination of eight glass and plastic materials, 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 use of glass material for the third lens can improve the thermal stability of the optical lens, reduce aberration and distortion, and make the imaging of the optical lens clearer and sharper.

[0059] 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.

[0060] In various embodiments 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 equations: ; 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, H are the surface coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order respectively.

[0061] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter 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 other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0062] Example 1 See also Figure 1 , which is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention, wherein the optical lens comprises, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, an aperture 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.

[0063] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave; The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave; The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is flat; The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface S8 is convex; The fifth lens L5 has negative refractive power, its object-side surface S9 is convex at the near optical axis, and its image-side surface S10 is concave; The sixth lens L6 has positive refractive power, its object-side surface S11 is concave, and its image-side surface S12 is convex; The seventh lens L7 has negative refractive power, an object-side surface S13 thereof is convex at the near optical axis, and an image-side surface S14 thereof is concave at the near optical axis; The eighth lens L8 has negative refractive power, its object-side surface S15 is convex at the near optical axis, and its image-side surface S16 is concave at the near optical axis; The object side surface S17 and the image side surface S18 of the filter G1 are both planes; The imaging surface S19 is a plane.

[0064] 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.

[0065] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0066] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0067] Table 1-2 In this embodiment, the field curvature curve, distortion curve, longitudinal chromatic aberration curve, and vertical axis chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 shown.

[0068] Figure 2 The field curvature curve of the optical lens 100 in this embodiment is shown, which represents the field curvature of light 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 ±0.1mm, indicating that the optical lens 100 can correct the field curvature well.

[0069] Figure 3 The distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion of different field angles on the imaging surface, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the distortion value is controlled within -35%~0, indicating that the optical lens 100 can correct the distortion well.

[0070] Figure 4 The longitudinal chromatic aberration curve 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 ±0.03mm, indicating that the optical lens 100 can correct the longitudinal chromatic aberration well.

[0071] Figure 5 The vertical axis chromatic aberration curve 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 surface, the horizontal axis represents the vertical axis 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 vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm, indicating that the optical lens 100 can correct the vertical axis chromatic aberration well.

[0072] Example 2 See also Figure 6, shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0073] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0074] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0075] Table 2-2 In this embodiment, the field curvature curve, distortion curve, longitudinal chromatic aberration curve, and vertical axis chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Fig. 9 , Fig.10 shown.

[0076] from Figure 7 It can be seen that the field curvature of the meridian 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.

[0077] from Figure 8 It can be seen that the distortion value is controlled within -40%~0, which means that the optical lens 200 can correct the distortion well.

[0078] from Fig. 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.

[0079] from Fig.10 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3μm, indicating that the optical lens 200 can correct the vertical axis chromatic aberration well.

[0080] Example 3 See also Fig.11 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the object side surface S9 of the fifth lens L5 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0081] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0082] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0083] Table 3-2 In this embodiment, the field curvature curve, distortion curve, longitudinal chromatic aberration curve, and vertical axis chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.12 , Fig.13 , Fig.14 , Fig.15 shown.

[0084] from Fig.12 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.05mm, indicating that the optical lens 300 can correct the field curvature well.

[0085] from Fig.13 It can be seen that the distortion value is controlled within -40%~0, indicating that the optical lens 300 can correct the distortion well.

[0086] from Fig.14 It 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.

[0087] from Fig.15 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3μm, indicating that the optical lens 300 can correct the vertical axis chromatic aberration well.

[0088] Please refer to Table 4, which shows 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 real image height IH corresponding to the maximum field of view angle, the chief ray incident angle CRA at the maximum image height, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0089] Table 4 In summary, the optical lens provided by the present invention has at least the following advantages: (1) Through specific surface shape settings and reasonable optical focal length distribution, the overall length of the optical lens can be effectively shortened, which is conducive to better miniaturization of the optical lens; at the same time, it has a large field of view, improving the lens resolution and receiving field of view.

[0090] (2) The large target surface characteristic of the lens can be realized, and it can match the imaging chip with a larger target surface to achieve high-definition imaging. In addition, the increase in the target surface can make the pixel distribution more sparse (that is, the pixel size is larger), which can effectively reduce noise even in darker environments, and the dynamic range will be wider. More details can be retained in the dark area, thus presenting a clearer shooting effect. At the same time, it can also reasonably correct the overall aberration of the optical lens, so that the optical lens has high pixels and improves the imaging quality of the optical lens.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0092] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which 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 attached claims.

Claims

1. An optical lens, consisting of eight lenses, characterized in that: Along the optical axis from the object side to the imaging surface, it includes: The first lens has a negative optical power, the object side surface of which is convex, and the image side surface of which is concave; The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave; The third lens has positive power, its object side surface is convex and its image side surface is flat; a fourth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a fifth lens element having negative optical power, whose image side surface is concave; a sixth lens having positive refractive power, whose object side surface is concave and whose image side surface is convex; The seventh lens element has a negative optical power, the object side surface of which is convex at the near optical axis, and the image side surface of which is concave at the near optical axis; An eighth lens having negative optical power, whose object side surface is convex at the near optical axis and whose image side surface is concave at the near optical axis; 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。 2. 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: -2.1 <f1 / f<-1.3。 3. The optical lens according to claim 1, characterized in that: The real image height IH corresponding to the maximum field 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, characterized in that: 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, characterized in that: The image side surface 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, characterized in that: 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 effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -1.65 <f7 / f<-1.5。 8. 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。 9. The optical lens according to claim 1, characterized in that: 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.

10. The optical lens according to claim 1, characterized in that: The semi-aperture CSD11 of the object side of the first lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.25 <CSD11 / IH<0.3。

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